JPH03112132A - Low pressure type short time heat treatment device - Google Patents

Abstract

PURPOSE:To make uniform the temperature distribution in a semiconductor substrate surface by providing the semiconductor substrate at a right angle with a gas flow and providing a disc-like straightener which transmits infrared rays in the upper stream of the substrate and in parallel with the substrate. CONSTITUTION:A semiconductor substrate 11 is held by a boat so as to become coaxial with a cylindrical reactor core tube 12. In this case, the substrate 11 is taken in the boat so that its surface to be treated is faced toward the upper stream side of the flow of a gas 14. In the boat 13, a disc-like straightener 16 which transmits infrared rays irradiated from a lamp 15 is provided at a place being on the upper stream side of the substrate 11, so that it is in parallel with the substrate 11 and becomes coaxial with the reactor core tube 12. The back surface 21a of the substrate 11 is heated directly by infrared rays 25 irradiated from the lamp 15. On the other hand, since a surface to be treated 21 of the substrate 11 is heated by infrared rays 26 transmitted through the commutating plate 16, the substrate 11 is heated uniformly. Since the flow in the space between the surface to be treated 21 of the substrate 11 and the straightener 16 becomes a turbulent flow 24, the temperature unevenness in the surface to be treated of the substrate 11 can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a short-time heat treatment apparatus that performs heat treatment using a lamp under reduced pressure.

[Conventional technology]

Conventionally, a short-time heat treatment apparatus for electrically activating implanted ions has a semiconductor substrate 1 installed inside a cylindrical furnace core tube 32, as shown in FIGS. 3(a) and 3(b).
1 is heat-treated by irradiating the outside of the furnace core tube with a lamp 15 in an atmospheric gas 14 such as argon or nitrogen gas, and the semiconductor substrate 11 is placed on a support stand 35 so as to be parallel to the flow of gas 14. is held horizontally through the

[Problem to be solved by the invention]

However, in the short-time heat treatment apparatus having the above structure, when the semiconductor substrate 11 is heat-treated for a short time in the atmospheric gas 14, the semiconductor substrate 11 is heated due to the laminar flow created by the flow of the gas 14.
A stagnation layer of different thickness is formed on the surface of the Since there is almost no movement of gas in this stagnant layer, no cooling effect due to the gas can be expected, and therefore a temperature distribution depending on the thickness of the stagnant layer appears within the substrate surface. Therefore, the temperature of the thicker part of the stagnant layer is higher and the temperature of the thinner part is lower, resulting in non-uniform temperature within the plane, and for example, the electrical activation rate of implanted ions varies greatly within the substrate plane. There was a problem.

The present invention has been made in order to solve the conventional problems as described above, and provides a short-time heat treatment apparatus that can suppress temperature non-uniformity within the substrate surface due to the laminar flow created by the gas flow. It's about doing.

[Means to solve the problem]

In order to achieve the above object, a reduced pressure type short time heat treatment apparatus according to the present invention is a short time heat treatment apparatus that performs heat treatment using a rung under reduced pressure. A disk-shaped rectifying plate that transmits infrared rays is placed on the semiconductor substrate with the surface to be processed facing upstream, and a cylindrical furnace core tube is installed on the upstream side of the semiconductor substrate and parallel to the substrate. It was installed coaxially with the

[Effect]

The reduced-pressure short-time heat treatment apparatus of the present invention is installed perpendicular to the gas flow at a position where the semiconductor substrate is coaxial with a cylindrical furnace tube under reduced pressure, and an infrared ray is provided upstream of the semiconductor substrate. The semiconductor substrate is heat-treated by heating it with a lamp by installing a disc-shaped rectifying plate that transmits the irradiation gas at a position parallel to the semiconductor substrate and coaxial with the cylindrical furnace core tube.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1(a) and 1(b) are schematic diagrams of an embodiment of the present invention. 3(a) shows a front sectional view, and FIG. 2(b) shows a top sectional view.

As shown in FIG. 1, a semiconductor substrate 11 is connected to a cylindrical furnace core tube 1.
It is held on a boat 13 so as to be coaxial with 2. At this time, the semiconductor substrate 11 is mounted on the boat 13 so that the surface to be processed faces the upstream side of the flow of the gas 14.

The boat 13 has a disc-shaped rectifying plate 16 made of, for example, quartz glass that transmits infrared rays emitted from the lamp 15, and the rectifying plate 16 has the same diameter as the substrate 11.
The rectifying plate 16 is arranged parallel to the semiconductor substrate 11 and coaxially with the cylindrical furnace core tube 12 on the upstream side of the semiconductor substrate 11 . Incidentally, the scum is introduced through the gas intake port 17 and is discharged from the vacuum exhaust port 18 by a vacuum pump.

In the embodiment, as shown in FIG. 2, the back surface 21a of the semiconductor substrate 11 is directly heated by infrared rays 25 irradiated from the lamp 15. On the other hand, the heat-treated surface 21 of the semiconductor substrate 11 is heated by the infrared rays 26 irradiated from the lamp 15 and transmitted through the rectifying plate 16, so that the semiconductor substrate 11 is uniformly heated. The semiconductor substrate 11 is installed so that the gas flow in the space created by the heat-treated surface 21 of the semiconductor substrate 11 and the rectifier plate 26 is perpendicular to the flow of the gas 14.
and a rectifying plate 26 installed parallel to this semiconductor substrate 11.
Since the pressure inside the furnace core tube 12 between the two substrates is reduced, a turbulent flow 24 occurs, and a stagnation layer of different thickness due to the laminar flow is not formed on the heat-treated surface 21, so that temperature non-uniformity within the substrate surface can be avoided.

〔Effect of the invention〕

As is clear from the above, according to the present invention, the semiconductor substrate is installed perpendicular to the gas flow at a position coaxial with the cylindrical furnace core tube under reduced pressure, and the semiconductor substrate is placed on the upstream side of the semiconductor substrate. By installing a disc-shaped rectifying plate that transmits infrared rays in parallel and coaxially with the cylindrical furnace core tube, the generation of laminar flow, which is the cause of the formation of a stagnation layer, can be avoided. Since a turbulent flow is generated, the temperature distribution within the semiconductor substrate surface becomes uniform even when heated by a lamp, which has the effect of making device characteristics uniform within the substrate surface.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are schematic diagrams showing one embodiment of the present invention, FIG. 2 is a conceptual diagram showing a heat treatment state in the present invention, and FIG. 3(a) is a front sectional view showing a conventional example. , Figure 3 (b
) is a top sectional view of the same. 11...Semiconductor substrate 12...Cylindrical furnace core tube 13...Boat 14...Gas 15...
・Lamp 16... Rectifier plate 17... Gas inlet 18... Vacuum exhaust port 24... Turbulent flow
25.26...Infrared rays (α) (b) Figure 1 shows the surface to be heat treated in Figure 2.

Claims (1)

[Claims] (1) In a short-time heat treatment apparatus that performs heat treatment using a lamp under reduced pressure, a semiconductor substrate is installed in a cylindrical furnace core tube coaxially with the furnace core tube, and the surface to be processed of the semiconductor substrate is placed on the upstream side. A reduced-pressure short-time heat treatment characterized in that a disc-shaped rectifying plate that transmits infrared rays is placed upstream of the semiconductor substrate, parallel to the substrate, and coaxial with the cylindrical furnace core tube. Device.