Lithography is a multistep process that requires creating a mask or reticle, depositing photoresist, exposing a wafer and developing the resist. The reticle is the medium by which a stepper can transfer a chip design from an engineer's computerized layout to the wafer. In a typical wafer process, as many as 30 reticles may be required to build a chip. Each of these reticles will vary in design content and specifications.

Reticle Technology
Ultratech wafer steppers manufactured at the San Jose facility use a Wynne-Dyson lens design and 1X reticle technology. Using this approach the reticle image size is the same as the size of the image exposed on the substrate. Ultratech wafer steppers manufactured at the Wilmington facility use reduction lenses as the means of creating images on substrates. Reduction reticles images are n-times (10X, 5X, and 4X) larger than the resulting substrate images.

1X reticle technology brings a number of advantages to Ultratech customers. The advantages include smaller imaging and quality areas than reduction reticles and aligner masks, the ability to place multiple layers on a single reticle and the need for a pellicle on only one side of the reticle. Steppers utilizing 1X reticles are designed to use either 3x5x090", 5x5x090", 6x6x090", or 6x6x250" reticles, depending on the stepper model, lens (field) size, customer needs, and other factors. Current 1X steppers are specified at resolutions down to 0.65 µm

Reduction steppers manufactured at the Wilmington facility are specified at resolutions down to 0.13 µm and are designed to use 5x5x090", 5x5x0.250", or 6x6x0.250" reticles. Reduction ratios are either 4X, 5X, or 10X, depending upon the stepper model.

Reduction reticles have the advantage of larger reticle dimensions while at the same time offering smaller resolution at the wafer.

Reticle Engineering Department
Ultratech's Reticle Engineering department was established early in the company's history to support and advance state-of-the-art Ultratech reticle technology. The group accomplishes this by addressing four basic areas:

• Customer support
• Vendor support (mask vendors and mask equipment suppliers)
• Research and development
• Internal engineering support

Upon request, the Reticle Engineering group provides reticle training for customers in need of help with reticle layout, manufacturing, finishing and the use of Ultratech’s Atlas and Retman reticle and wafer management programs. See Reticle Engineering Support for details.

Reticle Alliances
Ultratech has strategic alliances with the two largest US and international photomask manufacturers: DuPont Photomasks, Inc., and Photronics, Inc. These companies, with Ultratech collaborate to develop strategies that address industry demands for reticles used in a wide variety of microlithography applications. Working together to understand shared market requirements and direction, the companies focus on sales and marketing efforts as well as the development, application and support of each participant's technology.

Reticle Suppliers
Reticle suppliers are located throughout the world to meet Ultratech customer's needs. Merchant suppliers include:

• DuPont Photomasks, Inc. (Ultratech strategic alliance partner)
• Compugraphics USA and International
• Dia Nippon Printing
• Hoya Corp.
• Photo Sciences
• Taiwan Mask Corp.
• Toppan Printing Co.

(If we have inadvertently overlooked any merchant reticle supplier that would like to be on this list, please contact Ultratech Reticle Engineering.)