Wafer Sample Preparation via Guided Splitting Points
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Solution Overview
Problem
Current methods for preparing cross-section samples in wafer level failure analysis face challenges with limited precision and high costs, particularly for samples with structures greater than or equal to 10 micrometers, and can damage photoresist with poor hardness, affecting subsequent analysis.
Innovation Solution
A method involving the formation of straight-line splitting points on a selected region of the sample, allowing for accurate and cost-effective sample preparation without damaging the sample, using an automated hardness tester to create uniform splitting points that guide a flat splitting interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If manual splitting method is used to prepare cross-section samples, then costs are reduced, but manufacturing precision deteriorates due to limited precision of manual splitting
Solution Approach 1:
The method applies preliminary action by forming multiple splitting points on the sample surface before performing the actual splitting operation. These pre-formed splitting points serve as guides that enable subsequent manual splitting to achieve higher precision while maintaining cost-effectiveness. The splitting points are created using a hardness tester that applies localized force to create indentation marks that define the exact splitting path.
2Manufacturing precision
If focused ion beam analyzer and grinding-polishing device are used to improve splitting precision, then manufacturing precision is improved, but costs increase significantly
Solution Approach 1:
The invention replaces expensive, complex equipment (focused ion beam analyzer and grinding-polishing device) with a simple, low-cost hardness tester and manual splitting tools. The hardness tester creates disposable splitting points that guide the splitting process, eliminating the need for costly equipment while achieving comparable or sufficient precision for the analysis needs.
Solution Approach 2:
The method substitutes complex mechanical systems (automated ion beam equipment and precision grinding machines) with a simpler mechanical approach using a hardness tester and manual splitting. The hardness tester uses localized mechanical force to create splitting points, and manual tools complete the splitting, replacing expensive automated systems with affordable manual processes.
3Productivity
If conventional sample preparation is performed on samples with photoresist, then sample preparation is completed, but the photoresist with poor hardness is deformed, causing harmful effects on subsequent analysis
Solution Approach 1:
The method applies preliminary action by forming splitting points on the photoresist surface before splitting. The hardness tester creates shallow indentation marks that define the splitting path without removing or deforming the photoresist. This preliminary marking step enables subsequent splitting to proceed along the marked path while preserving the photoresist integrity for subsequent analysis.
Data Source
AI summary
Embodiments of the present application provide a method for preparing a sample for wafer level failure analysis. The method includes that: a plurality of splitting points are formed on a surface of a selected region of a to-be-analyzed sample along a preset direction, the plurality of splitting points being arranged in a straight line; and the to-be-analyzed sample is split by taking the straight line where the plurality of splitting points are located as a splitting line, to expose a cross section of a side surface of the to-be-analyzed sample and form the sample for the wafer level failure analysis.