Reducing cross-wafer variability for minimum width resistors
AssigneeTexas Instruments Incorporated
InventorMahalingam Nandakumar
Life of this patent
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Abstract
Fabrication of an integrated circuit includes forming a photoresist layer over a substrate. Target regions defined on the substrate are exposed using a reticle that defines a first exposure window for a first doped structure of a first type; the first exposure window has a first plurality of openings and a first plurality of dopant blocking regions. A respective exposure dose for each of the target regions is determined by an exposure map and provides controlled variations in the size of the first plurality of openings across the plurality of target regions. Subsequent to the exposure and to developing the photoresist, a dopant is implanted into the substrate through the first plurality of openings.
Claims18
A method, comprising:
- forming multiple instances of a polysilicon structure on a substrate including a first instance of the polysilicon structure and a second instance of the polysilicon structure;
- forming a photoresist layer over the substrate;
- exposing a first portion of the photoresist layer using a first exposure dose through a reticle that defines an exposure pattern having a plurality of openings, the first portion of the photoresist layer covering the first instance of the polysilicon structure;
- and
- exposing a second portion of the photoresist layer using a second exposure dose through the reticle, the second portion of the photoresist layer covering the second instance of the polysilicon structure, and the second exposure dose being different than the first exposure dose, wherein the first and second exposure doses are based on an exposure map which specifies the first and second exposure doses.
A method, comprising:
- forming multiple instances of a polysilicon resistor on a wafer including a first instance of the polysilicon resistor and a second instance of the polysilicon resistor;
- forming a photoresist layer over the wafer;
- exposing a first portion of the photoresist layer using a first exposure dose through a reticle that defines an exposure pattern having one or more openings, the first portion of the photoresist layer covering the first instance of the polysilicon resistor;
- and
- exposing a second portion of the photoresist layer using a second exposure dose through the reticle, the second portion of the photoresist layer covering the second instance of the polysilicon resistor, and the second exposure dose being different than the first exposure dose, wherein the first and second exposure doses are based on an exposure map which specifies the first and second exposure doses.
Dependencies are inferred from the claim text.