Fixed Laser Substrate Warpage Measurement
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Solution Overview
Problem
Existing vapor phase growth apparatuses face challenges in accurately measuring substrate warpage and inclination due to the movement of position measuring apparatuses, leading to difficulties in achieving high measurement accuracy.
Innovation Solution
A rotation/revolution type vapor phase growth apparatus equipped with a laser source and light receiving portion fixed on a laser transparent portion of the chamber, which continuously irradiates a rotating substrate with laser light and receives reflected light to judge substrate states, with the optical axis aligned on the substrate's center locus, and the substrate retaining member's revolutions set as a non-integral multiple of the susceptor's, allowing for precise and stable measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a position measuring apparatus is moved to measure substrate warpage, then the substrate state can be measured, but measurement accuracy deteriorates due to small displacements of the measuring apparatus
Solution Approach 1:
The measurement function is segmented from the substrate handling system. The laser source and light receiving portion are separated into independent components that remain fixed on the chamber, while only the substrate rotates on the susceptor. This segmentation eliminates the coupling between measurement apparatus movement and substrate rotation, resolving the measurement accuracy issue.
Solution Approach 2:
A laser beam is introduced as an intermediary between the fixed measuring apparatus and the rotating substrate. The laser light serves as a non-contact mediator that can penetrate through the rotating motion, allowing measurement without physical contact or movement of the measuring devices themselves.
2Productivity
If the substrate retaining member rotates with integral multiple of susceptor revolutions, then the measurement can be completed in fewer cycles, but measurement accuracy deteriorates due to repeated measurement of the same substrate positions
Solution Approach 1:
The rotational relationship between the substrate retaining member and susceptor is made asymmetric by setting the number of revolutions to a non-integral multiple. This asymmetric rotation ensures that the substrate presents different positions and orientations to the fixed laser measurement point during each rotation cycle, enabling comprehensive warpage measurement across the entire substrate surface.
Solution Approach 2:
The measurement system transitions from measuring only at fixed radial positions to measuring across multiple dimensional positions by utilizing the non-integral multiple rotation. This causes the laser to scan across different radial and angular positions of the substrate, effectively adding dimensional coverage to the measurement process.
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 setup enables precise and stable measurement of substrate warpage and inclination, preventing abnormal states and ensuring high-quality thin film deposition by avoiding vapor phase growth on warped or inclined substrates, thus improving the yield and reproducibility of thin films.
Implementation Method 1
a light receiving portion which receives a laser light reflected on the surface of the substrate
Implementation Method 2
a heating means which heats a substrate retained in the substrate retaining concave portion
Implementation Method 3
a vapor phase growth apparatus in which, while rotating/revolving a substrate, a thin film is epitaxially grown on the surface of the substrate by a chemical reaction using, in particular, a pyrolytic reaction of an organic metal
Data Source
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AI summary
Provided is a vapor phase growth apparatus provided with a measuring means which can measure the state of the warpage or inclination of a substrate with high accuracy, which is a rotation/revolution type vapor phase growth apparatus provided with a susceptor and a plurality of substrate retaining members in a chamber, wherein a measuring means comprising a laser source which continuously emits a laser light in a direction perpendicular to the surface of the substrate which is retained in the substrate retaining member and is rotating/revolving by the rotation of the susceptor and a light receiving portion which receives a laser light reflected on the surface of the substrate is fixed on the outer surface of a laser transparent portion provided on the chamber; and a judging means which judges that the substrate is in an abnormal state when the variation of the reflected light received by the light receiving portion is larger than a preset variation is provided.