Measurement of Mechanical Behavior of High Lead Lead-Tin Solder Joints Subjected to Thermal Cycling

1992 ◽  
Vol 114 (2) ◽  
pp. 135-144 ◽  
Author(s):  
Yi-Hsin Pao ◽  
Scott Badgley ◽  
Ratan Govila ◽  
Linda Baumgartner ◽  
Richard Allor ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Thermal Fatigue ◽  
Fracture Behavior ◽  
Solder Joints ◽  
Wheatstone Bridge ◽  
Shear Stresses ◽  
Stress Strain ◽  
Strain Behavior ◽  
Thermal Chamber ◽  
Creep Fatigue

Failures in electronic packages under thermal fatigue usually result from cracking in solder joints due to creep/fatigue crack growth. Understanding the stress/strain behavior of such solder joints is the first step in characterizing their fracture behavior. A specimen has been developed to determine the stress/strain hysteresis response of 90Pb/10Sn solder joints under cyclic thermal loadings. Simple and special techniques have been developed to fabricate solder joints with relatively high melting points, such as 90Pb/10Sn. Four high-temperature strain gages are mounted on the specimen to measure mechanical strains which provide the basis for determining the shear stress and strain in the solder. A special Wheatstone bridge has been designed to improve the specimen sensitivity, e.g., 20 με/MPa in the test. Shear stresses in the solder as low as 0.5 MPa can be resolved accurately. The specimen was subjected to thermal cycling between 40°C to 140°C, with 10°C/min ramp rate and 10 minute hold times, in a thermal chamber developed in-house. Excellent experimental results have been obtained for 90Pb/10Sn solder joints in that detailed characteristics of stress relaxation and strain creep as a function of temperature were captured. The specimen developed is not only suitable for use in studying the constitutive response of soft solder alloys and other joining materials, such as adhesives, but can serve as a thermal fatigue specimen to study the fracture behavior.

Predicting Thermal Fatigue Lifetimes for SMT Solder Joints

1992 ◽  
Vol 114 (4) ◽  
pp. 472-476 ◽  
Author(s):  
J. Sauber ◽  
J. Seyyedi
Keyword(s):  
Finite Element ◽  
Solder Joint ◽  
Thermal Cycling ◽  
Thermal Fatigue ◽  
Solder Joints ◽  
Finite Element Models ◽  
Creep Tests ◽  
Creep Equation ◽  
Joint Behavior ◽  
Creep Strains

A power-law type creep equation has been added to finite element models to calculate solder joint response to time, temperature, and stress level. The ability of the models to predict solder joint behavior was verified by running a series of creep tests. The models were then solved to determine the solder joint creep strains which occur during thermal cycling. These creep strains were used to predict the degradation of pull strength resulting from thermal cycling. More than 8,600 solder joints were thermally cycled and then individually pull tested to verify the accuracy of the method.

Reliability Evaluation of BGA Solder Joints by Using Thermal Fatigue Models

2005 ◽  
Author(s):  
Ouk Sub Lee ◽  
No Hoon Myoung ◽  
Dong Hyeok Kim
Keyword(s):  
Solder Joint ◽  
Thermal Cycling ◽  
Thermal Fatigue ◽  
Failure Probability ◽  
Solder Joints ◽  
State Function ◽  
Mechanical Loads ◽  
First Order ◽  
Reliability Method ◽  
Fatigue Model

The use of Ball Grid Array (BGA) interconnects utilizing the BGA solder joint has grown rapidly because of its small volume and diversity of its application. Therefore, the continuous quantification and refinement of BGA solder joint in terms of its reliability are required. The creep and cyclically applied mechanical loads generally cause metal fatigue on the BGA solder joint which inevitably leads to an electrical discontinuity. In the field application, the BGA solder joints are known to experience mechanical loads during temperature changes caused by power up/down events as the result of the Coefficient of Thermal Expansion (CTE) mismatch between the substrate and the Si die. In this paper, extremely small resistance changes in the lead free joints corresponding to the through-cracks generated by the thermal fatigue were measured and the failure was defined in terms of anomalous changes in the joint resistance. Furthermore, the reliability of BGA solder joints under thermal cycling was evaluated by using a criterion that may define and distinguish a failure in the solder joint. Any changes in circuit resistance according to the accumulated damage induced by the thermal cycling in the joint were recorded and evaluated by the First Order Reliability Method (FORM) procedure in order to quantify the reliability of solder joint. The first order Taylor series expansion of the limit state function incorporating with thermal fatigue models is used in order to estimate the failure probability of solder joints under heated condition. Various thermal fatigue models are utilized in this study. Models based on various plastic-strain rates such as Coffin-Manson fatigue model, total strain fatigue model and Solomon fatigue model are utilized in this study. The effects of random variables such as the CTE, the pitch of solder joint, the diameter of solder joint, and the CTE difference solder joints on the failure probability of the solder joint are systematically investigated by using a failure probability model with the FORM.

scholarly journals Creep-Fatigue Behaviours of Sn-Ag-Cu Solder Joints in Microelectronics Applications

2021 ◽  
Author(s):  
Joshua A. Depiver ◽  
Sabuj Mallik ◽  
Yiling Lu ◽  
Emeka H. Amalu
Keyword(s):  
Energy Density ◽  
Thermal Cycling ◽  
Strain Rate ◽  
Deformation Rate ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Solder Joints ◽  
Creep Fatigue ◽  
Accelerated Thermal Cycling ◽  
Isothermal Ageing

Electronic manufacturing is one of the dynamic industries in the world in terms of leading technological advancements. Electronic assembly’s heart lies the ‘soldering technology’ and the ‘solder joints’ between electronic components and substrate. During the operation of electronic products, solder joints experience harsh environmental conditions in terms of cyclic change of temperature and vibration and exposure to moisture and chemicals. Due to the cyclic application of loads and higher operational temperature, solder joints fail primarily through creep and fatigue failures. This paper presents the creep-fatigue behaviours of solder joints in a ball grid array (BGA) soldered on a printed circuit board (PCB). Using finite element (FE) simulation, the solder joints were subjected to thermal cycling and isothermal ageing. Accelerated thermal cycling (ATC) was carried out using a temperate range from 40°C to 150°C, and isothermal ageing was done at −40, 25, 75 and 150°C temperatures for 45 days (64,800 mins). The solders studied are lead-based eutectic Sn63Pb37 and lead-free SAC305, SAC387, SAC396 and SAC405. The results were analysed using the failure criterion of equivalent stress, strain rate, deformation rate, and the solders’ strain energy density. The SAC405 and SAC396 have the least stress magnitude, strain rate, deformation rate, and strain energy density damage than the lead-based eutectic Sn63Pb37 solder; they have the highest fatigue lives based on the damage mechanisms. This research provides a technique for determining the preventive maintenance time of BGA components in mission-critical systems. Furthermore, it proposes developing a new life prediction model based on a combination of the damage parameters for improved prediction.

Stress-Strain Behavior of a Fe-Ni-Cr Alloy During In-and Out-of-Phase Synchronized Thermal Cycling and Mechanical Cycling Tests

1999 ◽  
Vol 27 (1) ◽  
pp. 69
Author(s):  
DR Petersen ◽  
RE Link ◽  
Q He ◽  
J Bressers ◽  
E Fenske ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Stress Strain ◽  
Strain Behavior ◽  
Mechanical Cycling
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