JPH0653154A - Impurity diffusion furnace in semiconductor manufacturing device - Google Patents

Abstract

PURPOSE:To form diffusion layers of uniform impurity concentration in a plurality of silicon wafers by enlarging a hole diameter of each gas blow-off port of an injector gradually as a distance from a gas in-flow port to an injector increases and by making an amount of gas blown out of each gas blow-off port equal. CONSTITUTION:A gas in-flow port 12 at one end of an injector is for introducing carrier nitrogen gas 8, O2 gas 9 and PH3 gas 10 into the injector. A plurality of gas blow-off ports 13 are arranged all over the injector, and the hole diameter is formed to enlarge gradually as a distance from the gas in-flow port 12 increases. Thereby, gas of approximately the same amount is blown off from each gas blow-off port 13 regardless of a distance from the gas in-flow port 12. According to this constitution, a diffusion layers of uniform impurity can be formed in a plurality of silicon wafers which are arranged along a longitudinal direction of the injector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impurity diffusion furnace in semiconductor manufacturing equipment.

[0002]

2. Description of the Related Art Conventionally, in the impurity diffusion technique at the time of manufacturing a semiconductor, atoms of another kind are thermally infiltrated into a substrate crystal to change the bulk property. The most commonly used method in the past is to form a glass layer containing impurity atoms on the surface of the substrate, perform an oxidation-reduction reaction between the glass layer and the substrate atoms, and substitute the impurity atoms into the substrate. It is to diffuse.

As an impurity diffusion furnace used for such impurity diffusion, a vertical impurity diffusion furnace for diffusing phosphorus as an impurity in a silicon wafer will be described. FIG. 2 is a diagram showing a configuration of a conventional vertical impurity diffusion furnace. In FIG. 2, a quartz board 3 is installed in the quartz tube 2,
A plurality of silicon wafers 4 are mounted on the quartz board 3. An injector 5 that is long in the vertical direction is installed facing the opening side of the quartz board 3. Injector 5
Has a gas outlet 13 over its entire length, one end of which is connected to the gas inlet 12. Further, the injector 5 is connected to the outside of the quartz tube 2 through an inflow port 12, and inflow ports for carrier nitrogen gas 8, O ₂ gas 10 and PH ₃ gas 9 are provided outside the injector 5, respectively. A nitrogen gas nozzle 7 for introducing an atmospheric nitrogen gas 11 is provided above the quartz tube 2, and an exhaust port 6 is provided below. A heater 1 is installed outside the quartz tube 2.

FIG. 3 is a schematic view of a conventional injector-5. In FIG. 3, 12 at one end of the injector 5 is a gas inlet port, and carrier nitrogen gas 8 and
This is for introducing O ₂ gas 10 and PH ₃ gas 9 gas into the injector 5. Reference numeral 13 denotes a gas ejection port, which is arranged in plural numbers in the length direction of the injector 5 and has the same hole diameter.

The operation of the conventional vertical impurity diffusion furnace configured as described above will be described. The silicon wafer 4 mounted on the quartz board 3 in the quartz tube 2 is heated to 800 to 1000 ° C. by the heater-1. The PH ₃ gas 9 flows in together with the O ₂ gas 10 and the nitrogen gas 8 from the gas inflow port 12 of the injector 5, and is ejected from the gas ejection port 13 toward the silicon wafer 4. The PH ₃ gas 9 and the O ₂ gas 10 react on the surface of the silicon wafer 4 to form phosphorus glass. Phosphorus in the phosphorus glass is diffused into the bulk of the silicon wafer 4 by thermal diffusion to form a diffusion layer. During the reaction,
Atmospheric nitrogen gas 11 is introduced from the nitrogen gas nozzle 7, and this gas 11, excess nitrogen gas 8 and PH ₃ gas 9 are introduced.
And O ₂ gas 10 are discharged from the exhaust port 6.

[0006]

However, in the above-mentioned conventional injector, since the hole diameters of all the gas ejection ports 13 are equal, the PH ₃ gas 9, the O ₂ gas 10 and the nitrogen gas 8 flow in the gas flow. There is a tendency that the closer to the inlet 12, the larger the ejection amount from the gas ejection port 13, and the farther from the gas inlet 12 the smaller the ejection amount from the gas ejection port 13. Therefore, the wafer 4 above the quartz board 3 has a drawback that the impurity concentration of the diffusion layer is lower than that of the wafer 4 below.

The present invention solves the above problems, and an object thereof is to form an impurity diffusion layer having a uniform concentration on a plurality of silicon wafers.

[0008]

In order to solve the above problems, an impurity diffusion furnace in a semiconductor manufacturing apparatus of the present invention comprises an injector having a plurality of gas ejection ports, and the hole diameter of the gas ejection port of the injector is The injector was formed to be gradually larger as the distance from the gas inlet to the injector was increased.

[0009]

With the above structure, since the hole diameter is small at the gas ejection port near the gas inlet port, the gas ejection amount is small, and the gas supply amount to the location distant from the gas inlet port is large. Therefore, it is possible to equalize the gas ejection amount from the gas ejection port far from the gas ejection port and the gas ejection amount from the gas ejection port near the gas inflow port. By thus equalizing the amount of gas ejected from each gas ejection port, it is possible to form an impurity diffusion layer having a uniform concentration on a plurality of silicon wafers.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of an injector-5 of an impurity diffusion furnace according to the present invention. In FIG. 1, 12 at one end of the injector 5 is a gas inlet, which is a carrier nitrogen gas 8, O ₂ gas 10, and PH ₃
It is for introducing the gas 9 and the gas into the injector 5. Reference numeral 13 is a gas ejection port, which is an injector 5
Are arranged over the entire length of. Gas spout 1
No. 3 is configured such that its hole diameter gradually increases as the distance from the gas inlet 12 increases. That is, the injector 5 is divided into three parts, that is, an A part, a B part, and a C part in order from the side closer to the gas inlet 12. The hole diameter of the gas ejection port 13 in the A portion is 2 mmφ and the pitch is 6 mm. The diameter of the gas outlet 13 in the B section is 3
mmφ and the pitch is 6 mm. The hole diameter of the gas ejection port 13 in the C portion is 4 mmφ and the pitch is 6 mm.

The operation of the above configuration will be described below.
The PH ₃ gas 9 flows in together with the O ₂ gas 10 and the nitrogen gas 8 from the gas inlet 12 of the injector. Since the hole diameter is small at the gas ejection port 13 close to the gas inflow port 12, the gas ejection amount is small, and the gas supply amount to a portion far from the gas inflow port 12 is large. This makes it possible to make the gas ejection amount from the gas ejection port 13 far from the gas inflow port 12 equal to the gas ejection amount from the gas ejection port 13 near the gas inflow port 12.

[0012]

As described above, according to the present invention, in the injector of the impurity diffusion furnace in the semiconductor manufacturing apparatus, the plurality of gas ejection holes having the hole diameter gradually increased as the distance from the gas inlet increases. By providing
It is possible to eject almost the same amount of gas regardless of the distance from the gas ejection port. As a result, it becomes possible to form an impurity diffusion layer having a uniform concentration on a plurality of silicon wafers arranged along the length direction of the injector.

[Brief description of drawings]

FIG. 1 is a schematic view of an injector for a vertical impurity diffusion furnace according to the present invention.

FIG. 2 is a cross-sectional view showing the structure of a conventional vertical impurity diffusion furnace.

FIG. 3 is a schematic view of a conventional injector for a vertical impurity diffusion furnace.

[Explanation of symbols]

 5 Injector 12 Gas inlet 13 Gas jet

Claims (1)

[Claims] 1. An injector having a plurality of gas ejection ports, wherein the hole diameter of the gas ejection port of the injector is
An impurity diffusion furnace in a semiconductor manufacturing apparatus, characterized in that the injector is formed so that it gradually becomes larger as the distance from the gas inlet to the injector becomes larger.