Exhibit 23.1 INDEPENDENT AUDITORS' CONSENT We consent to the incorporation by reference in this Registration Statement of Nanometrics Incorporated on Form S-8 of our report dated February 15, 2000, appearing in the Annual Report on Form 10-K of Nanometrics Incorporated for the year ended December 31, 1999. /s/ DELOITTE & TOUCHE LLP - ------------------------------- DELOITTE & TOUCHE LLP San Jose, California July 5, 2000