KR-102960634-B1 - Dilution of flammable gases

KR102960634B1KR 102960634 B1KR102960634 B1KR 102960634B1KR-102960634-B1

Abstract

A combustible gas diluent (5) for diluting the flow of combustible gas to a concentration below the combustibility limit of the combustible gas is disclosed. The diluent (5) includes a dilution vessel (10) comprising an outer envelope that defines a longitudinal flow path from an inlet (11) to an outlet (12), at least one air inlet (16) for directing the airflow to the inlet of the diluent, and a combustible gas inlet device (15). The dilution vessel is provided with a plurality of gas flow directional forming elements (30, 32, 34, 36) arranged between the combustible gas inlet device and the outlet and each located at different positions along the length of the dilution vessel. At least one of the plurality of gas flow forming elements is an inwardly oriented gas flow forming element for directing the gas flow away from the outer envelope, and at least one of the gas flow forming elements is an outwardly oriented gas flow forming element for directing the gas flow toward the outer envelope.

Inventors

그린우드 조앤 레이첼
레커트 한스
나이트 게리
갤트리 마이클

Assignees

에드워즈 리미티드

Dates

Publication Date: 20260507
Application Date: 20210407
Priority Date: 20200416

Claims (15)

In a flammable gas diluent for diluting the flow of flammable gas to a concentration below the flammability limit of the flammable gas, A dilution vessel comprising an outer envelope defining a longitudinal flow path from an inlet to an outlet, and At least one air inlet assembly for directing airflow into the inlet of the dilution container, and A combustible gas inlet device comprising a plurality of openings, wherein at least some of the plurality of openings are arranged at different distances toward an inlet end of the dilution container across the cross-section of the dilution container from the outer envelope of the dilution container, and It includes a plurality of gas flow-directing forming elements arranged between the combustible gas inlet device and the outlet, each located at different positions along the length of the dilution vessel, At least one of the plurality of gas flow forming elements is an inwardly oriented gas flow forming element for directing the gas flow away from the outer envelope, and at least one of the gas flow forming elements is an outwardly oriented gas flow forming element for directing the gas flow toward the outer envelope. The above dilution container includes a contraction portion, and the combustible gas inlet device is positioned within the contraction portion so as to accelerate the air before it passes through the combustible gas inlet device. Flammable gas diluent.
In Article 1, It includes at least one gas flow generator for pumping airflow into the air inlet assembly, wherein the at least one gas flow generator is located upstream of the combustible gas inlet device. Flammable gas diluent.
In Article 2, Includes two gas flow generators configured to operate as operating and backup gas flow generators. Flammable gas diluent.
In Article 2 or Article 3, The above at least one gas flow generator and dilution vessel are configured such that the velocity of the airflow in the combustible gas inlet device is greater than the flame velocity of the combustible gas. Flammable gas diluent.
In any one of paragraphs 1 to 3, The above-mentioned combustible gas inlet device is configured such that the opening is directed away from the outlet. Flammable gas diluent.
In Article 5, The opening of the above-mentioned combustible gas inlet device has a diameter of 2 mm to 5 mm. Flammable gas diluent.
In any one of paragraphs 1 to 3, The combustible gas inlet device comprises an outer ring channel and a radial channel extending from the outer ring channel toward the center of the outer ring channel, and the radial channel comprises the opening. Flammable gas diluent.
In any one of paragraphs 1 to 3, The above flammable gas contains hydrogen. Flammable gas diluent.
In any one of paragraphs 1 to 3, The above dilution vessel, flammable gas inlet device, and gas-directing formation are formed of metal and grounded. Flammable gas diluent.
In any one of paragraphs 1 to 3, The inwardly oriented gas flow forming member includes a ring-shaped baffle protruding from the outer envelope, and the outwardly oriented gas flow forming member includes a cone-shaped baffle located in the center, wherein the apex of the cone-shaped baffle faces the inlet of the dilution container. Flammable gas diluent.
In any one of paragraphs 1 to 3, The above dilution container has a volume of less than 70 liters, and the flammable gas diluent is configured to dilute a flow of flammable gas of up to 1,000 SLM. Flammable gas diluent.
In any one of paragraphs 1 to 3, The combustible gas diluent comprises a combustible gas sampler adjacent to the outlet, wherein the combustible gas sampler is in fluid communication with a combustible gas sensor, and the combustible gas diluent further comprises a control circuit for suppressing the flow of combustible gas to the diluent in response to the combustible gas sensor indicating a combustible gas concentration exceeding a predetermined level. Flammable gas diluent.
In a vacuum pumping system for exhausting at least one vacuum chamber within a semiconductor processing tool, A plurality of vacuum pumps for exhausting at least one vacuum chamber, and It includes a reduction system for receiving exhaust gas from at least one of the above-mentioned at least one vacuum chamber, and The above reduction system comprises a flammable gas diluent described in any one of claims 1 to 3. Vacuum pumping system.
In Article 13, The above semiconductor processing tool includes an extreme ultraviolet lithography tool, and the above flammable gas includes hydrogen. Vacuum pumping system.
In Article 13, A housing for accommodating the above plurality of pumps, and The vacuum system further includes an airflow generator configured to allow airflow to flow through the housing to an airflow duct, and The above airflow duct is in fluid communication with the at least one air inlet assembly to supply the air to the combustible gas diluent. Vacuum pumping system.

Description

Dilution of flammable gases The field of the present invention relates to the dilution of flammable gases, and in some embodiments, to vacuum pumping and reduction systems. There are semiconductor manufacturing processes where the gases to be exhausted and reduced are flammable gases such as hydrogen. For example, in lithography, products are manufactured by controlled exposure to a radiation source. In this case, the radiation source is extreme ultraviolet (EUV) radiation. In this process, hydrogen is used in increasingly larger quantities as a curtain gas to shield optics and mirrors from sputtered tin that is excited by a laser and radiates EUV light from the lithography tool. This process is performed in a vacuum, and the vacuum system provides the vacuum pressure required for the process to occur and transports the hydrogen away to safely remove it. In many reduction systems, combustible gases removed from the vacuum process chamber are burned to eliminate the gas. There are associated environmental impacts, and generally, two reduction tools—an operational tool and a backup tool—are required in the event that the burner of the operational reduction tool is switched off. This arrangement is costly in terms of both fuel and space. It would be desirable to provide an alternative method to reduce flammable gases from the gas stream so that the gas stream can be safely discharged. A first aspect provides a combustible gas diluent for diluting a flow of combustible gas to a concentration below the combustibility limit of said combustible gas, wherein the diluent comprises a dilution vessel including an outer envelope defining a longitudinal flow path from an inlet to an outlet, at least one air inlet assembly for directing an airflow into the inlet of said dilution vessel, and a combustible gas inlet device comprising a plurality of openings, wherein at least some of the plurality of openings are arranged at different distances from the outer envelope of said dilution vessel toward the end of said inlet of said dilution vessel across the cross-section of said dilution vessel, and the combustible gas inlet device comprises a plurality of gas flow directional forming members arranged between said combustible gas inlet device and said outlet and each having different positions along the length of said dilution vessel, wherein at least one of the plurality of gas flow forming members is an inwardly oriented gas flow forming member for directing the gas flow away from said outer envelope, and at least one of the gas flow forming members is an outwardly oriented gas flow forming member for directing the gas flow toward said outer envelope. It is a gas flow formation. Flammable gases are difficult to handle and dispose of. For this reason, flammable gases generated by systems are typically treated by burning them in burners, sometimes using methane as fuel. This impacts the environment, is relatively expensive in terms of fuel and space, and may present reliability issues. Despite the problems associated with handling flammable gases, a significant amount can be released into the atmosphere if it can be safely diluted below the flammability limit. Previously, when flammable gases were diluted, they were generally diluted with nitrogen, an inert gas. However, in systems with large volumes of flammable gas, the amount of nitrogen required to reduce the concentration of the flammable gas below the flammability level is, in many cases, extremely expensive. Dilution of flammable gases would be seen as an acceptable alternative to burning flammable gases as a means of reduction, provided it can be done safely. The inventors of the present invention recognized that many of the risks associated with handling flammable gases are related to transporting the flammable gas from the point of use to a point where the flammable gas can be safely mitigated. Therefore, many problems can be solved by providing a diluent that is simple in design, relatively compact, and has almost no moving parts, so that it is used as a point of use diluent to dilute the flammable gas at or near the point where the flammable gas is used. Another advantage of the diluent according to one aspect of the present invention is that, due to its simple design and lack of moving parts, the diluent is robust, reliable, and non-failure-prone. This can be very important in systems where a failure of the reduction unit could cause flammable gas to be blocked from entering the system, which would require the system to stop immediately and potentially damage the system. The above dilution container includes a constriction section, and the combustible gas inlet device is positioned within the constriction section so that the air is accelerated before passing through the combustible gas inlet. When a flammable gas enters a diluent, it may initially be higher than the upper flammability limit, but as it is diluted, it becomes flammable until it is diluted below the