JPH03181945A - Method for correcting pattern chipping defect of mask - Google Patents

Abstract

PURPOSE:To prevent the peeling of the film in a corrected part by washing by forming an intermediate layer which absorbs a laser beam over the entire surface of a mask prior to the execution of deposition by the laser beam and selectively removing this layer after a defect correction at the time of correcting the pattern chipping defect existing in the mask pattern. CONSTITUTION:An Al film is formed as the intermediate layer 6 by a sputtering method over the entire surface of the mask having the defect 3. The defect 3 part is then irradiated with the laser beam and a chromium film is formed as the deposition film 4 in the part irradiated with the laser beam by cracking the adsorbed gas. This mask is then immersed into phosphoric acid (H3PO4) and the Al film 6 as the intermediate layer is selectively removed, by which the defect correction is completed. Since the Al film 6 is formed over the entire surface as the intermediate layer on a substrate 1 at the time of forming the deposition film 4 for correction in such a manner, the laser beam is absorbed even on the glass substrate and, therefore, the deposition film having good adhesiveness is formed. The peeling of the film in the corrected part by the washing is obviated in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for correcting pattern defects on a photomask or an X-ray mask, which is the original of a circuit pattern of a semiconductor integrated circuit.

[Conventional technology]

In the manufacturing process of semiconductor integrated circuits, if there is a pattern defect on the photomask, which is the original plate of the circuit pattern, the common pattern defect will be transferred to all the transferred sheets, so the pattern defect on the photomask will be completely eliminated. Must be corrected.

A conventional method for correcting pattern defects such as pinholes and edge defects will be explained with reference to FIGS. 2 and 4. Fig. 2 is a schematic diagram of a mask with a pattern chipping defect, and Fig. 4 is a schematic diagram of a mask corrected by a conventional method.
b) shows a cross-sectional view taken along the line A-B in the same figure (a).

Referring to FIG. 2, the structure of the mask has a numerically-thickness of 0.
A mask pattern 2 made of a chrome casing or a metal film such as molybdenum silicide and having a thickness of about 100 OA is formed on the surface of a transparent mask substrate 10 made of 0.9 inch quartz glass or the like. However, 3 is an example of a pattern missing defect of mask pattern 2.

By the way, when repairing the pattern defect shown in FIG. 2, hexacarbonyl chromium (Cr(Co)s) '4? When the pattern defect 3 is irradiated with laser light such as a YAG laser while supplying an organometallic gas, the organometallic gas is decomposed and a metal film is deposited at the laser light irradiated area. The principle is that laser light is absorbed by the substrate and becomes thermal energy, which decomposes the organic metal gas adsorbed on the substrate surface.
It is called. In this way, a deposition film 4 is formed on the pattern defect 3 portion, as shown in FIG. 4, and the defect is corrected. At this time, if the deposition film 4 is made of metal, it can be put to practical use with a film thickness of about 1000 Å.

[Problem to be solved by the invention]

However, such conventional defect repair methods have the following problems. This will be explained with reference to FIG. If you wash the modified mask with high-pressure pure water or a scrubber,
As shown in FIG. 5, peeling 5 may occur as a defect in the deposition film 4 of the repaired portion. This is because when forming the deposition film 4, if the substrate 1 is made of a transparent material such as glass, the absorption of laser light is low, so it is difficult to deposit a metal film directly on the glass substrate. Defect 3
This is due to the fact that it grows from the mask pattern 2 around the . That is, the deposition film 4 for defect correction is adhered to the substrate at the portion above the mask pattern 2, but the adhesive force to the substrate (glass) at the defect 3 portion is weak, so that it easily peels off during cleaning. This is especially true when the defect size is 10
This becomes noticeable for large pinballs of μm2 or more and baton chipping defects at pattern edges.

As described above, the conventional method has a problem in that the repaired portion of the pattern chipping defect is easily peeled off by cleaning.

[Means to solve the problem]

In order to solve the problems of the prior art as described above, the present invention forms an intermediate layer that absorbs laser light on the entire surface of the mask before performing deposition by laser CVD, and selects the layer after correcting this defect. It was designed to remove them.

[Effect]

In the present invention, by providing an intermediate layer that absorbs laser light on the entire surface of the mask, the energy of the laser light is absorbed even on a single glass substrate, and a highly adhesive deposition film can be formed. This prevents the film from peeling off at the repair area.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3.

Fig. 1 is a process cross-sectional view showing an example of the mask defect repair method according to the present invention. Fig. 2 shows an example of a pattern missing defect, and Fig. 3 shows a defect repaired by the method of this embodiment. The latter mask is shown respectively. In these figures, the same or equivalent parts are indicated by the same reference numerals, and 6 is an intermediate layer such as a metal film formed before pattern correction.1 This intermediate layer 6 absorbs laser light. It is for the purpose of

Next, for convenience of explanation, the method of the above embodiment will be described using as an example the correction of a pattern missing defect shown in FIG. 2, as in the conventional example.

As shown in FIG. 1, an Al film with a thickness of 200'A is formed as an intermediate layer 6 by the spunter method on the entire surface of the mask having the trenches and defects 3 shown in FIG. 2 ((-'), (b) )')
.

Next, without supplying hexacarbonyl chromium (CR(CO)S) gas, a YAG laser beam is irradiated onto the defect 3, and by decomposing the adsorbed gas, a chromium deposition film 4 is formed on the laser beam irradiated area. A film is formed to a thickness of goon ((C) in the same figure).

Next, this mask is immersed in phosphoric acid (H3PO4) to selectively remove Al as the intermediate layer and the film 6, completing the defect correction as shown in FIG.
Figure (d)). At this time, since phosphoric acid does not etch the chromium film, the portion A1 covered with the chromium film 4
The film 6 remains without being etched.

As described above, according to the method of this embodiment, since the A1 film 6 is formed on the entire surface of the substrate as an intermediate layer when forming the correction deposition film 4, the laser light is absorbed even on the glass substrate. As a result, a deposition film with good adhesiveness is formed. Therefore, if pattern missing defects are corrected by the method of the present invention, the repaired areas will not peel off during cleaning.

In the above embodiment, AI is used as the intermediate layer 6, and wet etching with phosphoric acid is used for etching the intermediate layer 6. (1) It absorbs laser light.

■ Mask Hatan 4 can be used as a mask.

As long as these conditions are satisfied, other metals and other enchantments may be used, and a substance other than metals such as an organic film may be used as the intermediate layer. Alternatively, dry etching may be used instead of wet etching.

Furthermore, although the above embodiment uses a YAG laser for correction, other types of laser beams with other wavelengths may be used.

Furthermore, although the above embodiments have been described with respect to a photomask having a glass substrate, the same effect can be achieved with a b1 X-ray mask as long as the mask substrate is transparent.

〔Effect of the invention〕

As described above, according to the present invention, when repairing pattern missing defects existing in a mask pattern, an intermediate layer that absorbs laser light is formed on the entire mask surface before laser light deposition, and the defect is repaired. Later, this layer can be selectively removed.1 This intermediate layer absorbs the energy of the laser beam even on a transparent substrate such as glass, and a highly adhesive deposition film can be formed. This has the effect that the film in the repaired area will not peel off and a good mask without any defects can be obtained.

[Brief explanation of drawings]

Figures 1 (,) to (d) are process cross-sectional views showing one embodiment of the method of the present invention, and Figures 2 0 and (b) are schematic diagrams showing an example of a pattern chipping defect to explain the embodiment. 6) and (b) are a plan view and a cross-sectional view along the line A-B of the mark after correction by the method of the above embodiment, and FIG. (,) and (b) are a plan view of a mask showing an example of correction using the conventional method and its cross-sectional view taken along the line A-B. Figures 5 (,) and (b) are explanations of problems in the conventional method. FIG. 2 is a plan view and a cross-sectional view taken along the line A-B of a mask used for the purpose of the present invention. 1...Mask board, 2...Mask turn,
3...Pattern missing defect, 4.'...Deposition film for defect correction, 6...Intermediate layer.

Claims (1)

[Claims] In a semiconductor integrated circuit mask having a transparent substrate, when a pattern missing defect existing in the mask pattern is repaired, an intermediate layer that absorbs laser light is formed over the entire exposed surface of the mask pattern, and then the laser beam is CV
A method for repairing a pattern missing defect in a mask, which comprises correcting the pattern missing defect by deposition using D, and then using the deposition film as a mask to remove the intermediate layer other than the repaired portion.