UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 1)*

Amtech Systems, Inc.

(Name of Issuer)

Common Stock, par value $0.01 per share

(Title of Class of Securities)

032332504

(CUSIP Number)

Privet Fund LP

Attn: Ryan Levenson

79 West Paces Ferry Road

Suite 200B

Atlanta, GA 30305

With a copy to:

Rick Miller

Bryan Cave Leighton Paisner LLP

1201 W. Peachtree St., 14th Floor

Atlanta, GA 30309

Tel: (404) 572-6600

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

January 28, 2020

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition which is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(e), (f) or (g), check the following box ¨.

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See § 240.13d-7 for other parties to whom copies are to be sent.

*       The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Reference is hereby made to the statement on Schedule 13D filed with the Securities and Exchange Commission on November 25, 2019 (the “Schedule 13D”), with respect to the Common Stock, par value $0.01 per share (the “Common Stock”), of Amtech Systems, Inc., an Arizona corporation (the “Issuer”). Capitalized terms not otherwise defined herein are used as defined in the Schedule 13D. The Reporting Persons hereby amend and supplement the Schedule 13D as follows.

Item 3. Source and Amount of Funds or Other Consideration.

Item 3 is hereby amended and restated in its entirety to read as follows:

The aggregate purchase price of the 543,388 shares of Common Stock beneficially owned by the Reporting Persons is approximately $3,051,288.42 not including brokerage commissions, which was funded with partnership funds of Privet. Privet effects purchases of securities primarily through margin accounts maintained for it with prime brokers, which may extend margin credit to it as and when required to open or carry positions in the margin accounts, subject to applicable federal margin regulations, stock exchange rules, and the prime brokers’ credit policies.

Item 5. Interest in Securities of the Issuer.

Items 5(a), 5(c) and 5(e) are hereby amended and restated in their entirety to read as follows:

(a) As of the date of this filing, the Reporting Persons beneficially own 543,388 shares (the “Shares”), or approximately 3.78%, of the outstanding Common Stock of the Issuer (calculated based on information included in the Proxy Statement filed by the Issuer on January 24, 2020 which reported that 14,391,122 shares of Common Stock were outstanding as of January 21, 2020).

(c) Except as set forth on Schedule I, no transactions in the Common Stock were effected during the past 60 days by the Reporting Persons, or, to the best of the knowledge of the Reporting Persons, by any of the other persons named in response to Item 2, if any.

(e) On June 28, 2020, the Reporting Persons ceased to be the beneficial owner of more than five percent (5%) of the Common Stock of the Company.

CUSIP No. 032332504

Page 6 of 7 Pages

Signature

After reasonable inquiry and to the best of my knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

SCHEDULE 1

Shares Acquired or Sold by the Reporting Persons in the Last 60 Days or Since Their Most Recent Schedule 13D Filing: