Semiconductor Wafer Defect Marking via Mechanical Indentation
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Solution Overview
Problem
Existing methods for marking small defects on semiconductor wafers are prone to causing contamination or damage, and existing marking techniques, such as laser-induced markings, result in inaccuracies and cross-contamination, making it difficult to accurately locate defects for further analysis.
Innovation Solution
A method and device for marking defects on semiconductor wafers using a predefined pattern of reference markings with specific depth and opening angle, applied using an indentation tool, which allows for precise localization of defects without additional contamination or damage, utilizing an atomic force microscope for image generation and processing to achieve precise defect positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser-induced markings are used to mark defects on semiconductor wafers, then defects can be located for further analysis, but contamination and damage are caused to the wafer surface
Solution Approach 1:
The patent replaces the optical laser marking system with a mechanical indentation system. A hard tip (diamond or carbide) physically indents the wafer surface to create markings, eliminating the harmful thermal and radiation effects of laser while achieving permanent, contamination-free marks for defect location
Solution Approach 2:
The patent introduces an intermediary mechanical indentation tool that transfers the defect location information from the optical detection system to the physical wafer surface without direct contact between the detection system and wafer, preventing contamination while maintaining marking capability
2Reliability
If conventional marking methods are used on small defects, then defects can be identified, but the marking process causes additional contamination
Solution Approach 1:
The patent replaces chemical and optical marking methods with pure mechanical indentation using a hard tip, creating physical marks that do not introduce chemical contamination or require additional processing steps that could cause cross-contamination
Solution Approach 2:
The indentation markings are created directly on the wafer surface during the inspection process itself, using the same system, eliminating the need for separate marking operations that could introduce contamination
3Ease of operation
If laser marking is applied to locate defects, then subsequent analysis can be performed, but inaccuracies in positioning occur
Solution Approach 1:
The patent uses mechanical indentation to create precise, permanent physical marks that maintain accurate spatial relationship with the detected defect, enabling precise relocation during subsequent analysis without the positioning drift or inaccuracy associated with optical laser marking
Solution Approach 2:
The patent performs the marking action immediately after defect detection, while the defect position is still known and recorded, ensuring the marking is placed with maximum accuracy before any potential drift or loss of positioning information can occur
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
Enables accurate and contamination-free marking of small defects on semiconductor wafers, allowing for precise defect analysis without cross-contamination or damage, improving the reliability of subsequent measurement processes.
Implementation Method 1
the generation of the first image is carried out using an atomic force microscope (AFM)
Implementation Method 2
marking the semiconductor wafer with a plurality of reference markings with a depth d and an opening angle α in one predefined pattern
Data Source
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AI summary
A method for marking defects on the surface of a semiconductor wafer, comprising the following steps: identifying a marker location on the surface of a semiconductor wafer and marking a surface of the semiconductor wafer with a plurality of reference markers having a depth d and an opening angle α in a predefined pattern around the marker location using a marking tool, wherein the marker location corresponds to a position of a defect on the surface of the semiconductor wafer and the identification of the marker location includes providing a defect file containing a list of approximate positions of a plurality of defects on the semiconductor wafer and moving a lens to an approximate position of a defect for microscopic analysis.wherein the microscopic analysis comprises the steps (1) generating a first image and (2) analyzing the first image using electronic image processing methods, with the aim of obtaining a more accurate position of the defect, wherein the generation of the first image is carried out using an atomic force microscope (AFM).