JPH0521227B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to energy-sensitive polymeric materials, particularly to polymeric materials that are sensitive to electron beams, X-rays, ion beams, deep ultraviolet light, or ultraviolet light. (Prior art and its problems) In recent years, improvements in the element characteristics and functionality of semiconductor devices have been extremely remarkable, but as the fields of use thereof have expanded, further improvements in performance have been required. Although this can be achieved to some extent by improving the circuit and increasing the chip size, it is known that the most effective method is to miniaturize the elements.
Traditionally, such processing has used photolithography technology, which forms a resist pattern by irradiating ultraviolet light, but since there is a limit to processing accuracy on the order of the wavelength of light, deep ultraviolet rays, X-rays, electron beams, etc. have been used. Microfabrication using microfabrication has become important. As a result of research on these new exposure technologies,
It has become clear that even with these new technologies, it is difficult to process dimensions of 1 μm or less due to scattering phenomena and variations in the development process, unless the resist film is thinned and exposed in a uniform state. . However, in reality, complex steps are gradually formed on the substrate according to the device manufacturing process, so making the resist thin enough to sufficiently improve resolution is difficult because of the way the resist wraps around the steps. It was possible. Therefore, a three-layer resist process was proposed, as described by Mr. G. M. Moran et al. of Bell Laboratories in the United States in a paper from Journal of Bakyoum Science and Technology, Vol. 16, p. 1620. It was done. Although this method is extremely effective, the process is complicated, and an attempt was made to create two layers as shown in Japanese Patent Application No. 57-090639. In the invention, a phenyl group is introduced to improve the glass transition point of the silicone resin, but
It is difficult to achieve a glass transition point of 150°C or higher, and some processes, such as the lift-off process for refractory metals and other high-melting point metals, have drawbacks that make them difficult to use. (Effects of the Invention) The present invention is a silicone resin resist that can be used in a two-layer resist process, and has a glass transition point of 150.
The object of the present invention is to provide a polymer resist and process that can be used in high-temperature processes that reach temperatures higher than ℃. (Summary of the invention) The present invention includes the following: (), (), () and ()
Structural unit represented by the general formula An energy ray-sensitive polymer resist consisting of the formula, where X is a halogen,

[Formula] -O-CH ₂ CH=CHR, -NH-CH ₂ CH=CHR,

[expression] or

[Formula], R, R', R'' are hydrogen or an alkyl group, n is a value of 1 to 5, and the structural unit ()
When a plurality of (-CH ₂
The ratio of the total number of structural units () and () to the total number of structural units is 80% or less, the ratio of the number of () to structural units () is 10 to 30%, and the total number of structural units () The energy-sensitive polymer resist is characterized in that the ratio to the number of structural units is 5 to 10%. It was already known that introducing phenyl groups into silicone resins improves the glass transition point, but we discovered that introducing naphthyl groups can improve the glass transition point more efficiently.
A resist material that is easy to use in a two-layer resist process etc. can be provided. (Example) A copolymer of methyl phenyl silicone and methyl, and a copolymer of naphthyl silicone and dimethyl silicone, with a degree of polymerization of 500 to 2500. The phenyl group of the silicone resin is chloromethylated with chloromethyl methyl ether, and then the resist is made into an isoamyl acetate solution. It was made into a liquid. Silicone is synthesized by hydrolyzing the corresponding chlorosilane compound in ethyl ether and polymerizing it with ammonium hydroxide. 1st
FIGS. 4 to 4 are drawings for explaining the case where the resist of the present invention is used in a gate wiring forming process, which is one process of manufacturing a semiconductor device, and are sequential views showing schematic cross sections of the semiconductor device. 11 is a silicon substrate, 12 is a silicon oxide film for isolation, and 13 is a gate oxide film.
First, a novolac resin 14 is spin-coated to a thickness of 1 to 5 .mu.m as a base organic film for surface flattening. Reference numeral 15 is an example of the resist of the present invention, which is obtained by spin-coating the above solution to a film thickness of 0.2 μm to 1 μm. (FIG. 1) Thereafter, for example, an electron beam with an acceleration voltage of 20 KV is selectively irradiated at a dose of about 5×10 ⁻⁶ clones/cm ² and developed with isoamyl acetate to obtain a negative pattern. Next, the underlying organic film is anisotropically processed by reactive sputter etching in an oxygen atmosphere of approximately 0.1 Torr to 0.01 Torr. (Figure 2)
It was found that the oxygen plasma resistance of the dimethyl and methylnaphthyl silicone film 15, in which the phenyl group was chloromethylated, was about 10 times that of the novolac resin, and showed sufficient resistance as an etching mask. Thereafter, a film 31 of a high melting point metal such as molybdenum is deposited by vacuum evaporation. The resist of the present invention has high heat resistance, does not change in quality even when a high melting point metal is vapor deposited, and acts as a protective material for the underlying organic film. (FIG. 3) Then, when immersed in a heated Ascent solution, the underlying organic film is dissolved and a desired gate wiring pattern 41 is left behind through a so-called lift-off process.
Unnecessary parts of the high melting point metal and resist are removed. As detailed above, a high-resolution negative resist has a silicone structure that improves oxygen plasma resistance, a naphthalene ring that increases the glass transition point, and a benzene ring that improves sensitivity through chloromethylation and adjusts exposure characteristics. Although it was obtained,
The above examples are illustrative, and the improvement in the glass transition point due to the naphthalene group can be obtained for each composition ratio, so it is possible to change the substituents of each component for the purpose of adjusting plasma resistance, sensitivity, and resolution. is clear. In the present invention, the structural units (), (), (),
The reason why the sum of the numbers in parentheses is set to 50 or more is to form a uniform film when applied to a substrate. Setting the proportion of structural units () to 5 to 10% is
This is because, although up to several tens of percent, the higher the glass transition temperature, the higher the glass transition temperature, but if it is too high, the sensitivity will decrease. The ratio of () to structural unit () is 10 to 30
The reason why it is set to % is that the lower limit wants to ensure sensitivity, and the upper limit wants to reduce dispersion. If only the structural units (), (), and () are used, the adhesion and coating properties to the substrate will be poor, so the ratio of () + () to the total structural units should be up to 80%, and () should be up to 80%.
It is kept at 10%, and the rest is made up of structural units (). Also, halogen as X,

[Formula] -O-CH ₂ CH=CHR, -NH-CH ₂ CH=CHR When using electron beam,
It is sensitive to radiation, ion boom, and deep ultraviolet light, but

【formula】

[Formula] is sensitive to ultraviolet light. In addition, by selecting the substituents of the structural unit (), energy rays other than electron beams, such as X
It is also clear that improvements are possible for use with UV light, deep UV light, and UV light. (Effects of the invention) With the development of the high glass transition point and high oxygen plasma resistance resist of the present invention, the two-layer resist process, etc. has become extremely simple, and submicron exposure, which is essential for VLSI manufacturing, has become a reality. .

[Brief explanation of the drawing]

Figures 1 to 4 show the high glass transition temperature of the present invention;
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram sequentially showing schematic cross-sections of a semiconductor device in the main steps of manufacturing a semiconductor device for explaining the effectiveness of a plasma-resistant energy ray-sensitive polymer resist. The numbers in the figure indicate the following. , 11: semiconductor substrate, 12: oxide film for element isolation, 13: gate oxide film, 14: underlying organic film for planarization, 15: high glass transition point/plasma resistant resist film of the present invention,
31: High melting point metal, 41: Gate wiring metal film patterned by lift-off process.

Claims (1)

[Claims] 1 Structural units represented by the following general formulas (), (), () and () An energy ray-sensitive polymer resist consisting of the formula, where X is a halogen,
[Formula] -O-CH ₂ CH=CHR, -NH-CH ₂ CH=CHR,
[Formula] or [Formula], R, R', R'' are hydrogen or an alkyl group, n is a value of 1 to 5, and the structural unit ()
When a plurality of (-CH ₂
The ratio of the total number of structural units () and () to the total number of structural units is 80% or less, the ratio of the number of () to structural units () is 10 to 30%, and the total number of structural units () An energy-sensitive polymer resist characterized in that the ratio of structural units to the number of structural units is 5 to 10%.