SEC FORM 4

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

STEAG ELECTRONIC SYSTEMS AG

(Last)

(First)

(Middle)

RUETTENSCHEIDER STRASSE 1-3

(Street)

ESSEN

45128

(City)

(State)

(Zip)

2. Issuer Name and Ticker or Trading Symbol
MATTSON TECHNOLOGY INC [ MTSN ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

Director	X	10% Owner
Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
06/09/2005

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	06/09/2005		S		1,800,000	D	$7.5	7,061,144	D⁽¹⁾
Common Stock								135,574	I	By Limited Liability Company⁽²⁾

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

1. Name and Address of Reporting Person^*

STEAG ELECTRONIC SYSTEMS AG

(Last)

(First)

(Middle)

RUETTENSCHEIDER STRASSE 1-3

(Street)

ESSEN

45128

(City)

(State)

(Zip)

Relationship of Reporting Person(s) to Issuer

Director	X	10% Owner
Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

RAG AKTIENGESELLSCHAFT

(Last)

(First)

(Middle)

RELLINGHAUSER STRASSE 1-11

(Street)

ESSEN

D-45128

(City)

(State)

(Zip)

Relationship of Reporting Person(s) to Issuer

Director	X	10% Owner
Officer (give title below)		Other (specify below)

Explanation of Responses:

1. These shares are owned directly by STEAG Electronic Systems AG (SES), an indirect wholly owned subsidiary of RAG Aktiengesellschaft (RAG), and indirectly by RAG.

2. These shares represent the proportionate interest of SES and RAG in 271,147 shares of Mattson stock received by West STEAG Partners GmbH, a German limited liability corporation (WSP), pursuant to the terms of the acquisition of Vortek Industries Ltd., a corporation amalgamated under the laws of British Columbia, Canada by Mattson on October 27, 2004 (the Vortek Transaction). WSP is a venture capital firm, 50% of the capital of which is owned by SES. RAG and SES may be deemed to beneficially own the shares of Mattson Stock acquired by WSP in the Vortek Transaction based on SES's ownership of 50% of the capital of WSP. WSP does not act, and has no agreement with SES or RAG to act, together with SES and/or RAG for the purpose of acquiring, holding, voting or disposing of Mattson Stock. Accordingly, WSP does not beneficially own any of the shares of Mattson Stock beneficially owned by SES and RAG other than the 271,147 shares of Mattson Stock that WSP received in the Vortek Transaction.

Remarks:

	STEAG Electronic Systems AG, By: /s/ Wilhelm Pueschel, Member of the Board; By: /s/ Werner Beden, Member of the Board	06/10/2005
	RAG Aktiengesellschaft, By: /s/ Ulrich Weber, Member of the Board; By: /s/ Christoph Mueller, Senior Vice President	06/10/2005
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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