2 results
Photoimaging Materials Based on Base-amplifying Silicone Resins Having Phenylsulfonylethyl Groups
- Satoru Inoue, Koji Arimitsu, Takahiro Gunji, Yoshimoto Abe, Kunihiro Ichimura
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- Journal:
- MRS Online Proceedings Library Archive / Volume 961 / 2006
- Published online by Cambridge University Press:
- 01 February 2011, 0961-O11-06
- Print publication:
- 2006
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- Article
- Export citation
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Recently, the large number of investigations concerning acid-catalyzed photopolymer systems such as chemically amplified photoresists and UV-curing materials has been reported. On the other hand, analogous systems utilizing base-catalyzed reactions have received far less attention, because low quantum yields for photobase generation to lead to low photosensitivity of these systems. To improve this problem, we proposed introduction of the concept of base proliferation reactions into the photopolymer systems using base-catalyzed reactions. The concept involves the autocatalytic base-catalyzed decomposition of a compound, referred to as a base amplifier which releases a newborn amine, leading to its autocatalytic decomposition. In fact, the addition of the base amplifiers such as 9-fluorenylmethyl carbamate, phenylsulfonylethyl carbamate, and 3-nitropentane-2-yl carbamate to a photopolymer consisting of an epoxy polymer sensitized and a photobase generator (PBG) resulted in the marked improvement of photosensitivity.
However, these base amplifiers with low molecular weight are not suitable for photopatterning because of the volatility and the excessive diffusion of amines proliferated in polymer films. We report here novel base-amplifying silicone resins tethering phenylsulfonylethyl carbamoyl groups which proliferate primary amino groups or secondary amino groups in their side chains.
Base-catalyzed decomposition behavior of films of these resins containing PBG was evaluated by UV absorption measurements. A film consisting of the resin proliferating primary amino groups and 10 wt% of PBG decomposed immediately in a nonlinear manner by 365 nm irradiation and subsequent heat treatment at 120oC for 6 min. On the other hand, this film without UV irradiation was thermally stable for 18 min at 120oC. These results indicate that photoinduced base proliferation reaction of the resin proceeded. A film consisting of the resin generating secondary amino groups and PBG decomposed in a way similar to that of the resin proliferating primary amino groups. Furthermore, lithographic evaluation of the film comprising the resin to generate secondary amines and PBG obtained 7ÊS positive images with an exposure dose of 75 mJ/cm2 which shows higher sensitivity when compared to conventional base-catalyzed photopolymers.
Application of Novel Base Amplifiers with 3-Nitropentan-2-yl Group to Photoreactive Materials
- Koji Arimitsu, Yusuke Ito, Takahiro Gunji, Yoshimoto Abe, Kunihiro Ichimura
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- Journal:
- MRS Online Proceedings Library Archive / Volume 961 / 2006
- Published online by Cambridge University Press:
- 01 February 2011, 0961-O11-05
- Print publication:
- 2006
-
- Article
- Export citation
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In order to enhance the photosensitivity of photoreactive materials utilizing base-catalyzed reactions, we developed base amplifiers that decompose autocatalytically to generate newborn amine molecules. Actually, we reported that the addition of base amplifiers to the photoreactive materials such as photoresists and UV-curing materials resulted in the marked improvement photosensitivity. However, conventional base amplifiers have aromatic rings such as fluorenyl groups and phenyl groups. Consequently, these base amplifiers have strong absorption of UV light which is a trigger of photolysis of a photobase generator. This leads to the hindrance of the photolysis. We report here novel base amplifiers with 3-nitropentan-2-yl group which has no aromatic rings.
The base amplifiers decomposed autocatalytically to generate newborn amine molecules at an elevated temperature in solution and a polystyrene film in the presence of a catalytic amount of amines. Moreover, combining the base amplifiers with UV-curing materials consisting of a photobase generator and liquid epoxy resins resulted in the improvement of curing efficiency. To apply the base amplifier to photopatterning materials, we synthesized novel silicone resins with 3-nitropentan-2-yl groups as base-amplifying polymers. A film of the resin decomposed autocatalytically to generate amino groups in its side chains at an elevated temperature in the presence of a catalytic amount of amines. Furthermore, we demonstrated that the resins sensitized with a photobase generator provided negative- and positive-working photopolymers in the following ways. A thin film of the resin containing 10 wt% of a photobase generator became soluble in an acidic aqueous solution after 254 nm light irradiation of an exposure dose of 1 mJ/cm2 and subsequent baking at 50 oC for 20 min. This is because of formation of amino groups in its side chains. On the other hand, the film became insoluble in organic solvents after 254 nm light irradiation of an exposure dose of 1 mJ/cm2 and subsequent heat treatment at 50 oC for 40 min, this arises from that the photobase-catalyzed hydrolytic condensation of residual ethoxysilyl units of the resin proceeded to form crosslinked networks.