Smart EFEM Metrology Integration for Faster Wafer Processing
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Solution Overview
Problem
The semiconductor wafer processing time is lengthy due to extensive handling and idle time in Equipment Front End Modules (EFEMs) while waiting for metrology and processing, leading to inefficiencies in microchip production.
Innovation Solution
Integration of a Smart EFEM with a metrology module, pre-alignment module, robotic wafer handler, and sequencing module that allows simultaneous metrology data collection during idle times, reducing the need for separate metrology steps and enhancing wafer tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate metrology steps are performed after processing modules, then measurement precision is improved, but processing time increases and productivity decreases
Solution Approach 1:
The patent combines the metrology module with the EFEM to create an integrated system. The metrology module is physically integrated into the EFEM structure, allowing measurement functions to be merged with wafer handling operations. This eliminates separate metrology steps and enables simultaneous wafer transfer and measurement activities, resolving the contradiction between measurement precision and productivity.
Solution Approach 2:
The system performs metrology measurements on idle wafers while they are waiting in the wafer carrier, before they are actually needed for processing. This preliminary measurement action utilizes otherwise wasted time, so when wafers enter the processing flow, measurement data is already available, eliminating post-processing metrology steps and improving throughput.
2Manufacturing precision
If wafers are handled sequentially through multiple EFEMs, then manufacturing precision is maintained, but processing time increases and idle time increases
Solution Approach 1:
The integrated metrology-EFEM system enables continuous useful action by performing measurements on wafers during idle periods in the wafer carrier. While one wafer is being processed, the system prepares and measures subsequent wafers in advance. This continuous utilization of system resources eliminates idle time and maintains precision through controlled, sequential handling.
Solution Approach 2:
The system performs preliminary measurements and preparations on wafers while they are idle in the carrier, before they are actually needed for processing. This advance preparation ensures that when wafers enter the processing sequence, all necessary measurements are complete, eliminating waiting time and maintaining manufacturing precision.
3Loss of information
If comprehensive metrology data collection is performed, then measurement precision and tracking accuracy are improved, but processing time increases
Solution Approach 1:
The system collects comprehensive metrology data on wafers during idle time in the wafer carrier, before they enter the processing flow. This preliminary data collection includes flatness, surface defects, film thickness, and other measurements. By completing data collection in advance, the system achieves complete tracking information without adding time to the critical processing path.
Solution Approach 2:
The system recovers otherwise wasted idle time in the wafer carrier by performing metrology measurements during this period. The idle time is transformed into productive measurement time, so comprehensive data collection is achieved without extending processing time, as the measurements occur during previously unused periods.
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 significantly reduces processing time by 20% and ensures comprehensive data collection and tracking throughout the fabrication process, optimizing wafer handling and reducing idle time.
Implementation Method 1
an optical modulator (e.g., rotating chopper, rotating diffuser, rotating grating, rotating polarizer, or rotating wave plate) coupled to an axis rotated by a motor
Implementation Method 2
a light source configured to project structured light onto a surface of the semiconductor wafer
Implementation Method 3
an optical sensor configured to capture an image of the semiconductor wafer by light reflected from the surface of the semiconductor wafer
Data Source
AI summary
A method for using a smart EFEM in a semiconductor wafer process facility that incorporates at least one metrology testing device in a metrology unit positioned in operational proximity to the pre-alignment unit. The pre-alignment unit has a metrology chuck (platter) that two robotic arms shuttle the Si wafers onto, and that has a dimeter equivalent or larger than the diameter of the Si wafers being processed/analysed. The metrology unit may be rotated about an axis or the per-aligner chuck may be rotated so long as structured light used in the interferometric and ellipsometric signals is rotated about the wafer. This enables high resolution data to be collected at every process step with no impact to process cycle time. And will allow full wafer tracking throughout the entire fabrication process for every wafer. This data can be uploaded into the operational mainframe computer of the analysis and processing network and subjected to AI pattern analysis to diagnose issues in the process before they can affect production yield.