Coupling & Crosstalk: Testing the Supply Chain

change canstockphoto28381385_focalpoint_c350x350 Coupling & Crosstalk is my column in the MEPTEC Report. This column appears in the Spring 2018 edition on pages 8-9.

Electronic coupling is the transfer of energy from one circuit or medium to another. Sometimes it is intentional and sometimes not (crosstalk). I hope that this column, by mixing technology and general observations, is thought provoking and “couples” with your thinking. Most of the time I will stick to technology but occasional crosstalk diversions may deliver a message closer to home.

Testing the Supply Chain

Much the same as the world, test is not simply black or white but varying shades of grey and a jumble of colors. Test has continually responded to semiconductor technology challenges to provide the right solutions. As a result, the organizational placement and “supply chains” for test have rarely been Continue reading “Coupling & Crosstalk: Testing the Supply Chain”

BiTS Workshop – The Next 15 Years

Thanks to the BiTS Committee for the hard work to make this a great event!
Thanks to the BiTS Committee for the hard work to make this a great event!

Wow! The Burn-in and Test Strategy (BiTS) Workshop just turned 15! The world of semiconductors has certainly changed over the years. And the BiTS Workshop has kept up with what is “Now & Next” in the burn-in and test of packaged integrated circuits (ICs). These achievements were celebrated in style by the more than three hundred participants at the recently held 2014 BiTS Workshop in Mesa, Arizona.

“When the BiTS Workshop started in 2000, there were no Continue reading “BiTS Workshop – The Next 15 Years”

IEEE Semiconductor Wafer Test Workshop 2013

Ideal 3D Stacked Die Test - Ira Feldman - IEEE SWTW2013
Click image to download presentation

I had the pleasure of presenting “Ideal 3D Stacked Die Test” in Session Two “Industry Trends and Advanced Packaging Challenges” of the 23rd annual IEEE 
Semiconductor Wafer Test Workshop (SWTW) on Monday June 10, 2013.

Integrated circuits using 2.5D advanced packaging are shipping. 3D packaging with thru-silicon vias (TSV) has been demonstrated. “5.5D” packages may not be far behind. Probe card suppliers have made progress building interconnect technology for the micro-bump arrays. Standards committees have started defining IC interface standards and test access protocols.

But what does the Test Engineer and Management really want? What can they afford? What are the most likely scenarios? Factors that determine which test technology can support the desired test flow are examined. In particular, probe card technology for probing TSV bumps and potential usage models are reviewed.

Riding Off Into the Sunset – BiTS 2013

Sunset over Phoenix, Arizona during BiTS Workshop
Sunset over Phoenix, Arizona during BiTS Workshop

As the Burn-in & Test Strategies (BiTS) Workshop 2013 fades into the sunset (queue the music), here is a round-up of the highlights. There were gun fights in the corral as well as technical questions for the presenters. The saloon girls and gunfighters took an edge off of the “geek” factor. This year over three hundred fifty people come to the “Circle BiTS Ranch” (aka the Hilton in Mesa, Arizona) for the premier conference focused on what is new and next for semiconductor test tooling and strategy. Oh, did I mention that the theme this year was Western?

This was the 14th annual BiTS Workshop, which has achieved the perfect conference trifecta of Continue reading “Riding Off Into the Sunset – BiTS 2013”

IEEE Semiconductor Wafer Test Workshop 2012 – Session 8 (Wednesday)

Semiconductor wafer test workshop swtw sign 500x352

Here are the highlights from Session Eight “Probe Process and Metrology” of the 22nd annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Wednesday June 13, 2012.

Rob Marcelis (BE Precision Technology ‐ The Netherlands), “H3D Profiler for Contact Less Probe‐Card Inspection”:

Probe cards require inspection since they are consumables subject to wear. Changes in probe position or shape can damage the semiconductor devices they are testing. As probe cards increase in size and probe count, the probe cards themselves are becoming more expensive to test in terms of test time and complexity. Each new test system typically requires an expensive “motherboard” for the probe card metrology tool to simulate the mechanics of the tester and provide electrical interconnect to the card for electrical testing.

BE Precision Technology took a different approach by Continue reading “IEEE Semiconductor Wafer Test Workshop 2012 – Session 8 (Wednesday)”

IEEE Semiconductor Wafer Test Workshop 2012 – Session 7 (Tuesday)

Semiconductor wafer test workshop swtw sign 500x352

Here are the highlights from Session Seven “Fine Pitch Probing Challenges” of the 22nd annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Tuesday June 12, 2012.

Jose Horas (Intel Mobile Communications ‐ Germany), “28nm Mobile SoC Copper Pillar Probing Study”:

Intel Mobile Communications (IMC, previously Infineon Wireless) has started to switch from tin-silver (SnAg) solder bumps to copper pillars (CuP) with SnAg caps for attaching their die to packages. Since the bumps and pillars are formed on the wafer prior to testing of the devices the wafer probe process must accommodate both. CuP offer several advantages over SnAg bumps: tighter pitch (now at 120 µm and able to scale smaller versus 150 µm for SnAg bumps), lower substrate costs due to relaxed design rules, and lower assembly costs (easier to under fill).

The MicroProbe Apollo (vertical buckling beam) probe cards optimized for low force probing using 2.5 mil diameter probes were  Continue reading “IEEE Semiconductor Wafer Test Workshop 2012 – Session 7 (Tuesday)”

IEEE Semiconductor Wafer Test Workshop 2012 – Session 6 (Tuesday)

Here are the highlights from Session Six “Meet the Challenge” of the 22nd annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Tuesday June 12, 2012.

Robert Stampahar (SV Probe ‐ An Ellipsiz Company) and Wally Haley (Qualcomm), “Meeting the 1st Silicon: An Alternate Approach for Reducing Probe Card Cycles”:

Unlike other devices which can be tested in packaged form using a test socket, wafer level chip scale packages (WLCSP) rely completely on wafer probe cards for test. A load board with a test socket can usually be designed and fabricated quickly enough that the bring up and debug of new silicon designs is not delayed. When using a wafer probe card that contains a multilayer ceramic (MLC) or multilayer organic (MLO) space transformer, the delivery of the probe card is  Continue reading “IEEE Semiconductor Wafer Test Workshop 2012 – Session 6 (Tuesday)”

IEEE Semiconductor Wafer Test Workshop 2012 – Session 5 (Tuesday)

Semiconductor wafer test workshop swtw sign 500x352

Here are the highlights from Session Five “New Probe Card and Contact Technologies” of the 22nd annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Tuesday June 12, 2012.

Tsutomu Shoji (Japan Electronics Materials Corp. ‐ Japan) and Takashi Naito (Advantest ‐ Japan), “Full Wafer Contact Breakthrough with Ultra‐High Pin Count”:

Awarded Best Overall Presentation

As the number of probes on probe cards increase due to greater parallelism, driven by the desire for one touchdown testing and the future transition to 450 mm wafers, the total force required to probe a wafer increases if there is no reduction in the force per probe. This wafer prober chuck needs to apply the required force by pushing the wafer against the probe card typically held in place by the structure of the prober. With 200K probes on a 450 mm wafer each requiring 5 gF this is approximately equal to 1 ton (2205 lbF) of applied force. To reduce these force requirements wafer chuck and prober structure, Advantest and JEM have Continue reading “IEEE Semiconductor Wafer Test Workshop 2012 – Session 5 (Tuesday)”

IEEE Semiconductor Wafer Test Workshop 2012 – Session 4 (Monday)

Click image to download presentation

Here are the highlights from Session Four “New Contactor Technologies and RF PCB Design” of the 22nd annual IEEE 
Semiconductor Wafer Test Workshop (SWTW) from Monday June 11, 2012.

A last minute change to balance the schedule moved my paperThe Road to 450 mm Semiconductor Wafers” from the previous session:

Many believe that Gordon Moore in his famous 1965 paper “The Experts Look Ahead: Cramming More Components onto Integrated Circuits” that has become know as Moore’s Law, said that the number of transistors on a device would double every year (later revised to every two years). He did not say quite that. What he said was  Continue reading “IEEE Semiconductor Wafer Test Workshop 2012 – Session 4 (Monday)”

IEEE Semiconductor Wafer Test Workshop 2012 – Session 2 (Monday)

Semiconductor wafer test workshop swtw sign

Here are the highlights from Session Two “Optimizing Probe Depth Performance” of the 22nd annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Monday June 11, 2012.

Tommie Berry (FormFactor, Inc.), “Actual vs. Programmed Over Travel for Advanced Probe Cards”:

As the number of probes on a probe card increase, the total force required to compress these probes – know as probe force – is increasing. With high force the actual over travel (AOT) – also know as overdrive – of the probe is often significantly different than the programmed over travel (POT) programmed in the prober. Even though memory test engineers with very high probe count cards have Continue reading “IEEE Semiconductor Wafer Test Workshop 2012 – Session 2 (Monday)”

IEEE Semiconductor Wafer Test Workshop 2012 – Welcome & Session 1 (Monday)

Semiconductor wafer test workshop swtw sign 500x352

Here are the highlights from the Welcome and Session One “Process Improvements for HVM” of the 22nd annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Monday June 11, 2012.

Jerry Broz (SWTW general conference chair) started with several sets of numbers: SWTW attendance (up), semiconductor revenue and wafer statistics (problems). and probe card market (up). The problem with semiconductor statistics are  Continue reading “IEEE Semiconductor Wafer Test Workshop 2012 – Welcome & Session 1 (Monday)”

Two Conferences – Two Industries Challenged By Post PC Era

Tim Cook introducing Apple's latest iPad

The “Post Personal Computer” (Post PC) era became the hot topic when Tim Cook introduced the latest iPad last week. Yes, calling it a “revolution” is definitely hype that is part of Apple‘s Post PC marketing campaign. Hype aside, it is clear that there has been a marked shift in digital hardware for the consumption of content and communication. The PC – be it a Windows, Mac, or Linux based system – is no longer “the device”. It is now one of many devices including portable music players (dominated by iPods), smart phones (lead by iPhones and Android based systems), and tablets (dominated by iPads). The shift is large and the impact is huge. To understand how big, watch the first three minutes of Mr. Cook’s presentation. Then you will understand why Apple had the largest market capitalization of any US company in February – the numbers are staggering.

Even though many were surprised to learn that we are now “Post PC”, some of us who have been developing strategies for the electronic supply chain have Continue reading “Two Conferences – Two Industries Challenged By Post PC Era”

Silicon Valley Test Workshop – 2nd Year “Rocks”

2 5D? 3D? What? 3D IC Packaging - Ira Feldman
Click image to download presentation

Back for the second year (with a minor name change), the Silicon Valley Test Workshop is an unpolished gem. Looking past the rough edges (minor logistical issues), what really shines through is the interaction of the participants. This conference really has Continue reading “Silicon Valley Test Workshop – 2nd Year “Rocks””

Semiconductor Packaging: 2.5D, 3D, and Beyond!

MEPTEC's 2.5D, 3D and Beyond Packaging Conference

The MEPTEC2.5D, 3D and Beyond – Bringing 3D Integration to Packaging Mainstream” conference was a mixed-bag. Yes, it is always exciting to hear about new suppliers and progress. But it is disconcerting to realize that the price of progress is an ongoing burden on our industry’s supply chain.

Subramanian Iyer (IBM) and Theresa Sze (Oracle) started with Continue reading “Semiconductor Packaging: 2.5D, 3D, and Beyond!”