SPIE MICROLITHOGRAPHY , SAN JOSE , Calif., February 21, 2006--Cymer, Inc. (Nasdaq NM: CYMI), the world's leading supplier of deep ultraviolet (DUV) excimer laser light sources used in semiconductor manufacturing, today announced an agreement to collaborate with KLA-Tencor (NASDAQ: KLAC), the leading supplier of process control and yield management solutions for the semiconductor industry. As part of the agreement, Cymer will provide details of light source spectra to be incorporated into KLA-Tencor's industry-standard PROLITH lithography optimization tool . In addition, the companies expect to continue to jointly develop enhancements to this capability for future PROLITH revisions.

Through this collaboration, Cymer and KLA-Tencor plan to leverage their proven technology expertise to deliver increased accuracy, giving users immediate access to a more accurate representation of the complete optical lithography process. As a result, customers can optimize their lithography processes much faster, thus reducing their time-to-production and maximizing overall return on investment (ROI), critical differentiators for success in today's advanced lithography arena.

"The effect of laser bandwidth on critical dimensions (CD) becomes more significant with higher numerical apertures (NA) and shrinking process windows. As these effects become progressively greater, we see a growing need to provide a more accurate representation of the light source spectrum available to our customers," said Edward Charri er, General Manager, Process Analysis Division, KLA-Tencor. "By leveraging Cymer's laser spectral data and expertise, we can offer customers a truly comprehensive representation of the complete optical lithography process, and provide an added level of accuracy."

The PROLITH advanced lithography process optimization tool provides users with insight into the effects of lithography process variables while evaluating process performance improvements. With the new enhancements, c ustomers using PROLITH will be able to model the effects of changes in light source spectral characteristics on their advanced lithography processes, and use these results to better optimize their process to minimize the effects of the variations.

"We have been collaborating with KLA-Tencor on simulating the impact of laser bandwidth on CD for over five years and are pleased to join forces, once again, to meet a critical industry need with the development of the latest version of PROLITH ," said Nigel Farrar, Cymer"s vice president Lithography Applications Marketing . "KLA-Tencor's integration of our bandwidth data into PROLITH builds on Cymer's extensive research into the effect of laser bandwidth on imaging and provides customers with enabling technology for next-generation lithography."

The latest update of PROLITH, version 9.3.1, is availa ble to users now.

Forward Looking Statements
Statements in this press release that are not strictly historical in nature are forward-looking statements. These statements include, but are not limited to, references to Cymer providing light source spectra for KLA-Tencor's PROLITH tool and expectations for the tool's performance; the companies' joint development of the tool's future enhancements; the benefits that KLA-Tencor's customers may be expected to realize from using this tool; the apparent need to make this tool available to KLA-Tencor's customers due to the requirement for increasing accuracy in semiconductor photolithography processes and the growing need to be able to measure the effectiveness and accuracy of lithography processes currently utilized in production; and the potential benefits that Cymer's expertise may make available to KLA-Tencor and its customers. Each of these statements is based only on current information and expectations that are inherently subject to change and involve a number of risks and uncertainties. Actual events or results may differ materially from those projected in such statements due to various factors, including but not limited to: the possibility that the PROLITH tool will not perform up to expectations or that a competitor's tool may prove to be superior; the demand for semiconductors in general, and, in particular, for leading-edge devices with smaller geometries that require more rigorous lithography capabilities; delays or cancellations by customers of their orders; new and enhanced product offerings by competitors; the timing of customer orders, shipments and acceptances; inability by the company to meet its production and/or product development schedules; inability of the company to secure adequate supplies of critical components for its products; and the inability of the partners in this partnership to continue to improve the PROLITH tool as anticipated. For a discussion of these and other factors which may cause actual events or results to differ from those projected, please refer to KLA-Tencor's or Cymer's most recent annual report on Form 10-K and quarterly reports on Form 10-Q, as well as other subsequent filings with the Securities and Exchange Commission.

About Cymer
Cymer, Inc. is the world's leading supplier of DUV illumination sources, the essential light source for DUV photolithography systems. DUV lithography is a key enabling technology that has allowed the semiconductor industry to meet the exacting specifications and manufacturing requirements for volume production of today's advanced semiconductor chips. Further information on Cymer may be obtained from the Company's SEC filings, on the Internet at www.cymer.com or by contacting the company directly.

About KLA-Tencor
KLA-Tencor is the world leader in yield management and process control solutions for semiconductor manufacturing and related industries. Headquartered in San Jose, Calif., the company has sales and service offices around the world. An S&P 500 company, KLA-Tencor is traded on the Nasdaq National Market under the symbol KLAC. Additional information about the company is available on the Internet at http://www.kla-tencor.com

Contact:
Meggan Powers
Director Corporate Communications