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Automated High Density Multiple Small Hole Verification System

IP.com Disclosure Number: IPCOM000088645D
Original Publication Date: 1977-Jul-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Haas, RG: AUTHOR [+2]

Abstract

In the manufacture of multilayer ceramic (MLC) substrates for integrated-circuit semiconductor package structures, a plurality of ceramic green sheets must be punched to form via holes, metallizing paste deposited in the holes and in appropriate patterns on the surface formed, the sheets stacked, and subsequently fired at a sintering temperature. The holes are conventionally formed with a punch. In a typical MLC product, ceramic sheets can have thousands of holes each with a diameter as small as .005 inch. Product quality requires 100% good holes. Conventional inspection techniques involve 100% operator visual inspection. This type of inspection is unreliable over a long period of time in a production environment.

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Automated High Density Multiple Small Hole Verification System

In the manufacture of multilayer ceramic (MLC) substrates for integrated- circuit semiconductor package structures, a plurality of ceramic green sheets must be punched to form via holes, metallizing paste deposited in the holes and in appropriate patterns on the surface formed, the sheets stacked, and subsequently fired at a sintering temperature. The holes are conventionally formed with a punch. In a typical MLC product, ceramic sheets can have thousands of holes each with a diameter as small as .005 inch. Product quality requires 100% good holes. Conventional inspection techniques involve 100% operator visual inspection. This type of inspection is unreliable over a long period of time in a production environment.

A hole verification system is useful in conjunction with a programmed hole punching device utilizing a computer control. This hole punching verification system can utilize the same computer output to verify the apertures in a green sheet similar to the one that is being punched. The same corresponding holes are verified that are being punched in a corresponding sheet.

The basic concept used is shining light through the product which is sensed by a photodiode to indicate whether or not the hole is clear. This is Illustrated in Fig. 1 where light from a fiber-optic element 10 passes through an opening 11 in a first aperture plate 12 through a punched opening 13 in green sheet product
14. If the opening in hole 13 is clear the light will continue through a second opening 15 in...