激光隐形切割学习教案

1、会计学1激光隐形激光隐形(yn xn)切割切割第一页，共11页。What is Stealth Dicing?lStealth dicing （SD）An SD layer is formed below the surface of a workpiece by focusing a laser beam. Die separate by expanding the dicing tape.The SD process is a dry process and applies no force to the wafer. Short pulse laserFocusing lensWorkp

2、ieceSD layerStealth Dicing process flowStealth Dicing Die Breaking & Tape ExpandingForm an SD layerDFL7340STW210Die separationDicing tapeSiDicing tapeSi第1页/共11页第二页，共11页。lCompletely dry processSuitable for devices that are vulnerable to contamination and particles (e.g. MEMS).lNo mechanical load

3、applied to the waferSuitable for devices that are vulnerable to physical loads (e.g. Ultra-thin wafer / MEMS ).lNo debris during dicingGenerates no particles by processing below the surface of the waferNeeds no spinner cleaning after processingWafer with narrow streetsMEMSVulnerable to the waterSili

4、con devicesThin wafer with DAF SEM photographAdvantages of SD process - 1第2页/共11页第三页，共11页。After expanding Kerf width : 0 um Chipping : 0 um(A few micrometers of meander might occur during the separation process.)200m mmBefore expanding20m mmlExtremely thin kerfGreatly contributes to street reduction

5、 because the kerf width can be made extremely thinAdvantages of SD process - 2第3页/共11页第四页，共11页。- The number of passes 1- Feed speed 300 mm/s- Die size 55 mmSi: Thickness 100 m50m mm55mSD layer- The number of passes 7 *- Feed speed 300 mm/s- Die size 55 mm *One extra pass per street is needed to map

6、(measure + record) the workpiece surface 100m mmSi: Thickness 300 m40mSD layerlDicing without front or back side chippingBy controlling the position of the SD layer, the damage to both surfaces can be reduced Advantages of SD process - 3第4页/共11页第五页，共11页。T : Wafer thicknessW : Street width or clear w

7、idthTSiIncident pointLimitation of street width W 0.4xTWlLimitations of the SD processMetal in the streetlA laser can not penetrate the metal Films (e.g. SiO2, SiN, polyimide) lThey are permeable materials, but can beprocessedStreet width / thickness ratiolClear width is determined by the thickness

8、of the waferlLimitation of the expand processThick metallIt may be difficult to separate all of the metalDie size of 1mm square or lesslA separation process will be needed for small dieLimitations of SD process第5页/共11页第六页，共11页。SD solution of ShinAulShinAu will provide the special SD solution, which

9、is to be processed from backside of workpiece. If so, the SD process wont be limited by the street width & metal in the street. ShinAu SD process flowStealth Dicing Die Breaking, Tape expanding & TransferringForm an SD layerDFL7340STW210Die separationDicing tapeSiPattern sideSilicon sideTape

10、 mount from wafer back sideTape mount Silicon sidePattern side第6页/共11页第七页，共11页。Quality Control- Particles Required no particle on the pad-Kerf linearity Kerf offset distance less than 5um- No double die occurred during wafer breaking 第7页/共11页第八页，共11页。Concern & Discussion- Need bumping layout to check if any impact t