JPS602955A - Formation of photomask - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a photomask used in the manufacturing process of semiconductor devices such as ICs and LSIs.

Prior Art and Problems In the manufacture of ICs, LSIs, etc., photolithography technology is used to form elements. In that case, a photomask is used, and photolithography technology is used for manufacturing this photomask as well as for forming elements. The manufacturing process is to form a metallic chromium film on a glass substrate by spraying, apply photoresist on top of it, expose this photoresist using a reticle, develop it, and then apply a metallic chromium film. A photomask is created by selective etching.

In this photomask production process, etching of the metal PM film is unstable because the substrate is glass, and etching residue may be left behind. The drawback was that it could not be done.

OBJECTS OF THE INVENTION In view of the above-mentioned drawbacks of the conventional art, an object of the present invention is to provide a method for making a photomask, which allows monitoring the progress of etching during etching when a metal chromium film is etched in the photomask manufacturing process. That is.

According to the present invention, a pattern that becomes transparent after selectively etching the metal chromium film is provided in at least three places around the periphery of a photomask substrate having a metal chromium film formed on one side of a glass substrate. This is achieved by providing a method for making a photomask, characterized in that the pattern is monitored during etching to observe the progress of etching.

Examples of the invention Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

1 and 2 are diagrams for explaining the method of making a photomask according to the present invention; FIG. 1 is a perspective view of the photomask, and FIG. 2 is a diagram showing the etching state of the photomask by a dry etching device. .

In this embodiment, first, as shown in FIG. 1, a photoresist 2 is coated on a photomask substrate 1 having a metal chromium film formed on one side of a glass substrate, exposed using a reticle, and then developed.

In this case, the reticle includes the required area 3 of the photomask substrate 1.
At least three /f turns 4, 4', and 4'', which become transparent after etching, are formed in the peripheral area other than the photomask substrate. ', 4'' are formed by photoresist 2.

The photomask substrate l thus treated is inserted into a dry etching device 5 as shown in FIG. 2 and placed on a holder 6 with the metal chromium film facing upward.

Then, the inside of the device is evacuated through the exhaust hole 7, a mixed gas of carbon tetrachloride and oxygen is introduced, and a high voltage is applied between the holder 6 and the counter electrode 8 to generate zolar gas and chromium on the gold film. It etches the film. At this time, from the viewing window 9, the patterns 4, 4' and 4'' previously formed on the photomask substrate 1 are shown.
If you monitor everything, you can observe the progress of etching. Note that one way to monitor the patterns 4.4' and 4'' is to use a laser beam 10 to monitor the patterns 4, 4' and 4''.
．． 4", and the reflected light is received by a receiver,
The degree of progress of etching can also be determined by the change in output. Also pattern 4.4'.

The reason why 4 is formed at at least three locations is to widen the monitoring area and prevent etching residue.

In this way, in the non-example, the progress of etching of the metal chromium film can be observed, so the end point of etching can be easily found, and dust and etching residue can be prevented.

Although this embodiment has been described with reference to dry etching, the method of the present invention can also be applied to wet etching.

Effects of the Invention As explained in detail above, the method for making a photomask of the present invention involves forming, using a photoresist, a no'e turn that becomes transparent after etching on a photomask substrate having a metal chromium film formed on one side of a glass plate. By monitoring the pattern during etching, it is possible to find out when etching is complete.

[Brief explanation of the drawing]

1 and 2 are diagrams for explaining the method for producing a photomask according to the present invention. FIG. 1 is a perspective view of a photomask substrate, and FIG. 2 shows a photomask being etched by a dry etching device. It is a diagram. In the drawing, 1 is a photomask substrate, 2 is a photoresist), 4,4', 4'' is a turn that becomes transparent after etching, 5 is a dry etching device, 16 is a holder, 8 is a counter electrode, and 9 is a viewing window. , 10 indicate laser beams, respectively. Patent applicant Fujitsu Limited Patent agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney 1) Yukio Patent attorney Yamaguchi 118

Claims (1)

[Claims] 1. A pattern that becomes transparent after selectively etching the metallic chromium film is provided in at least three places around the periphery of a photomask substrate on which a gold-plated chromium film is formed on one side of the glass substrate, and the pattern is made transparent during etching. A photomask production method characterized by monitoring and observing the progress of etching.