Memory devices are typically provided as internal, semiconductor, integrated circuits in computers or other electronic devices. There are many different types of memory including random-access memory (RAM), read only memory (ROM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), and non-volatile (e.g., flash) memory.
In a continuing process of forming ever increasing number of memory cells on an integrated circuit wafer, memory manufacturers have relatively recently begun development of three-dimensional (3D) memory formed using semiconductor pillars. The process of forming vertical strings of memory cells along such pillars can create a thermal budget (e.g., total amount of thermal energy transferred to the wafer during an elevated temperature operation) that can damage other circuitry on the wafer. This problem can be exacerbated by the thermal budget used in forming multiple layers of these pillars on the same wafer.
There are general needs to make more compact memory devices without damaging memory support circuitry.