Electronic component with an insulating coating

Details Electronic component with an insulating coating Electronic component with an insulating coating

1999-02-12

2001-07-31

Clark, Sheila V. (Department: 2815)

Active solid-state devices (e.g., transistors, solid-state diode

Lead frame

With structure for mounting semiconductor chip to lead frame

C257S666000, C257S783000

Reexamination Certificate

active

06268647

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electronic component manufactured using the anode junction and method of manufacturing the electronic component, and more particularly to an electrical contact between outgoing wiring and an electrode portion made with an insulating layer surrounding each electrode portion on a semiconductor chip surface, an electric conductor surface of each outgoing wiring being anodically bonded with each other when the outgoing wiring is simultaneously pressure-joined and connected to electrode portions on the semiconductor chip surface.
2. Description of the Related Art
FIG. 39
is a perspective view showing a sate in which electrodes
2
attached to a surface of a semiconductor chip
1
according to a conventional ultrasonic thermocompression wire bonding method are connected through gold lines
5
to inner leads
4
extending from lead frames, not shown, and
FIG. 40
is a diagrammatic illustration of a state in which one end of the gold line is being connected to the electrode
2
on the semiconductor chip
1
by ultrasonic thermocompression bonding.
In
FIG. 40
, the semiconductor chip
1
is fixedly secured through a die bonding material
6
to a die pad
41
. The die bonding material
6
and the die pad
41
can withstand the pressing force form a capillary
7
needed to form a ball
51
at the tip portion of the gold line
5
into a ball bonding configuration
52
when being connected to the electrode
2
by ultrasonic thermocompression bonding, and further support the semiconductor chip
1
. In the ultrasonic thermocompression wire bonding method, the tip portion of the gold line
5
passing through the capillary
7
is turned into the ball
51
configuration by means of a high-voltage discharge. Subsequently, the ball
51
is pressed against the electrode
2
on the semiconductor chip
1
and subjected to ultrasonic vibration and heat, whereby it is ultrasonically thermocompression-bonded to the electrode
2
as indicated at
52
in the same illustration. Further, the capillary
7
is moved to the position of the tip portion of the inner lead
4
before being lowered to couple the tip portion of the inner lead
4
to the gold line
5
.
FIGS. 41A
,
41
B and
42
are illustrations of a structure of a lead frame in a state where the electrodes
2
are coupled through the gold lines
5
to the tip portions of the inner leads
4
in accordance with a conventional ultrasonic thermocompression wire bonding method. In
FIG. 41A
, a frame
3
is formed integrally with 8 die pads
41
, not shown, and 36 inner leads
4
, not shown.
FIG. 41B
is an enlarged view showing a portion indicated by X in FIG.
41
A. In
FIG. 41B
, the frame
3
has 36 inner leads
4
at its inside portion, a die pad
41
supported by the frame
3
through suspended leads
42
at its central portion, and external leads
44
at its circumferential portion.
FIG. 42
is an illustration of the detailed structure of the 36 inner leads
4
, die pad
41
and suspended leads
42
. In the same illustration, a rectangle indicated by a broken line is representative of a position that is packed with a molding resin.
FIG. 43
is a cross-sectional view showing a semiconductor device completed such that the electrode
2
is connected through the gold line
5
to the inner lead
4
in accordance with the foregoing ultrasonic thermocompression wire bonding method before the frame
3
is packed with a molding resin
8
. In the same illustration, reference numeral
53
designates a contact portion between the inner lead
4
and the gold line
5
due to the ultrasonic thermocompression bonding.
FIG. 44
is an enlarged view showing a pressure-bonded portion between an electrode, not shown, and the inner lead
4
on the chip
1
, and
FIG. 45
is an illustration of the deformation of the ball
51
when the ball
51
is ultrasonically thermocompression-bonded onto the electrode
2
on a surface of the semiconductor chip
1
. In the same illustration, when the electrode
2
is an aluminium electrode, the gold line
5
and the ball-deformed portion
52
both consist of the same gold line material at the time of the completion of the ultrasonic thermocompression bonding, while an alloy layer of gold and aluminium is formed as a pressure-bonded layer
54
with the aluminium electrode. Reference numeral
2
i
depicts an electrically insulating passivation film (which will be referred hereinafter to as an electrically insulating film) attached on the semiconductor chip
1
at a position other than the electrode
2
.
FIG. 46
illustrates a state in which the ball-deformed portion
52
of the gold line
5
is pressed against the electrode
2
by means of the capillary
7
with the completed connection.
FIG. 47
shows a state in which the other end portion of the gold line
5
is stitch-bonded to the inner lead
4
by the capillary
7
and its deformed portion
53
is pressed against the tip portion of the inner lead
4
. In
FIG. 47
, although the material of the deformed portion
53
stitch-bonded to the inner lead
4
depends upon the lead frame material, when an iron frame is used, a silver plating is made, and hence an alloy layer made of gold and silver is produced in the stitch side. For this reason, the alloy layer
54
made of gold is present as shown in
FIG. 45
, but has been omitted in FIG.
47
.
FIGS. 48A
to
48
E are illustrations for describing processes taken when the inner lead
4
is connected through the gold line
5
to an electrode on the semiconductor chip
1
according to the conventional ultrasonic thermocompression wire bonding technique. In
FIG. 48A
, heat is transferred from a heating block
9
through the die pad
41
to the chip
1
by heat conduction. The tip portion of the gold line
5
leading from the tip portion of the capillary
7
is formed into a ball configuration by a high voltage power supply torch
10
to have a ball configuration.
FIG. 48B
shows a state in which the capillary
7
is lowered toward the electrode
2
(omitted from the illustration) so that formed ball
51
is pressure-bonded to the electrode under the ultrasonic vibration and pressing force.
FIG. 48C
illustrates a state in which the capillary
7
through which the gold line
5
passes is moved toward the inner lead
4
in order for the other end of the gold line
5
to be connected to the inner lead
4
after the ultrasonic thermocompression bonding of the ball
51
is completed as shown in FIG.
45
.
FIG. 48D
is illustrative of a state where the other end of the gold line
5
is stitch-bonded to the inner lead
4
, and
FIG. 48E
is illustrative of a state in which the other end of the gold line
5
is pressure-attached to the inner lead
4
by the stitch bonding in the state as shown in
FIG. 47
before the gold line
5
is held and lifted by a clamp
11
of the capillary
7
to be cut off at the stitch bonded portion.
FIG. 49
is a top plan view of a semiconductor chip
1
produced such that the electrode
2
and the inner lead
4
are coupled through the gold line
5
to each other by means of the ultrasonic thermocompression bonding, and
FIG. 50
illustrates 19 electrodes
2
on the semiconductor chip
1
, wherein reference numeral
2
i
designates an electrically insulating film attached to a portion other than the electrodes
2
on the semiconductor chip
1
. The electrode
2
has a dimension of C×E and the electrically insulating film
2
i
has a dimension B×D larger than the dimension of the electrode
2
, and hence the boundary between the electrode
2
and the electrically insulating film
2
i
appears so that the electrode
2
is exposed as shown in FIG.
51
. The cross-sectional structure of the semiconductor chip
1
is made such that the electrically insulating film
2
i
overlaps with the circumferential portion of the electrode
2
as shown in FIG.
45
. As illustrated in
FIG. 51
, in order to increase the electrical and mechanical degree of coupling of the gold line
5
, the area of the electrode
2
should

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