JP3367439B2 - Plasma processing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus for performing plasma processing by introducing a microwave into etching or thin film formation of a semiconductor substrate or the like.

[0002]

2. Description of the Related Art Conventionally, as a plasma processing apparatus, FIG.
Those shown in are known. This plasma processing device is
A reaction container 103 accommodating a wafer mounting table 102 on which a wafer 101 to be processed is mounted, and an upper dielectric plate member 104 arranged above and below the reaction container 103 with a predetermined space therebetween. A lower dielectric plate member 105,
It has a microwave supply device 106 for introducing microwaves into the upper dielectric plate member 104, and a counter electrode 107 arranged in the upper part inside the reaction vessel 103. The upper dielectric plate member 104 is composed of a Teflon plate. The lower dielectric plate member 105 is made of a quartz plate.

A reaction gas supply pipe 108 for supplying a reaction gas is arranged in the reaction vessel 103. Further, an exhaust pipe 109 for discharging the gas inside is arranged in the reaction container 103. Further, the reaction vessel 103 is provided with a heater 110 which holds the reaction vessel 103 at a predetermined temperature.
A high frequency power supply 111 that supplies high frequency power to the wafer holding unit of the wafer mounting table 102 is connected to the wafer holding unit.

When the microwave from the microwave supply device 106 is introduced into the upper dielectric plate member 104, a standing wave is formed on the upper dielectric plate member 104, and the reaction vessel 103 passes through the lower dielectric plate member 105. It penetrates into the inside and plasma is generated. At this time, since the lower dielectric plate member 105 has a constant thickness, the dielectric constant of the lower dielectric plate member 105 is constant, and the plasma density distribution immediately below the lower dielectric plate member 105 is as shown in FIG. Be uniform.

[0005]

However, in the conventional plasma processing apparatus, the plasma density distribution in the vicinity of the wafer is very high as shown in FIG. 6 due to the disappearance of ions and electrons on the side wall of the reaction vessel 103. It becomes uneven. This also makes the etching very non-uniform. For example, C
4 F8 / CO / O2 / Ar = 10/24/7 / 450s
When the wafer 101 is etched under the conditions of ccm, Pressure = 60 mTorr, microwave power = 1000 W, bias power = 1400 W, the etching uniformity of the oxide film within the surface of the wafer 101 is ± 9.8.
%Met. That is, in the conventional plasma processing apparatus, there is a problem that the uniformity of plasma is poor and the etching shape is different in the plane of the wafer.

An object of the present invention is to provide a plasma processing apparatus which can improve etching uniformity.

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 is to provide a reaction container which accommodates a wafer mounting table for mounting a wafer to be processed, and the reaction container. An upper dielectric plate member and a lower dielectric plate member, which are arranged above and below the upper dielectric plate member at predetermined intervals, a microwave supply device for introducing a microwave into the upper dielectric plate member, and a reaction container A plasma processing apparatus having a counter electrode arranged on an upper part of the inside is characterized in that it has a dielectric constant adjusting dielectric member fixed to a lower surface of a central part of a lower dielectric plate member.

A second aspect of the invention is characterized in that, in the first aspect of the invention, the dielectric constant adjusting dielectric member is made of alumina.

According to a third aspect of the invention, in the first aspect of the invention, the dielectric constant adjusting dielectric member is made of ceramics.

According to a fourth aspect of the present invention, there is provided a reaction container accommodating a wafer mounting table for mounting a wafer to be processed, and the reaction container is disposed above and below the reaction container at a predetermined interval. Plasma treatment having an upper dielectric plate member, a lower dielectric plate member, a microwave supply device for introducing microwaves into the upper dielectric plate member, and a counter electrode arranged in an upper portion inside a reaction vessel The apparatus is characterized by having a plurality of dielectric constant adjusting dielectric members fixed to a lower surface or an upper surface of a central portion of the lower dielectric plate member.

A fifth aspect of the invention is characterized in that, in the fourth aspect of the invention, the dielectric constant adjusting dielectric member is made of alumina.

According to a sixth aspect of the invention, in the fourth aspect of the invention, the dielectric constant adjusting dielectric member is made of ceramics.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the plasma processing apparatus of the present invention has a reaction container 3 containing a wafer mounting table 2 for mounting a wafer 1 to be processed, and an upper portion of the reaction container 3. An upper dielectric plate member 4 and a lower dielectric plate member 5 which are vertically arranged at a predetermined interval, and a microwave supply device 6 for introducing a microwave into the upper dielectric plate member 4.
And the counter electrode 7 arranged in the upper part of the inside of the reaction vessel 3.
And have. The upper dielectric plate member 4 is composed of a Teflon plate. The lower dielectric plate member 5 is made of a quartz plate.

A reaction gas supply pipe 8 for supplying a reaction gas is arranged in the reaction container 3. Further, an exhaust pipe 9 for discharging the gas inside is arranged in the reaction container 3.
Further, the reaction container 3 is provided with a heater 10 which holds the reaction container 3 at a predetermined temperature. The wafer holder of the wafer mounting table 2 has a high-frequency power supply 1 for applying high-frequency power to the wafer holding part.
1 is connected. On the lower surface of the central portion of the lower dielectric plate member 5, a dielectric constant adjusting dielectric member 12 processed into a screw shape is fixed by being screwed into the lower dielectric plate member. The dielectric constant adjusting dielectric member 12 is made of alumina.

Next, the operation of the plasma processing apparatus of the present invention will be described. The gas in the reaction container 3 is exhausted from the exhaust pipe 9 to set the inside of the reaction container 3 to a predetermined pressure, and then the reaction gas is supplied into the reaction container 3 from the reaction gas supply pipe 8. Next, when the microwave from the microwave supply device 6 is introduced into the upper dielectric plate member 4, the upper dielectric plate member 4
A standing wave is formed on the upper part, penetrates into the inside of the reaction container 3 through the lower dielectric plate member 5, and plasma is generated.

In the plasma processing apparatus of the present invention, the dielectric member 12 for adjusting the dielectric constant is provided on the lower surface of the central portion of the lower dielectric plate member 5.
By fixing the lower dielectric plate member 5, the dielectric constant of the central portion of the lower dielectric plate member 5 is changed, and as shown in FIG.
The plasma density immediately below the wafer is artificially made non-uniform, and the disappearance of ions and electrons on the side wall of the reaction vessel 3 is used to make the wafer 1
The plasma density distribution in the vicinity of is uniform.

FIG. 3 shows the result of measuring the plasma density in the vicinity of the wafer 1 in the plasma processing apparatus of the present invention. As shown in FIG. 3, the plasma density distribution near the wafer 1 is very good. Furthermore, the wafer 1 was etched by the plasma processing apparatus of the present invention under the above-described etching conditions, and the etching uniformity of the oxide film on the wafer 1 was measured and found to be ± 2.8%.

In the above embodiment, the dielectric constant adjusting dielectric member 12 may be made of ceramics such as SiC. The dielectric constant adjusting dielectric member 12 may be adhered to the lower dielectric plate member 5 with an inorganic adhesive or a heat resistant organic adhesive. The dielectric constant adjusting dielectric member 12 may be fixed to the upper surface of the central portion of the lower dielectric plate member 5. Further, a plurality of dielectric constant adjusting dielectric members 12 may be fixed to the lower surface and the upper surface of the lower dielectric plate member 5.

[0020]

The plasma processing apparatus of the present invention can improve etching uniformity.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a plasma processing apparatus as one embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the plasma processing apparatus of FIG.

FIG. 3 is another diagram for explaining the operation of the plasma processing apparatus of FIG.

FIG. 4 is a schematic diagram showing a conventional plasma processing apparatus.

5 is a diagram for explaining the operation of the plasma processing apparatus of FIG.

FIG. 6 is another diagram for explaining the operation of the plasma processing apparatus of FIG.

[Explanation of symbols]

1 wafer 2 Wafer mounting table 3 reaction vessels 4 Upper dielectric plate member 5 Lower dielectric plate member 6 microwave supply device 7 Counter electrode 8 Reaction gas supply pipe 9 exhaust pipe 10 heater 11 High frequency power supply 12 Dielectric material for dielectric constant adjustment

Claims (6)

(57) [Claims] 1. A reaction container accommodating a wafer mounting table on which a wafer to be processed is mounted, and an upper dielectric plate member arranged above and below the reaction container at a predetermined interval. A plasma processing apparatus comprising: a lower dielectric plate member; a microwave supply device for introducing microwaves into the upper dielectric plate member; and a counter electrode arranged in an upper part inside the reaction vessel, wherein the lower part A plasma processing apparatus comprising a dielectric constant adjusting dielectric member fixed to a lower surface of a central portion of the dielectric plate member. 2. The plasma processing apparatus according to claim 1, wherein the dielectric constant adjusting dielectric member is made of alumina. 3. The plasma processing apparatus according to claim 1, wherein the dielectric constant adjusting dielectric member is made of ceramics. 4. A reaction container accommodating a wafer mounting table for mounting a wafer to be processed, and an upper dielectric plate member arranged above and below the reaction container at a predetermined interval. A plasma processing apparatus comprising: a lower dielectric plate member; a microwave supply device for introducing microwaves into the upper dielectric plate member; and a counter electrode arranged in an upper part inside the reaction vessel, wherein the lower part A plasma processing apparatus comprising: a plurality of dielectric constant adjusting dielectric members fixed to a lower surface or an upper surface of a central portion of the dielectric plate member. 5. The plasma processing apparatus according to claim 4 , wherein the dielectric constant adjusting dielectric member is made of alumina. 6. The plasma processing apparatus according to claim 4 , wherein the dielectric constant adjusting dielectric member is made of ceramics.