Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
2002-03-11
2004-08-17
Ashton, Rosemary (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S905000, C430S914000, C430S921000, C522S031000
Reexamination Certificate
active
06777160
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a positive-working resit composition used in an ultramicrolithography process or another photofabrication process for the production of a very large scale integrated circuit (i.e., an ultra-LSD) or a high capacity microchip.
BACKGROUND OF THE INVENTION
In recent years, integrated circuits have been progressively increased in their integration degree, and therefore processing of ultrafine patterns having a line width of a half micron or less has become necessary in the production of semiconductor substrates for very large scale integrated circuits. For fulfilling this necessity, the wavelength of light used in exposure devices employed for photolithography has become progressively shorter, and now, of the far ultraviolet rays, the use of eximer laser light having a short wavelength (such as XeCl, KrF or ArF) has been studied.
Used in the pattern formation of lithography in this wavelength region are chemical amplification system resists.
In general, the chemical amplification system resists can be roughly divided into three classes, commonly called as 2-component system resists, 2.5-component system resists and 3-component system resists. In the 2-component system resist, a compound generating an acid by photolysis (hereinafter referred to as a photoacid generating agent) is combined with a binder resin. The binder resin is a resin having a group which is decomposable by the action of an acid to enhance the solubility of the resin in an alkali developing solution (also referred to as an acid-decomposable group) in its molecule. The 2.5-component system resin contains a low molecular weight compound further having an acid-decomposable group in addition to such a 2-component system resin. The 3-component system resin contains the photoacid generating agent, an alkali-soluble resin and the above-described low molecular weight compound.
The above-described chemical amplification system resists are suitable for photoresists for ultraviolet or far ultraviolet ray irradiation. However, they are further required to comply with desired characteristics for use.
Further, resins are proposed into which alicyclic hydrocarbon moieties are introduced for imparting the resistance to dry etching. However, the systems become extremely hydrophobic as an adverse effect of the introduction of the alicyclic hydrocarbon moieties. The phenomenon is therefore observed that the development with aqueous solutions of tetramethylammonium hydroxide (hereinafter referred to as TMAH) which have hitherto been widely used as resist developing solutions becomes difficult, or that resists are separated from substrates during the development.
For complying with such hydrophobization of resists, a measure of mixing organic solvents such as isopropyl alcohol with the developing solutions has been studied, and results have been observed although not quite satisfactorily. However, there is fear of swelling of resist films, and the process becomes complicated. It is therefore not necessarily said that problems have been solved. As approaches to the improvement of resists, there have been taken many measures for compensating for various hydrophobic alicyclic hydrocarbon moieties by the introduction of hydrophilic groups.
Japanese Patent Application (Laid Open) No. 10739/1998 discloses energy-sensitive resist materials containing polymers obtained by polymerization of monomers having alicyclic structures such as norbornene rings on their main chains, maleic anhydride and monomers having carboxylic groups. Japanese Patent Application (Laid Open) No. 111569/1998 discloses radiation-sensitive resin compositions containing resins having alicyclic skeletons on their main chains and radiation-sensitive acid generating agents.
Japanese Patent Application (Laid Open) No. 130340/1998 discloses chemical amplification type resists containing terpolymers having specific repeating structural units having norbornene structures on their main chains.
Japanese Patent Application (Laid Open) No. 305444/1999 discloses resins containing repeating structural units having adamantane structures on their side chains, and maleic anhydride as repeating structural units.
EP 1048983A1 discloses compositions containing resins having repeating units composed of specific acid-decomposable group containing norbornene, repeating units composed of anhydrides and repeating units having alicyclic groups, for improving storage stability, transparency, dry etching properties, sensitivity, resolution and pattern shape.
Japanese Patent Application (Laid Open) No. 501909/1999 proposes compounds having imide or methide acids, which are strong acids, as anions, for improving the solubility of initiators, hardeners or salts used as catalysts in organic solvents and the catalytic activity thereof.
Further, Research Disclosure 437031 proposes the probability of applying compounds generating imide or methide acids by photolysis to resist compositions.
In Japanese Patent Application (Laid Open) No. 73173/1997, resist materials are described in which acid-sensitive compounds containing alkali-soluble groups protected with alicyclic group-containing structures and structural units which are allowed to become alkali-soluble by releasing the alkali-soluble groups with acids are used.
However, the conventional positive-working resist compositions have not given satisfactory results in evaluation of the resolving power and the exposure margin in micro-photofabrication using far ultraviolet rays, particularly ArF eximer laser beams.
SUMMARY OF THE INVENTION
An object of the present invention to provide a positive-working composition which is excellent in the resolving power and the exposure margin, and can be suitably used for microphotofabrication using far ultraviolet rays, particularly ArF eximer laser beams.
The present inventors have intensively studied materials constituting positive-working chemical amplification system resist compositions. As a result, the present inventors have discovered that the object of the present invention is attained by using specific acid-decomposable resins and specific photoacid generating agents, thus completing the invention.
That is to say, the above-described object is attained by the following constitution:
(1) A positive-working resist composition comprising (A) a resin which has an aliphatic cyclic hydrocarbon group and enhances in the dissolution rate in an alkaline developing solution by an action of an acid, and (B) a compound generating an acid by irradiation of actinic ray or radiation, wherein the resin of (A) is a resin having repeating structural units represented by formula (I), repeating structural units represented by formula (II) and repeating structural units represented by formula (III), and the resin of (B) is a compound represented by formula (Ia) or (IIb):
wherein R
11
′ and R
12
′ each independently represents a hydrogen atom, a cyano group, a halogen atom or an alkyl group; and Z′ represents an atomic group for forming an alicyclic structure which contains two combined carbon atoms (C—C) and may have a substituent group.
wherein Z
2
represents —O— or —N(R
41
)—, wherein R
41
represents a hydrogen atom, a hydroxyl group, an alkyl group, a haloalkyl group or —OSO
2
—R
42
. R
42
represents an alkyl group, a haloalkyl group, a cycloalkyl group or a camphor residue:
wherein R
91
represents a hydrogen atom, a lower alkyl group, a halogen atom or —CN; X
5
represents —O—, —S—, —NR
93
— or NR
93
SO
2
—, wherein R
93
represents a hydrogen atom or a chain or cyclic alkyl group; B represents a single bond or a connecting group, and R
92
represents a hydrogen atom, a chain or cyclic alkyl group, an alkoxyl group, a hydroxyl group, a carboxyl group, a cyano group, —COOR
94
or a group represented by any one of the following formulas (IV) to (X), wherein R
94
represents a hydrogen atom or a chain or cyclic alkyl group:
—N
+
(R
95
)(R
96
)(R
97
)·X
−
(VIII)
—R
98
—A
50
—R
99
(IX)
—SO
3
R
100
(X
Kodama Kunihiko
Sato Kenichiro
Ashton Rosemary
Fuji Photo Film Co. , Ltd.
Sughrue & Mion, PLLC
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