The indium additive relieves stresses that drive whisker growth. 

Copper components in electronic packages (e.g., lead-frames, interconnects, integrated circuit leads and press-fit connector pins, to name a few) are often electroplated with tin (Sn) to prevent tarnishing and to facilitate subsequent soldering. With passage of time during storage or service, long whiskers grow from these tin coatings, causing electrical shorts between neighboring circuitry, posing serious reliability risks.^1-3 This problem is particularly problematic in long-life applications, and failures have been reported in many arenas, including aerospace, nuclear power plants, automotive electronics, and military electronics systems, causing damages worth millions of dollars.

Figure 1. Surface of a copper substrate with a 3µm-thick electroplated coating, after ambient temperature aging for 1.5 months. The Sn version shows multiple whiskers.

A number of approaches to mitigate whisker growth have been pursued during the past 30 years, including additions of Pb, Bi, Au, Sb or Ge, or post-plating thermal treatments.4-8 These approaches mitigate whisker growth to varying degrees; however, none eliminates it. Over time, and under thermal-mechanical excursions, whiskers continue to grow.

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From secure data exchange to managing EoL parts, the applications are numerous. 

In last month’s discussion of how electronics companies first began to use Blockchain technology to automate and simplify “high-friction” multiparty processes, we noted many of the earliest projects tended to focus on the relationship between a single “sponsor” company and its partners. In other cases, companies worked together as a consortium to solve a common problem. Quickly, however, electronics companies began to leverage applications originally developed for other industries, especially to leverage the “track and trace” capability originally developed for the food industry.

Basing a new blockchain network on functionality that has been developed and implemented for another network¹, even in a completely different industry, lowers the cost of entry and simplifies the process of setting up that new network. That has turned out to be very important, since it also makes it easier to create a valid business case for the application.

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Updates in silicon and electronics technology.

Ed.: This is a special feature courtesy of Binghamton University.

Integrated photonic circuits demonstrate ultralow loss. EPFL researchers have developed a technology that produces silicon nitride integrated photonic circuits with low optical losses and small footprints. Silicon nitride has been a material of choice for applications where low loss is critical, such as narrow-linewidth lasers, photonic delay lines, and those in nonlinear photonics. The team combined nanofabrication and material science based on the photonic Damascene process developed at EPFL. With this process, the team made integrated circuits of optical losses of 1dB/m, a record value for any nonlinear integrated photonic material. That low loss considerably reduces the power budget for building chip-scale optical frequency combs used in applications that include coherent optical transceivers, low-noise microwave synthesizers, lidar, neuromorphic computing and optical atomic clocks. (IEEC file #12282, Photonics Media, 5/6/21)

Samsung develops advanced chip packaging tech. Samsung Electronics has developed an advanced chip packaging technology for high-performance applications. Its next-generation 2.5D packaging technology, Interposer-Cube4 (I-Cube4), is expected to be widely used in areas like high-performance computing, artificial intelligence, 5G, cloud and data centers with enhanced communication and power efficiency between logic and memory chips. I-Cube is heterogeneous integration technology that horizontally places one or more logic dies, such as CPU and GPU, and several high bandwidth memory dies on a paper-thin silicon interposer. (IEEC file #12285, Science Daily, 5/6/21)

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The largest circuit board fabricators are pulling away from the rest of the market. 

This is the 25th NTI-100 report. The author cannot believe he has done NTI-100 such a long time. As years go by, it becomes more difficult to accurately record revenue data of privately owned PCB fabricators, and there are many. As a result, the data of about one-fifth of the top PCB companies are questionable. Nevertheless, it is interesting to see the revenue trend.

As usual, data compiled by trade organizations and with the assistance of many of the author’s friends around the globe were vital to completing this report. He expresses his gratitude to all who helped. Any errors are strictly his responsibility.

The 2020 average exchange rate conversion of revenue from local currencies to the US dollar was made using the exchange rates listed in TABLE 1. Since various organizations and individuals seem to use slightly different rates, the results may differ but only slightly.

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