JPS6156842A - Electrostatic attractive plate - Google Patents

Abstract

PURPOSE:To enable a plate shaped workpiece to be attractively attached in a surface contact condition to a thin layer of elastic insulating material on an insulating base plate, by providing an electrostatic electrode on a plane equal to that of the insulating base plate and finishing a surface of the insulating base plate after it forms the electrode. CONSTITUTION:An insulating base plate consists of an Al2O3 plate in diameter about 300mm., and the plate 1, after its surface is finished by machining, drills a groover for an electrode by machining. Next, the plate 1, embedding an electrode material in this groove and forming an electrostatic electrode 2 and 3, applies surface finishing again by machining so that a surface of the insulating base plate 1 may be in an equal relation to a surface of the electrostatic electrode 2 and 3. Finally the insulating base plate 1 coats its surface with a thin layer 4 of elastic insulating material to a thickness about 0.2mm.. By this electrostatic attractive plate, a plate shaped workpiece 5 placed on the thin layer 4 of elastic insulating material is attractively held to said layer 4 in a surface contact condition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrostatic chuck plate used as a holder for a plate-shaped object to be processed, such as a semiconductor chip, during semiconductor manufacturing.

[Conventional technology]

Conventionally, during semiconductor manufacturing, when etching the workpiece by ion beam milling or magnetron sputtering,
An electrostatic adsorption plate is used to hold the

As shown in FIGS. 2(a), (b) and FIG. 6, this electrostatic adsorption plate includes an insulating substrate 1 made of At203, and electrodes arranged alternately in positive and negative directions on the surface of this insulating substrate 1. comb-like shape (Fig. 2(a)) or spiral shape (Fig. 2(a))
It consists of the electrostatic electrodes 2 and 3 of b)) and an elastic insulating thin layer 4 provided covering the surface of the insulating substrate 1 and the electrostatic electrodes 2 and 3. With a plate-like object 5 to be processed, such as UNINO, placed thereon, a voltage of approximately +15001 volts and -1500 volts is applied to the positive and negative electrostatic electrodes 2 and 3 to attract and hold the plate-like object 5 to be processed. It is done like this. Then, with the plate-like object 5 to be processed being attracted and held by this electrostatic adsorption plate, the plate-like object 5 to be processed is subjected to an etching process, for example, by ion beam milling. Thermal energy is generated at 5, and the temperature of the plate-shaped object 5 to be processed rises. If this temperature rise is significant, the photorenost coated on the top surface of the plate-shaped object 5 to be processed for etching will carbonize and the plate-shaped object 5 to be processed will become a defective product. The heat generated in the plate-like object 5 to be processed is transmitted to the insulating substrate 1 via the elastic insulating thin layer 4 by improving the adhesion between the upper surface and the lower surface of the plate-like object 5 to be processed.

Cooling water 6 is brought into contact with the lower surface of the insulating substrate 1, and this cooling water 6
It is designed to dissipate heat inside.

[Problem that the invention seeks to solve]

As is clear from the above description, the surface of the elastic insulating thin layer 4 needs to be as flat as possible from the viewpoint of adhesion to the plate-like object 5 to be processed.

However, in the case of conventional electrostatic adsorption plates having comb-shaped or spiral electrostatic electrodes as shown in FIGS. 2(a), (b) and 6, their electrostatic Since the electrodes 2 and 3 are deposited on the insulating substrate 1 by the silk screen printing method, the electrostatic electrodes 2 and 3 are formed as protrusions on the surface of the insulating substrate 1, so that the surface of the insulating substrate 1 and the electrostatic electrodes 2 and 3 are formed as protrusions. This has a disadvantage in that it affects the surface of the elastic insulating thin layer 40, which is provided by silk screen printing over the electrodes 2 and 3, and the surface flatness of this thin layer 4 is not good.

Therefore, if the contact state between the lower surface of the plate-like object 5 to be processed and the thin insulating material layer 4, which is preferably a surface contact state, is a point contact state, heat dissipation from the plate-like object 5 to be processed will not be sufficient. There was a case.

Generally, the heat resistant temperature of photorenost used for etching is set to be 100° C. or less, and if the temperature exceeds 100° C., the photorenost will carbonize and the plate-shaped object 5 to be processed will become unusable. When the plate-like object 5 to be processed is a silicone material with a diameter of about 75 iz, a thickness of 0.2 to Q, and about 3 mm, this silicone material has some flexibility.

Even if the flatness of the surface of the thin insulating material layer 40 is not very good, the adhesion with the plate-shaped object 5 to be processed is good, and the silicon sea urchin... The temperature rise of the processed plate-shaped body 5 is within the permissible range. On the contrary,
The plate-shaped object 5 to be processed is
In the case of glass substrates for A, A203 TIC or EB exposure masks for thin film magnetic heads, etc., the substrate of the plate-shaped object 5 to be processed does not have good thermal conductivity and has high hardness, so it does not have flexibility. Particularly good flatness of the surface of the thin layer 4 is required.

However, when the electrostatic electrodes 2 and 3 are provided protrudingly on the insulating substrate 1 by silk screen printing, it is difficult to obtain good flatness of the surface of the thin insulating layer 40.

In addition, when the electrostatic electrodes 2 and 3 are formed on the insulating substrate 1 by silk screen printing, there are also problems in accuracy and yield.

[Means for solving problems]

The present invention provides a novel electrostatic adsorption plate in which an electrostatic electrode is embedded in a surface portion of an insulating substrate in such a manner that the surface of the insulating substrate and the surface of the electrostatic electrode form the same flat plane. This is what we offer.

[For production]

According to the present invention, the flatness of the surface of the elastic insulating thin layer provided over the insulating substrate and the electrostatic electrode is extremely good,
If current is passed between the positive and negative electrostatic electrodes.

The plate-shaped object to be processed is attracted and held on the electrostatic attraction plate in surface contact with the thin layer of insulating material.

〔Example〕

FIG. 1 shows an embodiment of the electrostatic adsorption plate according to the present invention in correspondence with FIG.
A 203 plate is made, and after its surface is finished flat by machining, grooves 7 for electrodes are bored by machining. Next, electrode material is buried in this groove 7 to form electrostatic electrodes 2 and 3, and the insulating substrate 1 is machined again.
The surface of the electrostatic electrode 2 and the surface of the electrostatic electrodes 2 and 3 are flat and coplanar. Finally, a thin layer of elastic insulation material 4 is deposited over the surface of the insulating substrate 1 and the electrostatic electrodes 2 and 3 to a thickness of about Q, 2 mrn.

〔Effect of the invention〕

According to one aspect of the present invention, as is clear from the above description.

Since the electrostatic electrode is embedded in the surface of the insulating substrate in such a manner that the surface of the insulating substrate and the surface of the electrostatic electrode are flat and coplanar, the surface of the insulating substrate after electrode formation is Since the plane can be finished by machining, the surface of the thin layer of elastic insulation material deposited thereon can be provided with very good flatness. Therefore, the plate-like object to be processed is adsorbed on the electrostatic adsorption plate in a surface contact state, and there is an effect that good heat dissipation from the plate-like object to be processed is possible. Furthermore, there is the advantage that good precision and yield can be expected when forming electrostatic electrodes.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged sectional view of an electrostatic adsorption plate according to the present invention;
2(a) and 2(b) are partially cutaway plan views of a conventional electrostatic adsorption plate, and FIG. 6 is a 1 [[-
I[I] is a partially enlarged sectional view taken along line I. In the drawings, 1 is an insulating substrate, 2 and 3 are electrostatic electrodes,
4 is a thin layer of elastic insulation material, 5 is a plate-shaped object to be processed ゛°1
are shown respectively.

Claims (1)

[Claims] 1. An insulating substrate, electrostatic electrodes arranged alternately in positive and negative directions on the surface of the insulating substrate, and an elastic insulating material provided to cover the surface of the insulating substrate and the electrostatic electrodes. The electrostatic material is made of a thin layer of insulating material, and when a plate-like object to be processed is placed on this thin layer of insulating material, current is applied between the positive and negative electrostatic electrodes to attract and hold the plate-like object to be processed. The electrostatic adsorption plate is characterized in that the electrostatic electrode is embedded in a surface portion of the insulating substrate in such a manner that the surface of the insulating substrate and the surface of the electrostatic electrode form a flat coplanar relationship. Electrostatic adsorption plate.