US Patent 10157928 Semiconductor devices and methods of manufacture thereof

A method of forming an SRAM cell includes forming a first vertical pull-down transistor, a second vertical pull-down transistor, a first vertical pass-gate transistor, and a second vertical pass-gate transistor over a semiconductor substrate. The method includes forming a first conductive trace over a top surface of the first vertical pull-down transistor and the first vertical pass-gate transistor, forming a second conductive trace over a top surface of the second vertical pull-down transistor and the second vertical pass-gate transistor, and forming a first vertical pull-up transistor over a first portion of the first conductive trace. The method also includes forming a second vertical pull-up transistor over a first portion of the second conductive trace. The method also includes forming a first via over the first conductive trace and forming a second via over the second conductive trace.