JPH07335578A - Method and apparatus for heat treatment - Google Patents

Abstract

PURPOSE:To execute a heat treatment whose uniformity inside a face is high when an object to be treated, e.g. a semiconductor wafer, is heated rapidly up to a heat-treatment temperature so as to be heat-treated. CONSTITUTION:A heating source is installed at the outside of a treatment chamber, and a wafer W on a wafer-holding part inside the treatment chamber is heated rapidly up to a temperature near, e.g. 1200 deg.C. A conveyance means 4 which conveys the wafer W to the wafer-holding part from a conveyance chamber at the side part of the treatment chamber is provided with temperature- regulating bodies 51, 52 which are faced respectively with the surface and the rear surface of the wafer W, a heating fluid is made to flow into, and the wafer W is heated preliminarily up to, e.g. 400 to 600 deg.C. When the wafer is exposed to a rapid heating atmosphere, the difference in a temperature between the central part and the peripheral edge part is small because the wafer is heated preliminarily. Consequently, a temperature unstable region immediately before reaching a heat treatment temperature is short, and a thermal history is small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment method and a heat treatment apparatus.

[0002]

2. Description of the Related Art As semiconductor devices become finer and more highly integrated, the thickness of each layer of the device is becoming thinner, while semiconductor wafers (hereinafter referred to as "wafers") are also changed from 6-inch size to 8-inch or 12-inch size. Therefore, the development of ultra-thin film technology for large areas has become an important issue. In addition, for example, in the oxide film of the capacitor insulating film, the formation of the gate oxide film, or the diffusion process of impurity ions, the film quality, the film thickness, and the diffusion depth are greatly affected by the thermal budget (thermal history). It is necessary to suppress the heat treatment.

Here, in the vertical heat treatment, which is one of the conventional batch heat treatment apparatuses, the heat treatment is carried out by carrying in a reaction vessel surrounded by heaters, a holder in which a large number of wafers are stacked in a rack shape. However, since the wafer is heated by the heater arranged on the side of the reaction tube, a large temperature gradient is generated between the central portion and the peripheral portion of the wafer when the wafer is heated rapidly. A large difference occurs in the thermal budget between the wafer that first enters the reaction tube and the wafer that finally enters the reaction tube, and it is difficult to perform a process with a uniform thermal budget even in the same batch.

Under the circumstances described above, the present inventor is studying a single-wafer type heat treatment apparatus capable of rapidly heating a wafer to a predetermined heat treatment temperature and improving in-plane temperature uniformity. FIG. 11 shows an example thereof, and this heat treatment apparatus has a processing chamber 1 in which a wafer loading port 11 and a wafer loading port 12 are formed in the center of the left and right side walls, respectively, and the processing chamber 1 can be raised and lowered freely. A section 13 is provided. A planar heating source 14 including a resistance heating wire and the like is arranged outside the processing chamber 1 via a soaking member 14a. Further, a gas supply unit 15 and an exhaust unit 16 are provided at the upper and lower parts of the processing chamber 1, respectively. When heat-treating the wafer W, the planar heating source 1
4 is heated so that the wafer W reaches a set temperature, while the wafer W is loaded by the transfer arm (not shown).
Then, the wafer W is rapidly heated to a predetermined heat treatment temperature by the radiant heat of the planar heating source 14. Then, for example, an oxide film is formed on the wafer W by the processing gas from the gas supply unit 15, and the wafer W after the heat treatment is carried out to the outside through the carry-out port 12 by a carrying arm (not shown).

[0005]

According to the above-mentioned device,
The wafer W is held in the holding unit 13 in the processing chamber 1 through the loading port 11.
When the wafer W is transferred to the wafer W, the planar heating source 14 heats the soaking member, and the radiant heat from the heating member heats the wafer W rapidly. On the other hand, since the peripheral portion of the wafer W has a larger amount of heat radiation than the central portion, when the amount of heat of the wafer W increases rapidly, a large temperature difference occurs between the peripheral portion and the central portion, and the temperature rises as it is. The wafer tries to stabilize at the heat treatment temperature. However, if there is such a large temperature difference, it takes a long time for the entire wafer to stabilize at a uniform heat treatment temperature, and heat treatment with high in-plane uniformity, for example, formation of an oxide film is performed. I can't.

The present invention has been made under such circumstances, and an object thereof is to perform heat treatment with high in-plane uniformity when rapidly heating a planar object to a heat treatment temperature. It is to provide a heat treatment apparatus and a heat treatment method that can be performed.

[0007]

According to a first aspect of the present invention, there is provided a method of rapidly heating a planar object to be heat-treated to a predetermined heat treatment temperature by a heating source, wherein the object is heated by a heating source. It is characterized in that it is preheated before being exposed to.

According to the second aspect of the present invention, the planar object to be processed is transferred from the standby position to the object to be processed holding portion by the transfer means, and the object to be processed is rapidly heated to a predetermined heat treatment temperature by the radiant heat of the heating means. In the method for heat treatment by heat treatment, the method comprises the steps of preheating the object to be processed by a preheating source provided in the transfer means, and delivering the object to the object holding part from the transfer means. To do.

According to the third aspect of the present invention, the planar object to be processed is transferred by the transfer means from the standby position to the object holding part in the processing chamber, and the object to be processed is heated to a predetermined heat treatment temperature by the radiant heat of the heating means. An apparatus for rapid heating and heat treatment is characterized by comprising a preheating source for preheating the object to be processed before exposing it to the heating atmosphere of the heating source.

According to a fourth aspect of the invention, in the invention according to the third aspect, the preheating source is provided in the conveying means.

A fifth aspect of the present invention is characterized in that, in the third or fourth aspect of the present invention, the conveying means includes a cooling means for cooling the object to be processed.

According to a sixth aspect of the present invention, in the invention according to the fourth or fifth aspect, the conveying means includes a temperature adjusting body provided so as to face at least the surface to be processed of the object to be processed. The preheating source is constituted by

According to a seventh aspect of the invention, in the invention according to the sixth aspect, the temperature controller also serves as cooling means.

The invention of claim 8 is characterized in that, in the invention of claim 6 or 7, the temperature control body has a fluid passage portion inside, and a fluid for temperature adjustment is passed through this fluid passage portion. And

The invention of claim 9 is the invention of claim 6, 7 or 8.
In the invention described above, a surface of the temperature control body facing the object to be processed is characterized in that the surface is inclined so as to separate from the object to be processed from the peripheral portion toward the center.

According to a tenth aspect of the invention, in the invention according to the sixth, seventh, eighth or ninth aspect, the temperature control body is made of a light transmissive material so that a part of the radiant heat from the heating means is transmitted to the side of the object to be treated. It is characterized by being composed of.

According to an eleventh aspect of the present invention, the planar object is held in the object-holding portion in the processing chamber, and the processing gas is applied to the planar object while heating the object to a predetermined temperature. In an apparatus for supplying heat to a processing surface and performing heat treatment, a gas introducing unit is provided in the processing chamber so as to face a surface to be processed of an object to be processed held by an object holding unit, and a gas is injected from the gas introducing unit. The outlet is formed in a trumpet shape.

According to a twelfth aspect of the invention, in the invention according to the eleventh aspect, the gas introducing portion is made of a light-transmissive material.

The invention of claim 13 is the same as claim 11 or 1.
In the invention described in 2, the object-to-be-processed holding portion is configured to be movable toward and away from the gas introducing portion.

[0020]

When the object to be processed is exposed to the rapid heating atmosphere, the temperature of the object to be processed rises at a high speed, but the degree of heat radiation of the object to be processed is larger in the peripheral portion than in the central portion. There is a temperature gradient between and. Then, the object to be processed heats up at high speed while the temperature gradient is generated. Here, the difference in the degree of heat radiation between the peripheral portion and the central portion, that is, the temperature gradient, increases as the amount of heat of the object to be processed increases more. Therefore, if the object to be processed is preheated, the change in the amount of heat of the object to be processed when exposed to the rapid heating atmosphere becomes smaller accordingly, so the temperature gradient becomes gentle, and the temperature unstable region near the heat treatment temperature is reduced. It becomes shorter and the entire surface of the object to be processed is quickly stabilized at the heat treatment temperature.

Further, if the heated fluid is passed through the temperature control body of the conveying means of the object to be treated and the object is preheated by this heat, the object to be treated can be heated until it is placed in the rapid heating atmosphere. The temperature of the object to be processed is stable and the in-plane uniformity is high.If the object to be processed can be preheated and cooled by the temperature controller provided in the transfer means, the object to be processed after the heat treatment is forcibly cooled. Throughput can be improved. Furthermore, by inclining the surface of the temperature control body on the side of the object to be processed, the distance between the temperature control element and the object to be processed becomes shorter on the peripheral edge side than on the central part, so that the object to be processed is evenly reserved. Can be heated.

Further, if the gas ejection port of the gas introducing portion is formed in a trumpet shape, a flow of the processing gas from the central portion to the peripheral portion is formed along the surface of the object to be processed, so that the object to be processed is uniformly distributed. A processing gas can be supplied.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram of a heat treatment apparatus according to an embodiment of the present invention. Reference numeral 2 in FIG. 1 denotes a processing chamber made of high-purity transparent quartz. The processing chamber 2 has openings 21 and 22 for loading and unloading a wafer W, which is an object to be processed, on its side portions, and the openings 21 and 22. The upper side and the lower side of each are formed in a trumpet shape that expands toward the center. A heating source 23 formed of a resistance heating wire such as molybdenum disilicide or Kanthal (trade name) is provided on the upper and lower portions outside the processing chamber 2, and a heat insulator 24 such as alumina is provided outside the heating source 23. A water cooling jacket 25 is provided.

The first and second transfer chambers 3A and 3B are provided outside the side of the processing chamber 2 through the openings 21 and 22, respectively.
The transfer chambers 3A and 3B are shut off from the heat and gas atmosphere with respect to the processing chamber 2 by the heat shutoff valve 31 and the gas shutoff valve 32. These valves 31 and 32 are fluid pistons 31 respectively.
a, 32a. Reference numeral 33 is a seal member, and 34 and 35 are inert gas supply ports (inert gas discharge ports are not shown).

In the transfer chambers 3A and 3B, there are provided transfer means 4 which are driven to move back and forth between the transfer chambers 3A and 3B by a fluid cylinder 41 and a wafer holding portion in the processing chamber 2 which will be described later. . As shown in FIGS. 2 to 4, the carrier means 4 faces both sides of the wafer W and is fixed to the piston 42 of the fluid cylinder 41 via the fixing portion 43.
1 and 52, and is configured to hold the wafer W on the lower temperature control body 52 via the protrusions 44. Further, in the lower temperature adjusting body 52, a notch 52a having a width wider than the diameter of the elevating shaft of the wafer holder is formed so that the wafer can be transferred to a wafer holder described later in the processing chamber 2. ing. In this embodiment, these temperature control members 51 and 52 are made of metal such as stainless steel or aluminum, and a flow passage 53 (for simplification of explanation) is used to flow a temperature control fluid, for example, gas therein. 3 is used in a bent or labyrinth shape (not shown) as shown in FIG. Wafer W by preheating and passing cooling fluid
The preheating source and the cooling means are also used so as to be able to cool. However, the temperature control members 51 and 52 may be made of a light-transmissive material having high heat resistance, for example, quartz as described later.

A fluid supply pipe 54 (the same reference numeral is used for simplification of description) and a fluid discharge pipe 55 are connected to the flow passage 53, and the fluid supply pipe 54 and the fluid discharge pipe 55 are connected to each other. The outer ends penetrate the side walls of the transfer chamber 3A (3B) and are connected to the flexible tubes 56 and 57, respectively. Note that reference numerals 40a, 40b and 40c in the figure are bellows. As shown in FIG. 5, the heating fluid and the cooling fluid are heated and cooled to a predetermined temperature by a heating unit 58 and a cooling unit 59, respectively, and are circulated between the temperature control body 51 (52) and valves V1 to V4. By switching the
The fluid flowing in (52) switches between heating fluid and cooling fluid. Further, as shown in FIG. 2, a temperature sensor 60 including, for example, a thermocouple is provided in the temperature control bodies 51 and 52, and the heating unit 58 and the cooling unit 59 are controlled based on the temperature detection value of the temperature sensor 60. , By this, temperature controller 5
1, 52 are adjusted to a predetermined temperature.

A gas supply pipe 71 for supplying a processing gas is connected to the upper part of the processing chamber 2. A wafer holder 72 is provided in the processing chamber 2 so as to face the gas supply pipe 71, and the wafer holder 72 is provided.
Is provided on the elevating shaft 74 that is elevated by the elevating means 73 outside the processing chamber 2. 73a is a rotating mechanism for rotating the elevating shaft 74. An exhaust pipe 76 is connected to a pipe portion 75 surrounding the elevating shaft 74 in the lower portion of the processing chamber 2. Reference numeral 77 is a water cooling jacket, and 78 is a gas supply pipe for forming a flow curtain of an inert gas.

Next, the operation of the above embodiment will be described. First, an object to be processed, for example, a wafer W is transferred from a load lock chamber (not shown) to the transfer means 4 in the first transfer chamber 3A. In this embodiment, the transfer means 4 (more specifically, the position on the protrusion 44) in the transfer chamber 3A corresponds to the standby position for the wafer W. A heating fluid source 58 is provided in the temperature control bodies 51 and 52 of the transport means 4.
A more heated fluid, for example, a gas is passed therethrough, whereby the temperature control bodies 51 and 52 are heated. Therefore, the temperature of the wafer W rises, and when the temperature of the wafer W reaches, for example, 200 to 400 ° C., the heat cutoff valve 31 and the gas cutoff valve 32 are opened to allow the transfer means 4 to enter the processing chamber 2, and the wafer holding portion 72 to hold the wafer. Hand over W. This transfer is performed by the temperature controller 52 at the bottom.
The vertical axis 73 of the wafer holding part 72 standing by at a position lower than the wafer W is inserted into the notch 52a, and the vertical axis 73 is raised. Further, the wafer W is preheated by the temperature controllers 51 and 52 of the transfer means 4 and continues to rise in temperature, and when the temperature reaches, for example, 400 to 600 ° C., the transfer means 4 returns to the inside of the transfer chamber 3A and the heat cutoff valve 31 and the gas. The shutoff valve 31 is closed. On the other hand, the heating source 23 (resistance heating wire) is power-controlled so as to reach a predetermined temperature, and when the transfer means 4 is retracted, the wafer W is exposed to the heating atmosphere from the heating source 23 and receives radiant heat, which causes rapid heating. Then, the temperature is raised to 1200 ° C., for example. Then, a predetermined processing gas is supplied into the processing chamber 2 through the processing gas supply pipe 71 to form an oxide film on the wafer W.

After that, the transfer means 4 enters the processing chamber 2 from the second transfer chamber 3B and is transferred to the transfer means 4 from the wafer holder 72 by the operation reverse to the above, and the transfer means 4 is transferred to the second transfer chamber. Evacuate into the transfer chamber 3B. A cooling fluid flows in the temperature control bodies 51 and 52 of the transfer means 4, and the wafer W
Are cooled when delivered to the transport means 4. Further, the wafer W transferred into the second transfer chamber 3B is carried into the atmosphere through a load lock chamber (not shown), but an undesired natural oxide film is formed when the wafer W is exposed to the atmosphere at a high temperature. It is necessary to carry out W into the atmosphere in a state of being cooled to some extent. Therefore, by providing cooling means (the temperature controllers 51 and 52 in this example) on the transfer means 4 and forcibly cooling the wafer, the throughput is improved, and it is not necessary to separately provide a cooling plate or the like.

According to the above-mentioned embodiment, as shown in FIG. 6, the wafer is preheated by the temperature control bodies 51 and 52 from the time t ₁ when it is transferred to the transfer means 4 of the first transfer chamber 3A, and then the predetermined temperature is maintained. At time t ₂ when the temperature T _S reaches, for example, 400 to 600 ° C., the transport means 4 retracts toward the first transport chamber 3A. By the way, when the wafer is exposed to the rapid heating atmosphere by the heating source 23, the temperature rises at a high speed, but the degree of heat radiation at the peripheral portion of the wafer is larger than that at the central portion, and the temperature of the wafer rises with a temperature gradient between them. It will be.

The difference in the degree of heat radiation between the peripheral portion and the central portion of the wafer, that is, the temperature gradient, is so large that the heat quantity of the wafer increases sharply. Therefore, if the wafer is preheated, it is exposed to a rapid heating atmosphere. Since the change in the heat quantity of the wafer becomes smaller accordingly, the temperature gradient becomes gentle. Here, there is a temperature unstable region from the temperature near the heat treatment temperature to the stabilization of the heat treatment temperature. If this temperature unstable region exists, the wafer receives a large thermal budget, and its influence varies within the surface. For example, the in-plane uniformity of the film thickness of the oxide film becomes low. Therefore, if the temperature gradient in the wafer surface is small, the temperature unstable region is short and the in-plane temperature nonuniformity in the temperature unstable region is small,
Since the heat treatment temperature is quickly stabilized, the in-plane uniformity of the film thickness is improved.

The preheating source for preheating the wafer may be provided, for example, in the first transfer chamber 3A instead of being provided in the transfer means 4, but if the transfer means 4 is provided with preheating, the wafer is preheated. Since the wafer does not cool during the transfer of the wafer and during the transfer to the wafer holder 72, the wafer can be preheated to a high temperature that is not affected by the thermal budget. The higher the preheating temperature is, the more unstable the temperature becomes. It is very effective because the area becomes short. When the wafer is preheated or cooled, if the heating fluid or the cooling fluid is allowed to flow through the temperature control bodies 51 and 52, the temperature control is easy and the temperature can be rapidly adjusted. It should be noted that the temperature control bodies 51 and 52 may have a structure in which, for example, an inert gas for temperature control (for heating or cooling) is blown onto the wafer instead of the structure for allowing the temperature control fluid to flow inside. A lamp or the like may be incorporated in the temperature control bodies 51 and 52 to preheat the wafer W by radiant heat. When the wafer W is transferred from the first transfer chamber 3A to the holding unit 72 in the processing chamber 2, the wafer W is lifted and lowered in the transfer chamber 3A in the same manner as the holding unit 72.
A rotatable holding unit (not shown) is provided, the wafer W on the holding unit is covered by the transfer unit 4, the wafer W is rotated 90 degrees by the holding unit, and then the wafer W is transferred by the transfer unit 4. Is transferred to the wafer holder 72 in the processing chamber 2 and the wafer W is rotated 90 degrees while the transfer means 4 covers the wafer W.
It is possible to mitigate the non-uniformity in how the heat is received by a.

The temperature control elements 51 and 52 are made of a light-transmissive material, for example, quartz, and as a result, in addition to preheating by the heat of the temperature control fluid, a heating source that transmits the temperature control elements 51 and 52. The wafer may be preheated by the radiant heat 23. In this case, the quartz forming the temperature control elements 51 and 52 may be set to have an appropriate transparency by using, for example, bubbles. Furthermore, as shown in FIG. 7, the surfaces 61 and 62 of the temperature control bodies 51 and 52 facing the wafer W are inclined so as to be separated from the wafer W from the peripheral portion toward the central portion,
That is, it may be formed in a notch shape in a conical shape. In this case, since the wafer W has a larger amount of heat entering and exiting the peripheral portion than the central portion, for example, the degree of heat dissipation is large, the temperature control is performed in this manner. If the surfaces of the bodies 51 and 52 facing the wafer W are inclined, the temperature adjusting body 5 is moved toward the periphery of the wafer W.
Since the distance from the wafers 1, 52 is shortened, the wafer W can be preheated or cooled with high uniformity.

The structure shown in FIG. 8 may be adopted as a method for introducing the processing gas into the processing chamber 2. That is, a gas introducing portion 8 for introducing the processing gas is provided in the processing chamber 2 so as to project from the top side. This gas introduction part 8
Has a base end portion connected to a gas flow path formed in the upper wall portion of the processing chamber 2, and a jet port formed in a trumpet shape that widens downward. It is made of a transparent material such as quartz.

By configuring the gas introduction section in this way, the processing gas can be supplied to the surface of the wafer W with high in-plane uniformity. The reason for this is that, when the processing gas is supplied from the top of the processing chamber 2 as shown in FIG. 9 (the previous embodiment), the processing gas flows from the gas supply pipe 71 along the inner surface of the wall, so that the central portion While the flow velocity from the bottom to the bottom decreases, the temperature of the gas is slightly lower than the temperature of the wafer W, so that the gas heated near the surface of the wafer W rises and causes convection. This is because in the configuration, the processing gas flows so as to spread from the central portion of the wafer W to the peripheral edge thereof as shown in FIG. 10, and convection hardly occurs. In this case, since the optimum distance between the gas introducing unit 8 and the wafer W varies depending on the heat treatment temperature, the flow rate of the processing gas, etc., it is desirable that the height of the wafer holding unit 72 can be adjusted by raising and lowering the raising and lowering shaft 74.

[0036]

As described above, according to the present invention, when the object to be processed is rapidly heated to the heat treatment temperature and heat-treated, heat treatment with high in-plane uniformity can be performed.

[Brief description of drawings]

FIG. 1 is a sectional view showing an overall configuration of a heat treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a side view showing a wafer transfer unit.

FIG. 3 is a plan view showing a wafer transfer unit.

FIG. 4 is a perspective view showing a wafer transfer unit.

FIG. 5 is an explanatory diagram showing a temperature control gas piping system of a wafer transfer unit.

FIG. 6 is a characteristic diagram showing a temperature change of the wafer until the heat treatment after the wafer is transferred to the transfer means.

FIG. 7 is a side view showing another example of a wafer transfer unit.

FIG. 8 is a cross-sectional view showing an example of a gas introduction unit that supplies a processing gas.

9 is an explanatory diagram showing a flow of a processing gas in the embodiment shown in FIG.

10 is an explanatory diagram showing a flow of a processing gas when the gas introduction part shown in FIG. 8 is used.

FIG. 11 is a sectional view showing a comparative example of a heat treatment apparatus.

[Explanation of symbols]

 2 processing chamber 23 heating source 3A, 3B transfer chamber 4 transfer means 42 pistons 51, 52 temperature control body 53 temperature control gas flow passage 54 temperature control gas supply pipe 58 heating fluid source 59 cooling fluid source 71 gas introduction pipe 72 Wafer holding part 8 Gas introduction part W Semiconductor wafer

Claims (13)

[Claims] 1. A method for heat-treating a planar object to be heat-treated by a heating source to a predetermined heat treatment temperature, wherein the object is preheated before being exposed to a heating atmosphere by the heating source. Characterizing heat treatment method. 2. A method for carrying out a heat treatment by carrying a planar object to be processed from a standby position to an object holding part by a carrying means and rapidly heating the object to a predetermined heat treatment temperature by radiant heat of a heating means. A heat treatment method, comprising: a step of preheating the object to be processed by a preheating source provided in the carrying means; and a step of delivering the object to the object holding part from the carrying means. 3. A planar object to be processed is transferred by a transfer means from a standby position to an object holding part in a processing chamber, and the object is rapidly heated to a predetermined heat treatment temperature by radiant heat of a heating means to perform heat treatment. The heat treatment apparatus according to claim 1, further comprising a preheating source for preheating the object to be processed before exposing the object to be heated to a heating atmosphere of the heating source. 4. The heat treatment apparatus according to claim 3, wherein the preheating source is provided in the conveying means. 5. The heat treatment apparatus according to claim 3, wherein the transport means includes a cooling means for cooling the object to be processed. 6. The transporting means comprises a temperature adjusting body provided so as to face at least the surface to be processed of the object to be processed, and the temperature adjusting body constitutes a preliminary heating source. Item 6. A heat treatment apparatus according to item 4 or 5. 7. The heat treatment apparatus according to claim 6, wherein the temperature controller also serves as a cooling means. 8. The heat treatment apparatus according to claim 6, wherein the temperature control body has a fluid flow passage therein, and a fluid for temperature control is passed through the fluid flow passage. 9. The surface of the temperature control body facing the object to be processed is inclined so as to separate from the object to be processed from the peripheral portion toward the center. Heat treatment equipment. 10. The temperature control body is made of a light-transmissive material so that a part of the radiant heat from the heating means is transmitted to the side of the object to be treated.
The heat treatment apparatus described. 11. A planar object to be processed is held in a target object holding section in a processing chamber, and a processing gas is supplied to a surface to be processed of the planar object while heating the object to a predetermined temperature. In the apparatus for heat treatment, a gas introducing part is provided in the processing chamber so as to face the surface to be processed of the object held by the object holding part, and the gas outlet of the gas introducing part is shaped like a trumpet. A heat treatment apparatus characterized by being formed. 12. The heat treatment apparatus according to claim 11, wherein the gas introduction part is made of a light-transmissive material. 13. The heat treatment apparatus according to claim 11, wherein the object-to-be-processed holding portion is configured to be movable toward and away from the gas introduction portion.