JP2003017476A - Cooling apparatus for semiconductor-manufacturing apparatus, and plasma etching apparatus having the cooling apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling apparatus for a semiconductor-manufacturing apparatus that uses a thermoelectric module, and at the same time, generates less magnetic field. SOLUTION: The cooling apparatus for a semiconductor manufacturing apparatus cools a semiconductor-manufacturing apparatus (1) for machining a wafer (6) under plasma gas or electric field atmosphere or the like by a thermoelectric module (9), where thermoelectric elements (10 and 11) are provided alternately. The thermoelectric module (9) is composed of a first path (12a), where current flows in an arbitrary single direction, and a second path (12b) having nearly the same length, where the current flows in an opposite direction to the first path. The first and second paths (12A and 12B) are adjacent, magnetic fields, generated in the first and second paths (12a and 12b), are canceled for reducing the influence of the magnetic fields, and ideal and stable machining is carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling apparatus for a semiconductor manufacturing apparatus using a thermoelectric element module for cooling and a plasma etching apparatus equipped with the cooling apparatus, and more particularly to electric field and magnetic field conditions in a processing section of the semiconductor manufacturing apparatus. The present invention relates to a cooling device for stabilization and a plasma etching device which is a typical semiconductor manufacturing device equipped with the cooling device.

[0002]

2. Description of the Related Art Conventionally, a plasma etching apparatus for etching a wafer with a plasma gas has been known and is disclosed in, for example, Japanese Patent Application Laid-Open No. 61-238985.

FIG. 19 shows a plasma etching apparatus 101 disclosed in this publication, and a conventional technique will be described below with reference to FIG.

In FIG. 1, a plasma etching apparatus 1
01 is a vacuum chamber 102 in which a reaction gas is sealed.
Is equipped with. Inside the vacuum chamber 102, plasma electrodes 105 and 107 are installed so as to face each other in the vertical direction of the paper surface, and a wafer 106 is mounted on the lower plasma electrode 107.

By applying a high frequency voltage between the upper plasma electrode 105 and the lower plasma electrode 107 by the high frequency power source 103, the reaction gas is ionized to generate the plasma gas between the plasma electrodes 105 and 107 and the wafer 106. To etch.

A thermoelectric module 109 is incorporated inside the lower plasma electrode 107. By passing an electric current from a power source (not shown) to the thermoelectric module 109, the wafer 106 is cooled and the etching depth is controlled.

[0007]

However, the above-mentioned prior art has the following problems. That is, in the conventional thermoelectric module 109, current flows through various paths, so that a magnetic field (not shown) in an irregular direction is generated above the lower plasma electrode 107. Since this magnetic field acts on the ionized plasma gas to distort its movement, there are problems that the etching position shifts and the etching depth changes depending on the location of the wafer 106.

Moreover, since the generated magnetic field acts not only on the plasma but also on the electric field and the charged particles to exert a force, such a processing defect is caused by the plasma etching apparatus 101.
In addition, it is generally generated in a semiconductor manufacturing apparatus that performs processing by applying an electric field, a magnetic field, a high frequency, or the like.

The present invention has been made in view of the above problems, and specifically, for a semiconductor manufacturing apparatus capable of realizing stable processing by reducing a magnetic field generated from a cooling device using a thermoelectric module. It is an object of the present invention to provide a cooling device and a plasma etching apparatus including the cooling device.

[0010]

In order to achieve the above object, the present invention is a cooling device for a semiconductor manufacturing apparatus that is processed in an electric field or a magnetic field, and has a plurality of thermoelectric elements. A thermoelectric module for cooling is provided, and the thermoelectric module has a first electric current flowing in any one direction.
And a second path of substantially the same length in which an electric current flows in the opposite direction to the first path.

According to this structure, the direction vector of the magnetic field generated by the magnetic flux generated by the current flowing through the first path and the direction vector of the magnetic field generated by the magnetic flux generated by the current flowing through the second path Weaken each other on the outside. As a result, since the magnetic field does not leak to the outside of the thermoelectric module, the magnetic field does not distort the electric field or the movement trajectory of the charged particles, and the semiconductor is stably processed under suitable conditions.

Further, in the present invention, it is desirable that the first and second paths are arranged adjacent to each other in the vertical direction and / or the horizontal direction. As a result, the magnetic fields outside the paths generated in the vertical direction and the horizontal direction are more reliably offset, and the electric field and the movement trajectory of the charged particles are not distorted in multiple directions.

Further, in the above invention, it is desirable that each electrode of the first and second paths is divided into two or more perpendicular to the direction of current flow. As a result, the current flowing through the first and second paths is subdivided, so that the maximum strength of the magnetic field generated in the first and second paths can be reduced, and the magnetic field leaking to the outside can be further reduced. .

Another object of the invention is to provide a cooling thermoelectric module having a plurality of thermoelectric elements as another invention relating to a cooling device for a semiconductor manufacturing apparatus which is processed in an electric field or a magnetic field. It is also effectively achieved by disposing a material having a strong magnetic permeability on at least a part of the outer peripheral surface of the module. That is, by disposing a material having a strong magnetic permeability on at least a part of the outer peripheral surface of the thermoelectric module, a part of the magnetic field generated by the current flowing through the thermoelectric module is concentrated inside the material having a strong magnetic permeability. As a result, the magnetic field leaking to the outside is reduced, and changes in the electric field and the movement trajectory of the charged particles can be reduced.

In the above invention, it is desirable to have a modulation wave power supply for supplying a modulation wave current to the current path of the thermoelectric module. For example, when a modulated wave current is applied to a current path of a thermoelectric module from a modulated wave power source that is a combination of a DC power supply and an AC power supply, the magnetic field generated from the thermoelectric module changes with time, and the surrounding susceptor and strong magnetic permeability change. Since an eddy current is generated in the material to cancel the magnetic field, the magnetic field leaking to the outside can be reduced as compared with the case of simply passing a direct current.

Further, in the present invention, it is desirable to further dispose a heat pipe between the thermoelectric module and the metal member around the thermoelectric module. As described above, the eddy current generated by passing the modulated wave current is converted into thermal energy. Therefore, the temperature of peripheral metal members such as a metal susceptor and a material having a strong magnetic permeability in which an eddy current is generated is increased.
As in the present invention, if a heat pipe is further interposed between the thermoelectric module and its surrounding metal members, the amount of heat generated from those metal members is rapidly released to the outside,
The temperature rise of those metal members is effectively prevented.

From the above point of view, a cooling device for a semiconductor manufacturing apparatus, which is processed in an electric field or a magnetic field, is provided with a cooling thermoelectric module having a plurality of thermoelectric elements,
The thermoelectric module includes a first path through which a current flows in any one direction and a second path through which a current flows in an opposite direction to the first path, and at the same time, the thermoelectric module If a material having a strong magnetic permeability is provided on at least a part of the outer peripheral surface of the, the magnetic field leaking to the outside can be further reduced, and more stable processing can be performed.

The invention relating to the cooling apparatus described above is particularly effective when applied to a plasma etching apparatus which is one of semiconductor manufacturing apparatuses, and enables stable plasma etching processing. That is, the distribution of the electric field and the magnetic field in the plasma gas and the movement trajectory of the charged particles are less likely to be distorted by the magnetic field leaking from the electrothermal module that does not contribute to plasma generation, and preferable and stable etching is performed. Needless to say, the cooling device can be applied to other semiconductor manufacturing devices that are processed in an electric field or a magnetic field.

[0019]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. First, the first embodiment will be described. FIG. 1 shows a configuration diagram of a plasma etching apparatus 1 using a cooling device according to this embodiment.

In FIG. 1, a plasma etching apparatus 1
Includes a vacuum chamber 2 in which the inside can be evacuated by a vacuum pump (not shown). A reaction gas having a predetermined composition is filled in the vacuum chamber 2 at a predetermined pressure. Inside the vacuum chamber 2, a pair of flat plate-shaped plasma electrodes 5 and 7 are installed so as to face each other in the vertical direction of the paper surface. The upper plasma electrode 5 is electrically grounded, and the lower plasma electrode is connected to the high frequency power supply 3 via the blocking capacitor 4 and a matching device (not shown).

A wafer is mounted on the lower plasma electrode 7 using a chuck (not shown). By applying a high-frequency voltage between the upper plasma electrode 5 and the lower plasma electrode 7 to apply an electric field, the reactive gas is ionized or dissociated, and the generated plasma gas etches the wafer 6.

The lower plasma electrode 7 is mounted on a metal base called a susceptor 8, and inside the susceptor 8, a thermoelectric module 9 in which a large number of thermoelectric elements are arranged is incorporated. By passing a current through the thermoelectric element via a power source and electrodes (not shown in FIG. 1), the temperature of the cooling side electrode 12 of the thermoelectric element is lowered and the wafer 6 is cooled. This makes it possible to suppress the temperature rise of the plasma gas on the surface of the wafer 6 and perform etching at a predetermined position and a predetermined depth.

FIG. 2 is a block diagram of the thermoelectric module 9 according to this embodiment. The thermoelectric module 9 has a plurality of n-type thermoelectric elements 10 and p-type thermoelectric elements 11 alternately arranged, and the adjacent upper and lower surfaces of the adjacent thermoelectric elements 10 and 11 are the cooling side electrode 12 and the heat radiation side. The electrodes 13 are alternately and sequentially connected. In the embodiment shown in FIG. 2, the two rows of the first thermoelectric module 9a and the second thermoelectric module 9b are arranged adjacent to each other in the width direction to form the thermoelectric module 9.

A current 1 flowing through the first thermoelectric module 9a
4a sequentially flows from the left side to the right side of the drawing from the upper cooling side electrode 12a to the lower heat radiation side electrode 13a through the n-type thermoelectric element 10 and the p-type thermoelectric element 11, and the current 14b of the second thermoelectric module 9a. Is connected to a power source (not shown) so as to sequentially flow from the upper cooling side electrode 12b to the lower heat radiation side electrode 13b from the right side to the left side in the drawing through the n-type thermoelectric element 10 and the p-type thermoelectric element 11. ing. As a result, the upper cooling side electrode 12a of the first thermoelectric module 9a
And the upper cooling side electrode 12b of the second thermoelectric module 9b
Currents 14a and 14b in opposite directions are applied to and.

FIG. 3 shows a distribution state of the magnetic fields 28a and 28b as seen in a cross section taken along the line AA of FIG. In the figure,
A current 14b that flows toward the front of the paper surface flows through the upper cooling-side electrode 12a of the first thermoelectric module 9a, and a current 14b that flows toward the back of the paper surface flows through the upper cooling-side electrode 12b of the second thermoelectric module 9b. As a result, the cooling-side electrodes 12 of the first thermoelectric module 9a and the second thermoelectric module 9b
The magnetic fields 28a and 28b between a and 12b have the same magnetic field direction and the magnetic flux density increases, whereas the magnetic fields 28a and 28b outside the cooling-side electrodes 12a and 12b are:
The directions of the magnetic fields are opposite to each other to cancel each other and the magnetic flux density is reduced.

On the other hand, the decrease rate of the magnetic flux density increases as the difference between the length of the cooling side electrode 12b of the first thermoelectric module 9a and the length of the cooling side electrode 12A of the second thermoelectric module 9b decreases. As a result, the magnetic fields 28a, 28b generated outside along the column direction of the thermoelectric module 9 reduce various influences on the plasma gas, and processing such as etching is suitably and stably performed. This is exactly the same for the heat dissipation side electrodes 13b and 13b.

As shown in FIG. 2, the p-type thermoelectric element 1
A current 17 flowing through 1 flows from the upper cooling side electrode 12 to the lower heat radiation side electrode 13, and a current 16 flowing through the n-type thermoelectric element 10 flows from the lower heat radiation side electrode 13 to the upper cooling side electrode 12. On the other hand, the first and second thermoelectric modules 9a, 9a
In the thermoelectric element arranged in b, the same number of p-type thermoelectric elements 11 and n-type thermoelectric elements 10 are arranged, and the n-type thermoelectric element 1
0 and the p-type thermoelectric element 11 are adjacent to each other.
Therefore, the magnetic field generated by the current 17 of the p-type thermoelectric element 11 flowing from the upper cooling side electrode 12 to the lower radiating side electrode 13, and the n-type thermoelectric element 10 flowing from the lower cooling side electrode 13 to the lower radiating side electrode 12. The magnetic field generated by the current 16 cancels each other out on the outside of the thermoelectric elements 10 and 11, and the magnetic flux density decreases. As a result, the magnetic field generated outside the thermoelectric module 9 is weakened, and the influence on the plasma is reduced.

As described above, according to the first embodiment, the thermoelectric module 9 includes the upper cooling side electrodes 12a, 12
b are adjacent to each other so that the directions of the currents 14a and 14b are opposite to each other. Lower heat radiation side electrodes 13a, 13b
Is also the same. As a result, the magnetic field 28 generated from the currents 14 and 15 flowing through the electrodes 12 and 13 is
The magnetic fields 28 generated outside the thermoelectric module 9 are reduced because they weaken each other outside the thermoelectric modules 2. Therefore, the influence on the plasma gas is reduced, and the processing such as etching is suitably and stably performed.

The cooling side electrode 12 and the heat radiation side electrode 13 of the first thermoelectric module 9a and the second thermoelectric module 9b.
Do not necessarily have to be adjacent to each other, and may be arranged so that current flows in the opposite direction in parallel. However, it is more effective that the magnetic fields 28a and 28b cancel each other more reliably and the magnetic field 28 leaking to the outside is reduced by making the distances as close to each other as possible.

FIG. 4 shows a first arrangement example in which the thermoelectric module according to the first embodiment is arranged on the susceptor 8. In FIG. 4, the arrow indicated by the solid line indicates the first thermoelectric module 9
a array and its cooling side electrode 12a and heat dissipation side electrode 13a
The directions of the currents 14a and 15a flowing through are shown. The arrows indicated by broken lines indicate the arrangement of the second thermoelectric modules 9b and the directions of the currents 14b and 15b flowing through the cooling side electrodes 12b and the heat radiation side electrodes 13b thereof.

That is, the first thermoelectric module 9a is drawn into the surface of the susceptor 8 from the outside toward the substantial center of the susceptor 8 at the start end portion, and is made to make a full clockwise rotation along the outermost peripheral edge of the susceptor 8. The second thermoelectric module 9b is formed by arranging one stage and arranging a required number of thermoelectric elements 10 and 11 toward the approximate center of the susceptor 8 at the end portion on the side where the currents 14a and 15a flow, and then forming the connecting portion. The first thermoelectric module 9a of the first stage is arranged adjacent to the inner peripheral side so as to make one round in a counterclockwise direction, and at the end of the side where the currents 14b and 15b flow is located approximately in the center of the susceptor 8. After arranging a required number of thermoelectric elements 11 and 10 toward each other to form a connecting portion, the second thermoelectric module 9a at the second stage is further arranged clockwise, and the second thermoelectric module 9a at the second stage is further arranged inside thereof. Thermoelectric module With placing the 9b counterclockwise,
The first thermoelectric module 9a and the second module 9b are arranged so as to be pulled out to the outside between the terminal connection portions. The electrode 12a at the starting end of the first thermoelectric module 9a and the electrode at the end of the second thermoelectric module 9b can be connected to a power source (not shown).

As shown in FIG. 4, the first thermoelectric module 9
In a, the currents 14a and 15a flow clockwise in the horizontal plane, whereas in the second thermoelectric module 9b, the currents 14a and 15b flow counterclockwise, which is the opposite direction. As a result, the magnetic field h generated from the currents 14 and 15 weakens each other outside the thermoelectric module 9 and becomes smaller, and the influence of the magnetic field on the plasma gas becomes smaller.

Further, as is apparent from FIG. 4, the connecting portion between the first and second thermoelectric modules 9a and 9b, which are arranged in two stages on the susceptor 8 in a circular shape, are drawn in and out from the outside. The electric currents flowing through the respective thermoelectric elements 10 and 11 are opposite to each other as indicated by the solid arrow 18a and the broken arrow 18b. That is, the current 18a
Indicates that the surface of the paper is upward and the current 18b flows in the opposite direction of the paper and downward. The magnetic fields generated by the electric currents 18a and 18b also weaken each other outside the electrodes, and the magnetic field exerts a small influence on the plasma gas. is doing.

FIG. 5 shows a second arrangement example in which the thermoelectric module 9 according to the first embodiment is arranged on the susceptor 8. In this figure, the solid arrow indicates the first thermoelectric module 9
The current direction flowing through the p-type and n-type thermoelectric elements 11 and 12 of a is shown, and the broken line arrow shows the current direction flowing through the n-type and p-type thermoelectric elements 10 and 11 of the first thermoelectric module 9a.

According to this arrangement example, a part of the first thermoelectric module 9a introduced toward substantially the center of the susceptor 8 is arranged along a part of the peripheral portion of the susceptor 8 and then the connecting portion. Is connected to the second thermoelectric module 9b through the second thermoelectric module 9b, the second thermoelectric module 9b is arranged in the string direction, and then connected to the first thermoelectric module 9a, and the first thermoelectric module 9a is connected through the connecting portion to the second thermoelectric module 9a. It is arranged so as to extend in the chord direction in the opposite direction to the module 9b, and this arrangement is repeated several times.
After being linearly arranged from the center side to the peripheral edge, the second thermoelectric module 9b is arranged along the outermost peripheral edge portion of the susceptor 8.

In the thermoelectric module 9 arranged in this way, as shown in FIG. 5, currents 14a, 15a, 18a in the directions indicated by solid arrows on the first thermoelectric module 9a flow, and in the second thermoelectric module 9b. The currents 14b, 15b, 18b flow in the directions indicated by the dashed arrows. That is, the currents 14 and 15 flow in opposite directions in the first thermoelectric module 9a and the second thermoelectric module 9b that are adjacent to each other. As a result, the current 14 flowing through each electrode 12, 13
The magnetic fields generated from 15 weaken each other outside the thermoelectric module 9, and the effect of the magnetic field on the plasma gas is small, so that accurate and stable etching can be performed.

Further, even in this arrangement example, the susceptor 8 is
First thermoelectric module 9a and first and second introduced into
A current 18a flowing through each part of the first thermoelectric module 9a connecting the thermoelectric modules 9a and 9b, a second thermoelectric module 9b derived from the susceptor 8 and a second thermoelectric element arranged on the outermost peripheral edge of the susceptor 8. Since the electric currents 18a flowing in the module 9b and the electric currents 18a flowing in the respective directions are opposite to each other, the magnetic fields weaken each other outside the electrodes 12 and 13, and the influence of the magnetic fields on the plasma gas is reduced.

FIG. 6 shows an experimental result of a magnetic field generated in the radial direction on the wafer (susceptor) when cooled by the thermoelectric module 9 of the first embodiment. The measurement values in the figure are 5 mm above the susceptor when a direct current of 5 A is applied to the thermoelectric module, and the scalar quantity of the magnetic flux density at an arbitrary linear upper position on the conductor of the thermoelectric module passing through the center of the susceptor and under the same conditions. The numerical analysis results of are compared and displayed.

As can be seen from the figure, fluorescence that agrees with the analysis results is generally seen, and the generated magnetic field strength is 0.206.
Gauss. This result was 0.226 obtained by analysis.
It is in good agreement when compared with Gauss. From this,
The effect of reducing the magnetic flux density of the thermoelectric module 9 according to this embodiment was verified.

FIG. 7 shows a schematic structure of a thermoelectric module 9 according to the second embodiment of the present invention. Also in the thermoelectric module 9 shown in the figure, as in the first embodiment, the p-type thermoelectric elements 11 and the n-type thermoelectric elements 10 are alternately arranged, and the upper and lower portions of the thermoelectric elements 10 and 11 are connected to each other. To
The upper cooling side electrode 12 and the lower cooling side electrode 13 are alternately connected.

The thermoelectric module 9 according to this embodiment has, in addition to the above configuration, a portion above the upper cooling-side electrode 12 and a lower heat-radiating side electrode 13 for connecting the thermoelectric elements 10 and 11 together.
In the lower part of the above, a long flat plate-shaped upper electrode 19 and a lower electrode 20 are arranged in parallel with the upper cooling side electrode 12 and the lower heat radiation side electrode 13 via columnar electrodes 21b, 21b. Although not shown, a space 2 between the upper electrode 19 and the upper cooling-side electrode 12 and between the lower heat-radiating-side electrode 13 and the lower electrode 20 is provided in order to enhance thermal conductivity.
An insulator is inserted in each of 7 and 27. Further, in this embodiment, the lower electrode 20 is connected to the-side of the DC power source 22, and the upper electrode 19 is connected to the + side of the DC power source 22 via the columnar electrode 21a.

According to this embodiment, as shown in FIG.
The upper electrode 19 and the cooling side electrode 12 are installed parallel to each other, and a current 23 flowing through the upper electrode 19 and a current 14 flowing through the cooling side electrode 12 flow in directions opposite to each other. As a result, the magnetic fields generated from the upper electrode 19 and the upper cooling side electrode 12 weaken each other outside the electrodes 12 and 19 and reduce the influence of the magnetic field on the plasma gas. This phenomenon is the same between the current 15 flowing through the lower heat radiation side electrode 13 and the current 24 flowing through the lower electrode 20.

Further, the current 25 flowing through the columnar electrode 21a connected to the + side of the DC power source 22 and the current 26 flowing through the two columnar electrodes 21b coupled to the lower electrode 20 and the lower electrode 13 are opposite to each other. The magnetic field generated by the current flowing through each of the columnar electrodes 21a and 21b is
They weaken each other outside the columnar electrodes 21a and 21b.

As described above, according to the second embodiment, the upper electrode 19 and the lower electrode 20 are opposed to the upper cooling side electrode 12 and the lower discharge heat side electrode 13, respectively. The current 14 flowing through the upper cooling side electrode 12 and the current 23 flowing through the upper electrode 19 flow in mutually opposite directions, and the same applies to the lower heat radiation side electrode 13 and the lower electrode 20 which face each other. As a result, similarly to the first embodiment, the magnetic fields generated from the currents 14, 15, 23, 24 are offset and weakened on the outside of the electrodes 12, 13, 19, 20, and the magnetic fields affect the plasma gas. Becomes smaller, and etching is performed favorably and stably.

FIG. 8 shows a thermoelectric module 9 of the present invention according to the second embodiment described above and a conventional thermoelectric module designed to flow all currents in one direction as a cooling device for a plasma etching apparatus. The distribution state of the magnetic flux density in the region 10 mm above the susceptor 8 when used is shown. As can be understood from this figure, the maximum magnetic flux density in the central portion of the susceptor is approximately 1.35 gauss in the conventional thermoelectric module, whereas it is approximately 0.79 gauss in the thermoelectric module 9 of the present invention. The magnetic flux density of the thermoelectric module 9 of the present invention is almost twice as low as the conventional one.

Further, the susceptor has a diameter of 0.
The magnetic flux density generated by the conventional thermoelectric module fluctuates between 0.3 and 0.75 gauss up to the portion separated by 07 m, whereas the thermoelectric module 9 of the present invention has a magnetic flux density of approximately 0.01-. It can be seen that the density fluctuates between 0.19 gauss and the density of the generated magnetic flux is significantly reduced in the entire region of the susceptor.

9 and 10 show first and second modified examples of the thermoelectric module 9 according to the second embodiment. In the modification shown in FIG. 9, the thermoelectric module 9
Is one stage as in the second embodiment, but unlike the second embodiment, a lower electrode 20 extending in the length direction is arranged below the thermoelectric module 9 and upper cooling arranged at an end portion. The side electrode 12 and the lower electrode 20 are connected by a columnar electrode 21. Further, an insulating plate 20a made of ceramics or the like is interposed in a gap between the lower heat radiation side electrode 13 of the thermoelectric module 9 and the lower electrode 20.

Therefore, the magnetic fields generated by these electrodes 12, 13, 20 cancel each other out and weaken each other, and the magnetic flux generated outside the thermoelectric module 9 is reduced. In addition, a current 25 flowing downward in the plane of the drawing flows through the columnar electrodes 21 and the adjacent n
Since the electric current 16 flows upward in the drawing on the thermoelectric element 11 of the mold, the magnetic fields are weakened outside the columnar electrodes 21a and 21b.

In the modification shown in FIG. 10, the thermoelectric module 9 is constructed by stacking a plurality of thermoelectric modules 9 in a multi-tiered manner in the vertical direction. Thermoelectric module 9 according to this modification
As in FIG. 6, the uppermost upper electrode 19 and the cooling-side electrode 12 of the uppermost thermoelectric module 9 face each other with a short distance therebetween, and currents 14 and 23 flow in directions opposite to each other.
In addition, the heat dissipation side electrode 13 of the thermoelectric module 9 at the top,
Similarly, the cooling side electrode 12 of the thermoelectric module 9 in the lower stage is opposed to each other, and currents 14 and 15 flow in directions opposite to each other. The same applies to the electrodes 12, 13, 19, 20 of the other stages.

Therefore, these electrodes 12, 13, 19,
The magnetic fields generated outside 20 cancel each other out and weaken,
The magnetic flux generated outside the thermoelectric module 9 is reduced.
Further, since a current 25 that flows upward in the plane of the drawing flows through the columnar electrode 21a and a current 26 that flows downward in the plane of the drawing flows through the columnar electrode 21b, the magnetic fields are weakened outside the columnar electrodes 21a and 21b.

As described above, the thermoelectric modules 9 according to the present invention are arranged in multiple rows in the horizontal direction as in the first embodiment or in multiple rows in the vertical direction as in the second embodiment. The number is not limited, and it is also possible to arrange in multiple stages in both the vertical and horizontal directions. In any case, in the thermoelectric modules obtained by arranging them in that direction, the direction of the current flowing in a current path that is adjacent to the current path flowing in one direction flows in the opposite direction to the one direction. It is essential to configure it as follows.

Further, as the current flowing in the reverse direction, the feedback current of the current flowing in the one direction may be used as in the second embodiment described above. The effect can be obtained.

FIG. 11 schematically shows the schematic structure of a thermoelectric module according to the third embodiment of the present invention. The basic structure of the thermoelectric module 9 according to this embodiment is that a plurality of n-type thermoelectric elements 10 and p-type thermoelectric elements 11 are alternately arranged and the adjacent thermoelectric elements are arranged in the same manner as in the first example. The upper and lower surfaces of the elements 10 and 11 are alternately and sequentially connected by the cooling side electrodes 12 and the heat radiation side electrodes 13. The current 14 flowing through the thermoelectric module 9 is n
It is connected to a power source (not shown) so as to sequentially flow from the upper cooling side electrode 12 to the lower heat radiation side electrode 13 from the right side to the left side of the drawing through the die thermoelectric element 10 and the p type thermoelectric element 11.

Here, the difference between this embodiment and the first embodiment is that a slit-like shape that is long in the direction in which the currents 14 and 15 flow is formed in both the plate-shaped upper cooling-side electrode 12 and the lower heat-dissipating-side electrode 13. The point is that a plurality of elongated holes 12c and 13c are formed in a direction orthogonal to the direction in which the currents 14 and 15 flow. As described above, by subdividing the currents 14 and 15 flowing through the upper cooling side electrode 12 and the lower heat radiation side electrode 13 into a plurality of slit-shaped long holes 12c and 13c, the upper cooling side electrode 12 and the lower heat radiation side electrode 13 are separated. Since a plurality of parallel currents will flow and the magnetic field strength generated from each will also be small, the peak value of the magnetic field strength as a whole can be lowered. As a result, for example, the adverse effect of the magnetic field generated from the thermoelectric module 9 on the plasma gas is significantly reduced, and suitable and stable etching can be performed.

FIG. 12 shows a change in magnetic flux of the generated magnetic field in the radial direction during cooling of the wafer (susceptor) by the thermoelectric module 9 of the third embodiment and the conventional thermoelectric module. As you can see from the figure, 200m
The maximum magnetic flux density at the central portion and the peripheral edge of a wafer (susceptor) having an m diameter exceeds approximately 3.5 Gauss in the conventional thermoelectric module, whereas the thermoelectric module 9 of the present invention.
However, the magnetic flux density of the thermoelectric module 9 according to the present embodiment is significantly smaller than that of the conventional one.

In addition, the center of the susceptor is 0.
The magnetic flux density generated by the conventional thermoelectric module fluctuates between 0.3 and 1.7 gauss even between the parts separated by 07 m, whereas the thermoelectric module 9 of the present invention
It can also be understood that the density of the generated magnetic flux is significantly reduced in the entire region of the susceptor because the value fluctuates between approximately 0.2 and 0.75 gauss.

FIG. 13 schematically shows a thermoelectric module according to the fourth embodiment of the present invention. Also in this thermoelectric module 9, a plurality of n-type thermoelectric elements 10 and p-type thermoelectric elements 11 are alternately arranged, and the adjacent upper and lower surfaces of the adjacent thermoelectric elements 10 and 11 are cooled side electrodes. 1
2 and the heat dissipation side electrode 13 are used as a normal structure which is alternately and sequentially connected. The current 14 flowing through the thermoelectric module 9 passes from the upper cooling side electrode 12 to the lower heat radiation side electrode 1 via the n-type thermoelectric element 10 and the p-type thermoelectric element 11.
3 is connected to a power source (not shown) so as to sequentially flow in one direction from the right side to the left side in the drawing.

In this embodiment, in addition to the above-mentioned structure, the entire surface of the thermoelectric module 9 is covered with a permalloy 29 which is a material having a high magnetic permeability. The high magnetic permeability material is not limited to the permalloy, and examples thereof include sendust and various ferrites.

As described above, when the entire surface of the thermoelectric module 9 is covered with a high magnetic permeability material, the thermoelectric module 9
The magnetic flux generated by the current 14 flowing in the magnetic field concentrates on the high magnetic permeability material, and significantly reduces the magnetic flux leaking to the outside of the thermoelectric module 9. As a result, for example, the distribution of the electric field and magnetic field in the plasma gas and the movement trajectory of the charged particles are
It is less likely to be distorted by the magnetic field leaking from the electric heating module 9, and suitable and stable etching can be performed.

FIG. 14 schematically shows a thermoelectric module according to the fifth embodiment of the present invention. In the present embodiment, as shown in FIG. 7A, the upper surface and the peripheral surface of a single thermoelectric module 9 having a normal structure are provided with a permalloy 29 as in the fourth embodiment. The thermoelectric module 9 ′ is coated with such a high magnetic permeability material, and the DC power source 30 and the high frequency power source 31 are connected in series to the terminals of the thermoelectric module 9 so that the modulated wave as shown in FIG. The current 32 is made to flow.

When the modulated wave current 32 is made to flow to the thermoelectric module 9 in this way, the amount of the current 32 flowing with the passage of time changes, and the magnetic flux density of the magnetic field generated there also changes, resulting in high permeability. Generate eddy currents in magnetic susceptibility material. The magnetic field generated by this eddy current also reduces the magnetic flux density of the magnetic field leaking to the outside of the thermoelectric module 9. As a result, the magnetic field shielding function of the high-permeability material is improved, and suitable and stable etching can be performed even in the plasma gas.

FIG. 15 shows a schematic structure of a cooling device according to a sixth embodiment of the present invention in cross section, and FIG. 16 schematically shows a thermoelectric module used in the cooling device. In the present embodiment, the upper surface and the peripheral surface of the thermoelectric module 9 having the same configuration as the first embodiment is covered with the heat pipe 33, and the upper surface and the peripheral surface of the heat pipe 33 are further covered. Similar to the fourth embodiment described above, the modulated wave current 32 is applied to the thermoelectric module 9 by covering it with the permalloy 29 and connecting the DC power source 30 and the high frequency power source 31 to the terminals of the thermoelectric module 9 in series. I am trying. Further, on the lower surface side of the thermoelectric module 9, there is further arranged a cooling portion 34 by a cooling medium 34a such as water or garten.

In general, as described above, when an eddy current is generated, it is converted into heat energy, so that the temperature of the metal generating the eddy current, that is, the permalloy 29 in this embodiment, rises.
Therefore, the permalloy 29 is rapidly cooled by the heat pipe 33 to ensure the cooling function by increasing the temperature. By adopting such a configuration,
Since the respective functions exerted by the cooling devices according to the first to fourth embodiments are synergistically exerted and the magnetic field leaking to the outside is almost eliminated, for example, extremely stable etching can be performed even in plasma. You will be able to do it. Moreover, since the cooling portion 34 by the cooling medium is provided on the lower surface of the thermoelectric module 9, heat can be efficiently exchanged with the thermoelectric module 9, which is effective for a wafer (not shown). Can be cooled.

FIG. 17 shows a modification of the cooling device according to the sixth embodiment. In this modification, in place of the permalloy 29 provided on the entire upper surface and the peripheral side surfaces of the heat pipe 33 that covers the upper surface and the peripheral side surface of the thermoelectric module 9, permalloy 29 and good thermal conductivity such as copper or aluminum. The material 35 and the material 35 are alternately arranged on the concentric circles. The permalloy 29 and the good thermal conductive material 35 are alternately fitted with a plurality of ring-shaped permalloys 29 and the good thermal conductive material 35 having different diameters.
The permalloy 29 arranged at the second position is formed in a cylindrical shape with an inner flange provided at one end on the inner diameter side, and the permalloy 29 arranged on the outermost periphery and the good heat conductive material 35 arranged inside thereof.
Are each formed into a cylindrical shape and are sequentially fitted to each other. By adopting such a configuration, the magnetic force lines of the magnetic field generated by the current 32 flowing through the thermoelectric module 9 can be reduced and at the same time the thermal conductivity is improved, so that the heat exchange between the susceptor 8 and the wafer (not shown) can be performed. This will be done promptly and the cooling efficiency will be improved.

FIG. 18 shows an example of the plasma etching apparatus 1 to which the cooling device according to the seventh embodiment of the present invention is applied. In the figure, in the cooling device, various thermoelectric modules 9 as described in the above-described embodiment are provided inside the susceptor 8 and also attached to the outer wall of the vacuum chamber 2 so that the wafer 6 on the susceptor 8 is attached. At the same time as cooling, the inside of the vacuum chamber 2 is also actively cooled. At this time, the power source for the thermoelectric module 9 may be a mere DC power source, but it is desirable to use a modulated wave power source as in the sixth embodiment.

As described above, if the thermoelectric module 9 of the present invention is used to positively cool not only the wafer 6 but also the wall surface of the vacuum chamber 2 and the inside thereof, the magnetic field generated from the thermoelectric module 9 is weak. The plasma gas is not affected and the etching is carried out favorably and stably.

Although the plasma etching apparatus 1 is shown to include parallel plate type plasma electrodes 5 and 7 in the drawings, the present invention is not limited to this. For example, at least one plasma electrode is A coil shape or an antenna shape may be used. Further, both plasma electrodes can be connected to a high frequency power supply without grounding one plasma electrode. Furthermore, plasma may be generated in a state where a magnetic field is applied in the vacuum chamber 2 by using a permanent magnet or the like.

Further, in the above description, the plasma etching apparatus for performing the etching with the plasma gas has been described, but the present invention is applicable not only to the etching apparatus but also to all semiconductor manufacturing apparatuses using plasma. Further, not only for semiconductor manufacturing equipment using plasma, but also for all semiconductor manufacturing equipment that processes semiconductors by applying an electric field, such as electron beam drawing equipment using charged particles such as electron beams. It can be applied.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration example of a plasma etching apparatus using a cooling device according to a first embodiment of the present invention.

FIG. 2 is a perspective view schematically showing a configuration example of a thermoelectric module used in the cooling device according to the first embodiment.

FIG. 3 is an explanatory diagram of a magnetic field as seen in a cross section taken along line AA of FIG.

FIG. 4 is a plan view schematically showing an arrangement example of thermoelectric modules according to the first embodiment.

FIG. 5 is a plan view schematically showing a second arrangement example of the thermoelectric module according to the first embodiment.

FIG. 6 is an explanatory diagram showing an experimental value and an analytical value of a change in magnetic flux density of a magnetic field generated in a radial direction when a wafer (susceptor) is cooled by the arrangement of the thermoelectric module of the first embodiment.

FIG. 7 is a perspective view schematically showing a configuration example of a thermoelectric module applied to the cooling device according to the second exemplary embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a distribution state of magnetic flux density during cooling using the thermoelectric module according to the second embodiment and a conventional thermoelectric module.

FIG. 9 is a perspective view showing a first modified example of the thermoelectric module according to the second embodiment.

FIG. 10 is a side view showing a second modification of the thermoelectric module according to the second embodiment.

FIG. 11 is a perspective view schematically showing a configuration example of a thermoelectric module applied to the cooling device according to the third exemplary embodiment of the present invention.

FIG. 12 is an explanatory diagram showing a change in magnetic flux of a generated magnetic field in a radial direction when a wafer (susceptor) is cooled by the thermoelectric module of the third embodiment and a conventional thermoelectric module.

FIG. 13 is a perspective view schematically showing a configuration example of a thermoelectric module applied to the cooling device according to the fourth exemplary embodiment of the present invention.

FIG. 14 is an explanatory diagram showing a configuration example of a thermoelectric module applied to a cooling device according to a fifth embodiment of the present invention and a current waveform thereof.

FIG. 15 is a sectional view schematically showing a configuration example of a cooling device according to a sixth exemplary embodiment of the present invention.

FIG. 16 is a perspective view schematically showing a thermoelectric module section applied to the apparatus.

FIG. 17 is a cross-sectional view schematically showing a modified example of the cooling device according to the sixth exemplary embodiment.

FIG. 18 is a sectional view showing a schematic configuration of a plasma etching apparatus provided with a cooling device of the present invention.

FIG. 19 is a sectional view showing a schematic configuration of a plasma etching apparatus according to a conventional technique.

[Explanation of symbols]

1 Plasma etching equipment 2 vacuum chamber 3 high frequency power supply 4 capacitors 5 Upper plasma electrode 6 wafers 7 Lower plasma electrode 8 susceptor 9 Thermoelectric module 10 n-type thermoelectric element 11 p-type thermoelectric element 12,12a, 12b Upper cooling side electrode 13,13a, 13b Lower heat dissipation side electrode 12c, 13c slit-shaped long holes 14-18 current 18a, 18b current 19 Upper electrode 20 Lower electrode 21a, 21b Columnar electrodes 22 DC power supply 23-26 current 27 spaces 28 magnetic field 29 Permalloy (high permeability material) 30 DC power supply 31 high frequency power supply 32 Modulation wave current 33 heat pipe 34 Cooling unit 34a Cooling medium 35 Good thermal conductive material

Claims (8)

[Claims] 1. A cooling device for a semiconductor manufacturing apparatus that is processed in an electric field or a magnetic field, comprising a thermoelectric module (9) for cooling having a plurality of thermoelectric elements, wherein the thermoelectric module (9) is A first path (12a) through which current flows in any one direction, and a second path (12b) of substantially the same length through which current flows in the opposite direction to the first path (12a). A cooling device for a semiconductor manufacturing apparatus, which comprises: 2. The first and second paths (12a, 12)
The cooling device according to claim 1, wherein b) is arranged adjacently in the vertical direction and / or the horizontal direction. 3. The first and second paths (12a, 12)
The cooling device according to claim 1 or 2, wherein each electrode of (b) is divided into two or more perpendicular to the current flow direction. 4. A cooling device for a semiconductor manufacturing apparatus which is processed in an electric field or a magnetic field, the cooling thermoelectric module (9) having a plurality of thermoelectric elements.
A cooling device for a semiconductor manufacturing apparatus, characterized in that a material having a high magnetic permeability is disposed on at least a part of an outer peripheral surface of the thermoelectric module (9). 5. The modulation wave power source for flowing a modulation wave current through the current paths (12a, 12b) of the thermoelectric module (9), according to claim 1. Cooling system. 6. The cooling device according to claim 4, wherein a heat pipe is arranged between the thermoelectric module (9) and the high magnetic permeability material. 7. A cooling device for a semiconductor manufacturing apparatus which is processed in an electric field or a magnetic field, comprising a thermoelectric module (9) for cooling having a plurality of thermoelectric elements, wherein the thermoelectric module (9) is , A first path (12A) through which an electric current flows in any one direction, and the first path (12A).
and a second path (12b) of substantially the same length in which an electric current flows in the opposite direction to a), and a material having a high magnetic permeability is disposed on at least a part of the outer peripheral surface of the thermoelectric module (9). A cooling device for a semiconductor manufacturing apparatus, characterized in that 8. A plasma etching apparatus comprising the cooling device according to claim 1.