A combinatorial research methodology is discussed to determine the material factors that control line edge roughness (LER), shape, and critical dimension (CD) of developed photo-resist features. The approach involves generating a gradient of processing variables in the photo-resist film and using a set of microscopy tools to 'map' the photo-resist properties as a function of this gradient. Photo-resist lines will be developed in different regions of the film. SEM analysis of the line structure combined with the microscopy mapping, and knowledge of the gradient variables provides a mechanism to rapidly relate processing variables, photo-resist film properties, and the LER / CD of developed features. While this combinatorial methodology could prove useful for empirical optimization of processing conditions, our focus will be to determine the fundamental polymer science issues that govern LER / CD. Initial data is presented that illustrates the potential of the combinatorial research concept for dramatic reductions in research and development cycles times. In particular, the thermal de-protection curve of a model photo-resist system was rapidly developed using a high throughput combinatorial technique. Thermal degradation of the resist was verified with traditional experimental design by using a combination of specular x-ray reflectivity (SXR), atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR). Integration of combinatorial techniques with non-combinatorial tools provides a unique methodology with the potential to rapidly disseminate important factors that govern LER and CD.
Citation: Journal of Vacuum Science and Technology B
Pub Type: Journals
combinatorial, deprotection, line edge roughness, photolithography, photoresist, polymer