JPS622632A - Electrostatic adsorption equipment - Google Patents

Abstract

PURPOSE:To increase thermal conductivity between the surface and the base, to assure close contact between the body to be treated and the surface, and to improve thermal conductivity between the body to be treated and the base, by making the insulation layer between the base and the adsorbing electrode of boron silicide filled rubber and making the insulation layer on the electrode of aluminum oxide filled rubber. CONSTITUTION:On the base 5, the lower insulation layer 7a made of boron nitride BN filled rubber and the upper insulation layer 8 composed of the adsorbing electrode 6 and Al2O3 filled rubber are laminated in order. When the voltage is impressed on the adsorbing electrode 6, the body W mounted on the upper insulation layer 8 is adsorbed. As to the material of 7a corresponding to the lower insulation layer 7, the BN filled rubber is used whose thermal conductivity is layer than that of the Al2O3 filled rubber by virtue of BN whose thermal conductivity is layer than that of Al2O3. Thus, the thermal conductivity of the lower insulation layer 7 is increased, which improves the capability of restraining the temperature rise.

Description

[Detailed Description of the Invention] [Summary] In an electrostatic adsorption device that is included in a vacuum processing apparatus used in a wafer process for manufacturing semiconductor devices and holds an object to be processed, an insulating layer between a substrate and a suction electrode is used. By using boron nitride-filled rubber as the material and aluminum oxide-filled rubber as the material for the insulating layer on the electrode, we can increase the thermal conductivity between the surface and the substrate and ensure the adhesion between the object to be treated and the surface. hand,
This improves the thermal conductivity between the object to be processed and the substrate.

[Industrial application field]

The present invention relates to an electrostatic adsorption device, and particularly to an electrostatic adsorption device that requires good thermal conductivity between itself and an object to be held.

A mechanical chuck is usually used as a means of holding (chucking) an object, but if this is difficult or undesirable, a vacuum chuck, electrostatic chuck (electrostatic chuck), etc. are used. .

An example of a case where an electrostatic chuck device is particularly useful is a wafer process for manufacturing semiconductor devices. For example, processes such as dry etching, ion implantation, CVD, and vapor deposition are performed using a vacuum processing apparatus in a vacuum or under extremely low pressure, so it is difficult to hold the wafer with a vacuum chuck that uses vacuum suction.

Further, there are cases where it is necessary to suppress the temperature rise of the wafer due to heat generated by the processing action, and in this case, it is desirable to bring the wafer into close contact with the holding surface, but it is difficult to achieve this purpose with a mechanical chuck.

On the other hand, an electrostatic adsorption device uses electrostatic attraction and can function even in a vacuum, and since it adsorbs almost the entire surface of the wafer, it is advantageous in bringing the wafer into close contact with the holding surface.

For this reason, vacuum suction devices are frequently used in vacuum processing equipment that needs to suppress the rise in temperature of wafers, but in order to improve the performance of the device, it is desired to further enhance the ability to suppress the temperature rise.

[Conventional technology]

FIG. 2 is a side sectional view showing the main parts of a dry etching apparatus, which is an example of a vacuum processing apparatus equipped with an electrostatic chuck device.

In FIG. 2, ■ is a vacuum processing chamber equipped with a gas inlet 1a for introducing working gas G and an exhaust port 1b for exhaust, 2 is an electrostatic adsorption device that holds a wafer W as an object to be processed, and 3 is a wafer. A discharge electrode 4 faces the electrostatic chuck device 2 with W in between, and a high frequency power source 4 causes discharge between the electrostatic chuck device 2 and the discharge electrode 3.

Dry etching is performed by holding the wafer W in an electrostatic chuck 2, creating a working gas G atmosphere with reduced pressure in the vacuum processing chamber 1, and causing a high-frequency discharge to occur between the electrostatic chuck 2 and the discharge electrode 3. conduct.

At this time, since etching is generally performed selectively on the surface of the wafer W, a patterned resist film is deposited on the surface of the wafer W. On the other hand, the ethoching action is accompanied by heat generation on the surface of the wafer W. Therefore, during etching, it is necessary to suppress the temperature rise of the wafer W to, for example, about 100° C. so that the temperature of the resist film, which has weak heat resistance, does not become excessively high, and the electrostatic chuck device is required to have this function.

FIG. 3 is a plan view (al and side sectional view (1)) showing the main part configuration of a conventional electrostatic adsorption device 2 that performs this function.

In FIG. 3, 5 is a base made of a metal with good thermal conductivity, such as aluminum, 5a is a cooling mechanism that is built into the base 5 and cools the base 5 by passing cold water, and 6 is copper, for example, about 20 μm thick. The suction electrodes 7 are made of a membrane and are arranged on a substrate 5 and form a pair of aluminum oxide (Al103) with a thickness of about 300 μm.Filled rubber, for example, silicone rubber and Al2O3 powder (by weight, silicone rubber: A)203
A lower insulating layer 8 which insulates between the base 5 and the suction electrode 6, which is made of a substantially evenly dispersed powder (approximately 1 powder - 1) (a specific example is Shin-Etsu Chemical's thermal conductive rubber TC-A). 9 is an upper insulating layer made of the same material as the lower insulating layer and has a thickness of approximately 200 μm and insulates the upper surface of the attracting electrode 6; 9 is a DC power supply that applies a DC voltage of, for example, about 3000 V to the attracting electrode 6 forming the pair.

When the wafer W is placed on the lower insulating layer 8 and the above DC voltage is applied to the attraction electrode 6, substantially the entire surface of the wafer W is attracted to the attraction electrode 6 due to electrostatic attraction, and the upper and lower insulating layers 8.
Coupled with the elasticity of the wafer 7, even if the bottom surface of the wafer W has some bends or unevenness, the entire surface is covered with the upper insulating layer 8.
closely adhere to.

Therefore, this electrostatic adsorption device 2 prevents the generation of a gap that becomes a heat transfer barrier between the wafer W and the upper insulating layer 8, and allows the base 5 to be It absorbs the heat of the wafer W and suppresses the temperature rise of the wafer W.

[Problem that the invention seeks to solve]

In the etching apparatus shown in FIG. 2, the etching speed corresponds to the discharge power applied to the discharge described above, and the higher the discharge power, the faster the etching speed, so it is desired to increase the discharge power in order to improve processing efficiency.

However, as the discharge power increases, the heat generated on the surface of the wafer W increases, so the upper limit of the discharge power depends on the ability of the electrostatic chuck device 2 to suppress the temperature rise with respect to the wafer W. Therefore, in order to further increase the discharge power, it is necessary to use an electrostatic adsorption device that has further improved temperature rise suppressing ability.

[Means for Solving the Problems] FIG. 1 is a plan view (al) and a side sectional view (b) showing the main part configuration of an embodiment of an electrostatic adsorption device according to the present invention.

The above problem arises because, as shown in FIG. 1, a lower insulating layer 7a made of boron nitride (BN)-filled rubber and an upper insulating layer 8 made of I2O3-filled rubber are sequentially attached to the suction electrode 6 on the base 5. This problem is solved by the electrostatic attraction device of the present invention, which has a laminated structure and applies a voltage to the attraction electrode 6 to attract the object W placed on the upper insulating layer 8.

[Effect]

In the conventional example shown in FIG.
7.8, Al2O3 filled rubber whose thermal conductivity was increased by filling it with Al2O3 was used to increase the thermal conductivity and obtain the above-mentioned temperature rise suppressing ability.

In this electrostatic adsorption device, 7 corresponding to the lower insulating layer 7 is used.
For the material a, BN-filled rubber, which has higher thermal conductivity than Al2O3 and has higher thermal conductivity than Al2O3-filled rubber by filling it with N, is used to increase heat transferability and achieve the above-mentioned temperature rise suppression ability than the conventional example. Improving.

Note that the reason why the material of the upper insulating layer 8 is not BN-filled rubber is that the hardness of the BN-filled rubber is higher than that of the filled rubber, which is +203.
This is because it is difficult to bring the wafer W, which is an object, into close contact.

The improvement in the temperature rise suppressing ability can be applied to, for example, an increase in the discharge power of kJ to the dry etching apparatus shown in FIG. 2, thereby improving the performance of the dry etching apparatus accordingly.

〔Example〕

An embodiment of the electrostatic chuck device according to the present invention will be described below with reference to FIG.

In the electrostatic adsorption device 2a shown in FIG. 1, the lower insulating layer 7 in the conventional example shown in FIG. 1:2 to 4) dispersed approximately evenly (a specific example is Shin-Etsu Chemical's thermal conductive rubber TC-BG)
The lower insulating layer 7a is replaced with a lower insulating layer 7a consisting of the same as the conventional example.

The thickness of the lower insulating layer 7a was changed from the conventional 7 (approximately 300 μm thick)
) The reason for making it thicker is to ensure the withstand voltage between the suction electrode 6 and the base 5 and to compensate for the increased hardness of the BN-filled rubber, so the adhesion of the wafer W remains the same as before. However, despite the increased thickness of the lower insulating layer, the thermal conductivity between the neem W and the base 5 is about 1.
It has increased five times.

When this electrostatic chuck E2a is used in the dry etching apparatus shown in FIG. The discharge power was increased by about 1.5 times, and the etching efficiency was significantly increased.

In addition, in the above conventional examples and examples, Tsuneem W
However, based on its principle, the electrostatic adsorption device of the present invention functions better than conventional ones when controlling the temperature of the object to be processed by controlling the temperature of the substrate 5. can be easily understood.

〔Effect of the invention〕

As explained above, according to the configuration of the present invention, in an electrostatic chuck device that is included in a vacuum processing apparatus used in a wafer process for manufacturing semiconductor devices and holds a to-be-processed object, It is possible to improve the thermal conductivity between the device substrate and have the effect of making it possible to improve the performance of the device using the electrostatic adsorption device, for example, by improving the processing rate of the dry notching device.

[Brief explanation of drawings]

FIG. 1 is a plan view (a) and a side sectional view (b) showing the configuration of main parts of an embodiment of an electrostatic chuck device according to the present invention, and FIG. 2 is a schematic diagram of an example of a vacuum processing device equipped with an electrostatic chuck device. Fig. 3 is a plan view showing the main part configuration of a conventional electrostatic adsorption device.
al and a side sectional view (b). In the figure, 1 is a vacuum processing chamber, 2.2a is an electrostatic adsorption device, 3 is a discharge electrode, 4 is a high frequency power source, 5 is a base, 5a is a cooling mechanism, 6 is a suction electrode, 7.7a is a lower insulating layer, 8 is an upper insulating layer, and 9 is a DC power supply. Senmengaku (2) of the embodiment of the present invention, 4 rules of tomenkoku (Tono-tei I
K

Claims (1)

[Claims] A lower insulating layer (7) made of boron nitride-filled rubber is disposed on the base (5).
a), the suction electrode (6), and the upper insulating layer (8) made of aluminum oxide filled rubber form a laminated structure, and the suction electrode (
An electrostatic adsorption device characterized in that an object (W) placed on the upper insulating layer (8) is adsorbed by applying a voltage to (6).