JP2764156B2 - 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 used for etching a film formed on the surface of a workpiece such as a semiconductor wafer or a glass substrate.

[0002]

2. Description of the Related Art A general structure of a plasma processing apparatus for performing an etching process or a CVD process on an object to be processed (hereinafter simply referred to as a wafer) such as a semiconductor wafer or a glass substrate is disclosed in Japanese Unexamined Patent Publication No. Hei.
As shown in JP-A-170684, the wafer mounting table is made to face the opening formed in the base from below and the chamber is placed around the opening, and the wafer mounting table is raised and inserted into the opening. In this state, the space between the wafer mounting table and the base is hermetically sealed, the inside of the chamber is evacuated, plasma is generated in the chamber, and the reaction gas introduced into the chamber is activated by the plasma. The coating on the wafer surface is subjected to an etching process or the like.

[0003]

By the way, a fluorocarbon gas has been conventionally used as a reaction gas in an etching process or the like, but its use tends to be restricted due to environmental problems. Chlorine-based gas has been attracting attention as a gas that can replace this CFC-based gas. However, a chlorine-based gas can exhibit optimum etching characteristics at a low temperature of about −60 ° C., and a conventional plasma processing apparatus cannot stably cool a wafer to a temperature suitable for using a chlorine-based gas.

That is, even when a coolant is supplied to the wafer mounting table to cool the wafer, the temperature of the refrigerant rises before the wafer is supplied into the wafer mounting table, or the coolant introduction pipe and the wafer mounting pipe are connected. There is a problem that the refrigerant easily leaks from the seam of the table.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is to supply a refrigerant from the outside to a refrigerant passage formed in a wafer mounting table through a refrigerant introduction pipe, and to connect the refrigerant introduction pipe to the inside. It consisted of a tube and an outer tube, a refrigerant was flowed into the inner tube, and the space between the inner tube and the outer tube was evacuated. Further, a part of the refrigerant introduction pipe was constituted by an inner metal bellows continuous with the inner pipe and an outer metal bellows continuous with the outer pipe .

[0006]

Since the space between the inner pipe and the outer pipe constituting the refrigerant introduction pipe is in a vacuum state, the heat insulation effect is high and the refrigerant temperature can be kept low.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is an overall plan view of a processing system incorporating the plasma processing apparatus according to the present invention, FIG. 2 is a longitudinal sectional view of the plasma processing apparatus, FIG. 4 is an enlarged longitudinal sectional view of a main part of the plasma processing apparatus viewed from a position different from that of FIG. 3, FIG. 5 is a sectional view taken along the line AA of FIG. 3 with a chamber mounting table removed, and FIG. FIG. 4 is a sectional view taken along the line BB of FIG. 3 in a state where a table is removed.

In the plasma processing system, a handling station 1 for loading and unloading wafers is installed at the center. The handling station 1 has a pentagonal shape in a plan view, and two side surfaces of the handling station 1 are provided with a wafer cassette storage 3 via a load lock mechanism 2, and the other two side surfaces are also provided with a load lock mechanism 4. Through the plasma processing apparatus 10 according to the present invention
Is attached.

A wafer transfer arm 5 that can rotate and expand and contract is provided inside the handling station 1, and the wafers W in the wafer cassette storage unit 3 are positioned one by one and are loaded into the plasma processing apparatus 10. At the same time, the processed wafers W are automatically returned to the wafer cassette storage unit 3.

The plasma processing apparatus 10 divides a base 11 into a base inner part 12 and a base outer part 13.
2 and the base outer part 13 are connected by four pillars 14, a wafer mounting table 15 is mounted on the base inner part 12, and a chamber mounting table 16 is mounted on the base outer part 13. A chamber 17 made of synthetic quartz is fixed on the chamber mounting table 16. Note that the chamber 17 may be directly mounted on the base outer portion 13 without providing the chamber mounting table 16.

A gap is formed over the entire circumference between the outside of the wafer mounting table 15 and the inside of the chamber mounting table 16,
This gap is defined as a downward exhaust passage 18, and a gap other than the column portion 14 between the base inner portion 12 and the base outer portion 13 is also defined as a downward exhaust passage 19. It is continuous with a funnel-shaped exhaust passage 21 formed in a lower block 20 attached to the lower surface of the base 11.

A butterfly valve 23 that is opened and closed by a rotary actuator 22 is provided in the exhaust passage 21, and a turbo-molecular pump 24 for vacuum evacuation is mounted on the lower surface of the lower block 20. The gas is drawn vertically.

Further, the cylinder unit 3 is provided in the base 11.
The arm 32 extending radially in all directions is fixed to the upper end of the rod 31 of the cylinder unit 30, and the clamper 33 of the wafer W is attached to the arm 32. The clamper 33 has a cylindrical portion 34 disposed so as to be in sliding contact with the outer peripheral surface of the wafer mounting table 15. An annular portion 35 protruding inward is integrally provided at the upper end of the cylindrical portion 34. A wafer holding portion 36 is formed on the lower surface of the inner end of the wafer W, and a plurality of hook-shaped support portions 37 for supporting the peripheral edge of the lower surface of the wafer W inward from the lower surface of the annular portion 35 are provided.
In addition, a concave portion 38 into which the support portion 37 enters when the clamper 33 is lowered is formed on the upper surface of the wafer mounting table 15.

On the other hand, an inlet pipe 40 for a coolant such as liquid nitrogen and an outlet pipe 41 for the coolant are inserted into the column portion 14, and an inlet port 42 for the coolant is formed in the wafer mounting table 15 in a spiral shape in plan view. Cooling passage 43 and refrigerant discharge port 44
Are formed. Thus, the refrigerant introduced from the introduction pipe 40 passes through the introduction port 42 and the wafer mounting table 15
While passing through the inside of the cooling passage 43, the wafer W on the wafer mounting table 15 is cooled and discharged to the outside through the discharge port 44 and the discharge pipe 41.

Here, the refrigerant introduction pipe 40 is composed of an inner pipe 45 and an outer pipe 46, in which the refrigerant flows, and a space 47 between the inner pipe 45 and the outer pipe 46 is in a vacuum state. . The middle part of the refrigerant introduction pipe 40 is connected to the inner pipe 45.
And an outer metal bellows 49 forming a part of the outer tube 46.

In the above, in order to perform the etching process on the surface of the wafer W, the coolant is introduced from the coolant introduction pipe 40 into the cooling passage 4.
3, the wafer mounting table 15 is cooled, and in this state, the rod 31 of the cylinder unit 30 is protruded to raise the clamper 33, and the annular portion 35 of the clamper 33 is raised.
The wafer W is inserted between the support portion 37 and the side, and the wafer W is placed on the support portion 37.

Next, the rod 3 of the cylinder unit 30
The wafer W is mounted on the upper surface of the wafer mounting table 15 by lowering the clamper 33 and the peripheral portion of the upper surface of the wafer W is pressed against the upper surface of the wafer mounting table 15 by the holding portion 36. At this time, the support portion 37 separates from the wafer W and enters the recess 38.

Thereafter, the pressure in the chamber 17 is reduced, a chlorine-based reaction gas is introduced into the chamber 17, microwaves (high frequency) are applied to the chamber 17 (upper electrode), and plasma is generated in the chamber 17. As a result, the reaction gas is activated, and the surface of the wafer W is etched along the pattern of the mask.

[0019]

According to the present invention as described above,
Since the refrigerant introduction pipe for supplying the refrigerant to the refrigerant passage formed in the wafer mounting table is constituted by the inner pipe and the outer pipe, the refrigerant flows in the inner pipe, and the space between the inner pipe and the outer pipe is in a vacuum state. The heat insulating effect is high, and the temperature can be kept low until the refrigerant is introduced into the wafer mounting table.

In addition, since a part of the refrigerant introduction pipe is constituted by an inner metal bellows continuous with the inner pipe and an outer metal bellows continuous with the outer pipe, not only can a dimensional error at the time of manufacture be absorbed, but also the refrigerant due to temperature change can be absorbed. The change in volume between the introduction pipe and other members can be absorbed, and the leakage of the refrigerant from the joint or the like can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is an overall plan view of a processing system incorporating a plasma processing apparatus according to the present invention.

FIG. 2 is a longitudinal sectional view of the plasma processing apparatus.

FIG. 3 is an enlarged vertical sectional view of a main part of the plasma processing apparatus.

FIG. 4 is an enlarged longitudinal sectional view of a main part of the plasma processing apparatus viewed from a position different from FIG. 3;

FIG. 5 is a sectional view taken along the line AA of FIG. 3 with the chamber mounting table removed;

FIG. 6 is a sectional view taken along the line BB of FIG. 3 with the chamber mounting table removed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Plasma processing apparatus, 11 ... Base, 15 ... Wafer mounting table, 16 ... Chamber mounting table, 17 ... Chamber, 40 ... Coolant introduction pipe, 41 ... Coolant discharge pipe, 42 ...
Refrigerant inlet port, 43 cooling passage, 44 refrigerant outlet port, 45 inner tube, 46 outer tube, 48 inner metal bellows, 49 outer metal bellows, W wafer.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuo Waki 150 Oka Nakamaruko, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Tokyo Ohka Kogyo Co., Ltd. (56) References 335276 (JP, A) Hikaru 4-94727 (JP, U)

Claims (1)

(57) [Claims] An object-to-be-processed table is viewed from below in a chamber, and a process such as etching is performed on an object to be processed on the object-to-be-processed while the inside of the chamber is depressurized and plasma is generated. In the plasma processing apparatus, the refrigerant passage is formed in the workpiece mounting table, a refrigerant is supplied to the refrigerant passage from the outside via a refrigerant introduction pipe, and the refrigerant introduction pipe is connected to the inner pipe. An outer pipe is provided, and a part of the refrigerant introduction pipe is connected to the inner pipe.
Connecting inner metal bellows and outer metal bellows
A plasma processing apparatus comprising a rose, wherein a refrigerant flows through the inner tube, and a space between the inner tube and the outer tube is in a vacuum state.