JP6663526B2 - Heat treatment equipment - Google Patents

Description

  The present invention relates to a heat treatment apparatus, and more specifically, to a heat treatment apparatus effective for use in a step of performing a heat treatment on a work such as a silicon wafer which is a raw material of a semiconductor chip or the like.

  Generally, when a plurality of wafers, which are works, are arranged vertically in a reaction tube using a heat treatment apparatus having a vertical reaction tube and a heater installed around the reaction tube, a reaction by-product is formed in the reaction tube. It has been known that a large amount adheres to the lower part of the body.

  In the conventional heat treatment apparatus, since maintenance for removing such reaction by-products by cleaning is frequently performed, there has been a problem that productivity is lowered.

  There is also a type in which an annular adapter for attaching a process gas introduction tube or the like to the reaction tube is attached to the lower end of the reaction tube. However, since this adapter is far from the heater disposed around the reaction tube and is exposed to the outside air, It is easy to cool and reactive by-products easily adhere to the inner surface of the adapter.

  Therefore, a tube made of quartz (a deposition delay tube), which is close to the inner peripheral portion of the adapter, is erected on the closing member that seals the bottom surface of the reaction tube, and reactive by-products are deposited in this tube. It has been proposed to suppress the adhesion of reaction by-products to the adapter (see Patent Document 1).

JP 2011-129567 A

  However, in the countermeasure of Patent Document 1, the surface of the closing member, which is located farthest from the heater in the reaction chamber and has a remarkable temperature drop, on the reaction chamber side is not covered with the deposition delay tube. On the surface of the closing member on the side of the reaction chamber, reaction by-products grow in the form of a film on the surface of the closing member, similarly to the CVD process on the work surface.

The closing member is usually made of stainless steel, while the growth film of the reaction by-product is, for example, SiO _{2. The} thermal expansion coefficient of the former is 10 ⁻⁵ [1 / ° C.] (average of 0 to 100 ° C.). Is 10 ⁻⁷ [1 / ° C.], and there is a great difference. Therefore, when the closing member is separated from the lower end of the reaction tube at the time of loading / unloading the wafer, the temperature of the surface of the closing member on the side of the reaction chamber decreases, and due to a difference in thermal expansion coefficient, 10 [μm However, there has been a problem that film peeling occurs when the film thickness is less than about [1], and particles are generated, thereby shortening the maintenance cycle.

  The present invention has been made in view of such problems, and a heat treatment apparatus capable of suppressing a growth of a film thickness of a reaction by-product on a closing member that seals a reaction chamber and extending a maintenance cycle. The purpose is to provide.

  The heat treatment apparatus of the present invention has a reaction tube, a holder, a closing member, and a film formation delay cover. A reaction chamber for accommodating a work is formed in the reaction tube. The holder holds the work in the reaction chamber. The closing member supports the holder and seals the reaction chamber. The film formation delay cover is made of quartz and covers the surface of the closing member on the reaction chamber side.

  According to this configuration, the reaction by-product conventionally growing on the surface of the closing member on the reaction chamber side preferentially adheres to the quartz film-forming delay cover that covers the closing member. It is possible to greatly delay (suppress) the growth of the film thickness. Further, since the film formation delay cover is made of quartz, peeling of reaction by-products is suppressed, and as a result, generation of particles can be reduced. In addition, the film formation delay cover on which the reaction by-products are deposited can be easily replaced by removing it from the closing member.

  In such a heat treatment apparatus, there is a type in which an air supply adapter is disposed between a reaction tube and a closing member. A connection port to which a gas supply pipe for supplying a process gas to the reaction chamber is connected is formed on the side of the gas supply adapter. Since this air supply adapter is usually made of a metal such as stainless steel having high heat resistance, reaction by-products tend to accumulate on the inner peripheral portion of the air supply adapter on the reaction chamber side as in the case of the closing member.

  Therefore, in the heat treatment apparatus of the present invention, the film formation delay cover is formed in a bottomed cylindrical shape having a side surface portion that is closely opposed to the inner peripheral portion of the air supply adapter. By doing so, the reaction by-products, which had conventionally accumulated on the inner peripheral portion of the air supply adapter, now preferentially accumulate on the side surface of the film formation delay cover. Can be delayed (suppressed).

  Furthermore, the heat treatment apparatus of the present invention includes an inner pipe open at both ends supported by the air supply adapter in the reaction tube, and an exhaust jacket disposed between the air supply adapter and the reaction tube, and the gas supply pipe is provided. The process gas is supplied from the lower end of the inner pipe into the inner pipe. According to this configuration, the process gas introduced from the gas supply pipe to the lower end in the inner pipe rises in the inner pipe. In this process, the work held by the holder arranged in the inner tube is processed by the process gas. Further, the process gas rises and exits from the upper end of the inner tube to the outside of the inner tube. Then, the process gas descends in the space between the reaction tube and the inner tube, and is discharged from the exhaust port of the exhaust jacket to the outside of the apparatus.

  In this type of heat treatment apparatus, a new process gas before passing through the workpiece is always supplied to the lower part of the reaction chamber, so that reaction by-products adhere to the reaction chamber side of the closing member and the air supply adapter. It will be easier. Therefore, a film formation delay cover is useful.

  In the heat treatment apparatus of the present invention, the process gas can be evenly distributed to all the workpieces, and the processing efficiency can be improved.

  According to the present invention, it is possible to suppress the growth of the film thickness of the reaction by-product on the closing member that seals the reaction chamber, and to lengthen the maintenance cycle.

FIG. 1 is a schematic sectional view showing a heat treatment apparatus according to an embodiment of the present invention. It is a top view of the principal part of the same heat processing apparatus. It is a perspective view which shows a film-forming delay cover. It is an exploded view of a film formation delay cover.

  Hereinafter, a heat treatment apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the heat treatment apparatus 10 includes a reaction tube 1, an inner tube 2, an exhaust jacket 3, an air supply adapter 4, a holder 5, a closing member 6, a heating mechanism 7, a rotation mechanism 8, and a film formation delay cover 20. Prepare.

  The reaction tube 1 is a cylindrical tube and is arranged vertically. The upper end of the reaction tube 1 is closed by a dome-shaped ceiling, and the lower end is open. A reaction chamber 11 for accommodating the work W is formed in a space inside the reaction tube 1.

  An inner tube 2 is installed inside the reaction tube 1. The inner tube 2 is a cylindrical tube and is arranged vertically. The upper and lower ends of the inner tube 2 are open. The inner pipe 2 is supported by an air supply adapter 4 described later.

  A heating mechanism 7 for heating the reaction chamber 11 is provided outside the reaction tube 1. In the present embodiment, the heating mechanism 7 includes a heater 71, a frame 72, and a heat insulating material 73. The frame 72 is a structure that surrounds the periphery of the reaction tube 1 and separates the inner space from the atmosphere. The frame 72 is formed of a heat-resistant material such as stainless steel. A heat insulator 73 is lined with the frame 72. The heater 71 is installed on the outer periphery of the reaction tube 1. When the heater 71 is embedded in a heat insulating material 73 surrounding the outer periphery of the reaction tube 1 as shown in the figure, the holding member of the heater 71 can also serve as the heat insulating material 73.

  The exhaust jacket 3 is an annular member and is attached to the lower end of the reaction tube 1. The exhaust jacket 3 is formed of a material having rigidity and heat resistance such as stainless steel. An exhaust port 31 is provided on a side surface of the exhaust jacket 3. The space between the reaction tube 1 and the exhaust jacket 3 is sealed by a gasket (not shown).

  The air supply adapter 4 is an annular member and is attached to the lower end of the exhaust jacket 3. The air supply adapter 4 is formed of a material having rigidity and heat resistance such as stainless steel. A connection port 41 for connecting the air supply nozzle 12 is formed on a side surface of the air supply adapter 4. The space between the exhaust jacket 3 and the air supply adapter 4 is sealed by a gasket (not shown).

  In the present embodiment, there are two air supply nozzles 12, and the two air supply nozzles 12 are attached to connection ports 41 provided at two opposing sides of the side surface of the annular air supply adapter 4 to form a reaction chamber. 11 is inserted.

  The upper end of the air supply adapter 4 protrudes toward the reaction chamber 11, and an inner tube supporting portion 42 is formed at the upper end of the protruding end. The inner pipe 2 is vertically supported by the inner pipe support portion 42 of the air supply adapter 4.

  In the present embodiment, the air supply nozzle 12 uses an L-shaped tube bent at 90 degrees. One end of the air supply nozzle 12 is a gas inlet 121 that opens horizontally. The gas inlet 121 is connected to a process gas supply device (not shown) outside the heat treatment device 10. The other end of the air supply nozzle 12 is a gas outlet 122 that opens vertically upward. The gas outlet 122 opens inside the lower end of the inner tube 2 in the reaction chamber 11. The gas supply nozzle 12 only needs to be able to feed gas into the reaction chamber, and may use a straight pipe extending horizontally.

  The reaction chamber 11 is a space formed inside the air supply adapter 4, the exhaust jacket 3, and the reaction tube 1. In the reaction chamber 11, a space formed inside the air supply adapter 4 and the inner tube 2 reaches near the ceiling of the reaction tube 1, and outside the space, a donut sandwiched between the inner tube 2, the reaction tube 1, and the exhaust jacket 3. A space is formed. The two spaces communicate with each other at the upper part of the reaction chamber 11.

  The closing member 6 is a plate-like member that seals the lower end of the reaction chamber 11, and is formed of a rigid and heat-resistant material such as stainless steel. The lower end of the annular air supply adapter 4 forming the bottom of the reaction chamber 11 provides a furnace port of the reaction chamber 11 and serves as a carry-in / out port for the workpiece W. The closing member 6 is arranged at the lower end of the air supply adapter 4. The space between the air supply adapter 4 and the closing member 6 is sealed with a seal (not shown). The closing member 6 is configured to be able to move up and down by an elevator device (not shown), and automatically opens and closes a furnace port of the reaction chamber 11.

  The holder 5 is a rack that holds the work W. In the present embodiment, the holder 5 is configured as a multi-stage rack capable of holding a plurality of works W at equal intervals in a horizontal posture.

  The holding tool 5 is mounted on the closing member 6, so that the holding tool 5 is moved in and out of the reaction chamber 11 as the closing member 6 moves up and down, so that the work W can be easily processed or replaced.

  The rotation mechanism 8 is installed on the side of the closing member 6 opposite to the reaction chamber 11. The turntable 14 is rotatably disposed on the reaction chamber 11 side of the closing member 6 while slightly floating from the closing member 6. The shaft 82 is fixed to the center of the bottom surface of the turntable 14 through a through hole 6 </ b> A penetrating the center of the closing member 6. In addition, a bearing 13 is disposed in the through hole 6A of the closing member 6, which also serves to seal the furnace port of the reaction chamber 11. The shaft 82 is supported by the bearing 13.

  The holder 5 is fixed on the turntable 14 with the central axes thereof aligned. When the turntable 14 rotates by the operation of the rotation mechanism 8, the holder 5 rotates at the same rotation speed. Thereby, the plurality of works W held by the holder 5 can be rotated in the reaction chamber 11.

  In the above configuration, when the heat treatment apparatus 10 is operated, the heater 71 generates heat, and the work W is rotated by the rotation mechanism 8 (arrow S). The temperature of the reaction chamber 11 can be monitored by the thermocouple 15, and is maintained in an appropriate temperature range by adjusting the amount of heat from the heater 71.

  When a process gas is introduced from the gas inlet 121 of the air supply nozzle 12 (arrow R1), the process gas is supplied upward from the gas outlet 122 of the air supply nozzle 12 to the lower end in the inner pipe 2 (arrow R2). The process gas rises in the inner pipe 2 (arrow R3), and is used for processing the workpiece W held by the holder 5 in the process. The exhaust of the process gas after the treatment flows from the upper end of the inner pipe 2 to the outside of the inner pipe 2 (arrow R4), descends in the space between the inner pipe 2 and the reaction pipe 1 (arrow R5), and is discharged from the exhaust port 31 to the outside of the apparatus. (Arrow R6).

  The film formation delay cover 20 is made of quartz, and is detachably attached to the closing member 6 so as to cover the surface (the upper surface in FIG. 1) of the closing member 6 on the reaction chamber 11 side as shown in FIG. . Since the film formation delay cover 20 aims at delaying the growth of the thickness of the reaction by-product on the closing member 6, the simplest shape may be a disk covering the upper surface of the closing member 6.

  In the present embodiment, as shown in FIG. 3, the deposition delay cover 20 is formed in a bottomed cylindrical shape having a side surface. The side surface portion of the film formation delay cover 20 is closely opposed to the inner peripheral portion of the air supply adapter 4 arranged above the closing member 6. Accordingly, it is possible to suppress not only the growth of the film thickness of the reaction by-product on the closing member 6 but also the accumulation of the reaction by-product on the inner peripheral portion of the air supply adapter 4 formed of stainless steel. .

  In the present embodiment, as shown in FIG. 3, the film formation delay cover 20 is formed as a cylinder having a large diameter at the lower part and a small diameter at the upper part. This shape is similar to the shape of the inner peripheral portion of the air supply adapter 4 (see FIG. 1) (the upper end portion protrudes toward the center of the reaction chamber 11). As a result, the area of the bottom surface of the film formation delay cover 20 that covers the closing member 6 also increases, so that a wide range of the bottom of the reaction chamber 11 including the air supply adapter 4 can be covered by the film formation delay cover 20. .

  A large hole 23 is formed at the center of the bottom surface of the film formation delay cover 20 so as to correspond to the through hole 6A of the closing member 6 (see FIG. 1). Further, two small holes 24A and 24B for attachment are provided on the bottom surface of the film formation delay cover 20. Bosses (not shown) project from the upper surface of the closing member 6 corresponding to the small holes 24A and 24B. When the film formation delay cover 20 is attached to the closing member 6, these bosses are connected to the small holes 24A. , 24B, it is possible to accurately attach to a predetermined position. The two small holes 24A and 24B are displaced in the radial direction and the circumferential direction on the bottom surface of the film formation delay cover 20, and the small hole 24B closer to the center is a thermocouple 15 penetrating the closing member 6 (FIG. 1). ) Also serves as a hole to be inserted.

  A pair of cutouts 22A and 22B are formed at opposing locations on the side surface of the deposition delay cover 20. As shown in FIG. 2, the cutouts 22 </ b> A and 22 </ b> B are provided as escape portions of the air supply nozzle 12 attached to the air supply adapter 4 and inserted into the reaction chamber 11. The number and position of the notches provided in the film formation delay cover 20 correspond to the number and arrangement of the air supply nozzles 12. The cutouts 22A and 22B reduce the area of the side surface of the film deposition delay cover 20, but a square tube that follows the shape of the cutouts 22A and 22B is used for the air supply nozzle 12 disposed in the cutouts 22A and 22B. It is possible to reduce functional loss by taking such measures.

  As shown in FIG. 4, the film formation delay cover 20 is formed by combining two pieces 21A and 21B equally divided by a straight line having a central angle of 180 degrees passing through the center of the bottom surface. The division into two is an example, and may be divided into three or more pieces. The number of divisions is set according to, for example, the number of cutouts formed in the film formation delay cover 20, that is, the number of air supply nozzles 12.

  Assembling holes 26A and 26B are formed on the bottom surfaces of the two pieces 21A and 21B, respectively, across the joint. Two pairs of holes 26A and 26B are prepared corresponding to the linear joints. After the two pieces 21A and 21B are assembled into a completed shape, the two pieces 21A and 21B are joined together by inserting the pin portions 251 of the quartz fixed plate 25 into the holes 26A and 26B. The assembly of the film deposition delay cover 20 can be completed only by fitting without using a fixing tool such as a screw, so that the assembly is easy.

  In the present invention, by attaching the film-forming delay cover 20 made of quartz to the closing member 6, the reaction by-product comes to adhere preferentially to the film-forming delay cover 20 made of quartz that covers the closing member 6. Therefore, it is possible to significantly delay (suppress) the film growth on the closing member 6.

  Specifically, before the deposition delay cover 20 was installed, 1000 or more particles were generated per workpiece W due to the growth of the reaction by-product film thickness of 10 μm or less. By installing 20, even if it exceeds 20 μm, the number of particles can be reduced to about 10 particles. This makes it possible to lengthen the maintenance cycle. In addition, the film deposition delay cover 20 on which the reaction by-products are deposited can be removed from the closing member 6 and easily replaced with a new one.

  If the surface of the film formation delay cover 20 is made uneven by sandblasting, the surface area increases, and as a result, the effect of reducing the film thickness of the reaction by-products can be expected, which also prevents peeling.

  The description of the above embodiment is illustrative in all aspects and should not be construed as limiting. The scope of the present invention is defined by the terms of the claims, rather than the embodiments described above. Further, the scope of the present invention is intended to include meanings equivalent to the claims and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 Reaction tube 2 Inner tube 3 Exhaust jacket 4 Air supply adapter 5 Holder 6 Closing member 6A Through hole 7 Heating mechanism 8 Rotation mechanism W Work 10 Heat treatment device 11 Reaction chamber 12 Air supply nozzle 13 Bearing 14 Turntable 15 Thermocouple 20 Membrane delay cover 21A, 21B Piece 22A, 22B Notch 23 Large hole 24A, 24B Small hole 25 Fixed plate 26A, 26B Hole 31 Exhaust port 41 Connection port 42 Inner tube support 71 Heater 72 Frame 73 Heat insulator 82 Shaft 121 Gas Inlet 122 Gas outlet 251 Pin section

Claims (4)

A reaction tube in which a reaction chamber for accommodating the work is formed;
A holder for holding the work in the reaction chamber,
A closing member that supports the holding tool and seals the reaction chamber,
A film-forming delay cover made of quartz, which covers a surface of the closing member on the reaction chamber side and is detachably provided to the closing member,
An air supply adapter disposed between the reaction tube and the closing member,
With
The air supply adapter has a side surface formed with a connection port to which a gas supply pipe for supplying a process gas to the reaction chamber is connected,
The film formation delay cover is a bottomed cylindrical shape having a side surface portion facing and proximate to an inner peripheral surface of the side surface portion of the air supply adapter, and approaches from the upper end of the side surface portion toward the center of the reaction chamber. A cutout through which the gas supply pipe connected to the connection port is formed in the side surface portion and the protruding portion of the film formation delay cover. , Heat treatment equipment.   The heat treatment apparatus according to claim 1, wherein the film formation delay cover is configured to be divided into at least two, and the number of divisions is set corresponding to the number of the gas supply pipes.   The heat treatment apparatus according to claim 2, wherein the film formation delay cover is configured by connecting a number of pieces corresponding to the number of divisions with a fixing plate. An inner tube open at both ends supported by the air supply adapter in the reaction tube,
An exhaust jacket disposed between the air supply adapter and the reaction tube, the exhaust jacket having a side surface portion formed with an exhaust port,
Further comprising
The heat treatment apparatus according to claim 1, wherein the gas supply pipe is configured to introduce a process gas into the inner pipe from a lower end of the inner pipe.

Images