Lecture32

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Lecture32

  1. 1. Design and Implementation of VLSI Systems (EN1600) Lecture 32: Pad Frame Design and PackagingS. Reda EN1600 SP’08
  2. 2. Packaging choicesS. Reda EN1600 SP’08
  3. 3. Chip-to-Package Bonding • Traditionally, chip is surrounded by pad frame – Metal pads on 100 – 200 mm pitch – Gold bond wires attach pads to package – Lead frame distributes signals in package – Metal heat spreader helps with coolingS. Reda EN1600 SP’08
  4. 4. Pad frame So far we looked at core design This lecture we look at pad frame designS. Reda EN1600 SP’08
  5. 5. MOSIS AMI 0.5u Tiny Chip frameTanner reserves one ofthe left pins for VDD andone of right pins for GNDS. Reda EN1600 SP’08
  6. 6. Generic pad layoutS. Reda EN1600 SP’08
  7. 7. ESD protection • Static electricity builds up on your body – Shock delivered to a chip can fry thin gates – Must dissipate this energy in protection circuits before it reaches the gates Diode clamps • ESD protection circuits R PAD – Current limiting resistor Current Thin – Diode clamps limiting resistor gate oxides – Diodes must be large to sustain significant current • Example: Consider charge on human body discharged at a rate (current) = 10 uA for 1us at to a capacitor C=0.025pF → Voltage buildup = 400V destroys the transistor gateS. Reda EN1600 SP’08
  8. 8. Example 1: PADARef offers basic ESD protection metal 2 distributes VDD metal 1 distributes signal D Simplest padS. Reda EN1600 SP’08
  9. 9. Example 2: PADOUT Pad has internal bufferS. Reda EN1600 SP’08
  10. 10. Automatic generation of pad frame in Tanner Tools 1.Add the pad library to your S-Edit design 2.Modify your design to use the pads. Naming convention: if you name nets getting into a pad as PAD_L1 places the pad at the first left location in the pad frame.S. Reda EN1600 SP’08
  11. 11. Automatic generation of pad frame in Tanner Tools 3. In L-Edit, change SPR setup to In padframe setup, Change the layout size to 1.5mm x 1.5mm Use the new library with the pads and press initialize setup In padroute setup, make sureS. Reda EN1600 SP’08 you have these design rules
  12. 12. Automatic generation of pad frame in Tanner Tools Finally run the place and route and make sure to mark “PadFrame generation” and “Pad route” You might get a few DRC violations in metal2 that you would need to fix yourselfS. Reda EN1600 SP’08

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