WO1994018695A1

WO1994018695A1 - Apparatus for heat treatment

Info

Publication number: WO1994018695A1
Application number: PCT/JP1993/000146
Authority: WO
Inventors: Mitsusuke Kyogoku
Original assignee: Asm Japan K.K.
Priority date: 1993-02-05
Filing date: 1993-02-05
Publication date: 1994-08-18

Abstract

An apparatus for heat treatment, which prevents metallic contamination of the object of heat treatment due to a metallic manifold, and which reliably maintains a hermetic separation state between a moving mechanism storage chamber and a reaction chamber even when the pressure inside the former is remarkably lower than the pressure inside the latter. An exhaust port (7) is disposed in the quartz reaction chamber (1) so as to evacuate the inside of this chamber (1), and a sealing flange of a double structure is formed of a quartz flange (9) and a metallic flange (10). When the reaction chamber is under a sealed state, the metallic flange (1) is not exposed to the reaction chamber (1). Further, the sealing flange and a moving body (12) are engaged with each other by springs (3). When the sealing flange (10) is placed in the sealing position, the springs energized by the moving body press the sealing flange against the internal pressure of the reaction chamber.

Description

Specification

Heat treatment equipment

Technical field

The present invention relates to a semiconductor manufacturing apparatus, particularly to an oxidation / diffusion apparatus.

Background art

Figures 1a and 1b and Figures 2a and 2b show a conventional vertical heat treatment apparatus and a conventional load-lock heat treatment apparatus that perform the oxidation and diffusion processes at normal pressure.

A heating element (2) is provided around the reaction chamber (1) made of high-purity material such as quartz, and one open end of the reaction chamber (1) is moved by a moving mechanism (not shown). Sealed by a sealed flange. The moving body and the seal flange, which are moved by the moving mechanism, are connected by a panel body to improve the sealing between the seal flange and the reaction chamber. Since the pressure inside the reaction chamber and the external pressure during the process are almost the same, it is sufficient for the panel body to have a repulsive force enough to lightly press the sealing flange through the sealing material in the reaction chamber. The seal flange is composed of a quartz flange (9) and a metal flange (10). When the reaction chamber is sealed, only the quartz flange is exposed inside the chamber. The reaction chamber (1) is provided with a gas inlet (6), which runs along the outer side wall of the chamber to one closed end of the reaction chamber, from which the gas enters the chamber. Is introduced. A gas exhaust port (7) is provided at one open end of the reaction chamber 1 from which gas is exhausted. A boat (3) and a boat table (5) holding a plurality of heat-treated bodies (4) in a stacked state are provided on the seal flange. Insertion and removal are performed inside the member.

When the boat is taken out of the reaction chamber (1) by the moving mechanism (Fig. 1b), the object to be heat-treated is set on the boat. The moving mechanism moves the boat into the reaction chamber, seals the flange, and seals the inside of the reaction chamber. An inert gas such as nitrogen gas is introduced from the gas inlet, and purges air components that enter during the movement of the boat into the chamber. When the object to be heat-treated reaches a predetermined temperature by the heating element, a predetermined process gas is introduced. In the dry oxidation process, oxygen and the like are generated, and in the wet oxidation process, steam and the like generated by burning oxygen and hydrogen in an external combustion device (not shown) provided in front of the inlet (6). In the phosphorus diffusion process, phosphorus oxychloride (POCl ₃ ) or the like is introduced. The inner diameter of the inlet is usually from 10 mm to 20 mm. The exhaust port (7) is open to the atmospheric pressure atmosphere, and the introduced gas is discharged from the exhaust port so as to be pushed out after contributing to a predetermined reaction. The inner diameter of the exhaust port is usually several 10 mm to 20 several mm, and is often larger than the inner diameter of the inlet. After the end of the process, the introduction of the process gas is stopped, and after purging with nitrogen gas or the like again, the boat is taken out of the reaction chamber by the moving mechanism.

In recent years, with the increasing integration of semiconductor devices, a load-lock type heat treatment device has been devised to prevent unexpected oxidation caused by atmospheric components (oxygen, water vapor, etc.) and process gas remaining in the reaction chamber after the process. It has been. Figures 2a and 2b show examples. A moving mechanism composed of a ball screw (13), a moving body (12) and the like is placed inside the moving mechanism housing chamber (11) for sealing from the atmosphere. The moving mechanism storage chamber 1 (11) has an exhaust port (15) for evacuating the inside. When the process is performed at normal pressure, the internal pressure of the reaction chamber The force between the seal flange and the moving body (12) is not a panel, but a rigid body, instead of a panel. After evacuation, high-purity nitrogen gas is introduced to keep the internal pressure of the transfer mechanism storage chamber 1 (11) at about normal pressure. An opening (14) for inserting and taking out the object to be heat-treated is provided in the moving mechanism housing chamber (11), and is connected to the front chamber (17) via a gate valve (16). The front room houses a transfer mechanism for inserting and removing the object to be heat-treated from the opening into the boat. A metal manifold (23) having an exhaust port (7b) is connected to the reaction chamber 1 to evacuate the inside of the reaction chamber made of high-purity material such as quartz, and the manifold is cooled. (23b). After the process is completed, the inside of the boat is evacuated to about 10 to ⁶ Torr by a vacuum exhaust device connected to the exhaust port (7b), and then the boat is unloaded to take out the object to be heat-treated.

In a load-lock type heat treatment apparatus devised to realize processing of a more highly integrated device, a metal manifold is provided to evacuate the inside of the reaction chamber. This causes heavy metal contamination of the object to be heat-treated, fighting this point, and deteriorating the performance of the equipment. Since the oxidation process is usually performed at a high temperature of around 100,000, the effect of the radiant heat is significant. Even if a cooling unit is provided, it is inevitable that metal contamination becomes significantly larger than in a conventional oxidation diffusion apparatus in which the entire inner surface of the reaction chamber is made of quartz. If the cooling is excessive, water vapor or the like will be condensed on the inner surface of the manifold during wet oxidation, causing even more serious problems such as metal corrosion. In addition, the radiating heat from the lower part of the heating element increases due to the cooling, and the heat equalizing characteristic of the heating element deteriorates. If the transfer mechanism storage chamber is filled with high-purity nitrogen after evacuation, the cleanliness of the atmosphere in the apparatus has a limit depending on the purity of the supplied nitrogen gas and the cleanliness of the gas supply system. In order to meet the demand for devices with higher integration, the pressure in the transfer mechanism storage chamber should be constantly reduced to a high vacuum atmosphere of 10 to ⁷ Torr or less in order to further reduce the concentration of residual oxygen and water vapor. Need to be kept. During the process performed under normal pressure, the atmosphere in the moving mechanism storage chamber was set to normal pressure with nitrogen gas, and the system was evacuated after the process was completed. Cost of high-purity nitrogen gas increases. If the moving body and the seal flange are connected by a rigid body, the precision of the stopping position of the moving body and the parallelism between the seal flange and the mating surface must be strictly controlled, increasing the manufacturing cost and increasing the reaction. There is also the problem that re-assembly after chamber maintenance requires a great deal of skill.

Disclosure of the invention

An exhaust port for evacuating the inside of the reaction chamber is provided in the reaction chamber, and the seal flange has a double structure of a quartz flange and a metal flange, and when the metal flange is at the movement limit position, The seal is formed between the reaction chamber and the quartz flange via a seal material.

In addition, the size of the repulsive force generated by moving the moving body after the seal flange moves to the sealing position by connecting the seal flange and the moving body with the panel body When the pressure in the storage chamber is vacuum and the pressure in the reaction chamber is normal pressure, the moving body is moved and stopped so that the force applied to the seal flange from one side of the reaction chamber is equal to or greater than the pressure applied. BRIEF DESCRIPTION OF THE FIGURES

Figure 1a shows a conventional heat treatment apparatus.

Figure lb shows a conventional vertical heat treatment apparatus with the boat table taken out of the reaction chamber.

Fig. 2a shows a conventional load-lock type ripening device.

Figure 2b shows a conventional load-lock type heat treatment apparatus with the boat table taken out of the reaction chamber.

FIG. 3 is an overall view of an apparatus showing the present invention.

FIG. 4a is a partially enlarged view of the device shown in FIG.

FIG. 4b is a partially enlarged view of the device shown in FIG.

FIG. 4c is a partially enlarged view of another embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 3 is an overall view of an apparatus showing one embodiment of the present invention. FIG. 4a is a partially enlarged view of FIG.

An exhaust port (7) for evacuating the inside of the reaction chamber (1) is provided. The inner diameter of the exhaust port (7) needs to be at least about 50 mm or more in order to make a high vacuum inside the reaction chamber in a short time. In our equipment, the inner diameter of the reaction chamber is 240 mm, and the inner diameter of the exhaust port is 100 Omm. It may be provided separately, or may be branched at the end of the exhaust port (7). A heat insulating material (8) is attached around the reaction chamber around the exhaust port (7) to prevent heat from escaping from this part, improve the uniformity of the heating element, and reduce the temperature inside the reaction chamber. © Tsu DOO steam during the oxidation process is maintained at a temperature of not condensation inside _D

The quartz flange (9) on which the boat (3) and the boat table (5) are placed It is placed on a metal flange (10) and moved by a moving mechanism. When the boat (3) reaches a predetermined position in the reaction chamber (1), the shoulder of the metal flange (10) comes into contact with the shoulder (11) of the moving mechanism storage chamber and cannot move any further. At this time, there is a slight gap between the quartz flange (9) and the end of the reaction chamber (1), and it is configured to seal with a sealing material (18) made of fluorine rubber or the like. . Therefore, there is no danger that the quartz will collide with each other or that no extra force will be applied to the quartz parts, causing the quartz to break. Assuming that the dimension between the moving body (12) and the metal flange (10) at this time is "A", the moving body (12) is further moved to become the dimension "B". According to Fig. 4b, the repulsive force of the panel body, which is the product of the panel constant of panel body (30) and the amount of compression "A-B", shows that the metal flange (10) is the moving mechanism storage chamber (11). Is pressed against the shoulder. In this state, a normal pressure process is performed in the reaction chamber while the transfer mechanism storage chamber 1 is kept at a vacuum. At this time, a force having a magnitude obtained by multiplying the pressure difference between the two chambers by the area within the effective diameter of the seal member (18) is applied to the seal flange from one side of the mobile device oval storage chamber. The spring constant of the panel body and the amount of compression “A-B” are determined so that the repulsive force of the spring body is greater than the magnitude of this force. Even if a force due to the pressure difference is applied from above, the metal flange (10) acts as reinforcement against the quartz flange (9), so that the quartz flange (9) is not damaged. In the case of (10), since the force applied from the one side of the mobile machine fine storage chamber is greater than the force applied from the lower side by the spring body, it is not moved downward. The flange at the end of the reaction chamber (1) is mounted on the moving mechanism storage chamber (11) via a seal material (19a) and a buffer material (21a). A fixed flange (20) having a cooling part (20b>) And is fixed via the cushioning material (21b). The cooling section may be provided on the moving mechanism storage chamber side.

FIG. 4c is a partially enlarged view showing another embodiment. The reaction chamber 1 (1) is formed in a tubular shape to the lower side from the flange portion, the inner diameter is widened near the end portion, and the end portion is sealed. This refracts the heat energy transmitted by the light beam inside the transparent quartz and reduces the effect of heat on the seal material (18). The flange portion of the first reaction chamber (1) is fixed on a flange (22) having a cooling means (22b), and the flange (22) is fixed on a moving mechanism housing chamber (11).

Claims

The scope of the claims

A reaction chamber made of high-purity material such as quartz, a heating device arranged around the reaction chamber, and a moving mechanism for inserting and removing the boat holding the object to be heat-treated from the reaction chamber In a load-lock type heat treatment apparatus comprising a moving mechanism storage chamber for shielding and isolating the moving mechanism from the atmosphere,

A seal flange separating the reaction chamber and the moving mechanism storage chamber is driven by the moving mechanism,

The seal flange has a double structure including a flange portion made of a high-purity material such as quartz and a flange portion made of a metal material. When the metal flange is at the movement limit position, the quartz flange portion and one end of the reaction chamber are opened. Part is sealed via the sealing material,

After the seal flange and the moving body that is moved by the moving mechanism are connected by a spring body, the magnitude of the repulsive force of the panel body generated by the movement of the moving body after the seal flange moves to the movement limit position depends on the process. During the process, the moving body must be stopped and held at that position during the process, which is larger than the force for pushing open the flange generated when the process pressure in the reaction chamber is larger than the pressure in the reaction chamber. A load lock type heat treatment apparatus characterized by the above-mentioned. 2. The apparatus according to claim 1, wherein an exhaust port for evacuating the inside of the reaction chamber is provided in the reaction chamber partition wall.

3. The apparatus according to claim 2, wherein the exhaust port is provided between the heating device and a moving mechanism storage chamber.

The inner diameter of the exhaust port is 50 mm or more. Item 3. The heat treatment apparatus according to item 2 or 3.

. The reaction chamber first internal to the exhaust system for evacuating, Mature processing apparatus according to claim 2 or 3, wherein it has a function of controlling the chamber Ichi圧force 1 0 ³ Torr in the range of 1 0 Torr .