Dual-Camera Wafer Positioning for Thermal Alignment Correction

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Solution Overview

Problem

The existing processing apparatuses face challenges in maintaining accurate positional alignment between the reference positions of upper and lower image capturing units due to thermal deviations, which can lead to oblique cuts in wafers during processing.

Innovation Solution

A positioning method that involves detecting and storing reference positions for both image capturing units, calculating deviations, and correcting the coordinate systems to ensure alignment on a horizontal XY plane, thereby reducing positional deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the processing apparatus operates for extended periods, then productivity is improved, but thermal deviations cause positional accuracy to deteriorate

Engineering Contradiction:

Improveprocessing throughputVSAvoidreference position alignment

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system performs preliminary positioning of the chuck table and image capturing units before processing begins. Reference positions are detected and stored in advance, and coordinate systems are pre-calibrated to establish accurate spatial relationships between multiple image capturing units before thermal effects accumulate during operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors positional deviations between reference positions of image capturing units and performs real-time corrections. The coordinate system correction unit adjusts for thermal deviations by comparing detected positions against stored reference data and applying compensatory transformations to maintain alignment accuracy during extended operation.

Inventive Principle:

Principle #23Feedback

2Stability of the object's composition

If the chuck table and image capturing units are fixed rigidly, then positional stability is improved, but thermal expansion causes positional deviation to worsen

Engineering Contradiction:

Improverelative positional relationVSAvoidreference position coincidence

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The system changes the coordinate system parameters through mathematical transformations to compensate for thermal deviations. By detecting actual positions and calculating appropriate coordinate transformations, the system adjusts reference positions dynamically to account for thermal expansion and contraction, maintaining precision despite temperature variations.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system explicitly accounts for thermal expansion effects by detecting positional deviations caused by heat and applying corrective coordinate transformations. The correction unit compensates for dimensional changes in the chuck table and image capturing units due to thermal effects, ensuring reference positions remain coincident despite thermal expansion.

Inventive Principle:

Principle #37Thermal expansion

3Measurement precision

If multiple image capturing units are used to detect oblique cuts, then detection accuracy is improved, but maintaining their reference position alignment becomes more complex

Engineering Contradiction:

Improveoblique cut detection accuracyVSAvoidreference position management

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The coordinate system correction unit serves multiple image capturing units simultaneously, applying universal correction algorithms to align reference positions across all units. This multi-functional approach manages the complexity of coordinating multiple sensors by using a unified correction framework that handles positional deviations for all image capturing units in a systematic manner.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12272102B2Positioning method

Publication Date: 2025.04.08 DISCO CORP

AI summary

A positioning method includes detecting coordinates (X11, Y11) of a rotation center on a surface of a holding table with a first image capturing unit and stores the detected coordinates as a new first reference position, detecting coordinates (X21, Y21) of a rotation center on another surface of the holding table with a second image capturing unit and stores the detected coordinates as a new second reference position, calculating a first deviation between a previous rotation center on the surface of the holding table and the coordinates (X11, Y11), calculating a second deviation between a previous rotation center on the other surface of the holding table and the coordinates (X21, Y21), correcting a coordinate system of images captured by the first image capturing unit to eliminate the first deviation, and correcting a coordinate system of images captured by the second image capturing unit to eliminate the second deviation.