Bypassing 2.5D

Did Nvidia’s announcement that it would use 3D packaging with silicon-through-vias on some forthcoming Pascal graphics processors to make more memory available with minimal delays signal the start of a general acceptance of stacked memory chips?

IPC Apex Expo was the best in many years. Attendance was good, both in the conference as well as on the show floor. Even Thursday morning saw potential buyers visiting exhibitors in their booths. Capital equipment buyers were twice as optimistic as in the prior year — about 65% stated that they planned to buy equipment this year versus about 30% last year. Exhibitors stated that they were making sales and getting commitments for future trials in their booths during the show — event though there was little in the way of new systems to be seen in the hall. One independent equipment sales rep stated that he had more customer meetings at this show than at the five previous events combined.

New product introductions and improvements abounded. EarthOne Circuit Technologies Corporation (dba eSurface Technologies) created quite a stir with its sponsorship of the Tuesday luncheon to announce its new additive printed circuit board process.

Six OEMs responded to the IPC’s effort to get them more engaged at the management level. The Ambassador Council held its first meeting to explore how it could provide help to further the knowledge and success of IPC members. The executive management meetings’ programs were excellent but still failed to bring in more than a handful of bare board fabricators. Counterfeit components was one of the hot topics throughout the event.

On the other hand, a number of historic names (Christopher Associates, Multiline) were missing from the show — victims of the business conditions and America’s continual decline in the bare board market as well as direct incursions by foreign capital equipment producers. Some exhibitors were still introducing their “new” systems and processes after three or more years of failing to gain traction. However, it warmed my heart to see the resurrected Dynachem name and logo back in America in Osvaldo Novello’s booth, Automatic Lamination Technologies S.R.L.

The IPC event has appeared to have morphed into an analog of the old Nepcon West in terms of massive entertainment activities. The major corporate exhibitors not only took large booths but also used to arrange major hospitality events, receptions, and cruises which captured many of the show attendees. They spent hundreds of thousands of dollars at Nepcon. This put the smaller exhibitors at a distinct disadvantage.

When the IPC established its first trade show it decided to level the playing field a bit for the smaller exhibiting members. It banned major hospitality events during the show that would take attendees away from the event. Some companies that violated this rule were even penalized by having their chance to select the following year’s booth moved to the last position. The IPC arranged for cruises (in San Diego). It produced major galas with music, food, entertainment, and other activities. It solicited sponsors — who received credit for their participation. The price for admission to the event was reasonable. Many companies bought tickets for their customers. It was a great night for all.

But, things have reverted. Companies with deep pockets have already started to reserve ballrooms, night clubs, and to plan other major events for IPC Apex Expo 2015. I do not think that this is a good trend.

Bob Black of Juki Automation said that sales closed during the first two days of the show actually “more than paid” for the show. He said that although January was a bit slow, February sales were strong and he expected March to also be a good month.

Chris Fussner of Yamaha (TransTech) stated that he expected a good year in 2014 as his American distributor organization achieved a positive cash flow in second year (2013).

Don Walsh stated that Ueymura had a record year and a strong start in 2014.

Nihon Superior’s Tetsuro Nishimura said that his booth was busy throughout the show and that he was glad that he came. He’ll be back next year to exhibit with the IPC for the 15th time.

OMG’s Mike Carano (admitted to the IPC’s Raymond E. Pritchard Hall of Fame, the IPC’s highest honor, during the awards luncheon) stated that his company has now captured a 30% share of the North American market for its products.

Dr. Bill Elder introduced Maskless Lithography’s (MLI’s) direct imaging system for liquid photoimageable solder masks (LPISM).

Crunch time

Early reports from the CPCA show state that it is a “disaster.” One of the major exhibitors said that no one came to their booth on Day 1, and only a dozen or so – but no buyers – on the second day. Another stated that Day 1 was awful and that Day 2 was a bit better, it was just terrible in terms of attendance. Semicon China held in Shanghai at the same time was reported to also have experienced the same malaise — a dearth of customers, prospects or visitors of any type.

Can the international uncertainty be the cause? Can the economic woes and diplomatic strife in the world be the reason? Could the international cultural differences and distrust as shown through the investigations of the disappearance of Malaysian Airlines flight 370 be at fault? Are the rapid changes in the electronics industry coupled with continued closures and consolidations be the reason? Could it be that potential buyers are tired of sending armies of their troops to exhibits to see much of “the same old stuff?”

Do these events need to change for today’s and tomorrow’s technology, markets and products? Is the gravitation of business to fewer larger enterprises at fault? If so, how? We believe that ALL of these — and more — are at fault. At the same time, we note that technical conferences, which do not need to draw volumes of visitors to consider them successful, generally continue to attract members of their particular buying public.


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Sample Size is Important in Weibull Analysis Too

Some time ago I posted on “The Curse of the Early First Fail” and “Interpreting Weibull Plots.” Both of these posts related to using Weibull analysis to make sound engineering decisions.

Recently, a reader asked if sample size is important in Weibull analysis. It is interesting that few who do Weibull analyses discuss the effect of sample size. So, let’s do it now. Consider Figure 1. This figure shows Weibull analysis used to compare cycles to fail for Alloy 1 and Alloy 2. Considering that the slope of each curve is about the same, most people would say that since the scale for Alloy 2 is greater (1320 versus 1172), Alloy 2 is superior. But, is the difference statistically significant? By using a simple Two Sample t Test, we can analyze the data and find that there is only a 62% confidence that Alloy 2 is better than Allot 1. Flipping a coin gives us 50% confidence, so this result is not encouraging. Four samples is seldom enough to make a confident engineering decision.

Figure 1. A Weibull plot of Alloy 1 and 2 with only four samples.

If we perform the experiment again with 20 samples, we get the Weibull analysis as shown in Figure 2. Note that although the scale parameters have not changed too much, the shape parameters have changed significantly. The original 4 sample test is just not enough to really lock in on the real shape numbers for the samples. By also performing a two sample t test on the 20 sample data, we now find we have a 99.6% confidence that Alloy 2 is superior to Alloy 1. So, with 20 samples we can confidently say that Alloy 2 is superior to Alloy 1.


Figure 2. A Weibull plot of alloys 1 and 2 with 20 samples.

What is the minimum sample size for your test to be confident in the result? It can vary quite a bit and only by analyzing the data with a t test, after the experiment, can you know for sure. But my experience would suggest that you should never have less than 10 samples, and preferably 15 or more.


Dr. Ron


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A ‘Worthington’ Idea

EMS firm Worthington Assembly last week announced a deal to market its EMS services via CircuitHub.

WAI is a small EMS company located in Western Massachusetts. Like many in the sub-$20 million space, WAI’s owners double as its salesmen, and the firm relies heavily on word of mouth (and engineers changing jobs) for prospecting.

CircuitHub developed a universal parts library and is offering that, along with BoM, bare board and assembly quoting. PCD&F did a piece on the company last year.

Chris Denney, WAI’s CTO (and a sometime CIRCUITS ASSEMBLY columnist) explains the partnership here.

Clearly, more opportunities to order boards from a variety of suppliers via a single website are popping up, with the site typically offering free software in order to gain visitors (FabStream, for example, offers use of a PCB CAD tool capable of up to 12 layer boards, and SnapEDA offers simulation).

I would not anticipate larger EMS firms would go this route. But for smaller ones, whose cost of sales would be proportionally high relative to its income if it employed direct outside sales, using app-based vendors could be a creative and low-cost way to find new customers.

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RoHS July 2014 Deadline: Medical Devices and Control Instruments

In 2011, the European Union issued a new directive that updates and supersedes RoHS; it has come to be known as the RoHS Recast or RoHS 2. Under the updated directive, as of July 22, 2014, RoHS restrictions will apply to Category 8, medical devices, and Category 9, monitoring and control instruments. Before we look at what those categories include specifically, here’s an overview of deadlines yet to come under the RoHS Directive.

So, what’s in Category 9, Monitoring and Control Instruments? The types of equipment that are in category 9 of the RoHS directive have a main function of monitoring or control, says Dr. Paul Goodman in Electronics Weekly, quoted here because it stands out as one of the better summaries of what to expect from Category 9. Monitoring, Goodman says, would include measurement – ergo thermometers, analytical spectrometers and digital voltmeters are all in category 9 because they monitor temperature, concentration, voltage, etc.

Monitoring and control functions are features of thermostats that monitor and control temperature and industrial process controllers that monitor and control a variety of process parameters. Other category 9 products include smoke detectors, fire alarms, traffic signals (control of traffic), X-ray imaging of luggage or electrical equipment (but not medical X-ray which is category 8), spectrum analyzers, etc. It is incorrect however, to assume that all laboratory equipment is in category 9 as these products must monitor or control as their main function. – Dr. Paul Goodman, EW

So, what’s in Category 8, Medical Devices? Medical devices were exempt in the original directive, which meant they could contain unlimited amounts of toxic metals and plastics and still be marketed as RoHS compliant. Not anymore. Medical devices are still a broad category, and note that RoHS is not targeting “in vitro diagnostic medical devices” yet in 2014.

So what is targeted? For example:  radiotherapy equipment, cardiology, dialysis, pulmonary ventilators, nuclear medicine, laboratory equipment; other appliances for detecting, preventing, monitoring, treating or alleviating illness, injury or disability; but specifically excludes all implanted and infected products.

How are companies handling RoHS compliance? Industry’s leading companies are managing their compliance at various stages. There are challenges.

Certainly one challenge with RoHS is the many different formats suppliers use to submit their information. We asked a group of manufacturing risk assessment professionals on LinkedIn, “What form of documentation do you typically get from suppliers?” Here are the myriad answers.

Note: a good software should eliminate that challenge, for instance, by loading all information into a uniform data repository, so the resulting standardized data parameters are searchable, rational and reportable.


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Quiet Flight

The mystery over the whereabouts of Malaysian Airlines Flight MH370 is a very serious and tragic matter. That the 777 was equipped with sophisticated tracking devices and could still disappear confounds me.

Let’s assume the pilots turned off the transponder. This is a serious question: Why are the transponders manually operable? Is there any value to a commercial pilot or navigator being able to “go silent?”

Perhaps there is, but I don’t see it.


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An Example of Cpk and Non Normal Data In Electronics Assembly Soldering


Let’s see how Patty is doing after teaching her first class at Ivy U…

Patty arrived at home after teaching her first class at Ivy U and she couldn’t contain her excitement. For the next couple of hours her husband, Rob, had to politely listen to her talk about how amazing it was to teach the young, bright, enthusiastic, future engineers.

Time went quickly and, before she knew it, she was standing in front of the class for her second lecture.

Patty reviewed quickly the fact that it was incorrect to average Cpks and that, to calculate a Cpk, the data should be normally distributed.

“The question was asked last time, how one can tell if the data are normal? Minitab can be used to plot the data on a normal probability plot. By eye, we can get a good sense if the data are normal or not. In addition, Minitab will perform various tests, one of them being the Anderson-Darling Normality Test,” Patty began.

“Let me show you some real data to demonstrate this,” Patty continued.

“When assembling a smartphone like the new Druids, the mechanical tolerances for the many tiny capacitors and resistors are very precise. One common capacitor size is only 0.6mm long.” Patty paused as she saw a student’s hand raised.

“Yes, Martin?” Patty asked.

“Professor, you mean 0.6cm, right?” Martin asked.

“No, 0.6mm,” Patty answered.

Patty’s answer caused quite a bit of murmuring, finally Patty had to ask for order.

“Why is everyone surprised?” Patty asked.

“Professor, that is much smaller than a grain of rice, it is more like the size of a grain of sand,” Alison March responded.

“This is fun,” Patty thought, “and good timing.”

Patty showed a slide of passives on a match head and passed around a teardown of Druid smartphone with a magnifying glass so that the students could see how small the passives were.

It took a while for the class to calm down.

Patty then said, “And about 200 to 500 capacitors and resistors of this size are individually placed and soldered in the electronics assembly process in each smartphone.”

The student’s mouths were agape.

“OK, let’s discuss how these little rascals relate to SPC. My company orders billions of these electrical components each year. We are sent a sample lot to approve a larger order. For the components of interest, we already know that the mean length is 0.6mm, the 3 sigma (standard deviation) tolerance is +/-0.03mm. So, the lower spec limit is 0.57mm and the upper spec limit is 0.63mm. This equates to a Cpk = 1.00,” Patty went on.

Patty put a PowerPoint slide up that showed the data.

“The data for the sample lot is on the left. What is the problem?” Patty asked.

Charles Parsons raised his hand.

“Yes, Charles?” Patty asked.

“Well, Dr. Coleman, the standard deviation for the data is 0.15 and the resulting Cpk is only 0.67, so the targets are not met” Charles answered.

“Precisely,” Patty replied.

“We then went back to the supplier and asked them to fix the problem. The graph on the right is from the capacitors they sent us 3 weeks later, after they claimed to have solved their manufacturing process problems,” Patty explained.

“What do you think?” Patty asked.

There was a lot of murmuring. Finally DeShaun Martin raised his hand.

“Yes, DeShaun?” Patty acknowledged him.

“Well, Professor, it looks like they simply sorted out the parts to make the sigma lower and Cpk higher,” DeShaun responded.

“Precisely,” Patty said.

“I don’t see what is wrong with sorting,” Sandy Lisle commented.

“You see from the Druid smartphone that I passed around that it is so densely packaged with components that there is hardly any room in it. To achieve this density we have to perform tolerance analyses to assure everything will fit. In all of these analyses we model with normal distributions. With a sorted distribution we will likely have more tolerance interferences,” Patty answered.

“Look at the red arrow. There will be an excess of components with this size and a lack of components of the size where the green arrow is pointing. These differences will cause some tolerance interferences with the pads on the printed wiring board where the passive will be assembled,” Patty continued.

“Can you review? How we can tell that the distribution on the right is not normal?” Conor Stark asked.

“Sorry, I almost forgot. Look at the normal probability plot for the sorted data. Note how it diverges from the straight line on the ends. Also the Anderson-Darling value for p is <0.05. These two criteria are cause to reject the hypothesis that the data are normal,” Patty finished.

Patty was just wrapping the class up when someone raised their hand.

“Yes, Natalie?” Patty asked.

“What was the final outcome?” Natalie asked.

Patty chuckled, obviously she should share he result of this adventure.

“Oh, yes. We could not use the parts for the Druid smartphones, but they were OK for some toys we were assembling. In addition we insisted on a 30% discount, since the passives did not meet the specification,” Patty answered.

As she was cleaning up, two of the female students came up to Patty. One them, Justine Randall spoke for the two.

“Professor Coleman, you are an inspiration for us. We hope in 20 years we can be just like you,” Justine said with emotion.

Patty was indeed touched, but as she left the classroom, she decided that she had to start dyeing her hair.


Dr. Ron


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0.4mm Pitch BGA is Awesome

I recently had a conversation with a friend about 0.4mm pitch BGAs. The specific part is the FreescaleFreescaleKL03KL03 ARM Coretex-M0+ microcontroller in a 1.6mm x 2mm, pitch package. That’s a 20-ball wafer scale BGA form factor.

I don’t have an actual part to photograph next to a grain of sand, but trust me (or don’t), it’s really small.

Ti 0.44 pitch dimensionsThe challenge, and the reason I suggested a QFN form factor instead, is the costs involved. If you have the extra budget money for more expensive PCBs, then go ahead and use this form factor. You probably won’t be able to use this package in cost-constrained situations.

The simple reason is that you can’t escape route the inner six pins without using super small vias between pads, or in pads and filled and plated over. The page on the left is from a Ti doc, but any variations in geometry will be minor.

You can see that you can’t put a trace between the pads. Maybe a 2 mil trace, but maybe not. There just isn’t much room. The recommended method is to put microvias in the pads and have them filled and plated over at the board fab house. Never put a via in a micro BGA pad unless it’s filled, plated over, and flat.

Duane Benson
There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.
But open vias in pads aren’t one of them

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Defining the New World

Where are 2 1/2D and 3D going? How will “active” interposers be defined — and where will they be used? What’s the real scoop for TSVs (through-silicon vias)? The Pan Pacific Microelectronics Symposium held this month seemed to confuse some attendees and point out the apparent need to sort out the terminology used in various packaging schemes. One must wonder how the discovery of “artificial graphene” reported by a European university will affect the development of applications for the real thing?

Value and change — topics for consideration and discussion. How do you determine value? How much is a semiautomatic printer for LPISMs worth if it can produce better than 2.0 mil (50um) dams in 1.0 mil (25um) thick solder mask? How much is a system that exposes a “standard” mask in less than 7 sec. worth? At what point does one replace a fully depreciated piece of equipment or a line with a more advanced capable system? What is the ideal or minimum practical “payback” time in your facility? How much does it truly cost you to evaluate a “free” sample of a material or specialty chemical? Can you determine the value of a new system/product simply by yield improvement? Or by throughput? Or reduction in energy usage? Or waste disposal costs? What would it take for you to install a new “not-in-kind system” replace an old “standard”? How do you respond to an offer of a “new” technology? What claims or benefits would motivate you to take action to evaluate it? Let us know!

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M&A is Here to Stay

There’s been a flurry of EMS acquisition activity of late, with Natel’s acquisition of EPIC Technologies and Benchmark’s pickup of Suntron and CTS among the larger deals. Lincoln International, an M&A advisor, counts nine transactions in the fourth quarter alone, out of 24 total for the year. While Lincoln’s numbers shouldn’t be considered absolute – my guess is that worldwide they are off by well over 50% – they do provide a reasonable snapshot of the industry at a given time.

While I dare say Nam Tai will be the largest EMS company to close its doors in 2014, when all is said and done, I predict we will see a record number of shops close or be bought out in asset deals.

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When is an 0201 Not an 0201?

I’m working on a special project here that involves some 0402 LEDs and 0201 resistors. When doing such a thing, you should always check the footprint you’re using against the datasheet. When using extra small parts, like this, I recommend making a custom footprint unless the one you picked is exact, and I mean exact. There just isn’t an margin for error at these geometries.

Take a look at the table on the right. The dimensions are in mm. Spot anything a bit off? Counter to most datasheets, the sizes listed in the “Type” column are metric sizes. At DigiKey, the package was listed as “0201 (0603 Metric).” I see that all the time, but for some reason, most datasheets show the package name in US size while listing the dimensions in metric.

The first table was at the front of this data sheet (page 5). The second table was on page 35 – the opposite end of the datasheet.

We do occasionally get boards with metric size pads for a US-size part, or vice versa. Sometimes we can make it fit, but not always. Bottom line, is to check and double-check. I caught this one because the dimension 0.54 mm is about 21 mils, too small for an 0402. That, and the fact that the table doesn’t list an 0201 size.

Duane Benson
Is it Bigfoot or Sasquatch?

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