DEK has developed an equipment and tooling package that coats wafers with ultra-thin die attach materials down to 25 microns in thickness with tolerances of +/- 7 microns using a printing process.
 
Using a Micron-class Galaxy mass imaging system, an ultra-flat pallet, a die attach stencil or screen and a specially designed squeegee, the backside wafer coating process enables ultra-thin, precise deposits of die attach adhesive at high speed with an accurate, flexible screen printing platform. Bondline thickness can be controlled to customer specifications, fillet control is consistent with that of traditional film products without the 20-30% higher cost, UPH is higher than that of dispensing and the coated wafer can be pre-manufactured and stored until required. Ultra-flat pallet provides stability and uniformity required to process wafers as thin as 100 microns and up to 300 mm in diameter; specially engineered squeegee delicately applies the adhesive paste to the backside of the wafer.
 
Other advantages include the elimination of the fillet and subsequent reduction of paste adhesive volume (potentially by a factor of ten on die less than 0.5 x 0.5 mm), improved inventory control by concentrating the application of wet adhesive in the facility’s dedicated print area and streamlining the supply chain by requiring only one paste formulation for various process needs as opposed to the multiple thicknesses and widths necessary with films. Can be used for all wafer-level coating processes including epoxy and wafer-level protective backside coatings as well.
 
Is run on a flexible mass imaging platform, can also re-deployed for other packaging applications such as wafer bumping, DirEKt Ball Placement, thermal interface material (TIM) processing and encapsulation.
 

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