JPH0628690B2 - Dry type treatment equipment for hydride waste gas - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus for treating a hydride-based waste gas such as silane from a semiconductor manufacturing process.

<Prior art> Since hydride-based waste gas is poisonous or has a strong ignition property, it is released after being detoxified in the processing tower. , Silicon, silicon dioxide, silicon monoxide, etc. are mixed, and if these particles directly enter the processing tower, the processing capacity in the processing tower will be affected due to increased pressure loss, blockage, etc. Sex also increases.

Therefore, conventionally, by disposing a pretreatment tank storing an alkaline aqueous solution such as a sodium hydroxide aqueous solution in the waste gas supply path for supplying the waste gas to the treatment tower, and bubbling the waste gas in the sodium hydroxide aqueous solution, The fine particles were removed from the waste gas, and the waste gas containing no fine particles was fed into the processing tower.

<Problems to be solved> However, when bubbling waste gas from the semiconductor manufacturing process in an aqueous sodium hydroxide solution, the waste gas discharged from the pretreatment tank is excessively humidified, and When the gas flows into the processing tower, the surface of the processing agent filled in the processing tower will be coated with water glass produced by the reaction of silane and the alkaline aqueous solution, and the life of the processing agent will be shortened. There was a problem such as clogging due to the adhesion of the treatment agent.

Also, pull the waste gas from the waste gas source with a vacuum pump,
In this case, it was sent to the pretreatment tank.In this case, immediately after the vacuum pump was stopped, the negative pressure of the pump body and semiconductor manufacturing equipment sucked back the sodium hydroxide aqueous solution stored in the pretreatment tank, The main body and the semiconductor manufacturing device may be contaminated or damaged.

The present invention has been made by paying attention to such a point, and it is possible to perform the pretreatment without humidifying the waste gas while removing the fine particles from the waste gas, and moreover, it is stored in the pretreatment tank immediately after the vacuum pump is stopped. It is an object of the present invention to provide a processing device that does not suck back the processing liquid that is present.

<< Means for Solving the Problem >> In order to achieve the above object, the present invention provides a pretreatment tank arranged in a waste gas supply path for supplying a waste gas to a treatment tower with a hardly volatile inorganic acid liquid such as sulfuric acid in a pretreatment tank, A volatile organic acid liquid or a dust-removing liquid consisting of a hardly volatile oil is stored, and the waste gas is bubbled in the hardly volatile liquid to remove fine particles contained in the waste gas. A backflow liquid storage tank is formed between the vacuum pump and the pretreatment tank, and a check valve is disposed in a gas passage that connects the backflow liquid storage tank and the pretreatment tank.

<< Operation >> In the present invention, the hardly volatile acid liquid or the less volatile oil is stored in the pretreatment tank arranged in the waste gas supply path for supplying the waste gas to the treatment tower, and the waste gas is stored in the hardly volatile liquid. By bubbling, it is configured to remove the fine particles contained in the waste gas, so the fine particles contained in the waste gas are removed in the hardly volatile liquid, and moreover, from the pretreatment tank. The discharged waste gas will not be excessively humidified.

In addition, since a backflow liquid storage tank is formed between the vacuum pump and the pretreatment tank, and a check valve is arranged in the gas passage that connects the gas storage tank and the pretreatment tank, the vacuum pump Even if the negative pressure in the pump body and semiconductor manufacturing equipment acts on the gas passage immediately after the stop, the check valve is placed in the passage between the backflow liquid storage tank and the pretreatment tank. It is possible to prevent the dust removing liquid stored in the gas from flowing backward through the gas passage. Furthermore, even if the dust removal liquid leaks from the check valve when the vacuum pump is stopped, the leaked dust removal liquid is trapped in the backflow reservoir, and the dust removal liquid flows back to the pump body and the semiconductor manufacturing equipment. Will disappear.

<< Example >> A drawing is a flow chart showing a processing system of hydride system waste gas.

Reference numeral (1) in the figure is a hydride-based waste gas generation source for semiconductor manufacturing equipment, etc. This hydride-based waste gas generation source (1) communicates with a processing tower (3) through a waste gas discharge passage (2). ing. The treatment tower (3) is filled with a treatment agent (4) obtained by impregnating a solid carrier such as alumina with sodium hydroxide and potassium permanganate.

The waste gas discharge path (2) between the hydride-based waste gas generation source (1) and the processing tower (3) has a vacuum pump from the waste gas generation source (1) side.
(5), the backflow liquid storage tank (6) and the pretreatment tank (7) are arranged in this order. Further, the waste gas discharge path (2) between the backflow liquid storage tank (6) and the pretreatment tank (7) is connected to the pretreatment tank from the backflow liquid storage tank (6) side.
A check valve (8) is arranged to allow waste gas flow to (7).
The pretreatment tank (7) stores a dust removing liquid (9) consisting of a hardly volatile strong acid liquid represented by concentrated sulfuric acid and phosphoric acid, and the waste gas is blown into the dust removing liquid (9). Bubbling. Then, since the fine particles such as silicon, silicon dioxide, and silicon monoxide contained in the waste gas during the bubbling are removed by the dust removing liquid (9), the fine particles flow into the treatment tower (3). In addition, since the non-volatile strong acid is used for the dust removal liquid (9), the dust removal liquid component does not flow into the treatment tower (3), and the treatment agent (4) in the treatment tower (3) Does not affect. Moreover, since the hardly volatile strong acid solution has a large dehydrating action, the waste gas flowing into the treatment tower (3) is in a dry state, and water glass is not generated on the surface of the treatment agent (4).

In the above embodiment, the dust removal liquid stored in the pretreatment tank (7)
Although (9) is formed of a hardly volatile acid liquid, the dust removing liquid (9) may be made of a hardly volatile oil such as a vacuum pump lubricating oil (for example, fumbling).

<< Effect >> In the present invention, the hardly volatile acid liquid or the less volatile oil is stored in the pretreatment tank arranged in the waste gas supply path for supplying the waste gas to the treatment tower, and the waste gas is stored in the hardly volatile liquid. By bubbling, it is configured to remove the fine particles contained in the waste gas, so the fine particles contained in the waste gas are removed in the hardly volatile liquid, and moreover, from the pretreatment tank. The discharged waste gas will not be excessively humidified,
Since the surface of the treatment agent is not coated with water glass produced by the reaction of silane and alkali in the treatment tower, the performance of the treatment agent can be sufficiently exhibited.

In addition, a backflow liquid storage tank is formed between the vacuum pump and the pretreatment tank, and a check valve is arranged in the gas passage that connects the backflow liquid storage tank and the pretreatment tank. Even if the negative pressure in the pump body and the semiconductor manufacturing equipment acts on the gas passage immediately after the stop, the check valve is placed in the passage between the reverse reservoir tank and the pretreatment tank. It is possible to prevent the dust removal liquid stored in the processing tank from flowing backward through the gas passage. Further, even if the dust removal liquid leaks from the check valve when the vacuum pump is stopped, the leaked dust removal device is trapped in the backflow liquid storage tank, and the dust removal liquid flows back to the pump body and the semiconductor manufacturing equipment. You can get rid of things.

[Brief description of drawings]

 The drawing is a flow chart showing a treatment system for hydride-based waste gas. 1 ... Waste gas generation source, 2 ... Waste gas discharge passage, 3 ... Waste gas processing tower, 5 ... Vacuum pump, 6 ... Backflow liquid storage tank, 7 ... Pretreatment tank, 8 ... Check Valve, 9 ... Dust removal liquid.

Claims (2)

[Claims] 1. A vacuum pump (5) and a backflow liquid storage tank (6) are provided in a waste gas discharge passage (2) that connects a hydride-based waste gas generation source (1) such as silane and a waste gas treatment tower (3). ), The pretreatment tank (7) is arranged in order, and the waste gas is stored in the pretreatment tank (7) as a dust removing liquid (9) by storing the hardly volatile inorganic or organic acid liquid in the hardly volatile inorganic or organic acid liquid. It is configured to remove fine particles contained in the waste gas by bubbling with a backflow liquid storage tank.
A hydride-based waste gas characterized in that a check valve (8) that allows gas to flow in the forward flow direction is arranged in a waste gas discharge passage (2) that connects the (6) and the pretreatment tank (7). Dry processing device 2. A vacuum pump (5) and a backflow liquid storage tank (6) in a waste gas discharge passage (2) which connects a waste gas treatment source (3) with a hydride waste gas generation source (1) such as silane. ), The pretreatment tank (7) is arranged in order, and the non-volatile oil is stored in the pre-treatment tank (7) as the dust removing liquid (9) and the waste gas is bubbled in the non-volatile oil to remove the waste gas. It is configured to remove the fine particles contained therein, and the waste gas discharge passage (2) that connects the backflow liquid storage tank (6) and the pretreatment tank (7) to the reverse flow direction that allows gas to flow in the forward direction. Stop valve
Dry treatment device for hydride-based waste gas, characterized in that (8) is arranged