Polymer with a pericyclic protective group and resist...

Details Polymer with a pericyclic protective group and resist... Polymer with a pericyclic protective group and resist...

2000-02-28

2003-03-25

Ashton, Rosemary (Department: 1752)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S272000, C526S281000, C430S270100, C430S905000

Reexamination Certificate

active

06538086

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a polymer with at least one pericyclic protective group, and more particularly to a resist composition containing the polymer.
2. Description of the Prior Art
Nowadays, thin film coating technique plays a very important role in chemical engineering technology. A resin suitable for thin film coating should meet the requirements of having good film properties and good adherence to substrates. Therefore, the glass transition temperature of such resin should not be too high. To be considered for application to IC photoresists (resists), a suitable resin should further have other properties such as high etch and heat resistance, properties which are frequently achieved by molecular design.
With increasing integration of semiconductor devices, there is a heightened need to form finer patterns in photolithography processes. A photolithography technology has been proposed which utilizes an ArF excimer laser as a source to generate radiation having a wavelength of 193 nm for producing devices beyond the 1 giga capacity. This technology is intended to replace conventional KrF excimer laser which generates radiation having a wavelength of 248 nm.
A chemically amplified resist composition is a well-known resist composition that is suitable for use in the 193 nm photolithography. The photoresist solution includes a protected resin, a photoacid generator, and a solvent. The so-called protected resin is a resin that is protected by an acid-labile protective group. The resin will be converted into alkali-soluble when the acid-labile protective group is decomposed. When a positive chemically amplified resist composition applied on a substrate is exposed to light, the photoacid generator will generate acid, and the acid will decompose the acid-labile protective group in the resin, thus making the resinsoluble in an alkali developer.
Ito et al. in U.S. Pat. No. 4,491,628 discloses a resist composition in which the resin is protected by t-butyl esters of carboxylic acid. The examples of such protected resins include poly(tert-butyl p-vinylbenzoate) and poly(tert-butyl methacrylate). However, such a resist composition has an insufficient etch resistance and resolution. Moreover, post exposure baking (PEB) should be conducted at a high temperature, so that the integrated circuits are easily degraded, and problems such as proximity effect (isoline and denseline bias) and edge roughness are thus induced.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a novel polymer that exhibits strong etch resistance.
Another object of the present invention is to provide a novel polymer that has the required properties for use in chemically amplified resist for use with ArF laser.
A further object of the present invention is to provide a photoresist composition comprising the novel polymer, which can be post exposure baked at a lower temperature. Thus, problems of the proximity and edge roughness can be solved.
To achieve the above objects, the present invention provides a polymer containing at least one pericyclic protective group G having a formula selected from the group consisting of:
wherein
R
1
is selected from the group consisting of linear or branched alkyl, alkenyl, alkylaryl, arylalkyl having from 1 to 10 carbon atoms, cyclic alkyl having from 3 to 15 carbon atoms, alkoxyl having from 1 to 10 carbon atoms, and
R
2
, R
3
, R
4
, and R
5
can be the same or different and are independently selected from the group consisting of hydrogen, linear or branched alkyl, alkenyl, alkylaryl, arylalkyl having from 1 to 10 carbon atoms, cyclic alkyl having from 3 to 15 carbon atoms, alkoxyl having from 1 to 10 carbon atoms, and
wherein R
11
is selected from the group consisting of hydrogen, linear or branched alkyl, alkenyl, alkylaryl, arylalkyl having from 1 to 10 carbon atoms, cyclic alkyl having from 3 to 15 carbon atoms, alkoxyl having from 1 to 10 carbon atoms, arid R
12
is an alkylene group having from 1 to 10 carbon atoms;
X
1
and X
2
can be the same or different and are independently selected from the group consisting of a halogen, hydroxy, C
1-15
alkoxy, NH
2
, NHR
61
, NR
61
R
62
, SH, SR
63
, —(C═O)H, —(C═O)OH, —(O═O)R
64
, —(C═O)OR
65
, each of R
61
, R
62
, R
63
, R
64
, and R
65
being linear or branched alkyl having from 1 to 10 carbon atoms or cyclic alkyl having from 3 to 15 carbon atoms;
n, which denotes the degree of substitution of the ring to which X
1
is attached, is from 0 to 5;
m, which denotes the degree of substitution of the ring to which X
2
is attached, is from 0 to 5;
a is from 1 to 5; and
in formula (III), when one of R
2
and R
3
is hydrogen, R
2
and R
3
are different.
DETAILED DESCRIPTION OF THE INVENTION
A first aspect of the present invention is that it provides a novel polymer containing at least one pericyclic protective group G selected from formulae (I) to (V). That is to say, the polymer may contain only one group G, two groups G, three groups C, four groups G, or even five groups G. The combination of the groups G is not limited.
In formulae (I) to (V), R
1
is selected from the group consisting of linear or branched alkyl, alkenyl, alkylaryl, arylalkyl having from 1 to 10 carbon atoms, cyclic alkyl having from 3 to 15 carbon atoms, alkoxyl having from 1 to 10 carbon atoms, and
R
2
, R
3
, R
4
, and R
5
can be the same or different and are independently selected from the group consisting of hydrogen, linear or branched alkyl, alkenyl, alkylaryl, arylalkyl having from 1 to 10 carbon atoms, cyclic alkyl having from 3 to 15 carbon atoms, alkoxyl having from 1 to 10 carbon atoms, and
wherein R
11
is selected from the group consisting of hydrogen, linear or branched alkyl, alkenyl, alkylaryl, arylalkyl having from 1 to 10 carbon atoms, cyclic alkyl having from 3 to 15 carbon atoms, alkoxyl having from 1 to 10 carbon atoms, and R
12
is an alkylene group having from 1 to 10 carbon atoms.
Representative examples of R
1
, R
2
, R
3
, R
4
, and R
5
include hydrogen, methyl, ethyl, propyl, butyl, isobutyl, amyl, isoamyl, hexyl, 2-ethylhexyl, heptyl, octyl, vinyl, allyl, phenyl, and tosyl. But R
1
can not be hydrogen.
X
1
and X
2
can be the same or different and are independently selected from the group consisting of halogen, hydroxy, C
1-15
alkoxy, NH
2
, NHR
61
, NR
61
R
62
, SH, SR
63
, —(C═O)H, —(C═O) OH, —(C═O)R
64
, —(C=O)OR
65
each of R
61
, R
62
, R
63
, R
64
, and R
65
being linear or branched alkyl having from 1 to 10 carbon atoms or cyclic alkyl having from 3 to 15 carbon atoms.
Representative examples of X
1
and X
2
include fluorine, chlorine, hydroxy, methoxy, ethoxy, —NH
2
, —N(CH
3
)
2
, —SH, —SCH
3
, —(C═O)H, —(C═O)OH, —(CO)CH
3
, —(C═O) OCH
3
, and —(C═O)OC(CH
3
)
3
(t-butyloxycarbonyl).
When the polymer of the present invention contains a pericyclic protective group of formula (I) and n is 1, then preferably X
1
is t-butyloxycarbonyl, and R
1
is alkyl having from 1 to 10 carbon atoms, preferably methyl.
When the polymer of the present invention contains a pericyclic protective group of formula (I) and n is 0, then preferably R
1
is alkyl having from 1 to 10 carbon atoms, preferably methyl.
When the polymer of the present invention contains a pericyclic protective group of formula (I) and n is 3, then preferably two X
1
are halogen groups, and one X
1
is OH.
According to the present invention, the polymer can be a homopolymer or a copolymer containing at least one pericyclic protective group G as defined above. When the polymer of the present invention is a copolymer, one example can be a block or random copolymer having the repeating units (VI), (VII), (VIII), (IX), and (X):
wherein
R
71
, R
72
, and R
76
can be the same or different and are independently hydrogen, linear or branched alkyl having from 1 to 10 carbon atoms or cyclic alkyl having from 3 to 15 carbon atoms, provided that at least one of R
71
, R
72

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