Design

“HDI Via Structures’ Effect on PCB Design Flexibility, Constraints and Cost”

Author: Happy Holden, happy_holden@mentor.com.

Abstract: The four common HDI via architectures are compared to determine how well each meets these diametrically opposed requirements. The four via architectures to be examined: drilled sequential lamination, staggered sequential microvia buildup, stacked sequential microvia buildup, and co-laminated any layer microvia buildup. The basis for comparison is looking at the complexity of the fabrication process and expected yields. DfM now focuses on yield management, and via structure is a major contributor to yield loss. This is contrasted to the resulting density, design constrains and I/Os per square inch achieved. Yield issues are more difficult to pin down because they are dependent on a number of variables and are largely statistically driven (i.e., the greater the occurrence of a certain configuration, the greater the likelihood of a board failure). This article proposes a simplification of the Wiebull Defect Density model as the basis for predicting first-pass yield of new HDI boards in manufacturing. (PCD&F, November 2007, pcdandf.com/cms/content/view/3930/95/)

Ball Bonding

“Gold Stud Bumping for High Density Flip Chip Interconnect”

Author: Daniel D. Evans, Jr., ddevans@bonders.com.

Abstract: Details a robust flip-chip solution for device-packaging companies using a gold-to-gold interconnect (GGI) process. The GGI process is a high precision interconnect method for flip chip die attach that uses the same thermosonic techniques used in gold wire bonding. Compared to gold wire bonding, GGI flip chip can reduce the device package area 50% to 70%, improves electrical performance, is a clean, Pb-free process and a cost-effective solution for low to medium I/O devices. (IMAPS Symposium, November 2007)

Soldering

“Reducing Power Consumption by Selecting Optimal Oven Recipes”

Authors: Abhinav Ajmera, Sreekanth Varma Penmatsa and Prof. S. Manian Ramkumar; smrmet@rit.edu.

Abstract: A study of optimal oven recipes for reduced power consumption for SnPb and Pb-free reflow soldering. Using a novel profiler, oven recipes were generated and selected for reduced power consumption and to measure the reduction in energy consumption by comparing energy consumed for an existing in-spec oven recipe for a production run, the equivalent energy consumed after changing the oven recipe to the settings suggested by the novel profiler. The work was conducted at three EMS sites. (Global SMT, November 2007, globalsmt.net/content/view/3128/131/)

Procurement

“The Triple-A Supply Chain”

Author: Prof. Haul Lee

Abstract: Rising demand and supply uncertainties require agility; shorter product and technology cycles need adaptability, and outsourcing and multiple supply chain partners – customers and suppliers from end to end – require alignment. Alignment, in this case, means win-win-win arrangements among all partners. Instead of company-to-company competition, the current era is one of supply chain to supply chain competition. (Harvard Business Review, October 2004; http://images.ed4.net/images/htdocs/hbsp/050117/AAA_SupplyChain.pdf)

How to Choose the Right EMS Provider for Medical Products Outsourcing

Author: Ed Evangelista; ed_evangelista@federalelec.com.

Abstract: Selecting the right EMS provider means determining who can provide a seamless and efficient extension of your operation while conforming to the critical requirements imposed by the FDA and other regulatory bodies. Details such issues as key process capabilities on which to evaluate suppliers; defining an outsourcing strategy; matching business profiles to prospective vendors; finding a personality “fit”; understanding your NPI strategy, and understanding total acquisition cost. Based on 20 years’ experience advising medical product OEMs to successfully execute supplier evaluations and selection processes. (federalelec.com/medicalpaper)

“An OEM Guideline for Selecting PCB Suppliers”

Authors: Renee Michalkiewicz, rmichalkiewicz@tracelabs.com

Abstract: Assessing a potential PCB supplier can be very simple to very complex, based on the resources available to the company. This guideline is aimed at smaller ODMs and OEMs. Steps to take to generate a list of potential suppliers are how to go about qualifying your supplier is outlined and discussed. Also, a few inexpensive microsections would add significantly to the “tour” approach of qualifying PCB suppliers. (PCD&F, December 2007, pcdandf.com/cms/content/view/4007/95/)

Circuits Assembly provides abstracts of papers from recent industry conferences and company white papers. With the amount of information increasing, our goal is to provide an added opportunity for readers to keep abreast of technology and business trends.