China’s campaign for semiconductor self-sufficiency has entered a consolidation phase, with state-backed toolmakers swallowing smaller rivals in a bid to forge national champions aimed at defying US export curbs.In the latest move, Shanghai-listed chip equipment maker Piotech said in a filing to the stock exchange on Saturday that it planned to acquire a controlling stake in Wuxi Shangji Semiconductor.Piotech’s largest shareholder was China’s state-backed National Integrated Circuit Industry...