Load-Lock LED Substrate Heating to Prevent Thermal Recalibration
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Solution Overview
Problem
Thermal expansion of substrates during defect review in automated inspection apparatuses leads to recalibration needs, reducing throughput due to uneven heating before reaching operating temperature.
Innovation Solution
A closed-loop controlled light-emitting diode (LED) array is used to actively warm the substrate in a load-lock chamber to match the stage temperature before initial calibration, minimizing thermal expansion and eliminating recalibration requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate is heated unevenly before reaching operating temperature, then the substrate will experience thermal expansion, but this leads to recalibration needs that reduce throughput
Solution Approach 1:
The substrate is heated to the operating temperature of the stage in the load-lock chamber before being transferred to the vacuum chamber. This preliminary heating action ensures the substrate reaches thermal equilibrium beforehand, preventing thermal expansion during the inspection process and eliminating the need for recalibration, thereby maintaining high throughput
Solution Approach 2:
The patent replaces conventional contact-based heating methods with optical heating (using light sources). This non-contact heating method allows for uniform temperature distribution across the substrate surface without mechanical contact, achieving better temperature uniformity and preventing thermal expansion issues
2Manufacturing precision
If the substrate is heated to match stage temperature before transfer, then thermal expansion is minimized, but this requires additional heating equipment in the load-lock chamber
Solution Approach 1:
The heating system in the load-lock chamber uses the same type of light source and control mechanisms as the inspection system. The optical heating apparatus serves multiple purposes: it can heat the substrate to operating temperature, and the same light source can be used for inspection processes, reducing overall system complexity
Solution Approach 2:
The substrate heating process utilizes the substrate's own properties (absorption of optical energy) to generate heat internally. The substrate absorbs light energy and converts it to thermal energy directly where needed, eliminating the need for complex external heating mechanisms and thermal conduction paths
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 reduces thermal expansion, maintaining consistent field of view and enhancing throughput by ensuring the substrate reaches equilibrium temperature before defect review, thus preventing unnecessary recalibrations.
Implementation Method 1
A closed-loop controlled light-emitting diode (LED) array is used to actively warm the substrate in a load-lock chamber
Implementation Method 2
The substrate is then warmed using a light-emitting diode array while the substrate is in the load-lock chamber
Implementation Method 3
Thermal expansion of substrates during defect review in automated inspection apparatuses leads to recalibration needs
Data Source
AI summary
One embodiment relates to an apparatus for vacuum-compatible substrate thermal management. The apparatus includes a load-lock chamber coupled to a vacuum chamber, a light-emitting diode array, and a substrate stage. The load-lock chamber is configured to hold a substrate prior to the substrate being transferred into the vacuum chamber, and a substrate stage is configured to hold the substrate in the vacuum chamber. The light-emitting diode array is configured to warm the substrate while the substrate is in the load-lock chamber. Other features, aspects and embodiments are also disclosed.