EXHIBIT 10(l)



TRUST AGREEMENT



Between

Spire Corporation

and

Riggs Bank
N.A.

Trustee



This Trust Agreement, hereinafter referred to as the Agreement, is made as of the date appearing at the end hereof but effective for all
purposes as of April 1, 2004, between Spire Corporation, a corporation organized under the laws of Massachusetts, hereinafter referred to as the Employer, and Riggs Bank N.A., a national banking association organized and existing under
the laws of the United States and having its principal office and place of business in Washington, D. C., hereinafter referred to as the Trustee.



WITNESSETH



WHEREAS, the Employer has established the Spire Corporation 401(k) Profit Sharing Plan, hereinafter referred to as the Plan, for the
benefit of eligible employees and alternate payees and beneficiaries of deceased eligible employees, hereinafter referred to as Participants, and



WHEREAS, the Plan provides that the assets thereof be held, IN TRUST, by a trustee, subject to the provisions of a declaration of trust dated March
1, 1985, as the same may be amended, between the Employer and a trustee or trustees;



WHEREAS, the Employer wishes to appoint the Trustee to hold and administer the Plan assets as a directed trustee pursuant to the terms of this Trust Agreement, which shall be deemed to amend and supercede the
aforementioned 1985 declaration of trust, and the Trustee is willing to serve in such capacity;



NOW THEREFORE, the Employer and the Trustee agree as follows:



1. Fund.



The Employer hereby appoints the Trustee to serve as Trustee for the assets of the Plan, and establishes with the Trustee a trust account or accounts
consisting of such sums of money and such other property acceptable to the Trustee as shall from time to time be paid or delivered to the Trustee pursuant to this Agreement. All such money and property, all investments made therewith and proceeds
thereof and all earnings and profits thereon, less any payments or distributions made by the Trustee pursuant to the terms of this Agreement, are referred to herein as the Fund.



2. Contributions and Distributions.



(a) The Employer shall make contributions to the Fund pursuant to the terms
of the Plan in such manner as agreed to by the Trustee. The Trustee shall have no duty to determine or to enforce payment of any contribution due under the Plan or any responsibility for the adequacy of the funding policy adopted by the Employer to
meet and discharge liabilities under the Plan.



(b) The Trustee
shall make such payments and distributions as directed in writing by the Plan Administrator (as defined in the Plan) or its delegate. Such written direction of the Plan Administrator (or its delegate) shall be deemed a certification that such
payments and distributions comply with the terms of the Plan and the Employee Retirement Income Security Act of 1974 as now in effect or as it may hereafter be amended (hereinafter referred to as ERISA), and (except as provided in
Section 20 of this Agreement), the Trustee shall have no duty to verify that such payments and distributions comply with the provisions of the Plan and applicable law.



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3. Investments.



(a) The Plan Administrator (or its delegate) by written direction to the Trustee shall designate the investment options to
be offered to the Participants and an agent (the Agent), who shall be authorized to determine the allocation of available moneys for investment among such investment options and initiate transactions for such investment. The Trustee
shall have no duty to question any action or direction of the Plan Administrator (or its delegate) or its Agent or any failure to give directions, or to review the securities which are held pursuant to the Plan Administrators (or its
delegates) directions, or to make any suggestions to the Plan Administrator (or its delegate) on the investment and reinvestment of, or disposing of, such assets. The Trustee shall not have any liability or responsibility for any loss to or
depreciation of such assets because of the purchase, retention or sale of assets in accordance with the Plan Administrator (or its delegate) direction.



(b) If authorized by the Plan Administrator (or its delegate), the Trustee may invest available cash balances with itself so that the cash balances may be
credited with interest paid in accordance with the Trustees usual procedures. However, nothing herein shall confer any authority or obligation upon the Trustee to invest or reinvest such cash balances until the Trustee receives directions
acceptable to the Trustee from the Plan Administrator (or its delegate).



(c) The transactions directed by the Plan Administrator (or its delegate) shall be made upon such terms and conditions and from or through such principals and agents, including the Agent, as the Plan Administrator (or
its delegate) shall direct, provided that no transaction shall be executed through the facilities of the Trustee without its consent.



(d) The Trustee shall execute any instruments necessary or appropriate to enable the Trustee to carry out its powers hereunder. The Plan Administrator (or
its delegate) shall give all directions to the Trustee in writing, signed by such person or persons designated in writing by the Plan Administrator, provided that the Trustee may accept oral directions for purchases or sales from such designated
person or persons subject to confirmation in writing. The Trustee is authorized to act and rely upon any document delivered to it by facsimile transmission as if such documents were originals, provided that the Trustee may request that the original
document be subsequently delivered to it by mail.



(e) The
Trustee shall not be liable for and the Employer will indemnify and hold harmless the Trustee (and any employee of the Trustee) of and from all liability or expense (including reasonable counsel fees) because of (1) any investment action taken or
omitted by the Trustee in good faith in accordance with any direction of the Plan Administrator (or its delegate) or any investment inaction in the absence of directions from the Plan Administrator (or its delegate), or (2) any investment action
taken in good faith by the Trustee pursuant to an order to purchase or sell securities placed by the Plan Administrator (or its delegate) directly to a broker or dealer.



4. Insurance Investment Contracts. The Plan Administrator (or its delegate) may direct the Trustee to invest all or a
portion of the Fund in contracts issued by insurance companies, including but not limited to contracts under which the insurance company holds Fund assets in a separate account or commingled separate account managed by the insurance company.
Notwithstanding any provisions of such contract, the Trustees responsibilities shall be limited solely to receiving and forwarding monies and other properties to and from the insurance company as the Plan Administrator (or its delegate)
directs. The Plan Administrator (or its delegate) shall assume all other duties, responsibilities, rights, or obligations under the contract not expressly assumed by the insurance company for the management, control, or administration of such
assets. The Trustee may rely upon statements made by any insurance company as they affect the Trustees duties hereunder. The Trustee shall not be liable or responsible for the acts or omissions of any insurance company for the portion of the
Fund over which the insurance company has control.



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5. Investment Powers. The Trustee shall have the following powers and authority in the
administration of the Trust; provided, however, that such powers and authority shall be exercised by the Trustee only upon the receipt of direction from the Plan Administrator (or its delegate) or the Agent:



(a) To invest and reinvest the Fund free from any limitations imposed by
state law on investments of trust funds and without distinction between income and principal in any property, real or personal, including, but not limited to the following: common and preferred stocks (including stock of the Employer, or any
associated, affiliated or subsidiary company of the Employer, to the extent permitted by ERISA; governmental obligations; equipment trust certificates; participation certificates; investment companies or trusts; collateral trust notes; savings and
time deposits (including any deposit bearing a reasonable rate of interest that a bank or similar financial institution named in this Agreement makes in itself or an affiliate); mutual funds including open-end investment companies registered under
the Investment Company Act of 1940 to which Trustee or an affiliate provides investment advisory, investment management or other similar services for a fee; commercial paper including participation in variable amount notes of borrowers of prime
credit; leasebacks; mortgages and other interests in realty (to the extent permitted by ERISA); corporate bonds, debentures, notes, and other evidences of indebtedness, secured or unsecured (including bonds, debentures or notes, whether secured or
unsecured, of the Employer or any associated, affiliated or subsidiary company of the Employer, to the extent permitted by ERISA); non-income producing securities or property; options; and participation in any group or common trust funds held or
maintained by the Trustee for commingling assets of participating trusts and exempt from Federal Income tax including, but not limited to, any group or common trust fund which is qualified under the provisions of Section 401(a) of the Internal
Revenue Code of 1986 as amended or any successor provisions thereto, the instrument of trust creating any such qualified group or common trust fund, to the extent of the Funds equitable share thereof, being deemed adopted hereby.



(b) To vote in person or by proxy, general or special, any securities held
in the Fund; to exercise conversion privileges, subscription rights or other options; to participate in reorganizations or other changes in property rights.



(c) To hold property hereunder in bearer form or to hold such property in its own name or the name of its nominee, to combine certificates representing
investments hereunder with certificates of the same issue the Trustee holds in other fiduciary capacities, to hold securities in definitive form on a segregated or non-segregated basis or with a correspondent bank or depository (including The
Depository Trust Company (New York)) on a segregated or non-segregated basis with such correspondent bank or depository empowered to hold registrable securities in its nominee, to hold obligations of the United States government and agencies thereof
on a book entry basis at the appropriate Federal Reserve bank; provided that the books and records of the Trustee shall at all times show that all such property and securities are held hereunder, and the trustee shall not hold any property or
securities hereunder in the same account as any individual property of the Trustee. The Trustee shall not maintain the indicia of ownership of any assets of the Plan outside the jurisdiction of the district courts of the United States.



(d) To enter into contracts for or to make commitments either alone or in
company with others to purchase or sell at any future date any property acquired for the Fund or which it may be authorized to acquire under this Agreement.



(e) In consultation with Plan Administrator (or its delegate), to enforce by suit or otherwise, or to waive its rights on behalf of the Fund, and to
defend claims asserted against it or the Fund; to compromise, adjust and settle any and all claims against or for the Fund.



(f) To borrow money from any source as may be necessary or advisable to effectuate the purposes of the Fund.



(g) To organize corporations under the laws of any state for the purpose of
acquiring or holding title to any property for the Fund.



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(h) To employ and pay suitable agents and counsel provided that the Trustee is reimbursed for such
reasonable expenses by the Employer.



(i) To do all other acts
that the Plan Administrator (or its delegate) may deem necessary or proper to carry out any of the foregoing powers or otherwise in the best interests of the Fund.



6. Income Collection and Payments on Instructions. The Trustee shall collect the income from the Fund and shall make
payments from the Fund in such amounts and in such manner as the Plan Administrator (or its delegate) may direct from time to time in writing; but the obligation of the Trustee to make payments hereunder shall not be for an amount in excess of the
realizable value of the Fund at the time, and such directions need not specify the application to be made of such payments.



7. Trustees Records and Statements. The Trustee shall keep accurate and detailed records of all transactions hereunder, and all its accounts,
books and records relating thereto shall be open at all reasonable times to the inspection of the Employer or the Plan Administrator (or its delegate). The Trustee shall furnish its usual reports of cash transactions and statements of assets and
such other reports as the Plan Administrator (or its delegate) and the Trustee mutually agree.



8. Reports and Collective Fund Valuation.



(a) Within 90 days after the close of the Plans fiscal year or such other period as the Plan Administrator (or its delegate) and Trustee may agree and within 90 days after either the resignation or the removal
of the Trustee as provided herein, the Trustee shall file with the Plan Administrator (or its delegate) a written account setting forth all investments, receipts, disbursements and other transactions effected by it during such fiscal year or during
the period from the close of the last fiscal year to the date of such resignation or removal.



(b) Whenever the Fund holds units of any group or common trust fund, and the Trustee must value the Fund, the Trustee may use the most recently available unit value determined in accordance with the rules and
regulations pertaining to each group or common trust fund.



(c)
If the Trustee shall be required to value the assets of any portion of the Fund under the direction of the Plan Administrator (or its delegate), the Trustee may rely for all purposes of this Agreement on any valuation that the Plan Administrator (or
its delegate) furnishes to the Trustee.



9. Certifications,
Instructions and Indemnification.



(a) Any action of the
Employer pursuant to any of the provisions of this Agreement shall be evidenced by a copy of a resolution of the Board of Directors of the Employer, certified by the Secretary or an Assistant Secretary of the Board of Directors and the Trustee shall
be fully protected in relying upon such resolutions so certified to it as actions of the Employer. The Employer shall promptly certify to the Trustee from time to time the name or names of the members of committee serving as the Plan Administrator,
together with specimen signatures of the committee members or of those persons to whom the Plan Administrator has delegated authority with respect to Plan administrative matters involving the Trustee, and for all purposes hereunder the Trustee shall
be entitled to rely upon such certificates as evidence of the identity and authority of the Plan Administrator to act for the Employer and of the identity and authority of the delegates to act for the Plan Administrator. In the absence of any
written notification of change, the Trustee may assume that the persons authorized to act are the same as last reported to the Trustee. Any communication to the Trustee by the Plan Administrator (or its delegate) shall be in writing and shall be
signed by such person as may be designated in writing by the Employer or Plan Administrator to sign on its behalf. The Trustee shall not be liable and the Employer shall indemnify and hold harmless the Trustee of and from any liability or expense
(including Trustee reasonable counsels fees) because of any disbursement of any part of the Fund made by the Trustee in good faith at the direction of the Plan Administrator (or its delegate). or any action taken or omitted in accordance with
directions of the Employer or the Plan Administrator (or its delegate).



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(b) The Employer shall indemnify and save the Trustee (and any employee of the Trustee) harmless from and
against any liability, cost or other expense, including but not limited to the payment of reasonable attorneys fees, that the Trustee may actually incur in connection (whether direct or indirect) with this Agreement or the Plan unless such
liability, cost or other expense arises from the Trustees own negligence or willful misconduct. The Trustee shall indemnify and save the Employer and/or the Plan Administrator (or its delegate) harmless from and against any liability, cost or
other expense, including, but not limited to the payment of reasonable attorneys fees, that the Employer and/or the Plan Administrator (or its delegate) may actually incur in connection (whether direct or indirect) with this Agreement or the
Plan which arises from the Trustees proven sole negligence or willful misconduct in connection with (a) a delay in the investment of funds after Trustee receives proper directions from the Plan Administrator, or (b) a delay in payment of funds
after Trustee receives proper directions from the Plan Administrator. The Employer recognizes that a burden of litigation may be imposed upon the Trustee as a result of some act or transaction relating to the Plan or Trust for which the Trustee has
no responsibility or over which it has no control under this Agreement. Therefore, the Employer agrees to indemnify and hold harmless and, if requested, defend the Trustee (and any employee of the Trustee) from any expenses (including reasonable
counsel fees, liabilities, claims, damages, actions, suits or other charges) incurred by the Trustee (or its employees) in defending against any such litigation.



10. Expenses and Compensation. All expenses of the Trustee relating to the acquisition, servicing, and disposition of
investments constituting part of the Fund, and all taxes of any kind whatsoever that may be assessed under existing or future laws against the Fund or the income thereof shall be charged to the Fund. All other expenses incurred by the Trustee in the
administration of this Agreement, including fees for legal services rendered to the Trustee (whether or not rendered in connection with a judicial or administrative proceeding and whether or not incurred while it is acting as Trustee), such
compensation to the Trustee as may be agreed upon from time to time between the Trustee and the Employer, and all other proper charges and disbursements of the Trustee, shall be paid from the Fund unless paid by the Employer. Anything in the
preceding sentences to the contrary notwithstanding, the Employer shall reimburse the Trustee for any such expenses incurred by it if for any reason such expenses cannot be paid out of the Fund or, if paid by the Fund, are subsequently required to
be restored to the Fund or to the Plan. Nothing in this Section 10 shall be deemed to prevent the Fund from bearing any management fees and expenses that may be charged on any investment made in or through a group or common trust fund, an insurance
company, an investment company or any other medium for group investment. Except as otherwise provided under ERISA or the Code, to the extent that the Fund is invested in mutual funds to which Trustee or an affiliate provides investment advisory and
other services, Trustee or an affiliate may receive fees from the mutual funds for such services.



11. Removal and Resignation.



(a) Resignation or removal of the Trustee will not terminate the Trust. In the event of any vacancy in the position of Trustee, whether by the resignation
or removal of the Trustee, the Employer will appoint a successor trustee and such appointment will become effective upon the acceptance of its office by the successor trustee. If the Employer does not appoint such a successor within 60 days after
notice of resignation or removal is given, the Trustee may apply to a court of competent jurisdiction for such appointment. Each successor Trustee so appointed and accepting a Trusteeship hereunder will have all the rights and powers and all of the
duties and obligations of the original trustee under the provisions hereof.



(b) The Employer may remove the Trustee at any time upon sixty-(60) days notice in writing to the Trustee unless the Trustee agrees to a shorter period. The Trustee may resign at any time upon sixty (60) days notice
in writing to the Employer unless the Employer agrees to a shorter period. Upon such removal or resignation of the Trustee, the Employer shall appoint a successor trustee and, upon the successor trustees acceptance of such appointment, the
Trustee shall assign, transfer and pay over to such successor trustee the funds and properties under its control, or if the Employer establishes an alternative funding medium, the Trustee shall assign, transfer and pay over the funds and properties
under its control as the Employer directs. The Trustee is authorized, however, to reserve such amount as it may deem advisable for payments of fees and expenses for the settlement of its account or otherwise, and any balance of such reserve
remaining after the payment of such fees and expenses shall be paid as the Employer directs.



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(c) No trustee will be liable or responsible for anything done or omitted to be done in the
administration of the Fund before it became Trustee or after it ceases to be Trustee.



12. Amendment. The Employer and the Trustee may amend this Agreement at any time by a written agreement between them; provided, however, that no such amendment shall make it possible for any part of the corpus
or income of the Fund to be used for or diverted to purposes other than the exclusive benefit of Participants or their beneficiaries or defraying the reasonable expenses of administering the plan.



13. Termination. The Employer reserves the right at any time to
terminate this Agreement upon sixty (60) days notice to the Trustee unless the Trustee agrees to a shorter period. In the event of such termination of this Agreement (or of the Plan under which it was established), the Trustee shall continue to
administer the Fund as herein provided until all of the purposes for which it has been established have been accomplished or dispose of the Fund after the payment or other provision for all expenses incurred in the administration and termination of
the Trust (including any compensation to which the Trustee may be entitled), all in accordance with the written order of the Employer or any successor thereto. Until the final distribution of such Fund, the Trustee, and the Employer shall continue
to have and exercise all of the powers and discretions conferred upon them by this Agreement.



14. Successor Employer and Merger or Consolidation of Trustee. The term Employer shall include its successors in business, and the term
Trustee shall apply to any trustee or trustees acting hereunder, whether signatory hereto or subsequently designated by the Employer. Any corporation into which the Trustee may be merged or with which it may be consolidated, or any
corporation resulting from any merger, reorganization, or consolidation to which the Trustee may be a party, or any corporation to which all or substantially all of the trust business of the Trustee may be transferred shall be the successor of the
Trustee hereunder without the execution or filing of any instrument or the performance of any further act.



15. Return of Contributions. Contributions are conditioned upon deductibility under Section 404 of the Internal Revenue Code of 1986 and to the
extent such deductions are disallowed, or are made by a mistake of fact, the Trustee may return said contribution (to the extent disallowed or to the extent made by mistake of fact) to the Employer upon the Employers written direction. In
making returns of contributions upon the Employers direction, the Trustee may accept such direction as the Employers warranty that such payment is provided for in the Plan and complies with both the provisions of the Plan and with the
provisions of this paragraph, and the Trustee need make no further investigation.



16. Law Governing. This agreement shall be administered, construed and enforced according to the laws of Connecticut and applicable Federal law.



17. Exclusive Benefit of Participants. Except in the case of a Qualified Domestic Relations Order as defined in
Section 414(p) of the Internal Revenue Code of 1986, as amended, it shall be impossible at any time prior to the satisfaction of all liabilities to the Participants for any part of the Fund, other than such part as is required to pay taxes,
administrative expenses or refund contributions as provided elsewhere herein, to be used for, or diverted to, purposes other than the exclusive benefit of the Participants.



18. Non-alienation of Benefits. Except in the case of a Qualified Domestic Relations Order as defined in Section
414(p) of the Internal Revenue Code of 1986, as amended, no rights or claims to any of the monies or other assets of the Fund shall be assignable, nor shall such rights or claims be subject to garnishment, attachment, execution or levy of any kind;
and any attempt to transfer, assign or pledge the same shall not be recognized by the Trustee.



19. Distribution. Notwithstanding any other provisions of this Agreement, the Trustee may condition its delivery, transfer or distribution of any assets upon the Trustees receiving assurances satisfactory
to it that the approval of appropriate governmental or other authorities has been secured and that all notice and other procedures required by applicable law have been complied with.



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20. Trustee not Liable for Duties not Assigned Herein. The duties of the Trustee to the Plan are
limited to those assumed by the Trustee by the terms of this Agreement. The Trustee shall not be deemed by virtue hereof to be the Administrator or Sponsor of the Plan, and shall not be responsible for filing reports, returns or disclosures with any
government agency except as may be required of the Trustee under applicable law or regulation.



21. Separability. If any provision of this Agreement is found, held or deemed to be void, unlawful or unenforceable under any applicable statute or other controlling law, the remainder of this Agreement shall
continue in full force and effect.



22. Dealing with the
Trustee. No person dealing with the Trustee will be obliged to see to the application of any property paid or delivered to the Trustee or to inquire into the expediency or propriety of any transaction or the Trustees authority to
consummate the same, except as may specifically be required of such person under ERISA.



23. Payment by Mail. If any check in payment of a benefit hereunder, which had been mailed by regular U.S. mail to the last address of the payee is returned undelivered, the Trustee shall so notify the Employer
and shall discontinue further payments to such payee until it receives further instructions from the Employer. The Trustee shall have no duty to locate participants.



24. Appointment of Separate Trustees. If at any time the Employer appoints two or more separate trustees to act
hereunder, the Employer shall direct the portion of the Fund and the accounts, books, and records relating thereto which each trustee shall hold, and the Employer shall direct the specific assets constituting the portion of the Fund to be
transferred from one of said trustees to another. If such a direction is given, each trustee shall individually invest and keep invested the portion of the Fund held by or from time to time paid over to it, all upon the conditions set forth in this
Agreement, as amended, as though the Employer had entered into a separate trust agreement with each trustee having the same terms as this Agreement, and each trustee shall be subject to the same duties and responsibilities and shall have the same
powers and rights for the portion of the Fund held by it as a single trustee would have for the entire Fund, and each trustee shall have no duties or responsibilities and shall have no powers or rights for the portion of the Fund held by another
such trustee. The Employer shall be responsible for overall diversification of the Fund. The Employer shall be responsible for overall compliance of the Fund with statutory limitations on the amount of investment in securities or property of the
Employer or any associated, affiliated or subsidiary company.



25. Signature Authority and Conformity with Plan. The person executing this agreement on behalf of the Employer certifies thereby that he or she is duly authorized by the Employer consistent with the terms of the Plan to do so. The
Employer, by executing this Agreement, certifies that the Plan has been duly adopted, that the provisions hereof are consistent with the terms of the Plan, that all conditions and limitations in the Plan which would limit the actions of the Trustee
are expressly contained herein, and that the Employer will promptly notify the Trustee of any amendments made to the Plan.



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IN WITNESS WHEREOF, the parties hereto have caused the respective duly authorized officers to
execute this Agreement in duplicate and affix their corporate seals hereto this 18th day of March, 2004.



|                           |  |                   |  |                                 
|-------------------------- |  | ----------------- |  | --------------------------------
|ATTEST:                    |  | SPIRE CORPORATION
|                           |  |                  
|/s/ Michael W. ODougherty |  | By:               |  | /s/ Roger G. Little             
|Michael W. ODougherty     |  | Name:             |  | Roger G. Little                 
|Clerk                      |  | Title:            |  | President & CEO                 
|                           | 
|                           |  | CORPORATE SEAL   
|                           | 
|ATTEST:                    |  | RIGGS BANK N.A.  
|                           |  |                  
|/s/ Olivia Duran           |  | By:               |  | /s/ Larry D. Harris             
|Olivia Duran               |  | Name:             |  | Larry D. Harris                 
|                           |  | Title:            |  | Vice President and Trust Officer
|                           | 
|                           |  | CORPORATE SEAL