Browse Prior Art Database

Chip Personalization by Short Laser Pulses

IP.com Disclosure Number: IPCOM000082147D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Cook, PW: AUTHOR [+5]

Abstract

Interconnections for integrated circuits may be made directly through a dielectric separating metallization and an underlying region of semiconductor material, by a focused laser without opening via holes. For example, aluminum interconnecting lines (approximately 10,000 angstroms thick) may be connected to an underlying P-type conductivity diffusion region in a silicon substrate, by subjecting the aluminum to one or more short pulses of light (8 nanoseconds or less) from a nitrogen laser pumped dye laser.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Chip Personalization by Short Laser Pulses

Interconnections for integrated circuits may be made directly through a dielectric separating metallization and an underlying region of semiconductor material, by a focused laser without opening via holes. For example, aluminum interconnecting lines (approximately 10,000 angstroms thick) may be connected to an underlying P-type conductivity diffusion region in a silicon substrate, by subjecting the aluminum to one or more short pulses of light (8 nanoseconds or less) from a nitrogen laser pumped dye laser.

When this is done, the aluminum is mostly ablated, resulting in optical absorption and localized heating in the silicon semiconductor. The silicon wells up to form a connection with the aluminum through the dielectric (SiO(2)) (approximately 10,000 angstroms thick) which is transparent to the laser light. Subsequent annealing of the interconnection reduces contact resistance to approximately 50 ohms.

While this connection is ohmic, it should be appreciated that, under the same conditions, a contact formed with an underlying N-type conductivity diffusion region in silicon forms a connection having diode characteristics.

The above-described interconnection technique may be utilized with other metals, dielectrics and semiconductors except that the width of the laser pulses utilized and the wavelength of the laser may have to be varied, due to the different characteristics of the materials involved.

1