Wafer Processing Sensor with Exposable Sensing Layers
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Solution Overview
Problem
Existing techniques for measuring material deposition and removal in semiconductor wafer processing tools lack real-time measurement and control, relying on indirect estimates and requiring frequent sensor replacement, which disrupts the fabrication process.
Innovation Solution
Incorporating micro sensors with selectively exposable sensing layers and mask layers, allowing for continuous monitoring and refreshing without interrupting the process, by using etchants to expose fresh sensing layers as the old ones degrade.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are used to measure material deposition and removal rates, then measurement precision is improved, but the sensors degrade over time and require replacement, causing process interruptions
Solution Approach 1:
The sensor is divided into multiple sensing layers stacked vertically, with each layer having its own mask layer. When one sensing layer degrades, the system can switch to another layer, extending the overall sensor lifespan without requiring complete sensor replacement and causing process interruptions.
Solution Approach 2:
Multiple sensing layers are prepared in advance with mask layers protecting them. The system proactively switches to a fresh sensing layer before the current one completely degrades, ensuring continuous measurement capability and avoiding process interruptions.
2Measurement precision
If sensors are replaced frequently to maintain measurement accuracy, then measurement precision is improved, but productivity decreases due to process interruptions
Solution Approach 1:
By segmenting the sensor into multiple sensing layers, the system eliminates the need for frequent complete sensor replacements. Each layer can be independently used and then switched to the next layer, maintaining measurement precision while avoiding process interruptions and preserving productivity.
Solution Approach 2:
The multi-layer sensor design ensures continuous measurement capability by allowing seamless switching between layers. This eliminates gaps in measurement and prevents process interruptions, maintaining both measurement precision and productivity throughout the wafer fabrication process.
3Duration of action of moving object
If multiple sensors are used to extend monitoring capability, then duration of action is improved, but device complexity increases
Solution Approach 1:
Multiple sensing layers are merged into a single integrated sensor structure, sharing common support infrastructure, mask layer application processes, and switching mechanisms. This combining approach extends the monitoring duration while minimizing the increase in device complexity compared to using completely separate sensor units.
Solution Approach 2:
The sensing layers are arranged in a nested vertical stack, with each layer contained within the same spatial footprint. This nesting arrangement extends the monitoring duration without proportionally increasing the device's external dimensions or structural complexity, as all layers share the same support structure and interface connections.
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
Enables real-time, accurate monitoring of material deposition and removal rates, extending the lifespan of the sensors and reducing process interruptions by allowing for continuous operation of the wafer processing equipment.
Implementation Method 1
The mask layer may be removed to expose the sensing layer when the other micro sensor reaches an end-of-life
Data Source
AI summary
Embodiments include devices and methods for detecting particles, monitoring etch or deposition rates, or controlling an operation of a wafer fabrication process. In an embodiment, one or more micro sensors are mounted on wafer processing equipment, and are capable of measuring material deposition and removal rates in real-time. The micro sensors are selectively exposed such that a sensing layer of a micro sensor is protected by a mask layer during active operation of another micro sensor, and the protective mask layer may be removed to expose the sensing layer when the other micro sensor reaches an end-of-life. Other embodiments are also described and claimed.