JPH0344026A - Heat treatment apparatus - Google Patents

Abstract

PURPOSE:To prevent heat radiation from a furnace port of a heat treatment apparatus, minimize air enfoldment into a quartz tube and improve oxide film characteristics by providing a quartz cap for closing an opening of the quartz tube immediately after a diffusion board is put into the quartz tube of a furnace body. CONSTITUTION:When a cantilever holding part 18 is moved to put a diffusion board 14 into a quartz tube 12, a quartz cap 15 completely closes a furnace port. While the diffusion board 4 is further being moved te put the diffusion board 14 to the center of the quartz tube 12, a spring 20 is stretched with the quartz cap 15 keeping the furnace port closed. Since the quartz cap 15 is held by a cantilever 16 and a slide bearing of the cantilever holding part 18, it is fixed in stable state. Conversely, when the diffusion board 14 is to be removed, the quartz cap is fixed to keep the furnace closed until the diffusion board comes out of the furnace port.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is used in a heat treatment apparatus for heat treating a semiconductor substrate, and more specifically, when the semiconductor substrate is loaded into and taken out from the heat treatment apparatus. It relates to the structure of a lid that is attached to a cantilever or a lever for soft landing.

2. Description of the Related Art Conventionally, as a heat treatment apparatus for semiconductor substrates, there has been a cantilever type as a diffusion boat loading type.

As a conventional technique, an example of this one-cantilever type is shown in a side sectional view in FIG. In FIG. 2, heat treatment is performed by placing a semiconductor substrate 3 into a quartz tube 2 set inside a heater 1. The semiconductor substrate 3 is set in a diffusion boat 4 made of quartz or SiC, placed on a cantilever 6 supported by a quartz cap 5, and heat-treated by the movement of the candelver 6. The movement of the cantilever 6 was controlled by moving the cantilever holding part 8 along the rail 7.

A quartz cap 5 connected to a cap holding shaft 9 is fixed to the cantilever holding part 8 , and when the diffusion boat 4 is set in the center of the quartz tube 2 , the quartz cap 5 is fixed to the cantilever holding part 8 . There was a structure that just put a lid on the furnace opening.

Problems to be Solved by the Invention In such a conventional configuration, the time required for the diffusion boat to be set in the center of the quartz tube and the quartz cap to cover the furnace mouth is approximately 5 cm/min at the speed of the boat. It's so slow that it takes about 30 minutes.

For this reason, the heat release from the furnace mouth side of the heat treatment furnace is large.
There was a problem that the temperature suddenly dropped when the diffusion boat was introduced. Furthermore, more importantly, semiconductor substrates are placed into the heat treatment furnace without a lid, so even if the semiconductor substrate is quartz. - Even if a large amount of inert scum is flowed into the furnace, there is a major problem in that air is drawn in from the furnace mouth, resulting in non-uniform film thickness and adverse effects on device characteristics.

The present invention solves these problems by preventing heat radiation from the heat treatment furnace mouth, minimizing the entrainment of air into the quartz duplex, improving the uniformity of the film thickness, and improving the oxide film properties. It is an object of the present invention to provide a heat treatment apparatus that can easily realize the second aspect.

Means for Solving the Problems In order to solve this problem, the present invention provides that when a diffusion boat having a holding shaft is used as a lid of a heat treatment furnace and moves inside the heat treatment furnace, this lid is fixed to the furnace mouth; When the diffusion boat is outside the heat treatment furnace, the lid is positioned close to the diffusion boat and moves together with the diffusion boat.

Effect: With this configuration, the opening of the quartz tub or quartz tube is cooled immediately after it is put into the quartz duplex in the diffusion boat or the furnace main body, thereby preventing heat radiation from the heat treatment furnace opening and preventing air from flowing into the quartz tube. The entrainment of the oxide film is also minimized, and the uniformity of the film thickness and the properties of the oxide film can be easily improved.

Embodiment FIG. 1 is a block diagram of a heat treatment apparatus according to an embodiment of the present invention.
FIG. 4 is a side sectional view showing each state during and after charging. In FIG. 1(A), the quartz cap 15 is
It had a hole through which the cantilever 16 passed, and was fixed to a gap holding shaft 19 made of SUS. The cap holding shaft 19 is fixed to the nononchirehar holding part 18 with a slide bearing, and a loose spring 20 is attached behind it. In the free state, the strength of the spring and the length of the cap holding shaft were adjusted so that the quartz gap was closest to the diffusion bow I.14. With this configuration, the cantilever holding part 18 is moved and the diffusion boat 14 is put into the quartz tube 12 (B
). At this time, the quartz cap 15 completely closes the furnace mouth. After that, the diffusion boat 14 is further inserted to the center of the quartz tube 15, as shown in FIG. 3(C).

While the diffusion boat 14 is moving, the spring 20 is extended while the quartz cap 15 remains blocking the furnace opening. Quartz cap 15
is held in a stable manner by a ring between the cantilever 16 and the cantilever holding portion 18. In addition, when taking out the diffusion boat 14, the process is reversed until the diffusion boat comes out to the furnace mouth.
Needless to say, the quartz cap keeps the furnace mouth cold and fixed.

In this embodiment, the spring 20 was attached to the rear of the cantilever holding part, but the cantilever holding part 18 and the quartz cap 1
A similar effect can be expected even if a spring is installed between 5 and 5.

Various types of springs can also be used depending on requirements.

Furthermore, it goes without saying that the cantilever holding portion 18 can be controlled by a control means equipped with a mechanical component or an electronic component.

Effects of the Invention As described above, the present invention prevents heat radiation from the furnace mouth of the heat treatment equipment, minimizes the entrainment of air into the quartz tube, and improves the uniformity of the film thickness. A great effect of improving characteristics can be obtained.

[Brief Description of the Drawings] Figures 1 (A) to (C) are side sectional views showing a heat treatment apparatus according to an embodiment of the present invention in various states of its operation process;
The figure is a side sectional view of a conventional heat treatment apparatus. 11...Heater, 12...Quartz tube, 13...Semiconductor substrate, 14...
Diffusion boat, 15... Quartz gap, 16...
...Nononjireba, 17...Rail, 1
8... Cantilever holding part, 19... Cap holding shaft, 20... Spring.

Claims (1)

[Claims] A furnace lid installed at the furnace mouth of the heat treatment furnace is fixed to the furnace mouth when the diffusion boat having a holding shaft is moved inside the heat treatment furnace, and when the diffusion boat is outside the heat treatment furnace, the furnace lid is fixed to the furnace mouth. A heat treatment device characterized in that the heat treatment device is coupled to a mechanism that moves with the diffusion boat in the vicinity of the diffusion boat.