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Method for Detecting Flux-on-Die Presence Through Reflective Emission of UV Lighting

IP.com Disclosure Number: IPCOM000011938D
Publication Date: 2003-Mar-26
Document File: 3 page(s) / 90K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that uses an automated vision system with an ultraviolet lighting source to detect the presence or absence of flux on the back-side of the die surface. The system also detects the percentage of flux coverage on the back-side of the die surface. Benefits include real-time monitoring.

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Method for Detecting Flux-on-Die Presence Through Reflective Emission of UV Lighting

Disclosed is a method that uses an automated vision system with an ultraviolet lighting source to detect the presence or absence of flux on the back-side of the die surface. The system also detects the percentage of flux coverage on the back-side of the die surface. Benefits include real-time monitoring.

Background

Flux monitoring is currently performed by weight dispensation. The weight dispensed indicates the presence or absence to a degree, but does not address the percentage of surface area covered.

General Description

The disclosed method uses a Cognex vision sensor attached to a one-meter conveyor placed after flux dispense (see Figure 1).� The lighting source uses a high-intensity ultraviolet light to allow the flux dispensed to fluoresce against the background of the die surface. Controlling the ambient lighting is required in this particular application. This method allows the vision system to detect the presence and absence of flux as well as percentage of coverage.�

Figure 2 shows a picture of samples taken with ultraviolet light (with no ambient lighting interfering with the image). The samples have been partially dispensed with flux, and the vision system is clearly capturing presence/absence and percentage of coverage.� Through programming boundary conditions, alarms are placed to obtain the desired monitor result as well as area coverage. The following is the set-up for the Flux UV Detection System:

 

  1. The vision sensor (camera), is located above a 1-meter c...