JPH04350927A - Heat treatment device for semiconductor wafer - Google Patents

Abstract

PURPOSE:To provide a heat treatment device for a semiconductor wafer, which can form high quality of diffusion layer and oxide layer practically without being influenced by the air penetrating into a rector from outside. CONSTITUTION:To the horizontal reaction furnace 1 intended for a heat oxidation furnace and a heat diffusion furnace used in the process stage of a semiconductor wafer 6 gas supply nozzles 9 connected with a process gas supply pipe 8 are arranged in the circumferential area of the center inside the furnace, and gas exhaust ports 5 are provided at both ends in front and in rear of the reactor, and process gas is blown and supplied from the circumferential area of the center inside the furnace to the semiconductor wafer through the gas ejection ports 10 of the gas supply nozzles.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus for semiconductor wafers, which is applicable to thermal oxidation furnaces and thermal diffusion furnaces used in processes for attaching oxide films to semiconductor wafers and diffusing impurities.

0002

[Prior Art] In the semiconductor wafer processing step mentioned above, a semiconductor wafer is loaded onto a boat and carried into a reactor heated by a heater, and in this state, process gas (oxygen, doping gas, carrier wafer processing such as thermal oxidation and thermal diffusion.

FIG. 4 shows a conventional heat treatment apparatus. In the figure, 1 is a horizontal reactor made of quartz glass, etc., and 2 is a boat entrance/exit opened at one end of the reactor 1. 3 is an opening/closing door provided, 4 is a process gas supply port opened at the rear end of the reactor 1 (the end opposite to the entrance/exit 3), and 5 is a gas exhaust port opened near the boat entrance/exit 3 of the reactor 1. . Note that a heater (not shown) is provided on the outer peripheral side of the reactor 1. Here, semiconductor wafer 6
are mounted on a boat 7 in an upright position, and carried into the center of the reactor 1 by operating a boat loader (not shown), and in this state, process gas is supplied into the reactor from the gas supply port 4. Processes such as thermal oxidation and thermal diffusion are performed.

0004

[Problems to be Solved by the Invention] In the reactor configured as described above, the door 2 is opened when the semiconductor wafers 6 are loaded onto the boat 7 and carried into the reactor, so that air is removed from the surrounding atmosphere side. enters and spreads into the furnace. In addition,
By closing the door 2 after loading the wafer and supplying process gas into the furnace from the rear end, this intruding air is replaced with the process gas, pushed to the entrance and exit side, and exhausted from the exhaust port 5 to the exhaust processing equipment. Ru.

By the way, when air that has entered the furnace from the outside touches a semiconductor wafer that has been heated to a high temperature before being exhausted, the surface of the semiconductor wafer undergoes a thermal oxidation reaction. However, since the air that enters from the atmosphere contains components other than oxygen, the oxide film that grows on the semiconductor wafer due to this intruding air is affected by the subsequent diffusion by regular process gases and the diffusion formed by oxidation treatment. layer, deteriorate the quality of the oxide film. In addition, in heat treatment equipment that processes wafers at normal pressure, there is a phenomenon called air bag diffusion in which air enters the reactor from the outside through a small gap between the reactor and the door even when the door 2 of the reactor 1 is closed. , This may cause problems that adversely affect wafer processing.

The present invention has been made in consideration of the above points, and is aimed at the above-described horizontal reactor heat treatment apparatus, and by changing the supply point of process gas to the reactor, air intrusion into the reactor can be reduced. An object of the present invention is to provide a semiconductor wafer heat treatment apparatus that can form a high quality diffusion layer and oxide film while avoiding adverse effects on wafer processing.

[0007]

[Means for Solving the Problems] In order to solve the above problems, in the heat treatment apparatus of the present invention, process gas is directed from the peripheral area of the central part of the furnace toward the semiconductor wafer in accordance with the position of the boat being carried into the furnace. It shall be constructed so that it can be blown out.

In order to uniformly flow the process gas to the semiconductor wafers carried into the reactor, the gas supply nozzle connected to the process gas supply pipe should be directed toward the semiconductor wafers carried into the reactor. It is reasonable to arrange the exhaust ports on the circumference of the reactor at the center of the reactor, and in order to quickly exhaust the air that has entered the reactor from the outside by introducing the process gas, the process gas exhaust ports are placed at both the front and rear ends of the reactor. It is better to set it in

[0009]

[Operation] With the above structure, process gas is directly blown and supplied from the peripheral area of the central part of the reactor toward the semiconductor wafers carried into the central position of the reactor together with the boat. Therefore, the air that entered the furnace when the door was opened when loading the semiconductor wafers is quickly removed from the center of the furnace toward the edges when the process gas supply starts, and the atmosphere around the wafers is replaced with the process gas. It becomes like this. As a result, the opportunity for the intruding air to come into contact with the semiconductor wafer in a high-temperature heated state is limited to a very short time, and there is almost no adverse effect on wafer processing. In addition, with air bag diffusion, process gas is directly blown out to the area around the semiconductor wafer, so the intruding air is exhausted before it spreads to the center of the furnace where the semiconductor wafer is located, which has a negative impact on wafer processing. Never. In addition, when the semiconductor wafers are mounted on a boat in an upright position, the process gas is blown out parallel to the semiconductor wafers from the periphery and flows evenly over the wafer surface, which allows the wafer processing reaction to occur. will proceed evenly.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 3 show the structure of an embodiment of the present invention, and the same members corresponding to those in FIG. 4 are given the same reference numerals. That is, in the configuration of the embodiment, the process gas supply pipe 8 is drawn into the inside of the reactor 1 and the gas supply nozzle 9 connected to the gas supply pipe 8 is placed in the central part of the reactor in accordance with the loading position of the semiconductor wafer 6. are located around the area. Further, the exhaust ports 5 are provided at two separate locations at the front and back ends of the reactor 1. On the other hand, regarding the gas supply nozzle 9, FIG.
In this case, a plurality of tubular gas supply nozzles 9 are distributed on the inner peripheral surface of the reactor 1, and each nozzle has a gas outlet 10 opening toward the semiconductor wafers 6 mounted on the boat 7. On the other hand, in the application example shown in FIG.
A large number of gas ejection ports 10 are distributed and open toward.

With this configuration, when a process gas is supplied to the reactor 1 through the gas supply pipe 8, the process gas is directed toward the semiconductor wafer 6 carried into the center of the furnace through the gas outlet 10 of the gas supply nozzle 9. Air is blown out from the surrounding area parallel to the wafer surface. The gas blown into the furnace washes the surface of the semiconductor wafer 6 and then flows in the front and rear directions, and is then exhausted through the exhaust port 5 to an exhaust processing device (not shown). Further, as the process gas is blown out and supplied, air that has entered the furnace from the outside atmosphere side through the boat inlet/outlet 3 is also exhausted from the exhaust port 5 together with the process gas before it spreads to the center of the furnace.

0012

As described above, according to the heat treatment apparatus of the present invention, process gas is blown out from the center of the reactor toward the semiconductor wafer and supplied from the surrounding area to the semiconductor wafer carried into the reactor. As a result, the air that entered the furnace from the outside when semiconductor wafers were brought in can be quickly removed from around the semiconductor wafer located in the center of the furnace as soon as the process gas supply starts, and then exhausted through the exhaust port. can. Additionally, air that has entered during wafer processing due to the air bag diffusion phenomenon is exhausted through the exhaust port together with the process gas before it diffuses to the center of the furnace. In addition, the process gas flows out from the peripheral area of the furnace parallel to the wafer surface and washes away the semiconductor wafers loaded on a boat and carried into the furnace. This makes it possible to uniformly form a high-quality diffusion layer and oxide film on the semiconductor wafer while avoiding the adverse effects of air entering from the outside on wafer processing.

[Brief explanation of drawings]

[Fig. 1] A cross-sectional diagram of a reactor according to an embodiment of the present invention.

[Figure 2
]Front view of Figure 1

[Figure 3] Front view of a reactor showing an applied example of the present invention

[Figure 4] Cross-sectional diagram of the configuration of a conventional reactor

[Explanation of symbols]

1 Reactor 2 Door 3　　　　Boat entrance 5 Exhaust port 6 Semiconductor wafer 7 Boat 8 Process gas supply pipe 9 Gas supply nozzle 10 Gas outlet

Claims (3)

[Claims] Claim 1: A semiconductor wafer heat treatment apparatus intended for thermal oxidation furnaces and thermal diffusion furnaces used in semiconductor wafer processing steps, in which a boat carrying semiconductor wafers is placed in the center of a horizontally arranged reactor. Carry it to the fixed position of
In a device that processes wafers by supplying process gas into the furnace in this state, the process gas is blown out and supplied from the area around the center of the furnace toward the semiconductor wafers in line with the position of the boat being brought into the furnace. A heat treatment apparatus for semiconductor wafers, which is characterized by: 2. The heat treatment apparatus according to claim 1, wherein the gas supply nozzle connected to the process gas supply pipe is arranged on the peripheral surface of the central part of the reactor, facing the semiconductor wafer carried into the reactor. Features of semiconductor wafer heat treatment equipment. 3. The heat treatment apparatus for semiconductor wafers according to claim 1, wherein process gas exhaust ports are provided at both front and rear ends of the reactor.