<PAGE>

                                                                      EXHIBIT 12
                           Axcelis Technologies, Inc.

                Computation of Ratio of Earnings to Fixed Charges
                             (Dollars in Thousands)

<TABLE>
<CAPTION>
                                                                         Year Ended December 31                  Three Months Ended
                                           1997            1998           1999          2000           2001        March 31, 2002
                                         --------        --------       --------      --------       --------    ------------------
<S>                                    <C>             <C>              <C>          <C>            <C>              <C>
Income (loss) before income taxes       $ (61,364)      $(133,137)       $19,553      $144,272       $(40,401)       $(27,862)
Share of undistributed income of              -               -           (1,338)      (19,570)           -               -
  50% owned affiliate

Share of distributed income of                -               -              -             375            -               -
  50% owned affiliate

Interest portion of rental expense            -               -            1,430         2,340            -               -
                                         --------       ---------        -------      --------       --------        --------
  Earnings                               $(61,364)      $(133,137)       $19,645      $127,417       $(40,401)       $(27,862)
                                         ========       =========        =======      ========       ========        ========
Interest portion of rental expense            -               -            1,430         2,340            -               -
                                         --------       ---------        -------      --------       --------        --------
  Fixed charges                               -               -          $ 1,430      $  2,340            -               -
                                         --------       ---------        =======      ========       --------        ========

Ratio of earnings to fixed charges (A)      (B)             (B)             13.7          54.5          (B)             (B)
                                         ========       =========        =======      ========       ========        ========
</TABLE>


(A)  For purposes of calculating the ratio of earnings to fixed charges,
     earnings consist of the sum of income before income taxes, fixed charges
     and the Company's share of distributed income from a 50% owned affiliate
     offset by the Company's share of undistributed income from a 50% owned
     affiliate. Fixed charges include the portion of rental expense under
     operating leases deemed by the Company to be representative of the interest
     factor in rent expense.

(B)  During the fiscal years ended December 31, 1997, 1998 and 2001 and the
     fiscal quarter ended March 31, 2002, there was a deficiency of earnings to
     cover fixed charges of approximately $61.4 million, $133.1 million,
     $40.4 million and $27.9 million, respectively.

