Agilent Technologies Inc. announced that Alain Couder, executive vice president and COO, has decided to leave Agilent to be CEO of another company. Bill Sullivan, senior vice president and general manager of Agilent's Semiconductor Products Group, will become executive vice president and COO.   . . .   Stephan H. Schmidt, general manager at LPKF Laser & Electronics USA, has been named vice president and secretary and was elected to the company's board of directors. He will also remain general manager.   . . .   Axcelis Technologies Inc. has opened its Advanced Technology Center, a new 140,000-square-foot facility dedicated to next-generation semiconductor process development, product demonstration and customer training. Axcelis invested $31 million in the new building, located adjacent to corporate headquarters in Beverly, Mass.