Holding device

Abstract

This technology provides an improvement in the uniformity of temperature distribution within the mounting surface. [Solution] A holding device comprising a plate-shaped member having a mounting surface on which an object is placed, and having a flow path formed inside through which a refrigerant flows, wherein in the cross-section of the plate-shaped member at the position where the flow path is formed, the flow path includes a wide curved section in which the flow path is curved by 90 degrees or more, while containing a wide section in which the flow path is wider, and the width of the flow path in the wide section is wider than the width of the flow path at one end of the wide curved section and the width of the flow path at the other end of the wide curved section.

Description

Technical Field

[0001] The present invention relates to a holding device.

Background Art

[0002] Conventionally, a holding device including a plate-like member having a placement surface on which an object is placed and a flow path through which a refrigerant flows has been known (for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in holding devices such as Patent Documents 1 and 2, there is still room for improvement in the technology for improving the uniformity of the temperature distribution within the placement surface.

[0005] The present invention has been made to solve at least a part of the above-described problems, and an object thereof is to provide a technology for improving the uniformity of the temperature distribution within the placement surface.

Means for Solving the Problems

[0006] The present invention has been made to solve at least a part of the above-described problems, and can be realized in the following forms.

[0007] (1) According to one embodiment of the present invention, a holding device is provided. The holding device comprises a plate-shaped member having a mounting surface on which an object is placed and having a flow path formed inside through which a refrigerant flows, wherein in a cross-section of the plate-shaped member at the position where the flow path is formed, the flow path includes a wide curved section in which the flow path is curved by 90 degrees or more, while encompassing a wide section in which the width of the flow path is wider, and the width of the flow path in the wide section is wider than the width of the flow path at one end of the wide curved section and the width of the flow path at the other end of the wide curved section.

[0008] With this configuration, since the wide curved section included in the flow path through which the refrigerant flows contains a wide section within it, the generation of turbulence in the wide curved section can be suppressed. As a result, the cooling effect caused by turbulence in the wide curved section is mitigated, thereby improving the uniformity of the temperature distribution within the mounting surface on which the object is placed.

[0009] Furthermore, the present invention can be realized in various forms, for example, in the form of a method for manufacturing a holding device, a system including a holding device, a method for controlling these devices and systems, a computer program for causing these devices and systems to process objects, a server device for distributing the computer program, a non-temporary storage medium storing the computer program, and so on. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view of the holding device of the embodiment. [Figure 2] This is a first cross-sectional view of the holding device. [Figure 3] This is a second cross-sectional view of the holding device. [Figure 4] This is an enlarged view of an example of a wide, curved section. [Figure 5] This is an explanatory diagram of the angle formed by two tangent lines. [Figure 6] This is an enlarged view of an example of a wide, curved section. [Figure 7] This is an explanatory diagram showing a comparative example of a joint. [Figure 8] This is an enlarged view of one example of an isolated curved section. [Figure 9] This is an enlarged view of one example of an isolated curved section. [Modes for carrying out the invention]

[0011] <First Embodiment> Figure 1 is a perspective view of the holding device 1 of this embodiment. Figure 2 is a first cross-sectional view of the holding device 1 of this embodiment. The holding device 1 of this embodiment is an electrostatic chuck that holds a substrate W by electrostatic attraction. The electrostatic chuck is used, for example, as a table on which to place the substrate W in an etching process using plasma in a chamber equipped with the electrostatic chuck. The holding device 1 of this embodiment comprises a base 10, a ceramic substrate 20, and a joint (not shown). In the holding device 1, as shown in Figure 1, the base 10 and the ceramic substrate 20 are stacked in that order. The holding device 1 positions the substrate W relative to the holding device 1 by using a focus ring FR installed on the outer circumference of the ceramic substrate 20. In Figures 1 and 2, for convenience, the stacking direction of the base 10 and the ceramic substrate 20 is shown as the z-axis direction, the direction perpendicular to the z-axis is shown as the x-axis direction, and the direction perpendicular to the z-axis and x-axis is shown as the y-axis direction. For the sake of explanation, the relative sizes of the base 10, ceramic substrate 20, substrate W, and focus ring FR shown in Figures 1 and 2 do not reflect the actual relationships.

[0012] The base 10 is a sintered body mainly composed of silicon carbide (SiC), and is a roughly cylindrical member that forms the base of the holding device 1. Here, "main component" means the component with the highest proportion. The material forming the base 10 is not limited to a material mainly composed of silicon carbide. The base 10 may be formed from materials such as aluminum (Al), titanium (Ti), molybdenum (Mo), tungsten (W), alloys thereof, SUS, composites of metals and ceramics such as Al-SiC, or materials mainly composed of ceramics such as aluminum nitride (AlN) or alumina (Al2O3).

[0013] The base 10 comprises a first base 11 and a second base 12. The first base 11 and the second base 12 are joined together by an adhesive layer (not shown). The base 10 is not limited to a two-layer structure like the first base 11 and the second base 12; it may also be a single-layer structure or a structure consisting of three or more layers.

[0014] As shown in Figure 2, the first base 11 is located on the most negative side in the z-axis direction in the holding device 1. The first base 11 is a substantially circular plate-like member and has a pair of main surfaces 11a and 11b. The second base 12 is stacked on the first base 11 on the positive side in the z-axis direction of the first base 11. The second base 12 is a substantially circular plate-like member of approximately the same size as the first base 11 and has a pair of main surfaces 12a and 12b. Of the pair of main surfaces 12a and 12b of the second base 12, a groove 13 is formed on the main surface 12b on the negative side in the z-axis direction, which serves as a flow path 30 through which the refrigerant flows. When the first base 11 and the second base 12 are joined together, the groove 13 formed in the second base 12 becomes a flow path 30 when the first base 11 acts as a cover for the groove 13. The base 10 has a plurality of holes 14 formed along the z-axis direction of the holding device 1. The detailed shape of the flow path 30 will be described later.

[0015] The ceramic substrate 20 is a plate-shaped member disposed on the plus side in the z-axis direction of the base 10. The ceramic substrate 20 is mainly composed of ceramics. The ceramic substrate 20 of the present embodiment is formed of a material mainly composed of aluminum oxide. Note that the ceramic substrate 20 may be formed of other ceramics such as aluminum nitride and silicon carbide. The ceramic substrate 20 has a pair of main surfaces 20a and 20b.

[0016] On one main surface 20a of the pair of main surfaces 20a and 20b of the ceramic substrate 20, which is opposite to the base 10, a mounting surface 21 on which the substrate W is placed is formed. On the outer periphery of one main surface 20a of the ceramic substrate 20, a focus ring mounting surface 22 on which the focus ring FR is placed is formed. The other main surface 20b of the pair of main surfaces 20a and 20b of the ceramic substrate 20 is joined to the second base 12 by a joint portion not shown. In the ceramic substrate 20, holes 23 communicating with each of the plurality of holes 14 formed in the base 10 are formed. Examples of the method of joining the base 10 and the ceramic substrate 20 include, but are not limited to, metal joining, resin joining, and joining with an inorganic material.

[0017] The ceramic substrate 20 of the present embodiment has an electrode 24. The electrode 24 is disposed inside the ceramic substrate 20. The electrode 24 is formed of a conductive material such as tungsten or molybdenum, for example. The electrode 24 is connected to an external power supply via electrode terminals (not shown) inserted through the holes 14 and 23. Examples of the electrode 24 include a high-frequency electrode, a chuck electrode, and a heater electrode.

[0018] The holding device 1 of the present embodiment has a hole 5a that penetrates a joined body 5 composed of a base 10 and a ceramic substrate 20 in the z-axis direction, by means of a hole 14 formed in the base 10 and a hole 23 formed in the ceramic substrate 20. The hole 5a of the joined body 5 serves as a terminal hole for inserting a power supply terminal (not shown) for supplying power to the electrode 24 of the ceramic substrate 20, a gas hole for supplying helium gas to the back surface of the substrate W, a lift pin hole for inserting a lift pin (not shown) for lifting the substrate W from the ceramic substrate 20, a sensor hole for inserting a temperature sensor (not shown) for measuring the temperature of the mounting surface 21, and the like. Note that, although the hole 5a of the joined body 5 of the present embodiment penetrates the joined body 5 in the z-axis direction, it may not penetrate the joined body 5. Specifically, the hole 5a may have a configuration that combines, for example, a hole 14 that penetrates the base 10 and a hole having the other main surface 20b of the ceramic substrate 20 or a bottom surface formed on the other main surface 20b. In this case, the other main surface 20b of the ceramic substrate 20 or the bottom surface formed on the other main surface 20b serves as the bottom surface of the hole 5a. Also, the hole 14 may be a non-penetrating hole having a bottom surface.

[0019] The joined body 5 corresponds to the "plate-like member" in the claims. That is, the joined body 5 has a mounting surface 21 on which the substrate W, which is the object, is placed, and is a plate-like member in which a flow path 30 through which a refrigerant flows is formed inside.

[0020] FIG. 3 is a second cross-sectional view of the holding device 1. FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2. FIG. 3 shows a cross-section of the joined body 5 at the position where the groove 13 (flow path 30) is formed. As shown in FIG. 3, the flow path 30 is formed in a substantially spiral shape. The flow path 30 includes a flow path inlet IN through which the refrigerant flows into the flow path 30 and a flow path outlet OUT from which the refrigerant flows out of the flow path 30. The shape of the flow path inlet IN and the shape of the flow path outlet OUT in the cross-section are circular. Also, the flow path 30 may include a plurality of branch and confluence portions where the flow path 30 branches into two flow paths and those flow paths merge into one flow path.

[0021] The flow path 30 includes a flow path inlet IN, a flow path outlet OUT, as well as a wide curved section and an isolated curved section. Of these two sections, the wide curved section will be described first. Section WC1, shown in hatching in Figure 3, is an example of a wide curved section. In the cross-section shown in Figure 3, the wide curved section is a section in which the flow path 30 is curved by 90 degrees or more, while encompassing a wide section (exemplified as wide section WD in Figure 4). In this embodiment, the length of the wide curved section is 10% or less of the total length of the flow path 30 in the cross-section shown in Figure 3. That is, the length of section WC1 is 10% or less of the total length of the flow path 30. Details of section SC1 shown in Figure 3 will be explained later using Figure 8.

[0022] Figure 4 is an enlarged view of section WC1, which was shown in Figure 3 as an example of a wide curved section. Figure 4 shows the center line Lw, one end Ew1, and the other end Ew2. The center line Lw is the center line of the channel 30 within the wide curved section. That is, the center line Lw is the bisector of the width of the channel 30 at each position within the wide curved section. One end Ew1 and the other end Ew2 are the one end and the other end of the wide curved section.

[0023] Using Figure 4, we will explain the two requirements that a section considered to be a wide curved section must satisfy. First, let's explain the first requirement. In section WC1, the angle between the tangent Tw1 to the center line Lw at one end Ew1 and the tangent Tw2 to the center line Lw at the other end Ew2 is 90 degrees or more. Figure 5 shows the angle α between the tangents Tw1 and Tw2 shown in Figure 4. Since angle α indicates the degree of curvature of the flow path 30 in section WC1, section WC1 is a section in which the flow path 30 is curved by 90 degrees or more. Thus, a section of the flow path 30 that is considered a wide curved section satisfies the requirement that the flow path 30 is curved by 90 degrees or more (a curved section).

[0024] Next, let's explain the second requirement. In Figure 4, the width of the channel 30 in the wide section WD, indicated by dense hatching, is wider than both the width Ws1 of the channel 30 at one end Ew1 and the width Ws2 of the channel 30 at the other end Ew2. Here, the width of the channel 30 refers to the length of the channel 30 in the direction perpendicular to the tangent at each position of the center line Lw. Section WC1 contains such a wide section WD. Thus, the section of the channel 30 that is considered a wide curved section satisfies both requirements: it is a curved section and it contains a wide section.

[0025] Figure 6 shows section WC2 included in the flow path 30. It explains that section WC2 is a wide curved section different from section WC1 shown in Figure 3. Among the sections included in the flow path 30, any section whose length is 10% or less of the total length of the flow path 30 and that satisfies the two requirements mentioned above is considered a wide curved section included in the flow path 30. For example, although section WC2 (shown in Figure 6) is a section of different length from section WC1 (shown in Figure 3), it satisfies the two requirements mentioned above and is therefore considered a wide curved section, just like section WC1. In this way, the flow path 30 contains countless wide curved sections with different locations and lengths.

[0026] The positions of the channel inlet IN and channel outlet OUT are determined by their positional relationship with other components in the chamber, so it may be necessary to provide a curved section (a section in which the channel 30 is curved by 90 degrees or more) in the channel 30. In this case, the temperature distribution of the portion of the mounting surface 21 (see Figures 1 and 2) on which the substrate W is placed that corresponds to the curved section may be lower than that of the surrounding portion. Figure 7 is an explanatory diagram showing the joint 5c of the comparative example. The channel 30c formed in the joint 5c of the comparative example differs from the channel 30 only in that the shape of the portion corresponding to section WC1 (see Figure 3) is different. Section WCc shown in Figure 7 is the portion of the channel 30c that corresponds to section WC1 (see Figure 3) of the channel 30. Section WCc is a section in which the channel 30c is curved by 90 degrees or more, but since it does not contain a wide section, it is considered a simple curved section rather than a wide curved section. In a simple curved section like section WCc that does not contain a wide section, turbulence of the refrigerant is likely to occur. Such turbulence produces a cooling effect, and the area around where the turbulence occurs becomes cold, thus promoting non-uniformity of the temperature distribution on the mounting surface 21 (see Figures 1 and 2) on which the substrate W is placed.

[0027] In this regard, since the wide curved section (for example, section WC1 in Figure 4) of the holding device 1 of this embodiment contains a wide section (for example, the wide section WD in Figure 4), the generation of turbulence in the wide curved section can be suppressed. As a result, the cooling effect caused by turbulence in the wide curved section is mitigated, and the uniformity of the temperature distribution within the mounting surface 21 on which the substrate W is placed can be improved.

[0028] Of the wide curved sections and isolated curved sections included in the flow path 30, the isolated curved sections will be described next. Section SC1, shown in hatching in Figure 3, is an example of an isolated curved section. In the cross-section shown in Figure 3, an isolated curved section is a section in which the flow path 30 is curved by 90 degrees or more, and the length of the non-formed portion (exemplified as the non-formed portion NF in Figure 8) between one end and the other end of the section (exemplified as length SP in Figure 8) is greater than or equal to the set distance. Details will be explained using Figure 8. In this embodiment, the length of the isolated curved section is 10% or less of the total length of the flow path 30 in the cross-section shown in Figure 3. That is, the length of section SC1 is 10% or less of the total length of the flow path 30.

[0029] Figure 8 is an enlarged view of section SC1 shown in Figure 3. Figure 8 shows the center line Ls, one end Es1, and the other end Es2. The center line Ls is the center line of the channel 30 within the isolated curved section. That is, the center line Ls is the bisector of the width of the channel 30 at each position within the isolated curved section. One end Es1 and the other end Es2 are the one end and the other end of the isolated curved section.

[0030] Using Figure 8, we will explain the two requirements that a section considered to be an isolated curved section must satisfy. First, let's explain the first requirement. In section SC1, the angle between the tangent Ts1 to the center line Ls at one end Es1 and the tangent Ts2 to the center line Ls at the other end Es2 is 90 degrees or more, just like the wide curved section described above (see Figure 5). In other words, section SC1 is a section in which the flow path 30 is curved by 90 degrees or more. Thus, a section of the flow path 30 that is considered an isolated curved section satisfies the requirement of being a curved section, just like the wide curved section described above.

[0031] Next, let's explain the second requirement. In section SC1, the length SP of the non-formed portion NF between one end Es1 and the other end Es2, where the flow path 30 is not formed, is greater than or equal to the set distance. The set distance is the sum of the width Ss1 of the flow path at the position of one end Es1 and the width Ss2 of the flow path at the position of the other end Es2. The width of the flow path 30 here refers to the length of the flow path 30 in the direction perpendicular to the tangent line at each position of the center line Ls. Thus, the section of the flow path 30 that is considered an isolated curved section satisfies both requirements: it is a curved section, and the length of the non-formed portion is greater than or equal to the set distance.

[0032] Figure 9 shows section SC2 included in the flow path 30. It is explained that section SC2 is an isolated curved section different from section SC1 shown in Figures 3 and 8. Among the sections included in the flow path 30, any section whose length is 10% or less of the total length of the flow path 30 and that satisfies the two requirements described above is considered an isolated curved section included in the flow path 30. For example, although section SC2 (shown in Figure 9) is a different section from section SC1 (shown in Figure 8), it satisfies the two requirements described above and is therefore considered a wide curved section, just like section SC1. In this way, the flow path 30 contains countless isolated curved sections with different locations and lengths. In section SC2, the width Ss4 of the flow path at the other end Es4 is very close to 0, so the set distance is approximately equal to the width Ss3 of the flow path at the one end Es3.

[0033] Section SC2 shown in Figure 9 is also an isolated curved section that includes the flow channel outlet OUT. Furthermore, a flow channel 30 is located between the flow channel outlet OUT, which is included in the isolated curved section, and the flow channel inlet IN, which is not included in the said isolated curved section (see Figure 3). As mentioned above, the length of the isolated curved section is less than 10% of the total length of the flow channel 30 in the cross-section, so in this embodiment, there is no isolated curved section that includes both the flow channel inlet IN and the flow channel outlet OUT.

[0034] As described above, the curved section is a section within the flow path 30 where turbulence of the refrigerant is likely to occur, and since the generation of this turbulence produces a cooling effect, the temperature in the curved section tends to be relatively low. On the other hand, the non-formed portion NF of the jointed body 5 where the flow path 30 is not formed tends to be relatively high in temperature. In the isolated curved section of the holding device 1 of the embodiment described above (for example, section SC1 in Figure 8, section SC2 in Figure 9), the length of the non-formed portion between one end and the other is greater than or equal to the set distance. That is, inside such an isolated curved section, a sufficiently large non-formed portion NF is secured to warm the isolated curved section, thereby improving the uniformity of the temperature distribution within the mounting surface 21 on which the substrate W is placed.

[0035] The flow path outlet OUT is the point where the refrigerant, having traveled the entire length of the flow path 30 and absorbed sufficient heat, reaches, and therefore its temperature tends to be relatively high. Thus, the flow path outlet OUT tends to become a temperature singularity that deviates to some extent from the average temperature of the entire assembly 5. Therefore, by including the flow path outlet OUT in an isolated curved section (for example, section SC1 in Figure 8 and section SC2 in Figure 9), the uniformity of the temperature distribution within the mounting surface 21 on which the substrate W is placed can be further improved by adjusting the cooling effect due to turbulence generated in the isolated curved section and by setting the length of the non-formed portion NF to be greater than or equal to a set distance.

[0036] The flow path inlet IN is the point where the refrigerant, which is about to begin absorbing heat from the joint 5, arrives. Therefore, its temperature tends to be relatively low, making it prone to becoming a temperature singularity that deviates to some extent from the average temperature of the entire joint 5. In the holding device 1 of the embodiment described above, a flow path 30 is arranged between the flow path outlet OUT, which is contained within an isolated curved section (for example, section SC1 in Figure 8 and section SC2 in Figure 9), and the flow path inlet IN, which is not contained within the isolated curved section. As a result, the flow path 30 separates the flow path inlet IN, where the temperature tends to be relatively low, from the flow path outlet OUT, where the temperature tends to be relatively high, thus suppressing heat transfer from the flow path outlet OUT to the flow path inlet IN. Consequently, the heating of the refrigerant at the flow path inlet IN by heat transfer from the flow path outlet OUT can be suppressed, thus ensuring the cooling effect of the refrigerant on the joint 5 from the flow path inlet IN to the flow path outlet OUT. When the flow path inlet IN and the flow path outlet OUT are located relatively close to each other, it is preferable to increase the distance between them by arranging a flow path 30 between them as described above.

[0037] As described above, in the cross-section of the joint 5 shown in Figure 3, the temperature tends to be relatively high in the non-formed portions where the flow path 30 is not formed. Therefore, it is preferable to arrange curved sections at each position of the cross-section so that the area of ​​the non-formed portion at each position of the cross-section does not become large. Furthermore, since the area up to the outer edge is limited in the outer peripheral portion of the cross-section, the area that can be used for heat dissipation is limited, so it is also preferable to arrange curved sections in the outer peripheral portion.

[0038] <Modified form of this embodiment> The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from its spirit, for example, the following modifications are also possible.

[0039] In the above embodiment, the length of the wide curved section and the length of the isolated curved section were set to be 10% or less of the total length of the flow path 30 in the cross-section of the joint 5, but this is not limited to this. For example, if, in the cross-section of the joint 5, instead of having one flow path 30 (one set of flow path inlet IN and flow path outlet OUT) as in the above embodiment, there are multiple flow paths (multiple sets of flow path inlet IN and flow path outlet OUT), the length of the wide curved section and the length of the isolated curved section may be 10% or less of the total length of the multiple flow paths formed in the cross-section of the joint 5.

[0040] In the above embodiment, the flow path 30 included both a wide curved section and an isolated curved section, but is not limited to this. The flow path 30 may include a section that is both a wide curved section and an isolated curved section. In other words, the flow path 30 may include a section that satisfies all of the following conditions: it is a curved section, it contains a wide section, and the length of the non-formed portion is greater than or equal to a set distance. Furthermore, the flow path 30 may include only one of either a wide curved section or an isolated curved section.

[0041] In the above embodiment, the flow path 30 included an isolated curved section that encloses the flow path outlet OUT, but it is not limited to this. The flow path 30 may also include an isolated curved section that encloses the flow path inlet IN. That is, the flow path 30 may include an isolated curved section that encloses either the flow path inlet IN or the flow path outlet OUT. Furthermore, if the flow path 30 includes an isolated curved section that encloses the flow path inlet IN, it is preferable that the flow path 30 be positioned between the flow path inlet IN, which is enclosed in the isolated curved section, and the flow path outlet OUT, which is not enclosed in the said isolated curved section, from the viewpoint of ensuring the cooling effect of the refrigerant on the assembly 5 from the flow path inlet IN to the flow path outlet OUT.

[0042] The embodiments of this specification have been described above based on the embodiments and modifications described above. The embodiments described above are for the purpose of facilitating understanding of this specification and do not limit it. This specification may be modified and improved without departing from its spirit and the scope of the claims, and equivalents thereof are included in this specification. Furthermore, any technical features that are not described as essential in this specification may be deleted as appropriate. [Explanation of symbols]

[0043] 1...Holding device 5…Zygote 5a…hole 10…Base 11…First base 11a, 11b… Main surface (of the first base) 12…Second base 12a, 12b… Main surface (of the second base) 12b…main surface 14…hole 20…Ceramic base material 20a, 20b… Main surface (of the ceramic substrate) 21… Mounting surface 22… Mounting surface for focus ring 23…hole 24...Electrode 30…flow channel FR...Focus Ring IN...channel inlet NF…Non-formed part OUT…Flow path outlet

Claims

[Claim 1] A holding device, It comprises a plate-shaped member having a mounting surface on which an object is placed, and having a flow path formed inside through which a refrigerant flows, In the cross-section of the plate-like member at the position where the flow channel is formed, the flow channel includes a wide curved section in which the flow channel is curved by 90 degrees or more, while encompassing a wide section in which the flow channel has a wide width. The width of the channel in the wide section is wider than the width of the channel at one end of the wide curved section and the width of the channel at the other end of the wide curved section. A holding device characterized in that, in the cross-section, the shape of the flow channel wall defining the inside of the wide section contained within the wide curved section is rounded.

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