Memory Cell Layout VSS Terminal Sharing
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Solution Overview
Problem
Non-optimized layouts of memory cells in integrated circuits lead to increased die area and degraded read speed due to additional circuitry and loads, which can be exacerbated by the presence of unnecessary strap cells between memory segments.
Innovation Solution
The VSS region of a strap cell and the VSS region of a bit cell in a memory macro share a common first VSS contact terminal, while the VSS region of a read port in one segment shares a second VSS contact terminal with another read port in a different segment, eliminating the need for strap cells between segments, thus reducing die area and improving read speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strap cells are placed between memory segments, then the memory macro structure is complete and functional, but the die area increases and read speed degrades due to additional loads
Solution Approach 1:
The patent removes the strap cell from between the first and second memory segments, eliminating the additional load on the read bit line. The VSS contact terminal is directly connected to the VSS region of the first memory segment without requiring a strap cell, thus improving read speed while maintaining functionality.
Solution Approach 2:
The patent merges the VSS contact terminal directly with the VSS region of the first memory segment, eliminating the intermediate strap cell structure. This consolidation reduces the number of components and their associated parasitic capacitances, thereby improving read speed.
2Reliability
If strap cells are placed between memory segments, then the memory macro structure is complete, but the die area increases
Solution Approach 1:
The strap cell is extracted and removed from the memory macro structure. The VSS contact terminal is directly connected to the VSS region without requiring the strap cell, reducing the overall die area while maintaining the functional integrity of the memory macro.
Solution Approach 2:
The VSS contact terminal is merged directly with the VSS region of the first memory segment, eliminating the separate strap cell structure. This reduces the total component count and die area occupation while preserving the necessary electrical connections and functionality.
3Reliability
If additional circuitry is added to the memory layout, then the circuit functionality is enhanced, but the die area increases and read speed degrades
Solution Approach 1:
The unnecessary strap cell circuitry is removed from the memory layout. The direct connection between the VSS contact terminal and the VSS region eliminates the additional circuit elements that would otherwise increase parasitic capacitance and degrade read speed.
Data Source
AI summary
A semiconductor structure includes a first strap cell, a first read port, and a first VSS terminal. The first strap cell has a first strap cell VSS region. The first read port has a first read port VSS region, a first read port read bit line region, and a first read port poly region. The first VSS terminal is configured to electrically couple the first strap cell VSS region and the first read port VSS region.