Read-Only Memory Using Dual MOS Transistors to Eliminate Extra Masks
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Solution Overview
Problem
The manufacturing of mask read-only memory requires extra mask plates to form storage units with different threshold voltages, increasing costs and manufacturing time.
Innovation Solution
A read-only memory design using two types of MOS transistors with the same or inverse types of sources and drains, eliminating the need for extra mask plates by integrating the manufacturing process with existing MOS device processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If extra mask plates are used to form storage units with different threshold voltages, then the manufacturing precision of storage units is improved, but the manufacturing cost and manufacturing time increase
Solution Approach 1:
The patent merges the formation of different storage unit types into a single ion implantation process by combining multiple mask patterns into one composite mask plate. This allows first and second storage units with different threshold voltages to be formed simultaneously in one manufacturing step, eliminating the need for separate mask plates and reducing the manufacturing cycle while maintaining precision.
Solution Approach 2:
The single mask plate serves multiple functions by incorporating different mask patterns for forming both first storage units and second storage units. This multi-functional mask plate replaces what would traditionally require multiple specialized mask plates, reducing manufacturing complexity and time while achieving the same precision outcomes.
2Manufacturing precision
If extra mask plates are used to form storage units with different threshold voltages, then the manufacturing precision of storage units is improved, but the manufacturing cost increases
Solution Approach 1:
The patent combines multiple mask functions into a single mask plate, reducing the total number of mask plates required from multiple to one. This merging reduces material costs, fabrication costs, and handling costs associated with multiple mask plates, while the integrated design maintains the precision needed for forming different storage unit types.
Solution Approach 2:
The universal mask plate performs multiple functions by containing different mask patterns for various storage unit formations. This single multi-functional component replaces several single-purpose mask plates, reducing overall manufacturing cost while maintaining the precision required for different threshold voltage formations.
3Manufacturing precision
If multiple mask plates are used to form different storage units, then the device complexity increases, but the manufacturing precision is improved
Solution Approach 1:
The patent merges multiple mask plate functions into a single integrated mask plate structure. By combining different mask patterns that define first storage units and second storage units into one plate, the system complexity is reduced from managing multiple separate mask plates to managing a single composite mask plate, while precision is maintained through careful integration of patterns.
Data Source
AI summary
A read-only memory includes a plurality of storage units arranged in an array. The read-only memory includes two kinds of storage units with different structures, the two kinds of storage units with different structures are a first MOS transistor and a second MOS transistor. A source and a drain of the first MOS transistor have the same type, a source and a drain of the second MOS transistor have inverse type. These two kinds of MOS transistors can be used to store binary 0 and 1 respectively. In the manufacturing method of the read-only memory, the same type of drain and source can be manufactured simultaneously, no extra mask plate is needed, so the extra mask plate of a conventional read-only memory can be saved.