NVIDIA GeForce 8500M series is the troubled chip

Earlier this week NVIDIA announced it will take a $150 million to $200 million charge against its cost of revenue to resolve issues related to die/packaging materials used in previous generation notebook products.

The graphics firm didn't share a lot of details about the problem but DigiTimes investigated the matter and found out the GeForce 8500M series, which was launched last year, is the troubled chip. The site heard the problem is most likely related to either the solder bumping process used by one (or more) of NVIDIA's manufacturing partners or the company's PCB substrate supplier(s).

Sources at foreign institutional investors in Taiwan indicated that the defective products were Nvidia Geforce 8500M-series graphics chips launched in 2007, and that the problem was caused by related bump processing. Taiwan Semiconductor Manufacturing Company (TSMC), Advanced Semiconductor Engineering (ASE) and Siliconware Precision Industrial (SPIL) all provide bump processing services to Nvidia.

When ask for comment by Digitimes TSMC declined citing client confidentiality, while ASE and SPIL both claimed to know nothing about the issue because the defective chips are older generation products.

On the other hand, some industry insiders believe the problem might have been caused by PCB substrates supplied by Nay Ya Print Circuit Board (NPC) or Phoenix Precision Technology (PPT).

The sources speculated that the problem could be that the green paint used by NPC in PCB production might have lower than expected heat resistance, or that the adhesiveness of ABF (Ajinomoto Build-up Film)-based substrates produced by PPT might not be strong enough.