JPS5850539A - Manufacture of photomask - Google Patents

Abstract

PURPOSE:To obtain a photomask free from pattern defects such as pinholes by implanting ions into a metallic thin film just under the deficient part of a resist and by dry etching the film not covered with the resist pattern. CONSTITUTION:Photosensitive resin 1 applied to a metallic thin film 2 on a glass substrate 3 is exposed to electron beams or light 4 and developed to form a desired resist pattern. In order to prevent the occurrence of defects such as pinholes, the film 2 under the deficient part 5 of the resist produced during the pattern formation is supplied with flows 6 of tungsten ions through the part 5 to implant tungsten ions. By suitably selecting the kind and quantity of ions to be implanted, in the next stage for etching the film 2 with gas plasma, the etching speed of the implanted part can be made remarkably higher than that of the unimplanted part of the film 2. Accordingly, the film 2 just under the part 5 is not removed in the etching stage, and the occurrence of pinholes is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of obtaining a photomask or reticle fM using a thin metal film such as chromium or a photosensitive material without pattern defects such as pinholes.

During the production of photomasks or reticles, pinholes or foreign matter in the photosensitive resin film, or dust adhering to the film, can cause defects or residue in the photosensitive metal thin film on the finished mask or reticle. Degrading the quality of the mask or rendering the reticle unusable.

Traditionally, residual defects in the shielding material of a mask or reticle are removed and corrected with a spot spotter or laser liberator. Defects caused by defects in the blocking material can be corrected by locally depositing metal on the defect. To repair such defects, it is necessary to repeat the same steps as the normal photomask or reticle manufacturing process, such as applying photosensitive resin, forming a mask pattern, and adhesion of the metal film, which results in a large loss of time. Without,
There is also the possibility that new defects may occur.

The present invention aims to reliably produce a photomask or reticle without pattern defects by adding a simple process of increasing etching resistance by implanting ions into the light-shielding metal thin film in the resist defect areas. It is.

Embodiments of the present invention will be described below with reference to the drawings. In the mask or reticle manufacturing process,
As shown in the figure, a photosensitive resin 3 coated on a metal thin film 2 (for example, chromium or chromium oxide film) on a glass substrate 1 is exposed to an electron beam or light 4, and then developed to obtain a desired shape. Form a resist pattern. In this resist pattern, if there is a pinhole-like defect 5 in this resist film, that portion will cause a pinhole defect to occur in the light-shielding metal film in a mask or reticle that is completed through a subsequent process. 1. In order to eliminate the occurrence of such pinhole defects, inject the underlying metal thin film 2 (e.g. chromium film or chromium oxide film) VC, tungsten into the resist defect 6 that occurs during resist butter/formation, and through the defect. An ion flow 6 is applied to implant the same ions (FIG. 3). In the next step of etching the metal thin film 2 using gas plasma, by appropriately selecting the type of ions to be implanted and the ion concentration, the etching rate of the implanted portion can be adjusted to that of the chromium oxide film to which no ungsten ions have been implanted. Etching speed using carbon tetrachloride gas plasma is 200 people/min.
The injected part cannot be etched.

Therefore, in the etching knee process, the resist defective portion 6
The metal thin film directly under the surface remains without being removed, and no pinholes are formed (FIG. 4). In other words, this method does not cause pinholes in the mask or reticle, which are not caused by defects in the resist film in the conventional method, and thus the photomask or reticle obtained by removing the resist film has a perfect pattern ( Figure 5). As described above, according to the method of the present invention, there is no need to perform the same mask or reticle manufacturing process again as in the conventional method, and there is no time loss.

Furthermore, there is no need to consider the occurrence of new defects.

[Brief explanation of drawings]

1 to 6 are diagrams for explaining the present invention in detail. 1... Photosensitive resin, 2... Metal thin film,
3...Glass substrate, 4...Electric f-beam, yt, vcx exposure, 5...Resist pattern defective part, 6...Ion implantation (ion flow)
.

Claims (1)

[Claims] A photoresist film is applied to L of the reflective metal thin film Vζ deposited on the transparent substrate, a desired resist butter/formation is performed on the photoresist film, and a predetermined ion implantation operation is performed from above the resist pattern. , the predetermined ion implantation is performed into the metal thin film directly under the resist defect through the defect in the resist pattern, and the metal thin film outside the resist pattern is then dry etched using gas plasma or the like. How to make a mask.