Wafer Tape Alignment Hole Sensing for Precise Wafer Centering
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Solution Overview
Problem
Manual centering of semiconductor wafers on tape for precise alignment during manufacturing is imprecise, leading to lower yield and higher costs due to improper cutting.
Innovation Solution
Utilizing alignment holes in the wafer tape and a light detection system to ensure precise centering of semiconductor wafers by observing light transmission through these holes, allowing for automatic adjustment to achieve accurate alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual centering is used to position the semiconductor wafer on the tape, then the operation is simple and quick, but the alignment precision is insufficient leading to improper cutting
Solution Approach 1:
The patent introduces alignment holes as an intermediary element between the wafer and the positioning system. These holes serve as reference markers that enable precise alignment detection without requiring complex direct measurement systems. The alignment holes translate the complex task of wafer centering into a simpler visual or optical detection task.
Solution Approach 2:
The patent replaces manual mechanical centering operations with an optical detection system. Instead of relying on operators to visually estimate and manually adjust wafer position, the system uses light transmission through alignment holes detected by sensors to automatically determine and correct wafer positioning, substituting mechanical adjustment with optical measurement and automated control.
2Productivity
If manual centering estimation is used, then the process is fast, but the yield decreases due to imprecise cutting
Solution Approach 1:
The patent implements preliminary alignment marking by creating alignment holes in the tape before wafer placement. This preliminary action establishes reference points that guide subsequent wafer positioning, eliminating the need for time-consuming trial-and-adjustment centering operations and ensuring consistent alignment precision across all wafers.
Solution Approach 2:
The patent incorporates a feedback mechanism where the optical detection system monitors light transmission through alignment holes and provides information about wafer positioning accuracy. This feedback enables real-time detection and correction of alignment deviations, ensuring high cutting precision while minimizing adjustment time through automated rather than manual iterative correction.
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 precise control over manufacturing processes such as dicing, pick and place operations, and inspection, reducing manufacturing errors and costs by ensuring proper wafer alignment.
Implementation Method 1
a light detection system to ensure precise centering of semiconductor wafers by observing light transmission through these holes
Data Source
AI summary
A semiconductor manufacturing equipment has a wafer tape including a plurality of alignment holes formed through the wafer tape. A semiconductor wafer is disposed over the wafer tape. The semiconductor wafer includes a circular or rectangular form-factor. A light source is disposed under the wafer tape. The semiconductor wafer is misaligned on the wafer tape with light passing through one or more alignment holes. The semiconductor wafer is centered on the wafer tape with no light passing through one or more alignment holes. The wafer tape has a plurality of wafer alignment markings for different size semiconductor wafers. A light detector is disposed over the semiconductor wafer to detect light passing through the wafer tape. A control arm can be attached to the semiconductor wafer to provide the ability to move the semiconductor wafer in response to a control signal from the light detector.