Happy’s Tech Talk

May 07, 2025

Happy’s Tech Talk #38: Novel Metallization for UHDI

I have been involved in high-density electronics substrates since 1970 when I joined Hewlett-Packard’s RF semiconductor group after college. Figure 1 shows the difference between trace/space lithography for substrates and silicon starting in 1970. My projects involved sapphire circuits for RF devices, but the figure displays the state of PCBs and integrated CMOS circuits and their packaging, not discreet RF devices. Even then, semiconductors were 50X higher density.

---

February 03, 2025

Happy’s Tech Talk #37: New Ultra HDI Materials

Some new materials have been introduced in the past year for ultra high density interconnect (UHDI), a convenient title for developing high density technologies. They have received labels like semiconductor-like PCBs (SLPs), redistribution layers (RDL), flip-chip ball grid array (FCBGA), and interposers. The early 2000s saw the creation of these organic substrates for flip-chip IC packaging. The initial construction was composed of a BT core with build-up layers of the Ajinomoto Build-up Film (ABF)

---

January 14, 2025

Happy’s Tech Talk #36: The LEGO Principle of Optical Assembly

Dr. Steven Case of Avanti Optics Corporation once advocated a new approach to photonic assembly, based on the LEGO principle. He compared today’s erbium-doped fiber amplifier (EDFA) technology to the crude point-to-point wiring of early model circuit boards, which gave way to modern circuit boards that could be considered prefabricated interconnects.

---

December 12, 2024

Happy’s Tech Talk #35: Yields March to Design Rules

Ultra high density interconnect (UHDI) has many forms, structures, and alternatives, so capturing all the variations and reducing them to design rules has required some departures from traditional IPC design standards. In this column, I’ll be discussing the IPC UHDI design guidelines and standards. The fundamental question is: “Do you need HDI or microvias?”

---

November 12, 2024

Happy’s Tech Talk #34: Producibility and Other Pseudo-metrics

As an engineer, I thrive on data, and one of my favorite forms is metrics. However, the one metric that has always challenged me is producibility. I define this as more than just passing a DRC in CAM, but the entire envelope of “simplicity of design,” “suitability for test,” and many more. Yet, producibility seemed to be different for different engineers and we had no clear way to establish and define producibility other than opinion. When I worked at HP, the company invested in a methodology called design for manufacturing and assembly using the GE/Hitachi Methodology and Dewhurst-Boothroyd software. Finally, I had a methodology that created a producibility score.

---

October 14, 2024

Happy’s Tech Talk #33: Wet Process Management and Control

My August column introduced sensors that are useful in measuring critical components of the various wet processes in printed circuit fabrication. Now, I will close the loop and discuss building automatic controllers. Table 1 shows the three phases of process control. Hopefully, you have conducted some type of wet process audit using the worksheet in my last column and now have some idea of where improved process control will improve performance.

---

September 03, 2024

Happy’s Tech Talk #32: Three Simple Ways to Manage and Control Wet Processes

My three favorite sensors for wet process control are process concentrations with specific gravity, plating replenishment based on ampere-hours, and active concentrations with color indicators. To start enrolling in wet process control, I advise doing a process audit (Table 1) with a real time analyzer, which is a conductivity probe and a thermometer. You can also add a hydrometer, a multimeter, and a color analyzer.

---

August 12, 2024

Happy’s Tech Talk #31: Novel Ultra HDI Architectures

Ultra HDI has become the focus for many fabricators, especially as the follow-on for the 40-year-old conventional HDI. But there is more to UHDI than just finer traces and spaces. Novel architectures have been developed that complement the new dense lithography. One of the major advantages of HDI, and especially ultra HDI, is the miniature features of the process. Since the microvias and lands are so small, they can be swung around at various angles between the BGA lands. The angles and distances will depend on the BGA pitch and where the microvia is placed relative to the BGA SMT land.

---

July 01, 2024

Happy’s Tech Talk #30: The Analog Computer

Although computer technology has taken enormous leaps, including HPC machines that now exceed the exascale limits, the analog computer is making its comeback. I had the fortune to learn about and program analog computers and programs in early 1966. The various analog computers came into their own during World War II to calculate artillery trajectories and for bombsights (Figure 1a, the Norden Bombsight). Their use continued to grow, and every major aeronautical design and manufacturer, as well as university, had them in the 1950s and 1960s.

---

June 05, 2024

Happy’s Tech Talk #29: Bend-to-Install Semi-flex FR-4

A special case of rigid board applications is when you would like to bend the board but don’t need it to flex. We have called this case “bend-to-install” or sometimes “semi-flex.” Many electronics applications are in this class of assembly, as illustrated: Rigid board needing height adjustments, automotive lighting, industrial cameras, engine control units, and and-held portable units.

---

May 07, 2024

Happy’s Tech Talk #28: The Power Mesh Architecture for PCBs

A significant decrease in HDI substrate production cost can be achieved by reducing the number of substrate layers from conventional through-hole multilayers and microvia multilayers of eight, 10, 12 (and more), down to four. Besides reducing direct processing steps, yield will increase as defect producing operations are eliminated.

---

April 08, 2024

Happy’s Tech Talk #27: Integrated Mesh Power System (IMPS) for PCBs

A significant decrease in HDI substrate production cost can be achieved by reducing the number of substrate layers from conventional through-hole multilayers and microvia multilayers of eight, 10, 12, and more to only two layers. Besides reducing direct processing steps, the yield will increase as defect-producing operations are eliminated. The integrated mesh power system (IMPS) was invented in the latter years of MCM-D use for thin-film fabrication. Those geometries fit today into our use of ultra HDI.

---

March 14, 2024

Happy’s Tech Talk #26: Balancing the Density Equation

Printed circuit design and layout is a creative process that has profound implications for electronic products. With the need for more parts on an assembly, or the trend to make things smaller to be portable or for faster speeds, the design process is a challenging one. The process is one of “balancing the density equation” (Figure 1) with considerations for certain boundary conditions like electrical and thermal performance. Unfortunately, many designers do not realize that there is a mathematical process to the layout of a printed circuit

---

February 21, 2024

Happy’s Tech Talk #25: Lab-on-PCBs for Medical Diagnosis

COVID-19 created a rush for simple and quick medical diagnostic tests for the public. Biomedical MEMS (bioMEMS) have emerged as a subset of MEMS devices for applications in biomedical research and medical microdevices, with an emphasis on mechanical parts and microfabrication technologies. Applications include disease detection, chemical monitoring, and drug delivery. There has been rapid market growth for bioMEMS technologies, and many bioMEMS devices are already commercially available. There is great potential for large-scale commercialization of microfluidic-based LoC and LoPCB technologies.

---

December 06, 2023

Happy’s Tech Talk #24: Performance and Registration—Coupons to the Rescue

Registration is one of the most important features for any PCB fabricator, but the capability for multilayers is a lot of work on the fabricator’s part. CAM settings, multilayer lamination, X-ray analysis, AOI measurements, imaging capability, and drill accuracy all play an important part in this capability. Software and panel parametric coupons are important because they aid in registration performance.

---

November 07, 2023

Happy’s Tech Talk #23: Large Panel Processing

Panel size is an important aspect of PCB productivity, yields, and cost. If a fabricator or assembler can process larger panels then their productivity increases and their cost per board drops—provided that yields are not affected. Yields are an important process parameter, as they affect all costs and performance measures; they are driven by defect density, and that affects considerations of larger panel sizing. Defect density is not often talked about in PCB fabrication, unlike wafer processing, where it is a driving factor.

---

October 18, 2023

Happy’s Tech Talk #22: Computer-aided Bare Board Testing, Revisited

This is from a paper I gave at an IPC conference in Denver, Colorado, in 1983. Obviously, computers have come a long way since 1983, so the minicomputer I talk about using here can easily be replaced by a simple desktop or notebook computer. The statistics are from Dr. W. Edwards Demings’ first book and the software used is from NIST’S Engineering Statistics Handbook. It’s still very appropriate.

---

August 10, 2023

Happy's Tech Talk #21: Embedded (Flush) Circuits

In his Tech Talk series, Karl Dietz wrote several times about embedded circuits1, particularly detailing flush circuit technology and recessed circuit processes. In his column, Karl outlined two processes that have been used to produce these “flush” circuits: Imprint technology, based on the work of George Gregoire at Dimensional Imprint Technology, Inc., and circuit transfer process, based on Samsung Electro-Mechanics.

---

July 10, 2023

Happy’s Tech Talk #20: Teaching Coding to Kids—The UK’s Micro:bit Tool

I recently learned about the micro:bit programming tool, and an important initiative in the UK to teach coding to young students. It made such an impression on me that I purchased the training set, went through the tutorial and plan to send it to my 10-year-old grandson. He told me he’s already eager to start. First, I showed it to my son and asked him to start learning to use it so he can help his son if he has any questions. It’s about $18 to get the complete system, so it’s not too expensive and I hope to see it spread more widely in the United States.

---

May 30, 2023

Happy’s Tech Talk #19: Next-generation Electroplating Systems

Electroplating has always been at the core of printed circuit fabrication. It was the first process I was assigned to as a new young engineer at Hewlett-Packard in 1970. Of course, the copper-plating process was copper pyrophosphate, an alkaline—a very temperamental bath from MT Chemicals Inc. Soon after I mastered the chemistry and control of this plating solution, I had the opportunity to test and introduce PC-GLEEM from LeaRonal, Inc., a new sulfuric acid-based copper sulfate copper-plating chemistry. We never switched back.

---

May 15, 2023

Happy’s Tech Talk #18: Putt’s Law and the Successful Technocrat

I have read very few humorous technical columns in my career, but the one exception is an 11-part series, “The Successful Technocrat” by Archibald Putt, which was featured in Research & Development Journal in 1976 and 1977. The author later published a book, Putt’s Law and the Successful Technocrat2, and years later, I tried to buy it—only to have to wait eight years to get it. In the meantime, I have saved copies of the articles and sent them to friends.

---

March 10, 2023

Happy’s Tech Talk #17: Can You Build EVs Like PCs?

You probably haven’t heard of Foxtron, but if you follow electric vehicles (EVs), you will soon. Foxtron is Foxconn’s EV startup, created in partnership with Yulon Group (YLM), a Taiwanese car manufacturer of NISSAN designs. In 2021, the company introduced three EV models in Taiwan and in 2022, Foxtron introduced a new all-terrain utility pickup Model V and a lower-cost Model B sedan.

---

January 26, 2023

Happy’s Tech Talk #16: Protocols for a Smart Factory Future

Karl Dietz never wrote on automation and the Smart factory, but these topics have been a priority for larger OEMs since the early '80s. I became involved in automation planning after designing and building Hewlett-Packard’s newest printed circuit fabrication facility in Sunnyvale, California. The journey to a Smart factory is evolutionary; it starts with a thorough business plan that charts a roadmap for your enterprise into the future.

---

January 05, 2023

Happy’s Tech Talk #15: Printed Electronics Using Flex

The printed electronics sector is presently an area of great interest to many in the electronics manufacturing industry. Because of their incredible utility, printed electronics are poised to generate tens of billions of dollars in the coming years. According to IDTechEx, the total market for anticipated and potential printed electronics was near $62 billion in 2019 and expected to grow to nearly $81.8 billion within ten years. Earlier projections of a $300 billion market were floated a few years ago, but the $62 billion figure is still considerable and roughly equal to the current value of the global printed circuit market.

---

December 08, 2022

Happy’s Tech Talk #14: Palladium as a Final Finish

Karl Dietz never wrote on the topic of palladium as a final finish, but he did write about gold plating as a final finish and had an excellent discussion on copper plating. But palladium now has a renaissance as a final finish. It was very popular in the 1970s, as the only other final finishes were tin-lead reflow-Ni/Au-OSP or immersion tin. Palladium was very popular with the automotive industry then and a major supplier of boards was Photocircuits of Glenn Cove, New York.

---

October 27, 2022

Happy’s Tech Talk #13: Direct Imaging Revisited

It is hard to believe we have had direct imaging for 40 years, starting with Excellon’s introduction of its DIS-2000 argon laser imager. Since then, companies in 11 countries, ranging from Israel to Norway1, have developed various digital direct imagers. Karl Dietz wrote about this technology several times in his columns2, noting early on the skepticism that laser direct imaging would hit a Golden Age. So, where are we at now?

---

October 10, 2022

Happy’s Tech Talk #12: Nano-Cu Paste for Microvias

Complex build-up HDI technologies continue to expand in applications. Copper electroplating of vias has been perfected but the process is yet another electroplating solution to maintain and can sometimes be a lengthy process. Current conductive paste fills are not as conductive as solid copper but provide reduced cycle time, are still highly conductive and are cost effective.

---

August 30, 2022

Happy's Tech Talk #11: An Update on Inkjet Technologies

Since the first inkjet printer appeared from Hewlett-Packard in 1980, engineers have been trying to use it in printed circuit manufacturing. The first successful application was by HP PCB engineers in 1983 that created an inkjet printer mechanism to serialize each PCB with a unique S/N for traceability. They used one of the UV inks HP developed that worked well on circuit boards but not suited for use on paper.

---

August 02, 2022

Happy’s Tech Talk #10: Optical Alignment/Coupon Welding for Stackups

In this month’s column, I will discuss optical alignment for pinless lamination stackup, a topic that complements the induction lamination in my November 2021 column. Pin tooling plates have been used for lamination since it first started sometime in the 1960s. I first encountered multilayer stackup when I was assigned to increase capacity for our multilayer output in 1972. This was to accommodate the growth of our computer business. Unfortunately, the explosive growth of our calculator orders in 1973 required that we look for numerous vendors to produce the six-layer logic board in the HP-35 calculator.

---

July 19, 2022

Happy’s Tech Talk #9: Radars, Missiles, and the World’s Costliest Computer

Let’s have a little fun and walk back nearly 70 years into the history of electronics and computers. What was the world’s costliest computer and why? The answer is not today’s supercomputers, nor computers built during World War II. Instead, it lies in a real-time air defense radar system built during the height of the Cold War of the 1950s that had left the U.S. extremely vulnerable to a Soviet bomber attack. This was the beginning of a North American strategic defense system, eventually known as the Semi-Automatic Ground Environment System (SAGE).

---

May 31, 2022

Happy's Tech Talk #8: Copper Etchant Regeneration

Copper has become a valuable metal, and with the growth of EV has come higher currents needed in PCB with increasing weight of copper in PCBs. This creates the need for increased copper etching and consumption of copper etchants. Today, in an effort to recoup some of that cost, increasingly more extraction and recovery units are being installed in PCB facilities around the world. Annual profit generation from recovering copper and regenerating PCB etchants has the potential to reach six figures.

---

May 02, 2022

Happy's Tech Talk #7: Next Generation Application Specific Modules

In 1965, Gordon Moore predicted that the number of transistors that could be packaged into a square inch of space would double every year for the near future. Although his projection was later revised to every 18 months, Moore’s Law has withstood the test of time for five decades. Today, we are beginning to see obstacles to this type of exponential growth due to the inherent limits associated with silicon lithography, packaging of the devices, and component placement on PCBs.

---

March 28, 2022

Happy's Tech Talk #6: Looking at the Process of Repanelization

I have spent many years in printed circuit fabrication, including nearly 20% of my career in Asia. One problem that concerns all fabricators is the issue of “How many ‘X-outs’ are allowed per assembly sub-panel array? Here are a couple of solutions I have used and encountered in my travels.

---

March 07, 2022

Happy's Tech Talk #5: Advanced Boards for Heterogeneous Integration

The expansion of IC functionality usually progresses with the shrinking of IC geometries, called “Moore's Law” after Gordon Moore who first coined the phrase. But now that geometries are below 5 nm, the costs and difficulties are creating a barrier to much further advances. So, the solution seems to be to mix IC die on the same substrate as a system-in-package (SiP) that is now called heterogeneous integration (HI).

---

January 31, 2022

Happy's Tech Talk #4: Semi-Additive Processes and Heterogeneous Integration

The semi-additive processes (SAP) are not new. I first used them with a novel process back in 1978. MacDermid had a novel SAP process called PLADD II (PLAted Additive). It was an anodized aluminum foil applied to laminates that we could easily etch off after drilling and continue with a special electroless copper for thin metallization.

---

December 20, 2021

Happy's Tech Talk #3: Photonic Soldering

Printed Electronics (PE) continues to be a growing technology. But one of the advantages, as well as a drawback is using low-cost substrates, like paper, that cannot take the temperature of solder paste reflow. Also, the inks need to be cured. One current way to cure the printed inks is with ultraviolet radiation curing, such as used with solder mask or legend inks.

---

November 23, 2021

Happy's Tech Talk #2: Induction Lamination

Multilayers have been around about as long as the printed circuit. The industry has always used heated hydraulic lamination presses to produce these multilayers, with the introduction of vacuum assist in the 1980s. But recently, with the encouragement of GreenSource Fabrication, induction lamination has been perfected by Chemplate Materials of Spain. Chemplate had introduced the use of induction-pinning by optical alignment of innerlayers for multilayer stackup in the early 2000s. This was to go with another innovative way to laminate innerlayers together—the Italian CEDAL resistance-foil vacuum-press, which had some early adopters.

---

October 22, 2021

Happy’s Tech Talk #1: Vertical Conductive Structures (VeCS)

The industry has not had many new structures in the last 60 years. Multilayers have continued to evolve with thinner materials, smaller traces / spaces as well as drilled vias. It’s been nearly 40 years since Hewlett-Packard put their first laser-drilled microvia boards into production for their innovative Finstrate process.

---

July 05, 2017

Happy’s Essential Skills: Tip of the Month—The NIST/SEMATECH e-Handbook of Statistical Methods

In the 1990s, the National Bureau of Standards was distributing a popular statistical document, the Handbook 91, written by Mary Natrella of the NBS Statistical Engineering Laboratory. A request by Patrick Spagon of the Statistical Methods Group of SEMATECH to update the NBS Handbook 91, Experimental Statistics, led to the creation of a project team from NIST and SEMATECH to create a new web-based statistical handbook including statistical software.

---

December 16, 2016

Happy's Essential Skills: Understanding Predictive Engineering

New product realization and design for manufacturing and assembly (DFM/A) have now started to become more visible as programs that can improve a company’s time-to-market and lower product costs. Many programs are underway by many companies and what is now needed is a framework to coordinate the application of these programs. This column will cover the interactions of DFM/A and the need for development of a new framework to coordinate the trade-offs.

---

November 22, 2016

Happy’s Essential Skills: Technology Awareness and Change

From Happy Holden: A long-time printed circuit-industry friend of mine, Martin Tarr, an instructor at University of Bolton, UK, is a leading expert on change. He wrote an excellent tutorial for his university course on electronics manufacturing. With permission from Tarr, I am including a portion of it here as the basis of this column, starting after the graph in Figure 2. But first, a few thoughts of my own.

---

November 03, 2016

Happy's Essential Skills: 10-Step Business Plan Process

It takes more than just a good idea to exploit that brainstorm of yours. Hewlett Packard’s “10-Step Business Plan Process” is the format to present an idea or product in a fashion that will answer most questions that management may have about a product or idea.

---

October 05, 2016

Happy's Essential Skills: Metrics and Dimensional Analysis

After 20 of my columns, readers probably realize that I am an analytical person. Thus, I dedicate this column to metrics—the method of measuring something. I mentioned the four levels of metrics in my June column "Producibility and Other Figures of Merit." I also introduced the five stages of metrics in the second part of the column "Design for Manufacturing and Assembly, Part 2." This column completes the discussion with a look at dimensionless quantities.

---

September 29, 2016

Happy’s Essential Skills: Recruiting and Interviewing

Hopefully, your career has progressed to the point that you are empowered to recruit your own team or a key person for your team. There are always technical people looking for better jobs, but many times, the most talented are busy doing their work and not looking for a new opportunity.

---

October 19, 2016

Happy's Essential Skills: Lean Manufacturing

Lean doesn’t have to exist in manufacturing alone. Lean is a fairly recent principle that can apply to all of our goods and services. For those of you not familiar with Lean, I recommend the free E-book "Survival Is Not Mandatory: 10 Things Every CEO Should Know about Lean" by Steve Williams, a regular columnist for I-Connect007.

---

September 22, 2016

Happy’s Essential Skills: Computer-Aided Manufacturing, Part 2 - Automation Examples

Semiconductor fabs like to avoid writing custom software to fit all of the idiosyncrasies of individual processing systems. So HP developed PC-10 to handle IC process equipment by separating it into general classes. SECS II was a mandatory prerequisite of the equipment before an interface to PC-10 could be developed.

---

June 10, 2016

Producibility and Other Figures of Merit

Metrics are data and statistically backed measures. It is always expedient to base decisions on data and metrics, for example, in PCB design. These measures can be density, first-pass yield connectivity or in this context, producibility. These measures are the basis for predicting and planning a printed circuit design. But what if a metric doesn’t exist? Then you can create the next best measure, the Figure of Merit

---

June 01, 2016

Learning Theory/Learning Curves

Learning is not instantaneous! Nor is progress made in a steady manner, but at a rate that is typified by one of two basic patterns. In some cases, plateaus will be seen in learning curves. These are caused by factors such as fatigue, poor motivation, loss of interest, or needing time to absorb all the material before progressing to new. This column will not go into details of how learning is achieved, but will summarize some of these theories.

---

May 04, 2016

Technical Writing

Technical writing is one of those topics that they don’t really talk about in college—at least not where I went. Writing and English has never been a strong like of mine compared to science and math. So I did my required time in English and wrote my lab reports the best I knew how.

---

May 18, 2016

Happy’s Essential Skills: Project/Product Life Cycle

The product, and or project (process) life cycle (PLC) is fundamental to a corporation intent on developing new products or processes. It sometimes is called the new product introduction (NPI) process but that is only half of the life cycle. There is product support, enhancement and eventually, obsolescence.

---

April 20, 2016

Happy’s Essential Skills: Using Web Resources

The World Wide Web is a real boon to information retrieval. The key is getting to relevant information and not being overwhelmed by the sheer number of references. When confronted with a process problem, the urgency of a solution requires that you know how to use Web resources expeditiously.

---

April 06, 2016

Failure Modes and Effects Analysis (FMEA)

Failure modes and effects analysis (FMEA) is a systematic process to evaluate failure modes and causes associated with the design and manufacturing processes of a new product. It is somewhat similar to the potential problem analysis (PPA) phase of the Kepner-Tregoe program.

---

March 17, 2016

Design of Experiments

Design of experiments (DOE) is one of the most powerful and influential engineering tools for product yield improvements, new products or processes development, or for problem solving. As mentioned in my last column, process problems led me to a career in printed circuits, and quickly solving those problems led me to a bonus stock award and a great life. Even though I knew nothing about printed circuit manufacturing processes, I was able to quickly find the root causes of all the problems and fix them. My secret? Total quality control (TQC), statistics, and DOE.

---

February 24, 2016

Problem Solving

Related to TQC and a very important role of an engineer is solving problems. Using a problem solving methodology is a job that all engineers will use sooner or later, but if you are in product or process engineering in manufacturing, it will be sooner! This was the situation that introduced me to printed circuit manufacturing.

---

February 03, 2016

The Need for Total Quality Control (Six Sigma and Statistical Tools), Part 2

The statistical representation of Six Sigma describes quantitatively how a process is performing. To achieve Six Sigma, a process must not produce more than 3.4 defects per million opportunities. A Six Sigma defect is defined as anything outside of customer specifications. A Six Sigma opportunity is then the total quantity of chances for a defect.

---

January 13, 2016

The Need for Total Quality Control (Six Sigma and Statistical Tools), Part 1

In this first of many columns covering my "Twenty-Five Essential Skills Every Engineer Needs to Learn," I will expand on each of those skills. To read the introduction to this series, which published in the January issue of The PCB Magazine. As a quick recap, here are the 25 skills that I will be writing about over the next 18 months or so, to publish every three weeks or so in the I-Connect007 Daily Newsletter.

---