JP2009212286A - Plasma treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment device which suppresses the ununiformity of temperature distribution near the outermost periphery of a test piece and is achieved in the reduction of a cost of a product. <P>SOLUTION: The plasma treatment device is provided with a sample stand 115 whose upper surface has a dielectric film 35 for electrostatic attraction and whose inside has the flow passage of a refrigerant which is formed therein, and plasma is formed above the sample stand to treat the test piece W disposed on the dielectric film 35. A first recess 31 and a second recess 34 through which heat transfer gas is supplied to the dielectric film 35 are formed while a first protrusion 31 and a second protrusion 33 are formed as electrostatic attraction surfaces. In this case, the flow rate of heat transfer gas which flows out along an arrow sign A is controlled by regulating a size L so as to permit the control of the temperature of a part protruded from the periphery of the sample stand 115 in the outer peripheral part of the test piece W independently from the temperature of a part except the outer peripheral part of the test piece W. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus for processing a sample using plasma, and more particularly, to a plasma processing apparatus of a type in which a sample is electrostatically adsorbed on a sample stage and a heat transfer gas is supplied to the back surface to control the temperature.

  Generally, a plasma processing apparatus used for manufacturing a semiconductor device electrostatically adsorbs a vacuum vessel, a gas supply system connected to the vacuum container, an exhaust system that maintains the processing chamber pressure at a predetermined value, and a wafer as a sample. It is composed of a sample stage to be fixed, an antenna for generating plasma in a vacuum vessel, etc., a mixed gas is supplied into the vacuum vessel, it is turned into plasma by discharge, and a wafer placed on the sample stand by various active species generated thereby This sample is etched.

  By the way, in the case of this plasma processing apparatus, it is necessary to control various parameters in order to ensure a desired etching performance. One of the parameters at this time is the wafer temperature. A high voltage is applied to the sample wafer, and the sample wafer is electrostatically adsorbed to the dielectric film on the sample table. Then, for example, helium gas is supplied from the inside of the sample table to the back surface of the sample, and the sample is placed between the sample table and Conventionally, a method has been employed in which heat transfer gas is interposed to improve heat transfer properties, thereby maintaining the sample temperature at a desired value and adjusting the temperature distribution to a desired state.

At this time, the back surface of the sample is further divided into a central region and an outer peripheral region, and a desired temperature distribution can be formed on the sample surface by supplying a heat transfer gas having a different pressure for each region. Various techniques have been conventionally known.
For example, in one proposal, a plurality of refrigerant paths are provided in the sample stage, and a temperature gradient is given to the sample stage by flowing a refrigerant having a predetermined different temperature to each of them, and this is applied to the sample via the heat transfer gas. The technique of giving is disclosed (for example, refer to Patent Document 1).

In another proposal, a technique is disclosed in which heat transfer is controlled by dividing the area filled with the heat transfer gas into a large number and independently controlling the pressure in each area (see, for example, Patent Document 2). .
JP 2004-259829 A Japanese Patent Laid-Open No. 10-41378

In the above prior art, it cannot be said that the temperature control in the peripheral portion of the sample is considered, and there is a problem in improving the manufacturing yield.
That is, in the case of such a plasma processing apparatus, the outermost peripheral end portion of the sample protrudes outward from the mounting portion of the sample stage and is fixed. Since the cooling effect by the heat transfer gas does not work sufficiently, the temperature rises locally.

  Therefore, in the case of the prior art, there will be a region where it is difficult to adjust the temperature in the outermost peripheral portion of the sample, and in this region, a result equivalent to the processing on the center side cannot be obtained. As a result, a decrease in the manufacturing yield that the number of devices per unit sample is reduced is unavoidable, resulting in a problem that the manufacturing cost increases.

  The present invention has been made in view of the points that are not taken into consideration in the above-described conventional technique, and the object thereof is to suppress uneven temperature distribution in the vicinity of the outermost periphery of the sample, and to reduce the product cost. Another object of the present invention is to provide a plasma processing apparatus.

  The purpose is to place a sample stage in the processing chamber, which is provided with a dielectric film for electrostatic adsorption on the upper surface and in which a refrigerant flow path is formed, and to form plasma above the sample stage in the processing chamber In the plasma processing apparatus for processing the sample placed on the dielectric film, when the sample is placed on the dielectric film, the sample protrudes from the periphery of the sample stage at the outer periphery of the sample. This is achieved by providing sample temperature control means for controlling the temperature of the portion independently of the temperature of the portion other than the outer peripheral portion of the sample.

  At this time, the sample temperature control means is formed on the dielectric film such that when the sample is placed on the dielectric film, a circular area is defined in the center of the back surface of the sample. 1 dent and a second dent formed in the dielectric film such that when the sample is placed on the dielectric film, an annular area is defined on the outer peripheral side of the circular area. And when the sample is placed on the dielectric film, the sample is positioned between the first and second recesses, and abuts against the back surface of the sample to form the first and second recesses. A first annular convex portion formed on the dielectric film so as to seal the gap, and when the sample is placed on the dielectric film, the first convex portion on the outer peripheral side of the second concave portion. A heat transfer gas is supplied to the second annular convex portion partitioning between the second concave portion and the processing chamber, and the first concave portion. A first conduit, can achieve the above object so as to be composed of a second conduit for supplying the heat transfer gas into the second recess.

  In this case, the distance from the outer peripheral end of the first convex portion to the outer peripheral end of the second convex portion may be 8 times or less the thickness of the sample, and the second concave portion The flow rate of the heat transfer gas supplied to the first recess may be greater than the flow rate of the heat transfer gas supplied to the first recess, and further, the second conduit may be You may make it be the several pipe line arrange | positioned by the substantially equal space | interval in the circumferential direction of 2 dent parts.

  Further, at this time, the sample temperature control means is formed on the dielectric film so that when the sample is placed on the dielectric film, a circular region is defined in the center of the back surface of the sample. When the sample is placed on the dielectric film, the first conduit for supplying a heat transfer gas to the recess, and the dielectric film, the outer periphery of the sample, from the periphery of the sample stage The above-described object can be achieved even if it is constituted by the second pipe that supplies the heat transfer gas directly to the protruding portion.

  In this case, the second duct may pass through the focus ring for protecting the dielectric film, and further, the second duct may be connected to the focus ring for protecting the dielectric film. You may make it the heat insulating material be provided in the part which has passed through.

  According to the present invention, since the local temperature distribution non-uniformity at the outermost periphery of the sample can be suppressed, the outermost peripheral portion of the sample can also be used for manufacturing a semiconductor device. Can be reduced.

Hereinafter, a plasma processing apparatus according to the present invention will be described in detail with reference to embodiments shown in the drawings.
FIG. 1 shows an embodiment of the present invention. Here, the plasma processing apparatus according to this embodiment is roughly divided into a processing section mainly composed of an upper vacuum vessel 11 and a lower bed section 119. Sometimes the vacuum vessel 11 is supported on the top of the bed portion 119 by the legs 118.
First, an electromagnetic wave generator mainly composed of a magnetron 13 for generating an electromagnetic field in the vacuum vessel 11 is provided above the processing unit, and below the vacuum vessel 11 is evacuated to evacuate and depressurize the inside of the vacuum vessel 11. A device 121 is provided.

In addition, a processing chamber 19 is provided inside the vacuum vessel 11, and a sample stage 115 is provided in the processing chamber 19, and a sample W such as a semiconductor wafer that is a non-processed product is placed on the sample stage 115. Stage 110 is provided.
On the other hand, the lower bed portion 119 is supplied with high frequency power to a heat exchanger 121 that controls the temperature distribution inside the sample table 115 and an electrode composed of a conductive member disposed in the sample table 115. A high-frequency power source 123 for forming a bias potential on the upper surface of the sample and a DC power source 124 for supplying power for electrostatically attracting the sample W to the stage 110 are provided.

Further, a gas supply unit 125 is provided between the sample W and the stage 110 to supply a heat conduction gas that functions to increase the heat transfer efficiency between the sample W and the sample stage 115 and to adjust the flow rate thereof.
Here, the gas supply unit 125 supplies not only the heat conduction gas mentioned here but also the processing gas.
At this time, the bed portion 119 is formed in a substantially rectangular parallelepiped shape, so that a space for storing the above-described specific device is obtained. At this time, the flat upper surface is formed by the operator. It functions as a stepping board that can be mounted, and can be used by an operator when working with devices inside and outside the vacuum vessel 11, for example.

A processing chamber 19 is formed inside the vacuum vessel 11, and a shower plate 18, which is a substantially circular plate having a diameter larger than the diameter of the sample W, forms the ceiling surface of the processing chamber 19 above the processing chamber 19. It is arranged like that.
At this time, the shower plate 18 is provided with a plurality of through holes arranged uniformly around the sample stage 115 or a point substantially coaxial with the center of the sample W placed thereon, The processing gas supplied from the unit c to the upper surface of the shower plate 18 flows into the ceiling portion of the processing chamber 19 through the above-described through hole.

Above the shower plate 18, a substantially disk-shaped window member 15 made of a dielectric material such as quartz is disposed at a predetermined interval, and a microwave antenna 16 is further provided above the window member 15. ing.
Therefore, the microwave radiated from the antenna 16 is introduced into the space between the sample stage 115 in the processing chamber 19 and the shower plate 18 thereabove through the window member 15 and the shower plate 18, and the processing gas is supplied. Used to turn into plasma.
At this time, the upper part of the window member 15 of the vacuum vessel 11 is formed as a substantially cylindrical space, and has a shape in which the microwave introduced therein is easily amplified.

In the vacuum vessel 11, the lower part of the sample stage 115 is a space into which plasma and reactive gas inside the processing chamber 19 above the sample stage 115 and particles of reaction products formed by the plasma treatment flow. Is forming.
Therefore, an opening 120 communicating with the evacuation apparatus 121 is provided on the bottom surface of the vacuum vessel 11, whereby particles and the like flowing into the lower part of the sample stage 115 are discharged from the opening 120 to the outside of the processing chamber 19. ing.
At this time, a plurality of rotatable plate-shaped flap valves are disposed in the passage between the opening 120 and the vacuum exhaust device 121, and the sectional area of the passage is adjusted by rotating the flap valve. The amount of exhaust in the processing chamber 19 can be adjusted.

A magnetron 13 is disposed above the inside of the vacuum vessel 11, and the microwave generated by the magnetron 13 propagates in a substantially horizontal direction through a waveguide 12 having a substantially rectangular cross section and then travels downward. Instead, it is introduced from the antenna 16 into the amplification space above the window member 15. A microwave having a predetermined frequency amplified in this space is supplied into the lower processing chamber 19 through the window member 15 and the shower plate 18.
Further, the processing gas supplied from the gas supply unit 125 is supplied to the space between the window member 15 and the shower plate 18 through the processing gas introduction port, and spreads to fill the entire space. Is supplied from the through hole toward the sample stage 115 in the processing chamber 19 below the through hole.

At this time, although not shown, various sensors are provided to adjust the operation of each unit described above, and signals from these sensors are received via communication means, and the state of each unit is detected from the received signal. Then, based on the result, a control device CTRL is provided that transmits a signal for instructing the operation of each of these units via the communication means, and adjusts these operations.
Also, although not shown in the figure, an equipment named B room is adjacent to the vacuum container 11 as a place where the sample W is preliminarily transported before being carried into the processing chamber 19 in the vacuum container 11. Is provided.

The B chamber and the vacuum vessel 11 communicate with each other via a gate 111, and the gate 111 is opened and closed by a gate valve 116 and a cylinder 117.
Therefore, when the sample W is transferred to the B chamber, the gate 111 is opened by the gate valve 116, and the robot arm 112 transfers the sample W from the B chamber to the upper side of the sample stage 115.
When the transfer is completed, the robot arm 112 is housed in the room B, the gate 111 is closed by the gate valve 116, and then the inside of the vacuum container 11 is decompressed by the vacuum exhaust device 121.

The sample W transported on the sample stage 115 is attracted and held on the sample mounting surface by the force of the electrostatic field generated according to the electric power supplied from the DC power supply 124, and thereafter processed in the processing chamber 19. A working gas is supplied.
At this time, a solenoid coil 14 is provided on the upper portion of the vacuum vessel 11, and a magnetic field is formed in the processing chamber 19. Therefore, when a microwave is supplied here, the processing gas is excited by the interaction between the microwave and the magnetic field, and plasma is generated.
Therefore, at least one layer to be processed formed on the surface of the sample W is etched using this plasma.

At this time, high frequency power is supplied from the high frequency power source 123 to the electrode of the sample stage 115, thereby forming a predetermined bias potential above the sample W. Therefore, charged particles in the plasma are attracted to the surface of the sample W in accordance with the difference between the bias potential and the plasma potential, and an anisotropic etching process is promoted.
Particles such as plasma, processing gas, and products pass through a passage between the inner wall of the processing chamber 19 in the vacuum vessel 11 and the side wall surface of the processing table, move to a space below the processing table, and are evacuated. The apparatus 121 is discharged from the opening 120 to the outside of the processing chamber 19 by the operation of the apparatus 121.
Here, during the processing, the supply of the processing gas by the gas supply unit 125 and the discharge from the opening 120 by the vacuum exhaust device 121 are adjusted, and as a result, both are balanced and the inside of the processing chamber 19 is kept at a predetermined pressure. Will be adjusted. At this time, the side wall surface and the bottom surface of the vacuum vessel 11 are grounded.

  At this time, the opening 120 is formed in a substantially circular shape, and is disposed substantially concentrically with the central axis of the substantially cylindrical sample stage 115. Therefore, according to this embodiment, the processing chamber 19, the window member 15, the shower plate 18, the sample stage 115, the opening 120, and the vacuum pump in the vacuum evacuation device 121 are arranged around substantially the same axis. As a result, the uniformity of the processing is improved about the axis and the circumferential direction of the sample W, and the processing yield is improved.

When the etching process is completed, the DC power supply 124 is turned off, and the sample W and the sample stage 115 are neutralized. Thereafter, the high frequency power supply 123 is turned off, the supply of the processing gas is stopped, and the magnetron 13 stops the emission of the microwave.
As a result, the plasma loses the energy supply source and the gas supply source and disappears, and the remaining gas is exhausted by the vacuum exhaust device 121. Thereafter, the exhaust is stopped and air is supplied from the gas supply unit 125. As a result, the inside of the vacuum vessel 11 is ventilated. Thereafter, the gate valve 116 opens the gate 111, the robot arm 112 in the B chamber carries the sample W from the sample stage 115 into the B chamber, the gate valve 116 closes the gate 111, and the entire etching process is completed.

The sample stage 115 is provided with two gas introduction pipes 113 and 114. At this time, one of the gas introduction pipes 113 is formed as a first pipe line in a state of penetrating up and down substantially at the center of the sample stage 115. The other gas introduction pipe 114 is formed in a state of penetrating vertically around the periphery of the sample stage 115 as a second pipe line.
During the etching process, the gas introduction pipe 113 is supplied with heat transfer gas from the unit b of the gas supply unit 125 as a refrigerant, and the gas introduction pipe 114 is supplied with heat transfer gas from the unit a of the gas supply unit 125 as refrigerant. Is supplied.

  Here, FIG. 2 shows details of the unit a and the unit b of the gas supply unit 125. First, the unit a will be described. First, the pressure in the gas introduction pipe 113 is measured by the pressure gauge 21, and the pressure gauge 21 A command is given to the MFC 25 to adjust the flow rate based on this signal, and thereby the flow rate is controlled so that the pressure in the gas introduction pipe 113 becomes a predetermined value. As a result, the pressure in the gas introduction pipe 113 is predetermined. The value is kept almost constant. At this time, the valve 23 is opened during the etching process, and is closed otherwise.

Next, the unit b will be described. In this case, the pressure in the gas introduction pipe 114 is measured by the pressure gauge 22, and the valve 24 is opened if the pressure is lower than a predetermined value based on the signal from the pressure gauge 22. Gas is supplied and the valve 27 is closed. The flow rate at this time is controlled by the MFC 26 based on a signal from the pressure gauge 22.
On the other hand, when the pressure in the gas introduction pipe 114 is higher than a predetermined value, the valve 24 is closed, the valve 27 is opened, the vacuum pump 28 is exhausted, and the pressure is reduced. Here, when the etching process is not performed, both the valves 24 and 27 are closed.
In this embodiment, an MFC (mass flow controller) is used for flow rate control, but it may be replaced with PCV.

Next, details of the stage 110 on which the sample W is placed will be described.
FIG. 3 is an enlarged cross-sectional view of the outer peripheral edge of the upper part of the sample stage 115. In this figure, the upper surface of the sample stage 115 is covered with a dielectric film 35 serving as a medium of electrostatic attraction force. In this portion, when the sample W is placed, the range where the back surface of the sample W is in contact is defined as the stage 110.
At the center of the stage 110, there is a gas introduction pipe 113 for supplying a heat transfer gas between the sample W and the stage 110, and a heat transfer gas is also supplied between the sample W and the stage 110 on the outer periphery of the stage 110. There is a gas introduction pipe 114 to be used.
A focus ring 36 for protecting the dielectric film 35 from plasma is provided on the outer periphery side of the stage 110 above the sample stage 115.

At this time, the upper surface of the dielectric film 35 is not a plane, but is formed with a circular recess 31 and an annular recess 34 as well as annular protrusions 32 and 33 as viewed from above.
At this time, as shown in FIG. 4, the recess 31 is located at the center of the sample stage 115, and the annular recess 34 and the annular protrusions 32, 33 are formed concentrically around the recess 31. Here, the gas introduction tube 113 is opened to the recess 31 and the gas introduction tube 114 is opened to the recess 34. Therefore, the recesses 31 and 34 become introduction portions of the heat transfer gas. And the convex parts 32 and 33 become the electrostatic adsorption surface of the sample W by the sample stand 115, and the convex part 32 forms an inner adsorption surface here, and the convex part 33 forms an outer adsorption surface.
Therefore, hereinafter, the inner suction surface is also referred to as the inner suction surface 32, and the outer suction surface is also referred to as the outer suction surface 33.

Here, first, the inner adsorption surface 32 functions to suppress the heat transfer gas introduced into the recess 31 from the gas introduction pipe 113 from flowing out to the outside by electrostatic adsorption.
Next, the outer adsorption surface 33 also functions to suppress the heat transfer gas introduced into the recess 34 from the gas introduction pipe 114 from flowing out to the outside by electrostatic adsorption. An appropriate amount of heat transfer gas leaks from the outer adsorption surface 33. Then, as shown by an arrow A in FIG. 3, the leaked heat transfer gas flows from the back surface of the peripheral portion of the sample W along the outer peripheral end surface of the sample W, whereby the temperature of the peripheral portion of the sample W is increased. The sample W can be adjusted independently of the other parts.

That is, in this case, sample temperature control means is provided for controlling the temperature of the portion of the outer periphery of the sample W that protrudes from the periphery of the sample stage 115 independently from the temperature of the portion other than the outer periphery of the sample W. This is a feature of this embodiment.
Here, a difference is set between the degree of suppression of the heat transfer gas flow out by the inner adsorption surface 32 and the degree of heat transfer gas outflow suppression by the outer adsorption surface 33. This will be specifically described.

During the etching process, a heat transfer gas is supplied into the recess 34 and the balance between the outflow and inflow of the gas is adjusted by the gas supply unit 125 so that the average pressure in the recess 34 is maintained constant. .
At this time, first, the width of the inner adsorption surface 32 is such that the pressure distribution due to the outflow of the heat transfer gas from the introduction portion of the inner peripheral heat transfer gas by the recess 31 or the inflow of the heat transfer gas from other than the gas introduction pipe 114. The disturbance is made sufficiently large so that it does not affect the temperature distribution width in the circumferential direction on the surface of the sample W.

  Therefore, as shown in the figure, if the width of the outer adsorption surface 33 is made smaller than the width of the inner adsorption surface 32, the gas sealing property by the outer adsorption surface 33 becomes weaker than that of the inner adsorption surface 32. The heat transfer gas outflow (directional outflow) indicated by the arrow A appears, and as a result, a temperature gradient is given to the portion of the back surface where the gas contacts the sample W, and the temperature distribution width of the surface of the sample W above it increases. Here, the increase in the temperature distribution width at this time can be suppressed by narrowing the width L of the gas contact surface with respect to the sample W, that is, the sum L of the width of the recessed portion 34 and the width of the outer adsorption surface 33.

Here, FIG. 5 shows the temperature distribution characteristic by the sum L at this time, and M on the vertical axis indicates that the sample W is in contact with the outer peripheral end of the outer suction surface 33 from the inner peripheral end of the recessed portion 34. The ratio of the temperature distribution width between the front surface and the back surface of the portion, that is, the portion represented by L of the sample W, that is, the sample surface temperature distribution width / the sample back surface temperature distribution width is represented. At this time, the thickness of the sample W is 0.5 mm.
Therefore, if the sum L is made relatively small with respect to the thickness of the sample W, an increase in the temperature distribution width due to the anisotropic outflow of gas can be sufficiently suppressed due to the effect of thermal diffusion. It is understood that the portion protruding from the periphery of 115 is sufficiently limited, and only the temperature can be controlled independently of the temperature of the portion other than the outer peripheral portion of the sample W. In practice, the sum L is the thickness of the sample W. It can be seen that it should be suppressed to 8 times or less.

  At this time, from the viewpoint of cooling as much as possible to the outermost peripheral side of the sample W as much as possible, the width of the outer suction surface 33 should be narrow, but if it is too narrow, the outer suction surface becomes difficult due to processing accuracy. 33, the gas tightness of the gas flow control unit is too low, the average pressure in the recess 34 cannot reach the predetermined pressure even at the maximum flow rate of the gas flow rate control unit, or the performance of the vacuum evacuation device 121 is a problem. The amount of gas flowing into the chamber 19 may exceed the amount exhausted by the vacuum evacuation device 121, and the inside of the processing chamber 19 may be pressurized. Therefore, the width of the outer suction surface 33 is such that such a problem does not occur. It is desirable to narrow.

Next, FIG. 6 is a diagram showing a comparison between the case of the above embodiment and the case of the prior art.
Here, the upper characteristic (a) shows the temperature distribution on the sample surface, where the vertical axis is the temperature and the horizontal axis is the position of the sample surface with the center as the origin.
The lower characteristic (b) shows the CD (Critical-Dimension) shift amount distribution on the sample surface, where the vertical axis is the CD shift amount, and the horizontal axis is the center. The sample surface position.
In the upper characteristic (a) and the lower characteristic (b), the solid line is the characteristic according to the above embodiment, and the broken line is the characteristic according to the prior art. Therefore, from these figures, according to the embodiment of the present invention, It can be seen that the outer peripheral side of the sample can be cooled more than the prior art, and the region where the CD shift amount is narrowed can be brought closer to the outer peripheral side, so that the EE can be narrowed.

Next, another embodiment of the present invention will be described with reference to FIG.
Here, the embodiment of FIG. 7 differs from the embodiment described in FIG. 3 in that the heat transfer gas introduction pipe is moved from the inside of the sample stage 115 to the outer periphery, and the stage 110 is placed above the sample stage 115. A gas introduction pipe 71 is provided through a focus ring 36 provided on the outer peripheral side, whereby the heat conduction gas is blown out from directly below a portion protruding from the stage 110 at the outermost peripheral portion of the sample W. As a result, the recess 34 and the gas introduction pipe 114 in the embodiment of FIG. 3 are removed, and the heat introduction gas is supplied to the gas introduction pipe 71 from the unit a of the gas supply unit 125 shown in FIG. Become.

Therefore, in the embodiment of FIG. 7, the heat conduction gas is sprayed directly on the outermost periphery of the sample W, thereby cooling the outermost periphery of the sample W. At this time, the focus ring 36 is During the etching process, it is heated by heat input from plasma.
Therefore, in this embodiment, a heat insulating material 72 is applied to a portion where the gas introduction pipe 71 passes through the focus ring 36, and this portion is covered with the heat insulating material 72, so that the heat of the focus ring 36 is not transmitted to the heat conduction gas. I am doing so.
At this time, the temperature of the gas blown out from the gas introduction pipe 71 also depends on the temperature in the sample stage 115. Accordingly, the temperature of the sample stage 115 is controlled by the heat exchange device 122, and the temperature of the outermost peripheral portion of the sample W is adjusted by controlling the flow rate of the heat conduction gas by the unit a of the gas supply unit 125.

Also in the embodiment of FIG. 7, arranging a plurality of gas introduction pipes 71 at equal intervals leads to saving of the total flow rate of the heat conduction gas.
In the embodiment of FIG. 7 as well, by adjusting the width of the portion to which the heat conduction gas is sprayed at the outermost peripheral portion of the sample W, the spread of the temperature distribution width at the outermost peripheral portion can be controlled. If the obtained width is 8 times or less the thickness of the sample W, it can be sufficiently suppressed.

It is sectional drawing which shows one Embodiment of the plasma processing apparatus which concerns on this invention. It is explanatory drawing which shows the supply means of the heat transfer gas in one Embodiment of the plasma processing apparatus which concerns on this invention. It is detailed explanatory drawing of the sample stand in one Embodiment of this invention. It is an enlarged view of the sample stand in one Embodiment of this invention. It is a temperature distribution characteristic view by the sum L of the width | variety of the gas contact surface with respect to the sample in one Embodiment of this invention. It is the characteristic view which showed the temperature distribution and CD shift amount distribution of the sample outermost periphery by one Embodiment of this invention compared with the prior art. It is detailed explanatory drawing of the sample stand in other one Embodiment of this invention.

Explanation of symbols

11: Vacuum container 12: Waveguide 13: Magnetron 14: Solenoid coil 15: Window member 16: Antenna 17: Processing gas inlet 18: Shower plate 19: Processing chamber 21: Pressure gauge 22: Pressure gauge 23: Valve 24: Valve 25: MFC
26: MFC
27: Valve 28: Vacuum pump 31: Recess 32: Convex (inner suction surface)
33: Convex part (outer suction surface)
34: Depression 35: Dielectric film 36: Focus ring 71: Gas introduction pipe 72: Heat insulating material 110: Stage 111: Gate 112: Robot arm 113: Gas introduction pipe 114: Gas introduction pipe 115: Sample stage 116: Gate valve 117: Cylinder 118: Leg 119: Bed part 120: Opening 121: Vacuum exhaust device 122: Heat exchange device 123: High frequency power supply 124: DC power supply 125: Gas supply unit

Claims (8)

A sample stage having a dielectric film for electrostatic adsorption provided on the upper surface and having a coolant flow passage formed therein is disposed in the processing chamber, and plasma is formed above the sample stage in the processing chamber to form the dielectric. In a plasma processing apparatus for processing a sample placed on a body membrane,
When the sample is placed on the dielectric film, the temperature of the outer peripheral portion of the sample that protrudes from the peripheral portion of the sample stage is controlled independently of the temperature of the portion other than the outer peripheral portion of the sample. A plasma processing apparatus, characterized in that a sample temperature control means is provided. The plasma processing apparatus according to claim 1,
The sample temperature control means comprises:
When the sample is placed on the dielectric film, a first recess formed in the dielectric film so that a circular region is defined in the center of the back surface of the sample;
When the sample is placed on the dielectric film, a second recess formed in the dielectric film so that an annular region is defined on the outer peripheral side of the circular region;
When the sample is placed on the dielectric film, the sample is positioned between the first and second recesses, and is in contact with the back surface of the sample between the first and second recesses. A first annular protrusion formed on the dielectric film so as to seal;
When the sample is placed on the dielectric film, a second annular convex portion that partitions the second concave portion and the processing chamber on the outer peripheral side of the second concave portion;
A first conduit for supplying a heat transfer gas to the first recess;
A plasma processing apparatus comprising: a second pipe for supplying a heat transfer gas to the second recess. The plasma processing apparatus according to claim 2,
The plasma processing apparatus, wherein a distance between an outer peripheral end of the first convex portion and an outer peripheral end of the second convex portion is not more than eight times the thickness of the sample. The plasma processing apparatus according to claim 1,
The plasma processing apparatus, wherein the flow rate of the heat transfer gas supplied to the second recess is greater than the flow rate of the heat transfer gas supplied to the first recess. The plasma processing apparatus according to claim 1,
The plasma processing apparatus, wherein the second pipeline is a plurality of pipelines arranged at substantially equal intervals in the circumferential direction of the second recess. The plasma processing apparatus according to claim 1,
The sample temperature control means comprises:
When the sample is placed on the dielectric film, a recess formed in the dielectric film so that a circular region is defined at the center of the back surface of the sample,
A first pipe for supplying a heat transfer gas to the recess;
When the sample is placed on the dielectric film, the outer peripheral portion of the sample is configured with a second pipe that supplies heat transfer gas directly to a portion protruding from the peripheral portion of the sample stage. A plasma processing apparatus. The plasma processing apparatus according to claim 6,
The plasma processing apparatus, wherein the second pipe passage passes through the focus ring for protecting the dielectric film. The plasma processing apparatus according to claim 7,
A plasma processing apparatus, wherein a heat insulating material is provided in a portion where the second conduit passes through the focus ring for protecting the dielectric film.

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