TWI375288B - Integrated metrology chamber for transparent substrates - Google Patents

Integrated metrology chamber for transparent substrates Download PDF

Info

Publication number
TWI375288B
TWI375288B TW095100110A TW95100110A TWI375288B TW I375288 B TWI375288 B TW I375288B TW 095100110 A TW095100110 A TW 095100110A TW 95100110 A TW95100110 A TW 95100110A TW I375288 B TWI375288 B TW I375288B
Authority
TW
Taiwan
Prior art keywords
substrate
etching
etch
measuring
depth
Prior art date
Application number
TW095100110A
Other languages
English (en)
Chinese (zh)
Other versions
TW200633107A (en
Inventor
Richard Lewington
Corey Collard
Scott Anderson
Khiem Nguyen
Original Assignee
Applied Materials Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Applied Materials Inc filed Critical Applied Materials Inc
Publication of TW200633107A publication Critical patent/TW200633107A/zh
Application granted granted Critical
Publication of TWI375288B publication Critical patent/TWI375288B/zh

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B43WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43KIMPLEMENTS FOR WRITING OR DRAWING
    • B43K29/00Combinations of writing implements with other articles
    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03FPHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/26Phase shift masks [PSM]; PSM blanks; Preparation thereof
    • G03F1/30Alternating PSM, e.g. Levenson-Shibuya PSM; Preparation thereof
    • AHUMAN NECESSITIES
    • A63SPORTS; GAMES; AMUSEMENTS
    • A63HTOYS, e.g. TOPS, DOLLS, HOOPS OR BUILDING BLOCKS
    • A63H29/00Drive mechanisms for toys in general
    • A63H29/24Details or accessories for drive mechanisms, e.g. means for winding-up or starting toy engines
    • AHUMAN NECESSITIES
    • A63SPORTS; GAMES; AMUSEMENTS
    • A63HTOYS, e.g. TOPS, DOLLS, HOOPS OR BUILDING BLOCKS
    • A63H3/00Dolls
    • A63H3/18Jumping jacks
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/677Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for conveying, e.g. between different workstations
    • H01L21/67739Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for conveying, e.g. between different workstations into and out of processing chamber
    • H01L21/67742Mechanical parts of transfer devices
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3105After-treatment
    • H01L21/311Etching the insulating layers by chemical or physical means
    • H01L21/31105Etching inorganic layers
    • H01L21/31111Etching inorganic layers by chemical means
    • H01L21/31116Etching inorganic layers by chemical means by dry-etching

Landscapes

  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Manufacturing & Machinery (AREA)
  • Robotics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Preparing Plates And Mask In Photomechanical Process (AREA)
  • Drying Of Semiconductors (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
  • Testing Or Measuring Of Semiconductors Or The Like (AREA)
TW095100110A 2005-01-08 2006-01-02 Integrated metrology chamber for transparent substrates TWI375288B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US11/031,400 US20060154388A1 (en) 2005-01-08 2005-01-08 Integrated metrology chamber for transparent substrates

Publications (2)

Publication Number Publication Date
TW200633107A TW200633107A (en) 2006-09-16
TWI375288B true TWI375288B (en) 2012-10-21

Family

ID=36098810

Family Applications (1)

Application Number Title Priority Date Filing Date
TW095100110A TWI375288B (en) 2005-01-08 2006-01-02 Integrated metrology chamber for transparent substrates

Country Status (5)

Country Link
US (2) US20060154388A1 (enExample)
EP (1) EP1679548A1 (enExample)
JP (1) JP5392972B2 (enExample)
KR (1) KR101252068B1 (enExample)
TW (1) TWI375288B (enExample)

Families Citing this family (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050197721A1 (en) * 2004-02-20 2005-09-08 Yung-Cheng Chen Control of exposure energy on a substrate
US7601272B2 (en) * 2005-01-08 2009-10-13 Applied Materials, Inc. Method and apparatus for integrating metrology with etch processing
US20060154388A1 (en) * 2005-01-08 2006-07-13 Richard Lewington Integrated metrology chamber for transparent substrates
CN100459087C (zh) * 2006-07-21 2009-02-04 中芯国际集成电路制造(上海)有限公司 确定半导体特征的方法和用于制造集成电路的方法
US8012857B2 (en) * 2007-08-07 2011-09-06 Semiconductor Components Industries, Llc Semiconductor die singulation method
US8859396B2 (en) 2007-08-07 2014-10-14 Semiconductor Components Industries, Llc Semiconductor die singulation method
KR20100061731A (ko) * 2007-09-14 2010-06-08 퀄컴 엠이엠스 테크놀로지스, 인크. Mems 제조에 이용되는 에칭 방법
US7765077B2 (en) * 2007-09-21 2010-07-27 Tokyo Electron Limited Method and apparatus for creating a Spacer-Optimization (S-O) library
CN101889325B (zh) * 2007-12-06 2014-05-07 因特瓦克公司 用于衬底的两侧溅射蚀刻的系统和方法
US7935464B2 (en) * 2008-10-30 2011-05-03 Applied Materials, Inc. System and method for self-aligned dual patterning
US7904273B2 (en) * 2009-02-16 2011-03-08 International Business Machines Corporation In-line depth measurement for thru silicon via
US8232115B2 (en) 2009-09-25 2012-07-31 International Business Machines Corporation Test structure for determination of TSV depth
US8956809B2 (en) * 2012-08-03 2015-02-17 Applied Materials, Inc. Apparatus and methods for etching quartz substrate in photomask manufacturing applications
US9136173B2 (en) 2012-11-07 2015-09-15 Semiconductor Components Industries, Llc Singulation method for semiconductor die having a layer of material along one major surface
US9484260B2 (en) 2012-11-07 2016-11-01 Semiconductor Components Industries, Llc Heated carrier substrate semiconductor die singulation method
US20150132959A1 (en) * 2013-11-08 2015-05-14 Leonard TEDESCHI Pattern formation and transfer directly on silicon based films
US10840102B2 (en) * 2013-11-27 2020-11-17 Taiwan Semiconductor Manufacturing Co., Ltd. Integrated system, integrated system operation method and film treatment method
US9418894B2 (en) 2014-03-21 2016-08-16 Semiconductor Components Industries, Llc Electronic die singulation method
US9385041B2 (en) 2014-08-26 2016-07-05 Semiconductor Components Industries, Llc Method for insulating singulated electronic die
US10095102B2 (en) * 2016-04-12 2018-10-09 Taiwan Semiconductor Manufacturing Co., Ltd. Photomask having a plurality of shielding layers
US10366923B2 (en) 2016-06-02 2019-07-30 Semiconductor Components Industries, Llc Method of separating electronic devices having a back layer and apparatus
US10373869B2 (en) 2017-05-24 2019-08-06 Semiconductor Components Industries, Llc Method of separating a back layer on a substrate using exposure to reduced temperature and related apparatus
US12112959B2 (en) 2018-09-04 2024-10-08 Tokyo Electron Limited Processing systems and platforms for roughness reduction of materials using illuminated etch solutions
KR102740093B1 (ko) * 2018-12-14 2024-12-06 도쿄엘렉트론가부시키가이샤 조명된 에칭 용액을 사용하여 재료의 거칠기를 감소시키기 위한 공정 시스템 및 플랫폼
US10818551B2 (en) 2019-01-09 2020-10-27 Semiconductor Components Industries, Llc Plasma die singulation systems and related methods
JP7365878B2 (ja) * 2019-12-06 2023-10-20 東京エレクトロン株式会社 計測装置及び計測方法

Family Cites Families (80)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5795056A (en) * 1980-12-05 1982-06-12 Hitachi Ltd Appearance inspecting process
JPS61290312A (ja) 1985-06-19 1986-12-20 Hitachi Ltd 断面形状測定装置
US5109430A (en) * 1986-07-22 1992-04-28 Schlumberger Technologies, Inc. Mask alignment and measurement of critical dimensions in integrated circuits
US4767496A (en) * 1986-12-11 1988-08-30 Siemens Aktiengesellschaft Method for controlling and supervising etching processes
US4911103A (en) * 1987-07-17 1990-03-27 Texas Instruments Incorporated Processing apparatus and method
JPH0492444A (ja) * 1990-08-08 1992-03-25 Hitachi Ltd 処理方法および装置
US5171393A (en) * 1991-07-29 1992-12-15 Moffat William A Wafer processing apparatus
US5499733A (en) * 1992-09-17 1996-03-19 Luxtron Corporation Optical techniques of measuring endpoint during the processing of material layers in an optically hostile environment
US5653894A (en) * 1992-12-14 1997-08-05 Lucent Technologies Inc. Active neural network determination of endpoint in a plasma etch process
US5891352A (en) * 1993-09-16 1999-04-06 Luxtron Corporation Optical techniques of measuring endpoint during the processing of material layers in an optically hostile environment
US5452521A (en) * 1994-03-09 1995-09-26 Niewmierzycki; Leszek Workpiece alignment structure and method
US5607800A (en) 1995-02-15 1997-03-04 Lucent Technologies Inc. Method and arrangement for characterizing micro-size patterns
US5711849A (en) * 1995-05-03 1998-01-27 Daniel L. Flamm Process optimization in gas phase dry etching
US6001699A (en) * 1996-01-23 1999-12-14 Intel Corporation Highly selective etch process for submicron contacts
US5798529A (en) * 1996-05-28 1998-08-25 International Business Machines Corporation Focused ion beam metrology
US6060022A (en) * 1996-07-05 2000-05-09 Beckman Coulter, Inc. Automated sample processing system including automatic centrifuge device
US5944940A (en) * 1996-07-09 1999-08-31 Gamma Precision Technology, Inc. Wafer transfer system and method of using the same
US6143081A (en) * 1996-07-12 2000-11-07 Tokyo Electron Limited Film forming apparatus and method, and film modifying apparatus and method
US5948203A (en) * 1996-07-29 1999-09-07 Taiwan Semiconductor Manufacturing Company, Ltd. Optical dielectric thickness monitor for chemical-mechanical polishing process monitoring
US5913102A (en) * 1997-03-20 1999-06-15 Taiwan Semiconductor Manufacturing Company, Ltd. Method for forming patterned photoresist layers with enhanced critical dimension uniformity
US5926690A (en) * 1997-05-28 1999-07-20 Advanced Micro Devices, Inc. Run-to-run control process for controlling critical dimensions
US5976740A (en) * 1997-08-28 1999-11-02 International Business Machines Corporation Process for controlling exposure dose or focus parameters using tone reversing pattern
US5965309A (en) * 1997-08-28 1999-10-12 International Business Machines Corporation Focus or exposure dose parameter control system using tone reversing patterns
US6161054A (en) * 1997-09-22 2000-12-12 On-Line Technologies, Inc. Cell control method and apparatus
US6129807A (en) * 1997-10-06 2000-10-10 Applied Materials, Inc. Apparatus for monitoring processing of a substrate
US6124212A (en) * 1997-10-08 2000-09-26 Taiwan Semiconductor Manufacturing Co. High density plasma (HDP) etch method for suppressing micro-loading effects when etching polysilicon layers
US5963329A (en) * 1997-10-31 1999-10-05 International Business Machines Corporation Method and apparatus for measuring the profile of small repeating lines
US6148239A (en) * 1997-12-12 2000-11-14 Advanced Micro Devices, Inc. Process control system using feed forward control threads based on material groups
US6054710A (en) * 1997-12-18 2000-04-25 Cypress Semiconductor Corp. Method and apparatus for obtaining two- or three-dimensional information from scanning electron microscopy
US6452677B1 (en) * 1998-02-13 2002-09-17 Micron Technology Inc. Method and apparatus for detecting defects in the manufacture of an electronic device
US6033814A (en) * 1998-02-26 2000-03-07 Micron Technology, Inc. Method for multiple process parameter matching
US6067357A (en) * 1998-03-04 2000-05-23 Genesys Telecommunications Laboratories Inc. Telephony call-center scripting by Petri Net principles and techniques
IL125338A0 (en) * 1998-07-14 1999-03-12 Nova Measuring Instr Ltd Method and apparatus for monitoring and control of photolithography exposure and processing tools
JP4601744B2 (ja) * 1998-07-14 2010-12-22 ノバ メジャリング インスツルメンツ リミテッド フォトリソグラフィープロセスを制御するための方法およびシステム
US6424733B2 (en) * 1998-07-20 2002-07-23 Micron Technology, Inc. Method and apparatus for inspecting wafers
US6183594B1 (en) * 1998-09-25 2001-02-06 International Business Machines Corporation Method and system for detecting the end-point in etching processes
JP3090139B1 (ja) * 1999-03-05 2000-09-18 ミノルタ株式会社 プロジェクタ用光学系
WO2000058188A1 (en) * 1999-03-25 2000-10-05 N & K Technology, Inc. Wafer handling robot having x-y stage for wafer handling and positioning
US6455437B1 (en) * 1999-04-07 2002-09-24 Applied Materials Inc. Method and apparatus for monitoring the process state of a semiconductor device fabrication process
EP1065567A3 (en) * 1999-06-29 2001-05-16 Applied Materials, Inc. Integrated critical dimension control
US6166509A (en) * 1999-07-07 2000-12-26 Applied Materials, Inc. Detection system for substrate clamp
US6368975B1 (en) * 1999-07-07 2002-04-09 Applied Materials, Inc. Method and apparatus for monitoring a process by employing principal component analysis
US6583065B1 (en) 1999-08-03 2003-06-24 Applied Materials Inc. Sidewall polymer forming gas additives for etching processes
EP1079426A1 (en) 1999-08-16 2001-02-28 Applied Materials, Inc. Integration scheme using selfplanarized dielectric layer for shallow trench isolation (STI)
US6225639B1 (en) 1999-08-27 2001-05-01 Agere Systems Guardian Corp. Method of monitoring a patterned transfer process using line width metrology
US6707544B1 (en) 1999-09-07 2004-03-16 Applied Materials, Inc. Particle detection and embedded vision system to enhance substrate yield and throughput
US6721045B1 (en) * 1999-09-07 2004-04-13 Applied Materials, Inc. Method and apparatus to provide embedded substrate process monitoring through consolidation of multiple process inspection techniques
US6413867B1 (en) * 1999-12-23 2002-07-02 Applied Materials, Inc. Film thickness control using spectral interferometry
JP3974319B2 (ja) * 2000-03-30 2007-09-12 株式会社東芝 エッチング方法
EP1269521A1 (en) * 2000-04-07 2003-01-02 Varian Semiconductor Equipment Associates Inc. WAFER ORIENTATION SENSOR FOR GaAs WAFERS
US6245581B1 (en) * 2000-04-19 2001-06-12 Advanced Micro Devices, Inc. Method and apparatus for control of critical dimension using feedback etch control
US6411389B1 (en) * 2000-05-03 2002-06-25 The Regents Of The University Of Claifornia Optical monitor for real time thickness change measurements via lateral-translation induced phase-stepping interferometry
WO2001084382A1 (en) 2000-05-04 2001-11-08 Kla-Tencor, Inc. Methods and systems for lithography process control
US6625512B1 (en) 2000-07-25 2003-09-23 Advanced Micro Devices, Inc. Method and apparatus for performing final critical dimension control
IL139368A (en) 2000-10-30 2006-12-10 Nova Measuring Instr Ltd Process control for microlithography
US6625497B2 (en) * 2000-11-20 2003-09-23 Applied Materials Inc. Semiconductor processing module with integrated feedback/feed forward metrology
US20020147960A1 (en) * 2001-01-26 2002-10-10 Applied Materials, Inc. Method and apparatus for determining scheduling for wafer processing in cluster tools with integrated metrology and defect control
US6653231B2 (en) * 2001-03-28 2003-11-25 Advanced Micro Devices, Inc. Process for reducing the critical dimensions of integrated circuit device features
US6525829B1 (en) * 2001-05-25 2003-02-25 Novellus Systems, Inc. Method and apparatus for in-situ measurement of thickness of copper oxide film using optical reflectivity
US6479309B1 (en) * 2001-05-25 2002-11-12 Advanced Micro Devices, Inc. Method and apparatus for determining process layer conformality
US20030000922A1 (en) * 2001-06-27 2003-01-02 Ramkumar Subramanian Using scatterometry to develop real time etch image
US6649426B2 (en) 2001-06-28 2003-11-18 Advanced Micro Devices, Inc. System and method for active control of spacer deposition
US20030045098A1 (en) * 2001-08-31 2003-03-06 Applied Materials, Inc. Method and apparatus for processing a wafer
US20030052084A1 (en) * 2001-09-18 2003-03-20 Tabery Cyrus E. In-situ or ex-situ profile monitoring of phase openings on alternating phase shifting masks by scatterometry
US20030092281A1 (en) * 2001-11-13 2003-05-15 Chartered Semiconductors Manufactured Limited Method for organic barc and photoresist trimming process
US6960416B2 (en) * 2002-03-01 2005-11-01 Applied Materials, Inc. Method and apparatus for controlling etch processes during fabrication of semiconductor devices
JP4197103B2 (ja) 2002-04-15 2008-12-17 株式会社荏原製作所 ポリッシング装置
US6762130B2 (en) * 2002-05-31 2004-07-13 Texas Instruments Incorporated Method of photolithographically forming extremely narrow transistor gate elements
US6825487B2 (en) * 2002-07-30 2004-11-30 Seh America, Inc. Method for isolation of wafer support-related crystal defects
JP4584531B2 (ja) * 2002-08-02 2010-11-24 株式会社日立製作所 異物モニタリングシステム
US6939811B2 (en) * 2002-09-25 2005-09-06 Lam Research Corporation Apparatus and method for controlling etch depth
US20040200574A1 (en) * 2003-04-11 2004-10-14 Applied Materials, Inc. Method for controlling a process for fabricating integrated devices
US8257546B2 (en) * 2003-04-11 2012-09-04 Applied Materials, Inc. Method and system for monitoring an etch process
US7094613B2 (en) * 2003-10-21 2006-08-22 Applied Materials, Inc. Method for controlling accuracy and repeatability of an etch process
US7250309B2 (en) * 2004-01-09 2007-07-31 Applied Materials, Inc. Integrated phase angle and optical critical dimension measurement metrology for feed forward and feedback process control
KR100568867B1 (ko) * 2004-03-18 2006-04-10 삼성전자주식회사 웨이퍼 좌표감지장치 및 그 웨이퍼 좌표감지 기능을 갖는반도체 제조설비
US7076320B1 (en) * 2004-05-04 2006-07-11 Advanced Micro Devices, Inc. Scatterometry monitor in cluster process tool environment for advanced process control (APC)
US6961626B1 (en) * 2004-05-28 2005-11-01 Applied Materials, Inc Dynamic offset and feedback threshold
US20060154388A1 (en) * 2005-01-08 2006-07-13 Richard Lewington Integrated metrology chamber for transparent substrates
US7601272B2 (en) * 2005-01-08 2009-10-13 Applied Materials, Inc. Method and apparatus for integrating metrology with etch processing

Also Published As

Publication number Publication date
US20060154388A1 (en) 2006-07-13
TW200633107A (en) 2006-09-16
JP5392972B2 (ja) 2014-01-22
JP2006194878A (ja) 2006-07-27
US20070012660A1 (en) 2007-01-18
US7846848B2 (en) 2010-12-07
EP1679548A1 (en) 2006-07-12
KR101252068B1 (ko) 2013-04-15
KR20060081365A (ko) 2006-07-12

Similar Documents

Publication Publication Date Title
TWI375288B (en) Integrated metrology chamber for transparent substrates
US7250309B2 (en) Integrated phase angle and optical critical dimension measurement metrology for feed forward and feedback process control
TWI387039B (zh) 整合測量法與蝕刻製程的方法及設備
US6819426B2 (en) Overlay alignment metrology using diffraction gratings
CN107430352B (zh) 量测方法、量测设备和器件制造方法
US9709905B2 (en) System and method for dark field inspection
US7065737B2 (en) Multi-layer overlay measurement and correction technique for IC manufacturing
US20070072435A1 (en) Method for plasma etching a chromium layer through a carbon hard mask suitable for photomask fabrication
JP2019507375A (ja) パターン形成プロセスを制御する方法、リソグラフィ装置、メトロロジ装置リソグラフィックセル、および関連するコンピュータプログラム
US20080248403A1 (en) Method and system for improving critical dimension uniformity
US7733502B2 (en) Roughness evaluation method and system
CN101055422B (zh) 用于透明基材的整合式测量室
KR102363560B1 (ko) 탄소 오염 방지를 위한 euv 마스크
US7759136B2 (en) Critical dimension (CD) control by spectrum metrology
HK1114426A (en) Integrated metrology chamber for transparent substrates
TW201719277A (zh) 修復光罩的方法
Dieu et al. Advanced 193 tri-tone EAPSM (9% to 18%) for 65-nm node

Legal Events

Date Code Title Description
MM4A Annulment or lapse of patent due to non-payment of fees