Wafer Chuck Attraction Control for Through Hole Substrates
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Solution Overview
Problem
Conventional semiconductor exposure apparatuses face issues with throughput and reliability when processing substrates with through holes, due to insufficient attracting force and vacuum pressure variations caused by leakage, especially when the attracting units overlap with the through holes.
Innovation Solution
A processing apparatus with a configuration that includes three pins and a control unit to manage the attraction and transfer of wafers, using suction means with a suction pump, opening and closing valves, and pressure gauges, and selecting control profiles based on the presence and position of through holes to optimize the attracting force and prevent overlap, thereby ensuring stable wafer transfer and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional vacuum attraction is used on substrates with through holes, then the attraction mechanism can hold substrates without through holes, but the attracting force becomes insufficient when through holes overlap with attracting units
Solution Approach 1:
The attracting unit is divided into multiple independent attraction holes (first, second, and third attraction holes) instead of using a single continuous vacuum region. This segmentation allows selective activation of specific attraction holes based on the presence and position of through holes, preventing vacuum leakage while maintaining adequate holding force on substrates with through holes.
Solution Approach 2:
The system dynamically adjusts which attraction holes are activated based on real-time detection of through hole positions. The control unit selectively turns on or off specific attraction holes depending on whether they would overlap with through holes, making the attraction system adaptive to different substrate configurations and maintaining reliability across varying conditions.
2Productivity
If vacuum attraction is applied to substrates with through holes, then substrate transfer can be performed, but vacuum pressure varies due to leakage causing attraction abnormalities
Solution Approach 1:
By segmenting the attraction system into multiple independent holes with individual control, the patent prevents vacuum leakage from propagating through the entire attraction region. When a through hole is detected, only the specific overlapping attraction hole is deactivated, while others remain active, maintaining stable vacuum pressure and consistent attraction force.
Solution Approach 2:
The system uses detection means to identify through hole positions and provides feedback to the control unit, which then adjusts the activation state of individual attraction holes accordingly. This closed-loop feedback mechanism ensures that attraction stability is maintained by preventing leakage at problematic locations while preserving productivity through automated adaptation.
3Manufacturing precision
If attracting units are positioned to hold wafers effectively, then wafer transfer precision is improved, but attraction abnormalities occur when through holes and attracting units overlap
Solution Approach 1:
The system dynamically reconfigures which attraction holes are active based on through hole detection, allowing the attraction pattern to adapt to substrate variations. This dynamic adjustment maintains wafer transfer precision by ensuring adequate attraction at non-overlapping regions while preventing processing interruptions caused by vacuum leakage at overlapping regions.
Solution Approach 2:
Different attraction holes are selectively activated or deactivated based on local substrate conditions (presence or absence of through holes at specific positions). This local quality approach ensures that each region of the substrate receives appropriate attraction treatment, maintaining overall transfer precision while avoiding abnormalities at problematic locations.
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 solution enhances throughput and reliability by preventing the discontinuation of processing sequences, maintaining sufficient attracting force, and reducing the risk of damage and positional shifts during wafer transfer, even when through holes and attracting holes overlap.
Implementation Method 1
The wafer stage 6 vacuum-attracts the wafer 9
Implementation Method 2
The wafer stage transfer robot holds the wafer by using vacuum pressure and transfers it
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2E
AI summary
A processing apparatus that performs processing to a wafer (9) is provided, the processing apparatus comprising a wafer chuck (8) disposed on a stage (6) and that holds the wafer (9); three pins (11a, 11b, and 11c) that attract the wafer (9) and move the wafer (9) from the wafer chuck (8); and a control unit (15) that is configured to stop or decrease the attraction of the three pins (11a, 11b, and 11c) based on information about a through hole (26) of the wafer (9) when the wafer (9) is moved from the wafer chuck (8) by the three pins (11a, 11b, and 11c).