Ion Energy Determination via Impedance Matching Model
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Solution Overview
Problem
Current methods for monitoring and controlling plasma systems in semiconductor manufacturing, such as using bias compensation devices and voltage probes, are costly, time-consuming, and prone to malfunctions, leading to inaccurate measurements of ion energy and wafer bias.
Innovation Solution
A method and system that utilize an impedance matching model to determine ion energy by measuring complex voltage and current at the output of an RF generator, eliminating the need for voltage probes and bias compensation devices, and calculating wafer bias and ion energy based on peak voltage and RF voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage probes and bias compensation devices are used to measure ion energy and wafer bias, then measurement capability is provided, but system cost and operational time increase
Solution Approach 1:
The patent creates an electrical model that replicates the behavior of the plasma system, allowing ion energy and wafer bias to be calculated from the model outputs rather than measured directly with physical probes. This virtual copy eliminates the need for time-consuming direct measurements while maintaining measurement capability.
Solution Approach 2:
The patent replaces physical measurement devices (voltage probes and bias compensation devices) with an electrical modeling approach. By substituting mechanical/physical measurement systems with computational electrical models, the system achieves measurement capabilities without the time penalties of physical probe insertion and adjustment.
2Measurement precision
If voltage probes and bias compensation devices are used to measure ion energy and wafer bias, then measurement capability is provided, but system cost increases
Solution Approach 1:
The patent creates an electrical model that replicates the behavior of the plasma system, allowing ion energy and wafer bias to be calculated from the model outputs rather than measured directly with physical probes. This virtual copy eliminates the need for expensive direct measurement equipment while maintaining measurement capability.
Solution Approach 2:
The patent replaces physical measurement devices (voltage probes and bias compensation devices) with an electrical modeling approach. By substituting mechanical/physical measurement systems with computational electrical models, the system achieves measurement capabilities without the high costs associated with specialized measurement hardware.
3Reliability
If direct measurement methods are used, then ion energy can be determined, but measurement accuracy is compromised due to device malfunctions
Solution Approach 1:
The patent creates an electrical model that replicates the behavior of the plasma system, allowing ion energy and wafer bias to be calculated from the model outputs rather than measured directly with physical probes. This virtual copy eliminates the need for time-consuming direct measurements while maintaining measurement capability.
Solution Approach 2:
The patent introduces an electrical model as an intermediary between the plasma system and the measurement process. This intermediary layer processes electrical signals and calculates ion energy and wafer bias without requiring direct physical contact with the plasma, thereby eliminating measurement errors caused by probe malfunctions while maintaining measurement capability.
Data Source
AI summary
Systems and methods for determining ion energy are described. One of the methods includes detecting output of a generator to identify a generator output complex voltage and current (V&I). The generator is coupled to an impedance matching circuit and the impedance matching circuit is coupled to an electrostatic chuck (ESC). The method further includes determining from the generator output complex V&I a projected complex V&I at a point along a path between an output of a model of the impedance matching circuit and a model of the ESC. The operation of determining of the projected complex V&I is performed using a model for at least part of the path. The method includes applying the projected complex V&I as an input to a function to map the projected complex V&I to a wafer bias value at the ESC model and determining an ion energy from the wafer bias value.