Semiconductor device inspection system

• US 4,872,052 A
• Filed: 12/03/1987
• Issued: 10/03/1989
• Est. Priority Date: 12/03/1986
• Status: Expired due to Term

• Current Assignee: GSI Lumonics Corporation (Novanta Inc.), Kaijo Denki Co., Ltd. (Shibuya Corporation)
• Original Assignee: View Engineering, Inc. (Quality Vision International, Inc.), Kaijo Denki Co., Ltd. (Shibuya Corporation)
• Inventors: Weisner, Ralph M., Uramoto, Iwami, Liudzius, Valerie A., Kamiharako, Takashi
• Primary Examiner(s): Peng, John K.
• Application Number:
  US07/128,329
• Time in Patent Office: 670 Days
• Field of Search: 358/106, 358/101, 358/107, 358/88, 350/511, 350/513, 350/514, 350/515, 350/520-522, 356/237, 356/394, 382/8
• US Class Current: 348/126
• CPC Class Codes: G01N 2021/8887 based on image processing techniques
• CPC Class Codes: G01N 2021/95615 with stored comparision signal
• CPC Class Codes: G01N 21/956 Inspecting patterns on the surface of objects contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G01N 2201/102 Video camera
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/4809 Loop shape
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/78 Apparatus for connecting with wire connectors
• CPC Class Codes: H01L 2224/859 involving monitoring, e.g. feedback loop
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/78 Apparatus for connecting with wire connectors
• CPC Class Codes: H01L 24/85 using a wire connector wire bonding in general B23K20/004
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

A semiconductor device inspection system capable of objectively accomplishing visual image inspection of a semiconductor device and minimizing error in the inspection, to thereby effectively carry out the inspection with high accuracy and at high speed. The system includes a low magnification image pickup mechanism which consists of a plurality of low magnification image pickup units each carrying out low magnification image pickup of a semiconductor device to generate an image signal. The system also includes a signal processing system for processing the image signal to judge the correctness of the semiconductor device. In the image pickup units, their light receptors are each arranged in parallel to an inspected surface of the semiconductor device and their central axes intersect together on the inspected surface. The system may also include a high magnification image pickup unit consisting of a high magnification image pickup mechanism and a light-permeable element retractably positioned between the unit and a semiconductor device to be inspected.

Claims

1. A semiconductor device inspection system for carrying out visual image inspection of a semiconductor device subjected to wire bonding and supported on a base, comprising:

at least one image pickup mechanism comprising;

a plurality of image pickup units each of which carries out image pickup of said semiconductor device to generate an image signal, said image pickup units each including a lens system having at least one lens and a light receptor for receiving thereon an image formed by said lens system;

an optical-electrical signal converter means connected to said image pickup units for converting each of said image signals into an electrical signal;

an operation circuit connected to said optical-electrical signal converter to digitize said electrical signal, said operation circuit digitizing electrical signals derived from at least two of said image pickup units and converted by said converter and synthetically operating the digitized of an inspected section of said semiconductor device;

a memory circuit for storing digitized standard data on an inspection item therein; and

an image processing unit connected to said operation circuit to compare an input data signal obtained by digitizing said electrical signal with a standard data signal based on said digitized standard data to judge the normality of said input data signal;

said image pickup units being arranged in a manner such that central axes of said image pickup units each defined by connecting a center of said light receptor and a center of said lens system together intersect one another on said inspected surface of said semiconductor device, consequently, the central axis of at least one image pickup unit is oblique to said inspected surface of said semiconductor device, and that, said light receptor of each of said image pickup units, including said at least one oblique image pickup unit, is arranged in parallel to an inspected surface of said semiconductor device.

2. A semiconductor device inspection system as defined in claim 1, wherein said image pickup mechanism is a low magnification image pickup mechanism.

3. A semiconductor device inspection system as defined in claim 2 further comprising a high magnification image pickup mechanism connected to said optical-electrical signal converter means.

4. A semiconductor device inspection system as defined in claim 3, wherein said high magnification image pickup mechanism comprises a high magnification image pickup unit and a light-permeable element having a refractive index different from that of air;

said light-permeable element being arranged in a manner to be retractably interposed between said high magnification image pickup unit and said semiconductor device.

5. A semiconductor device inspection system as defined in claim 1, wherein said lens system is arranged in a manner such that a lens plane thereof perpendicular to a lens axis is parallel to said inspected surface of said semiconductor device.

6. A semiconductor device inspection system for carrying out visual image inspection of a semiconductor device subjected to wire bonding and supported on a base, comprising:

a loading mechanism for receiving therein a semiconductor device on which wire bonding has been completed;

a transfer mechanism for transferring the semiconductor device fed from said loading mechanism through an inspection stage;

an unloading mechanism for receiving the semiconductor device discharged from said transfer mechanism;

an image pickup means for carrying out image pickup of an inspected surface of the semiconductor device on said inspection stage to generate and image signal wherein said image pickup means comprises a low magnification image pickup mechanism and a high magnification image pickup mechanism and said image pickup means is oblique to said inspected surface of said semiconductor device;

a memory circuit for storing standard data therein;

an image processing unit connected between said image pickup means and said memory circuit to carry out digital processing of said image signal and compare said digitized image signal with said standard data stored in said memory circuit to judge the correctness of said wire bonding and generate a judgment signal; and

a marking mechanism of carrying out marketing indicative of the correctness of the semiconductor device depending on said judgment signal from said image processing unit.

7. A semiconductor device inspection system as defined in claim 6, wherein said low magnification image pickup mechanism has a visual field which covers an IC chip and a whole circumference thereof and said high magnification image pickup mechanism has a visual field which covers a pad or lead and a circumference thereof.

8. A semiconductor device inspection system comprising:

a base for holding a semiconductor device thereon; and

an image pickup mechanism for carrying out plane image pickup of said semiconductor device to inspect a visual image of said semiconductor device;

said image pickup mechanism comprising an image pickup unit and a light-permeable element having a refractive index different from that of air;

said light-permeable element being arranged in a manner to be retractably interposed between said image pickup unit and said semiconductor device.

9. A semiconductor device inspection system as defined in claim 8, wherein said image pickup unit generates a signal indicating the result of said image pickup.

11. A semiconductor device inspection system as defined in claim 8, wherein said light-permeable element comprises a flat glass plate.

12. A semiconductor device inspection system as defined in claim 11, wherein said glass plate has surfaces parallel to each other.

13. A semiconductor device inspection system as defined in claim 12, wherein said glass plate is provided on one of said surfaces with at least one step so that it may be divided into a plurality of sections different in thickness from each other.

14. A semiconductor device inspection system as defined in claim 12, wherein one of said surfaces of said glass plate is inclined to cause the thickness of said glass plate to be gradually and continuously varied.

15. A semiconductor device inspection system as defined in claim 8, wherein said image pickup mechanism is arranged so as to be horizontally moved in X and Y directions.

16. A semiconductor device inspection system as defined in claim 15, wherein said light-permeable element is supported on said image pickup unit.

17. A semiconductor device inspection system as defined in claim 16, wherein said light-permeable element is supported on said image pickup unit through a holder which is mounted on said image pickup mechanism, to thereby be pivotally moved about a vertical axis.

10. A semiconductor device inspection system as defined in claim 10 further comprising a signal processing means connected to said image pickup mechanism to process said signal for inspection.

18. A semiconductor device inspection system comprising:

a base for holding a semiconductor device thereon;

an image pickup mechanism for carrying out plane image pickup of said semiconductor device to generate a signal indicating the result of said plane image pickup, said image pickup mechanism being arranged so as to be horizontally moved in X and Y directions; and

a signal processing means connected to said image pickup mechanism to process said signal generated from said image pickup mechanism for inspection;

said image pickup mechanism comprising an image pickup unit and a light-permeable element supported on said image pickup unit and having a refractive index different from that of air;

said light-permeable element being arranged in a manner such that it is pivotally moved about a vertical axis so as to be retractably positioned between said image pickup unit and said semiconductor device.