Semiconductor device and process for producing the same, and tape carrier used in said process

According to the present invention, a tape carrier is prepared which comprises a power trunk line including an electric connection as a branch of a power lead for each tape carrier unit and a ground trunk line having an electric connection as a branch of a ground lead for each tape carrier unit, the power and trunk lines being continuously formed along the longitudinal direction of the tape carrier, and a lead for a control signal for establishing an electric conduction along the longitudinal direction of the tape carrier via an aging wiring for semiconductor pellets to conduct a simultaneous multipoint (gang) bonding on the tape carrier. By mounting the semiconductor pellets having the aging wiring on the tape carrier, it is enabled to apply the power voltage and to supply the control signal to each of the plurality of the semiconductor pellets, and hence the operation test can be simultaneously conducted for the semiconductor pellets mounted on the tape carrier having an arbitrary length. This provision enables a plurality of semiconductor devices mounted on the tape carrier to be subjected to an aging, namely, a reliability test under a thermal environment and in the operating state, and hence an efficient reliability test can be achieved with an effect of the mass production. Consequently, a highly reliable semiconductor device can be provided.

BACKGROUND OF THE INVENTION 
The present invention relates to a semiconductor device and a process for 
producing the same, and a tape carrier used in the process. 
Among the semiconductors, there are semiconductors produced according to a 
so-called tape carrier system. Such a semiconductor device is produced by 
use of a tape carrier with techniques such as a wire bonding, the tape 
carrier having a plurality of leads (wiring pattern) with a predetermined 
shape formed thereon by use of, for example, a copper foil. The tape 
carrier is made of a tape (film) manufactured by use of an insulating 
material such as polyimide. Namely, an electrode of a semiconductor pellet 
in which an integrated circuit (IC) or a large-scale integrated circuit 
(LSI) is formed is bonded to an end of the lead by use of a simultaneous, 
multipoint bonding, namely, by the gang bonding, and thereafter the other 
end of the lead is cut off and is linked to a wiring electrode of a wiring 
board such as a printed circuit board, thereby manufacturing the 
semiconductor device. 
The tape carrier is of a long size including a plurality of tape carrier 
units each formed by locating a lead pattern corresponding to an external 
lead of a semiconductor pellet on a tape manufactured by use of an 
insulation material. With the semiconductor pellet being bonded to the 
tape carrier unit, the tape carrier can be wound up on a reel for storage. 
As a consequence, the tape carrier system is a technology quite suitable 
for automation of the production of semiconductors, for example, watches 
and calculators, namely, so-called chip-on-board type semiconductor 
devices. 
Incidentally, the tape carrier system is described in "IC JISSO GIJUTSU (IC 
PLACEMENT TECHNOLOGY)", Japan Electronics Association; K.K. Kogyo Chosa 
Kai, Jan. 14, 1980 (Page 107 and subsequent pages). 
SUMMARY OF THE INVENTION 
For the recent semiconductor devices, the higher reliability is required. 
To this end, the aging is achieved as a reliability test in which a 
semiconductor device is subjected to an electrical operation state under a 
thermal environment of the state where the device is heated. 
However, the tape carrier system is attended with a difficulty that the 
aging of a semiconductor device cannot be easily accomplished. The 
inventor of the present invention has found that the problem is 
particularly considerable for a semiconductor which does not operate 
unless the power supply voltage associated with the electrical operation 
test is applied and the control signal is further supplied thereto. 
The problem will be described in detail herebelow. 
In a semiconductor device produced according to the tape carrier system, 
the lead thereof is formed with a copper foil having a thickness of about 
35 .mu.m and is hence soft and easy to deform. Consequently, the handling 
of the lead for each semiconductor is difficult, namely, cannot be easily 
effected. This is because such a semiconductor device produced according 
to the tape carrier system is compact; and hence a great difficulty 
appears when manually transporting the device or when mounting the device 
in a tester for the device test. As described above, therefore, also in 
the aging test, the handling of the compact semiconductor device having 
the leads produced in the tape carrier system is accompanied by a 
considerable difficulty. Moreover, it is practically almost impossible in 
some cases to attach a terminal for the operation test to the thin-film 
lead which is soft and easy to deform and to perform for each compact 
semiconductor device an efficient aging test under a uniform, proper 
condition when a great number of such devices are to be tested. 
Consequently, the operation test under a thermal environmental condition 
has not been conventionally accomplished hitherto, which makes it quite 
difficult to correctly detect a defective device or a semiconductor device 
having a latent defect. 
It is therefore an object of the present invention to provide a 
semiconductor device for which an operation test under a thermal 
environment can be efficiently achieved. 
Another object of the present invention is to provide a semiconductor 
device for which a large-quantity test can be efficiently accomplished. 
Another object of the present invention is to provide a semiconductor 
device which has, after passing an appropriate test, a high reliability. 
Still another object of the present invention is to provide a method for 
producing a semiconductor device for which a large-quantity test can be 
efficiently achieved. 
Another object of the present invention is to provide a tape carrier 
capable of effectively accomplishing a large-quantity operation test. 
Further another object of the present invention is to provide a technology 
enabling an aging of a semiconductor pellet for a tape carrier type 
semiconductor device. 
These and other objects and the novel features of the present invention 
will be apparent from the following detailed description taken in 
conjunction with the accompanying drawings. 
The representative features of the invention disclosed in this application 
can be briefly described as follows. 
That is, a tape carrier is prepared which comprises a power trunk line 
including an electric connection as a branch of a power lead for each tape 
carrier unit and a ground trunk line having an electric connection as a 
branch of a ground lead for each tape carrier unit, the power and trunk 
lines being continuously formed along the longitudinal direction of the 
tape carrier, and a lead for a control signal for establishing an electric 
conduction along the longitudinal direction of the tape carrier via an 
aging wiring for semiconductor pellets to effect a simultaneous multipoint 
bonding on the tape carrier, the control signal lead being formed on the 
tape carrier. By mounting the semiconductor pellets having the aging 
wiring on the tape carrier, it is enabled to apply the power voltage and 
to supply the control signal to each of the plurality of the semiconductor 
pellets, and hence the operation test can be simultaneously conducted for 
the semiconductor pellets mounted on the tape carrier having an arbitrary 
length. This provision enables a plurality of semiconductor devices 
mounted on the tape carrier to be subjected to an aging, namely, a 
reliability test under a thermal environment and in the operating state, 
and hence an efficient reliability test can be achieved with an increased 
effect of the mass production. Consequently, a highly reliable 
semiconductor device can be provided.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 is a perspective view of the semiconductor pellet incorporated into 
the semiconductor device as an embodiment of the present invention, FIG. 2 
is a cross-sectional view along a line II--II of the semiconductor pellet, 
and FIG. 3 is a cross-sectional diagram showing a portion of the 
semiconductor device as the embodiment. Furthermore, FIG. 4 is a plan view 
illustrating a tape carrier applied to the production of the semiconductor 
device as the embodiment, whereas FIG. 5 is an explanatory diagram 
demonstrating an aging of the semiconductor pellet. 
The semiconductor device of the embodiment is so-called of a chip-on-board 
(COB) type. That is, referring to FIG. 3, a semiconductor pellet 2 is 
mounted on a wiring board 1 comprising a printed circuit board with the 
face of the pellet 2 up (in the face up state), and an electrode pad 3 of 
the semiconductor pellet 2 is electrically connected via a lead 4 to an 
electrode 1a, the lead 4 being formed with a copper foil having a 
thickness of about 35 .mu.m. A polyimide film 5 is fixed to a portion of 
the lead 4. 
In the semiconductor pellet 2 incorporated into the semiconductor device by 
use of the simultaneous multipoint bonding (gang bonding), a wiring 6 
including a wiring 6a and a wiring 6b is formed between electric pads 3a 
and 3b and between electric pads 3c and 3d formed along two opposing edges 
of a plurality of electric pads 3 as shown in FIG. 1. The wirings 6a and 
6b are utilized as the aging wirings in this embodiment. 
FIG. 2 is a cross-sectional diagram illustrating the relationships between 
the electric pads 3c-3d and the aging wiring 6b. The aging wirings 6a and 
6b are formed, like the ordinary internal wiring, with aluminum (Al) 
disposed beneath a passivation layer, and the electric pad 3 is formed to 
protrude into a hole portion 7a in the passivation layer. The electric pad 
3 is of a bump electrode structure and can be formed, for example, in a 
3-layer structure in which chromium (Cr), copper (Cu), and gold (Au) are 
sequentially fixed onto the aging wirings 6a and 6b. The wirings 6a and 6b 
may be configured in various structures. The wirings 6a and 6b may be 
simultaneously formed when manufacturing the multilayer wiring of the 
semiconductor pellet or may be formed in the different processes. If the 
wirings 6a and 6b are simultaneously formed together with the multilayer 
wiring, the multilayer internal wiring of two or three layers may be used 
for the formation of the aging wirings. The material of the wirings may be 
aluminum, polycrystalline silicon having a low resistance, or a refractory 
metal layer. 
The semiconductor device of the present embodiment is produced by use of 
the tape carrier of FIG. 4. The tape carrier 8 includes as a base a 
longitudinal polyimide film 5 on which a plurality of tape carrier units 
8a having a predetermined lead pattern to be applied to a semiconductor 
pellet are continuously formed in the direction to the right side of the 
diagram, the tape carrier 8 further including a wiring pattern formed 
thereon. On both sides in the transverse direction of the tape carrier 8, 
there are formed feed holes 9 with a fixed pitch along the entire film 5. 
Moreover, in the film 5 located outside of the feed holes 9, a power trunk 
wiring 10 and a ground trunk wiring 11 are linearly and continuously 
formed along the longitudinal direction in the intermediate and lower 
sections of the diagram, respectively. 
A semiconductor pellet mount section 12 is disposed at a central portion of 
the tape carrier unit 8a and a plurality of leads 4 each having an 
internal end are arranged in a predetermined shape on an internal 
periphery of the mount section 12. In addition, four through holes 13 are 
disposed on the external periphery of the mount section 12 so as to 
enclose the mount section 12, and each lead 4 is bridged to the holes 13. 
Among the leads 4 extending from the mount section 12, the power lead 4a is 
branched from the power trunk line 10 and these components are formed in a 
unit as an electric wiring. 
Moreover, among the leads 4 extending from the mount section 12, the ground 
lead 4b is branched from the ground trunk line 11 and these components are 
formed in a unit as an electric wiring. Consequently, when the 
semiconductor pellet 2 is fixed by use of the gang bonding on the chip 
carrier 8, the internal ends of the power leads 4a and the ground lead 4b, 
respectively can be fixed to the power electrode pad 3e and the ground 
electrode pad 3f of the semiconductor pellet 2, respectively. As a result, 
when a power supply E (e.g. see FIG. 5) is installed between the power 
trunk line and the ground trunk line 11 to apply a predetermined test 
voltage, the power voltage can be applied to all semiconductor pellets 
mounted on the tape carrier 8. 
In addition, among the leads 4 arranged on the right and left sides of the 
mount section 12 for the tape carrier unit 8a, two leads located at the 
top and bottom are used as the control signal leads 4c and 4d. The other 
leads 4 are electrically disconnected between the adjacent tape carrier 
units, whereas the control signal leads 4c and 4d are electrically 
connected by use of a connection wiring 15 between the adjacent tape 
carrier units. 
Since the semiconductor pellets 2 are fixed on the tape carrier 8 by the 
bonding, namely, the tape carrier leads 4 and the pad electrodes 3 of the 
semiconductor pellet are subjected to the gang bonding, the internal end 
of the control signal lead 4c and the internal end of the lead 4d can be 
fixed to the electric pad 3c or 3d and the electric pad 3a or 3d, 
respectively for each tape carrier unit 8. As a consequence, the control 
signal leads 4c and 4d formed in the tape carrier unit 8a are electrically 
connected between the tape carrier units through the aging wirings 6a and 
6b formed on the semiconductor pellet 2. As a result, by using the 
semiconductor pellet of the present invention also for the control signal 
lead, the electric conduction is established through the entire tape 
carrier 8. Consequently, when the control signals .phi.1 and .phi.2 are 
applied to the control signal leads 4c and 4d, respectively, the operation 
test can be conducted in a state where the control signals are 
simultaneously applied to the semiconductor pellets mounted over the tape 
carrier 8. The aging wirings 6a and 6b can be subjected to a disconnect 
processing if necessary. 
As described above, since the semiconductor pellets 2 are mounted on the 
tape carrier 8, the power voltage E can be applied to all the 
semiconductor pellets 2 on the overall tape carrier 8, thereby effecting 
the conduction test with the control signals .phi.1 and .phi.2 being 
supplied thereto. As shown in FIG. 5, therefore, the conduction test can 
be achieved so that a plurality of pellets are simultaneously subjected to 
the aging by installing a plurality of tape carriers each being rolled up 
as a volume in a compact state into a thermostatic bath. 
The semiconductor device of the embodiment is produced as follows. First of 
all, a silicon wafer in the shape of a wafer is processed through the 
thermal diffussion, the oxide film creation, and the CVD film creation so 
as to form a semiconductor IC 2a and a multilayer wiring layer 2b 
containing aging wirings. And then a probe test is conducted on the wafer 
to determine whether or not the aging wirings are acceptable. Next, the 
wafer is divided by the dicing process to obtain semiconductor pellets. 
Thereafter, the aging is achieved for the tape carrier 8 on which the 
semiconductor pellets 2 are fixed by the gang bonding, and then the probe 
test is executed for each tape carrier unit 8a to select the acceptable 
products. For the tape carrier unit 8a on which the acceptable 
semiconductor pellet is mounted, the lead 4 is cut off at a position of 
the hole 13 disposed in the film of FIG. 4. The unnecessary portion of the 
tape carrier is then removed, thereby obtaining an acceptable product in 
which the semiconductor pellet 2 and the lead 4 fixed thereto are formed 
in a unit. Thereafter, a top end of the lead 4 fixed to the separated 
semiconductor pellet 2 is bonded with the electrode 1a of the wiring board 
1, thereby completing the production of the semiconductor. 
Since the semiconductor device of this embodiment thus produced includes a 
semiconductor pellet 2 undergone such a sufficient aging as described 
above and then mounted on the device, a quite high reliability can be 
developed without any defects remaining in the semiconductor device. 
In addition, with the tape carrier 8, the probe test can be conducted on 
the semiconductor pellet 2 of each tape carrier unit 8a while executing 
the aging process on the semiconductor pellet 2 or immediately after the 
aging if the control signal leads 4c and 4d of the adjacent tape carrier 
unit are cut off at the connecting portion 15. Consequently, a latent 
defect which is restored to the normal state when the product is left to 
stand for a certain period of time after the aging is conducted and which 
cannot be therefore detected can be effectively detected because the probe 
test is achieved immediately after the aging is conducted. 
As an aging method, it can be considered that a portion of the tape carrier 
is cut away and for the semiconductor pellet 2 mounted on the separated 
portion, the electric connections such as for the power supply, grounding 
potential, and control signals are established for each aging process. 
Such troublesome procedures are not required when the tape carrier 8 of 
the embodiment is used. Since the simultaneous aging is possible for all 
the semiconductor pellets over the entire tape carrier 8, the long-period 
and large-quantity aging is enabled during the same processing time as 
compared with the case described above. Consequently, the reliability of 
the semiconductor device can be greatly improved. 
Although the present invention has been concretely described with reference 
to an embodiment of the present invention, it is not restricted by the 
embodiment. The embodiment can be modified in various fashions without 
departing from the scope and spirit of the present invention. 
As the test wiring 6 to be formed simultaneously with the creation of the 
multilayer wiring layer 2b of the semiconductor pellet 2 or in a separate 
process, it is only required to disposed a wiring structure establishing a 
short circuit between the control signal pad electrodes 3a and 3b or 
between the electrodes 3c and 3d. As a consequence, a jumper wire other 
than the wirings associated with the multilayer wiring layer may be used 
for the short-circuit wiring between the pads. This jumper wire has an 
effect that the operation to disconnect the wire when necessary is 
facilitated. 
For example, although the power trunk line and the ground trunk line are 
formed in the marginal film region outside the feed holes, they are not 
restricted by the configuration, namely, the other marginal portion of the 
film region may also be used. 
Moreover, the tape carrier includes two control signal leads located at the 
top and the bottom of the diagram; however, the number of the control 
signal leads, the locations for the leads, and the shape pattern are not 
restricted by the embodiment. Consequently, the aging wirings of the 
semiconductor pellets to which the control signal leads are connected are 
similarly not restricted by the embodiment. 
Furthermore, the shape of the film for each tape carrier unit and the lead 
pattern formed thereon are naturally not restricted by the embodiment. 
The description of the invention has been made with reference to the 
utilization field as the background of the invention mainly realized by 
the inventors, namely, to a case where the invention is applied to the 
so-called COB-type semiconductor; however, the present invention is not 
restricted by this case but it is a technology which can also be applied 
to any semiconductor devices using the tape carrier system for the 
production thereof regardless of the external shape of the package or the 
like. 
As noted previously, in recent semiconductor devices, the higher 
reliability is required. To this end, the aging is achieved as a 
reliability test in which a semiconductor device is subjected to an 
electrical operation state under a thermal environment of the state where 
the device is heated. 
According to the present invention, even for the semiconductor device 
associated with the tape carrier system, the aging of the semiconductor 
device can be easily achieved, and hence the electrical operation test in 
which the power voltage is applied to the device and further the control 
signals are applied thereto can be achieved as the aging for the 
semiconductor device in the ordinary operating state. 
In addition, according to the present invention, a plurality of 
semiconductor pellets in the tape carrier state can be subjected to 
various tests such as the aging test and the operation test under a 
thermal environment in a state where each semiconductor pellet is not 
manually handled. Consequently, the semiconductor device of the present 
invention, namely, the Tape Automated Bonding (TAB) product allows the 
large-quantity test which has been conventionally difficult to be 
automatically achieved without any human intervention, which enables the 
test processes to be quite efficient. 
The semiconductor device of the present invention allows the operation test 
to be efficiently accomplished under a thermal environment. 
The semiconductor device of the present invention enables the 
large-quantity test to be efficiently achieved. 
According to the present invention, there is provided a highly reliable 
semiconductor device after a proper test is finished. 
According to the present invention, there is provided a method for 
manufacturing a semiconductor device capable of efficiently conducting the 
large-quantity test. 
According to the present invention, there is provided a tape carrier 
capable of efficiently accomplishing the large-quantity test. 
The effect of the present invention is as follows. 
(1) A tape carrier is prepared which comprises a power trunk line including 
an electric connection as a branch of a power lead for each tape carrier 
unit and a ground trunk line having an electric connection as a branch of 
a ground lead for each tape carrier, the power and trunk lines being 
continuously formed along the longitudinal direction, and a lead for a 
control signal for establishing an electric conduction along the 
longitudinal direction via an aging wiring for semiconductor pellets to be 
mounted. By mounting the semiconductor pellets having the aging wiring on 
the tape carrier, it is enabled to apply the power voltage and to supply 
the control signal to each of the plurality of the semiconductor pellets, 
and hence the conduction (operation) test can be simultaneously conducted 
for the semiconductor pellets mounted on the tape carrier having an 
arbitrary length. 
(2) The operation (conduction) test is conducted by heating the device to a 
predetermined temperature, and hence the aging can be simultaneously 
effected for all semiconductor pellets mounted on the tape carrier having 
an arbitrary length. 
(3) Since the aging can be simultaneously conducted for a great quantity of 
semiconductor pellets according to (2) above, the large-quantity test can 
be efficiently achieved within a predetermined period of time, thereby 
lowering the cost of the tape carrier type semiconductor device. 
(4) For the similar reason to that of (3) above, the large-quantity test 
can be efficiently effected and the aging can be achieved for a plurality 
of semiconductor pellets in the compact state; as a result, a long-time 
aging is enabled and the reliability of the semiconductor device is 
improved. Incidentally, it is noted that the actual aging time for 
"long-time aging" depends on the particular circumstances and device 
requirements and can vary extensively. For example, a typical range would 
be from as short a time as two hours to as long a time as 20 days. 
(5) According to (2) above, by disconnecting the control signal lead 
between the adjacent tape carrier units during or immediately after the 
aging on a semiconductor pellet, the probe check can be executed on the 
semiconductor pellet for each tape carrier unit immediately after the 
aging. Consequently, a defect which is restored with a lapse of time can 
be detected by the probe check, and hence a highly-reliable semiconductor 
device can be provided for the user. 
(6) Based on (1)-(5) above, a low-priced tape carrier type semiconductor 
device having a high reliability can be supplied to the user.