JPS6159449A - Mask for producing semiconductor - Google Patents

Abstract

PURPOSE:To prevent the electrostatic charge of an insulator substrate and to test exactly a micropattern by providing a light transmittable and charge conductive film covering the pattern of a metallic material on the insulating substrate and grounding the conductive film. CONSTITUTION:The pattern 12 of chromium or chromium oxide is formed on an insulator, for example, a glass substrate 11 and the pattern 12 is coated with the conductive film 13. The film 13 is grounded to the earth 15 by an electric wire 14. The charge generated in the surfaces of the substrate 11 and the film 13 is grounded and therefore the secondary electrons radiated from the pattern 12, the substrate 12 and the film 13 have consequently the peak value conforming to the design value. The analysis of the secondary electrons by a secondary electron detector indicates exactly the shape of the chromium pattern 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mask for semiconductor manufacturing, and particularly to a mask for wafer exposure or a reticle serving as a mask original plate.

[Conventional technology]

In the manufacturing of semiconductor devices, it is common to apply photoresist to a wafer to form a photoresist film, expose the resist film on the wafer to light through a photomask, develop the resist film, and then perform various treatments on the wafer. It will be done. The photomask used for exposing such wafers includes
There are 1,000 patterns on the glass substrate that do not allow light to pass through.
It is made of a metal, for example chromium, with a film thickness of ~2,000 mm.

The pattern width of the photomask described above has been reduced to 1.5 to 2.0 μm in order to meet the demand for miniaturization of integrated circuits, but recently the pattern width has been reduced to the order of submicrons. is required to do so.

The above-mentioned photomask patterns are always inspected, and conventionally this inspection has been carried out using an optical system, in which light is applied and converted into a video signal through a lens. By the way, when the pattern width becomes submicron, the limit of resolution in inspection using light is 1.0 μm, so it is no longer possible to inspect submicron patterns using conventional optical systems.

Therefore, a method using an electron beam (EB) instead of light was developed. Pattern inspection using EB employs a method of detecting secondary electrons generated by EH irradiation.

[Problem that the invention seeks to solve]

FIG. 2 schematically shows a photomask in cross-section, and in the same figure, 1 is a glass substrate, 2 is a chrome pattern, and 3
indicates EB, and 4 indicates secondary electrons emitted from pattern 2. As shown in the figure, the mask is scanned at <EB3, and the emitted secondary electrons 4 are detected by the secondary electron detector 5.

In inspecting a pattern using such an IEB, it was found that if EB irradiation is continued, the glass substrate is an insulator, so charges are accumulated therein (charge up) and the glass substrate becomes electrically charged. In this case, the electric charge affects the secondary electrons, and the peaks of the secondary electrons emitted from the chromium and glass substrates overlap, making it impossible to accurately detect the secondary electrons and making it impossible to accurately inspect the pattern. A problem occurred that disappeared.

[Means for solving problems]

The present invention provides a photomask in which the insulator substrate is prevented from being charged, which solves the above-mentioned problems, and its means include:
The mask has a metal material pattern provided on an insulating substrate, a light-transmitting charge conductive film covering the pattern is provided on the insulating substrate, and the conductive film can be grounded. This is achieved by a semiconductor manufacturing mask characterized by the following.

[Effect]

In the above mask, the charges accumulated on the surface of the glass substrate are grounded through the conductive film, so the secondary electrons irradiated from the chrome pattern are not affected in any way. Since the peak values of the secondary electrons from the glass substrate and the conductive film are accurate, the pattern can be accurately inspected by detecting the secondary electrons.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

An embodiment of the present invention is shown in a partial cross-sectional view in FIG. 1, in which reference numeral 11 denotes a substrate of an insulator such as glass, and 12 a film made of chromium or chromium oxide with a thickness of 1,000 to 2,000 mm.
000 pattern, 13 is a conductive film, and 14 is an electric wire that grounds the conductive film to the ground 15. Since it is impractical to connect an electric wire to each mask that is actually used, the conductive film may be provided with grounding means using conventional techniques.

The conductive film is made by applying a light-transmitting material that conducts charge to a thickness two to three times that of the pattern by, for example, a spin-coating method. By providing such a conductive film,
Since the charges generated on the surfaces of the glass substrate 11 and the conductive film 13 are grounded, the secondary electrons emitted from the pattern 12, the glass substrate 11, and the conductive film 13 have a designed peak value. Therefore, analysis of these secondary electrons by a secondary electron detector will accurately indicate the shape of the chrome pattern 12. In the inspection of the pattern 12, the secondary electrons from the edges of the pattern have an important meaning, and conventionally, the secondary electrons emitted from the edges (including the secondary electrons from chromium and the glass substrate) However, according to the embodiment of the present invention, it has become possible to accurately analyze the peak value of each secondary electron.

As described above, the conductive film must not only conduct charge but also have light transmittance and be able to be coated on a glass substrate.

In the first example of the present invention, a complex molecular composition, such as a carphone blank dispersed in polymer 7 trisox, was used as the conductive membrane and good analysis was performed.

In a second embodiment of the present invention, polymer charge transfer ijf
for example, polyvinyl Rubadur, which is a donor for polymeric polycations, and tetracyano-P-quinodimethane (T
Using the combination with CN Q), the same effect as in the first example was obtained.

In the third embodiment of the present invention, an ion-conductive polymer, such as β-alumina ceramics, is used for the conductive film, and in the fourth embodiment, a conductive interlayer compound conductor, such as graphite, is used. Using -5-NuZSbC Roasted 5, satisfactory results were obtained in all cases.

In the fifth embodiment of the present invention, conductive conjugated composites are used, including: 1.
(trans platinum acetylide), ■ polyarylene vinylene, ■ poly(chlorophenylquinoline), ■ polyaminopyridine, and ■ selenium-containing aromatic acid polymer.

The conductive film j3 not only has the function of dissipating charges from the glass substrate as described above, but also has the advantage of serving as a protective film for protecting the pattern 12.

〔Effect of the invention〕

As explained above, according to the present invention, by providing a conductive film, the influence of electric charge generated on an insulating substrate can be prevented in inspecting a fine pattern of a photomask using EB. In addition to ensuring accurate testing, the conductive film also protects the pattern.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of a photomask according to the present invention;
FIG. 2 is a partial cross-sectional view of a conventional photomask. In the figure, 11 is a glass substrate, 12 is a pattern, 13 is a conductive film, 14 is an electric wire, and 15 is a ground. Figure 1

Claims (6)

[Claims] (1) A mask comprising a metal material pattern provided on an insulating substrate, a light-transmitting charge conductive film covering the pattern provided on the insulating substrate, and the conductive film being grounded. A mask for semiconductor manufacturing, characterized by having a wet structure. (2) The mask for semiconductor manufacturing according to claim 1, wherein the conductive film is a composite polymer composition such as one in which carbon black is dispersed in a polymer matrix. (3) A mask for semiconductor manufacturing according to claim 1, wherein the conductive film is a polymeric charge transfer complex such as a combination of polyvinylcarbazole, which is a donor of a polymeric polycation, and tetracyano-p-quinodimethane. . (4) The mask for semiconductor manufacturing according to claim 1, wherein the conductive film is an ion conductive polymer such as β-alumina ceramics. (5) The conductive film is graphite-S_4N_4ZSbCl_
5. The mask for semiconductor manufacturing according to claim 1, which is an interlayer compound conductor such as No. 5. (6) The conductive film is made of a conductive material such as polyparaphenylene, polyphenylene sulfide, polythiazyl, polythienylene, poly(trans platinum acetylide), polyarylene vinylene, poly(chlorophenylquinoline), polyaminopyridine, or a selenium-containing aromatic polymer. The mask for semiconductor manufacturing according to claim 1, which is a conductive conjugated polymer.