Semiconductor device with multiple supporting points

Details Semiconductor device with multiple supporting points Semiconductor device with multiple supporting points

2001-04-02

2003-09-23

Wilson, Allen R. (Department: 2815)

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

Regenerative type switching device

With extended latchup current level

C257S177000, C257S180000, C257S725000, C257S732000, C361S760000, C361S770000, C361S801000

Reexamination Certificate

active

06624448

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device having a pressure-contact type semiconductor element, preferably being a gate commutated turn-off (hereinafter referred to as GCT) thyristor element, in which most of the main current flowing between the anode and cathode during turn-on can be commutated to the gate electrode at the time of turn-off, and particularly to improvement for enhancing the resistance to vibration.
2. Description of the Background Art
Conventional GTO (Gate Turn-Off) thyristor devices have widely adopted structures in which the gate terminal connected to the gate electrode is drawn out in one direction to transmit a control signal to the gate electrode (see the technique described in Japanese Patent Application Laid-Open No. 56-125863 (1981), for example). In such a structure, however, large inductance is parasitically generated at the gate terminal and it is therefore difficult to instantaneously terminate the main current flowing from the anode to cathode when the element is turned off.
GCT thyristor devices in which this inductance is remarkably lowered have been developed to solve this problem. Such a GCT thyristor device adopts a ring-shaped gate terminal in place of the gate terminal extending in one direction; such a ring-shaped gate terminal is connected to a gate drive substrate on which a gate driver is provided. (See the techniques described in Japanese Patent Application Laid-Open No. 10-294406 (1998) and Japanese Patent Application Laid-Open No. 8-330572 (1996), for example). GCT thyristor devices adopting this structure can reduce the inductance of the loop including the GCT thyristor element, gate drive substrate and gate driver (referred to as gate-side inductance) to about {fraction (1/100)} of that of GTO thyristors.
The GCT thyristor devices thus having much lower gate-side inductance than GTO thyristors can increase the reverse gate current rise rate (di
GQ
/dt) during turn-off to about 100 times that of GTO thyristors, thus commutating almost all main current to the gate in a short time to be turned off. That is to say, the time required for turning off can be reduced and the turn-off gain can be almost one, thus achieving improved turn-off characteristics. This suppresses breakdown due to local heat generation in the semiconductor substrate and enables control of large current.
FIG. 38
is a top view showing a semiconductor device which is regarded not as a known technique but as a background art of the invention. This semiconductor device
200
is described in an U.S. application (application Ser. No. 09/549,062) by the same applicant.
FIG. 39
shows the section of the semiconductor device taken along the line B—B in FIG.
38
. The semiconductor device
200
is constructed as a GCT thyristor device, which comprises a gate drive substrate
7
as a circuit board, a GCT thyristor
1
fixed on the gate drive substrate
7
and a gate driver as a control circuit including capacitors
36
and transistors
35
. The transistors
35
are attached to the wall surface of wall-like members
34
fixed vertically on the gate drive substrate
7
. While the capacitors
36
are arranged on the gate drive substrate
7
, they are not shown in
FIG. 39
for the sake of simplicity.
FIG. 40
shows the section of the semiconductor device taken along the line A—A in FIG.
38
and
FIGS. 41 and 42
are sectional views each showing a part of
FIG. 40
in an enlarged manner. The GCT thyristor element
1
comprises, in its center area, a disk-like semiconductor substrate (wafer)
24
having a pnpn structure inside and a gate region along the periphery, a cathode strain buffer plate
25
connected to the cathode region of the semiconductor substrate
24
, and an anode strain buffer plate
26
connected to the anode region of the semiconductor substrate
24
.
A cathode post electrode
2
as one main electrode is connected to the cathode strain buffer plate
25
and an anode post electrode
3
as the other main electrode is connected to the anode strain buffer plate
26
. Further, an electrically conductive first cathode flange (main terminal plate)
14
is connected to the cathode post electrode
2
and a cathode fin electrode
5
is connected to the first cathode flange
14
. An anode fin electrode
6
is connected to the anode post electrode
3
. The semiconductor substrate
24
, cathode strain buffer plate
25
, anode strain buffer plate
26
, cathode post electrode
2
, anode post electrode
3
and first cathode flange
14
are sandwiched and pressed between the cathode fin electrode
5
and the anode fin electrode
6
. Thus, the GCT thyristor element
1
is constructed as a kind of pressure-contact type semiconductor element.
In the semiconductor device
200
, the part excluding the cathode fin electrode
5
and the anode fin electrode
6
, i.e. the device part sandwiched with a pressing force between the pair of fin electrodes
5
and
6
, is called a gate drive unit
300
(hereinafter refereed to as GDU).
FIG. 38
shows the cathode fin electrode
5
with a broken line.
The GCT thyristor element
1
comprises a ring-shaped second cathode flange
20
fitted around the cathode post electrode
2
and a ring-shaped anode flange
23
fitted around the anode post electrode
3
. An insulating tube
21
made of ceramics (e.g. alumina) is provided between the second cathode flange
20
and the anode flange
23
. In
FIG. 40
, the unit composed of the semiconductor substrate
24
, cathode strain buffer plate
25
, anode strain buffer plate
26
, cathode post electrode
2
and anode post electrode
3
passes through the insulating tube
21
.
In the GCT thyristor element
1
, as shown in
FIGS. 41 and 42
, a cathode electrode
7
a
forming a path of current between the gate driver and the cathode of the GCT thyristor element
1
and a gate electrode
7
b
forming a path of current between the gate driver and the gate of the GCT thyristor element
1
are both formed on one main surface of the gate drive substrate
7
(the main surface to which the cathode fin electrode
5
faces is referred to as “upper main surface” hereinafter since this surface is shown as the upper surface in the drawings). The two are of course formed of circuit patterns insulated from each other. Although
FIG. 38
does not show these circuit patterns for the sake of simplicity, the cathode electrode
7
a
is formed in a circuit pattern which is connected to branch-like protrusions of the first cathode flange
14
which will be described later and the gate electrode
7
b
is formed in a circuit pattern which is connected to branch-like protrusions of the gate flange (control terminal plate)
15
described later. The presence of the cathode electrode
7
a
and the gate electrode
7
b
forms a loop between the gate and cathode of the GCT thyristor element
1
and the gate driver. The gate current flows into this loop during commutation, whereby the main current flowing between the cathode and anode of the GCT thyristor element
1
is instantaneously terminated.
FIG. 43
is a perspective view showing the structure of the first cathode flange
14
. The first cathode flange
14
is an electrically conductive thin plate having a thickness of about 0.2 to 2 mm, for example. As shown in
FIG. 43
, the first cathode flange
14
comprises a disk-like portion
14
f
having approximately the same diameter as the cathode post electrode
2
, a flange portion
14
e
surrounding the disk-like portion
14
f,
and a plurality of branch-like protrusions
14
d
extending approximately outward from the flange portion
14
e.
This structure can be obtained by processing a thin plate with a press machine etc. The one-piece structure as shown in
FIG. 43
, i.e. the branch-like protrusions
14
d ,
flange portion
14
e
and disk-like portion
14
f
integrally formed into the first cathode flange
14
, can be easily obtained through a single press process.
Each branch-like protrusion
14
d
has a screw hole
14
a
near its end. Screws
9
are inserted in the

Affiliated with

Also associated with

Rating

Semiconductor device with multiple supporting points does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Semiconductor device with multiple supporting points, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor device with multiple supporting points will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3012632