JP2021046511A - Fluororesin molded article - Google Patents

Abstract

To provide a fluororesin molded article that has less impurities contamination.SOLUTION: A fluororesin molded article containing a first part and a second part is provided. The first part contains a conductive filler and a tetrafluoroethylene resin. The second part is adjacent to the first part. The second part is made of tetrafluoroethylene resin.SELECTED DRAWING: Figure 2

Description

The present invention relates to a fluororesin molded product.

A fluororesin integrated tank made of a fluororesin such as tetrafluoroethylene resin (PTFE) is manufactured by an isostatic molding method. As isostatic molding method, for example, in Patent Document 1, after the isostatic compression molded at pressure conditions of polytetrafluoroethylene powder ^{1500kg / cm 2 ~10000kg / cm 2} , it is described that firing the molded body ..

On the other hand, the fluororesin integrated tank is molded by a rubber bag molding method, that is, a molding mold having a rubber film on one side is filled with PTFE molding powder, and then hydrostatic pressure is applied as a molding pressure to obtain a premolded product, which is then fired. It has been attempted to obtain it by a cooling method. In addition, it is also considered to form a fluororesin integrated tank by a method in which PTFE molding powder is filled between the outer mold and the inner mold and then pressed from above and below with a press.

Molded products obtained by compressing and firing PTFE molding powder include those made of virgin resin alone, that is, additive-free resin molded products. In addition, there is a molded product obtained by mixing a filler with a virgin resin. While the desired properties can be imparted to the molded product by adding a filler, a molded product made of virgin resin may be used depending on the use of the molded product. For example, virgin PTFE is used in parts for semiconductor cleaning equipment.

Examples of cleaning of electronic substrates such as semiconductor wafers and photomasks include physical cleaning such as ultrasonic cleaning and chemical cleaning using a chemical solution. Compared with physical cleaning, chemical cleaning has less load on the electronic substrate, and it is easy to properly dispose of fine dust. Therefore, when cleaning the electronic substrate, chemical cleaning is mainly performed.

For cleaning with a chemical solution, for example, a single-wafer cleaning device is used. In Patent Document 2, it was confirmed that the chemical solution was dropped on the wafer surface in a state where the wafer was stationary or rotated at a low speed, and that the way the chemical solution spreads on the wafer surface under the first chemical droplet was non-uniform. Then, a method of uniformly applying the chemical solution by dropping the chemical solution again at a position where the chemical solution has not spread is described.

The chemical solution dropped on the wafer in the single-wafer cleaning device spreads on the wafer by the centrifugal force generated by the rotation of the wafer. Excess chemicals are blown off the edges of the wafer. The blown chemical solution hits the inner wall surface of the cup provided in the device and then is drained. The cup can be, for example, a PTFE molded product. Since the chemical solution that hits the inner wall of the cup may bounce off the wafer, the filler may remain as an impurity on the wafer when a cup made of a molded product containing the filler is used. Wafers with residual impurities do not meet the required performance and may result in defective products.

In semiconductor cleaning equipment that requires a high degree of cleanliness for equipment and parts in this way, wafer contamination due to elution of metal ions and contamination, etc., becomes a problem, especially in wetted parts, so PTFE containing a filler is basic. It cannot be used. However, virgin PTFE is susceptible to static electricity. Therefore, even if attention is paid, dust, dust, dust, etc. in the air may adhere to the surface of the charged PTFE, which may lead to contamination of the wafer.

Japanese Unexamined Patent Publication No. 6-182791 Japanese Unexamined Patent Publication No. 2003-45768 Japanese Unexamined Patent Publication No. 62-108520

An object of the present invention is to provide a fluororesin molded product with less impurity contamination.

According to the present invention, a fluororesin molded product including a first part and a second part is provided. The first part contains a conductive filler and a tetrafluoroethylene resin. The second part is adjacent to the first part. The second part consists of a tetrafluoroethylene resin.

According to the present invention, it is possible to provide a fluororesin molded product with less impurity contamination.

The plan view which shows typically an example of the fluororesin molded article which concerns on embodiment. A cross-sectional view of the fluororesin molded product shown in FIG. 1 cut along the line II-II'. FIG. 3 is a schematic cross-sectional view showing the use of the fluororesin molded product of the example shown in FIG. FIG. 6 is a schematic cross-sectional view showing another example of the fluororesin molded product according to the embodiment. The schematic cross-sectional view which shows one step in the manufacturing method of the fluororesin molded article which concerns on embodiment. The schematic cross-sectional view which shows one step in the manufacturing method of the fluororesin molded article which concerns on embodiment. The schematic cross-sectional view which shows one step in the manufacturing method of the fluororesin molded article which concerns on embodiment. FIG. 7 is a cross-sectional view taken along the line VIII-VIII'shown in FIG. The schematic cross-sectional view which shows one step in the manufacturing method of the fluororesin molded article which concerns on embodiment. FIG. 9 is a cross-sectional view cut along the X-X'line shown in FIG. The schematic cross-sectional view which shows one step in the manufacturing method of the fluororesin molded article which concerns on embodiment. The schematic cross-sectional view which shows one step in the manufacturing method of the fluororesin molded article which concerns on embodiment. The schematic cross-sectional view which shows the unprocessed molded article obtained at the time of manufacturing the fluororesin molded article which concerns on embodiment. FIG. 3 is a schematic cross-sectional view showing the cutting process of the unprocessed molded product shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same reference numerals are given to common configurations throughout the embodiment, and duplicate description will be omitted. In addition, each figure is a schematic view for explaining the embodiment and promoting its understanding, and the shape, dimensions, ratio, etc. of the figure are different from those of the actual device. The design can be changed as appropriate by taking into consideration.

(First Embodiment)
The first embodiment relates to a fluororesin molded product. The fluororesin molded article according to the first embodiment includes a first part containing a conductive filler and a tetrafluoroethylene resin. This fluororesin molded product further includes a second part made of tetrafluoroethylene resin adjacent to the first part.

Since the fluororesin molded product contains a conductive filler in the first part, it is less likely to be charged as compared with a molded product made of a single tetrafluoroethylene resin, that is, a molded product made of virgin PTFE alone. Therefore, impurities such as dust, dust, and dust in the air are unlikely to adhere to the fluororesin molded product. That is, it can be said that the first part shows the dust resistance performance. The second part does not contain fillers that can be impurities in a clean environment. In other words, the second part can be said to be a non-polluting member. Therefore, the fluororesin molded product can be suitably used for applications that require a high degree of cleanliness.

The conductive filler that can be contained in the first part is a group consisting of, for example, graphite, graphene, carbon nanotubes, carbon nanofibers, potassium titanate, metal oxide, silver powder, copper powder, iron powder, and aluminum powder. It can include one or more selected from. The content of the conductive filler in the first part can be, for example, 3% by mass or more and 5% by mass or less. The content of the conductive filler referred to here indicates the mass ratio to the total mass of the first part.

The fluororesin molded article may have, for example, a vessel structure. Specifically, a container structure having a flat plate portion and a frame-shaped wall portion can be mentioned. In the container structure of one example, the frame-shaped wall portion extends in a direction intersecting the main surface direction of the flat plate portion. The first portion may be exposed at the outer main surface of the flat plate portion and the outer peripheral surface of the frame-shaped wall portion. The second portion is exposed on the inner main surface of the flat plate portion and the inner peripheral surface of the frame-shaped wall portion. That is, the first part is arranged on the outside of the container, and the second part is arranged on the inside of the container.

In the fluororesin molded product having the above container structure, impurities such as dust are unlikely to adhere due to the dust resistance of the first part on the outside. On the other hand, since the inner second part does not contain additives such as a filler, the inside of the container is not contaminated by the filler. Therefore, the fluororesin molded product can be suitably used for applications that require a high degree of cleanliness.

The fluororesin molded product may be, for example, a container having a two-layer laminated structure in which the first part is composed of the first container and the second part is composed of the second container. The first container of one example has a frame-shaped first wall portion extending in a direction intersecting the direction of the first main surface of the first flat plate portion and the first flat plate portion. The second container of the example has a frame-shaped second wall portion extending in a direction intersecting the second main surface direction of the second flat plate portion and the second flat plate portion. The inner main surface of the first flat plate portion and the outer main surface of the second flat plate portion are in close contact with each other. The inner peripheral surface of the first wall portion and the outer peripheral surface of the second wall portion are in close contact with each other. The first main surface direction and the second main surface direction can be parallel to each other. That is, the first part of the container structure and the second part of the container structure overlap each other, and the first part and the second part are arranged on the outside and the inside of the container, respectively.

In addition, the fluororesin molded product may have, for example, a sheet-like structure. The first part may be located on one main surface of the sheet and the second part may be located on the other main surface behind it. As a specific example, a laminated body in which the first part of the sheet shape and the second part of the sheet shape are laminated can be mentioned.

It is desirable that the total thickness is 5 mm or more at each part of the fluororesin molded product. Having a sufficient thickness can maintain mechanical strength. In the container structure, it is desirable that the plate thickness of the flat plate portion intersecting the main surface direction is 5 mm or more and the wall thickness of the frame-shaped wall portion is 5 mm or more. In the case of a container having a two-layer laminated structure, the sum of the thickness of the first flat plate portion in the direction intersecting the first main surface direction and the plate thickness of the second flat plate portion in the direction intersecting the second main surface direction. It is desirable that the thickness of the first wall portion is 5 mm or more, and the total thickness of the wall thickness of the first wall portion and the wall thickness of the second wall portion is 5 mm or more. In the sheet-like structure, it is desirable that the thickness in the direction intersecting the main surface of the sheet is 5 mm or more. The thickness referred to here may be the thickness of the first portion and the second portion in the stacking direction. The total thickness of each portion of the fluororesin molded product can be, for example, 20 mm or less. When the total thickness is 20 mm or less, the increase in weight and cost can be suppressed.

It is desirable that the thickness of the first part of each part of the fluororesin molded product is 3 mm or more. Dust resistance can be ensured by making the first part thicker. In the above container structure, the plate thickness of the first portion in the flat plate portion in the direction intersecting the main surface direction is 3 mm or more, and the wall thickness of the first portion in the frame-shaped wall portion is 3 mm or more. Is desirable. In the case of a container having a two-layer laminated structure, it is desirable that the thickness of the first flat plate portion in the direction intersecting the direction of the first main surface is 3 mm or more and the wall thickness of the first wall portion is 3 mm or more. .. In the sheet-like structure, it is desirable that the thickness of the first portion in the direction intersecting the main surface of the sheet is 3 mm or more. The thickness referred to here may be the thickness of the first portion and the second portion in the stacking direction. The thickness of the first portion of each portion of the fluororesin molded product can be, for example, 15 mm or less.

It is desirable that the thickness of the second part is 2 mm or more at each part of the fluororesin molded product. By making the second part thicker, contamination by the filler can be reduced. In the above container structure, the plate thickness of the second part in the flat plate portion in the direction intersecting the main surface direction is 2 mm or more, and the wall thickness of the second part in the frame-shaped wall portion is 2 mm or more. Is desirable. In the case of a container having a two-layer laminated structure, it is desirable that the thickness of the second flat plate portion in the direction intersecting the direction of the second main surface is 2 mm or more and the wall thickness of the second wall portion is 2 mm or more. .. In the sheet-like structure, it is desirable that the thickness of the second portion in the direction intersecting the main surface of the sheet is 2 mm or more. The thickness referred to here may be the thickness of the first portion and the second portion in the stacking direction. The thickness of the second portion at each portion of the fluororesin molded product can be, for example, 15 mm or less.

Specific applications of fluororesin products include, for example, cups for single-wafer semiconductor cleaning equipment. As a specific form of the fluororesin product, a mode as a cup used in a single-wafer cleaning device will be described with reference to FIGS. 1 to 4.

FIG. 1 is a plan view schematically showing an example of a fluororesin molded product according to an embodiment. FIG. 2 is a cross-sectional view of the fluororesin molded product shown in FIG. 1 cut along the line II-II'. FIG. 3 is a schematic cross-sectional view showing the use of the fluororesin molded product of the example shown in FIG. FIG. 4 is a schematic cross-sectional view showing another example of the fluororesin molded product according to the embodiment.

The cup 1 shown in FIGS. 1 and 2 includes a first cup 10 composed of a first disk portion 11 and a first wall portion 12, and a second cup 20 composed of a second disk portion 21 and a second wall portion 22. The first cup 10 is composed of a conductive filler and a tetrafluoroethylene resin. The second cup 20 is made of a tetrafluoroethylene resin. The second cup 20 is free of fillers and other additives. That is, in the fluororesin molded product having this cup structure, the first cup 10 corresponds to the first part, and the second cup 20 corresponds to the second part.

The first wall portion 12 has the shape of an annular frame extending in a direction intersecting the direction of the first main surface of the first disk portion 11. The second wall portion 22 has the shape of an annular frame extending in a direction intersecting the direction of the second main surface of the second disk portion 21. The position where the first main surface direction of the first disk portion 11 and the extending direction of the first wall portion 12 intersect may be along the outer peripheral edge of the first disk portion 11. Similarly, the position where the second main surface direction of the second disk portion 21 and the extending direction of the second wall portion 22 intersect may be along the outer peripheral edge of the second disk portion 21.

The size of the second cup 20 is smaller than the size of the first cup 10, and the second cup 20 is housed inside the first cup 10. The first disk portion 11 and the second disk portion 21 are laminated in a direction intersecting each plane direction to form a disk portion having a two-layer structure. The first wall portion 12 and the second wall portion 22 are laminated to form the annular wall portion having a two-layer structure so that the second wall portion 22 is provided along the inner wall of the first wall portion 12. .. That is, the fluororesin molded product of the illustrated example is a cup 1 having a two-layer structure in which the first cup 10 and the second cup 20 overlap.

The planar contact surface 4 shown in FIG. 2 represents a portion where the inner surface of the first disk portion 11 and the outer surface of the second disk portion 21 are in close contact with each other. The annular contact surface 7 represents a portion where the inner peripheral surface of the first wall portion 12 and the outer peripheral surface of the second wall portion 22 are in close contact with each other. There is no gap between the first cup 10 and the second cup 20, and the first cup 10 and the second cup 20 are integrated with the planar contact surface 4 and the annular contact surface 7 as boundaries. The diameter of the inner circumference of the annulus formed by the first wall portion 12 and the diameter of the outer circumference of the annulus formed by the second wall portion 22 can be equal.

The first disk portion 11 and the second disk portion 21 have a first through hole 13 and a second through hole 23, respectively. The first through hole 13 penetrates the first disk portion 11 in a direction intersecting the first main surface. The second through hole 23 penetrates the second disk portion 21 in the direction intersecting the second main surface. The first through hole 13 and the second through hole 23 are connected, and the through hole 33 composed of the connected first through hole 13 and the second through hole 23 penetrates the disk portion of the two-layer structure in the stacking direction. are doing.

In the cup 1, the first portion composed of the first cup 10 is located outside the cup-shaped container structure, and the second portion composed of the second cup 20 is located inside the cup-shaped container structure. Therefore, the first portion containing the conductive filler is exposed on the outer panel surface 2 of the cup 1 and the outer peripheral surface 5 of the annular wall portion. Then, the inner surface 3 of the cup 1 and the inner peripheral surface 6 of the annular wall portion expose the second portion made of additive-free tetrafluoroethylene resin.

An example of the use of the cup 1 will be described with reference to FIG. Specifically, the use of the cup 1 in the cleaning device will be described.

The cleaning device shown in FIG. 3 includes, for example, a jig 40 and a cup 1. The cleaning device may further include a cleaning liquid supply nozzle (not shown). The cleaning liquid supply nozzle can supply a chemical solution for cleaning the object to be cleaned. The cup 1 can be, for example, the cup 1 described with reference to FIGS. 1 and 2.

The jig 40 may include a support portion 41 extending along the rotation shaft 43 and a fixing surface 42 capable of fixing the object to be cleaned 99 and rotating together with the support portion 41. The support portion 41 can rotate around the rotation shaft 43, for example. The support portion 41 rotates at a rotation speed of 3000 rpm or less, for example. The shape of the support portion 41 may have, for example, an axisymmetric shape about the rotation shaft 43. The axisymmetric shape means a shape in which the shape does not change in the circumferential direction around the axis, but the shape changes depending only on the distance from the central axis. Examples of the shape of the support portion 41 include a columnar shape such as a cylinder or a prism, and a frustum shape.

The jig 40 shown in FIG. 3 includes a turntable 44. The turntable 44 includes a fixing surface 42 capable of fixing the object to be cleaned 99. The jig 40 does not have to include the turntable 44. In this case, the support portion 41 includes a fixed surface 42.

When the jig 40 includes the turntable 44, the turntable 44 is connected to the end portion of the support portion 41 in the rotation axis direction. Therefore, the turntable 44 can rotate together with the support 41. The shape of the turntable 44 may be an axisymmetric shape with the rotation shaft 43 as the axis, similarly to the shape of the support portion 41.

In FIG. 3, as an example, a case where both the support portion 41 and the turntable 44 have a cylindrical shape is depicted. The turntable 44 has two circular bottom surfaces. Of these two bottom surfaces, one bottom surface is connected to the support portion 41. The other bottom surface is a fixed surface 42.

The fixed surface 42 can fix the object to be cleaned 99 by, for example, vacuum suction. The fixed surface 42 preferably intersects the rotating shaft 43 perpendicularly. In this case, when the object to be cleaned 99 is cleaned while rotating the jig 40 around the rotating shaft 43, the chemical solution dropped on the object to be cleaned 99 tends to spread uniformly on the main surface of the object to be cleaned 99. .. As a result, the object to be cleaned 99 can be uniformly washed.

The object to be cleaned 99 is, for example, a semiconductor wafer having a circular main surface. The object to be cleaned 99 is not particularly limited as long as it can be fixed to the fixing surface 42.

The cup 1 is arranged at a position separated from the jig 40. The cup 1 is a cup having an annular wall portion surrounding the jig 40. The annular wall portion of the cup 1 includes the first wall portion 12 of the first cup 10 and the second wall portion 22 of the second cup 20 described above. The cup 1 further includes a disk portion including the first disk portion 11 and the second disk portion 21 described above. The main surface of the disk portion on the inner surface side of the cup 1, that is, the inner disk surface 3, which is also the main surface of the second disk portion 21, faces the fixed surface 42. The disk portion may be omitted.

The disk portion includes a through hole 33 penetrating from one main surface to the other main surface. The through hole 33 is used, for example, to supply a chemical solution onto the object to be cleaned 99.

Of the cup 1, the inner plate surface 3 and the inner peripheral surface 6 facing the jig 40 and the object to be cleaned 99 correspond to the inner surface of the second cup 20 which is the second part made of virgin PTFE. Therefore, even if the chemical solution bounces from the inner surface of the cup 1 to the object to be cleaned 99 during cleaning, there is no concern that the filler remains as an impurity. At the same time, the first cup 10, which is the first part containing the conductive filler corresponding to the outer portion of the cup 1, exhibits dust resistance, and the adhesion of dust and dust such as dust to the cup 1 is reduced. There is. Therefore, the impurity contamination of the object to be cleaned 99 can be reduced.

The shape of the cup 1 is not limited to that shown in FIGS. 1 to 3. For example, an angular gradient may be provided on the inner wall of the cup 1. Alternatively, the surface roughness may be increased by blasting the inner wall of the cup 1. By these means, the rebound of the chemical solution to the object to be cleaned can be reduced. Therefore, contamination by impurities other than the filler of the material of the cup 1 can be reduced, and impurity contamination in cleaning can be comprehensively reduced. The molded product of the example shown in FIG. 4 is a modified example in which the inner wall of the cup 1 is provided with an angular gradient.

In the cup 1 shown in FIG. 4, the first cup 10 further includes a first gradient portion 14 connecting between the first disk portion 11 and the first wall portion 12. The second cup 20 further includes a second gradient portion 24 that connects between the second disk portion 21 and the second wall portion 22. The outer slope surface 8 is formed by the first slope portion 14, and the inner slope surface 9 is formed by the second slope portion 24. The first gradient portion 14 may be omitted. By appropriately setting the inclination of the inner slope surface 9, the chemical solution scattered from the object to be cleaned can be repelled in the direction of gravity when it hits the inner slope surface 9. As a result, the amount of the chemical solution that bounces off the object to be cleaned can be reduced.

By blasting at least a part of the inner wall of the cup 1 to increase the surface roughness, it is possible to reduce the rebound of the chemical solution to the object to be cleaned for the following reasons. When the chemical solution hits a surface having a high surface roughness, the chemical solution is unlikely to bounce off at a reflection angle corresponding to the incident angle of the chemical solution. For example, the chemical solution that hits the blasted inner wall splits into a plurality of small droplets, and each droplet bounces off at various angles. As a result, the amount of the chemical solution that bounces off the object to be cleaned can be reduced.

(Second embodiment)
The second embodiment relates to the method for producing a fluororesin molded product according to the first embodiment.

One example of the manufacturing method is, for example, a step of filling the lower part of the tubular outer mold with a first raw material powder containing a conductive filler and ethylene tetrafluoride resin particles, and a step of filling the lower part of the outer mold. A step of placing a frame-shaped inner mold on the first raw material powder, a step of further filling the first raw material powder between the side surface of the outer mold and the side surface of the inner mold, and an inner mold. The process of filling the inside of the second raw material powder composed of tetrafluoroethylene resin particles, the process of removing the inner mold, and the press molding of the first raw material powder and the second raw material powder filled in the outer mold. This includes a step of obtaining an unprocessed molded product by obtaining a preformed product and firing it, and a step of performing a cutting process on the unprocessed molded product.

The first raw material powder contains a conductive filler and tetrafluoroethylene resin particles. As the conductive filler, a conductive filler that can be contained in the first part described in the first embodiment can be used. The content of the conductive filler in the first raw material powder can be, for example, 3% by mass or more and 5% by mass or less. The content of the conductive filler referred to here indicates the mass ratio to the total mass of the first raw material powder. A mixed material in which a conductive filler is mixed with tetrafluoroethylene resin particles may be used as the first raw material powder. Alternatively, composite particles of the tetrafluoroethylene resin and the conductive filler may be obtained by granulation, and the composite particles may be used as the first raw material powder.

The second raw material powder is composed of tetrafluoroethylene resin particles. That is, the second raw material powder is a virgin PTFE powder containing only particles of tetrafluoroethylene resin. The second raw material powder does not contain additives.

For the tetrafluoroethylene resin particles, for example, PTFE molding powder can be used. Here, the molding powder means a raw material powder obtained by suspension polymerization. The molding powder is once crushed to a size of several tens of μm to several hundreds of μm, and then subjected to treatments such as granulation {pelletizing}, finecutting, and presintering depending on the molding application. Is given. It is also called granular resin.

The particle size of the tetrafluoroethylene resin particles used in the first raw material powder and the second raw material powder can be, for example, 200 μm or more and 500 μm or less. The particle size of the tetrafluoroethylene resin particles contained in the first raw material powder and the particle size of the tetrafluoroethylene resin particles used in the second raw material powder may be the same or different. Good. It is desirable that the particle size of the tetrafluoroethylene resin particles is the same between the first raw material powder and the second raw material powder.

A specific example of the manufacturing method will be described with reference to FIGS. 5-14.

5-FIG. 7, FIG. 9, FIG. 11, and FIG. 12 are schematic cross-sectional views showing one step in the method for producing a fluororesin molded product according to the embodiment, respectively. FIG. 8 is a cross-sectional view taken along the line VIII-VIII'shown in FIG. FIG. 10 is a cross-sectional view cut along the X-X'line shown in FIG. FIG. 13 is a schematic cross-sectional view showing an unprocessed molded product obtained when the fluororesin molded product according to the embodiment is manufactured. FIG. 14 is a schematic cross-sectional view showing the cutting process of the unprocessed molded product shown in FIG.

FIG. 5 shows a step of filling the lower part of the outer mold with the first raw material powder containing the conductive filler and the tetrafluoroethylene resin particles. As shown in FIG. 5, the frame-shaped outer mold 52 is placed on the support plate 51. The outer mold 52 can be, for example, a metal cylinder. The support plate 51 can be, for example, a metal plate. The lower part inside the outer mold 52 is filled with the first raw material powder 61 to a desired height. Here, it is desirable to flatten the surface of the filled first raw material powder 61. The smaller the particle size of the first raw material powder 61, the easier it is to fill it flat.

FIG. 6 shows a step of placing the frame-shaped inner mold on the first raw material powder filled in the lower part of the outer mold. As shown in FIG. 6, the frame-shaped inner mold 53 is placed on the first raw material powder 61 filled in the outer mold 52. The inner mold 53 can be, for example, a metal cylinder. In order to stabilize the inner mold 53 so that it does not fall over, the lower portion of the inner mold 53 may be partially inserted into the first raw material powder 61.

7 and 8 show a step of further filling the first raw material powder between the side surface of the outer mold and the side surface of the inner mold. In the space above the first raw material powder 61a filled in the lower part of the outer mold 52, the first raw material powder 61b is added to the portion sandwiched between the side surface of the outer mold 52 and the side surface of the inner mold 53. Is filled to the desired height. The inside of the inner mold 53 is not filled with the additional first raw material powder 61b. It is desirable that the first raw material powder 61a filled in the lower portion and the additional first raw material powder 61b filled between the outer mold 52 and the inner mold 53 are the same. Hereinafter, the first raw material powder 61a and the additional first raw material powder 61b are not distinguished and are simply referred to as "first raw material powder 61".

9 and 10 show a step of filling the inner mold with a second raw material powder composed of additive-free tetrafluoroethylene resin particles. The inside surrounded by the side surface of the inner mold 53 is filled with the second raw material powder 62 composed of virgin PTFE particles to a desired height. For example, the height at which the first raw material powder 61 is filled between the outer mold 52 and the inner mold 53 and the height at which the second raw material powder 62 is filled inside the inner mold 53 can be the same. The second raw material powder 62 is stacked on a part of the first raw material powder 61.

11 and 12 are unprocessed by performing press molding on the first raw material powder and the second raw material powder filled in the outer mold and the process of removing the inner mold to obtain a preformed product and firing. The process of obtaining a molded product is shown. Even if the inner mold 53 that partitions the space is removed as shown in FIG. 11, the respective raw material powders maintain approximately the same distribution before and after the inner mold 53 is removed.

After removing the inner die 53, the press plate 54 is placed on each of the raw material powders in the outer die 52. The first raw material powder 61 and the second raw material powder 62 are pressed with a predetermined pressure using the press machine 54. As shown in FIG. 12, even in the preformed product after pressurization, the second raw material powder 62 maintains the distribution in the upper part in the center, and the first raw material powder 61 is distributed in the rest.

The obtained preformed product is fired to obtain an unprocessed molded product. The firing temperature of the preformed product is not particularly limited. For example, the uncalcined polymer of PTFE is calcined at a temperature of 340 ° C. or higher. The preferred firing temperature is 360 ° C. or higher and 380 ° C. or lower.

Since both the first raw material powder 61 and the second raw material powder 62 are mainly composed of tetrafluoroethylene resin particles, they have high affinity with each other. Therefore, by firing the preformed product, the first raw material powder 61 and the second raw material powder 62 are melted to obtain an integrated unprocessed molded product.

13 and 14 show a process of cutting an unprocessed molded product. The unprocessed molded article 70 obtained by the premolded article includes a first part 71 and a second part 72. Part 1 71 contains a conductive filler and a tetrafluoroethylene resin. That is, the first part 71 is made of a tetrafluoroethylene resin containing a conductive filler. Part 2 72 is made of an additive-free tetrafluoroethylene resin. The unprocessed molded product 70 can be machined to obtain a fluoroethylene resin molded product having a desired shape. For example, as shown by the broken line 73 shown in FIG. 14, the molded product in the shape of the cup 1 shown in FIG. 1 can be carved out.

In the above method, an integrally molded product obtained by filling and firing the first raw material powder, which is the raw material of the first part, and the second raw material powder, which is the raw material of the second part, together in the powder state. Since it is integrally molded, it is not necessary to weld and connect the separately manufactured first and second parts. In addition, there is no distortion that can occur when individually manufactured members are welded together.

The method for producing the fluororesin molded product according to the first embodiment is not limited to the above example. For example, when manufacturing a cup for a semiconductor cleaning device in which the disk portion is omitted, another manufacturing method is adopted in which the step of filling the outer mold with the first raw material powder before mounting the inner mold is omitted. You may.

In another example of the manufacturing method according to the embodiment, for example, the first raw material powder is placed between the side surface of the tubular outer mold and the side surface of the frame-shaped inner mold placed in the outer mold. The step of filling, the step of filling the inside of the inner mold with the second raw material powder, the step of removing the inner mold, and the step of pressing the first raw material powder and the second raw material powder filled in the outer mold. It includes a step of obtaining an unprocessed molded product by performing molding to obtain a preformed product and firing it, and a step of performing a cutting process on the unprocessed molded product.

For example, the inner mold can be placed directly on the support plate before the first raw material powder is filled in the outer mold. The first raw material powder is filled between the outer mold and the inner mold, the second raw material powder is filled inside the inner mold, and then press molding and firing are performed, whereby, for example, the second part is formed. It is possible to obtain a cylindrical unprocessed molded product having a core portion and a first portion located outside the core portion. By cutting into a desired shape, a fluororesin molded product can be obtained.

According to the embodiment described above, a fluororesin molding comprising a first part containing a conductive filler and a tetrafluoroethylene resin and a second part composed of a tetrafluoroethylene resin and adjacent to the first part. Goods are offered. This fluororesin molded product can reduce impurity contamination.

The present invention is not limited to the above embodiment, and can be variously modified at the implementation stage without departing from the gist thereof. In addition, each embodiment may be carried out in combination as appropriate, and in that case, the combined effect can be obtained. Further, the above-described embodiment includes various inventions, and various inventions can be extracted by a combination selected from a plurality of disclosed constituent requirements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, if the problem can be solved and the effect is obtained, the configuration in which the constituent requirements are deleted can be extracted as an invention.

1 ... Cup, 2 ... Outer board surface, 3 ... Inner board surface, 4 ... Flat contact surface, 5 ... Outer surface surface, 6 ... Inner peripheral surface, 7 ... Circular contact surface, 8 ... Outer slope surface, 9 ... Inner slope surface 10, ... 1st cup, 11 ... 1st disk part, 12 ... 1st wall part, 13 ... 1st through hole, 14 ... 1st gradient part, 20 ... 2nd cup, 21 ... 2nd disk part, 22 ... 2nd wall part, 23 ... 2nd through hole, 24 ... 2nd gradient part, 33 ... through hole, 40 ... jig, 41 ... support part, 42 ... fixed surface, 43 ... rotating shaft, 44 ... turntable, 51 ... Support plate, 52 ... Outer mold, 53 ... Inner mold, 54 ... Press machine, 61 ... First raw material powder, 61a ... First raw material powder, 61b ... First raw material powder, 62 ... Second raw material powder, 70 ... Unprocessed molded product, 71 ... Part 1, 72 ... Part 2, 73 ... Broken line, 99 ... Object to be cleaned.

Claims (8)

Part 1 containing the conductive filler and the tetrafluoroethylene resin,
A fluororesin molded product containing the first part and a second part made of tetrafluoroethylene resin adjacent to the first part. The conductive filler comprises one or more selected from the group consisting of graphite, graphene, carbon nanotubes, carbon nanofibers, potassium titanate, metal oxides, silver powder, copper powder, iron powder, and aluminum powder. The fluororesin molded product according to claim 1. The fluororesin molded product according to claim 1 or 2, wherein the content of the conductive filler in the first part is 3% by mass or more and 5% by mass or less. Flat plate and
It has a container structure having a frame-shaped wall portion extending in a direction intersecting the main surface direction of the flat plate portion.
The first portion is exposed on the outer main surface of the flat plate portion and the outer peripheral surface of the frame-shaped wall portion, and the second portion is exposed on the inner main surface of the flat plate portion and the inner peripheral surface of the frame-shaped wall portion. The fluororesin molded product according to any one of claims 1 to 3, wherein the portion is exposed. The fluororesin molded product according to claim 4, wherein the plate thickness of the flat plate portion in a direction intersecting the main surface direction is 5 mm or more, and the wall thickness of the frame-shaped wall portion is 5 mm or more. The plate thickness of the first portion of the flat plate portion in the direction intersecting the main surface direction is 3 mm or more, and the plate thickness of the second portion of the flat plate portion in the direction intersecting the main surface direction is 2 mm. The fifth aspect of the present invention, wherein the wall thickness of the first portion of the frame-shaped wall portion is 3 mm or more, and the wall thickness of the second portion of the frame-shaped wall portion is 2 mm or more. Fluororesin molded product. The first portion comprises a first container having a first flat plate portion and a frame-shaped first wall portion extending in a direction intersecting the first main surface direction of the first flat plate portion.
The second portion comprises a second container having a second flat plate portion and a frame-shaped second wall portion extending in a direction intersecting the second main surface direction of the second flat plate portion.
The inner main surface of the first flat plate portion and the outer main surface of the second flat plate portion are in close contact with each other, and the inner peripheral surface of the first wall portion and the outer peripheral surface of the second wall portion are in close contact with each other. , The fluororesin molded product according to any one of claims 1 to 3. The plate thickness of the first flat plate portion in the direction intersecting the first main surface direction is 3 mm or more, the wall thickness of the first wall portion is 3 mm or more, and the direction intersecting the second main surface direction. The fluororesin molded product according to claim 7, wherein the thickness of the second flat plate portion is 2 mm or more, and the wall thickness of the second wall portion is 2 mm or more.

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