EP0446838A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of and apparatus for inspection of bonding wire
Assignee: Fujitsu Ltd
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Filing: 1991-03-11
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Granted: —
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Expires: 2011-03-11
Abstract
Abstract An optical system for inspecting bonding wires (70) on a semiconductor has a camera (1), focal length and depth adjusting means (2), an illumination device (4) for irradiating brilliantly a desired portion of an inspection object (7) with an illumination light. The focal length and depth adjusting means (2) comprises a plurality of glass plates (21, 22, ... 24) each having a different focal length and depth, and each bonding wire (70) is inspected at a plurality of levels (F 1 , F 2 , F 3 ) in height position of the wire (70) and at a plurality of portions (P, Q) thereof in its longitudinal direction to make a comparison between focal point evaluation quantities (E) at each detected position whereby wiring defects can be detected.
Inventors
- 👤 Hiroyuki Tsukahara
- 👤 Yoshitaka Oshima
- 👤 Masato Nakashima
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-10 02:20
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/28; G01R31/302; G01R31/308; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/956; G01N21/95684; G01N21/17; G01N2021/178; G01N2021/1782; G01N21/8851; G01N2021/8887; G01N2201/00; G01N2201/10; G01N2201/102; H; H10; H10W; H10W72/00; H10W72/071; H10W72/0711; H10W72/075; H10W72/07531; H10W72/50; H10W72/531; H10W72/536; H10W72/5363; H10W72/541; H10W72/5449; H10W72/551; H10W72/552; H10W72/5522; H10W72/5524; H10W72/90; H10W72/931; H10W72/932
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
238 words
A method of inspection of bonding wires (70) on a semiconductor as an inspection object (7) in which a camera (1) captures an image of said inspection object (7) while irradiating it with an illumination light to obtain a video signal which is to be processed to detect wiring defects, characterized in that said method comprises the steps of: a) determining a plurality of combinations with respect to focal depth and length of said camera (1); b) capturing an image of at least one selected portion (P, Q) of a bonding wire (70) with a combination of a certain focal length and a certain depth to obtain a feature quantity on the basis of luminance distribution at said portion (P, Q) thereof in a certain height of said wire (70), respectively; c) capturing an image at said portion of the bonding wire (70) with a combination of another focal length different from said certain focal length and a certain depth to obtain a feature quantity on the basis of luminance distribution at said portion thereof in another height position of said wire, a similar image capture operation being repeated, a predetermined number of times, with a different focal length and depth in a different height position of said wire (70); and d) making a comparison between a plurality of feature quantities at said portion at different height positions (F₁, F₂, F₃) of said wire to detect wiring defects.
Claim 2
Dependent Claim
93 words
A method according to claim 1, wherein at least four combinations of said focal depth and length are determined, these combinations being such that a first combination of a first short focal length (f₁) and a first small focal depth (δ₁), a second combination of a second intermediate focal length (f₂) and a first small focal depth (δ₁), a third combination of a second intermediate focal length (f₃) and a second large focal depth (δ₂), and a fourth combination of a third long focal length (f₄) and a first small focal depth (δ₁).
Claim 3
Dependent Claim
121 words
A method according to claim 1 or 2, wherein two portions of said wire are selected to capture those images, one portion (P) being near a top portion of said wire and the other portion being intermediate portion (Q) thereof, at least three levels (F₁, F₂, F₃) being set with respect to height position of said wire, a first level (F₁) being set at a position over said top portion of the wire, a second level (F₂) being set at an intermediate height position thereof, a third level (F₃) being set at a lower portion of said inspection object (7), said camera (1) being adjusted so that three focal lengths (f₁, f₂, f₃) coincide with three levels (F₁, F₂, F₃), respectively.
Claim 4
Dependent Claim
85 words
A method according to claim 2, wherein an image of said wire is, firstly, captured with a second intermediate focal length (f₂) corresponding to an intermediate height position of said wire and a second large focal depth (δ₂) including said top portion of the wire and said lower portion of the inspection object (7) to detect existence of said wire, and images of said two portions thereof are, secondly, captured with other different focal lengths (f₁, f₂, f₃) and the first small focal depth (δ₁).
Claim 5
Independent Claim
30 words
A method according to any preceding claim, wherein said feature quantity is a ratio (W/B) of a height of a peak of luminance distribution to a width of said peak.
Claim 6
Independent Claim
136 words
An apparatus for inspection of bonding wires (70) on a semiconductor as an inspection object (7) in which a camera (1) captures an image of said inspection object while irradiating it with an illumination light to obtain a video signal which is to be processed to detect wiring defects, characterized in that said apparatus comprises; a) focal length and depth adjusting means (2) provided between said inspection object (7) and said camera (1); b) feature quantity extraction means (15) for extracting feature quantities (E) at at least one selected point (P, Q) of said wire on the basis of luminance distribution at said point; and c) judgement means (16) for making a comparison between said feature quantities (E) at different height positions of said wire at said selected point (P, Q) thereof to detect wiring defects.
Claim 7
Dependent Claim
68 words
An apparatus according to claim 6, wherein said focal length and depth adjusting means (2) comprises a frame (20) which is rotated about its center axis and provided with a plurality of glass plates (21, 22, 23, 24) each having a predetermined focal length and depth and arranged annularly, each glass plate being moved so that its axis coincides with an optical axis (11) of said camera (1).
Claim 8
Dependent Claim
88 words
An apparatus according to claim 7, wherein said glass plates comprises at least a first glass plate (21) with a first short focal length (f₁) and a first small depth (δ₁), a second glass plate (22) with a second intermediate focal length (f₂) and a first small focal depth (δ₁), a third glass plate (23) with a second intermediate focal length (f₂) and a second large focal depth (δ₂), and a fourth glass plate (24) with a third long focal length (f₃) and a first focal depth (δ₁).
Claim 9
Dependent Claim
83 words
An apparatus according to claim 6, 7 or 8, further comprising an illumination device (4) for irradiating said inspection object (7) with an illumination light, which has an annular illumination unit (5, 120) for emitting said illumination light in an annular shape, an optical path changing unit (10, 300, 400, 500, 600, 601) for directing said illumination light to said inspection object (7) located in said optical path changing unit, and a driving unit (211) for moving vertically said optical path changing unit.
Claim 10
Dependent Claim
30 words
An apparatus according to claim 9, wherein said driving unit comprises a stopper (13a, 13b) for stopping said optical path changing unit at an upper and a lower limit positions.
Claim 11
Dependent Claim
119 words
An apparatus according to claim 6, 7 or 8, further comprising an illumination device for irradiating said inspection object with an illumination light, which has an annular illumination unit (5) for emitting said illumination light in an annular shape, and an optical path changing unit (10) for directing said illumination light to said inspection object (7) located in said optical path changing unit (10), said optical path changing unit comprising an annular reflecting mirror (300) which has an inner inclined reflecting surface composed of a plurality of linear surfaces (303a, 303b, 303c) each having a different inclination angle (ϑ₁, ϑ₂, ϑ₃) for condensing said illumination light to an upper portion of said wire more than a lower portion thereof.
Claim 12
Independent Claim
104 words
An apparatus according to any of claims 6 to 10, further comprising an illumination device for irradiating said inspection object (7) with an illumination light, which has an annular illumination unit for emitting said illumination light in an annular shape, and an optical path changing unit (10) for directing said illumination light to said inspection object (7) located in said optical path changing unit (10), said optical path changing unit comprising an annular reflecting mirror (400) which has an inner reflecting smoothly curved surface (401) for condensing said illumination light to an upper portion of said wire (70) more than a lower portion thereof.
Claim 13
Independent Claim
100 words
An apparatus according to any of claims 6 to 10, further comprising an illumination device for irradiating said inspection object (7) with an illumination light, which has an annular illumination unit for emitting said illumination light in an annular shape, and an optical path changing unit (10) for directing said illumination light to said inspection object (7) located in said optical path changing unit (10), said optical path changing unit comprising an annular reflecting prism (500) which has a reflecting surface (501) for condensing said illumination light to an upper portion of said wire more than a lower portion thereof.
Claim 14
Independent Claim
106 words
An apparatus according to any of claims 6 to 10, further comprising an illumination device for irradiating said inspection object with an illumination light, which has an annular illumination unit for emitting said illumination light in an annular shape, and an optical path changing unit (10) for directing said illumination light to said inspection object located in said optical path changing unit, said annular illumination unit (5, 120) comprising a number of glass fibers (9) which are arranged annularly and whose light emitting ends (9b) are formed so as to decrease a diverging angle (ϑd), an annular reflecting mirror (600) having an inner inclined linear surface.
Claim 15
Independent Claim
128 words
An apparatus according to any of claims 6 to 8, further comprising an illumination device for irradiating said inspection object with an illumination light, which has an annular illumination unit for emitting said illumination light in an annular shape, an optical path changing unit (10) for directing said illumination light to said inspection object located in said optical path changing unit (10), and at least one of a vertical illumination unit (101) for throwing an illumination light onto said inspection object from above and a back illumination unit (102) for irradiating back surface of said inspection object (7) from back with an illumination light, each of said vertical and back illumination units having a shutter (105, 121) for controlling travel of illumination light emitted from a light source.
Claim 16
Independent Claim
23 words
An apparatus according to any of claims 6 to 15, said camera comprises a line sensor (814) for scanning over said inspection object.
Claim 17
Independent Claim
124 words
An apparatus for inspection of bonding wires on a semiconductor as an inspection object (7) in which a camera (1) captures an image of said inspection object while irradiating it with an illumination light to obtain a video signal which is to be processed to detect wiring defects, characterized in that said apparatus comprises an illumination device (4, 100) for irradiating said inspection object (7) with an illumination light, which has an annular illumination unit (5, 120) for emitting said illumination light in an annular shape, an optical path changing unit (10, 300, 400, 500, 600) for directing said illumination light to said inspection object located in said optical path changing unit, and a driving unit (211) for moving vertically said optical changing unit.
Claim 18
Dependent Claim
31 words
An apparatus according to claim 17, wherein said driving unit (211) comprises stoppers (13a, 13b) for stopping said optical path changing unit (10) at an upper and a lower limit positions.
Claim 19
Dependent Claim
63 words
An apparatus according to claim 17 or 18, wherein said optical path changing unit comprises an annular reflecting mirror (300) which has an inner inclined reflecting surface (303) composed of a plurality of linear surfaces (303a, 303b, 303c) each having a different inclination angle for condensing said illumination light to an upper portion of said wire more than to a lower portion thereof.
Claim 20
Dependent Claim
48 words
An apparatus according to claim 17 or 18, wherein said optical path changing unit comprises an annular reflecting mirror (400) which has an inner reflecting smoothly curved surface (401) for condensing said illumination light to an upper portion of said wire more than to a lower portion thereof.
Claim 21
Dependent Claim
45 words
An apparatus according to claim 17 or 18, wherein said optical path changing unit comprises an annular reflecting prism (500) which has a reflecting surface (501) for condensing said illumination light to an upper portion of said wire more than to a lower portion thereof.
Claim 22
Dependent Claim
50 words
An apparatus according to claim 17 or 18, wherein said annular illumination unit comprises a number of glass fibers (9) which are arranged annularly and whose light emitting ends are formed so as to decrease a diverging angle (ϑd), an annular reflecting mirror (600) having an inner inclined linear surface.
Claim 23
Independent Claim
78 words
An apparatus according to any of claims 17 to 22, further comprising at least one of a vertical illumination unit (101) for throwing an illumination light onto said inspection object from above and a back illumination unit (102) for irradiating back surface of said inspection object from back with an illumination light, each of said vertical and back illumination units (101, 102) having a shutter (105, 121) for controlling travel of illumination light emitted from a light source.
Claim 24
Dependent Claim
21 words
An apparatus according to claim 17, said camera (1) comprises a line sensor (813) for scanning over said inspection object (7).
References Cited (Backward Citations)
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