Integrated Circuit Image Storage via Metal Pixel Capacitive Coupling
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Solution Overview
Problem
Existing methods for permanently storing an image in integrated circuits are not compatible with industrial-scale manufacturing, as they require multiple masks and the image becomes inaccessible when the circuit is disabled, making it difficult to diagnose malfunctions.
Innovation Solution
A method involving pixels formed by metal portions of a semiconductor substrate with capacitive coupling elements, allowing image storage and retrieval even after the integrated circuit is manufactured and potentially disabled, using a simple and cost-effective process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ROM-type memory or EEPROM is used to permanently store an image in an integrated circuit, then the image can be stored permanently, but the image becomes inaccessible when the circuit is disabled and multiple specific masks are required for manufacturing
Solution Approach 1:
The patent extracts the image storage function from traditional ROM/EEPROM structures and implements it directly in the circuit layout using metal portions that form pixels visible on the circuit surface. This allows the image to be permanently stored as part of the circuit structure itself, remaining accessible even when the circuit is disabled, without requiring separate memory components or additional masks beyond the standard circuit masks.
Solution Approach 2:
The patent makes the circuit metal layers serve dual functions: both as functional circuit interconnects and as image storage medium. The metal portions that form the circuit traces also create the visible pixel patterns that constitute the stored image, eliminating the need for dedicated memory structures and allowing the same hardware to serve both operational and identification purposes.
2Reliability
If a ROM-type memory is used to store an image, then permanent storage is achieved, but the manufacturing complexity increases due to the need for at least one specific mask for memory cell connections
Solution Approach 1:
The patent merges the image storage function with the standard circuit manufacturing process by using the existing metal interconnect layers and patterning masks. The image is formed by selectively connecting or isolating metal portions using the same masks required for circuit fabrication, thereby combining two functions (circuit interconnection and image storage) into a single manufacturing process without adding extra masks or steps.
3Adaptability or versatility
If laser etching is used to store an image on each integrated circuit, then individual image storage is enabled, but the process is not compatible with industrial-scale manufacturing and images may be unavailable when etching is to be implemented
Solution Approach 1:
The patent performs preliminary action by pre-defining the image pattern in the circuit layout design before manufacturing. The metal portions are positioned and connected during the standard circuit fabrication process, so the image is already formed on the wafer before individual circuit separation. This eliminates the need for post-fabrication laser etching and allows industrial-scale manufacturing while maintaining individual image identification capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables permanent and accessible image storage at an industrial scale, allowing for easy reading of the image even when the integrated circuit is malfunctioning, simplifying the storage and retrieval process.
Implementation Method 1
for each pixel, a capacitive coupling element connecting the pixel to a selection element
Implementation Method 2
a voltage is applied between at least several pixels and the substrate, via the corresponding capacitive coupling element, to alter said insulating portion and electrically connect the first metal portion to the substrate
Data Source
AI summary
An integrated circuit including a substrate of a semiconductor material and first metal portions of a first metallization level or of a first via level defining pixels of an image. The pixels are distributed in first pixels, for each of which the first metal portion is connected to the substrate, and in second pixels, for each of which the first metal portion is separated from the substrate by at least one insulating portion.