JPS61151531A - Image forming material - Google Patents

Abstract

PURPOSE:To obtain an image forming material suitable for use in the formation of a fine pattern by combining a donor with a salt which acts as an oxidizing agent and then releases an anion capable of forming a charge-transfer complex with the donor by quick degradation when light is irradiated on the salt. CONSTITUTION:This image forming material contains an electron donating compound and an org. salt and/or an inorg. salt which is reduced with light and generates an anion. The material can form an image by the difference in color tone between the state of the mixture before the irradiation of light and a state after the formation of a charge-transfer complex by the irradiation of light. For example, when the donor and the photodegradable compound are dispersed in a polymer carrier or incorporated into the molecular skeleton of the carrier, an image can be formed by the difference in absorption in the ultraviolet and visible regions between light irradiated and unirradiated parts. An image can be also formed by the difference in solubility in an org. solvent between the state of the mixture before the irradiation of light and a state after the formation of a charge-transfer complex by the irradiation of the rays of light.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to novel imaging materials.

[Technical Background of the Invention] It is a well-known fact that a compound having electron-donating properties (donor) forms a charge transfer complex with an electron-donating compound (acceptor) or an inorganic anion. The method for producing such a charge transfer complex is as follows: 1. By mixing donor and acceptor solutions, a charge transfer complex is generated in the mixed solution and taken out as a crystal (mixing method) 2. In the same container A donor and an acceptor are placed at separate locations, and a solvent is filled in the container to disperse the donor and acceptor in the solution to form a charge transfer complex. (Diffusion method) 3. Donor, oxidizing agent such as hydrogen peroxide, and HPF6, HASF6
, HSbF6.

A method in which Shun, such as HBF4, coexists in a solution to oxidize the donor and simultaneously precipitate it as a salt.

4. Donor and AQPF6, (Pb)4CPF6
A method in which a charge transfer complex is precipitated by coexisting in a solution a salt that contains an anion that can form a trivalent salt with a donor, such as a salt that can itself act as an oxidizing agent.

5. A method in which a toner and an electrolyte containing an anion capable of forming a charge transfer complex with a donor are coexisting in a solution, and a charge transfer complex is formed by passing an electric current through the solution. (Electrolytic method) and other methods have been known for a long time.

A method for guiding a donor into a charge transfer complex by light irradiation and using it as an image forming material is described in Japanese Patent Application Laid-Open No. 56-6224.
As described in Japanese Patent No. 7, a method using a photoreaction with a donor and a polyhalocarbon was known.

The present invention provides (Ph)3SXa (Xa is SbF +
, PF −, AsF −, BF4 −.

Represents an anion such as Br-, CI-, I. ) for the photodecomposition reaction of tertiary sulfonium salts. TTF
In the process of examining the sensitizing effect of the donor, etc., the donor and 5bF- were irradiated with light to a solution in which the tertiary sulfonium salt and the donor coexist.

PF6-, AsF-, BF-, Br-, I-.

It was discovered that a charge transfer complex was formed with an anion such as C1'', and as a result of a rough and detailed study of this reaction, it was discovered that this reaction could be used in image forming materials, and the invention was completed.

[Object of the Invention] An object of the present invention is to provide an image forming material suitable for forming a fine pattern.

[Summary of the Invention] The present invention involves coexisting a donor and a salt that acts as an oxidizing agent when irradiated with light and then rapidly decomposes to release an anion that can form a charge transfer complex with the donor. An image is formed by irradiating light.

Next, the image forming method according to the present invention will be explained in more detail. First of all, this material can form an image due to the difference in color tone between the state of the mixture before irradiation with light and the state after formation of a charge transfer complex after irradiation with light. That is, for example, an image can be formed by dispersing the above-mentioned donor and photodegradable compound in a polymer carrier, or by incorporating them into a molecular skeleton, based on the difference in ultraviolet/visible absorption between the light-irradiated portion and the non-irradiated portion. According to this method, it is easy to create shading by changing the intensity of light irradiation.

This method allows images to be formed on plates or films of polymeric materials.

Secondly, an image can also be formed by utilizing the difference in solubility in an organic solvent between the mixture state before light irradiation and the complex formation state after irradiation.

That is, a layer of a donor and a photodegradable compound is formed on a plate or film, a light irradiated area and a non-irradiated area are formed through an appropriate mask, a charge transfer complex that is poorly soluble in an organic solvent is formed in the light irradiated area, and an appropriate layer is formed. An image can be formed by removing the non-irradiated areas with an organic solvent.

Furthermore, the image formed in this manner can be easily removed with a dilute solution of hydrazine. This is because the donor cation is reduced to a neutral donor by hydrazine.

Although this imaging material can be used in a wide range of applications,
In particular, it is excellent in application to image formation that requires a fine pattern, such as a negative type resist.

Basic examples showing the characteristics of these materials will be shown below, but the present invention is not limited to these examples.

[Example 1 of the Invention Tetrathiafulvalene (TSF), tetraselenafulvalene (TSeF), tetrathiatetracene (TTT), and perylenetetramethylphenylenediamine were used as donors.

Further, as the photodegradable salt, triphenylsulfonium hexafluorobosphate, 1-rifhenylsulfonium perchlorate, trinoenylsulfonium chloride, ditolyliodonium hexafluorophosphate, cytonyliodonium chloride, and silver chloride were used.

Polystyrene, polyester,
Used epoxy resin.

These were made into a T I-IF solution at the weight ratio shown in Table 1, a film with a thickness of 2 to 10 μm was made, a mask was placed on top of the film, and a 2KW metal halide lamp was placed on top of the film.6.
Irradiation was performed for 10 seconds from a distance of 5 cm. Clear images were formed on the film in both cases.

Below is the margin Example 10 Polystyrene (M W = 20.000. MW/M
A resist solution was prepared by adding TTF, triphenyl, sulfonium, and hexalolophosphate at a weight ratio of 0.52.5% to an 8 wt% ethyl cellosolve acetate solution (rl = 1.3), and then using a spin code method. A resist layer with a thickness of about 0.5 μm was formed on a silicon wafer.

An electron beam with an acceleration voltage of 20 KV is scanned in a pattern to irradiate the resist layer, and then developed with a mixed solvent of methyl isobutyl ketone-2-ethylene and xyethanol (3:2) to form a negative image. did. Irradiation amount 2×1O−
In the case of 6C/Cm, the remaining film thickness was 0.45 μm, and the resolution of the line and space pattern was 0.8 μm, which was extremely good. Moreover, in this pattern, no bridge formation peculiar to negative resists was observed at all.

For comparison, when a similar pattern was formed using polystyrene resist alone, the minimum pattern size obtained with the same dose was 1.2 μm, and there was scum remaining between the patterns.

Example 11 To the same polystyrene-ethyl cellosolve acetate solution as in Example (2), TTF and triphenylsulfonium hexafluorophosphate-1 to 1 were added at a weight ratio of 0.5 to 1, respectively.
．． A resist solution was prepared by adding 2.5%. Using this solution, a resist layer with a thickness of approximately 1.0 μm was formed on a transparent glass wafer, and ultraviolet rays were irradiated using a 600 W Xe-Hcx lamp through a chrome mask containing a pattern with a minimum line width of 1 μm. (Master resist surface distance: 5 μm) After irradiation for about 5 seconds, image processing was performed with methyl isobutyl ketone-2-ethoxyethanol, and a line pattern of approximately 1 μm in diameter was obtained with an extremely high aspect ratio.

[Effects of the Invention] According to the present invention, it is possible to realize an image forming material that can obtain clear images with high resolution.

Claims (3)

[Claims] (1) An image forming material characterized by comprising a compound having electron-donating properties and an organic salt or mono- or inorganic salt that is reduced by light and generates an anion. (2) The compound having electron-donating properties is tetrathiafulvalene, tetraselenafalvalene, tetrathianaphthalin, tetraselenanaphthalene, tetrathiatetracene, tetraselenatetracene, perylene, dithiopyran, tetramethylphenylenediamine, and derivatives thereof. An image forming material according to claim 1. (3) Salts that are characterized by being reduced by light and generating anions are halogen anions (Cl^-, Br^-,
I^-) SbF_6^-, ASF_6^-, PF_6^
The image forming material according to claim 1, which is a tertiary sulfonium salt, iodonium salt, or silver salt of -, ClO_4^-, BF_4^-.