Active solid-state devices (e.g. – transistors – solid-state diode – Integrated circuit structure with electrically isolated... – Passive components in ics
Reexamination Certificate
2000-05-01
2003-09-30
Cao, Phat X. (Department: 2814)
Active solid-state devices (e.g., transistors, solid-state diode
Integrated circuit structure with electrically isolated...
Passive components in ics
C257S529000, C257S209000
Reexamination Certificate
active
06627969
ABSTRACT:
BACKGROUND INFORMATION
FIG. 1
(Prior Art) is a cross-sectional diagram of a conventional conductive plug-type antifuse
110
as disclosed in U.S. Pat. No. 5,308,795. A first conductor
114
is disposed on an insulating underlying layer
112
. First metal conductor
114
may comprise a sandwich structure of a lower barrier metal layer (for example, TiW), an aluminum layer (for example, AlSiCu), and an upper barrier layer (for example, TiW). Layer
116
is a layer of dielectric (for example, PECVD silicon dioxide). A conductive plug is disposed in an opening
118
in layer
116
and includes a conductive material
120
(for example, TiW) and a planarizing material
122
(for example, spin-on glass). Layer
124
is a layer of antifuse material (for example, a single layer of amorphous silicon). A capping layer
126
(for example, TiW or TiN) is provided on antifuse material layer
124
to prevent contamination of the antifuse layer from atoms in an overlying second metal conductor. Oxide spacers
128
are provided in order to minimize step coverage problems for the overlying second metal conductor
130
.
When unprogrammed, the first conductor
114
is not coupled to the second conductor
130
through the antifuse
110
. When programmed, however, antifuse
110
forms a permanent electrical connection between the first conductor
114
and the second conductor
130
.
It is desired to improve such an antifuse.
SUMMARY
A metal-to-metal conductive plug-type antifuse has a conductive plug disposed in an opening in an insulating layer. A layer of a programmable material (for example, amorphous silicon) overlies the conductive plug. A conductor involving a metal (for example, aluminum or copper) that migrates in the programmable material overlies the programmable material. The antifuse is programmed by forming a connection through the layer of programmable material such that the conductive plug is connected to the overlying conductor.
To prevent migration of metal from the conductor into the programmable material when the antifuse is not programmed, the conductor has a layer of barrier metal between the metal that migrates and the programmable material. In some embodiments, there are two layers of barrier metal. An airbreak after formation of the first barrier metal layer causes an improvement in the barrier properties of the first barrier metal layer. This airbreak may cause grain boundaries in the upper surface of the first barrier metal layer to be stuffed and/or may cause the upper barrier metal layer to be formed with different grains or a different grain orientation than the lower barrier metal layer. In some embodiments, a capping layer over the top surface of the programmable material protects the underlying programmable material during an ashing step when a mask used to etch the programmable material is removed. The capping layer and the programmable material form a capping layer/programmable material layer stack within the antifuse underneath the two barrier metal layers. The capping layer may also be made of a barrier metal and constitute an additional barrier.
This summary does not purport to define the invention. The invention is defined by the claims.
REFERENCES:
patent: 4823181 (1989-04-01), Mohsen et al.
patent: 4873459 (1989-10-01), El Gamal et al.
patent: 4876220 (1989-10-01), Mohsen et al.
patent: 4943538 (1990-07-01), Mohsen et al.
patent: 5055718 (1991-10-01), Galbraith et al.
patent: 5057451 (1991-10-01), McCollum
patent: 5070384 (1991-12-01), McCollum et al.
patent: 5087958 (1992-02-01), Chen et al.
patent: 5122685 (1992-06-01), Chan et al.
patent: 5130777 (1992-07-01), Galbraith et al.
patent: 5134457 (1992-07-01), Hamdy et al.
patent: 5163180 (1992-11-01), Eltoukhy et al.
patent: 5171715 (1992-12-01), Husher et al.
patent: 5196724 (1993-03-01), Gordon et al.
patent: 5233217 (1993-08-01), Dixit et al.
patent: 5308795 (1994-05-01), Hawley et al.
patent: 5362676 (1994-11-01), Gordon et al.
patent: 5373169 (1994-12-01), McCollum et al.
patent: 5387812 (1995-02-01), Forouhi et al.
patent: 5404029 (1995-04-01), Husher et al.
patent: 5411917 (1995-05-01), Forouhi et al.
patent: 5412244 (1995-05-01), Hamdy et al.
patent: 5424655 (1995-06-01), Chua
patent: 5449947 (1995-09-01), Chen et al.
patent: 5464790 (1995-11-01), Hawley
patent: 5486707 (1996-01-01), Look et al.
patent: 5495181 (1996-02-01), Kolze
patent: 5498895 (1996-03-01), Chen
patent: 5502315 (1996-03-01), Chua et al.
patent: 5510646 (1996-04-01), Forouhi et al.
patent: 5519248 (1996-05-01), Yan et al.
patent: 5557136 (1996-09-01), Gordon et al.
patent: 5592016 (1997-01-01), Go et al.
patent: 5619063 (1997-04-01), Chen et al.
patent: 5663091 (1997-09-01), Yen et al.
patent: 5670403 (1997-09-01), Chen
patent: 5701027 (1997-12-01), Gordon et al.
patent: 5753528 (1998-05-01), Forouhi et al.
patent: 5763299 (1998-06-01), McCollum et al.
patent: 5763898 (1998-06-01), Forouhi et al.
patent: 5920109 (1999-07-01), Hawley et al.
patent: 5970372 (1999-10-01), Hart et al.
patent: 6016001 (2000-01-01), Sanchez et al.
patent: 2086 654 (1982-05-01), None
S. Brown, et al., “Field Programmable Gate Arrays”, pp. 1-43 and 88-202 (1992).
Actel FPGA Data Book and Design Guide, pp. ii through 7-8 (1996).
QuickLogic Data Book 1996/97, pp. i through 6-36.
Actel 54SX Family FPGAs, pp. 1 through 35 (Mar. 1998).
Jain Rajiv
Shroff Mehul D.
Stolmeijer Andre
Cao Phat X.
Hulbert Michael J.
QuickLasic Corporation
Silicon Valley Patent & Group LLP
LandOfFree
Metal-to-metal antifuse having improved barrier layer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Metal-to-metal antifuse having improved barrier layer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Metal-to-metal antifuse having improved barrier layer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3006079