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                                                                     Exhibit 4.1

                                THERMA-WAVE, INC.
                          REGISTRATION RIGHTS AGREEMENT

     This Registration Rights Agreement ("Agreement") is made as of
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________________, 2002, between Therma-Wave, Inc., a Delaware corporation (the
"Buyer"), and shareholders of Sensys Instruments Corporation (the "Company
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Shareholders") listed on Exhibit A hereto [attach complete Sensys shareholder
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list; each Sensys shareholder must execute this Agreement to have such
shareholder's Buyer Shares registered], pursuant to that certain Agreement and
Plan of Reorganization by and among the Buyer, Sensys Instruments Corporation, a
California corporation (the "Company"), and certain other parties dated as of
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December 17, 2001 (the "Reorganization Agreement").
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     1.   Definitions. As used in this Agreement:
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          (a)  "Effective Time" means the "Effective Time" as defined in Section
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2(d)(i) of the Reorganization Agreement.

          (b)  "Form S-3" means such form under the Securities Act as in effect
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on the date hereof or any registration form under the Securities Act
subsequently adopted by the SEC which similarly permits inclusion or
incorporation of substantial information by reference to other documents filed
by the Buyer with the SEC.

          (c)  "Registrable Securities" means the Buyer Shares (i) issued to the
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Company Shareholders pursuant to the Reorganization Agreement and (ii) issuable
with respect to those assumed Company Stock Options and Stock Rights ineligible
to be registered on Form S-8 (or any successor form) pursuant to Section 6(g) of
the Reorganization Agreement; provided, however, that Registrable Securities
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shall not include (A) any Buyer Shares that have been previously sold to the
public or (B) any Buyer Shares that may be sold in the public market by a
Company Shareholder pursuant to Rule 144 under the Securities Act in a single
three (3) month period.

          (d)  "SEC" means the Securities and Exchange Commission.
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          (e)  "Securities Act" means the Securities Act of 1933, as amended,
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and the rules and regulations promulgated thereunder.

          Terms not otherwise defined herein have the meanings given to them in
the Reorganization Agreement.

     2.   Form S-3 Registration. The Buyer shall prepare and file with the
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SEC as soon as practicable after the Effective Time but in no event more than 60
days thereafter, and use its reasonable best efforts to have declared effective
by the SEC within 120 days of the Effective Time and maintain such effectiveness
for a period of one (1) year thereafter (the "Effectiveness Period"), a
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Registration Statement on Form S-3 providing for the resale by the Company
Shareholders of all Registrable Securities then owned by the Company
Shareholders; provided, however, that the Company Shareholders shall provide all
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such information and materials relating to the Company Shareholders, as
reasonably requested, and take all such action as may be reasonably required in
order to permit the Buyer to comply with all the applicable

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requirements of the SEC and to obtain any desired acceleration of the effective
date of such Form S-3, such provision of information and materials to be a
condition precedent to the obligations of the Buyer to file such Registration
Statement pursuant to this Agreement and the Reorganization Agreement. The
offering made pursuant to such registration shall not be underwritten.

     3.   Postponement of Registration. If the Buyer shall determine, pursuant
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to the good faith judgment of its Board of Directors, that there is (a) a
material development or potential material development with respect to or
involving the Buyer which the Buyer would be obligated to disclose in the
prospectus included in the registration statement filed pursuant to Section 2
hereof or any document incorporated or deemed to be incorporated therein by
reference, which disclosure would in the good faith judgment of the Board of
Directors of the Buyer be premature or inadvisable at such time, or (b) the
occurrence of any event that makes any statement made in the registration
statement or prospectus included in the registration statement filed pursuant to
Section 2 hereof or any document incorporated or deemed to be incorporated
therein by reference untrue in any material respect, or which requires the
making of any changes in such registration statement or prospectus so that it
will not contain an untrue statement of material fact required to be stated
therein or necessary to make the statements therein, in light of the
circumstances in which they were made, not misleading, then the Buyer shall
notify the Company Shareholders in writing of the foregoing, and upon receipt of
such notice, the use of such registration statement and prospectus shall be
deferred or suspended and will not recommence until (i) the Company Shareholders
receive from the Buyer copies of a supplemented or amended prospectus, or (ii)
such Company Shareholders are advised in writing by the Buyer that the
prospectus may be used. The Buyer will use its reasonable efforts to (A)
supplement or amend the registration statement or prospectus filed pursuant to
Section 2 hereof, to the extent necessary due to the occurrence of any event
described in clause (b) above, and (B) allow use of the prospectus to resume
expeditiously; provided that the Buyer shall be under no obligation to take any
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action or make any disclosure which would be detrimental to the Buyer or its
stockholders in the good faith judgment of the Board, including without
limitation disclosure of any pending business transactions or negotiations. To
the extent the use of such registration statement and prospectus is deferred or
suspended pursuant to this Section 3, the Effectiveness Period shall be extended
by the period of any such deferral(s) or suspension(s).

     4.   Obligations of the Buyer. Except as set forth in Sections 2 and 3,
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whenever required to effect the registration of any Registrable Securities, the
Buyer shall (a) prepare and file with the SEC a registration statement, which
registration statement (including any amendments or supplements thereto and
prospectuses contained therein) shall not contain any untrue statement of
material fact or omit to state a material fact required to be stated therein, or
necessary to make the statements therein, in light of the circumstances in which
they were made, not misleading, (b) prepare and file with the SEC such
amendments and supplements to such registration statement as may be necessary to
comply with the provisions of the Securities Act, (c) furnish to the Company
Shareholders such number of copies of any prospectus (including any preliminary
prospectus and any amended or supplemented prospectus) as the Company
Shareholders may reasonably request in order to effect the offering and sale of
the shares of the Registrable Securities to be offered and sold, but only while
the Buyer shall be required under the provisions hereof to cause such
registration statement to remain current; (d) use its commercially reasonable
efforts to register or qualify the shares of the Registrable Securities

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covered by such registration statement under the securities or blue sky laws of
such jurisdictions as the Company Shareholders shall reasonably request
(provided that the Buyer shall not be required in connection therewith or as a
condition thereto to qualify to do business or to file a general consent to
service of process in any such jurisdiction where it has not been qualified),
and do any and all other acts or things which may be reasonably necessary or
advisable to enable the Company Shareholders to consummate the public sale or
other disposition of the Registrable Securities in such jurisdictions; (e) cause
all such Registrable Securities to be listed on each securities exchange or
National Association of Securities Dealers, Inc. Automated Quotation System on
which similar securities issued by the Buyer are then listed; (f) so long as the
registration statement remains effective, promptly prepare, file and furnish to
the Company Shareholders a reasonable number of copies of any supplements to or
amendments of such prospectus; (g) notify the Company Shareholders promptly of
any request by the SEC for the amending or supplementing of such registration
statement or prospectus or for additional information; and (h) advise the
Company Shareholders promptly after it shall receive notice or obtain knowledge
thereof, of the issuance of any stop order by the SEC suspending the
effectiveness of any registration statement or the initiation or threatening of
any proceeding for that purpose and promptly use commercially reasonable efforts
to prevent the issuance of any stop order or to obtain its withdrawal if such
stop order should be issued.

     5.   Expenses. The Buyer shall pay the expenses incurred by the Buyer in
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connection with any registration of Registrable Securities pursuant to this
Agreement including all SEC, NASD and blue sky registration and filing fees,
printing expenses, transfer agents' and registrars' fees, and the fees and
disbursements of the Buyer's outside counsel and independent auditors. In
connection with the Registration Statement on Form S-3 pursuant to this
Agreement, the Buyer shall pay the reasonable fees and disbursements of not more
than one (1) counsel chosen by the holders of a majority of the Registrable
Securities covered thereby to act as counsel for such holders in connection
therewith. The Company Shareholders shall be responsible for all broker
discounts and commissions and transfer taxes, as well as any other expenses
incurred by the Company Shareholders.

     6.   Indemnification. In the event of any offering registered pursuant to
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this Agreement:

          (a)  The Buyer will indemnify each Company Shareholder (and to the
extent such Company Shareholder is not a natural person, each of its directors
and officers and each person who controls such Company Shareholder within the
meaning of Section 15 of the Securities Act) with respect to any registration
effected pursuant to this Agreement, against all expenses, claims, losses,
damages and liabilities (or actions in respect thereof), including any of the
foregoing incurred in settlement of any litigation, commenced or threatened,
arising out of or based on any untrue statement (or alleged untrue statement) of
a material fact contained in any registration statement, or any amendment or
supplement thereto, or prospectus related thereto, incident to any such
registration, or based on any omission (or alleged omission) to state therein a
material fact required to be stated therein or necessary to make the statements
therein, in light of the circumstances in which they are made, not misleading,
or any violation by the Buyer of the Securities Act, in connection with any such
registration, and will reimburse such Company Shareholder, for any legal and any
other expenses reasonably incurred in connection with investigating, preparing
or defending any such claim, loss, damage, liability or action, provided

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that the Buyer will not be liable in any such case (i) to the extent that any
such claim, loss, damage, liability or expense arises out of or is based in any
untrue statement or omission or alleged untrue statement or omission, made in
reliance upon and in conformity with information furnished to the Buyer by such
Company Shareholder or (ii) if a copy of the final prospectus relating to any
registration statement (as then amended or supplemented if the Buyer shall have
furnished any amendments or supplements thereto) (the "Final Prospectus") was
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not sent or given by or on behalf of such Company Shareholder to a purchaser of
the Company Shareholder's Registrable Securities, if required by law so to have
been delivered, at or prior to the written confirmation of the sale of the
Registrable Securities to such purchase, and if the final prospectus (as so
amended or supplemented) would have cured the defect giving rise to such loss,
claim, damage or liability.

          (b)  Each Company Shareholder will severally indemnify the Buyer, each
of its directors and officers, and each person who controls the Buyer within the
meaning of Section 15 of the Securities Act, against all claims, losses, damages
and liabilities (or actions in respect thereof) arising out of or based on any
untrue statement (or alleged untrue statement) or a material fact contained in
any registration statement, or any amendment or supplement thereto, or
prospectus related thereto, or any omission (or alleged omission) to state
therein a material fact required to be stated therein or necessary to make the
statements therein not misleading, but only to the extent, that such untrue
statement (or alleged untrue statement) or omission (or alleged omission) is
made in such registration statement or prospectus in reliance upon and in
conformity with information furnished to the Buyer by such Company Shareholder
and will reimburse the Buyer, the remaining Company Shareholders, such
directors, officers, or control persons for any legal or any other expenses
reasonably incurred in connection with investigating or defending any such
claim, loss, damage, liability or action.

          (c)  Each party entitled to indemnification under this Section 6 (the
"Indemnified Party") shall give notice to the party required to provide
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indemnification (the "Indemnifying Party") promptly after such Indemnified Party
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has notice of any claim as to which indemnity may be sought, and shall permit
the Indemnifying Party to assume the defense of any such claim or any litigation
resulting therefrom, and the Indemnified Party may participate in such defense
at such party's expense, and provided further that the failure of any
Indemnified Party to give notice as provided herein shall not relieve the
Indemnifying Party of its obligations under this Agreement, except to the
extent, but only to the extent, that the Indemnifying Party's ability to defend
against such claim or litigation is impaired as a result of such failure to give
notice. No Indemnifying Party, in the defense of any such claim or litigation,
shall, except with the consent of each Indemnified Party, consent to entry of
any judgment or enter any settlement which does not include as an unconditional
term thereof the giving by the claimant or plaintiff to such Indemnified Party
of a release from all liability in respect to such claim or litigation. Whether
or not the defense of any claim or action is assumed by the Indemnifying Party,
such Indemnifying Party will not be subject to any liability for any settlement
without its consent, which shall not be unreasonably withheld.

          (d)  The obligations of the Buyer and the Company Shareholders under
this Section 6 shall survive the completion of any offering of stock in a
registration statement under this Agreement.

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     7.   Assignment of Registration Rights. The rights to cause the Buyer to
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register Registrable Securities pursuant to this Agreement may be assigned by
the Company Shareholders only to: (a) a subsidiary, parent or affiliate of a
Company Shareholder which is a corporation, (b) as a distribution made by a
Company Shareholder which is a partnership, limited liability company or
corporation to its partners, members and stockholders, as the case may be, in
accordance with their interest in such entity, or (c) by a Company Shareholder
which is an individual to a member of the Company Shareholder's immediate family
or a trust established for the benefit of the Company Shareholder or members of
its immediate family; provided, however, that upon the death of any Company
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Shareholder which is an individual, the rights to cause the Buyer to register
Registrable Securities pursuant to this Agreement shall inure to such Company
Shareholder's devisee, legatee or other designee.

     8.   Amendment of Registration Rights. This Agreement may be amended by the
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holders of a majority of the Registrable Securities and the Buyer at any time by
execution of an instrument in writing signed on behalf of each of its parties.

     9.   Grant of Additional Registration Rights. The Company Shareholders
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acknowledge that the Buyer may acquire other companies, businesses or assets and
in the course of such acquisitions may grant the equity owners thereof
registration rights with respect to their shares of the Buyer on terms which
would be negotiated at such time and may be materially different than the terms
of this Agreement.

     10.  Notices. All notices and other communications hereunder shall be in
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writing and shall be deemed given if delivered personally or by commercial
messenger or courier service, or mailed by registered or certified mail (return
receipt requested) or sent via facsimile (with acknowledgement of complete
transmission) to the parties, addressed (a) if to the Company Shareholders, at
the Company Shareholders' addresses as set forth in the securities register of
the Buyer or (b) if to the Buyer, at 1250 Reliance Way, Fremont, California
94539, Attention: Martin M. Schwartz.

     11.  Governing Law; Interpretation. This Agreement shall be construed in
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accordance and governed for all purposes by the laws of the State of California
regardless of the laws that might otherwise govern under applicable principles
of conflicts of laws thereof.

     12.  Severability; Survival. If any portion of this Agreement is held by a
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court of competent jurisdiction to conflict with any federal, state or local
law, or to be otherwise invalid or unenforceable, such portion of this Agreement
shall be of no force or effect, and this Agreement shall otherwise remain in
full force and effect and be construed as if such portion had not been included
in this Agreement.

     13.  Entire Agreement. This Agreement contains the entire agreement and
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understanding of the parties and supersedes all prior discussions, agreement and
understandings relating to the subject matter hereof.

     14.  Counterparts. This Agreement may be executed in one or more
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counterparts, all of which shall be considered one and the same agreement and
shall become effective when one

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or more counterparts have been signed by each of the parties and delivered to
the other party, it being understood that all parties need not sign the same
counterpart.

     15.  Current Public Information. The Buyer shall use its reasonable efforts
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to file all reports required to be filed by it for Company Shareholders to be
eligible to sell Buyer Shares pursuant to Rule 144 under the Securities Act.

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     IN WITNESS WHEREOF, the Buyer and the Company Shareholders have caused this
Agreement to be executed as of the date first above written.


                                     THERMA-WAVE, INC.

                                     By:
                                         ---------------------------------------
                                         Name:
                                         Title:

                                     COMPANY SHAREHOLDERS1

                                     By:
                                         ---------------------------------------
                                         Name:
                                         Title:



                                     -------------------------------------------
                                     Print Name of Company Shareholder




                [SIGNATURE PAGE TO REGISTRATION RIGHTS AGREEMENT]



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1    Spousal consents required for individual Company Shareholders.