JP2016100473A - Electrostatic chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic chuck in which the temperature distribution of the support face of a main body board for supporting a processing target object can be made uniform, and durability and reliability can be enhanced.SOLUTION: An electrostatic chuck 1 has a metal base 12 having a front surface 121 and a back surface 122, a main body board 11 which is disposed at the surface 121 side of the metal base 12, has a support face 111 for supporting a semiconductor wafer (processing target object) 8 and is formed of ceramic, a suction electrode 21 which is provided to the main body board 11 and sucks the semiconductor wafer 8, a resin part 13 disposed between the metal base 12 and the main body board 11, a first heater part 41 which is provided to the main body board 11 and comprises a heater electrode 411, and a second heater part 42 which is provided to the resin part 13 and comprises a heater electrode 421. Each of the first heater part 41 and the second heater part 42 has plural heating areas. The number of the heating areas of the second heater part 42 is larger than the number of the heating areas of the first heater part 41.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrostatic chuck.

  Conventionally, in a semiconductor manufacturing apparatus, processing such as dry etching (for example, plasma etching) is performed on a semiconductor wafer (for example, a silicon wafer). In order to increase processing accuracy such as dry etching, it is necessary to securely support the semiconductor wafer. An electrostatic chuck is known as means for supporting a semiconductor wafer.

  The electrostatic chuck includes a main body substrate made of ceramic, an adsorption electrode and a heater provided on the main body substrate. The electrostatic chuck attracts and supports the semiconductor wafer on the upper surface (support surface) of the main body substrate using electrostatic attraction generated when a voltage is applied to the attracting electrode. Further, the semiconductor wafer adsorbed and supported on the support surface of the main body substrate is heated by the heater.

  By the way, if the temperature of the semiconductor wafer sucked and supported on the support surface of the main body substrate varies, the processing accuracy decreases. Therefore, in order to increase the processing accuracy, the support surface of the main substrate supporting the semiconductor wafer by suction is reduced. It is required to make the temperature distribution uniform. For example, Patent Document 1 discloses an electrostatic chuck in which a heater arranged on the same plane is divided into a plurality of regions and controlled in each region.

JP 2010-225941 A

  However, in the electrostatic chuck of Patent Document 1, when resistance variation occurs in each region of the heater, the temperature distribution on the support surface of the main body substrate that sucks and supports the semiconductor wafer varies, and the temperature distribution becomes uniform. May not be possible. In addition, if there is a difference in heat generation temperature in each region of the heater, thermal stress is generated inside the main body substrate. For this reason, when used at a high temperature for a long period of time, this thermal stress may be repeatedly generated, resulting in a failure such as a crack in the main body substrate.

  The present invention has been made in view of such a background, and is an electrostatic chuck capable of making the temperature distribution of the support surface of the main body substrate supporting the object to be processed uniform and improving the durability and reliability. Is to provide.

  The present invention includes a metal base having a front surface and a back surface, a support surface that is disposed on the front surface side of the metal base and supports an object to be processed, and is made of ceramic, and is provided on the main substrate. An adsorption electrode for adsorbing the object to be processed; a resin portion disposed between the metal base and the main body substrate; a first heater portion provided on the main body substrate and including a heater electrode; A second heater part formed of a heater electrode, and each of the first heater part and the second heater part has a plurality of heating areas, and the heating area of the second heater part Is more than the number of the heating regions of the first heater unit.

  In the electrostatic chuck, a first heater part is provided on the main body substrate, and a second heater part is provided on the resin part. By adopting a two-layered heater, the variation in temperature distribution on the support surface caused by the first heater part provided on the main body substrate can be adjusted and made uniform by the second heater part provided on the resin part. . In particular, since the number of heating regions of the second heater unit is larger than the number of heating regions of the first heater unit, variation in the temperature distribution on the support surface can be finely adjusted, and the temperature distribution can be made uniform with higher accuracy. Thereby, the temperature distribution of the support surface of the main body substrate can be made uniform. And the temperature variation of the to-be-processed object supported by the support surface of a main body board | substrate can also be reduced.

  One heater (first heater part) is provided on the main body substrate, and the other heater (second heater part) is provided on the resin part. In particular, the second heater portion is provided in the resin portion having a Young's modulus larger than that of the ceramic constituting the main body substrate and a small stress generated by heat deformation. Therefore, it is possible to suppress the generation of thermal stress due to the difference in the heat generation temperature between the heaters as in the prior art and the accompanying cracking of the main body substrate, and the durability and reliability can be improved. Thereby, even if it is a case where it uses for a long time at high temperature, durability and reliability are fully securable.

  As described above, according to the present invention, it is possible to provide an electrostatic chuck capable of making the temperature distribution on the support surface of the main body substrate supporting the object to be processed uniform and improving the durability and reliability. it can.

  In the electrostatic chuck, the first heater portion is provided between the heating regions, further includes a boundary region that separates the heating regions, and when the main substrate is viewed from the thickness direction, The boundary region of one heater part may be arranged so as to overlap the heating region of the second heater part. In this case, the variation in temperature distribution of the support surface generated in the boundary region of the first heater portion of the main body substrate can be adjusted and uniformed by the heating region of the second heater portion of the resin portion.

  In the electrostatic chuck, when the variation of the temperature distribution of the support surface generated by the first heater unit provided on the main body substrate is adjusted by the second heater unit provided on the resin unit, for example, the first heater unit and the second heater unit What is necessary is just to adjust the heater output of a heater part suitably.

  The main body substrate is made of ceramic. That is, the thermal conductivity tends to be higher than that of the resin portion made of resin. Therefore, the main heater (main heater) for heating the support surface of the main body substrate and the workpiece supported on the support surface is the first heater portion provided on the main body substrate, and the adjustment heater is provided on the resin portion. A heater part is preferred. In this case, what is necessary is just to make the sum total of the heater output of a 1st heater part larger than the sum total of the heater output of a 2nd heater part.

  The main body substrate is configured to be capable of adsorbing an object to be processed using an electrostatic attraction generated when a voltage is applied to an adsorption electrode provided on the main body substrate. Examples of the object to be processed include a semiconductor wafer and a glass substrate.

  The main body substrate can be composed of, for example, a plurality of laminated ceramic layers. With such a configuration, various structures (for example, heater electrodes) can be easily formed inside the main body substrate.

  As the ceramic material constituting the main body substrate, for example, a sintered body mainly composed of alumina, yttria (yttrium oxide), aluminum nitride, silicon carbide, or the like can be used.

  The material of the conductor constituting the electrode for adsorption and the heater electrode of the first heater part is not particularly limited, but when these conductors and ceramic portion (main body substrate) are formed by a simultaneous firing method, The metal powder needs to have a melting point higher than the firing temperature of the main body substrate. As the metal powder in the conductor, for example, tungsten (W), molybdenum (Mo), and alloys thereof can be used.

  As a metal material constituting the metal base, titanium (Ti), copper (Cu), aluminum (Al), an alloy thereof, or the like can be used. Further, the metal base may be provided with a refrigerant flow path for circulating the cooling medium.

The resin part can be constituted by, for example, a plurality of laminated resin layers. For example, a polyimide resin or the like can be used as the resin material constituting the resin portion.
For example, copper (Cu), nickel (Ni) alloy, stainless steel, or the like can be used as the material of the conductor constituting the heater electrode of the second heater section.

  The resin part and the main body substrate are bonded (adhered) to each other through an adhesive layer or the like, for example. Similarly, the resin part and the metal base are bonded (adhered) to each other through an adhesive layer or the like, for example. As a material constituting the adhesive layer, for example, a resin material such as a silicone resin, an acrylic resin, an epoxy resin, a polyimide resin, a polyamideimide resin, or a polyamide resin can be used.

FIG. 3 is an explanatory cross-sectional view showing the structure of the electrostatic chuck according to the first embodiment. It is sectional explanatory drawing to which a part of electrostatic chuck was expanded. (A) is a top view which shows a 1st heater part, (B) is a top view which shows the heating area | region of a 1st heater part. It is a top view which shows the heating area | region of a 2nd heater part. (A) is sectional explanatory drawing which shows the process of adhere | attaching a metal sheet on a 1st resin layer, (B) is sectional explanatory drawing which shows the process of forming the heater electrode of a 2nd heater part on a 1st resin layer. It is. (A) is sectional explanatory drawing which shows the process of mounting a 2nd resin layer on a 1st resin layer, (B) is sectional explanatory drawing which shows the process of laminating | stacking and crimping | bonding a 1st resin layer and a 2nd resin layer. It is.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
As shown in FIGS. 1 to 4, the electrostatic chuck 1 of the present embodiment is disposed on a metal base 12 having a front surface 121 and a back surface 122, and on the front surface 121 side of the metal base 12, and is a semiconductor wafer (object to be processed). 8, a main body substrate 11 made of ceramic, an adsorption electrode 21 provided on the main body substrate 11 for adsorbing a semiconductor wafer (object to be processed) 8, a metal base 12, and a main body The resin part 13 disposed between the substrate 11, the first heater part 41 provided on the main body substrate 11 and made of the heater electrode 411, and the second heater part 42 provided on the resin part 13 and made of the heater electrode 421. And.

  As shown in the figure, the first heater section 41 and the second heater section 42 have a plurality of heating regions 412 and 422, respectively. The number of heating regions 422 of the second heater unit 42 is greater than the number of heating regions 412 of the first heater unit 41. Hereinafter, the electrostatic chuck 1 will be described in detail.

  As shown in FIGS. 1 and 2, the electrostatic chuck 1 is a device that sucks and supports a semiconductor wafer 8 that is an object to be processed. The electrostatic chuck 1 includes a main body substrate 11, a metal base 12, a resin portion 13, and the like.

  In the present embodiment, the main body substrate 11 side is the upper side, and the metal base 12 side is the lower side. The vertical direction is a stacking direction of the main body substrate 11 and the metal base 12, and is a thickness direction of the main body substrate 11 and the metal base 12. The direction orthogonal to the vertical direction (thickness direction) is a direction (planar direction, plane direction) in which the electrostatic chuck 1 spreads in a plane.

  As shown in the figure, the main body substrate 11 is a member that supports the semiconductor wafer 8 by suction. The main body substrate 11 has a front surface (support surface) 111 and a back surface 112, and is formed in a disk shape. The surface (support surface) 111 of the main body substrate 11 is a surface that sucks and supports the semiconductor wafer 8. The main body substrate 11 is configured by laminating a plurality of ceramic layers (not shown). Each ceramic layer is made of an alumina sintered body containing alumina as a main component.

  An adsorption electrode 21 is disposed inside the main body substrate 11. The adsorption electrode 21 is disposed on substantially the same plane inside the main body substrate 11. The adsorption electrode 21 is formed in a circular shape in plan view. The adsorption electrode 21 generates an electrostatic attractive force by applying a DC high voltage. By this electrostatic attraction, the semiconductor wafer 8 is attracted and supported on the surface (support surface) 111 of the main body substrate 11. The adsorption electrode 21 is made of tungsten.

  A via 22 is disposed below the adsorption electrode 21 (on the metal base 12 side). The via 22 is formed in the vertical direction along the central axis of the main body substrate 11. The via 22 is connected to the adsorption electrode 21.

  Further, inside the electrostatic chuck 1, an internal hole 31 formed in the vertical direction from the back surface 122 of the metal base 12 toward the main body substrate 11 is provided. A cylindrical insulating member 311 is fitted in the internal hole 31. A metallized layer 23 is provided on the bottom surface of the internal hole 31. The metallized layer 23 is connected to the via 22. That is, the adsorption electrode 21 is connected to the metallized layer 23 through the via 22.

  The metallized layer 23 is provided with connection terminals 312. A terminal fitting 313 is attached to the connection terminal 312. The terminal fitting 313 is connected to a power supply circuit (not shown). The suction electrode 21 is supplied with electric power for generating an electrostatic attractive force via the connection terminal 312 or the like.

  In addition, a first heater unit 41 (main heater, main heater) including a heater electrode 411 is disposed inside the main body substrate 11. The first heater unit 41 is disposed below the adsorption electrode 21 inside the main body substrate 11. The first heater portion 41 is disposed on substantially the same plane inside the main body substrate 11. The heater electrode 411 is made of tungsten. Details of the first heater unit 41 will be described later.

  As shown in the figure, the resin portion 13 is disposed between the main body substrate 11 and the metal base 12. The resin part 13 is configured by laminating two resin layers (a first resin layer 131 and a second resin layer 132). The first resin layer 131 and the second resin layer 132 are resin films made of polyimide resin. On the 1st resin layer 131, the 2nd heater part 42 (heater for adjustment) which consists of the heater electrode 421 is provided.

  The second heater unit 42 is disposed between the first resin layer 131 and the second resin layer 132. That is, the second heater portion 42 made of the heater electrode 421 is disposed inside the resin portion 13. The second heater part 42 is arranged on substantially the same plane inside the resin part 13. The heater electrode 421 is made of a nickel alloy. Details of the second heater section 42 will be described later.

  The resin part 13 and the main body substrate 11 are joined via an adhesive layer 141 disposed therebetween. Moreover, the resin part 13 and the metal base 12 are joined via the contact bonding layer 142 arrange | positioned between both. The adhesive layers 141 and 142 are made of a flexible silicone resin adhesive that relaxes the difference in thermal expansion between the main body substrate 11 made of ceramic and the metal base 12 (adhesion made of polyimide resin when heat resistance is important). Agent).

  As shown in the figure, the metal base 12 is a metal cooling member (cooling plate) made of aluminum or an aluminum alloy. The metal base 12 has a front surface 121 and a back surface 122 and is formed in a disk shape. The metal base 12 is disposed below the main body substrate 11.

  Inside the metal base 12, a coolant channel 123 is provided for circulating a cooling medium (for example, a fluorinated liquid, pure water, etc.). The coolant channel 123 is disposed on substantially the same plane inside the metal base 12. The refrigerant flow path 123 is formed in a spiral shape in plan view. The refrigerant channel 123 is configured to introduce a cooling medium from one end thereof and to discharge the cooling medium from the other end.

  Although not shown, a cooling gas supply path serving as a supply path for a cooling gas such as helium for cooling the semiconductor wafer 8 is provided inside the electrostatic chuck 1. A plurality of cooling openings (not shown) formed by opening a cooling gas supply path and cooling gas supplied from the cooling openings are formed on the substrate surface (adsorption surface) 111 of the main body substrate 11. An annular cooling groove (not shown) formed so as to spread over the entire substrate surface (suction surface) 111 of the main body substrate 11 is provided.

  In the electrostatic chuck 1 having such a configuration, as shown in FIG. 3A, the first heater unit 41 has two divided heating regions 412. The 1st heater part 41 has the heating area | region 412a arrange | positioned inside and the heating area | region 412b arrange | positioned outside.

  In the heating area 412a and the heating area 412b, heater electrodes 411 are arranged on substantially the same plane. The long heater electrode 411 is disposed in each of the heating region 412a and the heating region 412b.

  As shown in FIG. 3B, the first heater section 41 is provided between the heating regions 412 (heating regions 412a, 412b), and a boundary region 413 that separates the heating regions 412 (heating regions 412a, 412b). Have The boundary region 413 of the first heater unit 41 is disposed so as to overlap with any one of the heating regions 422a to 422m (see FIG. 4) of the second heater unit 42 described later. In the present embodiment, most of the boundary region 413 of the first heater unit 41 is disposed so as to overlap with any one of the heating regions 422 a to 422 m of the second heater unit 42.

  As shown in FIG. 4, the 2nd heater part 42 has the divided | segmented 13 heating area | regions 422 (heating area | region 422a-422m). Although not shown, heater electrodes 421 are disposed on substantially the same plane in the heating regions 422a to 422m, respectively. The long heater electrode 421 is disposed in each of the heating regions 422a to 422m.

  The second heater unit 42 includes a boundary region 423 that is provided between the heating regions 412 (heating regions 422a to 422m) and separates the heating regions 412 (heating regions 422a to 422m). The boundary region 423 of the second heater unit 42 is disposed so as to overlap with any one of the heating regions 412a and 412b (see FIG. 3B) of the first heater unit 41. In the present embodiment, most of the boundary region 423 of the second heater unit 42 is disposed so as to overlap with any one of the heating regions 412 a and 412 b of the first heater unit 41.

  Moreover, the 1st heater part 41 and the 2nd heater part 42 are comprised so that it can control independently separately. The 1st heater part 41 is comprised so that the heater output of the heater electrode 411 can be independently controlled separately for every heating area | region 412 (heating area | region 412a, 412b). The 2nd heater part 42 is comprised so that the heater output of the heater electrode 421 can be independently controlled separately for every heating area | region 422 (heating area | region 422a-422m).

  As shown in FIG. 1, the heater electrode 411 disposed in each heating region 412 of the first heater unit 41 is electrically connected to the via 414, the driver (internal conductive layer) 415, and the via 416 provided in the main body substrate 11. Connected.

  Further, inside the electrostatic chuck 1, an internal hole 32 formed in the vertical direction from the back surface 122 of the metal base 12 toward the main body substrate 11 is provided. A cylindrical insulating member 321 is fitted in the internal hole 32. A metallized layer 417 is provided on the bottom surface of the internal hole 32. The metallized layer 417 is connected to the via 416. In other words, the heater electrode 411 is connected to the metallized layer 417 via the via 414, the driver 415, and the via 416.

  A connection terminal 322 is provided on the metallized layer 417. A terminal fitting 323 is attached to the connection terminal 322. The terminal fitting 323 is connected to a power supply circuit (not shown). Electric power for heating the heater electrode 411 is supplied to the heater electrode 411 of the first heater unit 41 via the connection terminal 322 or the like.

  In addition, although FIG. 1 demonstrated one heater electrode 411 among several heater electrodes 411 arrange | positioned at each heating area | region 412 (heating area | region 412a, 412b) of the 1st heater part 41, the other heater electrode 411 is demonstrated. Is the same. That is, as many internal holes 32 as the number of heater electrodes 411 are provided.

  As shown in the figure, the heater electrode 421 disposed in each heating region 422 of the second heater section 41 is electrically connected to a via 424 provided inside the resin section 13 and the adhesive layer 142.

  Further, inside the electrostatic chuck 1, an internal hole 33 formed in the vertical direction from the back surface 122 of the metal base 12 toward the main body substrate 11 is provided. A cylindrical insulating member 331 is fitted in the internal hole 33. A metallized layer 427 is provided on the bottom surface of the internal hole 33. The metallized layer 427 is connected to the via 424. That is, the heater electrode 421 is connected to the metallized layer 427 via the via 424.

  A connection terminal 332 is provided on the metallized layer 427. A terminal fitting 333 is attached to the connection terminal 332. The terminal fitting 333 is connected to a power supply circuit (not shown). Electric power for heating the heater electrode 421 is supplied to the heater electrode 421 of the second heater section 42 via the connection terminal 332 and the like.

  In addition, although FIG. 1 demonstrated one heater electrode 421 among the plurality of heater electrodes 421 arranged in each heating region 422 (heating regions 422a to 422m) of the second heater unit 42, other heater electrodes 421 are described. Is the same. That is, as many internal holes 33 as the number of heater electrodes 421 are provided.

  Further, the driver (internal conductive layer) is provided below the heater electrode 421 in the same manner as the driver (internal conductive layer) 415 is formed below the heater electrode 411 of the first heater unit 41 for the second heater portion 42. By forming, the terminal position can be moved to an arbitrary position.

Next, a method for manufacturing the electrostatic chuck 1 of this embodiment will be described.
First, the main body substrate 11 is produced. Specifically, alumina powder (average particle size 0.4 μm) having a purity of 99.9%, a resin, a plasticizer, a dispersant, a solvent, and the like are mixed to prepare a slurry. This slurry is formed into a sheet shape by a doctor blade method or the like. Thereby, the green sheet which has an alumina as a main component is produced. In the present embodiment, a plurality of green sheets to be the main body substrate 11 are produced.

  Further, the above-described alumina powder for green sheet for enhancing the adhesion to the main body substrate 11 is mixed with the tungsten powder, and further, a resin, a solvent, and the like are mixed to prepare a conductor paste.

  Next, a space serving as an internal hole 31, a space serving as a cooling gas flow path such as a cooling gas supply path, and a through hole serving as vias 22, 414, and 416 are formed in a plurality of necessary positions on the plurality of green sheets. . Then, the conductor paste is filled into the through holes formed at the positions to be the vias 22, 414, and 416. Further, a conductor paste is applied to the positions where the adsorption electrode 21, the heater electrode 411 of the first heater section 41, and the driver 415 are formed in a plurality of green sheets by a method such as screen printing.

Next, a plurality of ceramic green sheets are aligned with each other, stacked, and thermocompression bonded to obtain a stacked body. The laminate is cut into a predetermined shape. Then, degrease the stack in an N ₂ atmosphere. Thereafter, firing is performed at 1600 ° C. in a humidified N ₂ / H ₂ atmosphere. Thereby, the main body substrate 11 provided with the electrode 21 for adsorption, the heater electrode 411 of the first heater unit 41, and the like is obtained.

  Subsequently, the resin part 13 is produced. Specifically, as shown in FIG. 5A, a through hole to be a via 424 is formed in a required portion in the first resin layer 131 which is a resin film made of polyimide resin. Then, the through-hole is filled with a conductor paste. Thereby, a via 424 is formed. Thereafter, a thin metal sheet 400 made of a nickel alloy is bonded onto the first resin layer 131.

  Next, as shown in FIG. 5B, in order to form a wiring pattern of the heater electrode 421 of the second heater section 42, a resist film (not shown) is formed on the surface of the metal sheet 400 and patterned into a wiring shape. To do. Then, a chemical etching process is performed to process the metal sheet 400 into a wiring shape. Thereafter, the resist film is peeled off. As a result, the heater electrode 421 of the second heater section 42 is formed on the first resin layer 131.

  Next, as shown in FIG. 6A, a second resin layer 132, which is a resin film made of polyimide resin, is placed on the first resin layer 131 on which the heater electrode 421 of the second heater section 42 is formed. Then, as shown in FIG. 6B, the first resin layer 131 and the second resin layer 132 are pressure-bonded. Thereby, the resin part 13 provided with the heater electrode 421 and the like of the second heater part 42 is obtained.

  Next, the metal base 12 and the resin portion 13 are joined (adhered) with an adhesive (adhesive layer 142) made of silicone resin. Similarly, the main body substrate 11 and the resin portion 13 are joined (adhered) with an adhesive (adhesive layer 141) made of silicone resin. Thus, the electrostatic chuck 1 is obtained.

Next, the effect of the electrostatic chuck 1 of this embodiment will be described.
In the electrostatic chuck 1 of this embodiment, a first heater part 41 is provided on the main body substrate 11, and a second heater part 42 is provided on the resin part 13. By adopting a two-layered heater, the variation in the temperature distribution of the support surface 111 caused by the first heater part 41 provided on the main body substrate 11 is adjusted by the second heater part 42 provided on the resin part 13 to be uniform. Can be In particular, since the number of the heating regions 422 (422a to 422m) of the second heater unit 42 is larger than the number of the heating regions 412 (412a, 412b) of the first heater unit 41, variation in the temperature distribution of the support surface 111 is caused. It can be finely adjusted and the temperature distribution can be made uniform with higher accuracy. Thereby, the temperature distribution of the support surface 111 of the main body substrate 11 can be made uniform. And the temperature dispersion | variation of the semiconductor wafer (to-be-processed object) 8 supported by the support surface 111 of the main body board | substrate 11 can also be reduced.

  One heater (first heater portion 41) is provided on the main body substrate 11, and the other heater (second heater portion 42) is provided on the resin portion 13. In particular, the second heater portion 42 is provided in the resin portion 13 having a Young's modulus larger than that of the ceramic constituting the main body substrate 11 and less stress generated by deformation due to heat. Therefore, it is possible to suppress the generation of thermal stress due to the difference in heat generation temperature between the heaters and the cracking of the main body substrate 11 accompanying the conventional heat generation, and it is possible to improve durability and reliability. Thereby, even if it is a case where it uses for a long time at high temperature, durability and reliability are fully securable.

  Further, in the electrostatic chuck 1 of the present embodiment, the first heater unit 41 further includes a boundary region 413 that is provided between the heating regions 412 and separates the heating regions 412. And when it sees from the thickness direction of the main body board | substrate 11, the boundary area | region 413 of the 1st heater part 41 is arrange | positioned so that the heating area | region 422 of the 2nd heater part 42 may overlap. Therefore, the variation in the temperature distribution of the support surface 111 generated in the boundary region 413 of the first heater unit 41 of the main body substrate 11 can be adjusted and uniformed by the heating region 422 of the second heater unit 42 of the resin unit 13. it can.

  Thus, according to the present embodiment, the temperature distribution of the support surface 111 of the main body substrate 11 that supports the semiconductor wafer (object to be processed) 8 can be made uniform, and the durability and reliability can be improved. An electrostatic chuck 1 can be provided.

In this embodiment, the main body substrate 11 is manufactured by the above-described method, but the main body substrate 11 can also be manufactured by other methods. For example, a 99.9% pure alumina powder (average particle size 0.4 μm), a resin, a dispersant, and the like are mixed to prepare a slurry. This slurry is spray-dried by a spray dryer to produce alumina granulated granules. Alumina granulated granules are filled into a mold and press-molded. A molybdenum metal wire mesh for the adsorption electrode 21 and a molybdenum heating element for the heater electrode 411 of the first heater section 41 are placed on the obtained molded body, and alumina granulated granules are filled thereon, and then pressed again. Mold. The obtained molded body is set in a carbon sheath and fired by a hot press method (N ₂ atmosphere, pressure: 10 MPa). Thereby, the main body substrate 11 provided with the adsorption electrode 21, the heater electrode 411 of the first heater portion 41, and the like can be manufactured.

(Experimental example)
In this experimental example, a plurality of electrostatic chucks (Example 1, Comparative Examples 1 and 2) were prepared, and the performance (surface temperature distribution, reliability) of each electrostatic chuck was evaluated.

  The electrostatic chuck of Example 1 has the same configuration as the electrostatic chuck of Embodiment 1 described above. In other words, a first heater portion that is a main heater is provided on the main body substrate, and a second heater that is an adjustment heater is provided on the resin portion.

  The electrostatic chuck of Comparative Example 1 is different from the electrostatic chuck of Embodiment 1 described above in that the second heater part is not provided in the resin part. The electrostatic chuck of Comparative Example 2 is that the first heater part and the second heater part are provided in order from the top on the main body substrate, and the second heater part is not provided on the resin part. Different from chuck.

  The surface temperature distribution was evaluated by increasing the surface temperature (support surface) of the main substrate of the electrostatic chuck and measuring the temperature distribution on the support surface, specifically the difference between the maximum and minimum temperatures (temperature difference). . In addition, the set temperature of a support surface was made into two types, 70 degreeC and 120 degreeC.

  When the set temperature of the support surface was 70 ° C. (120 ° C.), the electrostatic chuck was set in a vacuum chamber, and cooling water at 20 ° C. was allowed to flow through the metal-based coolant channel. Then, the heater outputs of the two heating regions of the first heater unit, which is the main heater, were adjusted so that the maximum temperature of the support surface was 65 ° C. (115 ° C.). The temperature distribution on the support surface was measured using an infrared camera. Then, using the second heater part, which is an adjustment heater, the temperature of the maximum temperature of the support surface is increased by 5 ° C., the temperature of the other portions is increased by 5 ° C. + α, and the maximum temperature of the support surface is 70 ° C. ( 120 ° C.), and the heater output of each of the 13 heating regions of the second heater unit was adjusted so that the entire support surface had a uniform temperature. The electrostatic chuck of Comparative Example 1 was adjusted so that the maximum temperature of the support surface was 70 ° C. (120 ° C.) with only the first heater portion.

  Evaluation of reliability is performed by repeatedly adjusting the temperature of the surface (support surface) of the main body substrate of the electrostatic chuck at 30 ° C. and 120 ° C. (30 ° C. → 120 ° C. → 30 ° C. → 120 ° C ....) 3000 times The state of the main body substrate and the resin part after the thermal cycle test was evaluated by ultrasonic flaw detection or the like.

Table 1 shows the evaluation results. As can be seen from the table, the electrostatic chuck of Example 1 has a smaller temperature variation on the support surface than the electrostatic chucks of Comparative Examples 1 and 2, and the temperature distribution on the support surface can be made uniform. Further, the electrostatic chuck of Example 1 had no abnormality after the thermal cycle test, but the electrostatic chuck of Comparative Example 2 had cracks in the main substrate after the thermal cycle test.

  From the above results, the electrostatic chuck of the present invention is provided with the first heater part as the main heater on the main body substrate, the second heater part as the adjustment heater on the resin part, and the heating area of the second heater part. By increasing the number of the heaters more than the number of heating areas of the first heater unit, the temperature distribution on the support surface of the main body substrate that supports the object to be processed can be made uniform, and the durability and reliability can be improved. I found out.

(Other embodiments)
It goes without saying that the present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the present invention.

  (1) In the above-described embodiment, the first heater unit is divided into two heating regions and the second heater unit is divided into 13 heating regions. However, the number of heating regions is not limited to this. Various modifications are possible. The more the heating area of the second heater part, which is an adjustment heater, increases, the more the temperature distribution variation of the support surface of the main body substrate is adjusted by the second heater part, and the uniformity of the temperature distribution of the support surface is improved. it can.

DESCRIPTION OF SYMBOLS 1 ... Electrostatic chuck 11 ... Main body substrate 111 ... Support surface 12 ... Metal base 121 ... Front surface 122 ... Back surface 13 ... Resin part 21 ... Electrode for adsorption 41 ... 1st heater part 411 ... Heater electrode 412 ... Heating area 42 ... 2nd Heater part 421 ... heater electrode 422 ... heating area

Claims (2)

A metal base having a front surface and a back surface;
A main body substrate which is disposed on the surface side of the metal base and has a support surface for supporting an object to be processed, and is made of ceramic;
An adsorption electrode provided on the main substrate for adsorbing the workpiece;
A resin portion disposed between the metal base and the main body substrate;
A first heater portion provided on the main body substrate and including a heater electrode;
A second heater part made of a heater electrode provided in the resin part,
Each of the first heater part and the second heater part has a plurality of heating regions,
The electrostatic chuck according to claim 1, wherein the number of the heating regions of the second heater unit is greater than the number of the heating regions of the first heater unit.   The first heater portion is provided between the heating regions, further includes a boundary region that separates the heating regions, and when viewed from the thickness direction of the main body substrate, the boundary of the first heater unit The electrostatic chuck according to claim 1, wherein the region is disposed so as to overlap the heating region of the second heater unit.