On-Chip Crack Detector Circuit for Semiconductor Die BIST
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Solution Overview
Problem
Cracks in semiconductor dies or packages, particularly those made of low-k dielectric material, adversely affect electrical operation and reliability, necessitating accurate crack detection methods.
Innovation Solution
A crack detector unit (CDU) comprising a switching circuit, crack sensor, and logic circuit is used, which enables crack detection through a built-in-self-test (BIST) mechanism, utilizing MOSFETs and logic gates to identify cracks in semiconductor dies by analyzing current flow and digital states at detection pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional external testing methods are used to detect cracks, then crack detection can be performed, but additional test pads and external equipment are required, increasing device complexity and reducing layout efficiency
Solution Approach 1:
The patent combines the crack sensor, switching circuit, and logic circuit into a single integrated crack detector unit (CDU) that is built directly into the semiconductor die. This merging of detection functions eliminates the need for separate external test pads and equipment, thereby reducing device complexity while maintaining crack detection accuracy.
Solution Approach 2:
The CDU performs self-testing through built-in self-test (BIST) functionality, where the unit automatically detects cracks using its own integrated components. This self-service approach eliminates dependency on external testing equipment and additional test pads, simplifying the overall device structure while preserving measurement precision.
2Ease of operation
If built-in-self-test mechanism is implemented, then on-chip crack detection is achieved, but additional circuit components are required within the chip
Solution Approach 1:
The patent merges the crack sensor, switching circuit, and logic circuit into a single integrated CDU unit. This consolidation reduces the overall number of discrete components on the chip compared to having separate testing systems, while still providing complete on-chip crack detection functionality.
Solution Approach 2:
The CDU is designed to perform multiple functions: normal operation mode and crack detection mode. The same integrated unit serves both as part of the functional circuitry and as a detection system, eliminating the need for dedicated separate testing components and reducing overall device complexity.
3Area of stationary object
If crack detection is integrated into the semiconductor die, then layout efficiency is improved, but the detection mechanism requires switching circuits and logic gates
Solution Approach 1:
The patent integrates the crack sensor, switching circuit (PMOS transistor), and logic circuit (NAND and AND gates) into a single compact CDU unit that occupies minimal die area. This merging approach allows the detection functionality to be embedded within the existing chip layout without requiring separate dedicated spaces for testing components.
Solution Approach 2:
The CDU uses a PMOS transistor as a switching element that can be controlled through voltage parameter changes (VDD applied to gate). This allows the circuit to switch between normal operation mode and crack detection mode using standard voltage control, avoiding the need for complex additional control circuits and minimizing area requirements.
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
The CDU provides efficient, on-chip crack detection with clear digital outputs, allowing for precise identification of crack locations and enabling alarm and diagnosis without requiring additional test pads, enhancing layout efficiency and scalability.
Implementation Method 1
The crack sensor is configured to be electrically connected to the switching circuit, ground, and an operating voltage
Data Source
AI summary
The present disclosure provides a crack detection unit (CDU), a semiconductor die, and a method of detecting a crack of a semiconductor die. The CDU comprises a switching circuit, a crack sensor, and a logic circuit. The switching circuit is configured to enable the crack sensor. The crack sensor is configured to be electrically connected to the switching circuit, the ground, and an operating voltage. The logic circuit is configured to be electrically connected to the switching circuit and the crack sensor, wherein the CDU is enabled based on an input of the logic circuit. The output of the logic circuit indicates whether the crack sensor contains a crack.