WO1995018369A1 - Dispositif de detection d'un defaut de cablage dans un substrat de cablage - Google Patents
Dispositif de detection d'un defaut de cablage dans un substrat de cablage Download PDFInfo
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- WO1995018369A1 WO1995018369A1 PCT/JP1994/002189 JP9402189W WO9518369A1 WO 1995018369 A1 WO1995018369 A1 WO 1995018369A1 JP 9402189 W JP9402189 W JP 9402189W WO 9518369 A1 WO9518369 A1 WO 9518369A1
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- Prior art keywords
- wiring
- detection device
- optical sensor
- voltage
- wiring board
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
- G01N21/956—Inspecting patterns on the surface of objects
-
- 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
- G01R31/309—Contactless testing using non-ionising electromagnetic radiation, e.g. optical radiation of printed or hybrid circuits or circuit substrates
Definitions
- the present invention relates to a detection device for detecting a wiring defect on a wiring board.
- a 3 mm pitch wiring width is required, and a 0.1 mm pitch wiring width is required for COB (chip-on-board) substrates.
- COB chip-on-board
- Such densification of the printed wiring board causes an increase in the occurrence of defects such as disconnection and short circuit of the wiring. Therefore, a more accurate and low-cost wiring inspection method is required in the inspection process of the printed wiring board.
- the occurrence of defects such as disconnection or short circuit of wiring increases as the number of wirings increases, as the wiring width decreases, and as the number of layers increases. Therefore, inspection of continuity and insulation of printed wiring boards, and inspection of thinning and thickening of wiring, etc., are indispensable steps in order to prevent trouble after mounting electronic components.
- contact type inspection machines can be roughly classified into two types: contact type and non-contact type.
- contact type inspection machines There are two types of contact type inspection machines: a system that uses a fixture that is compatible with a printed wiring board, and a flying type that performs electrical inspection by freely moving several probe pins on the printed wiring board.
- pressure is applied to the contact probe pins with springs to bring them into contact with the lands on the printed wiring board, and a certain bias voltage is applied to detect the state of conduction between each land, that is, each probe pin, and to use the reference data or Inspect the wiring by comparing it with the design data. Since the fixture is required to be manufactured for each printed wiring board to be inspected, the design and manufacture of the fixture are costly and lack the flexibility.
- a non-contact type inspection machine there is a printed wiring board appearance inspection machine which performs an inspection using an image of a printed wiring board.
- the printed wiring board appearance inspection system compares the image of the inspected object with the image of a non-defective sample, and a feature extraction method that checks whether a pattern has been formed in accordance with preset design rules.
- inspection methods based on comparison with CAD data of printed wiring boards singularity recognition methods, and methods based on a combination of them. These methods can detect narrow wiring points. However, it cannot detect the location of the short circuit in the wiring.
- a voltage detector using an electron beam which is one of the non-contact type inspection devices, detects a voltage between wirings or between a wiring and a probe, and inspects a printed wiring board based on the detected voltage.
- This voltage detector can detect the voltage without bringing the probe into contact with the substrate to be inspected.
- this voltage detector requires that the part to be measured be placed in a vacuum and that part must be exposed. In addition, the part to be measured by the electron beam may be damaged.
- JP-A-59-500-186 and JP-A-63-133680 disclose electro-optic crystals.
- An inspection device for an integrated circuit using the same is described. This inspection device makes use of the property that the birefringence of electro-optic material changes depending on the electric field.
- electro-optic materials For electro-optic materials
- Electro-optical crystal used here is an inorganic substance such as L i N b 0 3.
- Japanese Patent Application Laid-Open No. 3-15639 / 1991 discloses that an organic substance such as ethyl alcohol, ethylene glycol, or the like, is used for the electro-optic It has been proposed to put it between the materials, but it has the disadvantage that the operation is complicated in practice. Further, since the wavelengths at which these inorganic electro-optical materials can transmit light are in the near-infrared region, there is a disadvantage that the light source used for detection is limited.
- Japanese Patent Application Laid-Open No. 11-197878 discloses a pudding with a plurality of electronic components: 'A non-contact type inspection machine for testing wiring boards using a polymer electro-optic material. Has been described. However, while this tester can measure signals flowing between electronic components, it cannot detect defects such as thinned or short-circuited wiring on printed wiring boards.
- liquid crystal display panels are expected to have higher image quality due to their larger size and finer pitch, and research is currently being actively conducted on their practical use. Has been commercialized.
- an active matrix type liquid crystal display panel it is necessary to form an active element such as a transistor diode as a switching element in all pixels of the liquid crystal display panel.
- an active matrix type liquid crystal display panel having more than one million pixels have become commercially available.
- a pad for external connection of a thin-film transistor (TFT) array of an active matrix type liquid crystal display panel or a pad for measurement is used to measure the resistance between each gate line, drain line, and CS bus.
- TFT thin-film transistor
- a device that inspects only for disconnections and short circuits is equivalent to this.
- an electrical measurement cannot test every pixel of an active matrix liquid crystal display panel having more than one million pixels. Even if a 100% inspection is performed, it takes too much inspection time, which is not practical.
- As an optical inspection there is a visual perception inspection of a liquid crystal display panel performed after injecting liquid crystal between a pixel electrode and a counter electrode of an active matrix type liquid crystal display panel to form a cell.
- the surface of the LCD panel to be measured is irradiated with light, an image is read by a two-dimensional CCD sensor instead of human eyes, and adjacent periodic patterns are sequentially compared using pattern recognition and image processing technology. Then, the difference is detected as a defect. Since this inspection is basically a visual inspection, it can recognize not only dust and foreign matter adhering to the channel, but also pattern defects, but cannot accurately detect electrical disconnection and short circuit.
- the non-contact type inspection machines there is a voltage detector using an electron beam, and there is also a system that measures the secondary electron energy by a charged semiconductor.
- This voltage detector can detect the voltage without bringing the probe into contact with the panel to be measured.
- the liquid crystal display panel to be measured must be placed in a vacuum and the part to be inspected must be exposed. Also, the liquid crystal display panel to be measured by the electron beam may be damaged.
- JP-A-5-240800 and JP-A-5-256794 describe electro-optical materials.
- an inspection apparatus for a liquid crystal display substrate using a polymer-dispersed liquid crystal sheet is described.
- the inspection device using the above-described electro-optic material utilizes the property that the birefringence of the electro-optic material changes depending on the electric field from the liquid crystal display substrate.
- an electro-optic material is irradiated with a laser beam, the phase difference between the vibration components in two directions orthogonal to each other, that is, the polarization state, changes according to the magnitude of the electric field.
- this change in the polarization state can be converted into a change in electrical intensity by passing the polarized light through a polarizing plate set in a certain appropriate axial direction. By observing the strength at a position where the electric strength is high, it is possible to inspect the defect of the liquid crystal display substrate.
- the electro-optical material is now generally inorganic crystals such as L i N b 0 3 is the mainstream. Since the dielectric constant of these inorganic crystals is generally higher than the dielectric constant between the portion to be measured and the inorganic crystal, there is a disadvantage that the electric field applied to the inorganic crystal becomes small and the measurement sensitivity is reduced. In addition, in general, crystals have the disadvantage that large areas cannot be obtained, whether inorganic or organic.
- the polymer-dispersed liquid crystal sheet is enclosed in a transparent case and placed above the liquid crystal display panel.
- the response speed of the inspection device depends on the response speed of the liquid crystal molecules to the electric field, so that the response time is on the order of milliseconds, and the inspection time is limited.
- multi-terminal integrated circuits such as LSI require a conversion connector to expand the terminal pitch when mounting on a printed circuit board or the like.
- clock integrated circuits since recent high-speed clock integrated circuits generate a considerable amount of heat, they are often packaged in ceramic packages with good heat dissipation, and integrated circuits that do not require much heat dissipation are packaged in inexpensive plastic packages. .
- Fine-pitch packages for these integrated circuits are in the process of being developed. At present, packages with a pitch of 0.1 mm are being considered, while those with a pitch of 0.3 mm are being considered.
- the probe is formed in a thin needle shape so that it can be used for a narrow electrode, and the surface of the probe is plated with gold. This has the disadvantage that the gold plating of the electrode is damaged during inspection.
- Inspection methods based on mechanical contact as described above have limitations, and it is difficult to create fixtures and pin probes for packages with a pitch of less than 0.1 mm and to measure using them.
- the present invention can cope with a narrow wiring width, and can detect a thinning of a wiring, a conduction state of the wiring, and a short-circuit position of the wiring in a non-contact manner. It is a first object of the present invention to provide a detection device for detecting a wiring defect.
- a second object of the present invention is to provide a detection device for detecting a defect in a wiring board of a printed wiring board.
- a third object of the present invention is to provide a detection device for detecting a defect of a wiring of a printed wiring board, which can detect a defect of a wiring of an inner layer as well as a wiring of a front surface and a rear surface of the multilayer substrate in a non-contact manner.
- a fourth object of the present invention is to provide high detection accuracy and to be able to cope with a small pixel area.
- An object of the present invention is to provide a detection device that performs non-contact detection without damaging the surface.
- a fifth object of the present invention is to provide a device for finding a defect in wiring, which can cope with fine pitch of an integrated circuit package. Disclosure of the invention
- a detection device for detecting a defect in a wiring of a wiring board including at least one wiring comprises:
- a light source an optical unit that causes light from the light source to enter the optical sensor; and a signal corresponding to the intensity of the reflected light when a voltage is applied to the wiring by detecting reflected light from the optical sensor.
- a processing unit that processes the signal derived from the detection unit and outputs a signal corresponding to the presence or absence of a defect in the wiring;
- the defect of the wiring is thinning or disconnection of the wiring, a short circuit between the wirings, or any combination thereof.
- the detection device configured as described above detects a wiring defect using the electro-optic effect.
- a known technique using the electro-optic effect for example, a detection device as disclosed in Japanese Patent Application Laid-Open No. H11-197778 aims to measure signals between electronic components mounted on a printed wiring board.
- the detection device of the present invention aims to detect a wiring defect before electronic components are mounted. Further, the detecting means moves on the substrate to be inspected and scans, thereby detecting a wiring defect.
- the detection device of the present invention is different from the device disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 1119778, in which only a light beam is scanned by a mirror.
- the optical sensor and the sensor head may be integrated or may be separate.
- the optical sensor is fixed on the wiring board in advance so as not to contact the wiring board, and the wiring board is scanned by moving the sensor head over the fixed optical sensor.
- the optical sensor may be formed to have substantially the same size as or larger than the wiring board to be inspected. By doing this, the optical sensor is fixed and By moving the head to the sensor, the wiring board can be scanned with beam-like light from the head.
- the measurement time can be shortened by making the optical means and the detection means linear and using linear light instead of beam light. Also, the measurement time can be shortened by making the optical means and the detection means planar and using planar light instead of beam light.
- the detection device of the present invention can also be used to detect a wiring defect in a printed wiring board having at least one layer of wiring.
- the printed wiring board may be a printed wiring board having one layer of wiring or a multilayer printed wiring board.
- detecting wiring defects in a multilayer printed wiring board it is possible to detect wiring defects in all layers with a single operation, or to detect wiring defects for each layer c
- the material of the printed wiring board is not particularly limited, and any material commonly used as a printed wiring board can be measured by the detection device of the present invention.
- the detection device of the present invention can also be used for inspection of a liquid crystal display panel including a transparent glass substrate having a transparent electrode.
- a liquid crystal display panel includes a simple matrix type liquid crystal display panel typified by STN, an active element (a transistor such as a thin film transistor or a bulk transistor, and a metal, insulator, or metal diode).
- an active matrix type liquid crystal display panel having a varistor or a metal / semi-insulator diode (a diode such as a ring diode).
- disconnection, thinning, and short-circuiting which are defects of both transparent electrodes are simultaneously performed. Can be detected.
- the transparent electrode means a scanning electrode in a simple matrix type liquid crystal display panel, and means a scanning electrode, a signal electrode and an active element in an active matrix type liquid crystal display panel.
- the detection device of the present invention can detect a wiring defect.
- the detection device of the present invention can also be used to detect a defect in a package for an integrated circuit.
- packages include cer am ic—B all G rid A rray (c—BGA) and plastic B all G rid A rr ay (p—GBA), Quad Flat Package with Bum per (BQFP), Butt Joint Pin in Gr id Ar r ay (BJ PGA), Ce rdip, Ce r qu ad, Ce ramic L eaded Ch ip Carrier (CLCC) .P lastic Lead d Ch ip Carrier (PLCC).
- Dua l Flat Pa ckage (DFP), cer amic— Dua l I n — line Pa ckage (c one DIP) , Plastic—Dual l In—line Package (p-DIP), Small 0 ut-1 ine Pa ckage (SOP) .Dua 1 Tae Carrier Pa ckage (DTCP) ⁇ Quad F 1 at Pa ckage (QFP).
- Fine pit ch Quad F 1 at Pa ckage (FQFP) Quad F lat Pa ck agewi th Gua rdri ng (GQFP), cer ami c P in Gr id Ar r ay (c— PGA) , Plastic P in Gr id Ar r ay (p— PGA),; Lead 1 ess Ch ip Carrrier (LCC).
- L and Gr id Ar r ay (LGA) Low profi 1 Quad Flat Lackage (LQFP) L-QUAD, Mu lti—Chip Module (MCM), Metric Quad Flat Rack (MQFP), cer amic Quad Flat Rack Age (c—QFP).
- Quad F lat High Package QFH
- Quad F lat I-leade d Package QFI
- Quad F lat J-le aded Pac kage QFJ
- Quad F lat non—leaded Pa cka ge QFN
- Tae Carrier Package TCP
- Quad Tae Carrier Package QTC P
- Quad In-line Package QU IP
- Shrink Du Al In — Line P ac kage SD IP
- S i ng le I n— line Pac kage SI
- the optical sensor is disposed in a non-contact and close proximity so as to cover the entire part of the package for the integrated circuit bonded to the integrated circuit, and a voltage is applied to the electrodes from the pin side, and the principle described above is applied. Thus, the defect of the electrode of the package for the integrated circuit is detected.
- the detection device of the present invention can also be used to inspect the package after the solder resist has been applied.
- FIG. 1 are views sequentially showing the manufacturing process of the optical sensor 1 of the detection device according to the present invention.
- FIG. 2 is a diagram for explaining how to measure the electro-optic constant of the optical sensor 1 of FIG.
- FIG. 3 is a diagram schematically showing a configuration of an embodiment of the detection device according to the present invention.
- FIG. 4 is a diagram showing a configuration of a modified example of the detection device according to the present invention.
- FIG. 5 is a diagram showing a configuration of another embodiment of the detection device according to the present invention, in which the optical sensor and the sensor head of FIG. 3 are integrated.
- FIG. 6 is a diagram showing an arrangement when the detection device of the present invention is applied to detection of a defect on a printed wiring board.
- FIG. 7 is a diagram showing an arrangement when the detection device of the present invention is applied to defect detection of a simple matrix type liquid crystal display panel.
- FIG. 8 is a diagram showing an arrangement when the detection device of the present invention is applied to defect detection of an integrated circuit package.
- FIG. 9 is a diagram showing an arrangement when the detection device according to the present invention is applied to detection of thinning of a wiring of a printed wiring board.
- FIG. 10 is a diagram showing an image obtained for the wiring of the printed wiring board of FIG.
- FIG. 11 is a diagram showing an arrangement when the detection device according to the present invention is applied to detection of thinning of wiring of a simple matrix type liquid crystal display panel.
- FIG. 12 is a diagram showing an image obtained from a simple matrix type liquid crystal display panel by the arrangement of FIG.
- FIG. 13 is a diagram showing a wiring pattern used for measurement for detecting a short circuit of a wiring by the detecting device according to the present invention.
- FIG. 14 is a diagram showing an image of a simulated liquid crystal display panel used for measurement for detecting a short circuit between the electrodes of the TFT of the TFT-active matrix type liquid crystal display panel by the detection device according to the present invention. .
- FIG. 15 shows that the detection device according to the present invention uses a TFT-active matrix type liquid.
- FIG. 3 is a diagram showing an image of a simulated liquid crystal display panel used for measurement for detecting a disconnection between electrodes of a TFT of a liquid crystal display panel.
- FIG. 16 is a diagram showing an arrangement when the detection device according to the present invention is applied to detection of disconnection of an integrated circuit package.
- FIG. 17 is a diagram showing a pattern obtained from the detection device in the arrangement of FIG.
- FIG. 18 is a diagram showing an arrangement when the detection device according to the present invention is applied to detection of a short circuit in a package for an integrated circuit.
- FIG. 19 is a diagram showing a pattern obtained from the detection device in the arrangement of FIG.
- FIG. 1 (a) shows steps of manufacturing an optical sensor used in the detection device according to the present invention.
- a transparent electrode 12 is provided on a transparent substrate 10 (FIG. 1 (a)).
- the transparent substrate 10 needs to be transparent in the wavelength range of the incident light.
- glasses such as soda glass, quartz glass or Pyrex glass and optical plastics are suitable.
- incident light is obliquely incident on a thin film of a polymer nonlinear optical material, and a 33 which is a maximum nonlinear effective component of the material is determined. It is desirable to use it.
- the thickness of the transparent substrate 10 is desirably about 100 m or less. More preferably, the thickness is about 300-400 / m in consideration of handleability.
- the transparent electrode 12 needs to be transparent in the wavelength range of the incident light.
- the transparent electrode 1 ITO (indium Thi down-Okisai de) and can be used inorganic conductors, such as S n 0 2.
- the thickness of the transparent electrode 12 is preferably small. It is preferable that the film thickness of the transparent electrode 12 is about 100-1000.
- the method is not particularly limited, and any conventionally known method can be used. For example, a vacuum deposition method can be used. Alternatively, commercially available Nesa glass (registered trademark) or the like may be used.
- a thin film 14 of a polymer nonlinear optical material is provided on the transparent electrode 12 (FIG. 1 (b)).
- any conventionally known thin film forming method can be used.
- high molecular nonlinear optical material is dissolved in a solvent such as cyclohexanone, the solution transparent electrode 1 2 on about 2 0 0 - c then spin coated at a rotational speed of 5 0 0 0 rpm, heated The solvent is removed by evaporation to produce a thin film 14 of a polymer nonlinear optical material.
- the thickness of the thin film 14 must be such that the electric field generated from the wiring of the wiring board can be sufficiently taken in.
- the dielectric constant between the optical sensor and the wiring is determined by the polymer nonlinearity.
- the dielectric constant is smaller than the dielectric constant of the optical material, it is preferably about 100 to 100 m, which is sufficiently thicker than the distance between the optical sensor and the wiring of the printed wiring board. More preferably, the thickness is about 20 ⁇ m.
- the atomic group having nonlinear optical activity (also referred to as chromophore) in the polymer nonlinear optical material be oriented in a certain direction in the thin film 14. This is because a large nonlinear optical effect can be obtained by the orientation of the atomic groups.
- the direction of the orientation may be a direction parallel to the plane of the thin film 14 or a direction perpendicular to the plane of the thin film 14. Alternatively, it may be inclined with respect to the surface of the thin film 14.
- the alignment treatment for example, the following method is used.
- an alignment electrode 16 for alignment processing is provided on the thin film 14.
- the alignment electrode 16 may be provided on the entire surface of the thin film 14, or may be provided only on a portion to be subjected to alignment treatment.
- the material of the alignment electrode 16 preferably has a small resistance value, and for example, gold, silver, copper or aluminum can be used.
- the thickness of the alignment electrode 16 is preferably about 60 O A or more, particularly about 100 to 1
- 500 A is desirable.
- a vacuum evaporation method can be used.
- an electrically conductive adhesive is used. Can be used.
- the thin film 14 is heated to a temperature equal to or higher than its glass transition temperature using a hot plate 18.
- the heating temperature is lower than the melting point at which the thin film 14 can maintain its shape.
- a voltage is applied between the orientation electrode 16 and the transparent electrode 12 on the thin film 14.
- the applied voltage is preferably as high as possible, and the application time is a time sufficient for completing the orientation of the atomic group under the applied voltage.
- the applied voltage is preferably about 100 to 30 OV / ⁇ m within a range where the thin film 14 does not cause dielectric breakdown, and the application time is preferably about several minutes.
- the thin film 14 is cooled to room temperature while the voltage is applied to the thin film 14, and the orientation of the atomic groups is fixed.
- the atomic groups can be oriented in a direction perpendicular or oblique to the surface of the thin film 14.
- the alignment electrode on the thin film used for the alignment treatment is generally removed by an etching agent after being used as an electrode for measuring the electro-optical constant of the thin film and a reflective film described later.
- a reflection film is provided on the thin film from which the alignment electrode has been removed by an etching agent.
- a metal mirror or a dielectric multilayer mirror can be used as the reflection film.
- the multilayer mirror of the dielectric can be used such as a laminate of a a thin film of S i 0 2 thin film and T i 0 2 alternately.
- a vacuum evaporation method can be used for the lamination.
- the optical sensor thus obtained is diced according to the shape of the wiring board.
- the polymer nonlinear optical material used in the optical sensor of the present invention an inorganic material and an organic low-molecular material are known in addition to the polymer material, but the inorganic material and the organic low-molecular material have high sensitivity and large size. In view of the difficulty in obtaining the above film, it is preferable to use a polymer nonlinear optical material in the present invention.
- polymer nonlinear optical material used in the present invention it is preferable to use a polymer material having a second-order nonlinear optical effect, a small dielectric constant, a high electrooptic constant, and high transparency.
- P is the main chain of the nonlinear optically active copolymer.
- P is preferably a polyvinyl type, a polysiloxane type, a polyoxyalkylene type, a polyvinylidene type, a polyurethane type, a polytriazine type, a polyester type or a polyamide type.
- S is a direct bond or a spacer group consisting of a straight chain hydrocarbon group having 1 to 20 carbon atoms. Since the spacer group is highly flexible, the mobility of the chromophore attached to the end of the spacer group is increased.
- [X-YZ] is a chromophore having nonlinear optical activity.
- X is an electron donating group, and is preferably, for example, 1NRt—, 10— or 1S—.
- hydrogen or a lower alkyl group such as a methyl group can be used.
- Y is a 7-electron shared system, for example, a stilbene system, an azobenzene system, a biphenyl system, a diphenyl butadiene system, or a dicyanovinyl-hexatriene system is preferable.
- Z is an electron-withdrawing group, for example, preferably —NO 2 , CN or CF 3 .
- A is a copolymer unit having no nonlinear optical activity
- B is a copolymer unit having another function and / or a functional copolymer unit.
- the chemical bond between the spacer group and the chromophore includes, for example, One S—X—Y—z, One S—Y—Z, —S— ⁇ - ⁇ —X
- [X- ⁇ - ⁇ ⁇ ⁇ ] which is a chromophore having nonlinear optical activity, constitutes a main chain unit of the nonlinear optically active copolymer.
- the definitions of X, ⁇ , ⁇ , ⁇ and ⁇ are the same as in the case of the above general formula I.
- the chemical bonding aspects of chromophore include, for example,
- polymer nonlinear optical material examples include, for example, US Pat. Nos. 4,801,670, 5,415,510, 5,155,195, and 5,171,803. Nos. 4,694,066, 4,795,644, 4,822,865, 4,810,338, 4,835,235, 4 No. 4, 851, 502, No. 4, 865, 430, No. 4, 867, 540, No. 4, 913, 844, No. 4, 915, 491, No. 4, 962, 160 Nos. 4,757,130, 4,808,332, 4,978,476, 5,002,361, 5,041,509, 5 , 044, 725 and 5,061.760 can be used.
- a methacrylate copolymer in which nitroaminostilbene or indolinylazobenzene shown in the following formulas m and IV is pendant can be used as the polymer nonlinear optical material.
- a polymer containing a triazine ring which contains a repeating unit represented by the following formula V, is also preferable as the polymer nonlinear material.
- a polymer containing a triazine ring which contains a repeating unit represented by the following formula V, is also preferable as the polymer nonlinear material.
- a high-quality film can be formed, and a material with better heat resistance can be expected (
- X 1 and X 2 may be the same or different and are S, NR 1 or 0; R 1 is a hydrogen atom, an alkyl group or an aryl group;
- Y is an alkylene group, a divalent substituted or unsubstituted aromatic ring group containing no dye molecule residue, a bond or a condensed aromatic ring group, or
- a r 1 and A r 2 are divalent substituted or unsubstituted aromatic groups which may be the same or different,
- R 2 and R 3 are a hydrogen atom or an alkyl group which may be the same or different,
- Q is a carbon atom or a gay atom
- n 1 to 4
- Z is a spacer group consisting of a group represented by one G— (CH 2 ) n— (n is an integer of 1 to 10) or is a direct bond;
- G is S, NR 4 or 0,
- R 4 is a hydrogen atom, an alkyl group or an aryl group
- A is an organic dye molecule residue in which an electron-donating group and an electron-withdrawing group are conjugated via a 7-electron system.
- the weight average molecular weight of the polymer is generally from about 5,000 to about 1,000,000.
- copolymers represented by the following formulas VI and VII can be used as the polymer nonlinear optical material.
- Such a polymer non-linear optical material has a smaller dielectric constant than an inorganic electro-optic crystal, and even when placed near the part to be measured, the voltage applied to the wiring can be efficiently taken into the material. Sensitivity can be improved. In addition, the response speed of these polymer nonlinear optical materials to an electric field is extremely fast, on the order of picoseconds or more, and is suitable for high-speed measurement.
- FIG. 2 shows a measuring device for determining the electro-optic constant of an optical sensor in which non-linear optically active atomic groups are oriented in a direction perpendicular to the surface of the thin film 14.
- reference numeral 10 denotes a transparent substrate
- 12 denotes a transparent electrode
- 14 denotes a thin film of a polymer nonlinear optical material
- 20 denotes a reflection film also serving as an electrode.
- the light from the light source 22 becomes linearly polarized light by the polarizer 23, enters from the transparent substrate 10 side of the optical sensor, passes through the thin film 14, and is reflected by the reflective film 20.
- the reflected light is detected by the photoelectric converter 28 through the Babinet Solei compensator 24 and the analyzer 26.
- a modulation voltage is applied between the transparent electrode 12 and the thin film 14 from an external power supply, and the birefringence of the polymer nonlinear optical material changes according to the modulation voltage.
- the light intensity also changes. For details of the measurement method, see, for example, C. Teng and HT Man, Ap. 1. Phys. Lett. 56 (18), 30A ril 1990.
- FIG. 3 is a diagram schematically showing the configuration of an embodiment of the detection device of the present invention. That is, the detection device DT of the present invention includes an optical sensor 100 having a thin film of the above-described polymer nonlinear optical material, a sensor head 102, and a signal processing unit 104, and the sensor head 102 is a light source. 30, optical means 32 for causing light from the light source 30 to enter the optical sensor 100, and detection means 34 for detecting light reflected from the reflection film of the optical sensor 100 when the light incident on the optical sensor 100 is detected. Have.
- the light source 30 commercially available semiconductor lasers capable of outputting wavelengths from 600 to 1550 nm, gas lasers such as He—Ne lasers, solid state lasers such as YAG and YV ⁇ 4, and their second harmonics Or a laser that oscillates light.
- gas lasers such as He—Ne lasers
- solid state lasers such as YAG and YV ⁇ 4
- their second harmonics Or a laser that oscillates light.
- the optical means 32 for causing the light from the light source 30 to enter the optical sensor 100 includes, for example, a polarizer 36 for selecting only a predetermined polarization component of the light from the light source 30, and an electrical device.
- the optical means 32 can be arranged linearly or planarly correspondingly.
- the optical members 40 and 42 for example, an optical lens, an optical mirror, a prism, and an optical fiber can be used.
- the detection means 34 for detecting the reflected light from the optical sensor 100 is an analyzer 44 4 angled to pass a polarization component perpendicular or parallel to the polarization component passing through the polarizer 36. And a photoelectric converter 46 such as a photodiode or a photomultiplier tube. The electric signal from the photoelectric converter 46 is processed by a signal processing unit 104 such as a computer.
- the detecting means 34 are also arranged linearly or planarly correspondingly.
- the linear detection means can be constituted by, for example, a combination of a linear analyzer and an array type photodiode.
- the optical sensor 100 is arranged with its reflective film 20 side non-contacting and close to the wiring to be measured on the wiring board.
- An AC voltage or a DC voltage is applied to the wiring.
- any frequency from 1 Hz to the terahertz band can be used, but from the ease of measurement, the frequency from 10 OHz to the gigahertz band can be used. preferable.
- the moving head moves the sensor head 102 or the wiring board, thereby scanning the wiring board with light from the optical means 32. May pick up noise. Since this vibration noise exists in the range of 1 ⁇ ⁇ to 50 kHz, the alternating current applied to the wiring is taken in the range of 50 kHz to 100 kHz, and the noise is removed by a bandpass filter. Is preferred.
- the angle of incidence ranges from about 1 degree to 57 degrees, preferably from about 20 to 45 degrees.
- the light incident on the optical sensor 100 passes through the thin film 14 of the polymer nonlinear optical material, and is reflected by the reflection film 20.
- the birefringence of the thin film 14 depends on the voltage applied to the wiring. Since it changes according to the generated electric field, the plane of polarization of light passing through the thin film 14 changes according to the change in the refractive index. As a result, the polarization planes of the incident light and the emitted light are different, so that the intensity of the light passing through the analyzer 44 changes depending on the direction of the polarization plane. This change in intensity is converted into an electric signal by the photoelectric converter 46.
- the transparent electrode 12 in the optical sensor 100 is preferably at a ground potential.
- the optical sensor 100 and the sensor head 102 may be integrated or separate. When integrated, the optical sensor 100 and the sensor head 102 are separated, and when separated, the sensor head 102 is attached to the wiring board by a plane moving means (not shown). Move on the wiring without contact. This scans the wiring board.
- a plane moving means known means can be used, and usually, the moving accuracy is ⁇ 30 m or less in repetition.
- the beam diameter can be changed by the optical member 40 to a diameter of about 1 zm-5 mm. Since the beam diameter of this light corresponds to the detection accuracy of the device, the detection device DT of the present invention has a detection accuracy of about 1 to 5 mm.
- the detection pitch of 1.27 mm required for the substrate for THD the 0.3 mm pitch required for the substrate of SMD, and
- the number required for fine-pitch liquid crystal display panels is 10 to 10 It can detect defects in transparent electrodes with a unit pitch of 0, and can be applied to integrated circuit packages with a pitch of 0.3 or 0.1 mm.
- the voltage applied to the wiring is about IV to about 1 kV. AC or DC. Defect-free wiring board to sensor
- the distribution state of the voltage detected by the detecting means 34 is determined by the image processing of the signal processing unit 104 such as a computer for each position scanned by the sensor head 102 Display means (not shown) Will be displayed. In this way, it is possible to detect the presence or absence of a wiring defect such as thinning, disconnection, short circuit between wirings, or any combination of these.
- an integrated element 48 in which the light source 30 and the photoelectric converter 46 in the sensor head 102 are integrated can be used.
- an integrated element 48 for example, there is an integrated element of a light emitting diode and a phototransistor, which is commercially available under the trade names of a photoreflector and a photosensor.
- the detection device DT of the present invention can also be used to simultaneously measure the wiring of all the layers in the multilayer printed wiring.
- the voltage measured by the detection means 34 is related to both the distance between the optical sensor 100 and the wiring and the dielectric constant between the optical sensor 100 and the wiring. That is, even when the same voltage is applied to each layer, the value of the voltage measured as the wiring is farther from the optical sensor 100 and as the dielectric constant between the optical sensor 100 and the wiring is lower is lower. Lower. Therefore, it becomes possible to identify the state of the wiring for each layer and measure it at the same time.
- the detection device DT of the present invention can be used, for example, to detect a defect of an active matrix type liquid crystal display panel using TFT as an active element.
- a voltage is applied only to the signal electrodes of the active matrix type liquid crystal display panel. If a short circuit occurs between the source and the drain of any of the TFTs, a voltage is also applied to the pixel electrode through the drain, so that a signal is observed at the pixel electrode to which the short-circuited TFT is connected.
- a voltage is applied to the scan electrode.
- the gate and the drain are short-circuited, a voltage is also applied to the pixel electrode through the drain, so that a signal is observed at the pixel electrode to which the TFT with the gate and the drain short-circuited is connected.
- the voltage when a voltage is applied between the signal electrode and the scan electrode so that the TFT is in a switch-on state, the voltage may be applied between the source and the gate or at the intersection of the signal electrode and the scan electrode.
- the normal voltage is not applied to the pixel electrode, so that a normal signal is not observed at the pixel electrode where the short circuit exists.
- a voltage is applied between the signal electrode and the scanning electrode. If the signal electrode is broken, no signal is observed on the pixel electrode since no voltage is applied to the pixel electrode beyond the broken point. Similarly, to detect a disconnection of the scanning electrode, a voltage is applied between the signal electrode and the scanning electrode. If the scanning electrode has a disconnection, no voltage is applied to the pixel electrode beyond the disconnection point, and no signal is observed on the pixel electrode.
- the detection device DT in which the optical sensor 100 and the sensor head 102 are integrated is not so contacted with the wiring in advance, and Scan the wiring by moving the sensor closely or by fixing the optical sensor 100 in advance so as not to touch the wiring and moving the sensor head 102 only. .
- the voltage application socket When detecting a short circuit in the wiring of the integrated circuit package with the detecting device DT, connect a voltage application socket to the pin side of the integrated circuit package and apply a pressure to one wiring. Therefore, the presence or absence of the wiring for detecting the voltage is checked by the detecting device DT. If a voltage is detected from a wiring other than the wiring to which the voltage is applied, it means that the wiring is short-circuited. By performing such a procedure for all wirings in order, it is possible to inspect all wirings for short circuits.
- the voltage application socket may be connected to the scanner, and the voltage may be applied to the wiring in order.
- the thickness of the transparent electrode 12 is 185 A, and the resistance value is 4502 b.
- the glass transparent substrate 10 on which the transparent electrode 12 is formed is washed in pure water, and the above solution is applied onto the transparent electrode 12 by spin coating. After drying at 160 ° C for 5 hours to remove the cyclohexanone by evaporation, a thin film 14 is formed. When the thickness of the obtained thin film 14 was measured with a stylus thickness gauge, it was 15 m.
- a gold orientation electrode 16 is provided on the thin film 14 using a normal vapor deposition apparatus.
- the thickness of the alignment electrode 16 is about 1,000, and the diameter is 5 mm.
- the lead is connected to the alignment electrode 16 and the transparent electrode 12 by the silver paste.
- the thin film 14 is heated to 140 ° C. or more, which is its glass transition temperature, using a hot plate 18. After imparting mobility to the chromophore having nonlinear optical activity by heating, a DC voltage of 150 VZm is applied between the alignment electrode 16 and the transparent electrode 2 for 5 minutes. In this way, the thin film 14 is cooled down to room temperature with the voltage applied, and the orientation of the chromophore is fixed.
- the orientation electrode 16 is removed by etching, by depositing alternately and S i 0 2 and T i 0 2 on the thin film 14, providing the reflective film 20 having a thickness of about 1.8.
- the reflectance was 80%.
- FIG. 5 shows the configuration of another embodiment of the detection device DT of the present invention.
- the optical sensor 100 and the sensor heads 1 and 2 manufactured in the steps shown in (d) to (d) are integrated.
- the sensor head 102 of this embodiment the first and the second
- the second optical members 40 and 42 are omitted, and the light source 30 emits laser light having a wavelength of 830 nm. It is a semiconductor laser that is generated.
- the beam shape of the laser beam from the light source 30 is shaped by a collimator lens 47, and the shaped laser beam is converted to linearly polarized light by a polarizer 36.
- the ⁇ 4 wavelength plate 38 is made of mica, and the photoelectric converter 46 is a photodiode.
- the beam diameter of the laser light emitted from the light source 30 is 50 am, and the angle of incidence on the optical sensor 100 is 45 degrees. Extinction ratio of the polarizer one 36 10 - 4.
- the analyzer 44 may be of the same type as the polarizer 36.
- the output of the photoelectric converter 46 is supplied to a signal processing system 104 after being subjected to impedance conversion and preamplification by an operational amplifier 49, and is appropriately processed.
- the detection device DT of the present invention functions similarly even when the optical sensor 100 and the sensor head 102 are provided separately.
- the detection device DT In order to detect a wiring defect of the printed wiring board by the detection device DT of FIG. 5, the detection device DT is arranged so that the sensor 100 is in non-contact with and close to the printed wiring board 50 as shown in FIG. An AC voltage of 100 V and 50 kHz was applied to the 300 m wide wiring 52 of the printed wiring board 50. Then, the output signal of the operational amplifier 49 was passed through a band-pass filter to extract a 50 kHz component, which was applied to an oscilloscope 54. As a result, a signal synchronized with the AC voltage applied to the wiring 52 was observed.
- the detection device DT of FIG. 5 is arranged so that the sensor 100 is in a non-contact and close proximity on the simple matrix type liquid crystal display panel 50 ′, and the detection device DT of FIG.
- an AC voltage of 10 V and 60 kHz was applied to the transparent electrode 52 'having a width and the output signal of the operational amplifier 49 was observed with the oscilloscope 54, a signal synchronized with the AC voltage applied to the transparent electrode 52' was observed.
- the optical sensor 100 and the sensor head of the detection device DT The optical sensor 100 was fixed separately from the tip of the sensor head 102 with a working distance of 3 mm, and the ITO layer was wired as a ground electrode.
- the detection device DT was arranged so that the optical sensor 100 was in non-contact and close proximity to the integrated circuit package (for example, PGA) 50 mm, and an AC voltage of 100 V, 70 kHz was applied to the electrode 52 mm.
- the signal obtained from the operational amplifier 49 was passed through a bandpass filter 56 to extract a voltage component of 70 kHz, and this voltage component was amplified and then passed through an oscilloscope 54 and a mouth-in amplifier 54 '. A signal synchronized with the applied AC voltage was observed.
- a detection device using a photoreflector 48 (Hamamatsu Photonics, P 2826) as shown in FIG. 4 instead of the light source 30 and the photoelectric converter 46 in FIG. 5 was manufactured.
- a signal synchronized with the AC voltage applied to the wiring 52, the transparent electrode 52 ', and the electrode 52' was observed.
- the thinning of the wiring 52 of the printed wiring board 50 was detected by the detecting device DT of the present invention.
- a detection device DT provided with a condenser lens on the exit side of the IZ4 wavelength plate 38 and the entrance side of the analyzer 144 of the sensor head 102 of FIG. 5 was used. With this condensing lens, the laser light from the light source 30 was narrowed down to about 10 m.
- a narrow part of about 50 width is provided on a part of a wiring 52 of 250 m width on the printed wiring board 50, and this wiring 52 is 100 V, 80 kHz AC voltage was applied.
- the printed circuit board 50 is scanned by moving the detecting device DT close to the printed circuit board 50 using a plane moving device with an accuracy of ⁇ 1 m, and each position of the detecting device DT is read by an encoder. I did it.
- the signal output from the detection device DT is passed through a band-pass filter, and the output and the position information signal of the detection device DT from the encoder are converted to an AZD converter.
- the signal was converted into a digital signal by 8 and then processed by a signal processing unit 104 such as a computer and displayed as an image on a display.
- Figure 10 shows an example of the image displayed on the display.
- the signal processing unit 104 it was found that the FWHM (Full Widget Half Maximum) of the narrow portion of the wiring 52 was 61 m.
- a simple matrix type liquid crystal display panel 50 having a transparent electrode 52 having a width of 100 m and a width 1 A 'simple Matricaria box-type liquid crystal display panel 50 2 having a' 2 2 are arranged adjacent to each other, to form a liquid crystal display panel with a narrowing in the width of the pseudo-transparent electrode.
- one laser beam from the light source 30 was narrowed down to about 10 m by a condenser lens.
- the liquid crystal display panel was scanned by the detecting device DT using a plane moving device having an accuracy of ⁇ 1 zm, and each position of the detecting device DT was read by an encoder.
- a measurement was performed to detect the presence or absence of a short circuit between the source and the drain and between the gate and the drain of the TFT-active matrix liquid crystal display panel.
- 100 m wide scanning electrodes (gate lines) XI, X2, X3 and signal electrodes (source lines) Yl, ⁇ 2, ⁇ 3 are arranged in a grid pattern as a simulated liquid crystal display panel.
- a panel was used in which the transparent pixel electrode ⁇ and the signal electrode Y1 were connected by a thin wire as shown in a, and the signal electrode (source line) or the drain line and the pixel electrode were short-circuited.
- an AC signal of 5 V, 70 kHz was applied to the signal electrode Y1, and the panel was scanned by the detector DT.
- the signal obtained from the detection device DT is passed through a band-pass filter, and further, the output together with the position information signal from the encoder is converted into a digital signal by the AZD converter 58, and the output is then processed by the signal processing unit.
- Processed at 104 and displayed as an image on the display.
- FIG. 14 shows an image obtained by this measurement. In this application example, it was confirmed that a potential was generated at the pixel electrode A shorted to the signal electrode Y1.
- a short circuit between the source and gate of the TFT, a short circuit at the intersection of the signal electrode and the scan electrode, and a disconnection of the electrode at any point on the LCD panel were detected.
- a defect occurs, it is considered that no potential is actually applied to the pixel electrode even when a normal voltage is applied so that a voltage is applied to the pixel electrode. Therefore, in this application example, a simulated panel in which all pixel electrodes are connected to the corresponding signal electrodes Yl, ⁇ 2, ⁇ 3 with wires, and only one of the pixel electrodes ⁇ is cut as shown in b was used.
- the detection device DT was used to measure whether or not a short circuit due to dielectric breakdown occurred during a withstand voltage test on a printed wiring board on which two wirings having a width of 100 m were formed at intervals of 1 m. For this purpose, an AC voltage of 1 kHz is applied to one of these wires, and the voltage is raised from 50 V to 500 V while the detection device DT scans over the printed wiring board. As a result, it was observed that at about 450 V, a short circuit occurred between the wires due to dielectric breakdown, and a voltage was also generated in the wires to which no voltage was applied.
- the disconnection of the integrated circuit package 50 mm was detected.
- the optical sensor 100 was diced to 100 ⁇ 10 mm and fixed close to the integrated circuit package 50 °, and the ground electrode was grounded by a wire. In this case, light sensor 1 0
- step 02 the signal is converted into an electric signal and amplified, and only a signal component of 70 kHz is extracted by a band-pass filter 64.
- the extracted signal components were converted to direct current by the RMS ZDC converter 66, and the signal strength of the 70 kHz signal component was displayed on a storage oscilloscope 54 ⁇ .
- FIG. 17 shows an example of the pattern thus displayed.
- the horizontal axis represents time
- the vertical axis represents signal strength.
- This pattern indicates that no signal is generated from the electrode to which no AC voltage is applied (grounded), and it is necessary to detect a broken wire part by comparing the displayed pattern with the original wiring pattern. It was confirmed that it could be done.
- the FWHM averaged 102 and was found to match the actual wiring width.
- the detection device DT shown in FIG. 5 Using the detection device DT shown in FIG. 5, a measurement was performed to detect the presence or absence of a short-circuit point in the integrated circuit package 50 ⁇ . For this purpose, as shown in Fig. 18, any two pins of the integrated circuit package 50 ⁇ ⁇ are connected with a wire and short-circuited, and an AC voltage is applied to one of these pins. did. In this way, the detection device DT is moved on the integrated circuit package 50 ⁇ by the movement device 60, and the signals obtained by the detection device DT are processed in the same manner and displayed on the display. The pattern shown in FIG. 19 is obtained. Was done. Here, the horizontal axis represents time, and the vertical axis represents signal strength. From this pattern, it was confirmed that a short-circuited electrode could be detected. Industrial applicability
- the present invention provides a method for disconnecting various wiring boards such as a printed wiring board, a liquid crystal display panel, and a package for an integrated circuit.
- This provides a special effect that the presence and occurrence of defects such as thinning and short-circuit can be detected in a non-contact manner in a short time.
- the present invention is applied to a multilayer printed wiring board, defects existing in all layers can be simultaneously eliminated. There is an effect that detection can be performed. In addition, the detection of defects in the liquid crystal display panel is possible even when the alignment film is applied.
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- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP95903937A EP0752583A4 (en) | 1993-12-24 | 1994-12-22 | DEVICE FOR DETECTING A WIRING FAULT IN A WIRING SUBSTRATE |
JP7517894A JP2983294B2 (ja) | 1993-12-24 | 1994-12-22 | 配線基板の配線の欠陥を検出する装置 |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5/328082 | 1993-12-24 | ||
JP32808293 | 1993-12-24 | ||
JP6/93396 | 1994-05-02 | ||
JP9339694 | 1994-05-02 |
Publications (1)
Publication Number | Publication Date |
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WO1995018369A1 true WO1995018369A1 (fr) | 1995-07-06 |
Family
ID=26434776
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP1994/002189 WO1995018369A1 (fr) | 1993-12-24 | 1994-12-22 | Dispositif de detection d'un defaut de cablage dans un substrat de cablage |
Country Status (2)
Country | Link |
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EP (1) | EP0752583A4 (ja) |
WO (1) | WO1995018369A1 (ja) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0437825A (ja) * | 1990-06-04 | 1992-02-07 | Seiko Epson Corp | 液晶電気光学装置 |
JPH0587839A (ja) * | 1991-09-27 | 1993-04-06 | Matsushita Electric Ind Co Ltd | 電圧分布測定方法 |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1991003683A1 (en) * | 1989-09-11 | 1991-03-21 | Hoechst Celanese Corp | Acrylic copolymers exhibiting nonlinear optical response |
US5258705A (en) * | 1990-12-21 | 1993-11-02 | Sharp Kabushiki Kaisha | Active matrix substrate inspecting device |
DE4213155A1 (de) * | 1991-04-29 | 1992-11-05 | Sandoz Ag | Verbindungen mit nichtlinearen optischen eigenschaften |
US5171803A (en) * | 1991-05-24 | 1992-12-15 | Hoechst Celanese Corp. | Copolymer with side chains exhibiting nonlinear optical response |
-
1994
- 1994-12-22 WO PCT/JP1994/002189 patent/WO1995018369A1/ja not_active Application Discontinuation
- 1994-12-22 EP EP95903937A patent/EP0752583A4/en not_active Withdrawn
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0437825A (ja) * | 1990-06-04 | 1992-02-07 | Seiko Epson Corp | 液晶電気光学装置 |
JPH0587839A (ja) * | 1991-09-27 | 1993-04-06 | Matsushita Electric Ind Co Ltd | 電圧分布測定方法 |
Non-Patent Citations (1)
Title |
---|
See also references of EP0752583A4 * |
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EP0752583A4 (en) | 1997-05-07 |
EP0752583A1 (en) | 1997-01-08 |
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