Method of manufacturing a semiconductor device with a pair of radiating terminals and a plurality of lead terminals formed from a single lead frame

A semiconductor device is disclosed wherein a pair of radiating terminals and a plurality of lead terminals are formed from a single lead frame. A hole or holes in each radiating terminal are formed with an equal width and in an equal pitch to those of gaps between the lead terminals, and the opposite sides of each hole of the radiating terminal are connected to each other by a support element. The support elements of the radiating terminals and support elements which interconnect the lead terminals are formed with an equal length and in an equal pitch to allow the support elements to be cut away by a plurality of punches which are arranged in an equal pitch and have an equal width.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a method of manufacturing a semiconductor device, 
and more particularly to a method of manufacturing a semiconductor device 
wherein a pair of radiating terminals and a plurality of lead terminals 
are formed from a single lead frame. 
2. Description of the Related Art 
Conventionally, semiconductor devices such as an LSI (Large Scale 
Integrated Circuit) and a transistor are utilized in various electronic 
apparatus. 
In such apparatus as just mentioned, a pellet comprising a semiconductor 
circuit is encapsulated in a resin member, and a plurality of lead 
terminals each formed from an elongated conductive plate are provided on 
the opposite sides of the resin member. Since those lead terminals are 
connected to connection pads of the pellet in the inside of the resin 
member, if the semiconductor device is mounted on a circuit board and the 
lead terminals are connected to signal lines, then various signals can be 
inputted to and outputted from the pellet. 
While such semiconductor devices are utilized in various applications,for 
example, a semiconductor device for use with a portable telephone set 
consumes a large amount of power, and consequently, a pellet of the 
semiconductor device generates a large amount of heat. Therefore, the 
generated heat of the pellet must be radiated efficiently. 
A conventional example of a semiconductor device which solves the subject 
just described is described below with reference to FIG. 1. 
In integrated circuit device 1 which is a semiconductor device shown as an 
example here, a pellet of an integrated circuit formed from a 
semiconductor circuit is mounted on a radiating plate in the form of an 
island (not shown), and a pair of radiating terminals 2 having a 
comparatively large width are provided on the opposite left and right 
sides of the radiating plate. 
A plurality of lead terminals 3 having a comparatively small width are 
arranged at positions forwardly and rearwardly of and adjacent to 
radiating terminals 2. Lead terminals 3 are connected to connection pads 
of the pellet by bonding wires (not shown). 
Since the pellet, the radiating plate, the bonding wires, inner portions of 
radiating terminals 2 and inner 25 portions of lead terminals 3 are 
encapsulated in resin member 4, outer portions 5 and 6 of terminals 2 and 
3 are provided projectingly on the left and right side faces of resin 
member 4. 
Outer portions 5 and 6 of terminals 2 and 3 are bent downwardly, and each 
of radiating terminals 2 has a hole 7 in the form of a slit formed at the 
bent portion thereof. 
When integrated circuit device 1 having such a construction as described 
above is to be mounted onto an upper surface of a circuit board, the 
plurality of-lead terminals 3 of integrated circuit device 1 are connected 
to a plurality of signal lines of the circuit board by solder, and the 
pair of radiating terminals 2 are connected to conductor patterns such as 
grounding lines of the circuit board. 
Thus, the pellet can input and output various information signals to and 
from the signal lines of the circuit board, and when the pellet generates 
heat, the heat is radiated from radiating terminals 2. 
A method of manufacturing integrated circuit device 1 having such a 
construction as described above is described briefly below with reference 
to FIGS. 2 and 3. 
First, leadframell is formed by etching a thin metal plate as seen in FIG. 
2. On this lead frame 11, a plurality of frame patterns 12 of integrated 
circuit devices 1 are arranged in rows and columns, and radiating plate 13 
is positioned at the center of one frame pattern 12. 
A pair of radiating terminals 2 having a comparatively large width are 
provided on the opposite left and right sides of radiating plate 13. A 
plurality of lead terminals 3 having a comparatively small width are 
arranged on the opposite front and rear sides, which are upper and lower 
sides in FIG. 2, of radiating terminals 2. 
Intermediate portions of terminals 2 and 3 are connected to each other by a 
plurality of tie bars 14. Outer end portions of terminals 2 and 3 are 
connected to outer frame portion 16 of frame pattern 12 by suspending pins 
15. 
Inner portions 17 of lead terminals 3 are formed such that they are 
directed radially toward the center of radiating plate 13. Inner portions 
18 of radiating terminals 2 are formed integrally with radiating plate 13. 
Holes 7 each in the form of a slit are formed at portions of outer portions 
5 of radiating terminals 2 at which radiating terminals 2 are to be bent 
later. 
A pellet comprising a semiconductor circuit is placed onto an upper face of 
radiating plate 13 of lead frame 11 formed in such a manner as described 
above, and a plurality of connection pads of the pellet and the plurality 
of lead terminals 3 are individually connected to each other with bonding 
wires (not shown). 
Lead frame 11 on which the pellet and the bonding wires are mounted 
integrally in this manner is placed into a cavity of a set of mutually 
removable metal molds such that it is held at outer portions 5 and 6 of 
radiating terminals 2 and 3 thereof by and between the metal molds, and in 
this state, molten resin is filled into the cavity of the metal molds and 
is then left so as to be solidified to form resin member 4. 
Then, as shown in FIG. 3, tie bars 14 and suspending pins 15 of lead frame 
11 which are exposed to the outside from resin member 4 are cut away by 
punches 19 to 21 so that outer portions 5 and 6 of radiating terminals 2 
and lead terminals 3 are separated from each other, and outer portions 5 
and 6 are bent downwardly, thereby completing integrated circuit device 1. 
When outer portions 5 and 6 of terminals 2 and 3 are bent in this manner, 
although radiating terminals 2 generally have a comparatively large width, 
since holes 7 are formed at the bent portions of radiating terminals 2, 
radiating terminals 2 can be bent readily similarly to lead terminals 3 
having a comparatively small width. 
However, since radiating terminals 2 and lead terminals 3 have different 
widths, punches 19 to 20 for cutting away tie bars 14 and suspending pins 
15 cannot be arranged in an equal pitch. 
Where punches 19 and 20 cannot be arranged in an equal pitch, operations 
for setting punches 19 and 20 to a press machine (not shown) are 
cumbersome, and also the universality of thus set punches 19 and 20 is 
low. 
Further, in order to cut away suspending pins 15 of lead terminals 3 having 
a comparatively small width and suspending pins 15 of radiating terminals 
2 having a comparatively large width, punches 20 having a comparatively 
small width and punches 21 having a comparatively large width are 
required. In other wards, since a plurality of kinds of punches 20 and 21 
having different widths are required, the productivity of integrated 
circuit device 1 is deteriorated thereby. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a method of 
manufacturing a semiconductor device which is high in productivity and a 
lead frame which contributes to improvement in productivity of a 
semiconductor device. 
In a conventional method of manufacturing a semiconductor device to which 
the present invention is applied, a lead frame is formed first. 
In the lead frame, a single radiating plate and a plurality of lead 
terminals of a comparatively small width are connected integrally to each 
other by tie bars and suspending pins. The single radiating plate has a 
pair of radiating terminals of a comparatively large width formed 
projectingly on the opposite sides thereof, and the plurality of lead 
terminals of a comparatively small width are arranged at positions 
adjacent to the radiating terminals. 
A pellet comprising a semiconductor circuit having a plurality of 
connection pads provided on an upper surface thereof is placed onto an 
upper surface of the radiating plate of the lead frame formed in such a 
configuration as described above. The plurality of connection pads of the 
pellet and the plurality of lead terminals of the lead frame are connected 
individually to each other with bonding wires. 
The lead frame on which the pellet and the bonding wires are mounted 
integrally is placed into a cavity of a set of mutually removable metal 
molds, and the metal molds are closed integrally such that outer portions 
of the radiating terminals and the lead terminals are held by the metal 
molds. 
Molten resin is filled into the cavity of the metal molds. The filled resin 
is left so as to be solidified to form a resin member in which the pellet, 
the radiating plate, the bonding wires, inner portions of the radiating 
terminals and inner portions of the lead terminals are encapsulated. 
The tie bars and the suspending pins of the lead frame exposed to the 
outside from the resin member are cut away to separate the outer portions 
of the radiating terminals and the lead terminals individually from each 
other. The outer portions of the lead terminals and the lead terminals 
extending outwardly from the resin member are bent downwardly. 
According to the present invention in such a method of manufacturing a 
semiconductor device as described above, when the lead frame is formed, 
the radiating terminals and the plurality of lead terminals are, connected 
to each other at portions thereof to be bent later at the tie bars and at 
least one hole which has an equal inner width and an equal arrangement 
pitch as those of gaps between the plurality of lead terminals and whose 
opposite sides are connected to each other by one of the tie bars is 
formed at the portion of each of the radiating terminals that is to be 
bent. 
When the tie bars of the lead frame exposed to the outside from the resin 
member are cut away, the plurality of tie bars positioned at the gaps 
between the lead terminals and the holes of the radiating terminals are 
cut away with an equal width and at an equal pitch. 
Then, when the outer portions of the radiating terminals and the plurality 
of lead terminals are bent, the radiating terminals are bent at the 
positions of the holes. 
Accordingly, with the method of manufacturing a semiconductor device of the 
present invention, the holes are formed in the radiating terminals having 
a comparatively large width of lead frame at the portion to be bent, and 
the opposite sides of each of the holes are connected to each other by one 
of the tie bars. Since the radiating terminals and the plurality of lead 
terminals are connected to each other by the tie bars and the plurality of 
tie bars having an equal inner width and an equal arrangement pitch to 
those of the tie bars, the tie bars are cut away by a plurality of punches 
arranged in an equal pitch and having an equal width. 
Since the plurality of punches for cutting away the plurality of tie bars 
can be formed with an equal width and can be arranged at an equal pitch, 
operations for setting the punches in position into a press machine are 
simple, and also the universality of the punches thus set is good. 
It is to be noted that, in the present invention, the direction in which 
the pellet is mounted with respect to the radiating plate is referred to 
as upward direction while a direction perpendicular to the direction is 
referred to as sideward direction. However, such directions are used 
conveniently in order to simplify description and do not restrict any 
direction when the device is manufactured or used actually. 
Further, the radiating plate in the present invention signifies a member on 
which a pellet is mounted and which contributes to radiation of heat from 
the pellet, and allows an island made of a metal. 
In the method of manufacturing a semiconductor device of the present 
invention, when the lead frame is formed, outer end portions of the 
radiating terminals and the plurality of lead terminals may be connected 
to an outer frame portion of the lead frame by a plurality of suspending 
pins having an equal inner width and an equal arrangement pitch, and, when 
the tie bars and the suspending pins of the lead frame exposed to the 
outside from the resin member are cut away, the plurality of suspending 
pins which interconnect the outer end portions of the radiating terminals 
and the plurality of lead terminals and the outer frame portion may be cut 
away with equal width and in equal pitch. 
In this instance, since radiating terminals having a comparatively large 
width and the lead terminals of a comparatively small width of lead frame 
are connected to the outer frame portion of the lead frame by a plurality 
of suspending pins having an equal inner width and an equal arrangement 
pitch, the suspending pins are cut away by a plurality of punches arranged 
in an equal pitch and having an equal width. 
Since the plurality of punches for cutting away the plurality of suspending 
pins can be formed with an equal width and can be arranged in an equal 
pitch, operations for setting the punches in position into a press machine 
are simple and also the universality of the punches thus set is good. 
A conventional lead frame to which the present invention is applied 
includes a substantially rectangular radiating plate, a pair of radiating 
terminals of a comparatively large width provided projectingly on the 
opposite sides of the radiating plate, a plurality of lead terminals of a 
comparatively small width arranged at positions adjacent to the radiating 
terminals, an outer frame portion positioned on the outer side of outer 
end portions of the radiating terminals and the plurality of lead 
terminals, a plurality of suspending pins for connecting the outer end 
portions of the radiating terminals and the plurality of lead terminals 
individually to the outer frame portion, and a plurality of tie bars for 
interconnecting intermediate portions of the radiating terminals and the 
plurality of lead terminals. 
In the present invention in such a lead frame as described above, 
each of the radiating terminals has at least one hole formed therein such 
that the hole has an equal width and an equal arrangement pitch as those 
of gaps between the plurality of lead terminals and the opposite sides of 
the hole are connected to each other by one of the tie bars, and the 
plurality of tie bars which interconnect the intermediate portions of the 
radiating terminals and the plurality of lead terminals have an equal 
overall length and an equal arrangement pitch to those of the tie bars of 
the holes of the radiating terminals. 
Accordingly, with the lead frame of the present invention, the holes are 
formed in the radiating terminals having a comparatively large width at 
the portions to be bent of, and the opposite sides of each of the holes 
are connected to each other by one of the tie bars. Since the radiating 
terminals and the plurality of lead terminals are connected to each other 
by the tie bars and the plurality of tie bars having an equal inner width 
and an equal arrangement pitch to those of the tie bars, the tie bars are 
cut away by a plurality of punches arranged in an equal pitch and having 
an equal width. 
Since the plurality of punches for cutting away the plurality of tie bars 
can be formed with an equal width and can be arranged at an equal pitch, 
operations for setting the punches in position into a press machine are 
simple, and also the universality of the punches thus set is good. 
The lead frame of the present invention may be constructed such that the 
outer end portions of the radiating terminals and the plurality of lead 
terminals are connected to the outer frame portion of the lead frame by a 
plurality of suspending pins which have an equal inner width and an equal 
arrangement pitch. 
In this instance, since radiating terminals having a comparatively large 
width and the lead terminals of a comparatively small width of lead frame 
are connected to the outer frame portion of the lead frame by a plurality 
of suspending pins having an equal inner width and an equal arrangement 
pitch, the suspending pins are cut away by a plurality of punches arranged 
in an equal pitch and having an equal width. 
Since the plurality of punches for cutting away the plurality of suspending 
pins can be formed with an equal width and can be arranged in an equal 
pitch, operations for setting the punches in position into a press machine 
are simple and also the universality of the punches thus set is good. 
The above and other objects, features and advantages of the present 
invention will become apparent from the following description with 
reference to the accompanying drawings which illustrate examples of the 
present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
An embodiment of the present invention is described with reference to FIGS. 
4 to 7. It is to be noted that those elements of the present embodiment 
which are common to those of the conventional example described 
hereinabove are denoted by same terms and detailed description of them is 
omitted here. 
First, also in integrated circuit device 31 which is a semiconductor device 
of the present embodiment, a pair of radiating terminals 32 having a 
comparatively large width are provided projectingly on the opposite left 
and right sides of a radiating plate on which a pellet is mounted as shown 
in FIG. 7 similarly as in integrated circuit device 1 described 
hereinabove. 
A plurality of lead terminals 33 having a comparatively small width are 
disposed at positions forwardly and rearwardly of and adjacent to 
radiating terminals 32, and outer portions 35 and 36 of terminals 32 and 
33 provided in and projecting from resin member 34 are bent downwardly. 
However, in integrated circuit device 31 of the present embodiment, 
different from integrated circuit device 1 described hereinabove, two 
holes 37 having a comparatively small width are formed at a bent portion 
of each of radiating terminals 32. Holes 37 of radiating terminals 32 have 
an inner width equal to that of the gaps between the plurality of lead 
terminals 33 and have an arrangement pitch equal to that of the gaps. 
Also when integrated circuit device 31 of the present embodiment having 
such a construction as described above is mounted onto an upper surface of 
a circuit board, the plurality of lead terminals 33 of integrated circuit 
device 31 are connected to a plurality of signal lines of the circuit 
board by solder and the pair of radiating terminals 32 are connected to 
conductor patterns such as grounding lines or like lines of the circuit 
board. 
Consequently, the pellet can input and output various information signals 
to and from the signal lines of the circuit board, and heat generated by 
the pellet can be radiated from radiating terminals 32. 
Here, a method of manufacturing such integrated circuit device 31 as 
described above is described briefly below with reference to the drawings. 
First, lead frame 41 is formed by etching a thin metal plate as seen in 
FIG. 4. 
Also with this lead frame 41, a plurality of frame patterns 42 of 
integrated circuit devices 31 are provided in rows and columns, and 
radiating plate 43 is positioned at the center of each one frame pattern 
42. 
A pair of radiating terminals 32 having a comparatively large width are 
provided projectingly on the opposite left and right sides of radiating 
plate 43. A plurality of lead terminals 33 having a comparatively small 
width are arranged on the opposite front and rear sides of radiating 
terminals 32, which are upper and lower sides in FIG. 4. 
Portions of terminals 32 and 33 to be bent are connected to each other by a 
plurality of tie bars 44. Outer end portions of terminals 32 and 33 are 
connected to outer frame portion 46 of frame pattern 42 by suspending pins 
45. 
Inner portions 47 of lead terminals 33 are formed such that they are 
directed radially toward the center of radiating plate 43. Inner portions 
48 of radiating terminals 32 are formed integrally with radiating plate 43 
. 
Two holes 37 are formed at a portion of outer portion 35 of each of 
radiating terminals 32 at which radiating terminal 32 is to be bent. 
However, since the opposite front and rear sides of each of holes 37 which 
are the upper and lower sides in FIG. 4 are connected by one of tie bars 
44, the two holes 37 at present point of time are formed as four holes. 
Since holes 37 of radiating terminals 32 have an equal inner width and have 
an equal arrangement pitch as those of the gaps between the plurality of 
lead terminals 33 as described above, those tie bars 44 which interconnect 
the opposite sides of holes 37 have an equal overall length and an equal 
arrangement pitch as those of tie bars 44 which interconnect terminals 32 
and 33. 
Further, while the plurality of lead terminals 33 having a comparatively 
small width are individually connected to outer frame portion 46 of frame 
pattern 42 by a plurality of suspending pins 45 having a comparatively 
small width, each of radiating terminals 32 having a comparatively large 
width is connected to three suspending pins 45 having a comparatively 
small width. Those suspending pins 45 have an equal inner width and have 
an equal arrangement pitch. 
A pellet comprising a semiconductor circuit is placed onto an upper surface 
of radiating plate 43 of lead frame 41 formed in such a manner as 
described above, and a plurality of connection pads of the pellet and the 
plurality of lead terminals 33 are individually connected to each other 
with bonding wires (not shown). 
Lead frame 41 on which the pellet and the boarding wires are mounted 
integrally in this manner is placed into a cavity of a set of mutually 
removable metal molds such that it is held at outer portions 35 and 36 of 
terminals 32 and 33 by the between the metal molds, and in this condition, 
molten resin is filled into the cavity of the metal molds and is then left 
so as to be solidified to form resin member 34. 
Then, as seen in FIGS. 5 and 6, tie bars 44 and suspending pins 45 of lead 
frame 41 which are exposed outwardly from resin member 34 are cut away and 
outer portions 35 and 36 of terminals 32 and 33 are separated from each 
other. Then, outer portions 35 and 36 are bent downwardly as seen in FIG. 
7, thereby completing integrated circuit device 31. 
With integrated circuit device 31 of the present embodiment, when outer 
portions 35 and 36 of terminals 32 and 33 are bent, although radiating 
terminals 32 have a generally large width, since they have holes 37 at 
portions to be bent thereof, they can be bent readily similarly to lead 
terminals 33 having a comparatively small width. 
Besides, even if radiating terminals 32 and lead terminals 33 have 
different widths from each other, since tie bars 44 and suspending pins 45 
have an equal width and are arranged in an equal pitch, punches 51 and 52 
for cutting away them can be arranged in an equal pitch. 
Consequently, an operation of setting punches 51 and 52 in position into a 
press machine (not shown) is simple, and also the universality of punches 
51 and 52 thus set is high. 
Further, lead terminals 33 having a comparatively small width and radiating 
terminals 32 having a comparatively large width are connected to outer 
frame portion 46 of lead frame 41 by suspending pins 45 having an equal 
comparatively small width. Accordingly, for punches 52 for cutting away 
suspending pins 45, a single kind of punches can be used, and integrated 
circuit device 31 can be manufactured in a high productivity. 
While preferred embodiments of the present invention have been described 
using specific terms, such description is for illustrative purposes only, 
and it is to be understood that changes and variations may be made without 
departing from the spirit or scope of the following claims.