Component Layout

“PCB Design and Assembly for Flip-Chip and Die Size CSP”
Author: Vern Solberg; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
Abstract: This paper outlines the basic elements furnished in the newly released IPC-7094, Design and Assembly Process Implementation for Flip-Chip and Die Size Components, providing a comparison of existing and emerging wafer-level and chip-size package methodologies. The focus is on the effect of PCB design and assembly of bare die or die-size components in an uncased or minimally cased format. (IPC Apex, April 2010)

Solder Joint Defects

“Telecommunications Case Studies Address Head-in-Pillow (HnP) Defects and Mitigation through Assembly Process Modifications and Control”
Authors: Russell Nowland, Richard Coyle, Peter Read and George Wenger; russell.nowland@
alcatel-lucent.com.
Abstract: This paper discusses several contributing factors to the head-in-pillow defects and techniques to control them. The case studies presented show that process control can mitigate HnP defects, but may not be successful for some severe examples of HnP defects. The case studies include reviewing paste printing modifications, solder paste DoE, shadow moiré scans on several problematic BGA packages, effectiveness of x-ray inspection, and cross-section analysis of failed HnP solder joints. Together, these case studies show that BGA package warpage is a major contributor, but HnP defects can occur when almost any of the assembly process parameters deviate from acceptable practices. (IPC Apex, April 2010)

Solder Joint Inspection

“Robust Automated Void Detection in Solder Balls and Joints”
Authors: Asaad F. Said, Bonnie L. Bennett, Lina J. Karam and Jeff Pettinato; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
Abstract: This paper proposes a robust, accurate, and automatic void detection algorithm. The proposed method is able to detect voids with different sizes inside the solder balls, including the ones that are occluded by board components and under different brightness conditions. The proposed method consists of segmenting individual balls, extracting occluded balls, and segmenting voids inside the solder balls. Segmentation of the individual balls is achieved by using the proposed histogram and morphological-based segmentation method. (IPC Apex, April 2010)