Warren Buffett this week disclosed his first significant investment in semiconductors in his long career, and the value pick is seen as a way to double down on his No.1 stock — Apple . Berkshire Hathaway built a new, $4.1 billion stake in Taiwan Semiconductor in the third quarter, becoming the biggest holder of the Taiwanese chipmaker's American depositary receipts. The disclosure sparked a big rally in the stock as Buffett made Taiwan Semi Berkshire's 10th biggest holding at the end of September. Taiwan Semi is the biggest chip producer in the world by revenue, with clients like Nvidia and…