WO1997014047A1 - Detection electro-optique sans contact des phototensions - Google Patents

Detection electro-optique sans contact des phototensions Download PDF

Info

Publication number
WO1997014047A1
WO1997014047A1 PCT/US1996/015163 US9615163W WO9714047A1 WO 1997014047 A1 WO1997014047 A1 WO 1997014047A1 US 9615163 W US9615163 W US 9615163W WO 9714047 A1 WO9714047 A1 WO 9714047A1
Authority
WO
WIPO (PCT)
Prior art keywords
electro
optic
semiconductor structure
detector
recited
Prior art date
Application number
PCT/US1996/015163
Other languages
English (en)
Inventor
Stephen J. Fonash
Original Assignee
The Penn State Research Foundation
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 The Penn State Research Foundation filed Critical The Penn State Research Foundation
Priority to AU71155/96A priority Critical patent/AU7115596A/en
Publication of WO1997014047A1 publication Critical patent/WO1997014047A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/28—Testing of electronic circuits, e.g. by signal tracer
    • G01R31/302—Contactless testing
    • G01R31/308—Contactless testing using non-ionising electromagnetic radiation, e.g. optical radiation
    • G01R31/311—Contactless testing using non-ionising electromagnetic radiation, e.g. optical radiation of integrated circuits

Definitions

  • This invention relates to electro-optic detection of photo-voltages induced in a semiconductor structure and, more particularly, to photovoltages created in the semiconductor structure by a second probe optical beam, thus avoiding need for contact to the semiconductor structure.
  • test devices are preferably compatible with production lines and should use a contactless approach to monitoring so that the semiconductor structures are not damaged during the test procedure and can be returned to the production line after conclusion of the testing.
  • photovoltage response results from a migration of charge to a surface of the semiconductor, with a resultant electric field state created thereby.
  • the strength of the photovoltage response depends on the status of the semiconductor surface, the near surface, the bulk semiconductor, and can further depend upon the probe beam's intensity and wavelength.
  • a prior art capacitive photovoltage probe is illustrated.
  • Such capacitive probes comprise an arrangement of a cylinder 10, through which an optical beam 12 is directed.
  • a lens 14 concentrates optical beam 12 through an aperture and lens 16 where it impinges on a surface 18 of a semiconductor wafer 20.
  • Lens 16 includes a transparent conductive coating.
  • a chuck 22 supports semiconductor wafer 20 and provides a back contact thereto.
  • Optical beam 12 induces a photovoltage at surface 18, and the electric field resulting therefrom alters the capacitive coupling between surface 18 and lens 16. That change in electric field at lens 16 is sensed by an amplifier 24, whose output is fed to a processor (not shown) for analysis.
  • the capacitive probe (or chuck 22) of Fig. 1 must be rastered to enable a mapping of the capacitive changes resulting from the surface features thereof.
  • the induced photovoltage is only measured at the position of the capacitive probe.
  • light beam 12 must always be chopped so as to enable capacitive detection.
  • Fig. 1 can be found in "NON-CONTACT MAPPING OF HEAVY METAL CONTAMINATION FOR SILICON IC FABRICATION", Lagowski et al. , Semiconductor Science Technology, Vol. 7, 1992, pages A185- A192 and in U. S. Patent 5,177,351.
  • the Photon Dynamics Corporation 1504 McCarthy Boulevard., Milpitas, California markets a semiconductor test system which also senses electric field changes in semiconductor structures. In the Photon Dynamics structure, however, conductive patterns must be present on the semiconductor surface to allow voltages to be externally applied at varying points on the semiconductor surface (from controlled power sources) .
  • the Photon Dynamics system does not make use of photovoltages.
  • a block diagram of the Photon Dynamics test system is shown in Fig. 2 and comprises a light source 30 which is directed to the surface of an electro-optic sensor 34. Bottom layer 35 of electro-optic sensor 34 is constructed to reflect the incident beam back to an imaging system such as a charge- coupled device (CCD) camera 37.
  • CCD charge- coupled device
  • the output from CCD camera 37 is fed to an image processor 36 which, in turn, is coupled to a display 38. Flux coupling from structures on the semiconductor surface modifies the film properties of electro-optic detector 34, allowing imaging of working and non-working structures.
  • the test system of Fig. 2 has been developed to image an active matrix liquid crystal display 40 which is driven by outputs from control signal module 42.
  • a particular liquid crystal site e. g. 44
  • a localized electric field results which causes a local alteration of the electro-optic material within electro- optic sensor 34. That alteration is sensed by a change in the reflected beam which is sensed by CCD camera 37.
  • Defective pixels can be determined by comparison of the reflection signals from CCD camera 37 with predetermined threshold values.
  • the Photon Dynamics test system applies voltages externally to rows and columns of liquid crystal array 40 and determines if resultant changes in optical reflectivity caused by electric fields from addressed pixel sites are as expected.
  • the Photon Dynamics approach thereby requires active electrical contact to the semiconductor being tested.
  • An electro-optic detector senses induced photovoltages in a semiconductor structure through use of an electro- optic sensing material.
  • the sensing material is closely positioned to the surface of a semiconductor structure so as to be locally affected by electric field changes which occur as a result of induced photovoltages.
  • An interrogating optical beam is directed at the semiconductor structure so as to induce locally positioned photovoltages at a surface thereof.
  • An optical sensing beam is directed at the electro-optic sensing material and a detector senses reflections of the optical sensing beam from the electro- optic layer both in regions affected by the local photovoltage field changes and in regions not affected by the local photovoltage field changes. Characteristics of the semiconductor structure are deduced from reflection data derived from the optical sense beam.
  • Fig. 1 is a schematic showing of a prior art photovoltage test system which makes use of capacitive coupling.
  • Fig. 2 is a schematic showing of a prior art electro- optic test system wherein an electro-optic layer is used to enable the sensing of electric field changes from an actively operated liquid crystal display matrix.
  • Fig. 3 is a schematic diagram illustrating the invention hereof.
  • the invention employs an electro-optic detector similar to that shown in Fig. 2; however, it does not require the application of active control signals from a control module (e.g. 42 in Fig. 2) to a semiconductor structure under test.
  • semiconductor structure 50 is the unit under test and includes a number of surface features 52, 54, etc. which may or may not include conductive patterns.
  • Semiconductor structure 50 resides on a platen 56 which is connected to a reference potential and enables the application of a reference potential thereto.
  • An interrogating light source 58 outputs an interrogating light beam 60 which is scanned across semiconductor structure 50. At any point where light beam 60 is incident upon semiconductor structure 50, a counter-migration of electrons and holes occurs, thereby inducing a photovoltage which, in turn, creates electric field 62.
  • the characteristics and extent of electric field 62, for a given position of interrogating beam 60, are modified by surface features, 52, 54, etc., semiconductor properties and structure 50.
  • features of the signals e.g., strength of signal, lateral fall-off, etc.
  • conclusions can be drawn regarding the adherence of semiconductor structure 50 to a predetermined acceptance criteria.
  • Detector 63 Positioned immediately over semiconductor structure 50 is a detector 63 for the mapping of the strength distribution and the lateral extent of electric field 62.
  • Detector 63 is comprised of an electro-optic material 64 which is positioned between a pair layers 66 and 68.
  • Layer 66 is transparent and further includes a transparent conductive layer on which a voltage V can be applied.
  • Voltage V may be static or time-varying.
  • Electro-optic material 64 can comprise a liquid crystal material; a ferroelectric material or any other material which manifests an electric field impinging thereupon by a change in its optical property.
  • Such materials may be, for instance, LiTa0 3 , LiNb0 3 , KDP (potassium dihydrogen phosphate) , other materials whose crystal structure lacks inversion symmetry, poled polymers, etc.
  • Poled polymers exhibit lower electro-optic coefficients, but have the advantage of being spin-coatable and being poled in place to align the molecules.
  • Layer 68 is preferably a dielectric mirror which enables the reflection of a sensing beam 70.
  • Reflected sensing beam 72 is collected (for example by a prism (see Fig. 2) ) , is detected by CCD camera 37 and is thereafter processed by image processor 36.
  • the photovoltages induced by interrogating beam 60 in semiconductor structure 50 depend upon the quality of the bulk semiconductor; on the properties of the near surface region of the semiconductor,- and on the properties of any layers deposited on the surface of the semiconductor. Hence, the photovoltage can vary laterally for a given position of the interrogating beam and therefore, electric field 62 varies with lateral position of the interrogating beam, if material and structural properties vary laterally across the semiconductor structure. This lateral variation can be detected by sensing beam 70, due to the resulting lateral changes in the electro-optic properties of film 64.
  • Interrogating beam 60 may be of varying intensity; varying wavelength and may be chopped or pulsed. It is preferred that interrogating beam 60 impinge on semiconductor structure 50 from the back as shown in Fig. 3.
  • the properties of the various regions of semiconductor structure 50 and their lateral variation can be deduced, from the sensed photovoltage responses (or images can be compared to standards) .
  • the photovoltage at any lateral point on semiconductor structure is dictated by environment at and around the lateral point and the position of interrogating beam 60.
  • the resultant electric field 62 causes a change in the optical properties of electro-optic material 64 directly above the semiconductor surface. This changes causes a modulation of sense beam 70, with the result that reflection beam 72 is altered, accordingly.
  • various lens arrangements may be used to tightly focus sense beam 70 onto electro-optic layer 64 so as to be able to precisely image very small regions thereof which are affected by electric field 62.
  • the scanning of interrogating beam 60 and sense beam 70 may be identical so that they are directly in line with each other or, by contrast, they may be offset so as to enable sense beam 70 to determine the peripheral effects of electric field 62, which result from an offset interrogating beam 60.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Health & Medical Sciences (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Electromagnetism (AREA)
  • Toxicology (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Tests Of Electronic Circuits (AREA)

Abstract

Un détecteur électro-optique (63) capte les phototensions induites dans une structure de semi-conducteur (50) à l'aide d'un matériau de détection électro-optique (64). Le matériau de détection (64) est placé près de la surface d'une structure de semi-conducteur (50) de manière à être affecté localement par les modifications du champ électrique (62) qui se produisent du fait de phototensions induites. Un faisceau optique interrogateur (60) est dirigé sur la structure de semi-conducteur (50) de manière à induire des phototensions positionnées localement à la surface de ladite structure de semi-conducteur. Un faisceau de détection optique (70) est dirigé sur le matériau de détection électro-optique (64) et un détecteur (63) capte le faisceau de détection optique (70) réfléchi par la couche électro-optique aussi bien dans les zones affectées par les modifications locales du champ de phototension que dans les zones non affectées par lesdites modifications. Les caractéristiques de la structure de semi-conducteur (50) sont déduites des données relatives au faisceau réfléchi dérivées du faisceau de détection optique (70).
PCT/US1996/015163 1995-09-25 1996-09-23 Detection electro-optique sans contact des phototensions WO1997014047A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU71155/96A AU7115596A (en) 1995-09-25 1996-09-23 Non-contact electro-optic detection of photovoltages

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US424495P 1995-09-25 1995-09-25
US60/004,244 1995-09-25

Publications (1)

Publication Number Publication Date
WO1997014047A1 true WO1997014047A1 (fr) 1997-04-17

Family

ID=21709844

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1996/015163 WO1997014047A1 (fr) 1995-09-25 1996-09-23 Detection electro-optique sans contact des phototensions

Country Status (2)

Country Link
AU (1) AU7115596A (fr)
WO (1) WO1997014047A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9998072B2 (en) 2012-06-12 2018-06-12 Dow Global Technologies Llc Apparatus and method for locating a discontinuity in a solar array

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4859939A (en) * 1987-12-21 1989-08-22 The United States Of America As Represented By The Secretary Of The Army Non-destructive testing of SOS wafers using surface photovoltage measurements
US4891584A (en) * 1988-03-21 1990-01-02 Semitest, Inc. Apparatus for making surface photovoltage measurements of a semiconductor

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4859939A (en) * 1987-12-21 1989-08-22 The United States Of America As Represented By The Secretary Of The Army Non-destructive testing of SOS wafers using surface photovoltage measurements
US4891584A (en) * 1988-03-21 1990-01-02 Semitest, Inc. Apparatus for making surface photovoltage measurements of a semiconductor

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9998072B2 (en) 2012-06-12 2018-06-12 Dow Global Technologies Llc Apparatus and method for locating a discontinuity in a solar array

Also Published As

Publication number Publication date
AU7115596A (en) 1997-04-30

Similar Documents

Publication Publication Date Title
US5235272A (en) Method and apparatus for automatically inspecting and repairing an active matrix LCD panel
US5175504A (en) Method and apparatus for automatically inspecting and repairing a simple matrix circuit panel
US4983911A (en) Voltage imaging system using electro-optics
US5124635A (en) Voltage imaging system using electro-optics
US6407560B1 (en) Thermally-induced voltage alteration for analysis of microelectromechanical devices
US5459409A (en) Testing device for liquid crystal display base plate
JP2008537152A (ja) フラットパネル表示装置用直接検出センサー
JPH06213975A (ja) 試験中のパネルの表面上の多数の位置における電圧を観察する装置および方法
US5750981A (en) Non-contact electro-optic detection of photovoltages created in a semiconductor by a probe beam
EP0392830B1 (fr) Procédé et appareil pour la détection d'une tension
US7084649B2 (en) Method and apparatus for measuring three-dimensional distribution of electric field
KR100826505B1 (ko) 회로패턴 검출장치 및 회로패턴 검사방법
WO1997014047A1 (fr) Detection electro-optique sans contact des phototensions
Kido et al. Optical charge-sensing method for testing and characterizing thin-film transistor arrays
US5614839A (en) Method for optically testing flat panel display base plates
JPH0580083A (ja) 集積回路の試験方法および装置
US7450237B2 (en) Non-invasive electric-filed-detection device and method
US6894514B2 (en) Circuit pattern detecting apparatus and circuit pattern inspecting method
US7710573B2 (en) Device and method for the non-invasive detection and measurement of the properties of a medium
Jeong et al. Dynamic characteristics of the PDLC-based electro-optic modulator for TFT LCD inspection
JP5333150B2 (ja) 静電解析方法及び静電解析装置
JPH03167490A (ja) 実装プリント板試験装置
JPH0587839A (ja) 電圧分布測定方法
JP2005172730A (ja) 回路基板の断線検査装置
JP2596865B2 (ja) 回路試験用電界センサー

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AU CA JP KR

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: CA