Active solid-state devices (e.g. – transistors – solid-state diode – Combined with electrical contact or lead
Reexamination Certificate
1999-09-16
2002-07-23
Lee, Eddie (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Combined with electrical contact or lead
C257S737000, C257S741000, C257S743000, C257S762000, C257S765000, C257S766000, C257S508000, C438S411000, C438S687000, C438S688000
Reexamination Certificate
active
06424036
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device and a method for manufacturing the same and more particularly to a semiconductor device provided with a pad metal film to which a conductor for external connection to be connected to external wiring formed on a printed circuit board is fitted and wherein the pad metal film is covered, except a face for fitting the conductor for external connection, with a final protective insulating film.
2. Description of the Related Art
As the integration of an LSI (Large Scale Integrated Circuit) used for a microprocessor or memory, known as a typical semiconductor device increases, each region of such semiconductors constituting the LSI is being scaled down dimensionally. In wiring processes for each region of the semiconductor, an interconnection hole including a contact hole or via hole formed on an insulating film and a trench for interconnection into which wiring is imbedded are dimensionally scaled down as well. In response to higher wiring density, multi-level interconnect technology by which the wiring is multi-layered in the direction of a thickness of a semiconductor substrate is developing. In the updated LSI, a multi-level interconnect (for example, 5 to 7 levels) has been incorporated. In such LSIs, if used for a high-speed microprocessor in particular, a resistance value of wiring presents a problem in terms of operations. Wiring having less resistance is desired accordingly. Conventionally, as a material for wiring in semiconductor devices including LSIs, aluminum or aluminum metal composed mainly of aluminum being excellent in electric characteristics, processabilities and the like. However, aluminum metals have a shortcoming of being less resistant to electromigration and to stress migration. Because of this, there is a tendency that copper or copper metals composed mainly of copper, which is of less resistance compared with aluminum and is excellent in resistance against electromigration and stress migration, are used instead of aluminum.
FIG. 9
is a cross-sectional view showing a conventional semiconductor device (hereafter referred to as a first conventional example). In the conventional semiconductor substrate
65
in
FIG. 9
, a trench for interconnect
53
is formed in a protective insulating film
52
formed on a semiconductor substrate
51
and on the trench for interconnect is formed a uppermost-layered copper wiring
55
through a first barrier metal film
54
composed of a titanium nitride film or the like. The protective insulating film
52
is covered with a final protective insulating film
56
and in the final protective insulating film
56
is formed a contact hole
57
with an approximately central part of the uppermost-layered copper wiring
55
exposed. In this contact hole
57
is formed a second barrier metal film
58
composed of stacked layers containing, for example, a titanium nitride film, a nickel film and a gold film and through this second barrier metal film
58
is formed a copper pad metal film
59
. To this copper pad metal film
59
is fitted a bump-like conductor
60
composed of solder.
The first barrier metal film
54
is used to prevent adverse effects on the lower-layered wiring or diffused region caused by diffusion of the uppermost-layered copper wiring
55
into the protective insulating film
52
. Moreover, the second barrier metal film
58
is used to prevent the inconvenience of copper suctioning or the like caused by an action of solder components of the bump-like conductor
60
.
As shown in
FIG. 16
, a semiconductor device
65
is mounted, by a flip chip method (face-down bonding), on an external wiring
62
fitted to a printed circuit board
61
through a bump-like conductor
60
to be served as a conductor for external connection which is connected to the uppermost-layered copper wiring
55
.
Referring to
FIGS. 10A
,
10
B,
10
C,
11
A,
11
B,
11
A and
12
B, a method for manufacturing the first conventional example of the semiconductor device is described hereinafter in order of processes.
First, as shown in
FIG. 10A
, a trench for interconnect
53
is formed on a protective insulating film
52
mounted on a semiconductor substrate
51
by using lithography technology. Next, as shown in
FIG. 10B
, on the protection insulating film
52
containing the trench for interconnect
53
are sequentially formed the first barrier metal film
54
and uppermost-layered copper wiring film
55
A by using a sputtering method or the like.
Next, as shown in
FIG. 10C
, by removing both the first barrier metal film
54
and the uppermost-layered copper wiring film
55
from the upper face of both the protective insulating film
52
and the trench for interconnect
53
using a CMP (Chemical Mechanical Polishing) method, the protective insulating film
52
is planarized in order to form the uppermost-layered copper wiring
55
.
Next, as shown in
FIG. 11A
, after the formation of a final protective insulating film
56
on the protective insulating film
52
, a resist film
63
is formed. Then, as depicted in
FIG. 11B
, by using the resist film
63
as a mask, etching on the final protective insulating film
56
is performed to provide the contact hole
57
. Next, as shown in
FIG. 12A
, after the sequential formation of the second barrier metal film
58
and copper pad metal film
59
, a resist film
64
is formed. Furthermore, as shown in
FIG. 12B
, using the resist film
64
as a mask, patterning of the second barrier metal film
58
and the copper pad metal film
59
to a desired shape are performed. Then, by using a plating method, a bump-like conductor
60
composed of solder is fitted to the pad metal film
59
to produce a semiconductor device shown in FIG.
9
.
FIG. 13
is a cross-sectional view showing a conventional semiconductor device (hereinafter referred to as a second conventional example). As shown in
FIG. 13
, in a semiconductor device
70
, an aluminum pad metal film
66
is formed, through the second barrier metal film
58
, on the first barrier metal film
54
and uppermost-layered copper wiring
55
. To the aluminum pad metal film
66
is fitted a wire-like conductor
67
composed of aluminum. In this example, the second barrier metal film
58
serves to prevent a reaction between the uppermost-layered copper wiring
55
and the aluminum pad metal film
66
. The same reference numbers in
FIG. 13
designate corresponding parts shown in FIG.
9
and the description is omitted
The semiconductor device
70
, as shown in
FIG. 17
, is fixed, by face-up bonding, on a printed circuit board
61
using an adhesive agent and is then mounted on an external wiring
62
through a wire-like conductor
67
used as a conductor for external connection.
By referring to
FIGS. 14A
,
14
B,
15
A and
15
B, a method for manufacturing a second conventional example of semiconductor devices.
First, as shown in
FIG. 14A
, after the second barrier metal film
58
and the aluminum pad metal film
66
obtained in
FIG. 10C
are formed on a protective insulating film
52
, the first barrier metal film
54
and the uppermost-layered copper wiring
55
, a resist film
68
is formed. Next, as shown in
FIG. 14B
, using the resist film
68
as a mask, patterning of the second barrier metal film
58
and aluminum pad metal film
66
to a desired shape is performed.
Next, as depicted in
FIG. 15A
, after the formation of the final protective insulating film
56
on the protective insulating film
52
and aluminum pad metal film
66
, a resist film
69
is formed. Then, as shown in
FIG. 15B
, using the resist film
69
as a mask, patterning of the final protective insulating film
56
to a desired shape is performed to make the aluminum pad metal film
66
exposed. Then, by using a wire bonding method, a wire-like conductor
67
composed of aluminum is fitted to the aluminum pad metal film
66
to produce the semiconductor device shown in FIG.
9
.
In the conventional first and second examples of the semiconductor devices, there is a pro
Hutchins, Wheeler & Dittmar
Lee Eddie
Ortiz Edgardo
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