Wisconsin Center for Applied Microelectronics

1550 Engineering Drive Phone: 608/262-6877

Madison, WI 53706 Fax: 608/265-2614

NIKON STEPPER NSR-2005i8A

Process Description:

Lithography is a process for optically projecting an image onto a wafer that has been coated with a thin layer of photosensitive material called photoresist. Projection lithography is a pattern transfer method that allows for sub-micron resolution. When UV light passes through the pattern area of a chrome mask, it exposes the photoresist on the wafer and a chemical process occurs. After a developing solution bath and rinse, a pattern is transferred via the remaining photoresist on the wafer. The remaining pattern will depend on the polarity of the photoresist (Positive or Negative). The next process steps, such as etching or ion implanting, can then be performed.

Equipment Description:

The NIKON NSR-2005i8A utilizes a reticle that must meet NIKON’s reticle design guide specifications that is provided to the User. The wafer stage can accommodate wafers with diameters of 2”, 3”, or 4”. Smaller square or rectangular substrates require a fixed jig such as a wafer that has a mountable slot that has been milled out of the wafer substrate. Note that resolution might be hampered when using mountable fixtures. The 1750 Watt Hg lamp provides exposure irradiation in the i-line portion of the spectrum resulting in a resolution as small as 0.5um. The stage movement via laser interferometry and laser enhanced alignment schemes allow for a stepping repeatability of 70nm with an overlay accuracy of 3s £ 0.18 mm. The maximum chip exposure area is 21mm x 21mm when the entire reticle is exposed. The “blinding” capability of the Stepper allows for the exposure of designated parts of the reticle allowing for greater flexibility in pattern development.

Approved Materials for use in this equipment:

Check the APPROVED MATERIALS for this equipment on http://mywebscape.wisc.edu under WCAM in the group directories.

Date last modified: 12/22/2017

Date created: 12/22/2017

Content by: Rebecca Bauer/Edward Gonzales