Coupling & Crosstalk: Trust your Paranoia!

Coupling & Crosstalk is my column in the MEPTEC Report. This column appears in the Winter 2019 edition on pages 11-12.

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.

Trust Your Paranoia!

President Ronald Reagan’s use of the Russian proverb “Doveryai, no proveryai” was the perfect soundbite to describe the 1987 Intermediate-Range Nuclear Forces Treaty. What does this and Andy Grove’s “only the paranoid survive” have to do with semiconductors? Continue reading “Coupling & Crosstalk: Trust your Paranoia!”

Coupling & Crosstalk: KGD Redux?

Coupling & Crosstalk is my column in the MEPTEC Report. This column appears in the Fall 2019 edition on pages 9-10.

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.

KGD Redux?

Known Good Die (KGD) – Is this a case of “everything old is new again” or acid reflux from a mature semiconductor industry? Today there is a greater need than ever to know that a given semiconductor die is good before proceeding to package it. This particular quest for the holy grail has provided plenty of Continue reading “Coupling & Crosstalk: KGD Redux?”

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.

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”

Semiconductor Wafer Test Workshop 2015 Presentation – Are You Really Going To Package That?

Are You Really Going To Package That? - Ira Feldman and Debbora Ahlgren - SW Test 2015 — Click image to download presentation

I had the pleasure of presenting “Are You Really Going To Package That?” at the 25th annual Semiconductor Wafer Test Workshop (SW Test / SWTW) on Tuesday June 9, 2015. Debbora Ahlgren and I took this opportunity to step back and look at how old paradigms in test-cell integration may lead to suboptimal solutions.

In an effort to reduce the cost-of-test (COT), a number of customers are increasing the parallelism of logic wafer probe cards. However, due to the complexity such as pitch and number of probes, the pricing for these cards is reaching astronomical levels. We do not believe this trend is sustainable, let alone logical. The presentation suggested examples of alternative solutions. It is clear that critical solutions need to be optimized at the test cell, factory, and supply chain level not just at the consumable (probe card) level.

IEEE Semiconductor Wafer Test Workshop 2014 Presentation

International Technology Roadmap for Semiconductors (ITRS) - Ira Feldman - IEEE SWTW2014 — Click image to download presentation

At the 24th annual IEEE
Semiconductor Wafer Test Workshop (SWTW) on Wednesday June 11, 2014,
I had the pleasure of presenting “International Technology Roadmap for Semiconductors”. This presentation was co-authored with Dave Armstrong (Advantest) and Marc Loranger (FormFactor).

For the last fifteen years the International Technology Roadmap for Semiconductors (ITRS) has been looking fifteen years into the future. Based upon technology requirements and other inputs, ranging from the gate size of transistors to advanced packaging technology, the Test and Test Equipment Technical Working Group (Test TWG) has worked to develop the requirements for test technology and equipment.

The Test TWG is over seventy volunteers with deep technical expertise in test from around the world and from every sized company – Fortune 100 to individual consultants – and every type of company – semiconductor independent device manufacturer (IDM), fabless semiconductor, foundry, outsourced assembly and test (OSAT), automated test equipment (ATE) suppliers, prober, probe card, socket, handler, and more. Through Continue reading “IEEE Semiconductor Wafer Test Workshop 2014 Presentation”

BiTS Workshop – The Next 15 Years

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”

Chip Scale Review: The Three Most Important Words for 3D ICs?

Below is my event summary recently published in Chip Scale Review Tech Monthly:

Cost! Cost! Cost! are the three most important words for 3D semiconductors.

Just like the real estate mantra “location, location, location”, if you don’t have a solution to the cost issues nothing else matters for 2.5/3D integrated circuit (IC) integration and packaging. It is true that, Xilinx is shipping “production” quantities of 2.5D parts and others have sampled 3D parts. However, there are plenty of technical challenges yet to be solved to make 2.5/3D practical in volume production at reasonable cost and yield.

Every presenter at the 3D Architectures for Semiconductor Integration and Packaging symposium and conference stressed cost as a major concern, requirement, or feature. Over the ten years the discussion at this conference, organized by RTI International Technology Venture Forum, has moved from Continue reading “Chip Scale Review: The Three Most Important Words for 3D ICs?”

Coupling & Crosstalk: Name Calling

Coupling & Crosstalk is my column in the MEPTEC Report. This column appears in the Summer 2013 edition on pages 13-14.

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.

Name Calling

What’s in a name? A lot! A name itself might not mean much but it can trigger expectations and stereotypes. In the United States we have red states and blue states depending on which political party has the majority vote. Similarly, when someone labels themselves on the basis of their political party affiliation (Republican, Democrat, Libertarian, Independent, etc.) others Continue reading “Coupling & Crosstalk: Name Calling”

Riding Off Into the Sunset – BiTS 2013

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”

SEMI ISS: Sense of Scale

Intel shows first fully patterned 450 mm semiconductor wafer at SEMI ISS 2013

Attending the SEMI Industry Strategy Symposium (ISS) is like drinking from a fire hose with the additional risk of whiplash. Don’t get me wrong, it is an exquisite fire hose but sometimes the data presented can be overwhelming at this conference of semiconductor supply chain executives. The majority of the attendees and presenters are executives from the SEMI member companies that develop the equipment, materials, processes, and technology used to build, test, and package semiconductors. And the executives present from the semiconductor manufacturers are typically the “end customers”.

The greatest value of SEMI ISS, beyond the networking, is the strategic overview of the entire semiconductor ecosystem. What are the market drivers, the technology needed, and the roadmap status of this industry? It is true that we all know where we need to head courtesy of Moore’s Law and the International Technology Roadmap for Semiconductors which attempts to keep us on that trajectory. The pressure of consumers ~~needing~~ wanting greater functionality at lower costs is relentless. Much of the technological detail of this ecosystem is addressed in a myriad of other forums throughout the year. ISS ties these technical requirements, development needs, and business needs back to the strategic direction and desires of the global marketplace.

The whiplash comes from Continue reading “SEMI ISS: Sense of Scale”

Chip Scale Review: News from 3-D Architectures for Semiconductor Integration and Packaging

My event summary recently published in Chip Scale Review Tech Monthly:

Is 3D semiconductor packaging really the Lego of the integrated circuit (IC) world? It is a great analogy for the range of possible solutions and flexibility provided by different flavors of 3D packaging (2.5D on interposer, 3D, 5.5D, etc.) and “colors” (homogenous and heterogeneous) of die stacks. Plenty of pictures of Legos and scanning electron microscope (SEM) images were shown last week at the RTI International Technology Venture Forum symposium and conference “3-D Architectures for Semiconductor Integration and Packaging”. Presenters clearly articulated the great promise of what could be built with 3D packaging. At the same time, progress towards solving the multitude of challenges to make this technology as pervasive, if not as easy to use and fun, as Legos was discussed.

The challenges span Continue reading “Chip Scale Review: News from 3-D Architectures for Semiconductor Integration and Packaging”

MEMS Testing and Reliability 2012 – Session 3

Can reliability and production testing keep pace with the explosive growth in microelectromechanical system (MEMS) based product volumes? Soon it will be the rare consumer product that does not include a MEMS device bringing us closer to the possibility of a $1 trillion MEMS market. In order to achieve greater adoption of the technology, cost and quality goals will need to be met through testing and reliability. This was the focus of the MEMS Testing and Reliability 2012 conference produced by MEMS Journal and MicroElectronics Packaging and Test Council (MEPTEC).

Session 3

Pavan Gupta (Vice President of Operations, SiTime) provided a cautionary tale in “Packaging and Reliability Qualification of MEMS Resonator Devices”. Historically many MEMS companies have failed to start the device and package co-design as early as possible even though packaging was upwards of 80% of the product cost. [Perhaps they aren’t really using a concurrent engineering methodology?] Even though the cost of packaging has dropped significantly, the complexities and risks related to packaging remain high.

There are many challenges related to MEMS packaging since without a reliable and qualified package, it is not possible for one’s customers to easily and confidently integrate a MEMS product into their end product. In SiTime’s case they had a double challenge of Continue reading “MEMS Testing and Reliability 2012 – Session 3”

MEMS Testing and Reliability 2012 – Session 2

Session 2

Mårten Vrånes (Director of Consulting Services, MEMS Journal) in “A Test-centric Approach to MEMS ASIC Development” discussed alternatives to the traditional co-design of the MEMS element and application specific integrated circuit (ASIC). As many MEMS devices require an ASIC to control and/or sense the MEMS element the most logical approach is to design both parts in parallel. However the scope of such a development effort is often beyond the resources – both in terms of talent and funding – for many companies especially startups.

Mr. Vrånes started with the challenges and pitfalls of ASIC development for MEMS devices. There are challenges regardless of Continue reading “MEMS Testing and Reliability 2012 – Session 2”

MEMS Testing and Reliability 2012 – Session 1

It was my pleasure to attend the MEMS Testing and Reliability 2012 conference to see the considerable progress made in these areas as microelectromechanical system (MEMS) based product volumes accelerate. We may soon get to the point where it will be the rare consumer product that does not include a MEMS device bringing us closer to the possibility of a $1 trillion MEMS market. But in order to achieve greater adoption of the technology, cost and quality goals will need to be met through testing and reliability, the focus of this conference produced by MEMS Journal and MicroElectronics Packaging and Test Council (MEPTEC).

Session 1

Mario Correa (MEMS Test Engineering Manager of Fairchild Semiconductor) started with “Evolution of MEMS Test Solutions” reviewing how test equipment and processes have evolved from the 1960’s to today. There have been major changes to test methods developed for non-MEMS sensors first used with military and aerospace MEMS sensors in the late 1960’s where the annual volume was measured in thousands of units to those used today for over three billion units shipped yearly to the consumer electronics market. It has been a challenge keeping up with the high triple digit growth rates from 2009 to 2012 including gyroscopes +189%, microphones +347%, and digital compasses +778%. MEMS accelerometers grew “only” +78% during this period. (Growth data per Yole)

These changes include Continue reading “MEMS Testing and Reliability 2012 – Session 1”

IEEE Semiconductor Wafer Test Workshop 2012 – Session 9 (Wednesday)

Semiconductor wafer test workshop swtw sign 500x352

Here are the highlights from Session Nine “Productivity / Cost of Ownership (COO)” of the 22nd annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Wednesday June 13, 2012.

Teruyuki Kitagawa (Nomura Plating, Co., Ltd. – Japan), “Unique Characteristics of the Novel Carbonaceous Film with High Electrical Conductivity and Ultra High Hardness for Semiconductor Test Probes”:

In a follow-up to last year’s presentation, improvements to Nomura’s carbonaceous film were discussed. The film has a much higher hardness (Hv 4000) than palladium (Pd, Hv 350 ~ 400) or even diamond-like carbon (DLC, Hv 1000 ~ 2000) which provides wear resistance and acts as a self cleaning surface. The significant improvement since last year is Continue reading “IEEE Semiconductor Wafer Test Workshop 2012 – Session 9 (Wednesday)”

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 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)

Road-to-450-mm-Semiconductor-Wafers-Ira-Feldman-SWTW-2012.png — 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 paper “The 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 3 (Monday)

Semiconductor wafer test workshop swtw sign

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

Larry Levy (FormFactor, Inc.), “Is Parametric Testing About To Enter a Period of Growth and Innovation?”:

Upwards of one thousand facilities perform parametric wafer testing (based on 2009 market data) with over a third of these using obsolete test equipment. There have been no really new testers in several years – Agilent still has their 40xx series and Keithley has their S530 tester. And several companies have exited the market and some companies (including Keithley) are no longer supporting older models of testers. Since parametric testing remains an essential process, this has forced a high number of these facilities to use obsolete equipment or find other approaches. A few companies are going as far as using an Advantest 93000, a significantly more expensive and highly sophisticated digital tester, for parametric test. [Updated to clarify Keithley’s status.]

Parametric testing can be divided into three categories: in-line, end of line (EOL), and quality and reliability. In-line testing is Continue reading “IEEE Semiconductor Wafer Test Workshop 2012 – Session 3 (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)”

IEEE Semiconductor Wafer Test Workshop 2012 – Opening Session & Keynote (Sunday)

This year’s IEEE Semiconductor Wafer Test Workshop started on Sunday June 10th with a pleasant surprise. Due to a welcomed but unexpected wave of seventy walk-in registrations, there was insufficient seating at the opening dinner. Thankfully the hotel staff quickly adjusted to accommodate these additional guests. Attendance and interest in this year’s workshop was clearly up.

Jerry Broz, general conference chair, welcomed everyone with a brief overview and presented prizes for the first annual golf tournament. We then quickly proceeded with business as Matt Nowak (Senior Director, Advanced Technology, Qualcomm CDMA Technologies) provided the keynote “Emerging High Density 3D Through Silicon Stacking (TSS) – What’s Next?” Mr. Nowak discussed the increased amount of hype within the 3D semiconductor packaging market in the last year with everyone announcing something. And Thru Silicon Vias (TSVs) technology has already been in high volume production for image sensors for several years now but at a significantly lower density than for 3D packaging.

Why the great interest recently in 3D packaging using TSVs today? Three simple reasons: Continue reading “IEEE Semiconductor Wafer Test Workshop 2012 – Opening Session & Keynote (Sunday)”

Thinking Big: $1 Trillion MEMS Market – Part 2

Part 1 described Janusz Bryzek‘s ambitious goal of a $1 trillion market for microelectromechanical systems (MEMS) that was the focus of the MicroElectronics Packaging and Test Council (MEPTEC) 10th annual MEMS Technology Symposium. In addition, sensor swarms, road mapping and market numbers were covered. Challenges, example applications, and key takeaways are discussed here along with a final score card on the $1 T market.

Continue reading “Thinking Big: $1 Trillion MEMS Market – Part 2”

Thinking Big: $1 Trillion MEMS Market – Part 1

Usual business advice includes thinking big to win big. Some organizations create Big Hairy Audacious Goals. Others like to find new markets that are underserved and grow to be number one. The semiconductor industry has Moore’s Law – the premise that the minimum cost point is achieved by doubling the number of transistors per chip every two years – driving it forward for almost fifty years.

Janusz Bryzek set a dramatic and ambitious goal of $1 trillion sales for the microelectromechanical systems (MEMS) market in 2022. Even though the MEMS market is expected to have “only” $12 billion in revenue in 2012, he isn’t being called a fool. Having cofounded eight seminal Silicon Valley MEMS companies and currently the Vice President of MEMS Development at Fairchild Semiconductor (which recently acquired his last company), Janusz is taken quite seriously.

Yes, at last week’s MicroElectronics Packaging and Test Council (MEPTEC) 10th annual MEMS Technology Symposium there were some who Continue reading “Thinking Big: $1 Trillion MEMS Market – Part 1”

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 MEPTEC “2.5D, 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!”

IEEE Semiconductor Wafer Test Workshop – Spring Pin Probing – Session Five (Tuesday)

Here are the highlights from Session Five – “Spring Pin Probing” of the 21st annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Tuesday June 14, 2011.

Brandon Mair, Texas Instruments, “WSP-Wafer Socket Probe for Flip Chip Applications“:

Wafer socket probe (WSP) technology has demonstrated better physical and electrical performance and lower cost of ownership (COO) than traditional vertical probe cards for testing wafer level chip scale packages (WLCSP) at 0.4 mm (400 µm) pitch. These WSP probe heads are typically built Continue reading “IEEE Semiconductor Wafer Test Workshop – Spring Pin Probing – Session Five (Tuesday)”

IEEE Semiconductor Wafer Test Workshop – High Performance Probing – Session Four (Monday)

Here are the highlights from Session Four – “High Performance Probing” of the 21st annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Monday June 13, 2011.

Bob Davis, Rudolph Technologies, “Testing Probe Cards That Contain Complex Circuitry“:

Over time, probe cards have increased in complexity from simple wire cantilever probes to those including passive components and digital control circuits. Some of these digital control circuits may even contain state based logic. At the same time the physical complexity of probe cards have increased in probe and channel counts, probe density, and total probe force. As a result, Continue reading “IEEE Semiconductor Wafer Test Workshop – High Performance Probing – Session Four (Monday)”

IEEE Semiconductor Wafer Test Workshop – Power Probing – Session Three (Monday)

Here are the highlights from Session Three – “Power Probing” of the 21st annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Monday June 13, 2011.

Michael Huebner, FormFactor, “A Hot Topic: Current Carrying Capacity, Tip Melting and Arcing”:

Power consumption per dynamic random-access memory (DRAM) is increasing to as high as 400 mA or more under normal test conditions. At the same time the number of DRAMs being tested in parallel – and sharing the same power supply – is increasing. Therefore, the risk of current damage to probes is increasing.

Two distinct, but related concerns are Continue reading “IEEE Semiconductor Wafer Test Workshop – Power Probing – Session Three (Monday)”

IEEE Semiconductor Wafer Test Workshop – Optimization / Process Analysis – Session Two (Monday)

Here are the highlights from Session Two – “Optimization / Process Analysis” of the 21st annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Monday June 13, 2011.

Steven Ortiz, Avago, “Probe to Pad Placement Error Correction for Wafer Level S-Parameter Measurements”:

Avago’s film bulk acoustic resonators (FBAR) technology usage is being expanded from filters to include oscillators. The example oscillator discussed operates at a 1.5 GHz resonant frequency with a Quality (Q) factor ranging from one thousand to several thousand and a one year aging specification of less than 25 ppm.

These devices are extremely difficult to test due to their precision and small size (not much larger than the two device pads). The drift specification is the hardest to measure. Since it is generally desirable to have at least 10x measurement capability, the drift measurement requires approximately 2.5 ppm of tester performance, i.e. 3.75 KHz accuracy at 1.5 GHz. They use Continue reading “IEEE Semiconductor Wafer Test Workshop – Optimization / Process Analysis – Session Two (Monday)”

IEEE Semiconductor Wafer Test Workshop – Probe Challenges – Session One (Monday)

Here are the highlights from Session One – “Probe Challenges” of the 21st annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Monday June 13, 2011.

Stevan Hunter, ON Semiconductor, “Use of Harsh Wafer Probing to Evaluate Various Bond Pad Structures”:

Recent product needs such as bond [pads] over active circuitry (BOAC), the use of copper (Cu) wire bonding, increased wafer probe touch downs (as many as 6 TDs), and the desire for greater device reliability has driven the need for more robust bond pads to survive wafer probing.

One method for checking for damage to the device from the probing process is via the “Cratering Test”. They etch off the top aluminum (Al) metallization layer of the pad to visually inspect for damage in the underlying titanium-nickel (TiN) barrier metal layer. If there is a problem they can spot a “crater” in the metal. They continue etching to remove the TiN layer to look for additional damage in the layer(s) below.

Continue reading “IEEE Semiconductor Wafer Test Workshop – Probe Challenges – Session One (Monday)”

IEEE Semiconductor Wafer Test Workshop – Opening Session & Keynote (Sunday)

On Sunday evening June 12th, 2011 Jerry Broz, the general conference chair, opened the IEEE Semiconductor Wafer Test Workshop welcoming us to the 21st year with a combined total attendance of over 5,000. He also briefly highlighted the positives in recent market trend data from the Semiconductor Industry Association (SIA) and VLSIresearch.

Dr. William Chen, Senior Technical Advisor, ASE Group, provided the keynote presentation “Backend to the Front Line”:

Dr. Chen started with Continue reading “IEEE Semiconductor Wafer Test Workshop – Opening Session & Keynote (Sunday)”

Probe Card Cost Drivers from Architecture to Zero Defects

Click to download presentation — Click image to download presentation

As the final presenter at this week’s IEEE Semiconductor 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.

Silicon Valley Test Conference – Something New & Overdue

Starting off something new is often challenging and difficult with many unknowns. Kudos to Nick Langston for creating the Silicon Valley Test Conference that was held last week. (November 8 & 9, 2010) It was the first test conference to actually take place in Silicon Valley. And yes there were some minor “bugs” like registration delays and a no-show by the audio visual contractor that should be solved in next year’s Rev 2.0. Even with a few rough edges, the quality of the presentations and the exhibitors shined through to make this a success.

The conference opened with an excellent keynote address by well-known industry expert Continue reading “Silicon Valley Test Conference – Something New & Overdue”

How to re-FORM or refill a fab

Fill Your Fab To Make Money — Fill 'er Up To Make Money

I usually try to ignore items that are unattributed, however a recent blog posting in the ElectroIQ blog “How To Fix FORM” caught my attention. It is true that FormFactor’s current difficulties are being discussed widely. However, the simplistic analysis and suggestions of this unknown “industry insider” need a reality check. The writer gets some of the overall problems right but may be missing the boat on the solutions.

Here are the supposed anonymous industry insider’s suggested fixes:

Continue reading “How to re-FORM or refill a fab”

Probe Cards & Dart Boards

The wildly varying projections for the semiconductor market in general and the wafer probe market in specific makes me believe that many analysts are simply torn between reporting their tea leaf readings and the scores on their dartboard. A hopefully more reliable source is VLSI Research and their annual probe market survey is eagerly anticipated every spring. One may argue about methodology but on the whole they do an excellent job of painting a comprehensive picture.

Their optimistic forecast is heartening but increased sales volume doesn’t always translate into profits and downturns when they occur can be fatal. Do you prepare for growth like a hare or a tortoise? Do you build excess capacity (“Field of Dreams“), take and fulfill new orders with lots of overtime and temporary workers, or do you forgo new business that bears high incremental start-up costs?

Continue reading “Probe Cards & Dart Boards”

SEMICON West: What a difference a year makes

Last week I was very busy visiting the combined SEMICON West and Intersolar North America trade shows in San Francisco. I had numerous meetings in addition to visiting the show floors and attending the excellent presentations. Based upon the lackluster show last year – I’ve heard some use “abysmal” to describe it – I almost hesitated to attend.

I’m happy to report that this year’s show was significantly better with a much more positive attitude and energy. SEMI’s preliminary attendance figure (for the combined show) is 29,461 which is up 32% from last year’s 17,048 verified attendance. This is significantly higher than both organizers expected. Intersolar had expected 1,600 visitors but had over twice as many. (The final numbers will be out in about two weeks in the “Post Show” report.)

Having attended for more than 15 years, Continue reading “SEMICON West: What a difference a year makes”

IEEE Semiconductor Wafer Test Workshop – Challenges of RF Probing – Session Nine (Wednesday)

Here are the highlights from Session Nine – Challenges of RF Probing of the 20th annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Wednesday June 9th.

Ellis Huang, MPI Corporation, “Novel Vertical Probe Card Solution for Multi-DUTs and RF Device on 3 GHz Applications”:

This project was done with UMC using MPI’s VPC vertical probe technology to test Bluetooth modules at 2.45 GHz.

In order to provide a 50 ohm signal as close to the device under test (DUT) as possible, they added dummy ground pins to the probe head around critical signal pins. Even though these signal pins already had adjacent ground pads that were probed on the device, these dummy pins (probes) were positioned closer to the signal pin thereby maintaining the 50 ohm impedance. The dummy pins are connected to other grounds via the copper flex circuit on the space transformer.
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IEEE Semiconductor Wafer Test Workshop – Area Array Probing – Session Eight (Wednesday)

Here are the highlights from Session Eight – Area Array Probing of the 20th annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Wednesday June 9th.

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.
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IEEE Semiconductor Wafer Test Workshop – Probe Potpourri – Session Seven (Tuesday)

Here are the highlights from Session Seven – Probe Potpourri of the 20th annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Tuesday June 8th.

Boyd Daniels, Texas Instruments, “Very Low Cost Probe Cards – A Two Piece Approach”:

For their “catalog” parts – medium complexity, low volume, and medium number of devices – historically it has been cheaper to blind package (i.e. skip wafer test prior to packaging) and take the yield loss at package test. The main issue is the high initial cost and maintenance of probe cards is too high relative to the volume of parts to be tested.
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IEEE Semiconductor Wafer Test Workshop – Parametric / Scribeline Probing – Session Six (Tuesday)

Here are the highlights from Session Five – Signal Integrity of the 20th annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Tuesday June 8th.

Jay Thomas, Grund Technical Solutions, LLC., “Probe Cards with Modular Integrated Switching Matrices”:

For the last 30 years, most scribeline parametric testing has been approximately 85% Current-Voltage (I-V) testing and 15% Capacitance-Voltage (C-V) testing. For these types of tests a 10 MHz bandwidth switch matrix has been sufficient.

However, some of the larger fabs such as HP, IBM, and Intel have started performing pulsed Current-Voltage (PIV) and electrostatic discharge (ESD) testing. These customers started this type of testing about four years ago unknown to Agilent & Keithley (the two largest DC parametric tester suppliers). This PIV and ESD testing requires high frequency switch matrices with 1 GHz bandwidth. [For more about ESD testing please see Jay’s second presentation below in this session.]
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IEEE Semiconductor Wafer Test Workshop – Signal Integrity – Session Five (Tuesday)

Here are the highlights from Session Five – Signal Integrity of the 20th annual IEEE Semiconductor Wafer Test Workshop (SWTW) from Tuesday June 8th.

Gert Hohenwarter, GateWave Northern, Inc., “Hidden Performance Limiters in the Signal Path”:

For high frequency signals, designers typically pay attention to avoiding coupling to adjacent signal lines to prevent cross talk. However, they need to look at many other areas of the design including coupling to power or sense lines, signal impedance mismatch, resonances, and the power distribution/delivery system (PDS). Coupling and mismatch may lead to resonances which reduce the operating speed or reduce the switching margin. These areas may also increase crosstalk increasing noise levels and also reducing switching margin. In addition, problems in the PDS may also reduce operating speed or switching margin.
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IEEE Semiconductor Wafer Test Workshop – Standards and Methods – Session Four (Monday)

Here are the highlights from Session Four – Standards and Methods of the 20th annual IEEE Semiconductor Wafer Test Workshop (SWTW).

Mark McLaren, Integrated Technology Corporation, “Metrology Solutions for Very Large Probe Cards”:

Over the past few years as the number of memory devices to be tested in parallel has increased so has the size of probe cards to support this multisite testing. A few years ago memory probe cards grew to 440 mm diameter and recently they increased to 480 mm diameter. Now a similar growth in size has been seen for non-memory applications. Even though the parallelism (number of devices to be tested at once) has increased (but not on the scale of memory parallelism), the size increases have been the result of pushing more testing from package test to wafer test. These additional tests have required more local test resources (circuitry close to the device being tested) which require more real estate on probe cards.
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IEEE Semiconductor Wafer Test Workshop – Improving Cost of Ownership – Session Three (Monday)

Here are the highlights from Session Three – Improving Cost of Ownership of the 20th annual IEEE Semiconductor Wafer Test Workshop (SWTW)

Rey Rincon, Freescale & Jeff Greenberg, Rudolph Technologies, “Optimizing Test Cell Performance Using Probing Process Analysis and Predictive Scrub”:

Rey summarized efforts at Freescale to improve test cell performance with multi-tier cantilever probe cards by investigating prober performance, probe card performance and probe card analyzer correlation to the test cell.
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IEEE Semiconductor Wafer Test Workshop – High Temperature Probing – Session Two (Monday)

Here are the highlights from Session Two – High Temperature Probing of the 20th annual IEEE Semiconductor Wafer Test Workshop (SWTW)

Keith Breinlinger, FormFactor, “Addressing the Operating Challenges of Full Wafer Contactors”:

Keith started by providing a real good analogy of the challenge of wafer probing in terms of contacting the edge of each sheet of papers in a sixteen high foot stack. He used the new full wafer probe cards SmartMatrix (DRAM) and the TouchMatrix (NAND FLASH) as the basis of his presentation.
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IEEE Semiconductor Wafer Test Workshop – New Contact Technologies – Session One (Monday)

Here are the highlights from Session One – New Contact Technologies of the 20th annual IEEE Semiconductor Wafer Test Workshop (SWTW)

Jay Kim, Western Specialty Technologies, LLC, “New Probe Card Architecture – Ceramic without MLC”:

He showed how Fine Instrument Co., Ltd. (Korea) built a new probe card architecture which eliminates using multi-layer ceramics (MLCs) to avoid the cost and lead times issues.
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IEEE Semiconductor Wafer Test Workshop – Opening Session (Sunday)

The 20th annual IEEE Semiconductor Wafer Test Workshop (SWTW) started this evening. Rumor has it that attendance is over 240 this year which is a vast improvement over last year’s 160 or so attendees. At the peak the conference had almost hit 600. Things started off well with a reception where I had the chance to catch up with many industry friends and colleagues.

After dinner, Jerry Broz the General Chair kicked things off with the “Probe Year in Review”. In summary:
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Pass or Fail? The Limits of Integrated Circuit Testing

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.

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