Viscoelastic properties of solder pastes and isotropic conductive adhesives used for flip-chip assembly

2008 ◽  
Author(s):  
R. Durairaj ◽  
S. Mallik ◽  
A. Seman ◽  
A. Marks ◽  
N.N. Ekere
Keyword(s):  
Viscoelastic Properties ◽  
Flip Chip ◽  
Conductive Adhesives ◽  
Isotropic Conductive Adhesives ◽  
Solder Pastes ◽  
Flip Chip Assembly

Evaluation of a Conductive Adhesive Based Approach to Lead Free Flip Chip Assembly

2002 ◽  
Author(s):  
Muthiah Venkateswaran ◽  
Peter Borgesen ◽  
K. Srihari
Keyword(s):  
High Speed ◽  
Flip Chip ◽  
Printed Circuit Board ◽  
Critical Evaluation ◽  
Conductive Adhesive ◽  
Circuit Board ◽  
Lead Free ◽  
Conductive Adhesives ◽  
Flip Chip Assembly ◽  
Placement Machine

Electrically conductive adhesives are emerging as a lead free, flux less, low temperature alternative to soldering in a variety of electronics and optoelectronics applications. Some of the potential benefits are obvious, but so far the adhesives have some limitations as well. The present work offers a critical evaluation of one approach to flip chip assembly, which lends itself particularly well to use with a high speed placement machine. Wafers were bumped by stencil printing of a thermoset conductive adhesive, which was then fully cured. In assembly, the conductive adhesive paste was stencil printed onto the pads of a printed circuit board and cured after die placement. The printing process was optimized to ensure robust assembly and the resulting reliability assessed.

Reliability Investigation for Encapsulated Isotropic Conductive Adhesives Flip Chip Interconnection

2005 ◽  
Vol 128 (3) ◽  
pp. 177-183 ◽  
Author(s):  
Liu Caroline Chen ◽  
Zonghe Lai ◽  
Zhaonian Cheng ◽  
Johan Liu
Keyword(s):  
Flip Chip ◽  
Fem Simulation ◽  
Lifetime Measurement ◽  
Elastic Model ◽  
Conductive Adhesives ◽  
Electronic Manufacturing ◽  
Thermal Fatigue Life ◽  
Isotropic Conductive Adhesives ◽  
Product Lifetime ◽  
Chip Size

Isotropic conductive adhesives (ICA) are gaining more and more application interests in electronic manufacturing, however, their failure mechanism is not been fully understood. In this paper we present reliability investigations on an encapsulated ICA flip chip interconnection. Experimental work included product lifetime measurement, cross section observation, and whole module warpage scanning. Results revealed that the chip-size effect on the ICA lifetime was obvious. A theoretical analysis was conducted with Finite Element Method (FEM) simulation. Viscoelastic models for adhesives and underfill materials were employed, and the comparison with an elastic model was made. Calculated equivalent stresses Seqv and shear stress σxy fitted well with the experimental lifetime measurement, thus a lifetime relationship similar to the Coffin-Manson formula was established to predict the thermal fatigue life of an encapsulated ICA flip chip. Furthermore, the influences of underfill properties on the ICA reliability were discussed.

Sub process challenges in ultra fine pitch stencil printing of type‐6 and type‐7 Pb‐free solder pastes for flip chip assembly applications

2005 ◽  
Vol 17 (1) ◽  
pp. 24-32 ◽  
Author(s):  
G.J. Jackson ◽  
M.W. Hendriksen ◽  
R.W. Kay ◽  
M. Desmulliez ◽  
R.K. Durairaj ◽  
...  
Keyword(s):  
Flip Chip ◽  
Stencil Printing ◽  
Fine Pitch ◽  
Solder Pastes ◽  
Flip Chip Assembly ◽  
Free Solder
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