WO2025191656A1 - Method for adjusting temperature of member for semiconductor manufacturing device - Google Patents

Abstract

Provided is a method for adjusting the temperature of a member for a semiconductor manufacturing device, the method reducing a local temperature difference in a ceiling portion located on the most upstream side of a ceiling of a refrigerant flow passage to enhance soaking properties of a wafer mounting surface. This method for adjusting the temperature of a member for a semiconductor manufacturing apparatus involves: a step A for heating a ceramic substrate to a predetermined temperature while supplying a refrigerant to a refrigerant flow passage at a predetermined flow rate; a step B for confirming the presence or absence of a local temperature difference in a top surface portion of the ceramic substrate located immediately above a ceiling portion located on the most upstream side of a ceiling of the refrigerant flow passage during performing the step A; and a step C for changing the flow velocity of the refrigerant flowing through the ceiling portion with respect to the flow velocity in the step A so that the local temperature difference decreases, while supplying the refrigerant to the refrigerant flow passage at the same flow rate as that in the step A, and heating the ceramic substrate to the same temperature as that in the step A, when the local temperature difference in the top surface portion is confirmed as a result of the step B.

Description

Temperature control method for semiconductor manufacturing equipment components

The present invention relates to a method for adjusting the temperature of components for semiconductor manufacturing equipment.

Conventionally, semiconductor manufacturing equipment components used for wafer holding, temperature control, transport, etc. have been known. These types of semiconductor manufacturing equipment components are also called wafer mounting tables, electrostatic chucks, susceptors, etc., and generally have the function of applying electrostatic attraction power to built-in electrodes to attract the wafer using electrostatic force. Some are also known to have the function of controlling the wafer temperature by flowing gas between the wafer mounting surface and the wafer to be attracted.

A known example of a semiconductor manufacturing equipment component is one that includes a ceramic substrate with an upper surface and a lower surface on which a wafer can be placed, and which incorporates electrodes, and a base plate located on the underside of the ceramic substrate and which incorporates a coolant flow path. Such semiconductor manufacturing equipment components require a uniform temperature distribution on the wafer-receiving surface to improve the uniform temperature distribution across the wafer. Demands for finer semiconductor circuit wiring are becoming stricter every year, and in response, the requirements for uniform temperature distribution on the wafer-receiving surface of semiconductor manufacturing equipment components are also becoming more stringent.

Japanese Patent Application Laid-Open Publication No. 2023-70861 (Patent Document 1) describes an issue in which the temperature of the refrigerant increases from the inlet to the outlet, but because the cross-sectional shape of the refrigerant flow path is constant from the inlet to the outlet, the wafer tends to cool more easily near the inlet of the refrigerant flow path and less easily near the outlet, resulting in insufficient wafer heating uniformity. To solve this issue, the document proposes making the cross-sectional area of the refrigerant flow path smaller in the most upstream and most downstream portions of the refrigerant flow path in the area that overlaps with the wafer placement surface in a plan view, compared to the most upstream portion.

JP 2023-70861 A

The temperature of the area of the wafer placement surface located directly above the ceiling of the refrigerant flow path that is located most upstream may rise or fall locally. The refrigerant flow path structure described in Patent Document 1 contributes to improving the overall thermal uniformity of the refrigerant flow path, but even if this refrigerant flow path structure is adopted, if such local temperature differences occur, the temperature differences cannot be reduced, and there is room for improvement.

In light of the above circumstances, one embodiment of the present invention aims to provide a temperature adjustment method for semiconductor manufacturing equipment components that reduces local temperature differences in the ceiling portion of the refrigerant flow path that is located most upstream, thereby improving the thermal uniformity of the wafer mounting surface.

The inventors conducted extensive research to solve the above problems and created the present invention, which is exemplified below.

[Aspect 1]
A temperature control method for a semiconductor manufacturing equipment component, comprising:
The semiconductor manufacturing equipment member is
a ceramic substrate having an upper surface on which a wafer can be placed and a lower surface and incorporating an electrode; and a base plate located on the lower surface side of the ceramic substrate and incorporating a coolant flow path,
The temperature adjustment method includes:
a step A of heating the ceramic substrate to a predetermined temperature while supplying a refrigerant to the refrigerant flow path at a predetermined flow rate;
a step B of checking whether or not there is a local temperature difference in an upper surface portion of the ceramic substrate located immediately above a ceiling portion located most upstream of the ceiling of the refrigerant flow path during the step A;
and a step C, in which, when a local temperature difference is confirmed in the upper surface portion as a result of the step B, the flow rate of the refrigerant flowing through the ceiling portion is changed relative to the flow rate in the step A while supplying the refrigerant to the refrigerant flow path at the same flow rate as in the step A so as to reduce the local temperature difference, thereby heating the ceramic substrate to the same temperature as in the step A.
A temperature regulation method including:
[Aspect 2]
In step C, the temperature control method according to aspect 1 further comprises changing an inner cross-sectional area of a refrigerant supply pipe connected to an inlet of the refrigerant flow path so as to change the flow velocity of the refrigerant flowing through the ceiling portion relative to the flow velocity in step A.
[Aspect 3]
A temperature regulating method according to aspect 1 or 2, wherein an inlet of the refrigerant flow path is provided on a lower surface of the base plate, and the ceiling portion is located directly above the inlet.
[Aspect 4]
When a local temperature increase in the upper surface portion is confirmed as a result of step B, in step C, a flow rate of the refrigerant flowing through the ceiling portion is increased relative to the flow rate in step A.
[Aspect 5]
When a local temperature drop in the upper surface portion is confirmed as a result of step B, in step C, the flow rate of the refrigerant flowing through the ceiling portion is reduced relative to the flow rate in step A.
[Aspect 6]
A temperature adjusting method according to any one of aspects 1 to 5, wherein step A involves one or both of passing a current through the electrodes and applying heat to the ceramic substrate from the outside.
[Aspect 7]
Step B involves measuring one or more selected from a temperature distribution on the upper surface of the ceramic substrate, a temperature distribution on a wafer placed on the upper surface of the ceramic substrate, and a distribution of a wafer processing state. The temperature adjustment method according to any one of aspects 1 to 6.
[Aspect 8]
A temperature control method according to any one of aspects 1 to 7, further comprising: a step D of confirming, while performing step C, that a local temperature difference in an upper surface portion of the ceramic substrate located immediately above a ceiling portion located most upstream of the ceiling of the refrigerant flow path has decreased.
[Aspect 9]
A temperature adjustment method according to aspect 8, comprising recording at least the conditions under which step C is performed that have been changed from the conditions under which step A is performed when it is confirmed that the local temperature difference has decreased in step D.
[Aspect 10]
The temperature control method according to any one of Aspects 1 to 9, wherein at least one of the steps A and B is virtually performed using calculations by a simulation program.

The temperature adjustment method for a semiconductor manufacturing equipment component according to one embodiment of the present invention can reduce local temperature differences in the ceiling portion of the refrigerant flow path at the most upstream side, thereby improving the thermal uniformity of the wafer mounting surface. This improves the thermal uniformity within the wafer surface. Furthermore, because this temperature adjustment method can be implemented without modifying the refrigerant flow path inside the semiconductor manufacturing equipment component, it is highly useful as a simple temperature adjustment method for semiconductor manufacturing equipment components.

1 is a longitudinal cross-sectional view of a semiconductor manufacturing equipment member according to one embodiment of the present invention (a cross-sectional view taken along a plane including the central axis of the semiconductor manufacturing equipment member). Schematic diagram of an example of thermography of the central upper surface of a ceramic substrate when there is a local temperature difference in the upper surface portion of the ceramic substrate located directly above the ceiling portion located most upstream of the ceiling of the refrigerant flow path. FIG. 10 is a diagram illustrating how, by changing the inner diameter of the refrigerant supply pipe connected to the inlet of the refrigerant flow path, the initially existing localized high or low temperature areas disappear, resulting in uniform temperature distribution on the top surface of the ceramic substrate. This shows the change in temperature distribution on the top surface of the ceramic substrate as measured by thermography when the flow rate of the coolant supplied to the coolant flow path is changed. This shows the change in temperature distribution on the top surface of the ceramic substrate as measured by thermography when the inner diameter of the refrigerant supply pipe is changed. 1A to 1C are diagrams showing a manufacturing process of a semiconductor manufacturing equipment member according to an embodiment of the present invention.

Next, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and it should be understood that appropriate design changes and improvements may be made based on the common knowledge of those skilled in the art, provided that they do not deviate from the spirit of the present invention. Furthermore, in this specification, "upper" and "lower" are used for convenience to indicate the relative positional relationship when the semiconductor manufacturing equipment component is placed on a horizontal surface with the base plate facing downwards, and do not indicate absolute positional relationships. Therefore, depending on the orientation of the semiconductor manufacturing equipment component, "upper" and "lower" may become "lower" and "upper," "left" and "right," or "front" and "rear."

<1. Configuration of semiconductor manufacturing equipment components>
1 , a semiconductor manufacturing equipment member 10 according to one embodiment of the present invention can be used when performing processes such as CVD and etching on a wafer W using plasma, and can be fixed to a mounting plate 96 provided inside a semiconductor process chamber. The semiconductor manufacturing equipment member 10 includes a ceramic substrate 20 having an upper surface 21 a on which a wafer W can be placed, and a lower surface 23, and incorporating an electrode 26. The semiconductor manufacturing equipment member 10 also includes a base plate 30 located on the lower surface 23 side of the ceramic substrate 20 and incorporating a coolant flow path 32. The ceramic substrate 20 and the base plate 30 can be bonded together by a bonding layer 40.

The ceramic substrate 20 has a central portion 20a having a circular upper surface 21a in a planar view, and an outer peripheral portion 20b having an annular upper surface 21b in a planar view around the central portion 20a. A wafer W can be placed on the upper surface 21a, and a focus ring 78 can be placed on the upper surface 21b. Hereinafter, the focus ring may be abbreviated as "FR." The ceramic substrate 20 is formed from a ceramic material such as alumina or aluminum nitride. The upper surface 21b of the outer peripheral portion 20b is one step lower than the upper surface 21a of the central portion 20a. The central portion 20a and the lower surface 23 of the outer peripheral portion 20b may be on the same plane. The ceramic substrate 20 may have a central portion 20a but no outer peripheral portion 20b, i.e., it may not have the one-step lower upper surface 21b.

In the embodiment shown in FIG. 1, the focus ring 78 and the upper surface of the wafer W are flush with each other, but the upper surface of the focus ring 78 may be located higher than the wafer. In the embodiment shown in FIG. 1, the outer diameter of the focus ring 78 and the outer diameter of the outer periphery 20b of the ceramic substrate 20 are the same, but the outer diameters of the two do not have to be the same.

The upper surface 21a on which the wafer W can be placed may be provided with a plurality of small protrusions (not shown). A seal band (not shown) may also be formed along the outer edge of the upper surface 21a. In this case, the wafer W may be supported by the top surface of the seal band and the top surfaces of the plurality of small protrusions.

The central portion 20a of the ceramic substrate 20 can have a diameter of 190 to 450 mm and a thickness of 1 to 5 mm, for example. Furthermore, the central portion 20a of the ceramic substrate 20 can have an electrode 26 built in on the side closer to the upper surface 21a. The electrode 26 is formed from a material containing, for example, W, Mo, WC, MoC, etc. The electrode 26 can be, for example, a planar electrostatic attraction electrode. When the electrode 26 is an electrostatic attraction electrode, when a DC voltage is applied to the electrode 26, the wafer W is attracted and fixed to the upper surface 21a by electrostatic attraction force, and when the application of the DC voltage is released, the wafer W is released from the attraction and fixation to the upper surface 21a.

A power supply 52 is connected to the electrode 26 via a power supply terminal 54. The power supply terminal 54 is inserted into a terminal hole 51 provided in the vertical direction between the electrode 26 and the underside 33 of the base plate 30. An insulating tube 55 is provided in the portion of the terminal hole 51 that passes through the base plate 30 and the bonding layer 40 in the vertical direction. The power supply terminal 54 passes through the insulating tube 55 provided in the base plate 30 and the bonding layer 40, and further passes through the terminal hole 51 provided in the ceramic substrate 20 to reach the electrode 26. A low-pass filter (LPF) 53 may be provided between the power supply 52 and the electrode 26.

In place of or in addition to the electrostatic attraction electrode, the electrode 26 may incorporate a heater electrode (resistive heating element), or an RF electrode for generating plasma. In this case, a heater power supply is connected to the heater electrode, and an RF power supply is connected to the RF electrode. The ceramic substrate 20 may incorporate one layer of electrode 26, or two or more layers spaced apart. A ring heater may also be installed on the outer periphery 20b of the ceramic substrate 20 (i.e., below the focus ring 78).

The base plate 30 may be disc-shaped and includes a central portion 30a with a circular upper surface 31a in plan view, and a flange portion 30b with an annular upper surface 31b in plan view on the outer periphery of the central portion 30a. The thickness of the central portion 30a may be, for example, 5 to 50 mm. The upper surface 31b of the flange portion 30b is preferably one step lower than the upper surface 31a of the central portion 30a. This allows the clamp used to secure the semiconductor manufacturing equipment member 10 to the installation plate 96 to be kept low (e.g., below the upper surface 31a of the base plate 30). Furthermore, if a ring heater is placed under the focus ring 78, space for the ring heater can be secured. The central portion 30a and the lower surface 33 of the flange portion 30b may be on the same plane.

The base plate 30 can be made of, for example, a metal material or a composite material of metal and ceramic. Examples of metal materials include Al, Ti, Mo, and alloys thereof. Examples of composite materials of metal and ceramic include metal matrix composites (MMCs) and ceramic matrix composites (CMCs). Specific examples of such composite materials include a material containing Si, SiC, and Ti (also known as SiSiCTi), a material in which porous SiC is impregnated with Al and/or Si, and a composite material of _Al2O3 and TiC. A material in which porous _SiC is impregnated with Al is called AlSiC, and a material in which porous SiC is impregnated with Si is called SiSiC. It is preferable to select a material for the base plate 30 that has a thermal expansion coefficient similar to that of the material for the ceramic substrate 20. For example, if the ceramic substrate 20 is made of alumina, the base plate 30 is preferably made of SiSiCTi or AlSiC, which have a thermal expansion coefficient similar to that of alumina.

The base plate 30 can be used as an RF electrode by connecting it to an RF power supply 62 via a power supply terminal 64. A high-pass filter (HPF) 63 can be placed between the base plate 30 and the RF power supply 62. The base plate 30 can have a flange portion 30b on the underside 33 that is used to clamp or bolt the semiconductor manufacturing equipment component 10 to a mounting plate 96. A ring heater (not shown) can also be placed on the flange portion 30b. In this case, the ring heater can be bolted to the mounting plate 96.

The base plate 30 incorporates a refrigerant flow path 32 through which a refrigerant can circulate. In one embodiment, the refrigerant flow path 32 is divided into a central flow path section from the inlet 32a, through which the ceiling 32c closest to the upper surface 31a of the base plate 30 extends, to the outlet 32s; an inlet flow path section 36 from the inlet 36a in the base plate 30 to the inlet 32a of the central flow path section; and an outlet flow path section 38 from the outlet 32s of the central flow path section to the outlet 38a in the base plate 30. The central flow path section is typically a flow path section for flowing refrigerant horizontally from the inlet 32a to the outlet 32s. The inlet of the refrigerant flow path 32 (i.e., the inlet 36a of the inlet flow path section 36) is connected to a refrigerant supply pipe 37. The outlet of the refrigerant flow path 32 (i.e., the outlet 38a of the outlet flow path section 38) is connected to a refrigerant recovery pipe 39. There are no particular limitations on the method for connecting the refrigerant flow path 32 to the refrigerant supply pipe 37 or the refrigerant recovery pipe 39, but examples include a method of connection using pipe connection components such as fittings.

The refrigerant discharged from the outlet 38a of the discharge flow path section 38 passes through the refrigerant recovery pipe 39, where its temperature is adjusted in an external refrigerant device (not shown), before passing through the refrigerant supply pipe 37 and re-entering the refrigerant flow path 32 from the inlet 36a of the intake flow path section 36.

For example, when viewing a cross section of the central flow path portion cut horizontally from above, the central flow path portion can be formed in a single stroke from the inlet 32a to the outlet 32s across the entire area of the base plate 30 excluding the flange portion 30b. As described in JP 2023-70861 A, the central flow path portion of the refrigerant flow path 32 may be formed in a zigzag or spiral shape in plan view to make it easier to route the central flow path across the entire base plate 30. Other shapes are also possible.

The inlet of the refrigerant flow path 32 (i.e., the inlet 36a of the inlet flow path section 36) and the outlet of the refrigerant flow path 32 (i.e., the outlet 38a of the outlet flow path section 38) may be provided on the underside 33 of the base plate 30, as shown in FIG. 1. In one embodiment, the inlet of the refrigerant flow path 32 is located on the underside 33 of the base plate 30, and the ceiling portion 32c1, which is the most upstream portion of the ceiling 32c of the refrigerant flow path 32, is located directly above the inlet. In this case, the inlet flow path section 36 can be formed to extend vertically. By adopting this configuration, local changes in the flow velocity of the refrigerant, such as those caused by changing the internal cross-sectional area of the refrigerant supply pipe 37, are more likely to be reflected in the ceiling portion 32c1, thereby making it easier to achieve temperature regulation effects. The shorter the length of the inlet flow path section 36, the easier it is to achieve temperature regulation effects. For example, the length of the inlet flow path section 36 is preferably 40 mm or less, and more preferably 30 mm or less. However, due to structural constraints of the base plate 30, the length of the inlet channel section 36 is generally 2 mm or more.

In the embodiment shown in FIG. 1, the inlet 36a of the inlet flow passage section 36 and the outlet 38a of the outlet flow passage section 38 are connected to the outermost part of the central flow passage section of the refrigerant flow passage 32, but they may also be connected to other locations (e.g., the center). Furthermore, the inlet 36a of the inlet flow passage section 36 and the outlet 38a of the outlet flow passage section 38 may also be provided on the side of the base plate 30 (including the side of the flange section 30b).

The refrigerant flowing through the refrigerant flow path 32 is preferably a liquid, and is preferably electrically insulating. Examples of electrically insulating liquids include fluorine-based inert liquids.

The internal cross-sectional area of the refrigerant flow path 32 in a cross section perpendicular to the direction of refrigerant flow may be constant from the inlet 32a to the outlet 32s, or may be smaller at the most downstream portion than at the most upstream portion. In this case, the internal cross-sectional area at the inlet 32a is preferably 60 to 90% of the internal cross-sectional area at the outlet 32s. If this ratio is 90% or less, the effect of improving the thermal uniformity of the wafer W is enhanced. Furthermore, if this ratio is 60% or more, the pressure loss does not become too large and the refrigerant can flow at a sufficient flow rate. The flow path cross-sectional area of the refrigerant flow path 32 may decrease continuously or in steps from the inlet 32a to the outlet 32s, but it is preferable that it decrease continuously.

The bonding layer 40 bonds the lower surface 23 of the ceramic substrate 20 to the upper surface 31a of the central portion 30a of the base plate 30. The bonding layer 40 may be composed of a metal layer formed, for example, from solder or metal brazing material. The bonding layer 40 is formed, for example, by TCB (Thermal Compression Bonding). TCB is a well-known method in which a metal bonding material is sandwiched between two components to be joined and the two components are pressure-bonded while heated to a temperature below the solidus temperature of the metal bonding material. The bonding layer 40 is not limited to a metal layer. For example, a resin bonding layer may be used instead of a metal layer. The resin bonding layer may be composed of a cured product of, for example, a silicone resin adhesive, an epoxy resin adhesive, an acrylic resin adhesive, or a urethane resin adhesive.

The side surfaces of the outer peripheral portion 20b of the ceramic substrate 20, the outer periphery of the bonding layer 40, the side surfaces of the base plate 30, and the upper surface 31b and side surfaces of the flange portion 30b can be coated with an insulating film 42. Examples of the insulating film 42 include a thermally sprayed film of alumina, yttria, or the like.

The semiconductor manufacturing equipment component 10 can be fixed to a mounting plate 96 installed inside the chamber using a clamp member 70. The clamp member 70 is an annular member with a generally inverted L-shaped cross section and has an inner stepped surface 70a. In the embodiment shown in FIG. 1, the semiconductor manufacturing equipment component 10 and the mounting plate 96 are integrated by the clamp member 70. With the inner stepped surface 70a of the clamp member 70 placed on the upper surface 31b of the flange portion 30b of the base plate 30, bolts 72 are inserted from the upper surface of the clamp member 70 and screwed into threaded holes provided on the upper surface of the mounting plate 96. The bolts 72 are attached at multiple locations (e.g., 8 or 12 locations) evenly spaced around the circumference of the clamp member 70. The clamp member 70 and bolts 72 may be made of an insulating material or a conductive material (such as a metal). Alternatively, without using the clamp member 70, the semiconductor manufacturing equipment component 10 may be fixed to the mounting plate 96 by inserting bolts 72 from the upper surface 31b of the flange portion 30b of the base plate 30 and screwing them into threaded holes provided on the upper surface of the mounting plate 96. If a ring heater (not shown) is placed on the upper surface 31b of the flange portion 30b, the ring heater can be bolted to the mounting plate 96.

In the above-described embodiment, the semiconductor manufacturing equipment component 10 may have a plurality of holes that penetrate the semiconductor manufacturing equipment component 10 in the vertical direction. Such holes include a plurality of gas holes that open to the upper surface 21a and lift pin holes for inserting lift pins that move the wafer W up and down relative to the upper surface 21a. A plurality of gas holes can be provided at appropriate positions when the upper surface 21a is viewed from above. A thermally conductive gas such as He gas is supplied to the gas holes. Typically, the gas holes can be provided so as to open to locations on the upper surface 21a where the aforementioned seal bands and small protrusions are provided but where no seal bands or small protrusions are provided. When the thermally conductive gas is supplied to the gas holes, the thermally conductive gas fills the space on the back side of the wafer W placed on the upper surface 21a. A plurality of lift pin holes can be provided at equal intervals along concentric circles on the upper surface 21a when the upper surface 21a is viewed from above.

<2. Method of using semiconductor manufacturing equipment components>
Next, an exemplary method for using the semiconductor manufacturing equipment member 10 will be described. First, the semiconductor manufacturing equipment member 10 is fixed to a mounting plate 96 in a chamber (not shown) using the clamp members 70. A focus ring 78 is placed on the upper surface 21b of the semiconductor manufacturing equipment member 10, and a disk-shaped wafer W is placed on the upper surface 21a. The focus ring 78 has a step along the inner periphery of its upper end to prevent interference with the wafer W.

In this state, a voltage is applied to electrode 26 from power supply 52 to adsorb wafer W onto upper surface 21a. A process gas is then supplied from a showerhead (not shown) to create a reactive gas atmosphere at a predetermined pressure (several tens to several hundred Pa) inside the chamber. In this state, a high-frequency voltage such as an RF voltage is applied between an upper electrode (not shown) located on the ceiling of the chamber and base plate 30 of semiconductor manufacturing equipment member 10. This generates plasma between wafer W and the showerhead. This plasma is then used to process wafer W (by CVD deposition or etching). Note that as wafer W is plasma-processed, focus ring 78 also wears out. However, because focus ring 78 is thicker than wafer W, focus ring 78 is replaced after processing multiple wafers W.

A refrigerant circulates through the refrigerant flow path 32 of the base plate 30. The flow rate of the refrigerant supplied to the refrigerant flow path 32 is not limited, but is preferably 10 to 30 L/min, and more preferably 20 to 30 L/min. The refrigerant flow path 32 is connected to the supply port and recovery port of an external refrigerant device (not shown) via a refrigerant supply pipe 37 and a refrigerant recovery pipe 39. The refrigerant introduced into the refrigerant flow path 32 from the supply port of the external refrigerant device via the refrigerant supply pipe 37 passes through the refrigerant flow path 32, returns to the recovery port of the external refrigerant device via the refrigerant recovery pipe 39, and is temperature-adjusted. The refrigerant is then supplied again to the refrigerant flow path 32 from the supply port of the external refrigerant device via the refrigerant supply pipe 37.

<3. Temperature Control Method for Semiconductor Manufacturing Equipment Components>
According to one embodiment of the present invention, a method for adjusting the temperature of a semiconductor manufacturing equipment component 10 is provided.
In one embodiment, the temperature adjustment method includes:
a step A of heating the ceramic substrate 20 to a predetermined temperature while supplying a refrigerant to the refrigerant flow path 32 at a predetermined flow rate;
a step B of checking whether or not there is a local temperature difference in the upper surface portion of the ceramic substrate 20 located immediately above the ceiling portion 32c1 located most upstream of the ceiling 32c of the refrigerant flow path 32 while the step A is being performed;
If a local temperature difference is confirmed in the upper surface portion as a result of the process B, a process C is carried out in which the flow rate of the refrigerant flowing through the ceiling portion 32c1 is changed from the flow rate in the process A so as to reduce the local temperature difference while supplying the refrigerant to the refrigerant flow path 32 at the same flow rate as in the process A, thereby heating the ceramic substrate 20 to the same temperature as in the process A.
Includes.

In process A, the ceramic substrate 20 is heated to a predetermined temperature (e.g., 60-100°C) while a refrigerant is supplied to the refrigerant flow path 32 at a predetermined flow rate. Process A can be performed, for example, during pre-shipment inspection of the semiconductor manufacturing equipment component 10, during trial operation after the semiconductor manufacturing equipment component 10 has been installed in the semiconductor manufacturing equipment, or during mass production of semiconductors after the semiconductor manufacturing equipment component 10 has been installed in the semiconductor manufacturing equipment. Process A can be performed without placing a wafer W on the upper surface 21a of the semiconductor manufacturing equipment component 10, or while placing a wafer W on the upper surface 21a of the semiconductor manufacturing equipment component 10 and processing it with plasma. Process A can be performed actually, or virtually using calculations by a simulation program.

The flow rate of the coolant supplied to the coolant flow path 32 can be controlled to a predetermined amount by a flow control device such as a metering pump or a flow control valve. Methods for heating the ceramic substrate 20 include, for example, heating by Joule heat generated by passing current through the electrode 26 (heater electrode) or a heater electrode separately provided on the ceramic substrate 20, and heat input from outside the semiconductor manufacturing equipment component 10 (e.g., heating by plasma). Therefore, in one embodiment, step A involves one or both of passing current through the electrode 26 and applying heat to the ceramic substrate 20 from outside. Plasma can be generated, for example, by applying a high-frequency voltage such as an RF voltage between an upper electrode (not shown) provided on the ceiling of the chamber and the base plate 30 of the semiconductor manufacturing equipment component 10.

In process B, while process A is being performed, the presence or absence of a local temperature difference is confirmed on the upper surface portion of the ceramic substrate 20 located directly above the ceiling portion 32c1 located most upstream of the ceiling 32c of the refrigerant flow path 32. One method for confirming the presence or absence of a local temperature difference is, for example, to photograph the upper surface 21a of the ceramic substrate 20 or the surface of the wafer W with a thermographic camera, measure the heat distribution on the upper surface 21a, and compare the upper surface portion of the ceramic substrate 20 located directly above the ceiling portion 32c1 with the other upper surface portions of the ceramic substrate 20 to confirm the presence or absence of a local temperature difference. Another method for confirming the presence or absence of a local temperature difference is to measure the distribution of the wafer processing state, such as the etching rate. Therefore, in one embodiment, process B involves measuring one or more selected from the temperature distribution on the upper surface 21a of the ceramic substrate 20, the temperature distribution of the wafer W placed on the upper surface 21a of the ceramic substrate 20, and the distribution of the wafer processing state. Process B may be performed actually or virtually using calculations with a simulation program.

Figure 2 shows a schematic example of a thermography image of the upper surface 21a of the ceramic substrate 20 when there is a local temperature difference in the upper surface portion of the ceramic substrate 20 located directly above the ceiling portion 32c1 located most upstream of the ceiling 32c of the refrigerant flow path 32. A local temperature difference occurs, for example, when there is a localized area that is 1°C or more higher or lower than the average temperature of the upper surface 21a of the ceramic substrate 20. Such localized temperature abnormalities are likely to occur when the refrigerant flow rate differs from the target.

In process C, if a local temperature difference is confirmed in the upper surface portion as a result of process B, the flow rate of the refrigerant flowing through ceiling portion 32c1 is changed relative to the flow rate in process A so as to reduce the local temperature difference, and the refrigerant is supplied to the refrigerant flow path 32 at the same flow rate as in process A, while heating the ceramic substrate 20 to the same temperature as in process A. For example, if a local temperature increase is confirmed in the upper surface portion as a result of process B, the flow rate of the refrigerant flowing through ceiling portion 32c1 can be increased in process C relative to the flow rate in process A. Furthermore, if a local temperature decrease is confirmed in the upper surface portion as a result of process B, the flow rate of the refrigerant flowing through ceiling portion 32c1 can be decreased in process C relative to the flow rate in process A.

One method for changing the flow rate of the refrigerant flowing through ceiling portion 32c1 relative to the flow rate in process A is to change the internal cross-sectional area of refrigerant supply pipe 37 connected to the inlet of refrigerant flow path 32 (i.e., inlet 36a of introduction flow path portion 36) from that in process A. If the internal cross-sectional areas of introduction flow path portion 36 of refrigerant flow path 32 and refrigerant supply pipe 37 are different, a connecting part 35 for a different diameter pipe, such as a different diameter joint, can be used to connect refrigerant supply pipe 37 and introduction flow path portion 36. Figure 3 illustrates how changing the internal cross-sectional area of refrigerant supply pipe 37 connected to the inlet of refrigerant flow path 32 (i.e., inlet 36a of introduction flow path portion 36) eliminates the localized high or low temperature areas that were initially present, resulting in uniform heating of upper surface 21a of ceramic substrate 20.

There are no particular limitations on the length of the piping that changes the internal cross-sectional area of the refrigerant supply piping 37. The refrigerant supply piping 37 extends from the supply port of the external refrigerant device to the inlet of the refrigerant flow path 32. However, the internal cross-sectional area of the refrigerant supply piping 37 does not need to change over the entire length of this distance; it is sufficient to change the internal cross-sectional area of the refrigerant supply piping 37 over a length of piping sufficient to achieve a temperature adjustment effect. For example, it is preferable that the internal cross-sectional area of the refrigerant supply piping 37 changes over a certain length of piping, for example, 3 mm or more, preferably 5 mm or more, from the connection point with the inlet of the refrigerant flow path 32, i.e., the outlet of the refrigerant supply piping 37 (the connection point with the inlet 36a of the introduction flow path section 36) toward the supply port of the external refrigerant device (in other words, toward the upstream side of the refrigerant). Furthermore, because longer piping lengths require more effort to switch the refrigerant supply piping 37, the piping length that changes the internal cross-sectional area of the refrigerant supply piping 37 is preferably 40 mm or less, and more preferably 30 mm or less. Therefore, it is preferable to vary the internal cross-sectional area of the refrigerant supply pipe 37 over a piping length of 3 to 40 mm from the outlet of the refrigerant supply pipe 37 toward the supply port of the external refrigerant device, and it is even more preferable to vary the internal cross-sectional area of the refrigerant supply pipe 37 over a piping length of 5 to 30 mm.

One possible method for reducing the local temperature difference in the upper surface portion is to change the flow rate of the refrigerant supplied to the refrigerant flow path 32. However, simulations using CAE (Computer Aided Engineering) have confirmed that changing the refrigerant supply flow rate does not have much effect on reducing the local temperature difference. The test procedure, conducted through simulations using ANSYS Workbench (software) manufactured by ANSYS Japan, Inc., is described below. A semiconductor manufacturing equipment component with the structure shown in Figure 1 was prepared. A 10°C coolant was flowed through the refrigerant flow path while heating the ceramic substrate to 80°C by passing an electric current through the electrodes of this semiconductor manufacturing equipment component. The flow rate of the coolant supplied to the refrigerant flow path via a refrigerant supply pipe with an internal cross-sectional area of 16 mm was changed using a flow control device, and the change in temperature distribution on the upper surface of the center of the ceramic substrate was investigated using thermography. Figure 4(A) shows the results when the coolant supply flow rate was set to 30 L/min, and Figure 4(B) shows the results when the coolant supply flow rate was subsequently changed to 15 L/min. The temperature of the upper surface of the ceramic substrate located directly above the ceiling located at the most upstream side of the coolant flow path changed by less than 1°C even when the coolant flow rate was halved.

On the other hand, Figure 5 shows the simulation results for a semiconductor manufacturing equipment component having the structure shown in Figure 1, where the inner cross-sectional area was changed by varying the inner diameter of the refrigerant supply pipe without changing the refrigerant supply flow rate. The test procedure performed through the simulation is explained below. A ceramic substrate was heated to 80°C by passing an electric current through the electrodes of the semiconductor manufacturing equipment component, while a 10°C coolant was flowed through the refrigerant flow path. The flow rate of the coolant supplied to the refrigerant flow path via the refrigerant supply pipe was kept constant at 30 L/min, and the change in temperature distribution on the top surface of the ceramic substrate was investigated using thermography when the inner diameter of the refrigerant supply pipe was changed. Figure 5(A) shows the results when the inner diameter of the refrigerant supply pipe 37 was set to 16 mm over a 100 mm length from the outlet of the refrigerant supply pipe 37 toward the upstream side of the refrigerant. Figure 5(B) shows the results when the inner diameter of the refrigerant supply pipe 37 was then changed to 10 mm over a 100 mm length from the outlet of the refrigerant supply pipe 37 toward the upstream side of the refrigerant. In this case, the temperature of the upper surface of the ceramic substrate located directly above the ceiling of the refrigerant flow path located most upstream dropped by approximately 3°C. This was because the narrowing of the inner diameter of the refrigerant supply pipe increased the refrigerant flow rate, resulting in a localized increase in the flow rate at the ceiling located most upstream of the refrigerant flow path.

The degree to which the flow rate of the refrigerant flowing through ceiling portion 32c1 is changed relative to the flow rate in process A can be set appropriately depending on the degree of thermal uniformity required on upper surface 21a of ceramic substrate 20. However, it is preferable to change the temperature so that there are no localized areas on the upper surface of ceramic substrate 20 that are 1°C or more higher or lower than the average temperature of upper surface 21a, and it is more preferable to change the temperature so that there are no localized areas that are 0.5°C or more higher or lower. As mentioned above, the inlet of refrigerant flow path 32 can be located on the lower surface 33 of base plate 30. If ceiling portion 32c1, the most upstream portion of ceiling 32c of refrigerant flow path 32, is configured to be located directly above the inlet, local changes in refrigerant flow rate are more likely to be reflected in the vicinity of ceiling portion 32c1, thereby making it easier to achieve temperature adjustment effects.

In process C, the ceramic substrate 20 is heated to the same temperature as in process A while supplying the refrigerant to the refrigerant flow path 32 at the same flow rate as in process A. This is done to reproduce process conditions as similar to process A as possible. This is because it is important that local temperature differences are reduced when operating the semiconductor manufacturing equipment under the same process conditions. However, the concept of "same" here also includes "substantially the same." "Substantially the same" includes, for example, cases where the refrigerant flow rate in process C is within ±5% of the refrigerant flow rate in process A, and preferably within ±3%. Also, it includes cases where the heating temperature (°C) of the ceramic substrate in process C is within ±5°C of the heating temperature (°C) of the ceramic substrate in process A, and preferably within ±3°C. Furthermore, it is preferable to use the same heating method in process C to heat the ceramic substrate 20.

While carrying out step C, it is preferable to carry out step D, in which it is confirmed that the local temperature difference in the upper surface portion of the ceramic substrate 20 located directly above the ceiling portion 32c1 located most upstream of the ceiling 32c of the refrigerant flow path 32 has decreased. The same method as the method for confirming the presence or absence of a local temperature difference in step B can be used to confirm that the local temperature difference has decreased compared to the temperature difference confirmed in step B. It is sufficient to confirm that the local temperature difference in the upper surface portion of the ceramic substrate 20 has decreased compared to the local temperature difference confirmed in step B.

When it is confirmed that the local temperature difference has decreased in step D, it is preferable to record at least the conditions under which step C was performed that were changed from the conditions under which step A was performed, such as the changed pipe diameter and pipe length. It is also preferable to record the same conditions as in step C, such as the heating conditions and refrigerant supply conditions in step A, in order to reproduce the preferred process conditions. These conditions can be recorded, for example, in a computer storage device, a readable recording medium, etc.

<4. Manufacturing examples of semiconductor manufacturing equipment components>
Next, a manufacturing example of the semiconductor manufacturing equipment component 10 will be described with reference to FIG. 6 . FIG. 6 is a manufacturing process diagram for the semiconductor manufacturing equipment component 10. First, a disk-shaped ceramic sintered body 120, which will be the basis for the ceramic substrate 20, is fabricated by hot-pressing and firing a ceramic powder compact ( FIG. 6A ). The compact may be fabricated by stacking multiple tape compacts, by mold casting, or by compressing ceramic powder. The ceramic sintered body 120 incorporates an electrode 26. The electrode 26 may be a single layer, or two or more layers spaced apart. Next, an upper terminal hole 151a is formed between the bottom surface of the ceramic sintered body 120 and the electrode 26 ( FIG. 6B ). A power supply terminal 54 is inserted into the upper terminal hole 151a to bond the power supply terminal 54 to the electrode 26 ( FIG. 6C ).

In parallel with this, two disk members 131 and 136 are fabricated (Figure 6D). As mentioned above, the disk members 131 and 136 can be constructed from a metal material (such as Al) or a composite material of metal and ceramics. However, here we will explain the case where the disk members 131 and 136 are made of MMC. Then, vertically penetrating holes are drilled in both MMC disk members 131 and 136, and a groove 132 that will ultimately become the refrigerant flow path 32 is formed on the underside of the upper MMC disk member 131 (Figure 6E). Specifically, an intermediate terminal hole 151b is drilled in the upper MMC disk member 131, and the groove 132 is formed by machining. Furthermore, a lower terminal hole 151c, a through-hole 133 for introducing refrigerant, and a through-hole 134 for discharging refrigerant are drilled in the lower MMC disk member 136. If the ceramic sintered body 120 is made of alumina, it is preferable that the MMC disk members 131, 136 be made of SiSiCTi or AlSiC. This is because the thermal expansion coefficient of alumina is roughly the same as that of SiSiCTi or AlSiC.

A SiSiCTi disk member can be produced, for example, as follows: First, silicon carbide, metallic Si, and metallic Ti are mixed to produce a powder mixture. Next, the resulting powder mixture is uniaxially pressed to produce a disk-shaped compact, which is then hot-press sintered in an inert atmosphere to obtain the SiSiCTi disk member.

Next, a metal bonding material is placed between the lower surface of the upper MMC disc member 131 and the upper surface of the lower MMC disc member 136, and a metal bonding material is also placed on the upper surface of the upper MMC disc member 131. Each metal bonding material has a through hole formed in a position opposite the corresponding hole. The power supply terminal 54 of the ceramic sintered body 120 is then inserted into the middle terminal hole 151b and the lower terminal hole 151c, and the ceramic sintered body 120 is placed on the metal bonding material placed on the upper surface of the upper MMC disc member 131. This results in a laminate in which the lower MMC disc member 136, the metal bonding material, the upper MMC disc member 131, the metal bonding material, and the ceramic sintered body 120 are stacked in this order from bottom to top. This laminate is then heated and pressurized (TCB) to obtain the bonded body 110 (Figure 6F). The bonded body 110 is formed by bonding a ceramic sintered body 120 to the upper surface of an MMC block 130, which is the base of the base plate 30, via a bonding layer 40. The MMC block 130 is formed by bonding an upper MMC disc member 131 to a lower MMC disc member 136 via a bonding layer 135. The MMC block 130 has a refrigerant flow path 32, an inlet flow path section 36, an outlet flow path section 38, and a terminal hole 51. The terminal hole 51 is a hole connecting an upper terminal hole 151a, a middle terminal hole 151b, and a lower terminal hole 151c.

TCB is performed, for example, as follows: The laminate is pressed and bonded at a temperature below the solidus temperature of the metal bonding material (for example, a temperature 20°C below the solidus temperature but below the solidus temperature), and then returned to room temperature. This causes the metal bonding material to become a metal bonding layer. An Al-Mg or Al-Si-Mg bonding material can be used as the metal bonding material in this case. For example, when TCB is performed using an Al-Si-Mg bonding material, the laminate is pressed while heated in a vacuum atmosphere. It is preferable to use a metal bonding material with a thickness of around 100 μm.

Next, the outer periphery of the ceramic sintered body 120 is cut to form a step, resulting in a ceramic substrate 20 with a central portion 20a and an outer periphery 20b. The outer periphery of the MMC block 130 is cut to form a step, resulting in a base plate 30 with a central portion 30a and a flange portion 30b. An insulating tube 55, through which a power supply terminal 54 passes, is placed in the terminal hole 51 from the underside 23 of the ceramic substrate 20 to the underside 33 of the base plate 30. Furthermore, an insulating film 42 is formed by thermally spraying ceramic powder on the side of the outer periphery 20b of the ceramic substrate 20, the periphery of the bonding layer 40, the side of the base plate 30, and the upper surface 31b and side of the flange portion 30b (Figure 6G). This completes the semiconductor manufacturing equipment component 10.

Note that while the base plate 30 in Figure 1 is shown as a single unit, it may instead be a structure in which two components are joined with a metal joining layer, as shown in Figure 6G, or a structure in which three or more components are joined with a metal joining layer.

10: member for semiconductor manufacturing apparatus 20: ceramic substrate 20a: central portion 20b: peripheral portion 21a: upper surface 21b: upper surface 23: lower surface 26: electrode 30: base plate 30a: central portion 30b: flange portion 31a: upper surface 31b: upper surface 32: refrigerant flow path 32a: inlet 32c: ceiling 32c1: ceiling portion 32s located most upstream: outlet 33: lower surface 35: connecting part 36: introduction flow path portion 36a: inlet 37: refrigerant supply piping 38: discharge flow path portion 38a: outlet 39: refrigerant recovery piping 40: bonding layer 42: insulating film 51: terminal hole 52: power source 53: low-pass filter 54: power supply terminal 55: insulating tube 62: RF power source 63: high-pass filter 64: power supply terminal 70 : Clamp member 70a : Inner peripheral step surface 72 : Bolt 78 : Focus ring 96 : Mounting plate 110 : Bonded body 120 : Sintered ceramic body 130 : MMC block 131 : Disk member 132 : Groove 133 : Through hole 134 : Through hole 135 : Bonding layer 136 : Disk member 151a : Upper terminal hole 151b : Middle terminal hole 151c : Lower terminal hole W : Wafer

Claims (10)

A temperature control method for a semiconductor manufacturing equipment component, comprising:
The semiconductor manufacturing equipment member is
a ceramic substrate having an upper surface on which a wafer can be placed and a lower surface and incorporating an electrode; and a base plate located on the lower surface side of the ceramic substrate and incorporating a coolant flow path,
The temperature adjustment method includes:
a step A of heating the ceramic substrate to a predetermined temperature while supplying a refrigerant to the refrigerant flow path at a predetermined flow rate;
a step B of checking whether or not there is a local temperature difference in an upper surface portion of the ceramic substrate located immediately above a ceiling portion located most upstream of the ceiling of the refrigerant flow path during the step A;
and a step C, in which, when a local temperature difference is confirmed in the upper surface portion as a result of the step B, the flow rate of the refrigerant flowing through the ceiling portion is changed relative to the flow rate in the step A while supplying the refrigerant to the refrigerant flow path at the same flow rate as in the step A so as to reduce the local temperature difference, thereby heating the ceramic substrate to the same temperature as in the step A.
A temperature regulation method including: The temperature adjustment method of claim 1, further comprising changing the internal cross-sectional area of the refrigerant supply pipe connected to the inlet of the refrigerant flow path in step C to change the flow rate of the refrigerant flowing through the ceiling portion relative to the flow rate in step A. The temperature adjustment method described in claim 1 or 2, wherein the inlet of the refrigerant flow path is installed on the underside of the base plate, and the ceiling portion is located directly above the inlet. The temperature adjustment method described in claim 1 or 2, further comprising, in step C, increasing the flow rate of the refrigerant flowing through the ceiling portion relative to the flow rate in step A, if a local temperature increase in the upper surface portion is confirmed as a result of step B. The temperature adjustment method of claim 1 or 2, further comprising, in step C, slowing the flow rate of the refrigerant flowing through the ceiling portion relative to the flow rate in step A, if a local temperature drop in the upper surface portion is confirmed as a result of step B. The temperature adjustment method described in claim 1 or 2, wherein step A involves one or both of passing a current through the electrodes and applying heat from the outside to the ceramic substrate. The temperature adjustment method described in claim 1 or 2, wherein step B involves measuring one or more selected from the temperature distribution on the upper surface of the ceramic substrate, the temperature distribution of a wafer placed on the upper surface of the ceramic substrate, and the distribution of the wafer processing state. The temperature adjustment method described in claim 1 or 2 further includes step D, during which step C, confirming that the local temperature difference in the upper surface portion of the ceramic substrate located directly above the ceiling portion located most upstream of the ceiling of the refrigerant flow path has decreased. The temperature adjustment method described in claim 8, further comprising recording at least the conditions under which step C is performed that have been changed from the conditions under which step A is performed when it is confirmed that the local temperature difference has decreased in step D. The temperature adjustment method described in claim 1 or 2, wherein at least one of steps A and B is performed virtually using calculations by a simulation program.