Patent ID: 11862561
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H  B | IPC H

Claim 0:
1. A method of forming a structure, the method comprising:
forming a first transistor and a second transistor over a first substrate, forming the first transistor comprising:
forming a first fin over the first substrate;
etching a first recess and a second recess in the first fin, the first recess having a greater depth than the second recess;
depositing a sacrificial epitaxial material in the first recess, the second recess remaining free of the sacrificial epitaxial material; and
forming a first source/drain region in the first recess and a second source/drain region in the second recess;

forming a front-side interconnect structure over the first transistor and the second transistor;
etching at least a backside of the first substrate to expose the first transistor and the second transistor;
after etching the at least the backside of the first substrate, etching an additional portion of the backside of the first substrate to form a third recess and a fourth recess;
depositing a first dielectric layer in the third recess and the fourth recess;
etching the sacrificial epitaxial material to expose the first source/drain region of the first transistor and a third source/drain region of the second transistor;
forming a first backside via in the third recess and electrically connected to the first transistor;
forming a second backside via in the fourth recess and electrically connected to the second transistor;
depositing a second dielectric layer over the first backside via and the second backside via;
forming a first conductive line in the second dielectric layer, the first conductive line being a power rail electrically connected to the first transistor through the first backside via; and
forming a second conductive line in the second dielectric layer, the second conductive line being a signal line electrically connected to the second transistor through the second backside via.