JPH0658890B2 - Chemical reactor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a chemical reaction apparatus that chemically reacts in a reaction furnace to form a thin film on a substrate.

[Conventional technology]

FIG. 4 shows, for example, “Kurokawa, J. et al., Present state and technical problems of low pressure CVD apparatus, p. 113, No. 3, vol. 28, vacuum (198
5) ”is a systematic diagram showing the basic configuration of the low pressure CVD apparatus. In the figure, (1) is a reaction gas supply system such as SiCl ₄ , (2) is a gas valve, and (3) is a hydrolyzable material. A reaction furnace that forms a thin film on a substrate (not shown) by reaction with a reaction gas, (4) is a dust trap attached to the exhaust path (8), and (5) is a reactor attached to the exhaust path (8) An exhaust control valve for adjusting the exhaust amount of the reaction gas in (3), (6) a mechanical booster pump for exhausting the gas in the reaction furnace (3),
(7) is a rotary pump as a suction pump connected in series to the mechanical booster pump (6).

Next, the operation of the above configuration will be described. The gas supply system (1) is a device that mixes a reaction gas and a carrier gas that plays a role of transporting the reaction gas, controls the mixing ratio and flow rate of each gas, and supplies the gas into the reaction furnace (3). By opening and closing the gas valve (2), supply and stop of gas into the reaction furnace (3) are performed. Although not shown, a substrate for forming a thin film is housed in the reaction furnace (3), and a heat source for heating and raising the substrate to a predetermined temperature is provided.

In the reaction operation, the rotary pump (7) and the mechanical booster pump (6) are activated in this order to temporarily exhaust the air in the reaction furnace (3) to a vacuum. afterwards,
After heating the substrate to a prescribed temperature and raising it, the gas valve
When (2) is opened and the reaction gas and the carrier gas are supplied into the reaction furnace (3), the reaction gas chemically reacts on the substrate to form a thin film. At this time, mechanical booster pump (6)
The rotary pump (7) is put into an operating state, and the gas flow resistance is adjusted by changing the opening degree by the exhaust control valve (5), so that the reactor (3 ) Is controlled. For the thin film formation on the substrate, the variations in the film thickness and the thickness are determined by the three factors of the substrate temperature, the gas supply amount, and the pressure in the reaction furnace (3), so each adjustment is very important and precise. Control is needed.

[Problems to be solved by the invention]

In the conventional chemical reaction device configured as described above, decomposition gas of the hydrolyzable reaction gas and unreacted gas are generated along with the chemical reaction in the reaction furnace (3), The gas is sucked into the pumps (6) and (7), and mixed with the lubricating oil to generate solid products such as SiO ₂ and the suction ability is due to biting into the pumps (6) and (7). Not only lowering the pump, but also damaging the pumps (6), (7).

Therefore, assuming a case where this type of product is generated, a dust trap (4) containing an ultrafine filter is provided in the exhaust path (8) from the reactor (3) to the pumps (6) and (7). At the same time, an oil filter (not shown) is provided due to excess circulating oil.

However, since air is taken into the reaction furnace (3) when the reaction furnace (3) is opened for loading and unloading the substrate, if air is sucked in by the pumps (6) and (7), the exhaust gas is exhausted. The decomposed gas or unreacted gas remaining in the path (8) and the dust trap (4) chemically reacts with moisture in the air to produce a large amount of solid products such as SiO ₂ and the dust trap (4) filter is generated. There is a problem that the suction capacity of the pumps (6) and (7) is rapidly reduced due to clogging, and the filter of the dust trap (4) must be replaced each time, and the operating efficiency is extremely poor. It was

The present invention has been made in order to solve the above problems, and to obtain a chemical reaction device that can be used for a long time without reducing the capacity of the suction pump, and the frequency of maintenance such as cleaning is significantly reduced. With the goal.

[Means for solving problems]

The chemical reaction device according to the present invention is one in which a bypass exhaust passage serving as an air passage in the reaction furnace is branched from an exhaust passage between the reaction furnace and the dust trap.

[Work]

In the chemical reaction device of the present invention, the air taken into the reaction furnace when the reaction furnace is opened for loading and unloading the substrate is discharged to the outside via the bypass exhaust path, and the moisture in the air is removed. Generation of a solid product by a chemical reaction with a reaction gas, a decomposition gas, etc. is suppressed.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram showing an embodiment of the present invention, and the same or corresponding portions as those in FIG. 3 are designated by the same reference numerals and the description thereof will be omitted.

In the figure, (11) is a bypass exhaust path whose tip is connected to the exhaust path (8) between the reactor (3) and the dust trap (4) and serves as an air passage in the reactor (3), ) Is an exhaust valve attached to the bypass exhaust path (11), and (13) is a rotary pump as a suction pump attached to the downstream side of the bypass exhaust path (11).

Next, the operation of the above configuration will be described. After mounting the substrate for forming a thin film in the reaction furnace (3), the inside of the reaction furnace (3) is sealed. In this case, the gas valve (2) and the exhaust valves (10) and (12) are closed. In the initial exhaust after mounting the substrate, the air is taken in the reaction furnace (3), so the exhaust valve (12) is opened and the rotary pump (13) is started to activate the inside of the reaction furnace (3). The air is evacuated. When the inside of the reaction furnace (3) reaches a predetermined vacuum pressure, the rotary pump (13) is stopped and at the same time the exhaust valve (12) is closed, and then the gas valve (2) is opened to supply N ₂ or N ₂ from the gas supply system (1). By supplying an inert gas such as Ar, the inside of the reaction furnace (3) is once returned to the atmospheric pressure state.

After returning to atmospheric pressure, the gas valve (2) is closed, the exhaust valve (10) is opened, the rotary pump (7) is started, and the pressure inside the reaction furnace (3) is reduced to a certain pressure, and then a mechanical booster. The pump (6) is activated to further reduce the pressure. When the inside of the reaction furnace (3) reaches a predetermined vacuum pressure, power is applied to the heat source in the reaction furnace (3) to heat and heat the substrate in the reaction furnace (3) to keep it at a constant temperature. Then, the gas valve (2) is opened, and the reaction gas and the carrier gas are supplied into the reaction furnace (3). In order to control the pressure in the reaction furnace (3) to an arbitrary pressure while the reaction gas is being supplied,
Reactor (3) whose opening is changed by the exhaust control valve (5)
The inside is controlled by the target pressure level.

When the reaction operation is completed, the power of the heat source is turned off, the gas valve (2) is closed and the pressure in the reaction furnace (3) is reduced to a lower level, and then the mechanical booster pump (6) and the rotary pump (7) are stopped, Close the exhaust valve (10).

The substrate is taken out by supplying air or an inert gas to the atmospheric pressure inside the reaction furnace (3) and then opening the reaction furnace (3), but until the substrate cools to room temperature It is said that it is desirable to keep it in an inert gas state in terms of quality. It should be noted that it is better to operate the rotary pump (7) in the exhaust path (8) in consideration of the residual reaction gas before replacement with air.

At the time of restarting after the replacement of the substrate, by repeating the same operation as above, the exhaust path (8) does not allow air to flow in by venting only unreacted gas, carrier gas and inert gas. Generation of a solid product due to a reaction between moisture in the air and an unreacted gas or the like is prevented, and the operating periods of the mechanical booster pump (6) and the rotary pump (7) can be significantly improved. Also a rotary pump
Since there is no mixing of moisture in the air into the lubricating oil of (7), it is only necessary to take measures against the reactive gas in the lubricating oil.

In the above embodiment, the mechanical booster pump (6) and the rotary pump (7) were operated in series as a pump.However, if the rotary pump has a sufficient capacity, the mechanical booster pump may be deleted to change its effect. Needless to say

In the above embodiment, the rotary pumps (7) and (13) are installed in the exhaust passage (8) and the bypass exhaust passage (11), respectively. If a filter is installed, even if it is operated by one rotary pump (7) as shown in Fig. 2, as long as the exhaust path is divided into one for reaction gas and one for air, there is a big difference in effect. Absent. In this case, the exhaust valve for path switching is not limited to the exhaust valves (10) and (12) at the branch part,
(8), exhaust valves (14) and (15) are provided on the downstream side of the bypass exhaust passages (11) to prevent the reaction gas or air from flowing into each other. Must be closed.

Further, the moisture remover (16) shown in FIG. 3 may be attached to the bypass exhaust passage (11) on the downstream side of the exhaust valve (12). This moisture remover (16) has a casing (18) partially having a transparent plate (17), and a moisture remover (19) made of synthetic zeolite that absorbs moisture and a moisture absorption indicator made of silica gel impregnated with cobalt chloride. (20) and are mixed and stored. In this case, the change in the color of the moisture absorption indicator (20) can be observed from the transparent plate (17), and the moisture removing agent (19) can be appropriately replaced depending on the degree of change in the color.

〔The invention's effect〕

As described above, in the chemical reaction device of the present invention, the bypass exhaust passage through which the air in the reaction furnace passes is branched from the exhaust passage between the reaction furnace and the dust trap. The production of a solid product due to a chemical reaction with is suppressed, and there is an effect that the suction pump can be used for a long time without deteriorating its performance and the frequency of maintenance such as cleaning is significantly reduced.

[Brief description of drawings]

FIG. 1 is a system diagram of a chemical reaction device according to an embodiment of the present invention, and FIG. 2 is a system diagram of a chemical reaction device according to another embodiment.
FIG. 3 is a partially cutaway sectional view of a moisture remover according to still another embodiment, and FIG. 4 is a system diagram showing an example of a conventional chemical reaction apparatus. In the figure, (3) is the reactor, (4) is the dust trap, and (6)
Is a mechanical booster pump, and (7) and (13) are rotary pumps. In each figure, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yaichiro Takeda 8-1-1 Tsukaguchi Honcho, Amagasaki City, Hyogo Prefecture, Ryoden Engineering Co., Ltd. Itami Works (56) Reference JP-A-60-16802 (JP, A) Actual development Sho 56-141737 (JP, U)

Claims (3)

[Claims] 1. A reaction furnace in which a thin film is formed on a substrate by a chemical reaction with a reaction gas, and a dust trap which is attached to an exhaust path of the reaction furnace and removes powder products and the like generated in the reaction furnace. A suction pump attached to the exhaust passage downstream of the dust trap; and a bypass exhaust passage whose tip is connected to the exhaust passage between the reaction furnace and the dust trap and serves as an air passage in the reaction furnace. A chemical reaction device characterized in that 2. A moisture remover for removing moisture in the air is attached to the bypass exhaust passage.
A chemical reaction device according to the item. 3. The water removing device according to claim 2, wherein the casing having a transparent portion is prepared by mixing and storing synthetic zeolite and an adsorption indicator for instructing the water adsorption state of the synthetic zeolite. Chemical reactor.