Dual-Probe Static Charge Measurement for Wafer Surface Accuracy
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Solution Overview
Problem
Existing non-contact apparatuses for measuring static electricity, such as electrostatic fieldmeters and Kelvin probe force microscopes, are inadequate for accurately measuring electrostatic distribution on substrates like wafers due to interference from external electric fields and contamination risks, and are not suitable for substrates with diameters of about 300 mm.
Innovation Solution
A dual-probe apparatus with first and second probes spaced apart by distances smaller than the substrate thickness, each with an earthed casing and separate electrostatic measurement structures, measures static electricity on opposing surfaces of the substrate without contact, using metal or electrostatic dissipative materials to isolate measurement regions and prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrostatic fieldmeter is used to measure static electricity on a substrate surface, then non-contact measurement is achieved, but measurement precision deteriorates due to interference from external electric fields and inability to simultaneously measure both sides of the substrate
Solution Approach 1:
The measurement system is divided into two independent probes, each capable of measuring one side of the substrate simultaneously. Each probe has its own casing and electrostatic measurement structure, allowing independent measurement of electrostatic fields on opposite surfaces without interference from the other side.
Solution Approach 2:
The substrate itself serves as an intermediary that blocks external electric field interference. By positioning probes on opposite sides of the substrate, the substrate thickness acts as a barrier that prevents external fields from reaching both measurement points simultaneously, thereby improving measurement precision.
2Measurement precision
If a Kelvin probe force microscope is used to measure static electricity, then measurement precision improves with ultra-close distance measurement, but object-affected harmful factors worsen due to surface contamination and limited durability
Solution Approach 1:
The measurement approach transitions from one-sided ultra-close measurement to two-sided measurement with appropriate spacing. The probes are positioned at distances smaller than the substrate thickness from each respective surface, enabling measurement without requiring the probes to be in direct contact with the substrate, thus avoiding contamination.
3Adaptability or versatility
If existing measurement apparatuses are used on substrates with diameter of about 300 mm, then measurement capability is provided, but device complexity increases due to spatial resolution limitations and requirement for additional ground plates
Solution Approach 1:
The dual-probe apparatus is designed to measure electrostatic distribution on substrates of various sizes including 300 mm diameter. Both probes can simultaneously measure opposite sides of the substrate, providing comprehensive coverage without requiring additional ground plates or complex configurations, thereby reducing overall device complexity.
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
Accurately measures electrostatic distribution on substrate surfaces without contamination or interference, enabling effective prevention of static electricity-related issues in substrate processing.
Implementation Method 1
a first electrostatic measurement structure provided in the first casing and configured to measure a static electricity in a first measurement region included in the first surface
Implementation Method 2
a second electrostatic measurement structure provided in the second casing and configured to measure a static electricity in a second measurement region included in the second surface
Implementation Method 3
the first casing is earthed to a ground, and the first electrostatic measurement structure is earthed to the ground separately from the first casing
Data Source
AI summary
An apparatus for measuring static electricity according to some embodiments is provided. The apparatus for measuring static electricity includes a first probe spaced apart from a first surface of a measurement object by a first distance; and a second probe spaced apart from a second surface, opposing the first surface in a thickness direction of the measurement object, by a second distance, wherein the first probe includes a first casing, and a first electrostatic measurement structure provided in the first casing and configured to measure static electricity in a first measurement region included in the first surface, wherein the first distance and the second distance are smaller than a thickness of the measurement object.