JP3429869B2 - Pellicle manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a pellicle, and more particularly, a method for manufacturing a pellicle for lithography used as a dust shield for a mask for lithography when manufacturing a semiconductor device such as an LSI or VLSI or a liquid crystal display panel. It is about the method.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices such as LSI and VLSI, or liquid crystal display plates, etc., a semiconductor wafer or liquid crystal display plate is irradiated with light to form a pattern. If dust adheres to the lithography mask), the dust absorbs light or bends the light, resulting in deformed transferred pattern, sharp edges, and black background. However, there is a problem in that the dimensions, quality, appearance, etc. are impaired. For this reason, these operations are usually performed in a clean room, but it is difficult to always keep the exposure master clean in this clean room.Therefore, the exposure master light often passes through the surface of the exposure master for exposure to prevent dust. A method of attaching a pellicle to be used is performed.

In this case, since the dust does not directly adhere to the surface of the exposure original plate but adheres to the pellicle film, if the focus is set on the pattern of the exposure original plate during lithography, the dust on the pellicle film will be transferred. Becomes irrelevant to. The basic structure of the pellicle is to apply a good solvent for the pellicle film onto a pellicle frame made of aluminum, stainless steel, polyethylene, etc., which is a transparent film made of nitrocellulose, cellulose acetate, etc., that allows the light used for exposure to pass well, and then air-dry. (See JP-A-58-219023) or an adhesive such as an acrylic resin or an epoxy resin (see U.S. Pat. No. 4,861,402, JP-B-63-27707), and a pellicle. An adhesive layer made of polybutene resin, polyvinyl acetate resin, acrylic resin or the like for fixing the exposure master plate, and a release layer (separator) for the purpose of protecting the adhesive layer are formed below the frame.

In the manufacture of this pellicle, a pellicle film having the same size as that of the pellicle film is not usually attached to the frame holding the pellicle film, but a film slightly larger than the pellicle frame is produced and bonded to the pellicle frame. After that, the unnecessary film protruding to the outside of the pellicle frame is cut and removed. This unnecessary film cutting / removing method includes a mechanical method of cutting and removing with a cutter, a thermal method of cutting and removing with a heater or a laser, and a dissolving method of cutting and removing the soluble solvent by dissolving it in the pellicle film. Can be considered.

[0005]

However, the method of dissolving and removing the film with the solvent as one of the methods for removing the unnecessary film is substantially free from dust generation and has a good cut surface shape. Although an excellent method, which includes cutting the solvent was added dropwise along the pellicle adhesive surface peripheral portion of the pellicle frame, the dropped liquid proceeds spontaneously along the chamfered portion of the frame end portion, to dissolve the film To be a method
It is difficult to control the solvent used at the time of cutting, such as controlling the dropping amount, dropping position, and route of the liquid after dropping, which is unexpected on the pellicle film or frame in the process of removing unnecessary film cutting. The solvent that has been cut off progresses to dissolve the pellicle film, generate stains and stains, and also leave foreign matter, and cause stains and stains on the pellicle frame, causing a significant decrease in product yield. There is.

[0006]

The present invention relates to a method for producing a pellicle that solves the above disadvantages and problems, and it is a solvent capable of dissolving a pellicle film in the step of removing an unnecessary film in pellicle production. The drops on the cutter
It is characterized in that the unnecessary film is removed by using a cutter and the solvent at the same time. The boiling point of the solvent
The point is preferably 80 ° C. or higher and 180 ° C. or lower.

That is, as a result of various investigations by the present inventors to develop a method capable of efficiently and easily removing an unnecessary film at the time of manufacturing a pellicle, as a result, an unnecessary film is removed from the manufactured pellicle. Move the cutter along the outer periphery of the pellicle adhesion part on the pellicle frame, drop a solvent that can dissolve the pellicle film on this cutter, and cut the unnecessary part of the pellicle film with the cutter and solvent to remove the solvent. The present invention has been completed by finding that unnecessary films can be cut and removed with good reproducibility without supplying stains on the pellicle film and the pellicle frame with good controllability. This will be described in more detail below.

[0008]

The present invention relates to a method for manufacturing a pellicle, and more particularly to a method for cutting and removing an unnecessary portion of a pellicle film in a pellicle manufacturing process. It is characterized by performing simultaneously using a cutter and a solvent capable of dissolving the pellicle film, for example, by moving the cutter inserted in the pellicle film along the outer periphery of the pellicle film adhesion part on the pellicle frame, When a solvent capable of dissolving the pellicle film is dropped onto the cutter, the cutter and the solvent provide an advantage that the unnecessary film is efficiently cut and removed without causing stains or the like.

In the present invention, the type of the pellicle film to be cut and removed is not particularly limited, and examples thereof include conventionally used nitrocellulose, cellulose acetate, cellulose propionate, amorphous fluoropolymer and the like. Further, the shape, size (thickness), material, etc. of the cutter used here are not particularly limited, and since the shape is such that it can be easily inserted into the pellicle film, for example, the tip has an acute angle and the solvent It is desirable to use a material that does not dissolve or deteriorate due to. The conditions for inserting this blade into the membrane are 90 ° when viewed from the inside of the frame.
There is no particular limitation as long as it is greater than 180 degrees and less than 180 degrees, but the angle of the thread surface (45 degrees) that is usually provided at the end of the frame
It is preferable to make the same as the above, and an example of installation of this blade portion may be as shown in FIG. 1, for example.

Next, the solvent used here is not particularly limited as long as it dissolves the pellicle membrane to be cut and removed. For example, nitrocellulose, ethyl cellulose, cellulose propionate, acetyl cellulose or the like is used as the pellicle membrane. In this case, a solvent such as butyl acetate, ethyl lactate, methyl isobutyl ketone or ethyl cellosolve acetate can be used. When the pellicle film is made of an amorphous fluoropolymer such as Teflon AF (trade name manufactured by DuPont, USA) and Cytop [trade name manufactured by Asahi Glass Co., Ltd.], Fluorinert (trade name manufactured by 3M Co., Ltd.) ), CT Solve [Asahi Glass Co., Ltd.
Fluorine-based solvent such as product name] can be used.

The boiling point of this solvent is not particularly limited, but if it is lower than 80 ° C., the evaporation rate at room temperature is fast and it becomes difficult to control the dropping amount, and if it is higher than 180 ° C. The evaporation rate slows down significantly, which not only causes stains on the frame and pellicle film, but also gradually dissolves the pellicle film at the adhesion part to cause adhesion failure and the solvent remains without evaporating. It is preferably 80 ° C or higher and 180 ° C or lower.

As a method of moving the cutter inserted in the pellicle film along the outer periphery of the pellicle film bonding portion on the pellicle frame, there are a method of manually moving the cutter and a method of mechanically moving the cutter. In order to prevent foreign matter from adhering to the pellicle film when removing the unnecessary film, it is preferable to move it mechanically. As a method of mechanically moving the cutter, a cutting target is placed on an XYZθ stage and fixed by a cutter, a cutter is attached to the tip of a scalar robot to cut, and a tip of a SAM (6-axis manipulator) is attached. There is a method of attaching a cutter and cutting. The method of dropping the solvent on the cutter is not particularly limited, and any method such as air type microdispenser or tube type microdispenser, natural dropping, manual dropping using a microsyringe can be performed. A mechanical dropping method is preferable from the viewpoint of controllability of the dropping liquid amount.

[0013]

EXAMPLES Next, examples and comparative examples of the present invention will be described. Example 1 Teflon AF1600 (trade name, manufactured by DuPont, USA) was dissolved in a fluorine solvent, Fluorinert FC-75 (trade name, manufactured by 3M, USA) to prepare a solution having a concentration of 8%. This solution had a diameter of 200 mm and a thickness of 200 mm. The surface of a 600 μm mirror-polished silicon substrate is coated using a spin coater and the film thickness is
After forming a 0.8 μm transparent film, the outer dimension 2
A frame with a width of 00 mm × 200 mm × 5 mm and a thickness of 5 mm is bonded using an epoxy adhesive Araldite Rapid [trade name of Showa High Polymer Co., Ltd.] and then peeled in water to form a pellicle film. did.

Next, an aluminum alloy frame having an outer frame size of 100 mm × 100 mm × 5 mm and a frame thickness of 4 mm is bonded to the film surface of the formed Teflon AF1600 using an epoxy adhesive Aralday Rapid (described above). Then
These two frames are attached to a fixing jig with the adhesive surface of the pellicle frame facing upwards and fixed so that their relative positions do not shift, and this also has a thickness of 0.25 mm for film cutting.
The stainless steel cutter of was attached to the scalar robot.

Next, using a tube type dispenser for this cutter, while dropping 10 microliters of the above-mentioned fluorine-based solvent, Fluorinert FC-75, per minute along the peripheral portion of the adhesive portion of the pellicle frame, While moving, remove the unnecessary film part outside the pellicle frame, and remove the foreign matter on the pellicle film obtained by removing this unnecessary film part using a condensing lamp (400,000 lux) in the dark room. At the time of measurement, no foreign matter of 0.3 μm or more was observed, and 10
Observed with a stereoscopic microscope, no dripping of liquid or adhesion of foreign matter was observed, and the cut surface of the membrane was observed with a 100 × stereoscopic microscope, but no scratches or fraying was observed.

Comparative Example 1 Teflon AF1600 (described above) was dissolved in a fluorine-based solvent, Fluorinert FC-75 (described above) to prepare a solution having a concentration of 8%, and this solution was mirror-polished with a diameter of 200 mm and a thickness of 600 μm. After coating with a spin coater on the aforesaid silicon substrate to form a transparent film with a film thickness of 0.8 μm,
A frame having an outer size of 200 mm × 200 mm × 5 mm width and a thickness of 5 mm was adhered on this film using an epoxy adhesive Araldite Rapid (described above), and this was peeled in water to prepare a pellicle film.

Then, an aluminum alloy frame having a frame outer dimension of 100 mm × 100 mm × 5 mm and a frame thickness of 4 mm is adhered to the film surface of the formed Teflon AF1600 using an epoxy adhesive Aralday Rapid (described above). ,
These two frames are attached to a fixing jig with the adhesive surface of the pellicle frame facing upward, and fixed so that their relative positions do not shift.
A YZ automatic stage was prepared and the frame was fixed on the automatic stage together with the fixing jig.

Next, from the stage upper pellicle film, 0.3
Install the tube tip of the tube type dispenser at the position of mm, move the stage so that the tube tip of the tube type dispenser moves relatively along the frame, and use the above-mentioned fluorine-based solvent Fluorinert FC-75 (previously mentioned). While dropping 10 microliters per minute, by moving along the peripheral portion of the adhesive portion of the pellicle frame, the unnecessary film portion outside the pellicle frame is cut and removed, and the unnecessary film portion is removed. When foreign matter on the film was measured in a dark room using a concentrating lamp (400,000 lux), the number of foreign matter of 0.3 μm or more was not observed, and the cut surface was observed with a 100 × microscope. No scratches or blistering were observed, but when observing the side of the pellicle frame with a 10X stereomicroscope, it was found that the liquid drips. Adhesion of foreign matter seems residue of the dissolved film was observed.

Example 2 CYTOP CTX809SP2 [trade name of Asahi Glass Co., Ltd.] was dissolved in a fluorine solvent CT-SOLV. 180 [trade name of Asahi Glass Co., Ltd.] to prepare a solution having a concentration of 3%. 200m diameter of solution
m, 600 μm thick on a mirror-polished silicon substrate surface,
After coating with a spin coater to form a transparent film with a film thickness of 0.8 μm, the outer dimensions of this film are 200 mm x 200 m.
A pellicle film was prepared by adhering a frame having a width of 5 mm and a thickness of 5 mm using an epoxy adhesive Araldite Rapid (described above) and peeling the frame in water.

Then, this film-formed CYTOP CTX809S
An aluminum alloy frame with outer dimensions of 100 mm × 100 mm × 5 mm and a frame thickness of 4 mm is bonded to the P2 film surface using the epoxy adhesive Aralday Rapid (described above), and these two frames are the same as the pellicle frame. It was attached to a fixture for fixing with the adhesive surface facing upward and fixed so that the relative position did not shift, and a 0.25 mm thick stainless steel cutter was attached to the film cutting jig scalar robot. .

Next, using a tube type dispenser for this cutter, while dripping 10 microliters of a fluorine-based solvent, CT-SOLV100 [trade name of Asahi Glass Co., Ltd.] per minute, the adhesive portion of the pellicle frame was removed. While moving the cutter along the peripheral part, the unnecessary film portion outside the pellicle frame is cut and removed, and the foreign matter on the pellicle film obtained by removing this unnecessary film portion is collected by a concentrating lamp (400,000 lux). When measured in a dark room using
The number of foreign matter of more than m was not observed, and the side surface of the pellicle frame was observed with a stereoscopic microscope at 10 times. No liquid dripping or foreign matter was observed.
Observation with a stereoscopic microscope with a double magnification revealed no scratches or fraying.

Comparative Example 2 CYTOP CTX809SP2 (described above) was used as a fluorine-based solvent CT-SOLV.
A solution with a concentration of 3% was prepared by dissolving it in 180 (above), and this solution was applied onto a mirror-polished silicon substrate with a diameter of 200 mm and a thickness of 600 μm using a spin coater, and the film thickness was 0.8 μm. After forming the transparent film, a frame with an outer size of 200 mm × 200 mm × 5 mm and a thickness of 5 mm is adhered to this film using the epoxy adhesive Aralday Rapid (described above) and then peeled off in water. To produce a pellicle film.

Then, the outer dimensions of the frame are attached to the pellicle film 1
An aluminum alloy frame with a size of 00 mm × 100 mm × 5 mm and a frame thickness of 4 mm is adhered using an epoxy adhesive Aralday Rapid (described above), and these two frames are fixed with the adhesive surface of the pellicle frame facing up. It was attached to a jig and fixed so that the relative position did not shift. Further, an XYZ automatic stage was separately prepared as an instrument for film cutting, and the frame was fixed together with the fixing jig on the automatic stage.

Next, from the stage upper pellicle film, 0.3
Install the tube tip of the tube type dispenser at the position of mm, move the stage so that the tube tip of the tube type dispenser moves relatively along the frame, and drop 10 microliters of CT-SOLV100 (mentioned above) per minute. However, the unnecessary film portion outside the pellicle frame is cut and removed by moving along the peripheral portion of the adhesive portion of the pellicle frame, and the foreign matter on the pellicle film obtained by removing the unnecessary film portion is removed. When measured in a dark room using a concentrating lamp (400,000 lux), the number of foreign matter of 0.3 μm or more was not observed, and when observing the cut surface of the film with a microscope of 100 times, scratches and fraying were recognized. However, when observed on the side surface of the pellicle frame with a 10 × stereoscopic microscope, it was found that the liquid drips and the residue of the dissolved film remained. Adhesion of objects was recognized.

[0025]

According to the pellicle manufacturing method of the present invention ,
It is easy to control the solvent supplied when cutting the pellicle-free film.
As a result , not only can the pellicle unnecessary film be cut and removed without dust generation, but also a pellicle that is free from stains and stains on the pellicle film and pellicle frame that have been generated during conventional cutting can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an installation example of a blade portion for removing an unnecessary film according to the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-145292 (JP, A) JP-A-63-191619 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03F 1/14

Claims (2)

(57) [Claims] 1. A solvent capable of dissolving a pellicle film is dropped onto a cutter in a process of removing an unnecessary film in pellicle production.
And a method of manufacturing a pellicle, wherein the unnecessary film is removed by using a cutter and the solvent at the same time. 2. The boiling point of the solvent is 80 ° C. or higher and 180 ° C. or lower.
The method for producing a pellicle according to claim 1, which is below.