Test Key Structure with Snake-Shaped Conductive Layer for Crack Detection
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Solution Overview
Problem
The shrinking size of conductive pads in semiconductor devices leads to increased stress and potential damage during manufacturing, which is difficult to detect, causing cracks that can disrupt circuit layers and affect device performance.
Innovation Solution
A test key structure with adjacent conductive pads and a snake-shaped test conductive layer is introduced, allowing for real-time detection of cracks by disrupting the circuit when they occur, simulating the conditions in the device region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the size of conductive pads is reduced to increase component density, then the component density is improved, but the stress concentration increases and cracks are more easily generated
Solution Approach 1:
The invention introduces a test key structure with multiple conductive pads arranged in a specific pattern, separating the testing function from the device region. This segmentation allows the test structure to bear the stress of crack detection while the device region maintains high density without additional testing overhead.
Solution Approach 2:
The test key structure is designed as a copy of the actual device structure, with conductive pads and underlying layers replicated in the test region. This copying enables the test structure to simulate the same stress conditions and crack generation mechanisms as the device region, allowing indirect detection of process quality.
2Quantity of substance
If the size of conductive pads is reduced, then the component density is improved, but the detection difficulty of cracks increases
Solution Approach 1:
The invention introduces an intermediary test key structure that acts as a mediator between the manufacturing process and the detection system. The test structure with its larger, more visible cracks serves as an intermediary that translates the subtle process variations into detectable signals, making crack detection feasible without directly inspecting the tiny device region pads.
Solution Approach 2:
By creating a copy of the device structure in the test region, the invention amplifies the detectability of cracks while maintaining the same process conditions. The test structure's cracks are more easily detected than those in the device region, yet they reflect the same manufacturing quality.
3Ease of manufacture
If general semiconductor manufacturing process is used, then the manufacturing simplicity is maintained, but the crack detection capability is insufficient
Solution Approach 1:
The invention merges the test structure formation with the existing device manufacturing process. The test key structure is formed using the same process steps as the device region, combining the testing functionality with the manufacturing flow without requiring separate processing stages, thus maintaining manufacturing simplicity while enhancing detection capability.
Solution Approach 2:
The test key structure is formed preliminarily during the manufacturing process, before final device assembly. This preliminary action of creating the test structure allows for subsequent detection of cracks that may have formed during manufacturing, enabling quality assessment before the device is completed and shipped.
Data Source
AI summary
The invention provides a test key structure, which comprises two conductive pads arranged adjacent to each other, a first space is between the two conductive pads, two vertical contact plugs respectively located below the two conductive pads and electrically connected with the two conductive pads, and a test conductive layer located below and electrically connected with the two vertical contact plugs, when views from a top view, the test conductive layer presents a snake-shaped arrangement pattern.