Browse Prior Art Database

Wafer Island Isolation Technique

IP.com Disclosure Number: IPCOM000083665D
Original Publication Date: 1975-Jul-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Hoffman, WK: AUTHOR [+4]

Abstract

An island 10 in a silicon wafer 12, indicated in Fig. 1, is tested before any circuits or lines 14, such as power or phase lines, from that island are connected to other islands, e.g., 16, 18, 20, in wafer 12.

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 72% of the total text.

Page 1 of 2

Wafer Island Isolation Technique

An island 10 in a silicon wafer 12, indicated in Fig. 1, is tested before any circuits or lines 14, such as power or phase lines, from that island are connected to other islands, e.g., 16, 18, 20, in wafer 12.

As shown in Fig. 1, isolation field-effect transistors 22 are connected to lines 14 to selectively isolate island 10, which is to be tested, e.g., for shorts, from lines, including power and phase lines, which are common to other islands.

Transistors 22 are controlled by control circuit 24, provided on island 10, in accordance with the pulse program indicated in Fig. 2. Control circuit 24 includes transistors 26, 28 and 30, provided for selectively grounding the gate electrodes of isolation transistors 22, and a latch, which may be conventional, for selectively applying a control voltage to the gate electrode of transistor 30. A voltage doubler circuit is coupled to the gate electrodes of transistors 22 through diode- connected load transistor 32.

In operation, a reset pulse R is applied to the latch to turn off transistor 30. If, after reset pulse R has been applied, there is no X or Y pulse, island 10 is selected, the latch is preconditioned to accept an isolation control pulse, and transistors 26 and 28 are turned off, turning on transistors 22. Island 10 is then tested during the time indicated by the island cycle pulse.

If island 10 is found to be defective, an isolation control pulse is applied to the latch which turns...