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Article
Publication date: 1 August 2000

Shi‐Wei Ricky Lee and John H. Lau

A computational parametric study on the solder joint reliability of a plastic ball grid array (PBGA) with solder bumped flip chip (FC) is presented. The basic…

Abstract

A computational parametric study on the solder joint reliability of a plastic ball grid array (PBGA) with solder bumped flip chip (FC) is presented. The basic configuration of the PBGA is 27mm package‐size and 1.27mm ball‐pitch. There were three kinds of ball population: four‐row perimeter grid array with/without thermal balls, and full grid array. A total number of 24 cases, involving various chip sizes, chip thicknesses and substrate thicknesses, were studied. The diagonal cross‐section of the PBGA‐printed circuit board (PCB) assembly was modeled by plane‐strain elements and was subjected to uniform thermal loading. Through mismatch of coefficient of thermal expansion (CTE), and lack of structural compliance, the solder joints were stressed to produce inelastic deformation. The accumulated effective plastic strain was evaluated as an index for the reliability of solder joints. The present study revealed the effects of aforementioned design parameters on the solder joint reliability of FC‐PBGA assemblies. Some peculiar phenomena were identified.

Details

Soldering & Surface Mount Technology, vol. 12 no. 2
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 1 June 1997

S.‐W.R. Lee and J.H. Lau

Computational stress analysis was performed in this study to investigate thesolder joint reliability of plastic ball grid array (PBGA) packages with variousconfigurations…

Abstract

Computational stress analysis was performed in this study to investigate the solder joint reliability of plastic ball grid array (PBGA) packages with various configurations. The packages under investigation were 27 mm body‐size, 1.27 mm ball‐pitch, perimeter PBGAs with and without thermal balls at the centre. The diagonal cross‐section of the PBGA‐printed circuit board (PCB) assembly was modelled by plane‐strain elements. The model was subjected to a uniform thermal loading and the solder joints were stressed due to the mismatch of coefficient of thermal expansion (CTE). A total number of 24 cases, involving different solder ball populations, chip sizes, and substrate thicknesses, were studied. The accumulated effective plastic strain was evaluated as an index for the reliability of solder joints. The results of this study revealed the effects of the aforementioned parameters on the solder joint reliability of perimeter PBGA assemblies. The findings are very useful for the design of plastic ball grid array packages.

Details

Circuit World, vol. 23 no. 2
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 26 July 2013

Chong Leong Gan, Francis Classe and Uda Hashim

The purpose of this paper is to provide a systematic method to perform long‐term reliability assessment of gold (Au) and copper (Cu) ball bonds in fineline ball grid array

Abstract

Purpose

The purpose of this paper is to provide a systematic method to perform long‐term reliability assessment of gold (Au) and copper (Cu) ball bonds in fineline ball grid array package. Also with the aim to study the apparent activation energies (Eaa) and its associated wearout mechanisms of both Au and Cu wire in semiconductor device packaging. This paper discusses the influence of wire type on the long‐term reliability and mechanical performance after several component reliability stress tests.

Design/methodology/approach

A fineline ball grid array (FBGA) package with Cu and Au wire bonds was assembled with green molding compound and substrate. Samples are subjected for long‐term high temperature storage bake test at elevated temperatures of 150°C, 175°C and 200°C. Long‐term reliability plots (lognormal plots) are established and Eaa of both ball bonds are determined from Arrhenius plots. Detailed failure analysis has been conducted on failed sample and HTSL failure mechanisms have been proposed.

Findings

Reliability results show Au ball bond in FBGA package is observed with higher hour‐to‐failure compared to Cu ball bonds. The Eaa value of high temperature storage life (HTSL) reliability for Au ball bond is lower than Cu ball bond. Typical HTSL failure mechanism of Au ball bond is induced by micro‐voiding and AuAl intermetallic compound (IMC) micro‐cracks while CuAl IMC micro‐cracking (induced by Cl corrosion attack and micro‐cracking) caused wearout opens in Cu ball bond. These test results affirm the test‐to‐failure data collected is a useful method for lifetime prediction and Eaa calculation.

Practical implications

The paper reveals higher reliability performance of Cu ball bond in FBGA flash memory package which can be deployed in flash memory FBGA packaging with optimised package bill of materials.

Originality/value

The test‐to‐failure methodology is a useful technique for wearout reliability prediction and Eaa calculation.

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Article
Publication date: 1 April 1997

G. Hill

Plastic ball grid arrays (PBGAs) have begun to gain popularity in the electronic packaging marketbecause of their advantages over peripheral leaded devices. In addition to…

Abstract

Plastic ball grid arrays (PBGAs) have begun to gain popularity in the electronic packaging market because of their advantages over peripheral leaded devices. In addition to good electrical performance, the PBGAs offer advantages to the assembler. The development of a successful assembly process for PBGAs requires an understanding of the PBGA itself and the assembly process. The key attributes required for high yield manufacturing of PBGAs are discussed. The emphasis is placed on the PBGA assembly parameters including proper PBGA handling, printing , stencil design, placement, reflow and inspection. This paper is intended to increase the understanding of the plastic ball grid array manufacturing process.

Details

Microelectronics International, vol. 14 no. 1
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 1 December 1996

W. Engelmaier

Highly accelerated tests, while capable of producing failures in short test durations, cancause significant damage and failure as a result of damage mechanisms and/or…

Abstract

Highly accelerated tests, while capable of producing failures in short test durations, can cause significant damage and failure as a result of damage mechanisms and/or material behaviour not present in the actual use of electronic product. This is particularly true for surface mount solder attachments. The results of low‐acceleration reliability tests for the solder attachments of ball grid arrays (BGAs) and column grid arrays (CGAs) are reported in this paper. The tests were designed to mimic the thermal conditions of the use environment of the product, including internal power dissipation within the grid array components, as closely as practically possible. The test acceleration comes from two measures taken: (1) controlled reduced dwell times at the cyclic temperature extremes, thus allowing a higher cyclic frequency, and (2) a controlled increased CTE‐mismatch between the components and the test circuit board by an increase in the coefficient of thermal expansion (CTE) of the test circuit boards relative to the product cirucit boards. Control test vehicles with product‐like circuit board construction were also utilised. The results from the different test vehicle configurations are correlated and utilised to estimate the reliability of the product in the field.

Details

Soldering & Surface Mount Technology, vol. 8 no. 3
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 1 February 1994

J. Lau, J. Miremadi, J. Gleason, R. Haven, S. Ottoboni and S. Mimura

A no‐clean mass reflow process for 396‐pin, 324‐pin and 225‐pin over moulded plastic pad array carriers (OMPACs) or plastic ball grid array (BGA) is presented. Emphasis is…

Abstract

A no‐clean mass reflow process for 396‐pin, 324‐pin and 225‐pin over moulded plastic pad array carriers (OMPACs) or plastic ball grid array (BGA) is presented. Emphasis is placed on the OMPAC assembly parameters such as the design, material and process of the packages and printed circuit board (PCB), solder paste, stencil design, printing technology, pick and place, mass re‐flow and inspection. Furthermore, cross‐sections and the ‘popcorn’ effect of the OMPAC assembly are provided and discussed.

Details

Circuit World, vol. 20 no. 3
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 1 March 1997

S.‐W. Lee and J.H. Lau

This paper presents a non‐linear numerical study to investigate the effectof chip dimension and substrate thickness on the solder joint reliability of plastic ball grid

Abstract

This paper presents a non‐linear numerical study to investigate the effect of chip dimension and substrate thickness on the solder joint reliability of plastic ball grid array (PBGA) packages. The package under investigation was a 225‐pin full‐grid PBGA assembly. The diagonal cross‐section of the PBGA together with the printed circuit board (PCB) was modelled by plane‐strain elements. A uniform thermal loading was applied and the solder joints were stressed due to the mismatch of coefficient of thermal expansion (CTE) and constructions of the PCB assembly. The effective stress and accumulated plastic strain of solder balls against various chip dimensions and substrate thicknesses were evaluated as an index for the reliability of solder joints. The results of this study are helpful for electronics packaging engineers to optimise the geometry of plastic ball grid array packages.

Details

Circuit World, vol. 23 no. 1
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 1 April 1998

S.‐W. Ricky Lee and John H. Lau

A computational model was established in this study to simulate cavity‐down plastic ball grid array (PBGA) assemblies. Stress analysis was performed to investigate the…

Abstract

A computational model was established in this study to simulate cavity‐down plastic ball grid array (PBGA) assemblies. Stress analysis was performed to investigate the solder joint reliability of a PBGA‐PCB (printed circuit board) assembly. The packages under investigation had two different body sizes and two kinds of ball population. The diagonal cross‐section of the assembly was modeled by plane‐strain elements and was subjected to a uniform thermal loading. The solder joints were stressed due to the mismatch of the assembly’s coefficient of thermal expansion (CTE). The accumulated effective plastic strain was evaluated as an index for the reliability of solder joints. Effects on solder joint reliability such as package size and ball population were identified. Furthermore, it was found that, unlike conventional PBGA assemblies, the outermost solder ball has the highest plastic strain for all cases in the present study. This peculiar phenomenon was further discussed with the consideration of package deformation.

Details

Soldering & Surface Mount Technology, vol. 10 no. 1
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 1 August 1997

L. Anderson and A.A. Primavera

As plastic ball grid array(PBGA) components proliferate, card assembly questions arise about the robustness of themodule to card attachment process. A designed experiment…

Abstract

As plastic ball grid array (PBGA) components proliferate, card assembly questions arise about the robustness of the module to card attachment process. A designed experiment was performed to measure the sensitivity of card assembly yields to normal assembly process variation. Experimental variables include card thickness, ball pad size on the card ball grid array (BGA) site, module moisture exposure and ball planarity of a 225 I/O PBGA. Another set of PBGA test cards, assembled under optimum process conditions, was subjected to accelerated thermal cycle (ATO) testing. ATC testing also included a rework cell. Overall, the PBGA module attachment process demonstrated robustness. The initial attach and reworked modules proved to be reliable. This paper focuses on the details of the test conditions and the results.

Details

Microelectronics International, vol. 14 no. 2
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 1 April 1996

R. Munamarty, P. McCluskey, M. Pecht and L. Yip

Two types of Plastic ball Grid array packages, a225‐lead full matrix array and a 256‐lead perimeter array, were subjected to 168 hours of moisturepreconditioning at 85°C…

Abstract

Two types of Plastic ball Grid array packages, a 225‐lead full matrix array and a 256‐lead perimeter array, were subjected to 168 hours of moisture preconditioning at 85°C and 30% relative humidity followed by simulated infra‐red reflow at temperature ramp rates of 1°C/s and 0.67°C/s. The packages were subsequently examined for delamination and cracking using scanning acoustic microscopy and environmental scanning electron microscopy. At the higher ramp rate, delamination and cracking were observed in both package types, originating in the die attach and propagating along the weakest interfaces. At the lower ramp rate, a small amount of delamination was observed. This suggests that there is a critical ramp rate below which popcorn cracking does not occur.

Details

Soldering & Surface Mount Technology, vol. 8 no. 1
Type: Research Article
ISSN: 0954-0911

Keywords

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