NVIDIA Responds To Chip Failures, Well Sort Of

A good old fashion playground pissing match has begun over Nvidia's chip failures and "chip packaging".

The finger pointing began last week when Neil McLellan, AMD's director of packaging and interconnect technologies, offered The Tech Report his insight and opinions about Nvidia's chip failures.

McLellan claims AMD has a superior chip package design because it uses a specific set of materials, including eutectic solder bumps. In his view, Nvidia chips have failed because they use (supposedly) more fatigue-prone high-lead bumps and because, he asserted, Nvidia cares less about packaging technologies.

Chip packaging is the electronic component assembly, from solder bumps to chip insertion. The solder bumps connect the silicon GPU die to the rest of the package. It is these bumps that AMD claims "could be the cause" of Nvidia's chip failures. High-lead bumps can handle more current, but AMD thinks they're more prone to fatigue and need "comprehensive reliability engineering to be used successfully."

So far Nvidia has yet to explain its recent issues with chip failures, but late last week they did respond to AMD assertions. In a letter to The Tech Report Nvidia writes:

NVIDIA has a world class chip operations team, and has delivered over 1 Billion devices (and over 1 trillion bumps) over 14 years, in the most advanced processes, to the most demanding customers. NVIDIA is the leader in the graphics industry in innovation and has delivered technology over the years that companies like ATI and Intel have benefited from.

In his recent commentary on chip packaging, Mr. McLellan makes a number of speculative assertions about NVIDIA's people, products and philosophy. In his interview McLellan asserts that High lead bumps are more prone to fatigue. What he fails to note is that AMD currently uses High lead bumps on their CPU line -- a device well known to undergo high thermal stress, and also go through lots of power cycling.

The choice between High Lead and Eutectic is complex. There are trade-offs in using one vs. the other, as even Mr. McLellan points out. The electromigration issues associated with printed eutectic bumps can affect long term reliability of a high current device. Electromigration is when a high current causes metal to separate over time, and creates an open circuit. This is one of the main reasons why so many devices are still manufactured with High lead bumps today.

In fact, 10s of billions of semiconductor devices have been shipped with High Lead bumps by world class companies including AMD, Intel, IBM, Motorola and TI.

While McLellan implies that AMD is unique in its use of a "power redistribution layer," this isn't true. In fact use of a power redistribution layer is industry practice, and has been used in every flip chip GPU NVIDIA has shipped.

NVIDIA is committed to delivering lead free devices by the 2010 requirement. Our engineering team has been working on this important initiative for the past 18 months, and is fully engaged in this effort with our manufacturing partners.

NVIDIA uses industry standard packaging material and we have passed all industry standard (JEDEC) component package qualifications. We stand behind our products and we will continue to work with our partners to ensure the best visual experience.

While Nvidia took a defensive stance and fired back a few jabs at AMD, not once in the letter did the company explain why its GPUs are failing. The letter talked about High lead bumps and how Nvidia passes the JEDEC component package qualifications, but nowhere in Nvidia’s statement was there any kind of hint about current GPU problems. The omission of a clear response prompted, The Tech Report to contact Nvidia’s General Manager Ujesh Desai and GeForce Senior VP Jeff Fisher to get a better clarification.

"There is no evidence that this issue exists in desktops as we know them. And in fact, Mr. McLellan has no evidence to even imply that. The fact is that lead bumps—he’s saying that lead bumps will fail, and therefore you should expect to see failures on everything, and that’s completely out of balance from an educated operations guy like he is. . . . I think most industry people would say lead bumps are not a cause of failure and are in fact very reliable. And his soda-can analogy and attempt to drag in desktops is irresponsible from our view and a huge reach."

GeForce General Manager Ujesh Desai didn’t provide an extensive answer, only pointed out that the current GPU failures effect a small percentage of notebooks. As for upcoming products such as the new GeForce 9400M chipset in Apple's new MacBooks. Fisher stated plainly, "You can rest assured that Apple has been aware of all of the science that we've developed around this issue and would not be launching the most important product in their history with a product they felt was at risk." Desai later added that Nvidia is "taking the necessary steps to ensure that all the Nvidia chips currently in production don't exhibit this problem."