一种耐高温紫外正型光刻胶及光刻工艺

The composition and photolithographic process of high-thermostability ultraviolet positive photoresist

光刻胶作为光刻技术中的关键性基础材料,其配方组成和光刻工艺对光刻胶的分辨率等性能有重要影响.以自制的酰胺-酰亚胺聚合物作为成膜树脂,与感光剂2,1,5-磺酰氯的衍生物等其他成分按一定比例配制成光刻胶,通过研究不同配比、不同光刻工艺条件下的光刻性能,得到了该光刻胶的最佳配方组成及最佳光刻工艺条件.该光刻胶的成像反差可达到约3.35;在最佳配方组成和最佳光刻工艺条件下,采用接触式曝光,可以获得最大约1?m的线宽分辨率,同时该光刻胶具有良好的耐热性,270℃高温下坚膜30 min,光刻图形未发现明显塌边现象.

Photoresist is a crucial and fundamental material for photolithographic technology, which plays a vital role in microelectronic technique. The rapid development of lithography drives the microelectronic technique moving forward. With high-level and multifunctional photoresist, it can make finer patterns and meet the demand under harsh working environment such as high temperature. To evaluate the performance of the photoresist, one of the most important indicators is line/space resolution, while the composition of the photoresist and photolithographic process have a very significant influence on the resolution performance. Different composition may result in different photosensitivity and solubility of the photoresist, which have a significant impact on the performance. Moreover, the photolithographic processes include exposure dose（exposure time）, developing time, the concentration of developer and so on. They all have severely affected the lithography pattern quality and lithography performance. Thus, the related research in detail is very necessary and it is conducive to maximize the performance of the photoresist and guide lithography process to be carried out smoothly as well. In this work, a high thermal-stability ultraviolet（UV） positive photoresist was obtained from the formulation of a self-made amide-imide copolymer as matrix resin, a 2,1,5-diazonaphthoquinone sulfonyl chloride derivative as photosensitizer, and solvent. The optimal composition and photolithographic process parameters was studied by simple variable method. It was found that the optimal composition was with the 1：4：10（mass ratio） proportion of photosensitizer, resin and solvent, and the optimal photolithographic process parameters were about 4500 r/min spin-coating, prebake 1 min at 110°C hot plate, 30 s exposure time, 25 s development time in 1.0% tetramethylamine hydroxide（TMAH） aqueous solution, and post bake 5 min at 120°C hot plate. The imaging contrast of this photoresist was about 3.35, which indicated that the positive part and negative part of the pattern had obvious boundary. In the condition of contact exposure the lithography process above, the optimal line/space resolution was about 1 μm. In addition, the photoresist had high thermal-stability. After hard baking 30 min at 270°C, the photoresist had no obvious collapse of the photolithography pattern. This is because the self-made amide-imide copolymer has high thermal-stability and it acts as matrix resin in the photoresist. With the high thermal-stability property, the photoresist can meet the requirements of some used under high temperature environment and lays a foundation for the lithography technology being applied and developed under complex circumstance.