JPH02294024A - Diffusion furnace - Google Patents

Abstract

PURPOSE:To suppress the fluctuation of the temperature inside a furnace-core tube so that impurity diffusion can be performed uniformly into a wafer by providing thermocouples for controlling the temperature inside the furnace-core tube when impurities are diffused into the wafer in a quartz board. CONSTITUTION:When no quartz board 2 exists in a furnace-core tube 1, the temperature inside the tube 1 is controlled by means of a rear-heater, central- heater, and front-heater thermocouples 7, 8, and 9. When the quartz board 2 is inserted into the tube 1, the thermocouples 7, 8, and 9 are switched to a rear, central, and front thermocouples 13, 14, and 15 in the board 2 by means of a thermocouple switch 16 and the temperature inside the tube 1 is controlled. Thus the temperature inside the tube 1 can be controlled by means of the thermocouples 13, 14, and 15 incorporated in the board 2 when the board 2 is inserted into the tube 1. Therefore, the temperature inside the tube 1 becomes uniform and the diffused quantity of impurities into a wafer 3 hardly fluctuates.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a diffusion furnace apparatus used in the manufacturing process of semiconductor devices.

[Conventional technology]

Conventionally, this type of diffusion furnace apparatus, as shown in FIG. 3, has thermocouples 7,8.
It was configured to control the temperature inside the furnace core tube.

[Problem to be solved by the invention]

The conventional diffusion furnace device described above is configured to control the temperature inside the furnace core tube using a thermocouple built into the heater section, so the temperature within the furnace core tube fluctuates during diffusion.
This fluctuation tendency sometimes becomes noticeable at both ends of the furnace core tube, resulting in variations in the amount of impurities diffused into the semiconductor substrate (hereinafter referred to as wafer).

The present invention differs from the conventional diffusion furnace apparatus described above in that, in addition to the conventional thermocouple, a thermocouple is built into the quartz boat that holds the wafer in order to control the temperature inside the furnace core tube during diffusion. have. [Means for Solving the Problems] A diffusion furnace apparatus of the present invention includes a quartz boat on which a semiconductor substrate is placed, a furnace core tube into which the quartz boat is placed, a heater for heating the furnace core tube, and the furnace core tube. In a diffusion furnace apparatus having a temperature controller for controlling the temperature inside the core tube, a thermocouple for controlling the temperature inside the furnace core tube during impurity diffusion is built into the quartz boat.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic sectional view of the first embodiment of the present invention. A rear thermocouple 13, a center thermocouple 14, and a front thermocouple 15 are built into the quartz boat 2 that holds the wafer 3.
are connected to the rear temperature controller 10 via the thermocouple switch 16 together with the rear heater thermocouple 7 in the rear heater 4, the center heater thermocouple 8 in the center heater 5, and the front heater thermocouple 9 in the front heater 6.
, a center temperature controller 11, and a front temperature controller 12. If there is no quartz boat 2 in the furnace core tube 1, the rear heater thermocouple 7, center heater thermocouple 8, and front heater thermocouple 9
Control the temperature inside.

On the other hand, when the quartz boat 2 is inserted into the furnace core tube 1, the thermocouple switch 16 switches the quartz boat 2 into the furnace core tube 1.
3. Switch to the center thermocouple 14 and front thermocouple 15 to control the temperature inside the furnace core tube 1.

As described above, according to the first embodiment, the temperature inside the furnace core tube 1 when the quartz boat 2 is placed inside the furnace core tube 1 can be controlled by the thermocouple built into the quartz boat 2. The temperature inside the core tube 1 becomes uniform, and the variation in the amount of impurity diffusion in the wafer 3 becomes extremely small.

FIG. 2 is a side view of a quartz port in a second embodiment of the invention. The quartz hole 2A is provided with a convex portion 17, and a rear thermocouple 13, a center thermocouple 14, and a front thermocouple 15 built into the convex portion 17 cause the first
Temperature control is performed in the same manner as in the embodiment.

In this second embodiment, since the thermocouples 13, 14, and 15 are built into the convex portion 17, there is an advantage that the temperature inside the furnace core tube 1 can be controlled more uniformly.

〔Effect of the invention〕

As explained above, the present invention has a thermocouple built into the quartz boat, so that when the quartz boat is inside the furnace core tube, the temperature inside the furnace core tube can be controlled by the thermocouple built into the quartz boat. This has the effect of suppressing temperature fluctuations within the furnace core tube and uniformly diffusing impurities into the wafer.

10... Rear temperature controller, 11... Center temperature controller, 12... Front temperature controller, 13... Rear thermocouple, 14... Center thermocouple, 15... Front thermocouple, 16... ...Thermocouple switch, 17...Convex part.

Claims (1)

[Claims] A diffusion furnace device comprising a quartz boat on which a semiconductor substrate is placed, a furnace core tube into which the quartz boat is placed, a heater for heating the furnace core tube, and a temperature controller for controlling the temperature inside the furnace core tube. A diffusion furnace apparatus characterized in that a thermocouple for controlling the temperature inside the furnace core tube during impurity diffusion is built into the quartz boat.