Radiation imagery chemistry: process – composition – or product th – Diazo reproduction – process – composition – or product – Composition or product which contains radiation sensitive...
Reexamination Certificate
2002-04-05
2004-02-17
Chu, John S. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Diazo reproduction, process, composition, or product
Composition or product which contains radiation sensitive...
C430S270100, C430S905000
Reexamination Certificate
active
06692884
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a positive photoresist composition for use in ultra-micro-lithography processes, such as the manufacture of ultra LSI (large-scale integrated circuit) and high capacitance micro chips, and in other photo-fabrication processes.
More specifically, the present invention relates to a positive photoresist composition capable of forming a highly precise pattern using the light in the region of far ultraviolet rays including excimer laser rays, in particular the lights of wavelength of 250 nm or lower.
BACKGROUND OF THE INVENTION
The degree of integration of integrated circuits has been heightened more and more in recent years, and the process of ultra-fine pattern comprising line width of half a micrometer or less has been required in the manufacture of semiconductor substrates, such as ultra LSI. For satisfying the necessity, the wavelengths used in the exposure apparatus for photo-lithography have become short waves more and more, and the use of short wavelength excimer laser rays (XeCl, KrF, ArF, etc.) of far ultraviolet rays has been discussed now.
Chemically amplified resists are used for the pattern formation of lithography in the above wavelength region.
In general, chemical amplification series resist compositions can be roughly classified into three kinds of a two component system, a two and a half component system and a three component system. A two component system comprises a combination of a compound which generates an acid by photo-decomposition (hereinafter referred to as a light-acid generating agent) and a binder resin. The binder resin is a resin having a group which is decomposed by the action of an acid and increases the solubility of the resin in an alkali developer (an acid-decomposable group) in the molecule. A two and a half component system comprises a combination of the above two component system and a low molecular weight compound having an acid-decomposable group. A three component system comprises a light-acid generating agent, an alkali-soluble resin and the above-described low molecular weight compound.
The chemical amplification series resist compositions are suitably used in the photoresist for irradiation with ultraviolet and far ultraviolet rays, but it is further necessary to cope with required characteristics on use. For example, when the light of the wavelength of 248 nm of a KrF excimer laser is used as an exposure light source, a resist composition comprising a hydroxystyrene polymer particularly small in light absorption containing an acetal group or a ketal group as a protective group is proposed. Further, similar compositions containing a t-butoxycarbonyloxy group or a p-tetrahydropyranyloxy group as an acid-separable group are proposed.
Although these resist compositions suit the wavelength of 248 nm of a KrF excimer laser, since the absorbance is substantially too large when an ArF excimer laser is used as a light source, the sensitivity is low. Further, there are other problems coming from the absorbance, e.g., deterioration of definition, deterioration of the tolerance of focus and deterioration of pattern profile, therefore, there is much room for improvement.
As the photoresist composition for an ArF light source, a resin having an alicyclic hydrocarbon moiety for the purpose of imparting dry etching resistance is suggested. As such resins, resins obtained by copolymerizing a monomer having a carboxylic acid moiety, such as an acrylic acid and a methacrylic acid, or a monomer having a hydroxyl group or a cyano group in the molecule, with a monomer having an alicyclic hydrocarbon group are proposed.
On the other hand, a method of providing dry etching resistance by using an alicyclic hydrocarbon moiety as a polymer backbone chain is also discussed besides the method of introducing an alicyclic hydrocarbon moiety to the side chain of an acrylate monomer.
Resist materials comprising an alkali-soluble group protected with a structure containing an alicyclic group, and an acid-sensitive compound containing a structural unit capable of making the alkali-soluble group dissociate by acid to thereby bring into alkali-soluble are disclosed in JP-A-9-73173 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”), JP-A-9-90637, and JP-A-10-161313.
Resins comprising such an alicyclic group containing a hydrophilic 5- or 6-membered lactone group introduced for the purpose of improving the affinity for an alkali developing solution and the adhesion to a substrate are disclosed in JP-A-9-90637, JP-A-10-207069, JP-A-10-274852 and JP-A-10-239846.
Problems attributable to resins having an acid-decomposable group still remain unsolved even by the above techniques in the photoresist composition (in particular, a photoresist for far ultraviolet exposure), and there are many points required to be improved, e.g., a further increase of sensitivity, an improvement of definition, and an improvement of the adhesion with a substrate caused by containing an alicyclic hydrocarbon group in the molecule at the same time.
Further, in recent years, with the requirement of becoming minute more and more of semiconductor chips, the design pattern of the semiconductor has reached the region as fine as 0.13 to 0.35 &mgr;m.
However, various characteristics, such as the reduction of development defects and halftone exposure aptitude, cannot be satisfied by the prior techniques.
The halftone exposure aptitude indicates whether side lobe (a phenomenon that the surface of unexposed area becomes weak and comes to be perforated) which is caused when exposure is performed with a half tone phase shift mask is not caused or difficultly caused.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a positive photoresist composition which is improved in development defect in the production of a semiconductor device and also excellent in halftone exposure aptitude.
As a result of eager investigation of the components of positive chemical amplification resist compositions, the present inventors found that the above object of the present invention could be obtained by using an acid-decomposable resin having a specific lactone structure, which led to the present invention.
That is, the above object of the present invention can be achieved by the following means.
(1) A positive photoresist composition comprising:
(A) a compound capable of generating an acid upon irradiation with one of an actinic ray and a radiation, wherein the compound (A) includes:
(A1) a sulfonate compound of a sulfonium; and
(A2) at least one compound of a sulfonate compound of an N-hydroxyimide and a disulfonyldiazomethane compound; and
(B) a resin capable of decomposing by the action of an acid to increase the solubility in an alkali developer, wherein the resin (B) contains a repeating unit having a group represented by at least one of formulae (I-1), (I-2), (I-3) and (I-4):
wherein R
1
, R
2
, R
3
, R
4
and R
5
, which may be the same or different, each represents a hydrogen atom, an alkyl group, a cycloalkyl group, or an alkenyl group; and two of R
1
, R
2
, R
3
, R
4
and R
5
may be bonded to form a ring.
(2) The positive photoresist composition as described in the item (1), wherein the resin (B) further contains a repeating unit having an alkali-soluble group protected by at least one of groups containing an alicyclic hydrocarbon structure, which are represented by formula (pI), (pII), (pIII), (pIV), (pV) or (pVI):
wherein R
11
represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a sec-butyl group; Z represents an atomic group necessary to form an alicyclic hydrocarbon group together with the carbon atom; R
12
, R
13
, R
14
, R
15
and R
16
each represents a straight chain or branched alkyl group having from 1 to 4 carbon atoms, or an alicyclic hydrocarbon group, and at least one of R
12
, R
13
and R
14
, or at least one of R
15
and R
16
represents an alicyclic hydrocarbon group; R
17
, R
18
, R
19
, R
20
and R
Aoai Toshiaki
Fujimori Toru
Kodama Kunihiko
Sato Kenichiro
LandOfFree
Positive photoresist composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Positive photoresist composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Positive photoresist composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3284536