Accurate Measurement of Silicon Dopants Dopants are elements, such as boron and phosphorus, that must be precisely inserted into the silicon lattice to achieve desired device characteristics. Our fourier transform infrared spectrometers, or FTIRs, enable silicon semiconductor device and wafer manufacturers to measure the amount of dopants in the silicon lattice and the thickness of differently-doped silicon layers used to form transistors

EX-4.3 4 v97043a1exv4w3.txt EXHIBIT 4.3 Exhibit 4.3 ACCENT OPTICAL TECHNOLOGIES, INC. 520 Clyde Avenue Mountain View, CA 94043 Dated as of September 30, 2000 To Certain Securityholders of Accent Optical Technologies, Inc.: Reference is made to that certain Securityholders Agreement dated as of July 31, 2000 (the "Agreement") by and among JFI II, L.P., Peter M. Joost, Bruce C. Rhine and Martha H. Rhine, David Johnson, as Trustee of the Rhine 2000 Children's Trust, Bio-Rad Laboratories, Inc., the initial additional securityholders and the initial management securityholders. Section 4.1 of the Agreement is hereby amended by deleting the reference to "60 days" in the proviso at the end of such Section 4.1 and substituting in lieu thereof a reference to "90 days". Except as specifically provided for by this letter, the Agreement shall remain in full force and effect and is hereby ratified and confirmed. This letter may be executed in any number of counterparts, each of which will be an original, but all of which together will constitute one instrument. If this letter expresses your understanding with respect to the matters described herein, please sign this letter where indicated below and return (i) a copy of such executed letter via facsimile to O'Melveny & Meyers LLP, fax number ###-###-####, Attention: Brian Hutchings, and (ii) the original of such executed letter via courier to O'Melveny & Myers LLP, 153 East 53rd Street, New York, NY 10022, Attention: Brian Hutchings. Very truly yours, ACCENT OPTICAL TECHNOLOGIES, INC. By:/s/ Bruce C. Rhine ------------------------------ Name: Bruce C. Rhine Title: President ACKNOWLEDGED AND AGREED AS OF THIS 20th DAY OF OCTOBER 2000: JFI II, L.P. By: Joost Enterprises Corporation Its: General Partner By: /s/ Peter M. Joost ---------------------------- Name: Peter M. Joost Title: President /s/ Peter M. Joost - -------------------------------------- Peter M. Joost /s/ Bruce C. Rhine - -------------------------------------- Bruce C. Rhine /s/ Martha H. Rhine - -------------------------------------- Martha H. Rhine /s/ David Johnson - -------------------------------------- David Johnson, as Trustee of the Rhine 2000 Children's Trust BIO-RAD LABORATORIES, INC. By: /s/ Sanford S. Wadler ----------------------------------- Name: Sanford S. Wadler Title: Vice President /s/ Stephen R. Blight - -------------------------------------- Stephen R. Blight /s/ Gregory A. Kaiser - -------------------------------------- Gregory A. Kaiser /s/ Brian R. Hale - -------------------------------------- Brian R. Hale /s/ Gregory A. Kaiser - -------------------------------------- Gregory A. Kaiser