Silicone Foam Gas Line Heater With Thermal Transition Layer
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Solution Overview
Problem
Existing gas line heater systems in semiconductor fabrication face issues with temperature limitations, premature failure due to brittleness at high temperatures, and non-uniform heat distribution, particularly with silicone foam rubber insulation and wire wound heater elements.
Innovation Solution
A high-to-low heat transition layer is introduced between a heater element and a silicone foam rubber insulation layer, using a thermally insulating material to reduce temperature by at least 90°C, with a foil etch heater element and mechanical thermal fuses for precise temperature control and enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If silicone foam rubber insulation is used to insulate heater elements, then flexibility and cleanliness are improved, but temperature resistance deteriorates (cannot withstand beyond 162°C)
Solution Approach 1:
The insulation system is divided into multiple layers: an inner high-temperature resistant layer (alumina-silica foam or ceramic fiber) that contacts the heater element and withstands temperatures up to 250°C or higher, and an outer silicone foam rubber layer that provides flexibility and cleanliness benefits. This segmentation allows each layer to perform its specialized function without compromise.
Solution Approach 2:
The patent employs a composite insulation structure combining dissimilar materials with complementary properties. The inner layer uses inorganic high-temperature materials (alumina-silica foam, ceramic fiber) while the outer layer uses organic silicone foam rubber. This composite approach achieves both high temperature resistance and flexibility simultaneously.
2Power
If wire wound heater elements are used, then heating capability is provided, but temperature control precision deteriorates (temperature overshoots target temperature)
Solution Approach 1:
The patent transitions from wire wound heater elements to foil etch heater elements, changing the physical and electrical parameters of the heating element. Foil etch elements provide lower resistance and more uniform heat distribution, enabling precise temperature control within ±10°C of target temperature rather than overshooting.
3Power
If wire wound heater elements are used, then heating is provided, but heat distribution uniformity deteriorates (heat flux is less uniform between separate regions)
Solution Approach 1:
The patent changes the physical configuration of the heating element from wire wound to foil etch construction. The foil etch design with its serpentine pattern and direct contact surface provides uniform heat flux distribution across all regions of the heater, eliminating the non-uniformity inherent in wire wound elements.
4Ease of manufacture
If mechanical thermal fuses are used instead of electronic temperature limit control devices, then cost is reduced, but temperature resistance requirement deteriorates (mechanical fuses have lower temperature limits)
Solution Approach 1:
The temperature control system is segmented into two independent components: a primary control system using foil etch heater elements with feedback control for precise temperature regulation, and a secondary safety system using mechanical thermal fuses as backup protection. This segmentation allows the use of inexpensive mechanical fuses without exposing them to the full operating temperature.
Solution Approach 2:
The inner high-temperature insulation layer acts as an intermediary that protects the mechanical thermal fuses from direct exposure to high temperatures. By positioning the fuses in the outer insulation layer away from the heater element, the intermediate insulation barrier maintains the fuses within their operational temperature range while still providing safety function.
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 solution allows for reliable operation at temperatures up to 250°C, prevents premature failure, and ensures uniform heat distribution, enabling efficient and controlled heating of gas lines in semiconductor fabrication.
Implementation Method 1
a thermal transition layer (70) having an inner surface and an outer surface spaced apart by a thickness... said thermal transition layer and said thickness being selected to reduce the temperature from said inner surface to said outer surface by at least 90° C.
Implementation Method 2
a heater element containing layer (55) adhesively bonded to said first surface
Data Source
AI summary
A semi-flexible laminar silicone foam rubber-base heater for high temperature gas supply and exhaust lines used in microelectronic semiconductor fabrication uses superimposed adhesively bonded layers of an etched foil heater element containing layer, a high-to-low heat thermal transition layer, a thermal fuse laden silicone foam rubber insulation layer and a durable wrapping layer. The system can provide for the combined use of highly controllable etched foil heater elements, clean silicone foam rubber insulation, and inexpensive mechanical thermal fuses safely in a high heat gas supply and exhaust line environment.