JP6509704B2 - Method of manufacturing pellicle frame and pellicle frame - Google Patents

Description

  The present invention relates to a pellicle frame and a method of manufacturing the same.

  In semiconductor manufacturing, a pellicle in which a transparent thin film (pellicle film) is stretched is used to dust-proof a photomask used in an exposure process of forming a pattern on a semiconductor wafer. In order to arrange this pellicle film away from the photomask by a predetermined distance, a rectangular frame called a pellicle frame is used. Several characteristics are required for this pellicle frame.

  One of them is durability that can withstand strong exposure light such as UV light or excimer laser light. Further, since the pellicle frame is not deformed by the film tension generated when the pellicle film is stretched on the pellicle frame, appropriate mechanical strength and rigidity are also required. In order to satisfy such various characteristics, various devices such as materials and surface processing have been applied to the pellicle frame (see Patent Documents 1 to 3).

Japanese Patent Application Laid-Open No. 7-72617 JP-A-9-166867 Japanese Patent Application Laid-Open No. 11-167198

  However, it has been a difficult task to provide a pellicle frame that can withstand such a demand along with a practical manufacturing method. There is still room for improvement with regard to the pellicle frame and its method of manufacture.

  The present invention has been made to solve at least a part of the above-described problems, and can be realized as the following modes or application examples.

(1) As one embodiment of the present invention, a pellicle frame formed in a frame shape is provided. The pellicle frame may be made of a sintered body having a Young's modulus of 150 GPa or more and a Vickers hardness of 800 or more. The volume resistivity of this sintered body at 20 ° C. may be 1.0 × 10 ⁻³ Ω · cm or less. If the pellicle frame has such physical properties, the durability as the pellicle frame can be sufficiently secured, and the generation of dust and the like can be suppressed, and the dust resistance as the pellicle frame can be satisfied. Moreover, since the volume resistivity is low, electrical discharge machining can be used to form the shape as the pellicle frame. Therefore, the processability is excellent.

(2) Such a pellicle frame may contain the sintered body at least one component of nitride, carbide, silicide or boride which is a conductive inorganic compound having a heat resistance temperature of 1500 ° C. or higher. If these inorganic compounds are used, a pellicle frame having the above-mentioned physical properties can be easily obtained.

(3) Alternatively, the sintered body may contain a component of the high melting point metal material. By including the components of the high melting point metal material, it is possible to easily obtain a pellicle frame having the above-mentioned physical properties.

(4) Such a pellicle frame may use the sintered body as a silicon carbide sintered body. Silicon carbide is a material capable of achieving both high Young's modulus and Vickers hardness, and low volume resistivity, and a pellicle frame having the above-mentioned physical properties can be easily obtained.

(5) Further, the physical properties of the pellicle frame may have a Young's modulus of 250 GPa or more or a Vickers hardness of 1000 or more. In this way, it is possible to provide a pellicle frame which is further excellent in durability and abrasion resistance.

(6) As a second embodiment of the present invention, there is provided a method of manufacturing a pellicle frame having a frame shape. In this manufacturing method, by using a sintered material, a molding step of molding the pellicle frame original large frame shape than the pellicle frame, bake larger shape than the frame shape and firing the molded pellicle frame original A first step of preparing a body, and a second step of obtaining at least one of an inner peripheral surface, an outer peripheral surface and an opening surface of the frame-shaped pellicle frame by wire electric discharge machining of the prepared sintered body May be equipped. By so doing, the pellicle frame can be easily manufactured from the sintered body material. In general, a sintered body has high hardness, and in processing with a drill or a cutting bit, the durability of the processing tool becomes a problem. According to the electric discharge machining, the hardness of the material to be processed does not become a problem, so the pellicle frame can be easily manufactured even using the sintered material.

(7) In such a manufacturing method, wire electrical discharge machining may be performed at least twice on the same surface. If wire electric discharge machining on one surface is performed twice, it is easy to machine the surface machined with rough accuracy by the first process with high accuracy by the second process. Further, the processing speed of the second processing is increased, and it becomes easy to balance the processing accuracy and the processing speed.

(8) Such a manufacturing method may include a third step of removing the altered layer on the surface subjected to the electric discharge machining. According to the method of manufacturing the pellicle frame, since the altered layer generated by the electric discharge machining is removed, the possibility that the altered layer peels off from the surface of the pellicle frame and becomes dust can be reduced.

(9) The removal of the altered layer in the third step may be performed by at least one of blasting, polishing and chemical treatment. The blasting treatment includes treatment using sand blasting, fine iron balls and the like. The difference in the range of surface roughness that can be realized, the treatment time, and the like may be used properly for blasting, polishing, and chemical treatment depending on the manufacturing requirements.

(10) In such a manufacturing method, the through-hole or the bottomed hole may be formed in the frame body of the pellicle frame obtained by the processing including the second step, by pore electric discharge machining. The pellicle frame may be provided with a through hole for communication with the internal space when the pellicle having a pellicle film stretched on one side is installed on a photomask, a bottomed hole for positioning, and the like. Also in such a case, electrical discharge machining can be used. Such electrical discharge machining to form pores is sometimes referred to as pore electrical discharge machining because it uses a thin electrode rod (including a hollow electrode rod) for discharge.

BRIEF DESCRIPTION OF THE DRAWINGS The perspective view which shows the pellicle frame as 1st Embodiment. 2-2 arrow sectional drawing in FIG. Process drawing which shows the manufacturing method of a pellicle frame. Explanatory drawing which shows Young's modulus, Vickers hardness, volume resistivity, and workability of each sample. Explanatory drawing which shows a composition of each sample. Explanatory drawing which shows the relationship between the surface roughness of a sample, and sandblasting time. Explanatory drawing which illustrates the shape of through-hole process by electrical discharge machining. Explanatory drawing which illustrates the shape of the through-hole process by a diamond coating drill.

[Structure of pellicle frame]
FIG. 1 is a perspective view showing the shape of a pellicle frame 10 common to the embodiments of the present invention. Moreover, FIG. 2 is a 2-2 arrow sectional drawing of FIG. In FIG. 2, for convenience of understanding, the pellicle membrane 30 stretched on one side of the pellicle frame 10 is also described. The pellicle frame 10 is stretched on the pellicle frame 10 and called pellicle 40. In the present specification, among all the surfaces of the pellicle frame, when the surface on which the pellicle film is to be tensioned is distinguished, the side on which the pellicle film is to be tensioned in FIG. Is called the "bottom side". In addition, the three surfaces of the both surfaces and the outer surface may be referred to as "the outer peripheral surface", and the inner surface of the pellicle frame may be referred to as the "inner peripheral surface". Moreover, when it is not necessary to distinguish each of these surfaces, it may only be called a "surface."

  As shown in both figures, the pellicle frame 10 is a substantially rectangular frame, and the thickness (cross-sectional vertical and horizontal dimensions) of the rectangular upper and lower straight portions 31 to 34 is four corner portions 51 to 51. Except for 54, they are identical. Further, in the example shown in FIG. 1, the corner portions 51 to 54 are each processed to have a chamfer of 45 degrees on the outer periphery and a 1⁄4 arc on the inner periphery. The shapes of the corner portions 51 to 54 are not limited to the above, but may be linear processing such as chamfering, curvilinear (including arc, elliptical arc, parabola, free curve, etc.) processing, and a combination of these. The combination of which shape is the outer circumference and the inner circumference is also arbitrary. Moreover, it is also safe to make part or all of the corner parts 51-54 into a mutually different shape. In the present embodiment, the width of the corner portions 51 to 54 is defined as the length in the normal direction from the surface on the outer peripheral side, but the minimum portion is about 2.2 mm, and the width of the linear portion is 2.0 mm I made it wide. Therefore, in the pellicle frame 10, the strength of the corner portion is higher than that of the straight portion.

  Such a pellicle frame 10 is manufactured by a manufacturing method to be described later. First, a common structure of the pellicle frame formed of a sintered body will be described, and then manufactured by an embodiment of a manufacturing method and various manufacturing methods. The embodiments of the pellicle frame will be described in order.

  The pellicle frame 10 is provided with four bottom holes 12 and 14 with a diameter of 1.6 mm in the left and right frames. The bottomed holes 12 and 14 are, as shown in FIG. 2, bottomed round holes, and the bottoms are arranged in a conical shape. The bottomed holes 12 and 14 are used for manufacturing the pellicle and positioning for subsequent attachment to a photomask. At the time of positioning, positioning pins provided on a pellicle manufacturing apparatus or pellicle mounting apparatus (not shown) are fitted in the four bottomed holes 12 and 14.

  In the lower and upper sides of the pellicle frame 10, through holes 20 with a diameter of 0.5 mm are respectively provided. After the pellicle 40 is attached to the photomask, the through hole 20 is used to adjust the pressure of the space surrounded by the pellicle and the photomask and the external environment. A filter (not shown) is provided in the through hole 20 so that dust does not intrude from the external environment.

[Manufacturing method of pellicle frame]
The pellicle frame 10 shown in FIGS. 1 and 2 is manufactured through the following manufacturing process. This manufacturing process is shown in FIG. A pellicle frame 10 composed of a composite ceramic of alumina, titanium carbide and titanium nitride as a main component of the raw material was manufactured by the following steps. When manufacturing the pellicle frame 10, first, powder is manufactured (process P10). Here, powder refers to a substance that is the source of a sintered body, and for example, a sintering aid is appropriately added to raw material powders such as silicon nitride, zirconia, or alumina, etc. It is made into 100 μm granules. As an example, 63% of α-alumina powder having an average particle diameter of 0.5 μm, 10% of titanium carbide having an average particle diameter of 1.0 μm, 25% of titanium nitride having an average particle diameter of 1.0 μm, and the balance being MgO: Y ₂ O ₃ = 1 Composite materials comprising the sintering aids of No. 1 were wet-mixed, and after adding an organic binder for molding, an alumina-titanium carbide-titanium nitride composite ceramic base powder was produced by a usual spray drying method. In addition, although the measurement of the particle size of raw material powder was performed by the laser diffraction and the scattering method, you may perform by the dynamic light scattering method or the sedimentation method.

  Next, this powder is molded, for example, by a die pressing method to form an original shape of a pellicle frame (process P20). In the present embodiment, the outer dimensions are formed so as to be about 182 mm in the vertical direction (vertical direction in FIG. 1) × 146 mm in the horizontal direction (in the horizontal direction in FIG. 1) × 7 mm in the frame (cross section). Since the outer shape of the pellicle frame is shrunk by about 20 to 30% in the firing step described later, the outer shape of the pellicle frame is previously formed larger than the pellicle frame after firing. The pellicle frame can have various sizes in accordance with the size of the exposure mask in the semiconductor exposure apparatus.

After molding the powder, the powder is removed from the binder and calcined by holding it in an inert gas at a predetermined temperature (eg, 1700 ° C.) for a predetermined time (eg, 3 hours) (step P30). The firing temperature depends on the composition of the powder. By firing, a compact, black composite ceramic sintered body having conductivity, that is, having high Young's modulus and hardness was obtained. Moreover, the volume resistivity at 20 degrees C of the obtained sintered compact was 1.0 * 10 < ^-3 > ohm * cm or less. The Young's modulus, hardness, and volume resistivity of the sample, including the alumina-titanium carbide-titanium nitride composite ceramic exemplified above, will be described later.

  After firing, the outer shape is processed to a predetermined size by electrical discharge machining (step P40). Since the outer shape of the pellicle frame shrinks by about 20 to 30% by firing, dimensional variations of 0.5 to 1.0 percent are inevitable, and in order to obtain dimensional accuracy, the outer shape is processed after firing, Make it the desired size. The machining of the outer shape of the present embodiment was performed by electrical discharge machining. By electric discharge machining, as dimensions at the time of using as a pellicle frame, it was processed into 149 mm long × 120 mm wide × 3 mm frame. Electric discharge machining is wire electric discharge machining, and electric discharge machining is performed at least twice in order to make the machined surface smooth. By performing twice or more, dimensional accuracy and flatness of about 20 μm can be obtained. The electric discharge machining was performed not only on the outer periphery including the outer chamfering of the corner portions 51 to 54 of the pellicle frame 10, and on the inner periphery including the inner radius R of the corner portions 51 to 54. The electric discharge machining may be performed once or three or more times.

  Subsequently, hole processing is performed (process P50). Hole processing is bottomed holes 12 and 14 and through holes 20. These holes are also machined by electrical discharge machining. The diameter of the holes is 2 mm or less in all cases, so it is carried out by pore electric discharge machining using a thin electrode rod (in some cases, a pipe shape). An example of drilling will be described later.

  After drilling, finish processing is performed (process P60). The finishing process is a process for removing the deteriorated layer formed on the machined surface by the electric discharge process. In the present embodiment, blasting is performed. Various techniques are known for blasting, but in the present embodiment, a modified layer of the surface of pellicle frame 10 is subjected to sandblasting with silicon carbide abrasive grains of particle size # 600 (average particle size about 30 microns) for about 2 minutes Was removed. Of course, chemical methods or mechanical polishing may also be used. As a chemical method, for example, a wet method such as removal with concentrated sulfuric acid can be adopted. Alternatively, mechanical polishing such as bubbling may be used.

  The sample of the pellicle frame 10 of the embodiment was manufactured by the above steps. At the time of manufacture of the sample of pellicle frame 10, a test piece was manufactured together. The test piece was finished to an outer dimension of 40 mm × 30 mm and a thickness of 4 mm by the same process as the manufacturing process of the pellicle frame 10 described above. Removal of the surface degenerated layer was similarly performed by sand blasting with silicon carbide abrasive grains. The Young's modulus, Vickers hardness, volume resistivity, surface hue, etc. described later were all measured by this test piece, but are considered to have the same physical properties, so in the following description, all will be described as the Young's modulus of the pellicle frame etc. .

[Sample of pellicle frame]
In the embodiment described above, in addition to the sample of alumina-titanium carbide-titanium nitride composite ceramic (sample No. 1), the sample of zirconia-titanium nitride (sample No. 2), the sample by cemented carbide (sample No. 3), comparison An exemplary alumina-titanium carbide sample (Sample No. 4) was prepared. The production process of each sample is basically the same as the production process shown in FIG. 3, but an appropriate firing temperature, firing time, blasting and the like are selected according to the properties of the material.

  FIG. 4 shows the Young's modulus, Vickers hardness, and volume resistivity of these samples. FIG. 5 also shows the composition of these samples. Furthermore, FIG. 6 is an explanatory view showing the relationship between the surface roughness of the alumina-titanium carbide-titanium nitride composite ceramic of sample No. 1 and the sand blasting time.

As shown in FIG. 4, each of Samples 1, 2, 3 and 4 has a Young's modulus of 250 GPa or more and a Vickers hardness of 1000 or more. Samples 1, 2 and 3 have a volume resistivity of not more than 1.0 × 10 ⁻³ Ω · cm, and the volume resistivity of alumina-titanium carbide sample 4 is 2.1 × 10 ⁻³ Ω · cm. there were. As shown in FIG. 4, the machinability by electrical discharge machining was “good” for samples 1 to 3 and “defective” for sample 4. "Defective" indicates that although it can not be processed if the processing speed is low, it has been determined that the deteriorated layer is thick and that it can not be put to practical use in terms of processing speed. Due to the characteristics of electrical discharge machining, in the case of an insulator with high volume resistivity, machining can not be performed in the first place. If the volume resistivity is 1.0 × 10 ⁻³ Ω · cm or less, good processability is obtained in the electric discharge machining (process P40) and pore electric discharge machining (P50) of the outer shape.

Good machinability by electrical discharge machining means that the following requirements are satisfied.
(1) The processing speed is fast. In the example, it was 4 mm / min in the first (rough processing) of electric discharge machining (drilling) and 6 mm / min in the second (finishing).
(2) There is little wear of processing tools, and the cost is low. In the electric discharge machining, even if the hardness of the object is high, the machining is performed by melting and scattering by electric discharge, so that the machining tip or the like is not worn or damaged. Also, the discharge wire is a copper wire or a brass wire, and it is cheaper than the cutting tip even if it is consumed.
(3) The machining accuracy of the machined surface is sufficiently high. As described later, even when sandblasting was not performed, the arithmetic mean roughness Ra of the surface was 1 μm or less, and the maximum height roughness was 10 μm or less.
(4) In the formation of pores or in the formation of holes with a bottom, distortion due to residual stress or flaws on the exit side of through holes do not occur.

  Regarding the above (2), in the present embodiment, a brass wire of 0.2 0.2 mm is used for electrical discharge machining, so the cost of consumables can be extremely low. On the other hand, when machining the outer periphery and the inner periphery of a machining center equipped with diamond bits for comparison, frequent replacement of expensive diamond bits is required, resulting in a large process load. Moreover, about said (3), as shown in FIG. 6, the surface roughness of the electric-discharge-machined surface was about 0.9 by average surface roughness Ra. In FIG. 6, the sand blasting time of 0 minutes means a state where it has not been processed. However, in the case of electrical discharge machining, the surface of the material to be processed is melted by the electrical discharge, so that a deteriorated layer is formed on the surface of the material to be processed. For this reason, when using as the pellicle frame 10, it is desirable to remove this degraded layer. This point will be described later.

  Regarding (4) above, high drilling accuracy was obtained in EDM. FIG. 7 is an explanatory view showing a processing example of the through hole 20 by electric discharge machining. The diameter of the through hole 20 is 0.5 mm. For this reason, the through-hole 20 was processed using the copper wire of (PHI) 0.4 mm as an electrode. A plurality of through holes were processed, but as seen in FIG. 7, no chipping or the like occurs on the inlet side or the outlet side of the electrode, and the large through hole is outside by the discharge distance (100 μm) than the diameter of the electrode. Been formed.

  On the other hand, as a comparative example, a mode that the through-hole was produced by the diamond coat drill of (PHI) 0.5 mm is shown in FIG. In the figure, the outline of the hole actually opened is indicated by a solid line. As shown, at the processing drill inlet side, the occurrence of chipping was not seen so much. Occurrence of a large chipping was seen on the processing drill outlet side. Of course, these are only examples, but when about 10 holes were machined, in the case of a diamond-coated drill, chipping occurred on the outlet side in total. On the other hand, in EDM, no chipping was observed.

  Furthermore, although illustration is omitted, even when the bottomed hole 12 with a diameter of 1.6 mm is machined, generation of burrs on the inlet side is not observed in electrical discharge machining (pore electrical discharge machining with a copper wire of 1.5 diameter). The On the other hand, when processing with a diamond coat drill, up to 200 μm chipping occurred on the inlet side. In addition, damage to the diamond-coated drill was severe, requiring replacement of the drill every six holes.

As described above, when a conductive material is used for the pellicle frame 10, electric discharge machining can be performed, and the machinability and machining accuracy are excellent. The arithmetic mean roughness of the surface was 0.9 μm. In the present embodiment, the surface is finished by sandblasting in the finishing process. As shown in FIG. 6, the surface of the pellicle frame 10 which is not sandblasted is
Arithmetic mean roughness Ra is 0.9 μm
The 10-point average roughness Rz JIS is 4.0 μm
The maximum height roughness Rz was 9.5 μm.
When this was sandblasted, by sandblasting for 1 minute or 2 minutes,
Arithmetic mean roughness Ra is 0.5 to 0.7 μm
10-point average roughness RzJIS is 1.9 to 2.5 μm
Maximum height roughness Rz is 3.8 to 4.5 μm
It has been improved to some extent. In addition, the processing depth was 4.5 μm in 1 or 2 minutes of sandblasting.

  The processing depth is 4.5 μm regardless of the sandblasting time, which is considered to be because the thickness of the modified layer formed on the surface of the pellicle frame 10 by the electric discharge machining is about 4.5 μm.

  Moreover, although not shown in the drawings, the altered layer on the inner peripheral surface of the through hole 20 and the bottomed holes 12 and 14 is also removed by sandblasting, the cross section of the through hole 20 and the bottomed holes 12 and 14 is a microscope It confirmed by observing by. Therefore, it is possible to suppress the occurrence of the problem that a part of the deteriorated layer peels off from the inside of the through hole 20 and enters the inside of the pellicle frame 10. In addition, when positioning the pellicle frame 10 using the bottomed holes 12 and 14, a portion of the altered layer inside the bottomed holes 12 and 14 peels off in contact with the positioning pins, and the pellicle frame 10 is It is possible to suppress the occurrence of problems such as adhesion to the attached pellicle film 30.

As described above, when the pellicle frame 10 is formed of a sintered body having a Young's modulus of 150 GPa or more, a Vickers hardness of 800 or more, and a volume resistivity of 1.0 × 10 ⁻³ Ω · cm or less, the volume The low resistivity enables electrical discharge machining, and the pellicle frame 10 can be easily manufactured. In addition, since the Young's modulus and the Vickers hardness are high, the rigidity and durability necessary for the pellicle frame can be realized together with high processability and reduction of the processing cost.

[Modification]
In the above embodiment, although the alumina-titanium carbide-titanium nitride composite ceramic is used, the sintered body containing a sintered body having a volume resistivity of 1.0 × 10 ⁻³ Ω · cm or less or a refractory metal is used. If the Young's modulus is 150 GPa and the Vickers hardness is 800 or more, another material may be used. A material containing at least one component of nitride, carbide, silicide, and boride that is a conductive inorganic compound having a heat resistance temperature of 1500 ° C. or higher, other than zirconia titanium nitride and a cemented carbide whose samples are shown in FIG. 4 It can be used if it meets the requirements. In addition, refractory metal materials such as tungsten (3387 ° C), rhenium (3180 ° C), tantalum (2996 ° C), osmium (2700 ° C), molybdenum (2610 ° C), niobium (2468 ° C), iridium (2447 ° C), It is also possible to use a sintered body satisfying the above physical properties, including ruthenium (2250 ° C.), hafnium (2150 ° C.) and alloys thereof.

  Furthermore, when such a sintered body satisfies the condition of Young's modulus of 250 GPa or more or Vickers hardness of 1000 or more, the pellicle 1 is more preferable because the durability and abrasion resistance are enhanced.

  Although the hole machining of the bottomed holes 12 and 14 and the through holes 20 has been described as the fine-pore electrical discharge machining, as the name of an actual machining or processing machine, it is called wire electric discharge machining or die-sinking electric discharge machining and its machine There is. In any case, it is possible to use any processing method that utilizes electrical discharge from a conductor such as metal (such as copper or brass) or carbon to a workpiece.

  In the above embodiment, the four corner portions are chamfered at 45 degrees on the outer peripheral side, and rounded at the inner peripheral side. Such chamfering may not be performed, or may be performed only on the outer periphery or the inner periphery. In addition, it is also free to apply simple chamfering or round chamfering to either the outer periphery or the inner periphery. It is not necessary to chamfer all corner portions, and one or more corner portions may be chamfered. It is also desirable that the corner portion in the frame shape of the pellicle frame has a width equal to or greater than the width of the linear portion, and at least one of the corner portions is wider than the linear portion. This is desirable because it can generally increase the strength of the corners where stress is likely to be concentrated.

  As mentioned above, although the embodiment and modification of the present invention were described, the present invention is not limited to these embodiment and modification at all, and can be implemented in various modes in the range which does not change the gist of the present invention. Of course. For example, the shape, size, thickness and the like of the pellicle frame may be the shape, size, and thickness necessary for the pellicle frame. The pellicle frame does not have to be rectangular, and may have, for example, a circular shape, a polygonal shape, or the like. In addition, it is not necessary to perform electric discharge machining on all the surfaces of the pellicle frame, and a specific surface may use another processing method, for example, cutting with a machining center. Alternatively, at least a part of the through hole or the bottomed hole may be formed by cutting using a diamond coat drill or the like.

10 ... pellicle frame 12, 14 ... bottomed hole 20 ... through hole 30 ... pellicle membrane 40 ... pellicle

Claims (10)

It is a pellicle frame formed in a frame shape,
It consists of a sintered body with a Young's modulus of 150 GPa or more and a Vickers hardness of 800 or more,
A pellicle frame having a volume resistivity at 20 ° C. of 1.0 × 10 ⁻³ Ω · cm or less.   The pellicle frame according to claim 1, wherein the sintered body contains at least one component of a nitride, a carbide, a silicide, and a boride which is a conductive inorganic compound having a heat resistance temperature of 1500 ° C. or higher.   The pellicle frame according to claim 1, wherein the sintered body contains a component of a high melting point metal material. The pellicle frame according to claim 1, wherein the sintered body is a sintered body mainly composed of alumina or zirconia .   The pellicle frame according to any one of claims 1 to 4, wherein Young's modulus is 250 GPa or more or Vickers hardness is 1000 or more. A method of manufacturing a pellicle frame having a frame shape, comprising:
A forming step of forming a pellicle frame original of a frame shape larger than the pellicle frame using a sintered material;
A first step of firing the molded pellicle frame original form to prepare a sintered body having a shape larger than the shape of the frame;
A second step of obtaining at least one of the inner peripheral surface, the outer peripheral surface, and the opening surface of the frame-shaped pellicle frame by wire electric discharge machining of the prepared sintered body .   The method according to claim 6, wherein the wire electric discharge machining is performed at least twice on the same surface.   The method for manufacturing a pellicle frame according to claim 6 or 7, further comprising a third step of removing the altered layer of the surface subjected to the electric discharge machining.   The method of manufacturing a pellicle frame according to claim 8, wherein the removal of the altered layer in the third step is performed by at least one of blasting, polishing and chemical treatment.   The method according to any one of claims 6 to 9, further comprising the step of forming a through hole or a bottomed hole in the frame body of the pellicle frame obtained by the processing including the second step by pore electric discharge machining. The manufacturing method of the pellicle frame as described in a term.

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