US 11,869,756 B2
Virtual metrology enhanced plasma process optimization method
Jun Shinagawa, Fremont, CA (US); Toshihiro Kitao, Austin, TX (US); Atsushi Suzuki, Austin, TX (US); Megan Wooley, Austin, TX (US); and Alok Ranjan, Austin, TX (US)
Assigned to Tokyo Electron Limited, Tokyo (JP)
Filed by Tokyo Electron Limited, Tokyo (JP)
Filed on Jun. 17, 2021, as Appl. No. 17/350,439.
Prior Publication US 2022/0406580 A1, Dec. 22, 2022
Int. Cl. G06F 30/398 (2020.01); H01J 37/32 (2006.01)
CPC H01J 37/32926 (2013.01) [G06F 30/398 (2020.01); H01J 2237/334 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of optimizing a recipe for a plasma process, comprising:
(a) building a virtual metrology (VM) model that predicts a wafer characteristic resulting from the plasma process based on a plasma parameter;
(b) building a control model that describes a relationship between the plasma parameter and a recipe parameter;
(c) measuring the wafer characteristic after performing the plasma process according to the recipe;
(d) determining whether the wafer characteristic is within a predetermined range;
(e) calibrating the VM model and the control model based on the wafer characteristic;
(f) optimizing the recipe by updating the plasma parameter based on the wafer characteristic using the VM model and updating the recipe parameter based on the plasma parameter using the control model; and
(g) repeating (c), (d), (e) and (f) until the wafer characteristic is within the predetermined range,
wherein calibrating the control model comprises:
performing the plasma process on a dummy wafer according to the recipe;
recording the plasma parameter while performing the plasma process on the dummy wafer according to the recipe; and
updating the control model based on the plasma parameter recorded.