Wirebonding is here to stay | Hacker News Reader

Wirebonding is here to stay

semiengineering.com

32 pointsmgh24 comments

> The automotive industry, with its increasing reliance on advanced electronics for everything from engine control units to driver assistance systems, demands materials that can consistently perform under challenging conditions with defects under one part per billion, which translates to one defect per billion kilometers. Copper’s inherent properties, such as its high melting point and excellent electrical conductivity, make it particularly suited for these requirements.

Wirebonding is needed because electronic circuits require a # of ICs, there isn't a simple method to connect arbitrary ICs directly, and thus circuit boards & IC packages must go in between.

Whoever finds a way to sidestep this problem in a straightforward manner, would be a rich person for sure.

In other words: "packaged" IC's are here to stay, things like flip-chip apply only to specific segments, and thus wirebonding is here to stay.

I am curious now why its not feasible to basically just solder the silicon directly to the PCB, foregoing the package. Obviously the silicon would need a bit of environmental protection, but it seems possible (probable?) to flip the die over so its typically wirebonded pads are against the board, and then same process as we have now with SMT devices, reflow oven, ready to go.

I know that some dies are super tiny and this could make it difficult at the pcb bonding level, but surely we can shrink down our usage of plastic and the alloys that go into the IC packages. Theres a lot of unused space inside an IC package, with most of it being empty or pin arms. That would allow for smaller and more dense boards.

This is done in many places. The problem is that a lot of silicon dies the die costs much more than the package. There’s a limit to how small you can make pins on a package for manufacturing onto a PCB, so if you need a certain number of pins, you either would need to grow the die (which is expensive) or switch to a packaged part.

Mobile phones today largely use chip scale packages that do not use any sort of wire bonding, for instance.

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