Wafer stencils in IC manufacturing
The stencil sheet plays a central role in wafer production. The stencil is used to apply the solder paste to the wafer during printing. Therefore, the process is one of the first and also most important steps in the entire production process. Mistakes during printing are one of the main causes of unreliable or defective solder joints on electronic assemblies. Wafer stencils are characterized in particular by very small openings in combination with a high packing density - several hundred thousand apertures per stencil are not uncommon in this case. Consequently, reliability, accuracy and quality of the stencil are extremely important for the manufacturing process - especially with regard to the high costs incurred per wafer for production.
Manufacturing wafer stencils with laser systems
Using the laser, the finest apertures, most complex and densely packed designs as well as all common material thicknesses of wafer stencils can be processed. The laser fully meets all stencil requirements. Laser systems - especially from LPKF - offer the highest precision and accuracy, and can reliably and reproducibly implement the smallest contours. The laser also excels in terms of performance, because LPKF laser systems can easily produce several ten thousand apertures per hour.
Benefits of producing wafer stencil with laser systems
In terms of the process, the laser offers a further advantage: due to its conical, i.e. tapering towards the substrate, the laser can also incorporate corresponding conical apertures into the stencil. This type of aperture offers significantly optimized paste release behavior and consequently better control of the paste during printing.