Process of Thin Liquid Film Formation in Spin Coating

对成膜现象进行了理论和实验分析。在这种情况下，被挥发性溶剂稀释的溶液被沉积在旋转的圆盘上，由于离心力而形成膜流，然后在整个溶剂蒸发后得到一层薄的干膜。在本文进行的理论研究中，对液膜和相邻气相进行了包括传热和传质在内的轴对称二维数值分析。在这一分析中，确定了所有变量的解形式和径向相关性。使用这些溶液形式进行了一维模拟，然后分析了从自旋到薄膜干膜形成的整个过程。在实验分析中，我们建立了旋转镀膜机，并进行了以下实验：1.在集成电路硅片上镀膜，用椭圆偏振仪测量了薄膜的厚度。2.用激光位移仪测量了加工过程中的瞬时油膜厚度。在这些实验中，用上述数值方法进行了厚度预测，并对结果进行了比较。两者吻合较好，保证了一维计算模型的有效性。3.应用Ar-离子激光阴影可视化技术对薄膜流动进行了研究，结果表明，初期观测到的表面波在整个过程中消失了。4.利用激光马赫-曾德尔干涉仪测量了薄膜的厚度分布。结果表明，涂层厚度基本均匀。

Theoretical and experimental analysis has been performed on the film formation phenomena. In this phenomena the solutions diluted by volatile solvents are deposited on a rotating disk, film flow is formed resulting from centrifugal forces, and then a thin dry film is obtained after the entire solvent evaporation.In the theoretical study performed here ; An axisymmetric 2-dimensional numerical analysis including heat and mass transfer is performed for the liquid film and the adjacent gas phase. In this analysis the solution forms and radial dependency are determined for all of the variables. A 1-dimensional modeling is performed using these solution forms and then the entire process from the spin-up to the thin dry film formation is analyzed. The behavior of the radial flow convection and the solvent evaporation, the solute concentration increase in the film, and the effect of the process parameters such as spinning speed and the initial solute concentration, are clearly shown in this analysis.In the experimental analysis a spin-coater is set up and the following experiments are performed ;1. Thin film is coated on the silicon wafer for integrated circuits and the final film thickness is measured by ellipse thickness analyzer. 2. Transient film thickness in the process is measured using laser displacement meter. For these experiments the thickness prediction by the numerical method mentioned above is performed and the results are compared. Excellent agreement is observed between them and the validity of the 1-dimensional calculation modeling is assured. 3. A shadowgraph visualization technique using argon-ion laser is applied on the film flow and showed that the surface wave observed in the initial stage vanishes in the process. 4. Mach-zehnder interferometer using argon-ion laser is applied and the distribution of the film thickness is measured. It can be concluded that almost uniform thickness is obtained.