JPS6351918A - Gas purifier for semi-conductor manufacturing device - Google Patents

Abstract

PURPOSE:To grade up purity of gas fed into a reaction chamber by providing, from the flow inlet to the flow outlet side, a first filter, an adsorbent for remov ing impure gas and a high-density second filter for collecting fine particles in a housing. CONSTITUTION:Gas coming from a flow inlet 6 of a housing 2 passes through a plate-shaped first filter 11, and water content and carbon dioxide gas are removed by an adsorbent 9 (for example, zeolite or the like) for removing impure gas, and fine particles such as fine dust, water particles, foreign matters and the like are collected by a following second filter 12. The second filter is constituted of ceramics, metal and the like, and is of high density of around 0.1mu mesh. High-purity gas coming out of the second filter 12 is exhausted out of a flow outlet 7 and transferred to a reaction chamber for semi-conductor manufacturing process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gas purifier for semiconductor manufacturing equipment for sending ultra-high purity gas to a reaction chamber in a semiconductor manufacturing process.

[Conventional technology]

In a high-purity gas line generally used in semiconductor manufacturing equipment, the high-purity gas that has passed through the gas purification V device passes through a gas control system to control the flow rate and pressure before flowing into the reaction chamber. As is well known, the presence of impure gases causes defects in semiconductor devices produced in the reaction chamber, so not only the gas purification equipment but also the gas control system has been significantly purified.

[Problem that the invention seeks to solve]

However, since the gas control system is disposed downstream of the gas equipment, it has been impossible to completely eliminate gas contamination within the gas control system. Despite this, in recent years, with the ultra-precision of semiconductor devices, there has been an increasing demand for ultra-high purity gas sent into the reaction chamber, and conventional high-purity gas lines cannot meet these demands. The current situation is that it is not enough. Adsorbents are usually used to purify gases, but adsorbents have the decisive drawback of generating a large amount of dust in the gas supply system.

[Means for solving problems]

The present invention relates to a gas purifier connected to the gas intake side of a reaction chamber in a semiconductor manufacturing process, which includes a housing having a gas inlet and an outlet, and a gas purifier for removing impurity gas housed within the housing. an adsorbent, a first filter provided within the housing between the inlet and the adsorbent, and a particulate collector provided between the adsorbent and the outlet within the housing. It is characterized by comprising a high-density second filter.

The roughness of the second filter is set to be large enough to sufficiently collect microparticles generated from the adsorbent and the like. For example, zeolite is used as the adsorbent, but it is of course possible to use other adsorbents.

(Function) It is effective to provide the above gas purifier immediately before the reaction chamber on the downstream side of the gas control system. Since this gas purifier has an adsorbent and a filter built into the housing and can be configured compactly, it can be easily added to an existing high-purity gas line immediately before the reaction chamber.

A well-known gas purification device is separately installed upstream of the gas control system to produce desired high-purity gas.

The high-purity gas that passes through the gas control system and is controlled to a predetermined flow rate and pressure is sent to the reaction chamber through the gas purifier of the present invention, which not only makes it possible to further increase the purity of the gas, but also Even if there is contamination within the gas control system, ultra-high purity gas can be supplied to the reaction chamber by passing through this purifier.

The adsorbent can be regenerated by heating the gas purifier to a high temperature and causing the purge gas to flow back from the outlet side to the inlet side.

Since the first filter is placed on the downstream side of the adsorbent through which the purge gas flows, that is, on the inlet side of the housing, minute dust from the adsorbent accompanying the purge gas will flow out to the inlet side and contaminate the piping system, etc. can be prevented.

〔Example〕

The gas purifier 1 shown in FIG. 1 includes a substantially cylindrical metal housing 2. The gas purifier 1 shown in FIG. The housing 2 includes a bottomed housing body 2a that is open at the upper end in the figure, and a housing lid 2b that closes the opening of the housing body 2a.

The housing lid 2b is fixed to the housing body 2a by a screw-in cap 3 having a threaded portion 3a. A metal gasket 4 is provided between the housing body 2a and the housing 12b to maintain airtightness between them.

A gas inlet 6 is provided in the center of the housing lid 2b. Further, a gas outflow lower is provided in the center of the bottom wall portion of the housing body 2a. Gas used in the semiconductor manufacturing process flows from the inlet 6 to the housing 2.
After being introduced into the interior of the housing 2, the gas flows out from the outflow lower part, and the interior of the housing 2 is formed in a shape that prevents the above-mentioned gas from stagnation.

In addition, the metal surface that comes into contact with the gas has a mirror finish with no process-altered layer so that the surface area is as small as possible. Reduces emissions. Incidentally, threaded portions 8a and 8b for connection to a piping system are provided on the outer periphery of the inlet 6 and the outer periphery of the outflow lower, respectively.

The housing 2 houses an adsorbent 9 (only a portion of which is shown) for absorbing impure gas. This adsorbent 9 is, for example, zeolite, which adsorbs water molecules or carbon dioxide gas. The adsorbent 9 mixed with fine powder of nickel (N i ) has the ability to remove oxygen gas. In this case, it is more effective to use the same material as the gold a (for example, Ni) mixed in the adsorbent for the housing 2.

Furthermore, a plate-shaped first filter 11 is provided within the housing 2 between the inlet 6 and the adsorbent 9. The first filter 11 is desirably fine-mesh like the second filter 12 described later, in order to prevent the minute dust generated on the adsorbent 9 from flowing back to the inlet 6 side.
It is also possible to use a coarse filter with a comparison of about 0, such as a so-called metal mesh filter.

On the other hand, a second filter 12 is provided within the housing 2 between the adsorbent 9 and the outflow lower. The second filter 12 is formed into a substantially cylindrical shape with a closed tip so as to have a large filtration area through which gas passes. This second filter 12 is arranged concentrically with the housing 2, and the outer circumferential side of the second filter 12 is filled with adsorbent 9.

The inside of the second filter 12 passes through the outflow lower.

The second filter 12 has a function of collecting fine particles such as fine dust, water particles, and foreign substances generated from the adsorbent 9, and has a sufficiently small mesh roughness of, for example, 0.1 μ. The second filter 12 is made of a material that has high mechanical strength and high temperature during regeneration of the adsorbent 9 (for example, about 350°C).
), for example, sintered metals such as stainless steel and alumina (Aff203) ceramics can be used, but especially conductive ceramics (such as SiC) with corrosion resistance can be used. ) is desirable.

That is, if the filter 12 is electrically insulating, when gas flows through the small pores of the filter 12 at high speed, it may be charged with static electricity of several hundred thousand volts or more. When this static electricity causes a discharge, it not only gasifies surrounding substances and causes the generation of impure gas, but also causes a strong oxidation reaction if oxygen gas is flowing at this time, which may lead to combustion. Therefore, the above-mentioned problem can be solved by forming the filter 12 from a conductive material such as SiC to allow static electricity to escape.

As an example of the gas purifier 1 having the above configuration is shown in FIG. 2, the gas intake side of the reaction chamber 15 is connected to the gas outflow lower via the switching valve mechanism 14. Further, the gas inlet 6 side is connected to a gas control system 18 via a switching valve mechanism 17 . A well-known gas purification device 119 is provided upstream of the gas control system 18 .

Although the switching valve mechanisms 14 and 17 may be provided separately from the housing 2, they are preferably integrated with the housing 2 in order to make the device more compact.

In the device of the above embodiment, the high purity gas purified by the gas purification device 19 is sent to the gas control system 18, where it is controlled to a predetermined flow rate and pressure and sent to the gas purifier 1.

In this case, as shown in FIG.
7a and the other valve 14b.

Valve 17b is kept closed. In the purifier 1, a small amount of impurity gas contained in the high-purity gas is absorbed by the adsorbent 9, and the second filter 12 reliably removes fine particles such as minute dust and foreign matter generated from the adsorbent 9. be captured. The ultra-purified gas is sent to the reaction chamber 15. Therefore, not only can the purity of the gas be further increased, but even if contamination occurs within the gas control system 18, the most pure ultra-high purity gas can be supplied to the reaction v15. Therefore, the quality of film formation or etching in the reaction chamber 15 is improved, reproducibility and reliability are ensured, and the yield is significantly improved. In addition, in order to improve the performance of the adsorbent 9, it is also effective to add an electronic refrigeration means or a cooling means using liquefied gas to the housing 2. Alternatively, a filter with a honeycomb structure may be used.

To regenerate the adsorbent 9, as illustrated in FIG. 3, one valve 14a, 17a is closed, and the other valve 14b,
With the valve 17b opened, the gas fJ making device 1 is heated to a high temperature (for example, 350° C.), and the purge gas is caused to flow back from the outflow lower to the inflow port 6. At this time, since the first filter 11 is disposed downstream of the adsorbent 9 through which the purge gas flows, that is, on the inlet 6 side, fine dust flows from the adsorbent 9 toward the inlet 6 as the purge gas flows. This will be prevented. In order to heat the adsorbent 9, it may be heated from outside the housing 2 using a heater or a furnace, but depending on the case, a heater for regenerative heating may be built into the housing 2. For example, an inert gas such as nitrogen, argon, or helium is used as the purge gas.
When the adsorbent 9 is mixed with Ni fine powder for oxygen removal, activation is performed by flowing hydrogen gas.

In addition, as shown in FIG. 4, a plurality of gas purifiers 1.1
If the gas purification and the regeneration of the adsorbent 9 can be performed simultaneously by connecting them in parallel, the operating efficiency of the system will be improved. That is, the valve 14a connected to one gas vessel 1.

By opening the valve 17a and closing the valves 14b and 17b, the purifier 1 performs [4] of the gas. In addition, in the other purifier 1', the valves 14a' and 17a' are opened and the valves 14b' and 17b' are closed to flow the purge gas from the outflow lower to the inlet 6 side. Then, the adsorbent 9 can be regenerated.

The gas purifier 1 shown in FIG. 5 shows another embodiment of the present invention. In this embodiment, a cylindrical second filter 12 with a small diameter is placed inside a cylindrical first filter 11.
are arranged concentrically.

Then, an adsorbent 9 (only a portion of which is shown) is filled between the filters 11 and 12. Filters 11.12 are for example An203
It is made of ceramic such as or SiC, and its roughness is large enough to collect fine particles generated by the adsorbent 9. The adsorbent 9 may be similar to the embodiments described above. The housing lid 2b is welded to the housing body 2a.

The filters 11, 12 are held between the bottom part of the housing body 2a and the filter holder 21, and the filter holder 21 is held down by a compression coil spring 22. With such a structure, it is possible to absorb the dimensional difference in the axial direction caused by the difference in thermal expansion between the metal, the ceramic, and the adsorbent 9 at high temperatures when the adsorbent 9 is regenerated.

Further, in this embodiment, in order to improve the sealing performance at both ends of the filter 11.12, one end of the filter 11.12, the housing main body 2a, and the filter 41.12 are connected to each other.
The other end portion and the filter holder 21 are structured to fit into each other, and the fitting portions of both sides are mirror-finished. Further, sealing performance may be ensured by interposing a nickel foil or the like in this region. In addition,
In order to prevent dust from being generated when the adsorbent 9 is filled into the housing 2, it is conceivable to harden the outer circumferential surface, inner circumferential surface, both end surfaces, etc. of the adsorbent 9 in advance by means such as sintering.

In addition, the gas purifier 1 is not only installed just before the reaction 15, but also, for example, if there is a pipe with a lower level of cleanliness upstream, this purifier 1 can be connected to the end of the pipe with a lower level of cleanliness to achieve a higher level of cleanliness. If it is connected to piping, it will not pollute the downstream clean piping, making it even more effective.

The filter built-in gas purifier according to the present invention is applied to an RF bias sputtering apparatus, for example, A! The effect of forming the second film will be explained.

In LSIs with finer patterns, a film formation technology is required to fill metal holes in thin and deep through holes with large aspect ratios, so the Ar gas pressure in the sputtering space is low, around 1 x 10" T Orr. The pressure state is usually used.Therefore, the flow rate of Ar gas is several tens of cc/
The sputter target material (
In this case, Affi) oxidizes the surface, lowering the sputtering efficiency and deteriorating the film formation rate. Further, the A.degree. C. film formed on the semiconductor wafer is oxidized, increasing the resistivity and deteriorating the electromigration resistance. In a fine pattern LSI, it is desirable that the wiring resistance be as small as possible and the R current capacity M be as large as possible. Oxidation of the film forming table E due to moisture entering the sputtering space must be minimized as much as possible.

In the RF bias sputtering system in which the filter-equipped gas yI device according to the present invention is installed just before the reaction chamber, Ar
For example, the moisture concentration inside is 10 pl) b (dew point -100
The resistivity of the formed He2 thin film is approximately 2.5×10' ΩU, which is almost equal to the resistivity of bulk aluminum of high purity. Electromigration does not appear at all up to about 1x10s person/ci, and submicron LS
This technology is extremely suitable for forming metal films for wiring. The filter-integrated gas purifier of the present invention is extremely effective not only in metal film formation, but also in processes that require high quality, such as Si epitaxial growth and thin gate oxide film formation.

〔Effect of the invention〕

According to the present invention, the purity of the gas introduced into the reaction chamber can be further increased, and the ultra-high purity gas with the highest purity can be flowed into the reaction chamber, so that the semiconductor manufacturing process in the reaction chamber can be optimized. It can be done under certain conditions.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a gas purifier showing an embodiment of the present invention;
Fig. 2 is a system diagram of a semiconductor manufacturing device using the gas purifier shown in Fig. 1, Fig. 3 is a system diagram showing the state during regeneration, and Fig. 4 is a system diagram when a plurality of l-manufacturing devices are used. FIG. 5 is a sectional view of a gas purifier showing another embodiment of the present invention. 1.1'... Gas purifier, 2... Housing, 6...
... Inlet, 7... Outlet, 9... Adsorbent, 11.
...First filter, 12...Second filter, 15...
・Reaction chamber. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 20 Figure 3 Figure 4

Claims (5)

[Claims] (1) A gas purifier connected to the gas intake side of a reaction chamber in a semiconductor manufacturing process, which includes a housing equipped with a gas inlet and an outlet, and a gas purifier for impurity gas removal housed within the housing. an adsorbent; a first filter provided in the housing between the inlet and the adsorbent; and a particulate-collecting filter provided in the housing between the adsorbent and the outlet. 1. A gas purifier for semiconductor manufacturing equipment, comprising: a high-density second filter. (2) The gas purifier for semiconductor manufacturing equipment according to claim 1, wherein the second filter is cylindrical, and the outer periphery of the second filter is filled with the adsorbent. (3) The gas purifier for semiconductor manufacturing equipment according to claim 1, wherein the second filter is made of ceramic. (4) The gas purifier for semiconductor manufacturing equipment according to claim 1, wherein the second filter is made of conductive ceramic. (5) The gas purifier for semiconductor manufacturing equipment according to claim 1, wherein the second filter is made of metal.