JPH11167198A - Pellicle for lithography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely and easily detect foreign matter on the inner face of a pellicle frame by specifying the surface roughness of the inner face of the pellicle frame and coating the inner face with an adhesive resin. SOLUTION: A pellicle film 2 is stretched on the top face of a pellicle frame 1 by way of an adhesive layer and the inner face of the pellicle frame 1 is coated with an adhesive. A sticky layer 3 is formed on the bottom of the pellicle frame 1 and a peelable releasing layer 4 is stuck on the bottom. At this time, the surface roughness of the inner face of the pellicle frame 1 is regulated to 0.3-0.9 μm Ra, 4.0-8.57 μm Rt and 0.3-1.1 μm RMS. The material of the pellicle film 2 is not particularly limited and nitrocellulose, cellulose acetate, cellulose propionate or a non-crystalline fluorine-contg. polymer may be used. The material of the adhesive layer is, e.g. an acrylic resin adhesive, an epoxy resin adhesive, a silicone resin adhesive or a fluorine-contg. polymer such as a fluorine- contg. silicone adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LSI,
The present invention relates to a pellicle for lithography (hereinafter, referred to as a pellicle) that prevents dust from adhering to a mask used in a lithography process when manufacturing a semiconductor device such as a liquid crystal display panel.

[0002]

2. Description of the Related Art When manufacturing semiconductor devices and liquid crystal display panels,
A mask (exposure original plate) is used to irradiate light to transfer a pattern onto a substrate. If dust adheres to this mask, the light absorbs or bends due to the dust, resulting in deformation of the transferred pattern, roughening of the pattern edges, and blacking of the base, resulting in product dimensions, quality,
The appearance and the like are deteriorated. Therefore, the pattern transfer operation is usually performed in a clean clean room. However, even in a clean room atmosphere,
It is actually difficult to keep the mask clean at all times. Therefore, by attaching a pellicle having good light transmittance to the surface of the mask, dust is prevented from adhering to the mask. That is, by using a pellicle,
Dust adheres to the pellicle surface and does not directly adhere to the mask surface. Therefore, if the focus is set on the pattern of the mask at the time of the lithography process, adverse effects on the transfer due to dust will not be observed.

As shown in FIG. 1, the basic structure of a pellicle that plays such a role is generally a black pellicle frame 1 made of aluminum, stainless steel, polystyrene, or the like, and an adhesive layer ( (Not shown), a transparent pellicle film 2 made of nitrocellulose, cellulose acetate or the like and having excellent light transmittance, and an adhesive layer provided at the lower end of the pellicle frame 1 to be mounted on a mask. 3 and a release layer (separator) 4 for protecting the adhesive layer 3. To stretch the pellicle film 2 on the upper end surface of the pellicle frame 1, a good solvent for the pellicle film 2 is applied to the pellicle frame 1 and air-dried (Japanese Patent Laid-Open No. 58-2190).
No. 23) or a method of bonding with an adhesive made of acrylic resin, epoxy resin or the like (US Pat. No. 486140).
No. 2, Japanese Patent Publication No. 63-27,702). As described above, since the pellicle is used in the lithography process, its constituent members are required to have high cleanliness. In particular, if foreign matter adheres to the inner surface of the pellicle frame, the possibility of contaminating the reticle surface increases, so high cleanliness is required. In general, the inner surface of the pellicle frame is coated with an adhesive resin to a thickness of about 10 to 50 μm so that foreign substances attached to the inner surface do not fall off.
As a result, the attached foreign matter is retained,
Depending on the size of foreign matter and the state of adhesion, it may not be completely retained. Therefore, at the time of manufacturing the pellicle or at the time of the acceptance inspection before use, the attached foreign matter inspection on the inner surface of the pellicle frame is performed.

[0004]

However, the surface of the pellicle frame is generally roughened by sand blasting or chemical polishing to make it matt. Therefore, if the inner surface of the pellicle frame is coated with an adhesive resin, this resin enters the roughened surface and diffuses the inspection light. Many foreign substances seem to adhere to the inner surface of the pellicle frame, or foreign substances that should be detected are overlooked, resulting in a decrease in yield.

Accordingly, the present invention provides a pellicle capable of suppressing irregular reflection of light by coating an inner surface of a pellicle frame with an adhesive resin and reliably and easily detecting foreign matter on the inner surface of the pellicle frame. With the goal.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the surface roughness of the inner surface of the pellicle frame has been adjusted to a predetermined range, thereby coating the adhesive resin. It has been found that irregular reflection of inspection light can be suppressed on the inner surface of the pellicle frame, and the present invention has been completed based on this finding. That is, in the present invention, the surface roughness of the inner surface of the pellicle frame is Ra 0.3 to 0.5.
9 μm, Rt 4.0-8.5 μm, RMS 0.3-1.
A pellicle for lithography, wherein the pellicle is in a range of 1 μm and the inner surface of the pellicle frame is coated with an adhesive resin.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the pellicle of the present invention has an adhesive layer (not shown) on an upper end surface of a pellicle frame 1.
A pellicle film 2 is stretched through the pellicle frame, and an adhesive is coated on the inner surface of the pellicle frame 1. Usually, an adhesive layer 3 is further formed at a lower portion of the pellicle frame 1, and the lower end surface thereof is peelable. The proper release layer 4 is stuck.

The material of the pellicle frame 1 is not particularly limited, and examples thereof include conventionally used anodized aluminum materials, stainless steel, polyacetal, polycarbonate, PMMA, acrylic resin and other resins, and blue glass. . The surface of the pellicle frame 1 is usually roughened,
The method is not limited, and examples include sandblasting and chemical polishing. For example, when an aluminum material is used, a method is known in which blasting is performed using carborundum, glass beads, or the like, and the surface is roughened by chemical polishing using NaOH or the like.

[0009] The inner surface of the pellicle frame 1 is coated with an adhesive resin in order to adhere and hold foreign matter and to prevent generation of dust. Examples of the adhesive resin include a silicone adhesive and an acrylic adhesive. Further, the coating has a thickness of 10 to 50 μm.

In the present invention, when the surface roughness of the inner surface of the pellicle frame 1 is measured by a stylus type surface roughness meter, Ra 0.3 to
0.9 μm, Rt 4.0 to 8.5 μm, RMS 0.3 to
The range is 1.1 μm. When the surface roughness of the inner surface of the pellicle frame 1 is smaller than the value specified in the present invention, if the inner surface of the pellicle frame is coated with an adhesive resin, the resin that has entered the unevenness of the inner surface surface fills the unevenness. Although the inspection light is not irregularly reflected and is not erroneously recognized as a foreign substance, since the reflected light on the inner surface of the pellicle frame increases, for example, when the foreign substance on the pellicle film 2 is inspected by a laser scattering type inspection apparatus, The laser light may be reflected on the inner surface of the pellicle frame and may be mistaken as if a foreign substance exists on the pellicle film. Meanwhile, pellicle frame 1
When the surface roughness of the inner surface is larger than the value specified in the present invention, the amount of light scattered on the inner surface of the pellicle frame can be reduced. The resin that has entered the irregularities on the side surface irregularly reflects the inspection light, and it is erroneously recognized that many foreign substances are attached to the inner side surface, which makes not only the inspection difficult, but also the foreign substance actually attached. If the pellicle is used, the foreign matter falls off and adheres to the reticle surface when the pellicle is used, thereby lowering the yield.

The material of the pellicle film 2 is not particularly limited, and examples thereof include conventionally used nitrocellulose, cellulose acetate, cellulose propionate, and an amorphous fluoropolymer. As an amorphous fluoropolymer,
Examples include Cytop (trade name, manufactured by Asahi Glass Co., Ltd.) and Teflon AF (trade name, manufactured by DuPont). These polymers may be used by dissolving them in a fluorinated solvent or the like as necessary at the time of producing the pellicle film.

The material of the adhesive layer may be appropriately selected from those conventionally used. Fluoropolymers such as acrylic resin adhesives, epoxy resin adhesives, silicone resin adhesives, and fluorine-containing silicone adhesives can be used. And a fluorine-based polymer is particularly preferable. Examples of the fluorine-based polymer include a fluorine-based polymer CT69 (trade name, manufactured by Asahi Glass Co., Ltd.). The adhesive layer 3 may be formed using a double-sided adhesive tape, a silicone resin adhesive, an acrylic adhesive, or the like. As for the material of the release layer 4, a generally used silicone release agent, a fluorine-modified silicone release agent, or the like may be selected. The size of each pellicle component is not particularly limited, and may be the same as a normal pellicle.

In order to manufacture the pellicle of the present invention, a pellicle film 2 is stretched through an adhesive layer on an upper end surface of a pellicle frame 1 having an inner surface coated with an adhesive resin by an ordinary method. The adhesive layer 3 may be formed on the lower end surface of the pellicle frame 1 and the release layer 4 may be attached to the lower end surface of the adhesive layer 3 so as to be peelable. Here, the adhesive layer can be formed by diluting the adhesive with a solvent, if necessary, applying the diluted adhesive to the upper end surface of the pellicle frame 1, heating, drying, and curing. In this case, examples of the method of applying the adhesive include brush coating, spraying, and a method using an automatic dispenser.

[0014]

Next, the present invention will be described in more detail with reference to examples. Note that the present invention is not limited to the following embodiments.

(Embodiment 1) First, as a pellicle frame,
Frame outer dimensions 100mm x 100mm x 6mm, frame thickness 2mm
Was prepared. After the surface was washed, the surface was roughened by using glass beads having a particle diameter of 90 μm for 10 minutes using a sandblasting device with a discharge pressure of 1.5 kg. Next, this was treated in an NaOH treatment bath for 10 seconds, washed, and then subjected to anodizing, black dyeing, and sealing to form a black oxide film on the surface. When the surface of the finished frame was measured with a surface roughness meter surf coder (trade name, manufactured by Kosaka Laboratories), Ra 0.45 μm was obtained.
m, Rt 4.5 μm, and RMS 0.45 μm. The aluminum frame was cleaned using pure water and an ultrasonic cleaning device together. Next, this frame was coated with a silicone-based pressure-sensitive adhesive at 10 μm using a spray coating device.
Next, Teflon AF1600 (trade name, manufactured by DuPont, USA) was dissolved in a fluorinated solvent Florinert FC-75 (trade name, manufactured by 3M, USA) to prepare a solution having a concentration of 8%. Next, with this solution, a diameter of 200 mm,
A transparent film having a film thickness of 0.8 μm was formed on a mirror-polished silicon substrate surface having a thickness of 600 μm using a spin coater. Next, an outer dimension of 200 mm x 200 m
A frame having a width of 5 mm and a width of 5 mm was adhered using an epoxy adhesive Aralditrapid (trade name, manufactured by Showa Polymer Co., Ltd.) and peeled off in water. Next, a Teflon A film formed from the aluminum alloy frame prepared as described above using an epoxy-based adhesive Aralditrapid (same as above).
It adhered to the film surface of F1600. The two frames were attached to a fixing jig with the bonding surface of the pellicle frame facing upward and fixed so as not to be relatively displaced. Next, the frame outside the pellicle frame was pulled up and fixed, and a tension of 0.5 g / cm was applied to the film portion outside the pellicle frame. Separately, a stainless steel cutter having a thickness of 0.25 mm was attached to a scalar robot as a film cutting instrument. Using a tube dispenser for this cutter, Florinert FC
75 (same as above) was dropped at 10 μl / min, and the unnecessary film portion outside the pellicle frame was cut and removed while moving the cutter along the periphery of the adhesive portion on the pellicle frame.
Next, the unnecessary film portion was removed, and the inner surface of the obtained pellicle was inspected while illuminating it with a halogen lamp. As a result, there was no foreign matter on the surface, and there was no irregular reflection of light on the frame surface. . Therefore, polystyrene standard particles having a particle diameter of 1.0 μm were attached to the inner surface of the frame. When this was similarly inspected while illuminating with a halogen lamp, it was confirmed that it was easily adhered. In addition, when a foreign substance on the pellicle film was inspected using a laser scattering foreign substance inspection device,
There was no erroneous detection due to scattered light from the frame.

(Comparative Example 1) First, as a pellicle frame,
Frame outer dimensions 100mm x 100mm x 6mm, frame thickness 2mm
Was prepared. After the surface was washed, the surface was roughened by using glass beads having a particle diameter of 90 μm for 10 minutes using a sandblasting device with a discharge pressure of 1.5 kg. Next, this was treated in an NaOH treatment bath for 10 seconds, washed, and then subjected to anodizing, black dyeing, and sealing to form a black oxide film on the surface. Surface finisher surf coder (same as above)
When measured at, Ra 0.9 μm, Rt 9.1 μm
m, RMS 1.2 μm. The aluminum frame was cleaned using pure water and an ultrasonic cleaning device together. Next, this frame was coated with a silicone-based pressure-sensitive adhesive at 10 μm using a spray coating device. Next, Teflon A
F1600 (same as above) with fluorinated solvent Fluorinert FC
-75 (same as above) to prepare an 8% concentration solution. Next, a diameter of 200 mm and a thickness of 60
A 0.8 μm thick transparent film was formed on a 0 μm mirror-polished silicon substrate surface using a spin coater. Next, an outer dimension of 200 mm × 200 mm × 5
A frame having a width of 5 mm and a thickness of 5 mm was adhered using an epoxy-based adhesive Aralditrapid (the same as above) and peeled off in water.
Next, the aluminum alloy frame prepared as described above was attached to the epoxy-based adhesive Aralditrapid (same as above).
Was adhered to the film surface of Teflon AF1600 formed by using the method described above. The two frames were attached to a fixing jig with the bonding surface of the pellicle frame facing upward and fixed so as not to be relatively displaced. Next, the frame outside the pellicle frame was pulled up and fixed, and a tension of 0.5 g / cm was applied to the film portion outside the pellicle frame. Separately, a stainless steel cutter having a thickness of 0.25 mm was attached to a scalar robot as a film cutting instrument. Using a tube type dispenser for this cutter, Florinert FC75 (same as above) was added at 10 μm / min.
While dropping, the unnecessary film portion outside the pellicle frame was cut and removed while moving the cutter along the periphery of the adhesive portion on the pellicle frame. Next, the unnecessary film portion was removed, and the inner surface of the obtained pellicle was inspected while illuminating it with a halogen lamp. Then, the inner surface of the pellicle was examined using a stereomicroscope, but no adhering foreign matter was found. Therefore, this was found to be irregular reflection of light on the surface of the frame. Here, standard polystyrene particles having a particle diameter of 1.0 μm were attached to the inner surface of the frame. When this was similarly inspected while illuminating with a halogen lamp, it could not be distinguished from many other scattered lights. Further, when a foreign substance inspection on the pellicle film was performed using the laser scattering foreign substance inspection apparatus, no erroneous detection due to scattered light from the frame was found.

(Embodiment 2) First, as a pellicle frame,
Frame outer dimensions 100mm x 100mm x 6mm, frame thickness 2mm
Was prepared. After the surface was washed, the surface was roughened by using glass beads having a particle size of 90 μm for 10 minutes using a sand blasting apparatus having a discharge pressure of 2.0 kg. Next, this was treated in an NaOH treatment bath for 10 seconds, washed, and then subjected to anodizing, black dyeing, and sealing to form a black oxide film on the surface. Surface finisher surf coder (same as above)
When measured at, Ra 0.5 μm, Rt 5.1 μ
m, RMS 0.5 μm. The aluminum frame was cleaned using pure water and an ultrasonic cleaning device together. Next, this frame was coated with a silicone-based pressure-sensitive adhesive at 10 μm using a spray coating device. Next, Teflon A
F1600 (same as above) with fluorinated solvent Fluorinert FC
-75 (same as above) to prepare an 8% concentration solution. Next, a diameter of 200 mm and a thickness of 60
A 0.8 μm thick transparent film was formed on a 0 μm mirror-polished silicon substrate surface using a spin coater. Next, an outer dimension of 200 mm × 200 mm × 5
A frame having a width of 5 mm and a thickness of 5 mm was adhered using an epoxy-based adhesive Aralditrapid (the same as above) and peeled off in water.
Next, the aluminum alloy frame prepared as described above was used as an epoxy-based adhesive
Was adhered to the film surface of Teflon AF1600 formed by using the method described above. The two frames were attached to a fixing jig with the bonding surface of the pellicle frame facing upward and fixed so as not to be relatively displaced. Next, the frame outside the pellicle frame was pulled up and fixed, and a tension of 0.5 g / cm was applied to the film portion outside the pellicle frame. Separately, a stainless steel cutter having a thickness of 0.25 mm was attached to a scalar robot as a film cutting instrument. Using a tube type dispenser for this cutter, Florinert FC75 (same as above) was added at 10 μ / min
While dropping, the unnecessary film portion outside the pellicle frame was cut and removed while moving the cutter along the periphery of the adhesive portion on the pellicle frame. Next, the unnecessary film portion was removed, and the inner surface of the obtained pellicle was inspected while illuminating with a halogen lamp. . Therefore, polystyrene standard particles having a particle diameter of 1.0 μm were attached to the inner surface of the frame. When this was similarly inspected while illuminating with a halogen lamp, it was confirmed that it was easily adhered. Further, when a foreign substance inspection on the pellicle film was performed using the laser scattering foreign substance inspection apparatus, no erroneous detection due to scattered light from the frame was found.

Comparative Example 2 First, as a pellicle frame,
Frame outer dimensions 100mm x 100mm x 6mm, frame thickness 2mm
Was prepared. After washing the surface, the surface was roughened by using glass beads having a particle diameter of 40 μm for 10 minutes using a sand blasting apparatus having a discharge pressure of 1.5 kg. Next, this was treated in an NaOH treatment bath for 10 seconds, washed, and then subjected to anodizing, black dyeing, and sealing to form a black oxide film on the surface. Surface finisher surf coder (same as above)
When measured at, Ra 0.2 μm, Rt 3.0 μ
m, RMS 0.2 μm. The aluminum frame was cleaned using pure water and an ultrasonic cleaning device together. Next, this frame was coated with a silicone-based pressure-sensitive adhesive at 10 μm using a spray coating device. Next, Teflon A
F1600 (same as above) with fluorinated solvent Fluorinert FC
-75 (same as above) to prepare an 8% concentration solution. Next, a diameter of 200 mm and a thickness of 60
A 0.8 μm thick transparent film was formed on a 0 μm mirror-polished silicon substrate surface using a spin coater. Next, an outer dimension of 200 mm × 200 mm × 5
A frame having a width of 5 mm and a thickness of 5 mm was adhered using an epoxy-based adhesive Aralditrapid (the same as above) and peeled off in water.
Next, the aluminum alloy frame prepared as described above was attached to the epoxy-based adhesive Aralditrapid (same as above).
Was adhered to the film surface of Teflon AF1600 formed by using the method described above. The two frames were attached to a fixing jig with the bonding surface of the pellicle frame facing upward and fixed so as not to be relatively displaced. Next, the frame outside the pellicle frame was pulled up and fixed, and a tension of 0.5 g / cm was applied to the film portion outside the pellicle frame. Separately, a stainless steel cutter having a thickness of 0.25 mm was attached to a scalar robot as a film cutting instrument. Using a tube type dispenser for this cutter, Florinert FC75 (same as above) was added at 10 μm / min.
While dropping, the unnecessary film portion outside the pellicle frame was cut and removed while moving the cutter along the periphery of the adhesive portion on the pellicle frame. Next, the unnecessary film portion was removed, and the inner surface of the obtained pellicle was inspected while illuminating it with a halogen lamp. As a result, there was no foreign matter on the surface. Therefore, polystyrene standard particles having a particle size of 1.0 μm were attached to the inner surface of the frame. When this was similarly inspected while illuminating with a halogen lamp, it could be easily detected. Further, when a foreign substance inspection on the pellicle film was performed using the laser scattering foreign substance inspection apparatus, erroneous detection due to scattered light from the frame appeared on the film near the frame.

[0019]

The pellicle of the present invention can reliably and easily detect foreign matter on the inner surface of the pellicle frame, thereby preventing a decrease in yield.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an example of a pellicle.

[Explanation of symbols]

 Reference Signs List 1 pellicle frame 2 pellicle film 3 adhesive layer 4 release layer

Claims (1)

[Claims] The surface roughness of the inner surface of the pellicle frame is Ra.
0.3-0.9 μm, Rt 4.0-8.5 μm, RMS
A pellicle for lithography, wherein the pellicle is in the range of 0.3 to 1.1 [mu] m and the inner surface of the pellicle frame is coated with an adhesive resin.