JP2003264223A - Electrostatic chuck component, electrostatic chuck device, and manufacturing method for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic chuck plate and an electrostatic chuck device which have high in durability and are of long lives and can be repaired inexpensively and easily even when broker. <P>SOLUTION: The electrostatic chuck plate is formed by stacking a metallic layer to serve as an internal electrode for electrostatic adsorption and a ceramic dielectric layer to serve as an electrostatic adsorptive face sequentially on a ceramic plate. The electrostatic chuck device utilizes the electrostatic chuck plate. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic chuck device used in a semiconductor manufacturing process or the like, and is particularly suitable for its recycling.

[0002]

2. Description of the Related Art In a semiconductor manufacturing apparatus for processing by generating plasma such as dry etching or CVD, an object to be processed such as a silicon wafer is securely held in the apparatus.
Needs to be fixed. Conventionally, mechanical chucks or vacuum chucks have been adopted as a method of fixing a silicon wafer. However, in recent years, an electrostatic chuck for attracting and fixing a silicon wafer by electrostatic force has become popular because of advantages such as maintaining temperature uniformity of the silicon wafer and reducing particles.

A schematic side sectional view of a general electrostatic chuck device is shown in FIG. 1. The electrostatic chuck plate has a lower insulator layer 3 having a thickness of several mm or less and an upper part serving as an electrostatic attraction surface. It has a three-layer structure of a dielectric layer 1 and an internal metallic electrode layer 2 which is embedded so as to be sandwiched between the dielectric layer 1 and the internal metallic electrode layer 2. This is mounted on a metal base plate 4 having a water cooling groove 5 or other water cooling mechanism. There is. Then, a DC voltage 8 is applied between the silicon wafer 6 placed on the surface of the upper dielectric layer and the power supply terminal 7 taken out to the internal electrode layer 2 to electrostatically adsorb the silicon wafer 6. You can Further, in the above description, the structure of the internal electrode is a unipolar type, but there is also a bipolar type electrostatic chuck in which the internal electrode is divided into two and a DC voltage is applied between the two electrodes.

The lower insulating layer 3 and the upper dielectric layer 1 are usually made of the same material, and a resin film such as polyimide or epoxy, or a ceramic film such as alumina or aluminum nitride is often used. The ceramic film is roughly classified into a sintered formed body and a thermal spray formed body.

[0005]

As an example of an electrostatic chuck device using a resin film such as polyimide for the upper dielectric layer which becomes the electrostatic attraction surface, Japanese Patent No. 2130375 is cited. This electrostatic chucking device attaches a polyimide film on a metal base plate using an adhesive,
Further, the internal metallic electrode layer and the upper polyimide dielectric layer serving as an electrostatic attraction surface are similarly attached with an adhesive.

Such an electrostatic chuck device made of a resin film has excellent insulation properties and film thickness uniformity. When the resin film is damaged, the electrostatic chuck device can be reused by replacing it. It is possible. However, the resin film is liable to deteriorate due to various reactions caused by plasma during the wafer process, and thus has poor durability, and is very thin and easily scratched.

Further, in the upper dielectric layer which becomes the electrostatic attraction surface,
As an example of an electrostatic chuck device using a ceramics sintered body such as alumina, Japanese Patent Laid-Open No. 11-312729 and Japanese Patent No. 2694668 can be cited. These electrostatic chuck devices have a structure in which an internal metallic electrode layer is sandwiched between alumina ceramics and embedded, and a plate integrated by sintering is attached to a metal base plate by brazing or the like. The electrostatic chuck device made of such a ceramic sintered body has excellent plasma resistance and has a longer life than the electrostatic chuck device made of a resin film. However, since the ceramics sintered body is very expensive, if it is damaged once and the ceramics plate is replaced with a new one and the electrostatic chuck device is reused, the manufacturing cost becomes very high.

Further, as an example of an electrostatic chuck device using a ceramic sprayed film of alumina or the like as an upper dielectric layer which becomes an electrostatic attraction surface, Japanese Patent No. 1439076 and Japanese Patent Laid-Open No.
No. 01-203258 is listed. This electrostatic chuck device has a structure in which a lower alumina ceramics insulating layer, an internal metallic electrode layer, and an upper alumina ceramics dielectric layer are sequentially formed on a metal base plate by a thermal spraying method. Such an electrostatic chuck device made of a ceramic sprayed film has a long manufacturing life because it has a lower manufacturing cost and an equally high plasma resistance as compared with an electrostatic chuck device made of a ceramic sintered body. However, since the thermal spray coating is directly formed on the metal base plate, if the thermal spray coating is damaged, it is very difficult to re-use the electrostatic chuck device by re-attaching.

As described above, there is currently no electrostatic chuck device which has a long life and is low in manufacturing cost when it is damaged and can be reused. Therefore, an object of the present invention is to provide an electrostatic chuck device which has high durability and long life, and can be easily reused at low cost even if it is damaged.

[0010]

In order to achieve the above object, the present invention provides an electrostatic chuck plate, an electrostatic chuck device including the same, and a method for manufacturing the same, which will be described below. .

That is, a metal layer serving as an internal electrode for electrostatic attraction and a ceramic dielectric layer serving as an electrostatic attraction surface are sequentially laminated on a ceramic plate to form the metal layer and the ceramic layer. An electrostatic chuck plate, characterized in that the dielectric layer is formed by a thermal spraying method,
Further, the ceramic dielectric layer is subjected to a sealing treatment made of an organic or inorganic resin compound, and in the electrostatic chuck plate, the surface of the ceramic dielectric layer is An electrostatic chuck plate characterized by being partially thinly shaved and subjected to dimple processing to form a large number of irregularities,
Further, an electrostatic chuck device in which these electrostatic chuck plates are pasted on a metal base plate, and a metal is sprayed onto the ceramic plate to have a diameter smaller than that of the ceramic plate to form an internal electrode for electrostatic attraction. A step of forming a metallic layer, further spraying ceramics so as to cover the metallic layer to form a ceramics dielectric layer serving as an electrostatic attraction surface, and a ceramics dielectric layer serving as an electrostatic attraction surface Mechanically grinding and / or polishing the surface to adjust the flatness, surface roughness, etc., and applying an uncured liquid resin compound to the surface of the ceramic dielectric layer, or the electrostatic chuck plate body to the liquid resin compound. And leave it under vacuum for a sealing treatment step to solidify the resin compound, and to clean the surface of the ceramics dielectric layer that will become the electrostatic attraction surface. Scraping partially thinned by a method such as preparative, it is a manufacturing method of the electrostatic chuck plate which comprises a step of performing dimpled to form multiple irregularities.

The electrostatic chuck plate of the present invention can be used by adhering it to a metal base plate by brazing or the like in the same manner as in the conventional electrostatic chuck device made of a ceramic sintered body. Therefore, if it is damaged, the electrostatic chuck device can be easily reused by reattaching the electrostatic chuck plate. Further, since the ceramics sprayed film is used on the electrostatic attraction surface, the manufacturing cost is lower and the durability is longer than the case where the ceramics sintered body is used, and it is possible to use for a long time.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a schematic side sectional view showing an example of the electrostatic chuck device according to the present invention. The electrostatic chuck plate 10 of the present invention can be used for the water cooling groove 15 by a method such as brazing.
It is mounted on a metal base plate 14 having a water cooling mechanism such as. In the electrostatic chuck plate 10 of the present invention, a metallic layer 12 serving as an internal electrode for electrostatic attraction and a ceramic dielectric layer 11 serving as an electrostatic attraction surface are sequentially formed on a sintered ceramic plate 13 by a thermal spraying method. Has been done. An example of the manufacturing method will be described below.

A metallic material is sprayed onto a disc-shaped sintered ceramics plate 13 having a thickness of about 1 to 10 mm,
A metallic layer 12 which will be an internal electrode for electrostatic attraction is formed. At this time, masking is applied in advance to prevent unnecessary portions from being sprayed in order to make the spraying range of the metallic layer smaller than the diameter of the sintered ceramics plate. Although an example of an electrostatic chuck having a unipolar electrode shape is shown here, a bipolar electrostatic chuck can be similarly prepared. Then, the ceramic dielectric layer 11 is sprayed so as to cover the metallic layer 12 to form an electrostatic attraction surface. Then, the surface of the upper ceramics dielectric layer 11 is subjected to mechanical processing such as grinding, lapping, polishing, etc., and dimensions such as film thickness, flatness and surface roughness are adjusted. At that time, it is preferable that the flatness is 20 μm or less and the surface roughness Ra is 0.1 to 5.0 μm or less. The materials for the sintered ceramics plate 13 and the materials for forming the metallic layer 12 and the ceramics dielectric layer 11 include, but are not limited to, those shown below. That is, the material of the sintered ceramics plate 13 is Al2O3,
A material mainly composed of a highly insulating material such as AlN or SiC can be used, and its thickness is preferably about 1 to 15 mm. Also,
As a material for forming the metallic layer 12, W, Al, C
Thermally sprayable metallic materials such as u, Ni and Mo can be used alone or as an alloy containing them, and the thickness thereof is 5 to 5.
About 300 μm is preferable. Further, as a material for forming the ceramics dielectric layer 11, Al2O3, AlN, S
iC and the like can be increased, and ones containing these or a main component can be used, and the thickness thereof is preferably about 50 to 500 μm.

The electrostatic chuck plate 10 produced as described above is attached onto the metal base plate 14 by using a metal brazing material, a resin adhesive or the like. The material of the metal base plate is mainly made of Al, Cu or an alloy containing these metals.

Further, the upper ceramics dielectric layer 11 of the electrostatic chuck plate 10 formed as described above.
Since it has pores peculiar to the thermal spray coating, it is desirable to perform a sealing treatment, and if necessary, it may be performed plural times before or after machining. The method of sealing treatment may be as follows. That is, after coating the uncured liquid resin compound on the surface of the upper ceramics dielectric layer 11, the electrostatic chuck plate 10 is left in a vacuum furnace for several tens of minutes or longer, and then at room temperature or several tens to 200 in the atmosphere.
The resin is solidified by heating to about ℃.

Although not shown in FIGS. 1 and 2, the electrostatic chuck is often provided with a pipe for introducing a cooling gas into the gap between the silicon wafer and the suction surface. He is generally used as the cooling gas, and it has the purpose of improving the heat transfer between the silicon wafer and the electrostatic chuck by filling the gap between the silicon wafer and the suction surface with the gas. In the electrostatic chuck according to the present invention, in order to provide a gap between the silicon wafer and the electrostatic chuck suction surface, dimple processing is performed as necessary,
An example of a schematic side sectional view thereof is shown in FIG. 3a, and a schematic plan view thereof is shown in FIG. 3b. 24 is a gas introduction pipe, 2
Reference numerals 1 and 23 are convex portions of the dimples, 22 is a concave portion filled with gas, and other symbols are the same as those in FIG. Widths 1 to 2 that form dimple projections on the surface of the ceramic dielectric layer 11
The outer peripheral portion 24 having a diameter of about 0 mm and the circular portion 21 having a diameter of about 1 to 10 mm, in which a plurality of the outer peripheral portions 24 are arranged substantially evenly, are masked, and the remaining portion is subjected to blasting or the like at 5 to 50 μm
It is thinly shaved so that a step is formed to some extent to form a concave portion 22 in a gap filled with gas. The size and number of the convex portions are adjusted so that the area of the portion that comes into contact with the silicon wafer as the convex portion of the dimple is about 20 to 80% of the total area including the concave portion. Further, although the shape of the convex portion of the dimple is circular in the above example, it may be any shape such as a quadrangle or a triangle.

[0018]

Example 1 One surface of an alumina sintered ceramics plate having a thickness of 2 mm and a diameter of 200 mm was roughened by blasting, and a surface having a width of 2 mm was masked at the outer peripheral portion and tungsten was 50 μm thick on the roughened surface. Plasma sprayed so that Further, the surface of the tungsten layer was blasted in the same manner as described above to roughen the surface, and then alumina having a purity of 99.9% was plasma-sprayed on the surface of the alumina layer so as to conceal much of the tungsten layer so that the thickness was 450 μm. In order to carry out the sealing treatment at this stage, uncured organic silicon resin is applied to the surface of the alumina dielectric layer of the electrostatic chuck plate, then left in a vacuum furnace for 30 minutes, and further in the air at 80 ° C.
The resin was left to stand in the drying oven for about 2 hours to solidify the resin. After that, the surface of the alumina sprayed layer was ground to a thickness of 250
The surface roughness Ra was set to 0.2 μm or less by performing polishing so that the surface roughness Ra was 0.2 μm or less.

The electrostatic chuck plate prepared as described above was attached to a metal base plate made of Al using a metal brazing material to complete an electrostatic chuck device.

[0020]

[Embodiment 2] The electrostatic chuck plate produced in the same manner as in Embodiment 1 was subjected to dimple processing. Around the outer surface of the alumina sprayed layer having a width of 8 mm and a plurality of regularly arranged circular parts having a diameter of 4 mm are masked so as to occupy 65% of the surface area of the alumina sprayed layer, and the remaining part is blasted to a depth of 20 μm. I scraped off and made a step. The electrostatic chuck plate on which the dimples were formed was also attached to the metal base plate made of Al in the same manner as in Example 1 to complete the electrostatic chuck device.

Both the electrostatic chuck devices of Examples 1 and 2 produced as described above were able to adsorb a silicon wafer with an adsorption force of 15 g / cm 2 or more by applying a DC voltage of 1.0 kV. . Further, since the electrostatic attraction surface is a ceramic sprayed layer, it has excellent plasma resistance and has a long life. Furthermore, by replacing the electrostatic chuck plate part newly, it is possible to easily exhibit the same performance as a new product, and the manufacturing cost due to this replacement is higher than that of the ceramic chuck integrated electrostatic chuck plate. Was also very low.

[0022]

As described above, the electrostatic chuck plate and the electrostatic chuck device according to the present invention are manufactured by sequentially laminating the metallic electrode layer and the ceramic dielectric layer on the ceramic plate by the thermal spraying method. As a result, the electrostatic chuck device has high durability and long life, but if it is damaged, the electrostatic chuck device can be re-used easily and at low cost by newly replacing the electrostatic chuck plate.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a conventional electrostatic chuck device.

FIG. 2 is a schematic cross-sectional view showing an example of an electrostatic chuck device of the present invention.

FIG. 3a is a schematic sectional view showing an example of an electrostatic chuck plate on which a dimple process of the present invention has been applied.

FIG. 3b is a schematic plan view showing an example of the electrostatic chuck plate on which the dimple processing of the present invention has been applied.

[Explanation of symbols]

1: Upper dielectric layer 2: Internal metallic electrode layer 3: Lower insulating layer 4: Metal base plate 5: Water cooling groove 6: Silicon wafer 7: Power supply terminal 8: DC voltage 10: Electrostatic chuck plate 11: Ceramics dielectric Layer 12: Metallic layer 13:
Sintered ceramics plate 14: metal base plate 15: water cooling groove 21: dimple convex portion 22: dimple concave portion 23: dimple outer peripheral portion 24: gas introduction pipe

Claims (6)

[Claims] 1. An electrostatic chuck plate comprising a ceramic plate and a metallic layer serving as an internal electrode for electrostatic attraction, and a ceramic dielectric layer serving as an electrostatic attracting surface, which are sequentially laminated. 2. The electrostatic chuck plate according to claim 1, wherein the metallic layer and the ceramic dielectric layer are layers formed by a thermal spraying method. 3. The electrostatic chuck plate according to claim 1, wherein the ceramic dielectric layer has a sealing treatment made of an organic or inorganic resin compound. Chuck plate. 4. The electrostatic chuck plate according to claim 1, wherein the surface of the ceramic dielectric layer is partially thinly shaved and dimple processing is performed to form a large number of irregularities. The electrostatic chuck plate according to. 5. An electrostatic chuck device comprising the electrostatic chuck plate according to claim 1 on a metal base plate. 6. A metal layer is sprayed on the ceramic plate so as to have a diameter smaller than that of the ceramic plate to form a metal layer serving as an internal electrode for electrostatic attraction, and the metal layer is further covered thereon. To spray the ceramics to form a ceramics dielectric layer serving as an electrostatic attraction surface, and to mechanically grind and / or polish the ceramics dielectric layer serving as an electrostatic attraction surface to obtain flatness and surface roughness. Etc., and applying an uncured liquid resin compound to the surface of the ceramic dielectric layer, or immersing the electrostatic chuck plate body in the liquid resin compound and leaving it under vacuum, and then sealing the resin compound to solidify. The hole treatment step and the step of performing a dimple process for forming a large number of irregularities by partially shaving the surface of the ceramic dielectric layer, which is the electrostatic attraction surface, by a method such as blasting. Method of manufacturing an electrostatic chuck plate, wherein Mukoto.