双面Reflow 改单面Reflow双面Reflow 改单面Reflow.ppt

Single Reflow Process flow Benefit Single reflow process helps on solder joint reliability due to less thermal impact and IMC growth comparing double reflow process Benefit hole fill due to less OSP performance degrading Minimized process control station Minimized manual handling Cost saving to 60KUSD per line per year Feasibility Assessment –Station by Station Bottom side screen printing ---- same as normal Bottom side pickplace– same as normal PCB flip--- add automatic PCB inverter to eliminate manual handling Top side printing--- With supporting fixture, pressure to PCB during printing was distributed to fixture. No vibration at this station. Top side Pickplace--- 2 N placement force is negligible Reflow soldering--- tackiness from solder paste before melting and surface tension during melting prevent component from dropping. Transportation--- Not to touch PCB anytime prior to soldering. Impact to PCB during transportation can be resolved by tackiness from solder paste. Above of all, there is feasibility to run single reflow process for double side assembly. Feasibility Assessment –Simulation Qualification Run Root cause analysis for component missing Component weight acts as accessary of tombstone to increase the imbalance level of wetting force during reflow in the single side reflow process, there is chance for component dropping in the process of forming a tombstone if there is a vibration or shaking N2 used here with O2 ppm at very low level 800PPm increase the opportunity of tombstone significantly comparing to air reflow process Qualification Run Summary Base on the qualification run result, 17DPMO at bottom side SMT bring us the confidence for Dell fleming project. Relatively we can achieve 99.7% first pass yield. Single side reflow process is qualified and to be de implemented. * Global Operations - China Engineering * Global Operations - China Engineering * Global Operations - China Engineering * Global Operations - China Engineering Des