US 11,852,467 B2
Method and system for monitoring deposition process
Heath A. Pois, Fremont, CA (US); Laxmi Warad, Milpitas, CA (US); and Srinivasan Rangarajan, Morgan Hill, CA (US)
Assigned to NOVA MEASURING INSTRUMENTS, INC., Fremont, CA (US)
Appl. No. 17/438,845
Filed by NOVA MEASURING INSTRUMENTS, INC., Santa Clara, CA (US)
PCT Filed Mar. 12, 2020, PCT No. PCT/US2020/022407
§ 371(c)(1), (2) Date Sep. 13, 2021,
PCT Pub. No. WO2020/190643, PCT Pub. Date Sep. 24, 2020.
Claims priority of provisional application 62/817,492, filed on Mar. 12, 2019.
Prior Publication US 2022/0155064 A1, May 19, 2022
Int. Cl. G01B 15/02 (2006.01); G01N 23/2273 (2018.01)
CPC G01B 15/02 (2013.01) [G01N 23/2273 (2013.01); G01N 2223/61 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method for monitoring deposition process, comprising:
providing a sample having a first layer of a first material deposited over a second layer of a second material, the second layer having a pattern of a third material therein;
generating an X-ray beam and directing the X-ray beam towards the sample to irradiate the sample;
intercepting part of the X-ray beam with an X-ray detector to generate an X-ray flux value;
collecting electrons emitted from the sample and separating the electrons according to electron energies;
determining electron count for each of the electron energies;
determining the presence of the first material over the pattern of the third material by using the X-ray flux value to normalize the electron count of electron energies corresponding to electrons emitted from the pattern of the third material, and comparing resulting normalized electron count to reference electron count;
wherein a first thickness of the first layer deposited over the second layer and a second thickness of the first layer deposited over the pattern are determined by:
using the electron count for each of the electron energies to generate intensity values I1, I2 and I3, corresponding to photo electrons emitted from the first, second and third materials, respectively;
calculating modeled intensities I′1, I′2 and I′3, corresponding to photo electrons emitted from the first, second and third materials using iterative estimated thicknesses values for the first thickness and second thickness;
minimizing difference between measured ratios of intensity values I1, I2 and I3, and ratios of the modeled intensities I″1, I′2 and I′3, to thereby obtain true values of the first thickness and second thickness.