On-Tool Wafer OCR Verification for Q-Time Scrap Prevention
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Solution Overview
Problem
Existing methods for identifying semiconductor wafers in fabrication processes are inefficient, leading to long handling times and wafer scrap due to the need for manual verification of wafer IDs, which often exceed predetermined thresholds, resulting in out-of-specification or quench time events.
Innovation Solution
Integration of an Optical Character Recognition (OCR) system on wafer processing tools that can read wafer identification marks in real-time, allowing for immediate verification of wafer IDs using various light sources and positioning on the processing tool, enabling automatic mismatch detection and correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual verification of wafer IDs is performed by transporting wafers to different tools, then wafer ID mismatch can be detected, but handling time increases and wafer scrap occurs
Solution Approach 1:
The patent combines the wafer ID verification function with the existing processing tool by integrating an OCR device and controller directly into the processing tool. This allows the processing tool to perform both processing and verification functions, eliminating the need to transport wafers to separate verification tools, thus reducing handling time while maintaining verification accuracy
Solution Approach 2:
The processing tool performs self-verification of wafer IDs by incorporating the OCR reading device and controller within the same tool. The tool reads the wafer ID, compares it with the predetermined ID, and generates mismatch alarms independently without requiring external verification tools, thereby eliminating transport time and enabling immediate detection
2Productivity
If real-time OCR reading is implemented on processing tools, then wafer handling time is reduced, but device complexity increases
Solution Approach 1:
The processing tool is enhanced with multi-functionality by integrating the OCR reading device and controller that enable both wafer processing and wafer ID verification. This universal design allows a single tool to perform multiple functions (processing and verification), improving productivity without requiring separate dedicated verification equipment
Solution Approach 2:
The controller acts as an intermediary between the OCR reading device and the processing system. It receives the wafer ID from the OCR device, compares it with the predetermined ID, and triggers mismatch alarms or notifications. This intermediary component manages the complexity by centralizing the verification logic within the existing control architecture
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 solution reduces wafer scrap by enabling real-time identification and verification, preventing Q-time over events and ensuring accurate tracking and processing of wafers, thereby improving production control and quality assurance.
Implementation Method 1
a light source disposed on the processing tool and configured for illuminating the wafer
Data Source
AI summary
Apparatus and methods for determining wafer characters are disclosed. In one example, an apparatus is disclosed. The apparatus includes: a processing tool configured to process a semiconductor wafer; a device configured to read an optical character disposed on the semiconductor wafer while the semiconductor wafer is located at the apparatus for wafer fabrication; and a controller configured to determine whether the optical character matches a predetermined character corresponding to the semiconductor wafer based on the optical character read in real-time at the apparatus.