Substandard raw materials responsible for low yield rate: TSMC

The logo of Taiwan Semiconductor Manufacturing (TSMC) is seen in this undated file photo. (NOWnews file photo)

TAIPEI (CNA) — Taiwan Semiconductor Manufacturing Co. (TSMC), the world’s largest contract chipmaker, on Jan. 29 announced that the low yield rate of silicon wafers produced at its 14B fab in Tainan, southern Taiwan was caused by substandard photo-resistant materials.

The company saw its stock price plunge on the Taiwan Stock Exchange (the Taiex) Tuesday after it reported defective silicon wafers from the Tainan fab the previous day when it said the chemical materials supplied to the facility fell short of specifications, impacting more than 10,000 wafers.

In its latest statement on the incident, TSMC explained that the company identified the low yield rate of wafers produced using 12-nano and 16-nano processes at the 14B fab on Jan. 19.

After an investigation, it found the problem was caused by a batch of substandard photo-resistant materials, TSMC said, noting that the products were from “a well-performing” supplier with which the company has worked for years.

However, batch specifications fell short of previous deliveries, TSMC said, without naming the supplier. The company stopped using the substandard materials at once and informed all affected clients, TSMC added.

As the output gap will be largely made up in the first quarter, the glitch is not expected to prevent the company achieving its first quarter operational goal of NT$7.3 billion to NT$7.4 billion in revenues, a drop of 22 percent quarter-to-quarter, TSMC said. TSMC’s stock price fell NT$6.5, or 2.84 percent to NT$222.5 per share on the Taiex Tuesday.

By Chang Chien-chung and Elizabeth Hsu