Exhibit 99.1


For Immediate Release
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                      ATMI INVESTS IN ANJI MICROELECTRONICS
                     Expands Copper Materials Opportunities

      DANBURY, CT -- July 13, 2005 -- ATMI, Inc. (Nasdaq: ATMI), a supplier of
materials and materials packaging to the world's leading semiconductor
manufacturers, today announced it has purchased a minority interest in Anji
Microelectronics, a developer of advanced semiconductor materials located in
Shanghai, China.

      The two companies will work together to develop and market advanced
materials that leverage the skills and expertise of both groups: ATMI is a
leader in many of the performance materials used in copper-based
semiconductor manufacturing; Anji has expertise and strong focus in advanced
semiconductor materials development.

      "ATMI is focused on providing the world's leading integrated circuit
producers the highest performing materials and applications support for their
most demanding applications," said Doug Neugold, Chief Executive Officer of
ATMI. "Anji's technical capabilities, world-class people, and position as one
of the first pure-play performance semiconductor materials companies in China
will enable both companies to develop and deliver even better solutions for
our customers."

      "The Anji/ATMI technical collaboration should present significant
market opportunities for new leading edge performance materials," said Tod
Higinbotham, ATMI Senior Vice-President and General Manager of Materials,
"particularly in cleans and planarization."


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      Anji Microelectronics, a high-tech company with operations in China, is
focused on high growth and high performance semiconductor materials. Anji
Microelectronics works with major semiconductor manufacturers in meeting
their roadmap and performance needs. For more information, please visit
www.anjimicro.com.

      ATMI provides specialty materials and materials packaging to the
worldwide semiconductor industry. As the Source of Semiconductor Process
Efficiency, ATMI helps customers improve wafer yields and lower operating
costs. For more information, please visit www.atmi.com.


Statements contained herein that relate to ATMI's future performance,
including, without limitation, statements with respect to ATMI's anticipated
results of operations or level of business for 2005 or any other future
period, are forward-looking statements within the safe harbor provisions of
the Private Securities Litigation Reform Act of 1995. Such statements are
based on current expectations only and are subject to certain risks,
uncertainties, and assumptions, including, but not limited to, changes in
semiconductor industry growth (including, without limitation, wafer starts)
or ATMI's markets; competition, problems, or delays developing and
commercializing new products; problems or delays in integrating acquired
operations and businesses; and other factors described in ATMI's filings with
the Securities and Exchange Commission. Such risks and uncertainties may
cause actual results to differ materially from those expressed in our
forward-looking statements. ATMI undertakes no obligation to update any
forward-looking statements.

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For more information contact:
      Dean Hamilton
      ATMI Investor & Public Relations
      203.207.9349 Direct
      203.794.1100 x4202
      dhamilton@atmi.com
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