Stocker Wafer Sorting with Aligner and Dual Robots
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor manufacturing, existing stockers face difficulties in sorting wafers received in cassettes according to a predetermined reference, making it challenging to efficiently store and retrieve wafers.
Innovation Solution
A stocker system comprising a load port, an aligner for wafer alignment and identification, a first transfer robot for moving wafers between the load port and aligner, and a second transfer robot for moving wafers between the aligner and shelves, with a controller managing operations based on identification codes and teaching marks to ensure precise sorting and storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wafers are stored in cassettes on shelves without alignment and identification, then storage capacity is maximized, but the ability to sort wafers according to predetermined reference is lost
Solution Approach 1:
The stocker system is divided into functional modules: storage shelves for capacity, an aligner module with rotating members for orientation, and identification units with sensors for recognition. This segmentation allows each module to perform its specific function efficiently while working together to achieve wafer sorting capability without requiring complete system redesign.
Solution Approach 2:
The aligner acts as an intermediary between the storage shelves and the identification/delivery system. It receives wafers from shelves, aligns them to proper orientation, and presents them to the identification unit. This intermediary function enables the system to maintain high storage capacity while adding sorting capability through a dedicated alignment stage.
2Manufacturing precision
If an aligner with rotating members and centering mechanisms is added to enable wafer alignment and identification, then wafer sorting according to predetermined reference becomes possible, but device complexity increases
Solution Approach 1:
The aligner uses a rotating member with a curved or spherical surface to hold and orient wafers. This curved surface naturally guides the wafer into the correct orientation through rotation, achieving precise alignment without requiring complex mechanical positioning mechanisms. The spherical geometry simplifies the alignment process while maintaining high precision.
Solution Approach 2:
The aligner mechanism is designed to automatically orient wafers using the rotating member's geometry and gravity. The wafer placement on the rotating member and the subsequent rotation automatically aligns the wafer without requiring external intervention or complex control systems, enabling self-aligning functionality that reduces overall system complexity.
3Reliability
If teaching marks and sensors are added to enable precise positioning and collision detection, then operational safety and accuracy improve, but device complexity increases
Solution Approach 1:
Teaching marks with distinct visual characteristics (such as contrasting colors or patterns) are placed on the shelves. Optical sensors detect these marks to determine precise shelf positions and wafer orientations. The visual contrast enables reliable detection without requiring complex sensing mechanisms, achieving high positioning accuracy through simple optical recognition.
Solution Approach 2:
The teaching marks serve as optical copies or representations of shelf positions and orientations. Instead of using complex mechanical position sensors, the system uses visual marks that can be easily detected by optical sensors, creating a simplified sensing system that maintains high positioning accuracy through optical field copying of position information.
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 efficient sorting and storage of wafers according to a predetermined reference, preventing collisions and ensuring accurate placement, thereby improving operational efficiency and safety in the stocker system.
Implementation Method 1
a first sensor mounted on the second transfer robot, the first sensor configured to be positioned below the reflector, and irradiate light toward the reflector to detect the light reflected by the reflector
Data Source
AI summary
A stocker may include a load port which a cassette for receiving wafers is either loaded on or unloaded from, an aligner configured to align the wafers and to confirm identification codes of the wafers, a plurality of shelves each having slots for receiving the wafers, a first transfer robot having a first robot arm for transferring the wafers between the load port and the aligner and a second transfer robot having a second robot arm for transferring the wafers between the aligner and the shelves.