On the Nokia phone I just looked at is another bare die flip mounted direct to the board. Its the Cambridge Silicon Radio (CSR) 41B14 a dedicated Bluetooth transceiver.



Getting it off the board I chipped the die quite badly trying to lever it off the board before the solder balls had fully melted.  The die measures 3.7 x 3.9 mmMost of the die is digital, it is too fine for an optical microscope, I estimate this is made on a 180nm process and has about 6 layers of metal.  Dedicated Bluetooth chips are pretty obsolete today, the functionality is integrated with other functions such as the Wi-Fi transceiver.  The digital area on this chip is just under 9 mm2 each process node the linear dimensions are shrunk ~70% and the area required for logic is halved.  If this chip was fabbed on 28 nm (Which is still 2 or 3 nodes older than state of the art today, but is still a popular node for mixed digital/analog) the whole digital block would be less than 0.3 mm2  (Hence why its integrated with other functions today) that’s the power of Moore’s law and the fantastic technical progress that the semiconductor industry has continually achieved for the past 50 years.

Here is the Analog section imaged at higher resolutionThe story here though is all about art – silicon art or ‘Easter eggs’ that designers occasionally sprinkle on the chips.

The code name for this die?




Look around the die what can you find Bond’s Oddjob!Oddjob Silicon ArtThis is an impressive piece of Silicon art. Two layers of  copper have been used, in combination to get the mottled effect on the hat, or individually to bring out the facial features.

And its not the only art work on this chip. On the other side is thishappy dragon silicon art

Not sure what this is (A happy dragon?).  Somebody at CSR had too much time on their hands.  It always amazes me, miniature art that very few people will ever see.


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2 Responses to CSR ODDJOB (41B14)

  1. Evgheni says:

    With the flip chips you can quite easily separate the substrate with a sharp blade. Takes almost same time but eliminates all the messiness. The passivation on those is made really thick and durable, just need to be careful around the bonding pads. Also I just crazyglue the chip to another blade so it doesnt move much.

    Here are some pics of a more recent CSR Bluetooth chip from a Blackberry phone (done with my phone camera through my not so great microscope, that is my maximum zoom..)

    • Gary says:

      Interesting, didn’t know you could do that. I don’t think I would be patient enough if I tried to do that and suspect I would crack the chip in two trying to lever it off. Your die looks clean though, and is that large CSR logo patterned in the underfill/passivation material on your die?

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