Semiconductor Redundancy Replacement Using Multiplexer for Column Select Line Repair
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Solution Overview
Problem
Current redundancy schemes in semiconductor memory devices limit flexibility in repairing faulty memory cells, leading to unnecessary replacement of operative cells and reduced memory yield, as they rely on selecting column select line repair regions based on row group addresses, which can result in faulty column select line replacements.
Innovation Solution
A redundancy replacement scheme that repairs faulty memory cells in column select line groups using spare cells based on the physical or logical address of the selected row, allowing independent column repair decoupled from row repair, thereby maximizing the use of functioning memory cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If column select line repair region is selected based on row group address, then row repair can be performed, but flexible repair of column select line is limited and operative cells may be unnecessarily replaced
Solution Approach 1:
The patent segments the column select line repair function from the row repair function. Instead of selecting column select line repair region based on row group address, the invention independently selects column select line repair region based on column segment address, allowing separate and flexible repair of column select lines without being constrained by row repair requirements
Solution Approach 2:
The patent introduces an intermediary mechanism (multiplexer) that decouples the selection of column select line repair region from row group address. The multiplexer allows independent selection of column select line repair region based on column segment address, acting as a mediator between the address input and the column select line repair function
2Reliability
If redundant row is used to repair failing memory cell, then the failing cell's row can be replaced, but every cell in the failing cell's row is replaced including operative cells
Solution Approach 1:
The patent applies local quality by enabling selective repair at the column select line segment level rather than replacing entire rows. The repair function can be applied locally to specific column select line segments that contain failing cells, while leaving other column select lines and their associated operative cells unchanged
Solution Approach 2:
Instead of replacing entire rows (excessive action), the patent implements partial replacement by repairing only the specific column select line segments that contain failing cells. This partial action approach repairs the necessary portions while preserving operative cells in other segments
3Device complexity
If column select line repair is coupled with row repair, then repair process is simplified, but repair flexibility is reduced and faulty column select line replacements occur
Solution Approach 1:
The patent segments the repair process into independent row repair and column select line repair functions. The column select line repair is decoupled from row repair, allowing each function to operate independently with its own selection criteria, thereby maintaining flexibility while managing complexity through functional separation
Data Source
AI summary
A redundancy replacement scheme for a semiconductor device repairing a faulty memory cell in a column select line group with a spare memory cell in the column select line group based on a physical or logical address of the selected row.