SAW Sensor Packaging for Semiconductor Chamber Environments
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Solution Overview
Problem
Surface acoustic wave (SAW) sensors are unable to withstand the harsh processing environments of semiconductor processing chambers, including corrosive plasmas and RF energy, and their materials are not permitted in semiconductor processing equipment.
Innovation Solution
A sensing device with packaging layers and a waveguide that includes a transmitter and receiver, using ceramic materials and protective coatings to prevent interference and contamination, with a thickness less than the electromagnetic wavelength of SAW sensor radio waves, allowing specific frequencies to pass through while blocking others.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If SAW sensors are deployed in semiconductor processing chambers, then sensing capability is improved, but the sensors cannot withstand harsh processing environments including corrosive plasmas and RF energy
Solution Approach 1:
A packaging structure made of ceramic materials serves as an intermediary barrier between the SAW sensor and the harsh plasma environment. The packaging includes a first packaging layer and second packaging layer that together provide protection while allowing the sensor to function. This intermediary structure resolves the contradiction by shielding the sensor from corrosive plasmas and RF energy while maintaining sensing capability.
Solution Approach 2:
The packaging structure uses composite ceramic materials that combine protective properties with electromagnetic filtering capabilities. The composite structure includes multiple layers with different properties - some layers provide mechanical protection and chemical resistance, while others provide RF filtering. This composite approach enables the sensor to withstand harsh environments while maintaining measurement precision.
2Reliability
If packaging layers are added to protect SAW sensors, then reliability in harsh environments is improved, but device complexity increases
Solution Approach 1:
The packaging structure performs multiple functions simultaneously: it provides mechanical protection, chemical resistance to plasma, RF energy filtering, and electromagnetic shielding. By consolidating these multiple protective functions into a single integrated packaging assembly, the design avoids the complexity of adding separate components for each function. The packaging layers are designed to be multi-functional, resolving the contradiction between protection and complexity.
3Object-affected harmful factors
If packaging layers with protective coatings are used, then resistance to corrosive plasmas is improved, but interference with RF energy and process gases may occur
Solution Approach 1:
The packaging materials and their thicknesses are carefully selected and optimized to change the electromagnetic parameters (frequency response, attenuation) to allow process gases to pass through while blocking harmful RF energies. The ceramic materials are chosen for their specific dielectric properties that enable plasma resistance while maintaining RF transparency at operating frequencies. This parameter optimization resolves the contradiction between plasma resistance and RF interference.
Solution Approach 2:
Different regions of the packaging structure have different properties optimized for specific functions. For example, certain areas may have thicker protective coatings for plasma resistance, while other areas have optimized thickness for RF transparency. The packaging layers are designed with spatially varying properties to simultaneously achieve plasma protection and minimize RF interference, resolving the local quality contradiction.
4Ease of operation
If traditional SAW sensor materials are used, then sensing function is achieved, but materials are not permitted in semiconductor processing equipment
Solution Approach 1:
The ceramic packaging structure serves as an intermediary barrier that isolates traditional SAW sensor materials from the semiconductor processing environment. This intermediary packaging allows the sensor to maintain its sensing function using conventional materials while preventing those materials from contaminating the processing chamber. The packaging layers are designed to be impermeable to process gases and plasma, resolving the contradiction between sensor functionality and material compatibility.
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
The sensing device effectively monitors process parameters in semiconductor processing chambers without interfering with or contaminating the environment, providing added sensing capability for controlling semiconductor processes while withstanding harsh conditions.
Implementation Method 1
The first waveguide includes a first filter to allow the sensing frequency to pass therethrough
Implementation Method 2
Surface acoustic wave (SAW) sensors are unable to withstand the harsh processing environments
Implementation Method 3
The packaging may have a thickness chosen such that the thickness is less than the electromagnetic wavelength of a SAW sensor radio wave
Data Source
AI summary
The implementations described herein generally relate to a sensing device for use in the semiconducting industry, which sense process parameters to control semiconductor processes. More specifically, the implementations relate to packaging for a surface acoustic wave (SAW) based devices or wireless or RF-responsive sensors for use in the harsh processing environments of a semiconductor processing chamber such that the neither the sensor and its components nor the chamber components interfere with or contaminate one another. The sensor packaging may include various packaging layers with or without protective coatings and a waveguide. The packaging may have a thickness chosen such that the thickness is less than the electromagnetic wavelength of a SAW sensor radio wave. The sensing devices may be disposed in cavities of the chamber, the processing volume, on chamber components, and/or on the substrate.