Holding member and holding device

Abstract

To provide a holding member which increases the thermal uniformity of the surface of a tabular member, and a holding device having the holding member.SOLUTION: In a ceramic member 10, three heater lines 42 is formed of: a first heater line 42-1 formed in the outermost circumference side of a heater electrode 41; a second heater line 42-2 formed along the first heater line 42-1 in an inner side from the first heater line 42-1 by one line; and a third heater line 42-3 formed along the second heater line 42-2 in an inner side from the second heater line 42-2 by one line. The outermost pitch P1 as the distance between the first heater line 42-1 and the second heater line 42-2 is made larger than the inner pitch P0 as the distance between the second heater line 42-2 and the third heater line 42-3.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a holding member and a holding device for holding an object. [Background technology]

[0002] Patent Document 1 discloses a ceramic heater (holding member) having heater electrodes (heat generating elements) that are embedded in a disc-shaped ceramic plate (plate-shaped member) and formed concentrically. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-126770 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the ceramic heater disclosed in Patent Document 1, since there is no heater electrode on the outer periphery of the ceramic plate (the portion radially outward of the heater electrode), the temperature of the surface of the ceramic plate (wafer mounting surface) is likely to decrease, which may reduce the thermal uniformity of the surface of the ceramic plate.

[0005] Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a holding member that improves thermal uniformity on the surface of a plate-shaped member, and a holding device having this holding member. [Means for solving the problem]

[0006] One form of the present disclosure made to solve the above problems is characterized in that in a holding member having a plate-shaped member and a heating element embedded in the plate-shaped member and having at least three linear heating lines formed side by side with a gap therebetween, the three heating lines are formed by a first heating line formed on the outermost side of the heating element, a second heating line formed along the first heating line one line inside the first heating line, and a third heating line formed along the second heating line one line inside the second heating line, and an outermost pitch that is a distance between the first heating line and the second heating line is larger than an inner pitch that is a distance between the second heating line and the third heating line.

[0007] According to this embodiment, by making the outermost pitch larger than the inner pitch, the first heating line formed on the outermost side of the heating element can be formed on the further outer side of the plate-shaped member. Therefore, the temperature can be increased at the outer periphery of the plate-shaped member by heat generation by the first heating line. Therefore, it is possible to suppress a decrease in the surface temperature at the outer periphery of the plate-shaped member. Therefore, the thermal uniformity of the surface of the plate-shaped member is improved.

[0008] In the above aspect, the outermost pitch is preferably less than 140% of the inner pitch.

[0009] According to this embodiment, the outermost pitch is not excessively large, and therefore the distance between the first and second heat generating lines is not excessively large, and a sufficient amount of heat can be generated. Therefore, the temperature drop between the first and second heat generating lines can be suppressed. Therefore, the temperature uniformity of the surface of the plate-shaped member is improved more reliably.

[0010] In the above aspect, it is preferable that the line width of the first heating line is smaller than the line width of the second heating line.

[0011] According to this aspect, the resistance value of the first heat generating line can be increased to make the heat generation amount of the first heat generating line greater than the heat generation amount of the second heat generating line. Therefore, the heat generation amount of the first heat generating line can be increased more effectively in the outer periphery of the plate-shaped member, thereby raising the temperature. Therefore, the temperature drop of the surface in the outer periphery of the plate-shaped member can be more effectively suppressed. Therefore, the thermal uniformity of the surface of the plate-shaped member is more effectively improved.

[0012] Another aspect of the present disclosure made to solve the above problem is characterized in that a holding device has the holding member of the above aspect. Effect of the Invention

[0013] According to the holding member and holding device of the present disclosure, the thermal uniformity of the surface of the plate-like member is improved. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic perspective view of an electrostatic chuck according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an XZ cross-sectional view of the ceramic member of the present embodiment. [Diagram 3] FIG. 2 is a top view of a heater electrode according to the present embodiment. [Figure 4] FIG. 4 is an enlarged view of the area surrounded by the dashed line in FIG. [Diagram 5] FIG. 13 is a diagram showing the line width and outermost peripheral pitch of the first heater line under each of the conditions evaluated, and the temperature difference as an evaluation result. [Figure 6] FIG. 6 is a graph showing the evaluation results of the temperature distribution on the holding surface under each of the conditions shown in FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] An embodiment of a holding member and a holding device according to the present disclosure will be described. In this embodiment, a ceramic member 10 is exemplified as the holding member, and an electrostatic chuck 1 is exemplified as the holding device. The electrostatic chuck 1 is used in semiconductor manufacturing equipment such as a film forming apparatus (such as a CVD film forming apparatus or a sputtering film forming apparatus) or an etching apparatus (such as a plasma etching apparatus).

[0016] <Overall explanation of electrostatic chuck> The electrostatic chuck 1 of the present embodiment is a device that attracts and holds a semiconductor wafer W by electrostatic attraction, and is used, for example, to fix the semiconductor wafer W in a vacuum chamber of a semiconductor manufacturing device. The semiconductor wafer W is an example of an "object" in the present disclosure.

[0017] 1, the electrostatic chuck 1 includes a ceramic member 10, a base member 20, and a bonding layer 30 that bonds the ceramic member 10 to the base member 20. The ceramic member 10 is an example of the "holding member" of the present disclosure.

[0018] In the following description, for convenience of explanation, the X, Y and Z axes are defined as shown in Fig. 1. Here, the Z axis is an axis in the central axis direction of the electrostatic chuck 1 (the vertical direction in Fig. 1), and the X and Y axes are axes in the radial directions of the electrostatic chuck 1.

[0019] 1 and 2, the ceramic member 10 is a plate-like, more specifically, disk-like member, and is formed of a ceramic substrate 40. The ceramic member 10 has a stepped disk shape in which two disks of different diameters are overlapped with a common central axis (more specifically, a disk-shaped upper stage portion 10a having a smaller diameter is overlapped on a disk-shaped lower stage portion 10b having a larger diameter).

[0020] Although various ceramics are used as the ceramics forming the ceramic member 10, it is preferable to use ceramics containing aluminum oxide (alumina, Al2O3) or aluminum nitride (AlN) as the main component from the viewpoints of strength, wear resistance, plasma resistance, etc. Here, the main component means the component with the highest content (for example, a component with a volume content of 90 vol% or more).

[0021] 1 and 2, the ceramic member 10 has a holding surface 11 (upper surface) that holds a semiconductor wafer W, and a lower surface 12 that is provided on the opposite side to the holding surface 11 in the thickness direction (i.e., the Z-axis direction) of the ceramic member 10. The holding surface 11 is an example of a surface of a "holding member" in the present disclosure.

[0022] The upper portion 10a of the ceramic member 10 has a diameter of, for example, about 150 to 300 mm, and the lower portion 10b has a diameter of, for example, about 180 to 400 mm. The thickness of the ceramic member 10 is, for example, about 2 to 6 mm. The thermal conductivity of the ceramic member 10 is preferably within a range of 10 to 50 W / mK (more preferably, 18 to 30 W / mK).

[0023] The ceramic member 10 also has a chuck electrode (adsorption electrode) (not shown) inside it. When a voltage is applied to the chuck electrode from a power source (not shown), an electrostatic force of attraction is generated in the chuck electrode, and the semiconductor wafer W is attracted to and held on the holding surface 11 by the electrostatic force of attraction.

[0024] The base member 20 is disposed on the opposite side of the ceramic member 10 from the holding surface 11. The base member 20 is formed, for example, in a cylindrical shape. The base member 20 is formed, for example, from a metal (for example, aluminum or an aluminum alloy), but may be formed from a material other than metal.

[0025] 1, the base member 20 has an upper surface 21 and a lower surface 22 provided on the opposite side to the upper surface 21 in the thickness direction (i.e., the Z-axis direction) of the base member 20. The upper surface 21 of the base member 20 is thermally connected to the lower surface 12 of the ceramic member 10 via a bonding layer 30.

[0026] The diameter of the base member 20 is, for example, about 180 to 400 mm. The thickness (dimension in the Z-axis direction) of the base member 20 is, for example, about 20 to 50 mm. The thermal conductivity of the base member 20 (assumed to be aluminum) is desirably within a range of 160 to 250 W / mK (preferably, about 230 W / mK).

[0027] The bonding layer 30 is disposed between the lower surface 12 of the ceramic member 10 and the upper surface 21 of the base member 20, and bonds the ceramic member 10 and the base member 20 in a heat-transferable manner.

[0028] The bonding layer 30 is made of an adhesive material of resin (such as silicone resin, acrylic resin, or epoxy resin) containing a thermally conductive filler. The thickness (dimension in the Z-axis direction) of the bonding layer 30 is, for example, about 0.1 to 1.5 mm. The thermal conductivity of the bonding layer 30 is, for example, 1.0 W / mK. The thermal conductivity of the bonding layer 30 (assuming a silicone resin) is desirably within a range of 0.1 to 2.0 W / mK (preferably 0.5 to 1.5 W / mK).

[0029] <About the heater electrode> In this embodiment, as shown in Fig. 2, the ceramic member 10 has a heater electrode 41. The heater electrode 41 is embedded inside the ceramic substrate 40 that forms the ceramic member 10, and generates heat to heat the semiconductor wafer W held on the holding surface 11. The heater electrode 41 is formed of, for example, tungsten or a molybdenum alloy, but may be formed of other metals. The heater electrode 41 is an example of a "heating element" in the present disclosure.

[0030] The heater electrode 41 has linear heater lines 42 formed in a substantially concentric shape as shown in Fig. 3 when viewed in the thickness direction of the ceramic member 10, and the heater lines 42 have a line width of about 0.1 mm to 1.0 mm. The heater lines 42 are an example of a "heating line" in the present disclosure.

[0031] <Measures to improve the temperature uniformity of the holding surface> 3 and 4, the heater electrode 41 has a plurality of (at least three or more) heater lines 42 arranged at intervals. The heater electrode 41 has a first heater line 42-1, a second heater line 42-2, and a third heater line 42-3 on its outer periphery as the three heater lines 42.

[0032] The first heater line 42-1 is a heater line 42 formed on the outermost side (i.e., the outermost side in the radial direction) of the heater electrode 41. The second heater line 42-2 is a heater line 42 formed along the first heater line 42-1, one line inward in the radial direction from the first heater line 42-1. The third heater line 42-3 is a heater line 42 formed along the second heater line 42-2, one line inward in the radial direction from the second heater line 42-2.

[0033] Here, "formed along the first heater line 42-1 (or the second heater line 42-2)" means that the heater line 42-1 is formed linearly while maintaining an equal distance from the first heater line 42-1 (or the second heater line 42-2) in the circumferential direction of the heater electrode 41, i.e., in the line direction (linear direction) of the first heater line 42-1 (or the second heater line 42-2).

[0034] In this embodiment, the pitch (spacing) of the heater lines 42 on the outer periphery of the heater electrode 41 is adjusted to suppress the occurrence of specific temperature collapse that is likely to occur on the outer periphery of the holding surface 11 of the ceramic member 10. Specifically, as shown in Fig. 4, the outermost periphery pitch P1 is made larger than the inner pitch P0.

[0035] Here, the outermost pitch P1 is the distance between the center line of the first heater line 42-1 and the center line of the second heater line 42-2. Also, the inner pitch P0 is the distance between the center line of the second heater line 42-2 and the center line of the third heater line 42-3. Note that the pitch of the heater line 42 radially inward of the third heater line 42-3 is also the same size as the inner pitch P0.

[0036] In this manner, in this embodiment, by making the outermost pitch P1 larger than the inner pitch P0, the first heater line 42-1 formed on the outermost side of the heater electrode 41 can be formed on the further outer side of the ceramic substrate 40. Therefore, the temperature can be increased in the outer periphery of the ceramic substrate 40 by heat generation by the first heater line 42-1. Therefore, the temperature drop of the holding surface 11 in the outer periphery of the ceramic substrate 40 can be suppressed. Therefore, the thermal uniformity of the holding surface 11 is improved.

[0037] In this embodiment, as shown in FIG. 4, the line width b1 of the first heater line 42-1 is set smaller than the line width b0 of the second heater line 42-2 and the third heater line 42-3.

[0038] This increases the resistance value of the first heater line 42-1, and the heat generation amount of the first heater line 42-1 can be made larger than the heat generation amount of the second heater line 42-2 and the third heater line 42-3. Therefore, the heat generation amount by the first heater line 42-1 can be increased more effectively at the outer periphery of the ceramic substrate 40, and the temperature can be increased. Therefore, the temperature drop of the holding surface 11 at the outer periphery of the ceramic substrate 40 can be more effectively suppressed. Therefore, the temperature uniformity of the holding surface 11 is more effectively improved. The line width of the heater line 42 inside the third heater line 42-3 is also the line width b0.

[0039] Here, the applicant evaluated the temperature distribution of the holding surface 11 under each condition of the line width b1 and the outermost pitch P1 of the first heater line 42-1 as shown in Fig. 5, and obtained the evaluation results shown in Fig. 5 and Fig. 6. The reference line width b0 was set to 0.5 mm, and the reference inner pitch P0 was set to 5.0 mm. In Fig. 5, the value in parentheses attached to the value of the line width b1 indicates the ratio of reduction with respect to the line width b0, and the value in parentheses attached to the value of the outermost pitch P1 indicates the ratio of increase with respect to the inner pitch P0.

[0040] It was found that under conditions (5) to (8) in which the outermost pitch P1 was made larger than the inner pitch P0, the temperature difference ΔT (i.e., the temperature difference between the radial center and outer periphery of the retaining surface 11) was small (2.0 to 3.0°C), the temperature distribution of the retaining surface 11 was made uniform, and the thermal uniformity of the retaining surface 11 was improved.

[0041] In particular, it was found that under conditions (6) and (7) in which the outermost pitch P1 was less than 140% of the inner pitch P0 (more specifically, 120% and 130%), the temperature difference ΔT was smallest (2.0°C), the temperature distribution of the holding surface 11 was most uniform, and the thermal uniformity of the holding surface 11 was most improved.

[0042] Therefore, in this embodiment, the outermost pitch P1 is set to be greater than 100% of the inner pitch P0 and less than 140% of the inner pitch P0.

[0043] As a result, the outermost pitch P1 is not excessively large, and the distance between the first heater line 42-1 and the second heater line 42-2 is not excessively large, so that a sufficient amount of heat can be generated. Therefore, a temperature drop between the first heater line 42-1 and the second heater line 42-2 can be suppressed. Therefore, the temperature uniformity of the holding surface 11 is improved more reliably.

[0044] In addition, under conditions (3), (5) to (8) in which the line width b1 is 60% (i.e., -40%) of the line width b0, it was found that the temperature difference ΔT becomes small (2.0 to 4.1°C), the temperature distribution of the holding surface 11 is made uniform, and the thermal uniformity of the holding surface 11 is improved.

[0045] It should be noted that the above-described embodiments are merely examples and do not limit the present disclosure in any way. Needless to say, various improvements and modifications are possible without departing from the spirit and scope of the present disclosure.

[0046] For example, the heater electrode 41 is not limited to being formed in a substantially concentric shape as shown in FIG. 3, and may be formed in other shapes (such as a substantially concentric arc shape or a sector shape). [Explanation of symbols]

[0047] 1. Electrostatic chuck 10 Ceramic materials 11 Holding surface 20 Base material 30 Bonding layer 40 Ceramic Substrate 41 Heater electrode 42 Heater Line 42-1 First heater line 42-2 Second heater line 42-3 3rd heater line W Semiconductor wafer P0 Inner pitch P1 Outermost pitch b0 (2nd and 3rd heater line) line width b1 (first heater line) line width ΔT temperature difference

Claims

1. A plate-like member; a heating element embedded in the plate-like member and having at least three linear heating lines arranged at intervals, The three heat generating lines are A first heating line formed on the outermost peripheral side of the heating element; a second heat generation line formed along the first heat generation line and one line inward from the first heat generation line; a third heat generation line formed along the second heat generation line and one line inward from the second heat generation line; is formed by making an outermost pitch, which is a distance between the first heat generation line and the second heat generation line, larger than an inner pitch, which is a distance between the second heat generation line and the third heat generation line; A holding member comprising:

2. The holding member according to claim 1, the outermost pitch is less than 140% of the inner pitch; A holding member comprising:

3. The holding member according to claim 1 or 2, a line width of the first heating line is smaller than a line width of the second heating line; A holding member comprising:

4. A holding device for holding an object, comprising the holding member according to claim 1 or 2.

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