紫外可见光谱法测量光刻胶的膜厚

在液晶显示器的制造过程中,光刻是极为重要的制造工艺过程之一。将厚的独立的负胶膜或者将光刻胶涂敷在二氧化硅衬底上以后,可以测量其膜厚,因为光刻胶膜厚决定其光刻工艺的工艺条件。能够快速地测量光刻胶的膜厚,是液晶显示器制造过程的先决性工作的一部分。文章提出了测量上述光刻胶膜厚的新方法,即利用紫外可见吸收光谱法中的Beer-Lambert定律来确定膜厚。在我们的研究中,采用acrylic负胶作为基质(resin) ,它分别具有50μm和100μm的膜厚。在350 nm时,50μm的薄膜的最大吸收为0 .728 ,而100μm的最大吸收为1 .468 5。而在正胶的研究中,采用novolac作为基质(resin)。它的膜厚通常是1 ～5μm。在紫外可见吸收光谱测膜厚的实验中,当重氮荼醌的吸收波长为403 .8 nm时,5 .93μm厚的薄膜的最大吸收为1 .757 4 ,其膜厚是由扫描电镜测得的。而另一个正胶薄膜在403 .8 nm的最大吸收为0 .982 3 ,其薄膜厚度计算得到为3 .31μm。利用这些数据,我们得到了这两种光刻胶薄膜的紫外可见吸收光强与其膜厚关系的两个校准曲线。

UV-vis Spectroscopy Study of Resist Film Thickness

A new method to measure the resist film thickness is proposed, which is, to use the Beer-Lambert's Law to determine the film thickness, using the UV-visible spectroscopy. The negative photoresist in this study uses the acrylic as the resin, which has the film thickness of 50 μm and 100 μm, respectively. It is observed that the absorbance maximum at 350 nm for 50 μm thick "dry" resist film is 0.728 while the absorbance maximum at the same wavelength for 100 μm thick resist is 1.468 5. Here the positive photoresist uses the novolac as the resin while the film thickness in this study is typically between 1～5 μm. In this particular experiment, the absorbance is 1. 757 4 at 403. 8 nm while the film thickness is measured to be 5.93 μm through the scanning electron microscopy. Another resist film has the absorbance of 0. 982 3 at 403.8 nm and the film thickness is 3.31 μm.