JP2675613B2 - Plasma processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a plasma processing apparatus.

(Prior Art) In a plasma processing apparatus such as a parallel plate type plasma etching apparatus, for example, RF power is applied to the upper electrode, the lower electrode supporting the wafer is grounded, and an etching gas is introduced between the both electrodes to generate plasma. Induction is performed and the wafer is being etched.

The object to be processed placed on the lower electrode is supported by the peripheral portion thereof being held between the lower electrode and the lower electrode by a ring-shaped clamper member.

(Problems to be Solved by the Invention) When etching is performed using the above apparatus,
As the etching characteristics, it is required to improve the etching rate of the layer to be etched. In order to improve the etching rate, the focus degree for confining the plasma induced between the upper electrode and the lower electrode may be increased and concentrated on the material to be etched.

However, as a result of the measurement by the present inventors, it was found that the ions generated in the plasma leaked to a site other than the material to be etched, which deteriorated the focus degree of the plasma.

Therefore, an object of the present invention is to prevent a clamper member existing in the vicinity of the object to be processed from being exposed to the plasma from being charged by the electrode on which the object to be processed is placed, and thus the plasma is prevented. It is an object of the present invention to provide a plasma processing apparatus capable of improving a processing rate, such as an etching rate or a deposition rate, by concentrating on a target object.

[Structure of the Invention] (Means for Solving the Problems) The plasma processing apparatus according to the invention of claim 1 is arranged in a plasma processing container, and a mounting electrode for mounting an object to be processed; A counter electrode disposed to face the stationary electrode and the peripheral portion of the stationary electrode to fix the object to be processed to the stationary electrode, and the surface of the metal body was covered with the first insulating layer. A clamper member, and the first of the clamper member
And a second insulating layer interposed between the opposing surfaces of the insulating layer and the storage electrode, the processing gas being introduced into the plasma processing container, and the counter electrode and the storage electrode. High-frequency power is applied between the two to generate plasma, and the plasma is concentrated on the object to be processed to perform plasma processing on the object.

A plasma processing apparatus according to a second aspect of the present invention is the plasma processing apparatus according to the first aspect, wherein the dielectric constant of the second insulating layer is smaller than the dielectric constant of the first insulating layer.

A plasma processing apparatus according to a third aspect of the present invention is the plasma processing apparatus according to the first or second aspect, wherein the second insulating layer is coated on the clamper member.

(Operation) According to the invention described in claim 1, the following operation and effect are obtained.

The clamper member existing in the peripheral portion of the object to be processed on the mounting electrode side is formed by covering the metal with the first insulating layer. In addition, a second insulating layer is formed between the first insulating layer of the clamper member and the mounting electrode. Therefore, when plasma is generated between the counter electrode and the placement electrode, the clamper member is made of the metal, even though the clamper member is made of metal. Since the layer securely insulates the mounting electrode, it is possible to reliably prevent the clamper member from being charged with a potential by the mounting electrode.

Therefore, since there is no member having an electrode potential in the peripheral portion of the object to be processed, the plasma induced in the plasma processing container is focused and concentrated on the object to be processed. The processing rate such as the deposition rate can be improved.

Further, since the clamper member can be formed of the metal and the first insulating layer coated on the metal surface, the strength is increased and the cost is increased as compared with the case where the clamper member is formed of an insulating material such as quartz or ceramic. Can also be reduced.

According to the second aspect of the present invention, by forming the dielectric constant of the second insulating layer smaller than the dielectric constant of the first insulating layer, the insulation of the clamper member with respect to the mounting electrode is strengthened, and charging is performed. Can be completely prevented, and the processing rate can be further improved.

According to the invention as set forth in claim 3, since the second insulating layer is coated on the clamper member, a member for fixing the second insulating layer to the clamper member, an adhesive agent, etc. are not required, and the manufacturing is performed. Can be simplified and the manufacturing cost can be reduced.

(Example) Hereinafter, one example in which the present invention is applied to a plasma etching apparatus will be specifically described with reference to the drawings.

In FIG. 1, this plasma etching apparatus has an upper electrode 10 and a lower electrode 30 which are arranged to face each other,
A wafer 42, which is a material to be etched, is mounted on the lower electrode 30, and between the upper electrode 10 and the lower electrode 30, RF
The power source 40 applies RF power of 380 KHz. Then, an etching gas is introduced through the upper electrode 10 and a plasma is generated between the upper electrode 10 and the lower electrode 30, so that the wafer 42 is etched.

The upper electrode 10 has a conductive cooling member 12 formed in a flange shape.
The cable from the RF power supply 40 is connected.

Further, in the cooling member 12, first and second diffusion plates 14a and 14b having a large number of holes are arranged in parallel with each other via spacers 16a and 16b. Further, a reinforcing plate 18 and an amorphous silicon electrode 20 are laminated and arranged so as to cover the opening of the cooling member 12. A shield ring 22 is provided so as to cover the periphery of the amorphous silicon electrode 20.
20 regulates the opening diameter facing the plasma.

The lower electrode 30 is capable of mounting a wafer 42, which is a material to be etched, on the upper surface of a portion protruding in a disc shape,
A ring-shaped cracker member 32 is arranged around the lower electrode 30 so as to sandwich and fix the peripheral portion of the wafer 42 with the lower electrode 30. The lower electrode
30 is grounded.

The parallel plate type etching apparatus is configured by arranging the upper electrode 10 and the lower electrode 30 as described above in parallel in the chamber with a space therebetween.

As a characteristic configuration of the present embodiment, the clamper member 32 is formed of, for example, Al 32a whose surface is treated with alumite 32b as shown in FIG. 2, and the surface of the side in contact with the lower electrode 30 is Has a low dielectric constant, and
It is coated with an insulating material having a high electric insulation property, for example, Teflon (registered trademark of DuPont) 34 which is a polymer of tetrafluoroethylene.

 Next, the operation will be described.

In the above device, by applying RF power from the RF power supply 40 between the upper electrode 10 and the lower electrode 30, and by introducing an etching gas through the upper electrode 10,
Plasma is induced between the lower electrodes 10 and 30, radicals generated in the plasma are attached to the surface of the wafer 42 to cause a chemical reaction, and ions decomposed in the plasma are
The wafer 42 which is the material to be etched is etched by colliding with the wafer 42 by being accelerated by an electric field formed between the parallel plate electrodes. By this type of parallel plate etching, anisotropic etching with reduced side etching can be performed, and etching of a fine pattern can be realized.

Here, in order to fix the wafer 42 to the lower electrode, the ring-shaped clamper member 32 that holds the periphery of the wafer 42 between the lower electrode 30 and the lower electrode 30 is coated with Teflon 34 on the surface contacting the lower electrode 30. Therefore, even if the lower electrode 30 is brought into contact with the lower electrode 30, it is not charged, and an electrically complete floating state can be maintained.

An example of the electrical insulation characteristics of the alumite 32b is as follows: volume resistivity; 8 × 10 ⁹ Ω · cm dielectric constant (1 MHz); 6 to 7, while an example of the electrical insulation characteristics of the Teflon 34 is Since the volume resistivity is 1 × 10 ¹⁸ Ω · cm or more and the dielectric constant (1 MHz) is 2.1 or less, the lower electrode 30 can be formed by coating with Teflon 34 in addition to the alumite 32b as in this example. It completely prevents the electrification between and.

Therefore, the plasma is an amorphous silicon electrode 20 whose opening diameter is regulated by the shield ring 22.
And the wafer 42 whose opening diameter facing the plasma is regulated by the electrically insulated ring-shaped clamper member 32, and the plasma can be concentrated on the wafer 42.

Therefore, in particular, the physical etching action by the ions accelerated by the electric field between the electrodes 10 and 30 is exerted on the wafer 42.
Therefore, the etching rate can be greatly improved.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

The member that insulates the clamper member 32 and the lower electrode 30 is not limited to a member coated with an insulating material, but may be a member interposed as an insulating layer. Further, various other insulating materials having a small dielectric constant and a high electrical insulation property can be used, and not only resin but cerax or the like having a particularly excellent insulation degree is preferable.

Further, the etching rate can be changed without changing other etching conditions by changing the kind of insulating material (having different electrical insulation) interposed between the clamper member 32 and the lower electrode 30. .

Further, the present invention is not necessarily applied to the plasma etching apparatus, but may be any plasma processing apparatus as long as it is applied to the plasma CVD apparatus and the deposition rate can be improved by the above action.

[Effect of the Invention] According to the invention of claim 1, the clamper member arranged in the peripheral portion of the material to be processed is reliably insulated from the mounting electrode by the first and second insulating layers. The focus degree is improved and the plasma is concentrated on the object to be processed, so that the processing rate such as the etching rate and the deposition rate of the object can be improved.

Further, since the clamper member can be formed of the metal and the first insulating layer coated on the metal surface, the strength can be increased and the cost can be reduced as compared with the case where the clamper member is formed of the insulator.

According to the invention of claim 2, the insulation of the clamper member with respect to the mounting electrode is strengthened, and the processing rate can be further improved.

According to the third aspect of the present invention, a member for fixing the second insulating layer to the clamper member, an adhesive agent, etc. are not required, so that the manufacturing can be simplified and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a plasma etching apparatus to which the present invention is applied, and FIG. 2 is a sectional view of a clamper member. 10: upper electrode, 30: lower electrode, 32: clamper member, 34: insulating material, 42: object to be processed.

Claims (3)

(57) [Claims] 1. A mounting electrode disposed in a plasma processing container for mounting an object to be processed, a counter electrode disposed to face the mounting electrode, and a peripheral portion of the mounting electrode. A clamper member in which the object to be processed is fixed to the storage electrode and the surface of the metal body is covered with a first insulating layer, and a facing surface between the first insulating layer of the clamper member and the storage electrode. A second insulating layer interposed therebetween; and introducing a processing gas into the plasma processing container, and applying high-frequency power between the counter electrode and the placement electrode to generate plasma. The plasma processing apparatus is characterized in that the plasma is concentrated on the object to be processed for plasma processing of the object. 2. The plasma processing apparatus according to claim 1, wherein the dielectric constant of the second insulating layer is smaller than the dielectric constant of the first insulating layer. 3. The plasma processing apparatus according to claim 1, wherein the second insulating layer is coated on the clamper member.