Porous member having ceramic particle and its manufacturing method

Abstract

To provide a porous member having ceramic particles which suppresses generation of particles and has good gas permeability and low pressure loss, and to provide a method for manufacturing the same.SOLUTION: The porous member having ceramic particles according to the present invention includes: a cylindrical housing 2 open at both ends; a plurality of ceramic particles 3 filled inside the housing; and a pair of porous lids 4 that seal both ends of the cylindrical housing and confine the ceramic particles inside the housing.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a porous member provided with ceramic particles and a method for manufacturing the same, and more particularly to a porous member provided with ceramic particles in which a housing is filled with ceramic particles and both ends of the housing are sealed with porous lids, and a method for manufacturing the same.

Background Art

[0002] In semiconductor manufacturing apparatuses that require extremely high cleanliness, filters made of various materials are used to remove particles and the like. Among them, ceramic filters are particularly widely used because they are excellent in terms of heat resistance, durability, corrosion resistance, and the like. A ceramic filter is composed of a ceramic porous body. For example, a ceramic porous body applicable as a member for semiconductor processing is disclosed in Patent Document 1. The member for semiconductor processing disclosed in Patent Document 1 is formed of a ceramic porous sintered body in which the porosity of the skeleton portion produced by agitation foaming is 5% or less and the overall porosity is 50% or more.

[0003] By the way, since a ceramic filter is a porous body and thus particularly low in brittleness and there is a risk of chipping during its handling, a housing is attached to facilitate its handling before it is incorporated into a semiconductor manufacturing apparatus. That is, a ceramic porous body main body having communicating bubbles is housed in a housing (such as a hollow cylindrical outer tube) for incorporation into a semiconductor manufacturing apparatus.

[0004] Patent Document 2 discloses a method for manufacturing a composite member including a ceramic porous body and a ceramic dense body surrounding the same. Specifically, when integrating a ceramic porous body and a ceramic outer surrounding member surrounding the same, a sintered body is used as the ceramic porous body, and a preliminarily fired molded body is used as the ceramic outer surrounding member, and the porous body and the outer surrounding member are assembled. Then, by subjecting this to main firing, due to the mechanical bonding force caused by the sintering shrinkage of the outer member formed body and the sintering of the porous body and the outer member, the ceramic porous body and the ceramic dense body surrounding it are integrated to manufacture a composite member.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, as disclosed in Patent Document 2, in a method for manufacturing a composite member composed of a ceramic porous body and a ceramic dense body surrounding it, the ceramic porous body of the main body part is a ceramic porous sintered body produced by agitation foaming, similar to the ceramic porous body disclosed in Patent Document 1. However, in the case of a porous body produced by agitation foaming with a porosity of 50% or more, the skeleton part of the pores where the bubble - like pores communicate with each other has to be extremely thin, and there is a problem that particles are likely to be generated due to grain detachment. On the other hand, if it is manufactured so as not to have a thin part in order to suppress the generation of particles, the porosity becomes small and the air permeability deteriorates. Even when it is attached to the exhaust part of the device, etc., a new problem occurs that it takes time for exhaust.

[0007] Also, when the ceramic porous body main body is housed in a housing, in the method disclosed in Patent Document 2, the ceramic porous body may be broken during firing at the part where the ceramic cylinder and the ceramic porous body are in contact.

[0008] The present invention has been made in view of the above circumstances, and has studied a new porous member and a method for manufacturing the same without using a ceramic porous sintered body produced by stirring and foaming, and has conceived and completed the present invention.

[0009] The present invention relates to a new porous member using ceramic particles and a method for manufacturing the same, and aims to provide a porous member provided with ceramic particles capable of suppressing the generation of particles or having good air permeability and low pressure loss, and a method for manufacturing the same.

Means for Solving the Problems

[0010] The porous member provided with ceramic particles according to the present invention for solving the above problems includes a cylindrical housing having both ends open, a plurality of ceramic particles filled in the housing, and a pair of porous lids that seal both ends of the cylindrical housing and confine the ceramic particles inside the housing.

[0011] The porous member provided with ceramic particles configured as described above is not a porous body produced by stirring and foaming, but is composed of a plurality of ceramic particles filled in the housing. Therefore, there is no thin-walled portion that occurred when the conventional porous body main body was formed by stirring and foaming, and problems such as particle generation due to the peeling of the thin-walled portion can be suppressed. Alternatively, the porous member provided with ceramic particles according to the present invention can obtain good air permeability and reduce pressure loss by setting the average pore diameter of the porous lid and the particle diameter of the ceramic particles within a specific range.

[0012] Here, it is desirable that the particle diameter of the ceramic particles is 100 μm or more and 800 μm or less. Further, it is desirable that the filling area ratio of the ceramic particles is 34% or more and 95% or less with respect to the length connecting both ends of the housing. Also, it is desirable that the average pore diameter of the porous lid is 22 μm or more and 200 μm or less, and the porosity is 20% or more and 40% or less.

[0013] Thus, by setting the particle size of the ceramic particles to be 100 μm or more and 800 μm or less, more preferably 600 μm or more and 800 μm or less, setting the filling area ratio of the ceramic particles to the housing to be 34% or more and 95% or less with respect to the length connecting both ends of the housing, and setting the average pore diameter of the porous lid to be 22 μm or more and 200 μm or less, the air permeability can be improved and the pressure loss can be reduced.

[0014] Further, in order to solve the above problems, in the method for manufacturing a porous member including the ceramic particles according to the present invention, a step of filling a plurality of ceramic particles into a cylindrical housing having both ends open, and a step of sealing both ends of the cylindrical housing with a pair of porous lids to confine the ceramic particles inside the housing are provided. According to such a method, a porous member including the ceramic particles of the present invention can be manufactured.

Advantages of the Invention

[0015] According to the present invention, it is possible to obtain a porous member including ceramic particles that can suppress the generation of particles, or has good air permeability and low pressure loss, and a method for manufacturing the same.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0017] Hereinafter, a porous member including ceramic particles according to the present invention and a method for manufacturing the same will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing the configuration of a porous member including ceramic particles according to the present invention. The porous member 1 including the ceramic particles shown in FIG. 1 can be used, for example, as a ceramic filter using continuous pores, a heat insulating material using a structure including pores, a light diffusing plate for uniformly spreading and transmitting light, or a member for a semiconductor manufacturing apparatus used in a plasma processing step or the like.

[0018] The porous member 1 including the ceramic particles in FIG. 1 includes a cylindrical outer cylinder member 2 having both ends open, ceramic particles 3 filled in the outer cylinder member 2, and a pair of porous lid bodies 4 for sealing both ends of the outer cylinder member 2. That is, it is configured such that the ceramic particles 3 are accommodated and filled in the outer cylinder member 2 as a housing.

[0019] The outer cylinder member 2 is preferably formed of a resin having high heat resistance, a resin having a low dielectric constant (for example, Teflon (registered trademark)), or quartz. For example, the diameter (outer diameter) d1 is 50 mm, the length L is 80 mm, and the thickness t1 is 5 mm. The outer cylinder member 2 is not limited to a cylindrical shape, and may have a rectangular tube shape with a polygonal cross section.

[0020] The ceramic particles 3 filled in the outer cylinder member 2 are simply in a state of being accommodated and filled in the outer cylinder member 2. The ceramic particles 3 are preferably formed of silica, and preferably have a crushed powder shape or a spherical shape. In addition, the filling region ratio of the ceramic particles 3 in the outer cylinder member 2 is 34% or more and 95% or less with respect to the length L connecting both ends of the outer cylinder member 2. Note that the filling region ratio means the length between a pair of porous lid bodies inside the outer cylinder member with respect to the length L connecting both ends of the outer cylinder member 2, that is, the length filled with ceramic particles. Here, when the length L connecting both ends of the outer cylinder member 2 is determined to be a specific length, if the filling region ratio decreases, the ratio (length) of the porous lid body 4 increases. On the other hand, if the filling region ratio increases, the ratio (length) of the porous lid body 4 decreases.

[0021] When the filling area ratio of the ceramic particles 3 in the outer cylinder member 2 is less than 34%, the ratio of the porous lid 4 to the length L connecting both ends of the outer cylinder member 2 increases, and there is a risk that the pressure loss will increase. Also, when the filling area ratio of the ceramic particles 3 in the outer cylinder member 2 exceeds 95%, the ratio of the porous lid 4 to the length L connecting both ends of the outer cylinder member 2 becomes small, and there is a risk that the porous lid 4 will be damaged.

[0022] The ceramic particles 3 preferably have a maximum particle size of 800 μm or less. When the maximum particle size exceeds 800 μm, the gaps between the particles become large, the gripping force between the particles becomes weak, the particles are likely to move within the outer cylinder member, and there is a risk of damaging (breaking) the porous lid. Also, when used as a light diffusing plate or a heat insulating material, the heat insulating effect and the light diffusing effect may be weakened. Also, in order to suppress the pressure loss, the minimum particle size of the ceramic particles 3 is preferably 100 μm or more, more preferably 600 μm or more. Therefore, the desirable range of the particle size of each ceramic particle 3 is 100 μm or more and 800 μm or less, more preferably 600 μm or more and 800 μm or less.

[0023] In addition, the ceramic particles 3 can be classified by a sieve. For example, the ceramic particles of 600 μm or more and 800 μm or less can be classified by using sieves with mesh sizes of 600 μm and 800 μm. That is, the ceramic particles of 600 μm or more and 800 μm or less can be obtained as the ceramic particles that pass through the sieve with a mesh size of 800 μm and do not pass through the sieve with a mesh size of 600 μm.

[0024] Also, a pair of porous lids 4 for sealing the both end openings of the outer cylinder member 2 and confining the ceramic particles 3 inside the outer cylinder member 2 are formed of a porous resin or silica. The outer peripheral portion of the porous lid 4 is joined to the inner peripheral surface of the outer cylinder member 2. Specifically, counterboring portions 2a are formed on the inner peripheral surfaces of both end portions of the outer cylindrical member 2, and the adhesive 5 is filled on the side surfaces of the counterboring portions 2a. That is, the porous lid 4 is joined to the inner peripheral surface of the outer cylindrical member 2 via the adhesive 5. Here, the case where the counterboring portions 2a are formed on the inner peripheral surfaces of both end portions of the outer cylindrical member 2 is shown. However, it is not particularly limited to the counterboring portions 2a, and a stepped portion where the adhesive 5 is filled may be formed on the porous lid 4 side, or they may be joined without forming a stepped portion on either the outer cylindrical member 2 or the porous lid 4. In addition, the adhesive 5 is not particularly limited as long as it has heat resistance. For example, epoxy-based or silica-based adhesives can be used. When the porous lid 4 is formed of resin, it can be formed of, for example, PTFE. When the porous lid 4 is formed of silica, it can be formed by, for example, the sol-gel method.

[0025] The average pore diameter of the porous lid 4 is preferably 22 μm or more and 200 μm or less, and the porosity is 20% or more and 40% or less. When the average pore diameter is less than 22 μm or the porosity is less than 20%, good air permeability cannot be obtained, and there is a risk that the pressure loss will increase. On the other hand, when the average pore diameter exceeds 200 μm or the porosity exceeds 40%, the risk of particle generation increases. In addition, the average pore diameter and porosity of the porous lid can be obtained by measuring them using a mercury porosimeter in the same manner as the average pore diameter and porosity of the porous body.

[0026] In addition, it is desirable that the ratio of the average pore diameter of the porous lid to the particle diameter of the ceramic particles is 1:1.1 to 1:80. When the ratio of the average pore diameter of the porous lid to the particle diameter of the ceramic particles is 1:1.1 to 1:80, good air permeability can be obtained, and the pressure loss can be reduced.

[0027] Further, the thickness t2 of the porous lid 4 is preferably formed to be 2 mm or more and 20 mm or less per sheet. If the thickness t2 of the porous lid 4 is less than 2 mm, the strength becomes weak and there is a risk of breakage. On the other hand, if the thickness t2 of the porous lid 4 exceeds 20 mm, there is a risk of increased pressure loss. In addition, the planar shape of the porous lid 4 is formed in accordance with the cross-sectional shape of the outer cylindrical member 2.

[0028] The porous member 1 configured in this way does not have a porous body produced by stirring and foaming, and is formed by a plurality of ceramic particles 3 filled in the outer cylindrical member 2. Furthermore, since the porosity of the porous lid 4 that seals both ends of the outer cylindrical member 2 is 20% or more and 40% or less, there is no thin-walled portion that occurred when forming a conventional porous body main body by stirring and foaming, and problems such as particle generation due to its degranulation are suppressed.

[0029] In particular, the particle size of the ceramic particles 3 is preferably 100 μm or more and 800 μm or less, more preferably 600 μm or more and 800 μm or less. The filling area ratio of the ceramic particles 3 to the outer cylindrical member 2 is 34% or more and 95% or less with respect to the length L connecting both ends of the outer cylindrical member 2. The average pore diameter of the porous lid 4 is preferably 22 μm or more and 200 μm or less, more preferably 22 μm or more and 150 μm or less. By doing so, the air permeability can be improved and the pressure loss can be reduced.

[0030] Also, since the ceramic particles 3 filled in the outer cylindrical member 2 are simply accommodated and filled in the outer cylindrical member 2, a large gap does not occur between the outer cylindrical member 2 and the ceramic particles 3. Further, since the ceramic particles 3 are not fired after being accommodated and filled in the outer cylindrical member 2, breakage of the ceramic particles 3 in close contact with the outer cylindrical member 2 can be prevented. Note that the ceramic particles 3 filled in the outer cylindrical member 2 may be fixed. As a fixing method, a method of filling in a state where a photocurable adhesive or the like is previously applied to the ceramic particles 3 can be used. By fixing the ceramic particles 3, they will not be deflected even when vibration is applied after filling.

[0031] Next, a method for manufacturing a porous member including ceramic particles according to the present invention will be described with reference to FIG. 2. First, counterbores 2a are formed on the inner peripheral surfaces at both ends of an outer cylindrical member 2 made of a highly heat-resistant resin (e.g., Teflon) or quartz. The outer cylindrical member 2 is formed, for example, with a diameter (outer diameter) d1 of 50 mm, an inner diameter d3 of 40 mm, a length L of 80 mm, a thickness t1 of 5 mm, a diameter d2 of the counterbore 2a of 42 mm, and a depth t2 of 5 mm. Then, as shown in FIG. 2(a), an epoxy-based adhesive 5 is applied to the side surface of the counterbore 2a of the porous member 1, and as shown in FIG. 2(b), the porous lid 4 is attached to the porous member 1 and dried at 80° C. for 3 hours.

[0032] Note that the porous lid 4 is formed in advance such that the outer shape of the porous lid 4 in plan view conforms to the shape of the counterbore 2a of the outer cylindrical member 2, the outer diameter of the porous lid 4 substantially matches the inner diameter of the counterbore 2a of the outer cylindrical member 2, and the porous lid 4 can be fitted to the end of the outer cylindrical member 2.

[0033] Next, as shown in FIG. 2(c), the outer cylindrical member 2 is placed upside down on a vibrator 10 (e.g., product name: VIBRATORY PACKER). As a result, the porous lid 4 (4A) joined previously is disposed at the bottom of the outer cylindrical member 2. Then, ceramic particles 3 are introduced into the outer cylindrical member 2 until they are at the same position as the bottom surface of the counterbore 2a.

[0034] Next, the vibrator 10 is operated and vibrated at a frequency of 60 Hz for about 1 minute. When the upper surface of the introduced ceramic particles drops, the ceramic particles are added and replenished, and the vibrator 10 is operated again at a frequency of 60 Hz for about 1 minute. Further, the addition and replenishment of the ceramic particles and the vibration by the vibrator 10 are repeated until the upper surface of the introduced ceramic particles after vibration is at the same position as the bottom surface of the counterbore 2a. As a result, large gaps between the ceramic particles 3 filled in the outer cylindrical member 2 are eliminated, and the gaps between the ceramic particles 3 are made uniform.

[0035] Then, as shown in Fig. 2(d), a epoxy-based adhesive 5 is applied to the side surface of the countersunk portion 2a of the porous member 1, the porous lid 4 (4B) is attached to the porous member 1, and dried at 80 °C for 3 hours. By carrying out the above steps, the porous member 1 provided with the ceramic particles shown in Fig. 1 is manufactured.

[0036] In this way, the manufactured porous member is charged with ceramic particles 3 having a particle size of 100 μm or more and 800 μm or less, more preferably 600 μm or more and 800 μm or less, and finally the filling region ratio of the ceramic particles 3 in the outer cylindrical member 2 is set to be 34% or more and 95% or less with respect to the length L connecting both ends of the outer cylindrical member 2.

Example

[0037] Hereinafter, a porous member provided with ceramic particles according to the present invention and a method for manufacturing the same will be further described based on examples.

[0038] (Example 1) In Example 1, the porous member 1 provided with the ceramic particles having the structure shown in Fig. 1 was used. As specific conditions, the particle size of the ceramic particles 3 was 600 to 800 μm (average particle size 700 μm). The outer cylindrical member 2 had a diameter (outer diameter) d1 of 50 mm, an inner diameter d3 of 40 mm, a length L of 80 mm, a thickness t1 of 5 mm, a diameter d2 of the countersunk portion 2a of 42 mm, and a depth t2 of 5 mm. The filling region ratio of the ceramic particles in the outer cylindrical member 2 was 88% with respect to the length L connecting both ends of the outer cylindrical member 2. In addition, the porous lid 4 was formed of silica by the sol-gel method, with an average pore diameter of 38 μm and a porosity of 40%. The outer shape of the porous lid 4 in plan view was made to conform to the shape of the countersunk portion 2a of the outer cylindrical member 2, and the outer diameter of the porous lid 4 was formed in advance so as to substantially coincide with the inner diameter of the countersunk portion 2a of the outer cylindrical member 2, enabling the porous lid 4 to be fitted to the end of the outer cylindrical member 2.

[0039] N2 gas was introduced into the porous member 1 at a flow rate of 50 ml (milliliters) / min (minute) from the porous lid 4A at one end of the porous member 1, and discharged from the porous lid 4B at the other end of the porous member 1 to measure the pressure loss (Pa). For the measurement, the line shown in FIG. 3 was used. While observing the flow meter, nitrogen was flowed at a predetermined flow rate, and the pressure loss was evaluated by reading the differential pressure at that time with a differential pressure gauge. Also, the number of particles detected per minute was counted using an airborne particle counter to evaluate the particles. The results of Example 1 are shown in Table 1.

[0040] (Comparative Example 1) As Comparative Example 1, silica powder (average particle size: 600 μm) was used to form a cylindrical porous body with an average pore diameter of 150 μm, a diameter of 40 mm × a length of 80 mm by the sol-gel method, which was inserted into an outer cylindrical member having the same shape as in Example 1 (diameter d1 is 50 mm, inner diameter d3 is 40 mm, length L is 80 mm), and the pressure loss and the number of particles were measured under the same conditions as in Example 1. The results of Comparative Example 1 are shown in Table 1.

[0041] (Examples 2 to 9) The average pore diameter of the porous lid and the particle size of the ceramic particles were changed as shown in Table 1, and the particles were evaluated by counting the number of particles in the same manner as in Example 1 for the others. Also, N2 gas was introduced into the porous member 1 at a flow rate of 50 ml (milliliters) / min (minute) from the porous lid 4A at one end of the porous member 1, and discharged from the porous lid 4B at the other end of the porous member 1 to measure the pressure loss (Pa).

[0042]

Table 1

[0043] In any of Examples 1 to 9, no large gap occurred between the housing and the ceramic particles, and no breakage was observed in the housing and the ceramic particles. In addition, in Examples 1 to 9 except for Examples 4 and 9, as shown in Table 1, the pressure loss at the N2 gas flow rate of Example 1 was lower than that of Comparative Example 1 (conventional porous body). Also, in any of Examples 1 to 9, the number of particles generated was equal to or less than that in Comparative Example 1. In particular, in Examples 1 to 9 except for Examples 4 and 9, both a decrease in the number of particles generated and a decrease in differential pressure were observed in Comparative Example 1.

[0044] (Examples 10 to 13) The average pore diameter of the porous lid and the filling area ratio of the ceramic particles were changed as shown in Table 2, and the others were the same as in Example 1. The particles were evaluated by counting the number of particles. Further, N2 gas was introduced into the porous member 1 from the porous lid 4A at one end of the porous member 1 at a flow rate of 50 L / min, and the pressure loss (Pa) was measured by discharging it from the porous lid 4B at the other end of the porous member 1. The results are shown in Table 2.

[0045]

Table 2

[0046] In any of Examples 10 to 13, no large gap occurred between the housing and the ceramic particles, and no breakage was observed in the housing and the ceramic particles. As shown in Table 2, when the filling area ratio of the ceramic particles was 34% to 95% (Examples 11 to 13), a decrease in differential pressure was observed compared to Comparative Example 1.

[0047] (Examples 14 to 20) The average pore diameter and porosity of the porous lid were changed as shown in Table 3, and the other conditions were the same as in Example 1. The particles were evaluated by counting the number of particles. Also, N2 gas was introduced into the porous member 1 from the porous lid 4A at one end of the porous member 1 at a flow rate of 50 ml (milliliters) / min (minute), and the pressure loss (Pa) was measured by discharging it from the porous lid 4B at the other end of the porous member 1. The results are shown in Table 3.

[0048]

Table 3

[0049] In any of Examples 14 to 20, no large gap occurred between the housing and the ceramic particles, and no breakage was observed in the housing and the ceramic particles. Also, as shown in Table 3, when either the average pore diameter of the porous lid was 22 μm to 200 μm or the porosity of the porous lid was 20 to 45%, a decrease in the number of generated particles or a decrease in the differential pressure was observed compared to Comparative Example 1.

Explanation of Signs

[0050] 1 Porous member provided with ceramic particles 2 Outer cylinder member (housing) 3 Ceramic particles 4 Porous lid

Claims

1. A cylindrical housing with both ends open, A plurality of ceramic particles filled in the housing, A pair of porous lids that seal both ends of the cylindrical housing and confine the ceramic particles inside the housing, A porous member comprising ceramic particles, characterized in that it comprises the above.

2. The porous member comprising ceramic particles according to Claim 1, wherein the particle size of the ceramic particles is 100 μm or more and 800 μm or less.

3. The porous member comprising ceramic particles according to Claim 1 or 2, wherein the filling area ratio of the ceramic particles is 34% or more and 95% or less with respect to the length connecting both ends of the housing.

4. The porous member comprising ceramic particles according to Claim 1, wherein the average pore diameter of the porous lid is 22 μm or more and 200 μm or less, and the porosity is 20% or more and 40% or less.

5. In the method for manufacturing a porous member comprising ceramic particles according to any one of Claims 1 to 4, A step of filling a plurality of ceramic particles into a cylindrical housing with both ends open, A step of sealing both ends of the cylindrical housing with a pair of porous lids and confining the ceramic particles inside the housing, A method for manufacturing a porous member comprising ceramic particles, characterized in that it comprises the above.

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