Non-Contact Probe Endpoint Detection for Semiconductor Wafers
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Solution Overview
Problem
Current endpoint detection methods for semiconductor wafer processing are inadequate, especially as technology nodes shrink, leading to inefficiencies in determining process completion, which can result in wasted resources and defective circuits.
Innovation Solution
A semiconductor processing apparatus with a non-contact probe, optical transmitter, and optical receiver that generates surface potential and height profiles to control the processing station based on delta changes, allowing for in-situ, non-contact endpoint detection independent of the tools used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reflective measurement device is used for endpoint detection, then the optical signal can be measured, but the measurement becomes inaccurate when film thickness is very thin
Solution Approach 1:
The patent replaces the mechanical/optical reflective measurement system with an electrical field-based non-contact probe system. The probe measures surface voltage and current characteristics without physical contact or optical reflection, enabling accurate endpoint detection for ultra-thin films where optical methods fail.
Solution Approach 2:
The invention changes the measurement parameter from optical reflectance to electrical surface voltage and current characteristics. This parameter transformation allows detection of endpoint conditions in thin film stacks that are invisible to optical methods, as the electrical field penetrates and interacts with the thin dielectric layers differently than light.
2Productivity
If continued processing is performed after a failed process step, then production continues, but defective circuits are produced and resources are wasted
Solution Approach 1:
The system implements real-time feedback through continuous monitoring of surface voltage and current characteristics during processing. When endpoint conditions are detected or abnormal patterns are identified, the system provides immediate feedback to stop processing, preventing defective circuit formation while maintaining productivity through accurate process control.
3Measurement precision
If a non-contact probe with optical signal transmission is used, then in-situ endpoint detection is enabled, but the device complexity increases
Solution Approach 1:
The non-contact probe system is designed with multi-functionality, serving both as an endpoint detection device and a process monitoring tool. The same probe structure that transmits optical signals also measures surface voltage and current characteristics, reducing overall system complexity by consolidating multiple measurement functions into a single integrated device.
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 approach enables efficient and accurate endpoint detection by identifying process step completion through delta changes in surface potential and height profiles, reducing waste and ensuring proper circuit formation.
Implementation Method 1
an optical transmitter configured to transmit an optical signal to the non-contact probe, and an optical receiver configured to receive a reflected optical signal from the non-contact probe
Data Source
AI summary
A semiconductor processing apparatus includes a semiconductor processing station for a semiconductor wafer, and an endpoint detector associated with the semiconductor processing station. The endpoint detector includes a non-contact probe configured to probe the semiconductor wafer, an optical transmitter configured to transmit an optical signal to the non-contact probe, and an optical receiver configured to receive a reflected optical signal from the non-contact probe. The controller controls the semiconductor processing station based on the reflected optical signal.