Amtech Systems Inc美股招股说明书(2026-06-03版)

Amtech Systems, Inc. 2,926,829 Shares of Common Stock We are offering 2,926,829 shares of our common stock, par value $0.01 per share (the “Common Stock”), pursuant to thisprospectus supplement and the accompanying base prospectus. The public offering price for each share of our Common Stock is$20.50 per share. Our Common Stock is listed on The Nasdaq Global Select Market (“Nasdaq”) under the symbol “ASYS.” On May 29, 2026,the last reported sale price of our Common Stock on Nasdaq was $21.27 per share. Investing in our securities involves significant risk. Please read carefully the section titled “Risk Factors” beginning onpage S-5 of this prospectus supplement. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved ofthe securities or determined if this prospectus supplement is truthful or complete. Any representation to the contrary is acriminal offense. (1) See “Underwriting” beginning on page S-9 of this prospectus supplement for additional information with respect to thecompensation payable to Titan Partners Group LLC, a division of American Capital Partners, LLC (the “Underwriter”). This offering is being underwritten on a firm commitment basis. Delivery of the shares offered hereby is expected to be made on or about June 3, 2026, subject to the satisfaction of certaincustomary closing conditions. Titan Partnersa division of American Capital PartnersThe date of this prospectus supplement is June 1, 2026 TABLE OF CONTENTS Prospectus Supplement ABOUT THIS PROSPECTUS SUPPLEMENTCAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTSPROSPECTUS SUPPLEMENT SUMMARYTHE OFFERINGRISK FACTORSUSE OF PROCEEDSDIVIDEND POLICYCAPITALIZATIONDILUTIONDESCRIPTION OF SECURITIES WE ARE OFFERINGUNDERWRITINGLEGAL MATTERSEXPERTSWHERE YOU CAN FIND MORE INFORMATIONINFORMATION INCORPORATED BY REFERENCE Prospectus ABOUT THIS PROSPECTUSSUMMARYRISK FACTORSSPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSUSE OF PROCEEDSSECURITIES WE MAY OFFERDESCRIPTION OF COMMON STOCK AND PREFERRED STOCKDESCRIPTION OF DEBT SECURITIESDESCRIPTION OF WARRANTSDESCRIPTION OF UNITSPLAN OF DISTRIBUTIONLEGAL MATTERSEXPERTSINFORMATION INCORPORATED BY REFERENCEWHERE YOU CAN FIND MORE INFORMATION ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying prospectus is part of a registration statement on Form S-3 that we filed withthe Securities and Exchange Commission (the “SEC”) utilizing a “shelf” registration process. Under this shelf registrationstatement process, we may from time to time offer to sell up to $60,000,000 of our Common Stock, preferred stock, debt securities,warrants, units or any combination of these securities in one or more transactions. We provide information to you about this offering in two separate documents that are bound together: (1) this prospectussupplement, which describes the specific details regarding this offering; and (2) the accompanying prospectus dated March 23,2026, which is included in our registration statement on Form S-3 (File No. 333-294296), as supplemented by the registrationstatement on Form S-3 MEF (File No. 333-296410) (collectively, the “registration statement”), which provides general information,some of which may not apply to this offering. Generally, when we refer to this “prospectus,” we are referring to both documentscombined. If information in this prospectus supplement is inconsistent with the accompanying prospectus, you should rely on thisprospectus supplement. However, if any statement in one of these documents is inconsistent with a statement in another documenthaving a later date, for example, a document incorporated by reference in this prospectus supplement, the statement in thedocument having the later date modifies or supersedes the earlier statement as our business, financial condition, results ofoperations and prospects may have changed since the earlier dates. We have not, and the Underwriter has not, authorized any other person to provide you with any information or to represent asto anything different from, or not contained in, or incorporated by reference into, this prospectus supplement, the accompanyingprospectus or in any free writing prospectus that we may authorize for use in connection with this offering. Neither we nor theUnderwriter take any responsibility and can make no assurance as to the reliability of, any other information that others may giveyou. We are not, and the Underwriter is not, making an offer to sell or soliciting an offer to buy our securities in any jurisdictionwhere an offer or solicitation is not authorized or in which the person making that offer or solicitation is not qualified to do so or toanyone to whom it is unlawful to make an offer or solicitation. You should assume that the information appearing in this prospectussupplement, the accompanying prospectus, the documents incorporated by reference into this prospectus supplement, and in anyfree writing prospectus th