Substrate Mounting Structure with Thermal Breaking Unit
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Solution Overview
Problem
Existing substrate processing apparatuses face challenges in maintaining temperature uniformity and preventing explosive gas explosions due to the thick stem acting as a heat flow path and potential software control failures.
Innovation Solution
A substrate mounting structure with a thin-walled cylinder pillar portion and a thermal breaking unit inside the mounting stage, which mechanically breaks the electrical power supply line, reducing heat capacity and preventing heat transfer to the base portion, and optionally filled with a heat insulating material to enhance temperature control and prevent explosions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stem is made thicker to cover the thermostat, then the reliability of heating-stop control is improved, but the heat capacity of the stem increases and heat is not properly transferred to the wafer
Solution Approach 1:
The stem is segmented into two distinct parts: an upper thick-walled portion that provides structural support and houses the thermostat, and a lower thin-walled portion that minimizes heat absorption and allows efficient heat transfer to the wafer. This segmentation resolves the contradiction by localizing the thick structure only where needed for reliability while maintaining thermal efficiency in the heat transfer path.
Solution Approach 2:
Different parts of the stem have different wall thicknesses optimized for their specific functions: the upper part has thick walls for structural integrity and thermostat housing, while the lower part has thin walls for minimal heat interference. This local quality differentiation allows the system to achieve both reliable heating-stop control and proper heat transfer to the wafer.
2Strength
If the stem is made thicker to house the thermostat, then the mechanical strength and support are improved, but the stem absorbs more heat and functions as a heat flow path to the processing chamber wall
Solution Approach 1:
The stem is divided into segments with different wall thicknesses: the upper segment has thick walls for structural strength and thermostat accommodation, while the lower segment has thin walls to minimize heat absorption and reduce energy loss to the processing chamber wall, thus resolving the contradiction between strength and energy efficiency.
Solution Approach 2:
The stem exhibits local quality variation in wall thickness, with the thicker upper portion providing mechanical strength and the thinner lower portion minimizing thermal mass and heat loss, allowing the system to simultaneously achieve structural integrity and energy efficiency.
3Adaptability or versatility
If software control is used for heating-stop control, then the control flexibility is improved, but the reliability is reduced due to potential software runout
Solution Approach 1:
A thermostat is introduced as an intermediary mechanical device that directly senses the susceptor temperature and mechanically breaks the feed line to stop heating when the explosion limit temperature is reached. This intermediary provides a reliable backup control mechanism that operates independently of software, ensuring heating-stop control reliability while software maintains its flexibility for normal operation.
Solution Approach 2:
The thermostat is pre-configured to mechanically interrupt the heating circuit when temperature reaches the explosion limit, providing a safety cushion against software failure. This prior cushioning ensures that even if software control fails, the system will automatically stop heating to prevent explosive gas ignition.
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
Improves the reliability of heating-stop control, maintains uniform substrate temperature, and prevents explosive gas explosions by ensuring heat is efficiently transferred to the substrate while minimizing heat loss to the base portion.
Implementation Method 1
a thermal breaking unit that mechanically breaks an electrical power supply line connected to the heating element depending on a temperature of the substrate
Implementation Method 2
the pillar portion comprises a thin-walled cylinder, and the thermal breaking unit is disposed on the pillar portion's internal space side in the mounting stage
Implementation Method 3
Making the stem thicker increases the heat capacity of the stem, and hence the stem absorbs a considerable amount of heat generated by the heating element of the susceptor
Implementation Method 4
the mounting stage comprises a heating element that heats the mounted substrate
Data Source
AI summary
A substrate mounting structure that can maintain the temperature uniformity of a substrate mounted on a mounting stage. The substrate mounting structure disposed in a pressure reduced space has a base portion, a pillar portion mounted in a standing manner on the base portion and having an internal space, and a mounting stage supported on the pillar portion and having a substrate mounted thereon. The mounting stage has a heating element that heats the mounted substrate, and a thermal breaking unit that mechanically breaks an electrical power supply line connected to the heating element depending on the temperature of the substrate. The pillar portion is comprised of a thin-walled cylinder. The thermal breaking unit is disposed on the pillar portion's internal space side in the mounting stage, and the pressure in the internal space is reduced.