TAIPEI, March 26 : Shares of Taiwanese memory chip maker Nanya Technology opened limit-up 10 per cent on Thursday after raising about $2.5 billion in a private placement from SanDisk Technologies and others to expand advanced chip production. The fundraising comes as chipmakers boost production capacity and their customers seek to lock in supplies through tie-ups amid a global memory chip shortage triggered by the artificial intelligence boom. That in turn has tightened supplies to a number of