** Shares of Amkor Technology Inc AMKR.O jump 14.5% to $35 pre-market
** Semiconductor packaging firm says it has begun work on new outsourced semiconductor advanced packaging and test facility in Arizona
** AMKR also raises investment into the facility by over $5 billion to total $7 billion
** Analysts tracking stock rate it "hold" on average; median PT is $25 - data compiled by LSEG
** Stock up 19% so far this year, up to last close
(Reporting by Nandan Mandayam in Bengaluru)
((Nandan.Mandayam@thomsonreuters.com; Mobile: +91 9591011727;))