Copper Hillock Detection via Voltage Stress Testkey
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Solution Overview
Problem
Copper hillocks in integrated circuit production can confuse defect inspection tools, making it difficult to accurately detect other defects and estimate a suitable process window, thus affecting device quality and yield.
Innovation Solution
A method involving a testkey structure with a lower metallization layer, an upper metallization layer, and a dielectric layer, where a force voltage difference is applied under specific temperature and stress conditions to detect copper hillocks by sensing voltage differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional defect inspection tools are used, then general defect detection is performed, but copper hillocks confuse the tools and prevent accurate detection of other defects
Solution Approach 1:
The patent extracts the copper hillock detection function from the general defect inspection process by introducing a dedicated testkey structure. This separate structure allows copper hillocks to be detected independently before they interfere with the main defect inspection tools, thereby resolving the contradiction between general defect detection and copper hillock interference.
Solution Approach 2:
The testkey structure serves as an intermediary element between the copper interconnect layers and the defect inspection system. By applying voltage stress through this intermediary structure, copper hillocks are induced and detected in a controlled manner, preventing them from confusing the main defect inspection tools while maintaining accurate detection capability.
2Reliability
If a testkey structure with voltage stress is used, then copper hillock detection is enabled, but additional testing steps and complexity are introduced
Solution Approach 1:
The patent segments the testing function by creating a dedicated testkey structure separate from the main circuit. This segmentation allows copper hillock detection to be performed independently through voltage stress application, improving reliability without requiring complex modifications to the entire production testing system.
Solution Approach 2:
The testkey structure is designed to serve multiple functions: it acts as both a test structure for copper hillock detection and integrates with the existing metallization layers. By applying voltage stress through this universal structure, the patent achieves reliable copper hillock detection while minimizing additional complexity through multi-functionality.
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 method effectively detects copper hillocks, allowing for improved monitoring of the production process and estimation of a suitable process window, thereby enhancing device quality and yield.
Implementation Method 1
A force voltage difference is applied to the lower metallization layer and the upper metallization layer under a test temperature and stress time
Implementation Method 2
A changed sensing voltage difference to the lower metallization layer and the upper metallization layer is detected for detecting copper hillock
Data Source
AI summary
A method of copper hillock detecting includes the following steps. A testkey structure is disposed on a substrate, wherein the testkey structure includes a lower metallization layer, an upper metallization layer, and a dielectric layer between the lower metallization layer and the upper metallization layer. A force voltage difference is applied to the lower metallization layer and the upper metallization layer under a test temperature and stress time. A changed sensing voltage difference to the lower metallization layer and the upper metallization layer is detected for detecting copper hillock.