Here are the highlights from the Welcome and Session One “Process Improvements for HVM” of the 22nd annual IEEESemiconductor Wafer Test Workshop (SWTW) from Monday June 11, 2012.
As the final presenter at this week’s IEEESemiconductor Wafer Test Workshop (SWTW), I outlined how critical it is to understand the true cost of a product’s architecture in “Probe Card Cost Drivers from Architecture to Zero Defects“. Without a proper understanding of these costs – especially for fully custom high technology products such as wafer test probe cards – it is impossible to maintain a sufficient gross margin. Gross margin is essential to maintain the health of a company and to fund the research & development required for innovation.
Many companies in the semiconductor test market have entered a period that Steve Newberry identified in his 2008 speech “Semiconductor Industry Trends: The Era of Profitless Prosperity?” that parallels the aluminum industry in the 1970’s. And without the means to fund innovation, companies have no future especially when faced with the double threat of Moore’s Law – increasingly harder technical requirements delivered at lower cost.
Yes, there were a few in the audience who appeared pleased since they are confident that their products are on the right path. There were others who may have been upset based upon their company’s direction. I would argue that a proper diagnosis – regardless of how disturbing – is essential to drive the proper cure.
There is plenty of opportunity in the test market and reasons for optimism. The key to long term prosperity is to really understand the fundamentals of the business and not be blinded by the technology.
I thank those who stayed for the entire conference and welcome your thoughts below. And I will be posting more about the conference (including my summaries) in the next few weeks.
Senthil Theppakuttai, SV Probe, “Probing Assessment on Fine Pitch Copper Pillar Solder Bumps”:
Flip chips devices are shrinking from 150 µm to 35 µm pitch interconnect. At 150 µm pitch solder balls formed by deposition or electroplating, and stud bumping are typically found. However at tighter pitches down to 35 µm, copper (Cu) pillars with solder caps are the preferred termination. The copper pillars solve electro-migration issues and mechanical/thermal (CTE) mismatch found with solder balls and stud bumping. Continue reading “IEEE Semiconductor Wafer Test Workshop – Area Array Probing – Session Eight (Wednesday)”
Balancing test coverage versus test cost. What does a test failure mean? Value of yield increase
… and how it impacts your bottom line!
A poorly implemented semiconductor test cell may pass integrated circuit (IC) parts that are either defective or have marginal performance. They can cause the electronic devices in which they will be assembled to either malfunction or completely fail. However, two other conditions require evaluation. Having false negative test “escapes” is expensive in terms of final product test failures, warranty costs, customer dissatisfaction, etc. In turn, the false positive test escapes needs to be balanced against the cost of false negative failures where otherwise good parts fail the tests and are discarded. Test engineers, product managers, quality engineers, and operational managers needs to make either implicit or explicit decisions as to the proper balance in adjusting the test limits. The goal is to cost effectively approach “zero defects” without “throwing out the baby with the bath water”.
A test process generally categorizes the item or device being tested as “pass” or “fail”. Sometimes passing devices are graded (typically by speed or other desired quality) and failing devices are often grouped by failure mode. “Coverage” is how well a particular test process measures the functionality and specifications of a given device. If every feature and specification is tested then it is said to have 100% test coverage. However, exhaustive testing is usually expensive due to long test times which translates in to operational costs including the depreciation of the test system and greater test setup complexity (equipment and development cost). Sometimes complete coverage is not possible or practical so there needs to be a trade-off between coverage and cost.
High Technology Business Development - Ira Feldman 