JPH0469181A - Electrostatic attraction plate - Google Patents

Abstract

PURPOSE:To improve attraction force and thermal conductivity, by forming an electrostatic attraction plate with a ceramic sintered body and conductor being brazed. CONSTITUTION:A ceramic sintered body 2 of high dielectric constant of BaTiO3, SiC which are insulating materials and an electric conductor 3 of high heat conductivity of Al, Cu, W, electrically conductive SiC are subjected to brazing with the use of a brazing filler metal 5 of Su, Au, Ag, etc. A desired electrostatic attraction plate is thus obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrostatic chuck plate for electrically fixing and holding a sample when processing or inspecting the sample.

[Conventional technology]

Conventional electrostatic adsorption plates include, for example, Japanese Patent Publication No. 60-59104.
As described in the above publication, an insulating film was formed by thermally spraying a dielectric material such as M2O3 onto the electrode.

Further, for example, as described in JP-A-62-264638 and JP-A-62-94953, a conductive layer and an insulating layer made of a ceramic body mainly composed of It was formed by laminating and firing them together.

[Problem to be solved by the invention]

B@T i O3, which has a high dielectric constant, is formed by thermal spraying, in which the dielectric material is heated by plasma above its melting point and then sprayed onto the electrode.

Even if a 8i0 thermal spray material is used, thermal decomposition occurs during processing, making it impossible to form an insulating layer of BaTiO3 or SiO.

For this reason, there was a problem that a high dielectric constant could not be obtained and the adsorption force was small.

In addition, in the method of forming by firing, it is necessary to thicken the ceramic green sheet for strength reasons, and in addition, A/203
It has very poor heat conduction due to its main component. For this reason, the temperature of the sample tends to rise due to the heat generated during processing, and when applied to an electrode in an etching device, for example, there is a problem in that the quality of the resist changes.

An object of the present invention is to provide an electrostatic adsorption plate that can improve adsorption force and thermal conductivity.

[Means to solve the problem]

The technical measures taken to achieve the above purpose were to combine a ceramic sintered body with a high dielectric constant of BaTiO3, 8i0, which is an insulating material, and a conductive material with a high thermal conductivity, such as A/, Ou, W, and conductive SiO, with a high thermal conductivity of Su. The electrostatic adsorption plate is formed by brazing using a brazing material such as , Ag, or the like.

[For production]

The effects of the technical means of the present invention are as follows. The processing temperature for brazing varies depending on the melting point of the brazing material used, but is in the range of about 50°C to about 1000°C, whereas B
The temperature at which aTiO3,8i0 undergoes thermal decomposition is approximately 800
C to about 2000 C, and the sintered body can be applied as an insulating layer while maintaining a high dielectric constant, and the adsorption force can be improved.

Furthermore, A/, Ou, which is a large thermal conductor, is used as an electric conductor.

By appropriately using W and conductive SiO in consideration of the operating temperature and coefficient of linear expansion, it is possible to form an electrostatic adsorption plate that is inexpensive, has high mechanical strength, and has excellent thermal conductivity.

〔Example〕

Hereinafter, a method for forming an electrostatic adsorption plate according to an embodiment of the present invention will be explained as follows.
This will be explained with reference to Figure and IJ2 diagram.

First, the back surface of the ceramic sintered body 2 having edges on the surface and the surface of the conductor 3 are coated in an aqueous solution with a film thickness of about 10 to 20 mm, respectively.
Plated with μ-ho Ni4, then heated to about 850℃ in vacuum.
It is heated to diffuse Ni4 and bonded.

Then, a brazing material 5 whose main component is SO (film thickness approximately 20 to 4
0 μm) is inserted between the ceramic sintered body 2 and the conductor 30, and the brazing material 5 is melted and hot pressed in a vacuum of about I x 10-5 Torr to braze the ceramic sintered body 2 and the conductor 3. do. The processing temperature in this case is approximately 25
It is in the range of 0°C to 300°C.

Thereafter, slow cooling, constant temperature maintenance, and slow cooling are performed as heat treatments to remove the stress during brazing and complete the formation.

Since brazing is performed in a vacuum in this way, it is possible to prevent pinholes from remaining between the ceramic sintered body 2 and the conductor 3, and even when used in a vacuum, vacuum insulation is maintained during this period. This does not occur and the thermal conductivity does not deteriorate. Further, since the processing temperature is at most 850° C., the ceramic sintered body 2 does not undergo thermal decomposition, resulting in a change in composition and a change in dielectric constant.

Incidentally, as the CeraEwp sintered body 2, Ba having a high dielectric constant is used.
TiO3, 8i0, which has a high thermal conductivity, is suitable as the conductor 3, and TiO3, 8i0, which has a high thermal conductivity, and Ou, W, and 8i0, which have a high conductivity, are suitable, and these are used depending on the operating temperature and linear expansion coefficient.

In addition, although 8U was used as the brazing filler metal 5, other Ag, A
If u is used, the processing temperature during brazing is approximately 620~10
Although the temperature is high in the range of 00°C, the bonding strength can be further improved.

Next, we will examine the adsorption force and thermal conductivity of an electrostatic adsorption plate for a dripping device with an operating temperature of -170'C, which was formed using 8JO with a board thickness of 0.6ml and 1ml using the wooden sword method and W with a board thickness of 9.4mm. Gender 1 strength will be explained.

The dielectric constant is about 7 (IM
Hz), whereas the dielectric constant of the 8AO sintered body is 100
01000 (I) can be obtained with the same voltage and the same -
Comparing the film thickness, the adsorption force can be improved about 130 times.

In addition, the thermal conductivity is 200W 76 inches (113
5in (thermal conductivity 126
W/m-K) surface and W (thermal conductor 167W/m-
K) The temperature difference between the back surfaces is approximately 0.7°C, which is reduced to approximately 71° when compared with a conventional A/203 (thermal conductivity 17W/m-K) fired electrode of the same thickness. It is possible to suppress the rise in wafer temperature during processing.

Furthermore, regarding the strength, the linear expansion coefficient of SiO and W is
t'L Tsure 3 X 10-'IEII/IEI'C,
4X 10-'M/wr"c, and even if the electrostatic chuck plate is cooled from room temperature to -170°C, the bending stress generated in each material is approximately 18 MPu and approximately 5 MPu. This is 8i0.W It has a bending strength of about 1/1'/l OO, which is a sufficient strength of 25#.

Also, the shear stress acting on the brazing filler metal 5 is approximately 4M.
The brazing material 5 is made of Pu and has a shear strength of approximately 1/1o of 40 MPu when 8 m is used as the brazing filler metal 5, which is no problem.

In other words, the electrostatic adsorption plate in this example was subjected to low-temperature etching gt.
By using it as an electrostatic adsorption plate, the adsorption power and thermal conductivity of samples such as semiconductor device substrates are improved, and the samples can be subjected to low-temperature etching with high precision.

〔Effect of the invention〕

According to the present invention, it is possible to provide an electrostatic adsorption plate with improved adsorption force and thermal conductivity.

4,

[Brief explanation of drawings]

FIG. 1 is a plan view of an electrostatic adsorption plate according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line A in FIG. 1. 2... Ceramic sintered body, 3... Conductor, 4... Ni, 5... Brazing metal
−Representative Patent Attorney Katsuo Ogawa

Claims (1)

[Claims] 1. An electrostatic adsorption plate characterized by being formed by brazing a ceramic sintered body and a conductor. 2. The static device according to claim 1, wherein BaTiO_3 and SiO are used as the ceramic sintered body, Al, Cu, W, and conductive SiO are used as the conductor, and Sn, Ag, and Au are used as the brazing material. Electric adsorption board.