JPS6156843A - Electrostatic attractive plate - Google Patents

Abstract

PURPOSE:To enable a plate shaped workpiece to be easily removed when it is removed from an electrostatic attractive plate, by providing grooves on the surface of a thin layer of elastic insulating material in a condition such that ratio of a width of the groove to its space obtains 1:10. CONSTITUTION:An insulating base plate 1 consists of a Al2O3 plate in diameter about 300mm., and its surface applies surface finishing by machining. Next the plate 1 forms an electrostatic electrode 2, 3 by the method of silk screen printing, further the surface of the insulating base plate 1 is coated with a thin layer 4 of elastic insulating material in a thickness about 0.2mm. by using the method of silk screen printing. Thereafter, this insulating material thin layer 4 provides on its surface a groove 8 in width about 1.5mm. in such a manner that ratio of the width of the groove to its space obtains 1:10. By this electrostatic attractive plate, the groove 8, being provided in a sporadic condition, enables good diffusion of heat from a plate shaped workpiece 5 to be obtained. While the plate shaped workpiece is also easily removed from the thin layer 4 of insulating material by forcing nitrogen gas or the like to be fed by pressure into the groove 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tortoise suction plate used as a holder for a plate-like object to be processed, such as a semiconductor unit, during semiconductor manufacturing.

[Conventional technology]

Conventionally, in semiconductor manufacturing, an electrostatic chuck plate has been used to hold a wafer to be processed when the wafer to be processed is etched by ion beam milling or magnetron sputtering.

This electrostatic adsorption plate is 1, for example, as shown in FIGS. 5 and 4, At20. An insulating substrate 1 consisting of an insulating substrate 1, comb-shaped electrostatic electrodes 2 and 3 arranged alternately in positive and negative directions on the surface of the insulating substrate 1, and provided so as to cover the surface of the insulating substrate 1 and the electrostatic electrodes 2 and 3. +1500 volts is applied to the positive and negative electrostatic electrodes 2 and 3 while a plate-like object to be processed, such as a semiconductor chip, is placed on the insulating thin layer 4. A voltage of approximately -1,500 volts is applied to hold the plate-shaped object 5 to be processed by suction. 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 in the body 5 and the temperature of the plate-shaped body 5 to be processed rises. If this temperature rise is significant, the photorenost coated on the top surface of the plate-like object 5 to be processed for etching will be carbonized and the plate-like object 5 to be processed will be carbonized.
1. The thin elastic insulating material layer 4 is made to have good adhesion between the upper surface of the thin elastic insulation layer 4 and the lower surface of the plate-like object 5 to be processed.
The heat generated is transmitted to the insulating substrate 1 via the elastic insulating thin layer 4, and cooling water 6 is brought into contact with the lower surface of the insulating substrate 1, so that the heat is radiated into the cooling water 6.

[Problem that the invention seeks to solve]

As is clear from the above description, when the electrostatic electrodes 2 and 3 are energized, the plate-like object 5 to be processed becomes an electrostatic adsorption plate.

In the case where the plate-shaped body 5 to be processed and the thin insulating material layer 4 are held by suction, good adhesion between the plate-shaped body 5 to be processed and the thin insulating material layer 4 is required.

When the electrostatic electrodes 2 and 3 are de-energized and the workpiece plate 5 is removed from the electrostatic adsorption plate 1. If the adhesion between the two is good, the electrodes will remain in close contact even after the de-energization is stopped. Therefore, it was difficult to remove the plate-shaped object 5 to be processed.

One possible solution to this problem is to provide grooves 7 on the surface of the thin insulating layer 4 as shown in FIG. However, if the interval between the grooves 7 is set to 1:
If it is dense as shown in Fig. 3, the surface of the white part will be concave, as shown in the enlarged view of Fig. 6, and the plate-like object 5 to be processed and the thin insulating material layer 4 placed on it will become indented. Rather than creating a space between the two and resulting in a point contact between the two, which makes it impossible to obtain a stable support, the heat generated in the plate-shaped object 5 to be processed is sufficiently transferred to the insulating substrate 1 side. This causes the inconvenience of not being transmitted. Since the thin layer of insulating material 4 is formed on the surface of the insulating substrate 1 by the inkjet printer printing method, it has been impossible to correct such dents by post-processing.

[Means for solving problems]

Therefore, in the present invention, even if grooves are provided on the surface of the thin layer of elastic insulating material to facilitate removal of the plate-like object to be processed after processing, the grooves are designed to ensure adhesion to the plate-like object to be processed. It was set up sparsely so that it would hang down.

[For production]

The grooves provided on the surface of this thin layer of elastic insulation material.

By spacing them sparsely at a ratio of 1:10 or more, the flatness of the surface of the thin insulating layer is maintained well.
Therefore, the adhesion of the plate-shaped object to be processed is good, and when the electricity to the electrostatic electrode is stopped after processing and the plate-shaped object to be processed is removed from the electrostatic adsorption plate, for example, nitrogen gas is injected into the groove. Removal is facilitated by pumping).

[Embodiments of the invention]

FIG. 1 shows an embodiment of the electrostatic adsorption plate according to the present invention in correspondence with FIG.
After the surface of the 03 plate was flat-finished by machining, the electrostatic electrodes 2 and 3 were formed by silk screen printing.

Furthermore, a thin layer 4 of elastic insulating material with a thickness Q of about 2 mm is deposited over the surface of the insulating substrate 1 and the electrostatic electrodes 2 and 3 using a silk screen printing method.
A groove 8 having a width of about 1.5 mm is provided on the surface of the plate. The interval between the grooves 8 is preferably 1:10 or more.

FIG. 2 shows another embodiment of the present invention, in which electrostatic electrodes 2 and 3 are placed on the surface of an insulating substrate 1, and the surface of the insulating substrate l and the surfaces of the electrostatic electrodes 2 and 3 are flat and on the same plane. It is buried in such a manner that

In this way, the flatness of the surface of the thin insulating material layer 40 can be further improved.

〔Effect of the invention〕

As is clear from the above description, according to the present invention.

The surface of the thin layer of elastic insulating material is provided with a means to ensure adhesion to the plate-shaped object to be processed and to facilitate the removal of the plate-shaped object to be processed, such as sparsely formed grooves. Good heat dissipation from the body is possible, and the plate-shaped body to be processed can be easily removed by pumping an inert gas such as nitrogen gas into the groove.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged cross-sectional view of one embodiment of an electrostatic chuck plate according to the present invention, FIG. 2 is a partially enlarged cross-sectional view of another embodiment, and FIG. 5 is a part of a conventional electrostatic chuck plate. Plan view cut away, No. 4
The figure is a partially enlarged sectional view taken along line IV-IV in Figure 6.
The figure is a partially enlarged sectional view of a conventional electrostatic chuck plate, and FIG. 6 is a partially enlarged view of FIG. 5. In the drawings, 1 is an insulating substrate, 2 and 3 are electrostatic electrodes,
4 is a thin layer of elastic insulating material, and 5 is a plate-shaped object to be processed. 8 indicates a groove, 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 electrochucking plate is characterized in that means is provided on the surface of the elastic insulating thin layer to ensure adhesion to the plate-like object to be processed and to facilitate removal of the plate-like object after processing. Electrostatic adsorption plate. 2. The electrostatic adsorption plate according to claim 1, wherein said means is a groove roughly formed on said thin layer of elastic insulating material.