JPS6326821Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a pellicle dustproof film for a reticle of a photolithography apparatus (exposure apparatus) used in the manufacture of semiconductor devices.

Conventional technology Photolithography is used in the manufacture of semiconductor devices (IC, LSI, etc.), especially when exposing a resist. If foreign matter such as dust adheres to the reticle, which is a photomask, it is transferred to the resist pattern, so the reticle is kept clean. There is a need. For this purpose, reticle cleaning is performed (for example, Kazunori Imamura: Reticle cleaning machine NRW-503, Electronic Materials, March 1984 issue,
(Refer to Vol. 23, No. 3, [Kogyo Kenkyukai], pp. 94-97).
Additionally, the use of pellicle dustproof membranes has been adopted which can greatly reduce or eliminate this reticle cleaning task. This pellicle film prevents dust from directly adhering to the reticle, and since it maintains a distance of several mm from the reticle, dust adhering to the pellicle film is not transferred (for example, Sato et al.
Canon FPA1500 reduction projection exposure system, electronic materials,
(See Figures 4 and 5 in the March 1984 issue of Kogyo Kenkyukai, pp. 26-31).

Problems that the invention aims to solve If the pellicle film is set at a position 4 mm away from the pattern surface of the reticle, dust particles smaller than about 70 μm will not be transferred. If dust larger than this size adheres to the pellicle film and cannot be removed, it will be transferred to the resist pattern, so the pellicle dustproof film must be removed and replaced with a new one. Since adhesive is used to attach the fixing frame of the pellicle dust-proof membrane to the reticle, this replacement work requires the use of chemicals to destroy it, which is very time-consuming.

Means for Solving the Problems According to the present invention, in order to replace the pellicle film with a new one without removing the fixing frame of the pellicle dust-proof film from the reticle when large dust that is transferred to the pellicle film adheres to the pellicle film. To provide a pellicle dustproof film in which a plurality of metal frames to which pellicle films are pasted are prepared and these are removably stacked on a fixed frame.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail by way of preferred embodiments of the present invention in conjunction with the accompanying drawings.

FIG. 1 is a cross-sectional view of the pellicle dustproof film according to the present invention attached to both sides of a reticle, and FIG. 2 is an enlarged cross-sectional view of portion A in FIG. 1.

The pellicle dustproof membrane of the present invention is obtained by sequentially stacking metal frames 2 and 3 to which pellicle membranes are attached on top of a conventional fixed frame 1 with pellicle membranes. Pellicle membranes 4, 5, and 6 are attached to frames 1, 2, and 3, respectively. Pellicle membrane is an ultra-thin nitrocellulose film (e.g.
2.85μm), and the frame is made of metal such as aluminum. The height of the fixed frame 1 is preferably about 3 to 6 mm, and the height of the metal frames 2 and 3 is preferably about 1 to 2 mm.

A plurality of metal frames 2 and 3 to which the pellicle film is attached are prepared, and before being attached to the reticle 7, these are mounted on the fixed frame 1 and fastened to the fixed frame by a gripping tool (not shown). As the gripping tool, one using an elastic body or one using a screw action can be used. The pellicle dust-proof film according to the present invention, which includes a plurality of pellicle films (three in the drawing), is attached to the front and back surfaces of a reticle using an adhesive in the conventional manner as shown in FIG. If large particles adhere to the surface of the pellicle film 6 during work with the exposure equipment and cannot be removed using _N2 purge, etc., the pellicle film 6 can be removed by removing only the metal frame 3 from the gripper. Then, the new pellicle membrane 5 is used as a dustproof membrane. Next, only the metal frame 2 is removed from the gripper, and finally, when the third pellicle film 4 is contaminated with dust, the fixed frame 1 is removed from the reticle 7.

The number of stacked pellicle films is preferably five or less, taking into consideration the transmittance, absorption and scattering of the films themselves.

Effects of the Invention With the pellicle dustproof film according to the present invention, the dustproof action time of the pellicle film without being removed from the reticle is increased several times by the number of stacked metal frames to which the pellicle film is attached.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a pellicle dustproof film and a reticle according to the present invention, and FIG.
It is an enlarged sectional view of a part. 1... fixed frame, 2, 3... metal frame, 4, 5, 6... pellicle membrane, 7... reticle.

Claims (1)

[Scope of utility model registration request] A pellicle dust-proof membrane consisting of a metal fixed frame and a pellicle membrane attached to the pellicle, characterized in that a plurality of metal frames to which pellicle membranes are attached are removably stacked on the metal fixed frame. Dustproof membrane.