JPS6365142B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a novel developer for rubber-based photoresists, particularly an excellent developer capable of developing sharp patterns with fine line widths without swelling the photocured areas of rubber-based photoresists during development. It is related to developer.

Microfabrication in the production of transistors, ICs, LSIs, etc. is performed by photolithography using photoresists, especially rubber-based photoresists.

Photolithography involves forming a photoresist layer on a silicon wafer that has an oxide film on its surface, exposing that layer to light through a required mask pattern, developing it, and then rinsing it to form the desired resist pattern. is formed.

Conventionally, in such photolithography, xylene, an aliphatic hydrocarbon solvent, or a combination thereof is used as a developer, and n-butyl acetate is generally used as a rinsing solution. However, when xylene, aliphatic hydrocarbon solvents, or a mixture of these is used as a developer, the unexposed areas are completely dissolved and removed, but the photoresist areas (resist pattern) that have been hardened by exposure swell. Therefore, it has been difficult to obtain a highly accurate resist pattern due to bridging, wrinkles, drooping, or jaggedness, especially in extremely fine resist pattern portions. In order to suppress this swelling phenomenon, a so-called rinsing treatment with acetic acid n-butyl ester is usually performed following the development treatment, but a satisfactory effect has not been obtained.

In particular, technological progress has been remarkable in recent years, and the degree of integration of semiconductors has increased, for example, to 16 kilobits, 64 kilobits, and even 256 kilobits.
It goes without saying that high resolution of resist patterns is required, but fine dimensional accuracy is also required.
It has become necessary to have a minimum line width resolution of around 1.5 μm.

As described above, based on the fact that conventional photoresist manufacturing techniques, especially methods using conventional developers that cannot suppress the swelling phenomenon during development, are no longer able to meet the demands of the semiconductor industry in recent years, the present inventors In order to develop a high-precision photoresist manufacturing technology, they conducted various studies in particular on developing solutions for rubber-based photoresists, and as a result, they have effectively overcome the drawbacks of conventional developing solutions for rubber-based photoresists.
We have found a solvent that provides the desired photoresist pattern with excellent accuracy.

That is, the present invention provides aliphatic hydrocarbons having 5 to 12 carbon atoms and 5 to 12 carbon atoms based on the aliphatic hydrocarbons.
Provided is a rubber-based photoresist developer comprising 40% by volume of a polyhydric alcohol-based organic solvent.

The main component of the developer of the present invention has 5 carbon atoms.
~12 aliphatic hydrocarbons include n-pentane, n-
Hexane, n-heptane, n-octane, n-nonane, n-decane, n-undecane, n-dodecane and their isomers, which may be used alone or in combination of two or more types. I can do it.

Further, in the present invention, the polyhydric alcohol-based organic solvent which is another component to be mixed with the above aliphatic hydrocarbon is a mono-lower alkyl ether of a hydroxyl compound such as ethylene glycol, ethylene glycol monoacetate, diethylene glycol or diethylene glycol monoacetate. Typical examples of monophenyl ethers include monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, and monophenyl ether. These can also be used alone or in combination of two or more.

The developer of the present invention is a mixed solvent consisting of the above aliphatic hydrocarbon and the above polyhydric alcohol organic solvent in an amount ranging from 5 to 40% by volume, and is used as a developer for rubber photoresists. When this is done, the swelling phenomenon of the photoresist portion is effectively suppressed, and therefore, there are no various inconvenient phenomena associated with swelling, and a resist pattern with excellent precision can be easily obtained.

If the amount of the polyhydric alcohol-based organic solvent mixed with the aliphatic hydrocarbon is less than 5% by volume, it will cause swelling of the resist pattern like a conventional developer, and the object of the present invention cannot be achieved. If it exceeds 60% by volume, the developing power will decrease and it will not function as a developer. The preferred mixing ratio of polyhydric alcohol organic solvent to aliphatic hydrocarbon is 10 to 35
It is capacity %.

Further, when the aliphatic hydrocarbon has a carbon number other than 5 to 12, it is disadvantageous because a mixture of polyhydric alcohol-based organic solvents does not have excellent developing ability as a developer for rubber-based photoresists.

The developer of the present invention can be applied to known rubber photoresists. Examples of such rubber-based photoresists include 1,2-polybutadiene, 1,2-polybutadiene cyclized products, cis-1,
4-polybutadiene cyclized product, trans-1,4-
cyclized products of polymers containing butadiene as a constituent component, such as polybutadiene cyclized products, styrene-butadiene copolymer cyclized products, and derivatives thereof, natural rubber cyclized products, cis-1,4 polyisoprene cyclized products, trans-1, 4-polyisoprene cyclized product,
Examples include photoresists whose main components are polymers containing isoprene as one component, such as cyclized styrene-isoprene copolymers, and cyclized products of derivatives thereof, and which are blended with a photocrosslinking agent.

In particular, preferred polymeric photoresists to which the present invention is applied include those having a number average molecular weight of 30,000 to 200,000;
A photoresist using the above-mentioned cyclized product with a degree of cyclization of 30 to 85%, and optimally a number average molecular weight of 50,000 to 15
10,000, a cyclized product of cis-1,4-polybutadiene, a cyclized product of trans-1,4-polybutadiene, a cyclized product of trans-1,4-polyisoprene, or a cyclized product of cis-1,4-polyisoprene with a degree of cyclization of 40 to 75%. These include photoresists that use chemical compounds. Among them, trans-1,4-polyisoprene cyclized product or cis-1,
Suitable for photoresists using cyclized 4-polyisoprene. Such photoresists include OMR83 (product name, manufactured by Tokyo Ohka Kogyo Co., Ltd.);
There are commercially available products such as KMR747 (product name, manufactured by Eastman Kodak Co.) and Waycoat Type 3 (product name, manufactured by Philippe Hunt Chemical Company).

Note that the developer used in the present invention contains a surfactant,
For example, the developability, particularly the solubility, can be improved by adding a fatty acid ester nonionic surfactant.

When developed using the rubber-based photoresist developer of the present invention, bridging of the resist pattern,
No wrinkles, droop or jaggedness occurs, and it is extremely advantageous for forming fine patterns of around 1.5 μm. Furthermore, since the developer of the present invention has a large tolerance in developing rubber-based photoresists, even if the development time is excessive, the resist pattern will not be affected at all, and it is also excellent in practical use.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Rubber photoresist OMR83 (product name,
(manufactured by Tokyo Ohka Kogyo Co., Ltd.) was coated with a spinner and placed in an oven kept at 80°C for 20 minutes to form a photoresist layer with a thickness of 800 nm. next,
A chrome resolution test chart was placed on top of it, and contact exposure was carried out for 2 seconds in a nitrogen atmosphere using a 200W ultra-high pressure mercury lamp. Subsequently, it was immersed in a developer consisting of 70% by volume of n-heptane and 30% by volume of ethylene glycol monoethyl ether acetate, and developed for 1 minute. The resulting resist pattern did not show any fine wrinkles, sag, or creases, and a sharp pattern with a line width of 1.5 μm was obtained, and there was no need for rinsing.

For reference, when the resist pattern was subsequently rinsed by immersion in acetic acid n-butyl ester for 1 minute, no particular change was observed in the resist pattern.

Example 2 70% by volume of n-hexane, 10% by volume of ethylene glycol monomethyl ether and 20% by volume of ethylene glycol monomethyl ether acetate as a developer
A resist pattern was formed in the same manner as in Example 1 except that a mixed solution of % by volume was used. As a result, as in Example 1, no swelling phenomenon occurred in the resist pattern, and a pattern with a minimum line width of 1.5 μm could be reproduced faithfully to the test chart.

Example 3 A mixture of saturated aliphatic hydrocarbons having 8 to 11 carbon atoms (trade name: Isopar G, manufactured by Etsu Chemical Co., Ltd.) 80% by volume, 10% by volume of ethylene glycol monoethyl ether, and ethylene glycol monoethyl ether acetate Patterning was carried out in the same manner as in Example 1 except that a 10% by volume mixed developer was used. There was no swelling in the resist pattern, and a minimum line width of 1.5 μm could be resolved. Furthermore, when the condition of the resist pattern was observed after being immersed in a developer for 3 minutes, there was no disturbance of the resist pattern due to excessive development. From this, it can be seen that the present developer has a wide permissible range of development conditions and is extremely desirable from a practical standpoint.

Comparative Example 1 Using a conventionally used developer consisting of a mixture of 70% by volume of n-heptane and 30% by volume of xylene,
Patterning was carried out in the same manner as in Example 1, followed by rinsing for 1 minute with acetic acid n-butyl ester. In the portions of the resulting resist pattern with a line width smaller than 4 μm, a fine grain was applied to the edges of the resist. Along with the countless numbers of me appearing, I could also see the resist slipping and twisting. The minimum line width that can be practically used with this developer is 4 μm, and it was confirmed that a pattern with a line width smaller than this cannot be formed.

Further, when the rinsing treatment was not performed, the resist swelled so much that it was not possible to form fine lines of 6 μm or less.

Comparative Example 2 After development was carried out in the same manner as in Comparative Example 1, excessive development for 1 minute was repeated three times, and as the times increased, the swelling of the resist pattern became more severe, and even after rinsing, It became impossible to resolve a line width of 4 μm.

Claims (1)

[Scope of Claims] 1. A rubber photoresist developer comprising an aliphatic hydrocarbon having 5 to 12 carbon atoms and a polyhydric alcohol organic solvent in an amount of 5 to 40% by volume based on the aliphatic hydrocarbon. 2. Claim 1, wherein the polyhydric alcohol organic solvent is ethylene glycol, ethylene glycol monoacetate, diethylene glycol, or monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, or monophenyl ether of diethylene glycol monoacetate. developer solution.