Subsequent Event	12 Months Ended
Sep. 30, 2025
Subsequent Events [Abstract]
Subsequent Event	18. Subsequent Event Stock Repurchase Program On December 9, 2025, the Board of Directors (the “Board”) of Amtech Systems, Inc. (the “Company”) authorized and approved a share repurchase program for up to $5 million of the currently outstanding shares of the Company’s common stock over a period of 12 months. Under the stock repurchase program, the Company intends to repurchase shares through open market purchases, privately-negotiated transactions, block purchases, 10b5-1 plans, or otherwise in accordance with applicable federal securities laws, including Rule 10b-18 of the Securities Exchange Act of 1934 (the “Exchange Act”). The Company cannot predict when or if it will repurchase any shares of common stock as such stock repurchase program will depend on a number of factors, including constraints specified in any Rule 10b5-1 trading plans, price, general business and market conditions, and alternative investment opportunities. Information regarding share repurchases will be available in the Company’s periodic reports on Form 10-Q and 10-K filed with the Securities and Exchange Commission as required by the applicable rules of the Exchange Act. This report contains forward-looking information, as that term is defined under the Exchange Act, including information regarding purchases by the Company of its common stock pursuant to any Rule 10b5-1 trading plans. By their nature, forward-looking information and statements are subject to risks, uncertainties, and contingencies, including changes in price and volume and the volatility of the Company’s common stock; adverse developments affecting either or both of prices and trading of exchange-traded securities, including securities listed on the Nasdaq Global Select Market; and unexpected or otherwise unplanned or alternative requirements with respect to the capital investments of the Company. The Company does not undertake to update any forward looking statements or information, including those contained in this report.

Subsequent Event

12 Months Ended

Sep. 30, 2025

18. Subsequent Event

Stock Repurchase Program

On December 9, 2025, the Board of Directors (the “Board”) of Amtech Systems, Inc. (the “Company”) authorized and approved a share repurchase program for up to $5 million of the currently outstanding shares of the Company’s common stock over a period of 12 months. Under the stock repurchase program, the Company intends to repurchase shares through open market purchases, privately-negotiated transactions, block purchases, 10b5-1 plans, or otherwise in accordance with applicable federal securities laws, including Rule 10b-18 of the Securities Exchange Act of 1934 (the “Exchange Act”).

The Company cannot predict when or if it will repurchase any shares of common stock as such stock repurchase program will depend on a number of factors, including constraints specified in any Rule 10b5-1 trading plans, price, general business and market conditions, and alternative investment opportunities. Information regarding share repurchases will be available in the Company’s periodic reports on Form 10-Q and 10-K filed with the Securities and Exchange Commission as required by the applicable rules of the Exchange Act.

This report contains forward-looking information, as that term is defined under the Exchange Act, including information regarding purchases by the Company of its common stock pursuant to any Rule 10b5-1 trading plans. By their nature, forward-looking information and statements are subject to risks, uncertainties, and contingencies, including changes in price and volume and the volatility of the Company’s common stock; adverse developments affecting either or both of prices and trading of exchange-traded securities, including securities listed on the Nasdaq Global Select Market; and unexpected or otherwise unplanned or alternative requirements with respect to the capital investments of the Company. The Company does not undertake to update any forward looking statements or information, including those contained in this report.