Compressed Chip ID Encoding for Semiconductor Marking Speed
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Solution Overview
Problem
The existing methods for marking semiconductor chips with information are time-consuming and inefficient, as they require writing a large number of characters including lot IDs, wafer numbers, and chip coordinates, which complicates the identification and analysis of semiconductor chips after packaging, making it difficult to determine defect causes.
Innovation Solution
A chip information character set generation system that codes conventional lot IDs, wafer numbers, and chip coordinates using a decimal or 62 decimal numeration system to reduce the number of characters, allowing for faster marking on the rear face of chips, with the generated IDs and coordinates being written using a combination of numerals and alphabetical letters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If conventional chip information character sets (lot ID, wafer number, chip coordinates) are written on the rear face of chips, then complete identification information is recorded, but the marking process becomes time-consuming and reduces productivity
Solution Approach 1:
The patent changes the parameter of character encoding by introducing a compressed 62-character set (0-9, A-Z, a-z) instead of conventional longer representations. This encoding scheme reduces the number of characters needed to represent the same information, directly decreasing marking time while preserving all necessary chip identification data.
Solution Approach 2:
The chip information is segmented into distinct components (lot ID, wafer number, chip coordinates) and encoded separately using the compressed character set. This segmentation allows for efficient encoding of each component and facilitates later decoding and analysis of specific information elements.
2Reliability
If detailed chip information (lot ID, wafer number, coordinates) is marked on chips, then traceability is improved, but the complexity of the character set increases marking time
Solution Approach 1:
The patent transforms the parameter of information density by using a compressed 62-character encoding system. This allows detailed traceability information (lot ID, wafer number, chip coordinates) to be represented in fewer characters, reducing marking time while maintaining complete traceability capability through the encoded character set.
3Difficulty of detecting and measuring
If a comprehensive chip information character set is used, then defect analysis capability is enhanced, but the marking process becomes more complex and slower
Solution Approach 1:
The patent changes the parameter of encoding efficiency by implementing a compressed 62-character set that reduces the number of characters needed to represent comprehensive chip information. This simplifies the marking process while preserving all necessary data for defect analysis, including lot ID, wafer number, and chip coordinates.
Data Source
AI summary
A chip information character set including a lot ID for chip-marking, which has a smaller number of characters than that of a conventional lot ID used in a fabrication line for a semiconductor device, is generated by coding the conventional lot ID using a decimal numeration system or a 62 decimal numeration system. A wafer identifier for chip-marking having 1-character is generated by coding a conventional number of a wafer using a set of identification symbols. A chip coordinate for chip-marking is having either 1-character or 2-characters is generated by coding a conventional coordinate of a chip in the wafer using the decimal or 62 decimal numeration system. The chip information character set has a simplified form to be written in a relatively short time, thereby increasing a productivity of the semiconductor device.