scholarly journals Solder Joint Reliability Risk Estimation by AI-Assisted Simulation Framework with Genetic Algorithm to Optimize the Initial Parameters for AI Models

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4835
Author(s):  
Cadmus Yuan ◽  
Xuejun Fan ◽  
Gouqi Zhang
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Solder Joint ◽  
Risk Estimation ◽  
Time Dependent ◽  
Simulation Framework ◽  
Solder Joint Reliability ◽  
Joint Reliability ◽  
Solder Joint Fatigue ◽  
The Impact

Solder joint fatigue is one of the critical failure modes in ball-grid array packaging. Because the reliability test is time-consuming and geometrical/material nonlinearities are required for the physics-driven model, the AI-assisted simulation framework is developed to establish the risk estimation capability against the design and process parameters. Due to the time-dependent and nonlinear characteristics of the solder joint fatigue failure, this research follows the AI-assisted simulation framework and builds the non-sequential artificial neural network (ANN) and sequential recurrent neural network (RNN) architectures. Both are investigated to understand their capability of abstracting the time-dependent solder joint fatigue knowledge from the dataset. Moreover, this research applies the genetic algorithm (GA) optimization to decrease the influence of the initial guessings, including the weightings and bias of the neural network architectures. In this research, two GA optimizers are developed, including the “back-to-original” and “progressing” ones. Moreover, we apply the principal component analysis (PCA) to the GA optimization results to obtain the PCA gene. The prediction error of all neural network models is within 0.15% under GA optimized PCA gene. There is no clear statistical evidence that RNN is better than ANN in the wafer level chip-scaled packaging (WLCSP) solder joint reliability risk estimation when the GA optimizer is applied to minimize the impact of the initial AI model. Hence, a stable optimization with a broad design domain can be realized by an ANN model with a faster training speed than RNN, even though solder fatigue is a time-dependent mechanical behavior.

scholarly journals Study on the Impact of Lead Sidewall Solder Coverage and Corner Lead Size on Joint Reliability

2021 ◽  
pp. 62-69
Author(s):  
Jefferson Talledo
Keyword(s):  
Solder Joint ◽  
Integrated Circuit ◽  
High Speed ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Element Analysis ◽  
Solder Joint Reliability ◽  
Joint Reliability ◽  
Solder Fatigue ◽  
The Impact

Solder joint reliability is very important to ensure that an integrated circuit (IC) semiconductor package is functional within its intended life span as the solder joint establishes electrical connection between the IC and the printed circuit board (PCB). Solder fatigue failure or crack under thermal cycling is one of the common problems with board-mounted packages. There are several factors or package characteristics that have impact on solder fatigue life like package size and material properties of the package components. This paper presents a thermo-mechanical modeling of a leadframe-based semiconductor package to study the impact of lead sidewall solder coverage and corner lead size on the solder joint reliability. Finite element analysis (FEA) technique was used to calculate the solder life considering 50% and 100% package lead sidewall solder coverage as well as smaller and larger critical corner leads of the package. The results of the analysis showed that higher lead sidewall solder coverage and larger lead could significantly increase solder life. Therefore, ensuring lead sidewall solder wettability to have higher solder coverage is beneficial. The study also reveals that packages with side wettable flanks are not only enabling high speed automated optical inspection required for the automotive industry, but they are also providing improved solder joint reliability.

ENEPIG Reliability - Enhancement by Simple Drop in Process Changes

2019 ◽  
Vol 2019 (DPC) ◽  
pp. 000531-000572
Author(s):  
Kuldip Johal ◽  
Rick Nichols
Keyword(s):  
Solder Joint ◽  
High Speed ◽  
Fluid Exchange ◽  
Solder Joint Reliability ◽  
Ball Grid Arrays ◽  
Joint Reliability ◽  
Controversial Topic ◽  
Controlled Deposition ◽  
Reliability Performance ◽  
The Impact

Soldering on ball grid arrays (BGAs) and dense circuit features is standard practice in the microelectronics industry. Key to the success of this operation is solder joint reliability (SJR). The evaluation of solder joint reliability can be satisfied by high speed shear testing (HSS). HSS testing in combination with representative test vehicles are tools that can be used to gain statistical data in order to evaluate the impact of controlled testing. During such a round of controlled testing in the context of a palladium phosphor ENEPIG process, it was observed that the palladium initiation speed and IMC may be related to HSS results. The focus of this paper is not targeting all the optimizations that can lead to high end reliability performance for solderability. This paper will strive to convey steps that are available to all fabricators to maximize High Speed Shear results (HSS). In this paper, it will be shown that soldermask related pinholes can be overcome by implementing a reduction assisted immersion gold bath. This section will also culminate in SJR improvements and stability. The prevention of pin holes is a complicated multifaceted problem. This paper will address the notion that, if pinholes are evident, an enhanced immersion gold bath can be used to overcome serious corrosion. Disturbances in the nickel deposit can be weaknesses that are open for unusual locally aggressive atom exchange between the gold and the nickel that will result is hyper-corrosion. A reduction assisted gold bath is able to mask such areas with controlled deposition. This paper will demonstrate the effectiveness of the optimized, purpose designed, gold bath in overcoming pinhole related corrosion whilst simultaneously scrutinizing the ability of the reduction assisted gold bath to maintain or enhance the reliability expectations that are benchmarked by traditional immersion gold alternatives. During studies it has also been observed that processing is also instrumental in assuring maximum soldering reliability. Whilst rinsing is an accepted procedure, the degree and method of rinsing is often a controversial topic. This is especially true of vertical processes where fluid exchange is replaced by soaking, or in other words agitation neutral, volume related dilution. Environmentally aware practices err on the side of minimal water consumption. This is a requirement that is influenced or selectively amplified by geographical locations. This technical paper will demonstrate that the palladium initiation is crucial if maximum SJR is to be achieved. This experience was gained in association with a significant OEM. Electrochemical and advanced optical techniques will be used to demonstrate that the SJR in terms of HSS can be correlated to palladium initiation and resultant IMC formations. In summary process adjustments can be employed to improve soldering performance and repetition. An optimized reduction assisted gold bath will come together with processing optimizations to provide a data driven overview to convince fabricators that enhancements to their everyday processes exist and can be implemented by drop in solutions. The data that is included should be as interesting to the automotive industry as it is to the emerging substrate like panel industry (SLP).

scholarly journals Probabilistic methodology for reliability assessment of electronic packages

2019 ◽  
Vol 286 ◽  
pp. 02002
Author(s):  
H. Hamdani ◽  
B. Radi ◽  
A. El Hami
Keyword(s):  
Solder Joint ◽  
Reliability Assessment ◽  
Temperature Cycling ◽  
Time Dependent ◽  
Electronic Packages ◽  
Finite Element Analyses ◽  
Material Parameters ◽  
Joint Reliability ◽  
Design Variables ◽  
Solder Joint Fatigue

In the mechatronic devices, the finite element analyses are the most used method to determine time-dependent solder joint fatigue response under accelerated temperature cycling conditions, the deterministic analyses are the most used methods. However, the design variables show variability and randomness which will affect the lifetime prediction quality. This paper focuses on solder joint reliability in tape-based chip-scale packages(CSP) with the consideration of uncertainties in material parameters.

Solder Joint Reliability Challenges in Sub 1.00 mm Ball Pitch for Flip Chip Ball Grid Array

2005 ◽  
Author(s):  
Keh Shin Beh ◽  
Wei Keat Loh ◽  
Jenn Seong Leong ◽  
Wooi Aun Tan
Keyword(s):  
Solder Joint ◽  
Flip Chip ◽  
Compressive Load ◽  
Heat Sinks ◽  
Thickness Effect ◽  
Solder Joint Reliability ◽  
Load Effect ◽  
Joint Reliability ◽  
Package Size ◽  
The Impact

FCBGA is an electronic package used to achieve a high Inputs/Outputs (I/Os). To continue to achieve a higher I/O count without increasing package size, ball pitch reduction is inevitable. However, ball pitch reduction using smaller ball size has posed substantial challenges to solder joint reliability (SJR). On top of that, rising power dissipation requirement in FCBGA package has created a need for high performance heat sinks. These heat sinks require significant compression loading to ensure good thermal conductance of thermal interface materials. The impact of these loads on SJR has typically not been considered in thermal cycle stressing. Hence, this paper focuses on different types of heat sinks and their compressive load effect on solder joint thermal fatigue performance. It also covers package size and board thickness effect when heat sink compressive load is taken into account during thermal stressing. Lastly, lead free and eutectic solders at sub 1.00mm ball pitch technology were also evaluated.

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