Methods for Determining the Effective Order of Absorption in Radical Multiphoton Photoresists: A Critical Analysis
Methods for Determining the Effective Order of Absorption in Radical Multiphoton Photoresists: A Critical Analysis
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DOI：
10.1002/lpor.202000203
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发表时间：
2020-11
影响因子：
11
通讯作者：
N. Liaros;J. Fourkas
中科院分区：
文献类型：
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作者：
N. Liaros;J. Fourkas
自由基光致抗蚀剂中多光子吸收聚合的有效吸收阶数（EOA）的准确测定对于具有改进的灵敏度和/或分辨率的新材料的开发和表征是至关重要的。然而，EOA的可靠测量是一个具有挑战性的问题。四种技术，已经开发出来，以解决这个问题的准确性进行了分析，在已知的动力学的多官能单体的自由基聚合。它表明，方法是基于充分的互惠性，即，光致抗蚀剂的化学响应取决于曝光剂量而不取决于该剂量被传递的时间段的概念，仅使得能够在高度受限的一组环境下可靠地确定EOA。依赖于有限互易性的方法，即，当总曝光窗口恒定时，光致抗蚀剂的化学响应是相同的，即使在该窗口内曝光的细节变化，这一概念可以使得能够在相当宽的操作条件范围内精确确定EOA。这一预测得到了实验验证。这里提出的分析为未来的实验提供了指导，并为更清晰地解释先前发表的结果提供了基础。
The accurate determination of the effective order of absorption (EOA) for multiphoton absorption polymerization in radical photoresists is critical for the development and characterization of new materials with improved sensitivity and/or resolution. However, reliable measurement of the EOA is a challenging problem. The accuracy of four techniques that have been developed to address this issue is analyzed in terms of the known kinetics of the radical polymerization of polyfunctional monomers. It is demonstrated that methods that are based upon full reciprocity, i.e., the concept that the chemical response of the photoresist depends on the exposure dose, but not on the period over which this dose is delivered, only enable reliable determination of the EOA under a highly constrained set of circumstances. Methods that depend on limited reciprocity, i.e., the concept that the chemical response of the photoresist is the same when the total exposure window is constant, even if the details of the exposure within that window are varied, can enable accurate determination of the EOA over a considerably broader range of operating conditions. This prediction is verified experimentally. The analysis presented here provides guidance for future experiments and a basis for clearer interpretation of previously published results.