Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2000-10-20
2003-11-18
Chang, Richard (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S610100, C029S620000, C029S622000, C219S121600, C219S121680, C430S311000
Reexamination Certificate
active
06647614
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention provides a method and structure for changing the electrical resistance of a resistor.
2. Related Art
A resistor on a wafer may have its electrical resistance trimmed by using laser ablation to remove a portion of the resistor. For example, the laser ablation may cut slots in the resistor. With existing technology, however, trimming a resistor by using laser ablation requires the resistor to have dimensions on the order of tens of microns, which is large enough to be compatible with the laser spot dimension and laser alignment. A method is needed to trim a resistor having dimensions at a micron or sub-micron level.
SUMMARY OF THE INVENTION
The present invention provides a method for changing an electrical resistance of a resistor, comprising:
providing a resistor having a length L and a first electrical resistance R
1
; and
exposing a portion of the resistor to a laser radiation for a time of exposure, wherein the portion of the resistor includes a fraction F of the length L, wherein at an end of the time of exposure the resistor has a second electrical resistance R
2
, and wherein R
2
is unequal to R
1
.
The present invention provides an electrical structure, comprising:
a resistor having a length L and an electrical resistance R(t) at a time t; and
a laser radiation directed onto a portion of the resistor, wherein the portion of the resistor includes a fraction F of the length L, and wherein the laser radiation heats the portion of the resistor such that the electrical resistance R(t) instantaneously changes at a rate dR/dt.
The present invention provides an electrical resistor of length L, comprising N layers denoted as layers 1, 2, . . . , N:
wherein a portion of the resistor includes a fraction F of the length L;
wherein N is at least 2;
wherein layer I includes an electrically conductive material M
I
for I=1, 2, . . . , N;
wherein layer J is in electrically conductive contact with layer J+1 for J=1, 2, . . . , N−1; and
wherein a cell C
K,K+1
couples a cell C
K
′ of the layer K to a cell C
K+1
′ of the layer K+1, wherein the cell C
K
′ is within the portion of the resistor and includes the material M
K
, wherein the cell C
K+1
′ is within the portion of the resistor and includes the material M
+1
, wherein the cell C
K,K+1
is within the portion of the resistor and includes an electrically conductive material M
K,K+1
that comprises a chemical combination of the material M
K
from the layer K and the material M
K+1
from the layer K+1, and wherein K is selected from the group consisting of 1, 2, . . . , N−1, and combinations thereof.
The present invention provides an electrical resistor of length L, comprising:
a first portion having a length L
1
, wherein the first portion includes at least one cell having an electrically conductive material with a first structure; and
a second portion of length L
2
such that L
2
=L−L
1
, wherein the second portion includes a fraction F of the length L such that F=L
2
/L, wherein the second portion includes a structured cell having the electrically conductive material with a second structure, and wherein the electrically conductive material with the second structure has resulted from a laser heating of the electrically conductive material with the first structure.
The present invention provides a method for changing an electrical resistance of a resistor having dimensions at a micron or sub-micron level.
REFERENCES:
patent: 3996551 (1976-12-01), Croson
patent: 4714911 (1987-12-01), Di Mino et al.
patent: 4792779 (1988-12-01), Pond et al.
patent: 5468672 (1995-11-01), Rosvold
patent: 5656524 (1997-08-01), Eklund et al.
patent: 5685995 (1997-11-01), Sun et al.
patent: 5821160 (1998-10-01), Rodriguez et al.
patent: 5854116 (1998-12-01), Ohmi et al.
patent: 5907763 (1999-05-01), Stamper et al.
patent: 6461211 (2002-10-01), Raina et al.
patent: 6480092 (2002-11-01), Hoshii et al.
Ballantine Arne W.
Cabral, Jr. Cyril
Edelstein Daniel C.
Stamper Anthony K.
Chang Richard
International Business Machines - Corporation
Samodovitz Arthur J.
Schmeiser Olsen & Watts
LandOfFree
Method for changing an electrical resistance of a resistor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for changing an electrical resistance of a resistor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for changing an electrical resistance of a resistor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3162804