JP2002075888A - Method for preventing entrapment of oxygen gas in diffusion device, diffusion device and fork device suitable for use therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent entrapment of oxygen gas into a diffusion furnace (furnace tube) as much as possible, and to further prevent the entrapment of oxygen gas in a diffusion device capable of monitoring the oxygen concentration in the diffusion furnace.
Obtaining a suitable diffusion device and fork device for use in this. SOLUTION: The diffusion device 1A of the present invention includes a furnace core tube 110.
Inert gas supply pipes 115 are incorporated in the upper shutter 113a and the lower shutter 114a of the shutter, and when they are opened, the inert gas can be ejected from the ejection ports 116 formed in their inner surfaces to form the curtain C. The fork device 50A of the other invention also has a configuration in which the mounting portion 512 has a width extending in the width direction from the branch nozzles 532a, 532b, and 532c of the inert gas supply pipe 530, and the fork device 50A does not move upward. It has a structure capable of ejecting a shower of active gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing entrapment of oxygen gas in a diffusion device for diffusing impurities into a semiconductor wafer as one of the objects to be processed, a diffusion device and a fork device suitable for use in the method. It is.

[0002]

2. Description of the Related Art A conventional diffusion device will be described below with reference to the drawings. In the following description, a semiconductor wafer will be described as one of the objects to be processed.

FIG. 5 is a cross-sectional side view showing the structure and structure of a conventional diffusion device, FIG. 6 shows a semiconductor wafer loading / unloading portion of the diffusion device shown in FIG. 5, and FIG. FIG. 7 is a side view, FIG. 8B is a schematic front view thereof, and FIG. 9 shows an upper shutter of the diffusion device shown in FIGS.
FIG. A is a plan view seen from the inside, FIG. B is a side view seen from arrow B, FIG. C is a bottom view seen from arrow C, and FIG. 8 is shown in FIGS. A shows a lower shutter of the diffusion device, FIG. A is a plan view seen from the inside, FIG. B is a side view seen from an arrow B, FIG. C is a bottom view seen from an arrow C, and FIG. 9 shows a fork device used when a semiconductor wafer is put into the diffusion device shown in FIG.
FIG. A is a top view, and FIG. B is a side view.

First, the configuration and structure of a conventional diffusion device will be schematically described with reference to FIGS.

In FIG. 5, reference numeral 1 generally indicates a conventional spreader. The diffusion apparatus 1 includes a diffusion furnace section 10,
It comprises a reaction gas supply section 20, a transport section 30, and a main controller section 40.

[0006] The diffusion furnace section 10 is constituted mainly of a cylindrical furnace core tube 110 made of quartz glass placed in a horizontal state, and a heat equalizing tube 120 is provided around the outer periphery of the furnace core tube 110. The electric heater 130 is attached via the electric heater. Furnace core tube 1
A small-diameter gas supply port 111 is opened at the distal end of 10. On the other hand, at the base end of the furnace core tube 110, a large-diameter carry-in / out port 112 for carrying in / out a semiconductor wafer as an object to be processed is opened.

The loading / unloading port 112 is closed by a pair of upper shutter 113 and lower shutter 114 as shown in FIG. These upper shutter 113 and lower shutter 114
13A and 114A are supported so as to be rotatable in the vertical direction, as indicated by arrows, around respective shafts 113S and 114S disposed near the inlet / outlet 112 of the furnace core tube 110. . In the state shown by the solid line in FIG. 6, the loading / unloading port 112 is the upper shutter 113 and the lower shutter 1.
14 shows a state in which the upper and lower shutters 113 and 114 are closed by a partially overlapping structure as shown in FIG. Position.

Upper shutter 113 and lower shutter 11
Numeral 4 is a plate made of quartz glass.
13 is shown in FIG. 7, and the structure of the lower shutter 114 is shown in FIG. Free end 113B of upper shutter 113
Is formed with a semicircular notch 113C along the diameter of the furnace core tube 110 from the center edge. A substantially inverted triangular convex plate surface 114C having a uniform thickness corresponding to the plate thickness of the upper shutter 113 is formed at the center of the base end 114A of the lower shutter 114.

An electric heater 130 which surrounds the outer periphery of the furnace core tube 110 and the soaking tube 120 and is controlled by a temperature controller 131 so as to maintain the inside of the furnace core tube 110 at a desired temperature is provided. Further, an exhaust scavenger 140 is provided on an outer peripheral portion of the inlet / outlet 112 portion of the furnace core tube 110.
Are arranged.

A reaction gas supply section 20 is connected to a gas supply port 111 of the furnace core tube 110 via a joint 210. The base of the reaction gas supply unit 20 is a reaction gas source 22.
0, a reaction gas supply pipe 240 having a tip connected to the joint 210 and a mass flow controller 230 provided at an intermediate portion, and a gas controller 25.
0. The gas controller 250 controls the mass flow controller 230 and the like, and
Control the flow rate, flow rate, etc. of the reaction gas to zero.

The transport unit 30 faces the loading / unloading port 112 of the furnace core tube 110 and the fork transfer device 310
The fork device 50 described later mounted thereon is guided so that it can be carried in and out along the central axis of the furnace core tube 110. Also, the fork transfer device 31
An elevator 320 for raising and lowering the loaded boat B is provided on one side of the vicinity of the carry-in / out port 112, and a cassette station 330 is provided near this elevator 320.

The main controller 40 is a device for controlling various operations of the entire diffusion device 1 as described later.

Next, a conventional fork device 50 will be described with reference to FIG. The fork device 50 includes a fork body 510 and an inert gas supply pipe 520.

The fork main body 510 is formed of quartz glass having a predetermined length and diameter. The base 511 has a cylindrical shape, and the top has a substantially semicircular arc formed by cutting a substantially upper half tube in the length direction. It is formed and formed on the mounting portion 512 which is open.

The inert gas supply pipe 520 is provided from the base 511 of the fork main body 510 to the mounting part 512, and the base 511 or a portion provided outward from the base 511 is an inert gas supply pipe. An injection port portion 522 in which a plurality of injection ports 523 for injecting an inert gas upward are formed at a connection portion 521 connected to a supply source (not shown) and at a tip portion located at the placement portion 512 described above. Have been.

The boat B is a container that accommodates a plurality of semiconductor wafers W, is mounted on the mounting portion 512 of the fork device 50, and is carried into the furnace core tube 110. It is composed of a plurality of silicon rods that support the semicircular peripheral edge, for example, four silicon rods, two on each of the left and right sides, and a plurality of slits are formed at predetermined intervals in the longitudinal direction of these silicon rods. By inserting the lower semicircular peripheral edge of the semiconductor wafer W into the slits, a plurality of semiconductor wafers W can be supported at predetermined intervals in parallel with each other.

Next, with reference to FIGS. 5 to 9, the operation in the case where a diffusion process is performed on a semiconductor wafer as an object to be processed by using the diffusion apparatus 1 will be schematically described.

First, the upper shutters 113 and 114 of the furnace core tube 110 of the diffusion furnace unit 10 are closed, and the reaction gas source 220 of the reaction gas supply unit 20 supplies gas to the reaction gas supply tube 240, the joint 210 and the furnace core tube 110. A predetermined amount of reaction gas is injected at a predetermined speed through the port 111, and the furnace tube 11 is controlled by the electric heater 130 under the control of the temperature controller 131.
The inside of 0 is heated to a predetermined temperature.

On the other hand, the plurality of semiconductor wafers W carried into the cassette station 330 are
The boat B is transferred to an empty boat B which is placed on standby and the elevator B is raised and the boat B is transported to the height position of the fork device 50 which is waiting at a predetermined height position, The fork device 50 is mounted on the mounting portion 512. The fork device 50 on which the boat B is placed is guided by the fork transfer device 310, and the inert gas supply pipe 5
An inert gas, for example, a nitrogen gas (N 2) is ejected from the injection port portion 522 of the nozzle 20 and is conveyed to the loading / unloading port 112 of the furnace core tube 11 while leaving a shower. The upper shutter 113 and the lower shutter 11 closing the loading / unloading port 112
4 is opened and carried into a predetermined position in the furnace core tube 110 from the carry-in / out port 112. The fork device 50 leaves the boat B, retreats, returns to the original predetermined position,
Reference numerals 3 and 114 close the loading / unloading port 112.

The surfaces of the plurality of semiconductor wafers W carried in are subjected to a desired diffusion process. When the diffusion operation is completed, the upper shutter 113 and the lower shutter 114 are opened in a manner opposite to the loading operation, the fork device 50 enters the furnace core tube 110, and the predetermined boat B is placed on the mounting portion 512.
, Retreat to a predetermined position outside the furnace core tube 110, and are transferred to a cassette that is waiting at the cassette station 330.

These various operations are controlled by the main controller 40.

[0022]

As described above, the fork device 50 injects a shower of nitrogen gas as described above, but only injects it from directly below the semiconductor wafer W held therein. When the fork device 50 places the boat B and carries the boat B into the furnace core tube 110, the nitrogen gas shower causes oxygen to be entrained on the contrary, and the oxygen enters the inside through the carry-in / out port 112.

Further, there is no means for detecting the oxygen concentration in the furnace core tube 110, and the diffusion operation proceeds in a state where the oxygen concentration is high. As a result, the surface resistance σs of the layer subjected to the diffusion treatment fluctuates, Inconvenient events such as abnormalities in the film thickness have occurred.

Accordingly, the present invention is intended to solve such a problem, and it is possible to prevent entrainment of oxygen gas into a diffusion furnace (core tube) as much as possible, and furthermore, to prevent oxygen concentration in the diffusion furnace from increasing. It is an object of the present invention to obtain a method of preventing entrapment of oxygen gas in a diffusion device capable of monitoring the above, and to obtain a suitable diffusion device and fork device using the method.

[0025]

Therefore, in the invention according to the first aspect, in the diffusion device, when the semiconductor wafer held by the fork device is inserted into the furnace core tube through the opening of the furnace core tube, The above problem is solved by adopting a method of preventing entrainment of oxygen gas by forming a curtain of an inert gas in front of the opening of the furnace core tube.

According to a second aspect of the present invention, in the method for preventing entrainment of oxygen gas in the diffusion apparatus according to the first aspect of the present invention, the curtain is arranged such that the curtain moves in a direction in which the semiconductor wafer is introduced into the furnace core tube. The above problem is solved by using a curtain that extends in the vertical direction.

According to the third aspect of the present invention, a gas supply port is formed at one end, and the other end is open, and a vertically open shutter that can open and close the opening is attached. Sometimes after the semiconductor wafer held in the boat is thrown into the inside from the opening, the opening is closed by the upper and lower opening shutters, uniformly heated to a predetermined temperature, and then the reaction gas is supplied from the supply port to supply the semiconductor. In a diffusion device including a furnace core tube for performing diffusion processing on a surface of a wafer, a plurality of gas injection ports are formed on each inner surface of the vertically opened shutter, and an inert gas supply source is connected to the gas injection ports. When the vertical opening shutter is opened and the semiconductor wafer is introduced into the furnace core tube through the opening, an inert gas is supplied from the inert gas supply source to the vertical opening shutter. Supplied, by injection from the gas injection port, and employs a configuration to form an inert gas curtain in front of the opening, it has solved the above problems.

Further, in the invention according to claim 4,
In the diffusion apparatus according to the third aspect of the present invention, the problem is solved by disposing an oxygen gas detection element in the furnace core tube.

Furthermore, in the invention according to claim 5, the fork device is formed of quartz glass having a predetermined length and width, and the base has a cylindrical shape and the other end has an arc-shaped opening at the upper end. The fork body formed on the mounting portion and the fork body are disposed from the base portion to the mounting portion, and the base portion or a portion provided outward from the base portion is not provided. An inert gas supply in which a plurality of injection holes for injecting an inert gas upward are formed at a connection portion connected to the active gas supply source and at a portion located at the mounting portion; In a fork device provided with a pipe, the injection port portion is constituted by a plurality of branch nozzles extending in the width direction of the fork body, and a plurality of injection ports are formed in each of the branch nozzles to solve the problem. ing.

Therefore, according to the first aspect of the present invention,
It is possible to form a curtain of an inert gas that covers the loading / unloading port of the furnace core tube, and it is possible to prevent oxygen from getting into the furnace core tube.

According to the second aspect of the present invention,
It is possible to form a curtain of an inert gas that sufficiently covers the loading / unloading port of the furnace core tube, and it is possible to more reliably prevent oxygen from being caught in the furnace core tube.

Further, according to the third aspect of the present invention, it is possible to form a curtain of an inert gas that covers the loading / unloading port of the furnace core tube, and it is possible to prevent oxygen from entering into the furnace core tube.

According to the fourth aspect of the present invention, the concentration of oxygen gas in the furnace core tube can be determined, and defects in the diffusion layer can be prevented.

Further, according to the fifth aspect of the present invention, the inert gas curtain covering the inlet / outlet of the furnace core tube can be more effectively used by using together with the diffusion device of the third aspect of the present invention. And the entrapment of oxygen into the furnace core tube can be more reliably prevented.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, a method for preventing entrainment of oxygen gas in a diffusion device according to an embodiment of the present invention will be described.
A diffusion device and a fork device suitable for this will be described.

FIG. 1 is a schematic diagram showing a state in which a semiconductor wafer loading / unloading portion of a furnace core tube of a diffusion apparatus according to an embodiment of the present invention is open, and FIG. B
2 schematically shows the upper shutter of the diffusion device shown in FIG. 1, FIG. 2A is a plan view seen from the inside, and FIG. 2B is a side view seen from the arrow B. FIG. 4C shows the lower shutter viewed from the arrow C, FIG. 4 shows the lower shutter of the diffusion device shown in FIG. 1, FIG. 4A shows a plan view seen from the inside thereof, and FIG. FIG. 4 is a side view as viewed from an arrow B, FIG. 4C is a bottom view as viewed from an arrow C, and FIG. 4 shows a fork device used when a semiconductor wafer is taken in and out of the diffusion device shown in FIG. FIG. A is a top view, and FIG. B is a side view.

In the present invention, the same components as those of the diffusion device and the fork device of the prior art are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 1, reference numeral 1A indicates a spreading device according to an embodiment of the present invention. Also in this diffusion device 1A,
In the vicinity of the inlet / outlet 112 of the furnace core tube 110, an upper shutter 113a and a lower shutter 114a which open and close the inlet / outlet 112 are provided with respective shafts 113S, 11S.
Each of them is rotatable about the 4S in the vertical direction, and is supported so as to stay at a horizontal position.

As shown in FIG. 2, the upper shutter 113a is provided with a branch pipe 115a branched into a Y-shape from the base end 113A thereof.
Is connected to an inert gas supply pipe 115. Similarly, as shown in FIG. 4, the lower shutter 114a also has a branch pipe 1 that is substantially V-shaped branched from its base end 114A.
The branch pipe 115b is also connected to the inert gas supply pipe 115, and the other end of the inert gas supply pipe 115 is connected to an inert gas source (not shown). And, at the tip of the branch pipe 115a of the upper shutter 113a and the branch pipe 115b of the lower shutter 114a,
A plurality of gas injection ports 116 are open.

When the upper shutter 113a and the lower shutter 114a are opened horizontally, and the semiconductor wafer W is loaded into the furnace core tube 110 through the loading / unloading port 112, the inert gas is supplied from the inert gas supply source. An inert gas (for example, nitrogen gas) is supplied to the upper shutter 113a and the lower shutter 114a through the gas supply pipe 115, and the inert gas is ejected from the gas ejection port 116 in the vertical direction facing each other. It is configured so that a gas curtain C can be formed.

An oxygen gas detecting element 60 is provided inside the furnace core tube 110, and the output of the oxygen gas detecting element 60 is provided to the gas controller 250 or the main controller unit 40 provided outside the furnace core tube 110. Oxygen concentration detector 6
The diffusion operation is interrupted when the oxygen concentration measured by the oxygen concentration detector 61 exceeds a predetermined value.

On the other hand, the fork device 5 as one of the present inventions
As shown in FIG. 4, OA includes a fork main body 510 and an inert gas supply pipe 530.

The fork main body 510 is formed of quartz glass having a predetermined length and diameter. The base 511 has a cylindrical shape, and the top end has a substantially semi-circular shape with a substantially upper half tube cut in the length direction. It is formed and formed on the mounting portion 512 which is open.

The inert gas supply pipe 530 in the fork device 50A is connected to the base 5 of the fork main body 510.
It is arranged from 11 to the mounting portion 512. The base protrudes outward from the base 511 of the fork main body 510 and is formed as a connecting portion 531 connected to an inert gas supply source (not shown). A plurality of, in the example shown, a trifurcated trifurcated branch nozzle 532
a, 532b and 532c. These branch nozzles 532a, 532b, 532c
Are arranged along the circular arc surface of the bottom surface of. A plurality of injection ports 53 are provided at predetermined intervals on the upper surface of each branch nozzle 532a, 532b, 532c so that an inert gas (for example, nitrogen gas) can be injected upward.
3 is open.

Next, the operation when the diffusion process is performed on the semiconductor wafer W by using the above-described diffusion device 1A and fork device 50A will be described.

First, the upper shutter 113a and the lower shutter 114a of the furnace core tube 110 of the diffusion furnace unit 10 are closed, and the reaction gas source 220 of the reaction gas supply unit 20 receives the reaction gas supply tube 240, the joint 210 and the furnace core tube 110. A predetermined amount of reaction gas is injected at a predetermined speed through the gas supply port 111 of the furnace, and the furnace core 110 is heated to a predetermined temperature by the electric heater 130 under the control of the temperature controller 131.

On the other hand, the plurality of semiconductor wafers W carried into the cassette station 330 are
Is transferred to an empty boat B which is placed on standby and the boat B is transported to the height position of the fork device 50A which is waiting at a predetermined height position by raising the elevator 320, It is mounted on the mounting portion 512 of the fork device 50A. Fork device 50 on which the boat B is mounted
A is guided to the fork conveying device 310, and the branch nozzles 532a, 532b, 532c of the inert gas supply pipe 530 are provided.
, An inert gas, for example, a nitrogen gas (N 2) is jetted out of the boat B, and is conveyed to the front of the furnace core tube 110 while emitting a shower that spreads in the width direction of the boat B. Therefore, upper shutter 1
13a and the lower shutter 114a are opened, and inert gas is ejected from both gas ejection ports 116 in the vertical direction facing each other to form an inert gas curtain C in front of the loading / unloading port 112. The boat B is carried into a predetermined position in the furnace core tube 110 from the opened carry-in / out port 112 of the furnace core tube 110 in such a state. Fork device 50A
Leaves the boat B in the furnace core tube 110 and retreats and is taken out of the loading / unloading port 112, so that the upper shutter 113
First, a rotates downward and closes the loading / unloading port 112. During this time, in order to prevent any entrainment of oxygen gas, nitrogen gas is blown out from the gas injection port 116 of the lower shutter 114a that is still open. . When the upper shutter 113a closes the loading / unloading port 112, the lower shutter 114a
Is rotated upward so that its free end 114B overlaps a part of the free end 113B of the upper shutter 113a, and the upper shutter 113a and the lower shutter 114a carry the loading / unloading port 112.
Completely closed. During this time, the fork device 50A returns to the original predetermined position. Immediately before closing the loading / unloading port 112, the injection of nitrogen gas from the upper shutter 113a and the lower shutter 114a is stopped.

The plurality of semiconductor wafers W loaded are subjected to a desired diffusion process. When the diffusion operation is completed, first, the lower shutter 114a is opened, and nitrogen gas is injected. Then, the lower shutter 114a is opened, and nitrogen gas is injected. A vertical inert gas curtain C as described above is formed in front of 112. The upper shutter 113a and the lower shutter 114a are opened, the fork device 50A enters the furnace core tube 110, and the predetermined boat B is placed on the mounting portion 51.
2 and retreat while injecting inert gas,
10 and return to the predetermined position outside
It is transferred to the Casset waiting at 0.

As described above, when the fork device 50A enters and exits the furnace core tube 110, as shown in FIG. 1, the inert gas flows from the upper shutter 113a and the lower shutter 114a which are opened in the vertical direction in parallel with each other. (Nitrogen gas N2
) Are ejected in the vertical direction facing each other to form a curtain C of inert gas,
3A and fork device 50A between lower shutter 114a.
When the mounting portion 512 is located, the inert gas is sprayed upward from the branch nozzles 532a, 532b, and 532c of the mounting portion 512 in a spread manner, and an upward curtain is formed as a whole. With these curtains, entrainment of oxygen gas O2 into the entrance 112 of the furnace core tube 110 can be significantly reduced.

In this manner, the oxygen concentration in the furnace core tube 110 can be kept within a predetermined allowable range. The control of the oxygen concentration in the furnace core tube 110 is detected by the oxygen gas detection element 60 and monitored by the oxygen concentration detector 61. If the oxygen concentration in the furnace core tube 110 exceeds a specified value, the oxygen concentration detector 61 detects this, and under the control of the main controller 40, after the current diffusion process is completed. Then, the operation of the diffusion furnace section 10 is stopped.

[0051]

As described above, according to the method for preventing entrainment of oxygen gas in the diffusion apparatus of the present invention, the diffusion apparatus and the fork apparatus suitable for use in the method, The shutter of the furnace core tube has a function of forming a curtain of inert gas, so that when the loading / unloading port of the furnace core tube is opened, the curtain reduces the entrainment of oxygen gas into the furnace core tube. Can be done 2. The fork device is provided with a plurality of branch nozzles extending in the width direction, so that a plurality of semiconductor wafers mounted on the mounting portion are covered with an inert gas shower that is directed upward from directly below. 2. It can be put in and out of the furnace core tube, and the chance of oxidation by contact with oxygen gas can be greatly reduced. 3. The effects of the above items 1 and 2 can be combined to further reduce the entrapment of oxygen gas into the furnace core tube. When the oxygen concentration in the furnace core tube exceeds the specified value, the diffusion device stops operating, and a number of excellent effects can be obtained, such as minimizing the generation of defective products.

[Brief description of the drawings]

1 schematically shows a state in which a semiconductor wafer loading / unloading portion of a furnace core tube of a diffusion apparatus according to an embodiment of the present invention is open, FIG. 1A is a side view thereof, and FIG. It is the front view.

2 schematically shows an upper shutter of the diffusion device shown in FIG. 1; FIG. 2A is a plan view viewed from the inside; FIG. 2B is a side view viewed from an arrow B; C is a bottom view seen from arrow C.

3A and 3B show a lower shutter of the diffusion device shown in FIG. 1, wherein FIG. 3A is a plan view seen from the inside, FIG. 3B is a side view seen from an arrow B, and FIG. FIG. 4 is a bottom view as viewed from a view C;

FIGS. 4A and 4B show a fork device used when a semiconductor wafer is taken in and out of the diffusion device shown in FIG. 1, FIG. A is a top view thereof, and FIG. B is a side view thereof.

FIG. 5 is a cross-sectional side view showing the configuration and structure of a conventional diffusion device.

6 shows a semiconductor wafer loading / unloading portion of the diffusion device shown in FIG. 5, wherein FIG. A is a schematic side view thereof, and FIG. B is a schematic front view thereof.

7A and 7B show an upper shutter of the diffusion device shown in FIGS. 5 and 6, wherein FIG. 7A is a plan view seen from the inside, FIG. 7B is a side view seen from an arrow B, and FIG. Is a bottom view seen from arrow C. FIG.

8 shows the lower shutter of the diffusion device shown in FIGS. 5 and 6, wherein FIG. 8A is a plan view seen from the inside, FIG. 8B is a side view seen from arrow B, and FIG. C is a bottom view seen from arrow C.

9 shows a fork device used when a semiconductor wafer is loaded into the diffusion device shown in FIG. 5, and FIG.
Is a top view thereof, and FIG. B is a side view thereof.

[Explanation of symbols]

1A: diffusion apparatus according to an embodiment of the present invention, 10: diffusion furnace section, 120: heat equalizing tube, 130: electric heater, 110: furnace core tube, 113a: upper shutter, 114a: lower shutter, 115: inert gas Supply pipe, 115a: branch pipe of the inert gas supply pipe 115, 116: injection port, 140: exhaust scavenger, 20: reactive gas supply section, 30: transport section, 310: fork transport apparatus, 320: elevator,
330: Casset station, 40: Main controller, 50A: Fork device of one embodiment of the present invention, 510: Fork body, 511: Fork body 51
0, 512 ... Placement of fork body 510, 53
0: inert gas supply pipe, 531: inert gas supply pipe 53
0, 532a, 532b, 532c: branch nozzle of the inert gas supply pipe 530; 160: oxygen gas detecting element; 61: oxygen concentration detector

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/205 H01L 21/205

Claims (5)

[Claims] 1. A curtain made of an inert gas is formed in front of an opening of a furnace core tube when an object to be processed held by a fork device is introduced into the furnace core tube opening of the diffusion device through the opening. A method for preventing entrainment of oxygen gas in a diffusion device. 2. The oxygen gas in the diffusion apparatus according to claim 1, wherein the curtain comprises a curtain that is directed vertically with respect to a direction in which the object to be processed is charged into the furnace core tube. Entrapment prevention method. 3. A gas supply port is formed at one end, and an open / close shutter which is open at the other end and is capable of opening and closing the opening is mounted, and when the up / down open shutter is opened, the boat is held inside the boat from the opening. After charging the processed object, the opening is closed by the upper and lower opening shutters, uniformly heated to a predetermined temperature, and then a reaction gas is supplied from the supply port to diffuse the surface of the processed object. In a diffusion device having a furnace core tube to be applied, a plurality of gas injection ports are formed on each inner surface of the vertically opened shutter, and an inert gas supply source is connected to the gas injection ports, and the vertically opened shutter is opened. When the object to be processed is introduced into the furnace core tube through the opening, an inert gas is supplied from the inert gas supply source to the vertically open shutter, and the inert gas is injected from the gas injection port. Opening Diffuser apparatus characterized by forming an inert gas curtain in front. 4. The diffusion apparatus according to claim 3, wherein an oxygen gas detection element is provided in the furnace core tube. 5. A fork main body formed of quartz glass having a predetermined length and width, a base portion formed in a cylindrical shape, and the other end formed on a mounting portion having an arc-shaped opening at an upper end. The fork main body is provided from the base to the mounting portion, and the base or a portion provided outward from the base is connected to a connection portion connected to an inert gas supply source; and An inert gas supply pipe in which a plurality of injection ports for injecting an inert gas upward into a portion located in the description mounting portion are formed, and the injection port portion is formed. A fork device comprising a plurality of branch nozzles extending in a width direction of a fork main body, and a plurality of injection ports formed in each of the branch nozzles.