Automated Cell Black Boxing for Layout Versus Schematic Checking
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Solution Overview
Problem
The conventional cell black boxing process for layout versus schematic checking is tedious, time-consuming, and requires frequent human interventions, as it involves manually locating ports of cells to be black boxed using both layout design and foundry deck files.
Innovation Solution
The method involves receiving a rule file from a chip manufacturer, determining text containers and drawn layers containing cell port information, and generating a file for cell port detection that associates these containers with relevant layout design layers. This file is used to extract cell ports and connectivity from the layout design, allowing for automated cell black boxing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional manual cell black boxing process is used, then cell ports can be located accurately using layout design and foundry deck, but the process is tedious, time-consuming and requires frequent human interventions
Solution Approach 1:
The system automatically generates the cell port detection file by having the layout versus schematic tool itself extract and process cell port information from the layout design and rule file, eliminating the need for manual human intervention in the black boxing setup process
Solution Approach 2:
The cell port detection file is generated in advance before the layout versus schematic extraction process, containing all necessary cell port location information that will be used during the extraction phase, so that when extraction occurs, the system already has pre-processed port information ready
2Reliability
If full layout versus schematic checking is performed on all cells, then complete verification is achieved, but the process takes a long time for modern designs with billions of electronic components
Solution Approach 1:
The verification process is segmented into two categories: cells with automatically detected ports that can be black-boxed (excluded from detailed extraction) and cells without ports that require full verification, allowing the system to focus computational resources only where necessary
Solution Approach 2:
The system performs partial verification by automatically black-boxing cells whose ports can be detected, accepting that some cells may be verified less thoroughly in exchange for dramatically reducing overall processing time, while still maintaining reliability for the critical path
3Adaptability or versatility
If layout designers want to perform physical verification frequently before layout completion, then design iteration is enabled, but the time-consuming black boxing process prevents frequent checking
Solution Approach 1:
The automated port detection system requires no manual setup or configuration by the layout designer - the tool automatically generates the cell port detection file from the existing layout and rule file, making the process as easy as running a standard verification command
Solution Approach 2:
The same automated cell port detection mechanism works for all verification scenarios whether the layout is complete or incomplete, allowing designers to perform black boxing at any stage of the design process without requiring different procedures
Data Source
AI summary
Text containers comprising information of cell ports are determined based on statements for cell ports in a rule file. Drawn layers comprising cell ports are determined based on the determined text containers or based on statements for attaching each of the test containers to a layout design layer in the rule file. Layout design layers connected to the drawn layers comprising cell ports are determined based on statements for connecting layout design layers in the rule file. A file for cell port detection is generated which associates each of the text containers comprising information of cell ports with one or more of the drawn layers comprising cell ports and one or more of the layout design layers connected to the one or more of the drawn layers comprising cell ports. The file for cell port detection can be used for extracting ports for cells to be black boxed.