JP2007088176A - Substrate treating device, and method for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate treatment capable of raising uniform heating in a substrate, uniforming an in-plane temperature distribution in the substrate treatment, and raising the uniformity of thickness in depositing a film. <P>SOLUTION: A substrate treating device includes a treatment chamber 41 for treating the substrate 3, a support board 50 for supporting the substrate 3 inside the treatment chamber 41, and a heater 76 for heating the substrate 3 in the treatment chamber 41. A plurality of projections are arranged on the upper surface of the support board 50, and arrayed in a grid shape. The flatness of the upper surface of the support board is ≤0.015 mm in a circumferential direction and ≤0.025 mm in a radial direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a substrate processing apparatus for manufacturing a semiconductor device such as an IC by processing a substrate such as a silicon wafer and a method for manufacturing the semiconductor device.

  The process of manufacturing a semiconductor device such as an IC or LSI includes a process of forming an amorphous silicon film, a polysilicon film, or the like on a substrate by a thermal CVD method. For example, in order to generate an amorphous silicon film, film formation is performed at a low temperature. However, when film formation processing is performed in a region where activation energy is large using SiH4 gas or the like, the influence of the in-plane temperature distribution of the substrate is affected. It becomes easy to receive. For this reason, in order to improve the film thickness uniformity in the substrate surface, the uniformity of the in-plane temperature distribution of the substrate is required.

  The substrate is supported by a support plate in the processing chamber, and the substrate is heated by a heater through the support plate. The support plate functions as a soaking plate, and the heating uniformity of the substrate is determined by the heat transfer state between the support plate and the substrate. When the substrate is placed directly on the support plate, the temperature distribution of the support plate affects the temperature distribution of the substrate, and the heating state changes depending on the contact state between the support plate and the substrate, but the entire surface of the substrate is supported. It is difficult to uniformly contact the plate, and warping of the substrate during heating occurs. For this reason, uniform heating over the entire surface of the substrate is difficult.

  As shown in Patent Document 1, conventionally, a substrate is supported on a support plate via pins, a gap is formed between the support plate and the substrate, and the substrate is heated by radiant heat from the support plate. There is something like that.

  By forming a gap between the support plate and the substrate, the heating non-uniformity in the case of direct contact between the support plate and the substrate is eliminated, but heat conduction between the pin and the substrate, There is a change in radiant heat due to a change in the gap between the support plate and the substrate due to the undulation of the substrate between the pins, and there are still factors that hinder the uniform heating of the substrate.

JP 2003-77788 A

  In view of such circumstances, the present invention further improves the uniform heating property of the substrate, and aims to make the in-plane temperature distribution uniform in the substrate processing and to improve the uniformity of the film thickness.

  The present invention includes a processing chamber for processing a substrate, a support plate for supporting the substrate in the processing chamber, and a heater for heating the substrate in the processing chamber, and a plurality of convex portions are formed on the upper surface of the support plate. The convex portions are arranged in a lattice pattern, and the substrate processing apparatus has a flatness of the upper surface of the support plate of 0.015 mm or less in the circumferential direction and 0.025 mm or less in the radial direction.

  The present invention also includes a step of carrying the substrate into the processing chamber, and a plurality of convex portions provided on the upper surface of the support plate in the processing chamber, the convex portions being arranged in a lattice shape on the upper surface, and the supporting plate. Placing the substrate on the support plate having a flatness of the upper surface of 0.015 mm or less in the circumferential direction and 0.025 mm or less in the radial direction, and processing the substrate while heating the substrate; The present invention relates to a method for manufacturing a semiconductor device including a step of unloading from a processing chamber.

  According to the present invention, a processing chamber for processing a substrate, a support plate for supporting the substrate in the processing chamber, and a heater for heating the substrate in the processing chamber are provided, and a plurality of protrusions are formed on the upper surface of the support plate. The protrusions are arranged in a lattice pattern, and the flatness of the upper surface of the support plate is 0.015 mm or less in the circumferential direction and 0.025 mm or less in the radial direction. The uniform heating property of the substrate to be heated is improved, and an excellent effect is achieved in that the in-plane temperature distribution in the substrate processing is uniform and the uniformity of the film thickness is improved.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  An outline of a substrate processing apparatus to which the present invention is applied will be described with reference to FIGS.

  In the substrate processing apparatus to which the present invention is applied, a FOUP (front opening unified pod) is used as a carrier for transporting a substrate such as a wafer.

  In the following description, front, rear, left and right are based on FIG. That is, with respect to the paper shown in FIG. 1, the front is below the paper, the back is above the paper, and the left and right are the left and right of the paper.

  As shown in FIGS. 1 and 2, the substrate processing apparatus includes a first transfer chamber 1 configured in a load lock chamber structure that can withstand a pressure (negative pressure) less than atmospheric pressure such as a vacuum state. The casing 2 of the first transfer chamber 1 is formed in a box shape with a hexagonal shape in plan view and closed at both upper and lower ends. The first transfer chamber 1 is provided with a first wafer transfer device 4 for transferring the wafer 3 under a negative pressure. The first wafer transfer machine 4 is configured to be moved up and down by an elevator 5 while maintaining the airtightness of the first transfer chamber 1.

  The two side walls located on the front side of the six side walls of the housing 2 are connected to a carry-in spare chamber 6 and a carry-out spare chamber 7 through gate valves 8 and 9, respectively. The load lock chamber structure can withstand negative pressure. Further, a substrate placing table 11 for carrying-in chamber is installed in the preliminary chamber 6, and a substrate placing table 12 for carrying-out chamber is installed in the spare chamber 7.

  A second transfer chamber 13 used at substantially atmospheric pressure is connected to the front sides of the preliminary chamber 6 and the preliminary chamber 7 via gate valves 14 and 15. A second wafer transfer machine 16 for transferring the wafer 3 is installed in the second transfer chamber 13. The second wafer transfer device 16 is configured to be moved up and down by an elevator 17 installed in the second transfer chamber 13 and to be reciprocated in the left-right direction by a linear actuator 18. ing.

  As shown in FIG. 1, an orientation flat aligning device 19 is installed on the left side of the second transfer chamber 13. As shown in FIG. 2, a clean unit 21 for supplying clean air is installed above the second transfer chamber 13.

  As shown in FIG. 1 and FIG. 2, a wafer loading / unloading port 23 for loading / unloading the wafer 3 into / from the second transfer chamber 13 in the housing 22 of the second transfer chamber 13. A lid 24 for closing the wafer loading / unloading port 23 and a pod opener 25 are provided. The pod opener 25 includes a cap of a pod 27 placed on the IO stage 26 and a cap opening / closing mechanism 28 that opens and closes the lid 24 that closes the wafer loading / unloading port 23. The cap 24 and the lid 24 that closes the wafer loading / unloading port 23 are opened and closed by the cap opening / closing mechanism 28 to allow the wafer in and out of the pod 27 to be taken in and out. The pod 27 is supplied to and discharged from the IO stage 26 by an in-process transfer device (RGV) (not shown).

  As shown in FIG. 1, a first processing furnace 31 for performing a desired process on a wafer, and a second processing wall are disposed on two side walls located on the rear side of the six side walls of the housing 2. Are connected adjacent to each other. Each of the first processing furnace 31 and the second processing furnace 32 is constituted by a cold wall type processing furnace. The remaining two side walls of the six side walls in the housing 2 that are opposite to each other include a first cooling unit 33 as a third processing furnace and a fourth processing furnace. A second cooling unit 34 is connected to each other, and both the first cooling unit 33 and the second cooling unit 34 are configured to cool the processed wafer 3.

  Hereinafter, processing steps using the substrate processing apparatus having the above-described configuration will be described.

  In a state where 25 unprocessed wafers 3 are housed in the pod 27, the unprocessed wafer 3 is transported to the substrate processing apparatus for performing the processing process by the in-process transport apparatus. As shown in FIGS. 1 and 2, the transferred pod 27 is delivered and placed on the IO stage 26 from the in-process transfer device. A cap 24 for opening / closing the cap of the pod 27 and the wafer loading / unloading port 23 is removed by a cap opening / closing mechanism 28, and the wafer entrance / exit of the pod 27 is opened.

  When the pod 27 is opened by the pod opener 25, the second wafer transfer machine 16 installed in the second transfer chamber 13 picks up the wafer 3 from the pod 27 and carries it into the spare chamber 6, and the wafer is transferred. 3 is transferred to the substrate table 11. During the transfer operation, the gate valve 8 on the first transfer chamber 1 side is closed, and the negative pressure in the first transfer chamber 1 is maintained. When the transfer of the wafer 3 to the substrate table 11 is completed, the gate valve 14 is closed and the preliminary chamber 6 is exhausted to a negative pressure by an exhaust device (not shown).

  When the preliminary chamber 6 is depressurized to a preset pressure value, the gate valves 8 and 35 are opened, and the preliminary chamber 6, the first transfer chamber 1, and the first processing furnace 31 are communicated. Subsequently, the first wafer transfer machine 4 in the first transfer chamber 1 picks up the wafer 3 from the substrate table 11 and carries it into the first processing furnace 31. Then, a processing gas is supplied into the first processing furnace 31 and a desired processing is performed on the wafer 3.

  When the processing is completed in the first processing furnace 31, the processed wafer 3 is transferred to the first transfer chamber 1 by the first wafer transfer device 4 in the first transfer chamber 1. .

  Further, the first wafer transfer machine 4 carries the wafer 3 unloaded from the first processing furnace 31 into the first cooling unit 33 and cools the processed wafer 3.

  When the wafer 3 is transferred to the first cooling unit 33, the first wafer transfer machine 4 again uses the wafer 3 prepared in advance in the substrate table 11 of the preliminary chamber 6 to the first processing furnace. 31 is transferred by the above-described operation, a processing gas is supplied into the first processing furnace 31, and a desired processing is performed on the wafer 3.

  When a preset cooling time elapses in the first cooling unit 33, the cooled wafer 3 is transferred from the first cooling unit 33 to the first transfer chamber by the first wafer transfer device 4. 1 is carried out.

  After the cooled wafer 3 is unloaded from the first cooling unit 33 to the first transfer chamber 1, the gate valve 9 is opened. The first wafer transfer device 4 transports the wafer 3 unloaded from the first cooling unit 33 to the preliminary chamber 7 and transfers it to the substrate table 12, and then the preliminary chamber 7 includes the gate valve. 9 is closed.

  When the preliminary chamber 7 is closed by the gate valve 9, the inside of the preliminary chamber 7 for discharge is returned to substantially atmospheric pressure by an inert gas. When the inside of the preliminary chamber 7 is returned to substantially atmospheric pressure, the gate valve 15 is opened, and the lid 24 that closes the wafer loading / unloading port 23 corresponding to the preliminary chamber 7 of the second transfer chamber 13; An empty cap of the pod 27 placed on the IO stage 26 is opened by the pod opener 25. Subsequently, the second wafer transfer device 16 in the second transfer chamber 13 picks up the wafer 3 from the substrate table 12 and carries it out to the second transfer chamber 13, and the second transfer chamber 13. The wafers are accommodated in the pod 27 through the 13 wafer loading / unloading ports 23. When the storage of the 25 processed wafers 3 in the pod 27 is completed, the cap 24 of the pod 27 and the lid 24 for closing the wafer loading / unloading port 23 are closed by the pod opener 25. The closed pod 27 is transported from above the IO stage 26 to the next process by an in-process transport device.

  By repeating the above operation, the wafers 3 are sequentially processed. The above operation has been described by taking the case where the first processing furnace 31 and the first cooling unit 33 are used as an example, but the case where the second processing furnace 32 and the second cooling unit 34 are used. The same operation is performed for.

  In the above-described substrate processing apparatus, the spare chamber 6 is used for carrying in and the spare chamber 7 is used for carrying out. However, the spare chamber 7 may be used for carrying in and the spare chamber 6 may be used for carrying out. Moreover, the 1st processing furnace 31 and the 2nd processing furnace 32 may perform the same process, respectively, and may perform another process. When performing another process in the first process furnace 31 and the second process furnace 32, for example, after performing a process on the wafer 3 in the first process furnace 31, another process is performed in the second process furnace 32. Processing may be performed. In the case where another processing is performed in the second processing furnace 32 after the processing on the wafer 3 is performed in the first processing furnace 31, the first cooling unit 33 (or the second cooling unit 34) is installed. You may make it go through.

  As shown in FIG. 3, the first processing furnace 31 according to the present invention is configured as a single wafer type CVD furnace (single wafer type cold wall type CVD furnace), and a wafer (semiconductor wafer) as a substrate to be processed. ) A chamber 42 in which a processing chamber 41 for processing 3 is formed is provided. The chamber 42 is formed in a cylindrical shape in which an upper cap 43, a cylindrical cup 44, and a lower cap 45 are combined, and upper and lower end surfaces are closed.

  A wafer loading / unloading port 47 opened and closed by a gate valve 46 is opened horizontally in the middle of the cylindrical wall of the cylindrical cup 44 of the chamber 42. The wafer loading / unloading port 47 is a substrate to be processed. A certain wafer 3 is formed so as to be carried into and out of the processing chamber 41 by the wafer transfer device 4. That is, the wafer 3 is mechanically supported from below by the wafer transfer device 4 and is carried into and out of the processing chamber 41 through the wafer carry-in / out opening 47. The carried-in wafer 3 is transferred to a susceptor (substrate support plate). 50).

  As will be described later, a large number of support pins protrude from the upper surface of the susceptor 50, and the wafer 3 is placed on the susceptor 50 via the support pins. The upper surface of the susceptor 50 and the lower surface of the wafer 3 are The required gap is formed.

  An exhaust port 55 connected to an exhaust device (not shown) composed of a vacuum pump or the like is opened at the upper portion of the wall surface of the cylindrical cup 44 facing the wafer loading / unloading port 47 so as to communicate with the processing chamber 41. The interior of the processing chamber 41 is exhausted by an exhaust device.

  Further, an exhaust buffer space 56 communicating with the exhaust port 55 is formed in an annular shape at the upper part of the cylindrical cup 44, and acts so as to uniformly exhaust the entire surface of the wafer 3 together with the cover plate 57. Yes.

  The cover plate 57 is provided so as to face the susceptor 50 from above so as to cover the edge portion of the wafer 3, and the cover plate 57 is a CVD film formed on the edge portion of the wafer 3. Used to control

  A shower head 58 for supplying a processing gas is integrally incorporated in the upper cap 43 of the chamber 42. That is, gas supply pipes 59 are inserted in the ceiling wall of the upper cap 43, and the open / close valves 61 and 62 for introducing process gases A and B such as source gas and purge gas into the gas supply pipes 59, for example. A gas supply device 60 composed of a flow control device (mass flow controller = MFC) 63 and 64 is connected. A disc-shaped shower plate (hereinafter referred to as a plate) 65 is horizontally fixed to the lower surface of the upper cap 43 with a space from the gas supply pipe 59. Gas outlets (hereinafter referred to as outlets) 66 are provided so as to be uniformly arranged over the entire surface and circulate through the upper and lower spaces.

  A buffer chamber 67 is formed by an inner space defined by the inner surface of the upper cap 43 and the upper surface of the plate 65, and the buffer chamber 67 is configured to receive the processing gas 68 introduced into the gas supply pipe 59 as a whole. It diffuses equally and blows out from each said blower outlet 66 in the shape of a shower equally.

  An insertion hole 69 is formed in a circular shape at the center of the lower cap 45 of the chamber 42, and a support shaft 71 formed in a cylindrical shape on the center line of the insertion hole 69 is provided in the processing chamber 41 from below. It is inserted. The support shaft 71 is moved up and down by a lifting mechanism (lifting means) 72 using an air cylinder device or the like.

  A heating unit 73 is concentrically arranged at the upper end of the support shaft 71 and is horizontally fixed so as to face the susceptor 50 from below. The heating unit 73 is moved up and down by the support shaft 71. It has become. That is, the heating unit 73 includes a heater support 74 formed in a disk shape, and the heater support 74 is fixed concentrically to the upper end opening of the support shaft 71. A plurality of electrodes 75 which also serve as support columns are vertically erected on the upper surface of the heater support 74, and a heater (divided and controlled in a plurality of regions) is formed in a disk shape at the upper end of the plurality of electrodes 75. A heating means) 76 is attached. Electrical wires 77 for the plurality of electrodes 75 are inserted into the hollow portion of the support shaft 71.

  Further, a reflector 78 is supported by the heater support 74 below the heater 76, and heat generated from the heater 76 is reflected to the susceptor 50 side to improve heating efficiency.

  A radiation thermometer 79 as temperature detecting means is introduced from the lower end of the support shaft 71, and the tip of the radiation thermometer 79 is installed on the back surface of the susceptor 50 with a predetermined gap. The radiation thermometer 79 is composed of a combination of a rod made of quartz and an optical fiber, detects radiation emitted from the back surface of the susceptor 50 (for example, the back surface corresponding to the divided region of the heater 76), and detects the susceptor 50. (The temperature of the wafer 3 can also be calculated based on the relationship between the temperature of the wafer 3 and the susceptor 50 acquired in advance), and the heating state of the heater 76 is controlled based on the calculation result. Yes.

  On the outside of the support shaft 71 of the insertion hole 69 of the lower cap 45, a rotating shaft 81 formed in a cylindrical shape having a larger diameter than the support shaft 71 is disposed concentrically and below the processing chamber 41. The rotating shaft 81 is moved up and down together with the support shaft 71 by the lifting mechanism 72 using an air cylinder device or the like. A rotary drum 82 is concentrically arranged at the upper end of the rotary shaft 81 and fixed horizontally, and the rotary drum 82 is rotated by the rotary shaft 81. That is, the rotating drum 82 includes a rotating plate 83 formed in a donut-shaped flat plate and a rotating cylinder 84 formed in a cylindrical shape, and the inner peripheral edge of the rotating plate 83 has a cylindrical shape. The rotating cylinder 84 is concentrically fixed to the outer peripheral edge portion of the upper surface of the rotating plate 83. The upper end of the rotating cylinder 84 of the rotating drum 82 is covered with the susceptor 50 formed in a disk shape using silicon carbide, aluminum nitride or the like so as to close the upper end opening of the rotating cylinder 84. .

  As shown in FIG. 3, a wafer lifting / lowering device 85 is installed on the rotary drum 82. The wafer elevating device 85 is composed of two elevating rings formed in a circular ring shape and protruding pins (substrate protruding means) 86, 87 protruding from each other. , A rotation side ring) is disposed concentrically with the support shaft 71 on the rotating plate 83 of the rotating drum 82. On the lower surface of the rotating ring, a plurality (three in the present embodiment) of the protruding pins (hereinafter referred to as rotating pins) 87 are arranged at equal intervals in the circumferential direction and face downward in the vertical direction. The rotation-side pins 87 are slidably inserted into the guide holes 88 that are arranged on the rotation plate 83 on a line concentric with the rotation cylinder 84 and opened in the vertical direction. Yes. The lengths of the rotation-side pins 87 are set to be equal to each other so that the rotation-side ring can be protruded horizontally, and are set to correspond to the protrusion amount of the wafer 3 from above the susceptor 50. The lower end of each rotation-side pin 87 is detachably opposed to the bottom surface of the processing chamber 41, that is, the upper surface of the lower cap 45.

  On the heater support 74 of the heating unit 73, another lifting ring (hereinafter referred to as a heater side ring) formed in a circular ring shape is disposed concentrically with the support shaft 71. On the lower surface of the heater-side ring, a plurality of protruding pins (hereinafter referred to as three heater-side pins) 86 (hereinafter referred to as heater-side pins) 86 are arranged at equal intervals in the circumferential direction and face downward in the vertical direction. Each heater-side pin 86 is slidably fitted in each guide hole 89 that is arranged on the heater support 74 on a line concentric with the support shaft 71 and opened in the vertical direction. ing. The lengths of the heater-side pins 86 are set equal to each other so that the heater-side ring can be pushed up horizontally, and their lower ends are opposed to the upper surface of the rotation-side ring with an appropriate air gap. That is, the heater side pin 86 does not interfere with the rotation side ring when the rotation drum 82 rotates.

  Further, a plurality of protruding pins (hereinafter referred to as protruding portions) 86 (hereinafter referred to as protruding portions) 86 are vertically arranged on the upper surface of the heater side ring at equal intervals in the circumferential direction. The upper end of the protruding portion 86 is opposed to the heater 76 and the insertion hole 80 of the susceptor 50. The lengths of the protrusions 86 are set to be equal to each other so that the wafer 3 placed on the susceptor 50 through the heater 76 and the insertion hole 80 of the susceptor 50 from below is floated horizontally from the susceptor 50. ing. The length of the protruding portion 86 is set such that the upper end of the protruding portion 86 does not protrude from the upper surface of the heater 76 when the heater side ring is seated on the heater support 74. In other words, the protruding portion 86 does not interfere with the susceptor 50 when the rotating drum 82 rotates, and does not prevent the heater 76 from being heated.

  As shown in FIG. 3, the chamber 42 is horizontally supported by a plurality of columns 91. Each elevating block 92 is fitted to the column 91 so as to be movable up and down, and the elevating platform is moved up and down by an elevating drive device (not shown) using an air cylinder device or the like between the elevating blocks 92. 93 is erected. A susceptor rotating mechanism 94 is installed on the lifting platform 93, and a bellows 90 is interposed between the susceptor rotating mechanism 94 and the chamber 42 so that the outside of the rotating shaft 81 is hermetically sealed. It is installed.

  A brushless DC motor is used for the susceptor rotating mechanism (rotating means) 94 installed on the lifting platform 93, and an output shaft (motor shaft) is formed as a hollow shaft and configured as the rotating shaft 81. . The susceptor rotating mechanism 94 includes a housing 95, and the housing 95 is installed on the elevating base 93 vertically upward. A stator (stator) 96 composed of an electromagnet (coil) is fixed to the inner peripheral surface of the housing 95. That is, the stator 96 is configured by winding a coil wire (enamel-coated copper wire) 97 around an iron core (core) 98. A lead wire (not shown) is electrically connected to the coil wire 97 through a not-shown insertion hole formed in the side wall of the housing 95, and the stator 96 is a brushless DC motor driver (not shown). ) Is supplied to the coil wire 97 through a lead wire to form a rotating magnetic field.

  Inside the stator 96, a rotor (rotor) 99 is arranged concentrically with an air gap (gap) being set, and the rotor 99 is rotatable on the housing 95 via upper and lower ball bearings 101. It is supported by. That is, the rotor 99 includes a cylindrical main body 102, an iron core (core) 103, and a plurality of permanent magnets 104. The rotating shaft 81 is fixed to the main body 102 so as to rotate integrally with a bracket 105. Has been. The iron core 103 is fitted and fixed to the main body 102, and the plurality of permanent magnets 104 are fixed to the outer periphery of the iron core 103 at equal intervals in the circumferential direction. A plurality of magnetic poles arranged in an annular shape are formed by the iron core 103 and the plurality of permanent magnets 104, and the rotating magnetic field formed by the stator 96 cuts the plurality of magnetic poles, that is, the magnetic fields of the permanent magnets 104. As a result, the rotor 99 rotates.

  The upper and lower ball bearings 101 are respectively installed at upper and lower ends of the main body 102 of the rotor 99, and a gap for absorbing thermal expansion of the main body 102 is appropriately set in the upper and lower ball bearings 101. ing. The gap is set to 5 μm to 50 μm in order to absorb the thermal expansion of the main body 102 and suppress the minimum shakiness. The clearance of the ball bearing 101 means a clearance generated on the opposite side when the ball is brought to either the outer race or the inner race.

  The facing surface of the stator 96 and the rotor 99 is opposed to a cover 106 which is an outer and inner surrounding member constituting a double cylindrical wall, and the inner peripheral surface of the housing 95 and the main body 102 are opposed to each other. And a predetermined air gap (gap) is set between each of the covers 106. The cover 106 is made of stainless steel, which is a non-magnetic material, and is formed in a cylindrical shape with a very thin cylinder wall. The housing 95 and the main body 102 are electrically connected to the upper and lower ends of the cylinder. It is securely and uniformly fixed over the entire circumference by beam welding. The cover 106 is made of stainless steel, which is a non-magnetic material, and is extremely thin. Therefore, the cover 106 not only prevents the magnetic flux from diffusing, but also reduces the motor efficiency. Corrosion of the permanent magnet 104 of the child 99 can be prevented, and contamination inside the processing chamber 41 by the coil wire 97 and the like can be surely prevented. The cover 106 completely isolates the stator 96 from the inside of the processing chamber 41 in a vacuum atmosphere by surrounding the stator 96 in an airtight seal state.

  The susceptor rotating mechanism 94 is provided with a magnetic rotary encoder 107. The magnetic rotary encoder 107 includes a detection ring 108 as a detection object made of a magnetic material, and the detection ring 108 is formed in a circular ring shape using a magnetic material such as iron. On the outer periphery of the detection ring 108, a large number of teeth as detection parts are arranged in an annular shape.

  A magnetic sensor 109 for detecting each tooth which is a detected portion of the detected ring 108 is installed at a position of the housing 95 facing the detected ring 108. A gap (sensor gap) between the front end surface of the magnetic sensor 109 and the outer peripheral surface of the detected ring 108 is set to 0.06 mm to 0.17 mm. The magnetic sensor 109 is configured to detect a change in magnetic flux at these opposed positions as the detected ring 108 rotates by using a magnetoresistive element. The detection result of the magnetic sensor 109 is transmitted to a brushless DC motor, that is, a drive control unit of the susceptor rotation mechanism 94, and is used for position recognition of the susceptor 50 and used to control the rotation amount of the susceptor 50. .

  The first processing furnace 31 in the embodiment of the present invention includes a main control unit 115 including a gas control unit 111, a drive control unit 112, a heating control unit 113, a temperature detection unit 114, and the like. . The gas control unit 111 is connected to the MFCs 63 and 64 and the open / close valves 61 and 62 to control gas flow rate and supply. The drive control unit 112 is connected to the susceptor rotating mechanism 94 and the elevating block 92 and controls the driving thereof. The heating control unit 113 is connected to the heater 76 via the electric wiring 77 and controls the heating condition of the heater 76. The temperature detection unit 114 is connected to the radiation thermometer 79, detects the temperature of the susceptor 50, and is used for heating control of the heater 76 in cooperation with the heating control unit 113.

  Next, by describing the operation of the processing furnace according to the above configuration, a film forming process in a method for manufacturing a semiconductor device which is an example of an embodiment of the present invention will be described.

  When the wafer 3 is carried out and carried in, the rotary drum 82 and the heating unit 73 are lowered to the lower limit position by the rotary shaft 81 and the support shaft 71. Since the lower end of the rotation side pin 87 of the wafer elevating device 85 abuts against the bottom surface of the processing chamber 41, that is, the upper surface of the lower cap 45, the rotation side ring rises relative to the rotation drum 82 and the heating unit 73. To do. The raised rotation side ring lifts the heater side ring by pushing up the heater side pin 86. When the heater side ring is lifted, the three protrusions 86 standing on the heater side ring pass through the heater 76 and the insertion hole 80 of the susceptor 50, and the wafer 3 placed on the upper surface of the susceptor 50 is removed. It is supported from below and floats up from the susceptor 50.

  When the wafer lifting device 85 floats the wafer 3 from the upper surface of the susceptor 50, a tweezer (not shown), which is a substrate holding plate provided in a wafer transfer machine (not shown in FIG. 3), is loaded into the wafer. It is inserted under the wafer 3 from the carry-out port 47. The tweezer inserted below the wafer 3 moves up to receive the wafer 3. Upon receiving the wafer 3, the tweezer leaves the wafer loading / unloading port 47 and unloads the wafer 3 from the processing chamber 41. Then, the wafer transfer machine that unloads the wafer 3 by the tweezers transfers the wafer 3 to a predetermined storage location such as an empty wafer cassette outside the processing chamber 41.

  Next, the wafer transfer device receives the wafer 3 to be subjected to the next film formation process from a predetermined storage location such as an actual wafer cassette by a tweezer and carries it into the processing chamber 41 from the wafer loading / unloading port 47. The tweezers transport the wafer 3 above the susceptor 50 to a position where the center of the wafer 3 coincides with the center of the susceptor 50. When the wafer 3 is transported to a predetermined position, the tweezer is lowered slightly to transfer the wafer 3 to the susceptor 50. The tweezer that has transferred the wafer 3 to the wafer lifting / lowering device 85 is moved out of the processing chamber 41 from the wafer loading / unloading port 47. When the tweezer leaves the processing chamber 41, the wafer loading / unloading port 47 is closed by a gate valve (gate valve) 46.

  When the gate valve 46 is closed, the rotary drum 82 and the heating unit 73 are raised by the lifting mechanism 72 through the rotary shaft 81 and the support shaft 71 with respect to the processing chamber 41. As the rotary drum 82 and the heating unit 73 are raised, the protrusion pins 86 and 87 are lowered relative to the rotary drum 82 and the heating unit 73, and as shown in FIG. It is completely transferred onto the susceptor 50. The rotating shaft 81 and the support shaft 71 are stopped at a position where the upper end of the protruding portion 86 is at a height close to the lower surface of the heater 76.

  On the other hand, the processing chamber 41 is exhausted by an exhaust device (not shown) connected to the exhaust port 55. At this time, the vacuum atmosphere in the processing chamber 41 and the external atmospheric pressure atmosphere are isolated by the bellows 90.

  Subsequently, the rotating drum 82 is rotated by the susceptor rotating mechanism 94 via the rotating shaft 81. That is, when the susceptor rotating mechanism 94 is operated, the rotating magnetic field of the stator 96 cuts off the magnetic fields of the plurality of magnetic poles of the rotor 99, so that the rotor 99 rotates. The rotating drum 82 is rotated by the rotating shaft 81 that has been made. At this time, the rotational position of the rotor 99 is detected every moment by the magnetic rotary encoder 107 installed in the susceptor rotating mechanism 94 and transmitted to the drive control unit 112. Based on this signal, the rotational speed and the like are determined. Be controlled.

  During the rotation of the rotating drum 82, the rotating side pin 87 is separated from the bottom surface of the processing chamber 41, and the heater side pin 86 is separated from the rotating side ring. However, the heating unit 73 can be maintained in a stopped state. That is, in the wafer elevating device 85, the rotation side ring and the rotation side pin 87 are rotated together with the rotation drum 82, and the heater side ring and the heater side pin 86 are stopped together with the heating unit 73. Yes.

  When the temperature of the wafer 3 rises to the processing temperature and the exhaust amount of the exhaust port 55 and the rotational operation of the rotary drum 82 are stabilized, the processing gas 68 is supplied to the supply pipe as shown by solid arrows in FIG. 59. The processing gas 68 introduced into the gas supply pipe 59 flows into the buffer chamber 67 functioning as a gas dispersion space and diffuses radially outward in the radial direction from each gas outlet 66 of the shower plate 65. Each becomes a substantially uniform flow and blows out toward the wafer 3 in a shower shape. The processing gas 68 blown out in the form of a shower from the outlet 66 group passes through the space above the cover plate 57 and is sucked into the exhaust port 55 via the exhaust buffer space 56 and exhausted.

  At this time, since the wafer 3 on the susceptor 50 supported by the rotating drum 82 is rotating, the processing gas 68 blown out in a shower form from the outlet 66 group is evenly distributed over the entire surface of the wafer 3. It will be in the state which contacts. Since the processing gas 68 contacts the entire surface of the wafer 3 evenly, the film thickness distribution and film quality distribution of the CVD film formed on the wafer 3 by the processing gas 68 are uniform over the entire surface of the wafer 3.

  Since the heating unit 73 is not rotated by being supported by the support shaft 71, the temperature distribution of the wafer 3 heated by the heating unit 73 while being rotated by the rotating drum 82 is spread over the entire surface. It is controlled uniformly throughout. In this way, the temperature distribution of the wafer 3 is uniformly controlled over the entire surface, so that the film thickness distribution and film quality distribution of the CVD film formed on the wafer 3 by the thermochemical reaction are uniform over the entire surface of the wafer 3. Be controlled.

  Note that, up to one example, the processing conditions to be processed in the first processing furnace 31 in the embodiment of the present invention are as follows: a film forming temperature of 450 ° C. to 650 ° C. in the film formation of a doped / non-doped silicon film; Processing pressure 270 Pa to 50000 Pa (during film formation), processing gas silane-based gas (SiH4, Si2 H6) dopant gas (PH3, B2 H6), inert gas (N2), gas supply amount is silane-based gas ~ 2 slm, dopant gas ~ 1 slm, inert gas to 20 slm.

  When a predetermined processing time selected in advance elapses, the operation of the susceptor rotation mechanism 94 is stopped. At this time, the rotational position of the susceptor 50, that is, the rotor 99 is monitored every moment by the magnetic rotary encoder 107 installed in the susceptor rotating mechanism 94, so that the susceptor 50 is set in advance. Is stopped exactly. That is, the protrusion 86, the heater 76, and the insertion hole 80 of the susceptor 50 are matched accurately and with good reproducibility.

  When the operation of the susceptor rotating mechanism 94 is stopped, as described above, the rotating drum 82 and the heating unit 73 are carried in by the lifting platform 93 via the rotating shaft 81 and the support shaft 71. Lowered to the unloading position. As described above, the wafer 3 is lifted from above the susceptor 50 by the action of the wafer lifting device 85 during the lowering. At this time, since the protrusion 86 is aligned with the insertion hole 80 of the heater 76 and the susceptor 50 accurately and with good reproducibility, the protrusion 86 pushes up the susceptor 50 and the heater 76. No mistakes will occur.

  Thereafter, the above-described operation is repeated to form a CVD film on the next wafer 3.

  Next, the susceptor 50 will be described with reference to FIGS.

  The susceptor 50 is made of high-purity carbon (heat conduction (90 W / m · k) is good, deformation is large) or aluminum nitride (heat conduction (60 W / m · k) is low, deformation is small, processing In addition, other materials (for example, quartz, silicon carbide, etc.) can also be used, and a wafer placement surface 51 is formed on the upper surface of the susceptor 50. A required number of convex portions 52 are formed. The susceptor 50 and the projections 52 are integrally formed by cutting or the like from a block made of high purity carbon or aluminum nitride. The arrangement of the projections 52 is a lattice shape, for example, as shown in FIG. As shown in the figure, they are arranged at the vertices of a regular quadrangle, and are arranged so that the distances between the adjacent convex portions 52 are equal. Note that the four convex portions 52a are provided at positions deviating from the regular quadrangular vertexes so that the convex portions 52 support the periphery of the wafer 3.

  In addition, the lattice shape is not limited to a regular square, and the convex portion 52 may be a lattice shape disposed at each vertex of the regular triangle, and the distance between adjacent convex portions 52 is equal, or Any lattice shape that is substantially equal may be used.

  The wafer 3 is placed on the susceptor 50 through the convex portion 52.

  As described above, the susceptor 50 is heated by the heat generated by the heater 76, and the wafer 3 is further heated by the susceptor 50.

  The heating mechanism of the wafer 3 includes heat radiation from the wafer mounting surface 51, heat conduction due to solid contact between the convex portion 52 and the wafer 3, and gas between the wafer mounting surface 51 and the wafer 3. There is intervening heat conduction, heat radiation is affected by the distance between the wafer mounting surface 51 and the wafer 3, and heat conduction due to solid contact between the convex portion 52 and the wafer 3 is performed by the convex portion 52 and the wafer 3. It is influenced by the contact state with the projection, the arrangement state of the convex portion 52, and the like.

  Further, the distance between the wafer mounting surface 51 and the wafer 3 is affected by the flatness of the wafer mounting surface 51 and the height accuracy of the convex portion 52, and the contact state between the convex portion 52 and the wafer 3. Are influenced by the area and shape of the upper end of the convex portion 52, the distance between the adjacent convex portions 52, and the like.

  In the present invention, the heat conduction by the solid contact between the convex portion 52 and the wafer 3 is made uniform, and the variation in the distance between the wafer mounting surface 51 and the wafer 3 is limited to make the heating uniform by the heat radiation. Has improved.

  For example, in order to achieve uniform heat conduction by solid contact between the convex portion 52 and the wafer 3, the number of the convex portions 52 is several tens with a configuration in which an 8-inch wafer and a 12-inch wafer are placed. About 27, preferably about 80. Further, the distance between the adjacent convex portions 52 is set to, for example, 30 mm, and the arrangement is symmetrical in at least two orthogonal directions with respect to the center of the wafer mounting surface 51.

  Further, the shape of the convex part 52 is, for example, a truncated cone (hereinafter referred to as a truncated cone), the diameter of the bottom surface is φ1 mm or less, preferably φ0.5 mm to φ0.3 mm, and the top surface diameter is φ1 mm or less φ0.4 mm to φ0.2 mm. The lower limit of the diameter of the bottom surface and the upper surface is determined by the material of the susceptor 50 and the processing method, and the lower limit is different depending on other processing methods such as electric discharge machining other than cutting.

By setting the contact area of the upper surface of the convex part 52 to 0.04π mm ² , the amount of heat transfer due to the solid contact of the convex part 52 is suppressed, and the number of the convex parts 52 is increased and adjacent to each other. By equalizing the distance between the convex parts 52, the heat transfer by the solid contact is made uniform. The contact area of each of the convex portions 52 is preferably limited to a predetermined value or less in consideration of the heated area of the entire wafer 3, and is not more than 1.8 × 10 ⁻⁶ times the area of the wafer 3. It is preferable that Further, regarding the contact area of the convex portion 52, the material of the wafer 3 and the susceptor 50, the thermal conductivity, and the like should be taken into consideration. In short, it is sufficient that the heat transfer amount due to the solid contact can be suppressed. In the present invention, the wafer is a silicon wafer and the susceptor 50 is made of high-purity carbon or aluminum nitride.

  Further, since the heat transfer amount from the convex portion 52 is suppressed, the heat transfer is dominated by heat radiation and gas heat transfer, and the influence on the heat distribution of the wafer 3 due to non-uniform heat transfer due to solid contact. Less.

  Next, the management of the flatness of the wafer mounting surface 51 that affects the heat transfer by heat radiation and the management of the height accuracy of the convex portion 52 are performed by the susceptor 50 in addition to the processing of the convex portion 52. Since it is finished in one piece by processing, accuracy control is easy.

  For example, in order to limit the variation in the distance between the wafer mounting surface 51 and the wafer 3, the flatness of the wafer mounting surface 51 is 25 μm or less in the circumferential direction, preferably 15 μm or less, and 30 μm or less in the radial direction. Preferably, it is finished with an accuracy of 25 μm or less.

  Here, the flatness of the wafer mounting surface 51 is limited in the circumferential direction and the radial direction. However, in machining, there are circumferential undulations and radial undulations, and the influence of both undulations. This prevents the error from increasing.

  The height accuracy of the convex portion 52 is 0.015 mm or less, preferably 0.015 mm to 0.01 mm over the entire wafer mounting surface 51. The height of the convex portion 52 (h: see FIG. 6). ) Is 0.1 mm to 0.05 mm.

  More specifically, the accuracy of the height of the convex portion 52 is divided into areas having a radius of 30 mm or less, a radius of 30 mm to 70 mm, a radius of 70 mm to 120 mm, and a radius of 120 mm to 150 mm of the susceptor 50. 0.015 mm or less, preferably 0.015 mm to 0.01 mm, and between each area 0.015 mm or less, preferably 0.015 mm to 0.01 mm.

  The flatness is defined in JIS B 0621, and refers to the magnitude of the deviation of the plane portion from the geometric plane. When the plane portion is sandwiched between two parallel geometric planes. The distance between the two planes is expressed as the distance between the two planes (unit: mm or μm). That is, in the present embodiment, the susceptor flatness means 360 points of the susceptor plane (φ30, φ60, φ90, φ120, φ150, φ180, φ210, susceptor upper surface (plane) at the center of the susceptor. It is the difference between the maximum value and the minimum value of the measured values when the heights of 10 points on the circumference of φ240, φ270, and φ300 are measured.

  In the present embodiment, the pin height accuracy is the measurement of the height of the apex portion of each of the 80 pins with respect to the upper surface of the susceptor at the center of the susceptor and the height of the flat portion where the pin contacts. The difference between the maximum value and the minimum value of the measured value.

  Hereinafter, the uniformity of the film thickness when the wafer is processed by the susceptor 50 in which the convex portions 52 are formed will be described.

  First, the flatness of the wafer mounting surface 51, the height accuracy of the convex portion 52, and the film thickness uniformity will be described with reference to FIG. 7 shows the film thickness and film thickness uniformity when the wafer 3 is processed by three sets of susceptors A, B, and C having different flatness of the wafer mounting surface 51 and height accuracy of the convex portion 52. The processing conditions are as follows: doped / non-doped silicon film, film formation temperature 450 ° C. to 650 ° C., process pressure 270 Pa to 50000 Pa (during film formation), process gas silane-based gas (SiH 4, Si 2 H 6), dopant gas (PH3, B2 H6), inert gas (N2), and gas supply amount are silane-based gas to 2 slm, dopant gas to 1 slm, and inert gas to 20 slm.

  As inferred from the processing results, the film thickness uniformity is influenced by the flatness of the susceptor and the height accuracy of the convex portion, and the flatness of the susceptor is 0.015 mm (15 μm) or less in the circumferential direction and in the radial direction. Uniformity σ3% or less is achieved when the height accuracy of the projection is 0.025 mm (25 μm) or less and 0.015 mm (15 μm) or less, and the flatness of the susceptor is 10 μm or less in the circumferential direction and 10 μm in the radial direction. Hereinafter, the uniformity σ2% or less is achieved when the height accuracy of the convex portion is 15 μm or less.

  Next, referring to FIG. 8, the height of the convex portion 52, the diameter of the upper surface (contact area of the upper end of the convex portion 52), and the uniformity of the film thickness will be described.

  In FIG. 8, the used susceptor 50 is No. 1-No. 12 and no. 4, no. For comparison, the array of the convex portions 52 is arranged in a concentric multiple circle shape as shown in FIG. 9 for comparison, and the distance between the adjacent convex portions 52 is not the same. No. For comparison, the convex portion 52 is not provided for comparison. The processing conditions are the same as described above.

  As shown in FIG. 8, when the convex portion 52 has a diameter of 0.4 mm and a height of 0.1 mm, the film formation uniformity is good, and the convex portion 52 has a diameter of 1 mm. In this case, the uniformity is deteriorated when the height is 0.2 mm, the uniformity decreases in the direction in which the diameter of the convex portion 52 increases, and the height of the convex portion 52 increases. It can be judged that the uniformity tends to decrease.

  Therefore, from the result shown in FIG. 8, the film formation uniformity is improved when the diameter of the convex portion 52 is 0.4 mm or less and the height is 0.1 mm or less. Furthermore, when the diameter of the convex portion 52 is 1 mm, the support trace of the convex portion 52 may be transferred on the film formation. From this point, the smaller the diameter of the convex portion 52, the better results. Is obtained.

  Further, in the film formation at a temperature of 630 ° C. or higher (high temperature film formation), there is little influence on the uniformity due to the height accuracy of the convex portion, but in the film formation at a temperature of 630 ° C. or lower (low temperature film formation), The flatness of the mounting surface 51 and the height accuracy of the convex portions have a great influence on the uniformity.

  Furthermore, with respect to the arrangement of the convex portions 52, a case where the distances between the adjacent convex portions 52 are arranged in the same lattice shape, and a case where the distances between the adjacent convex portions 52 are arranged in a concentric multiple circle are not equal. In comparison, the film thickness uniformity is further improved when the convex portions 52 are arranged in a lattice pattern. In an arrangement in which the distances between adjacent convex portions 52 are not equal, it can be determined that the uniformity of heat transfer in solid contact is impaired.

  Note that the shape of the convex portion 52 is not limited to a truncated cone, but a hemispherical shape shown in FIG. 10A, a cylindrical shape shown in FIG. 10B, a conical shape shown in FIG. There may be.

It is a plane sectional view showing an example of a substrate processing device with which the present invention is carried out. It is a sectional side view of the same substrate processing apparatus. It is an elevational sectional view showing a processing furnace in the substrate processing apparatus. It is a top view of the susceptor in this processing furnace. It is a side view of this susceptor. It is an enlarged view of the convex part of this susceptor. It is a figure which shows the film-forming result processed with the substrate processing apparatus. It is a figure which shows the film-forming result processed with the substrate processing apparatus. It is a top view of the susceptor which shows the other arrangement | sequence of a convex part. (A) (B) (C) is a figure which shows the other shape of a convex part, respectively.

Explanation of symbols

3 Wafer 31 First Processing Furnace 41 Processing Chamber 50 Susceptor 51 Wafer Placement Surface 52 Projection 76 Heater

Claims (2)

  A processing chamber for processing the substrate; a support plate for supporting the substrate in the processing chamber; and a heater for heating the substrate in the processing chamber. A plurality of convex portions are provided on the upper surface of the support plate, The substrate processing apparatus, wherein the convex portions are arranged in a lattice pattern, and the flatness of the upper surface of the support plate is 0.015 mm or less in the circumferential direction and 0.025 mm or less in the radial direction.   A step of carrying the substrate into the processing chamber, and a plurality of convex portions are provided on the upper surface of the support plate in the processing chamber, the convex portions are arranged in a lattice pattern on the upper surface, and the flatness of the upper surface of the support plate is A step of placing the substrate on the support plate that is 0.015 mm or less in the circumferential direction and 0.025 mm or less in the radial direction, processing the substrate while heating the substrate, and unloading the processed substrate from the processing chamber. And a method of manufacturing a semiconductor device.

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