Phil Zarrow: Seth, InFORMS®—it's a new type of preform.
Seth Homer: It is. InFORMS® are a departure from standard bulk solder. The addition of a matrix that resides in the joint, that doesn't reflow, is definitely a differentiator.
Phil Zarrow: What is the application for InFORMS®?
Seth Homer: InFORMS® were developed specifically for standoff control for power electronics. So where people are attaching a substrate to a baseplate, large-area soldering can actually increase die tilt, or, I should say, substrate tilt. So those areas of stress concentration lead to delamination during operation, so you take a hit in reliability. InFORMS® were originally designed for that, but, after further development, adds something else to the equation as well.
Phil Zarrow: So let's talk about the composition of InFORMS®, how is it different, and how aids in these areas?
Seth Homer: InFORMS® are presented to the joint along with the solder—at the same time. The entire thing is re-flowed. The matrix actually develops an intermetallic relationship with the bulk solder, thereby making it a composite material that is stronger. So creep resistance and reliability can be increased two to four times.
Phil Zarrow: So we have the advantages of much improved collinearity and also obviously better control with regard to thermal coefficient of expansion (CTE).
Seth Homer: The addition of the matrix is actually a strengthening component, so the development of other geometries are allowing us to get into to die-level attach, as well, and thereby allowing for strengthening of the joint there.
Phil Zarrow: What size ranges do InFORMS® come in?
Seth Homer: That's a really good question. We provide six different geometries, Z-direction thicknesses, all the way from eight mils down to three mils. The other component of geometry of the matrix is the mesh density. And, that really is a discussion that needs to be had on a case-to-case basis depending on the customer's needs.
Phil Zarrow: Okay, adding these to the board, the application, how is that accomplished?
Seth Homer: Essentially the same way that it would be accomplished with a regular solder. The beauty of InFORMS® is the fact that they’re a drop-in replacement. Other methods of standoff control require either equipment or redesigns of baseplates or substrates—building in a standoff into the material. So tape & reel, waffle pack, tray pack… For the power electronics industry, one of the main methods of presenting solder to the joint is cutting ribbon, and there's equipment out there that does it. InFORMS® come as a ribbon, as well, so these are drop-in replacement offerings.
Phil Zarrow: Seth, where can we find out more information on InFORMS®?