JP2015057504A - Processing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing unit excellent in cooling performance.SOLUTION: A processing unit includes a substrate loading part capable of loading a substrate thereon, holding means for holding the substrate on the substrate loading part by generating a pressing force between itself and the substrate loading part, cooling means for cooling the substrate loading part, and rotating means for rotating the substrate loading part together with the cooling means. Further, a vibration isolating member is arranged on the peripheral part of an elastic body of the cooling means.

Description

  The present invention relates to a processing apparatus equipped with a refrigerator for cooling a substrate.

  Conventionally, a method of performing sputtering while maintaining a substrate at a low temperature is known for controlling crystal growth and the like. For example, the possibility of forming an amorphous film can be expected by forming the substrate at a low temperature (for example, a minus region). This is because the sputtered particles adhere to the substrate and at the same time lose energy by the low-temperature substrate, and the surface movement of the particles can be suppressed.

Further, not limited to film formation by a sputtering apparatus, according to Non-Patent Document 1, it has been reported that, in the manufacture of semiconductor integrated circuit devices, the processing dimensional accuracy is improved by application to etching at a liquid nitrogen temperature or lower. Yes.
Thus, in order to realize processes such as sputtering and etching in a low temperature region, low temperature control of a substrate holder (hereinafter referred to as a substrate mounting portion) is necessary.

  In Patent Document 1, a substrate is fixed to the substrate platform by connecting a refrigerator to the substrate platform and providing a cooling gas exhaust hole in the recess of the substrate platform to exhaust the cooling gas. There has been disclosed a sputtering apparatus provided with a substrate mounting portion that can ensure reproducibility without being increased, suppress the in-plane distribution of the substrate temperature, and cool to a target temperature.

  Here, as an example of the refrigerator connected to the substrate mounting portion, FIG. 3 shows a free piston type Stirling cycle-use refrigerator (reference numeral 300), which will be briefly described below with reference to FIG.

  When a piston 310 is reciprocated in the direction of arrow a by operating a linear motor constituted by a coil 310 that is connected to the cable 340 and through which an alternating current of a predetermined frequency flows and a cylindrical permanent magnet 311, a working gas (freezing The pressure in the machine casing 301 changes (isothermal compression, isothermal expansion), and the displacer 313 reciprocates with the piston 312 with a phase difference.

  At this time, the piston 312 held by the leaf spring 360 which is an elastic body is provided separately from the shaft 314 and the displacer 313 held by the leaf spring 350 so as to be movable in the arrow a direction. These leaf springs stabilize the reciprocating motion of the displacer and piston in the direction of arrow a.

As a result, while the high-pressure working gas moves through the compression space 320 to the heat radiation part 321 to the regeneration part 323 to the heat absorption part 322 to the expansion space 324, the heat absorption by the heat absorption part 322 and the heat radiation by the heat radiation part 321 are performed (etc. Volume change) A Stirling cycle is formed. The heat absorbing unit 322 cools the object to be cooled (not shown) by absorbing heat from the object to be cooled (not shown).
The heat absorption part 322 may be connected to the refrigeration head 330 to increase the contact area with an object to be cooled (not shown). The absorbed heat is conducted to the heat radiating unit 321 through the reproducing unit 323 and radiated.

  In this way, by reciprocating the piston and the displacer, a reversible cycle consisting of isothermal compression and isothermal expansion due to pressure change of the working gas and heat absorption and heat dissipation due to equal volume change when the working gas flows is performed. The periphery of the endothermic part is cooled to a low temperature, and the object to be cooled is cooled by bringing the endothermic part into contact with the object to be cooled.

International Publication No. WO2011 / 043063

J. Plasma FusionRes. Vol.83, No.4 (2007) 319-324

  However, in vacuum processing such as sputtering and etching as described above, a free piston type Stirling cycle is used for the substrate mounting portion on which the object to be processed is mounted in order to execute a highly useful low temperature process in the vacuum processing apparatus. Therefore, it is necessary to protect the substrate mounting portion from the vibrations transmitted from the refrigerator.

  In other words, the vibration of the substrate placement unit reduces the stability of mechanically pressing the substrate to the substrate placement unit, and the substrate placement is performed even if the substrate does not fall from the substrate placement unit during the low temperature process. As a result, there is a risk of causing a transport trouble (dropping of the substrate, etc.) during transport in the vacuum processing apparatus following the low temperature process.

  Furthermore, when the substrate mounting portion is rotated together with the refrigerator, there is a possibility that periodic or irregular lateral blurring (swaying from the center of the rotating shaft of the refrigerator in the radial direction) due to the rotation of the refrigerator occurs. In addition, the instability of holding the substrate on the substrate mounting portion further increases.

  That is, in order not to impair the transport reliability of the substrate on the substrate platform, it is necessary to take a vibration-proof measure for the substrate platform that is maintained at a low temperature. In addition, the lateral blur is a problem that affects the reciprocating motion of the displacer and the piston that are periodically performed in the refrigerator, and may also reduce the refrigeration capacity of the refrigerator itself.

  An object of the present invention is to provide a processing apparatus using a free piston type Stirling cycle refrigerator as a cooling means that can cool a substrate on a substrate mounting portion rotatable in the processing apparatus to an extremely low temperature. In particular, an object of the present invention is to provide a processing apparatus capable of reducing vibrations generated from the refrigerator by simple adjustment.

According to the processing apparatus of the first aspect of the present invention, the substrate mounting portion capable of mounting the substrate, the holding means for holding the substrate on the substrate mounting portion, and the cooling for cooling the substrate mounting portion. A processing apparatus comprising: means; and a rotating means for rotating the substrate mounting portion and the cooling means on the same axis,
The cooling means has an elastic body on the same axis, and a vibration isolating member is disposed around the rotation axis of the elastic body.
Further, the elastic body is disk-shaped and is characterized in that a vibration isolating member is disposed on the peripheral edge thereof.
Furthermore, the vibration isolating members are arranged at equal intervals.

  In this way, by adopting a configuration in which the refrigerator is connected to the substrate platform, the substrate of the substrate platform can be cooled to a cryogenic temperature such as 100K or less, and the radial direction of the displacer of the refrigerator ( Since the vibration isolating member is arranged in the radial direction of the rotating shaft of the refrigerator main body, the radial rigidity of the elastic body at the time of rotation can be further increased, and lateral blur that increases due to the rotation of the refrigerator can be reduced. .

  By using the processing apparatus according to the present invention, a refrigerator connected to the substrate mounting unit while the substrate mounting unit is rotating or even while performing a process such as film formation by sputtering, Sufficient cooling capacity (substrate temperature of 100K or less) can be realized, and further, the occurrence of lateral blur caused by the rotation of the refrigerator is suppressed, the substrate is held so as not to be displaced, or the displacement is prevented. Therefore, the stability of conveyance can be maintained.

It is a figure which shows an example of the processing apparatus which concerns on this embodiment. It is the side view and rear view of a refrigerator which are arrange | positioned at the processing apparatus which concerns on this embodiment. It is a top view of one Example of the refrigerator arrange | positioned at the processing apparatus which concerns on this embodiment. It is a general view of the experimental machine used for the cooling experiment which concerns on this embodiment.

  FIG. 1 is a diagram illustrating an example of a sputtering apparatus as an example of a processing apparatus according to the present embodiment. The sputtering apparatus 100 includes a cathode 103, a target 104, a cathode magnet 102, and a substrate placement unit 122 in a vacuum container 101.

  A process gas (sputtering gas, etc.) introduced via a process gas pipe 111 from a gas cylinder (not shown) via a flow rate controller (mass flow controller) 110 can be introduced into the vacuum vessel 101, and impurity gas is exhausted. An exhaust mechanism 112 such as a turbo molecular pump is provided.

  The cathode 103 is connected to a high-frequency power source 107 and a DC power source 108 via a matching unit 106, for example. As a result, the cathode 103 can be supplied with power only from the high-frequency power source 107, supplied by superimposing the high-frequency power source 107 and the DC power source 108, or supplied only from the DC power source 108. Of course, the matching unit 106 and the high-frequency power source 107 may be omitted and only the DC power source 108 may be used.

  The substrate platform 122 is provided with a substrate holding ring 120 as a holding unit, and the substrate W can be pressed against the substrate platform 122 and fixed. A refrigerator 132 as a cooling unit is connected to the lower part of the substrate platform 122 via a refrigeration head 130. The refrigerator 132 is, for example, a type using a Stirling cycle. Furthermore, a vibration isolator 180 according to the present invention is connected to the lower part of the refrigerator 132. The description of the vibration isolator 180 will be described later.

The refrigerator 132 using the Stirling cycle generates a cryogenic temperature by adiabatic expansion by helium gas and piston movement built in the refrigerator 132. For this reason, piping for feeding helium gas into the refrigerator is not connected to the refrigerator 132, and a drive power supply (for a linear motor for piston motion, etc.) of the refrigerator 132 and electrical wiring for temperature adjustment Only need to be connected.
Note that the electrical wiring for temperature adjustment or the like is, for example, a resistance heating element connected to the back surface of the substrate platform 122. Since these wirings can be easily supplied using a current collecting ring (slip ring) 134, the structure becomes very simple.

For this reason, the substrate fixed to the substrate platform 122 and the substrate platform 122 while performing a rotation operation by installing the refrigerator 132 using the Stirling cycle in the rotatable substrate platform 122. It becomes possible to cool W.

On the other hand, the refrigerator 132 is fixed to the rotary base assembly 133. The rotating base assembly 133 is inserted into the magnetic fluid seal 142, and the magnetic fluid seal 142 is fixed to the vertical drive base 141.
In addition, the refrigerator 132 includes a radiator 131 made of an annular metal as a heat exhaust mechanism for discharging heat generated by the refrigerator itself to the outside of the refrigerator main body.

  The radiator 131 is fixed to the refrigerator 132, and a refrigerant such as water is introduced into the inside of the radiator 131 via an air-side refrigerant external pipe 144 disposed below the rotary base assembly 133. It is possible to flow through the radiator 131 and the refrigerant internal pipe 151 in this order (flow directions in the rotary base assembly 133 are shown in the order of reference numerals 172, 173, 174, and 175).

  A coolant such as water that has flowed through the radiator 131 introduced from the coolant external pipe 144 is discharged to the atmosphere side from the coolant external pipe 145 disposed at the lower portion of the rotating base assembly 133. A refrigerant such as water is caused to flow through the radiator 131 that rotates together with the refrigerator 132 and is exhausted through the refrigerant, so that the refrigerating capacity can be maintained without accumulating heat in the refrigerator 132.

Accordingly, the substrate platform 122, the refrigeration head 130, the refrigerator 132, the radiator 131, and the rotating base assembly 133 are fixed to each other, and a motor that is a rotating means for rotating the rotating base assembly 133. 143 is disposed, and the substrate W placed on the substrate platform 122
In this case, the rotation base assembly 133 and the like can be coaxially rotated by the motor 143, that is, can rotate around the common rotation shaft 160 (the rotation direction is indicated by reference numeral 161).

  Since the vertical drive base 141 is fixed to the vacuum vessel 101 via the bellows 140, the vertical movement can be performed as needed simultaneously with the rotation of the substrate platform 122 using the expansion / contraction function of the bellows 140. It has become.

  The substrate mounting unit 122 and the refrigerator 132 do not directly exchange heat via the refrigeration head 130. For example, the refrigerator 132 cools the cooling gas and stores it in the gap 121, and the gas When the substrate mounting part 122 is cooled in this way, it is necessary to introduce gas from the outside of the vacuum vessel 101. However, connection of these gas pipes (not shown) is performed via the magnetic fluid seal 142. Also good.

Further, although the refrigeration head 130 is disposed between the substrate platform 122 and the refrigerator 132, a configuration in which the refrigerator 132 is directly connected to the substrate platform 122 may be employed.
With respect to these configurations, it is possible to select a temperature distribution for cooling the substrate placed on the substrate placement unit and a configuration according to the purpose.

Next, the vibration isolator 180 (shown in FIG. 1) of the refrigerator disposed in the processing apparatus according to the present invention will be described with reference to FIG.
FIG. 2 shows a free piston type Stirling cycle-use refrigerator 200 already described with reference to FIG. 3 (reference numeral 132 in FIG. 1).
In addition, the same code | symbol is used about the same part of the structure of the refrigerator demonstrated in FIG.

  As described above, by connecting the piston 312 and the displacer 313 in the direction of the axis 314, the isothermal compression and isothermal expansion due to the pressure change of the working gas, and the heat absorption and exhaust heat due to the isovolume change at the time of the working gas flow, The reversible cycle which consists of this is performed, and the periphery of the heat absorption part 322 is cooled by this at low temperature.

  That is, as described above, the piston 312 held by the leaf spring 360 that is an elastic body is separate from the shaft 314 and the displacer 313 that are held by the leaf spring 350, and is provided so as to be movable in the arrow a direction. ing. Thereby, while the high-pressure working gas moves through the compression space 320 to the heat radiating part 321 to the regenerating part 323 to the heat absorbing part 322 to the expansion space 324, the heat absorption by the heat absorbing part 322 and the heat radiation by the heat radiating part 321 are performed ( Equal volume change) Stirling cycle is formed. And the heat absorption part 322 cools a to-be-cooled object (not shown) by absorbing heat from the to-be-cooled object (not shown). The refrigeration head 240 may be connected to the heat absorption part 322 to increase the contact area with the object to be cooled (not shown). Thus, the leaf spring 350 biases the elastic repulsion force in the direction opposite to the driving direction of the driving mechanism by the linear motor composed of the coil 310, the cylindrical permanent magnet 311 and the like, thereby displacer 313 in the direction of arrow a. And the reciprocating motion of the piston 312 is stabilized.

  However, the refrigerator 200 of the processing apparatus according to the present invention is further rotated directly around the shaft 314 by a rotating means (not shown) by being disposed immediately below the substrate platform 122. For this reason, in order to realize a smooth movement without lateral blurring in the radial direction with respect to the direction of the axis 314 of the piston 312 and the displacer 313 that affects the refrigerating capacity, the vibration isolation member 210 is attached to the peripheral portion of the leaf spring 350 that is an elastic body. (Shown in FIG. 2A). The shape of the elastic body 350 is preferably a disc shape. The elastic body may have a notch 211 around the rotation axis.

In addition, the weight distribution is evenly distributed with respect to the shaft 314 which is also the rotation shaft 220 (the rotation direction is indicated by reference numeral 230) of the refrigerator 200 so that the weight distribution is equal (45 degrees around the rotation shaft 220 in FIG. 2). However, it is not limited to the angle (interval) around the rotation shaft 220, and further, the weight is slightly different to adjust the balance of the entire rotating body including the refrigerator. Fine adjustment can also be performed using a vibration-proof member.
The anti-vibration member 210 is preferably made of a metal such as an alloy including iron having a weight and mechanical strength that effectively generates a force in the radial direction. The conventional method can be adopted.

FIG. 2B is a view of the lower part of the refrigerator 200 in the direction of the rotation shaft 220 as viewed from the arrow 250.
Anti-vibration members 210 are arranged at equal intervals on the peripheral edge of the leaf spring 350.
In this way, the vibration isolating member 210 that is evenly arranged at the peripheral edge of the leaf spring 350 increases the rigidity of the leaf spring 350 by rotating around the shaft 314 and receiving a centrifugal force in the radial direction, and also displaces the displacer. Since the natural frequency of 313 can be stably maintained, occurrence of lateral blur due to rotation of the refrigerator 200 can be prevented. In addition, it is possible to reduce the occurrence of positional deviation on the substrate mounting portion due to the rotation of the substrate and maintain a stable refrigerating capacity.

Substrate cooling experiments were conducted with the same structure as in FIG. 1 to which the present invention can be applied. FIG. 4 explains the whole.
In addition, about the same structure demonstrated in FIG. 1 shown by FIG. 4, it shows with the same code | symbol used in FIG.

Here, since the uniformity of the cooling effect of the substrate is also required for practical use, helium gas is once introduced into the space forming the gap 121 inside the substrate platform 122 and this helium gas is brought into contact with the refrigeration head 130. The cooling effect of the refrigerator 132 was confirmed by cooling the substrate mounting part 122 being cooled and bringing the cooled helium gas into contact with the entire back surface of the substrate W. Therefore, the substrate mounting portion 122 and the substrate W are sealed by a silicon rubber O-ring (not shown) so that the cooled helium gas efficiently contacts the substrate W.
The substrate pressing ring 120 is made of SUS, and the substrate mounting portion 122 is made of, for example, copper.

  Cooled helium gas introduction holes (not shown) were equally arranged at four positions of 90 degrees from the center of the substrate platform 122. Further, the exhaust holes (not shown) for the cooled helium gas were equally arranged at four positions of 90 degrees from the center of the substrate platform 122.

The temperature measurement of the substrate W and the substrate platform 122 will be described.
The thermocouple 405 was attached to the center of the substrate W, and the thermocouple 404 was attached to a location 90 mm away from the center of the substrate W using, for example, a ceramic adhesive. The thermocouples 404 and 405 are relayed by the connection component 402 and connected to the current collecting ring 134.
The current collecting ring 134 is connected to temperature display means (not shown).

  On the other hand, a platinum resistor element 403 is fixed to the substrate platform 122 and is also connected to a temperature display means (not shown) through the current collecting ring 134. Thereby, it is possible to measure the temperature whether the substrate W is fixed or rotating.

The distance between the gap 121 and the substrate W is about 0.5 mm. A Stirling cycle type refrigerator 132 is connected to the substrate platform 122, and the temperature of the substrate platform 122 is controlled to be −200 ± 2 ° C. The substrate W stands by at a position away from the substrate platform 122, and is placed on the substrate platform 122 by the substrate vertical drive mechanism (not shown) as the experiment starts, and is held by the substrate pressing ring 120.

The substrate pressing force was set to 19.6 N, for example, and helium gas was continuously supplied to the gap 121 between the substrate W and the substrate platform 122 by a gas flow rate controller (MFC) (not shown) at 5 sccm.
The cooling operation was performed while rotating the number of rotations of the substrate mounting portion at, for example, 59 rpm.

The radiator 131 can be suppressed to 60 ° C. or lower, the display value of the thermocouple 405 after 40 minutes from the holding of the substrate W is −184.2 ° C., and the display value of the thermocouple 404 is −186.3 ° C. It was confirmed that by suppressing the heat from 131, cooling is possible even when the substrate is rotated to a temperature range of 100K or less.
In addition, it was confirmed that the substrate W did not shift in position with the rotation of the substrate platform 122, and as a result, a good temperature distribution was measured.

As mentioned above, although preferred embodiment of this invention was described, this is an illustration for description of this invention,
It is not intended that the scope of the present invention be limited only to this embodiment.
For example, in the embodiment, the sputtering apparatus is taken as an example of a processing apparatus capable of reducing the pressure, but the present invention is also applicable to an etching apparatus by changing a target to which a potential is applied or changing a sputtering gas to an etching gas. Is possible.
Further, the present invention is not limited to a processing apparatus capable of depressurization, and may be applied to any processing apparatus having a substrate mounting portion having a holding means capable of mounting a substrate and a cooling means for cooling the substrate mounting portion. Is possible.
Therefore, the present invention can be implemented in various modes different from the above-described embodiments without departing from the gist thereof, and the present invention is effective even when the substrate size and the type of the substrate are different. It is clear that.

DESCRIPTION OF SYMBOLS 100 Sputtering apparatus 102 Cathode magnet 122 Substrate mounting part 132, 200, 300 Refrigerator 210 Vibration isolator 240, 330 Refrigeration head 312 Piston 313 Displacer 350, 360 Leaf spring

Claims (4)

A substrate placement unit capable of placing a substrate;
Holding means for holding the substrate on the substrate mounting portion;
A cooling means for cooling the substrate mounting portion;
A rotating means for rotating the substrate mounting portion and the cooling means on the same axis;
A processing apparatus comprising:
The cooling device has an elastic body on the same axis, and a vibration isolating member is disposed around a rotation axis of the elastic body.   The processing apparatus according to claim 1, wherein the elastic body has a disk shape, and a vibration isolating member is disposed at a peripheral edge thereof.   The processing apparatus according to claim 2, wherein the elastic body has a notch formed around the rotation axis. The processing apparatus according to claim 2, wherein the vibration isolation members are arranged at equal intervals.