Browsing by Author "Bai, Dongshun"

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Process Development and Material Characteristics of TSV-less Interconnection Technology for FOWLP
(2017-01-01)
Shen, Wen-Wei
;
Lin, Yu-Min
;
Chang, Hsiang-Hung
;
Kuo, Tzu-Ying
;
Fu, Huan-Chun
Fan-out wafer-level-packaging (FO-WLP) technology is developed with the advantages of smaller package size, higher Input/Output (I/O) counts, lower cost, and better performance. In this study, the FO-WLP technology is applied to TSV-less inter-connection technology of 2.5D IC packaging and a novel RDL-first wafer level packaging is demonstrated. Firstly, a pre-coated laser release layer at the interface of RDL and carrier wafer is used for the separation of the reconfigured wafer and carrier wafer with laser de-bonding technology. Since release layer material is the key factor for de-bonding, these materials are evaluated to determine the quality. Test chips are flip-chip bonded onto a carrier wafer with 2 layers of RDL and passivation, following by wafer molding process. Wafers reveal a warp surface due to chemical material shrinkage and CTE mismatch during post mold curing. Warpage of molded wafer is needed to be optimized for equipment handling and the warpage characterization is collected to analyze by different processes. To examine the quality of the structure, electrical measurement is carried out and their respective results are presented.
Ultrathin Glass Wafer Lamination and Laser Debonding to Enable Glass Interposer Fabrication
(2015)
Shen, Wen-Wei
;
Chang, Hsiang-Hung
;
Wang, Jen-Chun
;
Ko, Cheng-Ta
;
Tsai, Leon
Interposer fabrication processes are applied in three-dimensional (3-D) integrated circuit (IC) integration to shorten the interconnection among different stacked chips and substrates. Because Si is a common material in semiconductor technology, Si interposers have been widely studied in many research activities. Compared with a Si wafer, glass substrates have the advantages of high resistivity, low dielectric constant, low insertion loss, adjustable coefficient of thermal expansion (CTE), and the possibility to use panel-size substrates as well as thin glass substrates (100 mu m) to avoid the costly thinning process for realization of low-cost 2.5-D ICs. Thus, glass interposer fabrication is studied thoroughly in this paper. Thin glass wafers have reduced mechanical stiffness. Therefore, handling and shipping thin glass wafers (<= 100 mu m) throughout the semiconductor fabrication and packaging assembly processes are critical. Temporary wafer bonding technology is used in this study to bond a thin glass wafer to a carrier to improve the rigidity. Vacuum lamination technology is used in this study as a bonding process to enhance the cost-effectiveness. After processing, the carrier is removed by laser debonding. The thin glass wafer with structures on both sides does not need to undergo a glass thinning process and saves a lot of cost compared to the traditional glass or Si interposer processes. Thin 300-mm glass wafers 100 mu m thick are evaluated as: (a) blank thin glass wafers and (b) thin glass wafers with through-glass vias (TGVs) 30 mu m in diameter. A UV laser with a wavelength of 308 nm, which has the benefit of less impact to the device, was adopted to laser debonding. This method also has several benefits such as high throughput, low temperature, zero-force debonding, and possible selective laser debonding. Adhesive and release layers are key enabling materials for thin glass handling. In addition, the use of a laminator for temporary bonding and laser debonding are included in this study. Based on the excellent fabrication, the thin glass interposer has great potential to be applied in 2.5-D integration applications.