It sure seems that shopping for a new car today could best be described as a dumpster fire or a crap show. How did we get here? Some models are hard to come by and dealers are at times asking $5,000, $10,000, $20,000 or even close to $100,000 over MSRP. As a former coworker would say, “Just what the actual f**k is going on?”. Is this all continued fallout from COVID, or what else is contributing to this mess? Let’s take a look at the situation with car computer chips!
The issue is complex, and I’ll focus just on one small but critical part of it. One thing that has changed more than anything in the automotive arena is the use of electronics. And, no, I’m not referring to anything that has to do with entertainment. These electronics systems control much of the operation of the vehicle, including engine and transmission operation, anti-lock brake operation and vehicle stability controls. This involves a broad swath of basic electronics components, as well as a couple of dozen different types of more complex devices, such as microcontrollers.
This is a Volkswagen ad from 1968! They were using a crude (by our standards) electronic control unit for the fuel injection. You might recall that Chrysler had attempted this very thing in 1958 with their fuel-injected 392 which used a system named Bendix Electrojector. All cars were later converted back to carburetion, as the system was just not mature enough. I suspect that a decade of electronic advances allowed VW to be successful in their endeavor. The earlier Chevy and Pontiac fuel injection systems had no electronic control, using electro-mechanical controls instead.
There were no microcontrollers in 1968, but electronic control of fuel injection was entirely possible without them. In fact, electronic control at that time wasn’t digital like it is today, but rather an electronic equivalent of the earlier electro-mechanical systems.
What’s a Microcontroller?
Today microcontrollers are found in all but the most basic electronic devices. The list includes your microwave, oven, dishwasher, clothes washer and dryer, smart television, digital camera, and many more types of units. A microcontroller is essentially a chip that contains a CPU, a vast number of interface types, timers, and possibly some Flash and/or RAM memory.
Microcontrollers are manufactured like any high-density integrated circuit, in that their circuits are ‘grown’ on silicon wafers, with many such devices on each 8″ or 12″ wafer. When the wafer is cut into individual silicon pieces, each of these are referred to as a ‘die’, with the plural being ‘dice’. Each die will be tested, mounted to a lead frame and have pins or balls attached, then finally be encapsulated.
This is an etched wafer that has some of the die removed. The blue is tape where the die are already gone and the black are die that are still in place.
The die can undergo a preliminary testing while in place on the wafer, so defective die can be discarded immediately. Die will then be fitted with wires that lead to the pins or balls that are utilized, and then encapsulated with plastic or ceramic.
This is an Infineon TriCore microcontroller. The family was introduced in 1999 for the control of automotive engines and transmissions and has been enhanced and expanded in subsequent years.
Feature Size
An integrated circuit has internal dimensions referred to as ‘feature size’, which is representative of how far apart internal components, such as transistors, are. Obviously, since we’re dealing with tens of millions of transistors (or more!) these internal dimensions are microscopic.
An IC constructed ten or twelve years ago might have been built with 20nm feature size. This is ‘nano-meter’, as 1/1,000,000,000 of a meter. For reference, a human hair diameter might be 70,000nm. ICs are constructed within the confines of an ultra-clean fab, which is an abbreviation for ‘fabrication’. A fab is built to a specific feature size, usually one toward the latest state-of-the-art size. If a company has 10nm fabs, they’re typically never going to build a new 20nm fab. If they have demand for product built on 20nm technology, they will use their existing 20nm fab(s) to meet that demand. That’s where the trouble starts for automakers.
This is a SEM (Scanning Electron Microscope) image of a single transistor, which may be one of billions on this piece of silicon.
The vast majority of microcontrollers consumed in 2022 were not products built from the latest and smallest feature sizes. These products were likely designed some years ago and are now classified as ‘mature’ or ‘legacy’ products. As long as there’s demand for these types of chips their manufacturers will continue to make them in fabs that might have reflected a state-of-the-art feature size some years ago, but not any more. What does that mean? If Infineon has tremendous demand for their microcontrollers designed in 2010 on 20nm feature size and they have one 20nm fab making these parts, this is their limit on production regardless of what the demand is. They are not going to build another 20nm fab, period. All of the ultra-high-priced equipment in a fab reflects a specific feature size, so we’re talking about a multi-billion dollar investment for a single fab! Not gonna happen.
When COVID19 hit, automakers panicked about the amount of on-hand parts they had and cancelled orders for electronic automotive components, including microcontrollers. This put them “at the back of the queue”, so to speak. Some of the fabs were transitioned to more current technologies. Bottom line: a huge demand for mature or legacy integrated circuits, with a fixed supply capacity that will not ever be increased.
Many manufacturers who use microcontrollers (not just automakers) have been faced with a quota that may or may not meet their production needs. What if you need 1,600,000 of a particular microcontroller and the maker can offer you only 800,000? Your only real course of action is to redesign your system (including software) for a different microcontroller that can be had in the numbers you need. Yeah, this is as expensive and painful as it sounds!
