Water-Cooled Backplate for PVD Wafer Temperature Control
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Solution Overview
Problem
High-powered transistor manufacturing using thick aluminium layers faces challenges in maintaining wafer temperature within safe limits during physical vapour deposition, as high deposition rates generate excessive heat, and existing temperature control methods are costly and inefficient.
Innovation Solution
An aluminium support surface coated with a heat-absorbing coating, such as CrOx or Al2O3, is cooled to around 100° C to maintain the workpiece temperature between 350° C and 450° C, effectively managing heat without requiring costly gas or mechanical clamping systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high deposition rates are used to meet productivity demands, then productivity is improved, but wafer temperature increases excessively
Solution Approach 1:
A water-cooled molybdenum backplate is introduced as an intermediary heat management component between the wafer and the cooling system. The backplate conducts heat away from the wafer substrate during high-power sputtering, enabling high deposition rates while maintaining wafer temperature within acceptable limits
Solution Approach 2:
A water cooling system is implemented to actively remove heat from the backplate during the sputtering process. The hydraulic cooling flow enables continuous operation at high powers by maintaining thermal management, thus supporting high deposition rates without excessive temperature buildup
2Temperature
If conventional cooling methods (gas conduction or mechanical clamping) are used, then wafer temperature is controlled, but device complexity and cost increase
Solution Approach 1:
The invention replaces complex mechanical clamping cooling systems with a simpler integrated water-cooled backplate design. The backplate serves dual functions as both the mechanical support substrate holder and the thermal management component, eliminating the need for separate mechanical clamping mechanisms and reducing overall system complexity
Solution Approach 2:
The backplate is designed to perform multiple functions simultaneously: it serves as the mechanical support structure for the wafer, the thermal conduction path for heat removal, and the interface for water cooling. This multi-functionality reduces the number of separate components needed and simplifies the overall cooling system design
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 effectively regulates wafer temperature, preventing overheating and maintaining it within the safe range, while allowing for high deposition rates without the need for expensive cooling methods, and results in smaller grain sizes and improved process control.
Implementation Method 1
providing an aluminium surface coated with a heat absorbing coating
Implementation Method 2
cooling the support to around 100° C
Implementation Method 3
deposited onto a semiconductor device embedded on a full thickness wafer
Implementation Method 4
Aluminium and aluminium films may be deposited onto wafers by magnetron sputtering techniques
Data Source
AI summary
Methods and related apparatus support a work piece during a physical vapor deposition. An aluminium support having a support surface coated with a heat absorbent coating is provided. The support is cooled to around 100° C. and a PVD process is performed such that, with cooling, the work piece temperature is between 350° C. and 450° C. The coating is inert and/or ultra-high voltage compatible.