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Mask Design for Molds. Mask Design for Molds. Spin SU8(negative resist) on Si wafers Expose using mask (channel mask and interconnect mask) Develop both molds. Mask Design for Molds. From molds: spin on PDMS less than the vertical dimension From channel mold: make two layers
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Mask Design for Molds • Spin SU8(negative resist) on Si wafers • Expose using mask (channel mask and interconnect mask) • Develop both molds
Mask Design for Molds • From molds: spin on PDMS less than the vertical dimension • From channel mold: make two layers • From interconnect mold: make one layer • Stack three layers in channel, interconnect, channel (90o rotation from first channel layer) order I/O Bottom layer I/O Middle layer Top layer
Mask Dimensions • For initial preliminary fabrication larger dimensions are better • Approximate channel and interconnect width 150 mm • Channel length 45mm • Reservoirs 300mm diameter (total length channel and reservoir 45.6mm • Distance between channels 300mm • Mold feature height 300mm
Modified Mask Design for Molds • Spin SU8(negative resist) on Si wafers • Expose using mask (channel mask, interconnect mask, and top mask) • Develop all three molds
Modified Mask Design for Molds • From molds: spin on PDMS less than the vertical dimension for all four layers • From channel mold: make two layers • From interconnect mold: make one layer • From top mold: make one layer • Stack all four layers in channel, interconnect, channel (90o rotation from first channel layer), and top order
Modified Mask Dimensions • Coordinate of the reservoirs (mm): • (20.0,20.9), (5.6,12.8), (12.8,5.6) in all four quadrants • Coordinates of the channel intersections (mm): • (0,0),(0,7.2),(7.2,0),(3.6,3.6) in all four quadrants • Channel Width: 150 mm • Reservoir Diameter: ?
Modified Mask Considerations • How many of the nine channel intersections should be used as interconnects between layers (3 or 9) • Should the first channel layer be open or closed on the bottom surface (PDMS or Pyrex bottom) • Should a top layer channel be used or should the top remain open • Should the size of the reservoir throughputs be the same size or smaller then the reservoirs