Speed and direction – where are we going?
During APEX some weeks ago, the subtitle of the fair, was “The Velocity of Technology”. What did IPC mean with this?
To be honest, I have not asked them, but I have my own understanding. For me, the Velocity of technology has two components – speed and direction. The technology in electronics develops faster than ever. A user of mobile phones or computers may not understand at which rate electronics changes, but if you see the development of components and the complexity of today’s packages you understand the speed. Driving a car is probably one of the areas where the user comes in a direct touch of the technology development. We understand the speed when we see how fast we get new versions of smartphones and other gadgets. But, in what direction are we going? We all think that size and weight reduction is good. We get more function into the same space. At the same time we increase the functionality – a mobile phone today can do more than a desktop computer did some years ago. It has a better camera than the reasonably good full-size digital camera we still have in our drawers.
I am a PCB geek. For me, it is interesting to see how the technology development has affected the PCB, and in which direction we move? How do we see the velocity of Technology in PCBs?
(Almost) born and raised in a PCB plant
I was born in a PCB plant right outside Oslo, June 1958. Norway had no PCB factories at that time, so my father saw the potential and started to etch boards in a garage using silk screened etching resist and Ferric chloride etching. The boards had to be used fast to avoid corrosion, we only had a simple lacquer to protect the copper.
Time went by and at 20 something I was set to lead a small PTH plant. We started to use photo-imageable plating resist and Infrared reflowed tin-lead (those machines typically had a small fire every week). At that time we had no RoHS, Reach or ISO 14000 or environmental awareness. I have some stories that are better told in more private circles.
In 1992 I joined Elmatica and during the 90´s we saw some development of the PCB technology but mainly a slight miniaturization. And, frankly speaking, the PCB technology itself has not changed that much today either. We still print and etch. We still drill, but of course, we use a laser in addition to the mechanical drills. We still print solder mask, we still plate copper to achieve required thickness and through-hole connections. So, we have seen some changes, but not the speed or change of direction as in other technologies.
The Velocity of PCB technology today is still from my point of view not at the same rate as we see in components. The introduction of smaller components has almost out challenged the PCB. But only just. And, we are still in the same direction, so we can not brag too much about the velocity of the PCB Technology.
My first meeting with IPC – the giant
Before I go deeper into how I see the technology, I need to explain my “connection” with IPC.
My first APEX was in 2017. I was taken a bit off guard, by how an unknown guy from Elmatica, a Printed Circuit Broker up north, could be recognized by this ruler of electronics standardization.
I looked at IPC as a giant with no empathy for the need of companies outside the USA, especially the smaller ones. I was wrong. My experience with IPC is that all companies are welcome to contribute and have a voice, no matter the size. You just need to join a committee, have an opinion and raise your voice.
I did just that. With good help from IPC´s Lars Wallin, I volunteered for the chair of a new committee, the Automotive Addendum to IPC-6012D. Suddenly I had a voice in an organization, that from outside can look rigid and arrogant. What I found was an impressive group of engineers with an open mind to new ideas.
Don’t take me wrong, a standardization body shall be predictable and give stability. And, there are members that actively protect US interests. But, IPC is getting more and more international, and I am a part of that. (I hope no hurt feelings) So, with that background, how do I see the PCB technology and how can I contribute to the development?
Micro PCB – we need to talk about it
Today I also chair the Medical addendum, IPC-6012, and IPC-6013. In the development of this standard, we have identified PCBs used in several applications such as implants and hearing-aid that have line widths, thickness, hole sizes and other features below current tolerances and limits in today’s design, performance and acceptability standards.
Acceptable imperfections in the material that in normal PCB is acceptable may cause application failures in these products. Where volume manufacturing of a standard PCB accepts a waiver of IPC´s test frequency requirements, suppliers of these Micro PCB exceeds the standard!
Today these PCBs are made to customer requirements rather than following the IPC standard. In the other far end, we also fail to follow the standard, even for automotive and medical applications. And we all know it!! We just don’t talk about it.
Surface Contamination Testing – a hot topic
With this miniaturization, we also meet new requirements for cleanliness and contamination test methods. IPC use the term Cleanliness Testing in current standards. I call it Surface Contamination Testing because we are not really talking about cleanliness, but to control contamination levels of the solderable surface. The smaller solderable pads we have, the more we need to control the contamination level. And with increased variations in complexity and miniaturization, we may need product related acceptability levels instead of a rigid standard level for all technologies.
This is a hot topic where the industry is in a need of an urgent development. While waiting for a better solution, my automotive addendum group have found a compromise that combines current test methods in a way that gives improved reliability and better control.
We also see a development of new methods using non-solvent solutions that we believe will improve contamination testing in the near future.
MSL for PCB
One direction of the velocity of PCB technology is increased complexity and density. With this increased complexity of the PCB, controlled humidity inside the boards is vital to avoid delamination and product failure. How do we control the moisture level inside the PCB and for how long can the PCB be kept in the assembly shop floor environment before the moisture level becomes a problem? Certainly, this depends on the base materials moisture absorption rate, and some materials like polyimides do absorb moisture at a rate that requires control.
Moisture Sensitivity Levels have been in use for components a long time, as described in J-STDxxx but not for the PCB. Based on Elmatica´s internal MSL recommendation, I made a suggestion for IPC under APEX 2017 and followed up this year with the result that the committee developing IPC-1601 will further develop and implement to the next revision of the standard. I believe this will be a valuable guide for users of PCBs with high moisture absorption levels.
Specifications – more important than ever
Hand in hand with changes in the technology we must have precise specifications. Another unpaid job of mine (but a true pleasure and very exciting) is to chair CircuitData.
The other day, I received a PCB specification requiring me to follow IPC-610 class 3 and with only fractions of a sufficient PCB specification. So, a time-consuming communication started. Hopefully, we will be able to deliver what the customer needs, but insufficient specifications make the process longer and more difficult.
To succeed with increased PCB options and complexity, a detailed and correct PCB specification is a must. The future is a digital specification file such as the CircuitData file in combination with an «intelligent» production file such as IPC-2581. Such files give much more information than the good old Gerber.
The Future – what will it bring?
We cannot talk about The Velocity of PCB Technology without mentioning 3D printed circuits. I am following this from the sideline. 3D circuits included components will surely one day be a disruptive technology to the standard PCB, as we know it today with components soldered. That will be a new ballgame!
But, even 3D circuits in the early stage of its life cycle, with the current PCB Technology as I see it, will in the near future keep on following the same track towards miniaturization. What I call Micro PCBs are today touching BGA Substrate manufacturing and we need a term and a set of typical features that describes this group.
I also believe we will see an increased level of embedded technologies and complexity of mixed materials that again will challenge organizations like IPC to be upfront with the development of standards. The changes we have seen over the last 10-15 years have, unfortunately not been picked up by the standards at the same rate. And, the only way to improve the development of standards that meet the Velocity of PCB Technology is to participate.
Don’t let the technology outrun you, join in and take part in the exciting future of printed circuits.
This article was first published in the PCB Norsemen column by Elmatica in the PCB007 Magazine.
A previous blog post from Jan Pedersen.