JP2004305964A - Filter device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter device which can appropriately be used, for example, for filtering a process gas for manufacturing semiconductors. <P>SOLUTION: The filter device seals the peripheral part of a filtration member including a filtration layer having fine pores and a support layer which supports the filtration layer, is loaded with filtration pressure, and has pores larger than those of the filtration layer by using a first press member forming an inlet space in which treatment fluid flows and a second press member forming an outlet space into which treated fluid filtered by the filtration layer is supplied. The first press member is composed of a rigid press base part having an end surface turned to the periphery and an elastic member arranged along the peripheral part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a filter device that can be suitably used for, for example, a filtration process of a process gas or the like for manufacturing a semiconductor.
[0002]
[Prior art]
For semiconductors, with the recent technological innovation and improvement in the precision of peripheral equipment, products are becoming more and more compact, and various process gases used in the manufacturing process are also reduced to ultra-fine particles of, for example, 0.1 μm, in the nano range of 10 ⁻¹⁰ or less. It is required to have a high level of high purity to be reduced.
[0003]
In general, as filter products suitable for such applications,
a) The filter should have the required filtration diameter with low pressure loss and excellent filterability with no stagnation.
b) excellent corrosion resistance to the gas to be treated, etc.
c) having heat resistance to withstand the baking process of the system;
d) It is required to have properties such as workability capable of performing necessary machining such as welding. Therefore, metal filter media have been widely adopted, and the present inventor has used, for example, stainless steel short fibers. Various filtration members, filter devices, and the like have been proposed.
[0004]
For example, Patent Literature 1 proposes a laminated filtration member formed by laminating, sintering, and integrating a particle layer made of particles finer than the pore diameter of the support on a support made of a porous metal material. Short metal fibers having an average aspect ratio (L / d) of 2 to 15 are suspended without using a binder, and vacuum filtration is performed to form a filter layer on a support. According to this filtration member, substantial filtration is performed by the filtration layer, and strength maintenance can be performed by the support, so that the filtration layer can be made to a minimum necessary thickness, and high pore accuracy and Excellent function with low pressure loss.
[0005]
In the filter member according to this proposal, since the filter layer is formed of short metal fibers having a predetermined aspect ratio, each short fiber is randomly distributed three-dimensionally to increase porosity and improve filtration characteristics. It is considered possible.
[0006]
On the other hand, as a filter device in which such a laminated filter medium is incorporated into a housing container and integrated, for example, Patent Document 2 proposes an in-line type filter device interposed between gas pipes facing each other as illustrated in FIG. In this filter device, the laminated filtering member a is disposed between the first case member b and the second case member c to which the spigot-fitting is to be fitted, and the outer peripheral portion is welded along the welding line d. Thereby, the laminated filtration member a is reliably sealed by heat shrinkage after welding.
[0007]
In Patent Document 3, as shown in FIG. 8, an inlet e and an outlet f are provided on one surface of a block-shaped second case member c, on which one side of the fluid to be treated flows in and out, and the other surface. The filter member a is interposed between the inlet space communicating with the inflow port e and the outlet space communicating with the outflow port f by closing the recess formed in the above by the first case member b partitioned by the filtering member a. And the fluid to be processed is filtered out from the outlet f.
[0008]
In particular, in the filter device of Patent Document 3, since the inflow port e and the outflow port f are provided on one surface side of the second case member b, which is a base, one sheet in which a circuit (flow path) is formed in advance is provided. By arranging together with various parts such as valves and regulators on the panel P, a filter device referred to as an integrated type in the present specification which can constitute an integrated gas supply system is formed. Space and maintainability can be improved.
[0009]
[Patent Document 1] Japanese Patent No. 2857494 [Patent Document 2] Japanese Patent No. 2813274 [Patent Document 1] Japanese Patent Application Laid-Open No. 11-165012
These in-line type and integrated type filter devices according to Patent Documents 2 and 3 are mainly intended to be suitably used for filtering high-purity gas for semiconductor production. It is necessary to prevent the leakage of the fluid to be processed between the two and to reliably seal.
[0011]
By the way, for example, the sealing structure of the inline type filter device illustrated in FIG. 7 is interposed between the two case members b and c for pressing the filter member a as described above, and the outer periphery of the case members b and c. When welding is performed at the welding line d while pressing the filter member a away from the filter member a, the filter member a can be pressed by the heat shrinkage after the welding, and the heat shrinkage can be effectively used, so that A good sealing property can be obtained.
[0012]
On the other hand, in the integrated filter device illustrated in FIG. 8, as shown in an enlarged view in FIG. 9, for example, the filter member a is provided with a step g provided in a second case member c, It is arranged between the case member b and presses the first and second case members b and c, sandwiches the filter member a therebetween, and welds along the welding line d.
[0013]
[Problems to be solved by the invention]
However, in the sealing structure shown in FIG. 9, the heat shrinkage after welding acts in a direction to loosen the pressing force of the filter member a, and as a result, the step g of the second case body c and the step g of the second case body c are supported by the step g. In order to maintain the sealing property between the laminated filtration member a and the filtration layer, strict control including the pressing force, the amount of distortion due to the pressing force, and the amount of heat shrinkage is required.
[0014]
An object of the present invention is to provide a filter device capable of improving a seal structure on the basis of using an elastic member.
[0015]
[Means for Solving the Problems]
The invention according to claim 1 of the present invention is directed to a laminated filtration member including a filtration layer having fine pores and a support layer that supports the filtration layer and bears a filtration pressure and has pores larger than the filtration layer. A filter device that seals a peripheral portion using a first pressing member forming an inlet space into which a fluid to be processed flows and a second pressing member forming an outlet space into which a processing fluid filtered by the filtration layer enters. So,
The laminated filtering member is arranged with the support layer facing the first pressing member, and an elastic member is interposed between the first pressing member and the supporting layer, whereby the second pressing member is provided. It is characterized in that the sealing property between the filter and the filter layer is improved.
[0016]
The invention according to claim 2 is characterized in that the elastic member has a first pressing member that increases in accordance with heat shrinkage after the welding in an assembled state by welding the first pressing member and the second pressing member, The invention according to claim 3, wherein the elastic member is formed of a metal fiber sintered sheet by absorbing a gap between the support layer and the sealing member between the second pressing member and the filtration layer. In the invention according to claim 4, the elastic member is formed by forming a narrow spring plate that repeats peaks and valleys in a direction perpendicular to the plate surface, on a side facing each other of adjacent winding layers. Each of the springs is a spirally wound spring in which a peak and a valley protruding from the spring are brought into contact with each other.
[0017]
The invention according to claim 5 is characterized in that the second pressing member has a concave portion provided with an inflow port and an outflow port on one surface and a step portion supporting a filtering member on another surface, The first pressing member includes a peripheral wall portion that fits into the recess around the top plate portion, and the peripheral wall portion interposes the support layer of the laminated filtering member placed on the step portion by the fitting through the elastic member. And pressing the first pressing member and the second pressing member by welding. The invention according to claim 6, wherein the filtering member is configured to filter a process gas for manufacturing a semiconductor. The invention according to claim 7, which is a filter member for a process gas used for processing, is characterized in that the filter member has a peripheral thin portion whose peripheral edge is reduced in advance by pressing.
[0018]
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, an embodiment of the present invention will be described with reference to the drawings, taking as an example a case where the filter device 1 of the present invention is configured as an integrated filter device. 1 is a cross-sectional view of a filter device 1 of the present invention, FIG. 2 is a bottom view thereof, FIG. 3 is an exploded perspective view thereof, and FIG. 4 is an enlarged cross-sectional view. A filter member 2), and first and second pressing members 4 and 5 which can seal the filtering member 2 and form a housing 3, and the first pressing member 4 is An elastic member 9 is provided between the filter member 2 and the support layer 2B.
[0019]
As shown schematically in FIG. 4, the filter member 2 has a filter layer 2A having fine pores, a filter layer 2A having pores larger than the filter layer 2A, and capable of withstanding a large filtration pressure without deformation. It is composed of a laminate obtained by integrating a relatively thick porous support layer 2B capable of supporting 2A. Such a filter member 2 of the laminated type can be manufactured by, for example, laminating a previously prepared fine layer sheet and a porous plate-like body and sintering them together, but is preferably proposed by the above-mentioned Patent Document 1. On the support layer 2B having relatively large pores and thickness, a filtration layer 2A composed of a fine powder layer and substantially used for filtration is formed by a suspension suction method and formed by sintering and integration. A filter material formed by a filtering member molding method can be used.
[0020]
The filtering member 2 by such a manufacturing method is
a) Since no foreign material such as a binder is used, no impurities are generated and the material is clean.
[0021]
b) The fine particles used can be arbitrarily selected.
[0022]
c) Since the molding thickness of the fine layer is formed by vacuum suction from the suspension, it can be formed with the minimum necessary thickness.
[0023]
d) The pore characteristics of the formed filtration layer can also be homogenized as a whole.
[0024]
e) Since it is a porous metal body, it has high compression resistance, adapts well when pressed for sealing, does not break or crack, and contributes to the improvement of the life of the filter device.
[0025]
Since it has many advantages, it can be suitably used particularly for applications requiring high purity and high precision filtration such as semiconductor gas.
[0026]
The filtering member 2 is made of, for example, a metal powder, a metal fiber, a metal short fiber, or the like that satisfies properties such as strength, corrosion resistance, heat resistance, and toughness when pressed. Filter materials made of metal such as these alloys, stainless steel, and titanium alloys are used. In particular, those in which the stainless steel short fiber is used as a filtration layer can be suitably used.
[0027]
In addition, the filter member 2 includes, in addition to those in which the lamination of the filter layer 2A and the support layer 2B can be clearly recognized, for example, those in which the pore characteristics gradually change with a gradient between both surfaces, In addition, it is also possible to use those obtained by simply superposing and laminating each layer without integrating each layer.
[0028]
In the present embodiment, the support 2B is made of, for example, an atomized powder of Ni-based stainless steel (about # 140/200 to 200/250 mesh) with a thickness of 2 mm, an outer diameter of 20 mm, an average pore diameter of 10 μm, and a porosity of 40. %. Fine particles are used for the filtration layer 2A, and as the fine particles, for example, stainless steel short fibers cut to a diameter of 1 to 20 μm and an average aspect ratio of about 2 to 20 are used. The pore characteristics of the filtration layer 2A were an average pore diameter of 1.8 μm, a formed thickness of 0.3 mm, and an average porosity of 58%. Further, in the present embodiment, the peripheral portion 2a of the filter member 2 in which the filter layer 2A and the support 2B are laminated and integrated is pressed in advance to form the peripheral thin portion 2b which is densely reduced to improve the support accuracy. However, a structure without such a thin portion 2b can also be used.
[0029]
Further, when the short fibers of the stainless steel are, for example, the short fibers according to Japanese Patent Publication No. 63-63645, there is no substantial cutting sag at the end, so that the short fibers are easily entangled with each other. There is an advantage that the porosity can be increased even though the pores are fine pores. If necessary, the staple fiber may be mixed with another atomized fine powder, or may be formed of only the atomized powder.
[0030]
Furthermore, in order to increase the filtration area, for example, the filtering member 2 has pleats and irregularities formed on at least a part of the surface of the support 2B, leaving a peripheral portion 2a in order to increase the filtration area. The surface of the 2A may be deformed into irregularities to expand the filtration area, and the central portion may be overmolded into a cup shape or a hemisphere shape while leaving the peripheral portion 2a. As the support layer 2B, for example, a foamed metal porous body, a metal fiber sintered body, or the like can be used.
[0031]
On the other hand, the second pressing member 5 is formed of a block-shaped base having an inlet 5b and an outlet 5c on one surface, that is, one surface (the bottom surface in the case of FIG. 1), through which the fluid to be treated flows in and out. On the other surface, the other surface (the upper surface in the case of FIG. 1) opposite to the one surface in the present embodiment, a seat surface which is open at the other surface and projects inward in the radial direction for supporting the filtering member 2. The concave portion 12 having the step portion 5a having the shape is formed. The second pressing member 5 has an inlet channel 5d for communicating the inflow port 5b on the upstream side (upper surface side) of the step 5a in the concave portion 12, and on the downstream side of the step 5a. On the (bottom side), an outlet channel 5e communicating with the outlet 5c is formed.
[0032]
Further, as described above, the first pressing member 4 has the pressing base 7 for pressing the filtering member 2 to the step portion 5 a via the elastic member 9, and the pressing base 7 is provided on the top plate 13. The peripheral wall 15 is formed around the recess 12 so as to fit tightly into the recess 12. Further, the end face 15a of the peripheral wall portion 15 presses the peripheral edge portion 2a of the filter member 2 supported by the step portion 5a via the elastic member 9 as described above. Further, by fitting the peripheral wall portion 15 into the concave portion 12, the outer surface portion of the top plate portion 13 has the same height as the other surface of the second pressing member 5, and It is integrated by welding along a welding line d which is a boundary with the pressing base 7. The peripheral wall portion 15 is formed with a through hole 15b that allows the inlet flow path 5d to communicate with the inside of the concave portion 12.
[0033]
The elastic member 9 elastically presses the surface of the support layer B so as to improve the sealing property therebetween by pressing the filtration layer 2A of the filtration member 2 against the step portion 5a, More preferably, a material having a compression modulus lower than that of the support 2B is used. Here, the compressive elastic modulus means a slope which is a ratio of stress / strain in an elastic region in a compression test of a measured object. Here, when the support layer 2B is plastically deformed in advance, its state Means the compression modulus when recompressed in
Further, the elastic member 9 has an amount of bending that can keep the filter member 2 pressed against the step portion 5a due to heat shrinkage (heat shrinkage of the first pressing member 4) after welding, and the filter layer 2A and the step portion 5a due to pressing. The thickness and the compressive elasticity are set so as to have a pressing force that does not cause the fluid to be processed to leak from between. Further, by using the elastic member 9 having a low compression elastic modulus as the elastic member 9, breakage, cracking and the like of the filtering member 2 can be suppressed.
[0035]
As such an elastic member 9, an annular body formed by stamping a metal fiber sintered sheet into a ring shape having substantially the same width as the peripheral portion 2 a, or, for example, a peak portion in a direction orthogonal to the plate surface as shown in FIG. 5. m and a valley v are repeatedly abutted at a constant pitch in the circumferential direction with the ridges m and the valleys v projecting toward the mutually facing sides of the adjacent winding layers A and B. A spirally wound spring or the like can be used. Such a spring with a wave has been commercialized as a “wave spring” by, for example, Maruho Hakko Kogyo Co., Ltd. and Precision Spring Co., and has a large elastic generating force even when having a relatively large outer diameter. Thus, the filtering member 9 can be pressed more strongly and surely. The pressing force can be dispersed by reducing the corrugation angular pitch to, for example, about 5 to 15 degrees.
[0036]
FIG. 6 shows a sintered body 2B formed of stainless steel atomized powder of # 140/200 mesh as a support layer 2B of the filter member 2 to a porosity of 40% and a thickness of 1.8 mm, and a spring with a wave. This is an example of a qualitative comparison of the compressive elastic moduli of the elastic member 9A and the elastic member 9B made of a metal fiber sintered body. The sintered metal fiber sheet was obtained by randomly punching a stainless steel fiber having a fiber diameter of 8 μm and a sheet having a porosity of 70% and a thickness of 0.8 mm and a width of 1.5 mm. The elastic modulus of this sintered body was 1200 N / mm ² , whereas the support 2B made of the powder had a higher elastic modulus.
[0037]
The waved spring is formed by spring-forming a stainless steel strip having a width of 1.3 mm and a thickness of 0.5 mm with a predetermined pitch and having an outer diameter of 27 mm and two turns, and has a pressing displacement of about 2 mm. Things. The use of such an elastic member 9 is required to be sufficiently thicker than the heat shrinkage after welding, to press the filter member 2 with a constant force, to ensure the sealing of the filter layer 2A, and to have a small compression elastic modulus. Therefore, deformation of the filter medium itself can be prevented. Therefore, even if one of the pressing members, for example, the first pressing member 4 returns due to heat shrinkage or the like, the sealing pressure hardly changes, and the filtering pressure is stable. The maintained sealing performance can be maintained.
[0038]
The thickness of the elastic member 9 is set in consideration of the heat shrinkage due to welding, dimensional change, and the like. In addition, in consideration of the compressive strength of the elastic member 9, the thickness of the elastic member 9 is set at the peripheral portion 2a of the filter member 2 as described above. It is preferable to form the peripheral thin-walled portion 2b which is densely compressed in advance to increase the compression elastic modulus.
[0039]
As described above, according to the present invention, the laminated filter medium 2 is placed on the step portion 5 c on the inner surface of the concave portion 12 with the filter layer 2 A down, and the first pressing member 4 is fitted into the concave portion 12 via the elastic member 9. In addition, the filter device 1 can be configured by welding in a state where the filter device 1 is pressed with a predetermined pressing force. In this filter device 1, since the filtering member 2 presses the support layer 2B of the first pressing member 4 via the elastic member 9, the filtering layer 2A is deformed by the pressing member 4 interposed, The entire surface of the step portion 5a can be uniformly pressed without receiving the pressure, thereby improving the sealing performance. At this time, the presence of the elastic member 9 can prevent substantial loss of sealing performance even when pressure return occurs due to thermal contraction. Regarding the pore characteristics of the elastic member, regardless of the filtration layer, a sintered body having coarse pores or various forms such as the above-described wave spring are used, which contributes to cost reduction.
[0040]
In the filter device 1 of the present invention, as a result of ensuring the sealing property of the filtration layer 2A of the filtering member 2, the filter device of the present invention is an integrated type, for example, as shown in FIG. It can be attached to P by bolting or the like, but it can also be used in the case of an in-line type, and can be used for various fluids or applications other than for gas filtration of semiconductors. May be provided on the second pressing member 5 side.
[0041]
【The invention's effect】
As described above, the filter device of the present invention seals the filter layer side through the elastic layer on the support layer side of the filter member, and the sealing performance is impaired by the return of the pressing force due to the heat shrinkage after welding. In addition, mechanical sealing can be performed while suppressing breakage and cracking of the filtration layer itself due to suppression. In addition, it can be performed without strictly calculating the dimensional change rate accompanying complicated heat shrinkage, and can increase the production yield and production efficiency.For example, in a filter device in which pressing by heat shrinkage is difficult. Can also be suitably adopted. In addition, since the pressing member is disposed on the support layer side of the filtering member, it is not necessary to consider the pore characteristics of the pressing member itself, and various types and structures can be used. Is high.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an embodiment.
FIG. 2 is a bottom view thereof.
FIG. 3 is an exploded perspective view thereof.
FIG. 4 is an enlarged sectional view.
FIG. 5 is a perspective view showing an example of an elastic member.
FIG. 6 is a diagram comparing compression elastic moduli.
FIG. 7 is a partial cross-sectional view illustrating an in-line type filter device.
FIG. 8 is a cross-sectional view illustrating a conventional integrated filter device.
FIG. 9 is an enlarged sectional view thereof.
[Explanation of symbols]
2 Filtration Member 2A Filtration Layer 2B Support Layer 3 Housing 3A Inlet Space 3B Outlet Space 4 First Press Member 5 Second Press Member 5a Step 5b Inlet 5c Outlet 7 Press Base 9 Elastic Member 12 Recess 13 Ceiling 15 Surrounding wall

Claims (7)

The fluid to be treated flows into the periphery of the laminated filtration member including a filtration layer having fine pores and a support layer that supports the filtration layer and bears filtration pressure and has pores larger than the filtration layer. A filter device that seals using a first pressing member that forms an inlet space and a second pressing member that forms an outlet space into which the processing fluid filtered by the filtration layer enters,
The laminated filtering member is arranged with the support layer facing the first pressing member, and an elastic member is interposed between the first pressing member and the supporting layer, whereby the second pressing member is provided. A filter device having improved sealing properties between a filter and a filtration layer. The elastic member absorbs a gap between the first pressing member and the support layer, which increases with thermal contraction after the welding, in an assembled state by welding the first pressing member and the second pressing member. The filter device according to claim 1, wherein the sealing property between the second pressing member and the filtration layer is improved. The filter device according to claim 1, wherein the elastic member is an annular body made of a metal fiber sintered sheet. The elastic member, a peak portion, a valley portion in a direction orthogonal to the plate surface, a corrugated narrow spring plate that repeats the valley portion, the ridge portion projecting to the mutually facing side of the adjacent winding layer, the valley portion abuts. The filter device according to claim 1, wherein the filter device is a spirally wound spring. The second pressing member has an inflow port and an outflow port on one surface, and has a concave portion provided with a stepped portion for supporting a filtering member on the other surface, and the first pressing member has a top plate. A peripheral wall portion fitted into the recess around the portion, the peripheral wall portion pressing the support layer of the laminated filtration member placed on the step portion through the elastic member by the fit, and the first wall portion; The filter device according to claim 1, wherein the pressing member and the second pressing member are fixed by welding. The filter device according to any one of claims 1 to 5, wherein the filter member is a process gas filter member used in a process for filtering a process gas for manufacturing a semiconductor. The filter device according to any one of claims 1 to 6, wherein the filter member has a peripheral thin portion whose peripheral edge is reduced in advance by pressing.

Images