68000 microprocessor anatomy

[Apostrophe]

Hi, just a very basic question here; I've done some research, but can't find the answer to this, so I figured that someone here would know...

The Motorola 68000 microprocessor chip found on the logic boards of early compact Macs is about 1"X4" in size. If I were to take the plastic black casing off, how much of the chip is actually the silicon 'chip', the actual wafer with the 68,000 transistors etched onto it?

-Apostrophe

 

[Megas3300]

Maybe If I can find a new logic board for My 128k, we will find out first hand!

 

[porter]

44mm2 (as in 44 square millimetres) so approximately 7mm by 7mm, or just over a 1/4" by 1/4".

 

[Apostrophe]

Great, thanks!

 

[JDW]

And here is a die photo.

 

[Apostrophe]

Hi,

Excuse me for my lack of knowledge on Integrated Circuit terms, but what exactly is a 'die'?

I keep coming across that term, and I have no idea what it means.

-Apostrophe

 

[macgeek417]

I believe its the actual silicon chip contained within the ceramic

 

[porter]

http://en.wikipedia.org/wiki/Die_(integrated_circuit)

 

[tomlee59]

Hi,
Excuse me for my lack of knowledge on Integrated Circuit terms, but what exactly is a 'die'?

I keep coming across that term, and I have no idea what it means.

-Apostrophe

A "die" is just another term for "chip," where "chip" here refers to the actual unpackaged silicon. When you produce chips, you make wafers of them at a time. Then you slice and dice them into separate chips. The singular of "dice" is "die," so that's how the term evolved.

Today, "chip" can mean the unpackaged silicon (the die), or the fully-packaged integrated circuit, pins or bumps and all. A die only refers to the silicon piece of it.

 

[Apostrophe]

Awesome! Thanks everyone, that clears things up!

-Apostrophe

 

[trag]

Things are a little clearer on the PPC601 (not sure about the later models) because the die was mounted in a flip chip configuration, where the die is turned upside down and attached to the package. So on a PPC601, there's a little rectangle in the middle of the full packaged chip. That little rectangle is the silicon die. Everything else is the package which connects conductors to metal bumps on the die and runs them out to the edge of the chip as wires.

If you have an x100 model (or original 7500 CPU card) laying around, you can see this by removing the heat sink and cleaning off the heat sink compound--but be sure to apply fresh compound when you're done gazing.

 

[porter]

For the curious find an old EPROM like a 2732 or similar, they have a little quartz window and you can see the chip proper without distruction. You can erase the eprom if you leave it out in sunlight for a week or so.

Years ago, (over 20) we made some early digital cameras by removing the top of some DRAM chips...