Stencil Screens for Fine‐Line Printing

During the past decade, the thick film process has become a viable technology for the production of numerous varieties of electronic circuits. Improvements in the quality of the substrates, the thick film inks, and the manufacturing equipment have all been significant. In addition, the quality of the stencil screens has also been improved to aid the process. New types of mesh material, improved emulsion systems and better control of the screen parameters have all been realized. These refinements in the screen making materials and processes have all contributed to the feasibility for printing complex resistor and conductor networks, hybrid circuits, multilayer arrays, and sophisticated watch and display patterns. This paper will present the critical parameters of the screen mesh materials and compare the characteristics of the screen mesh materials and compare the characteristics of the nylon, polyester, stainless steel and metalized polyester fabrics. A new fine-wire 325 mesh stainless steel will be discussed and the significant impact on the technology of fine-line printing will be illustrated. In addition, recent developments in screen emulsions will be offered and pictures of fine-line patterns will be shown.