Thermoelastic Modeling of a PWB With Simulated Circuit Traces Subjected to Infrared Reflow Soldering With Experimental Validation

1999 ◽  
Vol 121 (4) ◽  
pp. 263-270 ◽  
Author(s):  
Y. Polsky ◽  
I. C. Ume
Keyword(s):  
Experimental Validation ◽  
Effective Properties ◽  
Experimental System ◽  
Thermal Gradients ◽  
Printed Wiring Board ◽  
Reflow Process ◽  
Reflow Soldering ◽  
Lamination Theory ◽  
Support Conditions ◽  
Wiring Board

A bare, four copper layer printed wiring board with simple trace patterns was built for modeling and experimental validation purposes. In-plane elastic properties of the core materials in the board were measured as a function of temperature. Thermoelastic lamination theory was utilized to predict the warpage of the board when subjected to an infrared reflow process, with emphasis on studying the influence of thermal gradients through the board, its support conditions and CTE differential on the warpage process. Board layers with traces were approximated with quasi-homogeneous effective properties obtained using micromechanics theory. An experimental system that employs the shadow moird technique in a simulated infrared reflow environment was used to evaluate the warpage for comparison to modeled results.

Comparison of First-Order Shear and Plane Strain Assumptions in Warpage Prediction of Simply Supported Printed Wiring Boards

2000 ◽  
Vol 123 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Yarom Polsky ◽  
I. Charles Ume
Keyword(s):  
Plane Strain ◽  
Plate Theory ◽  
Shear Deformation Theory ◽  
Transverse Load ◽  
Transverse Shear Strain ◽  
Printed Wiring Board ◽  
Simply Supported ◽  
First Order ◽  
Support Conditions ◽  
Wiring Board

The influence of transverse shear strain in the lamination theory modeling of Printed Wiring Board (PWB) deflection due to support conditions was examined. The in-plane mechanical properties of the core materials of a commercial PWB were measured as a function of temperature. Classical laminated plate theory and first-order shear deformation theory solutions for the out-of-plane deflection of a bare board configuration with two opposite edges simply supported and the remaining edges free were obtained. The weight of the board was approximated as a distributed transverse load. The effect of material property decrease with temperature and FR-4 layer thickness were examined to compare first-order shear and plane strain assumptions for the predicted warpage.

System for Real-Time Measurement of Thermally Induced PWB/PWA Warpage

1997 ◽  
Vol 119 (1) ◽  
pp. 1-7 ◽  
Author(s):  
M. R. Stiteler ◽  
I. C. Ume
Keyword(s):  
Real Time ◽  
Measurement System ◽  
Printed Wiring Board ◽  
Reflow Soldering ◽  
Thermally Induced ◽  
Operational Conditions ◽  
Soldering Process ◽  
Before And After ◽  
On Line ◽  
Wiring Board

An automated on-line warpage measurement system for printed wiring board assemblies (PWBAs) has been developed. The system is capable of simulating an infrared reflow soldering process and performing real-time PWBA warpage measurements using the shadow moire´ technique. The system can be used to characterize the warpage behavior of virtually any PWBA during infrared soldering processes as well as during operational conditions. Using this system, warpage of PWB test vehicles was measured during simulated infrared reflow soldering. The measurement results and the measurement system will be presented. The measured warpage varied significantly during reflow soldering from that observed both before and after reflow. These results help us to understand how the board deforms at every stage of the reflow process.

scholarly journals Evaluation of Warp of Printed Wiring Board under Reflow Soldering.

1997 ◽  
Vol 12 (6) ◽  
pp. 444-447
Author(s):  
Nobutaka ITOH ◽  
Mami NAGATAKE ◽  
Osamu IDO ◽  
Hitoshi KANEKO ◽  
Masaki OHNO
Keyword(s):  
Printed Wiring Board ◽  
Reflow Soldering ◽  
Wiring Board

A Novel Projection Moiré System for Measuring PWBA Warpage Using Simulated Optimized Convective Reflow Process

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Reinhard E. Powell ◽  
I. Charles Ume
Keyword(s):  
Measurement System ◽  
Flip Chip ◽  
Active Contours ◽  
Printed Wiring Board ◽  
Reflow Process ◽  
Shadow Moire ◽  
Shadow Moiré ◽  
Plastic Ball ◽  
Wiring Board ◽  
Projection Moire

The shadow moiré technique is a widely used method of measuring printed wiring board (PWB) warpage. It has a high resolution, high accuracy, and is suitable for use in an online environment. The shortcoming of the shadow moiré technique is that it cannot be used to measure PWBs populated with chip packages. In this paper, a novel warpage measurement system based on the projection moiré technique is presented. The system can be used to measure bare PWBs, as well as PWBs populated with chip packages. In order to use the projection moiré system to accurately determine the warpage of PWBs and chip packages separately, an automated chip package detection algorithm based on active contours is utilized. Unlike the shadow moiré technique, which uses a glass grating, the projection moiré technique uses a virtual grating. The virtual grating sizes can be adjusted, making it versatile for measuring various PWB and chip package sizes. Without the glass grating, which is a substantial heat inertia, the PWB/printed wiring board assembly (PWBA) sample can be heated more evenly during the thermal process. The projection moiré system described in this paper can also be used to measure the warpage of PWBs/PWBAs/chip packages during convective reflow processes. In this paper, the characteristics of the projection moiré warpage measurement system will be described. In addition, the system will be used to measure the warpage of a PWB and plastic ball grid array packages during a Lee optimized convective reflow process (Lee, N.-C., 2002, Reflow Soldering Processes and Troubleshooting SMT, BGA, CSP, and Flip Chip Technologies, Butterworth-Heinemann, MA). It is concluded that this projection moiré warpage measurement system is a powerful tool to study the warpage of populated PWBs during convective reflow processes.

Toward Manufacturing Low-Cost, Large-Area Electronics

MRS Bulletin ◽  
2006 ◽  
Vol 31 (6) ◽  
pp. 471-475 ◽  
Author(s):  
Marc Chason ◽  
Daniel R. Gamota ◽  
Paul W. Brazis ◽  
Krishna Kalyanasundaram ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Printed Electronics ◽  
Low Cost ◽  
Consumer Products ◽  
Electronic Systems ◽  
Printed Wiring Board ◽  
Large Area ◽  
Active Devices ◽  
Materials Research ◽  
Wiring Board ◽  
Large Area Electronics

AbstractDevelopments originally targeted toward economical manufacturing of telecommunications products have planted the seeds for new opportunities such as low-cost, large-area electronics based on printing technologies. Organic-based materials systems for printed wiring board (PWB) construction have opened up unique opportunities for materials research in the fabrication of modular electronic systems.The realization of successful consumer products has been driven by materials developments that expand PWB functionality through embedded passive components, novel MEMS structures (e.g., meso-MEMS, in which the PWB-based structures are at the milliscale instead of the microscale), and microfluidics within the PWB. Furthermore, materials research is opening up a new world of printed electronics technology, where active devices are being realized through the convergence of printing technologies and microelectronics.

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