scholarly journals Solder reflow process induced residual warpage measurement and its influence on reliability of flip-chip electronic packages

2006 ◽  
Vol 46 (2-4) ◽  
pp. 512-522 ◽  
Author(s):  
Se Young Yang ◽  
Young-Doo Jeon ◽  
Soon-Bok Lee ◽  
Kyung-Wook Paik
Author(s):  
Toru Ikeda ◽  
Won-Keun Kim ◽  
Noriyuki Miyazaki

Recently, adhesively bonding techniques such as the anisotropic conductive film (ACF) or the non-conductive adhesive resin are often used for connections in the chip size packages instead of conventional solder joints due to their reasonable cost and the ease of miniaturization. Adhesively bonding techniques expected to be a key technology for the chip size packaging and the system in package. However, the level of reliability for adhesively bonding techniques is still less than that for solder joints. The quantitative evaluation techniques for the reliability of adhesively bonding techniques are desired. This paper focused on the reliability of adhesively bonding joints in a flip chip package during the solder reflow process for other solder jointed devices. This paper presents a methodology for quantitative evaluation of the delamination in a flip chip interconnected by an ACF under moisture/reflow sensitivity tests. The delamination toughnesses between components in a flip chip based on the stress intensity factors were measured by fracture tests in conjunction with the numerical analysis developed in our previous study. Moisture concentration after moisture absorption was expected by the diffusion analysis using the finite element method. Then, vapor pressure in a flip chip during the solder reflow process was estimated. Finally the delamination was predicted by comparing the stress intensity factor of an interface crack due to vapor pressure with the delamination toughness. The delaminations in an actual flip chip package during moisture/reflow sensitivity tests have successfully predicted by the present methodology.


2011 ◽  
Vol 2011 (DPC) ◽  
pp. 001898-001917
Author(s):  
Deok-Hoon Kim ◽  
Young-Sang Cho ◽  
Peter Elenius

The use of flip chip interconnects for image sensor packaging provides several unique challenges during packaging as well as benefits to the customer. The principal challenges during assembly include the requirements of: no contamination of the image sensor during reflow, fabrication of a sealing structure to prevent future environmental contamination of the image sensor, and fabrication of a solder joint structure for the seal ring that can pass pre-conditioning. To achieve these requirements, the use of a fluxless solder reflow process and transient liquid phase (TLP) bonding will be explained. Benefits to the customer for this type of flip chip image sensor packaging as compared to chip on board (COB) and thru silicon via (TSV) packages is a thinner camera module and versus TSV packages the ability to pass all required reliability tests without the use of an underfill. Reliability test results will be shown for thermal cycling, drop, and bending tests.


2020 ◽  
Vol 2020 (1) ◽  
pp. 000125-000130
Author(s):  
Leo Hu ◽  
Sze Pei Lim

Abstract With the leap into the 5G era, the demand for improvements in the performance of mobile phones is on the rise. This is also true for the quantity of radio frequency (RF) front-end integrated circuits (ICs), especially for RF switches and low noise amplifiers (LNA). It is well-known that improvements in performance depend on the combination of new design, package technology, and choice of materials. Ultra-low residue (ULR) flux is an innovative, truly no-clean, flip-chip bonding material. By using ULR flux, the typical water-wash cleaning process can be removed and, in some instances, package reliability can be improved as well. This simplified assembly process will help to reduce total packaging costs. This paper will discuss the application of ULR fluxes on land grid arrays (LGAs) and quad-flat no-leads/dual-flat no-leads (QFN/DFN) packages for RF front-end ICs, as well as the reflow process. The solder joint strength and reliability study will be shared as well.


2010 ◽  
Vol 2010 (1) ◽  
pp. 000156-000163
Author(s):  
Weijun Zhou ◽  
Quan Yuan ◽  
Chris Li ◽  
Stephen F. Hahn ◽  
Kurt A. Koppi ◽  
...  

A new class of thermoplastic optical polymers made by substantially fully hydrogenating block copolymers of styrene and butadiene, known as cyclic block copolymers (CBCs), were recently discovered to exhibit lead-free solder reflow resistance with peak reflow temperature up to 260°C. This kind of behavior is uncommon for traditional thermoplastic polymers. The block copolymer design and the resulting nanostructured morphology lead to strong elastic and soft solid material characteristics for CBC, which may explain why CBCs can maintain good dimensional stability at high temperatures (i.e., above its glass transition temperature, Tg) for a short period of time such as in a solder reflow process. This hypothesis was examined by computational fluid dynamics modeling on a molded CBC lens of LUXEON K2 LED package configuration. When the CBC lens is subjected to a simulated solder reflow process, the change in physical dimension due to thermal expansion and gravity effects is predicted to be negligible. However, the residual stress in the molded lens may play a profound role on its dimensional stability. There exists a critical stress value below which no observable deformation is predicted for the CBC lens. With excellent optical transparency and good long term optical stability, low moisture absorption, and good injection moldability, CBCs is a promising class of materials for LED packaging that contributes to improved LED manufacturing economics.


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