<PAGE>

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

                            ------------------------

                                  FORM 10-Q/A
                               AMENDMENT NO. 1 TO

(Mark One)

[X]   QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES 
      EXCHANGE ACT OF 1934
For the quarterly period ended September 27, 1998

                                       OR

[ ]   TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES 
      EXCHANGE ACT OF 1934

For the transition period from                       to
                               ---------------------    ---------------------

Commission file number 0-21970

                            ------------------------

                            MATTSON TECHNOLOGY, INC.
             (Exact name of registrant as specified in its charter)

DELAWARE                                           77-0208119
(State or other jurisdiction of         (I.R.S. Employer Identification No.)
incorporation or organization)

3550 WEST WARREN AVENUE
FREMONT, CALIFORNIA                                  94538
(Address of principal executive offices)          (Zip Code)

                                 (510) 657-5900
              (Registrant's telephone number, including area code)

                            ------------------------

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days.
                          Yes  X      No    
                              ---        ---

Number of shares of common stock outstanding as of November 6, 1998: 15,001,191

                                       1

<PAGE>

The undersigned registrant hereby amends the following items, financial 
statements and exhibits or other portions of its Quarterly Report on Form 
10-Q filed November 12, 1998 as set forth in the pages attached hereto.

                        PART I -- FINANCIAL INFORMATION

ITEM 1.   FINANCIAL STATEMENTS

                           MATTSON TECHNOLOGY, INC.
                      CONDENSED CONSOLIDATED BALANCE SHEET
                                (in thousands)
                                 (unaudited)

<TABLE>
<CAPTION>

                                   ASSETS

                                                        SEPT. 27,     DEC. 31,
                                                          1998          1997
                                                          ----          ----
<S>                                                     <C>          <C>
Current assets:
    Cash and cash equivalents                           $  21,716    $  25,583
    Short-term investments                                  7,170        8,598
    Accounts receivable, net                                9,246       14,784
    Inventories                                            11,738       19,068
    Income tax receivable                                   3,300            -
    Notes receivable from stockholder                       3,129            -
    Deferred taxes                                              -        4,222
    Prepaid expenses and other current assets               1,510        1,000
                                                        ---------    ---------
      Total current assets                                 57,809       73,255
Property and equipment, net                                12,950       11,188
Other assets                                                5,616            -
                                                        ---------    ---------
                                                        $  76,375    $  84,443
                                                        ---------    ---------
                                                        ---------    ---------

                   LIABILITIES AND STOCKHOLDERS' EQUITY

Current liabilities:
    Accounts payable                                    $   4,637    $   3,349
    Accrued liabilities                                    19,044       12,910
                                                        ---------    ---------
      Total current liabilities                            23,681       16,259
                                                        ---------    ---------

Stockholders' equity:
    Common stock                                               15           14
    Additional paid in capital                             62,521       57,418
    Retained earnings                                      (6,629)      12,117
    Treasury stock                                         (2,987)      (1,075)
    Other                                                    (226)        (290)
                                                        ---------    ---------
                                                        ---------    ---------
      Total stockholders' equity                           52,694       68,184
                                                        ---------    ---------
                                                        ---------    ---------
                                                        $  76,375    $  84,443
                                                        ---------    ---------
                                                        ---------    ---------
</TABLE>

    See accompanying notes to condensed consolidated financial statements.

                                       2

<PAGE>
                            MATTSON TECHNOLOGY, INC.
                 CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS
                    (in thousands, except per share amounts)
                                 (unaudited)

<TABLE>
<CAPTION>

                                                                          THREE MONTHS ENDED           NINE MONTHS ENDED
                                                                          ------------------           -----------------
                                                                       SEPT. 27,      SEPT. 28,     SEPT. 27,      SEPT. 28,
                                                                         1998           1997          1998           1997
                                                                         ----           ----          ----           ----
<S>                                                                   <C>            <C>           <C>            <C>
Net sales                                                             $    9,420     $   22,633    $    45,317    $    52,227
Cost of sales                                                              8,924         10,784         28,545         25,507
                                                                      ----------     ----------    -----------    -----------
  Gross profit                                                               496         11,849         16,772         26,720
                                                                      ----------     ----------    -----------    -----------
Operating expenses:
  Research, development and engineering                                    4,107          3,899         12,379         10,076
  Selling, general and administrative                                      6,240          6,884         18,607         17,193
  Acquired in-process research and development                             5,750              -          5,750              -
                                                                      ----------     ----------    -----------    -----------
    Total operating expenses                                              16,097         10,783         36,736         27,269
                                                                      ----------     ----------    -----------    -----------
Income (loss) from operations                                            (15,601)         1,066        (19,964)          (549)
Interest and other income (expense), net                                     431            351          1,420          1,198
                                                                      ----------     ----------    -----------    -----------
Income (loss) before income taxes                                        (15,170)         1,417        (18,544)           649
Provision for (benefit from) income taxes                                  1,109            468            200            213
                                                                      ----------     ----------    -----------    -----------
Net income (loss)                                                     $  (16,279)    $      949    $   (18,744)   $       436
                                                                      ----------     ----------    -----------    -----------
                                                                      ----------     ----------    -----------    -----------

Net income (loss) per share:
  Basic                                                               $    (1.10)    $     0.07    $     (1.29)   $      0.03
                                                                      ----------     ----------    -----------    -----------
                                                                      ----------     ----------    -----------    -----------
  Diluted                                                             $    (1.10)    $     0.06    $     (1.29)   $      0.03
                                                                      ----------     ----------    -----------    -----------
                                                                      ----------     ----------    -----------    -----------


Weighted average shares outstanding:
  Basic                                                                   14,839         14,109         14,522         14,103
                                                                      ----------     ----------    -----------    -----------
                                                                      ----------     ----------    -----------    -----------
  Diluted                                                                 14,839         15,629         14,522         15,286
                                                                      ----------     ----------    -----------    -----------
                                                                      ----------     ----------    -----------    -----------
</TABLE>

    See accompanying notes to condensed consolidated financial statements.

                                       3

<PAGE>

                            MATTSON TECHNOLOGY, INC.
                 CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS
                                 (in thousands)
                                   (unaudited)
<TABLE>
<CAPTION>

                                                                      NINE MONTHS ENDED
                                                                      -----------------
                                                                  SEPT.  27,     SEPT.  28,
                                                                     1998           1997
                                                                     ----           ----

<S>                                                              <C>             <C>
Cash flows from operating activities:
    Net income (loss)                                            $  (18,744)     $     436
    Adjustments to reconcile net income  to 
      net cash used in operating activities:
      Depreciation                                                    2,517          2,104
      In-process research and development                             5,750              -
      Amortization of intangibles                                       288              -
Changes in assets and liabilities:
      Accounts receivable                                             5,877           (452)
      Inventories                                                     9,900         (5,215)
      Income tax receivable                                          (2,778)             -
      Deferred taxes                                                  4,222              -
      Prepaid expenses and other assets                                (391)          (540)
      Accounts payable                                               (3,230)         1,939
      Accrued liabilities                                            (2,919)         1,167
                                                                 ----------      ---------
      Net cash provided by (used in) operating activities               492           (561)
                                                                 ----------      ---------
Cash flows from investing activities:
    Acquisition of property and equipment                            (1,224)        (2,070)
    Notes receivable shareholder                                     (3,129)
    Purchases of short-term investments                             (40,676)       (14,036)
    Sales and maturities of short-term investments                   42,126         22,024
                                                                 ----------      ---------
      Net cash provided by (used in) investing activities            (2,903)         5,918
                                                                 ----------      ---------
Cash flows from financing activities:
    Proceeds from the issuance of Common Stock, net                     413            978
    Purchase of Common Stock                                         (1,912)        (3,131)
                                                                 ----------      ---------
      Net cash used in financing activities                          (1,499)        (2,153)
                                                                 ----------      ---------
Effect of exchange rate changes on cash and cash equivalents             43            (59)
                                                                 ----------      ---------
Net increase (decrease) in cash and cash equivalents                 (3,867)         3,145
Cash and cash equivalents, beginning of period                       25,583         21,547
                                                                 ----------      ---------
Cash and cash equivalents, end of period                         $   21,716      $  24,692
                                                                 ----------      ---------
                                                                 ----------      ---------
</TABLE>

     See accompanying notes to condensed consolidated financial statements.

                                       4

<PAGE>

                            MATTSON TECHNOLOGY, INC.
              NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS
                                   (UNAUDITED)

NOTE 1  BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

BASIS OF PRESENTATION

The accompanying unaudited condensed consolidated financial statements have been
prepared in accordance with generally accepted accounting principles for interim
financial information and with the instructions to Form 10-Q and Regulation S-X.
Accordingly, they do not include all of the information and footnotes required
by generally accepted accounting principles for complete financial statements. 
In the opinion of management, all adjustments (consisting of normal recurring
adjustments) considered necessary for a fair presentation  have been included.

The financial statements should be read in conjunction with the audited
financial statements included in the Company's Annual Report for the year ended
December 31, 1997.

The results of operations for the three month and nine month periods ended
September 27, 1998 are not necessarily indicative of results that may be
expected for the entire year ending December 31, 1998.

NOTE 2  ACQUISITION OF CONCEPT SYSTEMS DESIGN

On July 24, 1998, the Company completed its acquisition of Concept. The 
transaction was achieved through the merger of a wholly-owned subsidiary of 
the Company with and into Concept. In connection with the merger, the Company 
issued 795,138 shares of Common Stock to the former shareholders of Concept.  
The former shareholders of Concept also may acquire up to 547,569 additional 
shares of the Company's Common Stock in connection with the merger if certain 
conditions are met prior to the end of the first twenty-four full calendar 
months following the closing of the transaction. The merger has been 
accounted for as a purchase.  The purchase price of the acquisition of 
$4,689,000, which includes $650,000 of estimated acquisition related costs, 
was used to acquire the net assets of Concept. The purchase price was 
allocated to assets acquired and liabilities assumed based on the book value 
of Concept's current assets and liabilities, which management believes 
approximates their fair value, the estimated fair value of property and 
equipment, based on management's estimates of fair value, and an independent 
appraisal for all other identifiable assets.  The excess of the purchase 
price over the net tangible and intangible assets acquired and liabilities 
assumed has been allocated to goodwill.  The allocation of the purchase price 
was as follows (in thousands):

<TABLE>
     <S>                                             <C> 
     Property and equipment                          $  3,055
     Current and other assets                           4,041
     Liabilities assumed                              (13,570)
     Goodwill                                              36
     Acquired in-process research and development       5,750
     Acquired developed technology and workforce        5,377
                                                     --------  
                                                     $  4,689
                                                     --------
                                                     --------
</TABLE>


The acquired in-process technology research and development was expensed  the 
quarter ended September 27, 1998.  The acquired developed technology, 
workforce and goodwill will be amortized to income over periods ranging from 
3 to 7 years.

In addition to the purchase price shown above, the agreement for the 
acquisition of Concept also includes the contingent distribution of shares of 
Common Stock of Mattson of 100,000 shares that will be issued to the Concept 
shareholders if Concept achieves net revenues of at least $16,667,000 during 
the first twenty-four full calendar months following the acquisition date.  
Up to an additional 447,569 shares of Mattson Common Stock will be issued to 
the Concept shareholders if the net revenue milestone is achieved and the 
stock price of Mattson Common Stock does not reach at least $12 per share for 
any consecutive ten day trading period during the twenty-four full calendar 
months following the acquisition.

The following table represents pro forma information assuming that the 
acquisition took place at the beginning of the periods presented.


<TABLE>
<CAPTION>

     (In thousands)          Unaudited           Unaudited
                           9 Months ended      12 Months ended 
                         September 27, 1998    December 31, 1997
                         ------------------    -----------------
     <S>                 <C>                   <C> 
     Operating revenue     $         48,558      $        83,040
     Net loss                       (28,149)              (8,398)
     Basic and diluted 
      loss per share                  (1.90)               (0.56)

</TABLE>

NOTE 3 NOTES RECEIVABLE FROM STOCKHOLDER

During the third quarter of 1998 the Company extended a one year loan to Brad 
Mattson, the Chief Executive Officer of the Company, in the amount of $3.1 
million.  The loan is collateralized by 2.2 million shares of the Company's 
Common Stock and is a full recourse note bearing interest at the market rate. 
 Interest is payable at the end of the one year loan.

NOTE 4  BALANCE SHEET DETAIL (IN THOUSANDS):

<TABLE>
<CAPTION>

                                                   SEPT. 27,       DEC. 31,
                                                     1998            1997
                                                     ----            ----

<S>                                                <C>            <C>
Inventories:
    Purchased parts and raw materials              $   7,532      $   7,648
    Work-in-process                                    3,465          7,606
    Finished goods                                       376          2,266
    Evaluation systems                                   365          1,548
                                                   ---------      ---------
                                                   $  11,738      $  19,068
                                                   ---------      ---------
                                                   ---------      ---------

Accrued liabilities:
    Warranty, installation and retrofit reserve    $   5,426      $   4,756
    Accrued compensation and benefits                  1,574          2,199
    Income taxes                                       1,263          1,971
    Commissions                                          553          1,277
    Deferred income                                    4,353          1,598
    Customer deposits                                  2,801              -
    Facilities consolidation accrual                   3,074              -
    Other                                                  -          1,109
                                                   ---------      ---------
                                                   $  19,044      $  12,910
                                                   ---------      ---------
                                                   ---------      ---------
</TABLE>

NOTE 5  CERTAIN STOCK TRANSACTIONS

In March 1998, the Company announced that its Board of Directors had authorized
the Company to repurchase during the next three years up to 1,000,000 shares of
the Company's Common Stock in the open market from time to time. As of November
3, 1998, the Company had repurchased 274,800 shares for approximately $1.9
million.  

                                       5

<PAGE>

NOTE 6  NEW ACCOUNTING PRONOUNCEMENT

As of January 1, 1998, the Company adopted Statement of Financial Accounting
Standards No. 130 (SFAS 130), "Reporting Comprehensive Income".  SFAS 130
establishes new rules for the reporting and display of comprehensive income and
its components; however, the adoption of this Statement had no impact on the
Company's net income or stockholders' equity.  SFAS 130 requires unrealized
gains or losses on the Company's available for sale securities and foreign
currency translation adjustments, which prior to  adoption were reported
separately in stockholders' equity, to be included in other comprehensive
income.  Prior year financial statements have been reclassified to conform to
the requirements of SFAS 130.

 .

The following are the components of comprehensive income (loss):

<TABLE>
<CAPTION>

                                                  THREE MONTHS ENDED            NINE MONTHS ENDED
(in thousands)                                SEPT. 27,        SEPT. 28,    SEPT. 27,        SEPT. 28,
                                                 1998            1997         1998             1997
                                                 ----            ----         ----             ----

<S>                                          <C>                <C>        <C>                <C>
Net income (loss)                            $  (16,279)        $  949     $  (18,742)        $  436
Foreign currency translation adjustments             36            (12)            64            (69)
                                             ----------         ------     ----------         ------

Comprehensive income (loss)                  $  (16,243)        $  937     $  (18,678)        $  367
                                             ----------         ------     ----------         ------
                                             ----------         ------     ----------         ------
</TABLE>

NOTE 7 NET INCOME (LOSS) PER SHARE

The Company adopted Financial Accounting Standards Board (FASB) Statement 128 
effective with the quarter and year ended December 31, 1997. All earnings per 
share data has been restated to reflect the FASB 128 method of computation. 
FASB 128 requires dual presentation of basic and diluted earnings per share 
(EPS) on the face of the income statement. Basic EPS is computed by dividing 
income available to common stockholders (numerator) by the weighted average 
number of common shares outstanding (denominator) for the period. Diluted EPS 
gives effect to all dilutive potential common shares outstanding during the 
period. The computation of diluted EPS uses the average market prices during 
the period. 

For the quarter and nine months ended September 27, 1998, there were no 
differences between the numerators and denominators used for the basic and 
diluted EPS calculations. For the quarter and nine months ended September 28, 
1997, there were no differences in the numerators used for the basic and 
diluted EPS calculations; however, there were differences in the denominators 
because of the effect of including dilutive stock options. Total stock 
options outstanding at September 27, 1998 were 2,696,461.

ITEM 2.   MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
RESULTS OF OPERATIONS.

OVERVIEW

Mattson Technology, Inc. ("Mattson" or  the "Company") designs, manufactures and
markets advanced fabrication equipment to semiconductor manufacturers worldwide.
The Company's product line is based on the Company's modular "Aspen" platform,
which accommodates two process chambers supporting increased throughput.  The
Company currently offers Aspen Strip, CVD, RTP, LiteEtch  based upon the Aspen
platform and now with the acquisition of Concept Systems Design ("Concept"), 
the Company also now offers Epi products. To date, the Company has derived a
substantial majority of its sales from Aspen Strip systems.  In addition, the
Company derives sales from spare parts and maintenance services.

                                       6

<PAGE>

The cyclicality and uncertainties regarding overall market conditions continue
to present significant challenges to the Company and may continue to have a
significant adverse impact on the Company's ability to forecast near term
revenue expectations.  The ability of the Company to modify its operations in
response to short term changes in market conditions is limited.  The extent and
duration of the continued reduction in capital spending in the semiconductor
industry and the ultimate impact on the Company and its results of operations
and financial condition cannot be precisely predicted.  

The Company continues to be affected by the continuing industry slowdown.  In
response to continued lower revenues, the Company has implemented and adhered to
its cost control measures, including a 15 percent reduction in its workforce and
a reduction in executive salaries. Future results will depend on a variety of
factors, particularly overall market conditions and also timing of significant
orders; the ability of the Company to bring new systems to market; the timing of
new product releases by the Company's competitors; patterns of capital spending
by the Company's customers; market acceptance of new and/or enhanced versions of
Company systems; changes in pricing by the Company, its competitors, customers,
or suppliers and the mix of products sold.

The Company generally recognizes a sale upon shipment of a system.  However,
from time to time, the Company allows customers to evaluate systems.  The
Company does not recognize the associated sale until and unless an evaluation
system is accepted by the customer.  

On July 24, 1998 the Company completed its acquisition of Concept Systems 
Design, Inc. ("Concept"), a supplier of epitaxial (EPI) systems. The 
transaction was achieved through the merger of a wholly owned subsidiary of 
Mattson with and into Concept. In connection with the merger, Mattson issued 
795,138 shares of Mattson Common Stock to the former shareholders of Concept. 
The former shareholders of Concept also may acquire up to 547,569 additional 
shares of Mattson Common Stock in connection with the merger if certain 
conditions are met prior to the end of the first twenty-four full calendar 
months following the closing of the transaction. The transaction has been 
accounted for as a purchase.  The acquisition resulted in a $5.8 million 
write-off of in-process research and development in the third quarter of 1998.

IMPACT OF YEAR 2000
Some of the Company's older computer programs were written using two digits
rather than four to define the applicable year.  As a result, those computer
programs have time-sensitive software that may recognize a date using "00" as
the year 1900 rather than the year 2000.  This could cause a system failure or
miscalculations causing disruptions of operations, including, among other
things, a temporary inability to process transactions, send invoices, or engage
in similar normal business activities.

The Company has commenced a Year 2000 date conversion project to address
necessary changes and an implementation strategy.  The "Year 2000 Computer
Problem" creates risks for the Company from unforeseen problems in its own
computer systems and from third parties with whom the Company deals on financial
transactions.  The Company does not anticipate that it will incur material
expenditures for the resolution of any Year 2000 issues related either to its
own information systems, databases and programs, or its products.  However,
there can be no assurance that the Company will not experience serious
unanticipated negative consequences or material costs caused by undetected
errors.  In addition, the Company could be adversely impacted by Year 2000
issues faced by major distributors, suppliers, customers, vendors and financial
service organizations with which the Company interacts.  Management is in the
process of determining the impact, if any, that third parties who are not Year
2000 compliant may have on the operations of the Company.

FORWARD LOOKING STATEMENTS

This report on Form 10-Q contains forward looking statements regarding, among
other matters, the Company's future strategy, product development plans, and
productivity gains and growth.  The forward looking statements are made pursuant
to the safe harbor provisions of the Private Securities Litigation Reform Act of
1995.  Forward looking statements address matters that are subject to a number
of risks and uncertainties.  In addition to the general risks associated with
the development of complex technology, future results of the Company will depend
on a variety of factors as described herein and in other filings made by the
Company with the Securities and Exchange Commission.

                                       7

<PAGE>

RESULTS OF OPERATIONS

The following table sets forth the statement of operations data of the Company
expressed as a percentage of net sales for the period indicated:

<TABLE>
<CAPTION>

                                                                 THREE MONTHS ENDED          NINE MONTHS ENDED
                                                                 ------------------          -----------------
                                                              SEPT. 27,     SEPT. 28,     SEPT. 27,     SEPT. 28,
                                                                1998          1997          1998          1997
                                                                ----          ----          ----          ----

<S>                                                           <C>           <C>           <C>           <C>
Net sales                                                       100%          100%          100%          100%
Cost of sales                                                    95%           48%           63%           49%
                                                                 ---           ---           ---           ---
    Gross margin                                                  5%           52%           37%           51%
                                                                  --           ---           ---           ---
Operating expenses:
    Research, development and engineering                        44%           17%           28%           19%
    Selling, general and administrative                          67%           30%           40%           33%
    Acquired in process research and development                 61%            -            13%            -
      Total operating expenses                                  172%           48%           81%           52%
Income (loss) from operations                                  (166)%           5%          (44%)          (1%)
Income (loss) before income taxes                              (161))%          6%          (41)%           1%
Net income (loss)                                              (173)%           4%          (42)%           1%
</TABLE>

NET SALES

Net sales for the third quarter of 1998 decreased 58% to $9.4 million from $22.6
million for the third quarter of 1997. The quarterly decrease in sales reflected
a 67% decrease in unit sales for the third quarter of 1998 compared to the third
quarter of 1997. There were no system revenues from the newly acquired Concept
Epi product line.   Net sales for the first nine months of 1998 decreased 13% to
$45.3 million from $52.2 million for the first nine months of 1997. Net sales
for the first nine months of 1998 compared to first nine months of 1997
reflected a 20% decrease in unit sales.  This decrease was due to the Company's
lower sales of its Aspen Strip products which was principally a result of the
general industry slowdown. 

Third quarter bookings were $11.0 million, down from $25.2 million for the 
third quarter of 1997, a decrease of 57 percent. Backlog decreased 46% to 
$21.9 million, compared to $40.2 million at the end of the third quarter of 
1997. There were no system bookings from the newly acquired Concept Epi 
product line and there is no current backlog. 

Average selling prices (ASP's) increased 6% for the third quarter of 1998 
compared to the third quarter of 1997. The increases were primarily as result 
of a sale of a dual chamber CVD partially offset by lower ASP's on the Aspen 
Strip single chamber.  ASP's increased 4% for the first nine months of 1998 
compared to the first nine months of 1997. The increases were primarily a 
result of the proportionate decrease in sales of the Aspen Strip single 
chamber systems.

International sales to customers based in Europe, Japan and the Pacific Rim
(which includes Taiwan, Singapore and Korea), accounted for 62% and 78% of net
sales for the third quarter of 1998 and 1997, respectively. International sales
for the first nine months of 1998 and 1997 were 72% and 56% of net sales,
respectively. All sales are denominated in U.S. dollars.  The Company's
operating results could be materially and adversely affected by any loss of
business from, the cancellation of orders by, or decreases in prices of systems
sold through Marubeni, the Company's distributor in Japan.  The Company
anticipates that international sales will continue to account for a significant
portion of 1998 total net sales.

                                       8

<PAGE>

GROSS MARGIN

The Company's gross margin for the third quarter of 1998 decreased to 5% from
52% for the third quarter of 1997, and for the first nine months of 1998
decreased to 37% from 51% for the first nine months of 1997. The decrease in
margins was significantly affected by a $2.6 million write down of inventory
related to the Company's 300mm program. Due to the continued push-out of the
industry 300mm requirements, previously inventoried 300mm program materials have
been expensed in the third quarter.  Also, the addition of Concept manufacturing
overhead, the lower production volumes and pricing pressure in Taiwan and Japan
continue to result in lower margins.

The Company's gross margin may continue to be affected by a variety of factors.
Although the Company has not offered substantial discounts on its systems to
date, there can be no assurance that the Company will not continue to experience
pricing pressures in the future.  The Company's gross margin on international
sales, other than sales through Marubeni, is substantially the same as domestic
sales.  Sales to Marubeni typically carry a lower gross margin, as Marubeni is
primarily responsible for sales and support costs in Japan.

The Company's reliance on outside vendors generally, and a sole or a limited
group of suppliers in particular, involves several risks, including a potential
inability to obtain an adequate supply of required components and reduced
control over pricing and timely delivery of components.  Any inability to obtain
adequate deliveries or any other circumstance that would require the Company to
seek alternative sources of supply or to manufacture such components internally
could delay the Company's ability to ship its systems and could have a material
adverse effect on the Company, including an increase in the Company's cost of
sales and therefore an adverse impact on gross margin.  In addition, new system
introductions and enhancements and rapid growth may also have an adverse effect
on gross margin due to the inefficiencies associated with manufacturing of new
product lines and rapid expansion, respectively.

RESEARCH, DEVELOPMENT AND ENGINEERING

Research, development and engineering expenses for the third quarter of 1998
were $4.1 million, or 44% of net  sales, as compared to $3.9 million, or 17%,
for the third quarter of 1997. The increase in expense as a percentage of net
sales for the third quarter of 1998 was due primarily to lower sales volume. The
addition of Concept increased research and development charges by approximately
$0.3 million for the third quarter of 1998.  Research, development and
engineering expenses for the first nine months of 1998 were $12.4 million, or
132% of net sales, as compared to $10.1 million, or 19%, for the first nine
months of 1997. The increase in expenses for the first nine months of 1998 as
compared to the first nine months of 1997 was primarily due to compensation
expense which increased to $6.4 million for the first nine months of 1998 from
$5.6 million for the first nine months of 1997 and engineering materials which
increased to $2.6 million for the first nine months of 1998 from $1.9 million
for the first nine months of 1997.  The Company believes that continued
investment in research and development, including its multi-product strategy is
critical to maintaining a strong technological position in the industry.

The loss in the third quarter of 1998 includes one-time charges of $5.7 million
for the write-down of certain in-process technology which were incurred as part
of the Company's acquisition of Concept Systems Design. 

SELLING, GENERAL AND ADMINISTRATIVE

Selling, general and administrative expenses for the third quarter of 1998 
were $6.2 million, or 67% of net sales, as compared to $6.9 million, or 30%, 
for the third quarter of 1997. The addition of Concept increased selling, 
general and administrative charges by approximately $0.5 million for the 
third quarter of 1998. The decrease in expenses for the third quarter of 1998 
was due to decreases in commission expense of $1.1 million partially offset 
by increases in building and utilities of $0.4 million and a $0.6 million non 
recurring facilities charge. The facilities charge relates to the remaining 
lease cost on the Company's former corporate offices which were vacated by a 
move of the corporate offices to the acquired Concept facilities.  The 
expenses for the nine months of 1998 were $18.6 million, or 41% of net sales, 
as compared to $17.2 million, or 32.9%, for nine months of 1997. The increase 
of $1.4 million in expenses for the nine months of 1998 was due to an 
increase in building and utilities of $0.9 million and the excess facilities 
charge of $0.6 million.

                                       9

<PAGE>

PROVISION FOR INCOME TAXES

The Company recorded an income tax expense of $1.1 million in the third 
quarter. This expense leaves the cumulative tax provision for the year at 
$0.2 million which relates to estimated foreign taxes.  The Company has 
recorded approximately $3.3 million in refundable taxes as a result of the 
current year losses which can be carried back to previous years taxes paid.  
In addition the Company has assessed the realizability of the remaining 
deferred tax assets and determined that a full valuation allowance is 
necessary for the deferred tax assets.

LIQUIDITY AND CAPITAL RESOURCES

Net cash used by operations during the first nine months of 1998 was $1.1
million, compared to $6.2 million of net cash used in operations during the
first nine months of 1997.  Net cash provided by operations during the first
nine months of  1998 was primarily attributable to  the net loss of $18.7
million partially offset by a decrease in accounts receivable of  $5.5 million,
a decrease in inventories of $7.3 million and an increase in accrued liabilities
of $6.1 million.

The Board of Directors has authorized the Company to repurchase up to 1,000,000
shares of the Company's Common Stock, of which 274,800 shares have been
repurchased by the Company as of November 3, 1998 for approximately $1.9
million.

During the third quarter of 1998 the Company extended a one year loan to Brad 
Mattson, the Chief Executive Officer of the Company, in the amount of $3.1 
million.  The loan is fully collateralized.  The interest rate established on 
the loan is set at the market rate.  The note is a full recourse note.

While the Company believes that it currently has sufficient cash and 
short-term investment balances to meet the Company's cash requirements during 
at least the next twelve months, to the extent that such funds are 
insufficient to fund the Company's activities, the Company may need to raise 
additional funds through public or private equity or debt financing from 
other sources.  The sale of additional equity or additional convertible debt 
may result in additional dilution to the Company's stockholders and such 
securities may have rights, preferences or privileges senior to those of the 
Common Stock. There can be no assurance that additional equity or debt 
financing will be available when required or, if available, will be on terms 
satisfactory to the Company. 

MERGER WITH CONCEPT SYSTEMS DESIGN, INC.

On July 24, 1998, the Company completed its acquisition of Concept. The
transaction was achieved through the merger of a wholly-owned subsidiary of the
Company with and into Concept. In connection with the merger, the Company issued
795,138 shares of Common Stock to the former shareholders of Concept.  The
former shareholders of Concept also may acquire up to 547,569 additional shares
of the Company's Common Stock in connection with the merger if certain
conditions are met prior to the end of the first twenty-four full calendar
months following the closing of the transaction. The merger has been accounted
for as a purchase. 

The purchase price of the acquisition was $4,689,000 which included $650,000 of
estimated acquisition related costs.  The purchase price was allocated as
follows:

<TABLE>
<CAPTION>

<S>                                                       <C>
Property and equipment                                    $  3,055,000
Current and other assets                                     4,041,000
Liabilities assumed                                        (13,570,000)
Goodwill                                                        36,000
Acquired in process research and development                 5,750,000
Acquired developed technology and workforce                  5,377,000
                                                          ------------

    Total                                                 $  4,689,000
                                                          ------------
</TABLE>

                                      10

<PAGE>

The goodwill, acquired developed technology and workforce are recorded on the 
balance sheet as other assets and will be amortized on a straight-line basis 
over periods ranging from 3 to 7 years.

The acquired in process research and development was expensed at the time of the
acquisition as a one-time charge.

                                      11

<PAGE>

PART II -- OTHER INFORMATION

     
Item 3.   Quantitative and Qualitative disclosures About Market Risk
     
          Not Applicable 
          
ITEM 5.   OTHER INFORMATION.
     
          Not Applicable
     
ITEM 6.   EXHIBITS AND REPORTS ON FORM 8-K.
      
     (a)  Exhibits

          Exhibit 27 (Electronic filing only)
               
     (b)  Reports on Form 8-K
          
          Form 8-K filed August 6, 1998 reporting the acquisition of Concept
          Systems Design, Inc. by the Company
          
          Form 8-K/A filed September 28, 1998 amending the Company's Form 8-K
          filed August 6, 1998 to include the financial statements of Concept
          Systems Design, Inc. and pro forma financial information.

                                      12

<PAGE>

                                   SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, as 
amended, the registrant has duly caused this Amendment No. 1 to its Quarterly 
Report on Form 10-Q.

Date: November 18, 1998                      MATTSON TECHNOLOGY, INC.

                                               /s/  Richard S. Mora
                                          ------------------------------------
                                                    Richard S. Mora
                                               Vice President of Finance
                                              and Chief Financial Officer
                                            (as principal financial officer
                                              and on behalf of Registrant)

                                      13