Browse Prior Art Database

Masking Technique

IP.com Disclosure Number: IPCOM000089966D
Original Publication Date: 1968-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 80K

Publishing Venue

IBM

Related People

Dhaka, VA: AUTHOR [+3]

Abstract

This technique utilizes a masking layer of silicon nitride to control locations of contact holes in a passivation layer. All openings, particularly the base contact and emitter diffusion openings, can be located in a single operation with a single mask.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 58% of the total text.

Page 1 of 2

Masking Technique

This technique utilizes a masking layer of silicon nitride to control locations of contact holes in a passivation layer. All openings, particularly the base contact and emitter diffusion openings, can be located in a single operation with a single mask.

In the fabrication of high-performance semiconductor transistors in which the entire emitter diffusion opening is used for an emitter contact, two separate masking operations are utilized. The first operation defines the emitter opening while the second operation defines base contact holes. When the relative registration of the separate masking operations is not precise the subsequent metallurgy layer connected to the device cannot be made.

After base diffusion 10 is made through an opening in SiO(2) layer 12, the cross-section is as in A. Collector contact hole 32 is etched in layer 12. In this method, a thin layer 14 of SiO(2) is subsequently deposited over layer 12. An overlying layer 16 of silicon nitride is grown over layer 14. A second layer 18 of SiO(2) deposited over layer 14. A resist layer 20 is formed over the composite layer and the openings for the collector, emitter and base formed by single masking operation. Openings are then made through layers 16 and 18. Si(3)N(4) layer 16 is etched using layer 18 as a mask. At this point, all openings, in particular the emitter and base openings, are geometrically defined by the apertures in Si(3)N(4) layer except for the initial layer 14.

An a...