JP2859993B2 - Manufacturing method of electrostatic chuck - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electrostatic chuck, and more particularly to a method for manufacturing an electrostatic chuck in which electrode materials are prevented from being distorted, cracked or warped.

[0002]

2. Description of the Related Art The processes of manufacturing semiconductors and liquid crystals, and processes such as dry etching, ion implantation, and vapor deposition of semiconductor devices, are becoming more automated and dry. As the diameter of a substrate such as a silicon wafer or glass is increased, and the circuit is highly integrated and miniaturized, positional accuracy at the time of patterning is becoming increasingly important.

[0003] Therefore, a vacuum chuck is generally used as a chucking method used for transporting and adsorbing and fixing a substrate, which is used to form several to several tens of holes in a chuck plate. However, the pressure is reduced from this hole to fix the substrate by suction, but this vacuum chuck cannot be used because there is no pressure difference under vacuum conditions,
This is disadvantageous in that when the substrate is sucked under non-vacuum, the suction portion is locally sucked, and the substrate is partially distorted, so that high-precision alignment cannot be performed. It is considered unsuitable for liquid crystal manufacturing processes.

[0004] For this reason, attention has been paid to an electrostatic chuck that transports a substrate by using static electricity or fixes it by suction.
Although the electrostatic chuck has begun to be used, its electrode material is made of an insulating dielectric because its internal electrode is made of a metal such as tungsten, molybdenum, silver-palladium, gold, silver, or an alloy thereof. There was a disadvantage that the adhesion to the layer was poor, and peeling and cracking occurred.

[0005]

Therefore, it has been proposed to improve the adhesion of this electrostatic chuck by adding a titanium nitride powder to a tungsten or molybdenum powder (Japanese Patent Application Laid-Open No. Hei 3-62464). See)
Even this still has insufficient adhesiveness, which causes problems such as heating of the electrostatic chuck itself due to an increase in electrode resistance, and furthermore, internal stress is applied, and distortion and cracking are likely to occur. There is also a disadvantage.

[0006] The present invention relates to a manufacturing method of an electrostatic chuck which solves such a disadvantage, this method of manufacturing an electrostatic chuck having an electrode layer made of tungsten and the insulating dielectric layer and baking Insulating dielectric layer
Green sheet from ceramic slurry
Tungs that are fired on this green sheet to form an electrode layer
After forming a paste layer containing ten compounds,
Another green sheet was laminated on the strike layer and integrated
Chi, firing this, is characterized in that reduction. The insulating dielectric layer is made of aluminum nitride.
Is preferred.

That is, the present inventors have conducted various studies on a method of manufacturing an electrostatic chuck without the disadvantages described above, and as a result, have found that a paste made of a tungsten compound such as tungstic acid is used as an electrode material of the electrostatic chuck. then, since the tungsten compound is <br/> easily and firmly bonded to the insulating dielectric layer, to relieve thermal stress generated between the insulating dielectric layer and the internal electrode, distortion or cracking, warping In addition, the generation of such a tungsten compound is prevented, and when this tungsten compound is fired and reduced, it eventually becomes metallic tungsten, so that the internal resistance does not increase. Therefore, an electrostatic chuck having excellent physical properties can be easily obtained. And that it can be manufactured with good workability, and conducted research on the types of insulating dielectrics and tungsten compounds used here. Umate has led to the completion of the present invention. This is described in more detail below.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a manufacturing method of an electrostatic chuck, this is a fired to insulating dielectric layer ceramic
A green sheet is prepared from the mixture slurry, and
After forming a paste layer containing a tungsten compound to be an electrode layer, another green sheet is further formed thereon.
This is characterized by stacking, firing and reducing, but this makes it easy to produce an electrostatic chuck that does not generate distortion, cracks, warpage, etc., and does not generate heat itself. Has the advantage that it can be obtained with good workability.

The present invention relates to a method for manufacturing an electrostatic chuck. The electrostatic chuck has an insulating dielectric layer and an electrode material made of tungsten. The insulating dielectric layer is made of aluminum nitride. , Alumina, quartz,
It is made of zirconia, boron nitride, sialon, or the like. In addition, aluminum nitride among these was not conventionally preferable because of its poor adhesiveness to the electrode material, but it is strongly bonded to the tungsten compound used in the present invention, Conductivity,
This is considered optimal in the method of the invention because of its excellent insulation.

The thickness of the insulating dielectric layer is thin because the electrostatic voltage of the electrostatic chuck is proportional to the square of the applied voltage and inversely proportional to the square of the thickness of the insulating dielectric layer for adsorbing the substrate. The thinner the thickness, the stronger the electrostatic force, but it is necessary to set the range of 100 μm to 20 mm because it is required to be easy to process and to prevent discharge from occurring between the substrate and the electrode.

The internal electrode layer used in the method of manufacturing an electrostatic chuck according to the present invention is made of tungsten, and may be of a monopolar type having one of the electrodes as a substrate or a bipolar type having no electrode. Preferably, the thickness of this electrode layer may be appropriately determined within the allowable range of the withstand voltage of the internal electrode layer.
The tungsten electrode material is produced by firing and reducing a tungsten compound. Examples of the tungsten compound include tungstic acid, tungsten oxide, and ammonium tungstate.

In the manufacture of the electrostatic chuck according to the present invention, a green sheet having a desired thickness is formed from a ceramic slurry such as aluminum nitride with a doctor blade or the like, and a paste made of a compound such as tungstic acid is screen-printed on the green sheet. The internal electrode layer is formed by printing with a method such as the above. Then, an insulating dielectric layer made of aluminum nitride is laminated thereon, and then pressed and integrated, and then the laminated body is placed in an incinerator and placed in an inert atmosphere at 1,000 to 2,000 ° C. for 0.5 to 10 minutes. The heating and baking may be performed for a period of time, according to which the tungstic acid is reduced to metal tungsten, which forms an electrode body.

The thus obtained electrostatic chuck is
Since the insulating dielectric layer and the internal electrode layer are completely integrated and firmly adhered, stress relaxation and thermal conductivity are excellent, and internal resistance does not increase, and distortion, cracking, warping, etc. This is advantageous because it does not occur.

[0014]

Next, examples of the present invention and comparative examples will be described. Example 100 parts by weight of a mixture of 95% by weight of aluminum nitride powder and 5% by weight of yttria were added with 10 parts by weight of butyral resin, 50 parts by weight of trichloroethylene, 8 parts by weight of ethanol, and 2 parts by weight of dioctyl phthalate.
A slurry was prepared by mixing for a period of time, and the slurry was subjected to a defoaming machine to partially scatter the solvent to obtain a viscosity of 30,000 cps.

A green sheet having a thickness of 1.5 mm is made from the slurry by using a doctor blade, a single disk having a diameter of 180 mm is cut out from the slurry, and a green sheet having a thickness of 5 mm is separately formed. 1 disk was cut out. Next, a tungstate paste is printed concentrically at 1 mm intervals on a single green sheet disk having a thickness of 5 mm by a screen printing method using a 400-mesh screen to form a bipolar internal electrode. A green sheet disk having a thickness of 1.5 mm was placed on the plate and pressed with a press machine at 100 ° C. and 5 kg / cm ² for 50 minutes to laminate them.

Next, this laminate is fired at 1,850 ° C. for 3 hours in an atmosphere of 20% hydrogen gas and 80% nitrogen gas,
Nickel plating and gold plating were applied to a portion where the internal electrode was taken out, and two lead wires were soldered to this to make an electrostatic chuck.

When a DC voltage of 1 KV was applied between the lead wires of the thus obtained electrostatic chuck, a 6-inch silicon substrate was completely adsorbed. The SiO ₂ film was plasma etched at 140 ° C. using CF ₄ gas, and the etching distribution at that time was measured. As a result, the distribution was almost uniform in the range of ± 1.0% over the entire substrate.

Comparative Example For comparison, an electrostatic chuck was prepared in the same manner as described above except that the internal electrode in the above-described example was formed using a molybdenum paste. Some unbonded parts were also observed.

[0019]

[Effect of the Invention The present invention relates to a manufacturing method of an electrostatic chuck, this is the manufacturing method of an electrostatic chuck having an electrode material made of an insulating dielectric layer and tungsten as described above, firing the insulating ceramic as the sex dielectric layer
A green sheet from the slurry
A pace containing a tungsten compound that becomes an electrode layer by firing
After forming a green layer, another green sheet
Sorted laminated, firing this, but those characterized by comprising as reduced to the electrode material, tungsten compound according to this easily and strongly bonded with the insulating dielectric layer,
An electrostatic chuck that has excellent physical properties without distortion, cracking, warping, etc., because it reduces the thermal stress generated between the insulating dielectric layer and the internal electrode, and this electrode material does not increase the internal resistance. Can be manufactured easily and with good workability.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenichi Arai 2-3-1-1, Isobe, Annaka-shi, Gunma Shin-Etsu Chemical Co., Ltd.Precision Functional Materials Laboratory (72) Inventor Yoshihiro Kubota Isobe, Annaka-shi, Gunma No. 2-13-1 Shin-Etsu Chemical Co., Ltd. Precision Functional Materials Laboratory (58) Field surveyed (Int. Cl. ⁶ , DB name) H01L 21/68

Claims (2)

(57) [Claims] 1. A method of manufacturing an electrostatic chuck having an insulating dielectric layer and the electrode layer of tungsten, sintered
From the ceramic slurry that becomes the insulating dielectric layer
Make a lean sheet and fire on this green sheet
The paste layer containing the tungsten compound to be the electrode layer
After forming, another green sheet is placed on this paste layer
After are then laminated together, this calcination, reduction method of manufacturing an electrostatic chuck, characterized in that the. (2) The insulating dielectric layer is aluminum nitride
The method for manufacturing an electrostatic chuck according to claim 1, comprising: