JPH0897165A - Surface treatment method for surface-treated workpiece and air entrapment prevention jig used in the method - Google Patents

Abstract

(57) [Summary] [Objective] The object is to make the reaction gas uniform in the core tube of the horizontal heat treatment furnace so that each semiconductor wafer can be uniformly surface-treated. According to the present invention, when a plurality of semiconductor wafers S mounted on the boat 160 are housed in the core tube 100 for surface treatment, the boat 160 held by the forks 170 on the loading / unloading port 120 side. A predetermined reaction gas supplied from the gas supply port 110 is mounted on the boat by mounting a cylindrical or cylindrical air entrapment prevention jig of a predetermined length that prevents the entry of air entering from the inlet / outlet port 120. The surface treatment is performed on the plurality of semiconductor wafers S so as to prevent the air from entering through the gap of the shutter 130 portion to be non-uniform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a horizontal heat treatment furnace suitable for forming a thin film such as an oxide film on the surface of a surface-treated workpiece such as a semiconductor wafer or diffusing impurities. The present invention relates to a surface treatment method for a surface-treated workpiece that performs surface treatment by means of a surface treatment, and an air entrainment prevention jig used in the method.

[0002]

2. Description of the Related Art First, a conventional horizontal heat treatment furnace and a semiconductor wafer which is a surface-treated workpiece using the same are picked up to form an oxide film on the surface of the semiconductor wafer.
Alternatively, a case of diffusing impurities will be described with reference to the drawings.
FIG. 5 is a top view showing the configuration of a horizontal heat treatment furnace currently in use.
FIG. 6 is a partial side view of the horizontal heat treatment furnace shown in FIG.
FIG. 7 shows only the core tube of the horizontal heat treatment furnace of FIG. 6, FIG. 7A is a sectional side view thereof, and FIG.
8 is a cross-sectional view taken along line A, FIG. 8 is a distribution diagram showing distribution of various gases in the core tube in the cross-sectional view taken along line BB of FIG. 7A, and FIG. 9 is gas distribution shown in FIG. FIG. 7 is a partial cross-sectional view of the tube body for explaining how a plurality of semiconductor wafers in the reaction chamber of the tube body are adversely affected by.

First, a horizontal heat treatment furnace currently in use will be described with reference to FIGS. Reference numeral 200 generally indicates an existing horizontal heat treatment furnace. This horizontal heat treatment furnace 200 includes a quartz core tube 100, a core body 210 including a heater (not shown) for heating the quartz, and pressures and flow rates of various reaction gases from various reaction gas sources (not shown). And a mass flow controller 220 that controls the core tube 100 to supply the various reaction gases to the core tube 100, and a plurality of semiconductor wafers S housed in a carrier (not shown) are transferred to the quartz boat 160, or On the contrary, in order to insert or take out the clean bench 230, which is a place for transferring, and the quartz boat 160, on which a plurality of semiconductor wafers S are mounted at a predetermined interval, into or from the core tube 100. From a support guide device 240 including a support member 241 for supporting the quartz fork 170 and a guide rail 242 for guiding the same. It has been made.

Further, the fork 170 is formed in a flat shape with its tip having a certain width, and the tip of that shape is inserted into the bottom surface of the boat 160, that is, the boat 160 has its flat tip. The support member 241 supported on the base of the fork 170 is supported by the guide rail 242 so that the support member 241 can move in the horizontal direction indicated by the arrow X and in the vertical direction indicated by the arrow Y. The structure is such that the boat 160 can be placed in the central portion so as not to contact the inner wall of the core tube 100.

As shown in FIG. 7, the core tube 100 has a gas supply port 110 formed at one end of a dome shape of a tube body 101, and an inlet / outlet port 120 having an entire surface opened at the other end. A shutter 130 that opens and closes the inlet / outlet 120 is attached to the inlet / outlet 120. The gas supply port 1
From 10 to the middle of the tube body 101, the reaction chamber 140
A gas exhaust unit 150 is formed between the reaction chamber 140 and the inlet / outlet port 120, and the gas exhaust unit 150, as shown in FIG.
A small opening 151 formed on the side wall of 01 and this opening 1
51 and an exhaust pipe 152 leading to 51.

By using the horizontal heat treatment furnace 200 having such a configuration, impurities can be diffused on the surface of the semiconductor wafer S, and the surface can be oxidized or annealed. For example, when diffusing impurities on the surface of the semiconductor wafer S, the boat 160 holding a plurality of semiconductor wafers S at predetermined intervals is placed on the tip of the fork 170, the support guide device 240 is operated, and Core tube 100
Of the core body 210 after opening the shutter 130 of the above, storing it in the reaction chamber 140 of the tube body 101 through the inlet / outlet port 120, and closing the shutter 130.
While heating with a heater (not shown), the reaction gas is supplied from the mass flow controller 220 through the gas supply port 110, and the exhaust gas is exhausted through the opening 151 and the exhaust pipe 152.

When phosphorus is diffused as an impurity on the surface of the semiconductor wafer S, the inside of the tube body 101 is 700-1.
After heating to 000 ° C., N ₂ 19.5 liter POCl ₃ 73 mg O ₃ 320 cc is used as a reaction gas per minute. Thus, phosphorus diffuses on the surface of the semiconductor wafer S, and Cl ₂ or the like is exhausted from the exhaust pipe 152.

When oxidizing the surface of the semiconductor wafer S, oxygen gas O ₂ and hydrogen gas H ₂ are supplied through the gas supply port 110, and when annealing is performed, nitrogen gas N ₂ is supplied through the gas supply port 110. Supply ₂ .

[0009]

However, at the time of performing the heat treatment as described above, air enters at the same time as the semiconductor wafer S is taken in and out of the core tube 100, and
Even during the heat treatment with the shutter 130 closed, air enters through the gap between the shutter 130 and the inlet / outlet port 120, and the opening 151 and the exhaust pipe 152 are formed only at one place on the side wall of the tube body 101. As shown in FIG. 8, the distribution of various gases in the reaction chamber 140 near the opening 151 of the tube body 101 is such that the reaction gas is biased toward the exhaust pipe 152 side and the reaction gas concentration in the exhaust pipe 152 is Is low, and the bottom is mostly air. That is, the reaction gas concentration in the tube body 101 becomes non-uniform, and as shown in FIG. 9, among the plurality of semiconductor wafers S standing on the boat 160, the loading / unloading port 1
The semiconductor wafer S within the range of the distance L on the 20 side (hereinafter referred to as “front side”) is the oxygen gas O ₂ in the air.
Under the influence of the above, when the impurities are diffused, phosphorus cannot be uniformly diffused on the surface of the semiconductor wafer S, the sheet resistance becomes high, and when the heat treatment is oxidation, the oxide film thickness becomes thick. There was a shortcoming.

Therefore, up to now, a large number of dummy wafers M, for example, 75 dummy wafers M are erected on the boat 160 within the range of the distance L on the front side so that the true semiconductor wafer S is not adversely affected. Was taken. But,
In such measures, as many as 75 dummy wafers M have to be transferred to the boat 160, which reduces work efficiency.

Therefore, according to the present invention, the reaction chamber 140 is
It is an object of the present invention to provide a surface treatment method for a surface-treated workpiece capable of efficiently preventing unevenness of heat treatment on the surface of a semiconductor wafer S due to non-uniformity of reaction gas concentration in the inside, and an air entrapment prevention jig used in the method. To do.

[0012]

SUMMARY OF THE INVENTION Therefore, the surface treatment method for a surface-treated workpiece according to the present invention includes a reaction gas supply port, a reaction chamber, an inlet / outlet port for a semiconductor wafer which is the surface-treated workpiece, and a gas exhaust section. A plurality of semiconductor wafers mounted on a boat using a horizontal heat treatment furnace composed of a core tube in which are formed are housed in the reaction chamber by the forks through the loading / unloading port, and the semiconductor wafers subjected to surface treatment are subjected to surface treatment. In the surface treatment method, when a plurality of semiconductor wafers mounted on the boat are housed in the reaction chamber to perform surface treatment, a predetermined length is provided on the loading / unloading port side of the boat mounted on the reaction chamber. A cylindrical or cylindrical air entrainment prevention jig is placed, a predetermined reaction gas is supplied from the reaction gas supply port, and the air entrainment prevention jig is used to discharge the air. Re so as to prevent air entering from the mouth, it has solved the above problems.

The air entrainment prevention jig has a predetermined length and a diameter smaller than the inner diameter of the core tube.
The outer peripheral surface is along the inner peripheral surface of the core tube, and on a part of the outer peripheral surface thereof, over the entire length thereof, of a width slightly wider than the width of the fork for mounting or demounting the boat on which the semiconductor wafer is mounted on the core tube. It has a structure in which a groove is formed.

[0014]

Therefore, since only the air entrainment preventing jig exists in the non-uniform reaction gas atmosphere in the reaction chamber, the surface-treated workpiece such as a semiconductor wafer is not adversely affected. The surface of the can be subjected to a uniform surface treatment.

[0015]

EXAMPLES Next, with reference to FIG. 1 to FIG. 4, examples of the surface treatment method of the surface treated workpiece of the present invention and the air entrainment prevention jig used in this method will be explained. 1 is a perspective view showing an embodiment of an air entrainment prevention jig of the present invention, and FIG. 2 is a side view of a core tube or the like showing a state in which the air entrainment prevention jig shown in FIG. 1 is inserted into the core tube. 3 is a side view of the core tube showing a state in which an air entrainment prevention jig and a boat on which a semiconductor wafer is mounted are accommodated in the core tube, and FIG. FIG. 3 is a partial cross-sectional view of the tube body for explaining how a plurality of semiconductor wafers in the tube body reaction chamber of FIG. The same components as those of the conventional horizontal heat treatment furnace will be described with the same reference numerals.

First, referring to FIG. 1, an air entrainment prevention jig of the present invention (hereinafter simply referred to as "prevention jig").
An example will be described. This prevention jig 1 has a predetermined length,
That is, it has a length (see FIG. 4) corresponding to the distance L from the gas exhaust part 150 of the tube body 101 to the area where a good and uniform reaction gas exists from the gas exhaust part 150 to the inside of the reaction chamber 140, and both ends thereof are provided. The diameter D of the surfaces 2A and 2B is the tube body 10
1 is smaller than the inner diameter, and the outer peripheral surface 3 is the tube body 101.
Along the inner peripheral surface of the fork 170, and along a part of the outer peripheral surface 3 over the entire length thereof, a groove having a width W slightly wider than the width of the tip 171 of the fork 170 and a depth H deeper than the thickness of the tip 171. 4 is formed of a cylinder or a cylinder having a structure. When the end surface 2B is formed in a streamlined shape such as a dome shape or a conical shape, the reaction gas from the gas supply port 110 can smoothly flow through the reaction chamber 140 rather than a flat surface.

Next, a method of treating the surface of a semiconductor wafer with the tube body 101 using the prevention jig 1 will be described with reference to FIGS. 5, 6 and 2. First, FIG.
The boat 160 in which a plurality of semiconductor wafers S are stood at a predetermined interval is placed on the most distal portion 171 of the fork 170 by the clean bench 230 shown in FIG.
0 and the base end 172 of the fork 170.
1, the prevention jig 1 is placed with the concave groove 4 facing downward so as to be fitted into the tip portion 171 of the fork 170, and the fork 170 in that state is placed on the support guide device 24.
0 to activate and deactivate the tube body 101 inlet / outlet port 120
The boat 160 and the prevention jig 1 are loaded into the reaction chamber 140 (FIG. 2), the fork 170 is then lowered, and the boat 160 and the prevention jig 1 are placed in the reaction chamber 140.
The supporting and guiding device 240 is operated in the opposite manner to remove it from these. Then, as shown in FIG. 3, the prevention jig 1 is provided on the front side of the tube body 101, and the semiconductor wafer S loaded on the boat 160 is provided on the gas supply port 110 side (hereinafter, referred to as “rear side”). In an arrayed state, they are placed on the bottom of the tube body 101. Then, the opening / closing port 120 is closed by the shutter 130, the reaction gas is introduced into the reaction chamber 140 from the gas supply port 110, and the heat treatment work is started.

In the state shown in FIG. 3, as shown in FIG. 4, the prevention jig 1 exists in the reaction gas in the non-uniform state, and a plurality of semiconductor wafers loaded on the boat 160 are loaded. All S can be present in the good homogeneous reaction gas. The method of performing heat treatment in such a state is the surface treatment method of the surface-treated workpiece of the present invention and the method thereof.

Therefore, during the heat treatment, even if the shutter 1
Even if air enters from 30, the air will be prevented by the jig 1.
Acts as a cap, and is blocked by the cap so as not to go around to the semiconductor wafer S existing on the rear side. On the other hand, the reaction gas from the gas supply port 110 fills the reaction chamber 140, and after the surface treatment of each semiconductor wafer S, the prevention jig 1
Is guided to the outer peripheral surface 3 of the outer peripheral surface 3 and the tube body 1.
The gas is exhausted from the gas exhaust unit 150 through a gap between the inner peripheral surface of the gas generator 01.

[0020]

As described above, according to the surface treatment method of the surface treated workpiece of the present invention, the prevention jig is mounted on the fork in front of the boat without using a large number of dummy wafers M. With a simple operation, the fork can store the semiconductor wafer in the reaction chamber, and at the same time, the prevention jig can be stored, and the adverse effect of air entrapment can be prevented without affecting the semiconductor wafer. Can be filled with a uniform reaction gas. Therefore, all the semiconductor wafers on the front side can be uniformly surface-treated. Furthermore, the air entrainment prevention jig of the present invention has a simple structure and can be manufactured extremely easily.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an air entrainment prevention jig of the present invention.

FIG. 2 is a side view of the core tube and the like showing a state in which the air entrainment prevention jig shown in FIG. 1 is inserted into the core tube.

FIG. 3 is a side view of the core tube showing a state in which an air entrainment prevention jig and a boat on which a semiconductor wafer is mounted are housed in the core tube.

FIG. 4 is a partial cross-sectional view of the tube body for explaining how the plurality of semiconductor wafers in the tube body reaction chamber of the core tube are favorably heat-treated by the air entrainment prevention jig shown in FIG.

FIG. 5 is a top view showing a configuration of a currently used horizontal heat treatment furnace.

6 is a partial side view of the horizontal heat treatment furnace shown in FIG.

7 shows only the core tube of the horizontal heat treatment furnace of FIG. 6, FIG. 7A is a sectional side view thereof, and FIG. 7B is a sectional view taken along the line AA of FIG.

FIG. 8 is a distribution diagram showing distributions of various gases in a core tube in a cross-sectional view taken along the line BB of FIG. 7A.

FIG. 9 is a partial cross-sectional view of the tube body for explaining how a plurality of semiconductor wafers in the reaction chamber of the tube body are adversely affected by the gas distribution shown in FIG.

[Explanation of symbols]

 S Semiconductor wafer 1 Air entrapment prevention jig 2A End surface 2B End surface 3 Outer peripheral surface 4 Recessed groove 100 Core tube 101 Tube body 110 Gas supply port 120 Inlet / outlet port 130 Shutter 140 Reaction chamber 150 Gas exhaust part 160 Boat 170 Fork 171 Tip of fork 170 172 Base end of fork 170 200 Horizontal heat treatment furnace 210 Core body 220 Mass flow controller 230 Clean bench 240 Support guide device 241 Support member 242 Guide rail

Claims (2)

[Claims] 1. A plurality of objects to be placed on a boat using a horizontal heat treatment furnace comprising a core tube including a reaction gas supply port, a reaction chamber, an inlet / outlet port for a surface-treated workpiece, and a gas exhaust part. In the method of surface-treating a surface-treated workpiece in which the surface-treated workpiece is housed in the reaction chamber by a fork through the inlet / outlet, and the surface-treated workpiece is subjected to surface treatment, a plurality of workpieces placed on the boat are placed. When a surface-treated product is housed in the reaction chamber for surface treatment, a columnar or cylindrical air entrapment preventive treatment having a predetermined length on the side of the loading / unloading port of the boat placed in the reaction chamber. A predetermined reaction gas is supplied from the reaction gas supply port by mounting a tool, and while the air entrainment prevention jig prevents air from entering through the inlet / outlet port, the reaction gas causes the plurality of surfaces to be exposed. A surface treatment method for a surface-treated workpiece, which comprises subjecting a surface-treated workpiece to a surface treatment. 2. A semiconductor having a predetermined length, a diameter smaller than the inner diameter of the core tube, an outer peripheral surface along the inner peripheral surface of the core tube, and a part of the outer peripheral surface over the entire length thereof. A cylindrical or cylindrical air entrainment prevention jig in which a groove having a width slightly wider than the width of a fork for attaching or detaching a boat on which a wafer is mounted to or detached from the core tube is formed.