prior article from the inquirer:
Nvidia chips show underfill problems
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Bumpgate Electron microscopes reveal a lot
WHEN WE TOLD YOU about the 'bad bumps' in the Apple Macbook Pro 15-inch models the other day, we expected it to end there.
But as luck would have it, Nvidia pointed us to a much deeper problem that not only affects at least some of the Macbook Pro notebooks, but likely every other high Temperature of Glassification (Tg) underfill chip Nvidia makes.
Technical Background
To understand this article, you really need to understand the problem, so please read the technical three part series (Part 1, Part 2 and Part 3) explaining what the problem is and where it occurs.
Nvidia's current problem stems from its half-hearted response to its earlier problem by only changing the underfill. Nvidia said that's what it did, both near the end of our initial Macbook article and in a later Cnet article here.
In that, Nvidia's Mike Hara said, "Intel has shipped hundreds of millions of chipsets that use the same material-set combo. We're using virtually the same materials that Intel uses in its chipsets." Note the word 'virtually'. The problem with this statement - other than his analogy being misleading and not addressing Nvidia's chip design problem - is that 'virtually' in this case means Nvidia missed a key coating component in its revised chip engineering design. It is NOT the same material-set technology as Intel, AMD, ATI and everyone else we talked with uses. Unfortunately for Nvidia, the coating material it left out is critical for the life of the chip.
Before we break out the electron microscope again, we feel the need to point out some of the things that Nvidia managed not to talk about in its purported explanation of the fix. It is sad to have to point this out, but underfill does not crack, bumps do. The bumps that cracked did so for a long chain of reasons that are explained in my earlier three-part article linked above.
Earlier article:
Why Nvidia's chips are defective
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Part One A long and complex story
This the first part of a series of three articles getting to the nub of Nvidia's graphics chip woes. The series is the result of months of research conducted by diligent INQhack Charlie Demerjian, despite an in-box stuffed full of abuse. Part two can be found here and Part Three is here.
NVIDIA HAS RECENTLY been saying a lot about how it's chips are not bad, and giving people reasons about why the problem is contained. Unfortunately, these disingenuous half-truths don't stand up to an explanation of why this problem is happening.
Sounds like a design rule violation on the passivation layer or lack there of.
Nvidia continues to have problems with its fab vendor and/or communication.