The Supreme Court in Taiwan has upheld a ruling that Liang Mong-song, TSMC's former senior director of the R&D lab at the foundry's Advanced Modules Technology Division, leaked trade secrets to Samsung. Mong-song worked for TSMC for 17 years and was reportedly disgruntled because he was passed up for a promotion. He resigned "to spend time with his parents" and signed a non-compete agreement that entitled him to stock bonus options.
TSMC later discovered that Mong-song was teaching at Sungkyunkwan University, a private research university with ties to Samsung. The foundry received reassurances that nothing out of the ordinary was going on, but after Mong-song received his payout he was appointed as chief technology officer at Samsung's System LSI division. During the time of his non-compete, he was teaching a three-hour class to students but spend the rest of his time "educating" Samsung employees.
ARS Technica writes TSMC believes the leak helped Samsung to gain a competitive edge more quickly. The foundry claims its trade secrets accelerated Samsung's 28nm research, and that Samsung used his know-how to move forward with next-gen processes too.
TSMC sued Liang twice and won both times, with the second of the two favorable decisions coming in spring 2014. The court at the time ruled that Liang would have to quit his job at Samsung and could not work for that company until December 31, 2015 to protect TSMC's trade secrets. The ruling was, apparently, an unprecedented one against an executive whose non-compete contract had been acknowledged as expired. The higher court affirmed that decision. TSMC has not sued Samsung directly, although it hinted to EETimes that it may file more lawsuits against Liang in the future.