元件吃锡效果与PCB Layout关系.ppt

1、PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,1,元件吃锡效果与PCB Layout关系,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,2,進 板 方 向,GOOD,1. TWO SMD TOO CLOSE 2. SMT 本體易產生陰影效應,8JES326S.0A3 PCB,進板方向,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,3,光學點反黑範圍太小 此光學點可以不用LAYOUT,8JES326S.0A3 PCB,光學點太小,PHOTO BY QC/ WONDE

2、R NOTED BY MED/ STEVEN KUO,4,光學點為土黃色, 黑色佳,8JES326S.0A3 PCB,光學點顏色,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,5,陰影效應,8JES326S.0A3 PCB,陰影效應,進板方向 LAYOUT請註明進板方向,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,6,GOOD(BIG PAD),8JES326S.0A3 PCB,BIG PAD,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,7,太密易造成短路 沒

3、拖錫點LAYOUT,8JES326S.0A3 PCB,CONNECTER SHORT,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,8,8JES326S.0A3 PCB,正板零件容易被破壞或掉件 熱氣會由貫穿孔往上衝,PTH & PAD TOO CLOSE,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,9,8JES326S.0A3 PCB,加白點有助減少short缺點, 最好加一白線,加白漆防焊(文字印刷),PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,10,8J

4、ES326S.0A3 PCB,Phone jack 和SMD太近 且SMT component 太近 易短路現象發生,進板方向,PAD & PAD TOO CLOSE,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,11,8JES326S.0A3 PCB,光學點離pad太近(BGA會打不準),光學點& PAD TOO CLOSE,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,12,S1024B.5A18E PCB,節省工時 可使用吃錫螺絲,吃錫螺絲,PHOTO BY QC/ WONDER NOTED BY M

5、ED/ STEVEN KUO,13,S1024B.5A18E PCB,增加拖錫點 避免短路發生,進板方向 LAYOUT請註明進板方向,增加拖錫點防止短路,沒有作用的拖錫點,增加拖錫點 避免短路發生,沒有作用的拖錫點,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,14,S1024B.5A18E PCB,SOLDER SIDE IC 容易短路 IC 最好LAY在正板 或以45LAYOUT較不易造成PIN 腳短路 否則需用昂貴治具COVER,IC ON SOLDER SIDE LAYOUT DIRECTION,PHOTO BY QC/ WONDER NOT

6、ED BY MED/ STEVEN KUO,15,S1024B.5A18E PCB,不要利用螺絲孔接地,PAD & SCREW HOLE GROUNDING,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,16,S1024B.5A18E PCB,VIA hole 綠漆應蓋solder side 避免錫珠掉在VIA HOLE造成零件問題(翹件、空焊),SOLDER MASK ON SOLDER SIDE ONLY,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,17,S1024B.5A18E PCB,以馬賽克LA

7、YOUT方式較好(熱平衡),DUMMY PAD,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,18,防焊,防止PTH拉錫,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,19,TOO CLOSE 容易SHORT,COMPONENT TOO CLOSE,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,20,電容容易FAIL PTH 熱氣會沖上來,吃錫不好 銅箔太大, 散熱太快,SOLDER NOT ENOUGH,PHOTO BY QC/ WONDER NOTED BY

8、MED/ STEVEN KUO,21,容易SHORT 吃錫後外觀不良,?,EASY SHORT,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,22,陰影效應,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,23,拖錫棒 避免SOCKET SHORT,拖錫棒,進板方向 LAYOUT請註明進板方向,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,24,避免CONNECTOR SHORT 假的pad 拖錫用,進板方向 LAYOUT請註明進板方向,拖錫棒設計方向,PHOTO

9、BY QC/ WONDER NOTED BY MED/ STEVEN KUO,25,進板方向,Layout 沒考量進板方向, 假pad 放錯邊,SOLDER DIRECTION,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,26,此處 淚滴(TEAR DROP)設計較好, 狗骨頭(DOG BONS)不好,DOG BONS,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,27,不好的接地,SCREW HOLE & SMD,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,

10、28,good,No good,SCREW HOLE,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,29,不好的layout 吃錫易不足 散熱快,good,HEAT TRANSFER,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,30,測試點layout,TEST POINT,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,31,過Wave solder時電解質電容容易遭熱氣上沖而Fail,電容易被熱氣沖壞,PHOTO BY QC/ WONDER NOTED BY

11、MED/ STEVEN KUO,32,BGA LAYOUT: DOG BONS BETTER THAN TEAR DROP,Dog bone Vs Tear drop,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,33,背板 拖錫棒,拖錫,進板方向,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,34,測試點 LAYOUT 方式,TEST POINT,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,35,WAVE SOLDER PROFILE,PHOTO BY QC/

12、 WONDER NOTED BY MED/ STEVEN KUO,36,Assembly,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,37,SMT Process Flow,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,38,SMT Process Flow,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,39,SMT Process Flow,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,40,SMT Process

13、Flow,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,41,SMT Process Flow,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,42,Wave soldering Profile,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,43,Machine setup and process characteristics,Board/wave contact length Board dwell time in solder wave(s) Board im

14、mersion depth in waves(s) Conveyor speed Converyor to wave orientation Preheat temperature slope Max preheat temperature Temperature spike at the wave(s) Solder temperature in the wave(s) Time above liquidus,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,44,IR Reflow Solder profile,PHOTO BY QC/ WONDER

15、 NOTED BY MED/ STEVEN KUO,45,Vapor Phase reflow solder Profile,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,46,Preheating,To reduce thermal shock to PWB from solder wave To active the flux by heating it. To dry the flux which would otherwise boil during soldering, causing solder balls. To prevent th

16、e board warping during soldering.,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,47,Stencil,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,48,Key point of Process (1),Conveyor speed Boards pollution Dwell time Solder temperature Solder pot contamination Type of flux Flux contamination Flux foamed uneven

17、 Preheater temperature Solder wave uneven,Components contamination Boards oxided Boards re-run Defective fixture Flux Blow-off (air knife) excessive Flux not making contract Boards not seated right Flux foamed low Flux specific gravity,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,49,Key point of Pro

18、cess (2),Incorrect flux bubble size Improper board handling Solder wave turbulent Flux no longer active Pallet design Defective mask materials Internal planes (Multilayer) Large planes on solder side,Pallet too hot Type of coating Board wrapped Flux Blow-off (air knife) not on Incorrect weight place

19、ment Misregistration of mask Base material (epoxy resin),PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,50,Defect and Counterdefect Force,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,51,Drawbridge,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,52,Conveyor angle,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN K

20、UO,53,Solder joint fail,Residual plating chemicals Incomplete cleaning after plating Surface contamination Surface oxidation,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,54,SOLDER BUMPING: VOIDING,1. solvents in the flux system unable to diffuse through the molten solder during reflow 2. alloy shrin

21、kage on cooling 3. joint shape - the path of escape for vapors can be difficult and lead to entrapped gases 4. improper or non-optimized heating profile 5. plating or solder mask related issues (outgassing, inadequate cleaning, etc.) 6. type of solder paste and powder size used,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,55,印刷電路板,方向不當 尺寸設計不良 未置於定位 有異物或受污染 受重壓 寬幅不當 保護層處理不當 印刷電路板或零件過期及儲存不當,重量分佈不當 氧化 破損 插件面設計不良 載重過多 變形 焊錫面設計不良 多層板內電路設計不良,PHOTO BY QC/ WONDER NOTED BY MED/ STEVEN KUO,56,印刷電路板,印刷油墨不良 過量印刷油墨 印刷油墨未稱位 抗焊印刷