JP2000353665A - Substrate processing equipment - Google Patents

Abstract

(57) [Summary] In a high-temperature processing of a wafer, a wafer is uniformly formed into a film, and a uniform and high-quality film-formed wafer is manufactured with a high yield. A boat on which a substrate is loaded is rotatably supported, a rotation support portion is hermetically sealed, and the rotation support portion is air-cooled by a cooling gas.
Provide bearings that can be used under reduced pressure and high temperature,
During the high-temperature process in the reaction tube, the boat is rotated to uniformly form a film on the wafer, thereby improving the quality and the yield.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a substrate processing apparatus such as a vertical diffusion semiconductor manufacturing apparatus having a vacuum chamber.

[0002]

2. Description of the Related Art A vertical diffusion semiconductor manufacturing apparatus having a vacuum chamber as one of substrate processing apparatuses will be described with reference to FIG.

A reaction tube 3 is provided above the vacuum chamber 1 in an airtight manner in the vacuum chamber 1, and a heater 4 is provided around the reaction tube 3.
The inside is heated.

A movable part 5 also serving as a furnace lid is supported in the vacuum chamber 1 by a lifting mechanism (not shown) so as to be able to move up and down. A boat 6 stands on the movable part 5.

A door valve 8 is provided on the side of the vacuum chamber 1.
Are openably and closably provided in an airtight manner. A wafer transfer machine 9 is disposed opposite the boat 6 with the door valve 8 interposed therebetween, and the wafers 10 are loaded into the lowered boat 6 in a horizontal posture in multiple stages by the wafer transfer machine 9. ing.

[0006] The wafer 10 is loaded into the boat 6 in multiple stages through the door valve 8 by the wafer transfer machine 9. The boat 6 is lifted by a lifting mechanism (not shown) together with the movable part 5, and the boat 6 is charged into the reaction tube 3,
The reaction tube 3 is hermetically closed by the movable part 5.

The reaction tube 3 is heated by a heater 4 and is evacuated by a vacuum pump (not shown) while a reaction gas is supplied into the reaction tube 3 by a reaction gas supply tube (not shown). By such a high temperature process, a required film is formed on the surface of the wafer 10.

[0008]

The temperature in the reaction tube 3 varies depending on the type of the film forming process, and reaches about 1000 ° C. in the high-temperature process process. The temperature distribution inside the reaction tube 3 is not always uniform. Further, the concentration distribution of the reaction gas in the reaction tube 3 tends to be non-uniform.

Further, since the wafers 10 are loaded in multiple stages in the boat 6, it is difficult to supply the reaction gas evenly over the entire length and the entire circumference. It is difficult to flow the reaction gas uniformly.

Therefore, the thickness of the film formed on the surface of the wafer 10 may be non-uniform, and the non-uniform film may also be generated between the wafers 10 in the boat 6. Cheap.

Therefore, a dummy wafer or the like is arranged in a range where the temperature distribution and the reaction gas distribution are likely to be non-uniform in the reaction tube 3. However, at present, among the product wafers, there may be a wafer having insufficient uniformity of film formation. It is known that rotating the boat 6 in the reaction tube 3 is effective for improving the uniformity of film formation.

However, since the temperature inside the reaction tube 3 becomes about 1000 ° C. under reduced pressure, the temperature exceeds the heat resistant temperature of the sealing material of the bearing portion of the rotating shaft. Although it is conceivable to cool the sealing material with water, since the inside of the vacuum chamber 1 also has a high temperature and is in a decompressed state, the work of arranging the cooling water pipe in the vacuum chamber 1 becomes large and the construction cost is high. Further, the sealing member is not water-cooled because there is a risk of water leakage which may be fatal in the vacuum chamber 1. Therefore, rotating the boat 6 in the reaction tube 3 during the film forming process has not yet been put to practical use in a substrate processing apparatus having the vacuum chamber 1.

In view of the above circumstances, the present invention provides a bearing portion that can be used under reduced pressure and high temperature, and rotates a boat during a high-temperature process in the reaction tube so that a wafer is rotated. Is uniformly formed into a film to improve the quality and the yield.

[0014]

SUMMARY OF THE INVENTION According to the present invention, there is provided a substrate having a structure in which a boat on which a substrate is loaded is rotatably supported, a rotary support is hermetically sealed, and the rotary support is air-cooled by a cooling gas. A boat related to a processing apparatus and supported in a vacuum chamber so as to be able to move up and down is loaded into a reaction tube, and supports the boat in a substrate processing apparatus configured to form a film on a substrate in the reaction tube. The present invention relates to a substrate processing apparatus in which a shaft is rotatably and air-tightly supported by a magnetic seal unit, and a cooling gas nozzle is provided toward the magnetic seal unit, and further, the substrate processing wherein the cooling gas is an inert gas for purging. It concerns the device.

The boat loaded with the substrate to be processed is loaded into a reaction tube, and the substrate is heated and supplied with a reaction gas to perform a high-temperature process. The substrate is uniformly formed into a film, and a processed substrate of uniform and good quality is manufactured with high yield.

Since an inert gas such as nitrogen gas is blown onto the magnetic seal unit, heat transferred from the reaction tube to the magnetic seal unit is removed by the nitrogen gas. Since the temperature rise of the magnetic seal unit is prevented, the sealing performance is maintained, and the magnetic seal unit can be used stably for a long period of time.

Since the inside of the vacuum chamber is replaced with the inert gas blown by the inert gas blown to the cooling fins,
Natural oxidation of the unprocessed substrate or the processed substrate is prevented.

Further, since the inert gas is clean, particles serving as a source of contamination of the processed substrate are discharged from the vacuum chamber by the clean inert gas flow, and the inert gas flows into a cooling step after the high temperature process. The contamination of certain processed substrates is prevented.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

An embodiment of the present invention will be described with reference to FIGS.

1 and 2, the same components as those in FIG. 3 are denoted by the same reference numerals.

A furnace port 2 is opened on the upper side of the vacuum chamber 1, and a reaction tube 3 is airtightly erected in the vacuum chamber 1 concentrically with the furnace port 2, and a flange portion 13 is provided at a lower end of the reaction tube 3.
A reaction tube O-ring 14 is sandwiched between the flange portion 13 and the upper peripheral portion of the furnace port 2 so that both are hermetically sealed.

A heat equalizing tube 15 is provided concentrically outside the reaction tube 3, and the outer periphery of the heat equalizing tube 15 is surrounded by the heater 4.

The furnace cover 1 is mounted on a movable block (both not shown) which is raised and lowered by a lifting mechanism in the vacuum chamber 1.
6 is supported, and a lid O-ring 17 is
Is disposed concentrically with the furnace port 2 and the O-ring 17 for the lid is provided.
Abuts against the lower peripheral portion of the furnace port 2 so that the furnace port 2 and the furnace cover 16 can be hermetically sealed.

The through hole 18 is formed in the furnace cover 16 with the furnace port 2.
A magnetic seal unit 20 is fixed to the lower surface of the furnace cover 16 concentrically with the through hole 18.

A bearing O-ring 22 is sandwiched between the upper end surface of the unit cylinder 21 of the magnetic seal unit 20 and the lower peripheral edge of the through hole 18 so that both are hermetically sealed. . A required number of cooling fins 23 (three in this embodiment) are provided on the outer peripheral surface of the unit cylindrical body 21.
A large-diameter rotary shaft 25 is rotatably supported in the cylindrical hole of the unit cylinder 21 by upper and lower bearings 26 and 27, and a magnetic fluid seal 29 is provided between the upper and lower bearings 26 and 27. The magnetic fluid seal 29 is disposed and held by a permanent magnet, and the large-diameter rotary shaft 25 and the unit cylinder 21 are hermetically sealed by the magnetic fluid seal 29.

The lower end of a rotary support shaft 31 is concentrically fixed to the upper end surface of the large-diameter rotary shaft 25, and the other end of the rotary support shaft 31 is inserted into the through hole 18 and projects from the through hole 18. The boat 6 is concentrically attached to the upper end of the rotation support shaft 31. The boat 6 can be loaded with silicon wafers 10 in multiple stages in a horizontal posture.

A drive casing 34 is hermetically attached to the lower end of the unit cylinder 21 via a drive O-ring 35, and a worm gear 36 is concentrically fixed to the lower end of the large-diameter rotary shaft 25. A worm 37 meshing with the worm gear 36 is fitted on a rotating shaft 39 of a motor 38. The motor 38 is housed in the drive unit casing 34 in an airtight manner.

An inert gas purge nozzle 42 is hermetically pierced through the upper portion of the side surface of the vacuum chamber 1, and the tip of the inert gas purge nozzle 42 is opened near the cooling fin 23.

An inert gas supply pipe 43 is connected to a base end of the inert gas purge nozzle 42, and the inert gas supply pipe 43 is connected to an inert gas supply source 44 such as a nitrogen gas cylinder.

An exhaust port 4 is provided at the lower side of the vacuum chamber 1.
7, an exhaust pipe 48 is connected to the exhaust port 47,
The other end of the exhaust pipe 48 is connected to a vacuum pump 49.

Hereinafter, the operation will be described.

The wafer 1 is placed on the boat 6 in the vacuum chamber 1.
After being loaded in multiple stages, the boat 6 and the furnace cap 16 are raised by an elevating mechanism (not shown), and the boat 6 is charged into the reaction tube 3. The furnace port 2 of the reaction tube 3 is
6 and the lid O-ring 17 are hermetically sealed.

The reaction tube 3 is pre-heated by a heater 4. After the boat 6 is loaded into the reaction tube 3, the pressure inside the reaction tube 3 is reduced and the reaction gas is supplied to the reaction tube 3. Is supplied.

At the same time that the furnace port 2 is closed by the furnace cover 16, a motor 38 is driven and a rotating shaft 39,
The large-diameter rotary shaft 25 is rotated via the worm 37 and the worm gear 36 sequentially.

The large-diameter rotary shaft 25 is rotatably supported at upper and lower ends by bearings 26 and 27, respectively.
The bearings 26 and 27 support the load of the rotation support shaft 31 joined to the large-diameter rotation shaft 25 and the load of the boat 6 attached to the tip of the rotation support shaft 31. The magnetic fluid seal 29 hermetically seals the space between the large-diameter rotary shaft 25 and the unit cylinder 21.

However, the atmosphere in the reaction tube 3 is about 100
The magnetic seal unit 20 heated to 0 ° C. and exposed to the atmosphere also rises in temperature by heat conduction. Since the magnetic fluid seal 29 of the magnetic seal unit 20 is very weak to heat and the sealing performance is easily deteriorated, the magnetic fluid seal 29
Temperature must be prevented.

For this purpose, for example, nitrogen gas is supplied from an inert gas supply source 44 to an inert gas supply pipe 43, and the nitrogen gas is supplied from an inert gas purge nozzle 42 to a cooling fin on the outer surface of the unit cylinder 21. 23 is sprayed.
Thus, the heat transferred to the magnetic seal unit 20 is removed from the cooling fins 23 by the nitrogen gas, thereby preventing the temperature of the magnetic seal unit 20 from rising, and the magnetic fluid seal 29 is connected to the reaction tube. 3 is protected from heat transfer.

Therefore, the magnetic sealing unit 20 can exhibit the sealing performance stably during the rotation of the large-diameter rotary shaft 25 without being thermally damaged by the heat from the reaction tube 3. Since an inert gas such as nitrogen gas is used as the cooling gas, it does not adversely affect the atmosphere in the vacuum chamber 1.

With the rotation of the large-diameter rotary shaft 25, the rotation support shaft 31 and the boat 6 are also rotated in the reaction tube 3. Each wafer 10 loaded in the boat 6 is also rotated and subjected to a high-temperature process.

At the time of the high-temperature process, the rotation of the boat 6 and the wafers 10 causes the wafers 10 to uniformly contact the reaction gas heated in the reaction tube 3. Even if there is non-uniformity, it is made uniform by rotation, so that a uniform film is formed on the surface of each wafer 10.

Thus, the wafers 10 are not only formed individually with a uniform thickness, but also between the respective wafers 10 so as to have a uniform thickness. Wafers are manufactured with good yield.

The nitrogen gas blown to the cooling fins 23 diffuses into the vacuum chamber 1. Since the inside of the vacuum chamber 1 is evacuated by the vacuum pump 49, the inside of the vacuum chamber 1 is gradually replaced with a nitrogen gas atmosphere.
By the end of the high temperature processing in the reaction tube 3, the inside of the vacuum chamber 1 is completely replaced with nitrogen gas.

The nitrogen gas is a clean gas which does not contain substances such as particles contaminating the processed substrate, and the atmosphere in the vacuum chamber 1 is evacuated by the vacuum pump 49 so that the inside of the vacuum chamber 1 is exhausted. The atmosphere is replaced by the clean nitrogen gas, and the vacuum chamber 1
Particles within are significantly reduced.

After the film formation on the wafer 10 is completed, the furnace cover 16 is lowered, and the magnetic seal unit 20, the rotary support shaft 31, and the boat 6 are also lowered integrally. It is returned into the vacuum chamber 1. Thereafter, the film-forming wafer is allowed to cool. During the cooling, the boat 6 continues to rotate.

Since the inside of the vacuum chamber 1 is replaced by the nitrogen gas atmosphere and the concentration of oxygen and particles in the vacuum chamber 1 is extremely low, it is convenient for maintaining the quality of the film-processed wafer 10 which is cooled. Is good. That is, in the vacuum chamber, the wafer 1
0 is spontaneously oxidized, and particularly at high temperatures, an oxide film is significantly formed on the surface of the wafer 10 so that the quality of the film-processed wafer 10 is apt to deteriorate. However, the inside of the vacuum chamber 1 is exposed to an inert nitrogen gas atmosphere. Due to the substitution, formation of a natural oxide film is prevented. In addition, the nitrogen gas atmosphere is clean, and the wafer
Pollution is also prevented.

Further, during the cooling, the boat 6 and each of the film-formed wafers 10 are rotated, so that the nitrogen gas atmosphere spreads deep into the gaps between the respective film-formed wafers 10, and Since the processed wafer 10 is uniformly cooled, good quality is maintained without spontaneous oxidation, and the cooling time is shortened, so that the cooling process time is shortened and the production efficiency of the substrate processing apparatus is improved. I do.

Further, in this embodiment, the magnetic seal unit 20 is used as a bearing of the rotation support shaft 31 of the boat 6, and the cooling fins provided on the magnetic seal unit 20 are connected to the nitrogen gas from the inert gas purge nozzle 42. Since cooling is performed by gas, piping work is easier and the material cost is lower than cooling by cooling water piping and the like, and there is no problem of water leakage, and rather, the atmosphere in the vacuum chamber 1 is improved. Useful.

Incidentally, the substrate processing apparatus of the present invention is not limited to the above-described embodiment, and not only can the boat be fixed to the rotary support shaft, but also the mounting and fixing portion of the boat can be fixed to the rotary support shaft. May be provided so that the boat can be detachably mounted so that the boat can be easily replaced. By making the boat detachable from the support shaft, the boat can be replaced, and the present invention can be applied to a two-boat type vertical diffusion semiconductor manufacturing apparatus.

[0050]

As described above, according to the present invention, the boat loaded with the substrates to be processed is rotated when the high-temperature process is performed in the reaction tube, so that each of the substrates to be processed is uniformly formed. A film-processed substrate with uniform and good quality is manufactured with high yield.

Since an inert gas such as nitrogen gas is blown from the inert gas purge nozzle to the cooling fins of the magnetic seal unit, heat transmitted from the reaction tube to the magnetic seal unit is transmitted from the cooling fins to the magnetic seal unit. Heat is removed by the active gas. The temperature rise of the magnetic seal unit is suppressed, and the sealing performance is maintained.

The structure of the inert gas purge nozzle is simple and easy to dispose, and the inert gas blown to the cooling fins replaces the inert gas in the vacuum chamber. The natural oxidation of the unprocessed substrate or the processed substrate is prevented.

Further, since the inert gas is clean, particles serving as a contaminant of the processed substrate are discharged from the vacuum chamber by the clean inert gas flow, and the inert gas flows into the cooling step after the high temperature process. Various excellent effects such as prevention of contamination of a certain processed substrate are exhibited.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the magnetic seal unit according to the embodiment.

FIG. 3 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum chamber 3 Reaction tube 4 Heater 6 Boat 10 Wafer 16 Furnace lid 20 Magnetic seal unit 23 Cooling fin 25 Large diameter rotation shaft 29 Magnetic fluid seal 31 Rotation support shaft 34 Drive unit casing 42 Inert gas purge nozzle 47 Exhaust port 49 Vacuum pump

Claims (1)

[Claims] 1. A substrate processing apparatus, wherein a boat on which a substrate is loaded is rotatably supported, a rotation support portion is hermetically sealed, and the rotation support portion is air-cooled by a cooling gas.