Embedded Conductive Structure for Passivation Integrity Testing
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Solution Overview
Problem
Current methods for testing the integrity of semiconductor device passivation layers, such as optical inspection and chemical tests, are inadequate in detecting defects like pinholes and cracks, especially in organic layers like polyimide, and cannot determine if defects have penetrated the layer.
Innovation Solution
A method involving a structured layer of electrically conducting material with bands connected to contacts is deposited on the semiconductor device, followed by a passivation layer and additional electrically conducting material, allowing resistance measurement between contacts to assess the passivation layer's integrity, with optional insulating layers for enhanced sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If optical inspection using a microscope is used to detect defects in the passivation layer, then the inspection process is simple and non-destructive, but it cannot determine whether a defect has penetrated the passivation layer and nearly impossible to detect pin holes
Solution Approach 1:
The patent introduces an electrically conducting material as an intermediary substance that is deposited onto the passivation layer. This conducting material serves as a mediator that reveals defects (especially pinholes) through electrical resistance measurements, enabling detection capabilities that optical inspection cannot achieve while maintaining process simplicity.
Solution Approach 2:
The patent replaces the optical inspection mechanism with an electrical measurement mechanism. Instead of using light and microscopes to detect defects, the system uses electrical resistance measurements through deposited conducting material, fundamentally changing the detection principle from optical to electrical while improving defect detection capability.
2Measurement precision
If chemical tests such as the orthophosphoric acid test are used to determine passivation layer integrity, then the test can reveal some defects, but it does not reveal all defects and cannot be used with organic passivation layers made of polyimide since the acid consumes the polyimide
Solution Approach 1:
The patent changes the fundamental parameter of the test from chemical (acid-based) to physical (electrical resistance measurement). This parameter change allows the test to be universally applicable to all passivation layer materials including organic polyimide layers, eliminating the material compatibility limitations of chemical tests while maintaining high defect detection precision.
Solution Approach 2:
The patent uses a disposable layer of electrically conducting material that is deposited onto the passivation layer for testing purposes. This conducting material layer serves as a consumable test medium that enables universal testing without damaging the underlying passivation layer, replacing the destructive chemical acid test with a non-destructive electrical test using a sacrificial conducting layer.
3Measurement precision
If a structured layer of electrically conducting material is deposited onto the substrate and resistance measurement is performed, then all defects including pinholes can be reliably detected, but the device complexity increases due to additional deposition steps and measurement circuitry
Solution Approach 1:
The patent designs the structured layer of electrically conducting material with a dual function: it serves as both the test medium for defect detection and as a functional component of the semiconductor device. This multi-functionality reduces the need for separate test structures and minimizes additional complexity while maintaining high defect detection precision.
Solution Approach 2:
The patent enables the semiconductor device to perform its own integrity testing through the embedded structured conducting layer and resistance measurement capability. The device structure itself provides the means for self-diagnosis of passivation layer integrity, eliminating the need for external complex testing equipment and reducing overall system complexity.
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
This approach effectively detects defects in the passivation layer, including pinholes, and provides a reliable indication of its integrity, ensuring the semiconductor device's proper operation by setting a resistance threshold for acceptable integrity.
Implementation Method 1
A structured layer of electrically conducting material is deposited onto at least a portion of a top surface of a substrate of the semiconductor device... A passivation layer is deposited onto the at least a portion of the top surface of the substrate and the structured layer
Implementation Method 2
a resistance is measured between the at least two contacts. An indication with respect to integrity of the passivation layer is determined in dependence upon the measured resistance
Data Source
AI summary
The present invention relates to a method and system for testing integrity of a passivation layer (108) covering a semiconductor device. A structured layer of electrically conducting material (104) is deposited onto at least a portion of a top surface of a substrate (102) of the semiconductor device. The structured layer (104) comprises a plurality of bands (104.1, 104.2) connected to at least two contacts (106.1, 106.2) and disposed on the at least a portion of the top surface such that one of consecutive bands (104.1, 104.2) and consecutive portions of the bands (104.1, 104.2) are connected to different contacts (106.1, 106.2). A passivation layer (108) is deposited onto the at least a portion of the top surface of the substrate (102) and the structured layer (104) such that material of the passivation layer(108) is disposed between the bands of conducting material (104.1, 104.2) and on top of the structured layer (104). Electrically conducting material is then deposited onto the passivation layer (108) and a resistance is measured between the at least two contacts (106.1, 106.2). An indication with respect to integrity of the passivation layer (108) is determined in dependence upon the measured resistance.