In this paper, the effects of coating conditions on the thickness and quality, especially the hardness and density, of a photoresist film are reported. The photoresist film was deposited on a Si wafer by a spin coater under various conditions, including baking temperature, rotation speed, and the number of coats. The thickness of the film was measured by a surface profilometer. The sound velocity, which is closely related to hardness, and the density of the film were obtained by acoustic resonant imaging technique. The thickness and sound velocity of the film increased with increasing the number of coats and decreased with increasing the baking temperature and the rotation speed. Furthermore, the density of the film reached its maximum value for each condition. From multiple regression analysis, it was found that, among the three parameters of coating conditions, the rotation speed affects the quality of the film the most. It was shown that a dense photoresist film is obtained by deciding the baking temperature and number of coats in advance, then choosing a suitable rotation speed.

中文翻译：

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声共振成像技术评价厚光刻胶膜的质量

在本文中，报告了涂层条件对光刻胶膜的厚度和质量，尤其是硬度和密度的影响。在各种条件下，包括烘烤温度、旋转速度和涂层数量，通过旋涂机将光刻胶膜沉积在Si晶片上。膜的厚度通过表面轮廓仪测量。与硬度密切相关的声速和薄膜的密度是通过声共振成像技术获得的。薄膜的厚度和声速随着涂层次数的增加而增加，随着烘烤温度和转速的升高而降低。此外，薄膜的密度在每种情况下都达到了最大值。通过多元回归分析发现，在镀膜条件的三个参数中，转速对镀膜质量的影响最大。结果表明，通过预先确定烘烤温度和涂层数量，然后选择合适的转速可以获得致密的光刻胶膜。