JPH01147457A - Formation of pattern for semiconductor device - Google Patents

Abstract

PURPOSE:To process a fine pattern by providing a slit on the outer periphery of the light shielding region of a photomask. CONSTITUTION:The slit B which is not resolvable is formed at the inside of a shielding pattern A along the outer peripheral area as a light shielding pattern formed on the photomask surface, and the fine pattern is formed by using the light shielding pattern possessing such slit. Thus, the light passed through the slit is detoured around the light transmissive region which originally requires exposure, and when the exposure quantity is not enough owing to the fine light transmissive region, a photo resist is exposed with the light quantity supplement, and the fine pattern is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Application Field The present invention relates to a method for forming a pattern in the manufacturing process of a semiconductor device, and more particularly to a method for forming a pattern by exposure and development using a photomask.

<Prior Art> As semiconductor devices have become more densely fabricated on semiconductor substrates, the dimensions of the elements themselves have become much finer. Such fine processing has been addressed by improving the photoresist, developer, or exposure device used in the pattern bursting process.

Problems to be solved by the invention
Improvements in resolution are being attempted by developing high-resolution photoresists with completely improved additives added to photosensitive materials and by increasing the NA (lens aperture diameter) as shown in the following equation (with respect to exposure equipment).

(R = theoretical resolution) (FD = depth of focus) However, in actual semiconductor devices, steps are created by oxide films, conductors, etc. formed on the surface, and the black dot coincidentally aligns with both the top and bottom of the steps. The morning area was narrow, and there was a problem in improving resolution.

If the wavelength of the light source used for the fLLJi light is shortened, the theoretical resolution will be similarly improved, but the lens design will become difficult and selection of the lens material will also become difficult.

CEL technology has been proposed to improve the resolution by alleviating the diffraction effect of surface light, but this has the problem of increasing the number of steps and increasing costs.

The present invention has been made in view of the above problems, and provides a pattern forming method that enables processing of fine patterns without reducing resolution.

Means for Solving the Problems> The present invention provides a light shielding pattern formed on a photomask surface in the step of patterning a single-layer photosensitive material coated on a semiconductor substrate. All the slits are formed to such an extent that they cannot be resolved, and a fine pattern is formed using a light-shielding pattern having such slits.

Function> Since the microscopic strip (f) is provided along the outside of the light-shielding pattern, the light that passes through the strip (k) will wrap around the translucent area that originally requires exposure, and even if the translucent area is microscopic. Therefore, even if there are few exposure meters, the photoresist can be exposed with supplementary light arsenic to form a desired pattern.

<Embodiment> FIG. 1 shows a photomask pattern of an embodiment of the present invention, in which the shaded area A formed on the surface of a transparent plate such as glass is a light-shielding area formed by patterning a chrome film or the like.

As shown in the figure, the above-mentioned light-shielding area A has a light-transmitting width Δt without a light-shielding film at a position that is a minute distance Δt inward from the outside.
A slit B consisting of is formed outwardly.

Here, the values confirmed by the inventor through experiments are that Δt is designed to be about 0.5 μm and Δ is designed to be about 0.2 μm, without resolving the pick-pocket throat.
The best pattern could be formed between the two.

That is, when exposure is performed according to the above pattern, the light irradiated to the adjacent light-shielding region A and the light-transmitting region C located at Aif'l is transmitted to produce photoresist light. Here, if the pattern is fine, the width of the transparent area C will be extremely small,
Therefore, the amount of exposure light is too small and the photoresist cannot be sufficiently exposed, causing problems in the formation of fine patterns. However, as described above, by providing the slit B in one area outside the light-shielding area, the light transmitted through the slit B goes around and replenishes the light-transmitting area C, thereby increasing the resolution of the pattern.

In Figure 2, the width of the transparent area C in the photomask is 0.7μ.
m, 0.9 μm, and when there is no slit, slit IJ =
B) It shows the cooling between the exposure time when the i film is formed and the thickness of the transparent area C after development, and the development limit value is lower and finer for any line width when the slit B is provided. This shows that five-drug processing is possible.

In the step of forming a pattern on the photoresist on the semiconductor substrate using the photomask in which the slits B are formed, a positive resist is applied on the semiconductor substrate and then heat-treated to remove the solvent remaining in the photoresist 19. volatilize. Next, the above slit B is placed on the photoresist film.
Expose with ultraviolet rays, etc. with full photomasks facing each other,
The photoresist is developed using a developer such as an organic solvent to form a pattern corresponding to the outside of the light-shielding area A of the photoresist.

For example, the base SiN/5i02 before LOG OS film formation
When the above pattern forming method is applied, the device width due to LOCO5 is at least 0.1 to 0.1% compared to pattern formation using a photomask in a light-shielding area without any slits.
d could be reduced to 0.15 μm.

<Effects> According to the present invention, by adding a simple configuration, it becomes possible to process fine patterns, and it is possible to further increase the density of the semiconductor device.

[Brief explanation of the drawing]

FIG. 1 is a photomask pattern diagram showing one embodiment of the present invention, and FIG. 2 is a diagram showing the relationship between exposure time and pattern line width during an exposure process to which the present invention is applied.

Claims (1)

[Claims] 1. In a method in which a photosensitive layer deposited on a semiconductor substrate is exposed to light through a photomask and developed to form a pattern on the photosensitive layer, a light-shielding portion formed on the photomask is formed on the outer periphery of the light-shielding portion. 1. A method for forming a pattern for a semiconductor device, comprising: forming a light-transmitting slit at a position that penetrates inward at a minute interval, the size being smaller than the amount of penetration.