JP2859164B2 - Semiconductor device manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing apparatus, and more particularly to a horizontal diffusion furnace for oxidizing and diffusing a semiconductor substrate.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional diffusion furnace used in a manufacturing process of a semiconductor device is provided with a furnace core tube 1 having a gas inlet 4A at one end, and provided around the furnace core tube 1. A semiconductor substrate 2 placed on a quartz boat 3 is inserted into a furnace core tube 1 heated at a high temperature through a furnace port 5, and a gas such as oxygen or nitrogen is introduced through a gas inlet port 4A. Was introduced, and treatments such as oxidation and diffusion were performed.

[0003]

However, since the conventional diffusion furnace has a gas inlet 4A at the center of the diameter of the furnace core tube, the gas introduced into the furnace core tube is heated to a high temperature and the furnace core is heated. Since the gas concentration rose to the upper part of the tube, the gas concentration became non-uniform in the furnace, and the heat treatment amount of the semiconductor substrate 2 varied in the plane and in the batch. This variation in the amount of heat treatment causes, for example, variation in the thickness of the gate oxide film and the like, leading to a decrease in the yield of the semiconductor device.

In order to solve this problem, for example, Japanese Unexamined Patent Publication No.
In Japanese Unexamined Patent Publication No. 1-239622, for the purpose of uniformly diffusing impurities into a semiconductor substrate, as shown in FIG. 4, a gas inlet 4B is installed at a position eccentric from the center of the diameter of the furnace core tube 1A. A propeller-shaped gas stirring blade 7 having a rotating mechanism is installed at a position until the semiconductor wafer 2A reaches the semiconductor substrate 2A to stir the gas to perform uniform impurity diffusion.

[0005] However, this method not only increases the cost due to the complicated structure of the apparatus, but also causes problems such as the generation of dust due to the rotation mechanism in the furnace core tube, which adversely affects the semiconductor substrate.

An object of the present invention is to provide a semiconductor device manufacturing apparatus capable of making the gas concentration in a furnace core tube more uniform without complicating the structure of the apparatus.

[0007]

A semiconductor device manufacturing apparatus according to the present invention is characterized in that a gas inlet is provided below the end of the furnace core tube. The gas introduced from the lower part of the furnace core tube is heated in the furnace core tube and flows toward the furnace port while rising to the upper part of the furnace core tube. Thereby, the gas concentration in the furnace is made uniform, and a uniform heat treatment can be obtained on the semiconductor substrate.

[0008]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a first embodiment of the present invention.

Referring to FIG. 1, the manufacturing apparatus includes a furnace core tube 1.
And a gas inlet 4 provided below the end of the furnace core tube 1 and a heater 6 provided around the furnace core tube 1. Hereinafter, a case where the semiconductor substrate is heat-treated using this apparatus will be described.

First, the quartz boat 3 loaded with the semiconductor substrate 2 is inserted into the furnace core tube 1 heated by the heater 6 at a high temperature. Next, desired gas (oxygen, nitrogen, etc.) from gas inlet 4
Is introduced. In this state, heat treatment is performed for a predetermined time while evacuating from the furnace port 5 side. At this time, in the conventional diffusion furnace shown in FIG. 3, since the gas inlet 4A is located at the center of the diameter of the end of the furnace core, the introduced gas is heated in the furnace core and rises to the upper part of the furnace core. The gas concentration increases in the upper portion of the semiconductor substrate 2 and the variation in the heat treatment amount such as the oxide film thickness variation increases. On the other hand, in the diffusion furnace according to the present embodiment, the gas inlet 4 is located below the furnace tube end. Therefore, the gas introduced into the furnace core tube 1 is drawn toward the furnace port 5 while rising upward. For this reason, the gas concentration becomes uniform inside the furnace core tube 1, and the heat treatment amount of the semiconductor substrate 2 becomes uniform. As a result, the film thickness uniformity of the gate oxide film and the like are improved, and an improvement in the yield as a semiconductor device can be expected.

FIG. 2 is a front view of a second embodiment of the present invention, showing an end of a furnace tube having a gas inlet. The second embodiment is the same as the first embodiment shown in FIG. 1 except that a pair of gas inlets 4 and 4 are provided below the end of the furnace core tube 1.

In the second embodiment, since a pair of gas inlets 4 and 4 are provided at the lower portion of the end of the furnace core tube, the gas concentration to be introduced is controlled not only in the vertical direction in the furnace core tube but also in the horizontal direction. Since it can be made uniform in the direction, there is an advantage that the in-plane uniformity such as the diffusion amount of the semiconductor substrate 2 can be further improved. It is needless to say that the number of gas inlets may be two or more.

[0013]

As described above, according to the present invention, by providing the gas inlet of the diffusion furnace at the lower portion of the end of the furnace tube, the gas concentration in the furnace tube is made uniform, and the heat treatment amount of the semiconductor substrate is reduced. There is an effect that uniformity can be improved. As a result, the yield of the semiconductor device can be improved.

[Brief description of the drawings]

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

FIG. 2 is a front view of a second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing an example of the related art.

FIG. 4 is a sectional view showing another example of the prior art.

[Explanation of symbols]

 1, 1A Furnace tube 2, 2A Semiconductor substrate 3, 3A Quartz boat 4, 4A, 4B Gas inlet 5 Furnace 6 Heater 7 Stirrer blade

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-52-42075 (JP, A) JP-A-59-41842 (JP, A) JP-A-51-38870 (JP, A) JP-A 50-420 81677 (JP, A) Japanese Utility Model Showa 52-112772 (JP, U) Japanese Utility Model Utility Model 2-36033 (JP, U) Japanese Utility Model Utility Model 4-4738 (JP, U) Japanese Utility Model Utility Model 4-131656 (JP, U) JitsuHiraku Akira 55-111343 (JP, U) Tokuoyake Akira 47-30595 (JP, B1) Tokuoyake Akira 50-18470 (JP, B1) (58 ) investigated the field (Int.Cl. ^6, DB name) H01L 21/22 H01L 21/31

Claims (2)

(57) [Claims] (1) A gas is directly injected into a furnace core tube at a closed end.
It has a horizontal furnace core tube having a gas inlet for introduction , the other end of which is open, and a heater provided around the furnace tube. A semiconductor substrate is put in the furnace tube, and oxidation and impurity diffusion are performed. A semiconductor device manufacturing apparatus according to claim 1, wherein said gas inlet is provided at a lower portion of an end portion of said furnace tube. 2. The semiconductor device manufacturing apparatus according to claim 1, wherein a plurality of gas inlets are provided.