TW348089B - Method and system of monitoring a process of removing material from an article - Google Patents

Method and system of monitoring a process of removing material from an article

Info

Publication number
TW348089B
TW348089B TW086100647A TW86100647A TW348089B TW 348089 B TW348089 B TW 348089B TW 086100647 A TW086100647 A TW 086100647A TW 86100647 A TW86100647 A TW 86100647A TW 348089 B TW348089 B TW 348089B
Authority
TW
Taiwan
Prior art keywords
article
monitoring
moving
processing status
removing material
Prior art date
Application number
TW086100647A
Other languages
English (en)
Inventor
H Sun Mei
E Litvak Herbert
M Tzenn Huey
E Glenn Daniel
M Jensen Earl
J Hausman Frank
Jun Zhou Lin
Original Assignee
Luxtron Corp
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 Luxtron Corp filed Critical Luxtron Corp
Application granted granted Critical
Publication of TW348089B publication Critical patent/TW348089B/zh

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B37/00—Lapping machines or devices; Accessories
    • B24B37/005—Control means for lapping machines or devices
    • B24B37/013—Devices or means for detecting lapping completion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
    • B24B49/02—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation according to the instantaneous size and required size of the workpiece acted upon, the measuring or gauging being continuous or intermittent
    • B24B49/04—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation according to the instantaneous size and required size of the workpiece acted upon, the measuring or gauging being continuous or intermittent involving measurement of the workpiece at the place of grinding during grinding operation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
    • B24B49/12—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation involving optical means
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00—Programme-control systems
    • G05B19/02—Programme-control systems electric
    • G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
    • G05B19/406—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by monitoring or safety
    • G05B19/4065—Monitoring tool breakage, life or condition

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Human Computer Interaction (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
TW086100647A 1996-01-11 1997-01-22 Method and system of monitoring a process of removing material from an article TW348089B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US08/585,164 US6010538A (en) 1996-01-11 1996-01-11 In situ technique for monitoring and controlling a process of chemical-mechanical-polishing via a radiative communication link

Publications (1)

Publication Number Publication Date
TW348089B true TW348089B (en) 1998-12-21

Family

ID=24340295

Family Applications (1)

Application Number Title Priority Date Filing Date
TW086100647A TW348089B (en) 1996-01-11 1997-01-22 Method and system of monitoring a process of removing material from an article

Country Status (4)

Country Link
US (1) US6010538A (zh)
EP (1) EP0873544A1 (zh)
TW (1) TW348089B (zh)
WO (1) WO1997025660A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI758323B (zh) * 2016-09-15 2022-03-21 美商應用材料股份有限公司 化學機械拋光智慧環及使用該化學機械拋光智慧環的化學機械拋光系統與方法

Families Citing this family (99)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6261152B1 (en) * 1998-07-16 2001-07-17 Nikon Research Corporation Of America Heterdoyne Thickness Monitoring System
US6352466B1 (en) * 1998-08-31 2002-03-05 Micron Technology, Inc. Method and apparatus for wireless transfer of chemical-mechanical planarization measurements
TW414964B (en) * 1998-09-23 2000-12-11 United Microelectronics Corp Method of reducing noise of end point detector in chemical mechanical polishing process
WO2000036543A1 (en) * 1998-12-16 2000-06-22 University Of Massachusetts Grinding wheel system
US6994607B2 (en) * 2001-12-28 2006-02-07 Applied Materials, Inc. Polishing pad with window
US20040082271A1 (en) * 1999-01-25 2004-04-29 Wiswesser Andreas Norbert Polishing pad with window
US6247998B1 (en) * 1999-01-25 2001-06-19 Applied Materials, Inc. Method and apparatus for determining substrate layer thickness during chemical mechanical polishing
US6309555B1 (en) * 1999-03-01 2001-10-30 United Microelectronics Corp. Method for determining thickness of material layer and chemical mechanical polishing endpoint
AU4034200A (en) * 1999-03-26 2000-10-16 Speed-Fam-Ipec Corporation Optical endpoint detection system for rotational chemical mechanical polishing
US6476604B1 (en) * 1999-04-12 2002-11-05 Chartered Semiconductor Manufacturing Ltd. Method and apparatus for identifying high metal content on a semiconductor surface
WO2000071971A1 (en) 1999-05-24 2000-11-30 Luxtron Corporation Optical techniques for measuring layer thicknesses
US6570662B1 (en) 1999-05-24 2003-05-27 Luxtron Corporation Optical techniques for measuring layer thicknesses and other surface characteristics of objects such as semiconductor wafers
US6437868B1 (en) * 1999-10-28 2002-08-20 Agere Systems Guardian Corp. In-situ automated contactless thickness measurement for wafer thinning
US6635512B1 (en) * 1999-11-04 2003-10-21 Rohm Co., Ltd. Method of producing a semiconductor device by dividing a semiconductor wafer into separate pieces of semiconductor chips
JP3684972B2 (ja) * 2000-01-13 2005-08-17 Ｔｄｋ株式会社 加工装置および方法
US6383058B1 (en) * 2000-01-28 2002-05-07 Applied Materials, Inc. Adaptive endpoint detection for chemical mechanical polishing
US6340326B1 (en) * 2000-01-28 2002-01-22 Lam Research Corporation System and method for controlled polishing and planarization of semiconductor wafers
US6705930B2 (en) * 2000-01-28 2004-03-16 Lam Research Corporation System and method for polishing and planarizing semiconductor wafers using reduced surface area polishing pads and variable partial pad-wafer overlapping techniques
WO2001074532A1 (en) * 2000-03-30 2001-10-11 Memc Electronic Materials, S.P.A. Method of polishing wafers
US6485354B1 (en) * 2000-06-09 2002-11-26 Strasbaugh Polishing pad with built-in optical sensor
FR2810915B1 (fr) * 2000-07-03 2002-10-04 St Microelectronics Sa Procede de determination de la duree de polissage de la surface d'une plaquette de circuits integres
US6338668B1 (en) 2000-08-16 2002-01-15 Taiwan Semiconductor Manufacturing Company, Ltd In-line chemical mechanical polish (CMP) planarizing method employing interpolation and extrapolation
US7127362B2 (en) * 2000-08-22 2006-10-24 Mundt Randall S Process tolerant methods and apparatus for obtaining data
US6257953B1 (en) * 2000-09-25 2001-07-10 Center For Tribology, Inc. Method and apparatus for controlled polishing
WO2002026445A1 (en) * 2000-09-29 2002-04-04 Strasbaugh, Inc. Polishing pad with built-in optical sensor
AU2001291143A1 (en) * 2000-10-06 2002-04-22 Cabot Microelectronics Corporation Polishing pad comprising a filled translucent region
US6524959B1 (en) * 2000-10-10 2003-02-25 Taiwan Semiconductor Manufacturing Co., Ltd. Chemical mechanical polish (CMP) planarizing method employing derivative signal end-point monitoring and control
US6517413B1 (en) 2000-10-25 2003-02-11 Taiwan Semiconductor Manufacturing Company Method for a copper CMP endpoint detection system
WO2002047530A1 (en) * 2000-12-15 2002-06-20 Johnsondiversey, Inc. Device for monitoring a wash process
US7302186B2 (en) 2001-02-05 2007-11-27 Finisar Corporation Optical transceiver and host adapter with memory mapped monitoring circuitry
US6912361B2 (en) * 2002-10-08 2005-06-28 Finisar Corporation Optical transceiver module with multipurpose internal serial bus
US7346278B2 (en) * 2001-02-05 2008-03-18 Finisar Corporation Analog to digital signal conditioning in optoelectronic transceivers
US7079775B2 (en) 2001-02-05 2006-07-18 Finisar Corporation Integrated memory mapped controller circuit for fiber optics transceiver
US20040197101A1 (en) * 2001-02-05 2004-10-07 Sasser Gary D. Optical transceiver module with host accessible on-board diagnostics
US7149430B2 (en) * 2001-02-05 2006-12-12 Finsiar Corporation Optoelectronic transceiver having dual access to onboard diagnostics
US6849859B2 (en) * 2001-03-21 2005-02-01 Euv Limited Liability Corporation Fabrication of precision optics using an imbedded reference surface
JP2002289614A (ja) * 2001-03-26 2002-10-04 Nec Corp 誘電体膜の評価方法、熱処理装置の温度校正方法及び半導体記憶装置の製造方法
US7282889B2 (en) * 2001-04-19 2007-10-16 Onwafer Technologies, Inc. Maintenance unit for a sensor apparatus
US6491569B2 (en) 2001-04-19 2002-12-10 Speedfam-Ipec Corporation Method and apparatus for using optical reflection data to obtain a continuous predictive signal during CMP
JP4041797B2 (ja) 2001-06-28 2008-01-30 ポラック ラボラトリーズ インコーポレイテッド 内蔵型センサ装置
US6579150B2 (en) * 2001-07-05 2003-06-17 Taiwan Semiconductor Manufacturing Co., Ltd Dual detection method for end point in chemical mechanical polishing
US6618130B2 (en) 2001-08-28 2003-09-09 Speedfam-Ipec Corporation Method and apparatus for optical endpoint detection during chemical mechanical polishing
US6977184B1 (en) * 2001-10-31 2005-12-20 Lam Research Corporation Method and apparatus for nitride spacer etch process implementing in situ interferometry endpoint detection and non-interferometry endpoint monitoring
US7757574B2 (en) * 2002-01-24 2010-07-20 Kla-Tencor Corporation Process condition sensing wafer and data analysis system
US6889568B2 (en) * 2002-01-24 2005-05-10 Sensarray Corporation Process condition sensing wafer and data analysis system
US6935922B2 (en) 2002-02-04 2005-08-30 Kla-Tencor Technologies Corp. Methods and systems for generating a two-dimensional map of a characteristic at relative or absolute locations of measurement spots on a specimen during polishing
JP2003266305A (ja) * 2002-03-15 2003-09-24 Seiko Instruments Inc 端面研磨装置及び端面研磨方法
US7151366B2 (en) * 2002-12-03 2006-12-19 Sensarray Corporation Integrated process condition sensing wafer and data analysis system
US7135852B2 (en) * 2002-12-03 2006-11-14 Sensarray Corporation Integrated process condition sensing wafer and data analysis system
US20040126906A1 (en) * 2002-12-31 2004-07-01 Tokyo Electron Limited Method and apparatus for monitoring a material processing system
US20040127030A1 (en) * 2002-12-31 2004-07-01 Tokyo Electron Limited Method and apparatus for monitoring a material processing system
US20040127031A1 (en) * 2002-12-31 2004-07-01 Tokyo Electron Limited Method and apparatus for monitoring a plasma in a material processing system
US7403834B2 (en) * 2003-05-08 2008-07-22 Regents Of The University Of California Methods of and apparatuses for controlling process profiles
US7215891B1 (en) 2003-06-06 2007-05-08 Jds Uniphase Corporation Integrated driving, receiving, controlling, and monitoring for optical transceivers
JP2007528585A (ja) * 2003-06-13 2007-10-11 株式会社荏原製作所 測定装置
US7413988B1 (en) * 2003-06-27 2008-08-19 Lam Research Corporation Method and apparatus for detecting planarization of metal films prior to clearing
US7415312B2 (en) * 2004-05-25 2008-08-19 Barnett Jr James R Process module tuning
US7052364B2 (en) * 2004-06-14 2006-05-30 Cabot Microelectronics Corporation Real time polishing process monitoring
US7198549B2 (en) * 2004-06-16 2007-04-03 Cabot Microelectronics Corporation Continuous contour polishing of a multi-material surface
US7363195B2 (en) * 2004-07-07 2008-04-22 Sensarray Corporation Methods of configuring a sensor network
US7120553B2 (en) * 2004-07-22 2006-10-10 Applied Materials, Inc. Iso-reflectance wavelengths
US7504610B2 (en) * 2004-09-03 2009-03-17 Mindspeed Technologies, Inc. Optical modulation amplitude compensation system having a laser driver with modulation control signals
US7722434B2 (en) 2005-03-29 2010-05-25 Kla-Tencor Corporation Apparatus for measurement of parameters in process equipment
US8604361B2 (en) * 2005-12-13 2013-12-10 Kla-Tencor Corporation Component package for maintaining safe operating temperature of components
US7494929B2 (en) * 2006-04-27 2009-02-24 Applied Materials, Inc. Automatic gain control
US7540188B2 (en) * 2006-05-01 2009-06-02 Lynn Karl Wiese Process condition measuring device with shielding
US7555948B2 (en) * 2006-05-01 2009-07-07 Lynn Karl Wiese Process condition measuring device with shielding
US20080078948A1 (en) * 2006-10-03 2008-04-03 Tokyo Electron Limited Processing termination detection method and apparatus
US7698952B2 (en) * 2006-10-03 2010-04-20 Kla-Tencor Corporation Pressure sensing device
US8750341B2 (en) * 2008-01-04 2014-06-10 Mindspeed Technologies, Inc. Method and apparatus for reducing optical signal speckle
CN102318338A (zh) 2008-03-31 2012-01-11 曼德斯必德技术公司 便携式lcos/lcd/dlp投影系统中的功率耗散的减少
FR2930824B1 (fr) * 2008-04-30 2015-04-24 Commissariat Energie Atomique Procede de mesure d'un tenseur anisotrope de diffusion de surface ou des anisotropies de l'energie de surface
US8159956B2 (en) 2008-07-01 2012-04-17 Finisar Corporation Diagnostics for serial communication busses
US8989890B2 (en) * 2008-11-07 2015-03-24 Applied Materials, Inc. GST film thickness monitoring
US8639377B2 (en) * 2008-11-07 2014-01-28 Applied Materials, Inc. Metrology for GST film thickness and phase
US8793102B2 (en) * 2010-01-12 2014-07-29 Baker Hughes Incorporated Multi-gap interferometric sensors
US8643296B2 (en) 2010-11-22 2014-02-04 Mindspeed Technologies, Inc. Color mixing and desaturation with reduced number of converters
US8681493B2 (en) 2011-05-10 2014-03-25 Kla-Tencor Corporation Heat shield module for substrate-like metrology device
US9107245B2 (en) 2011-06-09 2015-08-11 Mindspeed Technologies, Inc. High accuracy, high dynamic range LED/laser driver
DE102011080192A1 (de) * 2011-08-01 2013-02-07 Raumedic Ag Verfahren und Vorrichtung zur Übertragung von Sensordaten eines implantierbaren Sensors auf ein externes datenverarbeitendes Gerät
US20140020829A1 (en) * 2012-07-18 2014-01-23 Applied Materials, Inc. Sensors in Carrier Head of a CMP System
US20140120802A1 (en) * 2012-10-31 2014-05-01 Wayne O. Duescher Abrasive platen wafer surface optical monitoring system
US9385606B2 (en) 2012-12-03 2016-07-05 M/A-Com Technology Solutions Holdings, Inc. Automatic buck/boost mode selection system for DC-DC converter
US20140224425A1 (en) * 2013-02-13 2014-08-14 Kabushiki Kaisha Toshiba Film thickness monitoring method, film thickness monitoring device, and semiconductor manufacturing apparatus
US20140242877A1 (en) * 2013-02-26 2014-08-28 Applied Materials, Inc. Spectrographic metrology with multiple measurements
US9878421B2 (en) * 2014-06-16 2018-01-30 Applied Materials, Inc. Chemical mechanical polishing retaining ring with integrated sensor
US10097908B2 (en) 2014-12-31 2018-10-09 Macom Technology Solutions Holdings, Inc. DC-coupled laser driver with AC-coupled termination element
KR101870701B1 (ko) * 2016-08-01 2018-06-25 에스케이실트론 주식회사 폴리싱 측정 장치 및 그의 연마 시간 제어 방법, 및 그를 포함한 폴리싱 제어 시스템
TWI750216B (zh) 2016-08-30 2021-12-21 美商Ｍａｃｏｍ技術方案控股公司 具分散式架構之驅動器
US10630052B2 (en) 2017-10-04 2020-04-21 Macom Technology Solutions Holdings, Inc. Efficiency improved driver for laser diode in optical communication
US11565365B2 (en) * 2017-11-13 2023-01-31 Taiwan Semiconductor Manufacturing Co., Ltd. System and method for monitoring chemical mechanical polishing
CN108972376B (zh) * 2018-07-04 2020-12-01 郑州磨料磨具磨削研究所有限公司 一种物联网砂轮
CN109333360B (zh) * 2018-10-15 2020-07-03 北京工业大学 一种晶圆减薄磨削力在线测量装置及方法
US11005573B2 (en) 2018-11-20 2021-05-11 Macom Technology Solutions Holdings, Inc. Optic signal receiver with dynamic control
US11575437B2 (en) 2020-01-10 2023-02-07 Macom Technology Solutions Holdings, Inc. Optimal equalization partitioning
CN115191090B (zh) 2020-01-10 2024-06-14 Macom技术解决方案控股公司 最佳均衡划分
US12013423B2 (en) 2020-09-30 2024-06-18 Macom Technology Solutions Holdings, Inc. TIA bandwidth testing system and method
US11658630B2 (en) 2020-12-04 2023-05-23 Macom Technology Solutions Holdings, Inc. Single servo loop controlling an automatic gain control and current sourcing mechanism
US11616529B2 (en) 2021-02-12 2023-03-28 Macom Technology Solutions Holdings, Inc. Adaptive cable equalizer

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5190614A (en) * 1990-09-05 1993-03-02 Luxtron Corporation Method of endpoint detection and structure therefor
US5308447A (en) * 1992-06-09 1994-05-03 Luxtron Corporation Endpoint and uniformity determinations in material layer processing through monitoring multiple surface regions across the layer
WO1993025893A1 (en) * 1992-06-09 1993-12-23 Luxtron Corporation Endpoint detection technique using signal slope determinations
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
US5362969A (en) * 1993-04-23 1994-11-08 Luxtron Corporation Processing endpoint detecting technique and detector structure using multiple radiation sources or discrete detectors
US5700180A (en) * 1993-08-25 1997-12-23 Micron Technology, Inc. System for real-time control of semiconductor wafer polishing
US5433651A (en) * 1993-12-22 1995-07-18 International Business Machines Corporation In-situ endpoint detection and process monitoring method and apparatus for chemical-mechanical polishing
US5461007A (en) * 1994-06-02 1995-10-24 Motorola, Inc. Process for polishing and analyzing a layer over a patterned semiconductor substrate
US5483568A (en) * 1994-11-03 1996-01-09 Kabushiki Kaisha Toshiba Pad condition and polishing rate monitor using fluorescence
US5685766A (en) * 1995-11-30 1997-11-11 Speedfam Corporation Polishing control method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI758323B (zh) * 2016-09-15 2022-03-21 美商應用材料股份有限公司 化學機械拋光智慧環及使用該化學機械拋光智慧環的化學機械拋光系統與方法

Also Published As

Publication number Publication date
US6010538A (en) 2000-01-04
WO1997025660A1 (en) 1997-07-17
EP0873544A1 (en) 1998-10-28

Similar Documents

Publication Publication Date Title
TW348089B (en) Method and system of monitoring a process of removing material from an article
GB2320089B (en) Detection system for determining positional and other information about objects
DE60026750D1 (de) Verfahren, Vorrichtung und System zur Übertragung von optischen Überwachungssignalen
EP1229672A3 (en) Optical data communication and location apparatus
WO2000036543A8 (en) Grinding wheel system
NO975970D0 (no) Fremgangsmåte for sending av komprimenterte seismiske data
EP0866589A4 (en) DATA TRANSMISSION METHOD, DATA TRANSMISSION SYSTEM, AND RECEIVER
NO960860D0 (no) Fremgangsmåte for mottaking, samt mottaker
EP0935355A3 (en) A system and method for monitoring and characterizing optical links
EP0923247A3 (en) Information broadcasting method, receiver and information processing apparatus
GB2313193B (en) Method and apparatus for distance measurement
EP0834846A3 (de) Drahtlose Gefahren-Meldeanlage und Meldeverfahren
TR200002556T2 (tr) Veri iletişim sistemi
EP0844751A3 (en) Optical transmitter, terminal-station apparatus having the optical transmitter and optical communication system, monitoring the optical transmitted signal
HK1039852A1 (en) Signal transmitting and receiving apparatus, system and method
EP0898151A3 (en) Method and arrangement for configuring a measuring device
HK1030129A1 (en) Method, apparatus and system for processing an audio signal.
AU3240095A (en) Real-time signal processing system for serially transmitted data
EP1168683A3 (en) Method and system for supervision of an optical amplifier repeater system
EP0632597A3 (en) Apparatus and method for audio signal transmission.
EP1122933A3 (en) Transmitting apparatus, receiving apparatus, transmitting-receiving system, transmitting method, and receiving method
TW357506B (en) Systems and methods for communicating desired audio information over a communications medium
BR9711894B1 (pt) processo para transmitir um sinal de áudio entre uma unidade transmissora de áudio e uma unidade receptora de áudio, e, sistema de transmissão de sinal de áudio de multi-resolução.
ATE211844T1 (de) Verfahren und vorrichtung zur fernüberwachung von in einem raum abgelegten gegenständen
AU1452395A (en) Process for finding the receivability of radio signals in a radio system