Wafer support table

Abstract

The present invention provides a wafer support table, which can improve the thermal uniformity of the periphery of a wafer. The wafer support table of the present invention comprises: a ceramic substrate having a wafer mounting surface and a plurality of heaters embedded in the ceramic substrate. The ceramic substrate has a first heater forming surface, a second heater forming surface and a third heater forming surface in sequence from the wafer mounting surface toward the surface opposite to the wafer mounting surface. The plurality of heaters include a first heater arranged on the first heater forming surface, a second heater arranged on the second heater forming surface and a third heater arranged on the third heater forming surface. The first heater is arranged in a manner located at the center of the ceramic substrate. The second heater is arranged in a manner located on the periphery of the first heater. The third heater is arranged in a manner overlapping with the second heater and is respectively arranged in an area formed by dividing the third heater forming surface into a plurality of areas by a line segment in a radial direction.

Description

Technical Field

[0001] The present invention relates to a wafer support table. Background Art

[0002] Conventionally, there is known a ceramic wafer support table used when performing a film forming process such as plasma CVD on a wafer, in which heaters for heating the wafer are arranged in multiple layers. For example, Patent Document 1 describes an electrically independent multiple layer heater.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6758143 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, although such a wafer support table can prevent the temperature of the center portion from decreasing due to heat dissipation from the axis, there is a possibility that thermal uniformity may deteriorate due to the influence from the periphery of the wafer support table.

[0008] The present invention has been made to solve such a problem, and a main object of the present invention is to improve the thermal uniformity of the periphery of a wafer.

[0009] Means for solving problems

[0010] The wafer support table of the present invention comprises: a ceramic base having a wafer placement surface, and a plurality of heaters embedded in the ceramic base.

[0011] The ceramic base has a first heater forming surface, a second heater forming surface, and a third heater forming surface in order from the wafer mounting surface toward the surface opposite to the wafer mounting surface.

[0012] The plurality of heaters include a first heater provided on the first heater forming surface, a second heater provided on the second heater forming surface, and a third heater provided on the third heater forming surface.

[0013] The first heater is arranged in a manner of being located at the center of the ceramic substrate,

[0014] The second heater is disposed so as to be located on the outer periphery of the first heater.

[0015] The third heater is provided so as to overlap with the second heater, and is provided in each of a plurality of regions obtained by dividing the third heater forming surface by a line segment in a radial direction.

[0016] In the wafer support table of the present invention, since the third heaters are provided in the areas formed by dividing the third heater forming surface into a plurality of areas by radial line segments, the plurality of third heaters can be temperature controlled separately, thereby suppressing the influence on the thermal uniformity caused by the peripheral factors. In addition, by burying the first heater at a position different from the forming surface of other heaters and closer to the wafer mounting surface, the jumper wires of other heaters will not pass through, the design freedom of the first heater is increased, and the thermal uniformity is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a cross-sectional view of a wafer support table used in a plasma generating device.

[0018] Figure 2 This is an explanatory diagram showing the relationship between the coil-shaped heater and the jumper wire.

[0019] Figure 3 It is a top view of the first heater forming surface of the ceramic base.

[0020] Figure 4 It is a top view of the second heater forming surface of the ceramic base.

[0021] Figure 5 It is a top view of the surface of the ceramic substrate on which the third heater is formed. DETAILED DESCRIPTION

[0022] Below, while referring to the attached Figure 1 Preferred embodiments of the present invention will be described. Figure 1 This is a cross-sectional view of a wafer support table used in a plasma generating device. Figure 2 This is an explanatory diagram showing the relationship between the coil-shaped heater and the jumper wire. Figure 3 to Figure 5 FIG. 1 is a top view of the first to third heater forming surfaces of the ceramic substrate. Figure 3 to Figure 5 In the figure, the coil-shaped heater is indicated by hatching.

[0023] The wafer support table includes a ceramic base having a wafer placement surface, a plurality of heaters embedded in the ceramic base, and a cylindrical shaft provided on a surface of the ceramic base opposite to the wafer placement surface.

[0024] The ceramic base has a first heater forming surface, a second heater forming surface, and a third heater forming surface in this order from the wafer mounting surface toward the surface opposite to the wafer mounting surface.

[0025] The plurality of heaters include a first heater provided on a first heater forming surface, a second heater (second heaters X, Y) provided on a second heater forming surface, and a third heater (third heaters A to D) provided on a third heater forming surface. The first heater is provided so as to be located at the center of the ceramic base.

[0026] The first heater is formed by wiring a coil from one terminal to the other terminal in a single stroke.

[0027] The second heater includes a second heater X disposed on the inner side of the second heater forming surface and a second heater Y disposed on the outer side of the second heater forming surface. The second heaters X and Y are both disposed in a manner located on the periphery of the first heater. After the second heater X is led out from one terminal to the outside of the first heater through a second heater X jumper, the coil is wired in a one-stroke manner and introduced to another terminal on the center side through another second heater X jumper. After the second heater Y is led out from one terminal to the outside of the second heater X through a second heater Y jumper, the coil is wired in a one-stroke manner and introduced to another terminal on the center side through another second heater Y jumper. The second heater X jumper and the second heater Y jumper are disposed on the second heater forming surface. That is, the second heater X jumper and the second heater Y jumper are formed on the same surface as the second heaters X and Y. It should be noted that the same surface is a surface that is highly overlapped with the second heaters X and Y. For example, when the second heaters X and Y are coil-shaped, the upper portion of the coil closest to the wafer mounting surface and the lower portion of the coil farthest from the wafer mounting surface are on the same surface (the same applies hereinafter).

[0028] The third heater includes four third heaters A to D. The third heaters A to D are respectively provided on the third heater forming surface divided into a plurality of portions by a line segment in the radial direction (in Figure 5In the area formed by the third heater (4 in the figure), they all overlap with the second heater when viewed from above. Here, the third heater A and the third heater B are integrated. Specifically, after the third heater A is led out from one terminal to the outside through the third heater A jumper, the coil is wired in a one-stroke method and reaches the connection part of the third heater A and B common jumper (connected to the ground terminal). After the third heater B is wired from the connection part in a one-stroke method, it is introduced to another terminal on the center side through the third heater B jumper. In addition, the third heater C and the third heater D are integrated. Specifically, after the third heater C is led out from one terminal to the outside through the third heater C jumper, the coil is wired in a one-stroke method and reaches the connection part of the third heater C and D common jumper (connected to the ground terminal). After the third heater D is wired from the connection part in a one-stroke method, it is introduced to another terminal on the center side through the third heater D jumper. The jumper for the third heater A, the jumper for the third heater B, the common jumper for the third heaters A and B, the jumper for the third heater C, the jumper for the third heater D, and the common jumper for the third heaters C and D are all arranged on the third heater forming surface in the same way as the third heaters A to D, that is, these jumpers are formed on the same surface as the third heaters A to D.

[0029] Terminal holes are formed on the ceramic base from the surface opposite to the wafer mounting surface toward the terminals corresponding to the first heater, the second heater (second heater X, Y) and the third heater (third heaters A to D). The terminal holes corresponding to the first heater, the second heater (second heater X, Y) and the third heater (third heaters A to D) become deeper in proportion to the depth of each heater.

[0030] As described above, the first heater, the second heater (second heaters X, Y) and the third heater (third heaters A to D) are in the shape of coils. The second heater is connected to the lower portion of the coil located on the surface side opposite to the wafer placement surface in the coil of the second heater by a jumper wire. The third heater is connected to the upper portion of the coil located on the wafer placement surface side in the coil of the third heater by a jumper wire.

[0031] The ceramic substrate has an RF electrode on the wafer mounting surface side relative to the first heater. The rod for supplying power to the first heater, the rod for supplying power to the second heater (second heaters X, Y), the rod for supplying power to the third heater (third heaters A to D), and the rod connected to the RF electrode all have the same length of the portion protruding from the axial downward direction.

[0032] The second heaters are respectively provided in regions obtained by dividing the second heater forming surface into a plurality of regions (two regions in this case) by boundaries that are concentric with the ceramic base.

[0033] In the wafer support table of the present embodiment described above, since the third heaters A to D are provided in the areas formed by dividing the third heater formation surface by the line segments in the radial direction into a plurality of areas, the temperature of the plurality of third heaters A to D can be controlled separately, thereby suppressing the influence on the thermal uniformity caused by the peripheral factors. In addition, by burying the first heater at a position different from the formation surface of other heaters and near the wafer mounting surface, the jumper wires of other heaters will not pass through, the design freedom of the first heater is increased, and the thermal uniformity is improved.

[0034] In addition, since the ring-shaped second heater and the fan-shaped third heater overlap, more precise temperature control can be performed.

[0035] Furthermore, the terminal holes corresponding to the first heater, the second heater (second heater X, Y) and the third heater (third heaters A to D) are deepened in proportion to the depth of each heater. Therefore, there is no jumper extending in the thickness direction of the ceramic base, and manufacturing becomes easy.

[0036] Furthermore, since the jumper wire for the second heater is led out from the side of the coil center of the second heater that is closer to the side opposite to the wafer mounting surface (the lower part of the coil in this embodiment), the distance D1 from the wafer mounting surface to the jumper wire can be increased (see Figure 2 ), which can reduce the impact caused by the heat generated by the jumper.

[0037] Furthermore, since the jumper wire for the third heater is led out from the side closer to the wafer mounting surface than the coil center of the third heater (the upper part of the coil in this embodiment), the distance D2 from the surface of the ceramic substrate opposite to the wafer mounting surface to the jumper wire can be shortened (see Figure 2 ) becomes longer. Thus, the length of the hole for mounting the terminal can be ensured.

[0038] Furthermore, since the lengths of the rods for supplying power to the plurality of heaters and RF electrodes protruding from the shaft are uniform, the structure on the support rod side can be simplified.

Claims

1. A wafer support table comprising: a ceramic base having a wafer placement surface, and a plurality of heaters embedded in the ceramic base, The ceramic base has a first heater forming surface, a second heater forming surface, and a third heater forming surface in order from the wafer mounting surface toward the surface opposite to the wafer mounting surface. The plurality of heaters include a first heater provided on the first heater forming surface, a second heater provided on the second heater forming surface, and a third heater provided on the third heater forming surface. The first heater is arranged in a manner of being located at the center of the ceramic substrate, The second heater is disposed so as to be located on the outer periphery of the first heater, and the second heaters are respectively disposed in a plurality of regions formed by dividing the second heater forming surface by boundaries that are concentric with the ceramic substrate. The third heater is provided so as to overlap with the second heater, and is provided in each of a plurality of regions obtained by dividing the third heater forming surface by a line segment in a radial direction.

2. The wafer support table according to claim 1, wherein a second heater jumper is provided on the second heater forming surface, The third heater jumper is provided on the third heater forming surface. 3 . The wafer support table according to claim 1 , wherein the terminal holes for supplying power to the first heater, the second heater, and the third heater are deeper in proportion to the depth of each heater.

4. The wafer support table according to claim 1 or 2, wherein the first heater, the second heater and the third heater are in the shape of coils, and the second heater is connected to a surface side of the second heater that is closer to the side opposite to the wafer placement surface than the coil center of the second heater by a jumper wire. The third heater is connected by a jumper wire to a position closer to the wafer mounting surface than the coil center of the third heater.

5. The wafer support table according to claim 1 or 2, wherein the ceramic base has an RF electrode on a side closer to the wafer mounting surface than the plurality of heaters, and has a cylindrical shaft on a surface opposite to the wafer mounting surface. The rod for supplying power to the first heater, the rod for supplying power to the second heater, the rod for supplying power to the third heater, and the rod connected to the RF electrode all have the same length of the portion protruding from the shaft.

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