Lithographic Wafer Marking Tool Reticle Alignment

The patent replaces the mechanical/laser-based direct marking system with a lithographic system that uses photosensitive materials and chemical etching. Instead of using high-energy laser pulses that physically ablate or burn marks directly into the wafer surface, the invention uses light exposure through a reticle to pattern a photosensitive layer, which then guides a controlled etching process to form the identification marks. This substitution eliminates the micro-scratches caused by laser ablation while maintaining marking capability.

The patent merges the identification mark formation process with the existing alignment mark formation process. Both types of marks are formed simultaneously using the same lithographic exposure step through a reticle that contains patterns for both identification marks and alignment marks. The photosensitive material and etching process are used for both purposes, eliminating the need for separate oxide layer formation and laser marking steps that would otherwise be required for identification marks.

The patent combines the formation of identification marks and alignment marks into a single lithographic exposure and etching process. The reticle is designed with distinct fields: one field contains the identification mark patterns, while another field contains the alignment mark patterns. During one exposure step, both fields are projected onto the photosensitive material on the wafer. Subsequent development and etching steps then simultaneously create both types of marks in the wafer surface, eliminating the need for separate processing sequences.