Die Crack Detection Circuit With Relay-Driven Pulse Loop
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Solution Overview
Problem
Current methods for cutting silicon wafers, such as blade sawing and laser cutting, inevitably result in crack formation, which can destroy integrated circuits and lead to scrapped dies, necessitating a reliable method for detecting crack damage in semiconductor dies.
Innovation Solution
A circuit for detecting crack damage, comprising a test circuit, a crack detection loop, and a relay driving unit, where the test circuit outputs a pulse detection signal, and the relay driving unit amplifies and transmits this signal through the crack detection loop connected between the seal ring and the guard ring of the die, improving detection speed and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If blade sawing or laser cutting is used to cut the silicon wafer, then the silicon wafer can be divided into individual dies, but cracks are inevitably formed in the silicon wafer which may destroy integrated circuits
Solution Approach 1:
The patent applies preliminary action by implementing crack detection before the die is packaged and shipped. The detection circuit is built into the die structure itself, allowing crack detection to be performed early in the manufacturing process, before the die leaves the factory. This enables damaged dies to be identified and removed from the production stream before they can cause failures in the field.
Solution Approach 2:
The patent applies self-service by integrating the crack detection functionality directly into the die structure through dedicated detection circuits and loops. The die essentially detects its own cracks using built-in test circuits that generate test signals and evaluate the integrity of detection loops routed through seal rings and guard rings. This eliminates the need for external specialized testing equipment.
2Reliability
If a crack detection circuit is added to the die, then crack damage can be identified, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing the crack detection circuit to share infrastructure with the normal operating circuitry of the die. The detection loops are routed through existing seal rings and guard rings that are already part of the die structure. The detection circuits can coexist with functional circuits, and the same physical structures (metal layers, interconnects) serve both operational and detection purposes, reducing the need for completely separate dedicated detection infrastructure.
Solution Approach 2:
The patent applies copying by creating simplified test versions of the actual signal paths. The detection loops are essentially copies or replicas of the critical signal paths that would be affected by cracks, but designed specifically for testing purposes. These loops mirror the routing through seal rings and guard rings without requiring full duplication of the entire functional circuitry, allowing crack detection while minimizing added complexity.
3Measurement precision
If the pulse detection signal transmission capability is enhanced, then detection sensitivity improves, but the device complexity increases
Solution Approach 1:
The patent applies intermediary by introducing relay driving units as mediator components between the test signal source and the detection loops. These relay drivers act as intermediate stages that receive weak test signals from the detection circuits and amplify them to stronger levels suitable for reliable transmission through the detection loops and out to external testing equipment. This intermediary amplification stage enables sensitive crack detection without requiring the entire signal path to be designed for high-power transmission.
Data Source
AI summary
A circuit and method for detecting crack damage of a die are provided. The circuit comprises: a test circuit located within a seal ring of the die for outputting a pulse detection signal; a crack detection loop arranged outside a guard ring of an internal processing circuit of the die, having an input end connected to an output end of the test circuit and an output end connected to an output pin of the die; and a relay driving unit arranged between the input end and output end for increasing a capability of transmission of the pulse detection signal, wherein the seal ring surrounds the whole die; in a test mode, the test circuit outputs the pulse detection signal to the crack detection loop, and a test machine determines whether the die is damaged by a crack by reading a signal on the output pin of the die.