JPH04330722A - wafer processing equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a wafer processing apparatus that performs processes such as CVD processing and plasma etching in one of semiconductor manufacturing equipment, and in particular, a wafer processing apparatus that is capable of changing the distance between opposing parallel electrodes that generate plasma. The present invention relates to a wafer processing apparatus having a wafer temperature control function.

0002

2. Description of the Related Art When wafer processing is performed, wafer processing conditions may be changed in accordance with required product performance and specifications. One of the means for changing the processing conditions is changing the electrode spacing. Furthermore, it is necessary to change the electrode spacing during the process of loading wafers onto the electrodes and removing the wafers from the electrodes. Furthermore, in the etching process, wafer temperature control affects etching speed, etching selectivity,
This is an important factor in the dimensional accuracy of etching processing, and the temperature of the wafer is controlled to a predetermined temperature by cooling or heating via electrodes.

A conventional wafer processing apparatus is shown in FIG.

In the figure, 1 is a vacuum vessel, 2 is a lower electrode, and 3 is an upper electrode.

A lower electrode holder 4 is provided on the bottom of the vacuum container 1.
is attached airtightly, and a cooling plate 6 and further the lower electrode 2 are attached to the lower electrode holder 4 via an insulating plate 5. A cooling passage 7 is formed in the cooling plate 6.
A refrigerant inlet pipe (not shown) is connected to the starting end of the cooling path, and a refrigerant outlet pipe (not shown) is connected to the end of the cooling path, so that a refrigerant such as water flows in and out through the refrigerant inlet pipe and the refrigerant outlet pipe. There is.

[0006] An arm 8 is provided inside the lower electrode holder 4 so as to be movable up and down, and the arm 8 is fixed to the tip of an elevating rod 9 that passes through the lower electrode holder 4 in an airtight manner. A post 1 through which the insulating board 5 is inserted is provided at the end of the arm 8.
A wafer clamp 11 is fixed to the upper end of the post 10. In the figure, 12 is a bellows.

A seal flange 13 is provided on the ceiling surface of the vacuum vessel 1, and an upper electrode holder 15 is fixed to the lower end of a hollow electrode support shaft 14 that passes through the seal flange 13 in a slidable manner. An insulating holder 1 is attached to the upper electrode holder 15.
The upper electrode 3 is fixed to the upper electrode 3 via 6. Further, a guide rod 17 fixed to the upper electrode 3 is provided to pass through the electrode support shaft 14, and a reaction gas introduction mechanism is provided inside the guide rod 17.

A pair of upper and lower seals 18 and 19 are provided between the seal flange 13 and the electrode support shaft 14 with a gap in the axial direction, and a vacuum is applied between the seals 18 and 19 by a vacuum pump (not shown). It is being pulled.

Next, an electrode spacing changing device 20 is provided on the upper surface of the seal flange 13 and around the electrode support shaft 14.
is provided.

An outer cylinder 21 is arranged concentrically with the electrode support shaft 14.
A nut ring 23 is rotatably provided on the outer cylinder 21 via a bearing 22. The nut ring 2
3 is screwed onto the electrode support shaft 14 and connected to a rotational drive mechanism (not shown). Further, although not particularly shown, the electrode support shaft 14 is prevented from rotating.

[0011] The electrode spacing can be changed by changing the nut ring 23.
This is done by rotating the electrode support shaft 14 and raising and lowering the electrode support shaft 14.

Further, the loading and unloading of the wafer 24 is performed with the wafer clamp 11 raised via the lifting rod 9 and the arm 8, and when the wafer 24 is being processed, the wafer clamp 11 is lowered and the wafer 24 is lifted up. This is done with the wafer 24 in close contact with the lower electrode 2 by clamping the edges of the wafer 24 .

[0013]

[Problems to be Solved by the Invention] Currently, semiconductor devices are becoming increasingly densely packed, and processing accuracy and line width to be processed are now in the submicron era. Therefore, in manufacturing semiconductor devices with high precision and high reliability, it is essential to prevent the generation of fine dust (particles) and the contamination caused by the particles. However, in the above-mentioned wafer processing apparatus, since the upper electrode is structured to move, the sliding part is located above the vacuum chamber, and the sliding part is adjacent to the inside of the vacuum chamber. Therefore, there is an extremely high possibility that the scattered particles will fall onto the wafer and contaminate it.

Furthermore, the conventional refrigerants described above use water as the refrigerant. Therefore, it does not have a particularly insulated structure. However, in recent years, in order to obtain high etching selectivity while preventing etching in the direction parallel to the wafer surface and side etching, which are related to the dimensional accuracy of etching processing, it is necessary to cool the wafer to a temperature (low temperature) at which side etching does not occur. is required. For this reason, a heat insulating structure is essential for the refrigerant supply and discharge structure. When the supply/exhaust structure is made of a heat-insulating structure, the diameters of the inlet pipe and the outlet pipe inevitably become large. However, as is clear from the prior art example, the lifting mechanism for the wafer clamp is located at the center of the apparatus. Therefore, the space occupied by the refrigerant inlet pipe and refrigerant outlet pipe is extremely limited, and for this reason, it is currently difficult to make the refrigerant inlet pipe and refrigerant outlet pipe an insulating structure that requires space. .

In view of the above circumstances, the present invention minimizes particle contamination of the wafer due to the operation of changing the electrode spacing, and
Moreover, it is an object of the present invention to provide a wafer processing apparatus that is capable of cooling wafers using a low-temperature refrigerant.

[0016]

[Means for Solving the Problems] The present invention is arranged in a vacuum container, generates plasma between a pair of upper and lower parallel plate electrodes facing each other, and places the wafer on the lower electrode via a wafer mounting plate. In a wafer processing apparatus for processing wafers, a lower electrode support tube extending loosely through the bottom surface of the vacuum chamber is fixed to the lower electrode side, and a loose portion of the support tube extending through the vacuum processing chamber is hermetically surrounded by a bellows. , an actuator for changing the electrode spacing is provided at the lower end of the support cylinder, a push-up and down bar is provided that passes through the lower electrode and is fixed to the wafer mounting plate so as to be movable up and down; an inner cylinder is provided concentrically with the push-down bar; A refrigerant supply pipe and a refrigerant discharge pipe are provided in multiple layers, the inner cylinder and the refrigerant supply pipe form a refrigerant supply passage, the refrigerant supply pipe and the refrigerant discharge pipe form a refrigerant discharge passage, and the refrigerant supply passage is connected to the lower electrode. The refrigerant discharge path is connected to the starting end of the cooling path provided in the cooling path, and the refrigerant discharge path is connected to the terminal end of the cooling path.

[0017]

[Operation] The electrode spacing is changed by driving the actuator to move the lower electrode, and the wafer temperature is controlled by supplying coolant from the coolant supply path to the cooling path, and by circulating the coolant through the cooling path. Moreover, the refrigerant is discharged from the refrigerant discharge path. The mechanism for changing the electrode spacing and the refrigerant supply/discharge mechanism are integrated in the center, making the structure simple and occupying a small space.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In this embodiment, the upper electrode is fixedly provided on the ceiling of the vacuum vessel, and various known means can be used for fixing it, and it is not particularly shown in the drawings. Further, in FIG. 1, the same components as those shown in FIG. 3 are given the same reference numerals.

A support tube 26 is loosely inserted through the bottom of the vacuum container 1,
A flange 27 is fixed to the lower end of the support cylinder 26, an actuator 28 such as an air cylinder is attached to the flange 27, a slide bearing 29 is provided to the flange 27, and a guide rod is installed upright on the lower surface of the vacuum vessel 1. 30 and the bearing 29 is fitted therein.

A lower electrode holder 4 is attached to the upper end of the support tube 26.
A cooling plate 6 and further a lower electrode 2 are attached to the lower electrode holder 4 via an insulating plate 5. A cooling path 7 is formed in the lower electrode 2 .

A wafer clamp rod 31 is inserted into a predetermined position around the insulating board 5 in parallel with the support cylinder 26, and the wafer clamp rod 31 is urged downward by a spring 32. Further, a clamp claw 33 is fixed to the upper end of the wafer clamp rod 31. A stopper 34 disposed below the wafer clamp rod 31 and on the axial extension of the wafer clamp rod 31 is fixed to the bottom surface of the vacuum chamber 1.

A bellows 35 is airtightly attached between the lower electrode holder 4 and the vacuum vessel 1 so as to surround the vacuum vessel insertion portion of the support tube 26.

An inner cylinder 36 and a refrigerant supply pipe 37 are arranged in multiple layers on the lower surface of the lower electrode 2 concentrically with the support cylinder 26,
Fix tightly. Further, a hollow push-down rod 38 is provided inside the inner cylinder 36, and a refrigerant discharge pipe 39 is provided outside the refrigerant supply pipe 37.

A refrigerant supply passage 40 is formed by the gap formed between the inner cylinder 36 and the refrigerant supply pipe 37, and a refrigerant discharge passage 41 is formed by the gap formed between the refrigerant supply pipe 37 and the refrigerant discharge pipe 39. . The refrigerant supply path 40 communicates with an external refrigerant supply source through a supply path branch pipe 42, and the refrigerant discharge path 41 communicates with an external refrigerant supply source through a discharge path branch pipe 43. Further, the refrigerant supply path 40 and the refrigerant discharge path 41 are each communicated with the cooling path 7.

A wafer mounting plate 44 is fixed to the upper end of the push-down bar 38, and the hollow part of the push-down bar 38 is inserted into the vacuum chamber 1.
The opening is in the circular part. Further, a flange 46 at the upper end of a transmission rod 45 is fixed to the lower end of the push-up/down rod 38 . The flange 46 is provided with a communication path 47 that communicates with an external helium gas supply source (not shown), and the communication path 47 communicates with the inside of the push-up and down rod 38 .

A base plate 48 is hermetically fixed to the lower ends of the inner pipe 36, refrigerant supply pipe 37, and refrigerant discharge pipe 39, and the push-up and down rod 38 is loosely inserted into the base plate 48. A bellows 49 surrounding the lower end of the push up/down rod 38 is airtightly attached between the base plate 48 and the flange 46.

The transmission rod 45 is slidably attached via a slide bearing 51 to a bridge 50 attached to the lower surface of the flange, and is biased downward by a spring 52. Although not particularly shown, the transmission rod 45 is pushed up by a necessary means.

The operation will be explained below.

Note that FIG. 1 shows a state in which the lower electrode 2 is lowered, the wafer clamp is released, and the wafer mounting plate 44 is raised to raise the wafer 24.

When loading the wafer 24 into the apparatus, it is carried out in the state shown in FIG.

To obtain the state shown in FIG. 1, the actuator 28 is extended, and the lower electrode 2 is lowered together with the lower electrode holder 4, the insulation board 5, the cooling board 6, etc. via the flange 27 and the support cylinder 26. .

As the lower electrode 2 descends, the push-down rod 38, inner cylinder 36, refrigerant supply pipe 37, refrigerant discharge pipe 39, and transmission rod 45, which are integrated with the lower electrode 2, also descend. The wafer clamp rod 31 does not come into contact with the stopper 34 when the lower electrode 2 first descends, but comes into contact only when the lower electrode 2 descends a required distance. The maximum amount of extension of the actuator 28 is such that the wafer clamp rod 31 reaches the stopper 34.
The wafer clamp rod 31 and the clamp claw 33 are brought into contact with the spring 32 and further expanded to the state shown in FIG.
It is assumed that it can be raised relative to the lower electrode 2.

With the lower electrode 2 lowered to the lowest position, when the transmission rod 45 is pushed up by a means not shown, the wafer mounting plate 44 is raised via the push-down rod 38, and the wafer 24 is lifted up. .

In this state, the wafer is taken out and loaded by a wafer transport means (not shown).

To process the wafer 24, the push-up of the transmission rod 45 by means not shown is released, the restoring force of the spring 52 lowers the wafer mounting plate 44, and the wafer 24 is placed on the lower electrode 2. let

Next, the actuator 28 is shortened, the lower electrode holder 4 and the lower electrode 2 are raised, the clamp claws 33 are lowered relative to the lower electrode 2, and the wafer 24 is clamped by the clamp claws 33.

After the wafer 24 is clamped, the wafer 2
4, and the subsequent shortening of the actuator 28, that is, raising the lower electrode, requires changing the interval between the upper and lower electrodes,
Adjustment is activated.

[0039] Therefore, only by raising and lowering the lower electrode 2 side,
The wafer 24 can be clamped and the spacing between the upper and lower electrodes can be changed.

The temperature of the wafer 24 during wafer processing is controlled by supplying a coolant from the supply channel branch pipe 42 and flowing the coolant through the cooling channel 7 through the coolant supply channel 40 to control the temperature of the wafer 24 through the lower electrode 2. The refrigerant is further cooled through the refrigerant discharge path 41
The water is then discharged from the discharge path branch pipe 43.

In addition, in controlling the temperature of the wafer 24, in order to improve the heat transfer efficiency between the lower electrode 2 and the wafer 24, helium gas is supplied from the connecting path, and the helium gas is connected to the wafer 24 through the push-down rod 38. The gap between the lower electrodes 2 is filled with helium gas.

Next, the wafer is cooled using a low-temperature refrigerant below freezing. In order to be able to use such a low-temperature refrigerant, the pipes forming the refrigerant flow path, such as the refrigerant supply pipe 37 and the refrigerant discharge pipe 39, have a heat-insulated double pipe structure.

The vacuum insulation structure of the refrigerant discharge pipe 39 is a double pipe structure consisting of an outer wall pipe 39a and an inner wall pipe 39b.
There is a vacuum between a and the inner wall tube 39b.

A joint seat 53 is provided in the middle of the outer wall pipe 39a, and an outer wall pipe 43a of a discharge branch pipe 43 extending in a direction perpendicular to the axis of the refrigerant discharge pipe 39 is fixed to the joint seat 53.
The inner wall pipe 43b of the discharge branch pipe 43 communicates with the inner wall pipe 39b of the refrigerant discharge pipe 39. The outer wall pipe 43a and the inner wall pipe 43b of the discharge branch pipe 43 are hermetically closed at their tips, and the gap between the outer wall pipe 43a and the inner wall pipe 43b is the gap between the outer wall pipe 39a and the inner wall pipe 39b of the refrigerant discharge pipe 39. It communicates with the void and is a vacuum.

A connecting pipe 54 made of an insulating material is fitted into the discharge branch pipe 43 and is airtightly attached to the joint seat 53, and the outflow pipe 56 is fitted into the connecting pipe 54. 5
4 and the outflow pipe 56 are airtightly connected.

The outflow pipe 56 is also similar to the refrigerant discharge pipe 39.
It is an insulated pipe with a heavy pipe structure.

The refrigerant supply pipe 37 provided inside the refrigerant discharge pipe 39 has a double pipe insulation structure like the refrigerant discharge pipe 39, and the lower electrode 2 is connected to the upper end of the refrigerant supply pipe 37.
The insulating flange 57 fixed to the
A mold joint 58 is fixed.

A plug 5 is provided at the lower end of the refrigerant discharge pipe 39.
9 is fitted and airtightly attached, and the refrigerant supply pipe 37 passes through the plug 59.

Upper flange 60 of the T-shaped joint 58
is fixed to the outer wall tube 37a of the refrigerant supply pipe 37, and the upper flange 60 is hermetically fixed to the plug 59. Further, an outer wall tube 58a of the T-shaped joint 58 is fixed to the upper flange 60, and a portion of the outer wall tube 58a is located in the middle of the outer wall tube 58a.
A T-shaped seat 61 is provided.

An inner wall tube 58b of the T-shaped joint 58 is fixed to the lower end of the inner wall tube 37b of the refrigerant supply pipe 37 extending into the T-shaped joint 58. The lower flange 62 of the T-shaped joint 58 includes the inner wall tube 58a,
The outer wall tube 58b is fixed, and a plug 63 fitted into the lower end of the T-shaped joint 58 is airtightly attached to the lower flange 62.

An outer wall pipe 42a of a supply branch pipe 42 extending in a direction perpendicular to the axis of the refrigerant supply pipe 37 is fixed to the T-shaped seat 61, and an inner wall pipe 42b of the supply branch pipe 42 is fixed to the T-shaped seat 61. It communicates with the bottom end. The supply branch pipe 42 also has a double-pipe insulation structure with an outer wall pipe 42a and an inner wall pipe 42b.

A connecting pipe 55 made of an insulating material is fitted into the supply branch pipe 42 and is airtightly attached to the T-shaped seat 61.
An inflow pipe 64 is fitted into the connecting pipe 55, and the connecting pipe 55 and the inflow pipe 64 are airtightly connected.

[0053] The inflow pipe 64 is also a double-pipe heat-insulated pipe.

Inner pipe 6 provided inside refrigerant supply pipe 37
The upper end of 5 is fixed to the lower electrode 2, and the lower end is fixed to the plug 6.
3 and protrudes into the bellows 49. The push up and down rod 38 is inserted through the inner tube 65, and the upper end of the push up and down rod 38 is slidably supported by a guide 66.

In the above-described configuration, the cylindrical gap formed between the inner pipe 65 and the refrigerant supply pipe 37 becomes the refrigerant supply path 40, and the refrigerant supply path 40 communicates with the cooling path 7. ing. Further, a cylindrical gap formed between the refrigerant supply pipe 37 and the refrigerant discharge pipe 39 serves as a refrigerant discharge passage 41, and the refrigerant discharge passage 41 communicates with the cooling passage 7.

The refrigerant supplied from the inflow pipe 64 passes through the refrigerant supply path 40 to reach the cooling path 7, cools the lower electrode 2 while flowing through the cooling path 7, and flows into the refrigerant discharge path 41. do. The refrigerant that has passed through the refrigerant discharge path 41 is discharged to the outside of the apparatus through the outflow pipe 56.

In this embodiment, the multi-tube structure is concentrated in the center, resulting in a simple structure, and furthermore, the low-temperature refrigerant flows through the center, and the high-temperature refrigerant is mixed with the low-temperature refrigerant. Since the refrigerant flows outside the refrigerant and all the tubes through which the refrigerant flows have a double-pipe structure with a vacuum insulation layer, the insulation effect is extremely high.

In the above embodiment, the helium gas is supplied from the inside of the push-down rod using a hollow tube. You can also do this. In this case, the supplied helium gas is cooled by the coolant, making the wafer cooling more effective.

[0059]

[Effects of the Invention] As described above, the present invention has a structure in which the lower electrode is movable, and by placing the sliding part completely outside the processing chamber, contamination of the wafer by particles can be minimized. Furthermore, since the large electrode movable mechanism, wafer lifting mechanism, and coolant supply/discharge mechanism are all concentrated in the center, it occupies less space and allows the use of double-insulated tubes with a vacuum layer. It exhibits various excellent effects, such as realizing cooling with low-temperature refrigerant.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view showing one embodiment of the present invention.

[Fig. 2] Fig. 1 showing details of the refrigerant supply/discharge section in this embodiment.
This is a view corresponding to arrow A of FIG.

FIG. 3 is a sectional view showing a conventional example.

[Explanation of symbols]

1 Vacuum container 2 Lower electrode 3 Upper electrode 7 Cooling path 26 Support tube 28 Actuator 35 Bellows 36 Inner cylinder 37 Refrigerant supply pipe 38 Push up and down bar 39 Refrigerant discharge pipe 40 Refrigerant supply path 41 Refrigerant discharge path 44 Wafer mounting plate

Claims (1)

[Claims] 1. A wafer processing apparatus that is disposed in a vacuum container, generates plasma between a pair of upper and lower parallel plate electrodes facing each other, and processes a wafer placed on a lower electrode via a wafer mounting plate. A lower electrode support tube that loosely extends through the bottom surface of the vacuum container is fixed to the lower electrode side, a loose portion of the support tube through the vacuum processing chamber is hermetically surrounded by a bellows, and an electrode gap is formed at the lower end of the support tube. An actuator for changing is provided, a push-up and down bar that penetrates the lower electrode and is fixed to the wafer mounting plate is provided so as to be movable up and down, and an inner cylinder, a coolant supply pipe, and a coolant discharge pipe are arranged concentrically with the push-down bar. The inner cylinder and the refrigerant supply pipe form a refrigerant supply path, the refrigerant supply pipe and the refrigerant discharge pipe form a refrigerant discharge path, and the refrigerant supply path is provided at the starting end of the cooling path provided in the lower electrode. A wafer processing apparatus characterized in that a coolant discharge path is connected to an end of the cooling path.