Exhibit 10.28

                                                             DUE:  APRIL 1, 2001

                                 PROMISSORY NOTE

                                 SEMITOOL, INC.

$25,000,000.00                                         Dated: SEPTEMBER 30, 1998
                                                             Spokane, Washington

         SEMITOOL,   INC.,  a  Montana  corporation  ("Maker")   unconditionally
promises  to pay to the order of Bank of  America  National  Trust  and  Savings
Association,  doing business as SEAFIRST BANK ("Bank"), at its SPOKANE & EASTERN
TEAM #14 office, on or before APRIL 1, 2001, in immediately available funds, the
principal  sum of TWENTY FIVE MILLION AND NO/100  Dollars  ($25,000,000.00),  or
such  lesser  sum as may be  advanced  hereunder.  Maker  further  agrees to pay
interest on the daily  unpaid  principal  balance,  in arrears on the 1st day of
each month,  beginning the 1st day of NOVEMBER,  1998,  in  accordance  with the
terms, conditions, and definitions of Exhibit A attached, which are incorporated
herein.  Also  incorporated  herein is  Exhibit  1  attached  hereto,  regarding
prepayment fees.

         All advances under this Note, all conversions between the interest rate
options,  and all  payments of  principal  and  interest  may be  reflected on a
schedule or a computer-generated statement which shall become a part hereof. All
unpaid  principal and accrued but unpaid  interest under this Note shall be paid
in full on APRIL 1, 2001.

         Fee on Unutilized portion of line: on December 31, 1998 and on the last
day of each  quarter  thereafter,  Borrower  shall  pay a fee of 0.20% Per Annum
based upon a 360 day accrual basis upon the average daily unused  portion of the
line of credit.

         Bank is authorized to automatically debit each required  installment of
interest from Maker's  checking  account number  13629803 at Bank, or such other
deposit account at Bank as Maker may authorize in the future.

         If all or any portion of the  principal  amount or any  installment  of
interest  is not paid when due,  interest  shall  accrue,  at the  option of the
holder of this Note, from the date of default at a floating rate per annum three
percent (3%) above the Reference  Rate, as the Reference Rate may vary from time
to time, and the entire unpaid principal amount of this Note,  together with all
accrued interest,  shall become immediately due and payable at the option of the
holder hereof.

         Advances  under  this  Note may be made by Bank at the oral or  written
request of Raymon F Thompson,  Larry Viano,  Bill Freeman or Carrie  Oberhauser,
any one acting  alone,  who are  authorized  to request  advances and direct the
disposition  of any such advances until written notice of the revocation of such
authority is received by Bank at its office  indicated  above.  Any such advance
shall be conclusively  presumed to have been made to or for the benefit of Maker
when made in accordance with such requests and directions, or when said advances
are deposited to the credit of an account of Maker with Bank,  regardless of the
fact that persons  other than those  authorized  under this  paragraph  may have
authority to draw against such account.

         Maker  hereby  waives  presentment,  demand,  protest,  and  notice  of
dishonor  hereof.  Each party signing or endorsing  this Note signs as maker and
principal, and not as guarantor, surety, or accommodation party; and is estopped
from asserting any defense based on any capacity other than maker or principal.

         This Note shall be governed by and  construed  in  accordance  with the
laws of the State of Washington.

         ORAL AGREEMENTS OR ORAL COMMITMENTS TO LOAN MONEY, TO EXTEND CREDIT, OR
TO  FORBEAR  FROM  ENFORCING  REPAYMENT  OF A DEBT  ARE  NOT  ENFORCEABLE  UNDER
WASHINGTON LAW.

                                                SEMITOOL, INC.



                                                By:  /s/Raymon F. Thomspon
                                                     ---------------------------
                                                Its: Chairman
                                                     ---------------------------

<PAGE>





                                    EXHIBIT A
                               INTEREST PROVISIONS




                                    ARTICLE 1
                                   Definitions
         All terms defined below shall have the meaning indicated:
         1.1  Adjusted  LIBOR  Rate  shall  mean for any day that per annum rate
equal to the sum of (a) a margin of 1.50%,  (b) the Assessment Rate, and (c) the
quotient of (i) the LIBOR Rate as determined  for such day,  divided by (ii) the
Reserve Adjustment.  The Adjusted LIBOR Rate shall change with any change in the
LIBOR Rate on the first day of each Interest Period and on the effective date of
any change in the Assessment Rate or Reserve Adjustment.
         1.2  Advances  shall mean the  disbursement  of loan proceeds under the
Note.
         1.3  Assessment  Rate  shall  mean  as of any day  the  minimum  annual
percentage rate established by the Federal Deposit Insurance Corporation (or any
successor)  for the  assessment  due from members of the Bank Insurance Fund (or
any successor) in effect for the assessment  period during which said day occurs
based on deposits  maintained at such members'  offices  located  outside of the
United States.  In the event of a retroactive  reduction in the Assessment  Rate
after a commencement of any Interest Period, Bank shall not retroactively adjust
as to such Interest  Period any interest rate  calculated  using the  Assessment
Rate.
         1.4  Available Amounts shall mean $25,000,000.00 less the outstanding
principal balance of the Note.
         1.5  Bank shall mean the holder of the Note.
         1.6  Borrower shall mean the maker of the Note.
         1.7  Business Day shall mean any day other than a Saturday,  Sunday, or
other day on which  commercial banks in Seattle,  Washington,  are authorized or
required by law to close.
         1.8  Commencement  Date shall mean the first day of any Interest Period
as  requested by  Borrower.  1.9  Floating  Rate Loans shall mean those portions
of principal of the Note accruing interest at the Floating Rate.
         1.10 Floating Rate shall mean the Reference Rate plus 0.00% per annum.
         1.11 Interest  Period shall mean the period  commencing on the date of
any advance at or  conversion  to an Adjusted  LIBOR Rate and ending on any date
thereafter as selected by Borrower, subject to the restrictions of Section 0. If
any Interest Period would end on a day which is not a Business Day, the Interest
Period shall be extended to the next succeeding Business Day.
         1.12 LIBOR Rate shall mean for any Interest  Period the per annum rate,
calculated  on the basis of actual  number  of days  elapsed  over a year of 360
days,  for U.S.  Dollar  deposits  for a period  equal  to the  Interest  Period
appearing on the display  designated as "Page 3750" on the Telerate  Service (or
such other page on that service or such other service  designated by the British
Banker's  Association for the display of that Association's  Interest Settlement
Rates for U.S. Dollar deposits) as of 11:00 a.m.,  London time, on the day which
is two London  Banking  Days prior to the first day of the Interest  Period.  If
there is no period equal to the Interest  Period on the display,  the LIBOR Rate
shall be determined by straight-line interpolation to the nearest month (or week
or day if  expressed  in weeks or days)  corresponding  to the  Interest  Period
between the two nearest neighboring periods on the display.
         1.13 LIBOR Rate Loans  shall mean those  portions of  principal  of the
Note accruing interest at the Adjusted LIBOR Rate.
         1.14 London  Banking  Day shall  mean any day other  than a  Saturday,
Sunday,  or  other  day on  which  commercial  banks  in  London,  England,  are
authorized or required by law to close.
         1.15 Note  shall  mean the  promissory  note to which  this  exhibit is
attached.
         1.16 Reference Rate shall mean the rate of interest publicly  announced
from time to time by Bank in San Francisco, California, as its "Reference Rate."
The Reference Rate is set based on various  factors,  including Bank's costs and
desired return, general economic conditions, and other factors, and is used as a
reference  point for pricing some loans.  Bank may price loans to its  customers
at, above,  or below the Reference  Rate. Any change in the Reference Rate shall
take  effect at the  opening  of  business  on the day  specified  in the public
announcement of a change in the Reference Rate.
         1.17 Reserve  Adjustment  shall mean as of any day the remainder of one
minus that percentage  (expressed as a decimal) which is the highest of any such
percentages  established by the Board of Governors of the Federal Reserve System
(or any successor) for required reserves (including any emergency,  marginal, or
supplemental reserve requirement) regardless of the aggregate amount of deposits
with said member bank and without  benefit of any  possible  credit,  proration,
exemptions,  or offsets for time deposits established at offices of member banks
located outside of the United States or for eurocurrency liabilities, if any.
         1.18 Termination  Date shall mean APRIL 1, 2001,  or such earlier date
upon  which  Bank  makes  demand  for  payment in full under the Note based on a
default under the Note.



<PAGE>


                                    ARTICLE 2
                              Interest Rate Options
         2.1  Interest Rates and Payment Date. The Note shall bear interest from
the date of Advance on the unpaid  principal  balance  outstanding  from time to
time at the Floating Rate or Adjusted LIBOR Rate as selected by Borrower and all
accrued interest shall be payable in arrears as provided in the Note.
         2.2  Procedure.  Borrower  may,  on any London  Banking  Day two London
Banking Days before a Commencement  Date, request Bank to give an Adjusted LIBOR
Rate quote for a specified loan amount and Interest Period. Bank will then quote
to Borrower the available  Adjusted  LIBOR Rate.  Borrower  shall have two hours
from the  time of the  quote to elect an  Adjusted  LIBOR  Rate by  giving  Bank
irrevocable notice of such election.
         2.3  Restrictions. Each Interest Period shall be one month or two 
months or three months or six months or one year or any other term  acceptable
to Bank in its sole  discretion.  In no event shall an Interest Period extend 
beyond the Termination Date. The minimum amount of a LIBOR Rate Loan shall be 
$500,000.
         2.4  Prepayments. If Borrower prepays all or any portion of a LIBOR
Rate Loan prior to the end of an Interest Period, there shall be due at the time
of any such  prepayment the Prepayment  Fee, determined in accordance  with Form
51-6325 which is attached as Exhibit 1 to the Note.
         2.5  Reversion to Floating. The Note shall bear interest at the
Floating Rate unless an Adjusted LIBOR Rate is specifically  selected. At the
termination of any Interest Period each LIBOR Rate Loan shall revert to a
Floating Rate Loan unless Borrower directs otherwise pursuant to Section 0.
         2.6  Inability to  Participate in Market.  If Bank in good faith cannot
participate  in the  Eurodollar  market  for  legal or  practical  reasons,  the
Adjusted LIBOR Rate shall cease to be an interest rate option. Bank shall notify
Borrower of and when it again becomes legal or practical to  participate  in the
Eurodollar  market,  at which time the Adjusted LIBOR Rate shall resume being an
interest rate option.
         2.7  Costs.  Borrower shall, as to LIBOR Rate Loans, reimburse Bank for
all costs,  taxes,  and  expenses,  and defend  and hold Bank  harmless  for any
liabilities, which Bank may incur as a consequence of any changes in the cost of
participating  in,  or in the  laws or  regulations  affecting,  the  Eurodollar
market, including any additional reserve requirements, except to the extent such
costs are already  calculated  into the Adjusted LIBOR Rate. This covenant shall
survive the payment of the Note.
         2.8  Basis of Quotes. Borrower acknowledges that Bank may or may not in
any particular case actually match-fund a LIBOR Rate Loan. FDIC assessments, and
Federal Reserve Board reserve requirements,  if any are assessed,  will be based
on Bank's best  estimates of its marginal cost for each of these items.  Whether
such  estimates  in fact  represent  the actual cost to Bank for any  particular
dollar or  Eurodollar  deposit or any LIBOR Rate Loan will  depend upon how Bank
actually  chooses to fund the LIBOR Rate Loan.  By electing  an  Adjusted  LIBOR
Rate,  Borrower  waives any right to object to Bank's means of  calculating  the
Adjusted LIBOR Rate quote accepted by Borrower.



<PAGE>


                                    ARTICLE 3
                                    Advances
         3.1  Revolving Loan Facility. Bank shall until the earlier of demand or
the Termination  Date make Advances to Borrower from time to time, to the extent
of the Available  Amounts,  with the aggregate  principal amount at any one time
outstanding  not to exceed  $25,000,000.00.  Borrower  may borrow,  prepay,  and
reborrow the principal of the Note in whole or in part.
         3.2  Procedure for  Advances.  Borrower may borrow on any Business Day.
Borrower shall give Bank  irrevocable  notice  (written or oral)  specifying the
amount to be borrowed and the requested  borrowing  date. Bank must receive such
notice on or before 11:30 a.m., Seattle time, on the day borrowing is requested.
All Advances shall be  discretionary  to the extent  notification by Borrower is
given subsequent to that time.


<PAGE>





                          Exhibit 1 -- PREPAYMENT FEES

     If the  principal  balance  of this  note is  prepaid  in whole or in part,
whether by voluntary prepayment,  operation of law, acceleration or otherwise, a
prepayment fee, in addition to any interest earned,  will be immediately payable
to the holder of this note.

     The amount of the prepayment fee depends on the following:

(1)  The amount by which interest  reference rates as defined below have changed
     between  the time the loan is  prepaid  and either a) the time the loan was
     made for fixed rate loans,  or b) the time the  interest  rate last changed
     (repriced) for variable rate loans.
(2)  A prepayment fee factor (see "Prepayment Fee Factor  Schedule" on reverse).
(3)  The amount of principal prepaid.

If the proceeds from a CD or time deposit pledged to secure the loan are used to
prepay the loan resulting in payment of an early withdrawal  penalty for the CD,
a prepayment fee will not also be charged under the loan.

              Definition of Reference Rate for Variable Rate Loans

The  "Reference  Rate" used to represent  interest rate levels for variable rate
loans  shall be the index rate used to  determine  the rate on this loan  having
maturities  equivalent  to the  remaining  period to  interest  rate change date
(repricing)  of this loan  rounded  upward to the nearest  month.  The  "Initial
Reference  Rate" shall be the Reference Rate at the time of last repricing and a
new Initial Reference Rate shall be assigned at each subsequent  repricing.  The
"Final Reference Rate" shall be the Reference Rate at the time of prepayment.

                Definition of Reference Rate for Fixed Rate Loans

The "Reference Rate" used to represent  interest rate levels on fixed rate loans
shall be the bond  equivalent  yield of the average  U.S.  Treasury  rate having
maturities  equivalent to the remaining  period to maturity of this loan rounded
upward to the nearest month. The "Initial Reference Rate" shall be the Reference
Rate at the time the loan was made.  The  "Final  Reference  Rate"  shall be the
Reference Rate at time of prepayment.

The Reference  Rate shall be  interpolated  from the yields as displayed on Page
119 of the Dow Jones  Telerate  Service  (or such  other  page or service as may
replace that page or service for the purpose of displaying  rates  comparable to
said U.S. Treasury rates) on the day the loan was made (Initial  Reference Rate)
or the day of prepayment (Final Reference Rate).

An Initial  Reference  Rate of N/A % has been assigned to this loan to represent
interest rate levels at origination.

                          CALCULATION OF PREPAYMENT FEE

If the Initial Reference Rate is less than or equal to the Final Reference Rate,
there is no prepayment fee.

If the Initial  Reference  Rate is greater than the Final  Reference  Rate,  the
prepayment  fee shall be equal to the  difference  between the Initial and Final
Reference Rates (expressed as a decimal),  multiplied by the appropriate  factor
from the Prepayment Fee Factor  Schedule,  multiplied by the principal amount of
the loan being prepaid.


<PAGE>


                      Example of Prepayment Fee Calculation

Variable Rate Loan: A non-amortizing  6-month LIBOR based loan with principal of
$250,000 is fully  prepaid  with 3 months  remaining  until next  interest  rate
change date  (repricing).  An Initial Reference Rate of 7.0% was assigned to the
loan at last  repricing.  The Final Reference Rate (as determined by the 3-month
LIBOR index) is 6.5%. Rates therefore have dropped 0.5% since last repricing and
a prepayment  fee applies.  A prepayment  fee factor of 0.31 is determined  from
Table 3 below and the prepayment fee is computed as follows:

        Prepayment Fee = (0.07 -- 0.065) x (0.31) x ($250,000) = $387.50

Fixed Rate Loan:  An  amortizing  loan with  remaining  principal of $250,000 is
fully prepaid with 24 months remaining until maturity. An Initial Reference Rate
of 9.0% was  assigned  to the loan when the loan was made.  The Final  Reference
Rate (as  determined by the current  24-month U.S.  Treasury rate on Page 119 of
Telerate) is 7.5%. Rates therefore have dropped 1.5% since the loan was made and
a prepayment  fee applies.  A prepayment  fee factor of 1.3 is  determined  from
Table 1 below and the prepayment fee is computed as follows:

         Prepayment Fee = (0.09 -- 0.075) x (1.3) x ($250,000) = $4,875

                         PREPAYMENT FEE FACTOR SCHEDULE

                         TABLE I: FULLY AMORTIZING LOANS
Proportion of Remaining Principal      Months Remaining to Maturity/Repricing(1)
Amount Being Prepaid

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------------------------------------
<S>           <C>    <C>     <C>     <C>    <C>     <C>     <C>    <C>     <C>     <C>    <C>     <C>     <C>
              0      3       6       9      12      24      36     48      60      84     120     240     360 
--------------------------------------------------------------------------------------------------------------
90-100%       0      .21     .36     .52    .67     1.3     1.9    2.5     3.1     4.3    5.9     10.3    13.1
60-89%        0      .24     .44     .63    .83     1.6     2.4    3.1     3.9     5.4    7.5     13.2    17.0
30-59%        0      .28     .53     .78    1.02    2.0     3.0    4.0     5.0     7.0    9.9     18.5    24.4
0-29%         0      .31     .63     .92    1.22    2.4     3.7    5.0     6.3     9.0    13.4    28.3    41.8
</TABLE>


                 TABLE II: PARTIALLY AMORTIZING (BALLOON) LOANS
Proportion of Remaining Principal      Months Remaining to Maturity/Repricing(1)
Amount Being Prepaid

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------------------------------------
<S>                  <C>     <C>     <C>    <C>     <C>     <C>    <C>     <C>     <C>    <C>     <C>     <C>
              0      3       6       9      12      24      36     48      60      84     120     240     360
--------------------------------------------------------------------------------------------------------------
90-100%       0      .26     .49     .71    .94     1.8     2.7    3.4     4.2     5.6    7.4     11.6    14.0
60-89%        0      .30     .59     .86    1.15    2.2     3.3    4.3     5.3     7.1    9.4     15.0    18.1
30-59%        0      .31     .63     .95    1.27    2.6     3.9    5.3     6.6     9.1    12.6    21.2    26.2
0-29%         0      .31     .63     .95    1.27    2.6     4.0    5.4     7.0     10.2   15.7    33.4    46.0
</TABLE>


                 TABLE III: NONAMORTIZING (INTEREST ONLY) LOANS
Proportion of Remaining Principal      Months Remaining to Maturity/Repricing(1)
Amount Being Prepaid

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------------------------------------
<S>           <C>    <C>     <C>     <C>    <C>     <C>     <C>    <C>     <C>     <C>    <C>     <C>     <C>
              0      3       6       9      12      24      36     48      60      84     120     240     360
--------------------------------------------------------------------------------------------------------------
0-100%        0      .31     .61     .91    1.21    2.3     3.4    4.4     5.3     6.9    8.9     13.0    14.8
</TABLE>




--------
(1) For  the   remaining   period   to   maturity/repricing   between   any  two
maturities/repricings  shown in the above  schedules,  interpolate  between  the
corresponding factors to the closest month.

The  holder  of this note is not  required  to  actually  reinvest  the  prepaid
principal in any U.S.  Government Treasury  Obligations,  or otherwise prove its
actual loss, as a condition to receiving a prepayment fee as calculated above.