JPH04210209A - Harm removing device for nitrogen fluoride - Google Patents

Abstract

PURPOSE:To maintain the treatment capacity high in harm removal of NF3 in a range over a long period by arranging oxygen removal tanks packed with a granular deoxidizing agent to the front and rear parts of a silicon packed tank fitted to the flow path of NF3. CONSTITUTION:A treating agent tank 3 packed with granular metallic silicon 2 is arranged to the flow path 1 of NF3. An oxygen removal tanks 4 are arranged respectively to the inlet and outlet parts of gaseous NF3 into this tank 3. The tank 3 is constituted so that the temp. thereof is raised by an external heater 5. A deoxidizing agent 6 is constituted by carrying manganese oxide on a carrier such as activated carbon and iron oxide. This deoxidizing aget 6 is packed in the tanks 4. Since oxygen is removed by the deoxidizing aget 6 in the oxygen removal tanks, oxygen is not infiltrated into the silicon packed tank. Formation of an oxidative film is inhibited on the surface of silicon. Durability of the treating agent is raised and high treatment capacity is maintained in a range over a long period.

Description

[Detailed description of the invention]

[00011

[Industrial Field of Application] The present invention relates to nitrogen fluoride abatement technology. [0002] [Prior Art] Nitrogen fluoride (NF3) has attracted attention as a dry etching agent or fluorinating agent for LSI.
In particular, as a dry etching agent, compared to perfluorocarbon-based etching agents such as CF4, it has the advantage of causing extremely little contamination of the LSI substrate during etching. [0003] On the other hand, NF3 is extremely stable in the atmosphere, only slightly soluble in water, and is a toxic gas of TLVloppm, so when using it, it is necessary to remove the residual gas when exhausting it. [0004] Therefore, conventionally, as a method of abatement of NF3, N
A method has been proposed in which a gas containing F3 is reacted with at least one member selected from silicon, boron, tungsten, molybdenum, vanadium, selenium, tellurium, germanium, and non-oxides of these at high temperatures ( Special Publication No. 63-48570). [0005]

[Problem to be Solved] However, in the conventional method, a processing agent such as silicon is heated to a high temperature of 200 to 800°C to increase its activity and react with NF3. When oxygen enters the filling tank,
There is a problem in that the processing agent reacts with oxygen to form an oxide film on the surface of the processing agent, which restricts the reaction with NF3 and reduces the durability of the processing agent. [00061] The present invention has been made with attention to such points, and an object of the present invention is to provide a harm removal device that can exhibit good harm removal ability over a long period of time. [0007]

[Means for Solving the Problems] In order to achieve the object stated above, the present invention provides a nitrogen fluoride abatement device formed to abate nitrogen fluoride by reacting it with silicon. The device is characterized in that oxygen removal tanks filled with granular oxygen scavenger are placed before and after the silicon-filled tank installed in the flow path. [0008]

[Function] In the present invention, oxygen removal tanks filled with granular oxygen scavenger are placed before and after the silicon-filled tank installed in the flow path of nitrogen fluoride. ) will be removed by the oxygen scavenger in the oxygen removal tank, preventing oxygen from entering the silicon-filled tank and suppressing the formation of an oxide film on the silicon surface. It will be possible. [0009]

[Example] The drawing is a conceptual diagram showing an NF 3 abatement device, in which granular metal silicon (2
), and an oxygen removal tank (4) is placed at each entrance and exit of the NF3 gas into the treatment agent tank (3), and the treatment agent tank (3) is placed outside the treatment agent tank (3). Heater (5
) is configured so that the temperature can be increased. [00101 The oxygen removal tank (4) is filled with an oxygen scavenger (6) composed of manganese oxide supported on a carrier such as activated carbon or iron oxide. (00111 (Experiment example) A processing agent filling tank (3) was formed from a nickel metal pipe with a diameter of 19.8 mm and a length of 0.5 m.
An oxygen removal tank (4) filled with an oxygen scavenger (6) made of activated carbon supported with manganese oxide is arranged before and after 3), and granular metal silicon (2) is placed in the processing agent filling tank (3) .25
Kg, and this treatment agent filling tank (3) is connected to an external heater (5
), then 100% NF3 was heated to 500℃.
．． It was supplied at a rate of 7 liters/min. The composition of the outlet gas was 2 ppm of NF3, with the remainder being N2 and SiF4. [0012] Furthermore, the relationship between the elapsed time and the discharged NF3 concentration was as shown in the following table. [0013]

[Table 1] (0014) (Comparative Example) With the oxygen removal tank (4) removed from the above-mentioned processing equipment, NF was added to the processing agent filling tank (3) under the same conditions as in the above-mentioned Example.
3 was supplied. In this case, the composition of the outlet gas is 8 NF3.
ppm, and the rest was SiF4. The relationship between the elapsed time and the discharged NF3 concentration in this case was as shown in the right column of Table 1. [0015]

Effects of the Invention In the present invention, oxygen removal tanks filled with granular oxygen scavenger are placed before and after the silicon-filled tank installed in the nitrogen fluoride discharge path.
Oxygen that tries to enter the processing agent tank is removed by an oxygen scavenger in the oxygen removal tank, preventing oxygen from entering the silicon filling tank and suppressing the formation of an oxide film on the silicon surface. It is possible to increase the durability of the processing agent and maintain high processing capacity over a long period of time.

[Brief explanation of the drawing]

FIG. 11 is a conceptual diagram showing the abatement device of NF3. [Explanation of symbols] 1...N F 11 flow path, 2...Metal silicon, 3...Treatment agent tank, 4...Oxygen removal tank, 5...External heater, 6... Oxygen absorber.

Claims (1)

[Claims] Claim 1: In a nitrogen fluoride abatement device formed to abate nitrogen fluoride by reacting it with silicon, granular deoxidizers are provided before and after a silicon-filled tank installed in a flow path for nitrogen fluoride. A nitrogen fluoride abatement device characterized by having an oxygen removal tank filled with a nitrogen fluoride agent.