SEOUL, June 30 (Reuters) – A South Korean chip executive imprisoned over industrial espionage charges rejected allegations he had sought to build a copycat chip factory in China with sensitive information developed by Samsung Electronics. In a handwritten letter to Reuters, his first comments to media since he was detained on May 25, Choi Jinseog elaborated on his defence plan and said the allegations against him regarding the Xian plant were not substantiated. Prosecutors earlier this month indicted the former Samsung executive for illegally obtaining secret information to build a semiconductor plant only 1.5 km (1 mile) from a Samsung…