[Photomask] Announcement of the Board's Appointment of New Chairman

1. Date of board resolution or change: 2026/06/26 2. Position (please enter 'Chairman' or 'CEO'): Chairman 3. Former incumbent's name: Chun-Chu Holding Co., Ltd. Representative Yu Chun-Kuang 4. Former incumbent's resume: Chairman of Taiwan Photomask Inc. 5. New appointee's name: Yu Chun-Kuang 6. New appointee's resume: Chairman of Taiwan Photomask Inc. 7. Nature of change (please enter 'resignation', 'dismissal', 'end of term', 'duty adjustment', 'redundancy', 'retirement', 'deceased', or 'new appointment'): New Appointment 8. Reason for change: Full board re-election due to expiration of term 9. Effective date of new appointment: 2026/06/26 10. Other matters to be disclosed: None. This announcement qualifies as material information under Article 7, Paragraph 6 of the Enforcement Rules of the Securities and Exchange Act, as it pertains to a publicly listed company and may significantly affect shareholder rights or stock prices; however, no additional disclosures are required.