JPWO2020009169A1 - Pellicle frame - Google Patents

Abstract

The pellicle frame (1) in one aspect of the present disclosure has a rectangular shape in a plan view, and the outer peripheral surface (13) of the pellicle frame (1) is provided with one or a plurality of recesses (25), and one of the same. Alternatively, the plurality of recesses (25) are provided on one or a plurality of side portions out of the four side portions. The one or a plurality of recesses (25) are provided with through holes (27) that penetrate the side portion provided with the recess (25) and open to the inside and the inner peripheral surface (11) of the recess (25). ing. Of the one or a plurality of recesses (25), at least one recess (25) is provided with a plurality of through holes (27). Further, in the recess (25) provided with at least one through hole (27), the ventilation area S1 which is the area of the opening end on the outer peripheral surface (13) side of the recess (25) is the through hole (27). It is larger than the minimum cross-sectional area S2, which is the minimum cross-sectional area of the gas flow path to be formed.

Description

Cross-reference of related applications

This international application claims priority based on Japanese Patent Application No. 2018-127636 filed with the Japan Patent Office on July 4, 2018, and Japanese Patent Application No. 2018-127636 The entire contents are incorporated in this international application by reference.

The present disclosure relates to a pellicle frame.

In semiconductor manufacturing, a photomask is used in an exposure process for forming a wiring pattern on a semiconductor wafer, and if foreign matter (particles or the like) adheres to the photomask, a defect in the wiring pattern occurs.

As a countermeasure, that is, in order to prevent dust, a pellicle on which a transparent thin film (pellicle film) covering the surface of the photomask is stretched is used.

Further, in order to arrange the pellicle film at a predetermined distance from the photomask, a rectangular frame called a pellicle frame is used. As a member constituting this frame, a member having a small diameter such as a prism having a length of 3 mm and a width of 2 mm is used.

Further, the pellicle frame is provided with a small-diameter through hole (that is, a ventilation hole) for communicating the inside and the outside of the pellicle, and dust or the like invades the inside of the pellicle at the opening end outside the ventilation hole. Filters are placed to prevent this from happening.

Further, in recent years, the wiring pattern and the like have been miniaturized, and along with this, the wavelength of the exposed light beam has been shortened. For example, EUV exposure using EUV (Extreme Ultra Violet) light having a main wavelength of 13.5 nm is being studied.

In this EUV exposure, the pellicle is attached to the photomask in the atmosphere and used under vacuum in the exposure apparatus, so that vacuuming is performed in the exposure apparatus or the like. Further, in the process after evacuation, the air is released to the atmosphere (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-191902

By the way, conventionally, since the filter is arranged so as to directly cover the open end of the ventilation hole, there is a problem that it is not easy to evacuate or release to the atmosphere in a short time. That is, when the above-mentioned evacuation or the like is performed, air can pass through the filter only in the region of the cross-sectional integration of the ventilation holes. And since the pressure loss of the filter is much larger than that of the ventilation holes, it is difficult for air to pass through the filter as compared with the ventilation holes. Therefore, it is not easy to evacuate in a short time.

As a countermeasure against this, Patent Document 1 discloses a technique in which a member communicating with a vent is provided so as to project inside or outside the pellicle frame, and a filter is arranged in the overhanging portion in parallel with the pellicle film. There is.

However, this conventional technique has a problem that the internal space of the pellicle becomes small and the exposure range becomes small. Alternatively, there is a problem that the external dimensions of the pellicle become large and the pellicle becomes large. Moreover, since the structure of the pellicle frame becomes very complicated, it is not easy to provide such a structure in the pellicle frame which is a frame body having a small diameter.

In addition to this measure, it is conceivable to provide a large number of ventilation holes in the pellicle frame, but in this case, the strength of the pellicle frame may decrease depending on the material of the pellicle frame.

In one aspect of the present disclosure, it is desirable to provide a pellicle frame that can be quickly evacuated and released to the atmosphere, has a simple structure, and has sufficient strength.

(1) The pellicle frame in one aspect of the present disclosure has a rectangular shape in a plan view, includes four side portions corresponding to each side of the rectangular shape, and has a first surface provided on both sides in the thickness direction and a first surface. It relates to a pellicle frame including a second surface and an inner peripheral surface and an outer peripheral surface connected to the first surface and the second surface.

The pellicle frame is provided with one or a plurality of recesses on its outer peripheral surface, and one or a plurality of recesses are provided on one or a plurality of side portions among the four side portions. The one or a plurality of recesses are provided with through holes that penetrate the side portion provided with the recess and open to the inside and the inner peripheral surface of the recess. Further, at least one of the one or a plurality of recesses is provided with a plurality of through holes.

Moreover, in this pellicle frame, in a recess provided with at least one through hole, the ventilation area (S1), which is the area of the opening end on the outer peripheral surface side of the recess, is the minimum disconnection of the gas flow path formed by the through hole. It is larger than the minimum cross-sectional area (S2), which is the area.

This pellicle frame is used as a frame body constituting the pellicle. In this pellicle frame, for example, a pellicle film is stretched on the second surface side, and a filter is provided on the outer peripheral surface side of the recess in which the through hole (that is, the ventilation hole) is opened so that dust or the like does not enter the inside of the pellicle. (That is, the first filter) is arranged.

In particular, this pellicle frame has a ventilation area (S1) larger than the above-mentioned minimum cross-sectional area (S2). Specifically, in the pellicle frame, the area of the opening end on the outer peripheral surface side of the recess, that is, the ventilation area (S1) which is the area of the portion where the recess opens on the outer peripheral surface (that is, the area of the opening portion), and therefore the surface to the opening end. The area of the filter that covers the entire opening end (so-called effective ventilation area) is larger than the minimum cross-sectional area (S2), which is the minimum cross-sectional area of the gas flow path formed by the through hole.

Therefore, when the filter is arranged so as to cover the open end of the concave portion and the inside of the pellicle is evacuated (that is, when evacuated), the evacuation can be performed in a short time.

That is, since the pressure loss of the filter is larger than that of the through hole, when the open end of the through hole is simply covered with the filter, the air flow is regulated by the filter and the evacuation time becomes long. On the other hand, in this pellicle frame, the filter is arranged so as to cover the open end of the recess having a ventilation area (S1) larger than the minimum cross-sectional area (S2) of the through hole, that is, the area of the filter penetrates. Since it is larger than the cross-sectional area of the hole, vacuuming can be performed in a shorter time than when the open end of the through hole is directly covered with a filter.

The same applies to the case of releasing the atmosphere from the outside of the pellicle to the inside of the pellicle, and the atmosphere can be released in a short time.

Further, in this pellicle frame, the internal space of the pellicle is not reduced as in the conventional case, so that the exposure range is not reduced. Alternatively, there is no problem that the external dimensions of the pellicle become large and the pellicle becomes large.

Moreover, since the structure of the pellicle frame is not complicated as in the conventional case, the recess can be easily provided even in the pellicle frame which is a frame body having a small diameter. Further, since it is not necessary to provide a large number of ventilation holes, it is possible to suppress a decrease in the strength of the pellicle frame by providing a large number of ventilation holes.

The thickness direction is the direction in a plan view, that is, the direction from the first surface to the second surface. The minimum cross-sectional area of the gas flow path is the smallest cross-sectional area of the cross-sectional areas perpendicular to the gas flow direction (that is, the flow path direction) in the gas flow path.

(2) In the above-mentioned pellicle frame, the minimum cross-sectional area (S2) is the minimum cross-sectional area of the gas flow path formed by the through hole when there is one through hole, and when there are a plurality of through holes. Is the sum of the minimum cross-sectional areas of each gas flow path formed by each through hole.
(3) In the above-mentioned pellicle frame, the ratio (opening area) of the total area of the opening ends of all the recesses (Smm ² ) and the volume of the inner space surrounded by the inner peripheral surface of the pellicle frame (internal volume: Vmm ^3). The ratio: S / V) may be 0.002 mm ^-1 or more and 0.025 mm ^-1 or less.

This pellicle frame, the ratio (S / V) is, 0.002 mm ^-1 or 0.025 mm ^{- 1} In each case below, it is possible to perform evacuation and air released in a short time.

(4) The above-mentioned pellicle frame may be provided with a first filter that covers the open end on the outer peripheral surface side of the recess.

This pellicle frame exemplifies a pellicle frame including a filter (that is, a first filter). In the case of such a configuration, for example, when air is introduced from the outside to the inner peripheral side of the pellicle frame through a recess or a through hole, foreign matter such as dust in the air can be collected by the first filter. can.

(5) In the pellicle frame described above, an adhesive layer may be provided on at least one of the inner surface of the recess and the inner surface of the through hole.

In the case of such a configuration, since the adhesive layer is provided between the first filter and the inner peripheral surface side of the pellicle frame through the recess and the through hole, for example, foreign matter in the air can be prevented. It is easily collected by the adhesive layer. Therefore, there is an advantage that the collection efficiency of foreign matter is high.

(6) In the pellicle frame described above, the inner surface of the recess may be provided with irregularities.

In the case of such a configuration, since the air has irregularities between, for example, from the first filter to the through hole, foreign matter is likely to be collected by the irregularities of the recesses. Therefore, there is an advantage that the collection efficiency of foreign matter is improved.

(7) In the pellicle frame described above, in the first filter, a ventilation suppressing portion for suppressing the ventilation of the first filter may be provided in the facing region facing the opening of the through hole.

In such a configuration, when air reaches, for example, from the first filter to the through hole, it does not reach the through hole directly (that is, at the shortest distance) from the first filter, but the ventilation is suppressed. It reaches the through hole through the portion or avoiding the ventilation suppression portion. Therefore, there is an effect that the efficiency of collecting foreign substances in the air is improved.

For example, when the ventilation suppression part completely blocks the ventilation, the air moves avoiding the ventilation suppression part, so that the flow path becomes long, and thus it is difficult for foreign matter to directly enter the through hole. There is an advantage.

(8) In the above-mentioned pellicle frame, a second filter having higher air permeability than the first filter and covering the opening of the through hole is provided inside the recess, and the second filter has an adhesive layer around its own gas flow path. May be provided.

In the case of such a configuration, foreign matter in the air can be collected not only by the first filter but also by the second filter (particularly the adhesive layer thereof), so that there is an advantage that the collection efficiency of the foreign matter is improved. ..

(9) In the above-mentioned pellicle frame, the corners of the inner surface of the recess may be R-chamfered.

In the case of such a configuration, the air flow along the inner peripheral surface of the recess is likely to occur, so that the efficiency of collecting foreign matter is improved. Moreover, there is an advantage that the strength of the pellicle frame is improved.

(10) In the above-mentioned pellicle frame, the pellicle frame may be made of a conductive ceramic sintered body.

In the case of such a configuration, the pellicle frame can be easily machined by electric discharge machining.

(11) In the pellicle frame described above, the pellicle frame may have a Young's modulus of 300 GPa or more and a strength of 500 MPa or more.

In the case of such a configuration, since the pellicle frame has sufficient rigidity and strength, it is less likely to be deformed or damaged, which is suitable.

Here, the strength indicates the three-point bending strength at L = 30 mm defined in JIS R1601: 2008.

(12) In the pellicle frame described above, the pellicle frame may be made of a ceramic sintered body having a thermal conductivity of 15 W / mK or more.

In the case of such a configuration, since the pellicle frame has high heat transfer property, the pellicle frame can efficiently diffuse the heat generated in the pellicle film during exposure and prevent the pellicle film from being damaged by the heat.

(13) In the above-mentioned pellicle frame, the pellicle frame may be made of a ceramic sintered body having a thermal expansion coefficient of 10 ppm / ° C. or less.

In the case of such a configuration, it is possible to preferably suppress the deformation of the pellicle frame due to the temperature rise during exposure.

The coefficient of thermal expansion is the coefficient of linear thermal expansion in the temperature range of room temperature (25 ° C.) to 600 ° C.

(14) The above-mentioned pellicle frame may satisfy the following relational expression.

50 x minimum cross-sectional area (S2) ≤ ventilation area (S1)
With this configuration, evacuation and the like can be performed in a shorter time.

<The structure of the present disclosure will be described below>
As the material of the pellicle frame, a conductive or non-conductive material can be adopted. For example, as a material constituting the pellicle frame, a material containing ceramics as a main component can be adopted. The main component indicates the largest amount of components (for example,% by weight).

For example, as the conductive material, alumina / titanium carbide, alumina / titanium carbide / titanium nitride, zirconia / titanium carbide, cemented carbide, cermet and the like can be adopted. Further, a metal such as duralumin (for example, an alloy) can be adopted.

When the material constituting the pellicle frame is a conductive material, the outer shape of the pellicle frame, recesses, through holes, etc. are removed by electric discharge machining (for example, wire electric discharge machining, fine hole electric discharge machining, die-sinking electric discharge machining, etc.). It can be easily processed into a desired shape.

Further, as the non-conductive material, for example, ceramics such as alumina, silicon nitride, and zirconia can be adopted.

As the dimensions of the pellicle frame, the width and thickness of the frame portion can be, for example, in the range of 2.0 mm to 5.0 mm. As the size of the opening (central through hole), for example, a range of 120 mm to 150 mm in length and 150 mm to 120 mm in width can be adopted.

It is a perspective view which shows the pellicle frame of 1st Embodiment. 2A is a front view showing a fourth side portion of the pellicle frame of the first embodiment, FIG. 2B is a cross-sectional view showing a cross section of IIB-IIB of FIG. 2A, and FIG. 2C is a cross-sectional view showing a cross section of IIC-IIC of FIG. 2A. be. It is a perspective view which shows the pellicle of 1st Embodiment. 4A is a front view showing a fourth side portion of the pellicle of the first embodiment, FIG. 4B is a cross-sectional view showing an IVB-IVB cross section of FIG. 4A, and FIG. 4C is a cross-sectional view showing an IVC-IVC cross section of FIG. 4A. .. It is a process drawing which shows the manufacturing method of the pellicle frame of 1st Embodiment. It is sectional drawing which shows the cross section (cross section parallel to the XY plane) of the main part including the recess and the ventilation hole of the pellicle frame of 2nd Embodiment. FIG. 7A is a plan view showing a main part including a recess and a ventilation hole of the pellicle frame of the third embodiment, and FIG. 7B is a cross-sectional view showing a cross section of VIIB-VIIB of FIG. 7A. FIG. 8A is a plan view showing a concave portion of the pellicle frame of the modified example 1 and a main part including a ventilation hole, and FIG. 8B is a plan view showing a main part including the concave portion and the vent hole of the pellicle frame of the modified example 2. 9A is a plan view showing a main part including a recess and a ventilation hole of the pellicle frame of the fourth embodiment, and FIG. 9B is a cross-sectional view showing a cross section of IXB-IXB of FIG. 9A. It is sectional drawing which shows the cross section (cross section parallel to the XY plane) of the main part including the recess and the ventilation hole of the pellicle frame of 5th Embodiment. 11A is a plan view showing a main part including a recess and a ventilation hole of the pellicle frame of the sixth embodiment, and FIG. 11B is a cross-sectional view showing a cross section of XIB-XIB of FIG. 11A.

1, 31, 41, 51, 61, 71, 81, 91 ... Pellicle frame 5 ... First filter 11 ... Inner peripheral surface 13 ... Outer peripheral surface 15 ... Second surface 17 ... First surface 21 ... Side 25 ... Recessed 27 ... Vent hole 27a ... Opening 33 ... Adhesive material layer 73 ... Ventilation suppression part 83 ... Second filter

Hereinafter, embodiments of the pellicle frame of the present disclosure will be described with reference to the drawings.

[1. First Embodiment]
[1-1. overall structure]
First, the overall configuration of the pellicle frame of the first embodiment will be described.

As schematically shown in FIGS. 1 to 4, the pellicle frame 1 is a member to which a pellicle film 3 (see FIG. 4A) is stretched on one side of the pellicle frame 1 (above FIG. 4A). The pellicle frame 1 is made of a material containing ceramic as a main component (for example, conductive ceramics containing alumina as a main component and titanium carbide as a main component). That is, the pellicle frame 1 is, for example, a conductive ceramic sintered body containing alumina as a main component.

Note that FIGS. 1 and 2 show the pellicle frame 1 itself, and FIGS. 3 and 4 show a pellicle 7 having a pellicle film 3 and a filter 5 described later in the pellicle frame 1.

Further, in the following, among all the surfaces of the pellicle frame 1, the inner surface surrounded by the pellicle frame 1 itself is referred to as an inner peripheral surface 11, and the outer surface opposite to the inner surface is referred to as an outer peripheral surface 13. Of the surfaces connected to the inner peripheral surface 11 and the outer peripheral surface 13, the side on which the pellicle film 3 is stretched is the upper surface (for example, the second surface) 15, and the opposite surface is a photomask (not shown). It is called the lower surface (for example, the first surface) 17 to be attached.

As shown in FIG. 1, in the orthogonal X-axis, Y-axis, and Z-axis coordinate systems, the pellicle frame 1 is a rectangular frame (that is, an annular member) having a rectangular shape in a plan view from the Z direction. ), And has a rectangular central through hole 19 in the center in a plan view.

That is, the pellicle frame 1 is composed of long frame portions arranged on the same plane in the four directions of up, down, left, and right in a plan view. Specifically, the pellicle frame 1 is composed of a first side portion 21a and a second side portion 21b arranged parallel to the X axis, and a third side portion 21c and a fourth side portion 21d arranged parallel to the Y axis. It is configured. The first side portion 21a and the second side portion 21b are shorter in size than the third side portion 21c and the fourth side portion 21d. The first to fourth side portions 21a to 21d are collectively referred to as side portions 21.

The outer dimensions of the pellicle frame 1 are, for example, 149 mm in the vertical direction (Y direction) × 120 mm in the horizontal direction (X direction) × 1.8 mm in the thickness (Z direction). Further, each side portion 21 of the pellicle frame 1 is a square pillar, and the width dimension (width dimension when viewed from the Z direction: frame width) is the same (for example, 2 mm).

Further, the pellicle frame 1 has a Young's modulus of 300 GPa or more and a strength (three-point bending strength defined by JIS R1601: 2008) of 500 MPa or more. Further, the pellicle frame 1 has a thermal conductivity of 15 W / mK or more and a thermal expansion coefficient of 10 ppm / ° C. or less in a temperature range of room temperature (25 ° C.) to 600 ° C. The flatness of the second surface 15 and the first surface 17 of the pellicle frame 1 is 10 μm or less.

Further, as shown in FIG. 1, the pellicle frame 1 has two locations (total) on the outer peripheral surface 13 side of both frame portions (that is, the third side portion 21c and the fourth side portion 21d of the long side) in the X direction. Bottomed holes 23 are formed at four places).

The bottomed hole 23 is, for example, a bottomed round hole having a diameter of 1.5 mm and a depth of 1.2 mm, and the bottom portion is arranged in a conical shape. The bottomed hole 23 is used for positioning the pellicle 7 and subsequent attachment to the photomask, and for a grip portion during transportation.

[1-2. Composition of key parts]
Next, the main part of the pellicle frame 1 of the first embodiment will be described.

As shown in FIG. 1, groove-shaped recesses 25 are formed on the outer peripheral surfaces 13 of all the side portions 21 of the pellicle frame 1.

Hereinafter, the recess 25 will be described by taking as an example the recess 25 provided in the fourth side portion 21d, but since the recess 25 of the first to third side portions 21a to 21c also has the same shape, the recess 25 is described. The description is omitted. Specifically, the recess 25 of the first side portion 21a and the recess 25 of the second side portion 21b have the same shape, and the recess 25 of the third side portion 21c and the fourth side portion 21d have the same shape. Further, the recess 25 of the third side portion 21c and the fourth side portion 21d has a longer dimension in the longitudinal direction than the recess 25 of the first side portion 21a and the second side portion 21b, but the other dimensions are the first side. It is the same as the portion 21a and the second side portion 21b.

In the first embodiment, recesses 25 are formed on the outer peripheral surfaces 13 of all the side portions 21 of the pellicle frame 1, but recesses are formed in at least one side portion 21 of all the side portions 21. 25 may be provided. Further, the recess 25 provided in one side portion 21 may be a plurality of recesses 25 divided into a plurality of portions. That is, a plurality of recesses 25 may be provided on one side portion 21.

As shown in FIG. 2, the recess 25 is a groove formed along the longitudinal direction (Y direction) of the fourth side portion 21d. The shape of the space in the groove is a rectangular parallelepiped.

Specifically, as shown in FIG. 2A, the dimension L1 of the recess 25 in the Y direction is, for example, 139 mm, and is provided in a range not reaching both ends of the fourth side portion 21d in the Y direction.

Since the thickness (that is, the dimension in the Z direction) W1 of the fourth side portion 21d is, for example, 1.8 mm, the dimension W2 in the Z direction of the recess 25 is shorter, for example, 1.2 mm. That is, there is a gap W3 that is room for attaching the filter 5 between the side surface 25a, which is the inner peripheral surface of the recess 25 on the second surface 15 side, and the second surface 15 of the fourth side portion 21d. Similarly, there is a gap W4 between the side surface 25b, which is the inner peripheral surface of the recess 25 on the first surface 17 side, and the first surface 17 of the fourth side portion 21d.

Here, the dimensions of both gaps W3 and W4 are the same (may be different), and in order to securely attach the filter 5, it is preferably 0.2 mm or more (for example, 0.2 mm to 0). .3 mm).

Further, as shown in FIG. 2B, the width (that is, the dimension in the X direction) D1 of the fourth side portion 21d is, for example, 2 mm, so that the dimension D2 in the depth (X direction) of the recess 25 is, for example, 20% of D1. For example, 0.5 mm in the range of ~ 50%.

Further, the fourth side portion 21d is provided with a plurality of ventilation holes 27. Specifically, the rectangular bottom portion 25c of the recess 25 of the fourth side portion 21d (the bottom portion 25c is parallel to the inner peripheral surface 11) penetrates the fourth side portion 21d in the X-axis direction and is recessed. It is provided with two ventilation holes 27 that open to the inner bottom portion 25c of the 25 and the inner peripheral surface 11 side of the pellicle frame 1. The ventilation hole 27 is a columnar through hole having a diameter of, for example, φ0.5 mm. Here, two ventilation holes 27 are provided on the fourth side portion 21d, but for example, three or more ventilation holes 27 may be provided.

Further, here, an example in which a plurality of (for example, two) ventilation holes 27 are provided in all four side portions 21 (hence, all four recesses 25) is given, but at least one recess is provided. The configuration may be such that the 25 is provided with a plurality of ventilation holes 27.

The number of ventilation holes 27 provided in one recess 25 may be two or three or more. Further, since it is sufficient that at least one recess 25 is provided with a plurality of ventilation holes 27, one ventilation hole 27 may be provided in the other recess 25.

In particular, in the first embodiment, the "ventilation area S1" is larger than the "minimum cross-sectional area S2".

Here, taking the fourth side portion 21d as an example, the ventilation area S1 is an opening end on the outer peripheral surface 13 side of the recess 25 of the fourth side portion 21d (that is, a portion that opens on the same surface as the outer peripheral surface 13). Shows the area of.
Further, the minimum cross-sectional area S2 indicates the total of the minimum cross-sectional areas of the respective vent holes 27 in the two vent holes 27 of the recess 25 of the fourth side portion 21d. Specifically, the minimum cross-sectional area S2 is obtained by obtaining the cross-sectional area perpendicular to the axial direction (that is, the cross-sectional area of the vertical surface) in each of the ventilation holes 27, and obtaining the total of the cross-sectional areas. Since the cross-sectional area of each vent hole 27 is the same in the axial direction, the minimum cross-sectional area of each vent hole 27 is the same at any position in the axial direction.

When there is one ventilation hole 27, the cross-sectional area perpendicular to the axial direction of each ventilation hole 27 is the minimum cross-sectional area S2.

Further, the cross-sectional area perpendicular to the axial direction of the vent hole 27 is, here, the flow path formed by the vent hole 27 which is a through hole (that is, the cross-sectional area of the gas flow path). That is, it is a cross-sectional area perpendicular to the direction in which the gas flows. The plane perpendicular to the axial direction of each of the ventilation holes 27 is a plane (that is, a YZ plane) parallel to the outer peripheral surface 13 of the fourth side portion 21d.

Here, the cross-sectional area perpendicular to the axial direction of each vent hole 27 is the same regardless of the cross-sectional area at any position in the axial direction, but if the cross-sectional area of each vent hole 27 differs depending on the location, The minimum cross-sectional area is obtained as the cross-sectional area of each of the ventilation holes 27, and the total is taken as the minimum cross-sectional area S2.

Specifically, the ventilation area S1 of the recess 25 of the fourth side portion 21d is L1 × W2, so that it is, for example, 139 mm × 1.2 mm = 166.8 mm ² . The minimum cross-sectional area S2 is the sum of the cross-sectional area of the two vent holes 27 in the recess 25, for example (0.25mm × 0.25mm × π) × 2 = about 0.39 mm ^2. Therefore, the recess 25 of the fourth side portion 21d satisfies the condition of "ventilation area S1> minimum cross-sectional area S2".

Further, in the recess 25 of the fourth side portion 21d, the ventilation area S1 and the minimum cross-sectional area S2 satisfy the following relational expression.

50 x minimum cross-sectional area S2 ≤ ventilation area S1 ... (A)
In this way, by setting the ventilation area S1 to 50 times or more the minimum cross-sectional area S2, vacuuming or the like can be performed in a shorter time.

Here, the recess 25 of the fourth side portion 21d is taken as an example, but the recesses 25 of the other first to third side portions 21a to 21c also have the same “ventilation area S1> minimum cross-sectional area S2”. The condition and the condition of "50 x minimum cross-sectional area S2 ≤ ventilation area S1" are satisfied.

When each of the ventilation holes 27 has the same opening diameter, the minimum cross-sectional area S2 may be obtained by multiplying the cross-sectional area of one ventilation hole 27 by the number of ventilation holes 27 as described above.

As shown in FIGS. 3 and 4, the filter (that is, the first filter) 5 is a well-known filter that prevents the inflow of foreign matter such as dust into the pellicle 7 fixed to the photomask, and prevents the inflow of foreign matter. It is made of a well-known material that is possible.

As the filter 5, a filter according to the purpose may be appropriately used.

For example, a ULPA filter (Ultra Low Penetration Air Filter) can be used. The ULPA filter is an air filter having a particle collection rate of 99.9995% or more with respect to particles having a particle size of 0.15 μm at a rated air volume and having an initial pressure loss of 245 Pa or less.

Further, as the filter 5, a HEPA filter (High Efficiency Particulate Air Filter) may be used. The HEPA filter is an air filter having a particle collection rate of 99.97% or more and an initial pressure loss of 245 Pa or less with respect to particles having a rated air volume and a particle size of 0.3 μm.

As shown in FIG. 4A, the filter 5 has a rectangular shape when viewed from the outer peripheral surface 13 side, covers all the rectangular opening ends of the concave portions 25, and covers the entire circumference of the opening ends with a predetermined width. It covers in a frame shape.

The filter 5 is attached to the outer peripheral surface 13 of the fourth side portion 21d, specifically, around the open end of the recess 25, by, for example, an adhesive. The portion of the filter 5 that covers the periphery of the open end of the recess 25 is a so-called glue allowance, and the width thereof can be, for example, in the range of 0.2 mm to 0.3 mm.

^{In the first embodiment, the total area (Smm 2} ) of the open ends of all (that is, four) recesses 25 and the volume of the inner space surrounded by the inner peripheral surface 11 of the pellicle frame 1 (Vmm ³ ). The ratio with and (opening area ratio: S / V) is 0.002 mm ^-1 or more and 0.025 mm ^-1 or less.

[1-3. Manufacturing method of pellicle frame]
Next, a method of manufacturing the pellicle frame 1 will be described. The dimensions of each part are examples.
(First step P1)
As shown in FIG. 5, first, in the first step (base material preparation step) P1, a powder (that is, base material powder) which is a raw material of the pellicle frame 1 was prepared.

Here, the powder is a substance that is the basis of the sintered body that constitutes the pellicle frame 1. After appropriately adding a sintering aid or the like to the raw material powder such as alumina or a conductive material, wet mixing is performed, and then spray drying is performed. It was prepared into granules of 50 μm to 100 μm by the method. The particle size of the raw material powder was measured by a laser diffraction / scattering method, but it may also be measured by a dynamic light scattering method or a sedimentation method.

Specifically, in the process of producing the substrate, 63% by volume of α-alumina powder having an average particle size of 0.5 μm, 10% by volume of titanium carbide having an average particle size of 1.0 μm, and 25% by volume of titanium nitride having an average particle size of 1.0 μm. the balance _{MgO: Y 2 O 3 = 1} : prepare a composite material comprising a first sintering aid.

Then, this composite material was wet-mixed, an organic binder for molding was added, and then a composite ceramic base powder of alumina, titanium carbide, and titanium nitride was prepared by a normal spray drying method. (Second step P2)
Next, in the second step (molding step) P2, this powder was molded to form the original shape of the pellicle frame 1.

Specifically, the composite ceramic base powder is molded into a frame shape having external dimensions of 182 mm in length × 147 mm in width × 6 mm in thickness and a frame width of about 5 mm by a mold pressing method, and the prototype (powder molded body) of the pellicle frame 1 is formed. Made.

Here, since the outer shape of the pellicle frame 1 shrinks by about 20 to 30% by the firing step described later, the pellicle frame 1 is formed larger than the fired pellicle frame 1 in advance. The pellicle frame 1 can have various sizes according to the size of the exposure mask in the semiconductor exposure apparatus.
(Third step P3)
Next, in the third step (baking step) P3, after molding the powder, it was fired at a predetermined temperature.

Specifically, the powder molded body was debindered, held in an inert gas at 1700 ° C. for 3 hours, and fired to obtain a dense ceramic sintered body having conductivity.

The firing temperature depends on the composition of the powder, but is generally 1500 ° C. or higher. By firing, a sintered body having a high Young's modulus and strength can be obtained.

The dimensions of this sintered body were about 151 mm in length × 122 mm in width × 5 mm in thickness and about 4 mm in frame width. There was a distortion of about 0.3 mm.
(4th step P4)
Next, in the fourth step (thickness processing step) P4, the sintered body was subjected to thickness processing (specifically, grinding processing) for adjusting the thickness thereof.

Specifically, the upper and lower surfaces (both sides in the thickness direction) of the sintered body were ground in approximately the same amount with a surface grinding machine and processed to a thickness of 2.1 mm. The flatness after surface grinding was 20 μm to 40 μm.

Here, the thickness is made uniform while leaving the grinding allowance (for example, 0.05 mm to 0.10 mm) of the precision flat surface processing (10th step P10) described later.
(Fifth step P5)
Next, in the fifth step (inner shape / outer shape processing step) P5, the inner shape / outer shape processing was performed on the sintered body after the thickness processing.

Specifically, the inner shape and outer shape of the sintered body were machined to a length of 149 mm, a width of 120 mm, and a frame width of 2 mm by wire electric discharge machining. That is, the outer peripheral surface of the sintered body is gripped by a holding jig (not shown), wire electric discharge machining is performed on the inner peripheral surface and the outer peripheral surface of the sintered body, and the dimensions for the inner shape and outer shape are intended. Processed into. At this time, the ridge portion (corner portion) may be R-processed.
(6th step P6)
Next, in the sixth step (drilling step) P6, two bottomed holes 23 were formed on the opposite long sides of the sintered body by the die-sinking electric discharge machining.

Specifically, with respect to the sintered body, a bottomed hole having a diameter of φ1.6 mm and a depth of 1.2 mm is formed in a portion of the pellicle frame 1 corresponding to the outer peripheral surface 13 of the third side portion 21c and the fourth side portion 21d. 23 was formed.
(7th step P7)
Next, in the seventh step (grooving step) P6, in the die-sinking electric discharge machining, the shape of the groove is formed on the portion corresponding to the outer peripheral surface 13 of each side portion 21 of the pellicle frame 1 with respect to the sintered body. The recess 25 of the above was formed.

Specifically, die-sinking electric discharge machining was performed using an electrode having an inverted groove shape.
(8th step P8)
Next, in the eighth step (through hole drilling step) P8, a ventilation hole 27, which is a through hole for adjusting the atmospheric pressure, was formed in the bottom 25c of the recess 25 by a small hole electric discharge machine (not shown).

Two ventilation holes 27 were formed in each recess 25.
(9th step P9)
Next, in the ninth step (surface treatment step of the electric discharge machined surface) P9, the surface treatment of the surface (that is, the electric discharge machined surface) subjected to the electric discharge machining in the above-mentioned fifth to eighth steps P5 to P8 was performed.

Specifically, the heat-altered layer generated by electric discharge machining was removed by sandblasting. In the sandblasting treatment, silicon carbide abrasive grains having a particle size of # 600 (average particle size of about 30 μm) were used. The thickness of the removed layer was about 5 μm.
(10th step P10)
Next, in the tenth step (precision flat surface processing step) P10, precision flat surface processing was performed on the sintered body after the sandblasting treatment.

In this precision flat surface processing, a diamond grindstone was used to polish each side of the sintered body by 25 μm to 50 μm, and the thickness was 2.0 mm and the flatness was reduced to less than 10 μm.

Through the above treatment, a pellicle frame 1 containing alumina as a main component was obtained.

When the Young's modulus and the strength of the pellicle frame 1 were measured, the Young's modulus was 420 GPa and the strength was 690 MPa.

The ridge portion of the formed pellicle frame 1 may be brush-polished and chamfered with an R radius of 0.03 mm to 0.05 mm.

Then, the filter 5 was attached to the pellicle frame 1 using a well-known adhesive so as to cover all the open ends opened in the outer peripheral surface 13 of each recess 25. That is, the outer edge portion of the filter 5 is attached around the open end of the recess 25.

Then, the pellicle film 3 is arranged on the second surface 15 side of the pellicle frame 1 so as to cover the entire surface of the central through hole 19 of the pellicle frame 1, and the pellicle film 3 is placed on the pellicle frame 1 using a well-known adhesive. It was attached to the second surface 15. That is, the outer edge portion of the pellicle film 3 was attached to the second surface 15 of the pellicle frame 1.

In this way, the pellicle 7 could be manufactured.

[1-4. effect]
(1) In the first embodiment, in each side portion 21, the ventilation area (S1) at the open end of each recess 25, that is, the effective ventilation area (S1) of the filter 5, is two open to the recess 25. Since it is larger than the total cross-sectional area of the vent holes 27, that is, the minimum cross-sectional area (S2) of the vent holes 27, it takes a short time when the pellicle 7 is evacuated through the filter 5 or released to the atmosphere. Can be evacuated and released to the atmosphere.

Further, unlike the conventional case, it is not necessary to provide a special structure inside or outside the pellicle frame 1, so that a preferable shape of the pellicle frame 1 can be easily realized. That is, it is possible to prevent the exposure area from being reduced, the pellicle frame 1 from becoming large, and the configuration from becoming complicated.

Further, the recess 25 can be easily provided even in the pellicle frame 1 which is a frame body having a small diameter. Moreover, since it is not necessary to provide a large number of ventilation holes 27, it is possible to suppress a decrease in the strength of the pellicle frame 1 when a large number of ventilation holes 27 are provided.

(2) In the first embodiment, the ratio (S / V) of ^{the total area (Smm 2} ) of the open ends of all the recesses 25 to ^{the volume (Vmm 3} ) of the inner space of the pellicle frame 1 is 0.002 mm. ^-1 or more and 0.025 mm ^-1 or less. Even in such a case, evacuation and release to the atmosphere can be performed in a short time.

(3) In the first embodiment, since the pellicle frame 1 is made of a conductive ceramic sintered body, the pellicle frame 1 can be easily machined by electric discharge machining.

(4) In the first embodiment, since the pellicle frame 1 has a Young's modulus of 300 GPa or more and a strength of 500 MPa or more, the pellicle frame 1 has sufficient rigidity and strength.

(5) In the first embodiment, since the pellicle frame 1 is made of a ceramic sintered body having a thermal conductivity of 15 W / mK or more, the pellicle frame 1 efficiently uses the heat generated in the pellicle film 3 during exposure. It diffuses well and can prevent the pellicle film 3 from being damaged by heat.

(6) In the first embodiment, since the pellicle frame 1 is made of a ceramic sintered body having a thermal expansion coefficient of 10 ppm / ° C. or less, the pellicle frame 1 is deformed by a temperature rise during exposure. It can be suppressed suitably.

[1-5. Correspondence of wording]
The pellicle frame 1, the first filter 5, the inner peripheral surface 11, the outer peripheral surface 13, the second surface 15, the first surface 17, the side portion 21, the recess 25, the ventilation hole 27, the opening 27a, and the adhesive material of the first embodiment. The layer 33, the ventilation suppressing portion 73, and the second filter 83, respectively, of the present disclosure, the pellicle frame, the first filter, the inner peripheral surface, the outer peripheral surface, the second surface, the first surface, the side portion, the recess, the through hole, and the opening. , Corresponds to an example of an adhesive layer, a ventilation suppression part, and a second filter.

[2. Second Embodiment]
Next, the second embodiment will be described, but the description thereof will be omitted or simplified for the same contents as those of the first embodiment. In addition, the same number is given to the structure which is the same as the 1st Embodiment.

As shown in FIG. 6, the pellicle frame 31 of the second embodiment can collect foreign matter such as dust in the air by adhering it over the entire surface (that is, the inner peripheral surface) of the recess 25 and the ventilation hole 27. Adhesive material layer 33 is formed.

Note that FIG. 6 shows an example in which one vent hole 27 is provided in one recess 25 in one side portion 21, but in each recess 25 of the other three side portions 21. Of these, at least one recess 25 is provided with a plurality of ventilation holes 27 (not shown).

As the material of the pressure-sensitive adhesive layer 33, for example, a material such as the silicone pressure-sensitive adhesive described in Japanese Patent Application Laid-Open No. 2011-107519 can be adopted.

The adhesive layer 33 may be formed in at least a part of the recess 25 and the ventilation hole 27.

The second embodiment has the same effect as that of the first embodiment. Further, since the second embodiment includes the adhesive layer 33, there is an advantage that the ability to collect foreign substances is superior to that of the first embodiment.

[3. Third Embodiment]
Next, the third embodiment will be described, but the description thereof will be omitted or simplified for the same contents as those of the first embodiment. In addition, the same number is given to the structure which is the same as the 1st Embodiment.

As shown in FIG. 7, the pellicle frame 41 of the third embodiment is provided with a concavo-convex portion 43 in which a large number of strip-shaped concavities and convexities are arranged in parallel on the bottom portion 25c of the recess 25. That is, as shown in FIG. 7B, a concavo-convex portion 43 in which the concavo-convex portion is repeatedly arranged so that the bottom portion 25c has a wavy shape (that is, a sine curve shape) is provided.

Further, the pellicle frame 41 of the third embodiment adheres and catches foreign matter such as dust in the air over the entire surface (that is, the inner peripheral surface) of the recess 25 and the ventilation hole 27 as in the second embodiment. A collectable adhesive layer (not shown) is formed.

The third embodiment has the same effect as that of the first embodiment. Further, in the third embodiment, since the uneven portion 43 is provided on the bottom portion 25c of the concave portion 25, there is an advantage that the foreign matter collecting ability is superior to that of the second embodiment.

Note that FIG. 7 gives an example in which two ventilation holes 27 are provided in one recess 25, but the present invention is not limited thereto. That is, as long as a plurality of ventilation holes 27 are provided in at least one recess 25, the number of ventilation holes 27 provided in the other recesses 25 is not particularly limited (the same applies hereinafter).

Further, FIG. 8A shows the pellicle frame 51 of the modified example 1. In the modified example 1, the concave-convex portion 53 having the same shape as the concave-convex portion 43 described above is formed on both sides of the inner peripheral surface of the concave portion 25 in the Z direction. It is formed on the side surfaces 25a and 25b of the above.

In the first modification, the same effect as that of the third embodiment is obtained. The uneven portions 43 and 53 may be provided on both the bottom portion 25c of the concave portion 25 and the both side surfaces 25a and 25b.

Further, FIG. 8B shows the pellicle frame 61 of the modified example 2. In the modified example 2, a plurality of hemispherical convex portions 63 are formed on the bottom portion 25c of the concave portion 25. A plurality of hemispherical recesses (dimples) may be provided.

In the first modification and the second modification, the same effect as that of the third embodiment is obtained.

[4. Fourth Embodiment]
Next, the fourth embodiment will be described, but the description thereof will be omitted or simplified for the same contents as those of the first embodiment. In addition, the same number is given to the structure which is the same as the 1st Embodiment.

As shown in FIG. 9, the filter 5 is attached to the pellicle frame 71 of the fourth embodiment so as to cover the entire open end of the recess 25.

Further, on the outer peripheral surface 13 side (above FIG. 9B) of the filter 5, a sheet-shaped ventilation suppressing portion that suppresses ventilation is directly above the outer peripheral surface 13 side (above FIG. 9B) of the two ventilation holes 27. 73 is pasted. That is, one ventilation suppressing portion 73 having an area wider than both openings 27a is arranged so as to cover the entire facing region facing the openings 27a of the two ventilation holes 27.

The ventilation suppression unit 73 may be provided for each ventilation hole 27.

The ventilation suppressing portion 73 can be formed, for example, by applying an adhesive to the upper surface of the filter 5 and solidifying it.

Further, the pellicle frame 71 of the fourth embodiment adheres and catches foreign matter such as dust in the air over the entire surface (that is, the inner peripheral surface) of the recess 25 and the ventilation hole 27 as in the second embodiment. A collectable adhesive layer (not shown) is formed.

Although the ventilation suppression unit 73 completely prohibits ventilation here, a breathable member having a higher ability to regulate ventilation than the filter 5 may be used.

The fourth embodiment has the same effect as that of the first embodiment. Further, in the fourth embodiment, since the ventilation suppressing portion 73 is provided, the air introduced into the recess 25 from the outside is obstructed by the ventilation suppressing portion 73 and goes straight from the filter 5 (that is, to the filter 5). It will not be introduced into the ventilation hole 27 as it is (flowing vertically to the air). That is, since the air introduced into the recess 25 from the outside travels by bending the flow path at the ventilation suppressing portion 73, the flow path in the recess 25 becomes longer, and the ability to collect foreign matter is higher than that in the second embodiment. It has the advantage of being excellent.

[5. Fifth Embodiment]
Next, the fifth embodiment will be described, but the description thereof will be omitted or simplified with respect to the same contents as those of the first embodiment. In addition, the same number is given to the structure which is the same as the 1st Embodiment.

As shown in FIG. 10, a filter (first filter) 5 is attached to the pellicle frame 81 of the fifth embodiment so as to cover the entire open end of the recess 25.

Further, inside the recess 25, two second filters 83 having higher air permeability than the first filter 5 are arranged. The two second filters 83 are arranged for each opening 27a so as to cover the entire surface of each opening 27a of the two ventilation holes 27.

In the above embodiment, two second filters 83 are arranged so as to individually cover each opening 27a of the two ventilation holes 27, but the present invention is not limited to this, and the second filter 83 can be used for 2 steps. It may be provided so as to cover each opening 27a of the ventilation holes 27. As the second filter 83, a porous body made of sintered metal or ceramic can be used.

Further, the second filter 83 has the pressure-sensitive adhesive layer 33 (not shown in FIG. 10) around its own gas flow path. As the pressure-sensitive adhesive layer 33, the above-mentioned silicone pressure-sensitive adhesive can be used. Since the adhesive layer 33 is formed on the wall surface forming the flow path (for example, in the case of a mesh, the surface of the wire rod forming the net), air can enter and exit through the second filter 83.

The fifth embodiment has the same effect as that of the first embodiment. Further, in the fifth embodiment, since the second filter 83 provided with the adhesive layer 33 is provided, there is an advantage that the foreign matter collecting ability is superior to that of the first embodiment.

[6. 6th Embodiment]
Next, the sixth embodiment will be described, but the description thereof will be omitted or simplified for the same contents as those of the first embodiment. In addition, the same number is given to the structure which is the same as the 1st Embodiment.

As shown in FIG. 11, in the pellicle frame 91 of the sixth embodiment, the corner portion (that is, the portion where the planes intersect vertically) on the inner surface (inner peripheral surface) of the recess 25 is chamfered. That is, the inner corner of the recess 25, that is, the corner of the outer peripheral portion of the bottom 25c, and the corner of the four side surfaces 25a, 25b, 25e, 25f where the adjacent side surfaces 25a, 25b, 25e, 25f intersect. Since the R chamfered portion 93 is formed, the corner portion is smoothly curved.

The recess 25 is provided with three ventilation holes 27.

The sixth embodiment has the same effect as that of the first embodiment. Further, in the sixth embodiment, since the R chamfered portion 93 is provided inside the recess 25, the air flow is along the inner peripheral surface of the recess 25, and foreign matter is collected as compared with the first embodiment. It has the advantage of excellent ability. Further, the R chamfered portion 93 has an advantage that the pellicle frame 1 is not easily damaged.

[7. Experimental example]
Next, an experimental example by calculation or the like will be described.

<Experimental example 1>
In Experimental Example 1, the dimensions of each part of the pellicle frame are specified, and the opening area ratio (S / V) is obtained. When there are a plurality of recesses, the total opening area of all the recesses may be referred to as the total opening area Smax.

Here, the external dimensions of the pellicle frame are 149 mm in length × 115 mm in width, 1.8 mm in thickness W1, and 2 mm in width D1. The inner diameter of the pellicle frame is 145 mm in length × 111 mm in width × 1.8 mm in thickness.

As for the groove (that is, the recess), assuming that the groove length L1, the groove width W2, and the groove depth D2, the opening area S per groove is S = L1 × W2.

It should be noted that L1 = side length of -10 mm and W2 = W1-0.4 mm.

Therefore, the total opening area Smax, which is the total of the opening areas of all the grooves, can be calculated by the following formula (1) (the unit of the numerical value is mm).

Smax = {(149-10) x 2 + (115-10) x 2} x (1.8-0.4) = 683 mm ² ... (1)
On the other hand, since bottomed holes having a diameter of 1.5 mm are provided at two locations on the two opposite sides, a groove cannot be formed in 2 mm in the vicinity of the bottomed holes. Therefore, the loss amount of this bottomed hole is set to 2 × (1.8-0.4) × 4 (location) = 11 mm ² (the unit of the numerical value other than “location” is mm).

Therefore, the exact total open area in consideration of the loss in (Smax [mm ^{2]) is} a 683mm ² -11mm ² = 672mm ^2.

Here, the volume of the inner space surrounded by the inner peripheral surface of the pellicle frame (internal volume: V [mm ³ ]) is 145 mm × 111 mm × 1.8 mm = 28971 mm ³ .

Therefore, the ratio of the total opening area Smax [mm ² ] to the internal volume V [mm ³ ] of the pellicle frame (opening area ratio: Smax / V) is 672 mm ² ÷ 28971 mm ³ = about 0.023 mm ^-1 . Become.

That is, under the above-mentioned conditions, the maximum opening area ratio (Smax / V) is 0.023 mm ^-1 .

<Experimental example 2>
In Experimental Example 2, the dimensions and the like of each part of the pellicle frame are specified, and the time required for evacuation and release to the atmosphere is obtained.

As the filter (first filter), a filter that satisfies the ULPA standard is used.

This ULPA standard is a filter having a particle collection rate of 99.9995% or more with respect to particles having a rated air volume and a particle size of 0.15 μm, and an initial pressure loss of 245 Pa or less. ..

As a test method, the rated air volume of the pellicle frame can be calculated by the following formula (2) based on the JIS B 9927 clean room air filter performance test method specification (test wind speed = 5.3 [cm / sec]). can. Here, the total opening area is simply referred to as the opening area S.

Rated air volume of pellicle frame = wind speed (53 [mm / sec]) x opening area (S [mm ² ])
= 53S [mm ³ / sec] ・ ・ (2)
Further, the time T for evacuating or releasing the pressure difference of 1 atm (100000 [Pa]) to the atmosphere can be obtained from the following formula (3).

T = (Internal volume of pellicle frame ÷ Rated air volume) × (100000 [Pa] ÷ Allowable pressure difference) ・ ・ (3)
Here, assuming that the allowable pressure difference at which the pellicle film is not deformed or damaged is 245 [Pa], the time T can be obtained from the following equation (4). The allowable pressure difference is calculated assuming that it is 245 [Pa] for convenience.

T = {(145 * 111 * 1.8) / (53 * S)} * (100000/245) ≒ 223000 / S [sec] ・ ・ (4)
Further, the minimum value of the opening area of the recess (groove) can be obtained by the following procedure.

That is, assuming that the evacuation time T = 1 hour (3600 [sec]) or less, an opening area of ^{S = 223000/3600 ≈ 62 [mm 2] or more is required.} That is, the minimum value of the opening area of the recess (groove) is 62 [mm ² ].

Further, the required minimum value of the opening area ratio (S / V) can be obtained from the following equation (5).

Aperture area ratio [mm ^-1 ] = 62 [mm ² ] ÷ internal volume V (28971 [mm ³ ]) = 0.002 [mm ^-1 ] ・ ・ (5)
When the groove area is maximized (that is, when S = 672 [mm ² ]), the evacuation time is about 332 [sec] (about 5.5 minutes) from the following equation (6). Become.

T = 223000/672 = approx. 332 [sec] ・ ・ (6)
On the other hand, the maximum value of the opening area ratio (S / V) is 0.023 mm ^-1 from Experimental Example 1.

Accordingly, the scope of the opening area ratio (S / V), in the conditions described above is considered to 0.002 mm ^-1 or 0.023 mm ^-1 or less.

When, for example, the filter medium described in Japanese Patent Application Laid-Open No. 2013-52320 is used as the first filter, the pressure loss is as small as 190 [Pa] or less, and the vacuuming time can be shortened. The cover layer <10 [Pa], the pre-collection layer <80 [Pa], and the main collection layer <100 [Pa].

Further, if only the main collection layer <100 [Pa] is used, the pressure loss is further halved, and the evacuation time can be shortened.

[8. Other embodiments]
It is needless to say that the present disclosure is not limited to the above-described embodiment or the like, and various forms can be adopted as long as it belongs to the technical scope of the present disclosure.

(1) For example, as the material constituting the frame body of the pellicle frame, for example, the conductive ceramics shown in Table 1 below can be adopted. Further, for example, the non-conductive ceramics shown in Table 2 below can be adopted.

Further, as the composition (blending composition) of the conductive ceramics, the compositions shown in Table 3 below can be adopted. Further, as the composition of the conductive material other than ceramics, the composition shown in Table 4 below can be adopted. Further, as the composition of the non-conductive ceramics, the compositions shown in Table 5 below can be adopted.

Nos. 1 to 3 in Table 1 and Nos. 10 to 12 in Table 3 are the same material. Nos. 4 to 6 in Table 1 and Nos. 13 to 15 in Table 4 are the same material. Nos. 7 to 9 in Table 2 and Nos. 16 to 18 in Table 5 are the same material.

(2) Further, as the ceramic material for forming the pellicle frame, various materials such as silicon nitride, zirconia, and composite ceramics of alumina and titanium carbide as disclosed in Japanese Patent Application Laid-Open No. 2016-122091 are adopted. can.

(3) Further, one or a plurality of recesses may be provided on at least one of the four side portions.

(4) The function of one component in each of the above embodiments may be shared by a plurality of components, or the function of the plurality of components may be exerted by one component. Further, a part of the configuration of each of the above embodiments may be omitted. Further, at least a part of the configuration of each of the above embodiments may be added or replaced with respect to the configuration of another embodiment. It should be noted that all aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

Claims (14)

It has a rectangular shape in a plan view, has four side portions corresponding to each side of the rectangular shape, and has first and second surfaces provided on both sides in the thickness direction, and the first surface and the second surface. In a pellicle frame including an inner peripheral surface and an outer peripheral surface connected to a surface,
The outer peripheral surface is provided with one or a plurality of recesses, and the one or a plurality of recesses are provided on one or a plurality of the four side portions.
The one or a plurality of recesses are provided with through holes that penetrate the side portion provided with the recess and open to the inside of the recess and the inner peripheral surface.
Of the one or a plurality of recesses, at least one recess is provided with a plurality of the through holes.
In the recess provided with at least one through hole, the ventilation area (S1), which is the area of the opening end on the outer peripheral surface side of the recess, is the minimum cross-sectional area of the gas flow path formed by the through hole. Larger than the minimum cross-sectional area (S2),
Pellicle frame. The minimum cross-sectional area (S2) is the minimum cross-sectional area of the gas flow path formed by the through-holes when there is one through-hole, and when there are a plurality of through-holes, the minimum cross-sectional area of each of the through-holes. The sum of the minimum cross-sectional areas of each gas flow path.
The pellicle frame according to claim 1. The ratio (S / V) of ^{the total area (Smm 2} ) of the open ends of all the recesses to the ^{volume (Vmm 3} ) of the inner space surrounded by the inner peripheral surface of the pellicle frame ^{is 0.002 mm −. 1 to} 0.025 mm ^-1 ,
The pellicle frame according to claim 1 or 2. A first filter covering the open end on the outer peripheral surface side of the recess is provided.
The pellicle frame according to any one of claims 1 to 3. An adhesive layer is provided on at least one of the inner surface of the recess and the inner surface of the through hole.
The pellicle frame according to claim 4. The inner surface of the recess has irregularities.
The pellicle frame according to claim 4 or 5. In the first filter, a ventilation suppressing portion for suppressing the ventilation of the first filter is provided in a region facing the opening of the through hole.
The pellicle frame according to any one of claims 4 to 6. Inside the recess, a second filter that is more breathable than the first filter and covers the opening of the through hole is provided, and the second filter is provided with an adhesive layer around its own gas flow path.
The pellicle frame according to any one of claims 4 to 7. The corners of the inner surface of the recess are R-chamfered.
The pellicle frame according to any one of claims 1 to 8. The pellicle frame is made of a conductive ceramic sintered body.
The pellicle frame according to any one of claims 1 to 9. The pellicle frame is made of a ceramic sintered body having a Young's modulus of 300 GPa or more and a strength of 500 MPa or more.
The pellicle frame according to any one of claims 1 to 10. The pellicle frame is made of a ceramic sintered body having a thermal conductivity of 15 W / mK or more.
The pellicle frame according to any one of claims 1 to 11. The pellicle frame is made of a ceramic sintered body having a coefficient of thermal expansion of 10 ppm / ° C. or less.
The pellicle frame according to any one of claims 1 to 12. The pellicle frame satisfies the following relational expression.
The pellicle frame according to any one of claims 1 to 13.
50 x minimum cross-sectional area (S2) ≤ ventilation area (S1)

Images