JP2008214723A - Plasma treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment device where the generation of foreign matter is suppressed, and the yield of treatment is improved. <P>SOLUTION: The plasma treatment device comprises: a vacuum vessel; and an exhaust apparatus arranged at the lower part of a treatment chamber in the vacuum chamber and exhausting the inside of the treatment chamber, so as to decompress, wherein, a wafer arranged in the treatment chamber is treated using plasma generated in the treatment chamber. The device comprises: a plurality of sheet members arranged at the inside of an opening making the exhaust apparatus communicate with the treatment chamber, and rotating around a prescribed axis; and a plurality of disks fitted to both the edges of each sheet member and arranged with a fine gap with the inner side wall of the opening, and is provided with a controller controlling the above exhaust by the rotation of the sheet members. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vacuum processing apparatus for processing a substrate-like sample such as a semiconductor wafer while introducing a processing gas into a decompressed processing chamber inside a vacuum vessel.

  2. Description of the Related Art In a vacuum processing apparatus for manufacturing a semiconductor device by processing a substrate-like sample such as a semiconductor wafer, a processing gas is introduced into a processing chamber disposed inside a vacuum vessel and depressurized to a predetermined degree of vacuum. A desired shape is formed on the surface. For example, a highly reactive gas introduced into the processing chamber is turned into plasma by supplying an electric field from the outside of the vacuum vessel, and is physically and chemically reacted with charged particles such as ions and reactive particles such as radicals in the plasma. A thin film previously formed on the wafer surface is processed into a desired shape.

  In such a vacuum processing apparatus, an exhaust path through which process gas, particles in plasma and reaction product particles flow and exhaust is provided, and the inside of the vacuum vessel is depressurized to a predetermined degree of vacuum to maintain a constant value. It has been demanded. In order to satisfy such a requirement, it is necessary to adjust the displacement. For example, what was described in patent document 1 is known.

  The vacuum exhaust means includes an exhaust valve provided with a plurality of rotating shutters and an exhaust pump below the exhaust valve, and the exhaust valve is disposed directly below the sample stage. Each of the plurality of plate-shaped shutters is arranged approximately horizontally (in the wafer surface direction), and the shutter rotates around an axis attached to each of the shutters so that the area communicates between the opening of the inner chamber and the exhaust pump. Adjust. When these shafts are rotated, the plates of each shutter come into contact with each other to seal and close the opening. Further, the area that communicates when the shutter plates are substantially parallel to the sample stage direction (upward direction) is the largest. The exhaust valve is provided with driving means such as a motor for adjusting the rotation of the shutter, and the exhaust means adjusts the amount and speed of the exhaust by adjusting the opening area of the shutter and the driving of the exhaust pump. .

In such a case, it is required to realize the amount of exhaust from the vacuum vessel or the internal pressure set by the user by setting the shutters to have the desired mutual interval and angle. In particular, when it is desired to maintain the inside of the vacuum vessel at a relatively high pressure, the surfaces of the shutters are made substantially horizontal so that the amount of exhaust is as small as possible. The area of the opening is remarkably reduced, so that the opening is substantially sealed. Therefore, the gap between the plates of the shutters or the inner wall of the exhaust valve body surrounding them is suppressed to a minimum size that does not contact.
JP 2006-287053 A

  In the above prior art, the problem that reaction product deposits (depots) grow on the exhaust valves and the plates of the shutters has not been sufficiently considered. Furthermore, since the gap is narrow, the deposit developed on the inner wall of the exhaust valve main body and each shutter plate are scraped to become a source of new deposit.

  An object of the present invention is to provide a plasma processing apparatus that suppresses the generation of foreign matter and improves the process yield.

  The plasma processing apparatus of the present invention includes a vacuum vessel and an exhaust device that is disposed below the processing chamber in the vacuum vessel and exhausts the pressure in the processing chamber to depressurize the wafer. Processed using plasma generated in a room, disposed inside an opening communicating with the exhaust device and the processing chamber, attached to both ends of a plurality of plate members and plate members that rotate about a predetermined axis, It has a plurality of discs arranged with a minute gap from the inner wall of the opening, and is equipped with a regulator for adjusting the exhaust by rotation of the plate member.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a cross-sectional view schematically showing the configuration of the plasma processing apparatus according to the first embodiment of the present invention. In this figure, the processing chamber 100 is connected to a vacuum transfer container 144 and communicated or blocked between them by an open / close atmospheric gate valve 114 disposed therebetween. With the atmospheric gate valve 114 opened, the space inside the vacuum transfer container 144 and the space inside the processing chamber 100 communicate with each other and the pressures of both are substantially equal. When the atmospheric gate valve 114 is opened, a wafer, which is a sample, is transferred from the inside of the vacuum transfer container 144 onto the sample stage 104 placed in the internal processing chamber and placed thereon.

  In this embodiment, after the sample is detected and confirmed that the sample is placed on the sample stage 104, the atmospheric gate valve 114 is closed to block the inside of the processing chamber 100 and the inside of the vacuum transfer container 144, and the processing chamber The inside of 100 is sealed and processing is started.

  As shown in FIG. 1, a discharge chamber portion is disposed in the upper portion of the processing chamber 100, and the discharge chamber portion is disposed inside the lid member 142 constituting the lid of the vacuum vessel and the lid member 142. A structure including an antenna member, a magnetic field generator having a coil 127 disposed on the side and above the antenna member and surrounding the discharge chamber, and a ceiling member disposed below the antenna member Has been. In addition, a radio wave source unit 125 that supplies radio waves in the UHF band and VHF band emitted from the antenna member is disposed above the magnetic field generation unit. The antenna member is disposed between the antenna 126 and the lid member 142 so as to insulate between the flat antenna 126 disposed inside the lid member 142 made of a conductive member such as SUS. It has at least one dielectric 128 having a ring shape arranged to conduct radio waves emitted from the antenna 126 to the lower ceiling member side.

  Further, the ceiling member has a quartz plate 103 made of a dielectric material such as quartz to conduct the transmitted radio wave to the lower processing chamber side, and a processing plate disposed below the quartz plate and supplied. It has a shower plate 134 in which a plurality of holes for dispersing and introducing the process gas inside the processing chamber are formed.

  The space formed below the shower plate 134 and above the sample stage 104 is due to the interaction between the radio wave introduced into the supplied process gas through the quartz plate 103 and the magnetic field supplied from the magnetic field generator. The discharge chamber 132 is a space where plasma is formed. Further, a space is formed between the quartz plate 103 and the shower plate 134 with a minute gap, and the process gas to be supplied to the discharge chamber 132 is first supplied to the space and passes through the shower plate 134. The lever space and the discharge chamber 132 communicate with each other and flow into the discharge chamber 132 through the hole through which the process gas flows. The space is a buffer chamber 129 provided so that the process gas is dispersed from the plurality of holes and flows into the discharge chamber 132. This process gas is supplied from a controller 143 that regulates the supply of a fluid such as a gas via the process gas line 101 and the process gas shutoff valve 102.

  One or more chambers are arranged inside the outer chambers 111 and 112 that constitute the outer wall of the vacuum chamber portion of the processing chamber 100 and are arranged one above the other, and one is a multiple chamber arranged inside the other. ing. In this embodiment, there are two chambers inside and outside. That is, the inner chamber 109 is provided inside the upper outer chamber 111, and the inner chamber 110 is provided inside the lower outer chamber 112. That is, two upper and lower inner chambers 109 and 110 are provided. The sample stage 104 is disposed inside the inner chambers 109 and 110, and the inside of the innermost chamber constitutes a vacuum chamber 132 'in which plasma is formed and gas and reaction products flow and are exhausted.

  The vacuum chamber 132 ′ communicates with the upper discharge chamber 132, and is depressurized by an evacuation means configured to be able to communicate with the space between the inner chamber 109 and the outer chamber 111, as will be described below. The plasma, gas, and reaction product in the discharge chamber 132 are arranged so that they can move during processing.

  In order for the sample to be processed to be placed on the sample stage 104 in the inner chambers 109 and 110, a gate capable of transferring the wafer to the inner chamber 109 or 110 is required. Further, a valve that opens and closes and seals the gate to shut off and communicate the space inside and outside the chamber is required.

  In the first embodiment, the gate provided between the inner side of the processing chamber 100 and the inner side of the vacuum transfer container 144 is opened or closed to be sealed so as to communicate and block both, and the atmospheric gate valve 114 and the inner chamber 109. A process gate valve 113 is provided which opens and closes the inside and the outside of the cylinder and seals the two by communicating with each other. The atmospheric gate valve 114 is disposed on the inner side wall of the vacuum transfer container 144 and is configured to be movable in the vertical and horizontal directions by the driving means 122. The atmospheric gate valve 114 is closed or opened so as to seal the gate on the inner side wall. To do. In addition, a gate is provided in a position where the vacuum transfer container 144 and the processing chamber 100 are connected to the outer chamber 111 constituting the vacuum container so as to communicate with the gate on the vacuum transfer container 144 side.

  A lower inner chamber 110 is disposed below the block of the sample stage 104, and an opening is disposed in a central portion of the inner chamber 110. This opening communicates with an evacuation means having an exhaust valve 107 and an exhaust pump 108 disposed below the inner stage 110 and below the sample stage 104, and inside the inner chamber 109 flowing around the sample stage 104. This is where the gas flows. That is, the space between the support beams 120 around the sample stage 104 and the space in the inner chamber 110 below the sample stage 104 are exhausted by the processing gas in the processing chamber 100, particles in the plasma, and reaction product particles flowing. It is an exhaust route.

  An exhaust valve 107 that is an exhaust unit of the processing chamber 100 includes a plurality of plate-like shutters 203 that can communicate or block between an exhaust pump 108 disposed below the inner space of the inner chamber 110. This is a shutter type exhaust valve that adjusts the exhaust gas flow rate and speed by variably adjusting the exhaust passage area opened by rotating the shutter 203. Thus, in the first embodiment, the exhaust means is disposed below the sample stage 104, particularly directly below. The plasma, processing gas, and reaction products in the space above the sample stage 104 in the inner chamber 109 are exhausted to the exhaust valve 107 through the space around the sample stage 104 and the space in the inner chamber 110 below the sample stage 104. Flowing.

  In the first embodiment, the vacuum exhaust means includes an exhaust valve 107 having a plurality of rotating shutters 203 and an exhaust pump 108 below the exhaust valve 107, and the exhaust valve 107 projects a substantially circular cross section directly below the sample stage 104. It is arranged in a region that is covered with the surface and inside. As shown in FIG. 1, the plurality of plate-like shutters 203 are arranged substantially horizontally (in the wafer surface direction) and rotate about the shafts 202 attached to the respective shutters 203. The area communicating between the opening and the exhaust pump 108 is adjusted. When these shafts 202 are rotated, the plates 203 of the shutters come into contact with each other or close to each other with a slight gap therebetween, and the opening can be substantially closed. Further, when each shutter plate 203 is substantially parallel to the vertical direction with the tip of the plate 203 in the direction of the sample stage 104 (upward), the area of communication becomes the largest. Although not shown, the exhaust valve 107 is provided with driving means such as a motor for adjusting the rotation of the shutter 203. The exhaust means adjusts the opening area of the shutter 203 and the driving of the exhaust pump 108 to adjust the amount of exhaust. And its speed.

  Further, an exhaust gate plate 130 is provided below the sample stage 104 and above the exhaust valve 107 so as to cover and open (open / shut off) the upper part of the exhaust opening gate 131 provided in the outer lower chamber 112. The exhaust gate plate 130 has a substantially disk shape and has at least one pair of arm portions extending outward at a peripheral edge of a part of the outer edge, and is disposed below the arm portion. When the upper end of the pusher moves up and down, the arm connected to the upper end is lifted / lowered to open / close the exhaust opening. The evacuation gate plate 130 has a projection surface below that within the projection surface of the upper sample stage 104, and a projection surface of the arm portion within the projection surface of the upper support beam 120, or at least one of them. The parts are arranged so as to overlap.

  FIG. 2 is a diagram schematically illustrating the configuration of the exhaust valve 117 according to the first embodiment of the present invention. FIG. 2A is a plan view schematically showing the configuration of the exhaust valve 117 as viewed from above. FIG. 2B is a cross-sectional view of the side surface of the exhaust valve 117.

  The exhaust valve 117 has an opening on the inside and a shutter 201 that increases and decreases the area of the opening by rotating around a main body 201 that constitutes an exhaust path and an axis 202 that is disposed inside the opening and extends across the opening. Each plate-like shutter 203 is composed of a disc 204 disposed at both ends in the direction of the axis 202 with a minute gap between the inner side wall of the main body 201. Inside the main body 201, a plurality of plate-like shutters 203 are arranged substantially horizontally (in the wafer surface direction), and the respective shutters 203 rotate about the shafts 202 attached to the respective shutters 203, thereby opening the outer chamber 112. And the area communicating with the exhaust pump 118 is adjusted. When these shafts 202 are rotated, the plates of the shutters 203 become parallel to each other in a substantially horizontal direction, and the opening is remarkably narrowed to be in a closed state.

  Plasma, processing gas, and reaction products (deposits) in the space above the sample stage 204 in the inner chamber 110 are exhausted through the exhaust valve 117, and this deposit adheres to the inner wall of the main body 201 and the shutter 203. . Conditions for easy adhesion include having a wide space and a low temperature part. For this reason, a deposit adheres to the inner wall of the main body 201 having a large space, and it is easy to grow. Such deposits on the inner wall surface come into contact with and collide with the edge that has moved when the shutter 203 is rotated, and are released by cracking or peeling off. It adheres to the surface of a substrate-like sample such as a mounted semiconductor wafer and becomes a foreign substance.

  With respect to such a problem, in the plasma processing apparatus of this embodiment, the discs 204 are arranged at both ends in the direction of the axis 202 where the shutter 203 rotates in order to suppress deposition growth. The disc 204 is attached with its center substantially aligned with the shaft 202, and the surface facing the inner side wall surface of the opening of the main body 201 is disposed with a minute gap between the side wall surface and the inner wall of the main body 201 and the shutter 203. The gap with the edge is made very small in the entire area that moves as the edge rotates, and the deposition growth rate in this area is slowed down. Moreover, the area which can be attached is reduced by enlarging the edge part of the shutter 203 and increasing the area of the inner wall of the opening facing through the minute gap. As a result, it is possible to suppress the growth of the deposit on the inner wall of the exhaust valve main body 201 and the deposition of this deposit and the plate of each shutter 203 to scrape the deposit and become the source of the deposit.

  In the above description, the deposition growth is suppressed by attaching the disc 204, but there are the following concerns. That is, if there are edges at the ends of the surface of the disc 204, deposits will accumulate at those locations, and if the ends of these discs 204 are close together, they will be placed on these ends during rotation. The deposited depots may come into contact with each other and be scraped to cause foreign matters. The countermeasure will be described below with reference to FIGS.

  FIG. 3 is a diagram showing details of a plurality of discs 204 attached to the end portions of the shutters 203 of the above-described embodiment and arranged with a minute gap from the inner wall of the exhaust valve main body 201. FIG. 3A is a diagram in which a disc (1) 301 is attached to the end of the shutter 203. Moreover, FIG.3 (b) is an enlarged view of a disc (1) 301 edge part.

  In the disc (1) 301, the corners are rounded so that the ends are arranged substantially the same as the ends of the shutter 203 in the width direction. Further, the center portion of the rounded end maintains a minute gap that is the same as the gap between the shutters 203. For this reason, since the deposit 302 is accumulated toward the position shown in the drawing having a large space, that is, toward the shutter 203 inside the opening, it is possible to suppress the scraping of the disks (1) 301 when rotating. Is done.

  Further, another member may be arranged in order to suppress the formation of deposits at the end of the disc 204. FIG. 4 is a diagram showing details of a plurality of discs 204 attached to the end portions of the respective shutters 203 of the present embodiment and arranged with a small gap from the inner wall of the exhaust valve main body 201. FIG. 4A is a view in which a disc (2) 401 is attached to the end of the shutter 203, and a wear prevention plate 402 is attached to the inner wall of the exhaust valve body 201. FIG. FIG.4 (b) is the figure which looked at (a) from the side surface. FIG.4 (c) is an enlarged view of the edge part of disc (2) 401.

  The outer diameter of the disc (2) 401 is made smaller than the width in the direction substantially perpendicular to the shaft 202 of the shutter 203. And the anti-wearing provided with the dent where the inner circumference formed along the upper outer edge of the disk (2) 401 is arranged above the disk (2) 401 so as to cover the end of the upper outer edge. A plate 402 is mounted on the inner wall surface of the opening. In a state in which the anti-wearing plate 402 is attached, the inner peripheral surface of the recess covers the end surface of the outer peripheral edge of the disc (2) 401 with a minute gap from above. For this reason, the outer periphery of the end surface of the outer edge of the disc (2) 401 becomes a minute gap, and the deposit 403 accumulates at the position shown in the drawing having a wide space. Further, in the vicinity of the portion where the adjacent shutter 203 and the end of the disc (2) 401 are closest to each other, a portion of the anti-wearing plate 402 is interposed between them, and there is a possibility that the depot contacts when rotating. The high portion becomes a minute gap, and the risk of scraping the disks (2) 401 when rotating is suppressed.

It is sectional drawing which shows the outline of a structure of the plasma processing apparatus of this invention. It is a figure which shows the outline of a structure of the exhaust valve of Example 1 of this invention. It is a figure which shows the detail of the disc (1) of the exhaust valve of Example 2 of this invention. It is a figure which shows the detail of the disk (2) of the exhaust valve of Example 3 of this invention.

Explanation of symbols

100 Processing chamber 101 Process gas line 102 Shut-off valve 103 Quartz plate (lid member)
104 Sample stage 107 Exhaust valve 108 Exhaust pump 109 Inner chamber 110 Inner chamber 111 Outer chamber 112 Outer chamber 113 Process gate valve 114 Atmospheric gate valve 120 Support beam 122 Driving means 125 Radio wave source part 126 Antenna 127 Coil 128 Dielectric 129 Buffer chamber 130 Exhaust gate plate 131 Exhaust opening gate 132 Discharge chamber 132 'Vacuum chamber 133 Discharge chamber side wall member (quartz inner cylinder)
134 Shower plate 142 Lid member 143 Vacuum transfer container 144 Controller 201 Main body 202 Shaft 203 Shutter 204 Disc 301 Disc (1)
302 Depot 401 Disc (2)
402 Protection plate 403 Depot

Claims (5)

  A vacuum vessel and an exhaust device that is disposed below the processing chamber in the vacuum chamber and exhausts and depressurizes the processing chamber are provided, and a wafer disposed in the processing chamber is generated using plasma generated in the processing chamber. A plasma processing apparatus for processing, disposed inside an opening communicating with the exhaust device and the processing chamber, attached to both ends of a plurality of plate members and plate members rotating around a predetermined axis, A plasma processing apparatus comprising: a plurality of discs arranged with a minute gap from an inner wall; and a regulator for adjusting the exhaust by rotation of the plate member.   2. The plasma processing apparatus according to claim 1, wherein ends of the plurality of adjacent discs are arranged with a minute gap therebetween.   3. The plasma processing apparatus according to claim 1, wherein the plate member has a rectangular shape and includes a rotation shaft at the center thereof. 4.   4. The plasma processing apparatus according to claim 1, wherein a corner portion of the outer edge of the disk is chamfered.   The plasma processing apparatus according to any one of claims 1 to 3, wherein a small gap is formed along an upper outer edge of the plurality of disks, and the anti-wearing device is attached so as to cover it from above. A plasma processing apparatus comprising a plate member.

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