Effects of Material Properties and Thickness of Die Attach on Warpage and Stresses of TSOP

2011 ◽  
Vol 264-265 ◽  
pp. 542-547
Author(s):  
Chia Lung Chang ◽  
P.Y. Chen ◽  
M.H. Huang
Keyword(s):  
Nonlinear Model ◽  
Material Properties ◽  
Residual Deformation ◽  
Primary Factor ◽  
Chemical Shrinkage ◽  
Process Step ◽  
Electronic Package ◽  
Molding Compound ◽  
Die Attach ◽  
Plastic Package

The assembly of plastic electronic package requires a sequence of process steps. Every process step induces thermal residual deformation and stresses on the assembled components, which cause mechanical effects on the subsequent process step. Processing model with considering the effect of chemical shrinkage on molding compound is built to simulate the package warpage and stresses in assembly. The processing model, a nonlinear model with element birth and death used to activate and deactivate the processing materials, can more realistically simulate a series of assembly processes in a plastic package. The stresses in package components are primary factor for the damage of package. The induced package stresses can cause the delamination between die/die attach interface or die attach/die pad interface. In this study, effects of material properties as well thickness of die attach on warpage and stresses of TSOP (Thin Small Outline Package) during assembly are discussed.

Package Warpage and Stress Evaluation for a Plastic Electronic Package

2008 ◽  
Vol 33-37 ◽  
pp. 1327-1332 ◽  
Author(s):  
Chia Lung Chang ◽  
Chia Huei Chiou
Keyword(s):  
Nonlinear Model ◽  
Residual Deformation ◽  
Significant Error ◽  
Intermediate Step ◽  
Chemical Shrinkage ◽  
Process Step ◽  
Stress Evaluation ◽  
Electronic Package ◽  
Molding Compound ◽  
Plastic Package

The assembly of plastic electronic package requires a sequence of process steps. Every process step induces thermal residual deformation and stresses on the assembled components, which cause mechanical effects on the subsequent process step. In this study, both processing and non-processing models with and without considering the effect of chemical shrinkage on molding compound are built to simulate the package warpage and stresses in assembly. The processing model, a nonlinear model with element birth and death used to activate and deactivate the processing materials, can more realistically simulate a series of assembly processes in a plastic package. Due to negligence of the intermediate step, the package warpage and stresses predicted by non-processing model are in significant error.

Effect of Material Properties and Thickness of Die Attach on Delamination of Die Attach/Die Paddle Interface in Electronic Package

2010 ◽  
Author(s):  
Chia-Lung Chang ◽  
Po-Hsien Li
Keyword(s):  
Material Properties ◽  
Coefficient Of Thermal Expansion ◽  
Damage Parameter ◽  
Stress And Strain ◽  
Thermal Expansion Mismatch ◽  
The Finite Element Method ◽  
Electronic Package ◽  
Die Attach ◽  
Encapsulation Process ◽  
Die Bonding

The electronic package is a multi-layered structure that is consisted of several materials. Under the temperature loadings, the interfacial stresses between layered components are generated due to the CTE (coefficient of thermal expansion) mismatch between different materials. In die bonding process, the void or defect might exist at the die attach/die paddle interface. The void cause further delamination on the interface during the encapsulation process. In this study, the finite element method is used to construct the model of electronic package with a void on the die attach/die paddle interface. The energy release rate based on J integration, which is calculated by the stress and strain around the tip of crack, is used as a damage parameter to predict the tendency of further delamination during encapsulation. Effect of material properties (Young’s modulus and CTE) and die attach thickness on delamination of die attach/die paddle interface in package during encapsulation is studied.

Investigation of Transfer Mold Process Effects on Semiconductor Package Warpage

2009 ◽  
Author(s):  
Jason M. Brand ◽  
Myung J. Yim ◽  
Ravi Kumar
Keyword(s):  
Solder Joint ◽  
Material Property ◽  
Material Properties ◽  
Coefficient Of Thermal Expansion ◽  
Filler Concentration ◽  
Packaging System ◽  
Property Variation ◽  
Molding Compound ◽  
Fea Model ◽  
Die Attach

In recent years, Package on Package (PoP) is increasingly used for high density package solutions. Generally the top package is a stacked memory packaging system connected to a bottom logic packaging system via solder joint: this is representative of PoP configurations. To guarantee the assembly yield and reliability of the solder joint between the top package and bottom package, mechanical compliance between these two packages is crucial during package stacking. Henceforth package warpage needs to be understood and controlled to meet the assembly yield targets. The complexity of the package configuration increases by thinner package thickness, higher number of stacking dies and large package size. Controlling the warpage within the target requirement is very challenging, especially when the material behaviors of substrate, die, molding compound and die attach film are different and also changing as a function of temperature. Certainly, the material properties of key components in top PoP package plays a crucial role in warpage performance. Among various material properties, the chemical cure shrinkage, coefficient of thermal expansion and storage modulus for the molding compounds are determining factors on the temperature dependant warpage control of top PoP package. Warpage variation still exists within parts processed at the same time mainly due to slight material property variation. In this paper, the cause of the warpage variation is investigated. The main cause was found to be filler migration effect in narrow gaps with in the stacked die package during the mold process, which resulted in different filler concentration and distribution, and finally different local molding compound material property among the package unit location in the substrate strip. The findings indicate that mold pressure is not a major modulator of warpage, while filler distribution can dramatically alter the warpage behavior. FEA model results and warpage data are presented to validate the filler migration phenomena and warpage behavior impact. The findings and results provide some clues and design/process guideline for warpage control in Top PoP package, which influence the PoP assembly yield and reliability.

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).

MEMS Die Warpage During Curing of Die Attach Material

2015 ◽  
Author(s):  
Hohyung Lee ◽  
Ruiyang Liu ◽  
Seungbae Park ◽  
Xiaojie Xue
Keyword(s):  
Material Properties ◽  
Residual Strain ◽  
Critical Role ◽  
Measurement Data ◽  
Curing Process ◽  
Assembly Process ◽  
Structural Elements ◽  
Mems Sensor ◽  
Fea Model ◽  
Die Attach

Microelectromechanical system (MEMS) packages are vulnerable to stresses due to its functional structure. During the assembly process of the package, stresses stemming out of CTE mismatches of the structural elements and curing of the die attach material can cause warpage of the MEMS die [1]. Even though die attach material takes relatively small volumetric portion of the package, it plays a critical role in warpage of the die due to its location and sensitivity of a MEMS sensor. Most of virgin die attach adhesives are in a state of viscous liquid and, as it is cured the material properties such as modulus and CTE change. Accordingly, residual strain is cumulated on MEMS die after curing process and signal trim process is required. Therefore, the material properties changes depending on the curing profile is valuable information for assembly process of the MEMS package. To monitor the material properties changes and shrinkage during curing process, strain and modulus of a die attach material are measured in each curing step. Also, to investigate the material property change depending on the curing profile, two different curing profiles are used. Experimental data show that die attach materials are gradually cured after each thermal cycling, which cause the increment of the modulus and glass transition temperature (Tg) with shrinkage at elevated temperature. Using the measurement data, FEA model is built to predict the warpage of the MEMS die. In the FEA model, residual strain on MEMS die is calculated by inputting material properties of die attach in each curing step. Also, die warpage of the package during the curing process is monitored using an optical profiler for the validation of the simulation results.

scholarly journals Development of Combined Manufacturing Technologies for High-Strength Structural Components

2010 ◽  
Vol 137 ◽  
pp. 219-246 ◽  
Author(s):  
Berend Denkena ◽  
Bernd Breidenstein ◽  
Luis de Leon ◽  
Jan Dege
Keyword(s):  
Material Properties ◽  
High Strength ◽  
Tool Geometry ◽  
Structural Components ◽  
Deep Rolling ◽  
Process Step ◽  
Single Process ◽  
Local Modification ◽  
Manufacturing Technologies ◽  
Finishing Processes

Novel manufacturing technologies for high-strength structural components of aluminium allow a local modification of material properties to respond to operational demands. Machining and finishing processes for changing material properties like deep rolling or rubbing are to be combined to a single process step. The intention is the controlled adjustment of the component’s properties by the modification of its subsurface. For that purpose the essential understanding of the interaction mechanisms of the basic processes turning, deep rolling and rubbing is necessary. Influences of the tool geometry as well as of the process parameters on the material properties are investigated. The results will be extended by parameter studies within numerical simulations. Thereafter, combinations of the basic processes in process sequences are analyzed to their ability to modify the subsurface properties. In consideration of these results, a prototypic combined turn-rolling tool is developed

scholarly journals Visco-Elastic Analysis for Warpage of Electronic Package Considering Change in Material Properties of Mold Resin Caused by Reflow Heating

2011 ◽  
Vol 14 (2) ◽  
pp. 128-135 ◽  
Author(s):  
Yasuhiro Naka ◽  
Michihiro Kawashita ◽  
Koji Sasaki ◽  
Kazunari Suzuki ◽  
Yasumi Tsutsumi ◽  
...  
Keyword(s):  
Material Properties ◽  
Elastic Analysis ◽  
Electronic Package

Red Phosphorous Induced Shorts in Plastic Packages

2004 ◽  
Author(s):  
Rafael Huerta ◽  
Nevil Wu
Keyword(s):  
Three Dimensions ◽  
Red Phosphorus ◽  
Molding Compound ◽  
X Ray ◽  
Analysis Techniques ◽  
Plastic Packages ◽  
Plastic Package ◽  
Wet Chemical ◽  
Inorganic Phosphorous ◽  
Phosphorous Compounds

Abstract Red phosphorous is one of the inorganic phosphorous compounds used as a flame retardant in microelectronic applications. One of the concerns is a red phosphorus induced pin-to-pin short in the molding compound. This paper discusses the red phosphorous-induced shorts in a 100 Lead TQFP (14x20x1.4mm) plastic package. The devices first failed on boards in the field. After de-soldering them from the boards, the devices were tested and found to have resistive pin-to-pin shorts. Common failure analysis techniques, including parallel lapping, cross sectioning, and X-ray, failed to reveal the resistive shorts and the shorting mechanism. Removing the molding compound by means of a wet chemical etching method using sulfuric acid on a hot plate worked very well and enabled to expose particles in three dimensions. It was concluded that the resistive shorts were not necessarily due to a single large phosphorous particle, but due to small and fragmented pieces of phosphorous.

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