CN104701200B - A kind of device of on-line real-time measuremen epitaxial wafer temperature - Google Patents

A kind of device of on-line real-time measuremen epitaxial wafer temperature Download PDF

Info

Publication number
CN104701200B
CN104701200B CN201310651770.8A CN201310651770A CN104701200B CN 104701200 B CN104701200 B CN 104701200B CN 201310651770 A CN201310651770 A CN 201310651770A CN 104701200 B CN104701200 B CN 104701200B
Authority
CN
China
Prior art keywords
epitaxial wafer
reflectivity
plated film
computing module
chamber window
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.)
Active
Application number
CN201310651770.8A
Other languages
Chinese (zh)
Other versions
CN104701200A (en
Inventor
马铁中
严冬
王林梓
刘健鹏
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Beijing Airui Haotai Information Technology Co ltd
Original Assignee
BEI OPITCS TECHNOLOGY Co Ltd
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 BEI OPITCS TECHNOLOGY Co Ltd filed Critical BEI OPITCS TECHNOLOGY Co Ltd
Priority to CN201310651770.8A priority Critical patent/CN104701200B/en
Publication of CN104701200A publication Critical patent/CN104701200A/en
Application granted granted Critical
Publication of CN104701200B publication Critical patent/CN104701200B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
    • H01L22/10—Measuring as part of the manufacturing process
    • H01L22/12—Measuring as part of the manufacturing process for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00

Abstract

The invention discloses a kind of device of on-line real-time measuremen epitaxial wafer temperature, belong to semiconductor detection technique field.The device includes black body radiation value computing module and temperature computing module, and the device can obtain the temperature T of epitaxial wafer by introducing the reflectivity decay factor and the thermal radiant attenuation factor of plated film window with accurate measurement.The device can elimination reaction chamber window plated film influenceed to caused by online real time temperature detected value, improve the online real time temperature detected value degree of accuracy.

Description

A kind of device of on-line real-time measuremen epitaxial wafer temperature
Technical field
The present invention relates to semiconductor detection technique field, more particularly to a kind of dress of on-line real-time measuremen epitaxial wafer temperature Put.
Background technology
Temperature is a crucial inspection during chemical vapor deposition (CVD), molecular beam epitaxy (MBE) homepitaxy blade technolgy Survey factor.For strict reaction condition, such as active environment of high vacuum, high temperature, chemical property, the substrate of rotation at a high speed, Temperature progress directly detection to epitaxial wafer is nearly impossible.Therefore, in order to enhance product performance, reduce production cost, Optimize technique controls, and prior art is typically to use a kind of optics on-line detecting system, using the optics thermometric based on heat radiation Technology, the epitaxial wafer temperature in epitaxial wafer growth course is detected in real time.
But during using this optics on-line detecting system, while extension length of a film film, reaction chamber window can plate one Layer or multilayer supplement film, and had a great influence based on the optical measurement technology of heat radiation by window plated film, cause epitaxial wafer temperature Deviation between actual value and detected value can reach 10 DEG C.Window, which is cleared up, or changed can reduce epitaxial wafer temperature reality Be worth detected value between deviation, still, window is cleared up or changed can to processing line bring huge time cost and Goods and materials cost.
The content of the invention
In order to solve the above problems, it is to be introduced in the online real time temperature measurement technology based on heat radiation that the present invention, which proposes a kind of, Reflectivity decay factor and the thermal radiant attenuation factor, so as to which elimination reaction chamber window plated film causes to online real time temperature detected value Influence, improve the online real time temperature detected value degree of accuracy on-line real-time measuremen epitaxial wafer temperature device.
The device of on-line real-time measuremen epitaxial wafer temperature provided by the invention includes black body radiation value computing module and temperature Computing module；
The black body radiation value computing module according toObtain Pb(λ, T),
Wherein,
Pb(λ, T), black body radiation value,
L (λ, T), the caloradiance of epitaxial wafer,
R, the reflectivity of epitaxial wafer,
ΔTT, the thermal radiant attenuation factor caused by reaction chamber window plated film,
ΔTR, reflectivity decay factor caused by reaction chamber window plated film,
ε(R/ΔTR), the thermal emissivity of epitaxial wafer,
The temperature computing module according toThe temperature T of the epitaxial wafer is obtained,
Wherein,
Pb(λ, T), ideal black-body radiation value,
H, Planck's constant,
K, Boltzmann constant,
C, the light velocity,
λ, wavelength,
T, temperature.
The device of on-line real-time measuremen epitaxial wafer temperature provided by the invention, the reaction chamber window for epitaxial wafer can be obtained Thermal radiant attenuation factor Δ T caused by mouth plated filmTWith reaction chamber window plated film caused by reflectivity decay factor Δ TR, by this two Individual decay factor Δ TTWith Δ TRIt is applied in the calculating process of black body radiation value, and utilizes black body radiation value and the temperature of epitaxial wafer Relation between degree calculates temperature, you can elimination reaction chamber window plated film influences to caused by online real time temperature detected value, carried The high online real time temperature detected value degree of accuracy.
Brief description of the drawings
Fig. 1 is the principle sketch of the device for the on-line real-time measuremen epitaxial wafer temperature that the embodiment of the present invention one provides；
Fig. 2 is the principle sketch of the device for the on-line real-time measuremen epitaxial wafer temperature that the embodiment of the present invention two provides.
Embodiment
In order to understand the present invention in depth, below in conjunction with the accompanying drawings and specific embodiment the present invention is described in detail.
Referring to accompanying drawing 1, the device of on-line real-time measuremen epitaxial wafer temperature provided by the invention includes black body radiation value computing Module and temperature computing module, the temperature computing module are calculated according to the result of the black body radiation value computing module The temperature of epitaxial wafer；
The black body radiation value computing module according toObtain Pb(λ, T),
Wherein,
Pb(λ, T), black body radiation value,
L (λ, T), the caloradiance of epitaxial wafer,
R, the reflectivity of epitaxial wafer,
ΔTT, the thermal radiant attenuation factor caused by reaction chamber window plated film,
ΔTR, reflectivity decay factor caused by reaction chamber window plated film,
ε(R/ΔTR), the thermal emissivity of epitaxial wafer,
The temperature computing module according toThe temperature T of the epitaxial wafer is obtained,
Wherein,
Pb(λ, T), ideal black-body radiation value,
H, Planck's constant,
K, Boltzmann constant,
C, the light velocity,
λ, wavelength,
T, temperature.
The device of on-line real-time measuremen epitaxial wafer temperature provided by the invention, the reaction chamber window for epitaxial wafer can be obtained Thermal radiant attenuation factor Δ T caused by mouth plated filmTWith reaction chamber window plated film caused by reflectivity decay factor Δ TR, by this two Individual decay factor Δ TTWith Δ TRIn the calculating process for the black body radiation value being applied to, and utilize black body radiation value and epitaxial wafer Relation between temperature calculates temperature, you can elimination reaction chamber window plated film influences to caused by online real time temperature detected value, Improve the online real time temperature detected value degree of accuracy.
Embodiment two
Referring to accompanying drawing 2, the device for the on-line real-time measuremen epitaxial wafer temperature that the embodiment of the present invention two provides includes beam intensity ratio Rate computing module, data acquisition module, reflectivity computing module, reflectivity decay factor computing module, the choosing of thermal emissivity function Select module, thermal radiant attenuation factor computing module, black body radiation value computing module and temperature computing module.The light intensity ratio fortune Calculate module and obtain the light intensity ratio m of reference light and incident light by computing.The data acquisition module is used to gather epitaxial wafer Intensity of reflected light IInstead, epitaxial wafer reference light intensity IGinsengWith the caloradiance L (λ, T) of epitaxial wafer.Reflectivity computing module connects Receive the intensity of reflected light I of the operation result of light intensity ratio computing module and the epitaxial wafer of data collecting module collectedInsteadAnd epitaxial wafer Reference light intensity IGinseng, by computing, obtain reflectivity R.Reflectivity decay factor computing module receives reflectivity computing module Operation result after by computing obtain reflectivity decay factor Δ TR.Thermal emissivity function selecting module is first according to reaction chamber Window plated film is selected thermal emissivity function, so receive reflectivity computing module operation result and reflectivity decay because The operation result of sub- computing module, thermal emissivity ε (R/ Δs T are obtained by computingR).Thermal radiant attenuation factor computing module receives The operation result of reflectivity decay factor computing module, thermal radiant attenuation factor Δ T is obtained by computingR.Black body radiation value is transported The caloradiance L (λ, T) that module receives the epitaxial wafer of data collecting module collected is calculated, and receives reflectivity decay factor computing The operation result of module, the operation result of thermal emissivity function selecting module, the computing knot of thermal radiant attenuation factor computing module Fruit, black body radiation value P is obtained by computingb(λ, T).Temperature computing module receives the computing knot of black body radiation value computing module Fruit, the temperature T of epitaxial wafer is obtained by computing.
The operational formula difference that above-mentioned each module performs is as follows：
Light intensity ratio computing module according toThe light intensity ratio m of reference light and incident light is obtained,
Wherein,
RStandard, the reflectivity of the epitaxial wafer with standard reflectivity,
The light intensity ratio of m, reference light and incident light,
IInstead, the intensity of reflected light of epitaxial wafer,
IGinseng, the reference light intensity of epitaxial wafer.
Reflectivity computing module according toThe reflectivity R of epitaxial wafer is obtained,
Wherein,
R, the reflectivity of epitaxial wafer,
The light intensity ratio of m, reference light and incident light,
IInstead, the intensity of reflected light of epitaxial wafer,
IGinseng, the reference light intensity of epitaxial wafer.
Reflectivity decay factor computing module according toReflectivity caused by reaction chamber window plated film is obtained to decay Factor Δ TR,
Wherein,
ΔTR, reflectivity decay factor caused by reaction chamber window plated film,
R, the reflectivity of epitaxial wafer,
R0, the ideal reflectivity of epitaxial wafer.
Thermal radiant attenuation factor computing module according toHeat radiation caused by obtaining reaction chamber window plated film declines Subtracting coefficient Δ TT,
Wherein,
ΔTT, the thermal radiant attenuation factor caused by reaction chamber window plated film,
ΔTR, reflectivity decay factor caused by reaction chamber window plated film.
When reaction chamber window plated film is opaque, smooth ideal, even curface, thermal emissivity function selecting module root According to ε (R/ Δs TR)=1-R/ Δs TRObtain ε (R/ Δs TR),
Wherein,
R, the reflectivity of epitaxial wafer,
ΔTR, reflectivity decay factor caused by reaction chamber window plated film,
ε(R/ΔTR), the thermal emissivity of epitaxial wafer.
When reaction chamber window plated film polishes for transparent, one side substrate, thermal emissivity function selecting module is according to ε (R/ Δs TR)=εcarr(1-R/ΔTR)(1-Rdiff){1+R/ΔTR*Rdiff+(1-εcarr)[(Rdiff+R/ΔTR(1-Rdiff)2)] obtain ε (R/ΔTR),
Wherein,
ε(R/ΔTR), the thermal emissivity of epitaxial wafer,
R, the reflectivity of epitaxial wafer,
Rdiff, the scattered power of unsmooth substrate,
εcarr, the thermal emissivity of graphite base,
ΔTR, reflectivity decay factor caused by reaction chamber window plated film.
Black body radiation value computing module according toObtain Pb(λ, T),
Wherein,
Pb(λ, T), black body radiation value,
L (λ, T), the caloradiance of epitaxial wafer,
R, the reflectivity of epitaxial wafer,
ΔTT, the thermal radiant attenuation factor caused by reaction chamber window plated film,
ΔTR, reflectivity decay factor caused by reaction chamber window plated film,
ε(R/ΔTR), the thermal emissivity of epitaxial wafer,
Temperature computing module according toThe temperature T of epitaxial wafer is obtained,
Wherein,
Pb(λ, T), ideal black-body radiation value,
H, Planck's constant,
K, Boltzmann constant,
C, the light velocity,
λ, wavelength,
T, temperature.
Compared with the device for the on-line real-time measuremen epitaxial wafer temperature that the embodiment of the present invention one provides, the embodiment of the present invention two The device of the on-line real-time measuremen epitaxial wafer temperature of offer from data acquisition to each calculation step using modularization automatically from Reason, further improves the computing degree of accuracy and operation efficiency.
Above-described embodiment, the purpose of the present invention, technical scheme and beneficial effect are carried out further Describe in detail, should be understood that the embodiment that the foregoing is only the present invention, be not limited to this hair It is bright, within the spirit and principles of the invention, any modification, equivalent substitution and improvements done etc., it should be included in the present invention Protection domain within.

Claims (9)

  1. A kind of 1. device of on-line real-time measuremen epitaxial wafer temperature, it is characterised in that：Described device includes black body radiation value computing Module and temperature computing module；
    The black body radiation value computing module according toObtain Pb(λ, T),
    Wherein,
    Pb(λ, T), black body radiation value,
    L (λ, T), the caloradiance of epitaxial wafer,
    R, the reflectivity of epitaxial wafer,
    ΔTT, the thermal radiant attenuation factor caused by reaction chamber window plated film,
    ΔTR, reflectivity decay factor caused by reaction chamber window plated film,
    ε(R/ΔTR), the thermal emissivity of epitaxial wafer,
    The temperature computing module according toThe temperature T of the epitaxial wafer is obtained,
    Wherein,
    Pb(λ, T), ideal black-body radiation value,
    H, Planck's constant,
    K, Boltzmann constant,
    C, the light velocity,
    λ, wavelength,
    T, temperature.
  2. 2. device according to claim 1, it is characterised in that also including thermal emissivity function selecting module, when described anti- Answer chamber window plated film for preferable opaque, smooth, even curface when, the thermal emissivity function selecting module is according to ε (R/ Δs TR)=1-R/ Δs TRObtain the ε (R/ Δs TR),
    Wherein,
    R, the reflectivity of epitaxial wafer,
    ΔTR, reflectivity decay factor caused by reaction chamber window plated film,
    ε(R/ΔTR), the thermal emissivity of epitaxial wafer.
  3. 3. device according to claim 1, it is characterised in that also including thermal emissivity function selecting module, when described anti- Answer chamber window plated film for the polishing of transparent, one side substrate when, the thermal emissivity function selecting module according to
    ε(R/ΔTR)=εcarr(1-R/ΔTR)(1-Rdiff){1+R/ΔTR*Rdiff+(1-εcarr)[(Rdiff+R/ΔTR(1-Rdiff )2)] obtain the ε (R/ Δs TR),
    Wherein,
    ε(R/ΔTR), the thermal emissivity of epitaxial wafer,
    R, the reflectivity of epitaxial wafer,
    ΔTR, reflectivity decay factor caused by reaction chamber window plated film,
    Rdiff, the scattered power of unsmooth substrate,
    εcarr, the thermal emissivity of graphite base,
    ΔTR, reflectivity decay factor caused by reaction chamber window plated film.
  4. 4. device according to claim 1, it is characterised in that also including reflectivity computing module, the reflectivity computing Module according toThe reflectivity R of the epitaxial wafer is obtained,
    Wherein,
    R, the reflectivity of epitaxial wafer,
    The light intensity ratio of m, reference light and incident light,
    IInstead, the intensity of reflected light of epitaxial wafer,
    IGinseng, the reference light intensity of epitaxial wafer.
  5. 5. device according to claim 4, it is characterised in that also including light intensity ratio computing module, the light intensity ratio Computing module according toThe light intensity ratio m of reference light and incident light is obtained,
    Wherein,
    RStandard, the reflectivity of the epitaxial wafer with standard reflectivity,
    The light intensity ratio of m, reference light and incident light,
    IInstead, the intensity of reflected light of epitaxial wafer,
    IGinseng, the reference light intensity of epitaxial wafer.
  6. 6. device according to claim 4, it is characterised in that described anti-also including reflectivity decay factor computing module Penetrate rate decay factor computing module according toObtain reflectivity decay factor Δ T caused by reaction chamber window plated filmR,
    Wherein,
    ΔTR, reflectivity decay factor caused by reaction chamber window plated film,
    R, the reflectivity of epitaxial wafer,
    R0, the ideal reflectivity of epitaxial wafer.
  7. 7. device according to claim 6, it is characterised in that also including thermal radiant attenuation factor computing module, the heat Radiation attenuation factor computing module according toObtain thermal radiant attenuation factor Δ T caused by reaction chamber window plated filmT,
    Wherein,
    ΔTT, the thermal radiant attenuation factor caused by reaction chamber window plated film,
    ΔTR, reflectivity decay factor caused by reaction chamber window plated film.
  8. 8. device according to claim 1, it is characterised in that also including data acquisition module, the data acquisition module For gathering the caloradiance L (λ, T) of epitaxial wafer.
  9. 9. the device according to claim 4 or 5, it is characterised in that also including data acquisition module, the data acquisition module Block is used for the intensity of reflected light I for gathering epitaxial waferInsteadWith the reference light intensity I of epitaxial waferGinseng。
CN201310651770.8A 2013-12-05 2013-12-05 A kind of device of on-line real-time measuremen epitaxial wafer temperature Active CN104701200B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201310651770.8A CN104701200B (en) 2013-12-05 2013-12-05 A kind of device of on-line real-time measuremen epitaxial wafer temperature

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201310651770.8A CN104701200B (en) 2013-12-05 2013-12-05 A kind of device of on-line real-time measuremen epitaxial wafer temperature

Publications (2)

Publication Number Publication Date
CN104701200A CN104701200A (en) 2015-06-10
CN104701200B true CN104701200B (en) 2018-01-16

Family

ID=53348182

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201310651770.8A Active CN104701200B (en) 2013-12-05 2013-12-05 A kind of device of on-line real-time measuremen epitaxial wafer temperature

Country Status (1)

Country Link
CN (1) CN104701200B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105092053B (en) * 2015-09-06 2017-12-22 商洛学院 Three wavelength for MOCVD epitaxy growth are excused from a college course positive infrared monitoring method and device

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007088420A (en) * 2005-08-25 2007-04-05 Sharp Corp Method of manufacturing semiconductor light emitting element
CN102455222B (en) * 2010-10-21 2013-11-13 甘志银 Method for measuring membrane temperature in metal organic chemical vapor deposition (MOCVD) equipment in real time and measuring device
CN103389170B (en) * 2012-05-07 2015-08-19 中微半导体设备(上海)有限公司 A kind of substrate temperature measuring method of vacuum treatment installation and device
CN103411684B (en) * 2013-07-17 2016-04-06 中微半导体设备(上海)有限公司 Measure the method for film temperature in reaction chamber

Also Published As

Publication number Publication date
CN104701200A (en) 2015-06-10

Similar Documents

Publication Publication Date Title
CN104697645B (en) A kind of device and method of on-line real-time measuremen epitaxial wafer temperature
US8734536B2 (en) Temperature-adjusted spectrometer
CN104697639B (en) A kind of MOCVD device real-time temperature measurement system self-calibrating device and method
CN101949852B (en) Spectral standardization-based coal quality on-line detection method
CN107611049B (en) A kind of epitaxial wafer multi-parameter in-situ monitoring method and device based on real time spectrum
US8629411B2 (en) Photoluminescence spectroscopy
WO2012109181A1 (en) Apparatus and method for temperature mapping a turbine component in a high temperature combustion environment
EP2299250B1 (en) Pyrometer adapted for detecting UV-radiation and use thereof
Lazzez et al. A Boubaker polynomials expansion scheme (BPES)-related protocol for measuring sprayed thin films thermal characteristics
Stiedl et al. Auger electron spectroscopy and UV–Vis spectroscopy in combination with multivariate curve resolution analysis to determine the Cu2O/CuO ratios in oxide layers on technical copper surfaces
CN104701200B (en) A kind of device of on-line real-time measuremen epitaxial wafer temperature
WO2019144974A1 (en) Device and method for measuring longitudinal temperature field of thin film in epitaxial growth process of nitride
CN107110709A (en) The method for calibrating the high temperature counter device of CVD or PVD reactors
Gao et al. Analysis of the optical constants of aluminum-doped zinc-oxide films by using the single-oscillator model
Schinke et al. Uncertainty of the coefficient of band-to-band absorption of crystalline silicon at near-infrared wavelengths
CN104807754A (en) Device for monitoring characteristics of wafer growth film
Witter et al. Field measurements of heat loss from skylights and lava tube systems
Jun et al. Calibration of common temperature blackbody based on thermal-infrared standard radiometer
CN104697643B (en) A kind of method of on-line real-time measuremen epitaxial wafer temperature
CN105675138B (en) Device and method for visual measurement of infrared transmission optical material mechanical processing temperature field
CN104697637B (en) A kind of real time temperature measurement method of film growth
Riech et al. Evaluation of thin films intermixing by photoacoustic spectroscopy
CN104697638B (en) A kind of MOCVD device real-time temperature measurement system method for self-calibrating
CN104807495B (en) A kind of device of monitoring wafer growing film characteristic and application thereof
CN104697666A (en) MOCVD reaction chamber temperature measurement method

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
CB02 Change of applicant information

Address after: 102206 Beijing City, Changping District Changping Road No. 97 Xinyuan Science Park B building room 503

Applicant after: BEI OPTICS TECHNOLOGY Co.,Ltd.

Address before: 100191, Beijing, Zhichun Road, Haidian District No. 27 quantum core 402 room

Applicant before: BEI OPTICS TECHNOLOGY Co.,Ltd.

CB03 Change of inventor or designer information

Inventor after: Ma Tiezhong

Inventor after: Yan Dong

Inventor after: Wang Linzi

Inventor after: Liu Jianpeng

Inventor before: Li Chengmin

Inventor before: Yan Dong

Inventor before: Wang Linzi

Inventor before: Liu Jianpeng

Inventor before: Ye Longmao

COR Change of bibliographic data
GR01 Patent grant
GR01 Patent grant
TR01 Transfer of patent right

Effective date of registration: 20200409

Address after: 330096 floor 1, workshop 8, Zhongxing science and Technology Park, No. 688, aixihu North Road, Nanchang high tech Industrial Development Zone, Nanchang City, Jiangxi Province

Patentee after: Nanchang angkun Semiconductor Equipment Co.,Ltd.

Address before: 503, room 102206, B, Xinyuan Science Park, 97 Changping Road, Beijing, Changping District

Patentee before: BEI OPTICS TECHNOLOGY Co.,Ltd.

TR01 Transfer of patent right
TR01 Transfer of patent right

Effective date of registration: 20230629

Address after: B701, Building 8, No. 97, Changping Road, Shahe Town, Changping District, Beijing 102200 (Changping Demonstration Park)

Patentee after: Beijing Airui Haotai Information Technology Co.,Ltd.

Address before: 330096 1st floor, No.8 workshop, Zhongxing Science Park, no.688 aixihu North Road, Nanchang hi tech Industrial Development Zone, Nanchang City, Jiangxi Province

Patentee before: Nanchang angkun Semiconductor Equipment Co.,Ltd.

TR01 Transfer of patent right