JPH03214160A - Photomask - Google Patents

Abstract

PURPOSE:To shorten the time required to produce a photomask and to reduce the cost of the photomask by coating an optically transparent substrate with a compd. causing fading reaction and color development reaction under light in a region from UV to IR so that a pattern can directly be written and vanished. CONSTITUTION:A pattern recording layer 1 is formed on a quartz sheet as a substrate 2 by spin coating with a spiropyrane compd. dispersed in polystyrene or direct vapor deposition of the spiropyrane compd. A drawn pattern 3 is written in the pattern recording layer 1 by a direct drawing method with He-Cd laser light. When the entire surface of the resulting photomask is irradiated with IR rays, the pattern 3 is vanished and the layer 1 is made transparent again. A pattern is written again in the layer 1 with He-Cd laser light. The time required to produce the photomask is shortened and the cost of the photomask is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photomask, and particularly to a photomask that allows direct pattern writing and erasing using light and infrared light.

[Conventional technology]

The conventional manufacturing method for this type of photomask is shown in Figure 3(a).
-(d) As shown in FIG. 3(a), a metal thin film 5 is first deposited on a quartz plate 2, and then a resist 4 is applied.

Next, as shown in FIG. 3(b), direct electron beam drawing is performed, the uncured portion is removed by development, and the pattern 4 of the resist is
A is formed and used as a mask for etching.

Next, as shown in FIG. 3(c), the thin metal M5 is removed by etching using the resist 4a as a mask to form a pattern 5a of the metal thin film.

Next, as shown in FIG. 3(d), a resist pattern 4
When a is peeled off and removed, a conventional photomask is completed.

[Problem to be solved by the invention]

The conventional photomask described above has the disadvantage of a long process, as it involves the steps of forming a metal thin film, applying a resist for etching processing, pattern drawing, developing the resist, and etching the metal thin film. This is disadvantageous for products such as products that require shortened construction times.

In addition, photomasks are generally expensive because they use quartz as a support material, and if it is necessary to modify the circuit, the cost of reproducing the photomask is also high, which is directly added to the manufacturing cost of semiconductor devices. Because of the bounce, an inexpensive photomask is desired.

The purpose of the present invention is to shorten the manufacturing period of a photomask,
Another object of the present invention is to provide a photomask that can be used repeatedly, reduce costs, and allow easy modification of the photomask.

[Means to solve the problem]

The photomask of the present invention is a photomask used in the production of semiconductor devices, in which an optically transparent support is coated with a compound that reacts with photobleaching and photocoloring in the ultraviolet to infrared region, and is directly patterned. The feature is that the data can be erased.

The photomask of the present invention does not require etching of a fine pattern made of a metal thin film, and the pattern can be obtained by direct writing with light, infrared rays, etc., so that the manufacturing period of the photomask can be shortened.

In addition, the photomask of the present invention uses light of a different wavelength from that for drawing.
Since the pattern can be erased with infrared rays or the like, it can be used repeatedly as much as possible, and manufacturing costs can be reduced.

Furthermore, since the photomask can be easily modified by selectively erasing and rewriting the pattern, if only a portion of the circuit is modified, it is possible to both shorten the construction period and reduce costs.

〔Example〕

Next, the present invention will be explained with reference to the drawings. FIGS. 1(a) to 1(d) are longitudinal sectional views for explaining one embodiment of the present invention. In FIG. 1(a), a pattern recording layer 1 is spin coated on a support 2, and the support 2 is not a quartz plate.

Further, the pattern recording layer 1 was prepared by dispersing a spiropyran compound in polystyrene and coating or directly depositing the spiropyran compound. In this example, a 1,3,3-trimethylindolinobenzopyrylspirane derivative was used.

Further, when the pattern recording layer 1 is formed by adding an additive such as benzophenone to the spiropyran compound, the quantum efficiency of the reaction increases, so writing can be performed at a higher speed, resulting in an improvement in throughput. All film thicknesses are 1 to prevent a decrease in resolution.
It was set to 0 μm or less.

In FIG. 1(b), a drawing pattern 3 is written on the pattern recording layer 1 by a direct drawing method using 325 nm light of a HeCd laser. The drawing pattern 3 becomes optically opaque to 436 nm light, which is the exposure wavelength currently widely used in reduction projection exposure apparatuses. The optical density of the drawn pattern 3 was adjusted by the molar concentration of the spiropyran compound to be dispersed and the thickness of the pattern recording layer 1. When the spiropyran compound was directly deposited, the optical density was adjusted depending on the film thickness.

In FIG. 1(c), the entire surface of the photomask was irradiated with infrared rays. As a result, the drawing pattern 3 is erased and becomes transparent to 436 nm again.

Moreover, in FIG. 1(d), after erasing the -degree drawn pattern 3, a pattern is written again using 325 nm light of a He--Cd laser. At this time, the pattern drawn in FIG. 1(b) can be corrected and written.

FIGS. 2(a) and 2(b) are longitudinal sectional views for explaining another embodiment of the present invention. FIG. 2(a) shows a pattern recording layer 1 coated by spin coating on a conventional photomask.

Further, in FIG. 2(b), a pattern is selectively written in the A part using a He-Cd laser in order to connect the B part and C part of the pattern created with the metal thin film 5. This embodiment has the advantage that the pattern drawn on a conventional photomask can be easily modified.

〔Effect of the invention〕

As described above, the present invention enables writing and erasing using light and infrared rays, thereby shortening the manufacturing period of a photomask, and reducing cost by repeatedly using the photomask.

Furthermore, by selectively erasing or writing part of the circuit pattern, the photomask can be easily modified.

[Brief explanation of drawings]

1(a) to 1(d) are vertical sectional views of a photomask for explaining one embodiment of the present invention and its operation, and FIG.
a) and (b) are longitudinal cross-sectional views of a photomask for explaining other embodiments of the present invention and their effects; FIG.
(d) is a vertical cross-sectional view for explaining a conventional photomask manufacturing method. DESCRIPTION OF SYMBOLS 1... Pattern recording layer, 2... Quartz plate, 3... Drawing pattern, 4... Resist, 5... Metal thin film, A
...Pattern correction section, B...Pattern made of a metal thin film, C...Pattern made of a metal thin film.

Claims (1)

[Claims] In photomasks used in the manufacture of semiconductor devices, an optically transparent support is coated with a compound that reacts with photobleaching and photocoloring in the ultraviolet to infrared region, making it possible to directly write and erase patterns. Features photomask.