光致抗蚀剂（光刻胶）是光刻工艺中的关键基础材料，直接制约着微电子技术的发展。与美国、日本等发达国家相比，我国在光刻胶领域仍存在很大差距，高性能的光刻胶基本靠进口。本课题重点研究了新型的248-nm 光刻胶和光敏聚酰亚胺光刻胶，主要包括以下几个方面的工作： （1）提出了一种新颖且简便的制备硫鎓盐聚合物光产酸剂的方法，通过此方法可将已有的小分子硫鎓盐阳离子直接接枝到聚合物链上，利用这种曝光后产大分子磺酸的聚合物光产酸剂组成了多种新型的248-nm光刻胶。光产酸剂（Photoacid Generators, PAGs）是化学增幅型光刻胶（Chemically Amplified Resists, CARs）的关键组份，其中普遍使用的小分子产酸剂具有与成膜树脂兼容性差以及后烘过程中酸迁移比较严重等缺点，会直接影响光刻图形的分辨率和线边缘粗糙度，而采用聚合物光产酸剂可在一定程度上改善此类问题。本论文首先通过自由基聚合反应得到二元共聚物聚（对乙烯苯磺酸钠-甲基丙烯酸酯），然后将其与多种硫鎓盐卤化物通过置换反应制得一系列硫鎓盐共聚物。这种离子型硫鎓盐共聚物在常见的光刻胶溶剂中表现出较好的溶解性，热分解温度在150 °C以上，玻璃化转变温度均在130 °C以上。经曝光后能分解产生大分子磺酸，产酸效率经测定在0.31~0.34。与相应的小分子硫鎓盐相比，聚合物光产酸剂膜层的紫外吸收表现出更好的透明性。由此类硫鎓盐聚合物光产酸剂和叔丁氧羰基部分保护的聚对羟基苯乙烯（PHS）或聚（对羟基苯乙烯-甲基丙烯酸酯）为原料组成了多种两组份化学增幅型248-nm光刻胶。应用于高分辨率248-nm光刻胶，经KrF激光步进曝光实验，曝光量20~30 mJ/cm2时获得了0.2 μm线宽分辨率的图形；用于厚膜248-nm光刻胶，也得到了很好的成像结果，膜厚1.75 μm，曝光量75 mJ/cm2，线宽分辨率为0.35 μm，高宽比达到了5:1。这种硫鎓盐聚合物光产酸剂还有潜力应用于其他光刻胶体系如193-nm浸没式光刻。 以对乙烯苯磺酸钠、甲基丙烯酸酯和对乙酰氧基苯乙烯为单体通过自由基聚合制得三元共聚物，在酸性条件下，将共聚物中的乙酰氧基选择性水解变为酚羟基从而得到基于PHS的共聚物，再通过与鎓盐卤化物之间的离子置换反应将硫鎓盐阳离子引入到聚合物中得到含有硫鎓盐光产酸基团的PHS共聚物。此类PHS共聚物在稀碱水中易溶，且能够和交联剂在光产酸的作用下发生交联，可将其与交联剂一起组成248-nm化学增幅型负性光刻胶，进行了初步感光成像性能评价，在曝光量40 mJ/cm2时得到了线宽为0.35 μm的图形。 与多组份光刻胶相比，单组份光刻胶由于避免了兼容性差的问题同时具有较窄的分子量分布有利于提高成像质量。含有硫鎓盐光产酸基团的PHS共聚物和一定量的二碳酸二叔丁酯反应得到的产物同时含有硫鎓盐光产酸基团和t-BOC可酸解保护基，光照后硫鎓盐产酸基团分解生成的大分子磺酸在后烘过程中可催化t-BOC基团和叔丁酯基的分解从而显影成像，因此可将其用作单组份化学增幅型正性光刻胶材料。采用KrF激光曝光的成像实验在感度和分辨率方面都得到了很好的结果，曝光量30~40 mJ/cm2，分辨率能达到0.175 μm。 光刻工艺对金属杂质含量要求极高，以上的制备方法得到的248-nm光刻胶不可能满足实际光刻工艺的要求。为满足此类新型248-nm光刻胶的产业化需要，我们也尝试对制备方法进行了进一步改进。首先以对乙烯苯磺酸钠为原料制得了对乙烯苯磺酸甲酯，将其与对乙酰氧基苯乙烯和甲基丙烯酸酯通过自由基聚合以及选择性水解反应制得含有磺酸基的PHS共聚物，再加入适量氨水得到含有磺酸铵盐的PHS共聚物，最后通过其与鎓盐卤化物之间的离子置换反应得到含硫鎓盐阳离子的PHS共聚物。此过程可有效控制金杂含量，同时按此方法合成的光刻胶也能得到很好的成像结果。 （2）尝试制备了一种新型的N-羟基酰亚胺磺酸酯类非离子型聚合物光产酸剂。以对乙烯苯磺酸钠为原料，制备得到N-羟基邻苯二甲酰亚胺对乙烯苯磺酸酯，将其与甲基丙烯酸酯按一定比例通过自由基聚合反应制得共聚物。这种N-羟基酰亚胺磺酸酯共聚物在常见的光刻胶溶剂中具有较好的溶解性，热分解温度约为150 °C，玻璃化转变温度也在120 °C以上。光产酸基团以苯乙烯磺酸酯的方式引入到聚合物链上，在曝光后可生成大分子磺酸。由此类非离子型聚合物光产酸剂和部分四氢吡喃醚保护的PHS共聚物为原料以一定比例配制了两组份化学增幅型248-nm光刻胶，利用KrF激光曝光设备对其成像效果进行评估，曝光量45 mJ/cm2，110 °C后烘60 s得到了0.25 μm的图形。 （3）制备了多种光敏聚酰亚胺（PSPI）光刻胶材料。PSPI光刻胶可在基材上直接形成图形，在集成电路器件加工中简化整个工艺流程并提高加工精度、效率和可靠性。首先由多种芳香或脂环二酐和带酚羟基的二胺单体反应制得聚酰胺酸（PAA），再通过加热脱水反应得到聚酰亚胺（PI），最后用二碳酸二叔丁酯或环己基乙烯醚进行反应将部分酚羟基保护起来，得到含有叔丁氧羰基（t-BOC）或环己基乙烯醚（CVE）等酸敏基团的聚酰亚胺。将这些聚合物与光产酸剂等一起可组成化学增幅型聚酰亚胺正性光刻胶。此外，这些聚酰亚胺聚合物还和重氮萘醌（DNQ）感光剂（PAC）一起组成传统重氮萘醌体系聚酰亚胺正性光刻胶。采用i-线曝光设备分别对组成的新型化学增幅型和传统重氮萘醌体系光敏聚酰亚胺光刻胶的成像实验进行初步评价，获得了线宽约为5 μm的光刻图形。t-BOC保护的PI胶所需曝光量为600 mJ/cm2，后烘温度为135 °C，而CVE保护的PI胶相比之下感度较高，曝光量在300 mJ/cm2，后烘温度为110 °C即可成像。DNQ型PI胶在硅基底表面附着较差。

Photoresists are the key materials for lithography and restrict the development of microelectronic technology directly. Compared with advanced countries, mainly America and Japan, China still fall behind in the research and development of resists and the resists for advanced lithography are mostly imported products. This study focuses on the research of novel 248-nm photoresists and photosensitive polyimide (PSPI) photoresists and includes the following main parts: (1) A new and convenient way was designed to obtain sulfonium polymeric PAGs and several novel 248-nm photoresists were formed by these polymeric PAGs generating polymeric acids. With this method the existing small molecular sulfonium cations can be incorporated onto the polymeric compounds directly. Photoacid generators (PAGs) are critical components in chemically amplified photoresists (CARs), among which small molecular PAGs are commonly used but possess inherent problems such as incompatibility with matrixes and acid migration during post exposure baking (PEB). These problems do harm to the improvement of the resolution and line edge roughness (LER), while polymeric PAGs would be better choices for CARs to acquire excellent photolithographic performance. Copolymer poly (sodium p-styrenesulfonate-co-methacrylate) was firstly prepared through free radical polymerization and then further reacted with various sulfonium halides to give a series of sulfonium salt copolymers. The ionic sulfonium copolymers displayed good solubilities in common resist solvents. The thermal decomposition temperatures were around 150 °C and the glass transition temperatures were above 130 °C. These copolymers could generate polymeric photoacids under exposure and the photoacid generation efficiencies were determined around 0.31~0.34. UV absorbances showed big difference between small molecular sulfonium salts and the corresponding polymeric PAGs, and the latter displayed better transparency. Two-component 248-nm CARs were formed by one of the polymeric PAGs and partly protected poly (4-hydroxystyrene) (PHS) or poly (4-hydroxystyrene-co-tertiary-butyl methacrylate). Applied in 248-nm high resolution patterning, pattern with line/space (L/S) resolution of 0.2 μm was obtained under exposure of 20~30 mJ/cm2 with KrF laser stepper. When used for thick film 248-nm resists, good performance with high height/width (H/W) ratio of 5:1 was obtained. The resolution was 0.35 μm under exposure of 75 mJ/cm2 with the resist film thickness of 1.75 μm. These polymeric PAGs also have potentiality to be used in CARs for other photolithography technologies such as 193-nm immersion technology. Terpolymer of sodium p-styrenesulfonate, methacrylate and acetyloxystyrene was prepared by free radical polymerization and then a new type of PHS copolymer was obtained through the selected hydrolysis of acetoxyl groups to phenolic hydroxyl groups under acidic condition. After that, the PHS copolymer containing sulfonium PAG was obtained with sulfonium cations incorporated onto polymer by the exchange reaction between PHS copolymer and sulfonium halides. This copolymer displayed good solubility in dilute aqueous base and could undergo cross link reaction with suitable crosslinking agents under the present of photoacids. Negative 248-nm CAR was formed by this sulfonium polymeric PAG and adequate crosslinking agents, and a pattern with resolution of 0.35 μm was obtained with the exposure dose of 40 mJ/cm2. Compared with two or more component CARs, the one-component CARs would probably be better choice to improve lithographic performance as they do not bring in incompatibility and have narrower molecular distribution. The PHS copolymer containing sulfonium PAGs was reacted with adequate di-tert-butyl dicarbonate ester to give a type of PHS copolymer containing both sulfonium PAGs and t-BOC protections which could be applied for one-component CARs. The photogenerated polymeric sulfonic acids catalyzed the decoposition of t-BOC protections and tertiary butyl ester groups during PEB, thus positive-tone patterns could be obtained after development. The photolithography of this one-component resist was evaluated with KrF laser stepper and showed outstanding performance in resolution and photosensitivity, SEM pattern with resolution of 0.175 μm was obtained under exposure of 30~40 mJ/cm2. The photolithography process requires extremely low content of metal impurities, however, the resists obtained by the above methods cannot meet the requirements of the actual photolithography process. Therefore we tried to improve the preparation method in order to make the new type of 248-nm CARs meet the industrialization needs. With sodium p-styrenesulfonate as a raw material, methyl 4-vinyl benzenesulfonate was prepared and then further copolymerized with acetyloxystyrene and methacrylate monomers to obtain copolymers through free radical polymerization. Then a new type of PHS copolymer containing sulfonic acid ammonium groups was obtained through the selected hydrolysis and followed by adding moderate ammonium hydroxide. After that, this PHS copolymer was further reacted with the sulfonium halides to give a PHS copolymer containing sulfonium PAGs. This method effectively controlled the content of metal impurities, and the photoresist synthesized by this way also achieved a good imaging result. (2) A new type of nonionic N-hydroxyl imide sulfonate polymeric PAGs was prepared. With sodium p-styrenesulfonate as a raw material, N-4-vinyl benzenesulfonoxy phthalimide ester was prepared and then further copolymerized with methacrylate monomers to obtain copolymers through free radical polymerization. The copolymers with nonionic sulfonate PAG units displayed good solubilities in common resist solvents. The thermal decomposition temperature was around 150 °C and the glass transition temperatures was about 129 °C. The N-hydroxyl imide benzenesulfonate PAG unit was incorporated onto the polymers and generated polymeric sulfonic acid under exposure. Two component 248-nm CARs were formed by this nonionic N-hydroxyl imide sulfonate copolymer and PHS copolymer with tetrahydropyran (THP) protections. The photolithography was conducted on the KrF laser stepper, under exposure of 45 mJ/cm2 and followed by 110 °C PEB for 60 s, a pattern of 0.25 μm line width is acquired. (3) Several photosensitive polyimide (PSPI) photoresists were prepared. PSPI can pattern directly on the substrate, which will simplify the lithography process and enhance accuracy, efficiency and reliability. Polyamide acid (PAA) was firstly prepared by the polymerization of the monomers of dianhydrides and diamines containing phenolic hydroxyl groups, and then followed by succedent imidization to give polyimide (PI). The PI polymer was further reacted with di-tert-butyl dicarbonate or cyclohexyl vinyl ether to protect a part of the phenolic hydroxyl groups and then PI polymers with moderate acidolytic t-BOC or CVE protections were obtained. A new kind of positive CARs were formed with this PI polymers and suitable PAGs. In addition, the conventional DNQ type photoresists was formed with the PI copolymers and diazonaphthoquinone (DNQ) sulfonate photoactive compound (PAC). The patterning performances of the CARs and conventional DNQ type resists were evaluated preliminarily by the UV light lithography and obtain good imaging patterns with resolution of 5 μm. Compared with t-BOC system, the CVE system showed better sensitivity and the PEB temperature was 110 °C which far below 135 °C for t-BOC system. The adhesion of the DNQ type PI resists on silicon substrate was poor.