JPWO2001099168A1 - Semiconductor device and semiconductor device manufacturing method - Google Patents

Abstract

(57) [Abstract] A method for manufacturing a semiconductor device having a multilayer wiring structure, in which at least one insulating film has a surface area of 500 μm2 or ^more and a set of conductive parts with a wiring width of 1.0 μm or less, includes a polishing step (501) for planarizing the insulating film surface by chemical mechanical polishing, a chemical cleaning step (502) for cleaning the planarized insulating film surface with a cleaning chemical, and a rinsing step (503) for removing the cleaning chemical with a rinse. In the rinsing step, water having a dissolved oxygen concentration suppressed to 6 ppm by weight or less is used as the rinse.

Description

Detailed Description of the InventionTechnical Field The present invention relates to a semiconductor device having a multilayer wiring structure and a method for flattening the surface of each insulating film.
A polishing process by chemical mechanical polishing (CMP) to achieve smoothness, and the associated cleaning
The present invention relates to a method for manufacturing a semiconductor device having a multilayer wiring structure, including a cleaning step and a rinsing step.Background technologyIn recent years, there has been an increasing demand for faster and larger capacity semiconductor devices.
To meet this demand, we have developed a semiconductor device with a multilayer wiring structure that can achieve high density devices.
In semiconductor devices with multilayer wiring structures, each layer has a predetermined
The conductor pattern is formed by metal wiring, metal plugs, and
It consists of conductive parts such as pads. Metal plugs are used to connect metal wiring on different layers.
(made of a metal material filled in the connection holes) is provided.
To achieve this, it is desirable to make the wiring width of the metal wiring finer.
For metal wiring, the reduction of resistance and improvement of electromigration resistance are required.
Therefore, it is required to be a good conductor and to be resistant to electromigration.
Metal wiring and plugs made of highly conductive Cu or Cu alloys are being developed.
A method for forming metal wiring and plugs made of Cu or Cu alloy in multilayer wiring.
The Damascene method is known as one of the methods.
Ba, C. W. Kaanta et. al. , VMIC Conf. Proc. 8
, p. 144 (1991). In the damascene method, a layer 1 with metal wiring and plugs is formed as follows:
First, an insulating film is grown on a substrate, and then metal wiring is formed on the insulating film.
The etching is performed to form wiring grooves for receiving the wiring and/or contact holes for later receiving plugs.
Next, a wiring material is deposited in the wiring groove and the connection hole,
In the finished product, metal wiring and plugs are formed. At this time, the wiring on the insulating film
The wiring material is deposited even in areas where no grooves or contact holes are formed.
The wiring material is removed by polishing using the CMP method.
The insulating film and the metal wiring and plug formed in the insulating film are arranged so as to form a flush upper surface.
The surface is then planarized to form a predetermined conductive portion.
The wiring grooves and corresponding connection holes are formed by filling the wiring material for each layer and then
They are formed separately by the subsequent CMP polishing process. In contrast, the lower part is formed so as to open into the wiring groove formed in one insulating film.
A connection hole is formed in the insulating film, and wiring material is deposited in the wiring groove and the connection hole at the same time.
Then, the insulating film is subjected to CMP polishing.
The CMP method is also known. In the CMP polishing process, first, a slurry containing silica, alumina, etc. is used.
The substrate surface is polished and flattened by the polishing. If necessary, the substrate is then polished using pure water.
The surface is polished. During the polishing process, silica and alumina themselves as well as the polished gold
The surface of the semiconductor substrate is contaminated by metals from metal wiring and plugs.
Contamination of semiconductor substrates by substances affects the electrical characteristics of semiconductors and reduces the reliability of devices.
Therefore, after the CMP polishing process, the metal is removed from the semiconductor substrate surface.
A cleaning process is required to remove impurities. In the cleaning process, a specific cleaning solution is used to remove metal impurities from the substrate surface.
Then, as a process following the cleaning process, the cleaning chemical solution is removed.
The cleaning solution is rinsed with pure water to remove metal impurities.
In order to remove the metal, it is necessary to use a chemical that can dissolve the metal.
However, in the past, the cleaning process required polishing because the cleaning chemicals had a strong ability to dissolve metals.
This has led to the problem of corrosion of the conductive parts exposed on the surface of the layer after the process. As a means of suppressing oxidation and corrosion of electronic components during cleaning,
In the publication of No. 4-40270, electronic components are washed with pure water having a reduced dissolved oxygen concentration.
However, cleaning with pure water is not effective for CMP polishing.
Metal contamination after this process cannot be removed.
In Japanese Patent Laid-Open No. 10-128253 and Japanese Patent Laid-Open No. 6-318584,
As a method to prevent corrosion and oxidation of electronic components, etc., cleaning agents are used after cleaning electronic components.
Use pure water with a reduced dissolved oxygen concentration as a rinse solution to remove the liquid.
However, the techniques disclosed in these documents are generally
This relates to a rinse solution used after the cleaning process of electronic components, and is suitable for CMP polishing.
The presence of cleaning chemicals with metal dissolving ability, such as those used in the cleaning process after the polishing process,
In contrast, Japanese Patent Laid-Open No. 10-72594 describes the cleaning process involved in the adoption of a CMP polishing process.
To reduce the corrosion problem that occurs during the cleaning process,
Use a cleaning solution containing an organic acid having a xyl group and a complexing agent such as EDTA.
The use of an organic acid with a relatively low metal dissolving ability can prevent the surface of the metal wiring from being damaged.
At the same time, according to Japanese Patent Laid-Open Publication No. 10-72594, metal dissolution
Even if an organic acid with low activity is used, by adding a complexing agent, it can be used as a cleaning agent.
However, the cleaning process is carried out using organic acids with low metal dissolving ability as cleaning chemicals.
Even if the conductive part of the layer has undergone the cleaning and rinsing processes after the CMP polishing process,
In some cases, there was a problem of localized loss of wiring material, i.e. corrosion.
The inventors have found that such localized metals are removed in the rinsing step rather than the cleaning step.
We discovered that corrosion occurs. Figure 9 shows a schematic diagram of localized corrosion of metal wiring that previously occurred during the rinsing process.
FIG. 9 shows the CMP polishing process and the subsequent cleaning and rinsing processes.
After the process, a predetermined conductor pattern is embedded in the insulating film 100.
The conductive pattern is a conductive part formed on the same layer.
The metal wiring 101 is made up of a metal wiring 102 and a metal plug 104.
The pads 102 and 101 are electrically connected to each other on the same layer, and the conductive pattern
The pads form a set of conductive portions, and the edges of the metal wiring 102 are locally corroded.
Although localized corrosion occurs at the edges of 101, localized corrosion over a large area is not a problem.
The metal wiring 103 and the insulating layer 104 are not shown in the figure for the sake of simplicity.
The other metal wirings 103 are electrically connected to each other, forming a conductive pattern.
The metal wiring 103 and the other metal wiring 103 form another set of conductive parts.
Electrical connection is made to the metal wiring 103 through a metal plug 104 formed in the lower layer.
This is achieved through metal wiring 105 of another layer that is passed through. The inventors have found that the edges of the conductive parts, which have a relatively large area, and the conductive parts that are electrically connected to each other
The conductive layer is formed at the edge of a set of conductive parts having a relatively large area in the same layer.
Specifically, it was noticed that corrosion occurred in the 500 μm²Has a surface area of more than
The edges of the conductive parts are electrically connected to each other and are 500 μm thick in the same layer.²The above
At the edge of a set of conductive parts having a surface area, the metal wiring 102 of FIG.
As can be seen from the graph, local corrosion has progressed significantly.
No corrosion occurs because a set of conductive parts including the metal wiring 103 is in the layer shown in FIG.
500 μm²However, this is because the surface area is not large enough.
Even if a set of conductive parts does not include wires and consists of only wiring, the total number of conductive parts on the same layer is 50.
0 μm²If the surface area is greater than this, localized corrosion will occur during the rinsing process.
Metal corrosion in aqueous solutions generally occurs when hydrogen ions and dissolved oxygen in the solution act as oxidizing agents.
The cathodic reduction reaction occurs when the metal acts as a catalyst on the metal surface, and the metal is oxidized.
The local cell reaction is a combination of the anodic dissolution reaction in which the metal is dissolved in the aqueous solution.
For example, if the metal is Cu and the oxidant is dissolved oxygen, the anodic dissolution reaction proceeds as follows:
The reaction is represented by formula (I), and the cathodic reduction reaction is represented by formula (II).
The points where the cathode reaction is likely to occur are called cathode reaction active points, and the points where the anode reaction is likely to occur are called cathode reaction active points.
The locations where the anode reaction is likely to occur are called anodic reaction active points. The distribution of both reaction active points varies depending on the metal surface.
The physical and chemical state of the lattice structure and the concentration of the solution in contact with it change depending on the
. Cu → Cu²⁺+ 2e⁻ (I) 1/2O₂+ H₂O + 2e⁻→ 2OH⁻(II) In the CMP polishing process and the associated cleaning and rinsing processes, an aqueous solution is used.
Therefore, if the metal wiring is made of Cu, corrosion of the Cu wiring may occur.
Corrosion occurs due to a combination of anodic reaction (I) and cathodic reaction (II).
The reaction is thought to proceed as a condensed water reaction.
When this occurs almost uniformly on the surface of the Cu wiring, the Cu wiring corrodes almost uniformly.
On the other hand, when both reactions occur locally, Cu at the anode reaction active point
The dissolution of the copper wiring progresses locally, causing local corrosion of the copper wiring, i.e., local disappearance.
Japanese Patent Laid-Open No. 10-72594 discloses a method for dissolving metals by using an inorganic acid instead of a conventional inorganic acid having a high metal dissolving ability.
It is disclosed that an organic acid having low metal dissolving ability is used in combination with a complexing agent.
The driving force for the metal dissolution reaction, i.e., the metal dissolution ability, is relatively low, and this is the effective
By using it as one of the components, uniform corrosion of metal wiring is suppressed. However, when the cleaning process is carried out using an organic acid with low metal dissolving ability as a cleaning solution,
Even if this is the case, the metal in FIG. 9 of the conductor pattern of the layer that has undergone the subsequent rinsing process
The wiring 102 is electrically connected to each other and has a width of 500 μm in the same layer.²The above
a set of conductive portions having a surface area of 500 μm²The arrangement of conductive parts having a surface area of
The wire material is locally corroded. During the rinsing process, the concentration of the cleaning solution remaining on the substrate surface gradually decreases.
, inevitably passing through the ultra-low concentration range and reaching approximately 0, but especially when the cleaning chemical concentration is 4.70
x10⁻⁴~1.96 x 10⁻⁷Localized corrosion progresses when the concentration is in the range of mol/l.
The inventors have clarified that in the ultra-low concentration range,
They are electrically connected to each other and are 500 μm thick in the same layer.²A set of conductive materials with a surface area of more than
Electrical part 500 μm²On the surface of the conductive part having a surface area of 1000 or more, the anode reaction
The reactive sites are particularly localized at the edges of the metal wiring, i.e., in a narrow area, and the cathodic reaction
The active sites are distributed over a wide area on the metal wiring and/or other surfaces of the pads.
This causes an extreme difference in the reaction rate per unit area between the two reactions, resulting in local
The reaction rate per unit area is the anodic reaction
(I) is larger than the cathodic reaction (II), and as a result, the anodic reaction activity
At these points, a dissolution reaction occurs locally, causing local corrosion.
However, the same layer is 500 μm²The edges of a set of conductive parts having a surface area of less than
Localized corrosion of the wiring material is extremely small. To prevent such corrosion during the rinsing process, benzotriazole, etc.
When a rinse solution containing the above corrosion inhibitor added to pure water is used, the localized corrosion described above is suppressed.
However, a new problem arose: the use of pure water containing a corrosion inhibitor in the rinsing process.
In the subsequent drying process, only the pure water evaporates, and most of the corrosion inhibitor remains on the surface of the semiconductor substrate.
In this state, the next insulating film is deposited on the surface of the substrate.
If the insulating film is used, the corrosion inhibitor may be sandwiched between the conductive portion and the insulating film.
, the adhesive strength between these layers decreases, causing peeling at the relevant locations.
Thus, using corrosion inhibitors in the rinse process creates new problems.
This is undesirable as it can cause smearing. On the other hand, the same problem can occur in the CMP polishing process using pure water.
It was also found that the polishing liquid used in the previous polishing process and adhering to the surface of the semiconductor substrate
In the process of replacing the polishing solution with pure water, the concentration of the polishing solution gradually decreases and passes through the ultra-low concentration range.
Even in this ultra-low concentration range, local corrosion occurs during the rinsing process.
The same problem occurs when the layers are electrically connected to each other and the thickness is 500 μm.²End
and a pair of conductive edges having a surface area of 500 μm²Conductor with a surface area of more than
Localized corrosion occurs at the edges of electrical parts.Disclosure of the Invention The object of the present invention is to provide a semiconductor device that can eliminate or at least reduce the above-mentioned problems.
Another object of the present invention is to provide a method for manufacturing a vise. Another object of the present invention is to provide a structure that can eliminate or at least reduce the above-mentioned problems.
The object of the present invention is to provide a semiconductor device having a conductor pattern in at least one insulating film.
a multilayer wiring structure including at least one pair of electrically connected conductive parts;
A method for manufacturing a semiconductor device is provided, the method comprising:
a polishing step for planarizing the conductive portion together with the insulating film;
a chemical cleaning step for cleaning the surface of the insulating film with a cleaning chemical;
and a rinsing step for removing the residue with a solvent,
Water having an oxygen concentration of 6 ppm by weight or less is used as a rinse solution. According to a second aspect of the present invention, a conductive pattern in at least one insulating film is
a multilayer wiring structure including at least one pair of electrically connected conductive parts;
A method for manufacturing a semiconductor device is provided. The method includes forming an insulating film on a substrate.
and a pattern forming step for forming wiring grooves and connection holes in the insulating film.
forming a trench; and depositing a metal material on the insulating film so as to fill the wiring trench and the connection hole.
and a metal film forming step of adhering the metal material filled in the wiring groove and the connection hole.
A polishing process for removing the metal film by chemical mechanical polishing so that the metal film remains as a conductive portion.
a cleaning step for cleaning the polished insulating film with a cleaning chemical;
a rinsing step of removing the cleaning chemical solution with water having a concentration of 6 ppm by weight or less;
and a drying step for removing the water from the rinsing step. Preferably, the dissolved oxygen concentration of the water used as the rinsing liquid is 4 ppm by weight or less. Preferably, the conductive pattern is made of Cu or a Cu alloy. Preferably, the surface area of the set of conductive portions is 500 μm²That's all. In one embodiment of the present invention, the set of conductive parts includes a pad and a conductive part directly connected to the pad.
and interconnections connected to each other. In another embodiment, the set of conductive portions in the insulating film includes a plurality of interconnections.
The plurality of wirings are connected to each other via a conductor pattern in an insulating film below.
They are electrically connected to each other. Alternatively, the set of conductive portions may be a single wiring that is bent or branched.
It may be composed of different parts. More preferably, the width of the wiring of the conductive part is 1.0 μm or less. Preferably, the cleaning chemical used in the cleaning process is an organic acid, inorganic acid, or alkali.
More preferably, the organic acid is oxalic acid, malolactic acid, or the like.
Acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, tartaric acid,
At least one selected from the group consisting of enoic acid, malic acid, acetic acid, and salicylic acid
wherein the inorganic acid is dilute hydrofluoric acid and the alkali is ammonia. Preferably, the cleaning solution may further contain a surfactant. More preferably,
The surfactant is ammonium dodecyl sulfonate and/or n-dodecyl
The polishing step preferably includes a first polishing step using a chemical slurry, and a second polishing step using a chemical slurry.
A second polishing process in which polishing is performed using water in which the concentration of residual oxygen is suppressed to 6 ppm by weight or less.
More preferably, the dissolved oxygen concentration of the water used in the second polishing treatment is fourfold.
Preferably, the chemical slurry is a mixture of an organic acid, an inorganic acid, a complexing agent, and an abrasive grain.
According to the first and second aspects of the present invention, the dissolved oxygen concentration in the rinse solution can be reduced.
By reducing this, the rinse process that accompanies the chemical cleaning process after the CMP polishing process can be performed without the need for conventional methods.
This eliminates or at least reduces the localized corrosion problem that has been occurring in the past.
Therefore, the above-mentioned cathodic reaction (II) is suppressed, and therefore the anodic reaction (I)
Therefore, the cleaning agent remaining on the substrate surface during the rinsing process is reduced.
The concentration of the solution is in the ultra-low concentration range, and the potential anodic reaction active points of the Cu wiring are located at the wiring edge.
Even if the dissolved oxygen concentration is localized, it is believed that the local loss of Cu wiring can be suppressed. Similarly, in the second polishing step of the CMP polishing process,
For the same reason, using water as a polishing liquid prevents localized loss of metal wiring.
Furthermore, pure water with a reduced dissolved oxygen concentration is used in the rinsing process and second polishing process.
This can prevent localized loss, so adding a corrosion inhibitor to these pure waters is recommended.
This eliminates the need for corrosion inhibitors, which can cause corrosion between the wiring and the insulating film.
This avoids the problem of peeling that occurs when a conductive pattern is formed on a plurality of insulating layers.
A multilayer structure in which a conductive pattern in each insulating film includes a plurality of conductive portions.
A semiconductor device having a wiring structure is provided. In the semiconductor device, each conductor
The surface of each pair of conductive parts electrically connected to each other on the same insulating layer.
The area is 500 μm²Preferably, the wiring is made of Cu or a Cu alloy.
The conductive pattern of the film includes wiring having a width of 1.0 μm or less. With this configuration, the dissolved pure water used in the rinsing step and the second polishing step
Localized corrosion of conductive parts can be reduced without reducing the oxygen concentration.
The local corrosion of the conductive part in the first polishing step and the second polishing step is 500 μm.²More than 1000m2 surface area
The edges of the conductive parts having the same thickness are electrically connected to each other, and the conductive parts are 500 μm thick in the same layer.²Below
Since this occurs significantly at the edge of the conductive part having a surface area of
The surface area of a pair of electrically connected conductive parts on the same layer is 5
00μm²If the surface area is less than 500 μm, local corrosion can be avoided.
²In a conductive part or set of conductive parts less than 1, the anodic reaction (I) and the cathodic reaction (II) occur.
Since there is no significant difference in the reaction rate per unit area of reaction (II),
Through a series of processes including the polishing process, the subsequent cleaning process, and the rinsing process, local cell reactions
The wiring width of the conductive part is extremely small, and the problem of corrosion does not occur.
Below 1.0 μm, the problem of localized corrosion becomes extremely serious.
The rate of loss of wiring material due to the increase in wiring width is 1.0 μm or less.
Various features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.
It will become even clearer from the explanation.Best Mode for Carrying Out the InventionA preferred embodiment of the present invention will now be described in detail with reference to Figures 1 to 8.
Figure 1 is a flowchart showing the multilayer wiring formation process used in the present invention.
FIG. 2 is a cross-sectional view of a wafer undergoing the multi-layer wiring formation process of FIG.
In this embodiment shown in FIGS. 1 and 2, the dual dama
Multilayer wiring is formed using the SiO2 method. After the transistor fabrication process, the wafer 1 is first subjected to the interlayer film formation process.
In the interlayer film forming process 10, an insulating film 2 is formed on the wafer 1.
is grown as an interlayer film. Next, in the wiring trench/connection hole formation process 20, the insulating film 2 is etched.
Then, a wiring groove 3 for accommodating a metal wiring is formed, and the insulating film 2 is formed on the lower layer thereof.
A contact hole 4 is formed in the insulating film 2' to accommodate a plug later. Next, in the barrier film/seed Cu film formation process 30, a Cu film is formed on the surfaces of the wiring groove 3 and the contact hole 4.
A barrier film 5 is formed, and then a seed Cu film (not shown) is formed on the surface of the barrier film 5.
The barrier film 5 prevents Cu, which will be formed later, from diffusing into the insulating film 2.
The seed Cu film is required in the next plating step. Next, in the plating step 40, Cu is deposited as a wiring material in the wiring grooves 3 and the connection holes 4.
The Cu wiring 6 and Cu plug 7 are formed in the finished product by deposition.
The wiring material is deposited on the insulating film 2 in areas where the wiring grooves 3 are not formed.
As a whole, a metal film 8 is formed. Next, in the unnecessary material removal process 50, unnecessary wiring material and burrs deposited on the insulating film 2 are removed.
The insulating film 2 and the C film formed on the insulating film 2 are removed by scraping.
The upper surface is planarized so that it is flush with the u wiring 6.
The material removal process 50 includes a CMP process 501, a chemical cleaning process 502, and a rinsing process 503.
503 and drying process 504, which will be described later. Through these processes, the embedded wiring, i.e., the conductive part, is formed.
Pads may be formed in the same layer as the metal wiring using wiring material at the same time.
The pads may be formed separately as bonding pads using other metal materials.
Multilayer wiring is formed by repeating the above series of steps. Figure 3 shows the CMP step 501 of the unwanted material removal step 50 shown in Figure 1.
In the CMP process 501, as shown in FIG. 3, a polishing object fixed to a polishing head 51 is
The wafer 1 is pressed against a platen 53 having a polishing cloth 52 laid on its surface.
Then, while pouring the polishing liquid from the polishing liquid outlet 54, the polishing head 51 and the platen 53
The wafer 1 and the polishing cloth 52 are rotated to polish and flatten the surface of the wafer 1.
The polishing pressure during this period is set to, for example, 2 to 6 psi, and the polishing head 51 and the platen 53
, and are rotated in the same direction at a rotation speed of, for example, 50 to 100 rpm.
The surface of the wafer 1 is provided with grooves in a grid pattern or concentrically.
The CMP process of this embodiment includes a chemical slurry polishing process and a pure water polishing process.
In the slurry polishing process, the wafer 1 is polished using a chemical slurry as the polishing liquid.
In this process, the chemical slurry is discharged from the polishing liquid outlet 54 to a depth of 100 to 200 m.
The chemical slurry is supplied to the approximate center of the platen 53 at a flow rate of 1/min.
Using an aqueous solution containing naldic acid, lactic acid, colloidal silica (abrasive grains), and hydrogen peroxide
Benzotriazole may also be added to the chemical slurry as a corrosion inhibitor.
In the pure water polishing process after the chemical slurry polishing process, the dissolved oxygen concentration of wafer 1 is set to 6
Pure water reduced to less than ppm by weight, preferably less than 4 ppm by weight, is used as the polishing liquid.
In this process, pure water is poured from the pure water outlet 55 at a rate of 200 to 1500 kJ/min.
The liquid is supplied to the approximate center of the platen 53 at a flow rate of 0.00 ml/min.
The local corrosion of the metal wiring mentioned above can be suppressed.
For this purpose, vacuum degassing, membrane vacuum degassing, thermal degassing, and inert gases such as nitrogen and argon are used.
Alternatively, methyl ethyl ketone may be added to pure water.
By adding oxime, hydrazine, erythorbic acid, hydroquinone, etc.
Even if the CMP process is performed using a chemical cleaning agent, the dissolved oxygen concentration can be reduced. Figure 4 shows the chemical cleaning process 502 that is performed after the CMP process shown in Figure 3.
This chemical cleaning step 502 is performed to remove metal contamination and
This is done to remove contamination caused by abrasive grains.
The brush is sandwiched between a pair of rotating brushes 61 made of polyvinyl alcohol (PVA).
The rotating brush 61 is configured such that a cleaning solution is supplied to the brush portion while it is rotating.
The cleaning solution contains oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid,
Acid, maleic acid, fumaric acid, tartaric acid, citric acid, malic acid, acetic acid, salicylic acid
Select from organic acids such as dilute hydrofluoric acid (DHF), inorganic acids such as dilute hydrofluoric acid (DHF), and alkalis such as ammonia.
The cleaning solution also contains one or more active ingredients selected from the group consisting of dodecyl sulfone,
surfactants such as ammonium nitrate and ammonium n-dodecylbenzenesulfonate
The cleaning solution may also include a complexing agent such as EDTA.
After the surface of the wafer 1 is brushed with such a cleaning solution, the same rotating brush is used.
Pure water is supplied from the nozzle 61, and the cleaning chemical is added to the nozzle 61 to complete the chemical cleaning process 502.
The dissolved oxygen concentration of the pure water at this time is, for example, 6 times.
The dissolved oxygen concentration is 6 ppm by weight or less, preferably 4 ppm by weight or less.
When using pure water that has not been reduced to below 1000m, the cleaning solution concentration is in the ultra-low concentration range.
Before the temperature reaches 100°C, the rinsing by the rotary brush 61 is stopped.
The cleaning process does not necessarily have to be performed. Figure 5 shows the rinsing process 503 that is performed after the chemical cleaning process 502 shown in Figure 4.
In the rinse step 503, the dissolved oxygen concentration
The rinse solution outlet 71 is deionized water having a concentration of 6 ppm by weight or less, preferably 4 ppm by weight or less.
By reducing the dissolved oxygen concentration in this way, the cleaning chemical concentration
is in the ultra-low concentration range of 4.70 x 10⁻⁴~1.96 x 10⁻⁷When passing through mol/l
Even in this case, local corrosion of the metal wiring can be suppressed for the reasons mentioned above.
As a method for reducing the concentration, the pure water used in the above-mentioned CMP step 501 polishing process is used.
The same method as that for reducing the dissolved oxygen concentration in pure water can be used.
When the concentration of the cleaning chemical in the rinse solution adhering to the surface of the wafer 1 reaches approximately 0,
The rinsing step 503 is then completed. Figure 6 shows the drying step 504 that follows the rinsing step 503 shown in Figure 5. Drying step
In step 504, a heater (not shown) is installed above the wafer 1 and rotates at high speed.
The wafer is heated by the heater.
The used pure water is evaporated and the wafer 1 is dried. The above-mentioned CMP process 501, chemical cleaning process 502, rinsing process 503 and drying process
By going through the series of steps in step 504, the surface is sufficiently planarized and the gold
It is possible to prepare a wafer 1 with reduced metal corrosion.
The wafer 1 can be subjected to the interlayer film manufacturing process 10 shown in FIG.
Wiring is formed in the following manner. Figure 7 shows a multilayer wiring structure of a semiconductor device according to another embodiment of the present invention.
8 is a vertical cross-sectional view taken along line VIII-VIII in FIG. 7.
In this embodiment, a semiconductor device having multi-layer wiring is shown in FIG.
As shown in FIG. 7, the semiconductor device has a plurality of insulating films 70, 71, and 72 (see FIG. 8).
As shown, each of the insulating films 70, 71, and 72 has a plurality of pads 73 (only one shown) and
A plurality of wirings 74 and a plurality of connection holes 75 (metal plugs) are formed.
The formation patterns of the pads 73, wiring 74 and connection holes 75 differ for each insulating film.
Each pad 73 in an insulating film (for example, insulating film 70) is connected to all the pads in the same insulating film.
The wiring 74 is electrically isolated (see FIG. 8), and the adjacent insulating film (e.g., insulating
Through a connection hole 75 formed in the insulating film 71, another insulating film (for example, insulating film 72) is formed.
In a semiconductor device having a multilayer wiring structure as described above,
Therefore, each pad 73 is not connected to any wiring 74.
The surface area of the conductive part in the same layer is 500 μm²Therefore, the above phosphorus
Even if the concentration of dissolved oxygen in the pure water used in the etching process is high, the edge of the pad 73 as a conductive part
The battery reaction in which the anode and cathode are localized in the area other than the edge and the part
Even if corrosion occurs, the loss rate is small compared to the volume of the pad that can be electrically conducted.
This does not pose a problem. The present invention is particularly useful when forming Cu or Cu alloy wiring with a wiring width of 1.0 μm or less.
When the wiring width is 1.0 μm or less, local corrosion occurs.
This is because the effect of local corrosion is particularly pronounced at thicknesses of 0.5 μm or less.
This becomes a serious problem. Below, various examples and comparative examples will be explained to demonstrate the effectiveness of the present invention.
In this example and the comparative example, the width of the Cu wiring embedded in the wafer is 1.
The thickness was 0, 0.5, and 0.27 μm. The presence or absence of localized corrosion was confirmed in Example 6.
are electrically connected to each other and are 500 μm apart in the same layer.²With a surface area of more than
Each of the set of conductive parts was evaluated.²having a surface area of more than
A set of conductive parts was formed by a pad and a wiring electrically connected to the pad.
The evaluation was carried out by examining whether local corrosion occurred at the edge of the wiring.
Area is 500 μm²As long as it is a set of the above conductive parts, even if it is a conductive part of another mode,
, a phenomenon similar to those in these examples occurs. (Example 1) In this example, after the CMP process 501, one type of test sample is used in the chemical cleaning process 502.
The wafer 1 is cleaned using a cleaning solution containing a predetermined concentration of chemical.
The wafer 1 was rinsed with pure water in which the dissolved oxygen concentration was suppressed. In this example, one of the reagents in the cleaning solution was oxalic acid, an organic acid;
Succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, tartaric acid,
Citric acid, malic acid, acetic acid, salicylic acid, diluted hydrofluoric acid which is an inorganic acid, or
The alkaline ammonia water was used.
The residual oxygen concentration can be controlled by membrane vacuum degassing or inert gas (nitrogen or argon).
The concentration range was 1 to 4 ppm by weight. For example, in the chemical cleaning process 502, oxalic acid was added at 0.7 x 10⁻²mol/l
The wafer 1 was cleaned with a cleaning solution containing the following at a concentration:
The case where the wafer 1 is rinsed with pure water in which the residual oxygen concentration is controlled to 1 weight ppm, and the case where the wafer 1 is rinsed with nitrogen
The wafer 1 is rinsed with pure water in which the dissolved oxygen concentration is suppressed to 1 ppm by gas bubbling.
In addition, in the chemical cleaning process 502,
2.5 x 10 pinic acid⁻²Wafer 1 cleaned with a cleaning solution containing 1,2,4-trimethylsilyl methylcellulose at a concentration of 1.2 mol/L
For this, pure water with a dissolved oxygen concentration of 3 ppm by weight is used by a membrane vacuum degassing method.
When wafer 1 is rinsed with argon gas, the dissolved oxygen concentration is
The wafer 1 was rinsed with pure water containing 1 ppm of HCl.
Table 1 shows the results of the process after the chemical cleaning step 502 and the rinsing step 503 and drying.
The results of the condition on the surface of Cu wiring on the wafer dried in step 504 are shown.
In the wafer that has undergone the above process, the layers are electrically connected to each other and are 500 μm apart on the same layer.²
At the Cu wiring edge of a set of conductive parts having a surface area of 1000 or more, the wiring material is locally
For example, when cleaning with oxalic acid,
For wafers 1 cleaned with chemicals, the dissolved oxygen concentration is suppressed by membrane vacuum degassing.
Even when rinsed with purified water, the dissolved oxygen concentration is suppressed by bubbling nitrogen gas.
When rinsed with purified water, no localized loss was observed. (Example 2) In this example, after the CMP process 501, the chemical cleaning process 502 uses oxalic acid.
, malonic acid, succinic acid, glutaric acid or citric acid at a predetermined concentration, and further containing surfactant
Ammonium dodecyl sulfonate or n-dodecylbenzene sulfone as the agent
The wafer 1 was cleaned using a cleaning solution containing ammonium chloride at a concentration of 200 ppm by weight.
In the rinsing process 503, the dissolved oxygen concentration was reduced to 1.0 by a membrane vacuum degassing method.
Or pure water suppressed to 2 ppm by weight was used as the rinse solution. Table 2 shows the results of the sample that went through the chemical cleaning process 502 and the rinsing process 503 and then dried.
The results of the condition of the surface of Cu wiring on the wafer dried in step 504 are shown.
In the wafer that has undergone the above process, the layers are electrically connected to each other and have a thickness of 500 μm on the same layer.²Below
Localized loss of wiring material at the Cu wiring edge of a set of conductive portions having a surface area of
In this example, the membrane vacuum degassing method was used to suppress the dissolved oxygen concentration.
However, the dissolved oxygen concentration was suppressed by bubbling with nitrogen gas or argon gas.
It is also possible to do this. (Example 3) In this example, no localized loss occurred even after undergoing the process under the conditions of Example 1.
Seven types of wafers were selected from semiconductor devices with exposed wiring.
The wafers were immersed in the corresponding solutions for 30 minutes.
The cleaning chemical solution containing the same reagent as that used in the chemical cleaning step 502 is used to
The dissolved oxygen concentration of the pure water used for dilution was 100%.
This was suppressed by bubbling with gas. Table 3 shows the results of the ion exchange reaction on the surface of Cu wiring on a wafer that was dried after such immersion.
The wafer that has undergone the above process is electrically connected to each other.
, 500 μm in the same layer²At the Cu wiring edge of a set of conductive parts having a surface area of
No localized loss of wiring material was observed. (Example 4) In this example, no localized loss occurred even after undergoing the process under the conditions of Example 2.
Three types of wafers were selected from semiconductor devices with exposed wiring.
The wafers were immersed in the corresponding solutions for 30 minutes.
The cleaning chemical solution containing the same reagent as that used in the chemical cleaning step 502 is used to
The dissolved oxygen concentration of the pure water used for dilution was 100%.
This was suppressed by bubbling with gas. Table 4 shows the Cu on the wafer after this immersion and drying in the drying step 504.
The results of the state of the wiring surface are shown below. In the wafer that has undergone the above process, the electrical
are electrically connected to each other, and the same layer is 500 μm thick.²C of a set of conductive parts having a surface area of more than
No localized loss of wiring material was observed at the wiring edges. (Example 5) In this example, the dissolved oxygen concentration was set to 1 ppm during the pure water polishing process in the CMP process 501.
The dissolved oxygen concentration of the pure water was controlled as follows:
After such pure water polishing treatment, the surface is dried in a drying step 504.
An upper layer was laminated. Table 5 shows the wafer after undergoing the CMP process 501 and the drying process 504.
The results of the surface condition of the Cu wiring on the wafer are shown below.
They are electrically connected to each other and are 500 μm thick in the same layer.²A set of surfaces with a surface area of
No local loss of wiring material was observed at the edge of the Cu wiring in the conductive portion.
Table 5 shows the results of adhesion between Cu and the interlayer insulating layer when the upper layer is laminated.
No peeling of the layers occurred. (Example 6) In this example, the wiring width was increased within the same layer of a semiconductor device with a multilayer wiring structure.
is 1.0 μm or less and the surface area of the electrically connected conductive parts is 500 μm²less than
In this example, a wiring structure was formed in which the dissolved oxygen concentration was
Pure water with no suppressed concentration was used as the rinse solution. Table 5 shows the Cu wiring on the wafer after drying through this rinsing process.
The results of the surface condition of the wafer after the above process are shown in Fig. 1.
No localized loss of wiring material was observed. (Comparative Example 1) In this example, after the CMP process 501, one type of test sample was used in the chemical cleaning process 502.
The wafer 1 is cleaned using a cleaning solution containing a predetermined concentration of chemical.
The wafer 1 was rinsed with pure water that does not suppress the dissolved oxygen concentration. In this example, one type of reagent in the cleaning chemical solution was oxalic acid, an organic acid,
Succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, tartaric acid,
Citric acid, malic acid, acetic acid, salicylic acid, diluted hydrofluoric acid which is an inorganic acid, or
Ammonia water, which is alkaline, was used. Table 6 shows the results of the cleaning process 502 and rinsing process 503 followed by the drying process
The results of the condition of the surface of Cu wiring on the wafer dried in 504 are shown.
In the wafers that have undergone this process, the layers are electrically connected to each other and are 500 μm apart on the same layer.²End
The wiring material is locally corroded at the Cu wiring edge of a set of conductive parts having a surface area of
Eating, or localized disappearance, was observed. (Comparative Example 2) In this comparative example, in the cleaning process 502, the same composition as in Example 2, as shown in Table 7, was used.
The wafer 1 was cleaned using a cleaning solution containing the combined reagent.
In this case, pure water with no suppressed dissolved oxygen concentration was used as the rinse liquid. Table 7 shows the results of the drying process after the cleaning process 502 and rinsing process 503.
The results of the surface condition of the Cu wiring on the wafer dried in 504 are shown.
In the wafers that have gone through this process, they are electrically connected to each other and are 500 μm apart on the same layer.²The above
At the Cu wiring edge of a set of conductive parts having a surface area, local loss of wiring material is observed.
It was done. (Comparative Example 3) In this example, similar to Example 3, local consumption was not observed even after undergoing the process under the conditions of Example 1.
Seven types of wafers were selected from semiconductor devices with exposed Cu wiring that had no defects.
Each wafer was selected and immersed in the corresponding solution for 30 minutes.
The solution is a cleaning solution containing the same reagents as those used in the chemical cleaning step 502 for each wafer.
The chemical solution was prepared by diluting it with pure water that did not suppress the dissolved oxygen concentration. Table 8 shows the results of the immersion and subsequent drying of the Cu wiring on the wafer.
The wafer that has undergone the above process is electrically connected to each other.
, 500 μm in the same layer²At the Cu wiring edge of a set of conductive parts having a surface area of
Localized loss of wiring material was observed. (Comparative Example 4) In this comparative example, similar to Example 4, local consumption was not observed even after undergoing the process under the conditions of Example 2.
Three types of wafers were selected from semiconductor devices with exposed Cu wiring that had no defects.
Each wafer was selected and immersed in the corresponding solution for 30 minutes.
The solution is a cleaning solution containing the same reagents as those used in the chemical cleaning step 502 for each wafer.
The chemical solution was prepared by diluting it with pure water that did not suppress the dissolved oxygen concentration. Table 9 shows the results of the immersion and subsequent drying of the Cu wiring on the wafer.
The wafer that has undergone the above process is electrically connected to each other.
, 500 μm in the same layer²At the Cu wiring edge of a set of conductive parts having a surface area of
Localized loss of wiring material was observed. (Comparative Example 5) In this comparative example, the dissolved oxygen concentration was suppressed during the pure water polishing process in the CMP process 501.
Pure water without any polishing agent was used as the polishing liquid. Table 5 shows the polishing liquid after the CMP process 501 and the drying process 504.
The results of the surface condition of the Cu wiring on the wafer are shown below.
They are electrically connected to each other and are 500 μm thick in the same layer.²A set of surfaces with a surface area of
Localized loss of wiring material was observed at the edge of the Cu wiring in the conductive portion. (Comparative Example 6) In this comparative example, the dissolved oxygen concentration was suppressed during the pure water polishing process in CMP step 501.
However, it contains benzotriazole as a corrosion inhibitor at a concentration of 500 ppm by weight.
Pure water containing 100% ammonium nitrate was used as the polishing liquid. Table 5 shows the results of the polishing of Cu wiring on a wafer that had been dried after undergoing this CMP process.
The results of the surface condition are shown below. After the above process, the wafers are electrically connected to each other.
The same layer is connected to 500 μm²A set of conductive Cu wiring having a surface area of
No local loss of wiring material was observed at the edges.
When the layers are laminated, the adhesion between the Cu and the interlayer insulating layer is poor, and peeling of the laminated layers occurs.
Peeling occurred. (Comparative Example 7) In this comparative example, the wiring width was
is 1.0 μm or less, and the surface area of the electrically connected conductive part is 600 μm²is
In this example, the rinsing step in the unnecessary substance removal step 50
Pure water with no suppressed dissolved oxygen concentration was used as the rinse solution. Table 5 shows the results of the Cu wiring on the dried wafer after undergoing this rinsing process.
The results of the state on the surface are shown in Fig. 1. In the wafer that has undergone the above process, the edge of the Cu wiring is
However, localized loss of wiring material was observed. (Evaluation) According to this invention, during the process of manufacturing semiconductor devices with multilayer wiring structures,
In the pure water polishing process in the CMP process, pure water with a reduced dissolved oxygen concentration is used as the polishing liquid.
By using them together, they are electrically connected to each other and the same layer is 500 μm thick.²Below
A local area at the edge of a conductive part having a surface area of, for example, a Cu or Cu alloy wiring
The dissolved oxygen concentration is 6 ppm by weight.
The effect is shown below, but even lower concentrations are preferable. Desirable dissolved oxygen
The concentration is 4 ppm by weight or less. Furthermore, according to the present invention, the rinsing step introduced after the cleaning step associated with the CMP step
In this process, the dissolved oxygen concentration of the pure water used as a rinse solution is suppressed.
They are electrically connected to each other and are 500 μm thick on the same layer.²A surface area of more than
Localized corrosion at the edges of the pair of conductive parts, e.g., Cu or Cu alloy wiring.
According to another aspect of the present invention, the wiring width is 1.0 μm or less, and electrical wiring is performed in the same layer.
The surface area of each of the electrically connected conductive parts is 500 μm²The
This structure allows for the formation of an electrode pattern.
In the CMP process, the dissolved oxygen concentration is
The use of unsuppressed solutions can cause localized corrosion at the edges of metal wiring.
This means that local loss can be suppressed.

[Brief explanation of the drawings]

FIG. 1 is a flowchart showing a multilayer wiring formation process used in the present invention. FIG. 2 is a cross-sectional view of a wafer in each step of FIG. 1. FIG. 3 is a perspective view showing a chemical mechanical polishing step in the multilayer wiring formation process shown in FIG. 1. FIG. 4 is a perspective view showing a cleaning step performed after the chemical mechanical polishing step shown in FIG. 3. FIG. 5 is a perspective view showing a rinsing step performed after the cleaning step shown in FIG. 4. FIG. 6 is a perspective view showing a drying step performed after the rinsing step shown in FIG. 5. FIG. 7 is a plan view showing a wiring structure of a semiconductor device according to the present invention. FIG. 8 is a vertical cross-sectional view taken along line VIII-VIII in FIG. 7. FIG. 9 is a schematic diagram showing local corrosion of metal wiring that conventionally occurs during a rinsing step.

───────────────────────────────────────────────────── Continued from the front page (72) Inventor: Shigeru Suzuki 4-1 Kami-Odanaka, Nakahara-ku, Kawasaki, Kanagawa Prefecture No. 1, Fujitsu Limited (72) Inventor: Nobuaki Santo 4-1 Kami-Odanaka, Nakahara-ku, Kawasaki, Kanagawa Prefecture No. 1, Fujitsu Limited (72) Inventor: Motomori Miyajima 4-1 Kami-Odanaka, Nakahara-ku, Kawasaki, Kanagawa Prefecture No. 1, Fujitsu Limited (Note) This publication is based on the internationally published patent gazette issued by the International Bureau of International Patent Publication (WIPO). Please note that the effect of the international publication of the Japanese-language patent application (Japanese-language utility model registration application) related to this publication arises pursuant to Article 184-10, Paragraph 1 of the Patent Act (Article 48-13, Paragraph 2 of the Utility Model Act), and is unrelated to this publication.

Claims (23)

[Claims] [Claim 1] A method for manufacturing a semiconductor device with a multilayer wiring structure, in which a conductor pattern in at least one insulating film includes at least one set of conductive parts electrically connected to each other, comprising: a polishing step for planarizing the conductive parts together with the insulating film by chemical mechanical polishing; a chemical cleaning step for cleaning the planarized insulating film surface with a cleaning chemical; and a rinsing step for removing the cleaning chemical with a rinse liquid, wherein in the rinsing step, water in which the concentration of dissolved oxygen is suppressed to 6 ppm by weight or less is used as the rinse liquid. 2. The semiconductor device manufacturing method according to claim 1, wherein the water used as the rinse liquid has a dissolved oxygen concentration of 4 ppm by weight or less. 3. The method for manufacturing a semiconductor device according to claim 1, wherein the conductive pattern is made of Cu or a Cu alloy. 4. The semiconductor device manufacturing method according to claim 1, wherein the surface area of the set of conductive portions is 500 μm ² or more. 5. The method for manufacturing a semiconductor device according to claim 4, wherein the set of conductive portions includes a pad and a wiring directly connected to the pad. 6. The method for manufacturing a semiconductor device according to claim 5, wherein the width of the wiring of the conductive portion is 1.0 μm or less. [Claim 7] A semiconductor device manufacturing method as described in claim 4, wherein the set of conductive portions in the one insulating film includes a plurality of wirings, and these plurality of wirings are electrically connected to each other via a conductor pattern in an underlying insulating film. 8. The method for manufacturing a semiconductor device according to claim 7, wherein the width of each of said wirings is 1.0 μm or less. 9. The polishing step includes a first polishing process using a chemical slurry;
2. The method for manufacturing a semiconductor device according to claim 1, further comprising a second polishing step in which polishing is performed using water in which the dissolved oxygen concentration is suppressed to 6 ppm by weight or less. 10. The water used in the second polishing treatment has a dissolved oxygen concentration of 4 ppm by weight.
10. The semiconductor device manufacturing method of claim 9, wherein: [Claim 11] A method for manufacturing a semiconductor device with a multilayer wiring structure, in which a conductor pattern in at least one insulating film includes at least one set of conductive portions electrically connected to each other, comprising: an insulating film forming process for forming an insulating film on a substrate; a pattern forming process for forming wiring grooves and connection holes in the insulating film; a metal film forming process for attaching a metal material to the insulating film so as to fill the wiring grooves and connection holes; a polishing process for removing the metal film by chemical mechanical polishing so that the metal material filled in the wiring grooves and connection holes remains as conductive portions; a cleaning process for cleaning the polished insulating film with a cleaning solution; a rinsing process for removing the cleaning solution with water having a dissolved oxygen concentration of 6 ppm by weight or less; and a drying process for removing the water from the rinsing process. 12. The method for manufacturing a semiconductor device according to claim 11, wherein the water used as the rinse liquid has a dissolved oxygen concentration of 4 ppm by weight or less. 13. The method for manufacturing a semiconductor device according to claim 11, wherein the metal material is Cu or a Cu alloy. 14. Claim 1, wherein the surface area of said set of conductive portions is 500 μm ² or more.
2. The semiconductor device manufacturing method according to claim 1. 15. The semiconductor device manufacturing method according to claim 14, wherein the set of conductive portions includes a pad and a wiring directly connected to the pad. 16. The semiconductor device manufacturing method according to claim 15, wherein the width of the wiring of the conductive portion is 1.0 μm or less. [Claim 17] A semiconductor device manufacturing method as described in claim 14, wherein the set of conductive portions in the one insulating film includes a plurality of wirings, and these plurality of wirings are electrically connected to each other via a conductor pattern in an underlying insulating film. 18. The semiconductor device manufacturing method according to claim 17, wherein the width of each of said wirings is 1.0 μm or less. [Claim 19] The semiconductor device manufacturing method described in claim 11, wherein the polishing process includes a first polishing process using a chemical slurry and a second polishing process using water in which the dissolved oxygen concentration is suppressed to 6 ppm by weight or less. 20. The water used in the second polishing treatment has a dissolved oxygen concentration of 4 ppm by weight.
20. The semiconductor device manufacturing method of claim 19, wherein: [Claim 21] A semiconductor device having a multilayer wiring structure, which is formed by stacking a plurality of insulating films, each having a conductor pattern formed thereon, and the conductor pattern in each insulating film includes a plurality of conductive parts, and the surface area of each conductive part, or each set of conductive parts electrically connected to each other in the same insulating layer, is less than 500 ^μm2 . 22. The semiconductor device according to claim 21, wherein said wiring is made of Cu or a Cu alloy. 23. The semiconductor device according to claim 21, wherein the conductor pattern of each insulating film includes wiring having a width of 1.0 μm or less.