KR20190125192A - Pellicle frame and method for manufacturing the same - Google Patents

Abstract

The present invention provides a pellicle frame having a high flatness and a method for manufacturing a pellicle frame, capable of manufacturing the pellicle frame. In the method for manufacturing a pellicle frame (1), a sintered body (35) serving as the pellicle frame (1) is fixed to a surface plate (31) without deforming the sintered body (35), and surface processing of an upper surface (second surface) (37) opposite to the surface plate (31) is performed. Thus, the flatness of the sintered body (35) (therefore, the pellicle frame (1)) can be increased. More specifically, the sintered body (35) is fixed to the surface plate (31) with wax (W) without deforming the sintered body (35). Therefore, even if the sintered body (35) is pressed from the second surface (37) when performing the surface processing to improve the flatness, the sintered body (35) is unlikely to be deformed following the surface (33) of the surface plate (31).

Description

PELLICLE FRAME AND METHOD FOR MANUFACTURING THE SAME

The present disclosure relates to a pellicle frame and a method of manufacturing a pellicle frame.

In semiconductor manufacturing, a photomask is used in an exposure step of forming a wiring pattern on a semiconductor wafer. When foreign matter (particles, etc.) adhere to the photomask, defects in the wiring pattern occur.

As a countermeasure, that is, the pellicle is arrange | positioned so that the surface (for example, front and back surface) of a photomask may be covered for dust isolation. This pellicle is a pellicle frame, which is a rectangular frame, in which a transparent thin film (pellicle film) is placed so as to cover the opening.

This pellicle frame is a member made of a wire rod having a thin frame portion and having a large opening area of the opening portion, and is used to arrange the pellicle film at a predetermined distance from the photo mask. As the member constituting the pellicle frame, for example, a member made of, for example, an aluminum alloy having a small diameter, such as a prisms having a thickness of 3 mm × width 2 mm, is used.

By the way, the conventional aluminum alloy pellicle frame (hence the pellicle) has a bad flatness (for example, because the flatness is about several tens of micrometers). Therefore, when the pellicle is affixed to the photomask, deformation such as warpage or distortion in the photomask is applied. There was a problem that this occurred.

As this countermeasure, for example, Patent Literature 1 discloses a technique in which a dent is formed on the sidewall of the pellicle frame, the rigidity of the pellicle frame is reduced, and the deformation of the photomask is suppressed.

Japanese Unexamined Patent Publication No. 2011-7933

However, since the above-mentioned prior art does not improve the top view itself of a pellicle frame, when a pellicle is affixed on a photomask, there exists a possibility that the deformation | transformation of a photomask may not be fully suppressed.

As a countermeasure, for example, using a high-precision planar machine, it is considered that the flatness of the pellicle frame is less than 1 m. For example, as shown to Fig.9 (a), the pellicle frame A2 is mounted on the surface plate A1, and the surface of the thickness direction of a pellicle frame is processed (that is, performing planar processing). Is considered.

By the way, a pellicle frame with a large opening area and a small frame cross section has low rigidity, causes elastic deformation during planar processing, and deforms along the shape of the surface plate. For example, as shown in Fig. 9 (b), the curved pellicle frame is flattened along the flat surface of the surface plate when pressure is applied from the top by grinding wheels during the plane processing, as if the flatness is improved. It becomes a flat state. Therefore, even if it performs planar processing in this state, a flatness will not improve. As a result, as shown in FIG.9 (c), since it returns to an original shape by its elasticity after planar processing, a top view will be in the state which is not improved.

In short, conventionally, since the pellicle frame is only placed on the surface plate and the top surface (that is, the exposed surface) is subjected to planar processing, the pellicle frame is deformed to conform to the surface of the surface surface, and when the pressure is released after the surface processing, Since it returns to a shape, there existed a problem that a flatness did not improve.

The present disclosure has been made to solve the above problems, and an object thereof is to provide a pellicle frame having a high plan view and a pellicle frame capable of manufacturing the pellicle frame.

(1) The first aspect of the present disclosure is based on a frame-shaped pellicle frame having first and second surfaces formed on both sides in the thickness direction, and an inner circumferential surface and an outer circumferential surface in contact with the first and second surfaces. The manufacturing method of a pellicle frame which mounts on a phase and processes a pellicle frame is performed.

In the method for producing a pellicle frame, the pellicle frame is fixed to the foundation in a state where the pellicle frame is placed on the foundation side in the fixing step and the shape of the pellicle frame is maintained, and the pellicle is fixed to the foundation in the fixing process. Plane processing is performed on the second surface of the frame.

Thus, in this 1st aspect, since the pellicle frame is fixed to the base in the state which does not deform | transform, and planar processing of the 2nd surface (exposure surface) which is the surface on the opposite side to the base is performed, the flatness of a pellicle frame can be raised.

Specifically, in the first aspect, the pellicle frame is fixed to the foundation with, for example, wax or the like without deforming the pellicle frame (i.e., maintaining the bad top view if the top view is bad). Therefore, even when the pellicle frame is pressed from the exposed surface side by a grindstone or the like when performing a planar processing on the exposed surface in order to improve the flatness of the pellicle frame, the pellicle frame is hardly deformed along the surface of the foundation. For example, even when the pellicle frame is curved, it is fixed on the foundation while maintaining the curved state (that is, not being elastically deformed).

Therefore, in the state in which the pellicle frame is not elastically deformed, the planar processing on the exposed surface side can be performed to improve the flatness, so that the pellicle frame can be processed so as to be the flatness intended for the purpose.

In addition, in this 1st phase, since the surface processing of the exposed surface side is performed in the state in which the pellicle frame is not elastically deformed, after the surface processing, the front and back surfaces of the pellicle frame produced by the elastic deformation during planar processing (namely, 1st Residual stress difference between the surface and the second surface) can be reduced. Therefore, after planar processing, the pellicle frame can be suppressed from returning to its original state by its elasticity. Therefore, the pellicle frame can maintain the high flatness obtained by planar processing.

Therefore, in this 1st phase, the incidence rate of planar defects falls with respect to a pellicle frame, and a yield improves. Moreover, even when a flatness defect arises, correction is easy. Moreover, since the process of planar processing can be simplified, the number of processes can be reduced significantly.

(2) In the second aspect of the present disclosure, in the state where the pellicle frame is separated from the foundation in the separation step after the planar processing, and the pellicle frame separated in the mounting process is placed on the foundation with the second surface as the foundation side, You may perform planar processing with respect to a 1st surface.

Since the plan view of the second surface of the pellicle frame is reduced by the planar processing in the first aspect, the pellicle frame is hardly deformed when the pellicle frame is placed on the foundation with the second surface as the foundation. That is, since the surface used at the time of planar processing is usually very flat (namely, a flatness is small), when a 2nd planar surface is made into the foundation side, a pellicle frame hardly deforms.

Therefore, the flatness of a 1st surface can also be made small by carrying out planar processing with respect to the 1st surface which is the exposed surface of a pellicle frame which hardly deform | transforms.

Therefore, in this 2nd phase, the top view of both surfaces (namely, 1st surface and 2nd surface) of the thickness direction of a pellicle frame can be made small.

Further, even if a difference in residual stress occurs between the second surface side and the first surface side of the pellicle frame by the planar processing according to the first aspect, in the second aspect, the second surface is placed on the foundation ( In short, unlike the first phase, the pellicle frame is not fixed to the foundation) and the first surface is subjected to planar processing. Therefore, the residual stress equivalent to a 2nd surface can be provided to the 1st surface of a pellicle frame, and the flatness of the 1st surface and the 2nd surface of a pellicle frame can be made small.

(3) In the third aspect of the present disclosure, after the fixing step, the fixed machining step, the separation step, and the tact step, the fixing step, the fixed step, the separation step, and the tact step may be performed again.

In the third aspect of the present disclosure, since the fixing step, the fixed machining step, the separation step, and the tact step are performed twice, the plan view of both surfaces in the thickness direction of the pellicle frame can be further reduced.

(4) In the fourth aspect of the present disclosure, the base used in the mounting processing step may be the same base as or the different base used in the fixed machining step.

The bases used in different processes may be common or may be separate foundations.

(5) In the fifth aspect of the present disclosure, a combination of a single foundation or a plurality of foundations may be used as the basis.

For example, the pellicle frame may be placed on a single foundation and subjected to planar processing. In addition, an auxiliary base (sub base) may be provided on the base (main base) serving as a base, and the pellicle frame may be placed on the sub base to perform planar processing.

(6) In the sixth aspect of the present disclosure, the foundation may have a dimension larger than the external dimension of the pellicle frame in plan view.

As described above, in the case where the foundation has an outer dimension larger than that of the pellicle frame, the entire pellicle frame can be arranged on the foundation, so that the pellicle frame can be easily fixed or planarized.

(7) In the seventh aspect of the present disclosure, the foundation may have a characteristic that is not deformed during planar processing.

When the foundation has a property that is not deformed at the time of planar processing of the pellicle frame, the pellicle frame is less likely to deform during planar processing. Therefore, planar processing which improves the flatness of a pellicle frame can be performed preferably.

(8) In the eighth aspect of the present disclosure, the Young's modulus of the base may be 200 GPa or more. In the case where the Young's modulus of the base is 200 GPa or more, since it has high rigidity, the base is hardly deformed during the planar processing of the pellicle frame. Therefore, planar processing which improves the flatness of a pellicle frame can be performed preferably.

(9) In the ninth aspect of the present disclosure, in the fixing step, the pellicle frame may be fixed by a fixing member disposed between the base and the pellicle frame.

By using the fixing material in this way, the pellicle frame can be fixed to the foundation.

(10) In the tenth aspect of the present disclosure, when the pellicle frame is separated from the foundation after planar processing, the pellicle frame may be separated by removing the fixing material between the base and the pellicle frame.

In this way, the pellicle frame can be separated from the base by removing the fixing material after the planar processing of the fixing processing step.

(11) In the eleventh aspect of the present disclosure, in the fixing step, the fixing member may be solidified by filling the fixing member in an unsolidified state between the base and the pellicle frame to fix the pellicle frame.

The pellicle frame can be fixed to the foundation by filling the non-solidified fixing material between the base and the pellicle frame and then solidifying the fixing material.

(12) In the twelfth aspect of the present disclosure, the fixing member is a liquid bonding material, and the liquid bonding material may be filled between the base and the pellicle frame, and then solidified and fixed.

This twelfth aspect illustrates a method in the case of using a liquid bonding material as the fixing material.

(13) In the thirteenth aspect of the present disclosure, the fixing material is wax, and the wax in the solid state may be heated to be liquefied, filled between the base and the pellicle frame, and then cooled to solidify the wax to fix it. .

This thirteenth aspect illustrates a method in the case of using wax as the fixing material.

(14) In the 14th aspect of this indication, 3 micrometers or less (preferably 1 micrometer or less) may be sufficient as the top view of the surface (namely, mounting surface) in which the pellicle frame in a base is mounted.

In the fourteenth aspect, since the flatness of the mounting surface of the base is small and flat, deformation of the pellicle frame can be suppressed when the pellicle frame is placed on the foundation.

(15) In the fifteenth aspect of the present disclosure, the pellicle frame may include ceramic as the main component.

This 15th aspect illustrates the preferable material of a pellicle frame. In addition, a main component has shown that the said ceramic component is 50 volume% or more of the material which comprises a pellicle frame.

(16) A sixteenth aspect of the present disclosure relates to a pellicle frame having first and second surfaces formed on both sides in a thickness direction, and an inner circumferential surface and an outer circumferential surface that are in contact with the first and second surfaces. The difference in residual stress between the first and second surfaces of the frame is 5 MPa or less.

Thus, when the difference of the residual stress of the 1st surface and the 2nd surface of a pellicle frame is 5 Mpa or less, the pellicle frame itself is hard to deform | transform, and its flatness is small. Therefore, when a pellicle is affixed on the surface of a photomask, since a photomask is hard to deform | transform, it is preferable.

(17) A seventeenth aspect of the present disclosure relates to a pellicle frame having a first surface and a second surface formed on both sides in a thickness direction, and an inner circumferential surface and an outer circumferential surface in contact with the first and second surfaces. 5 micrometers or less of the top view in the 1st surface and the 2nd surface of a frame may be sufficient.

Thus, when the flat surface in the 1st surface and the 2nd surface of a pellicle frame is 5 micrometers or less, when a pellicle is affixed on the surface of a photomask, since a photomask is hard to deform | transform, it is preferable.

<Hereinafter, the configuration of the present disclosure will be described>

-Flat surface processing means the process which flattens the surface of a workpiece | work, Here, in order to improve the flatness in the surface of the thickness direction of a pellicle frame, processing, such as grinding and grinding | polishing, is performed to the surface of a pellicle frame. .

The plan view is "deviated size from the geometrically correct plane of the planar body", and is defined in JIS 0621-1984.

The plan view of the foundation is smaller than the plan view of the pellicle frame (ie, sintered body) before the planar processing and the pellicle frame after the planar processing. In addition, the rigidity of the foundation is higher than that of the pellicle frame, and even when the same force is applied, the foundation is more difficult to deform than the pellicle frame.

As the material of the frame of the pellicle frame, a material mainly composed of ceramic, a material made of cemented carbide, a material made of cermet, a material made of a single metal or an alloy metal can be used. .

As the ceramic, non-conductive ceramics such as alumina, silicon nitride, zirconia, conductive ceramics such as alumina titanium carbide, alumina titanium carbide titanium nitride, zirconia titanium carbide, and the like can be adopted. As the metal, an aluminum alloy or the like can be adopted.

As a dimension of a pellicle frame, the width | variety and thickness of a frame part can employ | adopt the range of 2.0 mm-5.0 mm, for example. As a dimension of an opening part (namely, a center through hole), the range of 110 mm-120 mm in length and 140 mm-145 mm in width can be employ | adopted, for example.

As a base material, ceramics, such as alumina, aluminum nitride, and silicon carbide, can be employ | adopted, For example, 5 mm or more can be employ | adopted as the thickness.

1 is a perspective view illustrating a pellicle frame according to the first embodiment.
It is sectional drawing which shows the cross section which cut | disconnected the pellicle frame of 1st Embodiment along the XY plane.
3 is a cross-sectional view taken along AA in FIG. 1.
It is process drawing which shows the manufacturing method of the pellicle frame of 1st Embodiment.
It is explanatory drawing which shows a part of planar processing in the manufacturing method of the pellicle frame of 1st Embodiment.
It is explanatory drawing which shows another part of planar processing in the manufacturing method of the pellicle frame of 1st Embodiment.
It is explanatory drawing which shows planar processing in the manufacturing method of the pellicle frame of 2nd Embodiment.
8 is an explanatory diagram of Experimental Example 2. FIG.
9 is an explanatory diagram of a prior art.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of the pellicle frame to which this indication was applied, and its manufacturing method is demonstrated using drawing.

[One. 1st Embodiment]

[1-1. Full configuration]

First, the whole structure of the pellicle frame of 1st Embodiment is demonstrated.

As shown in FIGS. 1-3, the pellicle frame 1 is a member in which the pellicle film 3 (refer FIG. 3) is installed in one side (upper of FIG. 3). 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 containing titanium carbide). In addition, in FIG. 1 and FIG. 2, the pellicle frame 1 itself is shown, In FIG. 3, the pellicle 5 in which the pellicle film 3 was installed in the single side | surface of the pellicle frame 1 is shown.

In addition, below, the inner surface surrounded by the pellicle frame 1 itself among all the surfaces of the pellicle frame 1 is called the inner peripheral surface 7, and the outer surface on the opposite side to the inner side is the outer peripheral surface 9. In addition, the side in which the pellicle film 3 was installed among the surfaces which are in contact with the inner peripheral surface 7 and the outer peripheral surface 9 is called the upper surface 11, and the opposite surface is called (13). In addition, when it is not necessary to distinguish these surfaces, it may only be called surface.

As shown in FIG. 1, in the coordinate system of the orthogonal X-axis, Y-axis, and Z-axis, the pellicle frame 1 is a rectangular frame body (that is, an annular member) when viewed in a plane viewed from the Z direction, The center has a rectangular central through hole 15 in plan view.

That is, the pellicle frame 1 consists of a long frame part arrange | positioned in the up, down, left, and right directions in plan view on the same plane. Specifically, the pellicle frame 1 includes the first frame portion 1a and the second frame portion 1b arranged in parallel in the X axis, the third frame portion 1c and the first frame arranged in parallel in the Y axis. It consists of four frame parts 1d.

In addition, the external dimension of the pellicle frame 1 is about 149 mm long (Y direction) x horizontal (X direction) about 120 mm x thickness (Z direction) about 3 mm, for example. In addition, each frame part 1a-1d of the pellicle frame 1 is a square pillar, and the dimension of the width (dimension of the width seen from the Z direction) is the same (for example, about 2 mm).

Moreover, this pellicle frame 1 has the characteristic whose Young's modulus is 150 GPa or more, and Vickers hardness is 800 Hv or more. Moreover, the top view (in detail, the top view of the upper surface 11 and the lower surface 13) of the pellicle frame 1 is 5 micrometers or less. In addition, the difference of the residual stress of the upper surface 11 and the lower surface 13 of the pellicle frame 1 is 5 Mpa or less.

As shown in FIG. 2, the said pellicle frame 1 has two frame parts (namely, the 3rd frame part 1c and the 4th frame part 1d) in an X direction, respectively. At the point (total four points), bottomed holes 17a, 17b, 17c, 17d (generally referred to as 17) which are recesses opened on the outer circumferential surface 9 side are formed.

As shown in FIG. 3, this bottomed hole 17 is a bottomed round hole having a diameter of 1.5 mm and a depth of 1.2 mm, for example, and the bottom is aligned in a conical shape.

The bottomed hole 17 is used for the manufacture of the pellicle 5 and for positioning when mounting it on a subsequent photo mask (not shown).

In addition, as shown in the said FIG. 1 and FIG. 2, the ventilation hole 20 which is a through hole of (phi) 0.5mm is formed in the 3rd frame part 1c of the pellicle frame 1, for example. After the pellicle 5 is attached to the photomask, the vent hole 20 is used for adjusting the air pressure of the space surrounded by the pellicle 5 and the photomask and the external environment. Moreover, the filter which is not shown in figure is formed in the ventilation hole 20 so that dust may not intrude from an external environment.

[1-2. Outline of the manufacturing method of the pellicle frame]

Next, the outline of the manufacturing method of the pellicle frame 1 is demonstrated.

(1st process P1)

As shown in FIG. 4, the powder (namely, a ground powder) which is a raw material of the pellicle frame 1 was manufactured.

Here, powder is a substance which becomes the basis of the sintered compact which comprises the pellicle frame 1, As mentioned later, after sintering adjuvant etc. are appropriately added and wet-mixed to raw material powders, such as an alumina and an electroconductive material, it is spray-dried by It is manufactured from granules of 50 µm to 100 µm.

In addition, although the raw material powder particle diameter was measured by the laser diffraction scattering method, you may perform it by the dynamic light scattering method or the sedimentation method.

(2nd process P2)

Next, this powder was shape | molded and the circular shape of the pellicle frame 1 was formed.

(3rd process P3)

Next, after the said powder molding, this was baked at predetermined temperature.

Although this firing temperature is based on the composition of powder, it is generally 1500 degreeC or more. By baking, the sintered compact (that is, the sintered compact which comprises the pellicle frame 1) which has high Young's modulus and strength is obtained.

(4th process P4)

Next, the thickness process (specifically, the grinding process) which adjusts the thickness with respect to the sintered compact was performed.

In addition, the thickness was made constant here, leaving polishing margin (for example, 0.05 mm-0.10 mm) of the precision planar process (9th process P9) mentioned later.

(5th process P5)

Next, the inner mold and outer mold were processed on the sintered body after the thickness processing.

Specifically, the outer circumferential surface of the sintered body was gripped with a holding jig (not shown), wire discharge processing was performed on the inner circumferential surface and the outer circumferential surface of the sintered compact, and processed into dimensions for the purpose of inner mold or outer mold.

(Sixth Step P6)

Next, the sintered compact after internal mold and external form process was surface-treated of the electrical discharge machining surface.

In detail, the thermally deteriorated layer generated by the electric discharge machining was removed by sandblasting.

(7th process P7)

Next, the punching process was performed about the sintered compact after the surface treatment of an electric discharge machining surface.

Specifically, the bottomed hole 17 was formed in the side surface of a sintered compact by the dicing king electric discharge process. Moreover, the ventilation hole 20 for air pressure adjustment was formed in the side surface of a sintered compact by a thin hole electric discharge machine (not shown).

(Step 8 P8)

Next, surface treatment of the electric discharge machining surface was performed with respect to the bottomed hole 17 and the ventilation hole 20.

In detail, the thermal alteration layer which generate | occur | produced on the inner periphery of the bottom hole 17 and the ventilation hole 20 by discharge processing was removed by sandblasting process.

(Ninth process P9)

Next, the planar view of the upper surface 11 and the lower surface 13 of the pellicle frame 1 will be described later in detail with respect to the sintered body after the sandblasting treatment of the bottomed hole 17 and the vent hole 20. Precision plane processing was performed to improve.

(Step 10 P10)

Thereafter, the pellicle frame 1 may be chamfered.

[1-3. Example]

Next, the specific Example of the manufacturing method of the pellicle frame 1 is demonstrated in detail.

(1st process P1)

In this manufacturing process, 63 vol% of α-alumina powder having an average particle diameter of 0.5 µm, 10 vol% of titanium carbide having an average particle diameter of 1.0 µm, 25 vol% of titanium nitride having an average particle diameter of 1.0 µm, and the balance of MgO: Y ₂ O ₃ A composite material composed of a sintering aid of = 1: 1 was prepared.

Then, the composite material was wet mixed, an organic binder for molding was added, and then a composite ceramic body powder of alumina, titanium carbide, or titanium nitride was prepared by a conventional spray drying method.

(2nd process P2)

In this molding step, the composite ceramics powder is molded into a frame shape of about 182 mm long by 147 mm wide by 6 mm thick by 5 mm in width by a mold press method, and the circular shape of the pellicle frame 1 is obtained. (Powder molding) was prepared.

Here, since the external shape of the pellicle frame 1 is reduced by about 20 to 30% by the baking process mentioned later, it shape | molds larger than the pellicle frame 1 after baking previously. In addition, the pellicle frame 1 can be various sizes according to the size of the mask for exposure in a semiconductor exposure apparatus.

(3rd process P3)

In this firing step, the powder compact was debindered and baked in an inert gas at 1700 ° C. for 3 hours to obtain a compact ceramic sintered body having conductivity.

The dimension of this sintered compact was about 151 mm x 122 mm x thickness 5 mm, and frame width 4 mm. There was also a distortion of about 0.3 mm.

(4th process P4)

In this thickness processing process, the upper and lower surfaces (both sides in the thickness direction) of the sintered body were ground in the same amount in a planar grinding mill and processed to a thickness of 3.1 mm. Moreover, the top view of both surfaces after planar grinding of the sintered compact was 20 micrometers-40 micrometers, respectively.

(5th process P5)

In this inner mold and outer mold machining step, the inner mold and the outer mold of the sintered compact were processed to a length of 149 mm × 120 mm in width and a frame width of 2 mm by wire discharge machining. Moreover, you may perform R process of the edge part (corner part) at this time.

(Sixth Step P6)

In the surface treatment process of this electrical discharge machining surface, the heat-deterioration layer of the electrical discharge machining surface was removed by sandblasting process. In the sand blasting process, 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.

(7th process P7)

In this punching treatment, a φ1.5 mm and a depth of 1.2 mm depth are applied to the sintered body, that is, the third frame portion 1c and the fourth frame portion 1d of the pellicle frame 1 by dicing king discharge processing. The hole 17 was formed.

Moreover, the ventilation hole 20 for air pressure adjustment of (phi) 1mm was formed with respect to a sintered compact by a thin hole discharge process.

(Step 8 P8)

In the surface treatment process of this electrical discharge machining surface, the thermally altered layer of the inner periphery of the bottom hole 17 and the ventilation hole 20 which were discharge-processed by the sand blasting process was removed.

In the sand blasting process, 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.

(Ninth process P9)

Next, using a planar machine, precision planar processing was sequentially performed on each side of the sintered body after the sand blasting process, and each single side was processed to have a flatness of 5 µm or less.

Hereinafter, this precision plane processing is demonstrated in detail using FIG. 5 and FIG. In addition, in FIG. 5 and FIG. 6, the shape of each member, such as the sintered compact 35, is shown typically, highlighting a characteristic.

First, as shown to Fig.5 (a), on the surface (upper surface) 33 of the surface plate (sub surface plate) 31 which has high rigidity, the sintered compact after the process by 8th process P8 (namely, a pellicle frame ( The sintered compact 35 which comprises 1) was mounted so that one surface (second surface) 37 of the thickness direction might become upper side.

As the sub surface plate 31, for example, a plate made of alumina, having a thickness of 5 mm or more (eg, 10 mm) and a top view of 3 μm or less (eg, 0.8 μm) was used. Moreover, the sub surface plate 31 has the dimension larger than the external dimension of the sintered compact 35 in plan view (when seen from the thickness direction), and the thickness is constant. Moreover, the sub surface plate 31 has high rigidity whose Young's modulus is 200 GPa or more (for example, 300 GPa) so that it may not be deformed at the time of planar processing.

Next, the sub surface plate 31 on which the sintered body 35 is placed is placed on a hot plate (not shown), and the solid wax W (in detail, Nikka Seiko Co., Ltd. sky wax) is disposed around the sintered body 35. It was.

And the wax W was heated and melted by the hot plate. As shown in FIG.5 (b), the molten wax W penetrated the clearance gap 39 of 20 micrometers-50 micrometers of the sintered compact 35 and the sub surface plate 31 without bubbles.

Next, the heating of the hot plate was stopped and the wax W was solidified by natural cooling. Thereby, the sintered compact 35 was fixed to the sub surface plate 31 by the wax (W). Moreover, the temperature difference of the upper surface 33 and the lower surface 34 of the sub surface plate 31 at the time of cooling and solidifying the wax W is 1 degrees C or less. If the temperature difference between the upper surface 33 and the lower surface 34 during cooling is large, the sub surface plate 31 causes bending deformation, and when the bending deformation of the sub surface plate 31 is eliminated after cooling, bending in the reverse direction to the sintered body 35. This is because there may be a remaining state.

Moreover, the process of fixing this sintered compact 35 to the sub surface plate 31 using the wax W is an example of a fixing process.

Next, as shown to FIG. 5 (c), the sub surface plate 31 to which the sintered compact 35 was fixed was attached to the planar processing machine 41. Next, as shown in FIG.

Specifically, the sub surface 31 to which the sintered compact 35 was fixed was arrange | positioned on the surface (upper surface) 45 of the surface plate (main surface plate) 43 of the planar processing machine 41. Specifically, the plastic frame 40 having the opening 40a corresponding to the outer shape of the sub surface 31 is fixed to the surface 45 of the main surface plate 43, and the frame body 40 is The sub surface plate 31 was fixed on the main surface plate 43 by sandwiching the sub surface plate 31 in the opening portion 40a.

Moreover, the main surface plate 43 is a horizontal surface plate, and the surface 45 is horizontal. Therefore, the sub surface plate 31 is also a horizontal surface plate, and the surface (upper surface) 33 is also horizontal. In addition, the top view of each surface 45 and 33 of the main surface plate 43 and the sub surface plate 31 is 3 micrometers or less, Preferably it is 1 micrometer or less.

This planar processing machine 41 is a rotary plane grinding disk, for example, and the surface 45 is parallel to the main surface plate 43 above the horizontal disk-shaped main surface plate 43 and the main surface plate 43. The disk-shaped grindstone 47 arrange | positioned is provided. In addition, the rotation axis of the main surface plate 43 and the grindstone 47 is vertical.

Then, while the main surface plate 43 and the grindstone 47 rotate in opposite directions, the grindstone 47 descends to grind the exposed surface of the sintered body 35 as a work, thereby performing planar processing. In addition, when the grindstone 47 descends, it grind | pulverizes about several mm in a horizontal direction (for example, the left-right direction of FIG.5 (c)), and grinds.

Moreover, the planar super finishing board was used as the planar processing machine 41.

Here, by using the planar processing machine 41, as shown in FIG. 6 (a), the planar processing is performed to flatten the second surface 37 of the sintered body 35 by the grindstone 47. The top view of the two sides 37 was processed to 5 micrometers or less.

Next, as shown to FIG. 6 (b), the sub surface plate 31 which mounted the sintered compact 35 after the process of the 2nd surface 37 is mounted on the said hotplate, and heats again as mentioned above. Thus, the wax (W) was melted. Thereby, the sintered compact 35 and the sub surface plate 31 were able to be isolate | separated. In addition, the wax W adhering to the sintered compact 35 and the sub surface plate 31 was removed by washing | cleaning etc.

Next, as shown to FIG. 6 (c), the 2nd surface 37 and the 1st surface 49 of the sintered compact 35 are reversed (that is, the 1st surface 49 is made upper), and the sintered compact 35 ), The second face 37 is disposed on the main surface plate 43.

In addition, the sintered compact 35 was arrange | positioned so that it might not shift | deviate on the main surface plate 43 by the frame 50 so that it might not move at the time of planar processing mentioned later. Specifically, the plastic frame 50 having the opening 50a corresponding to the outer shape of the sintered compact 35 is fixed to the surface 45 of the main surface plate 43, and the opening of the frame 50 is fixed. The sintered compact 35 was arrange | positioned on the main surface plate 43 by fitting the sintered compact 35 to 50a.

Next, as shown to FIG. 6 (d), it carried out similarly to the planar process of the 2nd surface 37 mentioned above, and performed the planar process of the 1st surface 49 of the sintered compact 35. By this planar processing, the plan view of the first surface 49 was processed to 5 µm or less.

In this way, the planar processing of both surfaces (ie, the first surface 49 and the second surface 37) of the sintered compact 35 is performed, so that the plan view of the first surface 49 and the second surface 37 is 5 μm. The pellicle frame 1 which has the following high top view was obtained.

(Step 10 P10)

Thereafter, the pellicle frame 1 may be chamfered. For example, you may perform R process so that the edge part of the pellicle frame 1 may become R radius of 0.03 mm-0.05 mm by brush polishing process.

By the above process, the pellicle frame 1 which has alumina as a main component was obtained. The Young's modulus and strength of the pellicle frame 1 were measured, and the Young's modulus was 420 GPa and the strength was 690 MPa.

1-4. effect]

(1) In the manufacturing method of the pellicle frame 1 of this 1st Embodiment, the sintered compact 35 used as the pellicle frame 1 is fixed to the sub surface plate 31, without deforming, and the sub surface plate 31 Since the flat surface of the 2nd surface 37 which is the surface on the opposite side to () is implemented, the flatness of the sintered compact 35 (thus the pellicle frame 1) can be raised.

Specifically, the sintered compact 35 is fixed to the sub surface plate 31 with wax W in a state in which the sintered compact 35 is not deformed (that is, in a state where the bad plan view is maintained when the plan view is bad). Therefore, even when the sintered compact 35 is pressurized by the grindstone 47 from the 2nd surface 37 side at the time of performing planar processing in order to improve flatness, the sintered compact 35 has the surface 33 of the sub surface plate 31. ) Deformation is unlikely to occur.

In this state, in the state where the sintered compact 35 is not elastically deformed, the planar processing on the side of the second surface 37 can be performed to improve the flatness, so that the sintered compact 35 (and thus the pellicle frame 1) It can be processed to have a small flatness.

In addition, in the first embodiment, as described above, the sintered compact 35 is subjected to planar processing on the second surface 37 side in a state in which the sintered compact 35 is not elastically deformed. The residual stress difference between the front and back surfaces can be reduced. Therefore, after planar processing, the sintered compact 35 can be suppressed from returning to original by its elasticity. Therefore, the sintered compact 35 (thus the pellicle frame 1) can hold the small flatness obtained by planar processing.

(2) Moreover, in this 1st Embodiment, after performing the planar process of the 2nd surface 37, the sintered compact 35 is isolate | separated from the sub surface plate 31, and the separated sintered compact 35 is 2nd surface. In the state where the 37 is mounted on the main surface plate 43, the surface processing is performed on the first surface 49.

That is, since the flatness of the 2nd surface 37 of the sintered compact 35 becomes small by the planar process with respect to the 2nd surface 37 mentioned above, let the 2nd surface 37 be the main surface plate 43 side, When the sintered compact 35 is mounted on the main surface plate 43 with a small flatness, the sintered compact 35 hardly deforms. Therefore, the flatness of the 1st surface 49 can also be made small by carrying out planar processing with respect to the 1st surface 49 of the sintered compact 35 which is hardly deformed.

Moreover, even if the difference of residual stress generate | occur | produced in the 2nd surface 37 side and the 1st surface 49 side of the sintered compact 35 by the planar process with respect to the 2nd surface 37 of the sintered compact 35, The state where the sintered compact 35 is placed on the main surface 43 with the second surface 37 side as the main surface plate 43 side (in other words, unlike the planar processing of the second surface 37, the sintered body 35 is In the state which is not fixed to the main surface plate 43, planar processing is performed with respect to the 1st surface 49. FIG. Therefore, the residual stress equivalent to the 2nd surface 37 can be given to the 1st surface 49 of the sintered compact 35, and the top view of the 1st surface 49 and the 2nd surface 37 of the sintered compact 35 Can be made small.

Thus, in this 1st Embodiment, the top view of both surfaces of the sintered compact 35 (thus the pellicle frame 1) in the thickness direction can be made small.

(3) In this 1st Embodiment, the sub surface plate 31 is an external dimension larger than the sintered compact 35 (thus the pellicle frame 1) in planar view. Therefore, since the whole sintered compact 35 can be arrange | positioned on the sub surface plate 31, fixing and planar processing of the sintered compact 35 are easy.

(4) In the first embodiment, since the Young's modulus of the sub surface plate 31 is 200 GPa or more and has high rigidity, the sub surface plate 31 is not deformed at the time of planar processing. Therefore, since the sintered compact 35 is hard to deform | transform during planar processing, the planar processing which improves the flatness of the sintered compact 35 can be performed suitably.

(5) In this 1st Embodiment, the top view of the surface 45, 33 (namely, upper surface) in which the sintered compact 35 of the main surface plate 43 (and the sub surface plate 31) is mounted is 3 micrometers or less, Preferably Preferably it is 1 micrometer or less. Therefore, when the sintered compact 35 is mounted on the main surface plate 43 (and the sub surface plate 31), the deformation of the sintered body 35 can be suppressed.

(6) In the pellicle frame 1 of the first embodiment, the difference in the residual stress between the upper surface 11 and the lower surface 13 of the pellicle frame 1 is 5 MPa or less, so that the pellicle frame 1 itself deforms. It is difficult to become, and the floor plan is small. Therefore, when the pellicle 5 is affixed on the surface of a photomask, since a photomask is hard to deform | transform, it is preferable.

(7) In the first embodiment, when the top surface 11 and the bottom surface 13 of the pellicle frame 1 are 5 µm or less, when the pellicle 5 is affixed to the surface of the photomask, It is preferable because the photo mask is hardly deformed.

[1-5. Word correspondence]

The sintered compact 35, the 1st surface 49, the 2nd surface 37, the sub surface plate 31, the main surface plate 43, and the fixing material W of the pellicle frame 1 of 1st Embodiment are respectively seen It corresponds to an example of a pellicle frame of a start, a 1st surface, a 2nd surface, a base, and a fixing material.

[2. 2nd Embodiment]

Next, although 2nd Embodiment is described, about the content similar to 1st Embodiment, the description is abbreviate | omitted or simplified. In addition, the same number is attached | subjected to the structure similar to 1st Embodiment.

In this 2nd Embodiment, as shown in FIG. 7, the sintered compact 35 is arrange | positioned directly on the surface plate 43 of the planar processing machine 41, and the sintered compact 35 is used with the wax W. It is fixed to the 43 and the planar process of the 2nd surface 37 of the sintered compact 35 is performed. In addition, in FIG. 7, the shape of each member, such as the sintered compact 35, is shown typically, highlighting characteristics.

In other words, in the second embodiment, the sintered compact 35 is directly fixed to the surface plate 43 of the planar processing machine 41 without using the ceramic sub surface plate of the first embodiment.

Moreover, when inverting the sintered compact 35 and performing the planar processing of the 1st surface 49, the sintered compact 35 is platen 43 using the frame body (not shown) used in 1st Embodiment. Fix it to

Moreover, the manufacturing process similar to 1st Embodiment can be employ | adopted basically except the content which fixes the sintered compact 35 directly to the surface plate 43. In addition, the wax (W) can be melted and removed by, for example, adding warm air.

This second embodiment exhibits the same effects as the first embodiment.

[3. Experimental Example]

Next, the experimental example performed in order to confirm the effect of this indication is demonstrated.

<Experimental example 1>

In this Experimental Example 1, when manufacturing the pellicle frame (hence the sintered compact) of the example within the scope of the present disclosure in the same manner as in the first embodiment, as described later, plan views of the first and second surfaces of the sintered compact Was measured.

Moreover, the processing conditions at the time of planar processing by a planar processing machine are as follows.

Type of grindstone: diamond grindstone ＃ 1500

Processing time  About 3 minutes

Processing condition  : Finishing grinding after rough grinding

              Rough grinding (processing speed: 0.4 ㎛ / sec)

              Finishing Grinding (Machining Speed: 0.2 ㎛ / sec)

First, the flatness of the 1st surface and the 2nd surface was measured about the sintered compact before planar processing after the said 8th process.

Next, after the process of the 2nd surface, the sintered compact was isolate | separated from the surface plate (sub surface plate), and the top view of the 1st surface and the 2nd surface of this sintered compact was measured.

Next, after inverting the sintered compact and planar processing of the first surface thereof, plan views of the first surface and the second surface were measured.

In addition, a sintered compact of a comparative example outside the scope of the present disclosure was produced, and in the same manner as in the above example, the first surface and the first surface before and after the plane processing of the second surface and after the plane processing of the first surface, respectively The top view of two sides was measured.

Moreover, in this comparative example, in the ninth process mentioned above, when carrying out the planar process of the 2nd surface in a sintered compact, the sintered compact on a main surface plate is not implemented, without performing the fixing process which fixes a 1st surface to a sub surface plate. Was carried out similarly to the said Example except having arrange | positioned simply and performing planar processing.

The results are shown in Tables 1 and 2 below.

As shown in Table 1, in the Example which performed the fixing process and performed the planar process with respect to the 2nd surface, while the top view of the 2nd surface before planar processing was 27.1 micrometers, it became 16.8 micrometers after planar processing. On the other hand, in the comparative example which performed planar processing without performing a fixing process, while the flatness of the 2nd surface before planar processing was 27.9 micrometers, it was 21.4 micrometers after planar processing.

These results show that the flatness is improved when the fixing step is performed and the planar processing is performed as in the example.

In addition, Table 2 has shown the result of having performed surface processing with respect to the 1st surface of the sintered compact in an Example and a comparative example.

As shown in this Table 2, when the surface processing is performed on the first surface of the sintered body after the surface processing on the second surface, in the embodiment, the plan view of the first surface is 1.3 µm, and the plan view of the second surface is Was 1.5 µm. On the other hand, in the comparative example, the top view of the 1st surface was 20.7 micrometers and the top view of the 2nd surface was 21.4 micrometers.

From the above results, after performing a fixing process and performing a planar processing on the second surface of the sintered compact, the embodiment in which a planar processing was performed on the first surface is only performed after the planar processing is performed on the second surface. Compared with the comparative example which performed the planar processing with respect to one surface, it turns out that a plan view can be improved further on both a 1st surface and a 2nd surface.

In addition, in the comparative example, the result which confirmed the influence on a top view by performing planar processing further on a 1st surface and a 2nd surface, and repeating planar processing is shown in following Table 3.

In the comparative example which performs planar processing, without performing a fixing process with respect to a 2nd surface, as shown in Table 3, even if planar processing is repeated, a flatness does not improve significantly and the improvement of a flatness could not be confirmed.

As can be seen from the above Tables 1 to 3, in the examples, the flatness of the second surface was improved after the planar processing of the second surface, which was preferable than that of the comparative example. Moreover, after planar processing of the 2nd surface and the 1st surface, the top view of both the 2nd surface and the 1st surface was small to 1.5 micrometers or less, and it was further more preferable.

<Experiment 2>

In this Experimental Example 2, the state of warpage when the pellicle frame was loaded was examined.

As shown in FIG. 8, the pair of ceramic blocks 53 were arrange | positioned on the alumina base plate 51, and the pellicle frame 55 similar to 1st Embodiment was arrange | positioned on the ceramic block.

Moreover, the dimension of a pellicle frame is 149.0 mm in long sides, 115 mm in short sides, 2.0 mm in width, and 2.5 mm in thickness.

And the height in each position (namely, the center part of a long side, the edge part on a ceramic block) of the upper surface of a pellicle frame was measured from the upper surface of a ceramic block using the dial gauge. Moreover, the stylus load of the dial gauge is 180 gw.

As a result, it was found that the height of the center of the long side of the pellicle frame was 2.430 mm and the height of the end was 2.499 mm, and the center of the long side of the pellicle frame was slightly bent downward from the end.

In short, it was confirmed that the central portion of the long side of the pellicle frame was bent about 70 µm by the stylus load (180 gw) of the dial gauge.

<Experiment 3>

This Experimental Example 3 investigates the relationship between the stress and deformation (deformation warpage amount) during plane processing of the pellicle frame by calculation.

By Experimental Example 2, it was confirmed that the central portion of the pellicle frame was bent at about 70 µm at the styling load (180 gw) of the dial gauge.

Therefore, when three-point bending tensile stress (sigma) equivalent to 180 gw (= 1.76 N) is calculated, sigma = 64.7 N / mm 2 = 64.7 MPa.

Σ = 3PL / 2ab ^{2 =} (3 * 1.76 * 149) / (2 * 2 * 2.5 * 2.5) = 31.5 N / mm2

(P: bending load, L: distance between points, a: test piece width, b: test piece height)

Here, when a tensile stress of 31.5 MPa is applied to the lower surface and a compressive stress of 31.5 MPa is applied to the upper surface, the stress difference between the lower surface and the upper surface as the front and rear surfaces is 63.0 MPa, and deformation (curvature) of 70 µm occurs.

For materials with a Young's modulus of 400 GPa

10 µm warpage stress difference = 9.0 MPa

5 µm warpage stress difference = 4.5 MPa

Therefore, in order to realize the flatness of 5 micrometers or less, it can be considered that the stress difference between the front and back surfaces should be 5 MPa or less due to elastic deformation during processing.

[4. Other embodiments]

In addition, this indication is not limited to the said embodiment at all, It goes without saying that various forms can be employ | adopted as long as it belongs to the technical scope of this indication.

(1) As a material of a pellicle frame, a cemented carbide, cermet, a single metal, an alloy metal, etc. can be employ | adopted besides the material which consists of ceramics, or the material which has a ceramic as a main component.

(2) As the fixing material, a liquid bonding material (that is, an adhesive) or the like can be used in addition to the wax. Moreover, the solidified adhesive agent can be removed using the solvent etc. which can melt | dissolve an adhesive agent, for example.

(3) In the case of using a material (for example, wax) that is melted by heating as a fixing material, for example, the upper and lower surfaces of the base (for example, a surface plate such as a sub surface plate) when the wax is cooled and solidified. The temperature difference is preferably small (for example, 1 ° C. or less) in order to suppress warping of the surface plate according to the temperature difference.

In addition, in order to suppress the curvature of the surface plate according to a temperature difference, although cooling can be considered, it is preferable to use a high thermal conductivity and a low thermal expansion material. For example, aluminum nitride, silicon carbide, silicon nitride and the like are preferable.

(4) For the pellicle frame having a poor flatness (for example, 50 μm or more), the flatness of the first and second surfaces, shown in the first embodiment, may be repeated two or more times, for example, to improve the flatness. Can be.

(5) As a surface plate, you may use a single surface plate or a combination of a plurality of surface plates. For example, you may mount a sintered compact on a single surface plate and perform a surface process. In addition, an auxiliary sub surface plate may be provided on the main surface plate serving as a base, and the sintered body may be placed on the sub surface plate to perform planar processing.

(6) The surface plate used by the mounting process which processes a 1st surface may be the same surface plate as the surface plate used by the fixed processing process which processes a 2nd surface, or may be a different surface plate.

(7) Moreover, as a ceramic material which forms the frame of a pellicle frame, various materials, such as a composite ceramic of silicon nitride, zirconia, alumina, and titanium carbide, as disclosed, for example, in Unexamined-Japanese-Patent No. 2016-122091, are mentioned. Can be adopted.

(8) In addition, the function of one component in each of the above embodiments may be shared among the plurality of components, or the function of the plurality of components may be exerted on one component. In addition, you may abbreviate | omit a part of structure of each said embodiment. In addition, you may add and replace at least one part of the structure of each said embodiment with respect to the structure of another embodiment. In addition, all the aspects included in the technical idea specified from the language of the claim are embodiments of the present disclosure.

One… Pellicle frame
5... Pellicle
31, 43... Plate
35... Sintered body
37... 2nd side
41... Plane processing machine
49... First side

Claims (17)

A pellicle frame having a frame shape having a first surface and a second surface formed on both sides in the thickness direction, and an inner circumferential surface and an outer circumferential surface that are in contact with the first surface and the second surface in contact with each other, is placed on a base of the pellicle frame. In the manufacturing method of a pellicle frame which processes,
A fixing step of fixing the pellicle frame to the base while keeping the first surface on the base side and maintaining the shape of the pellicle frame;
The manufacturing method of the pellicle frame which has a fixed process process of performing planar processing with respect to the said 2nd surface of the said pellicle frame fixed to the said base material. The method of claim 1,
A separation step of separating the pellicle frame from the base after the planar processing;
The manufacturing method of the pellicle frame which has the mounting process of performing the planar process with respect to the said 1st surface, in the state which mounted | separated the said pellicle frame to the said base side by making the said 2nd surface into the said base side. The method of claim 2,
And after performing the fixing step, the fixing step, the separation step, and the tact step, the fixing step, the fixing step, the separation step, and the tact step again. The method of claim 2 or 3,
The base used in the said mounting process is the same base as the base used by the said fixed process, or a different base. The method according to any one of claims 1 to 3,
The manufacturing method of the pellicle frame using what combined the single foundation or multiple foundations based on the said foundation. The method according to any one of claims 1 to 3,
The foundation has a dimension in plan view that is larger than an external dimension of the pellicle frame. The method according to any one of claims 1 to 3,
The said base has a characteristic which does not deform | transform at the time of planar processing, The manufacturing method of the pellicle frame. The method according to any one of claims 1 to 3,
The Young's modulus of the said foundation is 200 GPa or more, The manufacturing method of the pellicle frame. The method according to any one of claims 1 to 3,
In the fixing step, the pellicle frame is fixed by the fixing member disposed between the base and the pellicle frame. The method of claim 9,
When the said pellicle frame is removed from the said foundation after the said planar process, the said pellicle frame is isolate | separated by removing the said fixing material between the said base and the said pellicle frame. The method of claim 10,
In the fixing step, after the base member and the pellicle frame are filled with a fixing material in a non-solidified state, the fixing material is solidified to fix the pellicle frame. The method of claim 11,
The fixing material is a liquid bonding material, and the liquid bonding material is filled between the base and the pellicle frame, and then solidified to perform the fixing. The method of claim 11,
The fixing material is a wax, and the wax in a solid state is heated to liquefy, filled between the base and the pellicle frame, and then cooled to solidify the wax to perform the fixing. . The method according to any one of claims 1 to 3 and 10 to 13,
The manufacturing method of the pellicle frame whose plan view of the surface on which the said pellicle frame is mounted is 3 micrometers or less. The method according to any one of claims 1 to 3 and 10 to 13,
The said pellicle frame has a ceramic as a main component, The manufacturing method of a pellicle frame. In a pellicle frame having a first surface and a second surface formed on both sides in the thickness direction, and an inner circumferential surface and an outer circumferential surface in contact with the first and second surfaces,
A pellicle frame, wherein a difference in residual stress between the first surface and the second surface of the pellicle frame is 5 MPa or less. In a pellicle frame having a first surface and a second surface formed on both sides in the thickness direction, and an inner circumferential surface and an outer circumferential surface in contact with the first and second surfaces,
A pellicle frame having a plan view of the first and second surfaces of the pellicle frame of 5 µm or less.

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