Study on Optimal Property and Photolithography of Negative-work and Transparent Photosensitive Polyester Acrylate

• Main Authors: Kun-Lin Hsu, 許坤霖
• Other Authors: 鄭文桐
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/39160603829003084774

碩士 === 國立中興大學 === 化學工程學系所 === 104 === In recent years, the use of smart 3C product is tend to occupy our life in the global. Therefore, the development of the optoelectronics industry more and more focus on new touch panel technology. Among them, one glass solution (OGS) is a kind of outstanding method to overcome difficulties. It allows complex modules stacked structure turn to slim type. Currently, the physical properties of negative-tone photosensitive transparent insulation materials are still insufficient. In this study, we select hardness and adhesion properties as targets for Taguchi method to find the optimal formulation and process. The experiment is mainly divided into two parts in this study. Firstly, we designed L9 (34) orthogonal array experiments to optimize the ratio of monomers, amount of photoinitiator, exposure dosages, and post baking temperature for the polymer solution composed from propylene glycol monomethyl ether acetate (PGMEA), polyester acrylate oligomer, photoinitiator (Irgacure 500), reactive monomers of dipentaerythritol hexaacrylate (DPHA) and tri (propylene glycol) diacrylate (TPGDA) to obtain the excellent hardness and adhesion of photopolymeric film through Taguchi method associated with analysis of variance (ANOVA). Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) are to be also employed to examine thermal resistance and degree of photo-polymerization, respectively, after casting film in this work. Secondly, photolithography characteristics of the photoresist films under different solid content can be used to evaluate sensitivity and contrast. Also, the optical microscope (OM) was used to observe the pattern resolution of the line width. As shown in results, the significant findings of this study could be remarked as below: (1) The optimal conditions of formula and process are 20phr/15phr of DPHA/TPGDA, 2phr of Irgacure 500, 1200mJ/cm2 of UV dosage, and post baked temperature in furnace at 200℃ respectively, resulting in the transparent photosensitive polyester acrylate both with the pencil hardness of 3H and the cross-cut adhesion of 5B. (2) The conversion of transparent photosensitive polyester acrylate film at 1µm reach 84% after irradiating with 1800 mJ/cm2 of UV light, as measured by FTIR. (3) As measured by TGA, the thermal decomposition temperature of transparent photosensitive polyester acrylate film with thickness of 1µm will increase from 382℃ to 396℃ and from 379℃ to 396℃ but decrease from 396℃ to 366℃, as the content of DPHA was varied from 15phr to 20phr, the UV exposure was changed from 600mJ/cm2 to 1200mJ/cm2 , and amount of I500 was raised from 2phr to 6phr, which were caused by heat diffusion inhibition effect due to higher crosslinked density and residual photoinitiator resulted in deterioration effect after photo-polymerization respectively. (4) When the solid content of the negative-work photoresist with thickness of 1µm was varied from 16.2wt.% to 25.9wt.%, for the film thickness without reduction, the requirement of exposure dosages would increase from 68 mJ/cm2 to 90 mJ/cm2, resulting in the contrast would be decreased from 1.26 to 0.68 due to the higher viscosity of photoresist to slow the polymerization rate. (5) By OM observation, the ratio of line width to space for negative patterns with solid content of 19.7wt.% and film thickness of 1µm is 1.1 after irradiating by 600mJ/cm2 of exposure dosage, followed by development with 0.01wt.% KOH in de-ionic water for 30 seconds.