Shutter Blade CTE Compensation Design
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Solution Overview
Problem
In semiconductor processing, temperature variations cause misalignment and damage to shutter disks and robot blades in substrate processing chambers, leading to improper deposition and reduced process performance due to uncoordinated thermal expansion and contraction.
Innovation Solution
A processing chamber element positioning system with a thermal compensating member having a higher coefficient of thermal expansion (CTE) than the positioning member, designed to maintain alignment and prevent deposition on critical components by using a distance ratio that matches the CTE ratio, ensuring consistent positioning despite temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shutter blade is used in a PVD chamber, then the shutter disk can be positioned to protect the substrate support during burn-in and pasting processes, but the shutter disk position shifts due to thermal expansion and contraction of the blade, causing misalignment and potential damage to the heater
Solution Approach 1:
The patent applies thermal expansion compensation by incorporating a bimetallic strip or differential expansion mechanism in the shutter blade assembly. The blade is constructed with materials having different coefficients of thermal expansion that are mechanically coupled to counteract each other's expansion, maintaining the shutter disk's radial position relative to the heater despite temperature changes during PVD processes
Solution Approach 2:
The patent changes the physical parameters of the shutter blade by selecting specific materials with controlled thermal properties and designing the blade geometry to compensate for thermal effects. The blade structure incorporates elements with different thermal expansion characteristics to maintain dimensional stability of the shutter disk position across temperature variations
2Manufacturing precision
If the shutter disk position is not precisely maintained, then misalignment occurs exposing the heater to unplanned deposition and damage, but adding complex positioning correction mechanisms increases device complexity
Solution Approach 1:
The shutter blade assembly is designed to self-compensate for thermal expansion effects through its inherent bimetallic or differential expansion structure. The system automatically maintains positioning accuracy without requiring external sensors, actuators, or control systems to detect and correct drift, thereby achieving high precision without increased device complexity
3Measurement precision
If robot blade substrate positioning is not compensated for temperature changes, then the robot blade center reference point location varies, causing misalignment during substrate transfer, but implementing compensation increases system complexity
Solution Approach 1:
The robot blade assembly incorporates thermal expansion compensation through bimetallic strips or differential expansion mechanisms that actively counteract the thermal drift of the substrate reference point. As temperature changes occur during substrate transfer between hot and cold zones, the compensation mechanism maintains the robot blade center reference point at its programmed location without requiring complex sensor-based correction systems
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 system effectively maintains the alignment of shutter disks and robot blades, preventing damage and ensuring consistent deposition performance across varying temperatures, thereby extending the usable life of chamber components and improving process reliability.
Implementation Method 1
a thermal compensating member having a second CTE greater than the first CTE... A distance ratio of the first distance to the third distance is substantially equal to a CTE ratio of the second CTE to the first CTE
Data Source
AI summary
Processing chamber shutter blade and robot blade assemblies are constructed to eliminate thermal effects on the placement of elements in processing chambers. Such blade assemblies may contain at least two parts, which may include a positioning member including a low CTE material and a thermal compensating member including a high CTE material. The positioning member includes a coupling point and a reference point on a reference axis separated by a first distance. The thermal compensating member includes a connection point and a controlled point separated by another distance that is less than the first distance. A distance ratio of the first distance to the other distance is substantially equal to a CTE ratio of the high CTE material to the low CTE material, and the positioning member is joined to the thermal compensating member through the coupling point and the connection point.