JPH03226758A - Pattern forming method - Google Patents

Abstract

PURPOSE:To enhance dimensional stability and reproduction performance by disclosing the acid, generated by irradiation with radiation in a resist film and having catalyticaly acted for patterning the resist, in an atmosphere containing a basic gas to stop the catalytic action. CONSTITUTION:The patterns 12' and 13' are obtained in a silicon oxide film 12 and a polysilicone layer 13 by forming on a semiconductor substrate 11 those films 12, 13 by the CVD method, coating the layer 13 with the resist 14 containing a compound to be allowed to generate the acid by radiation irradiation, irradiating the resist 14 with the radiation 16 through a proper mask 15 in a laser exposure device, heat treating it on a hot plate, immediately disclosing it to an atmosphere containing gaseous ammonia, developing it to obtain a pattern 14', using it as a mask, and etching the films 12, 13, thus permitting the residue of the acid having finished the catalytic action in the resist patterning process to be treated by the NH3-containing atmosphere to prevent the catalytic action, consequently, dimensional stability and reproduction performance to be enhanced.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present description relates to a pattern forming method.

(Prior Art) Recently, it has been known that during pattern formation on a substrate, acid generated in the resist film due to radiation irradiation on the resist film during exposure catalyzes the Renost shape formation mechanism (
For example, J, Ph01OpO1! /II.

Sci, Techol, 2(3), 429(19
89)).

According to this method, since the reaction system is catalytic, image formation is possible with less irradiation energy.

However, the acid generated by radiation irradiation has a catalytic effect that promotes the reaction between the resin used as the resist film and the crosslinking agent, and the generated acid continues to act in the reaction system as long as it is present in the film. (for example, Proc
eeding or AaerfcanChemjca
151 (1989))
However, it has the drawback of decreasing dimensional stability and reproducibility.

(Problem to be Solved by the Invention) As described above, when acid is generated in the resist film due to exposure to light, the acid acts as a catalyst for the resist shape formation mechanism, but this action continues as long as the acid exists. There was a problem in that dimensional stability and reproducibility were reduced.

In view of the above points, it is an object of the present invention to provide a pattern forming method in which the acid generated in the resist film is removed after the acid has catalyzed the resist shape forming mechanism.

[Structure of the Invention] (Means for Solving the Problems) A pattern forming method according to the present invention includes a step of applying a resist film containing a compound that generates an acid when exposed to radiation onto a substrate, and irradiating the resist film with radiation. The method is characterized by comprising a step of forming a latent image, a step of exposing the resist film and the substrate to a basic atmosphere, and a step of developing and patterning the substrate with the resist film.

(Function) In this pattern forming method, the catalytic action of the acid generated in the resist film by radiation, which acts as a catalyst to form a resist shape, is exposed to a basic gas atmosphere after radiation irradiation. stop.

(Example) Embodiments of the present invention will be described below with reference to FIG.

FIG. 1 is a cross-sectional view showing the pattern forming method according to the present invention in the order of steps.

First, Fresol novolak resin, melamine resin, and an organic halogen compound (for example) as an acid generator were mixed in a weight ratio of 7.5:2. After mixing and dissolving in 1=acetoxy-2ethoxyethane at a ratio of o:o, 5, 0.2 μm
Adjust the negative resist through a pore size filter. Next, a film with a thickness of 0 is deposited on the semiconductor substrate 11 using the CVD method.
．． A silicon oxide film 12 with a thickness of 0.02 μm is formed. Then, from above, a 0.4 μm polysilicon layer 13 is formed using the CVD method.
form. Next, apply a resist 13 of 0.5 μm from above.
The coating is applied to a film thickness of m (FIG. 1(a)).

Next, radiation 16 is passed through a suitable mask 15 using a KrF excimer laser exposure device with a resist numerical aperture of 0.37.
(Fig. 1(b)).

After that, heat treatment was performed on a hot plate at 110°C for 1 minute, and then immediately exposed for 30 seconds in an NH and gas atmosphere.
TMAR (tramethylammonia hydroxide)2.
After development in a 38% by weight solution for 60 seconds, a pattern image 14- is obtained (FIG. 1(C)).

Next, etching is performed using the pattern image 14' as a mask to obtain patterns 12' and 13' of the insulating film 12.13 (
Figure 1(d)).

According to this embodiment, in order to prevent the catalytic action of the acid that remains after the acid generated in the resist film by radiation irradiation performs the catalytic action of the resist shape forming mechanism as in the conventional example, NH , since it is processed in an atmosphere, it overcomes the drawbacks of the prior art and improves dimensional stability and reproducibility. Utilizing this, the yield of devices can be improved.

Note that in this example, a deposited layer was formed on the semiconductor substrate, but
The resist may be applied directly to the semiconductor substrate. Furthermore, the basic gas used is not limited to NH and gas. Further, although pattern formation was performed through a mask, the mask may not be used when direct drawing is performed using an electron beam.

In addition, in this example, acid is generated in the resist film by radiation and the resin crosslinks or polymerizes during processing before development (negative type), but the resin decomposes (negative type). Positive type) is also acceptable.

Note that this embodiment can be used not only for forming patterns on semiconductor substrates but also for manufacturing masks and liquid crystals.

[Effects of the Invention] From the above results, by using the pattern forming method of the present invention, the acid generated in the resist film due to exposure can be
After performing the catalytic action of the resist shape forming mechanism, the acid that remains in the resist film stops performing the catalytic action, thereby improving dimensional stability and Δ reproducibility.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a pattern forming method according to an embodiment of the present invention in the order of steps. 11... Semiconductor substrate, 12... Silicon oxide film, 1
3... Polysilicon layer, 14... Resist film, 15
...Mask, 16...Radiation.

Claims (2)

[Claims] (1) A step of applying a resist film containing a compound that generates an acid when exposed to radiation onto a substrate, a step of irradiating the resist film with radiation to form a latent image, and a step of applying a basic gas to the resist film and the substrate. A pattern forming method comprising the steps of exposing the substrate to an atmosphere, and developing and patterning the substrate with the resist film. (2) The pattern forming method according to claim (1), further comprising the step of heat-treating the substrate after forming the latent image on the resist film.