What is the bottom layer of the CPU die?

[eatmc7]

It's a lot of fun dissecting a processor. Any good enthusiast has done it once or twice I'd like to think..... I know I've done it.

Most questions have been answered, so I could only give my experience.... but meh.

I found out later down the road, you can just purchase a CPU wafer right from e-bay.

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Even tho this looks like a nice shortcut the effort we put into the process is what the real value is imo

 

[Deleted member 185158]

Even tho this looks like a nice shortcut the effort we put into the process is what the real value is imo

Oh I agree 100%.

I've de-lidded quite a few AMD soldered processors. Some of which I do extra lapping to the silicon. My FX-5000 was lapped down as far as possible but needed just a hair of space so the cold plate doesn't hit the transistors during mounting. Was able to see through with a high powered flash light, which was interesting to see some substrate under there.

The core as mentioned is at the bottom, so yea it's suggested to lap the pin side, while I recommend to go from both sides. You'll get down far enough you can pop the wafer right out.

 

[bobbybluz]

A creamy nougat filling...

 

[Zach_01]

I think you need to see this
What are you trying to accomplish is very very hard thing as the “printed” circuitry is at nm level. The circuits and the transistors are placed to the cooling side of the die but deep enough.

 

[jaggerwild]

The bottom layer of an Intel CPU is the contact pads...............

 

[Grog6]

I disagree; the contact pads are on the top, it's the side with the metallization.

Look at the pic/image I posted above.

The "FlipChip" part is the contact pads being soldered to a substrate, instead of wire bonding.

The bottom is the Intrinsic undoped Silicon that everything else is etched/diffused into; that's 50% of the wafer or better.

See this:

Intel's 10nm Cannon Lake and Core i3-8121U Deep Dive Review

www.anandtech.com

 

[Zach_01]

I disagree; the contact pads are on the top, it's the side with the metallization.

Look at the pic/image I posted above.

The "FlipChip" part is the contact pads being soldered to a substrate, instead of wire bonding.

The bottom is the Intrinsic undoped Silicon that everything else is etched/diffused into; that's 50% of the wafer or better.

See this:

Intel's 10nm Cannon Lake and Core i3-8121U Deep Dive Review

www.anandtech.com

You got it wrong... these are just presentation pics and not the actual orientation of the die. Did you watch the 3 videos of Der8auer?

Closer to the PCB of the package are the traces of the circuitry and above them are the transistors inside (almost in the middle) of the wafer slice.
Look the static pic of Der8auer's third video this is the die upsidedown. Watch them all 3 and see for yourself. It explains all of it with detail.

 

[Grog6]

Dude, I've been in the semiconductor business for 30 years; they make a platter of intrinsic silicon, they add masks to one side, they etch or implant that side, and when they're done, it's a wafer that they cut chips from.
The diffusion and metallization is a small percentage of the thickness of the wafer/die.

I could give a Fsck about ber8aurer, I know how this shit works; you should read more.

I've made chips; not like a modern CPU, but diffusion and etching is all done from one side.

There have been tries to do etching. diffusion from both sides, but not recently.

 

[Zach_01]

they add masks to one side, they etch or implant that side, and when they're done, it's a wafer that they cut chips from.
The diffusion and metallization is a small percentage of the thickness of the wafer/die.

I agree with this...

Of course it’s done on one side, who said that it’s done to both sides?
but the lapping and exposing it’s done to the opposite side. If you defuse the die from the PCB will not see any transistor.