Patent ID: 9039907
Filing Date: 2015-05-26
Classification: G01B,G01N,H01L

Abstract:
1. A method for improving the uniformity over a predetermined substrate area of a spectral response of photonic devices fabricated in a device layer of a Silicon-On-Insulator substrate, wherein the device layer of the Silicon-On-Insulator substrate is a silicon device layer on a silicon dioxide layer, the method comprising: before fabrication of the photonic device structures in the device layer of the Silicon-On-Insulator substrate, (i.) establishing an initial device layer thickness map for the predetermined area; (ii) establishing an anticipated linewidth map for the predetermined area, wherein establishing the anticipated linewidth map comprises establishing, based at least on previously-collected process control data from optical lithography and from dry etching, an anticipated linewidth as a function of spatial wafer coordinates in the predetermined area; (iii) establishing an anticipated etch depth map for the predetermined area, wherein establishing the anticipated etch depth map comprises establishing, based at least on previously-collected process control data from optical lithography and from dry etching, an anticipated etch depth as a function of spatial wafer coordinates in the predetermined area; (iv) based at least on the initial device layer thickness map, the anticipated linewidth map and the anticipated etch depth map, calculating (i) an optimal device layer thickness map for matching a predetermined spectral response of a photonic device and (ii) a corresponding thickness correction map for the predetermined substrate area taking into account photonic device design data; and (v) performing a location specific corrective etch process in accordance with the thickness correction map.