A New Monocyclic Fluoropolymer for 157-nm Photoresists
A New Monocyclic Fluoropolymer for 157-nm Photoresists
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用于 157 nm 光刻胶的新型单环含氟聚合物
DOI：
10.2494/photopolymer.17.639
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
T. Itani
中科院分区：
文献类型：
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作者：
Sasaki Takashi;Y. Takebe;M. Eda;Osamu Yokokoji;S. Irie;Akihito Otoguro;K. Fujii;T. Itani
我们早期开发了一系列含氟聚合物（FPR），用作第一代157 nm光刻胶聚合物。这些FPR具有部分氟化的单环结构并提供优异的透明度。然而，它们的抗蚀刻性低（传统KrF抗蚀剂的一半）并且在四甲基氢氧化铵（TMAH）溶液中的溶解速率不足。为了改善这些聚合物的特性，同时保持高透明度，我们必须重新设计主链含氟聚合物结构。在本文中，我们描述了一种新的单环含氟聚合物结构的第二代157纳米光致抗蚀剂聚合物。该结构在聚合物主链中还具有氟原子，以及含氟酸性醇基团。我们合成了两种类型的含氟聚合物，ASF-1和ASF-2。结果表明，ASF-1薄膜的透光率为0.18 μm-1，比普通玻璃薄膜的透光率高，抗腐蚀性也有所提高。不幸的是，溶解速率很差。另一方面，ASF-2显示出0.1 μm-1的更好的透明度，改善的耐蚀刻性，以及超过600 nm/s的溶解速率，这足以用作抗蚀剂。引入保护基（例如，甲氧基甲基或金刚烷基甲氧基甲基）与ASF-2的羟基的连接可以在聚合反应之后进行。使用具有适当保护基的部分保护的ASF-2，我们能够制造亚60 nm的线和空间图案。
We earlier developed a series of fluoropolymers (FPRs) for use as first-generation 157-nm photoresist polymers. These FPRs have a partially fluorinated monocyclic structure and provide excellent transparency. However, their etching resistance is low (half that of conventional KrF resists) and an insufficient dissolution rate in tetramethylammonium hydroxide (TMAH) solution. To improve the characteristics of these polymers, while retaining high transparency, we had to redesign the main chain fluoropolymer structure. In this paper, we describe a new monocyclic fluoropolymer structure for a second-generation 157-nm photoresist polymer. This structure also has a fluorine atom in the polymer main chain, as well as a fluoro-containing acidic alcohol group. We synthesized two types of fluoropolymers, ASF-1 and ASF-2. We found that ASF-1 had transparency of 0.18 μm-1, better than that of the FPRs, and the etching resistance was improved. Unfortunately, the dissolution rate was poor. On the other hand, ASF-2 showed even better transparency of 0.1 μm-1, improved etching resistance, and a dissolution rate of more than 600 nm/s, which is sufficient for use as a resist. The introduction of a protecting group (e.g., the methoxymethyl or adamantylmethoxymethyl group) to the hydroxyl group of ASF-2 can be done after the polymerization reaction. Using partially protected ASF-2 with an appropriate protecting group, we were able to fabricate a sub-60-nm line-and-space pattern.