You may have heard the phrase “flip-chip” before: it’s a broad term referring to several integrated circuit packaging methods, the c

Flip Chips And Sunken Ships: Packaging Trick For Faster, Smaller Semiconductors

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2024-06-07 17:00:05

You may have heard the phrase “flip-chip” before: it’s a broad term referring to several integrated circuit packaging methods, the common thread being that the semiconductor die is flipped upside down so the active surface is closest to the PCB. As opposed to the more traditional method in which the IC is face-up and connected to the packaging with bond wires, this allows for ultimate packaging efficiency and impressive performance gains. We hear a lot about advances in the integrated circuits themselves, but the packages that carry them and the issues they solve — and sometimes create — get less exposure.

Let’s have a look at why semiconductor manufacturers decided to turn things on their head, and see how radioactive solder and ancient Roman shipwrecks fit in.

Very early integrated circuits were packaged in metal cans like the transistors of the day. Welded gold bond wires connected the die to the external pins. Open one of these old IC packages like a can of tuna, and the wires are plain to see. When DIP packages came about, they continued to use bond wires to connect the die to the IC pins, even though they were encapsulated in the plastic package.