BACKGROUND

Microprocessors which include in the same family microcontrollers, ASICs and various chips having one or more CPUs on a single die, frequently include a block of SRAM. When a block of SRAM is included on a microprocessor, some of the process steps carried out in making the microprocessor can also be used to make the SRAM. To make this possible, the SRAM should be designed in such a way to be compatible with the process technology used in making the microprocessor. The different layers of material which are available while the microprocessor is constructed should be used in the SRAM cell. This presents different challenges than when manufacturing a stand-alone SRAM chip.

If the SRAM memory cell can be constructed using the same masks, materials, deposition process steps, insulation layers and other process technology used while making the microprocessor, then this saves the need to create special masks and process steps for structures that are inside the SRAM cell, while reduces the total masks needed for making the microprocessor chip as a whole.

