EXHIBIT 10.19

                                                    LOAN MODIFICATION AGREEMENT

         This  agreement  amends the  Promissory  Note dated  September 29, 1997
("Note")  executed by  SEMITOOL,  INC  ("Borrower")  in favor of Bank of America
National  Trust  and  Savings  Association,  doing  business  as  Seafirst  Bank
("Bank"),  regarding a loan in the maximum  principal  amount of  $10,000,000.00
(the  "Loan").  For mutual  consideration,  Borrower and Bank agree to amend the
above loan documents as follows:

         1.       Interest Rate.  The Adjusted LIBOR Rate margin as shown in 
Exhibit A, Article 1 to the note is changed to 1.75%

         2. Other Terms. Except as specifically amended by this agreement or any
prior amendment,  all other terms,  conditions,  and definitions of the Note and
all other security agreements,  guaranties, deeds of trust, mortgages, and other
instruments  or agreements  entered into with regard to the Loan shall remain in
full force and effect.

         DATED October 2, 1997.


Bank:                                           Borrower:

SEAFIRST BANK                                   SEMITOOL, INC

By     /s/Joe Poole                             By: /s/Raymon F. Thompson
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Title    VP                                       Raymon F. Thompson, President