Tzu-Yin Chiu, the former CEO of Semiconductor Manufacturing International (SMIC), has resigned as company vice chairman and non-executive director, according to the China-based pure-play foundry.

Chiu also resigned from SMIC's strategic advisory board, as well as his other positions at the company effective June 30, said SMIC. Personal reasons were cited for his resignation.

Chiu has been identified as a key figure in founding SMIC and assisting the foundry to once become among the world's top-3 pure-play foundries. Chiu worked under SMIC's founder Richard Chang and served as company senior VP of operations from January 2001 to July 2005. Chiu left SMIC in 2005, but held several high-ranking executive positions at other foundry companies including HuaHong NEC Electronics and Silterra.

Chiu rejoined SMIC in August 2011 and became company CEO. Chiu led SMIC until May 2017, during which the Hong Kong-listed company's market capitalization soared from HKD11.806 billion in August 2011 to HKD31.79 billion.