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image/svg+xml Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Closed Access logo, derived from PLoS Open Access logo. This version with transparent background. http://commons.wikimedia.org/wiki/File:Closed_Access_logo_transparent.svg Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao https://doi.org/10.1...arrow_drop_down
image/svg+xml Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Closed Access logo, derived from PLoS Open Access logo. This version with transparent background. http://commons.wikimedia.org/wiki/File:Closed_Access_logo_transparent.svg Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao
https://doi.org/10.1109/ectc.2...
Article . 2019 . Peer-reviewed
License: IEEE Copyright
Data sources: Crossref
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Process Induced Wafer Warpage Optimization for Multi-chip Integration on Wafer Level Molded Wafer

Authors: Chen-Yu Huang; Daniel Ng; Hung-Ho Lee; Vito Lin; Chang-Fu Lin; C. Key Chung;

Process Induced Wafer Warpage Optimization for Multi-chip Integration on Wafer Level Molded Wafer

Abstract

In this paper, the demonstration of test vehicle by two kinds of process flows noted as "C4 first" and "C4 last", which integrate chips on mold-based, Cu via wafer with glass carriers, are presented. Their warpage behavior during wafer-form integration will be experimentally and numerically evaluated, and also compared with wafer warpages of 2.5D assembly which applied Si interposer with TSV (through Si via). The C4-first flow is to attaching chips on wafers where the C4 bumps have been completed between mold layer and glass carrier. This flow is similar to 2.5D manufacturing process that the Si interposer was temporarily bonded on a carrier which can suppress the interposer warpage variation during reflow process. The temporary glue is required to protect the C4 bumps during chip on wafer procedures. In regarding to the cycle time and cost, the flow to complete C4 after chips attaching will be further studied. The processed induced u-bump (micro-bump) and u-pad (micro-pad) shift post jointing are observed to be larger than that in 2.5D flow. In the manufacturing process of molded wafer, the high CTE glass carriers are used to reduce CTE mismatch between molding compound and carrier. The significant wafer warpage changing from concave to convex shape was observed after chips attaching on the wafer. And the warpage will be further increased after underfilling and molding processes. To well predict and address the warpage trend, the finite element analyses are carried out to understand the process-induced warpage behaviors, and thus to select better material and process parameter. The key parameters affecting wafer warpages like material properties of molding compound, glass carrier and top-mold thickness are determined by finite element simulation. In light of the handing procedure of wafer form assembling equipment, the preferred wafer warpage shape is determined by experimental results. Finally, the test vehicle have been assembled with substrate as well. The chip module warpage in 2.5D structure is about double than that with molding interposer at 230°C and reversed direction in a convex shape, which is different from molding chip module.

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
3
Average
Average
Average
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