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Browse Prior Art Database

Pin Hole Detection in Films by Voltage Breakdown

IP.com Disclosure Number: IPCOM000042523D
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Hollis, RL: AUTHOR

Abstract

This is a method based on ionization of gas by means of a sharp probe to detect pin hole defects in films of the type used in semiconductor and semiconductor package devices. Pin holes in thin films (such as polyimide) used for package dielectrics can be found by this voltage breakdown method, which employs a pointed high-voltage probe scanned over a film deposited on a ground plane. The sample and probe are surrounded by a suitable gas with controlled breakdown characteristics. During scanning, current from the probe is monitored. Increases in current indicate areas of gas ionization associated with the pin hole sites. The method may find general areas of pin holes, and automated search procedures can determine exact locations.

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Pin Hole Detection in Films by Voltage Breakdown

This is a method based on ionization of gas by means of a sharp probe to detect pin hole defects in films of the type used in semiconductor and semiconductor package devices. Pin holes in thin films (such as polyimide) used for package dielectrics can be found by this voltage breakdown method, which employs a pointed high-voltage probe scanned over a film deposited on a ground plane. The sample and probe are surrounded by a suitable gas with controlled breakdown characteristics. During scanning, current from the probe is monitored. Increases in current indicate areas of gas ionization associated with the pin hole sites. The method may find general areas of pin holes, and automated search procedures can determine exact locations. The electric field at the tip of a charged pointed probe 10 can be several orders of magnitude greater than the field associated with the smooth sides of the probe, as illustrated in Fig. 1(a). If the probe 10 is placed in close proximity to a planar surface 7, such as an infinite half-plane 8 covered with a thin insulator 9, the field lines are modified, but the maximum field remains at the probe tip Fig l(b). For a number of elemental gases and gas mixtures, such as air, the field is great enough for ionization to occur, creating the potential for formation of a conducting pathway. The actual breakdown voltage is a function of the probe-sample spacing, gas composition, and gas pressure. Optimum pressures for minimum breakdown voltages exist. Gases which break down within Paschen's law regime include air, nitrogen, hydrogen, argon and neon. The dielectric streng...