The semiconductor industry requires high definition, highly legible markings on semiconductor parts which may be made of various materials. The prints must withstand solvents, solder flux, heat, and abrasion without becoming illegible. Gravure printing, the traditional approach, requires wet inks and printing plates and does not offer the flexibility of digital printing. Laser marking is increasingly used and offers digital printing advantages, but legibility of direct laser prints is poor because of lack of satisfactory contrast mechanisms.We have developed and sold a novel laser thermal transfer marking system for this application which allows dry, high contrast, durable, 500 dot/inch digital prints to be made on silicon, nickel, gold, ceramic and epoxy surfaces. The images are cured with UV or thermal energy. This process required the design of a novel laser printing head which is capable of applying proprietary thermal transfer foil onto small parts while exerting a minimum of force on the parts.We will present the requirements for the application, some of the technical approaches that were tried for design of the marking engine, and describe the solutions selected.
Alan Boyer, Stephen Carter, "Laser Thermal Transfer Printing with Curable Inks" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP16), 2000, pp 113 - 117, https://doi.org/10.2352/ISSN.2169-4451.2000.16.1.art00030_1