Advances in Mask Making Technology
Precision Micro Ltd has developed new manufacturing technologies that increase the resolution and improve the aperture quality in the deposition masks used extensively in the production of flat and flexible panel displays and for depositing gold and silver traces onto quartz crystals.
Using its LEEP & LEEF process techniques, the Company can now produce cost-effective nickel, stainless steel and invar masks which out-perform traditional alternatives. The techniques combine low preparation costs with superior tolerances, delivering greater density designs with higher accuracy.
Each individual mask can contain as many as several million apertures, each down to 10 microns in diameter but the number of apertures is not reflected in the cost of manufacture, as all the detail is chemically etched or electroformed simultaneously.
Masks produced with LEEF or LEEP technology are burr-free, stress-free and completely flat whereas masks produced by laser cutting, the alternative manufacturing method, are subjected to thermal excursions during the manufacturing process that can cause stress and distortion in the material.
In order to virtually eliminate photo shadow and optimise deposit definition, it is imperative that the masks should have the thinnest possible cross-section in the pattern area. Using honed, multi-level techniques, Precision Micro can produce masks down to 10 microns thick with substantial reinforcement in non-patterned areas to enhance durability. ‘Pockets’ can also be formed into the mask to hold components, such as crystals, in-place during the deposition process.
During the deposition process the masks become coated with whatever material is being deposited, reducing aperture size and edge definition. Cleaning, to remove this residue, can wear or damage the mask over time. Precision Micro uses stainless steel or electroformed hard nickel for optimum resistance to the harsh chemicals used in this post-deposition cleaning, reducing mask wear to a minimum.
The LEEP process is also ideal for producing masks from Invar, an alloy renown for its uniquely low thermal coefficient of expansion that offers exceptionally good dimensional stability during the deposition process.
Both LEEP & LEEF processes are both efficient and cost effective for development, prototypes, small, medium and large-scale production applications.