JP3090562B2 - 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, and more particularly to a structure for obtaining electrical continuity between a lower electrode support of the apparatus and a conductive wall of a processing chamber.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, a plasma processing apparatus can raise and lower a lower electrode provided in a processing chamber by a bellows, and raise and lower the lower electrode by an appropriate driving means. Thereby, the relative distance between the upper electrode and the lower electrode can be adjusted.

The lower electrode and the lower electrode support are electrically insulated from each other. To prevent external noise and abnormal discharge, the potential difference between the lower electrode support and the conductive wall of the processing chamber is reduced. Must be held equally and grounded. But,
Since the relative position between the lower electrode support and the conductive wall of the processing chamber changes as the lower electrode support moves up and down, it is difficult to secure a reliable electrical conduction path between the two. there were.

For this reason, in a conventional apparatus, as shown in FIGS. 6 and 7, a bottom wall of a processing chamber and a lower electrode support are connected by a linear conductive member, for example, a copper wire 100 or the like. Even when the lower electrode support moves up and down, and the relative positional relationship between the bottom wall of the processing chamber and the lower electrode support changes, an electrical connection between them is maintained.

[0005] However, in order to obtain a good electrical conduction state, it is necessary to wire a large number of linear members between the lower electrode support and the bottom wall of the processing chamber. It became complicated and had many problems during maintenance. Furthermore, since a relatively long linear member is used, the electrical conduction path connecting the lower electrode support and the bottom wall of the processing chamber is relatively long, which is insufficient to completely suppress the occurrence of external noise and abnormal discharge. Configuration.

Further, as the positional relationship between the lower electrode support and the conductive wall of the processing chamber changes, the stray capacitance and inductance of the wiring for conducting between the electrode support and the processing chamber change. Since the impedance due to the inductance cannot be ignored as the RF supply frequency to the lower electrode increases, it is difficult to obtain the reproducibility of the plasma processing.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art,
The purpose is to secure an electrical conduction relationship between the lower electrode support and the conductive wall of the processing chamber by a relatively short path regardless of the positional relationship between the lower electrode support and the conductive wall, and to provide an RF supply circuit to the lower electrode. An object of the present invention is to provide a new and improved plasma processing apparatus which can be formed reliably, has a shielding effect, and can prevent external noise and abnormal discharge from occurring.

According to the present invention, there is provided, in accordance with the present invention, a processing chamber comprising a grounded conductive wall, and a high-frequency processing chamber installed in the processing chamber and electrically insulated from the conductive wall of the processing chamber. In a plasma processing apparatus comprising: a lower electrode connected to a power supply; and a lower electrode support that is electrically insulated from the lower electrode and raises and lowers the lower electrode. The wall and
An elastic member that exerts an elastic force so as to press the lower electrode support in a direction substantially perpendicular to the vertical direction of the lower electrode support is electrically connected to the lower electrode support.
And the elastic member is penetrated by the lower electrode support.
Around the elevating hole formed in the conductive wall
The base to be fixed and the lower electrode support base from the base
And the lower electrode support during assembly.
Composed of a comb-shaped part that contacts the elevating part of the platform in an annular shape
A plasma processing apparatus is provided.

[0009]

According to the present invention, the lower electrode support base and the conductive wall of the processing chamber are directly electrically connected to each other by the elastic member without using the linear conductive member as in the prior art. An electrical circuit that connects the lower electrode support and the conductive wall of the processing chamber has a short RF circuit, regardless of the relative positional relationship between the lower electrode support and the conductive wall of the processing chamber.
Since it can be formed reliably, external noise and abnormal discharge can be effectively prevented. In addition,
The elastic member is provided so that the lower electrode support is penetrated.
Base fixed around raised holes formed in conductive walls
From the base in a comb-like shape in the direction of the lower electrode support base.
At the time of assembling and lowering the lower electrode support base
If it is configured to consist of a comb tooth part that contacts in an annular shape,
A structure having a plurality of conduction paths can be easily formed. Also
If the elastic member is made of copper, sufficient elasticity and conduction
The elastic member having the property can be configured. In addition, the elastic part
A material for urging the elastic member against the lower electrode support base.
If the screw member is provided, more reliable contact can be ensured.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a plasma processing apparatus constructed according to the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, a plasma processing apparatus 1 configured according to the present invention includes a processing chamber 5 that is hermetically configured by, for example, a top wall 2, a side wall 3, and a bottom wall 4 made of aluminum. An upper electrode 6 is provided above the processing chamber 5.
Is installed. A processing gas supply path 7 is provided in the upper electrode 6, and a processing gas supplied from a processing gas source (not shown) via a mass flow controller (not shown) is supplied to a plurality of holes formed on the lower surface of the upper electrode 6. Hole 7
Through the processing chamber 5.

A lower electrode 8 is provided below the processing chamber 5. An object to be processed W, for example, a semiconductor wafer, can be mounted and fixed on the upper surface of the lower electrode 8 by an appropriate fixing means, for example, an electrostatic chuck. A focus ring 9 is provided so as to surround the surface of the lower electrode 8 on which the object to be processed is placed. Is supported by a lower electrode support 12 made of aluminum. An exhaust pipe 13 is provided below the processing chamber 5 and communicates with a vacuum pump (not shown) to evacuate the processing chamber 5.

A stretchable bellows 14 made of, for example, stainless steel is disposed between the lower surface of the lower electrode support portion 12 and the upper surface of the bottom wall of the processing chamber 5, and the lower electrode support base 11 moves up and down. Even in this case, the inside of the processing chamber 5 is kept airtight. A cylindrical elevating section 14 of the lower electrode support 11 is attached to the center of the lower electrode support 12, and a high frequency power supply 16 is provided inside the lower electrode support 11 so as to be electrically insulated from the lower electrode support 11. Are located.

A flange 17 is provided around the lower part of the elevating unit 14. Screw holes are formed in the flange 17 at appropriate intervals, and a screw shaft 20 erected on the upper surface of the base 19 of the support 18 of the processing chamber 5 penetrates the screw holes. In order to raise and lower the lower electrode 8,
The screw shaft 20 is configured to be driven to rotate by a driving device (not shown).

In the plasma processing apparatus configured as described above, in order to determine the RF supply circuit, a wall of the processing chamber 5 made of a conductive material such as aluminum, for example, a bottom wall in the illustrated example is used. It is necessary to secure an electrical conduction path between the lower electrode support 4 and the lower electrode support 11 and, in the example shown, the elevating portion 15 thereof.

Therefore, in the conventional apparatus, as shown in FIGS. 6 and 7, the bottom wall of the processing chamber and the lower electrode support are connected by a linear conductive member, for example, a copper wire 100 or the like. Even when the lower electrode support moves up and down, and the relative positional relationship between the bottom wall of the processing chamber and the lower electrode support changes, an electrical connection between them is maintained.

However, in the above configuration, in order to obtain a good electrical conduction state, a large number of linear members are wired between the lower electrode support base 11 and the bottom wall 4 of the processing chamber 5. As a result, the manufacturing and assembling of the apparatus become complicated, and there are many problems during maintenance. Furthermore, since a relatively long linear member is used, an electrical conduction path connecting the lower electrode support base 11 and the bottom wall 4 of the processing chamber 5 becomes relatively long, and the occurrence of external noise and abnormal discharge is completely prevented. Could not be suppressed.

Therefore, according to the present invention, an elastic force acts so as to press the lower electrode support 11 in the vertical direction of the lower electrode support 11, that is, in the direction perpendicular to the vertical direction, that is, in the horizontal direction. By electrically connecting the bottom wall 4 of the processing chamber 5 and the elevating part 15 of the lower electrode support 11 with the elastic member 30 as described above, the lower electrode support 11 is moved up and down to move relative to each other. Since the elastic member 30 is always in pressure contact with the elevating portion 15 even when the positional relationship changes,
It is possible to always ensure a reliable conduction state.

Next, the structure of the elastic member 30 for electrical conduction constructed according to the present invention will be described with reference to FIG. As shown in FIG.
A conductive and elastic member, for example, a member obtained by bending a copper plate so as to have a substantially J-shape in a vertical cross section can be used. The shaft portion 31 of the substantially J-shaped member 30
Is attached to the bottom surface of the bottom wall 4 of the processing chamber 5 by a suitable fixing means, for example, a screw means 32, so that the curved portion 33 of the substantially J-shaped member 30 has a desired elastic force, that is, the lower electrode support 11. Can be provided with an elastic force for pressing horizontally. As a result, even when the elevating part 15 of the lower electrode member 11 moves up and down, the curved part 33 of the substantially J-shaped member 30 is always pressed against the surface of the elevating part 15. An electric conduction path is always secured between the two members.

FIG. 3 shows another embodiment of the elastic member shown in FIG. Also in this embodiment, the basic function of each member is the same as that of the elastic member shown in FIG. 2, and therefore, the members having the same functions are given the same numbers, and the description will not be repeated. . However, in the embodiment of FIG. 3, a projection 34 extending downward in the vertical direction is provided on the bottom surface of the bottom wall 4, and a spring member 35 is attached to a surface of the projection 34 facing the lower electrode support 11. Further, a rotatable pressing member 36 is attached to the tip of the spring member 35. By further pressing the curved portion 33 of the substantially J-shaped member 30 against the lower electrode support 11 by the pressing member 36, the bottom wall 4 and the lower electrode support 1
It is possible to obtain a more stable electrical contact with the device 1.

As shown in FIG. 4, the elastic member 30 having the above-described structure is configured such that the bottom wall 4 of the processing chamber 5 and the lower electrode support 1 which are concentrically arranged in a horizontal section are arranged.
It is preferable to install a plurality of units at equal intervals between the above-mentioned one elevating unit 15. By adopting such a configuration, even when the relative positional relationship between the bottom wall 4 and the elevating unit 15 changes, a more stable electrical conduction state is always ensured between both members. This makes it possible to more reliably form an RF supply circuit for plasma processing.

As shown in FIG. 4, in order to arrange the plurality of elastic members 30 in a ring shape, for example, a comb-shaped copper plate member 40 as shown in FIG. 5 can be used. That is, at the time of manufacturing and assembling, first, both ends of the base 41 of the member 40 are connected to form a crown-shaped annular member, and then the base 41 is bent outward and the tip of the comb tooth 42 is bent in the same direction. By doing so, it is possible to make the comb tooth portion 42 function as a curved portion of the substantially J-shaped member 30 and the base portion 41 functions as a shaft portion of the substantially J-shaped member 30.
Finally, the base portion 41 is fixed to the bottom surface of the bottom wall 4, and the cylindrical elevating portion 1 having an outer diameter larger than the inner diameter of the ring is formed in the ring formed by the plurality of comb teeth portions 42.
5 can be inserted. As a result, the comb teeth 42 elastically come into contact with the elevating unit 15,
Regardless of the vertical movement of the elevating unit 15, it is possible to always maintain the electrical conduction state.

In the above, an example in which the plasma apparatus according to the present invention is applied to a plasma etching apparatus has been described.
The plasma apparatus according to the present invention is not limited to the above example, and can be applied to an ashing apparatus, a sputtering apparatus, an ion implantation apparatus, a plasma CVD apparatus, and the like.

[0023]

As described above, according to the plasma processing apparatus constructed in accordance with the present invention, the lower electrode support and the conductive wall of the processing chamber are directly electrically connected by the elastic member. Regardless of the relative positional relationship between the lower electrode support and the conductive wall of the processing chamber, an RF circuit having a short electrical conduction path can be reliably formed, so that external noise and abnormal discharge can be prevented. It has an excellent effect that it can be prevented before it happens.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a plasma processing apparatus configured based on the present invention.

FIG. 2 is an enlarged view of a contact finger portion of the plasma processing apparatus shown in FIG.

FIG. 3 is an enlarged view of another embodiment of the contact finger of the plasma processing apparatus configured according to the present invention.

FIG. 4 is a horizontal cross-sectional view of an electrical conduction path between a lower electrode support and a conductive wall of a processing chamber of a plasma processing apparatus configured according to the present invention.

FIG. 5 is an exploded view of a contact finger assembly member of the plasma processing apparatus configured according to the present invention.

FIG. 6 is a schematic diagram of a conventional plasma processing apparatus.

7 is an enlarged view of an electrical conduction path portion between a lower electrode support of the plasma processing apparatus shown in FIG. 6 and a conductive wall of a processing chamber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plasma processing apparatus 5 Processing chamber 8 Lower electrode 10 Insulating member 11 Lower electrode support base 12 Lower electrode support part 14 Bellows 15 Elevating part 30 Contact finger

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-44924 (JP, A) JP-A-61-110432 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/3065 H01L 21/203 H01L 21/205

Claims (3)

(57) [Claims] A processing chamber comprising a grounded conductive wall;
A lower electrode installed in the processing chamber and electrically insulated from a conductive wall of the processing chamber and connected to a high-frequency power supply; and a lower electrode support electrically insulated from the lower electrode and raising and lowering the lower electrode. In a plasma processing apparatus including a base, the lower electrode support and the conductive wall of the processing chamber are pressed against the lower electrode support in a direction substantially perpendicular to the elevating direction of the lower electrode support. Is configured to be electrically conductive by an elastic member on which elastic force acts
And further, the elastic member penetrates the lower electrode support.
Fixed around the lift hole formed in the conductive wall
And a comb from the base in the direction of the lower electrode support base.
It protrudes in a tooth shape, and the lower electrode support
Composed of a comb-shaped part that contacts the elevating part in an annular shape
A plasma processing apparatus. 2. The elastic member is made of copper.
The plasma processing apparatus according to claim 1, wherein 3. The elastic member according to claim 1, wherein the elastic member includes
A spring member for biasing the electrode support.
3. The plasma processing apparatus according to claim 1, wherein
Place.