JPS62113134A - Formation of micropattern - Google Patents

Abstract

PURPOSE:To enable slip of pattern position to be eliminated and a submicron pattern high in precision to be formed by coating an electron beam resist with a solution of the salt type complex of polymer polycations and tetracyanoquinodimethane. CONSTITUTION:A thin film is formed on the electron beam resist by coating it with a solution of the salt type complex of polymer cations and tetracyanoquinodimethane having a high electric conductivity of 10<-9>-10<-10>S.cm<-1> in order to prevent accumulation of electrostatic charge generated at the time of electron beam scanning. The complex is soluble in many kinds of solvents, and good in film-forming property at the time of coating the substrate to be treated by the spin coating method, and it can be formed into a uniform electrically conductive film free from any pinhole as thin as 0.05-0.4mum. As the polymer polycations, polyvinylbenzyltriethylammonium, poly-4-vinyl-N-methylpyridinium, and the like can be enumerated.

Description

[Detailed Description of the Invention] [Summary] A fine pattern that eliminates pattern misalignment by coating a conventional electron beam resist with a salt-type complex solution of a polymeric polycation and tetracyanoquinodimethane. How to form a pattern.

[Industrial application field]

The present invention relates to a method for forming fine patterns without positional displacement.

Semiconductor devices, which are the mainstay of information processing equipment as a means of processing large amounts of information at high speed, are increasing in capacity due to high integration, and VLSI, which has a much larger capacity than LSI,
has been put into practical use.

Here, high integration is achieved by miniaturizing unit elements, and the minimum pattern width is reduced to 1 μm or less.

Here, photolithography (photolithography or electron beam lithography) is used to form the fine pattern.

That is, physical methods such as vacuum thin deposition method and sputtering method, and chemical vapor deposition method (Chemical Vapor Deposition method)
A thin film of metal or insulator is formed on the substrate using a chemical method such as ositton (CVO method).
After coating this with resist, selective exposure is performed by irradiating ultraviolet rays through a mask with a pattern drawn on it. When using a positive resist, the light irradiated area becomes soluble in the developer, while when using a negative resist, it is exposed to ultraviolet rays. A resist pattern is created by taking advantage of the property that the irradiated area is insoluble, and a fine pattern is created by performing dry etching such as chemical etching or reactive ion etching on the resist pattern.

However, in the pattern forming method using lt to ultraviolet exposure, the formation of fine patterns is limited to lines with a line width of 1 μm or more due to wavelength limitations, and it is difficult to form fine patterns with a line width smaller than this.

On the other hand, the wavelength of an electron beam varies depending on the accelerating voltage, but is 0.1
Since it is about the size of a human and is more than four orders of magnitude shorter than the wavelength of light, it can be expected to have great resolution, and it is also possible to form patterns with a width of 0.1 μm.

For this reason, electron beam exposure is used instead of conventional ultraviolet exposure to form fine patterns.

However, when electron beam exposure is performed, since electrons have a negative charge, charge is accumulated on the surface of the resist, which causes a problem in that the position of the pattern is shifted.

[Conventional technology]

As mentioned earlier, since the electron beam has a short wavelength, it is possible to draw resist patterns of 1 μm or less, and since the electron beam can be scanned and drawn directly, there is no need for a mask, which reduces the mask manufacturing time and optics. Cost reduction is achieved along with the elimination of physical defects.

However, on the other hand, since electrons have a negative charge, charges are accumulated in the electron beam scanning section (hereinafter simply referred to as the exposure section), and this accumulated charge bleeds, causing a pattern misalignment.

This positional misalignment is caused by the conventional bag width and spacing
Although this is not a problem in the case of m units, it is a problem in the case of so-called sub-micron patterns of 1 μm or less.

However, no effective measures have been taken to date to deal with this problem.

[Problem that the invention seeks to solve]

As described above, when performing electron beam exposure, charge is accumulated in the exposed portion, and the problem is how to solve the positional shift caused by this bleeding.

[Means for solving problems]

The above problem can be solved by implementing a pattern forming method in which an electron beam resist is coated with a salt-type complex solution consisting of a polymeric polycation and tetracyanoquinosimethane.

[Effect]

In the present invention, the conductivity of a salt-type complex consisting of a polymeric polycation and tetracyanoginodimethane (abbreviated as TCNQ) is 10.
= ~10-"S-cm-', and the conductivity of conventionally used resists is 10-16 to 10-"S-c.
Taking advantage of the fact that it has an extremely high value compared to m-', this thin film is coated on top of conventional resist to eliminate the accumulation of charge that occurs during electron beam scanning. .

In other words, the above complex is soluble in various solvents, has good film forming properties when applied onto a substrate to be processed using a spin code method, and can form a uniform film without pinholes. 0.05-0.4 on the resist of
It is applied to a thickness of about μm to make it conductive.

Here, the polymeric polycations include polyvinylhensyltriethylammonium, poly-4-vinyl-N-methylpyridium, polydiallyldimethylammonium, polydiallyldimethylammonium sulfone, poly-N,
Examples include N, N', N'-tetramethylhexamethylene diammonium.

〔Example〕

Polyvinylbenzyltriethylammonium and lithium (Li)-TCNQ salt were separately dissolved in ethanol, each having a volume of 0.04 mol/β.

The two were mixed and stirred for 1 hour at room temperature in a nitrogen (N2) stream to synthesize a polyvinylhensyltriethylammonium-TCNQ salt type complex.

Next, as an example of the present invention, after spin-coding a cross-linked methacrylate resist on a silicon (Si) substrate,
A positive resist layer having a thickness of 1 μm was formed by a haking treatment at 00° C. for 15 minutes.

A 5% by weight cyclohexanone solution of the above complex was applied onto the substrate by a spin-coating method to a thickness of 0.2 μm.
A conductive coating film was formed and dried by baking at 80° C. for 30 minutes.

Next, place the substrate in an electron beam exposure device and apply an acceleration voltage of 20K.
After scanning and drawing a pattern under the conditions of V, exposure amount 3 x 1O-5C/cm2, it was developed for 3 minutes using a mixed solution of cyclohexanone and dimethylformamide in a ratio of 10=1, and then developed with isopropyl alcohol. A resist pattern was created by rinsing for 30 seconds.

In the pattern formed by performing such conductive treatment, no positional shift that occurs when forming using only a conventional resist was observed.

〔Effect of the invention〕

As described above, by carrying out the present invention, there is no charge accumulation during electron beam exposure, so the problem of pattern misalignment is resolved, thereby making it possible to form highly accurate submicron patterns.

Claims (1)

[Claims] A method for forming a fine pattern, characterized by using a salt type complex solution consisting of a polymeric polycation and tetracyanoquinodimethane, coated on an electron beam resist.