Here are several photographs that I took last week of interesting patterns etched in copper on some printed circuit boards that I have designed over the years. The metal doesn’t have the appearance of the familiar color of a “copper penny” for two reasons. First, a copper oxidizes and tarnishes rather quickly, so the exposed copper on a printed circuit board is plated with some other non-oxidizing metal. Second, a copper penny is an metal alloy that doesn’t oxidize anything like pure copper does.
The photo above has a tin-lead solder finish over the exposed copper, but all of the remaining printed circuit boards in this post used a gold finish.
These photos were all taken by using a 100mm macro lens, with the image captured on the camera sensor very close to the actual size (1:1 magnification). I used two studio strobe lights, in 10″ x 36″ strip boxes brought in very close (less than a foot) on both sides, aimed at 45 degrees from the camera. I then used a piece of common notepad paper directly behind the subject (just outside of the frame) to bounce light back into the scene.
People aren’t very used to seeing bare printed circuit boards before the electronic components are solder to them.
The photo above is actually a lighter color of green than all of the other boards shown in this post. You can have your printed circuit boards (PCBs) fabricated in many different colors, including red, black, blue, etc., but green is by far the most common color.
Here are two land patterns that are common. The four sided one on the left is for a package type known as a Thin Quad Flat Pack (TQFP). The one on the right is for a rather large Ball Grid Array (BGA) package.
To the left of this BGA are two discrete high-speed DDR memory chips.
This footprint is for a very special type of Quad Flat Pack. The center pad is Ground, while the rectangular shapes surrounding it are for the various voltages that this chip requires. The tiny squares on the perimeter of this footprint are for attaching the actual signals of the chip to the board.
So, I’ve managed to keep my engineering role out of my web site up until this point. This post isn’t about my engineering, though; but rather the photographing of it.