HK1180398B - Manufacturing method of dust-proof film assembly for lithography - Google Patents

Description

Method for manufacturing dustproof film assembly for photoetching

Technical Field

The present invention relates to a photomask adhesive for a pellicle for lithography, and further relates to a shape of the pellicle adhesive.

Background

In semiconductor manufacturing such as LSI and super LSI, or in manufacturing liquid crystal display panels, a semiconductor wafer or a liquid crystal is irradiated with light to form a pattern. In the exposure original plate (photomask for lithography) used in the above-described case, dust adheres to the dust, and the dust absorbs light to bend the light, which not only deforms the transferred pattern and causes uneven edges, but also blackens the base, and causes problems such as deterioration in size, quality, appearance, and functions of the completed member.

Therefore, the above-described operation is usually performed in a clean room, but it is difficult to keep the exposure original plate clean even in the clean room, and therefore, a method of attaching a pellicle for blocking dust and allowing exposure light to pass through well to the surface of the exposure original plate is generally adopted. In this case, dust is not directly attached to the surface of the exposure original plate, but is attached to the pellicle film, and thus, if the pattern of the exposure original plate is brought into focus during photolithography, the dust on the pellicle film is irrelevant to the transfer.

The basic construction of the pellicle assembly is shown in figures 1 and 2. A transparent dustproof thin film 3 composed of nitrocellulose, cellulose acetate, fluorine-based polymer and the like which transmits exposure light well is adhered to a dustproof thin film module frame 1 formed by aluminum alloy such as A7075, A6061, A5052 and the like, stainless steel, polyethylene and the like which is subjected to black oxide film treatment, or an upper end of the dustproof thin film module frame 1 and the like which is coated and painted on aluminum and other metals, a good solvent of the dustproof thin film is painted and painted, and then the dustproof thin film module frame is adhered after air drying (patent document 1), or the dustproof thin film module frame is adhered by an adhesive 2 such as acrylic resin, epoxy resin and fluorine resin (patent document 2, patent document 3), furthermore, polybutylene, polyvinyl acetate, fluorine-based polymer and the like are used for installing an exposure original plate at a lower end of the dustproof thin film module frame 1, An adhesive layer 4 made of acrylic resin or silicone resin, and a photomask adhesive protective liner 5 for protecting the adhesive layer.

[ Prior Art document ]

[ patent document ]

[ patent document 1 ] Japanese patent application laid-open No. Sho 58-219023

[ patent document 2 ] specification of U.S. Pat. No. 4861402

[ patent document 3 ] Japanese patent publication No. Sho 63-27707

The pellicle is provided so as to surround a pattern region formed on the surface of the photomask substrate. The pellicle is provided to prevent dust from adhering to the photomask substrate, and therefore the pattern region is separated from the outside of the pellicle, so that dust outside the pellicle does not adhere to the pattern surface. In recent years, the design rule of LSI is advancing to a finer design than a quarter, and the exposure source is advancing to a shorter wavelength. That is, g-line (436 nm) and I-line (35 nm) of mercury lamps, which have been the mainstream from the past, are KrF excimer laser (248 nm), ArF excimer laser (193 nm), F2 laser (157 nm), and the like.

As the exposure is made shorter, the energy required for exposure increases. When light of high energy is used, the possibility that a reaction product is generated on the photomask substrate due to the reaction of gaseous substances present in the exposure atmosphere as compared with light of a conventional wavelength is significantly increased. Therefore, measures such as reducing the gas state material in the clean room as much as possible, strictly cleaning the photomask, and eliminating the problem of generating gas from the constituent material of the pellicle are taken.

In particular, when the pellicle is used by directly adhering to a photomask substrate, it is required that the amount of gas generated from the constituent material of the pellicle, that is, the photomask adhesive, the pellicle film adhesive, the inner wall coating agent and the like formed from an organic material is small and the improvement can be achieved. However, the cloud-like foreign matter, so-called "haze", generated on the photomask substrate cannot be completely eliminated even if the photomask is cleaned and the constituent material of the pellicle is gasified with less generation, which causes a reduction in yield in semiconductor manufacturing.

On the other hand, in recent years, the field of patterns formed on a photomask has been widened, and since photolithography is performed by efficiently using the photomask surface, light is irradiated to the vicinity of the pellicle film assembly during exposure. Thus, when the photomask adhesive of the pellicle is expanded inward from the frame of the pellicle during exposure, gas is generated when exposure light and/or scattered light thereof hits the photomask adhesive, and the generated gas such as ozone thermally damages the photomask adhesive, which may deteriorate the function of the photomask adhesive.

Even if the occurrence of gassing of the photomask adhesive is reduced, if the critical photomask adhesive swells, the improvement is not useful, and in some cases, the photomask is damaged and largely damaged.

The reason why such a problem occurs is that the pellicle is attached to the photomask by applying a high pressure thereto. This is because the pellicle is attached to the photomask through the photomask adhesive, and if a sufficient load is not applied, a gas passage is formed between the photomask and the photomask adhesive, and thus the original function of isolating the pattern surface of the photomask from the external environment may be lost.

When such a high adhesion pressure is applied, the photomask adhesive is significantly deformed when pressed, and thus the photomask adhesive bulges out inside the frame.

The present invention has been made in view of the above circumstances. The invention provides a pellicle for lithography with a shape of a photomask adhesive adjusted, and a method for manufacturing the pellicle. According to this method, when the pellicle is attached to the photomask, the photomask adhesive does not bulge out to the inside of the pellicle even when pressure is applied.

Disclosure of Invention

The above object of the present invention can be achieved by the following technical means.

A pellicle for lithography comprising a pellicle film (3) (see fig. 1), a pellicle frame (1) for placing the pellicle film in tension, an adhesive layer (2) for pellicle film adhesion formed on one end face of the pellicle frame, and a photomask adhesive layer (4) formed on the end face opposite to the adhesive layer for pellicle film adhesion, characterized in that:

the cross section of the photomask adhesive layer (4) is rectangular or trapezoidal, the upper end of the photomask adhesive layer is provided with a flat surface, and the angle alpha between the side surface of the photomask adhesive layer and the frame surface is less than or equal to 90 degrees.

The angle formed by the side surface of the adhesive layer and the frame surface in the present invention is referred to as a bottom angle of a trapezoid in the cross-sectional shape of the adhesive layer, as exemplified in fig. 3, and is also referred to as a side wall surface angle. The reason why the cross-sectional shape of the adhesive layer is trapezoidal will be described later with reference to fig. 6.

In the present invention, the cross-sectional shape of the rectangle or trapezoid is not required to be geometrically strict trapezoid or rectangle, and may be a shape similar to a trapezoid or a rectangle.

For easy comparison with the drawings, the drawings are described in parentheses with reference to symbols, but the configuration of the present invention is not limited to the drawings.

[ Effect of the invention ]

The photomask adhesive formed at one end of the dustproof pellicle frame is formed in a shape such that the angle between the side wall surface and the frame surface is 90 DEG or less, thereby preventing the photomask adhesive from bulging from the dustproof pellicle frame, minimizing exposure to exposure light or scattered light thereof in a photolithography process, and preventing the generation of gas which causes fogging and the deterioration of the photomask adhesive.

Drawings

Fig. 1 is a cross-sectional explanatory view showing a basic structure of the pellicle.

FIG. 2 is a perspective view illustrating a basic structure of the pellicle.

FIG. 3 is a schematic illustration showing an angle α between a photomask adhesive layer and a sidewall surface formed on a pellicle frame.

FIG. 4 is a graph of the preferred relationship between the width of the upper end surface of the pellicle frame and the angle of the sidewall surface of the photomask adhesive layer.

Fig. 5 is a graph showing a relationship between the width of the upper end surface of the pellicle frame and the amount of the photomask adhesive applied.

FIG. 6 is a schematic diagram illustrating the subsequent formation of a photomask with an adhesive material.

Detailed Description

As a result of studies, the present inventors have found that an angle formed between a side wall surface of an adhesive and a frame surface is 90 ° or less when an adhesive layer is formed, whereby bulging at the time of pressure-bonding a dust-proof film assembly can be prevented, and have completed the present invention.

The invention is mainly characterized in that the angle formed by the side wall surface of the photomask adhesive layer of the dustproof pellicle assembly and the frame surface is less than or equal to 90 degrees, thereby preventing various problems caused by the expansion of the photomask adhesive when the dustproof pellicle assembly is adhered on a photomask.

If only the prevention of swelling of the photomask adhesive is aimed at, the smaller the angle between the side wall surface and the frame surface is, the better, but the smaller the angle is, the adhesion strength is deteriorated. Therefore, the configuration in which the condition "90 ° or less" is such that sufficient adhesion strength can be obtained within the range where there is no risk of bulging makes the present invention novel and inventive.

The present invention will be described in further detail below with reference to the accompanying drawings.

In the dustproof pellicle of the present invention, as shown in fig. 1, a dustproof pellicle 3 is stretched over an upper end surface of a dustproof pellicle frame 1 via a dustproof pellicle-adhering adhesive layer 2, and in this case, a photomask-adhering adhesive (photomask adhesive) layer 4 is usually formed on a lower end surface, and a backing layer 5 is detachably attached to a lower end surface of the photomask-adhering adhesive layer 4. In addition, the corners of the upper and lower end faces of the pellicle frame are preferably chamfered. The size of the surface formed by chamfering (hereinafter referred to as "C surface") is 0.2 to 0.4 mm.

The size of these components of the pellicle is the same as that of a general pellicle, for example, a pellicle for semiconductor lithography, a pellicle for large-scale liquid crystal display panel manufacturing lithography, and the like, and the above-mentioned known materials may be used as the material.

As described above in more detail, the kind of the dust-proof film is not particularly limited, and for example, amorphous fluoropolymer or the like which has been used in the prior art with excimer laser can be used. Examples of the amorphous fluoropolymer include CYTOP (trade name manufactured by asahi glass, Ltd.), teflon AF (trade name manufactured by dupont, Ltd.).

These polymers may be dissolved in a solvent and used as necessary in the production of the dustproof film, and for example, a fluorine-based solvent or the like is suitable for dissolution.

As the base material of the pellicle frame used in the present invention, conventionally used aluminum alloy materials can be used, and preferably JIS A7075, JIS A6061, JIS A5052 and the like are used. The resin, glass, or the like other than the aluminum alloy material is not particularly limited as long as the strength of the pellicle frame can be ensured.

Vent holes (not shown) may be formed in all of 4 sides of the pellicle frame. The size and shape of the air vent are not particularly limited, and may be appropriately selected depending on the dust filtration size, filtration area, or ventilation amount of the dust removal filter provided in the air vent.

The filter for removing dust used in the present invention is not particularly limited in shape, number, and location as long as it can be provided in the vent part. Examples of the material of the filter for dust removal include resin (P TFE, nylon 66, etc.), metal (316L stainless steel, etc.), ceramics (alumina, aluminum nitride, etc.), etc.

The outer part of the dust removing filter is preferably a chemical filter having a function of adsorbing and decomposing chemical substances in the environment.

As the adhesive for bonding a dustproof film, conventionally used ones can be used, for example, fluoropolymers such as acrylic resin adhesive, epoxy resin adhesive, silicone resin adhesive, fluorine-containing silicone resin adhesive, and the like, and among them, fluorine-based polymers are preferable.

Specific examples of the fluorine-based polymer include a fluorine-based high polymer CTX 809 (trade name, manufactured by asahi glass corporation).

Examples of the adhesive for photomask adhesion include silicone resin adhesives, acrylic adhesives, and hot-melt adhesives such as SEBS (polystyrene-poly (ethylene-butylene) -polystyrene). The adhesive is not particularly limited as long as it has an appropriate adhesive strength and causes no problem of gas generation during exposure.

These adhesive layers are applied to one end face of the frame, and then the opposite side to the end face of the frame is subjected to a flat surface forming process. The method is to press the adhesive after coating to form the adhesive. Specifically, the adhesive solution is discharged from a discharge nozzle, a bead is formed at the tip of the nozzle, the discharge nozzle is brought into contact with the end face of the frame, and the nozzle is moved along the frame. After the adhesive is uniformly applied to the entire periphery of the frame, in the case of a thermosetting adhesive, heat treatment is performed, and the surface of the adhesive is pressed to perform planarization treatment at the time of semi-curing.

In the case of a hot-melt adhesive, the adhesive is applied and cured, and then flattened by heating and pressing.

FIG. 3 is a schematic view showing a cross-sectional shape of an adhesive material for a photomask used for bonding to a frame of a pellicle.

(A) In the case where the side wall surface angle (described below) is 90 °.

(B) In the case where the side wall surface angle is 60 °.

(C) In the case where the side wall surface angle is 45 °.

For convenience of reading, the upper and lower sides are reversed, unlike the above-described fig. 1.

The side wall angle (angle between the side surface of the photomask adhesive layer and the frame surface) α can be changed depending on the amount of adhesive applied.

FIG. 4 is a diagram showing the relationship between the upper end face width and the side wall face angle in the cross-sectional shape of the photomask adhesive layer,

fig. 5 is an exemplary graph of the relationship between the upper end face width and the coating volume.

Fig. 6 is a schematic view showing the relationship between the amount of adhesive and the side wall surface angle α in the case of forming the photomask adhesive layer.

(upper part of the figure) the photomask adhesive 4 is applied on the lower end face of the dustproof pellicle assembly frame 1.

(A1) In the case where the amount of the adhesive material is relatively large.

(C1) In the case where the amount of the adhesive material is relatively small.

(B1) In the case where the amount of the adhesive material is in the middle of the above two.

The thickness of the adhesive layer for photomask adhesion was set to a predetermined value (0.4 mm in this example).

The photomask adhesive 4 coated on the lower end surface of the pellicle frame 1 (see reference a 1) was made to have a thickness of 0.4 mm as shown in (a 2) by being pressed downward against the molding jig surface P.

The cross-sectional shape of the formed adhesive layer 4 is almost trapezoidal.

The illustrated angle α corresponds to the side wall surface angle, which in this example (a 2) is about 60 °.

FIG. 6A 2 corresponds to FIG. 3B

As shown in fig. 6 (C1), if the amount of the adhesive is too small, the side wall surface angle α formed as shown in (C2) becomes small.

As shown in fig. 6 (B1), the amount of the adhesive material was medium, and the side wall surface angle α formed as in (B2) was medium.

This (B2) corresponds almost to the above-described fig. 3 (C).

The pellicle of the present invention is manufactured by placing a pellicle film under tension on the upper end surface of a pellicle frame by a usual method through an adhesive layer for pellicle film attachment, and forming an adhesive layer for photomask attachment on the lower end surface of the pellicle frame, and then providing a release layer (liner layer) on the lower end surface of the adhesive layer for photomask attachment so as to be peelable. The adhesive layer for sticking a pellicle formed on the upper end face of the pellicle frame is diluted with a solvent as necessary, applied to the upper end face of the pellicle frame, and then heated, dried and cured. In this case, the method of applying the adhesive is brush coating, spray coating, automatic liquid dispenser coating, or the like.

The material of the adhesive-protective underlayer for photomask adhesion used in the present invention is not particularly limited. For example, PET, PTFE, PFA, PE, PC, dichloroethane, PP, etc. may be used.

[ example 1 ]

Hereinafter, the following description will be made of the example pairs (4 examples) and the comparative examples (3 examples).

In 7 examples, a photomask adhesive layer was formed on a pellicle frame of the same size, the photomask adhesive layer was attached to a photomask substrate of the same size, exposure irradiation was performed under the same conditions, and then the presence or absence of foreign matter generation was examined, and in each example, "the angle α between the side surface of the adhesive layer and the frame surface" was changed.

The main operating conditions and the inspection results in example (4) and comparative example (3) are shown in table 1.

[ example 1 ]

First, as a pellicle frame, a pellicle frame having an outer frame dimension of 149 mm × 122 mm × 5.8 mm, a frame thickness of 2 mm, and a C-plane dimension of both end surfaces of C: 0.2 mmA 7075-T651. And a vent hole with the diameter of 0.5 mm is arranged at the center 1 of one side surface of the frame.

The frame was cleaned on the surface, and then the frame was washed with glass beads at a discharge pressure of about 147 kPa (1.5 kg/cm)²) The sandblast apparatus of (1) was subjected to surface treatment for 1 minute to roughen the surface. The frame was then washed in an NaOH treatment bath for 10 seconds, and then anodized at a liquid temperature of 18 ℃ in a 14% sulfuric acid aqueous solution at a formation voltage of 10V (1.3A).

Then, black dyeing and hole sealing treatment are performed to form a black oxide film on the surface. Thereafter, the washing was performed for 5 minutes using ultrapure water and an ultrasonic washing apparatus.

Subsequently, the inner surface of the frame was coated with an acrylic pressure-sensitive adhesive by 10 μm using a spray coating apparatus.

Then, a filter with a material of PTFE, a dust filtration size of 0.1 μm to 3.0 μm, a filtration capacity of 99.9999%, a width of 8 mm, a height of 2.5 mm and a thickness of 300 μm was provided in the vent. The filter includes a chemical filter in the filter portion for removing dust and the outer side.

Then, teflon AF 1600 (trade name, manufactured by dupont, usa) was dissolved in a fluorine-based solvent fluoride FC-75 (trade name, manufactured by 3M, usa) to prepare a solution having a concentration of 8%.

Then, a transparent film having a thickness of 0.83 μm was formed from the solution on a mirror-polished silicone substrate surface having a diameter of 250 mm and a thickness of 600 μm by a spin coater.

Then, a frame having an outer dimension of 200 mm × 200 mm × 5 mm in width and a thickness of 5 mm was attached to the film using Aralditerapid (trade name manufactured by Showa polymer Co., Ltd.) and peeled off from the substrate surface.

Next, an acrylic pressure-sensitive adhesive was applied to one end surface of the thus prepared aluminum alloy frame.

In this case, when the coating amount is increased, the side wall surface angle is increased, and when the coating amount is decreased, the side wall surface angle is decreased, whereby the side wall surface angle is controlled. The coating amount was set so that the adhesive layer thickness was 0.4 mm, the end face width was 1.4 mm, and the side wall face angle was 45 ° (coating volume ratio: 10.94).

The frame was heated at 100 ℃ for 3 minutes to effect precuring. The surface of the adhesive was flattened by pressing with a pressing device having a pressing plate capable of forming a semi-cured adhesive layer with a surface flatness of 10 μm, and the side wall surface angle of the adhesive layer of the obtained adhesive was 45 ° and the end surface width was 1.4 mm. (column references of example 1 in Table 1)

On the other end face of the aluminum alloy frame, a fluorine-based solvent CTSOLVE 180 (trade name, manufactured by asahi glass (ltd.)) diluted fluorine-based high polymer CTX 809 (trade name, manufactured by asahi glass (ltd.)) was applied, and the resultant was heated at 100 ℃ for 10 minutes, dried and cured. Then, a PET liner was prepared separately and bonded to a photomask adhesive by a liner bonding apparatus equipped with a CCD camera image processing position determining mechanism.

Next, after the film was adhered to the surface of the prepared teflon AF 1600 (described above), the frame was heated with an IR lamp to fuse the frame and the film.

The two frames are fixed by a fixing jig with the attachment surface of the pellicle frame facing upward, without shifting the relative positions of the frames. Then, the frame outside the pellicle frame was pulled up and fixed, and a tension of about 0.5N/m (0.5 g/cm) was applied to the film portion outside the pellicle frame.

Then, while dropping a fluorine-based solvent fluoride FC 75 (trade name, manufactured by dupont) at a rate of 10 μ l per minute, an unnecessary film portion outside the pellicle frame was cut off by moving a knife attached to the SCARA robot along the peripheral portion of the adhesive portion of the pellicle frame by a tube liquid dispenser.

The completed pellicle was washed so that the concentration of the acid component remaining on the surface was 1 ppb or less, and was attached to a 6-inch photomask substrate made of quartz glass on which a Cr test pattern was formed.

Next, the frame was mounted on an ArF excimer laser scanner NSR S306C (trade name, Nikon, Inc.) and exposed to light at an intensity of 0.01 mJ/cm on the photomask surface²Pulse, repetition frequency 4000 Hz, irradiation was carried out until 500J/cm was reached²The irradiation amount of (3).

On the irradiated 6-inch photomask, the haze (haze) and foreign matter were not observed in the test pattern portion and the glass portion when observed with a laser foreign matter inspection apparatus.

[ example 2 ]

First, as a pellicle frame, a pellicle frame having an outer frame dimension of 149 mm × 122 mm × 5.8 mm, a frame thickness of 2 mm, and a C-plane dimension of both end surfaces of C: 0.2 mm A7075-T651 aluminum alloy frame. And a vent hole with the diameter of 0.5 mm is arranged at one center of one side surface of the frame.

The frame and the surface were washed, and then the frame and the surface were subjected to a discharge pressure of about 147 kPa (1.5 kg/cm) using glass beads²) The surface was roughened by performing the surface treatment for 1 minute in the sandblasting apparatus of (1). Then, the frame was subjected to a washing treatment in an NaOH treatment bath for 10 seconds, and then anodized at a formation voltage of 10V (1.3A), a 14% sulfuric acid aqueous solution and a liquid temperature of 18 ℃.

Subsequently, black dyeing and sealing treatment were performed to form a black oxide film on the surface. Thereafter, the washing with ultrapure water and the ultrasonic washing apparatus was performed for 5 minutes at the same time.

Next, a spray coating apparatus was used to coat the inner surface of the frame with a silicone adhesive: KR-3700 (trade name, manufactured by shin-Etsu chemical Co., Ltd.) was coated to a thickness of 10 μm.

Then, a filter with the material of PTFE, the dust filtering size of 0.1-3.0 μm, the filtering capacity of 99.9999%, the width of 8 mm, the height of 2.5 mm and the thickness of 300 μm is arranged at the vent. The filter has a structure having a filter unit for removing dust and the chemical filter on the outer side.

Then, teflon AF 1600 (trade name, manufactured by DuPont, U.S.A.) was dissolved in a fluorine-based solvent, fluorinert FC-75 (trade name, manufactured by 3M, U.S.A.) to prepare a 8% solution.

Then, a transparent film having a film thickness of 0.83 μm was formed from the solution by a spin coater on a surface of a mirror-polished silicone substrate having a diameter of 250 mm and a thickness of 600 μm.

Then, a frame having an outer dimension of 200 mm × 200 mm × 5 mm in width and a thickness of 5 mm was attached to the film with an epoxy adhesive, Aralditerapid (product name, manufactured by Showa polymer Co., Ltd.), and peeled off from the substrate surface.

Next, one end face of the aluminum alloy frame prepared as described above was coated with a silicone adhesive: KR-3700 (trade name, manufactured by shin-Etsu chemical Co., Ltd.). The coating amount was set (coating volume ratio: 0.96) so that the adhesive layer thickness was 0.4 mm, the end face width was 1.49 mm, and the side wall face angle was 60 °.

The frame was heated at 100 ℃ for 3 minutes to effect precuring. The surface flatness of the semi-cured adhesive layer was set to 10 μm, and the surface was pressed by a pressing device having a pressing plate on which a release layer was formed, so that the adhesive surface was formed flat.

The side wall surface angle of the obtained adhesive layer was 60 °, and the end surface width was 1.49 mm.

On the other end face of the aluminum alloy frame, a fluorine-based polymer CTX (trade name, manufactured by asahi glass corporation) diluted with a fluorine-based solvent ctsolvate 180 (trade name, manufactured by asahi glass corporation) was applied, and the resultant was dried and cured at 100 ℃ for 10 minutes. Then, a separately prepared PET liner was attached to the photomask adhesive by a liner attaching apparatus having a CCD camera image processing position determining mechanism.

Subsequently, the film was adhered to the surface of the prepared teflon AF 1600 (described above), and then the frame was heated with an IR lamp to fuse the frame and the film.

The two frames are mounted on a fixing jig with the attachment surface of the pellicle frame facing upward, and fixed so that the relative positions thereof do not deviate. Then, the frame outside the pellicle frame was pulled up and fixed, and a tension of 0.5N/m (/ cm) was applied to the film portion outside the pellicle frame.

Next, a fluorine-based solvent fluorinert FC 75 (trade name, manufactured by dupont) was dropped at a rate of 10 μ l per minute into the tube type liquid dispenser, and a knife attached to the SCARA robot was moved along the periphery of the adhesive portion of the pellicle frame to cut off the unnecessary film portion outside the pellicle frame.

The completed pellicle was attached to a 6-inch photomask substrate made of quartz glass and having a Cr test pattern formed thereon, which was cleaned under conditions in which the concentration of the acid component remaining on the surface was 1 ppb or less.

The frame was then mounted on an ArF excimer laser scanner NSR S306C (trade name of Nikon Co., Ltd.) to expose the photomask surface at an exposure intensity of 0.01 mJ/cm²Pulse, repetition frequency 4000 Hz until 500J/cm²Until the irradiation amount is reduced.

The observation of the irradiated 6-inch photomask was performed by a laser foreign matter inspection apparatus, and the test pattern portion and the glass portion were free from the occurrence of fog and foreign matter. The coating volume ratio was set to 0.94.

[ example 3 ]

Next, the amount of the adhesive applied was changed in the same manner as in example 2 using the same frame as in example 2, and the amount of the adhesive applied (applied volume ratio 0.98) was set so that the adhesive layer thickness was 0.4 mm, the end face width was 1.55 mm, the side wall face angle was 75 °, and the side wall face angle of the adhesive layer formed was 76 °.

The error between the set value of 75 ° and the actual measured value of 76 ° is acceptable for experimental purposes. The operation was continued by mounting the mask on an ArF excimer laser scanner NSR S306C (trade name of Nikon Co., Ltd.) with an exposure intensity of 0.01 mJ/cm²Irradiation with/pulse frequency of 4000 Hz to 500J/cm²The irradiation amount of (3).

The observation on the irradiated 6-inch photomask was performed by a laser foreign matter inspection apparatus, and the test pattern portion and the glass portion were free from fogging and the occurrence of foreign matter.

[ example 4 ]

Further, in order to confirm that the side wall surface angle of the allowable limit in the present invention is 90 °, the coating amount of the adhesive was changed to set the coating amount (coating volume ratio 1.0) so that the adhesive layer thickness is 0.4 mm, the end surface width is 1 mm, and the side wall surface angle is 90 ° in the same frame as in example 3 and by the same process as in example 3.

Mounted on a photomask surface of an ArF excimer laser scanner NSR S306C (trade name of Nikon corporation) with an exposure intensity of 0.01 mJ/cm²Irradiation was carried out at a repetition frequency of 4000 Hz per pulse until an irradiation of 2 shots was carried out at 500J/cm.

When the irradiated 6-inch photomask was observed with a laser foreign matter inspection apparatus, the test pattern portion and the glass portion were free from the occurrence of haze and foreign matter.

The limit value of the side wall surface angle in the present invention is set to 90 °, and in the above embodiment, it is closer to 90 ° from a smaller angle (45 °).

In the comparative example, the approach was performed from a larger angle (135 °) with a target of 90 °.

First, as a pellicle frame, a frame outer dimension of 149 mm × 122 mm × 5.8 mm, a frame thickness of 2 mm, a C-plane dimension C of both end surfaces: 0.2 mm A7075-T651 aluminum alloy frame. And a vent hole with the diameter of 0.5 mm is arranged at one center of one side surface of the frame.

The frame and the surface were cleaned, and then glass beads were used to discharge the glass beads at a pressure of about 147 kPa (1.5 kg/cm)²) The surface of the sandblast apparatus (2) was roughened by performing surface treatment for 1 minute. The frame was then washed in a NaOH treatment bath for 10 seconds, and then anodized at a liquid temperature of 18 ℃ with a 14% sulfuric acid aqueous solution at a formation voltage of 10V (1.3A).

Subsequently, black dyeing and hole sealing treatment were performed to form a black oxide film on the surface. Thereafter, washing was performed for 5 minutes while using ultrapure water and an ultrasonic washing apparatus.

Next, a spray coating apparatus was used to coat the inner surface of the frame with a silicone adhesive: KR-3700 (trade name, manufactured by shin Etsu chemical Co., Ltd.) with a thickness of 10 μm.

Then, a filter with the material of PTFE, the dust filtration size of 0.1-3.0 μm, the filtration capacity of 99.9999%, the width of 8 mm, the height of 2.5 mm and the thickness of 300 μm is arranged at the vent. The filter has a filter portion for removing dust, and the outside has a chemical filter.

Then, teflon AF 1600 (trade name, manufactured by dupont, usa) was dissolved in a fluorine-based solvent fluorinert FC-75 (trade name, manufactured by 3M, usa) to obtain a solution with a concentration of 8%.

Then, a transparent film having a thickness of 0.83 μm was formed from the solution on a mirror-polished silicone substrate surface having a diameter of 250 mm and a thickness of 600 μm by a spin coater.

Then, a frame having an outer dimension of 200 mm × 200 mm × 5 mm in width and a thickness of 5 mm was bonded to the film with an epoxy adhesive agent Aralditerapid (trade name manufactured by Showa polymer Co., Ltd.), and peeled off from the substrate surface.

Next, one end face of the aluminum alloy frame prepared as described above was coated with an acrylic adhesive. The amount of coating was 1.06 times the set volume ratio, so that the end face width was 1.8 mm and the side wall face angle was 135 °.

The frame was heated at 100 ℃ for 3 minutes to cure it. The semi-cured adhesive layer was made to have a surface flatness of 10 μm, and the surface of the adhesive was flattened by pressing with a pressing device having a pressing plate having a release layer formed on the surface.

The side wall surface angle of the obtained adhesive layer was 135 °, and the end surface width was 1.8 mm.

On one end face of the aluminum alloy frame, a fluorine-based high-molecular polymer (CTX) (trade name, manufactured by Asahi glass (Ltd)) diluted in a fluorine-based solvent (CTSOLVE 180, manufactured by Asahi glass (Ltd)) was applied, heated at 100 ℃ for 10 minutes, dried and cured. Then, a PE T liner was prepared, and the liner was bonded to the photomask adhesive by using a liner bonding apparatus having a CCD camera image processing position determining mechanism.

Next, after the prepared teflon AF 1600 (described above) was adhered to the film surface, the frame was heated with an IR lamp to fuse the frame and the film.

The two frames are fixed by mounting the dustproof thin film assembly frame on a fixing clamp with the bonding surface facing upwards, so that the relative positions of the two frames do not shift. Then, the frame outside the pellicle frame was pulled up and fixed to give a tension of about 0.5N/m (0.5 g/cm) to the pellicle portion outside the pellicle frame.

Then, while dropping fluorine-based solvent fluoride FC 75 (trade name, manufactured by dupont) at a rate of 10 μ l per minute by using a tube type liquid dispenser, the knife was moved along the peripheral edge of the adhesive portion of the pellicle frame to cut off the unnecessary film portion outside the pellicle frame.

The completed pellicle was cleaned under the formation condition that the concentration of the acid component remaining on the surface was 1 ppb or less, and was attached to a 6-inch photomask substrate made of quartz glass having a Cr test pattern.

Next, the frame was placed on an ArF excimer laser scanner NSR S306C (trade name, Nikon corporation) and exposed to light at an intensity of 0.01 mJ/cm on the photomask surface²Pulse, irradiation was carried out at a repetition frequency of 4000 Hz to 500J/cm²The irradiation amount of (3).

When the irradiated 6-inch photomask was observed with the laser foreign matter inspection apparatus, the haze and the foreign matter were not observed in the center of the test pattern, but the haze was observed in the pattern portion near the frame. The frame was analyzed by a laser Raman spectrometer to obtain a hydrocarbon compound. The hydrocarbon compound is a product (presumably) obtained by decomposing an acrylic pressure-sensitive adhesive.

Comparative example 2

Next, as a pellicle frame, a pellicle frame having an outer frame dimension of 149 mm × 122 mm × 5.8 mm, a frame thickness of 2 mm, and a C-plane dimension of both end surfaces of C: 0.2 mm and A7075-T651. And a vent hole with the diameter of 0.5 mm is arranged at one center of one side surface of the frame.

After the surface of the frame was cleaned, glass beads were used and the discharge pressure was about 147 kPa (1.5 kg/cm)²) The surface of the sand blast apparatus (2) was roughened by performing surface treatment for 1 minute. The frame was then washed in a NaOH treatment bath for 10 seconds, and then anodized at a solution temperature of 18 ℃ in a 14% sulfuric acid aqueous solution at a formation voltage of 10V (1.3A).

Then, black dyeing and sealing treatment were performed to form a black oxide film on the surface. Thereafter, 5 minutes of combined washing with ultrapure water and an ultrasonic washing apparatus was conducted.

Next, a spray coating apparatus was used to coat the inner surface of the frame with a silicone adhesive: KR-3700 (trade name, manufactured by shin-Etsu chemical Co., Ltd.) was coated at 10 μm.

Then, a filter with the material of PTFE, the dust filtering size of 0.1-3.0 μm, the filtering capacity of 99.9999%, the width of 8 mm, the height of 2.5 mm and the thickness of 300 μm is arranged at the vent. The filter has a filter portion for removing dust, and the outer side has a chemical filter.

Then, teflon AF 1600 (trade name, manufactured by dupont, usa) was dissolved in a fluorine solvent fluorinert FC-75 (trade name, manufactured by 3M, usa) to obtain a solution with a concentration of 8%.

Next, the solution was formed into a transparent film having a thickness of 0.83 μm on a mirror-polished silicone substrate having a diameter of 250 mm and a thickness of 600 μm by means of a spin coater.

Then, a frame having an outer dimension of 200 mm × 200 mm × 5 mm in width and a thickness of 5 mm was attached to the film with an epoxy adhesive agent Aralditerapid (trade name manufactured by Showa polymer Co., Ltd.), and then peeled from the substrate surface.

Next, one end surface of the aluminum alloy frame prepared as described above was coated with an acrylic pressure-sensitive adhesive. The amount of coating was set to a volume ratio of 1.04, the width of the end face was 1.72 mm, and the side wall angle was 120 °.

The frame was heated at 100 ℃ for 3 minutes to effect precuring. The surface flatness of the semi-cured adhesive layer was set to 10 μm, and the adhesive surface was pressed flat by a pressing plate pressing apparatus having a release layer formed thereon.

The side wall angle of the obtained adhesive layer was 121 °, and the end face width was 1.72 mm.

The error between the set value of 120 ° and the measured value of 121 ° is tolerable for the purpose of the experiment and the operation is continued.

On the other end face of the aluminum alloy frame, a fluorine-based solvent CTSOLVE 180 (trade name of Asahi glass (manufactured by Co.)) diluted with a fluorine-based polymer CTX (trade name of Asahi glass (manufactured by Co.)) was applied, heated at 100 ℃. Then, a PET liner was prepared, and the prepared liner was attached to a photomask adhesive by using a liner attaching apparatus equipped with a CCD camera image processing position determining mechanism.

Next, after the film was adhered to the surface of the prepared teflon AF 1600 (described above), the frame was heated with an I R lamp to fuse the frame and the film.

The two frames are fixed by mounting the pellicle assembly frame on a fixing jig with the attachment surface facing upward so that the relative positions of the frames do not shift. Then, the frame outside the pellicle frame was pulled up and fixed to give a tension of 0.5N/m (0.5 g/cm) to the pellicle portion outside the pellicle frame.

Next, using a knife attached to the SCARA robot, while dropping fluorine-based solvent fluoride FC 75 (trade name, manufactured by dupont) at a rate of 10 μ l per minute by using a tube-type liquid dispenser, the knife was moved along the peripheral edge of the adhesive portion of the pellicle frame, and the unnecessary film portion outside the pellicle frame was cut off.

The completed pellicle was cleaned to a residual acid content concentration of 1 ppb or less, and was attached to a 6-inch photomask substrate made of quartz glass on which a Cr test pattern was formed.

The frame was then mounted on an ArF excimer laser scanner NSR S306C (trade name of Nikon Co., Ltd.) to expose the photomask surface at an exposure intensity of 0.01 mJ/cm²Pulse, repetition frequency 4000 Hz, irradiation was carried out until the dose was 500J/cm²。

The observation on the irradiated 6-inch photomask was performed by a laser foreign matter inspection apparatus, and the generation of foreign matter was not confirmed in the center of the test pattern, but was confirmed in the pattern portion near the frame. The frame was analyzed by a laser Raman spectrometer to obtain a hydrocarbon compound. The hydrocarbon compound is a product produced by decomposing an acrylic pressure-sensitive adhesive.

Through the above experiments, the occurrence of mist was confirmed when the side wall surface angles of the adhesive agent layer were 135 ° and 121 °.

Further, comparative example 1 was performed in order to confirm the state of approaching the limit value of the side wall surface angle of 90 °.

Comparative example 1

As a pellicle frame, an aluminum alloy frame A7075-T651 was prepared, which had an outer frame size of 149 mm X122 mm X5.8 mm, a frame thickness of 2 mm, and a C-plane size (C: 0.2 mm) at both end faces. And a vent hole with the diameter of 0.5 mm is arranged at one center of one side surface of the frame.

After the surface of the frame was cleaned, glass beads were used and the discharge pressure was about 147 kPa (1.5 kg/cm)²) The surface of the sandblast apparatus (2) was roughened by performing surface treatment for 1 minute. The frame was then washed in a NaOH treatment bath for 10 seconds, and then anodized at a formation voltage of 10V (1.3A) and a 14% sulfuric acid aqueous solution at a liquid temperature of 18 ℃.

Then, black dyeing and sealing treatment were performed to form a black oxide film on the surface. Thereafter, the apparatus was cleaned with ultrapure water and ultrasonic waves for 5 minutes.

Next, a spray coating apparatus was used to coat the inner surface of the frame with a silicone adhesive: KR-3700 (trade name, manufactured by shin Etsu chemical Co., Ltd.) was coated to a thickness of 10 μm.

Then, the vent is provided with a filter which is made of PTFE, has the dust filtering size of 0.1-3.0 μm, the filtering capacity of 99.9999 percent, and has the width of 8 mm, the height of 2.5 mm and the thickness of 300 μm. The filter has a filter portion for removing dust and a chemical filter on the outside.

Then, teflon AF 1600 (trade name, manufactured by dupont, usa) was dissolved in a fluorine solvent fluorinert FC-75 (trade name, manufactured by 3M, usa) to obtain a solution with a concentration of 8%.

Then, a transparent film having a thickness of 0.83 μm was formed from the solution on a silicone substrate surface polished with a mirror having a diameter of 250 mm and a thickness of 600 μm by a spin coater.

Then, a frame having an outer dimension of 200 mm × 200 mm × 5 mm in width and a thickness of 5 mm was bonded to the film with an epoxy adhesive agent Aralditerapid (trade name manufactured by Showa polymer Co., Ltd.), and peeled off from the substrate surface.

Next, one end face of the aluminum alloy frame prepared as described above was coated with an acrylic adhesive.

At this time, an adhesive was applied in a volume ratio of 1.02 times, so that the end face width was 1.7 mm and the side wall angle was 110 °.

The frame was heated at 100 ℃ for 3 minutes to effect precuring. The semi-cured adhesive layer was formed on a surface having a surface flatness of 10 μm, and the surface of the adhesive was flattened by pressing with a pressing device having a pressing plate having a release layer formed on the surface.

The side wall angle of the obtained adhesive layer was 107 ℃ and the end face width was 1.66 mm.

On the other end face of the aluminum alloy frame, a fluorine-based solvent CTSOLVE 180 (trade name, manufactured by asahi glass (ltd.)) diluted fluorine-based high polymer CTX (trade name, manufactured by asahi glass (ltd.)) was applied, heated at 100 ℃ for 10 minutes, and dried and cured. Then, a PE T liner was prepared and attached to the photomask adhesive by a liner attaching apparatus having a CCD camera image processing position determining machine.

Next, after the film was adhered to the surface of the prepared teflon AF 1600 (described above), the frame was heated with an I R lamp to fuse the frame and the film.

The two frames are mounted on a fixing jig with the attachment surface of the pellicle frame facing upward, and fixed so that the opposing positions do not shift. Then, the frame outside the pellicle frame was pulled up and fixed, and a tension of about 0.5N/m (0.5 g/cm) was applied to the film portion outside the pellicle frame. Then, while dropping fluorine-based solvent fluoride FC 75 (trade name, manufactured by dupont) at a rate of 10 μ l per minute, a knife attached to the SCARA robot was moved along the periphery of the adhesive portion of the pellicle frame, and the unnecessary film portion outside the pellicle frame was cut and removed.

The completed pellicle was cleaned to a residual acid content concentration of 1 ppb or less, and was attached to a 6-inch photomask substrate made of quartz glass on which a Cr test pattern was formed.

Next, the frame was mounted on an ArF excimer laser scanner NSR S306C (trade name, Nikon Co., Ltd.) and exposed to light at an intensity of 0.01 mJ/cm on the photomask surface²Pulse, repetition frequency 4000 Hz, light irradiation was carried out until the irradiation dose was 500J/cm²The irradiation amount of (3).

When the irradiated 6-inch photomask was observed with the laser foreign matter inspection apparatus, the haze and the foreign matter were not observed in the center of the test pattern, but the haze was observed in the pattern portion near the frame. The frame was analyzed by a laser Raman spectrometer to obtain a hydrocarbon compound. The hydrocarbon compound is a product (presumably) produced by decomposition of the acrylic pressure-sensitive adhesive.

[ TABLE 1 ]

[ description of symbols ]

1: dustproof pellicle assembly frame

2: adhesive layer for attaching dustproof film

3: dustproof film

4: adhesive layer for photomask adhesion

5: underlayer for protecting photomask adhesive

Claims (1)

1. A method of manufacturing a pellicle for lithography, the method comprising:

attaching a pellicle to the pellicle assembly frame,

forming an adhesive layer on an upper end annular surface of the pellicle assembly frame,

forming a photomask adhesive layer on a lower end annular surface of the dustproof pellicle assembly frame, wherein a cross section of the photomask adhesive layer is substantially rectangular or substantially trapezoidal, wherein an upper end face of the cross section is parallel to the lower end annular surface of the dustproof pellicle assembly frame, and wherein an angle α of a side of the cross section to the lower end annular surface of the dustproof pellicle assembly frame is not less than 45 ° and is 90 ° or less, and

semi-curing, and then forming the photomask adhesive layer into a flat layer by pressing, wherein the photomask adhesive layer is made of a thermosetting type photomask adhesive,

attaching a releasable liner to the photomask adhesive layer, an

And curing the photomask adhesive layer, and simultaneously attaching the dustproof thin film to the dustproof thin film assembly frame.