U.S. patent application number 12/051371 was filed with the patent office on 2008-10-02 for ag-based alloy wire for semiconductor package.
This patent application is currently assigned to MK ELECTRON CO. LTD.. Invention is credited to Jong Soo Cho, Jeong Tak Moon.
Application Number | 20080240975 12/051371 |
Document ID | / |
Family ID | 39794700 |
Filed Date | 2008-10-02 |
United States Patent
Application |
20080240975 |
Kind Code |
A1 |
Cho; Jong Soo ; et
al. |
October 2, 2008 |
AG-BASED ALLOY WIRE FOR SEMICONDUCTOR PACKAGE
Abstract
An Ag-based alloy wire for a semiconductor package is highly
reliable and can be fabricated with low costs. The Ag-based alloy
wire includes 0.05.about.5 wt % of at least one kind of a first
additive ingredient selected from the group consisting of platinum
(Pt), palladium (Pd), rhodium (Rh), osmium (Os), gold (Au), and
nickel (Ni), and Ag as a remainder.
Inventors: |
Cho; Jong Soo; (Seoul,
KR) ; Moon; Jeong Tak; (Suwon-city, KR) |
Correspondence
Address: |
VOLPE AND KOENIG, P.C.
UNITED PLAZA, SUITE 1600, 30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103
US
|
Assignee: |
MK ELECTRON CO. LTD.
Yongin-city
KR
|
Family ID: |
39794700 |
Appl. No.: |
12/051371 |
Filed: |
March 19, 2008 |
Current U.S.
Class: |
420/503 ;
420/501; 420/502; 420/505 |
Current CPC
Class: |
H01L 2224/45015
20130101; H01L 2224/45139 20130101; H01L 2224/45139 20130101; H01L
2224/45139 20130101; H01L 2224/45139 20130101; H01L 2224/45139
20130101; H01L 24/43 20130101; H01L 2224/45139 20130101; H01L
2224/45144 20130101; H01L 2224/45139 20130101; H01L 2224/45139
20130101; H01L 2224/45139 20130101; H01L 2224/45139 20130101; H01L
2224/48624 20130101; H01L 2224/45139 20130101; H01L 2224/45139
20130101; H01L 2924/00011 20130101; C22C 5/08 20130101; H01L
2224/45139 20130101; H01L 2224/45139 20130101; H01L 2224/45139
20130101; H01L 2224/45139 20130101; H01L 2224/45139 20130101; H01L
2224/45139 20130101; H01L 2224/45139 20130101; H01L 2224/45139
20130101; H01L 2924/01047 20130101; H01L 2224/45015 20130101; H01L
2224/45139 20130101; H01L 2224/45139 20130101; H01L 2224/45139
20130101; H01L 2224/45139 20130101; H01L 2224/45139 20130101; H01L
2224/48624 20130101; H01L 2924/0102 20130101; H01L 2924/01078
20130101; H01L 2924/00 20130101; H01L 2924/01022 20130101; H01L
2924/01022 20130101; H01L 2924/01028 20130101; H01L 2924/013
20130101; H01L 2224/45139 20130101; H01L 2224/45139 20130101; H01L
2224/05624 20130101; H01L 2224/45139 20130101; H01L 2224/43848
20130101; H01L 2224/45139 20130101; H01L 2224/45139 20130101; H01L
2224/45139 20130101; H01L 2224/45139 20130101; H01L 2924/013
20130101; H01L 2924/01039 20130101; H01L 2224/45139 20130101; H01L
2924/01046 20130101; H01L 2924/01078 20130101; H01L 2924/013
20130101; H01L 2924/00 20130101; H01L 2924/01029 20130101; H01L
2924/01046 20130101; H01L 2924/013 20130101; H01L 2924/013
20130101; H01L 2924/00014 20130101; H01L 2924/0102 20130101; H01L
2924/01028 20130101; H01L 2924/01004 20130101; H01L 2924/01014
20130101; H01L 2924/01029 20130101; H01L 2924/01049 20130101; H01L
2924/013 20130101; H01L 2924/01004 20130101; H01L 2924/01004
20130101; H01L 2924/01048 20130101; H01L 2924/01004 20130101; H01L
2924/01004 20130101; H01L 2924/01029 20130101; H01L 2924/013
20130101; H01L 2924/013 20130101; H01L 2924/013 20130101; H01L
2924/01014 20130101; H01L 2924/01046 20130101; H01L 2924/013
20130101; H01L 2924/013 20130101; H01L 2924/013 20130101; H01L
2924/013 20130101; H01L 2924/01045 20130101; H01L 2924/01046
20130101; H01L 2924/013 20130101; H01L 2924/00013 20130101; H01L
2924/01078 20130101; H01L 2924/01078 20130101; H01L 2924/013
20130101; H01L 2924/01058 20130101; H01L 2924/013 20130101; H01L
2924/013 20130101; H01L 2924/01057 20130101; H01L 2924/01029
20130101; H01L 2924/01046 20130101; H01L 2924/01056 20130101; H01L
2924/01076 20130101; H01L 2924/00 20130101; H01L 2924/00 20130101;
H01L 2924/01029 20130101; H01L 2924/01012 20130101; H01L 2924/01046
20130101; H01L 2924/01058 20130101; H01L 2924/01012 20130101; H01L
2924/01056 20130101; H01L 2924/013 20130101; H01L 2924/013
20130101; H01L 2924/013 20130101; H01L 2924/01046 20130101; H01L
2924/01076 20130101; H01L 2924/013 20130101; H01L 2924/01004
20130101; H01L 2924/01029 20130101; H01L 2924/013 20130101; H01L
2924/013 20130101; H01L 2924/01046 20130101; H01L 2924/01014
20130101; H01L 2924/01046 20130101; H01L 2924/01076 20130101; H01L
2924/013 20130101; H01L 2924/00015 20130101; H01L 2924/01029
20130101; H01L 2924/013 20130101; H01L 2924/013 20130101; H01L
2924/01057 20130101; H01L 2924/013 20130101; H01L 2924/01048
20130101; H01L 2924/013 20130101; H01L 2924/01039 20130101; H01L
2924/01058 20130101; H01L 2924/01079 20130101; H01L 2924/01045
20130101; H01L 2924/01045 20130101; H01L 2924/01048 20130101; H01L
2924/01078 20130101; H01L 2924/01079 20130101; H01L 2224/45139
20130101; H01L 2224/45139 20130101; H01L 2224/45139 20130101; H01L
2224/45139 20130101; H01L 2224/45139 20130101; H01L 2224/43848
20130101; C22C 5/06 20130101; H01L 24/45 20130101; H01L 2224/45139
20130101; H01L 2224/45139 20130101; H01L 2924/00011 20130101; H01L
2224/45139 20130101; H01L 2224/45139 20130101; H01L 2224/45139
20130101; H01L 2924/01047 20130101; H01L 2224/45139 20130101; H01L
2224/45139 20130101; H01L 2224/45144 20130101; H01L 2224/45139
20130101 |
Class at
Publication: |
420/503 ;
420/501; 420/502; 420/505 |
International
Class: |
C22C 5/06 20060101
C22C005/06; C22C 5/08 20060101 C22C005/08 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 2007 |
KR |
1020070031998 |
Claims
1. An Ag-based alloy wire for a semiconductor package, comprising
0.05.about.5 wt % of at least one kind of a first additive
ingredient selected from the group consisting of platinum (Pt),
palladium (Pd), rhodium (Rh), osmium (Os), gold (Au), and nickel
(Ni), and Ag as a remainder.
2. The Ag-based alloy wire of claim 1, wherein the first additive
ingredient comprises 0.05.about.5 wt % of palladium (Pd).
3. An Ag-based alloy wire for a semiconductor package comprising, 3
wtppm.about.5 wt % of at least one kind of a second additive
ingredient selected from the group consisting of copper (Cu),
beryllium (Be), calcium (Ca), magnesium (Mg), barium (Ba),
lanthanum (La), cerium (Ce), and yttrium (Y), and Ag as a
remainder.
4. The Ag-based alloy wire of claim 3, wherein the second additive
ingredient comprises 0.1.about.5 wt % of copper (Cu).
5. The Ag-based alloy wire of claim 3, wherein the second additive
ingredient comprises 3.about.100 wtppm of at least one selected
from the group consisting of beryllium (Be), calcium (Ca),
magnesium (Mg), barium (Ba), lanthanum (La), cerium (Ce), and
yttrium (Y).
6. An Ag-based alloy wire for a semiconductor package, comprising
0.05.about.5 wt % of at least one kind of a first additive
ingredient selected from the group consisting of platinum (Pt),
palladium (Pd), rhodium (Rh), osmium (Os), gold (Au), and nickel
(Ni), 3 wtppm.about.5 wt % of at least one kind of a second
additive ingredient selected from the group consisting of copper
(Cu), beryllium (Be), calcium (Ca), magnesium (Mg), barium (Ba),
lanthanum (La), cerium (Ce), and yttrium (Y), and Ag as a
remainder.
7. The Ag-based alloy wire of claim 6, wherein the second additive
ingredient comprises 0.1.about.5 wt % of copper (Cu) or 3.about.100
wtppm of at least one selected from the group consisting of
beryllium (Be), calcium (Ca), magnesium (Mg), barium (Ba),
lanthanum (La), cerium (Ce), and yttrium (Y).
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATION
[0001] This application claims the benefit of Korean Patent
Application No. 10-2007-0031998, filed on Mar. 30, 2007, in the
Korean Intellectual Property Office, the disclosure of which is
incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a semiconductor package,
and more particularly to a silver (Ag)-based alloy wire for wire
bonding.
[0004] 2. Description of the Related Art
[0005] In semiconductor packages, semiconductor chips can be
electrically connected to a package substrate using wire bonding.
In conventional semiconductor packages, an aluminum pad of a
semiconductor chip and a package substrate are bonded using gold
(Au) wires. Au has been widely used because of its high chemical
stability and high electrical conductivity. However, in order to
meet the continuous demand to decrease the manufacturing costs in
the semiconductor industry and address the cost increase of gold
price, a new wire that replaces the Au wire is required.
[0006] For example, Japanese Patent Application Laid-open Nos.
1998-326803, 1999-67811, 1999-67812, and 2000-150562 disclose
Au--Ag alloy wires. However, such Au--Ag alloy wires still include
Au at high composite rates, which limits the cost reduction.
[0007] An Ag wire that is cheap by 30 to 50% of the conventional Au
wire may be regarded as another example. However, the Ag wire has a
reliability problem when bonded to the aluminum (Al) pad.
Particularly as illustrated in FIG. 1, when performing a high
humidity reliability test, a bonding surface of the Ag wire and the
Al pad are most likely corroded or a chip crack occurs so that a
bonding strength is significantly decreased. The high humidity
reliability test is generally carried out using a pressure cooker
test (PCT). The bonding strength of the Au wire is scarcely changed
even after 96 hours in the PCT, but that of the Ag wire reaches
nearly zero even after 24 hours in the PCT.
[0008] Moreover, the Ag wire has a drawback of a poor plasticity,
which degrades product yield. Therefore, fabrication of the Ag
wires requires many heat annealing operations, which increases the
manufacturing costs.
SUMMARY OF THE INVENTION
[0009] The present invention provides an Ag-based alloy wire for a
semiconductor package, which is highly reliable and requires low
fabricating costs.
[0010] According to an aspect of the present invention, there is
provided an Ag-based alloy wire for a semiconductor package,
comprising 0.05.about.5 wt % of at least one kind of a first
additive ingredient selected from the group consisting of platinum
(Pt), palladium (Pd), rhodium (Rh), osmium (Os), gold (Au), and
nickel (Ni), and Ag as a remainder.
[0011] According to another aspect of the present invention, there
is provided an Ag-based alloy wire for a semiconductor package,
comprising 3 wtppm.about.5 wt % of at least one kind of a second
additive ingredient selected from the group consisting of copper
(Cu), beryllium (Be), calcium (Ca), magnesium (Mg), barium (Ba),
lanthanum (La), cerium (Ce), and yttrium (Y), and Ag as a
remainder.
[0012] According to another aspect of the present invention, there
is provided an Ag-based alloy wire for a semiconductor package,
comprising 0.05.about.5 wt % of the first additive ingredient, 3
wtppm.about.5 wt % of the second additive ingredient, and Ag as a
remainder.
[0013] The term wt % or wtppm refers to a ratio of weight of
ingredients to total weight of a wire in terms of % or ppm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above and other features and advantages of the present
invention will become more apparent by describing in detail
exemplary embodiments thereof with reference to the attached
drawings in which:
[0015] FIG. 1 is a graph illustrating the high humidity reliability
between an Au wire and an Ag wire in a pressure cooker test
(PCT).
DETAILED DESCRIPTION OF THE INVENTION
[0016] The present invention will now be described more fully with
reference to the accompanying drawings, in which exemplary
embodiments of the invention are shown. The invention may, however,
be embodied in many different forms and should not be construed as
being limited to the embodiments set forth herein; rather, these
embodiments are provided so that this disclosure will be thorough
and complete, and will fully convey the concept of the invention to
those skilled in the art.
[0017] A wire for a semiconductor package according to embodiments
of the present invention is used for bonding a semiconductor chip
to a package substrate. Thus, the wire for the semiconductor
package according to embodiments of the present invention may be
referred to as a bonding wire.
[0018] An Ag-based alloy wire according to embodiments of the
present invention may be formed by alloying a predetermined
quantity of additive ingredients into pure Ag. However, although
not specially mentioned, the Ag-based alloy wire possibly includes
unavoidable impurities in addition to Ag and the additive
ingredients. This is because, even pure Ag may include a minute
quantity of impurities when refining it, and a minute quantity of
impurities may be included to the Ag alloy when alloying it.
However, because the quantity of unavoidable impurities is
negligible and irregular as compared with the additive ingredients,
the unavoidable impurities are not generally observed. Therefore,
the scope of the present invention is not limited to whether
impurities are unavoidably included or not.
[0019] The Ag-based alloy wire according to an embodiment of the
present invention may include at least one kind of a first additive
ingredient selected from the group consisting of platinum (Pt),
palladium (Pd), rhodium (Rh), Osmium (Os), gold (Au), and nickel
(Ni), and the remainder may be Ag. For example, the Ag-based alloy
wire may be formed of the first additive ingredient in a content of
0.05.about.5 wt % and Ag as the remainder.
[0020] The first additive ingredient improves the high humidity
reliability of the Ag-based alloy wire. The first additive
ingredient can inhibit an oxide film formation and a galvanic
corrosion in the bonding surface between the Ag-based alloy wire
and a pad of a semiconductor chip. Thus, the occurrence of a chip
crack in the bonding surface can be prevented, and a bonding
strength can be improved.
[0021] However, if the amount of the first additive ingredient is
less than 0.05 wt %, the high humidity reliability of the
semiconductor package including the Ag-based alloy wire may be
insufficiently improved. For example, the chip crack may occur in
the bonding surface between the Ag-based alloy wire and the pad,
thereby decreasing the bonding strength between them. Furthermore,
if the amount of the first additive ingredient is greater than 5 wt
%, an electrical resistance of the Ag-based alloy wire is increased
and a free air ball of the Ag-based alloy wire is hardened in the
bonding surface, which might create a chip crack. Accordingly, the
reliability of the electrical connection of the wire and the
semiconductor chip can be greatly decreased.
[0022] The Ag-based alloy wire according to another embodiment of
the present invention may include at least one kind of a second
additive ingredient selected from the group consisting of copper
(Cu), beryllium (Be), calcium (Ca), magnesium (Mg), barium (Ba),
lanthanum (La), cerium (Ce) and yttrium (Y), and Ag as a
remainder.
[0023] For example, the second additive ingredient may include Cu
in the content of 0.1.about.5 wt %. As another example, the second
additive ingredient may include 3.about.100 wtppm of at least one
material selected from the group consisting of Be, Ca, Mg, Ba, La,
Ce, and Y. Alternatively, the second additive ingredient may
include Cu in the content of 0.1.about.5 wt %, and 3.about.100
wtppm of at least one material selected from the group consisting
of Be, Ca, Mg, Ba, La, Ce, and Y.
[0024] The second additive ingredient may contribute to further
improving the workability and the tensile strength rather than the
high humidity reliability of the Ag-based alloy wire. Therefore,
the number of heat annealing operations when fabricating the
Ag-based alloy wire can be greatly decreased as compared with the
conventional technique, which in turn greatly decreases the
fabricating costs.
[0025] If the content of Cu is less than 0.1 wt %, the improvement
of the workability may be negligible. Also, if the content of Cu is
greater than 5 wt %, the electrical resistance of the Ag-based
alloy wire is increased, and a chip crack occurs, which decreases
the bonding strength.
[0026] If the content of Be, Ca, Mg, Ba, La, Ce and Y is less than
3 wtppm, the improvement of the workability may be negligible.
Also, if the content of Be, Ca, Mg, Ba, La, Ce, and Y is greater
than 100 wtppm, solidified dimples are formed when the free air
balls are formed in the bonding surface so that the bonding
strength may be greatly decreased.
[0027] The Ag-based alloy wire according to another embodiment of
the present invention may include both the above-stated first
additive ingredient and the second additive ingredient, and the
remainder may be Ag. In this case, the high humidity reliability
and the workability of the Ag-based alloy wire can be improved.
[0028] Hereinafter, effects of the additive ingredients on the
characteristics of the Ag-based alloy wire will be described in
more detail with reference to exemplary embodiments and comparative
examples.
TABLE-US-00001 TABLE 1 First additive Second additive Others (wt
ingredient (wt %) ingredient (wtppm) ppm) Classification Ag Pd Pt
Rh Os Au Ni Cu Ca Be Mg Ba La Ce Y Cd Si Ti Exemplary 1 Bal. 0.01
Embodiment 2 Bal. 0.05 3 Bal. 0.1 4 Bal. 1 5 Bal. 5 6 Bal. 10 7
Bal. 30 8 Bal. 0.1 9 Bal. 1 10 Bal. 1 11 Bal. 1 12 Bal. 0.5 13 Bal.
0.01 14 Bal. 0.1 15 Bal. 1 16 Bal. 5 17 Bal. 0.05 18 Bal. 0.1 19
Bal. 1 20 Bal. 5 21 Bal. 10 22 Bal. 1 23 Bal. 3 24 Bal. 50 25 Bal.
100 26 Bal. 500 27 Bal. 10 28 Bal. 10 29 Bal. 10 30 Bal. 10 31 Bal.
10 32 Bal. 10 33 Bal. 0.1 0.1 34 Bal. 0.1 0.1 0.1 35 Bal. 0.1 0.1 5
36 Bal. 0.5 0.1 0.1 37 Bal. 0.5 10 10 38 Bal. 0.5 5 39 Bal. 0.5 5
40 Bal. 0.5 0.5 41 Bal. 0.5 0.5 5 Comparison 1 Bal. 10 2 Bal. 10 3
Bal. 10
TABLE-US-00002 TABLE 2 Bonding Strength (BPT) Tensile Before After
Strength Electrical Hardness Shelf Chip Classification PCT PCT
Reliability (g) Resistivity Workability (Hv) Life (day) Crack
Dimple Exemplary 1 10.5 1.5 X 14.3 1.7 1.51 63 32 None (X) None (X)
Embodiment 2 10.7 9.5 .circleincircle. 16.2 1.8 0.13 64 128 None
(X) None (X) 3 10.8 9.8 .circleincircle. 17.0 1.8 0.10 64 256 None
(X) None (X) 4 1 10.2 .circleincircle. 17.5 2.9 0.09 65 256 None
(X) None (X) 5 5 10.9 .circleincircle. 18.2 4.5 0.10 66 256 None
(X) None (X) 6 10 6.3 .largecircle. 21.6 10.8 1.56 70 256
Produced(O) None (X) 7 13.7 9.4 .largecircle. 25.8 35.7 5.8 93 256
Produced(O) None (X) 8 11.2 9.3 .circleincircle. 16.8 1.8 0.18 64
256 None (X) None (X) 9 11.4 9.4 .circleincircle. 17.5 2.7 0.17 64
256 None (X) None (X) 10 11.5 9.4 .circleincircle. 17.4 2.8 0.21 65
256 None (X) None (X) 11 11.6 9.3 .circleincircle. 17.7 2.9 0.31 64
256 None (X) None (X) 12 11.4 9.1 .circleincircle. 17.2 1.8 0.25 64
256 None (X) None (X) 13 9.5 2.1 X 14.5 1.7 0.25 64 32 None (X)
None (X) 14 11.3 9.5 .circleincircle. 17.2 1.8 0.25 64 256 None (X)
None (X) 15 12.3 9.6 .circleincircle. 18.0 2.8 0.30 64 256 None (X)
None (X) 16 12.5 9.6 .circleincircle. 18.5 4.7 1.32 66 256 None (X)
None (X) 17 10.5 1.5 X 14.3 1.7 1.68 63 32 None (X) None (X) 18
11.2 2.6 X 15.3 1.8 0.03 65 128 None (X) None (X) 19 11.3 2.6 X
15.5 2.7 0.03 66 128 None (X) None (X) 20 12.1 2.4 X 16.4 4.3 0.04
67 128 None (X) None (X) 21 12.8 2.6 X 17.7 10.5 0.06 74 128
Produced(O) None (X) 22 10.3 2.5 X 14.5 1.7 0.89 63 128 None (X)
None (X) 23 11.4 2.4 X 15.8 1.7 0.05 64 128 None (X) None (X) 24
12.6 2.1 X 17.8 1.7 0.04 65 128 None (X) None (X) 25 12.9 1.9 X
18.1 1.7 0.07 66 128 None (X) None (X) 26 12.9 1.5 X 18.2 1.8 1.74
71 128 Produced(O) Produced(O) 27 12.6 2.6 X 17.5 1.7 0.05 65 128
None (X) None (X) 28 12.6 2.4 X 17.4 1.7 0.06 65 128 None (X) None
(X) 29 12.4 2.8 X 17.2 1.7 0.05 65 128 None (X) None (X) 30 12.5
3.1 X 17.4 1.7 0.04 65 128 None (X) None (X) 31 12.4 2.8 X 17.2 1.7
0.05 64 128 None (X) None (X) 32 12.5 2.6 X 16.7 1.7 0.07 65 128
None (X) None (X) 33 11.6 9.4 .circleincircle. 16.9 1.8 0.09 64 256
None (X) None (X) 34 12.6 10.2 .circleincircle. 17.0 1.8 0.06 64
256 None (X) None (X) 35 12.8 10.0 .circleincircle. 17.5 1.8 0.05
65 256 None (X) None (X) 36 12.2 9.9 .circleincircle. 16.7 1.9 0.05
64 256 None (X) None (X) 37 12.7 10.2 .circleincircle. 17.4 1.9
0.06 65 256 None (X) None (X) 38 12.6 10.2 .circleincircle. 17.5
1.9 0.05 64 256 None (X) None (X) 39 12.8 10.3 .circleincircle.
17.8 1.9 0.03 64 256 None (X) None (X) 40 11.8 9.6 .circleincircle.
17.2 1.9 0.04 64 256 None (X) None (X) 41 12.5 10.1
.circleincircle. 18.2 1.9 0.03 64 256 None (X) None (X) Comparison
1 11.8 2.1 X 20.4 4.7 4.7 81 32 Produced(0) Produced(0) 2 12.6 1.8
X 20.8 3.8 3.8 83 32 Produced(0) Produced(0) 3 12.4 1.3 X 19.9 4.2
4.2 81 32 Produced(0) Produced(0)
[0029] Table 1 shows the Ag-based alloy wire according to the
contents of the additive ingredients. Experimental embodiments 1
through 16 show Ag-based alloy wires each of which contains one
kind of the first additive ingredient, and experimental embodiments
17 through 32 show Ag-based alloy wires each containing one kind of
the second additive ingredient. Experimental embodiments 33 through
41 show Ag-based alloy wires each of which contains either at least
two kinds of the first additive ingredient or at least two kinds of
the second additive ingredient, or each of which contains both the
first additive ingredient and the second additive ingredient.
Comparative examples 1 through 3 denoted the Ag-based alloy wires
each of which contains another additive ingredient exclusive of the
first additive ingredient and the second additive ingredient.
[0030] Table 2 shows the experimental result with respect to the
characteristics of the Ag-based alloy wires displayed in Table 1.
In Table 2, the high humidity reliability is indicated by a bonding
strength (BPT value) in the pressure cooker test (PCT). The
Ag-based alloy wire had a diameter of about 30 .mu.m, and the PCT
was carried out at a temperature of 121.degree. C. for about 96
hours. With regard to the reliability of the bonding strength,
.circleincircle. denotes a highly favourable state, .largecircle.
denotes a good state, .DELTA. denotes a normal state, and .times.
denotes a bad state. The workability was measured by the number of
disconnects per 1 km of the Ag-based alloy wire, and thus the
smaller number indicates better characteristics. The shelf life
test shows the daily hours elapsed for forming an oxide film to a
thickness of 100 nm on the Ag-based, and thus the greater number
indicates better characteristics.
[0031] Referring to Tables 1 and 2, the experimental embodiments 1
through 7 show the effects of the content of palladium (Pd), that
is, the first additive ingredient, on the characteristics of the
Ag-based alloy wire. In the experimental embodiments 2 through 5,
where the content of Pd was 0.05.about.5 wt %, the reliability of
the Ag-based alloy wire was excellent, and the workability was
better than that of the comparative examples 1 through 3. However,
in the experimental embodiment 1, where the content of Pd was 0.01
wt %, the bonding strength was poor and the shelf life period
decreased. Also, cracks occur in the experimental embodiments 6 and
7, where the content of Pd was respectively 10 and 30 wt %.
[0032] The experimental embodiments 8 through 16 shows the effects
of the content of one kind of the first additive ingredient
including Pt, Rh, Os, Au, and Ni on the characteristics of the
Ag-based alloy wire. In the experimental embodiments 8 through 12,
and 14 through 16, where the content of the first additive
component was 0.5.about.5 wt %, the reliability of the Ag-based
alloy wire was excellent, and the workability was better than that
of the comparative examples 1 through 3. Meantime, in the
experimental embodiment 13, where the content of Ni was 0.01 wt %,
the bonding strength was poor.
[0033] Consequently, it is concluded from the above experimental
results that the first additive ingredient including Pd, Pt, Rh,
Os, Au, and Ni similarly affects the characteristics of the
Ag-based alloy wire. Accordingly, the experimental results with
respect to Pd and Ni may be similarly applied to Pt, Rh, Os, and
Au.
[0034] The experimental embodiments 17 through 21 show the effects
of Cu, that is, the second additive ingredient, on the
characteristics of the Ag-based alloy wire. In the experimental
embodiments 18 through 20, where the content of Cu was 0.1.about.5
wt %, the workability was greatly improved over those of the
comparative examples 1 through 3 and, moreover, was slightly
improved over those of the experimental embodiments 1 through 16.
However, the experimental embodiment 17, where the content of Cu
was 0.05 wt %, showed a negligible improvement of the workability.
Also, the experimental embodiment 21, where the content of Cu was
10 wt %, showed an increase of the electrical resistivity and the
occurrence of chip cracks.
[0035] The experimental embodiments 22 through 26 show the effects
of Ca, that is, the second additive ingredient exerting on the
characteristics of the Ag-based alloy wire. In the experimental
embodiments 23 through 25, where the content of Ca was 3.about.100
wtppm, the workability that was greatly improved over those of the
comparative examples 1 through 3, moreover, was slightly improved
over those of the experimental embodiments 1 through 16. However,
the experimental embodiment 22, where the content of Ca was 1
wtppm, showed an increase of the electrical resistivity and the
occurrence of chip cracks. In the experimental embodiment 26, where
the content of Ca was 500 wt %, chip cracks occurred, and the
dimple was produced in the free air ball.
[0036] The experimental embodiments 27 through 32 show the effects
of the content of the second additive ingredient including Be, Mg,
Ba, La, Ce, and Y on the characteristics of the Ag-based alloy
wire. The experimental embodiments 27 through 32, where the content
of one of Be, Mg, Ba, La, Ce, and Y was 10 wt %, showed that
workability greatly improved over those of the comparative examples
1 through 3 and, moreover, was slightly improved over those of the
experimental embodiments 1 through 16.
[0037] Thus, from the above experimental result, it can be noted
that Be, Ca, Mg, Ba, La, Ce, and Y of the second additive
ingredient have similar characteristics. Accordingly, the
experimental result with respect to Ca may be similarly applied to
Be, Mg, Ba, La, Ce, and Y.
[0038] The experimental embodiments 33 through 41 show the effects
of at least two kinds of the first additive ingredient, at least
two kinds of the second additive ingredient, or mixing of the first
additive ingredient and the second additive ingredient on the
characteristics of the Ag-based alloy wire. The experimental
embodiments 33 through 41 satisfied the preferable content of each
of the first additive ingredient and the second additive ingredient
from the results of the experimental embodiments 1 through 32. In
this case, both the bonding strength and the workability were
further improved than those of the comparative examples 1 through
3. Therefore, both the first additive ingredient and the second
additive ingredient can be commonly included without adversely
affecting each other in the Ag-based alloy wire.
[0039] An Ag-based alloy wire according to the present invention
can increase an electrical conductivity while significantly
decreasing a unit cost as compared with a typically used Au
wire.
[0040] Also, the Ag-based alloy wire according to the present
invention has a bonding strength further increased over that of a
typically used Ag wire, thereby having increased reliability.
Moreover, the workability of the Ag-based alloy wire is increased,
which thereby decreases the fabricating costs of the Ag-based alloy
wire.
[0041] While the present invention has been particularly shown and
described with reference to exemplary embodiments thereof, it will
be understood by those of ordinary skill in the art that various
changes in form and details may be made therein without departing
from the spirit and scope of the present invention as defined by
the following claims.
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