费城半导体指数开盘走低，美光科技现跌超3%

Group 1 - The Philadelphia Semiconductor Index opened lower on September 19, indicating a negative market sentiment in the semiconductor sector [2] - Micron Technology experienced a decline of over 3%, reflecting potential challenges or negative news affecting the company [2] - Broadcom saw a drop of over 2%, suggesting a similar trend of weakness in the semiconductor industry [2] Group 2 - On the other hand, Marvell Technology recorded an increase of over 1%, indicating some positive movement amidst the overall decline in the sector [2] - ON Semiconductor also faced a decline of nearly 2%, further highlighting the struggles within the semiconductor market [2]