Laser Scanner Wafer Alignment for Stacked Wafer Center Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current wafer alignment methods require multiple sensors and are inefficient for aligning multiple wafers stacked vertically, leading to increased time and error in center alignment due to the need for separate light receiving and emitting units and limitations in interface management and electrical design.

Innovation Solution

A method and apparatus using a single laser scanner to irradiate wafers from the rear or lower side, obtaining images to calculate the center point of wafers by detecting at least three wafer edges and determining if the calculated center is within a preset tolerance range, allowing for simultaneous alignment of multiple wafers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a light receiving unit and a light emitting unit are installed for each wafer to align multiple wafers, then wafer alignment can be performed, but the number of sensors increases and interface management becomes complex

Engineering Contradiction:

Improvewafer center alignment accuracyVSAvoidnumber of sensors and interface management

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

A single laser scanner is designed to perform multiple functions: it can detect edges of multiple wafers simultaneously and determine their relative positions. The laser scanner serves as a universal detection device that replaces multiple separate light receiving and emitting units, thereby reducing sensor quantity while maintaining alignment capability for stacked wafers

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the light emitting and light receiving functions into a single integrated laser scanner unit. By merging these previously separate components into one device, the system reduces the total number of sensors needed while maintaining the ability to perform wafer edge detection and center alignment for multiple wafers

Inventive Principle:

Principle #5Merging (Combining)

2Ease of operation

If two hands are used to move wafers between light receiving and emitting units, then wafer transfer can be performed, but one hand must be left out during alignment and two-hand positioning cannot be performed simultaneously

Engineering Contradiction:

Improvewafer transfer operationVSAvoidcenter alignment accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical two-hand positioning system with an optical detection system. The laser scanner optically detects wafer edges and calculates center positions, eliminating the need for mechanical hand positioning during alignment. This substitution allows continuous two-hand operation for wafer transfer while maintaining high alignment precision through optical measurement

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If die-to-die comparison method is used to align wafers, then center alignment can be achieved, but the inspection time increases significantly

Engineering Contradiction:

Improvewafer center alignment accuracyVSAvoidwafer inspection speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent extracts only the essential information needed for alignment (wafer edge positions) and processes it directly to calculate center points. By taking out only the necessary edge detection function and eliminating unnecessary comparison steps, the system achieves fast alignment without the time-consuming die-to-die comparison process

Inventive Principle:

Principle #2Taking out (Extraction)

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 approach simplifies the alignment process by reducing the number of sensors needed and improving accuracy, enabling faster and more efficient center alignment of multiple wafers, thereby reducing the time required for wafer inspection.

Implementation Method 1

a laser irradiation operation of irradiating a laser toward the wafer using a laser scanner disposed on a rear side or a lower side of the wafer and obtaining an image

Methodology Applied

Scientific EffectLaser: Laser

Data Source

PatentUS20240112938A1Method and apparatus for aligning wafer using laser scanner, semiconductor transfer device

Publication Date: 2024.04.04 SYSTEM ENGINEERING MEGA SOLUTION CO LTD

AI summary

A method and apparatus for aligning a wafer using a laser scanner, and a semiconductor transfer device are provided. The method includes a laser irradiation operation of irradiating a laser toward the wafer using a laser scanner disposed on a rear side or a lower side of the wafer and obtaining an image, a dataset acquisition operation of obtaining location information of at least three wafer edges by using a distance corresponding to a laser irradiation direction to a wafer edge in the image, a calculation operation of calculating a center point of the wafer by using the obtained location information of the wafer edge, and a detection operation of detecting whether a calculated center point is within a preset tolerance range.