# US 5,347,362 A · Bonding wire inspection method

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- Number: US 5,347,362 A
- Document ID: US5347362A
- Status: Granted
- Kind: A
- Application number: 07/983,661
- Filed: 1992-12-01
- Granted: 1994-09-13
- Earliest claimed: 1991-12-02
- Assignees: Kabushiki Kaisha Shinkawa
- Inventors: Kenji Sugawara
- Web page: https://patentgrep.com/patent/US5347362A

## CPC

- G01R 31/2853: {Electrical testing of internal connections or -isolation, e.g. latch-up or chip-to-lead connections (G01R31/31717 takes precedence; test of chip-to-PCB or lead-to-PCB connections G01R31/66)}
- G01N 21/95684: {Patterns showing highly reflecting parts, e.g. metallic elements}
- H10W 72/0711: {Apparatus therefor}
- H10W 72/07531: {Techniques}
- H10W 72/07553: {changes in shapes}
- H10W 72/531: {Shapes of wire connectors}
- H10W 72/536: {the connected ends being ball-shaped}
- H10W 72/5363: {the connected ends being wedge-shaped}
- H10W 72/5449: {not being orthogonal to a side surface of the chip, e.g. fan-out arrangements}
- H10W 72/5522: {comprising gold [Au]}
- H10W 72/59: Bond pads specially adapted therefor
- H10W 72/884: {Die-attach connectors and bond wires}
- H10W 72/932: {Plan-view shape, i.e. in top view}
- H10W 90/756: {between a chip and a stacked lead frame, conducting package substrate or heat sink}
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A method of inspecting wires bonded between the pads of a semiconductor chip and the leads of a lead frame taking the steps of: bringing the focus of an optical assembly into a desired point of a bonded wire, thus obtaining the height of such a desired point of the wire as a reference; photographing an image of the wire at the reference height; and then obtaining the height of the wire based upon the amount of the indistinct image of the photographed wire.

## Claims

### Claim 1

A method of inspecting wires bonded between pads of a semiconductor chip and leads of a lead frame, said method comprising the steps of:
moving a single optical means in a Z direction to focus said single optical means onto a surface of a semiconductor chip with a desired lead and desired bonding wire within an image field of said single optical means, said single optical means comprising a low magnification camera with a shallow depth of focus;
photographing an indistinct image of said desired bonding wire;
measuring a width of said indistinct image of said desired bonding wire;
moving said single optical means in said Z direction to focus said single optical means onto a lead;
photographing an indistinct image of said desired bonding wire;
measuring a width of said indistinct image of said desired bonding wire; and
calculating a height of said desired bonding wire from said measured widths of said indistinct image of said desired bonding wire when said single optical means is focused on said surface of said semiconductor chip and focused onto said lead;
whereby a more precise measurement of the height of said bonding wire is made.

### Claim 2 (depends on 1)

The method of according to claim 1 further comprising a ring form illumination means for illuminating said semiconductor chip, bonding wire and lead.

### Claim 3 (depends on 1)

The method according to claim 1, wherein a width of said indistinct image is measured at a plurality of locations and a plurality of heights of said bonding wire are calculated from said plurality of measurements.