JPH06282064A - Production of phase shift mask with auxiliary pattern - Google Patents

Abstract

PURPOSE:To provide the method capable of producing with high reliability the phase shift mask with an auxiliary pattern, the exposing light past which exhibits a steep light intensity distribution and which has high quality. CONSTITUTION:A chromium thin film (light shielding film) 2 uniformly formed on a transparent substrate 1 is subjected to a patterning treatment to form a main pattern 2a. The chromium thin film formed with the main pattern is irradiated with rays and the transmission pattern is inspected by an optical inspecting device. If there is a defect, the defect is repaired and thereafter, the chromium thin film is subjected to the patterning treatment again to form the auxiliary pattern 2b. In addition, a phase shift layer 4 is formed in the auxiliary pattern forming part of the chromium thin film. The auxiliary pattern is not formed in the chromium thin film (light shielding film) at the time of inspection according to this process for production and, therefore, the recognition of the auxiliary pattern as a defect does not arise even if the inspection level is set at a high level in the optical inspection device. The intrinsic defect is thus defected with high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-shielding film having a light-transmitting main pattern formed on a transparent substrate and a light-transmitting auxiliary pattern formed around the main pattern, and the above-mentioned auxiliary pattern formation of the light-shielding film. The present invention relates to a phase shift mask with an auxiliary pattern which is provided in a projection exposure apparatus and which is provided with a phase shift layer provided in a part thereof, and particularly relates to an improvement of a manufacturing method capable of reliably manufacturing a high quality phase shift mask with an auxiliary pattern. Is.

[0002]

2. Description of the Related Art A phase shift mask with an auxiliary pattern of this kind is used, for example, to form a non-repeatable isolated pattern such as a contact hole in a film formed on a semiconductor substrate when manufacturing a semiconductor device. It is what is used in the case.

As shown in the plan view of FIG. 2 and the sectional view of FIG. 3, this phase shift mask with an auxiliary pattern is provided with a transparent substrate a such as quartz glass and the isolated pattern provided on the transparent substrate a. And a translucent main pattern b1 having a size equal to or several times that of the transparent pattern (when the main pattern b1 has several times the size of the isolated pattern,
This mask is called a reticle) and a light-shielding film b having a translucent auxiliary pattern b2 formed around the mask.
And the phase of the exposure light which is made of a transparent material having a high refractive index such as silicon oxide and which is provided at the auxiliary pattern b2 forming portion of the light shielding film b and which passes through the auxiliary pattern b2 is displaced (shifted) by about 1/2 wavelength. The phase shift layer c and the main part thereof are configured, and this phase shift mask with an auxiliary pattern has a main pattern b1 of the same size as the isolated pattern.
In the case where the main pattern b1 is formed, the photosensitive resin film formed on the semiconductor substrate is exposed through the phase shift mask, and when the main pattern b1 is several times larger than the isolated pattern. Is exposed to light through the reduction optical system between the phase shift mask and the photosensitive resin coating.

The exposure light which has passed through the main pattern b1 of the phase shift mask with the auxiliary pattern (see FIG. 4A) shows the amplitude of the mountain-shaped distribution as shown in FIG. Since the phase of the exposure light passing through b2 is inverted by the action of the phase shift layer c, the exposure light exhibits a valley-shaped distribution amplitude as shown in FIG. Then, as a result of the exposure light passing through the main pattern b1 and the exposure light passing through the auxiliary pattern b2 interfering with each other, a light intensity distribution as shown in FIG.

As is clear from the comparison between FIGS. 4B and 4D, the exposure light passing through the main pattern b1 of the mask having the auxiliary pattern b2 is the main pattern b1 of the mask without the auxiliary pattern b2. The light intensity distribution is steeper than that of the exposure light passing through, and the main pattern b1 can be accurately reproduced on the photosensitive resin film. In order to prevent the auxiliary pattern b2 from being reproduced on the photosensitive resin film, the auxiliary pattern b
The size of 2 is set to such a fine pattern that optical resolution is difficult. For example, the line width is set on a 5 × reticle having a main pattern 5 times as large as an isolated pattern such as the above contact hole. Submicron fine pattern is set.

Such a phase shift mask with an auxiliary pattern is conventionally manufactured through the following steps. That is, as shown in FIG. 5, a light-shielding film b such as a chromium thin film is uniformly formed on a transparent substrate a such as quartz glass, and an electron beam resist (not shown) is applied on the light-shielding film b. A predetermined pattern is drawn by an electron beam drawing apparatus, and development processing is performed to form a resist pattern (not shown) having a predetermined shape. Next, the light shielding film b exposed from the resist pattern is removed by etching to form the main pattern b1 and the auxiliary pattern b2 (see FIG. 6), and the phase shift layer is formed on the auxiliary pattern b2 forming portion of the light shielding film b. c is formed to manufacture the phase shift mask with the auxiliary pattern (see FIGS. 2 and 3).

[0007]

In the conventional manufacturing method, in order to ensure the quality of the manufactured phase shift mask with an auxiliary pattern, the main pattern b1 and the auxiliary pattern b2 are formed before forming the phase shift layer. The formed light-shielding film b is irradiated with light rays, and the transmitted light pattern is inspected by an inspection device to detect the presence or absence of defects in the main pattern b1.

However, the auxiliary pattern b2 formed on the light-shielding film b is set to an extremely fine pattern as described above, and it is difficult to detect such a fine pattern by optical inspection. There is a problem that the auxiliary pattern b2 is recognized as a defect.

Therefore, in the conventional method, the above inspection is carried out with the inspection accuracy lowered to the extent that the auxiliary pattern b2 is not recognized as a defect. However, if the level of inspection accuracy is lowered, it is impossible to detect a sub-micron defect which is an original defect, and there is a problem that reliability of the phase shift mask with an auxiliary pattern is reduced.

The present invention has been made by paying attention to such a problem, and an object thereof is to provide a manufacturing method capable of reliably manufacturing a high quality phase shift mask with an auxiliary pattern. .

[0011]

That is, the invention according to claim 1 has a transparent substrate, a translucent main pattern provided on the transparent substrate, and a translucent auxiliary pattern formed around the transparent main pattern. Based on the method for manufacturing a phase shift mask with an auxiliary pattern, which includes a light shielding film and a phase shift layer provided in the auxiliary pattern forming portion of the light shielding film and displacing the phase of exposure light passing through the auxiliary pattern, on the transparent substrate The light-shielding film uniformly formed on the surface is patterned to form a main pattern, the light-shielding film on which the main pattern is formed is inspected for defects, and if there is a defect, the defect is repaired. After that, the light shielding film is patterned again to form an auxiliary pattern, and a phase shift layer is formed on the auxiliary pattern forming portion of the light shielding film. Than it is.

[0012]

According to the first aspect of the invention, when the light-shielding film on which the main pattern is formed is irradiated with a light beam to inspect for defects, an auxiliary pattern is formed on the light-shielding film during this inspection. Therefore, even if the inspection level in the optical inspection apparatus is set high, the auxiliary pattern is not recognized as a defect, and the original defect can be detected with high accuracy.

When a defect is found by inspection, the defect is repaired and then the auxiliary pattern is formed. Therefore, it is possible to stably manufacture a phase shift mask with a defect-free auxiliary pattern. Become.

[0014]

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

A chromium thin film 2 constituting a light-shielding film is formed on a transparent substrate 1 by a sputtering method, and an electron beam resist r is uniformly applied on the chromium thin film 2 (FIG. 1).
(See A).

Next, a main pattern having a shape similar to that of a semiconductor contact hole and having a size five times larger than that of the contact hole of a semiconductor is drawn on the electron beam resist r by an electron beam drawing apparatus, developed, and then patterned electron is formed. The chromium thin film 2 exposed from the line resist was removed by etching to form a main pattern 2a on the chromium thin film 2 (FIG. 1).
(See B).

Next, when a light beam is applied to the chromium thin film (light-shielding film) 2 on which the main pattern 2a is formed and the transmitted light pattern is inspected by an optical inspection device, the size sub-pattern is formed in the main pattern 2a. A residual chromium film (chromium film that remains as a defect without being removed during the etching process) 21 of about micron is detected, and also in the chromium thin film (light-shielding film) 2 other than the main pattern 2a forming portion. A pinhole (a fine hole as a defect formed during the formation of the chromium thin film or during the etching process) 22 having a submicron size was detected.

Therefore, the residual chromium film 21 in the main pattern 2a is irradiated with a YAG laser to be evaporated and removed, and the pinhole 22 is coated with the black ink 3 to remove these defects. Repaired (Fig. 1
(See C).

Next, the restored chromium thin film (light-shielding film) 2
The above-mentioned electron beam resist is uniformly applied to the entire surface including, the auxiliary pattern shape is drawn on the electron beam resist by the electron beam drawing apparatus, and after development, a chromium thin film exposed from the patterned electron beam resist. 2 is removed by etching, and the auxiliary pattern 2b is formed on the chromium thin film 2.
Were formed (see FIG. 1D).

The optical thickness of the chrome thin film (light-shielding film) 2 on the auxiliary pattern 2b is about 1 of the exposure light.
Phase shift layer 4 made of silicon oxide set at 1/2 wavelength
To form a phase shift mask with an auxiliary pattern (see FIG. 1E).

It was confirmed that the thus obtained phase shift mask with an auxiliary pattern was extremely reliable without any fine defects.

[0022]

According to the invention of claim 1, even if the inspection level in the optical inspection apparatus is set high, the auxiliary pattern is not recognized as a defect, and the original defect can be detected with high accuracy. In addition, if a defect is found by inspection, the auxiliary pattern is formed after the defect is repaired, so that it is possible to stably manufacture a defect-free phase shift mask with an auxiliary pattern. Become.

Therefore, there is an effect that a high quality phase shift mask with an auxiliary pattern can be manufactured with high reliability.

[Brief description of drawings]

1A to 1E are explanatory views showing a manufacturing process of a phase shift mask (reticle) with an auxiliary pattern according to an embodiment.

FIG. 2 is a schematic plan view of a phase shift mask with an auxiliary pattern.

FIG. 3 is a sectional view taken along the line III-III of FIG.

4A is a cross-sectional view of a phase shift mask with an auxiliary pattern, FIG. 4B is a graph showing the amplitude of exposure light that has passed through a main pattern of a phase shift mask with an auxiliary pattern, and FIG. FIG. 4C is a graph showing the amplitude of the exposure light passing through the auxiliary pattern, and FIG. 4D is a graph showing the light intensity distribution of the exposure light passing through the main pattern and the auxiliary pattern of the phase shift mask with the auxiliary pattern.

FIG. 5 is an explanatory view showing a manufacturing process of a conventional phase shift mask with an auxiliary pattern.

FIG. 6 is an explanatory view showing a manufacturing process of a conventional phase shift mask with an auxiliary pattern.

[Explanation of symbols]

 1 Transparent Substrate 2 Chrome Thin Film 2a Main Pattern 2b Auxiliary Pattern 4 Phase Shift Layer

Claims (1)

[Claims] 1. A light-shielding film having a transparent substrate, a light-transmitting main pattern provided on the transparent substrate, and a light-transmitting auxiliary pattern formed around the transparent main pattern, and the auxiliary pattern forming portion of the light-shielding film. In a method of manufacturing a phase shift mask with an auxiliary pattern, which comprises a phase shift layer for displacing a phase of exposure light passing through the auxiliary pattern, patterning a light-shielding film uniformly formed on the transparent substrate. A main pattern is formed, and the light-shielding film on which the main pattern is formed is inspected for defects. If there is a defect, the defect is repaired, and then the light-shielding film is patterned again to form an auxiliary pattern. A method of manufacturing a phase shift mask with an auxiliary pattern, which comprises forming the phase shift layer on the light shielding film at the auxiliary pattern forming portion.