JPS62150350A - Formation of pattern - Google Patents

Abstract

PURPOSE:To form a desirable pattern with certainty by preventing the residue of a resist from being stuck and the residual resist pattern from remaining on a thin film without being peeled. CONSTITUTION:The thin base film is coated with the resist, exposed, and developed to form the resist pattern on the thin film. It is etched with an acid solution lower in temperature than the acid solution to be used in a step of peeling the residual resist pattern, and the residual resist pattern is immersed in the acid solution to render the pattern gradually hydrophilic from the surface layer and to swell it simultaneously, thus permitting the resist residue to be prevented from being stuck and the remaining resist pattern to be prevented from remaining on the thin film of Cr or the like without being peeled, and consequently, the desired pattern is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pattern forming method for forming a pattern by etching a light-shielding thin film or a thin film made of silicic oxide or the like on a substrate on which the thin film is coated. .

[Conventional technology]

Conventionally, in the case of manufacturing a photomask in a pattern forming method, for example, a photomask substrate is manufactured by depositing a light-shielding thin film such as a Cr film on a light-transmitting substrate, and then a negative mold is applied to the light-shielding thin film. A resist-coated photomask substrate is manufactured by coating the negative electron beam resist with an electron beam resist, and the negative electron beam resist is exposed to light using an electron beam writing equipment to form a latent image of a predetermined resist pattern. In order to form a predetermined residual resist pattern on the thin film, it is developed with a developer for a predetermined period of time, and then rinsed with a rinsing solution of a type different from the developer. Thereafter, this photomask substrate with the remaining resist pattern is rotated at high speed and dried using a spin drying method in which the rinsing solution is shaken off and removed by centrifugal force, and then immersed in an etching solution corresponding to the light-shielding thin film for a predetermined time. Then, the exposed light-shielding thin film is etched. Then, the remaining resist pattern and the light-shielding thin film pattern thereunder remain on the light-transmitting substrate constituting the photomask substrate. Rough, liquid) ￥A70-150
℃ in a resist stripping solution (e.g. Kitai solution consisting of sulfuric acid and hydrogen peroxide solution) to peel off the remaining cyst pattern and form a predetermined light-shielding thin film pattern on the light-transmitting substrate. and was making photomasks.

[Problems to be Solved by the Invention] However, when forming a pattern as described below, if the remaining resist pattern is removed using a resist stripping solution with a high liquid temperature of 70 to 150°C, In particular, in the case of a negative resist with a highly cross-linked molecular structure such as a negative electron beam resist, the peeled residual rinse 1-
The pattern becomes a large amount of resist residue floating in the resist stripping solution. The reason why this resist residue is generated is that the surface layer of the remaining resist pattern is carbonized and hardened in the high temperature resist stripping solution, and the resist stripping solution acts on the interface between the remaining resist pattern and the Cr film. This is because the remaining resist pattern above the interface is completely peeled off.

If the above-mentioned resist residue is floating in the resist stripping solution, the resist residue will adhere to the mask substrate from which the remaining resist pattern is to be stripped.
Unable to form desired pattern.

In addition, as described above, when the surface layer portion of the remaining resist pattern is carbonized and hardened, if the degree of hardening is severe, the resist stripping liquid cannot act on the interface between the remaining resist pattern and the Cr film, and the remaining resist pattern is hardened. The resist pattern is not peeled off at all and remains on the Cr film, making it impossible to form a desired pattern.

The present invention has been made in view of the above circumstances, and it is possible to prevent the resist residue from adhering and to prevent the remaining resist pattern from remaining on a thin film such as a Cr film without being peeled off. It is an object of the present invention to provide a pattern forming method that can form a desired pattern while preventing the above problems.

[Means for solving problems]

The present invention has been made in order to achieve the above-mentioned object.A resist is applied on the thin film of a substrate on which the thin film is coated, and the above-mentioned rinse] is exposed and developed.
A residual resist pattern is formed on Q, the thin film is etched, and treated with an acid solution having a lower liquid temperature than the acid solution used in the peeling process of the residual resist pattern, which will be described later.
This pattern forming method is characterized by immersing the remaining resist pattern in an acid solution and peeling it off.

[For production]

When treated with an acid solution having a lower liquid temperature than the acid solution used in the process of stripping the remaining resist pattern, the remaining resist pattern gradually becomes hydrophilic from its surface layer and simultaneously swells.

[Example] This example shows an example of a pattern forming method when manufacturing a photomask.

First, a transparent substrate (material: diquartz glass, 7X
7X O, 12 inches), and one main surface -
A photomask substrate is manufactured by depositing a Cr film (optical temperature: 3.0, film thickness: 900) as a light-shielding thin film on F by sputtering. Next, a negative electron beam is applied onto this Cr film to form a di-1- (e.g. CMS-EX (SS))
(manufactured by Toyo Kodatsusha Co., Ltd.), film thickness: eooo material) was coated by a spin code method to produce a resist-coated photomask substrate.

Next, in order to form a latent image of a predetermined resist pattern on this resist, an electron beam drawing device (e.g., Perkin-Elmer HE) is used.
BES-II) and then developed by immersing it in a special developer for a predetermined time (e.g. 60 seconds) to remove the unexposed portion and form a predetermined residual resist pattern on the Cr film. . Next, the substrate is immersed in a rinsing liquid (eg, isobutylene alcohol solution) for rinsing, and then dried by a spin drying method in which the rinsing liquid is shaken off using centrifugal force.

Next, it is immersed in an etching solution (e.g., a mixed aqueous solution of ceric ammonium nitrate and perchloric acid) for a predetermined period of time (e.g.,
25 seconds) Dip and etch to etch the exposed Cr film. Then, the remaining resist pattern and the Cr film pattern thereunder remain on the light-transmitting substrate.

Next, the solution is immersed in a sulfuric acid solution with a liquid temperature of 30°C for a predetermined time (e.g. 210°C).
second) immersion and treatment with an acid solution, then immersion in a resist stripping solution made of an acid solution at a temperature of 80°C (e.g. a mixed solution of sulfuric acid and hydrogen peroxide solution) to peel off the remaining resist pattern. A photomask in which a predetermined Cr film pattern is formed on the transparent substrate 1D is manufactured.

0,
In the former case, there were about 200 resist deposits of 5 μm or more (adhesion of resist residues and unpeeled remaining resist patterns), but in the latter case, there were none or 2 or less.

As described above, the pattern forming method according to this embodiment
When the mask A1~ is manufactured, the remaining resist pattern becomes hydrophilic and swells because it is treated with an acid solution having a lower liquid temperature than the acid solution used in the process of peeling off the remaining resist pattern. Therefore, in the process of removing the remaining resist pattern, the remaining resist pattern dissolves from its surface layer and dissolves into the resist stripping solution. Since the pattern will not be peeled off and remain on the CR film, a photomask with a desired pattern formed thereon can be reliably manufactured.

The present invention is not limited to the embodiments described above.

The temperature of the sulfuric acid used in the acid solution treatment is not limited to 30°C,
The temperature is preferably within the range of 10 to 70°C, and the immersion time is also determined appropriately. In addition to sulfuric acid, hydrochloric acid.

Inorganic acids such as hydrogen peroxide and nitric acid, or silicic acid may also be used. Also, the temperature of the resist stripping tat'a was 8.
The temperature is not limited to 0°C, but can be appropriately determined at a liquid temperature higher than the liquid temperature of the acid solution used in the acid solution treatment.

In addition to quartz glass, the material of the transparent substrate may be multi-component glass such as aluminosilicate, borosilicate, soda lime, etc., and its dimensions are determined as appropriate. Furthermore, a substrate made of silicon, GaAS, or the like may be used instead of the light-transmitting substrate.

In addition to Cr film, Ta, No, and Ni can be used as light-shielding thin films.
.

Etchable metals such as NiCr, nitrides, carbides, oxides, silicides, etc. of these metals,
A multilayer film on two pairs of these may be used, and the film thickness is 90 mm.
The number of people is not limited to 0, and can be determined as appropriate according to a predetermined optical fJ degree. As a method for forming the light-shielding thin film, a vacuum evaporation method or an ion-blating method may be used instead of a sputtering method. Furthermore, a thin film made of silicic oxide or the like may be deposited on the substrate.

Instead of the negative type electron beam resist used in this example, a positive type electron beam resist, a negative type and a positive type photoresist, etc. may be used, but in particular, a negative type electron beam and photoresist]. For this purpose, the pattern forming method of this embodiment is effective. Further, the resist coating method may be a coating method such as a roll-to-1 method. Further, in the exposure step, exposure was performed with an electron beam, but negative type and positive type photoresists] may be exposed with ultraviolet light or deep ultraviolet light.

Further, as the rinsing liquid, an organic solvent other than isopropyl alcohol may be used. Further, in this example, development, rinsing and etching are performed by a dipping method, but a spray method or the like may also be used. Further, the rinsing step and the drying step are not essential and may be omitted. As the etching method, a dry etching method such as a plasma etching method, a sputter etching method, or an ion beam etching method may be employed.

The drying method is not limited to the spin drying method, and may be any other drying method capable of drying a substrate such as a photomask substrate or a semiconductor substrate coated with a thin film of silicic oxide.

Furthermore, the pattern forming method of the present invention can be applied to other pattern forming methods, such as when an integrated circuit is manufactured from a semiconductor substrate made of silicon with a thin film of silicic oxide coated on the substrate through a predetermined adhesive processing process. .

[Effects of the Invention] According to the pattern forming method of the present invention, it is possible to prevent resist residue from adhering, and to prevent the remaining resist pattern from @
By preventing the particles from remaining on the thin film without being separated, a desired pattern can be reliably formed.

Claims (1)

[Claims] (1) Applying a resist on the thin film of the substrate on which the thin film is applied, exposing and developing the resist, forming a residual resist pattern on the thin film, and etching the thin film;
A pattern forming method characterized by treating with an acid solution having a lower liquid temperature than the acid solution used in the step of peeling off the remaining resist pattern described later, and then immersing the remaining resist pattern in the acid solution and peeling it off.