KR100284663B1 - 웨이퍼 감지 및 클램핑 모니터 - Google Patents

웨이퍼 감지 및 클램핑 모니터 Download PDF

Info

Publication number
KR100284663B1
KR100284663B1 KR1019940000410A KR19940000410A KR100284663B1 KR 100284663 B1 KR100284663 B1 KR 100284663B1 KR 1019940000410 A KR1019940000410 A KR 1019940000410A KR 19940000410 A KR19940000410 A KR 19940000410A KR 100284663 B1 KR100284663 B1 KR 100284663B1
Authority
KR
South Korea
Prior art keywords
wafer
support
electrodes
capacitance
circuit
Prior art date
Legal status (The legal status 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 status listed.)
Expired - Lifetime
Application number
KR1019940000410A
Other languages
English (en)
Korean (ko)
Other versions
KR940018947A (ko
Inventor
가스킬 블레이크 쥴리안
투 웨일린
케이트 스톤 데일
칼레톤 홀덴 스콧트
Original Assignee
브라이언 알. 바흐맨
액셀리스 테크놀로지스 인크.
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
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=21713775&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=KR100284663(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by 브라이언 알. 바흐맨, 액셀리스 테크놀로지스 인크. filed Critical 브라이언 알. 바흐맨
Publication of KR940018947A publication Critical patent/KR940018947A/ko
Application granted granted Critical
Publication of KR100284663B1 publication Critical patent/KR100284663B1/ko
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus 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
    • H01L21/68—Apparatus 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 positioning, orientation or alignment
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus 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
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67242—Apparatus for monitoring, sorting or marking
    • H01L21/67259—Position monitoring, e.g. misposition detection or presence detection
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus 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
    • H01L21/683—Apparatus 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 supporting or gripping
    • H01L21/6831—Apparatus 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 supporting or gripping using electrostatic chucks

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Container, Conveyance, Adherence, Positioning, Of Wafer (AREA)
  • Measurement Of Resistance Or Impedance (AREA)
  • Jigs For Machine Tools (AREA)
  • Machine Tool Sensing Apparatuses (AREA)
KR1019940000410A 1993-01-15 1994-01-12 웨이퍼 감지 및 클램핑 모니터 Expired - Lifetime KR100284663B1 (ko)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US08/005,030 US5436790A (en) 1993-01-15 1993-01-15 Wafer sensing and clamping monitor
US005,030 1993-01-15

Publications (2)

Publication Number Publication Date
KR940018947A KR940018947A (ko) 1994-08-19
KR100284663B1 true KR100284663B1 (ko) 2001-04-02

Family

ID=21713775

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1019940000410A Expired - Lifetime KR100284663B1 (ko) 1993-01-15 1994-01-12 웨이퍼 감지 및 클램핑 모니터

Country Status (7)

Country Link
US (1) US5436790A (enExample)
EP (1) EP0607043B1 (enExample)
JP (1) JP3341221B2 (enExample)
KR (1) KR100284663B1 (enExample)
CA (1) CA2113290C (enExample)
DE (1) DE69400113T2 (enExample)
TW (1) TW231366B (enExample)

Families Citing this family (76)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5467249A (en) * 1993-12-20 1995-11-14 International Business Machines Corporation Electrostatic chuck with reference electrode
US5463525A (en) * 1993-12-20 1995-10-31 International Business Machines Corporation Guard ring electrostatic chuck
GB2293689A (en) * 1994-09-30 1996-04-03 Nec Corp Electrostatic chuck
EP0871843B1 (en) * 1994-10-17 2003-05-14 Varian Semiconductor Equipment Associates Inc. Mounting member and method for clamping a flat thin conductive workpiece
US5671116A (en) * 1995-03-10 1997-09-23 Lam Research Corporation Multilayered electrostatic chuck and method of manufacture thereof
US5670066A (en) * 1995-03-17 1997-09-23 Lam Research Corporation Vacuum plasma processing wherein workpiece position is detected prior to chuck being activated
US5754391A (en) * 1996-05-17 1998-05-19 Saphikon Inc. Electrostatic chuck
US6298737B1 (en) * 1996-05-29 2001-10-09 Integrated Device Technology, Inc. Ceramic ring undersize detection device
US5812362A (en) * 1996-06-14 1998-09-22 Applied Materials, Inc. Method and apparatus for the use of diamond films as dielectric coatings on electrostatic chucks
US5952060A (en) * 1996-06-14 1999-09-14 Applied Materials, Inc. Use of carbon-based films in extending the lifetime of substrate processing system components
US5980194A (en) * 1996-07-15 1999-11-09 Applied Materials, Inc. Wafer position error detection and correction system
US5835334A (en) * 1996-09-30 1998-11-10 Lam Research Variable high temperature chuck for high density plasma chemical vapor deposition
JP3245369B2 (ja) * 1996-11-20 2002-01-15 東京エレクトロン株式会社 被処理体を静電チャックから離脱する方法及びプラズマ処理装置
US5886864A (en) * 1996-12-02 1999-03-23 Applied Materials, Inc. Substrate support member for uniform heating of a substrate
TW325148U (en) * 1997-01-23 1998-01-11 Taiwan Semiconductor Mfg Co Ltd Temperature processing device
GB9711273D0 (en) 1997-06-03 1997-07-30 Trikon Equip Ltd Electrostatic chucks
US6075375A (en) * 1997-06-11 2000-06-13 Applied Materials, Inc. Apparatus for wafer detection
US6205870B1 (en) 1997-10-10 2001-03-27 Applied Komatsu Technology, Inc. Automated substrate processing systems and methods
US5901030A (en) * 1997-12-02 1999-05-04 Dorsey Gage, Inc. Electrostatic chuck employing thermoelectric cooling
US5872694A (en) * 1997-12-23 1999-02-16 Siemens Aktiengesellschaft Method and apparatus for determining wafer warpage for optimized electrostatic chuck clamping voltage
US5948986A (en) * 1997-12-26 1999-09-07 Applied Materials, Inc. Monitoring of wafer presence and position in semiconductor processing operations
US5886865A (en) * 1998-03-17 1999-03-23 Applied Materials, Inc. Method and apparatus for predicting failure of an eletrostatic chuck
US5969934A (en) * 1998-04-10 1999-10-19 Varian Semiconductor Equipment Associats, Inc. Electrostatic wafer clamp having low particulate contamination of wafers
TW432580B (en) * 1998-09-29 2001-05-01 Applied Materials Inc Piezoelectric method and apparatus for semiconductor wafer detection
US6113165A (en) * 1998-10-02 2000-09-05 Taiwan Semiconductor Manufacturing Co., Ltd. Self-sensing wafer holder and method of using
US6454332B1 (en) 1998-12-04 2002-09-24 Applied Materials, Inc. Apparatus and methods for handling a substrate
US6215640B1 (en) 1998-12-10 2001-04-10 Applied Materials, Inc. Apparatus and method for actively controlling surface potential of an electrostatic chuck
US6430022B2 (en) * 1999-04-19 2002-08-06 Applied Materials, Inc. Method and apparatus for controlling chucking force in an electrostatic
US6248642B1 (en) 1999-06-24 2001-06-19 Ibis Technology Corporation SIMOX using controlled water vapor for oxygen implants
US6155436A (en) * 1999-08-18 2000-12-05 Ibis Technology Corporation Arc inhibiting wafer holder assembly
US6423975B1 (en) 1999-08-18 2002-07-23 Ibis Technology, Inc. Wafer holder for simox processing
US6452195B1 (en) 1999-08-18 2002-09-17 Ibis Technology Corporation Wafer holding pin
US6433342B1 (en) 1999-08-18 2002-08-13 Ibis Technology Corporation Coated wafer holding pin
US6257001B1 (en) * 1999-08-24 2001-07-10 Lucent Technologies, Inc. Cryogenic vacuum pump temperature sensor
US6740853B1 (en) * 1999-09-29 2004-05-25 Tokyo Electron Limited Multi-zone resistance heater
DE60045384D1 (de) * 1999-09-29 2011-01-27 Tokyo Electron Ltd Mehrzonenwiderstandsheizung
US6362946B1 (en) 1999-11-02 2002-03-26 Varian Semiconductor Equipment Associates, Inc. Electrostatic wafer clamp having electrostatic seal for retaining gas
US6538873B1 (en) 1999-11-02 2003-03-25 Varian Semiconductor Equipment Associates, Inc. Active electrostatic seal and electrostatic vacuum pump
US6307728B1 (en) * 2000-01-21 2001-10-23 Applied Materials, Inc. Method and apparatus for dechucking a workpiece from an electrostatic chuck
JP4615670B2 (ja) * 2000-04-19 2011-01-19 アプライド マテリアルズ インコーポレイテッド 静電チャックにおけるチャッキング力を制御する方法及び装置
KR100344221B1 (ko) * 2000-09-22 2002-07-20 삼성전자 주식회사 웨이퍼 클램프 텐션 측정 장치
US6403322B1 (en) 2001-03-27 2002-06-11 Lam Research Corporation Acoustic detection of dechucking and apparatus therefor
US7073383B2 (en) * 2001-06-07 2006-07-11 Tokyo Electron Limited Apparatus and method for determining clamping status of semiconductor wafer
US6998353B2 (en) 2001-11-05 2006-02-14 Ibis Technology Corporation Active wafer cooling during damage engineering implant to enhance buried oxide formation in SIMOX wafers
US6710360B2 (en) 2002-07-10 2004-03-23 Axcelis Technologies, Inc. Adjustable implantation angle workpiece support structure for an ion beam implanter
US6900444B2 (en) * 2002-07-29 2005-05-31 Axcelis Technologies, Inc. Adjustable implantation angle workpiece support structure for an ion beam implanter
US6774373B2 (en) * 2002-07-29 2004-08-10 Axcelis Technologies, Inc. Adjustable implantation angle workpiece support structure for an ion beam implanter
US20040079289A1 (en) * 2002-10-23 2004-04-29 Kellerman Peter L. Electrostatic chuck wafer port and top plate with edge shielding and gas scavenging
US6740894B1 (en) 2003-02-21 2004-05-25 Axcelis Technologies, Inc. Adjustable implantation angle workpiece support structure for an ion beam implanter utilizing a linear scan motor
US20040187787A1 (en) * 2003-03-31 2004-09-30 Dawson Keith E. Substrate support having temperature controlled substrate support surface
US6828572B2 (en) * 2003-04-01 2004-12-07 Axcelis Technologies, Inc. Ion beam incident angle detector for ion implant systems
US6794664B1 (en) 2003-12-04 2004-09-21 Axcelis Technologies, Inc. Umbilical cord facilities connection for an ion beam implanter
US7245357B2 (en) * 2003-12-15 2007-07-17 Asml Netherlands B.V. Lithographic apparatus and device manufacturing method
US6987272B2 (en) * 2004-03-05 2006-01-17 Axcelis Technologies, Inc. Work piece transfer system for an ion beam implanter
US7697260B2 (en) * 2004-03-31 2010-04-13 Applied Materials, Inc. Detachable electrostatic chuck
US7030395B2 (en) * 2004-08-06 2006-04-18 Axcelis Technologies, Inc. Workpiece support structure for an ion beam implanter featuring spherical sliding seal vacuum feedthrough
US7982195B2 (en) * 2004-09-14 2011-07-19 Axcelis Technologies, Inc. Controlled dose ion implantation
US8226769B2 (en) * 2006-04-27 2012-07-24 Applied Materials, Inc. Substrate support with electrostatic chuck having dual temperature zones
US7629597B2 (en) * 2006-08-18 2009-12-08 Axcelis Technologies, Inc. Deposition reduction system for an ion implanter
US7993465B2 (en) * 2006-09-07 2011-08-09 Applied Materials, Inc. Electrostatic chuck cleaning during semiconductor substrate processing
US7986146B2 (en) * 2006-11-29 2011-07-26 Globalfoundries Inc. Method and system for detecting existence of an undesirable particle during semiconductor fabrication
US20090181475A1 (en) * 2008-01-11 2009-07-16 Novellus Systems, Inc. Detecting the presence of a workpiece relative to a carrier head
US7558045B1 (en) * 2008-03-20 2009-07-07 Novellus Systems, Inc. Electrostatic chuck assembly with capacitive sense feature, and related operating method
US7948734B2 (en) * 2008-09-11 2011-05-24 Tel Epion Inc. Electrostatic chuck power supply
US8169769B2 (en) * 2008-09-11 2012-05-01 Tel Epion Inc. Electrostatic chuck power supply
US8514544B2 (en) * 2009-08-07 2013-08-20 Trek, Inc. Electrostatic clamp optimizer
JP6151028B2 (ja) * 2013-01-17 2017-06-21 株式会社日立ハイテクノロジーズ 荷電粒子線装置
JP6066084B2 (ja) * 2013-12-11 2017-01-25 日新イオン機器株式会社 基板保持装置、半導体製造装置及び基板吸着判別方法
US9543110B2 (en) 2013-12-20 2017-01-10 Axcelis Technologies, Inc. Reduced trace metals contamination ion source for an ion implantation system
GB2540883B (en) 2014-02-07 2018-12-26 Trek Inc System and method for clamping a work piece
US20150357151A1 (en) 2014-06-10 2015-12-10 Axcelis Technologies, Inc. Ion implantation source with textured interior surfaces
JP6942936B2 (ja) * 2017-08-25 2021-09-29 株式会社アルバック 真空装置、吸着電源
JP7419288B2 (ja) * 2021-03-30 2024-01-22 キヤノントッキ株式会社 制御装置、成膜装置、制御方法、及び電子デバイスの製造方法
CN113984788B (zh) * 2021-12-24 2022-03-15 北京凯世通半导体有限公司 一种通过光学检测仪器对超低温离子注入设备监测的方法
US12435964B2 (en) 2023-11-16 2025-10-07 Tokyo Electron Limited Contactless capacitive measurement tool with improved throughput and accuracy
CN119008501B (zh) * 2024-10-21 2025-02-14 天津吉兆源科技有限公司 静电卡盘电源及控制方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6216540A (ja) * 1985-07-15 1987-01-24 Canon Inc ウエハ搬送装置
US5103367A (en) * 1987-05-06 1992-04-07 Unisearch Limited Electrostatic chuck using A.C. field excitation

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4184188A (en) * 1978-01-16 1980-01-15 Veeco Instruments Inc. Substrate clamping technique in IC fabrication processes
US4261762A (en) * 1979-09-14 1981-04-14 Eaton Corporation Method for conducting heat to or from an article being treated under vacuum
US4384918A (en) * 1980-09-30 1983-05-24 Fujitsu Limited Method and apparatus for dry etching and electrostatic chucking device used therein
GB2147459A (en) * 1983-09-30 1985-05-09 Philips Electronic Associated Electrostatic chuck for semiconductor wafers
US4692836A (en) * 1983-10-31 1987-09-08 Toshiba Kikai Kabushiki Kaisha Electrostatic chucks
US4733632A (en) * 1985-09-25 1988-03-29 Tokyo Electron Limited Wafer feeding apparatus
JPS63257481A (ja) * 1987-04-14 1988-10-25 Abisare:Kk 静電保持装置
EP0297227B1 (en) * 1987-04-14 1993-03-17 Abisare Co., Ltd. Machine unit having retaining device using static electricity
US4962441A (en) * 1989-04-10 1990-10-09 Applied Materials, Inc. Isolated electrostatic wafer blade clamp
US5173834A (en) * 1989-06-02 1992-12-22 Roland Dg Corporation Electrostatic attraction apparatus
EP0460954B1 (en) * 1990-06-08 1994-09-21 Varian Associates, Inc. Clamping a workpiece
US5325261A (en) * 1991-05-17 1994-06-28 Unisearch Limited Electrostatic chuck with improved release
US5315473A (en) * 1992-01-21 1994-05-24 Applied Materials, Inc. Isolated electrostatic chuck and excitation method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6216540A (ja) * 1985-07-15 1987-01-24 Canon Inc ウエハ搬送装置
US5103367A (en) * 1987-05-06 1992-04-07 Unisearch Limited Electrostatic chuck using A.C. field excitation

Also Published As

Publication number Publication date
CA2113290C (en) 1999-11-30
CA2113290A1 (en) 1994-07-16
DE69400113D1 (de) 1996-05-02
US5436790A (en) 1995-07-25
EP0607043B1 (en) 1996-03-27
JPH077073A (ja) 1995-01-10
EP0607043A1 (en) 1994-07-20
DE69400113T2 (de) 1996-10-24
TW231366B (enExample) 1994-10-01
KR940018947A (ko) 1994-08-19
JP3341221B2 (ja) 2002-11-05

Similar Documents

Publication Publication Date Title
KR100284663B1 (ko) 웨이퍼 감지 및 클램핑 모니터
KR100304241B1 (ko) 웨이퍼 방출 방법 및 장치
US5872694A (en) Method and apparatus for determining wafer warpage for optimized electrostatic chuck clamping voltage
US6121783A (en) Method and apparatus for establishing electrical contact between a wafer and a chuck
US5948986A (en) Monitoring of wafer presence and position in semiconductor processing operations
KR0167468B1 (ko) 비접촉 시트 저항 측정 방법 및 장치
JPS5979545A (ja) 静電チャック装置
WO1988009054A1 (en) Electrostatic chuck using ac field excitation
US6753964B2 (en) Axis determination apparatus, film-thickness measurement apparatus, deposition apparatus, axis determination method, and film-thickness measurement method
WO1999048148A1 (en) Method and apparatus for predicting failure of an electrostatic chuck
JP2014192405A (ja) プローブ装置
CN106165039B (zh) 用于夹紧工件的系统和方法
JP2000167467A (ja) ディスペンサ移動制御装置
JP2965176B2 (ja) 静電チャックの過渡特性評価方法
KR20000012030A (ko) 정전형척의성능변수를외부위치에서테스트하는장치및방법
JP3458548B2 (ja) ワーク電位の測定方法
US4282483A (en) Probe for determining p or n-type conductivity of semiconductor material
JPH10127072A (ja) 静電吸着装置、静電吸着力測定方法
JPH06198532A (ja) 静電チャック
JP2004063486A (ja) プローバのチャック機構
JP3897344B2 (ja) チャッキング状態検出方法及びプラズマ処理装置
JP3980295B2 (ja) ワーク搬送装置
JPH0653294A (ja) プロービング装置
CN109668650B (zh) 用于热刺激电流法的检测装置
JP2002148297A (ja) 誘導電位測定方法と装置

Legal Events

Date Code Title Description
PA0109 Patent application

Patent event code: PA01091R01D

Comment text: Patent Application

Patent event date: 19940112

PG1501 Laying open of application
A201 Request for examination
PA0201 Request for examination

Patent event code: PA02012R01D

Patent event date: 19970827

Comment text: Request for Examination of Application

Patent event code: PA02011R01I

Patent event date: 19940112

Comment text: Patent Application

E902 Notification of reason for refusal
PE0902 Notice of grounds for rejection

Comment text: Notification of reason for refusal

Patent event date: 20000203

Patent event code: PE09021S01D

N231 Notification of change of applicant
PN2301 Change of applicant

Patent event date: 20000816

Comment text: Notification of Change of Applicant

Patent event code: PN23011R01D

E701 Decision to grant or registration of patent right
PE0701 Decision of registration

Patent event code: PE07011S01D

Comment text: Decision to Grant Registration

Patent event date: 20001006

GRNT Written decision to grant
PR0701 Registration of establishment

Comment text: Registration of Establishment

Patent event date: 20001221

Patent event code: PR07011E01D

PR1002 Payment of registration fee

Payment date: 20001222

End annual number: 3

Start annual number: 1

PG1601 Publication of registration
PR1001 Payment of annual fee

Payment date: 20031106

Start annual number: 4

End annual number: 4

PR1001 Payment of annual fee

Payment date: 20041018

Start annual number: 5

End annual number: 5

PR1001 Payment of annual fee

Payment date: 20051014

Start annual number: 6

End annual number: 6

PR1001 Payment of annual fee

Payment date: 20061020

Start annual number: 7

End annual number: 7

PR1001 Payment of annual fee

Payment date: 20071011

Start annual number: 8

End annual number: 8

PR1001 Payment of annual fee

Payment date: 20081014

Start annual number: 9

End annual number: 9

PR1001 Payment of annual fee

Payment date: 20091016

Start annual number: 10

End annual number: 10

PR1001 Payment of annual fee

Payment date: 20101129

Start annual number: 11

End annual number: 11

PR1001 Payment of annual fee

Payment date: 20111129

Start annual number: 12

End annual number: 12

FPAY Annual fee payment

Payment date: 20121129

Year of fee payment: 13

PR1001 Payment of annual fee

Payment date: 20121129

Start annual number: 13

End annual number: 13

FPAY Annual fee payment

Payment date: 20131129

Year of fee payment: 14

PR1001 Payment of annual fee

Payment date: 20131129

Start annual number: 14

End annual number: 14

EXPY Expiration of term
PC1801 Expiration of term

Termination date: 20140712

Termination category: Expiration of duration