Hello, We are working on a MEMS project with Auburn University and we use 4 inch 1:1 contact masks. Harris Corp. makes the masks for $500 each, which is a good price for 4 inch masks. They might make 5 inch masks also. Charles Ellis at Auburn University can give you the contact information for Harris Corp. His phone nummber is: (334) 844-1883. Sincerely, Robert Dean RF CMOS Designer / Project Manager MEMS Optical, Inc. 205 Import Circle Huntsville, AL 35806 (256) 859-1886 Voice (256) 859-5890 Fax