Alicyclic dissolution inhibitors and positive potoresist...

Details Alicyclic dissolution inhibitors and positive potoresist... Alicyclic dissolution inhibitors and positive potoresist...

2000-04-03

2001-07-24

Ashton, Rosemary E. (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

C430S908000, C560S116000, C562S498000

Reexamination Certificate

active

06265131

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to the lithography field, and more particularly to positive photoresist composition including dissolution inhibitors, and to dissolution inhibitors for such formulations.
BACKGROUND OF THE INVENTION
Current semiconductor industry trends indicate that the development of high performance logic processors and 1-Gbit DRAM will require the availability of below 0.18 &mgr;m lithographic processes. In theory, two methods of forming finer resist patterns are to shorten the wavelength of an exposure light source and increase the numerical aperture (NA) of an exposure system.
Semiconductor industry implemented in manufacture of devices by deep UV lithography employing a KrF excimer laser (248 &mgr;m) stepper for 0.25 &mgr;m process. Due to the optical enhancement techniques such as high NA optical elements, phase shift mask, etc. The appearance of 248 &mgr;m KrF scanner offers the pilot-run of 0.18 &mgr;m process and development of below 0.15 &mgr;m process. However, there is a limit of wavelength shorten, the more difficult of mask produced. In order to minimize the device size, efforts to develop 193 &mgr;m (ArF excimer laser) lithography and resists have been tremendously accelerated in the last several years.
In addition to improved resolution, it is also desirable to provide positive resist materials having improved sensitivity. One approach to improving sensitivity uses the concept of chemical amplification. Chemical amplification involves the photogeneration within the resists of species that catalyze subsequent chemical events. One method of chemical amplification includes dissolution inhibition, wherein a masked phenol or protected carboxylic acid is mixed with a phenolic resin, resulting in a drastic decrease in the dissolution rate of the polymer in aqueous base developing solutions. A photoactivated acid-catalyzed deprotection reaction is then used to free the phenol or the carboxylic acid. As a result, the dissolution inhibitor is converted into a dissolution promoter in the radiation exposed areas of the resist material, allowing for the development of positive images.
There remains a need in the art for a positive photoresist composition having both high resolution and high sensitivity. There also remains a need in the art of composition for positive photoresist, which are useful in deep-UV image resolution techniques. Moreover, there remains a need in the art for positive photoresist dissolution inhibitors capable of providing high sensitivity.
SUMMARY OF THE INVENTION
The positive photoresist composition of the present invention comprises a polymer, a photoactived agent, and a dissolution inhibitor.
The dissolution inhibitor may be represented by the following formula (I):
wherein R
1
and R
2
each independently is a hydroxyl group, a C
1-8
hydroxyalkyl group, or a C
3-8
hydroxycycloalkyl group; R
3
, R
4
and R
5
each independently is a hydrogen, a C
1-8
hydroxyalkyl group, a C
1-6
carboxylic acid or a C
3-8
carboxylic acid ester; k is an integer of 0, 1, 2, 3, 4, 5 or 6.
DETAILED DESCRIPTION OF THE INVENTION
The positive photoresist composition of the present invention includes a polymer, a photoactived agent, and a dissolution inhibitor.
Suitable polymers for use in the present invention will be known to those skilled in the art. Preferably, the polymers will be transparent in at least a portion of the ultraviolet region of the electromagnetic spectrum. As used herein, the term “transparent” refers to a 500 &mgr;m thickness of polymer which essentially has an optical density of not more then 2.0 um
−1
in the wavelengths between about 190 &mgr;m and about 440 &mgr;m. Preferably, a 500 &mgr;m sample of the polymer has an optical density of not more than 2.0 um
−1
at one or more of the following wavelengths: 193 &mgr;m, 248 &mgr;m, 254 &mgr;m, and 365 &mgr;m.
Polymers which are useful in the present invention are generally soluble in an aqueous base solution after being UV irradiated. Any suitable polymers known to those skilled in the art may be employed in the practice of the present invention. Typically, suitable polymers include a unit structure represented by the following formula (14), (15) and (16):
wherein R is a hydrogen or a C
1-4
alkyl group; R′ is a hydrogen or a C
1-4
alkyl group.
Preferred examples of said polymers include the following formula (2) to formula (10),
wherein l+m+n=1 or l+m+n+o=1 or l+m=1.
Any suitable photoactived agent known to those skilled in the art may be employed in the practice of the present invention. As used herein, the term “photoactived agent” refers to a compound whose chemical composition is altered upon exposure to radiation. Preferred photoactived agents include photoacid generators. Photoacid generators produce acid upon exposure to radiation. Photoacid generators, which are suitable for the present invention typically, produce strong acid upon exposure to radiation. There is no special limit to photoacid generators here. The photoacid generator suitable for the chemical amplified photoresist composition of the present invention meet the requirement to maintain stability before exposure. Preferably, suitable photoacid generators are:
The positive photoresist composition of the present invention can further include acid scavengers to adjust the diffusion of acid. Suitable acid scavengers can be
The photoresist further includes a dissolution inhibitor of the formula (1)
wherein R
1
and R
2
each independently is a hydroxyl group, a C
1-8
hydroxyalkyl group, or a C
3-8
hydroxycycloalkyl group; R
3
, R
4
and R
5
each independently is a hydrogen, a C
1-8
hydroxyalkyl group, a C
1-6
carboxylic acid or a C
3-8
carboxylic acid ester; and k is an integer of 0, 1, 2, 3, 4, 5 or 6.
The ratio of each component of the present invention can be changed in wide a range. In general, the minimum relative weight percentage for each component is 1%, ant the maximum relative percentage is 98%. The composition of the present invention preferably contains polymer 10-98% by weight, photoactived agent 1-50% by weight, and dissolution inhibitor 1-50% by weight.
The positive photoresist composition of the present invention can be used to obtain chemical amplified photoresist. The positive photoresist of the present invention can be obtained by simply mixing the components together. There are no limits for the mixing methods. The positive photoresist composition of the present invention can be made by either adding other components into the solution of the photosensitive polymers (or copolymers) or adding the photosensitive polymers (or copolymers) into the solution of other components.
The impurities (e.g. trace amount of metal cations or halides) of the positive photoresist composition of the present invention should be removed as well as possible. The impurities in the components of the positive photoresist composition of the present invention can be removed before or after the components are mixed together.
The positive photoresist composition of the present invention can be used in the process of lithography. Especially, the positive photoresist composition of the present invention can be used in the process of 193 &mgr;m and 248 nm (ArF and KrF excimer laser) lithography. After the positive photoresist composition of the present invention is proceeded through normal lithographic procedures such as coating, exposure and development, patterns on substrates will form. As the positive photoresist composition of the present invention are used, the compositions are coated on a substrate first. Then the coating is baked to remove solvents, and exposed to a light source under masks to form patterns. The substrate used for 193 &mgr;m and 248 nm lithography here can be silicon or other materials. The coating methods to coat the positive photoresist composition of the present invention on substrates can be spin coating, spray coating and roll coating.
The developing solutions for the exposed resist coating can b

Affiliated with

Also associated with

Rating

Alicyclic dissolution inhibitors and positive potoresist... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Alicyclic dissolution inhibitors and positive potoresist..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Alicyclic dissolution inhibitors and positive potoresist... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2559337