JP2022010209A - Pellicle - Google Patents

Abstract

Kind Code: A1 A pellicle having an area of 1000 cm 2 or more is used when an exposure device with a resolution of 2.0 μm or higher is used for FPD, and the pellicle has little effect on pattern dimension accuracy and does not cause defects in transferred patterns. intended to provide A pellicle frame having a rectangular opening with an area of 1000 cm2 or more in plan view, a pellicle film stretched and supported on one end surface of the pellicle frame so as to cover the opening, and the pellicle. and a mask adhesive on the other end face of the frame, wherein the pellicle film has a film thickness of 1.0 μm or more and 3.0 μm or less, and a film thickness variation within the pellicle film surface is 80 nm or less. is the pellicle. [Selection figure] None

Description

The present invention relates to a pellicle.

Conventionally, in the manufacture of semiconductor circuit patterns and the like, dustproof means generally called a pellicle is used to prevent foreign matter from adhering to a photomask or a reticle. The pellicle is, for example, a transparent polymer film such as nitrocellulose or a cellulose derivative or a fluoropolymer having a thickness of 10 μm or less on the upper edge surface of a frame having a thickness of about several millimeters having a shape matching the shape of a photomask or a reticle. (Hereinafter referred to as "pellicle film") is stretched and adhered, and an adhesive is applied to the lower edge surface of the frame, and a protective film is adhered on the adhesive with a predetermined adhesive force. Is.

The pressure-sensitive adhesive is for adhering a pellicle to a photomask or a reticle, and a protective film is used to maintain the adhesive strength of the pressure-sensitive adhesive until the pressure-sensitive adhesive is used for the purpose. It protects the adhesive surface.

Such pellicle is generally supplied from the manufacturer of the pellicle to the manufacturer of the photomask or the reticle, where the pellicle is attached to the photomask or the reticle, and then the semiconductor manufacturer, the panel manufacturer, etc. It is supplied to the manufacturer who performs lithography.

As the pellicle film, the optimum material is selected and used according to the light source used for exposure. For example, in the case of a short wavelength of KrF laser (248 nm) or less, a fluorine-based resin having sufficient transmittance and light resistance is used.

On the other hand, for FPD, a high-pressure mercury lamp or an ultra-high pressure mercury lamp is generally used as a light source, and since a broadband wavelength of 240 nm to 600 nm is used, a cellulosic resin such as nitrocellulose, ethyl cellulose, or propionate cellulose, or cyclo Olefin resins, fluororesins, polyvinyl acetal resins and the like are used.

Further, even for semiconductors, there is exposure using a long wavelength such as g & i line, and even in that case, a cellulose-based resin, a cycloolefin-based resin, a polyvinyl acetal resin, or the like has already been used in addition to the fluorine-based resin. (For example, refer to Patent Documents 1 to 3)

Even in FPDs, there is a demand for circuits with finer line widths for the purpose of improving productivity.
High exposure wavelengths are required, and large-sized pellicle films have been developed to meet the demands. (See, for example, Patent Document 4)

Japanese Unexamined Patent Publication No. 04-081854 Japanese Unexamined Patent Publication No. 01-133052 Japanese Unexamined Patent Publication No. 07-199451 Japanese Unexamined Patent Publication No. 2012-212043

Since many patterns of conventional FPD exposure wavelengths do not require much resolution, a pellicle film can be used without problems if the average transmittance is 90% or more in broadband. However, in recent years, even in the world of FPDs, exposure equipment focusing on high-resolution and high-precision alignment has been developed for cutting-edge high-performance mobile devices such as smartphones, high-definition organic EL panels, and liquid crystal panels. There is.

Therefore, in the same magnification projection exposure, a circuit with higher resolution is provided by using a single wavelength of i-line or a mixed wavelength of a specific wavelength such as i-line, g-line, j-line (hereinafter referred to as "specific mixed wavelength"). There is a movement to draw. At that time, in order to reduce the geometrical shape error between the mask pattern and the design pattern, which is called pattern dimensional accuracy (CD), the exposure machine maker and the mask maker have devised various measures for the exposure machine and the mask.

G & i-ray wavelengths have already been used for semiconductors, and by designing the film thickness as a pellicle that can share both g-line and i-line as in Patent Documents 1 to 3, the transmittance is increased and there is no problem with the pellicle. providing.

However, for FPDs (flat panel displays) with an area of 1000 cm ² or more, when exposed with an i-line single wavelength or a specific mixed wavelength aiming for a resolution of 2.0 μm or higher (referred to as “resolution 2.0 μm or less”), the transmittance Even if you make a pellicle only by paying attention to it, the resolution will be reduced, the line width of the transferred pattern will be narrowed, the pattern will come into contact with each other, and the pattern will be cut off. There was found.

Conventionally, the pellicle can be used without any problem as long as it has a transmittance as long as it protects the mask from foreign substances. However, it became for high-definition, and even if the CD was made smaller by the panel maker and the exposure machine maker, when the pellicle was pasted and exposed at the end, the CD became larger than expected, and it was discovered for the first time that the pellicle had an adverse effect on the pattern. rice field.

The present invention has been made in view of the above problems, and is a large pellicle having an area of 1000 cm ² or more used when using an exposure machine for FPD with a resolution of 2.0 μm or less.
It is an object of the present invention to provide a pellicle that has little influence on the pattern dimensional accuracy and does not cause a defect in the transferred pattern.

As a result of diligent studies to solve the above problems, the present inventors have found that the above problems can be solved by keeping the film thickness variation in the pellicle film surface within a certain range, and have completed the present invention. rice field.

That is, the present invention is as follows.
[1]
A pellicle frame having an opening having a rectangular shape in a plan view having an area of 1000 cm ² or more, a pellicle film stretched and supported on one end surface of the pellicle frame so as to cover the opening, and the pellicle frame. A pellicle containing a mask adhesive on the other end face of the
A pellicle in which the film thickness of the pellicle film is 1.0 μm or more and 3.0 μm or less, and the film thickness variation in the pellicle film surface is 80 nm or less.
[2]
The pellicle according to [1], wherein the transmittance of the pellicle film with respect to a wavelength of 365 nm is 95% or more.
[3]
When exposed using the mask to which the pellicle is attached, the in-plane range of pattern dimensional accuracy in the transferred L / S (vertical stripe pattern) is 200 nm or less, [1] or [2].
] The pellicle described in.
[4]
The pellicle according to any one of [1] to [3], wherein the in-plane range of pattern dimensional accuracy in the contact hole to be transferred is 300 nm or less when exposed using the mask to which the pellicle is attached.

According to the present invention, it is a pellicle having an area of 1000 cm ² or more that can be used when using an exposure machine for FPD with a resolution of 2.0 μm or more, and has little influence on the pattern dimensional accuracy, and the transferred pattern is defective. It is possible to provide a pellicle that does not cause the above.

It is an SEM photograph of the pattern on the wafer of Example 1. FIG. 6 is an SEM photograph of a pattern on a wafer of Comparative Example 1. It is a figure which shows the line and space (L / S) pattern in the CD measurement. 6 is an SEM photograph of a contact hole transferred when exposed using the pellicle prepared in Example 4. 6 is an SEM photograph of a contact hole transferred when exposed using the pellicle produced in Comparative Example 1.

Hereinafter, embodiments of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail, but the present invention is not limited thereto, and various modifications can be made without departing from the gist thereof. Is.

[Pellicle]
The pellicle of the present embodiment has a pellicle frame having an opening having a rectangular shape in a plan view having an area of 1000 cm ² or more, and a pellicle film stretched and supported on one end surface of the pellicle frame so as to cover the opening. And a pellicle containing a mask pressure-sensitive adhesive on the other end surface of the pellicle frame, the thickness of the pellicle film is 1.0 μm or more and 3.0 μm or less, and the film thickness in the pellicle film surface. The variation is 80 nm or less.

(Pellicle membrane)
The pellicle film in the present embodiment is stretched and supported on one end surface of the pellicle frame so as to cover the opening. The components constituting such a pellicle membrane are not particularly limited, but for example, cellulose derivatives (nitrocellulose, cellulose acetate, etc.)
Cellulose acetate propionate, cellulose acetate butyrate, etc., or a mixture of two or more of these), a fluoropolymer (tetrafluoroethylene-vinylidene fluoride-hexafluoropropylene ternary copolymer, polymer with a cyclic structure in the main chain) Teflon AF (trade name) manufactured by Du Pont, Cytop (trade name) manufactured by Asahi Glass Co., Ltd.,
Polymers such as argoflon (trade name) manufactured by Audimont Co., Ltd. are used.

For the ultra-high pressure mercury lamp, which is the light source of the 1x projection exposure liquid crystal exposure machine currently used, cellulose acetate propionate, cellulose acetate butyrate, Cytop, Teflon AF, etc. are used in terms of light resistance and cost. Fluorine-based polymers are preferably used.

The above polymers can be dissolved in suitable solvents (ketone-based solvent, ester-based solvent, alcohol-based solvent, fluorine-based solvent, etc.) and used as a polymer solution. In particular, an ester solvent such as ethyl lactate is preferable for the above-mentioned cellulose acetate propionate and cellulose acetate butyrate. Further, for a fluorine-based polymer such as Cytop or Teflon AF, a fluorine-based solvent such as tris (perfluorobutyl) amine is preferable. The polymer solution is filtered by a depth filter, a membrane filter or the like, if necessary.

The thickness of the pellicle film is 1.0 to 3.0 μm, preferably 1.4 to 2.8 μm, more preferably 1.5 to 2.6 μm, still more preferably 1.6 to 2 It is 5.5 μm. When the thickness of the pellicle film is within the above range, the optical path of light is shortened and the phase difference depending on the wavelength is small, so that it is suitable when i-line single wavelength or specific mixed wavelength is used. Further, when the thickness of the pellicle film is within the above range, the transmittance tends to be adjusted to 95% or more more easily. Further, when the thickness of the pellicle film is within the above range, the film can be peeled off cleanly without causing tearing when the film is peeled off from the substrate at the time of film formation, so that the yield is further improved. Further, it is preferable because the film does not break when the pellicle is handled, and further, it does not break when the foreign matter adhering to the pellicle film is removed by air blow.

The thickness of the pellicle film can be reduced by adjusting the concentration of the polymer solution and the coating conditions (for example, coating speed, drying time, etc.). Further, the thickness of the pellicle film can be measured by the method described in Examples.

The film thickness variation in the film surface of the pellicle film is 80 nm or less, preferably 70 nm or less, more preferably 50 nm or less, still more preferably 45 nm or less, still more preferably 35 nm or less. Ideally, the film thickness variation in the film surface of the pellicle film is 0 nm, but in the case of the pellicle, since the area of the outer shape of the pellicle frame is 1000 cm ² or more, it is more difficult to make the variation 0 nm in production. From such a production problem, it is generally considered that 10 nm or more contains production variation, but this point is not particularly limited. Further, since the film thickness variation in the film surface of the pellicle film is within the above range, even if the area of the pellicle is large, the CD is contained in a predetermined range and the CD variation in the surface is small, which is preferable. When the refractive index is n and the film thickness is d, the optical path of light (distance felt by light) can be easily expressed by n × d. In fact, since light is related not only to the right angle to the film surface but also to the phase angle, the incident from an oblique angle is also included. Therefore, we believe that reducing the film thickness variation will enable us to draw similar patterns throughout the pellicle. In particular, in the case of projection 1x exposure, it is considered that this influence is stronger.

The variation in the film thickness in the film surface of the pellicle film can be easily adjusted by adjusting the spin coater or the slit coat, and can be reduced by adjusting the rotation speed, the concentration of the polymer solution, and the nozzle coating conditions. Further, the film thickness variation in the film surface of the pellicle film can be measured by the method described in Examples.

When exposed using a mask to which a pellicle is attached, the in-plane range of the transferred CD is preferably 200 nm or less as an L / S (vertical stripe pattern), more preferably 150.
It is nm or less, more preferably 100 nm or less, still more preferably 80 nm or less.
Further, when a contact hole is formed when exposed using a mask to which a pellicle is attached, the in-plane range of the CD in the contact hole to be transferred is preferably 300 n.
It is m or less, more preferably 250 nm or less, still more preferably 200 nm or less, still more preferably 150 nm or less.
The in-plane range of the CD in the L / S and contact holes is within the above range.
Even if the area is large in the case of 1x projection exposure with a resolution of 2.0 μm or more, the space between the lines touches, the desired hole cannot be secured, and the pattern is poorly cut. I tend not to.

The transmittance of the pellicle film with respect to the wavelength of the i-line (365 nm) is preferably 95% or more, more preferably 97% or more, still more preferably 98% or more. The upper limit of the transmittance of the pellicle film with respect to the wavelength of the i-line (365 nm) is not particularly limited, but is preferably 100%, more preferably 99.8% or less. The resolution of the pellicle film tends to be further improved when the transmittance of the i-line (365 nm) with respect to the wavelength is 95% or more. This has a resolution of 2.0 μm, especially after 1.5 μm, and even 1.2 μm.
This is because the i-line is used to achieve the following. In addition, i-line (365n) of the pellicle membrane
Since the transmittance for the wavelength of m) is 99.8% or less, the film thickness variation is suppressed, and even a large-area film tends to be produced with good productivity. In particular, when the transmittance is 95% or more and the film thickness variation is 80 nm or less, the CD tends to be more stable.

(Frame for pellicle)
The frame for the pellicle in the present embodiment includes an opening having a rectangular shape in a plan view having an area of 1000 cm ² or more. The shape of the frame for the pellicle is a rectangle or a square similar to the mask shape. Therefore, the frame for the pellicle is also a rectangle or a square similar to the mask shape.

The cross-sectional shape of each side of the pellicle frame is not particularly limited, such as rectangular, H-shaped, and T-shaped, but a rectangular shape is most preferable. The cross section may have a hollow structure.

The thickness of the pellicle frame is preferably 3.0 mm or more, more preferably 3.5 mm or more, and particularly preferably 4.0 mm or more. On the other hand, the upper limit of the thickness of the pellicle frame is preferably 10 mm or less, more preferably 8 mm or less, still more preferably 7 mm or less.

The width of the frame for the pellicle is preferably between 3.5 mm and 30 mm. Within this range, it is preferable because it can withstand the tension of the pellicle film while ensuring an effective exposure area. The lower limit of the width of the pellicle frame is more preferably 4 mm or more, further preferably 6 mm or more, and it is preferable to change the width so as to withstand the membrane tension according to the area of the pellicle frame. On the other hand, the upper limit of the width of the frame for the pellicle is preferably 30 mm or less, more preferably 25 mm.
Below, it is more preferably 19 mm or less. The width may be the same as the width of either the long side or the short side, or may be an independent width.

The frame for the pellicle is, for example, aluminum, aluminum alloy (5000 series, 6000 series, 7000 series, etc.), iron and iron alloy, ceramics (SiC, AlN, Al ₂ O ₃ , etc.), composite material of ceramics and metal (Chemicals and metal). Al-SiC, Al-AlN, Al-Al ₂ O ₃ etc.), carbon steel, tool steel, stainless steel series, magnesium alloy, and polycarbonate resin,
It is made of a resin such as acrylic resin and has a substantially rectangular shape in a plan view. Pellicle
Since it adheres to the mask via the mask pressure-sensitive adhesive layer, a material having high rigidity and a relatively small weight is preferable, and a material such as aluminum, an aluminum alloy, a magnesium alloy, or a resin is preferable.

The area of the rectangular opening in the plan view provided in the frame for the pellicle in the present embodiment is 1000.
cm ² or more, preferably 5000 cm ² or more, more preferably 6000 cm ²
That is all. The effect of the present invention is further exhibited when the area of the rectangular opening in the plan view provided by the frame for the pellicle is 1000 cm ² or more. Considering the mask used for manufacturing the FPD, the upper limit of the area of the rectangular opening in a plan view is sufficient if it is 35,000 cm ² .

The length of the long side of the pellicle frame may be 400 mm or more, preferably 800 mm or more, and 2100 mm or less.

(Inner wall, ventilation holes, filters)
If necessary, apply an adhesive (acrylic, vinyl acetate, silicone, rubber, etc.) or grease (silicone, fluorine, etc.) to capture foreign matter on the inner wall surface or the entire surface of the pellicle frame. You may.

In addition, if necessary, a minute hole is made to penetrate the inside and outside of the pellicle frame so that the pressure difference between the inside and outside of the space formed by the pellicle and the photomask is eliminated, so that the bulge and dent of the film can be prevented. It can be prevented.

Further, at this time, it is preferable to attach a foreign matter removing filter to the outside of the fine hole because the atmospheric pressure can be adjusted and foreign matter can be prevented from entering the space formed by the pellicle and the photomask.

When the space volume formed by the pellicle and the photomask is large, it is preferable to provide a plurality of these holes or filters because the recovery time of the swelling or dent of the film due to the atmospheric pressure fluctuation is shortened.

Since the pellicle frame in the present embodiment can have appropriate rigidity and flexibility by satisfying the above requirements, there is no distortion of the frame due to the expansion of the pellicle film.
It is possible to follow not only the bending when the pellicle is handled alone, but also the bending of the mask itself in the subsequent handling after being attached to the mask. as a result,
Since the pellicle does not wrinkle and can follow the bending of the mask, it has an excellent effect that no air path is generated.

(Manufacturing method of pellicle membrane)
As the pellicle film, for example, a thin film formed from a polymer solution is used. Tension is present in this thin film. On the other hand, this tension is necessary to prevent the pellicle film from bending or wrinkling.

When the pellicle film is bent or wrinkled, the pellicle film vibrates greatly and is difficult to remove when the foreign matter adhering to the pellicle film is removed by air blow. In addition, the foreign matter inspection machine for the pellicle membrane does not function normally because the height of the pellicle membrane changes depending on the location. In addition, problems such as causing an error in the optical height measurement of the pellicle film occur.

The polymer solution film forming method includes a spin coating method, a roll coating method, a knife coating method, a casting method and the like, but the spin coating method is preferable from the viewpoint of uniformity and control of foreign matter. After forming a film on the film-forming substrate by the spin coating method, a uniform film is formed by drying the solvent with a hot plate, a clean oven, (far) infrared heating, or the like, if necessary. As the film-forming substrate at this time, synthetic quartz, molten quartz, non-alkali glass, low-alkali glass, soda lime glass and the like can be used.

Since the size of the substrate for film formation of the pellicle according to the present embodiment is large, the film-forming substrate may be cracked due to temperature spots during drying. In order to prevent this, it is preferable that the coefficient of thermal expansion of the film-forming substrate is small. In particular, it is preferable that the coefficient of linear expansion from 0 ° C to 300 ° C is 50 × 10 ^-7 m / ° C or less.

Further, the surface of the substrate for film formation may be subjected to a mold release treatment in advance with a material such as silicone or fluorine. Further, the above-mentioned pellicle film may be a single layer, but by forming a layer having a lower refractive index than the pellicle film (that is, an antireflection layer) on one side or both sides of the pellicle film, the transmittance with respect to the exposed light beam is formed. Can be enhanced, which is preferable.

As the material of the antireflection layer, a fluoropolymer (tetrafluoroethylene-vinylidene fluoride-hexafluoropropylene ternary copolymer, Teflon AF (trade name) manufactured by Du Pont, which is a polymer having a cyclic structure in the main chain). , Asahi Glass's Cytop (trade name), Audimont's Argoflon (trade name), polyfluoroacrylate, etc.) and materials with low refractive index such as calcium fluoride, magnesium fluoride, and barium fluoride are used. Will be done.

In the case of a polymer, the antireflection layer is formed by the same spin coating method as described above, and in the case of an inorganic substance, the antireflection layer is formed.
It can be formed by a thin film forming method such as vacuum deposition or sputtering. From the viewpoint of foreign matter, the spin coating method using a polymer solution is preferable. Teflon AF (trade name) manufactured by DuPont and Argoflon (trade name) manufactured by Audimond are preferable because they have a low refractive index and therefore have a high antireflection effect.

The pellicle film formed on the film-forming substrate as described above can be peeled off from the film-forming substrate by a temporary frame in which an adhesive is attached to an aluminum alloy, stainless steel, resin, etc., and replaced with a desired pellicle frame. good. Further, the desired pellicle frame may be adhered on the film-forming substrate and then peeled off from the film-forming substrate.

The pellicle film thus obtained is attached to the pellicle frame by applying tension to the pellicle frame.

(Membrane adhesive)
The film adhesive for adhering to the pellicle film and the pellicle frame is appropriately selected depending on the material of the pellicle film and the material of the pellicle frame. For example, epoxy-based, acrylic-based, silicone-based, and fluorine-based adhesives are used.

Further, as the curing method of the adhesive, a curing method suitable for each adhesive (heat curing, photo-curing, anaerobic curing, etc.) is adopted. Acrylic-based UV-curable adhesives are preferable from the viewpoints of dust generation, cost, and workability.

The mask adhesive for attaching the pellicle frame to the photo mask includes a hot melt adhesive (rubber type, acrylic type) that has adhesiveness to itself, and a tape type (base) in which the adhesive is applied to both sides of the base material. Acrylic-based, PVC-based sheets or rubber-based, polyolefin-based, urethane-based foams, etc. can be applied as materials, and rubber-based, acrylic-based, silicone-based, etc. adhesives are applied as adhesives). Will be done.

(Mask adhesive, liner)
In the pellicle according to the present embodiment, a relatively soft hot melt material or foam is suitable as the mask adhesive so that the pellicle can be uniformly attached to the photomask and the pellicle can be easily peeled off from the mask. In the case of a foam, dust generation from the foam can be prevented by covering the cross section with an acrylic or vinyl acetate-based adhesive material or a non-adhesive material.

The thickness of the mask adhesive is usually 0.2 mm or more, but is preferably 1 mm or more for uniform application to the photomask. In order to protect the adhesive surface of the mask adhesive until it is attached to the photomask, a polyester film that has been mold-released with silicone or fluorine is used.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

[Evaluation methods]
(1) Film thickness variation (nm)
Double-sided tape was attached to an aluminum frame having an outer dimension of 40 mm × 35 mm and a long side width and a short side width of 5 mm. This frame was attached to each of the nine measurement target locations (described later) of the pellicle membrane, and the pellicle membrane of the pellicle was cut out. After that, the cut out frame with a film was set in an ultraviolet visible spectrophotometer (Shimadzu Corporation, UV-1800) and measured (measurement wavelength 365).
nm). Of the nine measured film thicknesses at the measurement target locations, the value obtained by subtracting the thinnest film thickness from the thickest film thickness was defined as the film thickness variation.

(2) Film thickness (μm)
A frame with a film was cut out for each measurement target location at 9 points by the same method as the above-mentioned film thickness variation. The cut out frame with a film was measured, and the middle (average) between the thickest film thickness and the thinnest film thickness was taken as the film thickness.

(3) Transmittance (%)
A frame with a film was cut out for each measurement target location at 9 points by the same method as the above-mentioned film thickness variation. The cut out frame with a film was set in an ultraviolet visible spectrophotometer (Shimadzu Corporation, UV-1800), and the transmittance at 365 nm was measured. The arithmetic mean value of the transmittance at 9 points was taken as the transmittance.

(4) Method for measuring the in-plane range of a CD A silicon substrate (12 inches, 300 mmφ) was used as a film-forming substrate, and silane coupling was performed on the surface thereof to improve releasability. Next, the same polymer solution and conditions as in each example were used, and the film was formed so that the film thickness variation was the same. Then, the dried film was peeled off from the film-forming substrate on the temporary frame.

Then, the same mask adhesive as in the examples was applied to one end face of a black alumite aluminum alloy pellicle frame, and the film was protected with a polyester file as a protective film. The thickness of the protective film was 100 μm. The same film adhesive as in the examples was applied to the other end face of the pellicle frame, and the pellicle film on the temporary frame was adhered. The outer diameter of the pellicle frame is 122 mm x 149.
It was mm, the inner diameter was 118 mm × 145 mm, and the height was 4.8 mm.

A photoresist (photosensitive substance) on synthetic quartz glass (6025) having a chromium thin film layer.
After pre-baking, a pattern of 5 rows was drawn on the photoresist in a region of 100 mm × 100 mm using an electron beam exposure apparatus. The drawing shape is the same as that in FIG. 3 in one column, and the shape of the pattern is changed by changing the line width. One pattern is, for example, L / S as shown in FIG.
The line width (L) was set to 2.0 μm, and the space width (S) was set to 0.4 μm. The line width (L) was changed to 1.8 μm, 1.7 μm, and 1.6 μm with the same drawing shape. In addition, FIG.
Nine 2.0 μm contact holes were made near each L / S pattern as shown in the above, and the same was made near each drawing shape. Five rows of the same pattern as the one row thus prepared were produced. After the development treatment, the chromium layer portion exposed from the resist pattern was etched, and the resist pattern was transferred to the chromium layer. Finally, the resist residue was washed to prepare a reticle.

After that, the prepared pellicle was used as a reticle with a weight of 30 k using a simple mounter.
The gf and the weighting time were 60 sec.

The photoresist was uniformly applied on a silicon substrate (φ4 inch) with a spin coater, and then prebaked to solidify the photoresist. Next, using a reduction projection type exposure device (stepper), which is one of the semiconductor element manufacturing devices, the fine pattern of the reticle produced earlier is reduced to 1/5 by a reduction projection lens, and the wafer is coated with resist. Was projected and exposed while moving. The mixture was heated at 110 ° C. for 90 seconds and then immersed in an organic alkaline developer to remove the resist in the exposed portion. It was rinsed with ultrapure water several times to completely remove the exposed residue.

As the exposure conditions, the exposure intensity is 500 mW / cm ² and the exposure time is 285 msec to 445.
The condition of msec and focus of -0.3 to 0.7 μm was shaken. After the exposure, it was developed, and the condition for finding the condition that the CD was small for the pattern with the resolution of 2.0 μm of L / S was set by SEM.

Under the conditions determined above, the exposure intensity was 500 mW / cm ² , the focus was constant, the exposure time was set to 300 msec to 320 msec, the exposure was performed again, and the development was performed. The conditions for focus and exposure time were appropriately determined for the desired resolution.

(5) In-plane range measurement of CD The pattern on the wafer produced in (4) above is subjected to SEM (SU8000 scanning electron microscope manufactured by Hitachi High-Technologies Corporation) with an applied voltage of 1.0 kV, 30,000 to 35.
The observation was performed at 000 times, and the length of the center line of the 9 lines was measured at any three points with respect to the pattern of L / S resolution of 2.0 μm on the SEM, and the average was calculated. 18 places vertically (0)
.. (4 mm pitch) was performed, the shortest length was calculated from the longest length from each average value, and the value obtained by multiplying the value by 5 was defined as the in-plane range of the CD.
In addition, the diameters of 9 holes are calculated for a pattern with a resolution of 2.0 μm for contact holes, and the value obtained by multiplying the value of "2.0 μm-calculation result" by 5 is the surface of the CD in the contact hole. It was set to the inner range.

[Example 1]
Cellulose Acetate Propionate (CAP), a polymer that constitutes a pellicle membrane
4 80-20, manufactured by Eastman Chemical Company) and ethyl lactate as a solvent were mixed to prepare a solution having a solid content concentration of 4% by mass. 0 with nitrogen in this solution
.. The pressure was increased to 01 MPa, and filtration was performed through a membrane filter having a diameter of 0.1 μm.

A film-forming substrate was physically polished, physically polished, then chemically polished, and washed with pure water. The film-forming substrate was heated and dried at 100 ° C. for 2 hours in a clean oven, and then cooled to room temperature. Next, the diameter of the substrate for film formation and the diameter of 5 cm into which hexamethyldisilazane 20 cc was introduced.
A polyethylene container with an open top was sealed in a clean metal box at room temperature for 30 minutes. After taking out the film-forming substrate, it was heated in a clean oven at 100 ° C. for 2 hours. The film-forming substrate prepared in this way is set in a closed cup type spin coater, about 300 g of the previously prepared polymer solution is supplied onto the glass substrate, and the film-forming substrate is 90 at 330 rpm.
It was rotated for sec. The film-forming substrate was placed on a hot plate at 60 ° C. for 15 minutes, and the solvent in the polymer solution was evaporated to form a pellicle film on the film-forming substrate.

Aluminum alloy (606) with an outer shape of 1396 mm on one side, a width of 20 mm, and a thickness of 6 mm.
A temporary frame in which 1) was treated with black alumite and a hole was prepared. An epoxy adhesive was applied to this temporary frame, and the film was pressed and fixed to the pellicle film on the film-forming substrate. After the epoxy adhesive was cured, the temporary frame was gently raised, and the pellicle film was peeled off from the film-forming substrate on the temporary frame.

Next, as a frame for the pellicle, an aluminum alloy (505) having a Young's modulus of 70 [GPa]
A frame made of 2) having an outer dimension of 1150 mm × 785 mm, an outer corner R10 mm, an inner corner R2 mm, a long side width of 11 mm, a short side width of 10 mm, and a height of 5.2 mm was used. In addition, a total of eight through holes (vents) with a diameter of 1.5 mm were opened in the center of each long side of this frame, and the ends of each long side had a diameter of 2 mm for gripping and electrodes during alumite treatment. Depth 2 mm
A total of 4 holes are made in 2 holes each, and a handling groove with a width of 1.5 mm and a depth of 2.3 mm is cut in the center of both short sides in the height direction over the entire length of the short sides. bottom. After shot blasting the surface of the frame for pellicle, black alumite and sealing treatment were prepared.

An acrylic adhesive was applied to the inner wall surface of the pellicle frame to a thickness of about 10 μm.
A membrane filter made of ethylene tetrafluoride was attached to the vent with an acrylic adhesive. A hot melt resin made of SEBS (styrene-ethylene-butylene-styrene block co-association) was applied to one edge of the pellicle frame as a mask adhesive so as to have a width of 6 mm and a height of 1.6 mm. It was applied and molded. As a protective liner for protecting the surface of the hot melt resin, a polyester film having a thickness of 0.1 mm and subjected to a silicone mold release treatment was attached.

A urethane acrylate-based ultraviolet curable adhesive was applied to the opposite edge surface to which the adhesive was applied to the tip of the pellicle frame. Then, the pellicle film stretched on the temporary frame was placed, irradiated with ultraviolet rays to cure the ultraviolet curable adhesive, and the pellicle frame and the pellicle film were adhered to each other. Then, a blade was placed along the outer peripheral edge of the frame for the pellicle to cut and remove the excess pellicle film to prepare a pellicle.

A total of nine locations, one in the center of the pellicle, four locations 300 mm from the center when the diagonal line of the pellicle is drawn, and four locations 560 mm from the center, are set as the measurement target locations for film thickness measurement, and the film thickness of each of these locations is used. The film thickness variation was calculated by measurement. Moreover, the transmittance at the wavelength of 365 nm at that time was measured. In addition, a 6-inch pellicle was produced, and the focus was set to -0.1 as an exposure condition.
μm, exposure time 300msec, 305msec, 310msec, 315msec,
The exposure was evaluated by changing the value to 320 msec. Then, the in-plane range of the CD was measured.

[Example 2]
The frame for the pellicle is made of an aluminum alloy (5052) having a Young's modulus of 70 [GPa], and has an outer dimension of 900 mm × 750 mm, an outer corner R10 mm, and an inner corner R2 mm.
Except for using a frame with a long side width of 8 mm, a short side width of 7 mm, and a height of 5.2 mm.
A pellicle was prepared in the same manner as in Example 1. In addition, the calculation location of the film thickness variation of this pellicle is one in the center, four locations 345 mm from the center when the diagonal line of the pellicle is drawn, and 69 from the center.
The evaluation was performed in the same manner as in Example 1 except that the film thicknesses at 4 locations of 0 mm were measured at 9 locations in total.

[Example 3]
Cellulose Acetate Propionate (CAP), a polymer that constitutes a pellicle membrane
4 80-20, manufactured by Eastman Chemical Company) and ethyl lactate as a solvent were mixed to prepare a solution having a solid content concentration of 4% by mass. 0 with nitrogen in this solution
.. The pressure was increased to 01 MPa, and filtration was performed through a membrane filter having a diameter of 0.1 μm.
A film-forming substrate was physically polished, physically polished, then chemically polished, and washed with pure water. The film-forming substrate was heated and dried at 100 ° C. for 2 hours in a clean oven, and then cooled to room temperature. Next, the diameter of the substrate for film formation and the diameter of 5 cm into which hexamethyldisilazane 20 cc was introduced.
A polyethylene container with an open top was sealed in a clean metal box at room temperature for 30 minutes. After taking out the film-forming substrate, it was heated in a clean oven at 100 ° C. for 2 hours. The film-forming substrate prepared in this way is set in a closed cup type spin coater, about 300 g of the previously prepared polymer solution is supplied onto the glass substrate, and the film-forming substrate is 60 at 320 rpm.
It was rotated for 0 seconds. The film-forming substrate was placed on a hot plate at 60 ° C. for 15 minutes.
The solvent in the polymer solution was evaporated to make a main membrane.
Next, a fluororesin (Cytop, manufactured by Asahi Glass Co., Ltd.) was prepared as a polymer constituting the antireflection layer with a solution of Cytop CT-SLV (manufactured by Asahi Glass Co., Ltd.), which is a fluorosolvent, and the pore size was adjusted. Examples except that the filtrate was filtered with a 0.1 μm membrane filter, 5 cc of the filtrate was dropped onto the central layer of the main membrane, rotated at 320 rpm for 200 seconds, and then air-dried to form an antireflection layer. A pellicle was prepared with the same pellicle frame as in No. 1, and the same evaluation as in Example 1 was performed.

[Example 4]
The film-forming substrate of Example 3 was rotated at 100 rpm for 500 seconds, and the pellicle was produced in the same manner as in Example 3 except that the pellicle was produced using the same pellicle frame as in Example 2. Further, the same evaluation as in Example 1 was performed.

[Example 5]
Fluororesin (Cytop, manufactured by Asahi Glass Co., Ltd.), which is a polymer constituting the pellicle film, is diluted with a fluorine-based solvent (Cytop CT-SLV, manufactured by Asahi Glass Co., Ltd.) and then applied onto the film-forming substrate. , The film-forming substrate was rotated at 300 rpm for 600 sec. Then, a pellicle was prepared in the same manner as in Example 1 except that the solvent was completely removed by heating to 180 ° C. with a hot plate. Further, the same evaluation as in Example 1 was performed.

[Example 6]
Fluororesin (Cytop, manufactured by Asahi Glass Co., Ltd.), which is a polymer constituting the pellicle film, is diluted with a fluorine-based solvent (Cytop CT-SLV, manufactured by Asahi Glass Co., Ltd.) and then applied onto the film-forming substrate. , The film-forming substrate was rotated at 300 rpm for 400 seconds. Then, a pellicle was prepared in the same manner as in Example 1 except that the solvent was completely removed by heating to 180 ° C. with a hot plate. Further, the same evaluation as in Example 1 was performed.

[Comparative Example 1]
Cellulose Acetate Propionate (CAP), a polymer that constitutes a pellicle membrane
4 80-20, manufactured by Eastman Chemical Company) and ethyl lactate as a solvent were mixed to prepare a solution having a solid content concentration of 8% by mass. 0 with nitrogen in this solution
.. The pressure was increased to 01 MPa, and filtration was performed through a membrane filter having a diameter of 0.1 μm.

A film-forming substrate was physically polished, physically polished, then chemically polished, and washed with pure water. The film-forming substrate was heated and dried at 100 ° C. for 2 hours in a clean oven, and then cooled to room temperature. Next, the diameter of the substrate for film formation and the diameter of 5 cm into which hexamethyldisilazane 20 cc was introduced.
A polyethylene container with an open top was sealed in a clean metal box at room temperature for 30 minutes. After taking out the film-forming substrate, it was heated in a clean oven at 100 ° C. for 2 hours. The film-forming substrate prepared in this way is set in a closed cup type spin coater, about 300 g of the polymer solution prepared above is supplied onto the film-forming substrate, and the film-forming substrate is 90 at 280 rpm.
It was rotated for sec. The film-forming substrate was placed on a hot plate at 60 ° C. for 20 minutes, and the solvent in the polymer solution was evaporated to form a pellicle film on the film-forming substrate. Except for this, a pellicle was prepared in the same manner as in Example 1. Further, the evaluation was carried out in the same manner as in Example 1 except that the focus was set to −0.2 μm as the exposure condition.

[Comparative Example 2]
The frame for the pellicle is made of an aluminum alloy (5052) having a Young's modulus of 70 [GPa], and has an outer dimension of 900 mm × 750 mm, an outer corner R10 mm, and an inner corner R2 mm.
Except for using a frame with a long side width of 8 mm, a short side width of 7 mm, and a height of 5.2 mm.
A pellicle was prepared in the same manner as in Comparative Example 1. Also, as an exposure condition, focus is -0.2 μm.
The evaluation was carried out in the same manner as in Example 1 except that the above was performed.

[Reference Example 1]
As a reference example, an exposure evaluation without a pellicle was performed, and the in-plane range of the CD at that time was measured. The results are shown in the table.

The present invention prevents foreign matter from adhering to a photomask or reticle used in a lithography process when manufacturing a thin film transistor (TFT), a color filter (CF), or the like constituting an LSI or a flat panel display (FPD). Has industrial applicability as a large pellicle used for. In particular, the present invention uses the i-line (3) as an exposure light source.
It has industrial applicability as a large pellicle used in a lithography process using ultraviolet rays of 65 nm), j-line (313 nm), h-line (405 nm), or a mixture thereof. The pellicle of the present invention can be applied to a large photomask or reticle used in a photolithography process of a large color TFT LCD (thin film transistor liquid crystal display) capable of displaying high image quality and high definition, which has been developed in recent years.

[ Reference Example 5]
Fluororesin (Cytop, manufactured by Asahi Glass Co., Ltd.), which is a polymer constituting the pellicle film, is diluted with a fluorine-based solvent (Cytop CT-SLV, manufactured by Asahi Glass Co., Ltd.) and then applied onto the film-forming substrate. , The film-forming substrate was rotated at 300 rpm for 600 sec. Then, a pellicle was prepared in the same manner as in Example 1 except that the solvent was completely removed by heating to 180 ° C. with a hot plate. Further, the same evaluation as in Example 1 was performed.

[ Reference Example 6]
Fluororesin (Cytop, manufactured by Asahi Glass Co., Ltd.), which is a polymer constituting the pellicle film, is diluted with a fluorine-based solvent (Cytop CT-SLV, manufactured by Asahi Glass Co., Ltd.) and then applied onto the film-forming substrate. , The film-forming substrate was rotated at 300 rpm for 400 seconds. Then, a pellicle was prepared in the same manner as in Example 1 except that the solvent was completely removed by heating to 180 ° C. with a hot plate. Further, the same evaluation as in Example 1 was performed.

Claims (4)

A pellicle frame having an opening having a rectangular shape in a plan view having an area of 1000 cm ² or more, a pellicle film stretched and supported on one end surface of the pellicle frame so as to cover the opening, and the pellicle frame. A pellicle containing a mask adhesive on the other end face of the
A pellicle in which the film thickness of the pellicle film is 1.0 μm or more and 3.0 μm or less, and the film thickness variation in the pellicle film surface is 80 nm or less. The pellicle according to claim 1, wherein the transmittance of the pellicle film with respect to a wavelength of 365 nm is 95% or more. The pellicle according to claim 1 or 2, wherein the in-plane range of pattern dimensional accuracy in the L / S (vertical stripe pattern) transferred when exposed using the mask to which the pellicle is attached is 200 nm or less. The pellicle according to any one of claims 1 to 3, wherein the in-plane range of pattern dimensional accuracy in the contact hole to be transferred is 300 nm or less when exposed using the mask to which the pellicle is attached.

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