JP2003167327A - Pellicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pellicle that prevents deterioration of an adhesive and a sealant due to cleaning light and can retain its function over a prolonged period of time. <P>SOLUTION: The pellicle 1 obtained by bonding a pellicle plate 2 comprising synthetic quartz glass to the opening of a pellicle frame 5 with an adhesive 4, is characterized in that the pellicle plate 2 has a first light shielding body 3 for protecting the adhesive 4 from irradiation with ultraviolet light and the pellicle frame 5 comprises quartz glass and has second light shielding bodies on its top surface and bottom surface and/or its outer surface and inner surface. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an LSI and a VLSI.
The present invention relates to a pellicle suitable for an exposure method using a light having a wavelength of 220 nm or less and a method of using the pellicle, which is used when manufacturing a semiconductor or a liquid crystal display.

[0002]

2. Description of the Related Art Conventionally, in the manufacture of semiconductors such as LSI and VLSI, or liquid crystal display devices, patterning is performed by irradiating a semiconductor wafer or liquid crystal display plate with light having a wavelength of 240 nm or more through a mask (mask or reticle). ing. In this case, if dust adheres to the pattern formation surface of the mask, the dust absorbs, reflects, or bends the exposure light.
The quality and appearance will be impaired. Therefore, although the exposure work is performed in the clean room, it is difficult to keep the mask clean.

Therefore, in order to prevent dust from adhering to the mask, it is common to perform an exposure operation using a pellicle. Specifically, FIG. 6 is a perspective view showing a state in which a conventional pellicle is mounted on a mask, and FIG. 7 is a cross-sectional view taken along the line AA of FIG. 6, but the pellicle 11 includes a pellicle film 12 that transmits exposure light. The pellicle frame 15 is bonded to the opening of the pellicle frame 15 with the adhesive 4, and the pellicle frame 15 is attached to the mask 7 by the sealing material 6 during the exposure operation. The mask 7 having such a pellicle 1 mounted thereon can be used semipermanently as long as the pellicle film 12 or the pellicle frame 15 is not damaged, because the transmittance is not reduced and dust does not enter.

On the other hand, the exposure light used in the manufacture of semiconductors such as LSI and VLSI is becoming shorter in wavelength to meet the demand for miniaturization, and today, exposure light having a wavelength of 220 nm or less such as F ₂ laser is used. The technology of using is devised.

Conventionally, as the pellicle film, an organic resin film made of nitrocellulose or fluororesin having a thickness of several nm to several μm is used. However, in a pellicle using such an organic film, when the wavelength used for improving the exposure accuracy becomes shorter, the optical energy is large, so the organic component is decomposed and used in actual exposure. It does not have enough durability for the number of shots with energy, in other words, the usage time.

Therefore, in recent years, it has been investigated to use a synthetic quartz glass processed into a thin plate as a pellicle film instead of the organic resin film (in this specification, a pellicle film made of synthetic quartz glass is referred to as an organic pellicle film). It is called a pellicle plate to distinguish it from a resin-based pellicle film). This synthetic quartz glass is obtained, for example, by reacting a silicon source and an oxygen source in a gas phase to grow a porous silicon oxide called soot, and sintering the porous material to obtain substantially only silicon oxide. It is a glass. In a pellicle plate made of this synthetic quartz glass, in an exposure system using a wavelength of 157.6 nm or less,
In order to improve the transmission efficiency, it is preferable to apply an antireflection film on one side or both sides.

[0007]

By the way, in the mask used for these exposure lights, the organic gas existing in the clean room at the time of exposure adheres and the light transmittance may decrease. The mask is stored in a case made of synthetic resin such as polyacrylate, polystyrene, polypropylene, polyethylene, polycarbonate, and ABS resin during storage and transportation. However, it has also been found that an organic gas is generated from this case and adheres to the surface of the housed mask to reduce the light transmittance.

Therefore, it is common to clean the mask before exposure, and the applicant of the present invention uses Xe ₂ as the cleaning method.
A technique has been proposed (PCT / JP00 / 01869) for decomposing and removing organic substances by irradiating ultraviolet rays (hereinafter referred to as “cleaning light”) such as excimer lamps and F ₂ lasers.

Therefore, the pellicle plate is required to have sufficient durability (light resistance) against such cleaning light, but at the same time, the adhesive for adhering the pellicle plate and the pellicle frame also has cleaning light. The same light resistance is required for the adhesive as well. However, conventionally, as an adhesive,
Polybutene resin, acrylic resin or epoxy resin adhesives and silicone adhesives are used, but none of the adhesive materials have sufficient light resistance, and the adhesive strength increases as the number of washing light irradiations increases. And the pellicle plate 2 is separated from the pellicle frame 4 to form a gap and the dustproof function is not exerted, or the deteriorated adhesive becomes new dust and adheres to the pattern forming surface of the mask. Will cause problems.

When a pellicle using synthetic quartz glass as a pellicle plate is actually used in an exposure process, the synthetic quartz glass itself absorbs light energy and has heat, so that the pellicle plate expands. Similarly, the frame itself expands by absorbing heat of its own light energy and conducting heat from the surroundings. At this time, the metal conventionally used as the frame material, such as aluminum or titanium, has a coefficient of thermal expansion different from that of the synthetic quartz glass, so that the pellicle plate is distorted and stress is generated, which causes a large birefringence. Become. Therefore, in order to prevent deterioration of the image forming property due to mechanical deflection and birefringence, it has been proposed to use quartz glass as a frame material, which has a coefficient of thermal expansion equivalent to that of the pellicle plate.

In the pellicle frame made of quartz glass, it is desirable that the inner surface and the outer surface of the frame be mirror-finished. That is, when the inner surface and the outer surface of the frame are finished in a frosted glass state by, for example, end milling, particles are held in the fine irregularities on the surface of the frosted glass, or the exposure of the glass itself is broken due to crushing or the like. This is because foreign matter may adhere to the mask surface. However, since the quartz glass frame whose inner and outer surfaces are mirror-finished transmits the above-mentioned cleaning light, the sealing material such as a silicone adhesive between the pellicle frame and the mask is likely to deteriorate due to the cleaning. Further, the adhesive between the pellicle frame and the pellicle plate and the sealing material between the pellicle frame and the mask are easily deteriorated by stray light generated by the reflection of the cleaning light on the interface between the mask and the pellicle.

The present invention has been made in view of such a situation, and the deterioration of the adhesive for adhering the pellicle plate and the pellicle frame due to cleaning light and the sealing material interposed between the pellicle frame and the mask. An object is to provide a pellicle that is prevented from deterioration.

[0013]

To achieve the above object, the present invention provides a pellicle obtained by bonding a pellicle plate made of synthetic quartz glass to an opening of a frame-shaped pellicle frame with an adhesive. The pellicle plate is provided with a first light shield for shielding the adhesive from ultraviolet light irradiation, the pellicle frame is made of quartz glass, and the second light shield is provided on the upper and lower surfaces of the pellicle frame. And a pellicle plate made of synthetic quartz glass adhered to an opening of a frame-shaped pellicle frame with an adhesive, the first pellicle for shielding the adhesive from ultraviolet light irradiation. The pellicle board is provided with a light shield, and the pellicle frame is made of quartz glass. Providing a pellicle characterized by having a second light shield to frame the peripheral surface.

Particularly in the above pellicle, it is preferable that the light shield is made of metal or metal oxide.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 is a perspective view showing an embodiment of the pellicle of the present invention mounted on a mask.
FIG. 2 is a sectional view taken along line AA of FIG. FIG. 3 is a cross-sectional view showing another embodiment of the pellicle of the present invention along the AA cross section of FIG.

As shown in FIGS. 1 and 2, the pellicle 1
Attach the pellicle plate 2 to the pellicle frame 5 with the adhesive 4.
The basic structure is formed by adhering to the opening. The pellicle plate 2 is a thin plate of synthetic quartz glass so that it can handle exposure light having a wavelength of 220 nm or less.
As described above, the synthetic quartz glass is substantially silicon oxide obtained by, for example, reacting a silicon source and an oxygen source in a gas phase to grow a porous silicon oxide called soot and sintering the soot. It is a glass consisting of only.

As the pellicle frame 5, quartz glass is used. As this quartz glass, the pellicle plate 2
Any material may be used as long as it has substantially the same thermal expansion coefficient as that of the synthetic quartz glass which is the material of (1), and is not necessarily synthetic quartz glass, and fused quartz glass can also be used. Further, as the adhesive 4, a polybutene resin, an acrylic resin, an epoxy resin adhesive, a silicone adhesive, or the like can be used as in the conventional case.

In addition to the above-mentioned basic structure, the pellicle 1 of the present invention covers the part where the pellicle plate 2 and the pellicle frame 4 are bonded, that is, the part to which the adhesive 4 is applied, on the pellicle plate 2. The first light shield 3 is formed on the.

There are no particular restrictions on the material or form of the first light shield 3 as long as it does not transmit cleaning light and has sufficient light resistance. The product can be used in the form of a film or a plate. The type of metal is not particularly limited, but chromium, aluminum, iron, copper, or an alloy thereof is preferable for reasons of light resistance and light shielding properties. When using a metal plate, aluminum, iron,
A metal or a metal alloy that can be precisely processed such as copper can be used. In addition, in this invention, a metal foil is also included as this metal plate. When a metal oxide film is used, a film of chromium oxide (CrO _x ), silica (SiO ₂ ), alumina (Al ₂ O ₃ ) or the like is preferable for reasons of light resistance and light shielding properties. Although the film thickness depends on the material of the film,
It has only to have a sufficient light-shielding property with respect to ultraviolet light of 20 nm or less, and 50 nm or more, preferably 50 nm to 100
It may be 0 nm, particularly preferably 100 to 1000 nm.

The first light shield 3 can be provided on the pellicle plate 2 as shown in FIG. 2, or can be bonded between the pellicle plate 2 and the pellicle frame 5 as shown in FIG. It can also be provided so as to cover the agent 4.

Further, in order to form the above-mentioned metal film and metal oxide film, known means such as sputtering method,
A vapor deposition method, a CVD method, a printing method or the like may be appropriately selected in consideration of the type of coating material and the adhesiveness with the pellicle plate 2. On the other hand, in the case of a metal plate, it may be fixed by using an appropriate adhesive between the surface of the pellicle plate 2 and the pellicle plate 2 and the pellicle frame 5.

Each of the above pellicles 1 is mounted on the mask 7 via the sealing material 6 applied to the lower surface of the pellicle frame 5 as in the conventional case.

Further, in the present invention, the second light shielding film 9
Are provided on the upper surface and the lower surface of the pellicle frame, and / or on the outer peripheral surface and the inner peripheral surface of the frame. 2 and 3 show an example in which the second light shielding film 9 is provided only on the frame upper surface and the frame lower surface of the pellicle frame.

FIG. 4 is a perspective view showing a case where the second light-shielding film 9 is provided only on the frame upper surface and the frame lower surface of the pellicle frame, and FIG.
FIG. 3 is a perspective view showing a case where the above is provided only on the outer peripheral surface and the inner peripheral surface of the frame of the pellicle frame. Specifically, in FIG. 4, the second light-shielding film 9 is provided on the frame upper surface 5a and the frame lower surface 5b of the pellicle frame 5, and in FIG. Inner surface 5 of frame
The second light-shielding film 9 is provided on d. The second light shield may be provided on the entire surface of the pellicle frame by combining the embodiment of FIG. 4 and the embodiment of FIG.

The second light-shielding film 9 can be provided in the same material and form as the first light-shielding film 3 by the same method. Both light shielding films may be provided with the same material and form, or may be provided with different material forms.

In the present invention, by combining the first light-shielding film and the second light-shielding film, the cleaning light and its stray light cause the adhesive between the pellicle frame and the pellicle plate, and the pellicle frame and the mask. It is possible to prevent them from reaching the sealing material between them, and to suppress their deterioration.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples. 152 m of synthetic quartz glass obtained by a known method
A blank of m × 152 mm × 5.2 mm was chamfered by a commercially available NC chamfering machine so as to have a C of 0.3 to 0.7. Next, in order to stop the progress of cracks due to cutting and cracks due to chamfering, the pieces were immersed in a 5 mass% HF solution.

Then, this quartz glass plate material was used as a polishing agent in a FO # 1200 (trade name, manufactured by Fujimi Corporation) using a 20B double-sided lapping machine manufactured by Speedfam.
Using a slurry obtained by suspending 10 to 12% by mass of filtered water, lapping was performed until the thickness became 5.05 mm. Furthermore, the same etching treatment as described above was performed on the synthetic quartz glass plate material after the lapping.

Subsequently, this quartz glass plate material was polished with a slurry mainly composed of cerium oxide and a polyurethane pad using a 20B double-side polishing machine manufactured by Speed Fam Co., and a 5.00 mm thick pellicle frame plate material was prepared.
I got one.

The flatness of this plate material was measured with a laser interference flatness measuring instrument, FM200, manufactured by Tropel Co., Ltd. One surface was 0.48 to 0.65 μm and the other surface was 0.44 to 0.45 μm. The result was 0.68 μm. Furthermore, when the parallelism of these samples was measured, all the plate materials were 2.00 μm or less.

Based on this result, using an end mill from the plate material, the outer dimensions are 149 mm × 122 mm and the inner dimensions are 145 mm × 1.
A pellicle frame having a rectangular frame body of 18 mm and rounded corners with a radius of 5 mm was prepared. After that, the inner peripheral surface and the outer peripheral surface of the frame, excluding the adhesive surface with the mask and the adhesive surface with the pellicle plate, which have already been polished, were mirror-finished by buffing.

Next, a metal chromium film was formed on the entire surface of this frame by sputtering to a thickness of 100 nm to form a pellicle frame.

Further, the pellicle plate has a thickness of 0.3 mm.
Using a polished synthetic quartz glass plate, adhere it to the pellicle frame using a polybutene adhesive, and then form a Cr film of 100 nm thickness by sputtering on the surface of the synthetic quartz glass plate with the same width as the pellicle frame. It was created.

The pellicle obtained has excellent light-shielding properties, and prevents the cleaning light and its stray light from reaching the adhesive between the pellicle frame and the pellicle plate and the sealing material between the pellicle frame and the mask. It is possible to prevent and suppress these deteriorations.

[0035]

According to the present invention, with respect to a pellicle having a synthetic quartz glass pellicle plate and a quartz glass pellicle frame, it is possible to prevent deterioration of the adhesive or sealing material due to cleaning light and maintain the function of the pellicle for a long period of time. Can be provided.

Specifically, the present invention prevents the adhesive for adhering the pellicle plate and the pellicle frame due to the cleaning light and the sealant between the pellicle frame and the mask from being deteriorated by the light shielding member. It is possible to prevent the deteriorated product of the sealing material from becoming a foreign matter and adhering to the mask, and to prevent the pellicle plate from peeling off, so that the function of the pellicle can be favorably maintained for a long time. The effect of preventing the deterioration of such adhesives and sealing materials is particularly the wavelength of 220 nm, which will be the mainstream of fine processing in the future.
It appears as a remarkable effect in the following technique using exposure light.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a pellicle of the present invention mounted on a mask.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view showing a second embodiment of the pellicle of the present invention along the AA cross section in FIG. 1.

FIG. 4 is a perspective view showing an example of a pellicle frame used in the present invention.

FIG. 5 is a perspective view showing another example of the pellicle frame used in the present invention.

FIG. 6 is a perspective view showing a conventional pellicle mounted on a mask.

7 is a cross-sectional view taken along the line AA in FIG.

[Explanation of symbols]

1: Pellicle 2: Pellicle board 3: Light shield 4: Adhesive 5: Pellicle frame 6: Seal material 7: Mask

Claims (5)

[Claims] 1. A pellicle obtained by adhering a pellicle plate made of synthetic quartz glass to an opening of a frame-shaped pellicle frame with an adhesive, wherein a first light shield for shielding the adhesive from ultraviolet light irradiation is provided. While preparing for the pellicle board,
The pellicle frame is made of quartz glass, and has a second light shield on the frame upper surface and the frame lower surface of the pellicle frame. 2. A pellicle formed by adhering a pellicle plate made of synthetic quartz glass to an opening of a frame-shaped pellicle frame with an adhesive, and a first light shield for shielding the adhesive from ultraviolet light irradiation. While preparing for the pellicle board,
The pellicle frame is made of quartz glass, and the pellicle frame has a second outer surface and a second inner surface.
A pellicle having a light-shielding body. 3. The pellicle according to claim 1, wherein the second light shield is made of metal or metal oxide. 4. The second light shield is chromium, aluminum,
4. At least one metal selected from the group consisting of iron, copper and alloys thereof.
Pellicle as described. 5. The pellicle according to claim 3, wherein the second light shield is made of at least one metal oxide selected from the group consisting of chromium oxide, silica and alumina.