Impact of PBGA-ball-coplanarity on formation of solder joints

Miremadi, Jian

doi:10.1109/ectc.1995.517819

Cited by 11 publications

(7 citation statements)

References 10 publications

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“…Unless the fpBGA is twisting due to an unusual 3D effect, the warpage is generally the vertical deflection from the horizontal seating plane. Reducing this warpage is important for improving the singulation process, reducing package bending and shearing stresses [3], minimizing coplanarity problems [4], and increasing solder joint reliability. For solder joint reliability in particular, the out-of-plane alignment of solder balls (coplanarity problem) due to thermo-mechanical warpage can result in unsoldered or mechanically weakened joints [5], shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Warpage prediction of fine pitch BGA by finite element analysis and shadow moiré technique

Ke-min

Chen

et al. 2009

2009 International Conference on Electronic Packaging Technology &Amp; High Density Packaging

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Warpage is one of the major concerns in manufacturing BGA, CSP, POP or QFN based array packages because a reasonably flat package is critical to successful singulation and board level assembly processes. Warpage of a package is a result of curing shrinkage of encapsulated mold compounds (EMC) and CTE mismatch between various packaging materials. In a completed package, all components are bound together by the crosslinked polymers, i.e. EMC and dieattaching adhesive (D/A). No component can expand or shrink freely. In a typical array package, warpage is in the form of either a 'crying' face (corners facing downward) or a 'smiling' face (corners facing upward), depending on the correlations of the packaging materials' mechanical, physical and chemical properties.Fine pitch ball grid array (fpBGA) is a chip scale package offering a competitive solution for mobile applications. Package thickness ranges from 1.4mm down to 0.6mm with ball pitches as small as 0.4mm. Since the package is very thin, warpage control is a big challenge. In this study, an accurate finite element model, incorporated appropriate material properties was developed to predict the warpage of fpBGA under reflow condition. The experimental measurements of the warpage behavior of the fpBGA under solder-reflow condition were conducted using an Akrometrix TherMoire PS200. The experimental results were compared with the results of FE analysis, which provides feedbacks for modeling optimization. Effects of material properties and geometric parameters on thermal warpage were then studied using the optimized models.

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Section: Introductionmentioning

confidence: 99%

Warpage prediction of fine pitch BGA by finite element analysis and shadow moiré technique

Ke-min

Chen

et al. 2009

2009 International Conference on Electronic Packaging Technology &Amp; High Density Packaging

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“…The reliability of a BGA chip is strongly dependent on these solder balls that must be mounted to meet specifications for ball location, ball size and ball coplanarity [2] in the ball placement process. However, the ball placement process is complex, and is influenced by many process factors such as flux paste, ball acquisition, ball-to-pad alignment and ball deposition.…”

Section: Introductionmentioning

confidence: 99%

A fast full-field 3D measurement system for BGA coplanarity inspection

Yen

Tsai

2003

The International Journal of Advanced Manufacturing Technology

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Ball-Grid-Array (BGA) has become one of the most popular packaging techniques in the electronic industry. Coplanarity inspection of BGA solder balls is critical in BGA manufacturing for process and quality control. Currently, the 3D measurement systems for BGA coplanarity inspection are mainly based on laser scanning techniques. However, they suffer from low inspection speed due to the physical line-scanning process. In this paper, a fast and cost-effective 3D measurement system for coplanarity inspection of BGA solder balls is proposed. The proposed system uses an LCD-based phase measuring technique to perform full-field 3D measurement of BGA solder balls with high accuracy. Experiments have shown that the coplanarity measurement of BGA solder balls is very efficient and effective with the proposed system. The measurement repeatability is in the micrometer range.The processing time of the proposed 3D measurement system for an image of 640×480 pixels is less than 2 seconds on a typical personal computer.

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“…From the work of Miremadi [7], the Universal Consortium [6], and this study, it can be inferred that the contribution of ball size and warpage to coplanarity may not be equal and linear. Assembly processes might be able to tolerate higher non-planarities induced from the ball size variation than those from warpage.…”

mentioning

confidence: 92%

“…Miremadi [7] showed for 33mm body, 225 I/O, PBGA packages in OMPAC configuration (die-up), fiom a supplier, that the assembly processes could tolerate coplanarities higher than 8 mils. Miremadi induced the non-planarity by modifling the outermost balls.…”

mentioning

confidence: 99%

Effect of substrate warpage on the second level assembly of advanced plastic ball grid array (PBGA) packages

Rao

Prakash²

Twenty First IEEE/CPMT International Electronics Manufacturing Technology Symposium Proceedings 1997 IEMT Symposium

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Shadow Moire technique was used to study the out-of-plane displacements that represent warpage of advanced Plastic Ball Grid Array (PBGA) packages. Two types of PBGA packages, die-up and cavity-down configurations, were studied. The latter type is usually known as Enhanced Plastic Ball Grid Array (EPBGA) package due to the advantage it offers for thermal dissipation.Shadow Moire studies indicated that cavitydown package substrates warp in a concave configuration. Die-up package substrates warp in a convex configuration. Increase in temperatures up to 24OoC had an insignificant effect on the warpage of cavity-down substrates, whereas the die-up package substrate warpage improved with increasing temperature.However, the die-up substrates reverted to their original warpage upon cooling.The sum of the warpage and the ball diameter variation account for almost all the non-planarity. The packages with worse coplanarities showed invariably worse warpages. Substrate warpage of 4 mils or less is required for the successkl assembly of PBGA packages. Since cavity-down packages do not show any improvement with increasing temperature, package non-planarity should be less than 7 mils by the seating plane method to ensure less than 4 mils of warpage. The assembly processes can tolerate higher levels of coplanarity for die-up packages as warpage improves at reflow temperatures.It is recommended that the coplanarity be measured by the seating plane method.

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Impact of PBGA-ball-coplanarity on formation of solder joints

Cited by 11 publications

References 10 publications

Warpage prediction of fine pitch BGA by finite element analysis and shadow moiré technique

Warpage prediction of fine pitch BGA by finite element analysis and shadow moiré technique

A fast full-field 3D measurement system for BGA coplanarity inspection

Effect of substrate warpage on the second level assembly of advanced plastic ball grid array (PBGA) packages

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Impact of PBGA-ball-coplanarity on formation of solder joints

Cited by 11 publications

References 10 publications

Warpage prediction of fine pitch BGA by finite element analysis and shadow moir&#x00E9; technique

Warpage prediction of fine pitch BGA by finite element analysis and shadow moir&#x00E9; technique

A fast full-field 3D measurement system for BGA coplanarity inspection

Effect of substrate warpage on the second level assembly of advanced plastic ball grid array (PBGA) packages

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Product

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Warpage prediction of fine pitch BGA by finite element analysis and shadow moiré technique

Warpage prediction of fine pitch BGA by finite element analysis and shadow moiré technique