JPH08203795A - Reaction furnace for semiconductor manufacture - Google Patents

Abstract

PURPOSE: To prevent a film from attaching to a protection tube of a furnace temperature detector for detecting a furnace temperature in a reaction furnace for semiconductor manufacturing. CONSTITUTION: A protection tube 7 wherein a furnace temperature detector 8 is contained is inserted into a reaction tube 2 removably, or a protection tube with a heater temperature detector 6 and a furnace temperature detector 8 wherein a furnace temperature detector is contained is inserted into a reaction tube removably for furnace temperature control based on a detected temperature of a heater temperature detector by adopting a detected temperature of a heater temperature detector before removal of a furnace temperature detector as a desired value. At first, a furnace temperature is controlled with a furnace temperature detector inserted and then, film formation processing is performed by introducing reaction gas into a reaction tube with a furnace temperature detector removed from a reaction tube, or, a temperature is controlled so that a detected temperature from a heater temperature detector during film formation processing becomes a desired value set before a furnace temperature detector is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing reaction furnace, and more particularly to a semiconductor manufacturing reaction furnace with improved accuracy in detecting the temperature inside the furnace.

[0002]

2. Description of the Related Art One of the processes of a semiconductor manufacturing apparatus is diffusion of impurities in a silicon wafer or formation of a thin film by chemical vapor deposition. These steps are carried out by loading a wafer into a reaction furnace and introducing a reaction gas while maintaining a predetermined temperature.

A conventional reaction furnace for semiconductor production will be described with reference to FIG.

A reaction tube 2 is provided in an upright hollow heater 1, and an inner tube 3 having an open upper end is concentrically provided in the reaction tube 2. A reaction gas supply pipe 4 is connected to the lower end of the inner pipe 3, and an exhaust pipe 5 is connected to the lower end of the reaction pipe 2. Heater temperature detectors 6 are provided penetrating the heater 1 at required intervals along the axial direction of the heater 1. The temperature detection point of the heater temperature detector 6 is located near the outer surface of the heater 1, and the temperature is detected by the radiant heat from the inside of the heater 1. A protection tube 7 is inserted along the inner tube 3 inside the heater 1, and a plurality of furnace temperature detectors 8 are provided in the protection tube 7. 8 detects the temperature at a plurality of points along the axial direction.

A boat 10 loaded with a large number of wafers 9 is loaded in the inner tube 3, and the boat 10 is raised and lowered via a boat support 11. .

The wafer 9 is treated by the exhaust pipe 5 through the reaction tube 2 while being heated to a predetermined temperature by the heater 1.
After the inside is evacuated, the reaction gas is introduced from the reaction gas supply pipe 4 to perform the operation.

Since the temperature in the furnace during the heat treatment greatly affects the film forming quality such as film forming rate, film uniformity, and reproducibility, the heater temperature detector 6 detects the temperature in the vicinity of the heater 1 and the temperature in the furnace. The temperature in the vicinity of the wafer 9 is detected by the container 8, and zone control of the heating state of the heater 1 is performed so that the temperature of the wafer 9 is maintained at a predetermined temperature, and the temperature inside the furnace is controlled. It is preferable that the temperature control in the furnace is detected at a position as close as possible to the wafer 9 as the object to be processed in order to improve accuracy. As described above, the temperature detector 8 in the furnace is used in addition to the heater temperature detector 6. The temperature is detected by being inserted into.

[0008]

However, the wafer 9
When the film is formed on, the reaction product is also deposited on the protective tube 7 in the furnace, and a film is formed on the surface. This film blocks radiant heat or reduces the rate of heat transfer to the in-furnace temperature detector 8 housed therein, so that the thermal response is reduced. Therefore, a temperature difference or a time lag is generated between the detected temperature and the actual temperature to reduce the accuracy of temperature control, and the wafer processing reproducibility,
There is a problem that it adversely affects the uniformity of quality.

[0009]

According to the present invention, a protection tube accommodating a temperature detector in a furnace can be inserted into and removed from a reaction tube,
Alternatively, the temperature inside the furnace is controlled on the basis of the temperature detected by the heater temperature detector with the temperature detected by the heater temperature detector before removal of the furnace temperature detector as a target value.

[0010]

The temperature inside the furnace before the wafer processing is controlled based on the temperature detector in the furnace to a predetermined temperature, and the protection tube is pulled out from the reaction tube during the wafer processing. Therefore, the film does not adhere to the protective tube, and the temperature can be measured accurately and without a time lag.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the same parts as those shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

An elevating mechanism 12 is provided below the reaction tube 2 in parallel with the axis of the reaction tube 2, an elevating table 13 is provided in the elevating mechanism 12, and the elevating table 13 is parallel to the axis of the reaction tube 2. Moreover, the protection pipe 7 located between the reaction pipe 2 and the inner pipe 3 is erected.
A required number of in-furnace temperature detectors 8, for example, thermocouples are inserted in the protective tube 7 to detect temperatures at a plurality of positions along the axis of the protective tube 7. A hole through which the protection tube 7 penetrates is formed in the bottom surface of the reaction tube 2, and a bellows 14 for accommodating the protection tube 7 is provided between the bottom surface of the reaction tube 2 and the elevating table 13 and the bellows 14 is provided. Is the protection tube 7
It expands and contracts in accordance with the vertical movement of the protective tube 7 to make the penetrating portion of the protective tube 7 of the reaction tube 2 airtight.

The boat 10 is loaded into the reaction tube 2 and the elevating mechanism 12 raises the elevating table 13, the furnace temperature detector 8 is loaded into the furnace, and the heater 1 heats the reaction tube 2 inside. To do. The temperature is detected by the heater temperature detector 6 and the furnace temperature detector 8, the heater 1 is controlled, the inside of the furnace is heated to a predetermined temperature, and when the heating state is stable, the elevating mechanism 12 is driven. The in-furnace temperature detector 8 is lowered via the lift 13 and the reaction gas is introduced from the reaction gas supply pipe 4 to perform the film forming process on the wafer 9.

The temperature control after lowering the furnace temperature detector 8 is performed based on the temperature detection value of the heater temperature detector 6, and the temperature control of the heater temperature detector 6 immediately before the furnace temperature detector 8 is lowered. The temperature is stored, and the stored detection value of the heater temperature detector 6 becomes the target value for the heater 1 temperature control.

The conditions under which the film adheres must be a predetermined temperature or higher, and is 400 ° C. or higher when the reaction gas is SiH ₄ , for example. Since the protective tube 7 is removed from the heater 1 and is located outside the furnace in the state where the reaction gas is supplied, the temperature is sufficiently lower than 400 ° C. and no film is attached. Therefore, the temperature detection of the in-furnace temperature detector 8 is not affected by the attached film, and accurate temperature detection without time lag is possible and there is no change with time.

In the above embodiment, the semiconductor manufacturing reaction furnace having the vertical furnace is described, but it goes without saying that the present invention can be applied to the semiconductor manufacturing reaction furnace having the horizontal furnace.

[0018]

As described above, according to the present invention, the temperature detection by the furnace temperature detector is accurate, there is no time lag,
Also, since there is no change over time, the temperature control accuracy is improved,
Further, it exhibits excellent effects such as improved reproducibility.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

 1 Heater 2 Reaction Tube 3 Inner Tube 6 Heater Temperature Detector 7 Protective Tube 8 Furnace Temperature Detector 9 Wafer 12 Lifting Mechanism 13 Lifting Table 14 Bellows

Claims (2)

[Claims] 1. A reaction furnace for semiconductor manufacturing, wherein a protection tube accommodating a temperature detector in the furnace can be inserted into and removed from the reaction tube. 2. In a reaction furnace for semiconductor manufacturing, comprising a heater temperature detector and an in-furnace temperature detector, a protection tube accommodating the in-furnace temperature detector can be inserted into and removed from the reaction tube. A reactor for semiconductor manufacturing, characterized in that the temperature inside the furnace is controlled based on the temperature detected by the heater temperature detector, with the temperature detected by the heater temperature detector before removal of the inner temperature detector as a target value.