Hygro-Mechanical Durability of Underfilled Flip-Chip-on-Board (FCOB) Interconnects

2002 ◽  
Vol 124 (3) ◽  
pp. 184-187 ◽  
Author(s):  
J. H. Okura ◽  
A. Dasgupta ◽  
J. F. J. M. Caers
Keyword(s):  
Flip Chip ◽  
Failure Modes ◽  
Moisture Absorption ◽  
Accelerated Aging ◽  
Accelerated Life Tests ◽  
Accelerated Life ◽  
Service Durability ◽  
Mechanical Durability ◽  
Life Tests ◽  
And Diffusion

The effect of constant temperature and humidity environments on the durability of interconnects in underfilled Flip-Chip-on-Board (FCOB) assemblies is investigated in this study. Polymeric underfills, used to enhance thermomechanical durability of the interconnects, are found to create new failure modes due to hygromechanical swelling. Based on experimental observations, the failure mechanism is hypothesized to be cracking of intermetallics, which have weakened due to thermal aging. Pseudo 3-D finite element analyses are conducted to quantify the moisture absorption and diffusion through the polymeric underfill, and the resulting hygromechanical viscoplastic stress history. The simulations are combined with accelerated aging tests to assess in-service durability in hot, humid environments. Model predictions are compared with results of accelerated life tests available in the literature.

Effect of Moisture on Durability of Flip-Chip-on-Board (FCOB) Interconnects

2000 ◽  
Author(s):  
J. H. Okura ◽  
A. Dasgupta ◽  
J. F. J. M. Caers
Keyword(s):  
Flip Chip ◽  
Failure Modes ◽  
Moisture Absorption ◽  
Accelerated Aging ◽  
Accelerated Life Tests ◽  
Accelerated Life ◽  
Model Predictions ◽  
Service Durability ◽  
Life Tests ◽  
And Diffusion

Abstract The effect of constant temperature and humidity environments on the durability of interconnects in underfilled Flip-Chip-on-Board (FCOB) assemblies is investigated in this study. Polymeric underfills, used to enhance thermomechanical durability of the interconnects, are found to create new failure modes due to hygromechanical swelling. Based on experimental observations, the failure mechanism is hypothesized to be cracking of intermetallics, which have weakened due to thermal aging. Pseudo 3-D finite element analyses are conducted to quantify the moisture absorption and diffusion through the polymeric underfill, and the resulting hygromechanical viscoplastic stress history. The simulations are combined with accelerated aging tests to assess in-service durability in hot, humid environments. Model predictions are compared with results of accelerated life tests available in the literature.

Accelerated Life Tests of Flip-Chips With Solder Bumps Down to 30 μm Diameter

2011 ◽  
Vol 2011 (1) ◽  
pp. 000985-000996 ◽  
Author(s):  
Rainer Dohle ◽  
Stefan Härter ◽  
Jörg Goßler ◽  
Jörg Franke
Keyword(s):  
Thermal Diffusion ◽  
Flip Chip ◽  
Solder Bump ◽  
Temperature Cycling ◽  
Sphere Diameter ◽  
Accelerated Life Tests ◽  
Flip Chips ◽  
Accelerated Life ◽  
Solder Bumps ◽  
Life Tests

In this study, accelerated life tests with ultra fine-pitch flip-chips with solder bumps down to 30 microns diameter have been performed. Tests commonly used like temperature cycling, high temperature storage, and humidity bias tests are not sufficient for such small packaging feature sizes any more. As solder bump sizes continue to decrease, along with the shrinkage of the solder pads and the scaling of line/space geometries, thermal diffusion has even more impact on reliability and lifetime of the solder connections, and current densities within single solder bumps increase. Therefore, electromigration of flip-chip interconnects is a significant reliability concern, especially when it comes to further miniaturization for high reliability applications. Since electromigration is a function of interconnect sizes and metallurgies, new interconnect developments need to be characterized for electromigration reliability. Flip-chips 10 mm × 10 mm × 0.8 mm in size with a die layout providing a pitch of 100 μm for solder bump sizes of 60 μm, 50 μm, 40 μm, or 30 μm diameter, respectively, have been used [1]. The SnAgCu alloy solder spheres were placed on a NiAu UBM realized in an electroless nickel process [2]. A daisy chain connection is integrated for each of the solder sphere sizes and each chip can separately be connected for online measurements during electromigration or reliability testing. A variety of current density and temperature combinations which is individually adapted to the respective solder sphere diameter has been used. Lifetime data were collected using online measurement through the daisy chains. Cross sectioning has been employed to analyze the influence of thermal diffusion as well as electromigration on the failure mechanism of the highly miniaturized solder joints. A prediction model for flip-chip interconnects with solder spheres down to 30 μm diameter will be outlined using Black’s equation.

Accelerated Aging vs. Shelf Aging

1930 ◽  
Vol 3 (1) ◽  
pp. 156-156
Author(s):  
Everett M. Follansbee
Keyword(s):  
Tensile Strength ◽  
Copper Wire ◽  
Accelerated Aging ◽  
Low Grade ◽  
Testing Laboratory ◽  
Accelerated Life Tests ◽  
Accelerated Life ◽  
Physical Testing ◽  
Life Tests ◽  
Diffused Light

Abstract SAMPLES of rubber-insulated wire were aged by exposing to the diffused light in the physical testing laboratory. The thickness of wall of rubber surrounding the tinned copper wire showed a variation from 0.030 to 0.065 inch (0.76 to 1.65 mm.). The thickness of wall of rubber surrounding the tinned copper wire showed a variation from 0.030 to 0.065 inch (0.76 to 1.65 mm.). The samples were tested for tensile strength and elongation during the aging interval and the results were then compared with accelerated life tests obtained on the same samples when new. Average results on 480 different compounds, ranging in quality from a low-grade compound to a compound containing 60 per cent by weight of crude rubber, show the following relationship between shelf aging and accelerated aging.

ANALYSES OF ACCELERATED LIFE TEST DATA UNDER TWO FAILURE MODES

2002 ◽  
Vol 09 (02) ◽  
pp. 111-125 ◽  
Author(s):  
C. M. KIM ◽  
D. S. BAI
Keyword(s):  
Failure Mode ◽  
Data Model ◽  
Failure Modes ◽  
Location Parameter ◽  
Estimation Procedure ◽  
Accelerated Life Test ◽  
Simulation Studies ◽  
Accelerated Life Tests ◽  
Accelerated Life ◽  
Life Tests

This paper proposes a method of estimating the lifetime distribution at use condition for constant stress accelerated life tests when an extrinsic failure mode as well as intrinsic one exists. A mixture of two distributions is introduced to describe these failure modes. It is assumed that the log lifetime of each failure mode follows a location-scale distribution and a linear relation exists between the location parameter and the stress. An estimation procedure using the expectation and maximization algorithm is proposed and specific formulas for Weibull distribution are obtained. Simulation studies are performed to investigate the properties of the estimates and the effects of stress level. Numerical comparisons with the masked data model are also performed.

Accelerated Life Tests with Competing Failure Modes

2019 ◽  
pp. 197-221
Author(s):  
Kanchan Jain ◽  
Preeti Wanti Srivastava
Keyword(s):  
Failure Modes ◽  
Accelerated Life Tests ◽  
Accelerated Life ◽  
Life Tests
Sign in / Sign up

Export Citation Format

Share Document