JP5029435B2 - Mounting table structure and heat treatment apparatus - Google Patents

Description

  The present invention relates to a heat treatment apparatus and a mounting table structure for an object to be processed such as a semiconductor wafer.

In general, in order to manufacture a semiconductor integrated circuit, a desired integrated circuit is obtained by repeatedly performing various heat treatments such as a film forming process, an etching process, a heat treatment, a modification process, and a crystallization process on a target object such as a semiconductor wafer. Is supposed to form. When performing various processes as described above, a processing gas required corresponding to the type of the process, for example, a film forming gas in the case of a film forming process, an ozone gas or the like in the case of a reforming process, In the case of crystallization treatment, an inert gas such as N ₂ gas or O ₂ gas is introduced into the processing vessel.

  For example, in the case of a single wafer type heat treatment apparatus that performs heat treatment on a semiconductor wafer one by one, for example, a mounting table with a built-in resistance heater is installed in a processing container that can be evacuated. A predetermined processing gas is allowed to flow while a semiconductor wafer is placed on the upper surface, and various heat treatments are performed on the wafer under predetermined process conditions.

  By the way, in general, the mounting table is formed of an opaque ceramic material such as aluminum nitride (AlN), or a ceramic material for preventing contamination from the ceramic material or improving cleaning resistance. In some cases, the mounting table is formed of transparent quartz (Patent Documents 1 to 3). When the mounting table is formed of the transparent quartz, the shape of the heater wire of the resistance heater is projected on the back surface of the wafer as it is to prevent a large temperature non-uniform distribution in the wafer surface. In addition, for example, a thin opaque ceramic plate is installed as a soaking plate on the upper surface side of the mounting table, and a wafer is mounted on the upper surface of the soaking plate. Here, the soaking plate has a function of conducting heat to the wafer after absorbing the heat rays radiated from the heater wires and making the temperature distribution uniform.

Japanese Patent Laid-Open No. 06-260430 JP 2004-356624 A JP 2007-335425 A

  By the way, in a general processing apparatus for processing a semiconductor wafer, the substrate is moved for the purpose of preventing a positional deviation or the like from moving on a mounting table on which the semiconductor wafer is mounted during processing. A clamp ring member that is a holding member may be provided. The clamp ring member is formed in a ring shape with an opaque ceramic material such as AlN, for example, and the lower surface on the inner peripheral side of the clamp ring member is brought into contact with the upper surface side (bevel portion) of the peripheral portion of the wafer and lightly pressed. The positional deviation of the wafer W is prevented.

  However, in this case, the clamp ring member in contact with the wafer is slightly away from the upper surface of the mounting table, but is separated upward by, for example, several millimeters, and therefore tends to be lower than the wafer temperature. It is in. For this reason, the temperature of the peripheral part (bevel part) of the wafer tends to be lower than the inner part due to the movement of heat to the clamp ring member. For this reason, there has been a problem that the in-plane uniformity of the wafer temperature is lowered, and the in-plane uniformity of the heat treatment such as a film forming process on the wafer is degraded.

  The present invention has been devised to pay attention to the above problems and to effectively solve them. An object of the present invention is to provide a mounting table capable of improving the in-plane uniformity of heat treatment by increasing the in-plane temperature uniformity of the object to be processed even when the object to be processed is in contact with the clamp ring member. The object is to provide a structure and a heat treatment apparatus.

The invention according to claim 1, in mounting table structure for mounting the object to be processed in order to perform a predetermined heat treatment on the object to be processed in the processing vessel, for supporting the workpiece A mounting table formed of a transparent material , and heating provided in a heating area accommodated in the mounting table and having a diameter larger than the diameter of the mounting area of the object to be processed in order to heat the object to be processed A heating unit having a heater; and an upper surface of the mounting table , which is provided in the heating region, and the workpiece is directly placed on the upper surface and has a diameter smaller than the diameter of the heating region. A soaking plate made of a non-transparent material, and provided so as to be movable up and down above the peripheral portion of the mounting table in order to press the object to be processed to the mounting table side, and for heating directly by the heating means Set in the heating area Was a mounting table structure is characterized in that and a clamp ring mechanism having a clamp ring member made of opaque material extending outward from the average hot plate.

In this way, the mounting table is made of a transparent material, and the diameter of the soaking plate made of an opaque material provided on the upper surface side is set to be smaller than the diameter of the heating area of the heating means. The clamp ring member can be directly heated by heat rays to raise the temperature to a temperature equivalent to the object to be processed. Therefore, even if the object to be processed is in contact with the clamp ring member, the in-plane temperature uniformity of the object to be processed can be increased, and the in-plane uniformity of the heat treatment can be improved.

In this case, for example, as described in claim 2, the mounting table is provided upright by a support column .

For example , as described in claim 3, the outer peripheral end of the heat equalizing plate is located at the same position as the inner peripheral end of the clamp ring member or radially outward from it.
For example , as described in claim 4, the clamp ring member is provided in association with a push-up pin that lifts or lowers the object to be processed.
Further, for example , as described in claim 5, purge gas supply means is provided for supplying purge gas to a space formed between the clamp ring member and the upper surface of the mounting table.

Further, for example , as described in claim 6, the purge gas supply means includes a plurality of purge gas injection holes provided along a peripheral portion of the mounting table, and a purge gas supply flow path communicating with the purge gas injection holes. Have.
In addition, for example, as described in claim 7, the mounting table is supported by a cylindrical column, and the column forms a part of the purge gas supply flow path.
For example , as described in claim 8, the transparent material is made of one material selected from the group consisting of transparent quartz glass and transparent sapphire.

Also, for example , as described in claim 9, the opaque material is selected from the group consisting of ceramic material, opaque quartz glass, aluminum, aluminum alloy, titanium, titanium alloy, carbon, carbon and metal composite material. Made of material.

Invention, in the heat treatment apparatus for performing a predetermined heat treatment on the target object, and an exhaust capable made the process vessel, placing according to any one of claims 1乃optimum 9 table according to claim 10 A heat treatment apparatus comprising a structure and gas introduction means for introducing gas into the processing vessel.

According to the mounting table structure and the heat treatment apparatus according to the present invention, the following excellent operational effects can be exhibited.
A mounting table having a mounting table structure is formed of a transparent material, and the diameter of the heat- uniforming plate made of an opaque material provided on the upper surface side is made smaller than the diameter of the heating region of the heating means, and the heat- uniforming plate installed in the heating region Since the clamp ring member is set to exist above the outer region of the outer periphery of the metal, the clamp ring member is directly heated by the heat rays from the heating means, and the temperature is raised to a temperature equivalent to the object to be processed. be able to. Therefore, even if the object to be processed is in contact with the clamp ring member, the in-plane temperature uniformity of the object to be processed can be increased, and the in-plane uniformity of the heat treatment can be improved.

Hereinafter, an embodiment of a mounting table structure and a heat treatment apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view showing an example of a heat treatment apparatus using a mounting table structure according to the present invention, FIG. 2 is a plan view showing a mounting table having a mounting table structure, and FIG. 3 shows a main part of the mounting table having a mounting table structure. FIG. 4 is a simplified enlarged view showing a mounting table.

  As shown in the figure, this heat treatment apparatus 2 has a processing vessel 4 made of aluminum or aluminum alloy, for example, whose inside is substantially circular. A shower head portion 6 serving as a gas introduction means is provided on the ceiling portion in the processing container 4 to introduce a predetermined gas required, for example, a film forming gas, and is provided on the gas injection surface 8 on the lower surface. The processing gas is jetted toward the processing space S from the large number of gas injection holes 10A, 10B.

  In the shower head unit 6, gas diffusion chambers 12A and 12B divided into two hollow shapes are formed. After the processing gas introduced therein is diffused in the plane direction, each gas diffusion chamber 12A is formed. , 12B are blown out from the respective gas injection holes 10A, 10B communicated with each other. The entire shower head portion 6 is made of, for example, a nickel alloy such as nickel or Hastelloy (registered trademark), aluminum, or an aluminum alloy. The shower head unit 6 may have one gas diffusion chamber. A sealing member 14 made of, for example, an O-ring or the like is interposed at the joint between the shower head 6 and the upper end opening of the processing container 4 so that the airtightness in the processing container 4 is maintained. ing.

  In addition, a loading / unloading port 16 for loading / unloading a semiconductor wafer W as an object to be processed into / from the processing container 4 is provided on the side wall of the processing container 4, and the loading / unloading port 16 can be opened and closed in an airtight manner. A gate valve 18 is provided.

  An exhaust space 22 is formed at the bottom 20 of the processing container 4. Specifically, a large opening 24 is formed in the central portion of the container bottom 20, and a cylindrical partition wall 26 having a bottomed cylindrical shape extending downward is connected to the opening 24, and the above described inside An exhaust space 22 is formed. A mounting table structure 29, which is a feature of the present invention, is provided on the bottom portion 28 of the cylindrical partition wall 26 that partitions the exhaust space 22 so as to place the semiconductor wafer W as an object to be processed. It is done. Specifically, the mounting table structure 29 has a mounting table 32 bonded and fixed to the upper end of a cylindrical column 30 made of a transparent material such as transparent quartz glass. Details of the mounting table structure 29 will be described later.

  The opening 24 of the exhaust space 22 is set to be smaller than the diameter of the mounting table 32, and the processing gas flowing down outside the peripheral edge of the mounting table 32 circulates below the mounting table 32 to open the opening 24. To flow into. An exhaust port 34 is formed in the lower side wall of the cylindrical partition wall 26 so as to face the exhaust space 22. An exhaust pipe 36 having an exhaust pump (not shown) is provided in the exhaust port 34. It is connected so that the atmosphere in the processing container 4 and the exhaust space 22 can be exhausted.

  In the middle of the exhaust pipe 36, a pressure regulating valve (not shown) capable of opening degree control is provided. By automatically adjusting the valve opening degree, the inside of the processing container 4 is provided. The pressure can be maintained at a constant value or can be rapidly changed to a desired pressure.

  The mounting table 32 is mainly formed of a transparent material such as transparent quartz glass. As described above, the mounting table 32 is joined to the upper end portion of the cylindrical support column 30 by, for example, welding. Inside the mounting table 32, a heater 38 arranged in a predetermined pattern shape as a heating means is accommodated, for example, so as to be embedded. In this case, the heater 38 extends over at least a heater region having a diameter D2 (see FIG. 4) larger than the diameter D1 of the placement region on which the semiconductor wafer W is placed, that is, substantially in the plane direction of the placement table 32. It is provided over the entire area.

  Note that the diameter D1 of the mounting region is the same as the diameter of the wafer W. The heater 38 may be embedded in the transparent quartz glass constituting the mounting table 32, or the constituent material of the mounting table 32 is formed of two glass plates, and is accommodated so as to be sandwiched therebetween. Well, its structure does not matter. The heater 38 is connected to a power feed rod 40 inserted through the cylindrical column 30 and is supplied with power from a heater power source (not shown) for temperature control.

  The heater 38 is electrically divided into, for example, an inner zone and an outer zone that concentrically surrounds the outer zone, and temperature control (power control) can be performed individually for each zone. .

  A thin heat equalizing plate 42 made of an opaque material whose diameter is set smaller than the diameter D0 of the mounting table 32 is provided on the upper surface of the mounting table 32. The wafer W is placed directly. In this case, the diameter D2 of the heating region of the heater 38 is set to be larger than the diameter D3 of the soaking plate 42. 1 and 4 show the case where the diameter of the wafer W (the diameter D1 of the mounting area) and the diameter D3 of the soaking plate 42 are set to be the same.

  As the opaque material, for example, aluminum nitride (AlN) having a thickness of about 5 mm can be used. The mounting table 32 is provided with a purge gas supply means 43 for injecting a purge gas upward from the peripheral portion of the mounting table 32. Specifically, the purge gas supply means 43 includes a plurality of purge gas injection holes 44 provided along the circumferential direction in a region around the mounting table 32 and outside the mounting region having the diameter D1. (See FIG. 2). Each purge gas injection hole 44 is in communication with a purge gas supply channel 46 formed in the mounting table 32.

  As shown also in FIG. 2, the purge gas supply channel 46 communicates with the ring-shaped channel 46A and the ring-shaped channel 46A formed in a ring shape in communication with the purge gas injection holes 44 in common. As described above, the connecting path 46B is formed along the radial direction of the mounting table 32. The communication path 46B communicates with the column 30 through the communication hole 46C at the center of the mounting table 32. Has been.

In addition, an inert gas introduction hole 46D for supplying an inert gas as a purge gas into the support column 30 is formed at the lower portion of the support column 30, and the inert gas is introduced from the purge gas injection holes 44 as necessary. A gas such as N ₂ gas can be injected. As the inert gas, a rare gas such as Ar or He can be used instead of N ₂ .

  The mounting table 32 is provided with a clamp ring mechanism 48 for fixing the wafer W. Specifically, the clamp ring mechanism 48 includes a clamp ring member 50 that is provided so as to be movable up and down above the periphery of the mounting table 32 and presses the wafer W toward the mounting table 32.

  That is, the clamp ring member 50 is formed in a ring shape having a predetermined width by an opaque material, and a tapered surface 52 (see FIG. 3) inclined downward is formed at an inner peripheral end portion thereof. ing. The tapered surface 52 is brought into contact with the peripheral portion (also referred to as “bevel portion”) of the wafer W and pressed downward. As the opaque material, for example, aluminum nitride (AlN) can be used.

  In this case, as shown in FIG. 3, the outer peripheral end P <b> 1 of the soaking plate 42 is located at the same position as the inner peripheral end P <b> 2 of the clamp ring member 50, or radially outward therefrom. In the case shown in FIG. 3, the outer peripheral end P1 (the same position as the outer peripheral end of the wafer W) is located radially outward by several millimeters from the inner peripheral end P2.

  The clamp ring member 50 is supported by a plurality of, for example, three support rods 54 (only two are shown in FIG. 1) extending downward, and the lower end of each support rod 54 has a circular ring shape. For example, it is connected to a push-up ring 56 made of ceramics such as alumina. The push-up ring 56 is supported by an upper end portion of a lifting rod 60 provided through the container bottom 20, and the lifting rod 60 can be lifted and lowered by an actuator 62. As a result, the clamp rod member 50 is moved up and down by moving the lift rod 60 in the vertical direction, and the peripheral portion of the wafer W can be pressed down.

  In addition, an extendable bellows 64 is interposed in a through-hole at the bottom of the container of the lift rod 60 connected to the actuator 62, and the lift rod 60 moves up and down while maintaining the airtightness in the processing container 4. It can be done. Further, a plurality of, for example, three pin insertion holes 66 are formed in the mounting table 32 and the soaking plate 42 so as to penetrate in the vertical direction (only two are shown in FIG. 1). A push-up pin 68 that is bent in an L shape and inserted in a loosely fitted state is disposed in the pin insertion hole 66.

  Each push-up pin 68 is integrally connected so as to relate to the support rod 54 that supports the clamp ring member 50. Therefore, the wafer W can be lifted or lowered by moving up and down integrally with the lifting and lowering movement of the clamp ring member 50. Here, when the clamp ring member 50 is in contact with the upper surface of the peripheral portion of the wafer W and presses the wafer W by its own weight (see FIG. 3), the lower surface of the clamp ring member 50 and the upper surface of the mounting table 32. A minute space portion 70 is formed between the purge gas and the purge gas injection hole 44 to supply a purge gas to the minute space portion 70.

  Control of the overall operation of the heat treatment apparatus 2 configured in this way, for example, supply start and stop of each gas, flow rate control, process pressure control, wafer temperature control, etc., is an apparatus control unit comprising a computer or the like 72 is performed according to an instruction from 72.

Next, the operation of the heat treatment apparatus configured as described above will be described.
First, an unprocessed semiconductor wafer W is loaded into the processing container 4 through the gate valve 18 and the loading / unloading port 16 which are held by a transfer arm (not shown) and opened, and the wafer W is clamped by a clamp ring mechanism 48. After being transferred to the push-up pins 68 raised together with the clamp ring member 50, the push-up pins 68 are lowered to place the wafer W on the upper surface of the mounting table 32 and support it.

  At this time, the clamp ring member 50 and the push-up pin 68 are connected to each other and integrally move up and down, so that the clamp ring member 50 is also lowered simultaneously with the lowering of the push-up pin 68, and the inner peripheral portion is tapered. The surface 52 comes into contact with the peripheral part (bevel part) of the wafer W, and the wafer W is pressed downward by the weight of the clamp ring member 50.

In this way, a predetermined gas, for example, a film forming gas, flows from the shower head unit 6 serving as a gas introduction unit in a state where the wafer W is fixed on the heat equalizing plate 42 of the mounting table 32 by the pressing. It is supplied to the processing space S while being controlled, and the inside of the processing container 4 is maintained at a predetermined process pressure. For example, when forming a TiN film, TiCl ₄ gas and NH ₃ gas are supplied as film forming gases.

  Electric power is supplied to the heater 38 which is a heating means provided on the mounting table 32, and the wafer W is heated to a predetermined process temperature, for example, about several hundred degrees Celsius via the mounting table 32. In this way, for example, a predetermined thin film is formed on the surface of the wafer W by heat treatment. In this case, the heat from the heater 38 hits the heat equalizing plate 42 made of an opaque material, and heat is uniformly diffused in the surface direction to heat the wafer W placed on the upper surface by heat conduction.

  Here, in the conventional mounting table structure, as described above, the diameter of the soaking plate is large, and the clamp ring member 50 that presses the wafer W is separated from the upper surface of the mounting table 32. Since the heat rays emitted from the heat sink are absorbed by the soaking plate and do not reach the clamp ring member 50 sufficiently, the temperature of the clamp ring member 50 tends to be lower than the wafer temperature. There was a tendency for the temperature of the wafer to decrease from the wafer center side.

  On the other hand, in the case of the present invention, the diameter of the soaking plate 42 is set to be substantially the same as the diameter of the wafer W, and as a result, from the heater 38 positioned outside the soaking plate 42. The radiated heat rays (radiant heat) pass through the constituent material of the mounting table 32 made of a transparent material and the space 70 to reach the clamp ring member 50 made of an opaque material above, and directly reach the clamp ring member 50. Will be heated. Therefore, although the clamp ring member 50 and the mounting table 32 are not in direct contact with each other and a space portion 70 that inhibits heat conduction is formed between them, the clamp ring member 50 is The wafer is heated to substantially the same temperature as the wafer W.

  Therefore, even if the inner peripheral portion of the clamp ring member 50 is in contact with the peripheral portion of the wafer W, the temperature of the peripheral portion of the wafer W is not lowered, and the in-plane uniformity of the wafer temperature is maintained high. can do. In other words, the diameter D3 of the soaking plate 42 is set to be smaller than the diameter D2 of the heating region where the heater 38 is provided, and the upper clamp ring member 50 is heated by the heat rays from the heater 38. The clamp ring member 50 can be heated to a temperature higher than that of the conventional structure by direct heating.

  In this case, a length L1 (see FIG. 5A) in which the diameter of the heat equalizing plate 42 can be made larger than the outer peripheral end (edge) of the wafer W as in the modification showing the size of the heat equalizing plate shown in FIG. ) Is, for example, about 3 mm. If the length L1 is too long, the area of the clamp ring member 50 that receives the heat rays directly from the heater 38 becomes too small, and the temperature of the clamp ring member 50 is set to the wafer W. It will not be possible to raise the temperature sufficiently to this temperature.

On the other hand, as shown in FIG. 5B, the minimum value (lower limit) of the diameter of the soaking plate 42 is up to a position corresponding to the inner peripheral end of the clamp ring member 50. The length L2 between the outer peripheral end (edge) is about 3 mm.
Further, in this case, when the film forming gas enters the space portion 70 (see FIG. 3) formed between the clamp ring member 50 and the mounting table 52, an unnecessary adhesion film is formed here, and the heater is heated. The heat ray directly heating the clamp ring member 50 from 38 is blocked by the unnecessary adhesion film.

However, in the present invention, the purge gas supply means 43 is provided so that an inert gas such as N ₂ gas is supplied into the space 70 from the purge gas injection hole 44 provided in the peripheral portion of the mounting table 32. Therefore, the deposition gas can be prevented from entering the space 70. Specifically, the thickness of the space 70 is about 0.2 mm, and the length of the overlapping portion of the clamp ring member 50 and the periphery of the mounting table 32 is about 2 to 3 cm. Intrusion of the film forming gas into the space 70 can be substantially reliably prevented by the purge gas.

  Thus, according to the present invention, the mounting table 32 is formed of a transparent material, and the soaking plate 42 made of an opaque material provided on the upper surface side is set to be smaller than the diameter of the mounting table 32. The clamp ring member can be directly heated by the heat rays from the heater 38, which is a heating means, and the temperature can be raised to a temperature equivalent to the object to be processed. Therefore, even if the object to be processed is in contact with the clamp ring member, the in-plane temperature uniformity of the object to be processed can be increased, and the in-plane uniformity of the heat treatment can be improved.

  Actually, in the heat treatment apparatus using the mounting table structure according to the present invention, when a TiN film thin film was formed, the in-plane uniformity of the film thickness was about 4 to 5% in the case of the conventional apparatus. On the other hand, in the case of this invention, it was able to improve to about 2%.

In the above embodiment, the clamp ring member 50 and the support rod 54 are directly connected to each other. However, an elastic member such as a coil spring is interposed in the middle of the support rod 54, and the elastic force causes the above-described effect. The clamp ring member 50 may be pushed downward.
Moreover, in the said embodiment, although transparent quartz glass was used as a transparent material which comprises the mounting base 32, it is not limited to this, As said transparent material, 1 selected from the group which consists of transparent quartz glass and transparent sapphire. Materials can be used.

Moreover, in the said embodiment, although aluminum nitride was used as an opaque material which comprises the soaking | uniform-heating plate 42 and the clamp ring member 50, it is not limited to this, As said opaque material, a ceramic material, opaque quartz glass, aluminum, aluminum One material selected from the group consisting of alloys, titanium, titanium alloys, carbon, and composite materials of carbon and metal can be used. As the ceramic material, AlN, Al ₂ O ₃ , SiC, SiN, or the like can be used. The opaque quartz glass can be formed by mixing bubbles in the transparent glass.

In addition, although the film formation process has been described as an example of the heat treatment here, the present invention is not limited to this, and the present invention is applicable to all heat treatments such as etching treatment, oxidation diffusion heat treatment, annealing treatment, modification treatment, and crystallization treatment. Further, it can be applied to a heat treatment apparatus using plasma.
Although the semiconductor wafer is described as an example of the object to be processed here, the present invention is not limited thereto, and the present invention can be applied to a glass substrate, an LCD substrate, a ceramic substrate, and the like.

It is a cross-sectional block diagram which shows an example of the heat processing apparatus using the mounting base structure which concerns on this invention. It is a top view which shows the mounting base of a mounting base structure. It is the elements on larger scale which show the principal part of the mounting base of a mounting base structure. It is a simplified diagram showing a mounting table in a simplified manner. It is the elements on larger scale which show the principal part of the modification of a soaking plate.

Explanation of symbols

2 Heat treatment device 4 Processing vessel 6 Shower head (gas introduction means)
29 mounting table structure 30 support column 32 mounting table 38 heater (heating means)
42 Soaking plate 43 Purge gas supply means 44 Purge gas injection hole 46 Purge gas supply flow path 48 Clamp ring mechanism 50 Clamp ring member 68 Push-up pin 70 Space W Semiconductor wafer (object to be processed)

Claims (10)

In the mounting table structure for mounting the object to be processed in order to perform a predetermined heat treatment on the object to be processed in the processing container,
A mounting table formed of a transparent material to support the object to be processed;
A heating means having a heater provided in a heating area having a diameter larger than the diameter of the mounting area of the object to be processed and heated in the mounting table for heating the object to be processed;
It is an upper surface of the mounting table , and is provided in the heating region, and the workpiece is directly placed on the upper surface, and the soaking is made of an opaque material having a diameter smaller than the diameter of the heating region. The board,
In order to press the object to be processed to the mounting table side, it is provided so as to be movable up and down above the periphery of the mounting table, and the leveling unit provided in the heating region for heating directly by the heating means. A clamp ring mechanism having a clamp ring member made of an opaque material extending outward from the hot plate ;
A mounting table structure characterized by comprising: The mounting table structure according to claim 1, wherein the mounting table is provided upright by a support column. 3. The mounting table structure according to claim 1, wherein an outer peripheral end of the heat equalizing plate is located at the same position as the inner peripheral end of the clamp ring member or radially outward from the position. . The clamping ring member, mounting table structure according to any one of claims 1乃optimum 3, characterized in that said are provided in conjunction with the push-up pins to lower lifting or has to be processed. Mounting according to any one of claims 1乃optimum 4, wherein a purge gas supply means for supplying a purge gas is provided in a space portion formed between the upper surface of the clamp ring member and said mounting base Stand structure. Said purge gas supply means according to claim 5, characterized in that it comprises a plurality of purge gas injection holes provided along the periphery of the mounting table, wherein a purge gas supply channel communicating with the respective purge gas injection holes, the serial mounting of the mounting table structure. 7. The mounting table structure according to claim 6, wherein the mounting table is supported by a cylindrical column, and a part of the purge gas supply channel is formed in the column. The transparent material is a transparent quartz glass, the mounting table structure according to any one of claims 1乃optimum 7, characterized in that consists of one material selected from the group consisting of transparent sapphire. 2. The opaque material is made of one material selected from the group consisting of ceramic material, opaque quartz glass, aluminum, aluminum alloy, titanium, titanium alloy, carbon, and a composite material of carbon and metal. mounting table structure according to any one of乃Itaru 8. In a heat treatment apparatus for performing a predetermined heat treatment on a workpiece,
A processing vessel made evacuable;
A mounting table structure according to any one of claims 1乃Itaru 9,
Gas introduction means for introducing gas into the processing vessel;
A heat treatment apparatus comprising:

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