The Mechanics and Impact of Hygroscopic Swelling of Polymeric Materials in Electronic Packaging

2002 ◽  
Vol 124 (2) ◽  
pp. 122-126 ◽  
Author(s):  
E. H. Wong ◽  
R. Rajoo ◽  
S. W. Koh ◽  
T. B. Lim
Keyword(s):  
Thermal Stress ◽  
Electronic Packaging ◽  
Flip Chip ◽  
Polymeric Materials ◽  
Packaging Materials ◽  
Excellent Correlation ◽  
Reliable Technique ◽  
Hygroscopic Swelling ◽  
Solder Reflow ◽  
Swelling Characteristics

A reliable technique for characterizing the hygroscopic swelling of materials has been developed and used to characterize a number of packaging materials. Using these data, hygroscopic stress modeling were performed. The hygroscopic stress induced through moisture conditioning was found to be significant compared to the thermal stress during solder reflow. Hygroscopic stress in over-molded wire bond PBGA and molded Flip Chip PBGA was found to be 1.3 times to 1.5 times that of thermal stress. Hygroscopic swelling of the underfill in FCPBGA was found to be the main failure driver during autoclave test. Autoclave performance of FCPBGA package assembled with different underfills and chips were analyzed. Excellent correlation was found between autoclave performance and the hygroscopic swelling characteristics of the underfills.

The Research of Spraying SiC/Cu Electronic Packaging Composites

2011 ◽  
Vol 284-286 ◽  
pp. 620-623
Author(s):  
Ming Hu ◽  
Jing Gao ◽  
Yun Long Zhang
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Process Parameters ◽  
Electronic Packaging ◽  
High Speed ◽  
Volume Fraction ◽  
Flame Spraying ◽  
Packaging Materials ◽  
Excellent Performance ◽  
Chemical Plating

The SiC/Cu electronic packaging composites with excellent performance were successfully prepared by the chemical plating copper on the surface of SiC powders and high-speed flame spraying technology. The results showed that the homogeneous dense coated layers can be obtained on the surface of SiC powder by optimizing process parameters. The volume fraction of SiC powders in the composites could significantly increase and figure was beyond 55vol% after spraying Copper. The SiC and Cu were the main phases in the spraying SiC/Cu electronic packaging composite, at the same time Cu2O can be tested as the trace phase. The interface combination properties of SiC/Cu in the hot-pressed samples can obviously improve. The thermal expansion coefficient and thermal conductivity of SiC/Cu electronic packaging composite basic can satisfy the requirements for electronic packaging materials.

One Step Chip Attach Materials (OSCA) for Conventional Mass Reflow Processing

2014 ◽  
Vol 2014 (1) ◽  
pp. 000262-000267
Author(s):  
Daniel J. Duffy ◽  
Lin Xin ◽  
Jean Liu ◽  
Bruno Tolla
Keyword(s):  
Flip Chip ◽  
Polymeric Materials ◽  
Cure Kinetics ◽  
Filler Loading ◽  
Single Step ◽  
Seamless Integration ◽  
Device Reliability ◽  
One Step ◽  
Traditional Processing

One step chip attach (OSCA) materials are dispensable polymeric materials for flip chip assembly, which are designed to flux metallic interconnections and subsequently turn into an underfill upon curing. OSCA materials enable a drastic simplification of the assembly process by combining the reflow (fluxing/soldering), defluxing and capillary underfilling steps used in traditional processing into a single step. One key challenge for the design of OSCA materials is timing the cure kinetics with fluxing activity and solder reflow during processing. A second key challenge is to factor a process-friendly rheological design into the formulation. The OSCA material rheology must allow for high filler loading levels, seamless integration with standard dispensing equipment, flow control during and after dispense (avoid keep out zones), flow during die placement (elimination of voids), after placement (fillet formation) and during reflow. The final key requirements for a functional device are defect-free interconnections combined with optimal thermo-mechanical and water resistant properties of the final underfill to guarantee the long-term reliability of the assembly in various environmental conditions. This paper presents the properties of materials designed by Kester for use in mass reflow processing (OSCA-R). The rheological design principles behind a seamless integration into customer-friendly processes will be presented In addition results illustrating the timing of cure kinetics with fluxing and soldering events during processing will be discussed. Preliminary device reliability results will also be presented for several types of test vehicles including; Si-Si and Si-FR4.

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