JPH02101464A - Pattern forming method - Google Patents

Abstract

PURPOSE:To enable a good-shaped fine pattern to be formed by using excimer laser beams, electron beams, and X-rays by forming a lower layer made of a resin sensitive to a first radiation and an upper layer made of a resin sensitive to a second radiation interrupting or transmitting the first radiation. CONSTITUTION:The lower layer made of the resin 2 sensitive to the first radiation and the upper layer made of the second resin 4 sensitive to the second radiation, such as excimer laser beams, far ultraviolet rays, and X-rays, and intercepting or transmitting the first radiation are formed on a substrate 1, and the layer of the resin 4 is selectively exposed to the second radiation, such as KrF laser beams 6, next, uniformly exposed to the first radiation 7, such as ultraviolet rays (g lines), and both layers are selectively developed with the developing solution for the resin 2 at the same time, thus permitting the resin 4 of the upper layer to serve as a contact mask 5 at the time of the uniform exposure to the first radiation, and accordingly, a good-shaped pattern 9 to be easily obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to phosphorography technology for semiconductor manufacturing, etc., and relates to a method for forming fine patterns.

2. Description of the Related Art As a phosphorography technique for semiconductor manufacturing, it has been proposed to use an excimer laser as a light source. (For example, V, Pol at al, Proc, of 5PIE
.

833.8 (1986)) Excimer laser phosphorography is expected to have high resolution by taking advantage of its short wavelength.
At present, there is no optimal resist for this purpose, making it difficult to form a well-shaped pattern. FIG. 2K shows a conventional pattern forming method using an excimer laser. On the hydrophobically treated substrate 1, a deep ultraviolet positive resist MP2400 (Sibley) was applied 1.
A resist film 8 was obtained by applying 2 μm and prebaking at 90° C. for 2 minutes. (Fig. 2(a)) KrF (24 nm) excimer laser beam 6 is selectively applied via −ry, ray 6.
A pattern was formed by irradiating the film with 150 mJ/ad of N, 0.35 mm (mu) (Fig. 2(b)'), and developing with a 20% alkaline developer of MP2401.

(Figure 2 (C)) In a method that exceeds the problem to be solved by the invention, since the optical surface absorption of the resist is large,
The excimer laser light that entered from the edge of the mask 6 eroded the portion that should be the last exposed area, and the resulting 0.4 μm pattern 8 had a large film loss (40 to 60%).
The defect was almost triangular in shape.

When such defective patterns are used in the manufacture of semiconductor devices, they lead to a decrease in the yield of devices, which is a cause for concern.

Furthermore, commercially available resists for electron beam exposure usually have little dry etching resistance, and G-line (43 snm), which has a proven track record.

It is extremely difficult to use in a mass production process, similar to the ultraviolet resist used for 1.99 (3 asnm). Since the amount of data to be processed is large, data inversion is necessary, but currently there is no useful pattern inversion method. This problem also occurs in X-ray exposure.

The present invention improves the pattern shape, resolution, and
The purpose is to widen the process tolerance.

Means for Solving the Problems The present invention utilizes excimer laser, electron beam (ICB) and
In order to form fine patterns with good shapes using lines,
We devised the following method.

That is, the lower layer is irradiated with a first radiation-sensitive resin, such as a conventional ultraviolet resist, and the upper layer is irradiated with a second radiation, such as deep ultraviolet rays such as excimer laser light, electron beams, or X-rays. A second radiation-sensitive resin that is light-blocking or transparent to the first radiation is formed, selectively exposed to the second radiation, and then the entire surface is irradiated with the first radiation. This is a pattern forming method using a layered radiation-sensitive resin, in which the radiation-sensitive resin is developed simultaneously and selectively with a developer of the radiation-sensitive resin.

According to the present invention, the second radiation-sensitive resin whose transmittance decreases or increases with respect to the first radiation to which the lower layer is sensitive due to the second radiation which is sensitive to the upper layer resist, When exposing the entire surface to light, it acts as if it were a contact mask, making it easy to obtain a well-shaped pattern and image reversal and normal rotation.

Furthermore, as a new effect, the second radiation exposure that determines the pattern shape and resolution is prevented from scattering and reflection from the underlying substrate, and the two-layer structure improves flatness and enables long-distance exposure. In addition, in excimer, EB, and X@exposure, if a UV resist is used as the first lower layer resin, it is a useful process with a proven track record and dry etch resistance. It is promising as

Then, when the entire surface is exposed to the first radiation, a contrast enhancement effect occurs in the area selectively exposed to the second radiation, so that the resolution also improves0.Finally, the second radiation-sensitive resin is applied. By making the first radiation-sensitive resin soluble in the developer, one development with the first developer is sufficient.

Here, for example, when exposing a material whose transmittance in the ultraviolet region is reduced by deep ultraviolet light in the upper layer, it is possible that the light (deep ultraviolet light) passes through the ultraviolet resist in the lower layer. (For example, the sensitivity of M P / 400 ultraviolet resist to KrF excimer laser light is 10 J/ad or more)
Therefore, the lower ultraviolet resist is not exposed to deep ultraviolet light, which will not lead to defective pattern formation.

Examples Examples of materials whose transmittance in the ultraviolet region is reduced by deep ultraviolet light in the upper layer include a film containing a leuco compound as a main component.

Leuco compounds are generally well-known as substances with 7 otochromic effects, and here we will discuss triphenylmethane-based, phthalide-based, fuk-, t-ran-based, spirocyclic compounds, tetrazolium salt-based, complex leuco compounds, etc. Conceivable.

(CH,)2N0-N=N-C)-NH-GO-C)-
=NO-CH0-N=R ■■ is an acyl group such as OCH3 COCH2C15 CH3 CH,0 CH5, etc.

The steps of a pattern forming method according to an embodiment of the pattern forming method of the present invention will be described with reference to FIG.

A UV resist MP1400 (Sibley Co., Ltd.) is applied to a thickness of 1.2 μm on a substrate 1 such as a semiconductor that has been subjected to hydrophobic treatment, and a resist film 2 is obtained by prebaking for 90 minutes (Fig. Next, a material according to the invention having the following composition was applied. Since this material is water-soluble, it was possible to overcoat the UV resist 2. After baking at 80'C for 2 minutes, a 0.5 μm film 4 was obtained (
Figure 1(b)).

1.3.3-) Dimethylindolino-6'-nitrospiropyran 5! ! pullulan resin
10g water
Selectively emit KrF excimer laser light 6 at 250 rnJ/c4 through a 6og mask 6.
Irradiation (N, mu 0.36) was performed.

(FIG. 1(C)) As a result, the portion 20 irradiated with the laser beam 6 becomes a region that is opaque to the ultraviolet rays to be irradiated later. The entire surface was irradiated with G-line (436 nm) light 7, which is ultraviolet light, at 2somJ/cn. (FIG. 1(d)) At this time, the irradiation section 2o serves as a contact mask for the light 7, and the resist 2 is selectively exposed to the light 7. Finally, resist 2 was developed using MF319 alkaline developer (Sibley) and exposed to laser light 6.
The pattern was obtained by removing the part. (FIG. 1 (θ)) The two resist patterns obtained were steep line-and-space patterns of 0.4 μm and an aspect ratio of 90′.

In this example, instead of the material according to the present invention, RU-11 made of a commercially available azide compound and phenol resin was used.
Similar good results were obtained using 00N (manufactured by Hitachi Chemical).

In place of the excimer laser light, which is far ultraviolet light, in the above embodiments, electron beam exposure was selectively used at 2°xev, soo.
Similar results were obtained under the conditions of μC/d. Also, instead of excimer laser light, X-ray exposure can be selectively
Similar results were obtained under the conditions of J/d.

Effects of the Invention According to the method of the present invention, a fine resist pattern with a good shape can be obtained, which leads to an improvement in the yield rate of device manufacturing and is of high industrial value.

[Brief explanation of drawings]

FIG. 1 is a process sectional view of an embodiment of the pattern forming method of the present invention, and FIG. 2 is a process sectional view of a conventional pattern forming method. 1...Substrate, 2...UV resist)
(MP1400), 4... Material according to the present invention,
5... Mask, 6... KrF excimer laser light, 7... Ultraviolet light (g-line), 2...
···pattern. Name of agent: Patent attorney Shigetaka Awano and one other person

Claims (2)

[Claims] (1) forming a first radiation-sensitive resin sensitive to a first radiation on a substrate; and forming a first radiation-sensitive resin sensitive to a second radiation on the first radiation-sensitive resin; a step of forming a second radiation-sensitive resin having radiation shielding properties or transparency to the first radiation after exposing the first radiation; a step of selectively exposing the second radiation; and a step of selectively exposing the first radiation to the first radiation. The method is characterized by comprising the steps of: exposing the entire surface of the first and second layered radiation-sensitive resins; and selectively developing and removing the first and second radiation-sensitive resins. Pattern formation method. (2) The pattern forming method according to claim 1, wherein the second radiation-sensitive resin is a resin containing a leuco compound.