Automated Wafer Sorting and Alignment With Laser Mark Reading
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Solution Overview
Problem
Current methods for sorting and aligning semiconductor wafers are manual and error-prone, leading to potential defects, especially with sensitive gallium nitride-coated wafers, and lack automation for recognizing holder status and laser markings, making the process inefficient and prone to errors.
Innovation Solution
An automated method and device that uses a robot arm with an optoelectronic sensor and end effector to detect and sort semiconductor wafers, align them, and read laser markings, eliminating manual handling and enabling fully automated operation, including recognition and storage of laser markings, suitable for wafers of different diameters and thicknesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual handling using vacuum tweezers is used for sorting and aligning wafers, then flexibility and adaptability are maintained, but the risk of defects, scratches, cracks, and breakage increases significantly
Solution Approach 1:
The patent replaces manual mechanical handling with an automated robot arm system that uses a specialized end effector. This mechanical system substitution eliminates human contact with wafer surfaces, preventing scratches and contamination while maintaining precise control over wafer manipulation throughout the sorting and alignment process.
Solution Approach 2:
The patent introduces an intermediary support element that cradles the wafer during transfer operations. This support element acts as a mediator between the robot arm and the wafer, providing stable support without direct contact with sensitive wafer surfaces, thereby preventing defects while enabling precise positioning.
2Loss of information
If manual reading and recording of laser markings is performed, then identification of wafers is achieved, but the process becomes time-consuming and error-prone
Solution Approach 1:
The patent replaces manual visual inspection and recording with an automated optoelectronic sensor system. This sensor system automatically detects, reads, and records laser markings on wafer edges, eliminating human error in data capture while significantly reducing the time required for identification processes.
Solution Approach 2:
The patent implements a self-identifying system where the optoelectronic sensor automatically captures and processes laser marking information without human intervention. The system self-corrects for reading errors and automatically records accurate wafer identification data, eliminating the need for manual verification and reducing processing time.
3Productivity
If automated handling with robot arm is implemented, then handling speed and consistency improve, but the system complexity and initial cost increase
Solution Approach 1:
The patent designs the robot arm system with a multi-functional end effector that can handle wafers of different diameters (150mm and 200mm) using the same basic mechanism. The support element and alignment features are universally applicable across different wafer sizes, reducing the need for multiple specialized tools and simplifying the overall system architecture.
Solution Approach 2:
The patent incorporates dynamic alignment features where the support element can adjust its position and orientation to accommodate different wafer sizes and orientations. This dynamic adaptability allows a single automated system to handle multiple wafer specifications, improving productivity without requiring separate dedicated systems for each wafer type.
4Temperature
If re-sorting into temperature-resistant holders is performed manually, then temperature requirements are met, but labor costs and processing time increase
Solution Approach 1:
The patent implements preliminary detection of holder temperature characteristics and automatic selection of appropriate holders before the wafer transfer process begins. The control system pre-configures the destination holder based on the wafer's temperature requirements, eliminating the need for manual selection and ensuring temperature requirements are met while maximizing processing efficiency.
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
The automated process ensures reliable, efficient, and gentle handling of semiconductor wafers, reducing defects and errors, increasing throughput, and allowing for the sorting and alignment of up to 160 wafers in 8 hours without human intervention.
Implementation Method 1
an optoelectronic sensor... to detect and sort semiconductor wafers
Implementation Method 2
the laser marking on the wafer edge must also be identified and recorded
Data Source
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AI summary
A method for sorting and aligning semiconductor wafers, comprising the following steps: detecting a first multi-wafer holder and its load status; removing a semiconductor wafer from the first holder; aligning the semiconductor wafer according to a predetermined orientation; detecting and reading a laser mark on the semiconductor wafer; storing the information contained in the laser mark in a database or storage medium; and sorting the oriented semiconductor wafer into a second multi-wafer holder; wherein these process steps are performed automatically. A device for sorting and aligning semiconductor wafers, comprising a chamber and a control unit (10), wherein the chamber includes the following units: a first fixation (8) for a first multi-wafer holder (9);a second fixing (8) for a second holder (9) for several semiconductor wafers; a robot arm (4) with an end effector (6) comprising a support element for receiving and transporting a semiconductor wafer and an optoelectronic sensor; a storage station (7) for a semiconductor wafer, configured such that the semiconductor wafer can be placed and removed by means of the end effector (6); a device (11) for aligning the semiconductor wafer by means of rotation; and a reader (12) for identifying a laser mark on the edge of the semiconductor wafer; wherein the control unit (10) is designed for automated control of the robot arm, and the optoelectronic sensor and the reader (12) are coupled to a database or a storage medium.