Open Circuit Failure Point Localization in Semiconductor Test Structures
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Solution Overview
Problem
Existing methods for locating open circuit failure points in semiconductor test structures, particularly large-area structures, face challenges with Passive Voltage Contrast (PVC) and Active Voltage Contrast (AVC) tests, as they either fail to produce a bright-dark junction or require cumbersome counting methods, making accurate localization difficult.
Innovation Solution
The method involves performing two Active Voltage Contrast tests on a test structure with a metal diffusion blocking layer, creating scratch marks and forming a coating mark adjacent to the open circuit point, allowing for precise localization using the coating mark as a reference in subsequent tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Passive Voltage Contrast (PVC) test is used to locate open circuit failure point, then the test can be performed on grounded and floating structures, but it fails to produce a bright-dark junction in large-area test structures, making accurate localization difficult
Solution Approach 1:
The method applies preliminary action by performing a first Active Voltage Contrast test before the main localization step. This first test creates a scratch mark at a position adjacent to the open circuit failure point, which serves as a reference marker for subsequent localization steps, ensuring accurate positioning even in large-area structures where direct bright-dark junction visibility fails
Solution Approach 2:
The scratch mark acts as an intermediary element between the invisible open circuit failure point and the observable test structure surface. By creating this physical marker at a known relative position to the failure point, the method bridges the gap between the undetectable electrical defect and the observable physical structure, enabling precise localization through the coating mark reference system
2Reliability
If Active Voltage Contrast (AVC) test is used to locate open circuit failure point, then a bright-dark junction can be produced, but it requires cumbersome counting methods and cannot provide direct visual localization in large-area test structures
Solution Approach 1:
The first AVC test performs preliminary action by creating a scratch mark that serves as a permanent reference marker. This eliminates the need for repeated counting operations, as the scratch mark provides a direct visual reference point that can be located in subsequent steps without complex counting procedures
Solution Approach 2:
The scratch mark creates a physical copy or replica of the open circuit failure point's location on the test structure surface. This tangible marker can be observed and referenced directly, replacing the need for complex counting methods and providing a direct visual indication of the failure point's position relative to observable structure features
3Stability of the object's composition
If no reference mark is created during testing, then the test structure remains intact, but the open circuit point position cannot be accurately determined after testing
Solution Approach 1:
The method applies preliminary action by creating the scratch mark reference during the first AVC test, before the structure is subjected to further processing or analysis. This ensures the reference information is captured while the structure is still in its test configuration, preventing loss of position information in subsequent steps
Solution Approach 2:
The scratch mark serves as an intermediary that preserves the open circuit point position information in a form that can be observed and referenced after testing. Rather than directly marking the failure point (which might damage the structure), the scratch mark provides indirect but sufficient reference information that maintains structure integrity while preventing information loss
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 enables accurate and precise localization of open circuit points in large-area test structures, overcoming the limitations of existing methods by utilizing the coating mark to determine the relative position of the open circuit point, facilitating accurate slicing and analysis.
Implementation Method 1
By scanning the floating structure 201 with an electron beam 202
Implementation Method 2
the surface of the floating structure 201 will accumulate positive charges
Implementation Method 3
which will affect the moving trajectory of secondary electrons escaping from the surface of the sample, thus affecting the number of secondary electrons collected by an SEM detector
Implementation Method 4
the upper layer structure further including a metal diffusion blocking layer, the metal diffusion blocking layer covering surfaces of the second metal layer patterns and the upper interlayer film
Data Source
AI summary
The present application discloses a method for locating an open circuit failure point of a test structure, which includes the following steps: step 1: providing a sample formed with a test structure, a first metal layer pattern and a second metal layer pattern of the test structure forming a series resistor structure through each via; step 2: performing a first active voltage contrast test to the sample to show an open circuit point and making a first scratch mark at an adjacent position of the open circuit point; step 3: forming a coating mark at the first scratch mark on the sample; step 4: performing a second active voltage contrast test to the sample to show the open circuit point and locating a relative position of the open circuit point by using a position of the coating mark as a reference position.