Warpage Characterization of Molded Wafer for Fan-Out Wafer-Level Packaging

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Hsien-Chie Cheng ◽  
Yan-Cheng Liu
Keyword(s):  
Measurement Data ◽  
Mechanical Analysis ◽  
Volumetric Shrinkage ◽  
Heat Of Reaction ◽  
Wafer Level ◽  
Molding Process ◽  
Scanning Calorimetry ◽  
Molding Compound ◽  
Wafer Level Packaging

Abstract This study presents a comprehensive assessment of the process-induced warpage of molded wafer for chip-first, face-down fan-out wafer-level packaging (FOWLP) during the fan-out fabrication process. A process-dependent simulation methodology is introduced, which integrates nonlinear finite element (FE) analysis and element death-birth technique. The effects of the cure-dependent volumetric shrinkage, geometric nonlinearity, and gravity loading on the process-induced warpage are examined. The study starts from experimental characterization of the temperature-dependent material properties of the applied liquid type epoxy molding compound (EMC) system through dynamic mechanical analysis (DMA) and thermal mechanical analysis. Furthermore, its cure state (heat of reaction and degree of cure (DOC)) during the compression molding process (CMP) is measured by differential scanning calorimetry (DSC) tests. Besides, the cure dependent-volumetric (chemical) shrinkages of the EMC system after the in-mold cure (IMC) and postmold cure (PMC) are experimentally determined by which the volumetric shrinkage at the gelation point is predicted through a linear extrapolation approach. To demonstrate the effectiveness of the proposed theoretical model, the prediction results are compared against the inline warpage measurement data. One possible cause of the asymmetric/nonaxisymmetric warpage is also addressed. Finally, the influences of some geometric dimensions on the warpage of the molded wafer are identified through parametric analysis.

Mechanical Analyses of Advanced Multi-Chip Embedded Wafer Level Packages

2013 ◽  
Vol 740 ◽  
pp. 289-294
Author(s):  
Siow Ling Ho ◽  
Lin Bu ◽  
Dexter Velez Sorono ◽  
Ser Choong Chong ◽  
Tai Chong Chai ◽  
...  
Keyword(s):  
Cycling Performance ◽  
Market Demand ◽  
Wafer Level ◽  
Molding Process ◽  
Molding Compound ◽  
Mechanical Effects ◽  
Wafer Level Packaging ◽  
Attractive Option ◽  
Small Form Factor ◽  
Improved Accuracy

ncreasing functionality accompanied with device miniaturization in microelectronics has led to increased market demand for packages with small form factor. Over the years, embedded wafer level packaging (EWLP) has become an attractive option since it allows a reduction in package size and height. In the EWLP approach, the singulated dies are embedded within the molding compound through the wafer level compression molding process. For this study, critical mechanical challenges such as die shift and thermal cycling performance of a multi-chip embedded wafer level package (MCEWLP) are addressed through numerical modeling. For improved accuracy in die shift predictions, both mechanical effects and fluidic effects need to be taken into account. Mechanical effects account for around 75% of the die shift while fluidic effect contributes to the remaining 25%. It is shown that reducing the die size and the inclusion of UBM as a buffer layer can effectively increase the fatigue life of the packages.

Light-cured dental composites characterization by Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 428-429
Author(s):  
B. M. Culbertson ◽  
M. L. Devinev ◽  
E. C. Kao
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Service Performance ◽  
Dental Composite ◽  
Dental Composites ◽  
Neat Resin ◽  
Scanning Calorimetry ◽  
Research Meeting ◽  
Formulation Variables

The service performance of current dental composite materials, such as anterior and posterior restoratives and/or veneer cements, needs to be improved. As part of a comprehensive effort to find ways to improve such materials, we have launched a broad spectrum study of the physicochemical and mechanical properties of photopolymerizable or visible light cured (VLC) dental composites. The commercially available VLC materials being studied are shown in Table 1. A generic or neat resin VLC system is also being characterized by SEM and TEM, to more fully understand formulation variables and their effects on properties.At a recent dental research meeting, we reported on the differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) characterization of the materials in Table 1. It was shown by DSC and DMA that the materials are substantially undercured by commonly used VLC techniques. Post curing in an oral cavity or a dry environment at 37 to 50°C for 7 or more hours substantially enhances the cure of the materials.

scholarly journals Preparation and Characterization of Talc Filled Thermoplastic Polyurethane/Polypropylene Blends

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Emi Govorčin Bajsić ◽  
Vesna Rek ◽  
Ivana Ćosić
Keyword(s):  
Thermal Properties ◽  
Thermoplastic Polyurethane ◽  
Mechanical Analysis ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Polypropylene Blends ◽  
Pp Blends ◽  
The Degree Of Crystallinity ◽  
Better Than

The effect of the addition of talc on the morphology and thermal properties of blends of thermoplastic polyurethane (TPU) and polypropylene (PP) was investigated. The blends of TPU and PP are incompatible because of large differences in polarities between the nonpolar crystalline PP and polar TPU and high interfacial tensions. The interaction between TPU and PP can be improved by using talc as reinforcing filler. The morphology was observed by means of scanning electron microscopy (SEM). The thermal properties of the neat polymers and unfilled and talc filled TPU/PP blends were studied by using dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The addition of talc in TPU/PP blends improved miscibility in all investigated TPU/T/PP blends. The DSC results for talc filled TPU/PP blends show that the degree of crystallinity increased, which is due to the nucleating effect induced by talc particles. The reason for the increased storage modulus of blends with the incorporation of talc is due to the improved interface between polymers and filler. According to TGA results, the addition of talc enhanced thermal stability. The homogeneity of the talc filled TPU/PP blends is better than unfilled TPU/PP blends.

Enhancing the Thermal and Mechanical Characteristics of Polyvinyl Alcohol (PVA)-Hemp Protein Particles (HPP) Composites

2021 ◽  
Vol 36 (2) ◽  
pp. 137-143
Author(s):  
S. A. Awad
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Composite Films ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Solution Casting Method ◽  
Protein Particles

Abstract This paper aims to describe the thermal, mechanical, and surface properties of a PVA/HPP blend whereby the film was prepared using a solution casting method. The improvements in thermal and mechanical properties of HPP-based PVA composites were investigated. The characterization of pure PVA and PVA composite films included tensile tests, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results of TGA and DSC indicated that the addition of HPP increased the thermal decomposition temperature of the composites. Mechanical properties are significantly improved in PVA/HPP composites. The thermal stability of the PVA composite increased with the increase of HPP filler content. The tensile strength increased from 15.74 ± 0.72 MPa to 27.54 ± 0.45 MPa and the Young’s modulus increased from 282.51 ± 20.56 MPa to 988.69 ± 42.64 MPa for the 12 wt% HPP doped sample. Dynamic mechanical analysis (DMA) revealed that at elevated temperatures, enhanced mechanical properties because of the presence of HPP was even more noticeable. Morphological observations displayed no signs of agglomeration of HPP fillers even in composites with high HPP loading.

Fan-Out Wafer-Level Packaging (FOWLP) of Large Chip with Multiple Redistribution Layers (RDLs)

2017 ◽  
Vol 14 (4) ◽  
pp. 123-131 ◽  
Author(s):  
John Lau ◽  
Ming Li ◽  
Nelson Fan ◽  
Eric Kuah ◽  
Zhang Li ◽  
...  
Keyword(s):  
Thin Layer ◽  
Glass Wafer ◽  
Front Side ◽  
Wafer Level ◽  
Molding Compound ◽  
The Third ◽  
Wafer Level Packaging ◽  
Die Attach ◽  
Solder Balls ◽  
Test Package

This study is for fan-out wafer-level packaging with chip-first (die face-up) formation. Chips with Cu contact-pads on the front side and a die attach film on the backside are picked and placed face-up on a temporary-glass-wafer carrier with a thin layer of light-to-heat conversion material. It is followed by compression molding with an epoxy molding compound (EMC) and a post-mold cure on the reconstituted wafer carrier and then backgrinding the molded EMC to expose the Cu contact-pads of the chips. The next step is to build up the redistribution layers (RDLs) from the Cu contact-pads and then mount the solder balls. This is followed by the debonding of the carrier with a laser and then the dicing of the whole reconstituted wafer into individual packages. A 300-mm reconstituted wafer with a package/die ratio = 1.8 and a die-top EMC cap = 100 μm has also been fabricated (a total of 325 test packages on the reconstituted wafer). This test package has three RDLs; the line width/spacing of the first RDL is 5 μm/5 μm, of the second RDL is 10 μm/10 μm, and of the third RDL is 15 μm/15 μm. The dielectric layer of the RDLs is fabricated with a photosensitive polyimide and the conductor layer of the RDLs is fabricated by electrochemical Cu deposition (ECD).

Development of G-Helix Structure as Off-Chip Interconnect

2004 ◽  
Vol 126 (2) ◽  
pp. 237-246 ◽  
Author(s):  
Qi Zhu ◽  
Lunyu Ma ◽  
Suresh K. Sitaraman
Keyword(s):  
Mechanical Performance ◽  
Coefficient Of Thermal Expansion ◽  
Mechanical Analysis ◽  
Organic Substrate ◽  
Electrical Performance ◽  
Wafer Level ◽  
Wafer Level Packaging ◽  
Package Weight ◽  
Mechanical Compliance ◽  
Cte Mismatch

Microsystem packages continue to demand lower cost, higher reliability, better performance and smaller size. Compliant wafer-level interconnects show great potential for next-generation packaging. G-Helix, an electroplated compliant wafer-level chip-to-substrate interconnect can facilitate wafer-level probing as well as wafer-level packaging without the need for an underfill. The fabrication of the G-Helix interconnect is similar to conventional IC fabrication process and is based on electroplating and photolithography. G-Helix interconnect has good mechanical compliance in the three orthogonal directions and can accommodate the differential displacement induced by the coefficient of thermal expansion (CTE) mismatch between the silicon die and the organic substrate. In this paper, we report the wafer-level fabrication of an area-arrayed G-Helix interconnects. The geometry effect on the mechanical compliance and electrical parasitics of G-Helix interconnects have been studied. Thinner and narrower arcuate beams with larger radius and taller post are found to have better mechanical compliance. However, it is also found that structures with excellent mechanical compliance may not have good electrical performance. Therefore, a trade off is needed. Using response surface methodology (RSM), an optimization has been done. Furthermore, reliability of the optimized G-helix interconnects in a silicon-on-organic substrate assembly has been assessed, which includes the package weight and thermo-mechanical analysis. The pitch size effect on the electrical and mechanical performance of G-Helix interconnects has also been studied.

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