Business is booming at Hua Hong Semiconductor, China’s second largest chipmaker, even as tech export controls by Western countries present major headwinds to the industry. The Shanghai-based chipmaker last week announced a plan to launch a $4 billion joint venture to expand its production lines amid strong demand for its chips. The company also has plans to raise $2.5 billion on the Shanghai STAR Market, which would be the third largest ever IPO on the city’s tech-focused bourse.