Sputter Target Backing Plate Erosion Grooves
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Solution Overview
Problem
Current sputter deposition methods lack a reliable and cost-effective way to detect the end-of-life (EOL) of sputter targets, leading to potential contamination of processed elements due to erosion beyond the target material, especially when the target erodes down to a different material backing plate, causing undesired deposition of backing plate material.
Innovation Solution
A backing plate with strategically positioned holes or grooves that expose the target receiving part through the backing plate material, allowing the sputter process to abort immediately when erosion grooves reach these points, maintaining vacuum integrity and preventing contamination by connecting to the exterior of the process chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sputter target is allowed to erode completely, then the target life is extended and productivity is improved, but the backing plate material contaminates the deposited layer and reliability deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-forming erosion grooves or channels in the backing plate before the sputter target is fully consumed. These grooves are strategically positioned to guide the erosion process, ensuring that when the target material is depleted, the erosion naturally follows the pre-designed path and exposes the backing plate in a controlled manner, preventing uncontrolled contamination of the deposited layer.
Solution Approach 2:
The backing plate is segmented into different functional zones with distinct properties. The erosion grooves create separate regions: a target mounting area, erosion channels with specific geometry, and a backing plate exposure zone. This segmentation allows each region to perform its specific function - the target area for deposition, the grooves for guiding erosion, and the exposure zone for controlled end-of-life detection.
2Reliability
If the target is monitored frequently to detect end-of-life, then the deposited layer purity is maintained, but the device complexity and cost increase
Solution Approach 1:
The backing plate performs self-service by incorporating visible indicators (erosion grooves, color-coded regions, or geometric features) that automatically signal the end-of-life status. As the target erodes, these indicators become progressively visible or change appearance, providing real-time feedback without requiring external monitoring equipment. The system essentially monitors itself through the physical state of the backing plate.
Solution Approach 2:
The patent utilizes color changes as a visual indicator of target erosion status. Different regions of the backing plate are assigned distinct colors or reflectivity characteristics, and as the target erodes, these colored regions become visible through the target material or at the edges. This provides an intuitive, no-cost monitoring mechanism where the operator can visually assess target life and purity status without complex instrumentation.
3Measurement precision
If the backing plate structure is modified to expose the target receiving part, then the EOL detection precision is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the backing plate, specifically the depth, width, and orientation of erosion grooves. These geometric parameters are optimized to control the erosion progression and expose the target receiving part at precise moments. By adjusting these parameters during design, the EOL detection precision is enhanced while maintaining compatibility with standard manufacturing processes.
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
Ensures reliable EOL detection and extended target life by preventing contamination, allowing for efficient sputtering until the target erodes down to the backing plate, ensuring high-quality deposited layers without unwanted material from the backing plate.
Implementation Method 1
During sputter deposition material, e.g. atoms, released from a target condensate on a substrate to form a layer
Implementation Method 2
the target formed of the material from which the desired layer is to be formed erodes more and more, e.g., erosion grooves may be formed which advance towards the backing plate
Data Source
AI summary
A backing plate for a sputter target includes a target receiving part for receiving a target to be sputtered, and a structure for exposing the target receiving part through the backing plate.