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Suss implements breakthrough contact printing technology
Keywords Karl Suss, Motorola, Lithography
Karl Suss announced that it has finalized an agreement with Motorola Labs to offer proprietary new mask protection technology (MPT) to its worldwide client base. The immediate customer benefit of this new technology includes significantly increased device yields through extreme reduction of particle contamination in hard and vacuum contact lithography. This patent-pending technology allows a large number of contacts between mask and wafer without the normal mask wear or damage. The impressive results of this new process allow SUSS to immediately provide its customers with a dramatically increased yield compared to conventional contact printing. This is accomplished with a resolution capability similar to projection lithography techniques.
Vacuum contact prints made with the new process at the 0.75 micrometer resolution level show no significant degradation after 200 wafers are processed. There is no remarkable particle contamination of the mask, enabling excellent contact to be maintained between mask and wafer, even after a large number of subsequent prints. Contact lithography has always provided very high resolution, but the drawback has been particle contamination of the mask, leading to lower resolution and reduced yield with an increasing number of prints. The new technology eliminates these drawbacks to a large extent and can therefore be considered a significant process breakthrough.
SUSS considers the main markets for this novel technology to be the communication market (GaAs devices, SAW filters, optoelectronics), as well as, MEMS/MST applications where contact printing is already widely used. The new technology will make the transition from laboratory devices to production much easier, as the same printing method can be used for both.
For solder bumping where feature sizes are 50-100 µm and proximity gaps of the same size are typical, the new MPT method will not improve yield, as mask and wafer do not risk contact. However, in gold bumping where gaps are sometimes reduced to 30 µm in order to pattern 10 µm features, MPT is expected to help maintain the high process yield known from larger gaps.
SUSS plans to integrate MPT into its existing product line and license the new process to customers immediately.
For further information, visit www.suss.com