JPH06310454A - Hot-wall type heat treatment device - Google Patents

Abstract

(57) [Summary] [Object] To eliminate variations in film thickness or impurity concentration between substrates when performing CVD, oxidation, and diffusion using a semiconductor substrate in a hot wall heat treatment apparatus. [Structure] In addition to an external heater arranged outside the tubular reaction chamber, an internal heater is provided at an intermediate portion and an end portion of each of a plurality of semiconductor substrates to be held horizontally through a heat insulator, and both the external heater and the internal heater are provided. Perform temperature control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a batch type low pressure CVD.
And a hot wall type heat treatment apparatus used for oxidation and diffusion.

[0002]

CV for forming a thin film on a semiconductor substrate
The hot wall type heat treatment device for oxidizing or diffusing the semiconductor substrate D or the semiconductor substrate is a device for heating the semiconductor substrate by using high frequency heating, heater heating, or the like from the outside of the reaction chamber.
FIG. 2 shows a conventional hot wall type heat treatment apparatus by heating a heater. An inner tube 3 is placed in a process tube 2 having an inner diameter of about 250 mm and a height of about 1000 mm surrounded by an outer heater 1 divided into a plurality of zones. A boat 6 for housing the semiconductor substrate 5 is erected on the cap 4 via the cap. The cap 4 is placed on a plurality of heat insulating plates 7 made of silicon carbide (SiC) or quartz that prevent downward heat transfer in order to obtain uniform film formation and heat treatment. The inside of the process tube 2 can be exhausted through the exhaust port 8 and the reaction gas can be introduced through the gas introduction pipe 9. The temperature control of the semiconductor substrate 5 may be profile control in which the temperature profile in the furnace is measured in advance using the thermocouple 10 and the temperature of the external heater 1 at that time is stored through the thermocouple 10 and controlled based on the temperature profile. Alternatively, it is carried out by a cascade control in which the thermocouple 10 is kept in the furnace while being constantly referred to.

[0003]

However, in the above apparatus, since the process tube 2 is heated from outside, it is difficult to control the temperature in detail. In particular, a film with a steep temperature gradient is used to compensate for the non-uniformity of the gas, such as film formation by low pressure CVD using a source gas in which uniformity in the process tube is difficult to obtain, so If you want to get uniformity, you can't do it.

The object of the present invention is to solve the above problems, to enable fine temperature control and to provide a steep temperature gradient,
It is an object of the present invention to provide a hot wall type heat treatment apparatus which can obtain a uniform reaction between substrates to be processed.

[0005]

In order to achieve the above object, the hot wall type heat treatment apparatus of the present invention comprises a plurality of substrates to be treated, which are arranged in a cylindrical reaction chamber whose axial direction is vertical, and between the substrates. An internal heating element is provided at both ends via a heat insulating plate to be held horizontally, and an external heating element is provided so as to surround the cylindrical reaction chamber. It is effective that the substrate to be processed is a semiconductor substrate and the heat insulating plate is made of silicon carbide or quartz.

[0006]

[Function] In addition to the external heating element, by arranging the internal heating element via the heat insulating plate for each of a plurality of substrates to be heated, it is possible to partially raise the temperature, and turbulent flow of gas in the reaction chamber, etc. By this, even when it is difficult to obtain the uniformity of the film thickness or the impurity concentration between the substrates, a steep temperature gradient can be provided in the thin region, and the uniformity of the reaction between the substrates is improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a hot wall type heat treatment apparatus according to an embodiment of the present invention, and the same parts as those in FIG. In this apparatus, an internal heater 11 is arranged in a plurality of stages in a boat 6 in a process tube 2 surrounded by an external heater 1 with a heat insulating plate 12, and a semiconductor substrate 5 is horizontally supported in the middle thereof. . FIG. 3 shows the details of the structure, and the internal heater 11 is held by the frame 61 of the boat 6. The heat insulating plate 12 is made of SiC or quartz. Using this device, based on the internal temperature distribution measured by the thermocouple 10, each zone of the external heater 1 and each internal heater
Control the input to 11 to get a uniform temperature distribution. By changing the number, thickness, and material of the internal heaters 11, it is possible to adjust the temperature range to be controlled.

[0008]

According to the present invention, a hot wall type heat treatment apparatus is provided with an auxiliary heater built into a boat in addition to an external heater, and by controlling it together, a partial temperature rise becomes possible and a steep heat is generated. A gradient can also be formed, which makes it possible to improve the homogeneity of the reaction between the heated substrates, particularly in the film formation on the semiconductor substrate in the gas flow or the oxidation and diffusion.
It can be effectively used for uniforming film formation film pressure or impurity concentration.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a heat treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a conventional hot wall type heat treatment apparatus.

FIG. 3 is a vertical sectional view of a boat portion of the heat treatment apparatus according to the embodiment of the present invention.

[Explanation of symbols]

 1 External Heater 2 Process Tube 4 Cap 5 Semiconductor Substrate 6 Boat 8 Exhaust Port 9 Gas Inlet Pipe 10 Thermocouple 11 Internal Heater 7, 12 Insulation Plate

Claims (4)

[Claims] 1. A cylindrical reaction chamber having a vertical axial direction in which a plurality of substrates to be treated are held horizontally by an internal heating element provided between each of the substrates and at both ends thereof via heat insulating plates. A hot-wall type heat treatment apparatus characterized by comprising an external heating body surrounding the. 2. The hot wall heat treatment apparatus according to claim 1, wherein the substrate to be processed is a semiconductor substrate. 3. The hot wall type heat treatment apparatus according to claim 1, wherein the heat insulating plate is made of silicon carbide. 4. The heat insulating plate is made of quartz.
The hot wall type heat treatment apparatus described.