Oxidized Wafer Voltage Scanning for Burl Top Particle Detection
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Solution Overview
Problem
Existing methods struggle to accurately measure the free form flatness of substrate tables and detect sub-micron particles on burl tops during the manufacturing and installation of wafer tables and clamps, leading to reduced yield and increased contamination in semiconductor manufacturing processes.
Innovation Solution
The use of a thermally-oxidized substrate with a thermally-grown insulating layer, electrostatically clamped to a substrate table, allows for the application of variable voltages to detect burl top contamination and measure free form flatness under atmospheric conditions, using a metrology system to ensure proper electrical connections and vacuum clamping for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional measurement methods are used for substrate table flatness, then the measurement process is simple, but the measurement precision is insufficient for sub-micron particle detection
Solution Approach 1:
A test substrate with an insulating layer is introduced as an intermediary between the substrate table and the measurement system. The substrate acts as a mediator that enables electrostatic clamping and facilitates precise flatness measurements through voltage application, allowing detection of sub-micron particles without direct contact between the measurement apparatus and the substrate table.
Solution Approach 2:
The patent replaces traditional mechanical measurement systems with an electrostatic-based measurement system. By applying voltages to the test substrate and measuring the resulting electrostatic forces and flatness changes, the system achieves sub-micron measurement precision without complex mechanical contact mechanisms.
2Measurement precision
If electrostatic clamping is applied to detect particles, then the detection precision improves, but the device complexity increases due to additional electrical connections and voltage control
Solution Approach 1:
The test substrate with insulating layer serves multiple functions simultaneously: it provides electrostatic clamping to the substrate table, acts as a measurement platform for flatness detection, and enables particle detection through voltage application. This multi-functionality reduces the need for separate dedicated components for each function.
Solution Approach 2:
The system utilizes changes in electrical parameters (voltage magnitude and polarity) to detect particles. By varying the applied voltage and monitoring the resulting electrostatic force changes or flatness variations, the system achieves sensitive particle detection without requiring complex physical sensors at each measurement point.
3Measurement precision
If variable voltage is applied to an oxidized wafer, then sub-micron particles can be detected, but the manufacturing precision requirements increase for the oxidized layer thickness
Solution Approach 1:
The patent utilizes the electrical properties (dielectric constant, breakdown voltage) of the thermally-grown insulating layer as the key parameter for particle detection, rather than relying solely on precise thickness control. By applying variable voltages and monitoring electrostatic responses, the system can detect particles across a range of oxidation thicknesses, reducing the stringency of manufacturing precision requirements.
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 method enables efficient detection of sub-micron particles and precise measurement of free form flatness, improving yield and reducing contamination by allowing for real-time cleaning and accurate qualification of wafer tables and clamps, thus enhancing semiconductor manufacturing efficiency.
Implementation Method 1
a substrate electrical connection configured to transmit a voltage to the semiconducting layer to electrostatically clamp the second substrate surface to the substrate table
Implementation Method 2
a first thermally-grown insulating layer disposed on a first face of the semiconducting layer
Data Source
AI summary
Systems, apparatuses, methods, and computer program products are provided for determining a free form flatness of a substrate table. An example system can include a substrate table that includes a first substrate table surface and a grounded substrate table electrical connection configured to ground the substrate table. The system can further include a substrate that includes a semiconducting layer, a thermally-grown insulating layer, a first substrate surface disposed on the insulating layer, and a substrate electrical connection configured to transmit a voltage to the semiconducting layer. The system can further include a metrology system configured to apply a voltage to the substrate electrical connection to electrostatically clamp the substrate to the substrate table, measure a flatness of the first substrate surface, and determine a free form flatness of the first substrate table surface based on the measured flatness of the first substrate surface.