JP2001312047A - Pellicle and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pellicle with a pellicle plate made of synthetic quartz glass and having such a degree of precision as <±0.3 μm/150 mm unevenness in thickness necessary for a pellicle plate. SOLUTION: The objective method for producing a pellicle includes a step for producing a pellicle plate by polishing a synthetic quartz glass plate whose dimensions are larger than those of a pellicle frame by >=10 mm and then cutting the polished plate to prescribed dimensions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pellicle to be mounted on a mask or a reticle used in an integrated circuit manufacturing process (hereinafter, both masks are collectively referred to as a mask) for the purpose of preventing foreign matter from adhering, and a method of manufacturing the pellicle. .

[0002]

2. Description of the Related Art In an optical lithography process used in an integrated circuit manufacturing process, a pattern is formed by exposing a semiconductor wafer coated with a resist material to light.
If a scratch or foreign matter is present on the mask used at this time, the scratch or foreign matter along with the pattern is transferred onto the wafer, causing a short circuit or disconnection of the circuit. For this reason, a method of attaching a pellicle to one side or both sides of the mask has been adopted to prevent foreign substances on the surface of the mask.

A pellicle has an outer shape as shown in a front view and a side view of FIG.
A few nanometers of nitrocellulose or fluororesin
A pellicle film 2 having a thickness of several μm is adhered with an adhesive 3, and the pellicle film 2 is fixed so as to cover a pattern on a mask.

However, in a pellicle using such an organic film or the like, as the wavelength used for improving the exposure accuracy is shortened, the transmittance is limited, and the exposure using an F ₂ laser (wavelength: 157 nm) is performed. Did not have sufficient transmittance. Further, although the transmittance itself has been improved by changing the composition of the organic film or adding additives, the optical energy of the ArF excimer laser or the F ₂ laser is very strong, and the decomposition of organic components and the like may occur. In some cases, the film may not have sufficient durability with respect to the number of shots at the energy used in actual exposure, that is, the use time.

On the other hand, synthetic quartz glass is known as a material that transmits the i-line and the g-line.
No. 7, it is proposed that a synthetic quartz glass plate is bonded to a pellicle frame as a pellicle plate and used as a pellicle. Here, the thickness of the pellicle plate is 0.01 to
It is said that it is desirable to be 0.5 mm, but in actual exposure, if there is a variation in the thickness of the pellicle plate, the optical path of refracted light changes, so the transfer pattern position shifts and good lithography can be performed. Absent. FIG. 2 conceptually shows this state, and shows a pellicle plate 4 having an inclined surface.
Is refracted in the direction of the arrow. For this reason, the thickness variation allowed for the pellicle plate is ± 0.
It is considered to be within 3 μm / 150 mm.

On the other hand, a synthetic quartz glass plate is sliced from a formed synthetic quartz glass block and processed into a plate.
ぺ Since the cleicle plate is required to have no scratches on the surface that hinders exposure, in order to use the synthetic quartz glass plate as a pellicle plate, the synthetic quartz glass plate after slicing is polished to a predetermined thickness. It is necessary to process it. This polishing is generally performed using a double-side polishing apparatus.

[0007] The processing of the pellicle plate includes a lapping process for rough cutting and a polishing process for mirror polishing, and a double-side polishing apparatus is used in each process. As a double-side polishing apparatus, a polishing apparatus as shown in a partial side view of FIG. 3 and a partial perspective view of FIG. 4 is known. This polishing apparatus comprises a lower surface plate 6 and an upper surface plate 7, and is used for polishing by applying a polishing cloth on the surface itself of cast iron or the like in a lapping process and in a polishing process.

The carrier 8 as a work holder has a gear formed on the outer periphery. By setting the carrier 8 between the sun gear 9 and the internal gear 10 in the apparatus main body and rotating the upper and lower platens or one of the platens, the carrier 8 rotates and both surfaces of the work 11 can be polished simultaneously. . Although not shown, the upper platen has an abrasive supply hole so that the abrasive can be supplied to the work 11 during polishing.

However, when processing with such an apparatus,
Because it is difficult to equalize the amount of polishing per unit time between the outer peripheral part and the central part of the work, and it is difficult to supply the abrasive so that it works evenly in the surface of the work, It was difficult to polish the surface uniformly within the surface, particularly, to process the plate thickness variation within ± 0.3 μm / 150 mm.

[0010]

SUMMARY OF THE INVENTION In view of the above situation, the present invention is directed to a short-wavelength light below an ArF excimer laser.
A synthetic quartz glass material is used as a material having a sufficient light transmittance and a sufficient energy resistance, and an in-plane plate thickness variation of ± 0. An object of the present invention is to provide a pellicle having a pellicle plate suppressed to within 3 μm / 150 mm and a method for manufacturing the pellicle.

[0011]

The inventors of the present invention have conducted tests using a double-side polishing apparatus conventionally used in the production of a pellicle plate. As a result, the plate thickness tends to be small at the outer peripheral portion and large at the central portion. And, it was found that the location where the displacement was large was in a limited range of the outer periphery, that is, the occurrence of sagging in which only the outer periphery of the polished pellicle plate became thin increased the thickness variation of the substrate. . In addition, since this tendency becomes smaller toward the inside of the carrier, it has been found that there is a difference in the polishing rate between the outer peripheral portion and the central portion of the carrier. The present invention has been made based on these findings.

That is, the present invention relates to a method for manufacturing a pellicle having a pellicle frame and a pellicle plate made of synthetic quartz glass adhered to the upper surface of the pellicle frame, wherein the pellicle has a size larger than the pellicle frame by at least 10 mm. Polishing a quartz glass plate, and then cutting the synthetic quartz glass plate to a predetermined size, a method for manufacturing a pellicle, comprising a step of manufacturing a pellicle plate,
And a method of manufacturing a pellicle comprising a pellicle frame and a pellicle plate made of synthetic quartz glass adhered to an upper surface of the pellicle frame, wherein the synthetic quartz glass is provided with a dummy processing portion attached to an outer peripheral portion of the synthetic quartz glass plate. A method for manufacturing a pellicle, comprising a step of manufacturing a pellicle plate by polishing the plate.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, as shown in FIG.
A substrate having a size larger by 0 mm (hereinafter, referred to as a base plate 13) is polished to a predetermined thickness, and then the outer peripheral portion is cut. As a result, a pellicle plate having good plate thickness variation can be obtained. Instead of this margin, a dummy processing portion 15 having the same thickness as the ぺ icle plate to be processed is provided on the outer periphery of the ク ル icle plate 14 as shown in FIG. , The outer peripheral sag is reduced.

At this time, the width of the dummy processing portion 15 is 10 m.
m or more. Further, since the polishing speed is equal to that of the pellicle plate to be processed, and the fine powder generated by polishing can prevent the pearlicle plate from being damaged during the processing, the dummy processing portion 15 may be made of synthetic quartz glass. It is preferable that the resin satisfy the same properties.

When the raw plate is polished, the polishing apparatus preferably has a size that can accommodate at least 131 raw plates within the radius of the carrier, or a size that can hold the entire dummy processing portion 15 within the radius. . This is to minimize the effect of the difference in polishing rate between the center and the outer periphery of the carrier.

Further, as shown in FIG. 7, if the shape of the base plate 17 is circular, the base plate is not fixed in the carrier, so that the base plate 17 moves freely in the hole of the carrier during polishing. In addition, the difference in polishing rate between the outer peripheral portion and the inner peripheral portion of the carrier can be reduced. Further, by attaching a circular auxiliary carrier 18 capable of holding a rectangular raw plate 14 to the carrier 16 which is an original work holder, as shown in FIG. The same effect as polishing the plate 17 can be obtained.

According to this method, the cut portion of the outer peripheral portion of the raw plate can be reduced or made unnecessary, so that the loss of material can be minimized. The circular auxiliary carrier 18 can have the same function as the dummy processed portion 15 by selecting the same thickness and material as those of the dummy processed portion 15 described above.

Next, a specific example of the present invention will be described. After cutting an ingot of a synthetic quartz material having a target thickness synthesized by a known method and transmitting 85% or more of light of a predetermined wavelength into a thickness of 152 mm × 152 mm × 2.3 mm by an inner peripheral slicer, a commercially available NC is used. Dimensions are 122mm x 14 with chamfering machine
Chamfering was performed so that the end face was 9 mm and had an R shape.

Next, this synthetic quartz glass plate was immersed in a 5% by mass HF solution in order to stop the progress of cracks caused by cutting and chamfering. Next, this synthetic quartz glass plate was used using a 16 F double-sided lapping machine made by Speed Fam, and a slurry in which FO # 1200 (trade name, manufactured by Fujimi Corporation) was suspended in filtered water by 10 to 12% by mass as an abrasive. And lapping was performed until the thickness became 0.35 mm.

Further, the synthetic quartz glass plate after the lap processing was subjected to the same etching treatment as described above. Subsequently, this synthetic quartz glass plate was used for 16F manufactured by Speedfam.
Polishing with a slurry mainly composed of cerium oxide and a polyurethane pad using a double-side polish machine, and then finishing polishing with a slurry mainly composed of cerium oxide and a foamed polyurethane pad using the same type machine, and a 305-μm-thick pellicle plate. I got

A thickness measuring device (laser focus displacement meter manufactured by KEYENCE CORPORATION) using a laser beam on the pellicle plate.
FIG. 9 shows the results of the measurement. As is clear from FIG. 9, although the outer peripheral portion of the plate is thin, the thickness variation of the portion except for 5 mm from the outer peripheral portion is good (Example 1). On the basis of this result, a blank having dimensions of 132 mm × 159 mm was previously processed in the above-described process, and the peripheral portion was cut to obtain 12 mm.
When a pellicle plate of 2 mm × 149 mm was obtained, 122
± 0.3 mm in thickness variation within the range of mm × 149 mm
It could be suppressed to within μm / 150 mm (Example 2). In addition, it is not limited to the apparatus, the abrasive, and the polishing cloth used in the above example, and any type can be used as long as the same performance and purpose can be achieved.

[0022]

According to the present invention, it is possible to obtain a pellicle provided with a synthetic quartz glass pellicle plate having an accuracy within ± 0.3 μm / 150 mm in thickness required as a pellicle plate.

[Brief description of the drawings]

FIG. 1 is a front view and a side view showing a pellicle.

FIG. 2 is a conceptual diagram of a deviation of an exposure light beam due to a thickness variation.

FIG. 3 is a partial side view of the double-side polishing apparatus.

FIG. 4 is a partial perspective view of a double-side polishing apparatus.

FIG. 5 is a conceptual diagram showing a pellicle plate of the present invention.

FIG. 6 is a conceptual diagram showing a relationship between a pellicle plate and a dummy processed portion in the present invention.

FIG. 7 is a conceptual diagram showing a relationship between a pellicle plate and a circular plate in the present invention.

FIG. 8 is a conceptual diagram illustrating a relationship between an auxiliary carrier and a carrier according to the present invention.

FIG. 9 is a graph showing a measurement result of a thickness variation in an example of the present invention.

[Explanation of symbols]

 1: frame 2: 膜 recurring film 3: adhesive 4: ぺ recurring plate 5: exposure light beam 6: lower surface plate 7: upper surface plate 8: carrier 9: sun gear 10: internal gear 11: work 12: external dimensions 13: Base plate 14: @Ricle plate 15: Dummy processing part 16: Carrier 17: Base plate 18: Auxiliary carrier

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhiro Matsumoto 1-1-1 Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 2H095 BC33 BC34 5F046 AA25 CB17 DA06

Claims (3)

[Claims] 1. A method of manufacturing a pellicle comprising a pellicle frame and a pellicle plate made of synthetic quartz glass adhered to an upper surface of the pellicle frame, wherein a synthetic quartz glass plate having an outer dimension larger than the pellicle frame by 10 mm or more is provided. A method for manufacturing a pellicle, comprising a step of manufacturing a pellicle plate by polishing and then cutting the synthetic quartz glass plate to a predetermined size. 2. A method for manufacturing a pellicle comprising a pellicle frame and a pellicle plate made of synthetic quartz glass adhered to an upper surface of the pellicle frame, wherein a dummy processing portion is mounted on an outer peripheral portion of the synthetic quartz glass plate. A method for manufacturing a pellicle, comprising a step of manufacturing a pellicle plate by polishing a synthetic quartz glass plate. 3. A pellicle obtained by the method for producing a pellicle according to claim 1.