JPH0714782A - Semiconductor production equipment - Google Patents

Abstract

PURPOSE:To enhance the in-plane uniformity of thin film by straightening the flow of reaction gas in the vertical furnace tube of a thin film forming system between the reaction gas introduction port and the exhaust pipe thereby striking the gas uniformly against the wafer surface. CONSTITUTION:A plurality of exhaust holes 8 are arranged uniformly around a thermal insulation tube 5 mounted on a thermal insulation base 7 supporting a core tube 2. Consequently, the reaction gas 1 introduced into the furnace tube 2 through a gas introduction port 2a flows symmetrically to the axis of the furnace tube. The plurality of exhaust holes 8 are collected in the center on the circular bottom face of an arm 9 and coupled with one exhaust pipe 10. Consequently, the straightened reaction gas 1 is fed uniformly to the surface of a wafer 4 thus enhancing the uniformity of the thickness of film, the resistance of diffusion layer, etc., formed on the wafer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus,
In particular, it relates to a semiconductor manufacturing apparatus having a vertical furnace core tube for forming a thin film on a semiconductor wafer.

[0002]

2. Description of the Related Art In a conventional semiconductor manufacturing apparatus, particularly in a vapor phase growth apparatus or a diffusion furnace, it is required that the film thickness and the diffusion layer resistance be uniform in the wafer surface. The structure of the main part of a conventional vertical diffusion furnace will be described with reference to FIG. The figure (a) is a longitudinal cross-sectional view, and the figure (b) is the BB arrow view.

A boat 3 on which a wafer 4 is mounted is placed on a heat retaining cylinder 5, and the boat 3 is loaded from the lower opening of the furnace core tube 2 by a vertically moving mechanism (not shown) of an arm 9. Insulation cylinder 5
Is fixed on the arm 9 via the sealing material 6 and the heat insulating cylinder base 7. Then, the reaction gas 1 is introduced from the gas introduction port 2a above the furnace core tube 2 and supplied to the wafer 4, and the exhaust gas after the reaction is discharged from the exhaust pipe 10 provided on the lower side wall of the furnace core tube 2. It was a structure.

In such a structure, since only one exhaust pipe 10 is provided laterally, the reaction gas 1
Flow was asymmetric with respect to the central axis of the furnace core tube 2, did not hit the wafer surface uniformly, and adversely affected the in-plane uniformity of film thickness and layer resistance.

In order to improve this, in a thin film vapor deposition apparatus as shown in the longitudinal sectional view of FIG. 3, a susceptor 11 on which a wafer 4 is placed, a shaft 15 for supporting this susceptor, and a pipe surrounding this shaft are provided. The wafer 4 has a pipe 12 mounted via a mounting jig and a shield plate 13 fixed to the pipe, and the wafer 4 is moved into the furnace core tube 2 by a susceptor 11 which moves up and down by a vertically moving mechanism (not shown). It is taken in and out.

The reaction gas 1 is supplied to the wafer 4 from the gas inlet 2a above the furnace core tube 2, the exhaust gas after the reaction is flown into the pipe 12 surrounding the shaft 15, and a plurality of pipes are provided on the lower side wall of the pipe 12. There is known an apparatus for making the flow of the reaction gas 1 in the furnace core tube 2 uniform by uniformly discharging it from the small holes 14 in the furnace to grow a uniform thin film on the wafer 4 (for example, Japanese Utility Model Laid-Open No. 61-192443). Issue). Gases discharged from the plurality of small holes 14 are collected into one and discharged from the exhaust pipe 10 on the lower side wall of the furnace core tube.

[0007]

Among the conventional apparatuses, according to the improved thin film vapor phase growth apparatus as shown in FIG. 3, the gas flow path from the gas inlet 2a of the furnace core tube 2 to the exhaust tube 10 is Since it is not yet axisymmetric, the small hole 14 on the side closer to the exhaust pipe 10 and the small hole 14 on the far side differ in the distance until the reaction gas 1 is discharged from the exhaust pipe 10, and However, there is a problem that the reaction gas 1 is not completely rectified in an axially symmetrical manner.

Since the wafer 4 is taken in and out between the shield plate 13 and the inner wall of the furnace core tube 2, it is necessary to open a gap with a certain margin, so that the reaction gas 1 leaks from this gap. There was a problem that the flow of the reaction gas 1 in the furnace core tube 2 was further disturbed.

[0009]

A semiconductor manufacturing apparatus of the present invention is provided with a vertical furnace core tube for forming a thin film on a wafer surface by a reaction gas and heat. A plurality of exhaust holes for rectifying the gas flow between them are evenly arranged on the heat insulation cylinder base supporting the furnace core tube,
The uniformity of the thin film in the wafer surface is improved.

[0010]

The present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a main part of an embodiment of the present invention. FIG. 1 (a) is a longitudinal sectional view and FIG. 1 (b) is its AA arrow view.

FIG. 1 shows a vertical diffusion furnace in which the opening of the furnace core tube 2 is directed downward. However, since the furnace core tube 2 is not provided with an exhaust port, it is easier to manufacture than before. Since the heat insulating cylinder base 7 is provided with a plurality of exhaust holes 8 evenly arranged on the outer peripheral portion of the portion on which the heat insulating cylinder 5 is mounted, the gas flow in the furnace core tube 2 flows from the gas inlet port 2a to the exhaust tube 10a. Until, it is completely axisymmetric.

Further, at least the outermost peripheral portion of the heat insulating cylinder base 7 is provided with a sealing material 6 so that gas does not leak from between the open end of the furnace core tube 2 and the heat insulating cylinder base 7. Further, one exhaust pipe 10 is connected to the arm 9 that supports the heat insulating cylinder base 7 and moves up and down (the mechanism is not shown) so that the exhaust gas collects at the center of the circular bottom surface of the arm 9. The exhaust gas flow is configured to be more uniform. The plurality of exhaust holes 8 are evenly formed along the circumference between the heat insulation cylinder 5 on the heat insulation cylinder base 7 and the furnace core tube 2, and the arms 9 are also formed so as to overlap these holes. . A protrusion is provided on the heat insulating cylinder base 7 and a recess is provided on the arm 9 so that the arms 9 are fitted to each other so as not to be displaced.

According to the present embodiment, by rectifying the reaction gas in the furnace core tube, the in-plane uniformity of the wafer such as the film thickness and the diffusion layer resistance is improved about twice as much as the conventional one. For example, the in-plane uniformity of the film thickness of 15 nm was 0.3 nm, which was conventionally 0.6 nm due to the difference between the maximum value and the minimum value, but was reduced to 0.3 nm, and the in-plane uniformity was improved.

[0014]

As described above, according to the present invention, a plurality of exhaust holes are evenly arranged in the heat insulating cylinder base that supports the furnace core tube and the heat insulating cylinder, and the exhaust holes are collected into one at the center of the bottom surface of the base and the exhaust pipe , The reaction gas flow becomes completely axially symmetrical with respect to the furnace core tube from the inlet to the outlet of the furnace core tube, and the reaction gas can be rectified and uniformly applied to the wafer surface. .

[Brief description of drawings]

FIG. 1 is a diagram showing a main part of an embodiment of the present invention, in which FIG. 1 (a) is a vertical cross-sectional view and FIG. 1 (b) is its AA arrow view.

2A and 2B are diagrams showing a main part of a conventional semiconductor manufacturing apparatus, wherein FIG. 2A is a vertical cross-sectional view and FIG. 2B is a BB arrow view thereof.

FIG. 3 is a vertical sectional view showing another example of a conventional semiconductor manufacturing apparatus.

[Explanation of symbols]

 1 Reactant Gas 2 Furnace Core Tube 2a Gas Inlet 3 Boat 4 Wafer 5 Heat-insulating Cylinder 6 Sealing Material 7 Heat-insulating Cylinder Base 8 Exhaust Hole 9 Arm 10 Exhaust Pipe 11 Susceptor 12 Pipe 13 Shielding Plate 14 Small Hole 15 Shaft

Claims (3)

[Claims] 1. A semiconductor manufacturing apparatus in which a wafer is housed in a vertical furnace core tube and a thin film is formed on a wafer surface by reaction gas and heat, and a gas flow from a reaction gas introduction side of the furnace core tube to an exhaust side is rectified. A semiconductor manufacturing apparatus characterized in that a plurality of exhaust holes for causing the furnace core tube are evenly arranged on a heat insulation cylinder base supporting the furnace core tube. 2. The semiconductor manufacturing apparatus according to claim 1, wherein the plurality of exhaust holes are arranged between a heat insulating cylinder installed in a central portion of the heat insulating cylinder base and an inner wall of the furnace core tube. 3. The semiconductor manufacturing apparatus according to claim 1, wherein the plurality of exhaust holes are collected in one exhaust pipe at a central portion of an arm on which the heat insulation cylinder base is placed.