integrated circuit - How thick (or thin) is the die/wafer inside an IC?

There are packages as thin as 0.3 mm (maybe even less), so I was wondering how thin the actual die/wafer inside them are. I guess the package top and bottom will also need a certain thickness to be useful, so how much is left for the die?

Answer

Very thin, ~700µm (0.7mm) is close to the upper limit. Around 100µm (0.1mm) is about as thin as they get. However the size varies a lot, depending on multiple things, like the package it's made for, quality, price, and the overall size of the wafer.

Update After further research, I found that for certain applications, the wafer may be as thin as 50µm.

guess the package top and bottom will also need a certain thickness to be useful, so how much is left for the die?

An incredibly small amount, take a look at this picture and the others at the bottom.

Yamaha YMF262 audio IC decapsulated

It varies with the size of the wafer, according to wiki,

• 2-inch (51 mm). Thickness 275 µm.


• 3-inch (76 mm). Thickness 375 µm.


• 4-inch (100 mm). Thickness 525 µm.


• 5-inch (130 mm) or 125 mm (4.9 inch). Thickness 625 µm.


• 150 mm (5.9 inch, usually referred to as "6 inch"). Thickness 675 µm.


• 200 mm (7.9 inch, usually referred to as "8 inch"). Thickness 725 µm.



• 300 mm (11.8 inch, usually referred to as "12 inch"). Thickness 775 µm.


• 450 mm (17.7 inch, usually referred to as "18 inch"). Thickness 925 µm.

Basically they take a slice of silicon that's about .6mm thick (on average,) grind it, smooth it, etch it, then grind the back side.

Here's a good video to watch, How Silicon Wafers are Made. And to see how a chip is decapsulated, watch Chris Tarnovsky's video How to Reverse-Engineer a Satellite TV Smart Card.

If your interested in decapsulating chips, and close up images and probing of the die, FlyLogic's blog has some awesome posts, and great pictures!

And a few pictures of decapsulated chips,

The following 2 images are of a ADXL345 3mm × 5mm × 1mm LGA package. The first is a side X-ray. The X-ray clearly shows the presence of a separate ASIC die and MEMS die, with a hermetic cap. The internal structure of the device is more clearly seen in the SEM micrograph of the decapsulated device, in the second image.