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CS Product Development

CS Product Development. CS Product Team MAY, 2007. Introduction. It is aimed to optimize sawing conditions and provide better singulation quality in smearing, burr size and chipping of TICP 7x7 units In the presentation, singulation quality and conditions would be discussed

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CS Product Development

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  1. CS Product Development CS Product Team MAY, 2007

  2. Introduction • It is aimed to optimize sawing conditions and provide better singulation quality in smearing, burr size and chipping of TICP 7x7 units • In the presentation, singulation quality and conditions would be discussed • Presentation Outline • Workpiece Conditions Comparison • Comparison of singulated QFN • Sawing method selection • Cooling method • Blade selection • Machine parameter: Feed rate and spindle speed • Results of selected sawing method • Conclusions

  3. QFN Conditions • Combination of workpiece conditions, blade conditions and sawing parameter will finally alter singulation quality • Workpiece • Materials of lead-frame and molding composite • Blade • Grit size, density and binding materials • Sawing parameters • Feed rate, spindle speed and cooling method

  4. TICP 1088-080-31512 TICP 1088-080-29612 3x3 QFN (Others) QFN Conditions – material properties • Lead-frame materials and properties * Olin copper alloy guide, www.olinbrass.com

  5. QFN Conditions – burr • For a softer material, it is more favor for plastic bending and shearing deformation plane contributes to the burr formation Top view 20mm/s, 25kRPM TICP 1088-080-31512 Softer lead material 20mm/s, 25kRPM Burr of TICP 7x7 1088-080-31512 at 20mm/s 30kRPM TICP 1088-080-26912 Harder lead material

  6. TICP 7x7 1088-080-31512 TICP 7x7 1088-080-26912 7x7 unit (Others) QFN Conditions – chipping • Mold composite Larger particle size More filler particles can reduce workpiece warpage but enhance chipping Smoother surface

  7. Comparison of Singulated QFN • For the same Resin bond dicing blade is applied, smearing (lead pattern) and burr size is different TICP 7x7 1088-080-31512 3x3 QFN (Others) Feed: 20mm/s Spindle: 30kRPM Feed: 50mm/s Spindle: 25kRPM

  8. Sawing Method Selection • History: • Cutting quality for Taiwan tested samples • lead spacing < 4 mil, burr size > 3 mil was recorded • Singulation quality optimization tests were carried out: • Sawing Conditions • Machine: DAD 6340 • Blade: Synthetic diamond resin blades • Holding: Saw Jig • Drive-in: 0.2mm • Coolant: Room temperature water • Focused areas for quality optimization tests: • Coolant jetting method • Blade selection • Cutting parameter tuning

  9. Sawing Method Selection • Coolant jetting method • For proper coolant jetting height • It can be shown that smearing effect was improved • Blade selection • Resin bond dicing blades with different grit size were applied

  10. Larger Grit Size 20mm/s 30kRPM Smaller Grit Size 20mm/s 30kRPM Sawing Method Selection – Blade Selection • Performance of dicing with different grit size • For the smaller grit size • Burr size is smaller, about 2 mils or smaller is achieved

  11. Better performance parameter range Within Specification Sawing Method Selection - Smearing • Several experiments were carried out, sawn quality was recorded with respect to the feed rate and spindle speed Lead spacing is reduced when feed rate and spindle speed

  12. Sawing Method Selection - Smearing Spindle Speed 10mm/s 30kRPM 10mm/s 20kRPM 10mm/s 25kRPM Feed Rate 20mm/s 30kRPM 20mm/s 25kRPM 20mm/s 25kRPM 30mm/s 20kRPM 30mm/s 25kRPM 30mm/s 30kRPM

  13. Better performance parameter range Within Specification Sawing Method Selection - Burr • Burr size would reduced at certain combination of spindle and feed rate

  14. Sawing Method Selection - Burr Spindle Speed Feed Rate 10mm/s 20kRPM 10mm/s 25kRPM 10mm/s 30kRPM 20mm/s 20kRPM 20mm/s 25kRPM 20mm/s 30kRPM 30mm/s 20kRPM 30mm/s 25kRPM 30mm/s 30kRPM

  15. Within Specification Sawing Method Selection - Chipping • Chipping is exist and generally larger than 2 mil • Corner and edge chipping was discovered • For some cases, large corner chipping happened • Further arrangement is necessary for solving this problem

  16. Latest Sample Chipping Jig Sawing Sample Tested in Taiwan Chipping Tape Sawing Sample Chipping Sawing Method Selection - Chipping • Moreover, chipping is also happened for tape sawn units and the previously samples testing in Taiwan

  17. Results of Sawing Method Selection • For TICP 7x7 5up singulation process • 20mm/s and 25kRPM is selected • Smaller burr size and more stable burr pattern with respect to other sawing conditions • Lead spacing within specification and more stable in smearing pattern when compare with other sawing conditions • Further study in chipping is necessary

  18. Conclusions • Different surface coating and lead-frame materials in TICP 7x7 workpiece • Morphology of molding compound surface is captured • Allowable cutting method selection based on • Cooling method • Blade selection • Cutting parameter tuning • 20mm/s 25kRPM is selected • Smearing and burr size within specifications • Edge and corner chipping is slightly out of specifications 2 mils

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