JPH10201U - Semiconductor manufacturing equipment - Google Patents

Abstract

[PROBLEMS] To reduce contamination of a semiconductor substrate by a reaction product. SOLUTION: An exhaust pipe 9 is provided at a closed end of a reaction tube 8 having one end opened and the other end closed, and the exhaust pipe 9 is placed inside the heating furnace 1 along the reaction tube 8 near the open end. The reaction gas outlet 9b is provided.

Description

[Detailed description of the invention]

[0001]

[Industrial applications]

 The present invention relates to an apparatus for manufacturing a semiconductor device, and more specifically to an apparatus for performing a chemical reaction process such as thermal oxidation, diffusion, and vapor phase growth (hereinafter, simply referred to as “semiconductor manufacturing apparatus”).

[0002]

[Prior art]

 In processing steps such as thermal oxidation, diffusion, and vapor phase growth in the manufacturing process of a semiconductor device such as an LSI, a semiconductor substrate is inserted into a heated reaction tube and a predetermined reaction gas is introduced to perform the processing. In the case of a conventional semiconductor manufacturing apparatus as shown in FIG. 5 (an example of a vertical type), the reaction products deposited on the inner wall of the reaction tube 8 near the reaction gas outlet 9b are likely to peel off. When the semiconductor substrate 3 is taken in and out of the heating furnace 1 together with the holder 2 supported by the support table 4, there is a problem that the separated reaction products adhere to the semiconductor substrate 3 and become contaminated. In FIG. 5, reference numeral 1a denotes a furnace body, 1b denotes a heater, 6 denotes a rotary drive mechanism for rotating the support table 4, 7 denotes a vacuum flange, and 10 denotes an inlet for a reaction gas g. On the other hand, recently, as shown in FIG. 6, the reaction tube 8 is doubled, and the inlet / outlet of the semiconductor substrate (not shown) and the reaction gas outlet 9b are separated to solve the above problem. Since the heavy reaction tube 8 is used, there is a disadvantage that the apparatus is complicated and expensive. Further, the work of removing such a complicated and large-sized reaction tube 8 from the heating furnace 1 for cleaning was extremely difficult.

[0003]

[Problems to be solved by the invention]

 An object of the present invention is to eliminate the above-mentioned drawbacks of the conventional semiconductor manufacturing apparatus and to provide a simple and inexpensive semiconductor manufacturing apparatus with less contamination of the semiconductor substrate by reaction products.

[0004]

In order to achieve the above-mentioned object, in a semiconductor manufacturing apparatus of the present invention, an exhaust pipe is provided at a closed end of a reaction tube whose lower end is open and whose upper end is closed. An exhaust port is provided in the inner space of the exhaust pipe heating furnace along the reaction tube to the vicinity of the open end. In this case, the reaction gas is introduced from the reaction gas inlet provided at the lower end of the reaction tube, and is exhausted by making a U-turn in the soaking space created by the heating furnace. The reaction gas is discharged from the upper end side, which has a relatively high temperature and forms a soaking space, but in this region, a reaction product with a small temperature change and uniform film quality is formed. Difficult to peel off from the tube wall. On the other hand, since the temperature decreases near the exhaust port and a temperature change occurs, a reaction product having a non-uniform film quality is formed, and the reaction product is easily separated from the tube wall. However, in the structure of the present invention, this part is far away from the exhaust pipe outlet, and is completely separated from the semiconductor substrate inlet (open end of the reaction tube). Is extremely small. As described above, according to the present invention, the same effect can be obtained as when a simple and inexpensive single tube is used and a double tube is used (FIG. 6).

Further, by providing an electrode for plasma generation on the outer peripheral wall of the reaction tube and applying a high frequency voltage, plasma cleaning can be performed without removing the reaction tube from the heating furnace. However, at this time, the pressure inside the reaction tube must be reduced by evacuation. By inserting the electrode into a sheath such as a quartz tube, it is possible to prevent a short circuit between the electrode tube and the electrode and the heater tube, and to make sure that the electrode is in close contact with the reaction tube. Further, by introducing an inert gas such as nitrogen through a thin tube from one end of the sheath, it is possible to prevent the electrode material, for example, the electrode material such as isotropic carbon which has been covered with SiC from being oxidized and consumed.

[0006]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In the drawings, the same members as those in FIGS. 5 and 6 are denoted by the same reference numerals. An exhaust pipe outlet 9a is provided at the closed upper end 8a of the reaction tube, and the exhaust pipe 9 is routed and arranged in the soaking space of the heating furnace 1 to the vicinity of the lower end 8b opened along the reaction tube 8. A reaction gas outlet 9b is provided there. In this case, the reaction gas g is discharged from the upper end 8a, which has a relatively high temperature and forms a soaking space, but in this region, a reaction product having a small temperature change and uniform film quality is formed. Therefore, it is difficult to peel off from the tube wall. On the other hand, the vicinity of the reaction gas discharge port 9b far from the exhaust pipe outlet 9a is not a uniform heating space, but a temperature change occurs. As a result, a reaction product having uneven film quality is formed, and separation from the pipe wall is caused. Is more likely to occur. However, in the structure of the present invention, this portion is far away from the exhaust pipe outlet 9a and completely separated from the semiconductor substrate insertion port (open end of the reaction tube). The possibility of adhesion is extremely low.

The exhaust pipe 9 provided along the reaction tube 8 is preferably fixed to the reaction tube 8 by fusion or the like for stability. Although the above embodiment has been described with reference to a vertical furnace, it can be similarly applied to a horizontal furnace.

FIGS. 1 and 2 show examples of the arrangement of electrodes 11 for plasma cleaning of a reaction tube. These electrodes are housed in a sheath 12 and connected to a high-frequency power supply 13 to which a high-frequency voltage is applied. At this time, if the inside of the reaction tube 8 is in a sufficiently reduced pressure state, plasma is generated and the inside of the reaction tube is cleaned. In the connection example of FIG. 2, voltages of opposite polarities are applied to adjacent electrodes, and therefore, plasma is generated between the adjacent electrodes, which is convenient for cleaning the inner wall of the reaction tube.

In the above embodiments, rod-shaped electrodes are shown, but plate-shaped or net-shaped electrodes can also be applied. In order to exhaust the gas from several places in order to obtain the optimum flow of the reaction gas, it is possible to take out the exhaust pipe as shown in FIG. 3 (like a fluorescent tube) or FIG. 4 (like a quadruple).

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment in which the present invention is applied to a vertical furnace,

FIG. 2 is an upper plan view showing one connection when a plasma electrode is provided,

FIG. 3 shows an example in which a fluorescent tube-like exhaust pipe outlet is provided at the upper end of the reaction tube.

FIG. 4 is an example in which a quadruple-like outlet is provided.

FIG. 5 shows an example using a conventional single reaction tube,

FIG. 6 is an example using a conventional double reaction tube.

[Explanation of symbols]

 1. . . . Heating furnace 1a. . . Furnace body 1b. . . Heater 2. . . . Semiconductor substrate holder 3. . . . Semiconductor substrate 4. . . . Support base 5. . . . Support shaft 6. . . . Rotation drive mechanism 7. . . . Vacuum flange 8. . . . Reaction tube 8a. . . Closed top of reaction tube 8b. . . 8. Open bottom of reaction tube . . . Exhaust pipe 9a. . . Exhaust pipe outlet 9b. . . Reactive gas outlet 10. . . . Reaction gas inlet 11. . . . Plasma electrode 12. . . . Sheath 13. . . . High frequency power supply g. . . . Reaction gas OR. . . O-ring

Claims (2)

[Utility model registration claims] 1. A semiconductor manufacturing apparatus comprising: a reaction tube having an inlet and an outlet for a reaction gas; and a heating furnace covering a side surface of the reaction tube, wherein one end is opened and the other end is closed. An exhaust pipe is provided at a closed end of the reaction tube, and the exhaust pipe is routed inside the heating furnace along the reaction tube to near the open end, and an exhaust port for the reaction gas is provided. A semiconductor manufacturing apparatus characterized by the above-mentioned. 2. The semiconductor manufacturing apparatus according to claim 1, wherein an electrode for generating plasma inside said reaction tube is disposed on an outer peripheral wall of said reaction tube.