JPH0451151A - Production of phase shift reticle - Google Patents

Abstract

PURPOSE:To prevent the misregistration of patterns at the time of overlap exposing with an electron beam by successively coating a reticle substrate with a light shielding film and resist film and exposing the exposing parts of the resist film by the electron beam without decreasing a residual film rate to zero, then reexposing only the shifter part on the peripheral edge of the exposed part, thereby patterning the resist film. CONSTITUTION:The reticle substrate 1 is coated with a chromium film as the light shielding film 2 by a sputtering method and is coated with the resist film 3 for the electron beam by a spinner. The exposing part 4 of the resist film 3 is exposed by the electron beam 5 at the dosing quantity determined in such a manner that the residual film rate of the resist film 3 after the exposing and developing attains 50%. In succession, only the shifter part 7 on the peripheral edge of the exposing part 4 is again exposed at the same dosing quantity. The Cr film 2 of the shifter part 7 is etched away with the resist film 3 as a mask and in succession, the glass substrate 1 of the shifter part is etched. The resist film 3 is ashed away until the Cr film 2 on the exposing part 4 is exposed to remove the resist film 3 on the glass substrate 1. The misregistration of the patterns at the time of the overlap exposing by the electron beam is prevented in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a method for manufacturing a reticle used for one-phase shift exposure.

Regarding the layer formation method.

The purpose is to prevent pattern misalignment during electron beam overlapping exposure when manufacturing phase shift reticles.

A step of sequentially coating a reticle substrate with a light shielding film and a resist film, exposing the exposed part of the resist film to an electron beam without reducing the remaining film rate to zero, and then re-covering only the shifter part at the periphery of the exposed part. A step of exposing the exposed resist film, a step of developing the exposed resist film, and a step of etching the reticle substrate of the shifter portion to a predetermined depth using the resist film as a mask.

A step of removing the resist film by ashing until the light shielding film on the exposed portion is exposed, a step of etching and removing the light shielding film on the exposed portion, and a step of removing the resist film on the reticle substrate. It is constituted by including a process.

(Industrial Application Field) The present invention relates to a method for manufacturing a reticle used for one-phase shift exposure.

In recent years, as semiconductor devices have become more highly integrated and finer, elements have been manufactured (mask patterns have become more highly integrated, and pattern microfabrication techniques are required.

Therefore, it is necessary to improve the pattern resolution.

[Conventional technology]

FIG. 2 is a conceptual diagram of the phase shift method, and FIG. 3 is an explanatory diagram of a conventional example.

In the bacteria, 8 is glass, 9 is a mask pattern 10 is an exposure part, 11 is a light, 12 is a light shielding part, 13 is a shifter 14 is a glass plate, 15 is a chrome film, and 16 is a resist film.

17 is an electron beam, 18 is an exposure part, 19 is a shifter 2
0 is a resist film.

Techniques for improving the resolution of mask patterns include methods of increasing the contrast of the mask pattern irradiated onto the resist, methods of improving contrast by controlling the development speed, methods of improving contrast using reactions near the surface of the resist, and resist multilayering. There are contrast improvement methods using films, etc., and ways to improve the contrast of mask patterns include increasing the numerical aperture of the optical system or shortening the transfer wavelength.

However, this method has various problems with the device, and it is difficult to solve them.

For this reason, a one-phase shift method has been devised as a method for improving the contrast of a mask pattern. this is,
As shown in FIG. 2(a), a repetitive mask pattern 9 like lines and spaces formed on the glass 8.
In this case, depending on the phase of the light 11 emitted from the adjacent exposure section 10, the light also bleeds into the light shielding section 12, the difference in light intensity is attenuated, and the contrast of the mask pattern 9 is reduced. ), when the shifter 13 is provided in the exposure section 10 and the phase of the light emitted from above the adjacent exposure section is reversed by 180 degrees, the exposure section provided with the shifter 13 and the conventional exposure section 10 are This is based on the principle that the light intensity of the sandwiched light shielding part 12 becomes zero and the adjacent exposure parts 10 are separated.

By this method, fine patterns of 0.3 μm level, which were difficult to resolve with conventional i-line exposure equipment, can be sufficiently resolved, and it is also an effective means for improving the depth of focus.

FIG. 3 shows a method of manufacturing a reticle used in conventional phase shift exposure.

First, as shown in FIG. 3(a), a chromium film 15 is deposited on a glass plate 14 for a reticle substrate to a thickness of several hundred holes by sputtering, and a resist film 16 is applied using a spinner. Next, using the electron beam 17, the resist film 16 is
to expose.

Next, as shown in FIG. 3(b), the resist film 16 is developed to remove the resist film 16 in the exposed portion 18, and then, using the resist film 16 as a mask, the chromium film 16 in the shifter 19 portion is removed. The shifter 19 is formed by etching the glass plate 14 to a depth of several hundred holes.

Thereafter, the developed resist film 16 is peeled off.

As shown in FIG. 3(c), a resist film 20 is applied again to the entire surface of the glass 8.

Furthermore, as shown in FIG. 3(d), the electron beam is used to superpose the exposed edge portion of the resist pattern so that the exposed edge portion thereof is placed on the shifter 13.

Finally, as shown in FIG. 3(e), the portions of the chromium film 15 without the resist film 20 are removed by etching, and the resist film 20 is peeled off to complete the phase shift reticle substrate.

However, the width of the shifter 130 is very narrow, on the order of submicrons, and there are problems with positional deviations due to charge-up due to electron beam exposure and positional deviations depending on the stage of the apparatus.

[Problem to be solved by the invention]

Therefore, a problem occurs in which the mask pattern is misaligned and the shifter section is misaligned, making it impossible to perform one-phase shift exposure.

The present invention is provided for the purpose of preventing pattern positional shift during electron beam overlapping exposure when manufacturing a two-phase shift reticle.

[Means for Solving the Problems] FIG. 1 is a diagram illustrating the principle of the present invention and a schematic sectional view in the order of steps of an embodiment.

In the figure, 1 is a reticle substrate, and 2 is a light shielding film.

3 is a resist film, 4 is an exposure section, 5 is a light shielding section for the electron beam 6, and 7 is a shifter section.

The above problem can be solved by changing the exposure amount of the glass pattern and the shifter part to create a step in the resist.

That is, one object of the present invention is to provide a light shielding film 2. on a reticle substrate 1, as shown in FIG. 1(a). As shown in FIG. 1(b), the exposed portion 4 of the resist film 3 is
is exposed to an electron beam 5 without reducing the residual film ratio to zero, and then only the shifter part 7 at the periphery of the exposed part 4 is exposed again. As shown in FIG. 1(C), the exposed resist film is The process of developing 3.

As shown in FIG. 1(d), using the resist film 3 as a mask, the reticle substrate 1 of the shifter section 7 is etched to a predetermined depth. a step of removing the film 3 by ashing until the light shielding film on the exposed portion 4 is exposed;

As shown in FIG. 1(f), the light shielding film 2 on the exposure section 4
and the process of removing it by etching.

This is achieved by including the step of removing the resist film 3 on the reticle substrate 1, as shown in FIG. 1(g).

(Function) In the present invention, as described above, electron beam exposure is performed in one exposure and patterning is performed, so the step of electron beam overlapping exposure is eliminated, and shifter part shift caused by the charge amplifier or device is eliminated. .

[Example] FIG. 1 is a schematic cross-sectional view of an example of the present invention in the order of steps.

As shown in FIG. 1(a), chromium (Cr) is used as a light shielding film 2 on a reticle substrate l made of a glass plate with a finch diameter.
The film was coated to a thickness of 600 mm by sputtering, and then EBR-9 was coated with a spinner to a thickness of 600 mm as a resist film 3 for electron beam use.

As shown in FIG. 1(b), the exposed portion 4 of the resist film 3 is exposed to an electron beam 5 at a dose determined so that the residual film ratio of the resist film after exposure and development is 50%. .

When EBR-9 is used as in this example, the dose is 8 μC/cm 2 .

Subsequently, only the shifter section 7 at the periphery of the exposure section 4 is removed again.
Exposure at the same dose.

As shown in FIG. 1(C), when the exposed resist film 3 is developed, 8,000 resist films remain as they are in the light shielding areas, and the resist is completely removed in the shifter areas 7 of the exposed areas 4. The resist film is removed, leaving a resist film with a thickness of 4,000 mm in other exposed areas.

As shown in FIG. 1(d), using the resist film 3 as a mask, the Cr film 2 of the shifter section 7 is removed by etching, and then the glass substrate 1 of the shifter section is etched to a depth of 500 mm.

As shown in FIG. 1(e), a resist film 3 is formed.

The Cr film 2 on the exposed portion 4 is removed by ashing by a thickness of 4,000 layers using an ashing device until the Cr film 2 is exposed.

As shown in FIG. 1(f), the Cr film 2 on the exposed portion 4 is removed by etching.

As shown in FIG. 1(g), the resist film 3 on the glass substrate 1 is removed to complete a one-phase shift reticle substrate.

[Effects of the Invention] As explained above, according to the present invention, the mask pattern layout can be improved and the precision of the single phase shift reticle can be increased.

Therefore, it greatly contributes to the establishment of two-phase shift exposure technology.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an embodiment of the present invention in the order of steps. FIG. 2 is a conceptual diagram of the phase shift method. FIG. 3 is an explanatory diagram of a conventional example. In the figure, l is a reticle substrate, and 2 is a light shielding film. 3 is a resist film, 4 is an exposure part 5 which is an electron beam, and 6 is a light shielding part. 7 is a shifter section of the present invention. figure

Claims (1)

[Claims] The reticle substrate (1) has a light shielding film (2), a resist film (
3) and exposing the exposed portion (4) of the resist film (3) to an electron beam (5).
a step of exposing without reducing the residual film rate to zero, and subsequently exposing only the shifter part (7) at the periphery of the exposed part (4) again; and a step of developing the exposed resist film (3). etching the reticle substrate (1) of the shifter section (7) to a predetermined depth using the resist film (3) as a mask; A step of removing the light shielding film (2) by ashing until the light shielding film (2) is exposed, a step of etching and removing the light shielding film (2) on the exposed portion (4), and a step of removing the resist film (3) on the reticle substrate (1). ).) A method for manufacturing a phase shift reticle, the method comprising: removing the phase shift reticle.