Spin-on Tool Optical Detector for Wafer Defect Inspection
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Solution Overview
Problem
Existing methods for detecting sectorial defect areas on semiconductor wafers during spin-on coating processes are inefficient and require manual, time-consuming visual inspection, which hampers production yields and is not effective in maintaining surface uniformity.
Innovation Solution
A method involving a spin-on tool with a rotatable platen and a fixed optical detector that impinges an incident light beam on the wafer to detect reflected light, allowing for non-contact measurement of film surface uniformity and effective detection of sectorial defects without removing the wafer from the spin coat system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual visual inspection is used to detect sectorial defect areas, then defect detection capability is provided, but inspection time is excessive and productivity is reduced
Solution Approach 1:
The patent replaces manual visual inspection with an automated optical inspection system that uses light sources and light receivers to detect defect areas. The system uses optical curtains and photo sensor arrays to automatically scan the wafer surface, eliminating the need for manual microscope inspection while maintaining defect detection capability and significantly improving inspection throughput.
Solution Approach 2:
The inspection system is integrated into the spin-on tool itself, allowing the wafer to be inspected automatically during or after the spin coating process without requiring removal to a separate inspection station. The system performs self-inspection as part of the manufacturing process, improving both productivity and workflow efficiency.
2Measurement precision
If complex inspection systems with multiple light sources and receivers are used, then defect detection capability is improved, but device complexity increases
Solution Approach 1:
The patent divides the inspection system into functional segments: a spin-on tool for material deposition, an optical inspection system with light sources and receivers, and a control system for coordinating operations. This segmentation allows each component to perform its specific function efficiently while reducing overall system complexity compared to integrated multi-functional systems.
Solution Approach 2:
The spin-on tool is designed to perform multiple functions: spin coating the photoresist material and subsequently holding the wafer for optical inspection. This multi-functionality eliminates the need for separate inspection equipment and reduces system complexity while maintaining defect detection capability through the integrated optical inspection system.
3Ease of operation
If wafer is removed from spin coat system for inspection, then inspection can be performed, but process continuity is interrupted and time is lost
Solution Approach 1:
The optical inspection system is prepared and positioned in advance within the spin-on tool, allowing immediate inspection of the wafer after spin coating without requiring removal to a separate inspection station. The system components (light sources, receivers, and control mechanisms) are pre-configured to enable seamless transition from coating to inspection.
Solution Approach 2:
The patent merges the spin coating function and optical inspection function into a single integrated system. The spin-on tool not only deposits the photoresist material but also holds and inspects the wafer using the optical inspection system, eliminating the need to remove the wafer for inspection and maintaining process continuity.
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 enhances detection efficiency and throughput by enabling on-line inspection of spin-on materials, reducing manual intervention and improving yield by identifying defects through light signal analysis, thus ensuring better surface uniformity and pattern transfer accuracy.
Implementation Method 1
spinning the wafer and scanning the spin coat material layer by impinging an incident light beam emanated from the fixed detector and detecting a reflected light beam
Data Source
AI summary
A method of fabricating semiconductor integrated circuits includes (1) providing a spin-on tool comprising a rotatable platen for holding and spinning a wafer disposed thereon, a fluid supply system for providing spin-on solution onto the wafer, and a detector fixed in a position above the wafer, wherein the wafer has a radius R; (2) spin-on coating the wafer by depositing the spin-on solution onto surface of the wafer from its center and spinning-off to leave a spin coat material layer; and (3) spinning the wafer and scanning the spin coat material layer by impinging an incident light beam emanated from the fixed detector and detecting a reflected light beam.