Advanced Micro-Optics Solutions for Laser-Based Semiconductor Processes

Optical technologies are crucial and widely used in semiconductor technology. Compared to traditional approaches with macro-lenses micro-optics solutions offer new possibilities for all kinds of semiconductor manufacturing. With refractive free-form micro-lenses a large variety of beam shapes can be generated where top hat profiles with homogeneous intensity distributions are the most prominent ones. Beam shaping principles of micro-lens systems are outlined and four prominent application examples are demonstrated. The most famous process is optical lithography where tiny structures down to 32 nm or even below are feasible. Homogeneous off-axis illumination becomes possible due to asymmetrical micro-lens arrays which can be utilized in various illumination and inspection systems. The laser-based structuring of trenches, e.g. wafer scribing and dicing, is significantly enhanced by top hat compared to Gaussian beam profiles. Laser-based annealing results are shown on silicon for a green laser line and a near-infrared line generator.