KR19980015739A - Solubility inhibitor for chemically amplified resist - Google Patents

Abstract

The present invention discloses a chemically amplified resist dissolution inhibitor represented by Chemical Formula (1).

[Chemical Formula 1]

Here, R is selected from C ₁ to C ₁₀ hydrocarbons or C _{6 to} C ₁₂ aromatic compounds, and R ₁ is selected from a tert-butyl group or a tetrahydropyranyl group. The dissolution inhibitor of the present invention is a novel malonate derivative compound, and when it is used, a resist composition having excellent sensitivity and contrast can be obtained.

Description

Solubility inhibitor for chemically amplified resist

The present invention relates to a dissolution inhibitor for chemically amplified resists, and more particularly, to a novel dissolution inhibitor capable of obtaining a resist having an improved contrast and sensitivity by maximizing a difference in solubility before and after exposure.

As the degree of integration of semiconductor chips increases, it is required to form sub-micron-order fine patterns in a lithography process. Particularly in lithography processes for the fabrication of ultra-high integration circuits, higher resolution is required in a short wavelength (DUV region). Accordingly, a lithography technique using a deep-UV (deep-UV: 254 nm) shorter wavelength than the conventional g-line (436 nm) and i-line (365 nm) a new concept of chemically amplified resist (CAR) has been introduced.

A chemically amplified resist is a material which can form a pattern while H ⁺ (proton) generated by exposure is used as a catalyst and the diffusion and decomposition reaction of H ⁺ occurs in a chain and maintains transparency. Generally, a chemically amplified resist is composed of a base resin and a photoacid generator (PAG) having a dissolution inhibiting group introduced to suppress solubility. In addition, a dissolution inhibitor may be further added to control the dissolution rate of the resist. Such a dissolution inhibitor is a very important factor in a resist composition because it serves to reinforce the function of the resist by maximizing the dissolution rate difference between the exposed and unexposed portions of the base resin.

Thus, the present inventors have come to synthesize a dissolution inhibitor capable of maximizing the dissolution rate difference between the exposed portion and the unexposed portion of the base resin.

SUMMARY OF THE INVENTION The present invention provides a chemically amplified resist dissolution inhibitor which is improved in contrast and sensitivity by significantly reducing the dissolution rate in the unexposed portion and increasing the dissolution rate in the exposed portion.

In order to achieve the above object, the present invention provides a chemically amplified resist dissolution inhibitor represented by Chemical Formula (1).

Here, R is selected from C ₁ to C ₁₀ hydrocarbons or C _{6 to} C ₁₂ aromatic compounds, and R ₁ is selected from a tert-butyl group or a tetrahydropyranyl group. Wherein R is a cyclohexyl group, a bismethylcyclohexyl group, a phthalic group, an isophthalic group, a terephthalic group, a 1,2-, 1,3- and 1,4-dialkylcyclohexyl group, a 1,3,5- Trialkylcyclohexyl groups, and 1,2-, 1,3- and 1,4-cyclohexanedicarboxyl groups. Among them, 1,4-bis (di-tert-butylmalonylmethyl) cyclohexane, 1,4-bis (di-tert- butylmalonyl) cyclohexane, 1,4- Carbonyl) benzene and 1,4-bis (di-tert-butylmalonylcarbonyl) cyclohexane are preferable. The synthesis process of these compounds will be described with reference to Reaction 1.

To obtain 1,4-bis (di-tert-butylmalonylmethyl) cyclohexane (II), 1,4-bis (bromomethyl) cyclohexane is added dropwise to di-tert-butyl malonate and sodium hydride . Followed by reaction at about 65 to 75 ° C for at least about 12 hours and then work-up.

Except that 1,4-bis (di-tert-butylmalonyl) cyclohexane (III) was obtained by using 1,4-dibromocyclohexane instead of 1,4-bis (bromomethyl) cyclohexane. 4-bis (di-tert-butylmalonylmethyl) cyclohexane (II) (Scheme 2).

The 1,4-bis (di-tert-butylmalonylcarbonyl) benzene (IV) is obtained by reacting terephthalic chloride and di-tert-butylmalonate in the presence of a base such as potassium carbonate, (Scheme 3).

Except that 1,4-bis (di-tert-butylmalonylcarbonyl) cyclohexane (V) used 1,4-cyclohexanedicarboxyloyl chloride instead of terephthalic chloride Can be obtained by a method similar to that of 1,4-bis (di-tert-butylmalonylcarbonyl) benzene (IV) (Scheme 4).

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not necessarily limited thereto.

[Example 1]

Synthesis of 1,4-bis (di-tert-butylmalonylmethyl) cyclohexane (II)

2.4 g (0.1 mol) of NaH, 200 ml of THF and 22 g (0.1 mol) of di-tert-butyl malonate were placed in a 500 ml round bottom flask and stirred for about 2 hours. Thereafter, 13.5 g (0.05 mol) of 1,4-bis (bromomethyl) cyclohexane was added dropwise, and the mixture was reacted at 65 to 75 ° C for about 12 hours.

When the reaction was complete, the solvent was removed and the reaction mixture was poured into an excess of water. The mixture was extracted with diethyl ether, and the obtained organic layer was dried with magnesium sulfate and filtered to remove the solvent. The resulting mixture was purified by column chromatography, and then recrystallized from a mixed solvent of methylene chloride and hexane to obtain a product in a yield of about 75%.

[Example 2]

Synthesis of 1,4-bis (di-tert-butylmalonyl) cyclohexane (III)

The procedure of Example 1 was repeated except that 1,4-dibromocyclohexane was used instead of 1,4-bis (bromomethyl) cyclohexane.

[Example 3]

Synthesis of 1,4-bis (di-tert-butylmalonylcarbonyl) benzene (IV)

14 g (0.1 mol) of potassium carbonate and 200 ml of acetonitrile were added to 22 g (0.1 mol) of di-tert-butylmalonate, and then 10 g (0.05 mol) of terephthalic chloride was added. The reaction mixture was stirred at 65 to 80 DEG C for about 12 hours.

When the reaction is complete, the solvent is removed and the reaction mixture is poured into an excess of water. The mixture was extracted with diethyl ether, and the obtained organic layer was dried with magnesium sulfate and filtered. After the solvent was removed, the impurities were firstly removed by column chromatography, and recrystallization was performed using a mixed solvent of hexane and methylene chloride. The product was obtained in a yield of about 83%.

[Example 4]

Synthesis of 1,4-bis (di-tert-butylmalonylcarbonyl) cyclohexane (V)

The procedure of Example 3 was repeated except that 1,4-cyclohexane-dicarboxyloyl chloride was used instead of terephthalic chloride.

A resist composition containing the dissolution inhibitor obtained according to the above Example was prepared. The silicon substrate was treated with hexamethyldisilazane, and then the obtained resist composition was applied.

The resultant was baked, then exposed and developed to form a resist.

The dissolution inhibitor of the present invention is a novel malonate derivative compound, and when it is used, a resist composition having excellent sensitivity and contrast can be obtained.

Claims (4)

A dissolution inhibitor for chemically amplified resist of Chemical Formula (1). [Chemical Formula 1] Here, R is selected from C ₁ to C ₁₀ hydrocarbons or C _{6 to} C ₁₂ aromatic compounds, and R ₁ is selected from a tert-butyl group or a tetrahydropyranyl group. The method according to claim 1, Wherein the R is selected from a cyclohexyl group and a bismethylcyclohexyl group. The method according to claim 1, An isophthalic group, and a terephthalic group, wherein the dissolution inhibitor for chemically amplified resist is a compound represented by the following formula (1). The method according to claim 1, 1,2-, 1,3- and 1,4-dialkylcyclohexyl groups, 1,3,5-trialkylcyclohexyl groups and 1,2-, 1,3- and 1,4-cyclohexanedicarboxylic groups Wherein the dissolution inhibitor for chemically amplified resist is selected from the group consisting of: