Substrate Hot Plate Heating with Staged Evacuation Control
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Solution Overview
Problem
Existing heating apparatuses face challenges in suppressing substrate defects caused by substances generated during heating while maintaining uniformity of the coating film on the substrate surface.
Innovation Solution
A heating apparatus with a processing vessel, hot plate, and exhaust devices, controlled by a controller, adjusts the substrate height and evacuation modes to manage the processing space, ensuring gentle temperature variation and timely evacuation of the processing space, to prevent defects by timely evacuation of generated substances without affecting film uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If evacuation is performed continuously during heating, then substrate defects are suppressed, but coating film uniformity deteriorates
Solution Approach 1:
The heating process is divided into multiple phases with different evacuation states. In the first phase (heating from ambient to first temperature), evacuation is not performed to maintain coating film uniformity. In the second phase (heating from first temperature to second temperature), evacuation is performed to suppress substrate defects. This temporal segmentation allows each phase to optimize for its specific requirement without compromising the other.
Solution Approach 2:
The evacuation system dynamically adjusts its operation based on the heating phase. The controller switches the evacuation pump between ON and OFF states according to the temperature range being traversed. This dynamic control enables the system to adapt evacuation performance to the specific needs of each heating stage, resolving the contradiction between defect suppression and film uniformity.
2Productivity
If substrate is placed close to hot plate, then heating efficiency is improved, but temperature uniformity deteriorates
Solution Approach 1:
The heating process is segmented into two distinct temperature ranges with different substrate positioning requirements. In the first phase (ambient to first temperature), the substrate is positioned away from the hot plate to ensure uniform heating. In the second phase (first temperature to second temperature), the substrate is moved closer to the hot plate to enhance heating efficiency for defect suppression. This segmentation allows optimization of both temperature uniformity and heating efficiency at different stages.
3Reliability
If heating temperature is increased, then defect suppression is improved, but coating film quality deteriorates
Solution Approach 1:
The heating process is divided into two temperature phases. The first phase heats the substrate to a first temperature (e.g., 100-200°C) without evacuation, preserving coating film quality. The second phase continues heating to a second temperature (e.g., 200-400°C) while activating evacuation, which suppresses defects. This segmentation allows the system to achieve both high temperature defect suppression and coating film quality preservation.
Solution Approach 2:
The system performs preliminary heating to the first temperature before activating evacuation. This preliminary action ensures that the coating film is already heated to a stable state before the evacuation phase begins, preventing thermal shock and maintaining film uniformity while still achieving defect suppression at the higher second temperature.
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
The apparatus effectively suppresses substrate defects and maintains coating film uniformity by controlling substrate height and evacuation phases, ensuring efficient collection of generated substances during heating.
Implementation Method 1
a hot plate having a placement surface on which the substrate accommodated in the processing space is placed, and a heating device configured to heat the substrate
Implementation Method 2
an exhaust device configured to evacuate the processing space
Data Source
AI summary
A heating apparatus includes a processing vessel forming therein a processing space in which a substrate is accommodated; a hot plate having a placement surface on which the substrate is placed, and a heating device configured to heat the substrate; an adjusting mechanism configured to adjust a height of the substrate with respect to the hot plate; an exhaust device configured to evacuate the processing space; and a controller. The controller performs: starting a heating processing of the substrate by setting the height of the substrate with respect to the hot plate to a predetermined height; and setting, when the heating processing reaches a predetermined progress level, the height of the substrate with respect to the hot plate to be lower than the predetermined height to place the substrate on or close to the hot plate, and switching evacuation of the processing space from OFF to ON.