JP2000340533A - CMP processing equipment - Google Patents

Abstract

[PROBLEMS] To provide a CMP processing apparatus capable of polishing a polished surface of an object to be polished to an accurate flat surface regardless of presence or absence of dust between the object to be polished and a suction table. . An object to be polished is a suction table that rotates while adsorbing and holding the object to be polished, and a table that rotates while being pressed against the object to be polished, and moves the object to be polished.
Polishing slurry 3 supplied between the polishing surface 23a and the polishing surface 23a
Pad 3 for performing CMP processing on the surface 23a to be polished through
0. An elastic suction plate 38 is detachably attached to the support surface 37a of the suction table 37. Alternatively, the entire suction table 37 is formed of resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CMP (Chemical Mechanical) used mainly for flattening a thin film such as an insulating film or a metal film formed on the surface of an LSI device.
cal Polishing) It relates to processing equipment.

[0002]

2. Description of the Related Art In recent years, CMP processing has solved the problem of the depth of focus of lithography for miniaturization of device structures,
Reduction of wiring steps in manufacturing multilayer wiring LSI or C
Rapid development is progressing as a polishing technique capable of coping with new processes such as u wiring and SOI. CMP processing technology has begun to be applied in the manufacturing process of ULSI first in the United States because of its excellent flatness performance.
It is becoming the main technology of the flattening process of SI.

Next, the outline of the CMP processing apparatus will be briefly described. A general CMP processing apparatus has a configuration as shown in FIG. That is, a polishing slurry 2 made by mixing abrasive grains (fine particles) as a polishing agent in a solvent such as ammonia is supplied from a slurry supply device 4 to the polishing cloth 2 provided on the surface of the platen 1. Is done. For example, an object 7 to be polished such as a wafer is suction-held on the lower surface of the suction pad 9 of the polishing head 8 and pressed against the polishing pad 2 with a pressing force 11 from above while applying a rotational force 10. On the other hand, the polishing pad 2 is rotated together with the platen 1.

FIG. 4 is an explanatory view of the principle of the CMP processing, and for convenience, the vertical positional relationship is inverted from FIG. CMP processing is a high-speed, low-damage polishing technique utilizing both a chemical action and a mechanical action. That is, the ions 12 in the polishing slurry 3 are bonded to the thin film on the surface of the polishing object 7 by a chemical reaction, and
4 to perform a chemical action. On the other hand, the abrasive grains 13 in the polishing slurry 3 perform a mechanical action of mechanically removing the surface layer 14. The surface layer 14 acts as a cover to prevent the chemical reaction from proceeding deeply.

The polishing cloth 2 is made of a porous member lined with a rubber plate or the like, and has an uneven surface having a concave portion 2a and a convex portion 2b. It is held and supplied to the surface of the object 7 to be polished, and the convex portion 2b presses the ions 12 and the abrasive grains 13 against the surface of the object to be polished 7 to accelerate the above-described chemical action and mechanical action. The surface layer 14 formed by combining with the thin film on the surface of the polished object 7 is peeled off by the abrasive grains 13 by rotating the polished object 7 while being pressed against the polishing cloth 2. The surface of 7 is polished so that the entire surface becomes a precise flat surface.

[0006] This CMP processing is performed by flattening the interlayer insulating film 20 as shown in FIGS.
As shown in FIG. 2B, it is widely used for various purposes such as formation of metal wiring, furthermore, burying of wiring metal, uniform thinning of SIO layer or formation of capacitor. FIG. 3A shows a state in which a circuit pattern 19 is formed on a base oxide film 18 formed on the surface of a silicon wafer 17 and the circuit pattern 19 is covered with an interlayer insulating film 20. Have unevenness corresponding to the circuit pattern 19 on the surface thereof. Therefore, the interlayer insulating film 20
The wafer is polished by the above-mentioned CMP process and is flattened as shown in FIG.

FIG. 1A shows a silicon wafer 1.
7, a barrier film 21 having a predetermined shape having a concave portion is formed on the underlying oxide film 18 formed on the surface of the copper wiring portion 2.
2 has been formed. Unnecessary portions of the copper wiring portion 22 and the barrier film 21 are polished and removed by performing a CMP process to obtain a copper wiring portion 22 having a required shape as shown in FIG.

FIG. 6 shows an object 23 to be polished having a relatively large shape.
FIG. 2 is a schematic longitudinal sectional view showing a CMP processing apparatus used in a step of flattening a surface to be polished (in this case, an upper surface) 23a. As the object to be polished 23 of this CMP processing apparatus, a wafer or a hard disk having a relatively large shape is used. And so on. The suction table 24 for holding and rotating the workpiece 23 by suction is made of iron, is supported on a support base 27, and is rotated by a table driving motor.

A resin-made retainer ring 29 mounted and fixed on the support base 27 projects upward from the support surface (in this case, the upper surface) 24a of the suction table 24 by an amount substantially equivalent to the thickness of the object 23 to be polished. It is fitted into the outer peripheral portion of the suction table 24 in the above-described relative relationship. This retainer ring 29
Regulates the object to be polished 23 so as not to protrude from the support surface 24a of the suction table 24, and hangs a balun-type polishing pad 30 to be described later when the polishing pad 30 is moved to a position protruding to the side of the object 23. I do not support it.

The object 23 to be polished placed on the support surface 24a of the suction table 24 is
The vacuum suction device (not shown) sucks the air through the support surface 3 and vacuum-sucks the support surface 24a of the suction table 24. The retainer ring 29 prevents the support table 24a from deviating from the support surface 24a and is detachably fixed. It should be noted that FIG.
The illustration of the slurry supply device 4 for supplying the polishing slurry 3 shown in FIG.

The balun-type polishing pad 30 is provided with a polishing head 32 rotated by a pad driving motor 31.
And is bulged out of the polishing head 32 by compressed air. The outer surface of the polishing pad 30 is a processing surface 30 a having the same irregularities as the polishing cloth 2 shown in FIGS. 3 and 4.
Is pressed against the surface 23a to be polished of the object 23 while being rotated, and is moved in the horizontal direction as indicated by the arrow while maintaining the state, and the entire surface 23a of the object 23 is polished. Polish.

[0012]

The CMP processing apparatus is generally installed and used in a clean room. However, the CMP processing itself is performed in a processing atmosphere that is easily contaminated by polishing debris or foreign matter mixed in the polishing slurry 3. , Dust 34 is likely to be generated. for that reason,
As shown in FIG. 6, when dust 34 enters between the support surface 24a of the suction table 24 and the workpiece 23,
Due to the vacuum suction force acting on the object 23 and the pressure applied by the polishing pad 30, dust 34 on the object 23 is polished.
Is deformed into the state shown in the figure, which bulges upward.

At this time, the polishing pad 30 is polished so as to flatten the entire polished surface 23a of the polished object 23 including the portion swollen by the dust 34. Corresponding portions are extra polished to flatten the bulged portions. For this reason, in the polished object 23 after the processing, as shown in FIG. 7, the portion swollen by the dust 34 returns to its original state by its own elasticity, so that it can be visually confirmed on the polished surface 23a. Depression (generally called dimple) 2
5 occurs.

The object 23 to be polished after the above processing is formed by
As a result, the flatness of the polished surface 23a is lost, resulting in a defective product. Therefore, conventionally, the cleanness of the processing atmosphere in the clean room where the CMP processing apparatus is installed is increased, and cleaning for removing the dust 34 is performed. However, this is a factor that increases both the equipment cost and the running cost. ing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and polishes a polished surface of an object to be polished to an accurate flat surface regardless of whether dust enters between the object and the suction table. It is an object of the present invention to provide a CMP processing apparatus capable of processing.

[0016]

In order to achieve the above object, a CMP processing apparatus according to a first aspect of the present invention comprises a suction table that rotates while holding an object to be polished on a support surface, A polishing pad that moves while rotating while being pressed against the surface to be polished, and performs a CMP process on the surface to be polished through a polishing slurry supplied between the polishing table and the polishing table; An elastic suction plate is detachably attached to the support surface.

In this CMP processing apparatus, even if dust enters between the elastic attraction plate and the object to be polished, the dust is repelled when the object to be polished adheres to the elastic attraction plate. The plate is sunk while being deformed so as to be depressed with respect to the plate, so that the polished surface of the polished object does not deform into a swollen state regardless of the presence or absence of dust. Therefore, the polished surface of the object to be polished after processing does not have a dent due to the presence of dust, and the entire surface can be precisely flattened by the CMP processing using the polishing pad. In addition, since the object to be polished does not deform into a swollen state regardless of the presence or absence of dust, it is not necessary to increase the cleanliness of the clean room where the CMP processing device is installed, and the cleaning process of the suction table and the like is simplified. Therefore, both equipment costs and running costs can be reduced. In addition, since the elastic suction plate is provided on the suction table detachably,
When it deteriorates with use, it can be easily replaced as a consumable and can always maintain the required elasticity.

According to a second aspect of the present invention, there is provided a CMP apparatus which rotates while adsorbing and holding an object to be polished on a support surface, and a rotating table while being pressed against the surface to be polished of the object to be polished. A polishing pad that moves and CMP-processes the polished surface via a polishing slurry supplied between the polishing pad and the polished surface.

In this CMP processing apparatus, the same effects as those of the first invention can be obtained, and in addition, the suction table 41 formed entirely of resin has a larger size than the elastic suction plate of the CMP apparatus of the first invention. Because you can get a large elastic force,
There is an advantage that the dust can be more reliably settled in the suction table to prevent deformation of the object to be polished, and that the frequency of replacement can be reduced as compared with the elastic suction plate of the first invention. .

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic sectional view showing a CMP processing apparatus according to a first embodiment of the present invention. In FIG. 1, the same or equivalent parts as those in FIG. I do. The difference between the CMP apparatus of this embodiment and the conventional apparatus shown in FIG. 6 is that the thickness of the iron suction table 37 is made slightly smaller than that of the conventional apparatus, so that the suction table 24 becomes smaller. An elastic suction plate 38 having a thickness corresponding to the thickness of the suction table 37 is attached to the support surface 37a of the suction table 37 by an attaching means such as an adhesive, and suction holes 39 and 40 communicating with the elastic suction plate 38 and the suction table 37 are formed. Only the formed configuration. The elastic suction plate 38 is formed of, for example, rubber. In FIG. 3, the illustration of the slurry supply device 4 for supplying the polishing slurry 3 shown in FIG. 3 is omitted.

Therefore, in the above-mentioned CMP processing apparatus, even if dust 34 enters between the elastic suction plate 38 and the object 23, the object 23 is elastically moved by the vacuum suction force and the pressing force of the polishing pad 30. When the dust 34 comes into close contact with the upper surface of the suction plate 38, the dust 34 sinks while deforming the elastic suction plate 38, which is more elastic than the workpiece 23, so as to depress it. As a result, the polished surface 23a of the polished object 23 does not deform into a swelling state regardless of the presence or absence of the dust 34, so that the dent due to the presence of the dust 34 does not occur after the CMP processing. The entire surface is precisely flattened by the CMP process using the polishing pad 30. Therefore, this CMP processing apparatus can perform the CMP processing on the object 23 to be polished with a high yield.

As described above, in the above-mentioned CMP processing apparatus, even when the dust 34 enters between the polished object 23 and the elastic attraction plate 38, the polished object 23 can be subjected to the CMP processing with good yield. It is not necessary to increase the cleanliness of the clean room in which the processing device is installed, so that the process of cleaning the elastic suction plate 38 and the suction table 37 can be simplified, and both equipment costs and running costs can be reduced. In addition, since the elastic suction plate 38 is provided on the suction table 37 by a detachable attaching means such as an adhesive, if it is deteriorated with use, it can be easily replaced as a consumable to always provide the required elasticity. Can be maintained.

FIG. 2 is a circuit diagram showing a C according to a second embodiment of the present invention.
FIG. 2 is a schematic vertical sectional view of a main part showing the MP processing apparatus, in which the same or equivalent components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. CMP of this embodiment
The processing apparatus differs from the apparatus of the first embodiment only in the configuration in which the entire suction table 41 is formed of resin and the suction table 41 is provided with a suction hole 42.

In this CMP processing apparatus, the same effect as that of the first embodiment can be obtained, and in addition, the suction table 41 made of resin as a whole has the elastic suction plate 38 of the first embodiment. Since a greater elastic force can be obtained, the dust 34 can be more reliably sunk into the suction table 41 to prevent deformation of the object 23 to be polished, and the elasticity can be reduced as in the first embodiment. There is no need to align the suction holes 39, 40 when replacing the suction plate 38, and furthermore,
There is an advantage that the frequency of replacement can be reduced.

[0025]

As described above, according to the CMP processing apparatus of the present invention, the elastic suction plate is detachably attached to the support surface of the suction table, so that the space between the elastic suction plate and the object to be polished is removed. Dust penetrates into the elastic adsorption plate having elasticity and sinks while deforming so as to depress it, so that the polished surface of the object to be polished is deformed into a swelling state regardless of the presence or absence of dust. Nothing. Therefore, the surface to be polished of the object to be polished does not have a dent due to the presence of dust, and the entire surface can be precisely flattened by the CMP processing using the polishing pad, and a clean room in which a CMP processing apparatus is installed. Since it is not necessary to make the cleanness very high and the washing process of the suction table or the like can be simplified, both the equipment cost and the running cost can be reduced. In addition, since the elastic suction plate is detachably provided on the suction table, it can be easily replaced as a consumable when deteriorated, and the required elasticity can always be maintained.

On the other hand, it is also possible to adopt a configuration in which the entire suction table is made of resin. In this case, in addition to the above-mentioned effects, a large elastic force can be obtained on the suction table, so that the dust can be more reliably absorbed in the suction table. There is an advantage that the object to be polished can be prevented from being deformed by sinking into the inside, and the frequency of replacement due to the deterioration of the suction table can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a CMP processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a main part showing a CMP processing apparatus according to a second embodiment of the present invention.

FIG. 3 is a schematic perspective view showing a general CMP processing apparatus.

FIG. 4 is an explanatory diagram of the principle of the CMP processing technique.

FIGS. 5A and 5B are cross-sectional views showing a step of planarizing an interlayer insulating film by a CMP process in a process order, and FIGS. 5A and 5B are cross-sectional views showing a metal wiring forming process by a CMP process in a process order; .

FIG. 6 is a schematic longitudinal sectional view showing a conventional CMP processing apparatus used in a polishing step of a workpiece having a relatively large shape.

FIG. 7 is a perspective view showing an object to be polished after the CMP processing by the same CMP processing apparatus;

[Explanation of symbols]

 3 Polishing Slurry 23 Object to be Polished 23a Surface to be Polished 30 Polishing Pad 37 Suction Table 37a Supporting Surface of Suction Table 38 Elastic Suction Plate 41 Resin Suction Table

Claims (2)

[Claims] 1. A suction table that rotates while adhering and holding an object to be polished to a support surface, and moves while rotating while being pressed against the surface to be polished of the object to be polished, and A polishing pad for performing a CMP process on the surface to be polished through a supplied polishing slurry, wherein an elastic suction plate is detachably attached to a support surface of the suction table. . 2. A resin-made suction table which rotates while adhering and holding an object to be polished to a support surface, and a rotating table which is rotated while being pressed against the surface to be polished of the object to be polished, and A polishing pad for performing a CMP process on the surface to be polished via a polishing slurry supplied therebetween.