Effect Of Nanosecond Laser Dicing On Ultrathin Silicon Die With Copper Stabilization Layer
| dc.contributor.author | Marks, Michael Raj | |
| dc.date.accessioned | 2017-01-17T01:32:10Z | |
| dc.date.available | 2017-01-17T01:32:10Z | |
| dc.date.issued | 2016-08 | |
| dc.description.abstract | Ultrathin dies require a Cu stabilization layer, which is essentially a backside Cu layer, to prevent warpage and cracks during solder die attach and wire bonding. The dicing of Si wafers with a backside Cu layer is challenging. Mechanical blade dicing through the Cu layer causes blade clogging and damage, which eventually results in severe die chipping and cracks. Plasma dicing is costly as it requires additional photolithography and etching steps. Laser dicing is promising and is currently used to singulate thin Si wafers. However, there is no reported work on its application for dicing ultrathin wafers with a backside Cu layer. In this work, the feasibility of fabricating 20 μm ultrathin Si wafers with 5-20 μm frontside Cu and 10-30 μm backside Cu has been shown. The thicknesses of the metal and Si layers are within 10% of the process target. No interfacial delamination was detected. The feasibility of dicing through 20 μm ultrathin Si wafers with 10-30 μm backside Cu with nanosecond UV laser have also been demonstrated. The effect of nanosecond laser dicing on the die sidewall strength was evaluated with the three-point bend (3PB) test. Analytical and experimental results have shown that the Cu and AlCu layers have gone into plastic condition during the 3PB test. Comparison of the 3PB fracture loads indicates that the Si backside strength is higher than the Si frontside strength. Fractographic analysis has confirmed that the fracture initiation sites during the 3PB tests are at the die sidewall. The die sidewall defect morphologies, structures, and elemental compositions have been characterized in detail by transmission electron microscopy, and their effect on mechanical strength is discussed. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/3459 | |
| dc.subject | Effect Of Nanosecond Laser Dicing | en_US |
| dc.subject | On Ultrathin Silicon Die. | en_US |
| dc.title | Effect Of Nanosecond Laser Dicing On Ultrathin Silicon Die With Copper Stabilization Layer | en_US |
| dc.type | Thesis | en_US |
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