Bell Labs Innovations for Lucent Technologies
	Author's Name	John P. Franey
8/2/01	Address	1B301 600 Mountain Avenue Murray Hill, NJ 07974-0636
	Telephone 908-582-2490	EMAIL jpf@lucent.com
	Facsimile 908-582-6290

Subject: Photo Mask Corrosion

Figure 1

An assessment of the protective ability of Intercept Technology and VCI on photo masks has been performed.

One sample of a photo mask was cleaned with an isopropanol dip, dried in flowing nitrogen and cut into two pieces each being approximately 6" X 8". One piece was placed in a standard 0.008" thick one sided static intercept bag. The second was placed in an over-wrap of 0.006" thick X 14.5" X 11.5"VCI impregnated paper as supplied by the photo-mask manufacturer. This Kraft wrapped mask was placed in a .003" LDPE plastic bag and heat-sealed.

The test chamber was an 8-liter bell jar, which was placed on a Thermolyne magnetic stirrer hot plate. A one-inch Teflon coated stirring bar along with 25 ml of dionized water was placed in the bottom of the vessel. The two bags were placed in the bell jar suspended 3" above the bottom on an open ceramic shelf.

The stirred was set at a medium rate and the temperature set at 110 degrees F.

The test duration was 45 Days.

The results are seen in figure 1.

The high permeation rate of the LDPE bag and long-term exposure to condensed water cause a catastrophic failure of the VCI scheme.

There was a fingerprint on the edge of the screen protected in Intercept - a site of contamination. The Intercept bag had a pinhole in the bottom seam that allowed water to accumulate inside the bag right in the proximity of the fingerprint. The active neutralization function of the Intercept Technology limited corrosion products to the immediate area surrounding the pinhole. This points up the need to ensure that all product going into Intercept bags be clean and non-contaminated.