AECAPC Product Technology Overview

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AEC/APC Product Technology Overview

• IMA Presentation October 2006
• AEC/APC Symposium XVIII
• Verity Instruments, Inc.
• By
• Mike Whelan

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AEC/APC Product Technology Overview

• Current Technology
• OES with PCA PLS
• IEP for etch
• Reflectometry for CVD, CMP
• Emerging technology
• Real Time Smart Detector
• XTFR very thin film monitor

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Current Technology
Spectrographs For OES EP, FDC and Plasma
Diagnostics UV-Vis NIR
Spectral Reflectometer For In Situ IEP in Etch
Deposition and In-line Film Thickness
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Current Technology
SD1024D Optical Emission Spectroscopy with PCA
PLS
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OES with PCA PLS

• OES Optical Emission Spectroscopy
• OES Endpoint Detection (EPD)
• PCA, reference model in same wafer
• PCA, reference model in separate wafer
• OES Fault Detection and Classification (FDC)
• Using OES PLS for Gate CD control
• O2 Flow rates are PSI (Process State Indicator)

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OES Endpoint Detection using PCA

• PCA is a multivariate analysis technique that
• Allows easy work with data samples that have a
  large number of variables
• Effective for data compression and information
  extraction
• Requires little prior knowledge of the system
• It is used in OES EP detection because
• Enables you to detect patterns, differences and
  changes of data samples,
• There are a large number of data analysis
  techniques that are based on PCA, and
• With the appropriate software it is easy to use

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PCA Endpoint

• Method 1 -
• Model of process state is created in early part
  of data taking (before EP)
• Later part of data is compared to model to find
  endpoint
• Method 2
• Data from one benchmark run is calibration state
• Trend is calculated in real time on subsequent
  runs
• Requires at least one reference data file that is
  a good representation of the normal, desired
  state of the tool. This is used to create the
  PCA model.
• Q and T2 statistic can be the PSI (Process State
  Indicator)
• Both are available to select in Veritys
  software

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PCA Endpoint Example Method 1
Endpoint
Model Region

• Typical Results

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PCA Endpoint Software
SpectraView fast, flexible and highly
programmable for special or propriety applications
real-time
calibration
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OES FDC using PLS

• PLS is a multivariate analysis technique that
• Finds the covariance between a few important
  process variables and data samples that have a
  large number of variables, and
• Can predict selected process variables from a
  large set of data variables.
• It is used in OES FDC because
• Has great sensitivity and specificity, and
• Can be expanded to many simultaneous process
  variables.

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OES FDC Process Example using PLS

• Motivation
• Gate CD is a critical parameter for DRAM etch
  
• O2 Flow Rate has been shown to correlate to
  CD skew ( Kim et al, ISSM 2005)
• Goal
• Detect with high resolution the O2 flow
  variation in the etch process by OES
• In so doing, control Gate CD

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PLS OES FDC

• Calibrated on data from range of flow rates.
• Requires at least two reference data files at
  different flow rates for calibration
• Then measure flow rate in real time on
  subsequent runs
• PSI is a direct measure of the flow rate
• Verity holds a patent for this method of FDC
  (US Patent 6830939)
• See Kenneth Harveys AEC/APC presentation
  Method for Real Time Monitoring of Gas
  Composition With High Sensitivity Using
  Optical Emission Spectroscopy

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PLS - FDC

• SpectraView fast , flexible and highly
  programmable for propriety applications

real-time
calibration
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PLS - FDC

• Result of PLS calibration with new data

PSI (0.2 sccm/div)
O2 flow (0.2 sccm/div)
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Current Technology

• SP2003
• IEP - Reflectometry

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Interferometric Endpoint (IEP)

• In-situ Real Time Wafer Reflection Measurements
• Layer thickness, etch depth
• Enables etch control when no stop layer exists
• Useful for gate etch, trench and recess etches
• Verity works with OEM toolmakers to engineer
  customized integration (software and hardware)

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Motivation for In-Situ IEP

• Provides much (not all) of the value of
  standalone metrology with the benefit of the
  following -
• 100 wafer sampling
• No latency
• No throughput reduction
• No additional wafer-handling requirements
• Also supports fault detection
• Process excursions are identified immediately

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Interferometric Endpoint

• Advantages of Veritys approach
• Pulsed Xe Light Source
• Full spectrum (200 800 nm)
• High brightness
• Long life (109 flashes up to 5 years)
• Plasma light and illumination light are
  separated

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Interferometric Endpoint (IEP)
Typical Etch Installation
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Interferometric Endpoint

• Screen Shots showing spectra (updated at 10 Hz)

Raw Signals Flash On (red) Si Wafer Reflection
Reference (black)
Computed Signal Wafer Reflectance
Raw Signal Flash Off Plasma Emission
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Interferometric Endpoint

• Other SP2003 APC Applications
• In line Reflectometry for CVD
• Film thickness measurement
• Measure chamber to chamber variations
• FDC
• In Situ APC for CMP
• Metal breakthrough
• Transition detection
• Multiple input capability of the SD1024D permits
  multi-zone monitoring

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CMP in-situ Example
Three probes simultaneously monitor three wafer
zones. Algorithms detect metal breakthrough
separately in each zone
Center-fast polish
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Emerging Technology
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Emerging Technology

• SD1024X
• Fully Embedded Smart Spectrograph

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Rationale for Development AEC / APC

• Existing Products
• Industrial PC for Endpoint
• Windows OS Non-Deterministic, Vulnerable to
  Viruses
• Multiple Connection points - Degraded
  Communication / Latency
• Hardware Additional failure points /
  Reliability risk
• Marketplace
• Industry Demands .. Verity SD1024X Solution
• Efficiency / Reliability / Flexibility - H/W, S/W
  Modularity
• Standardization Interface A / e-Diagnostics
• Automation Smart Sensor w R/T Feedback
• State of the art Support Remote
  Configuration/Troubleshooting

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SD1024X OverView

• SD1024X
• Spectral Acquisition
• Collects and forwards to X-NeT

• X-NeT Embedded Application
• Capable of all OES and IEP Processing
  functions.
• Industry Standard Real-Time Operating System.
• Eliminates need for dedicated external computer
• Direct Tool connections and communications
• Remote (Ethernet based) User Interface

Trigger DI/O
Optics
RS232 -or- TCP/IP Data Tool Control
Internal Storage (Could be Solid State)
Ethernet
TCP/IP HTML / XML JAVA
Remote SpectraNeT User Interface
Ethernet
Ethernet
LAN Auto Archive
Remote Data Storage
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1024X OFF-LINE User Interface

• SD1024X (X-NeT SW)
• Performing OES/IEP functions under Tool Control

Optics

• SpectraNeT
• (On Remote Users Windows PC)
• Used Off-Line for - Data Review / Reprocessing
  - Recipe Editing - Log file Analysis- All
  remaining Functions

Transfer Files and DISCONNECT from X
SpectraNeT FunctionPlug-ins
Remote Data Storage
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Modularity of Software

• Verity Example

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X-NeT / SpectraNeT BENEFITS

• Deterministic Timing
• Via Real-Time Operating System.
• Reliable OS (Verity Control of OS Functions)
• OS Kernel w/minimum feature set needed.
• Security
• SEMI standards (E132) for User and Equipment
  Authentication will be followed
• Common User Interface
• SpectraNeT UI can be used with or without an
  SD1024X connection
• Remote Access
• Spectra NET UI - direct Ethernet, across a LAN or
  Internet.
• Internet access would allow Factory
  troubleshooting.
• Reduced Down-Time
• Removable Media allows Hardware of a faulty
  SD1024X in lt 10minutes
• Modular Software Approach
• Allows user customization

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Emerging Technology

• XTFR
• Xtreme Thin Film Reflectometer

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XTFR the Need

• Nitridated SiO2 is a popular high k- gate
  dielectric for next generation devices
• The nitridation process causes change in the
  physical thickness of the oxide film
• This has led to growing interest in monitoring
  pre-Nitridated and post-Nitridated films
  thicknesses
• We have demonstrated a patent pending
  reflectometer technique that is capable of
  measuring sub 10A films with high precision
• This technique is based on heterodyne
  interferometry

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XTFR Layout

• Employs single wavelength at fixed incidence
  angle
• Nominal thickness range, 0 - 1000Å
• Extendable by switching ?
• Resolution 0.08Å
• Unlike ellipsometry XTFR can measure thickness
  directly

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Physics of XTFR

• At Brewsters angle, a, s- polarization (?) is
  reflected from film surface as well as film
  substrate interface while p- polarized light is
  reflected only by the latter.
• Mixing s- (?) and p- (? ? ?) polarizations
  generates a beat signal at frequency ? ?.
  This signal is embedded with phase information
  that corresponds to film thickness.

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XTFR measurements SiO2 and SiON Films
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XTFR Precision Measurement
Short term (7-min) Precision 0.76 12-hr
Precision 1.0 DT 30C (over 12-hr period)
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Potential Advantages

• Uses single non-actinic wavelength at fixed
  incidence angle
• Mitigates photo contamination issues
• Current measurement resolution of 0.08Å
• Static repeatability of 0.76
• Application Gate dielectrics, possibly thin
  metal films
• Can be integrated with process tool

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Summary

• Verity Instruments provides
• Variety of Opto-instrument APC solutions
• Process state control (OES)
• Wafer state control (IEP, Reflectometry)
• OEM tool integration focus
• Compact, robust industrial designs
• Products that support FDC
• Emerging technology to support next generation
• 25 years of Semi Industry commitment
• Verity Instruments is a founding member of the
  Integrated Measurement Association