A criminal probe into IC substrate leader Unimicron for allegedly relabeling China-made boards as "Made in Taiwan" has spooked Taiwan's whole tech supply chain.

• Prosecutors raided Unimicron's Taoyuan headquarters and a nearby plant over suspicion the company shipped circuit boards made in China back to Taiwan and swapped on Taiwan-origin labels.
• The tip-off came from inside: staff angry over plans to close and sell an old Taoyuan plant handed over evidence of the label swapping.
• Splitting production across the strait — half-finished boards from China, final high-end work in Taiwan — is routine in the circuit board and computer hardware business, and everyone knows it sits in a gray zone.
• It only becomes illegal if the Taiwan-side work is too minor to count as real processing, or if the intent was to dodge US tariffs.
• Unimicron rode the AI boom to a share price above NT$1,000, so the case lands on one of the market's hottest names.

Outlook: How this case is decided will set the new compliance line for cross-strait production and could force a broad reshuffle across Taiwan's AI supply chain.