Semiconductor integrated circuit device

There is disclosed a semiconductor integrated circuit device comprising: an external input signal lead provided outside a semiconductor chip; a power supply lead provided outside the semiconductor chip; a first electrode connected to an internal circuit on the semiconductor chip, and arranged close to the external input signal lead, wherein when the circuit is caused to be operative, the first electrode is connected to the external input signal lead; and a second electrode connected to the first electrode on the semiconductor chip, and arranged close to said power supply lead, wherein when the circuit is not caused to be operative, the second electrode is connected to the power supply lead. This invention is applicable to the device wherein there are provided a plurality of internal circuits. In this case, a plurality of the first electrodes drawn out from the internal circuits are arranged close to the external input signal lead, and a plurality of the second electrodes similarly drawn out from the internal circuits are arranged close to the power supply lead.

BACKGROUND OF THE INVENTION 
This invention relates to a semiconductor integrated circuit device, and 
more particularly to a device capable of exhibiting different functions by 
the same semiconductor chip. 
In general, in semiconductor integrated circuit devices, there are 
instances where non-connection (NC) terminals which are not connected to 
the circuit exist in the semiconductor chip. In such case, with a view to 
adding a new function or functions to semiconductor integrated circuits 
through the implementation of semiconductor integrated circuits of a 
multi-functional structure, there have been many occasions where NC 
terminals are used as terminals for inputting external signals. 
In such cases in order not to bring on lowering of productivity, even in 
cases where a new function is added, it is necessary to maintain the 
fundamental function conventionally given as it is, to thus ensure 
compatibility. In the case where a NC terminal is used as the electrode 
for inputting an external signal and the internal circuit is not used, if 
that NC terminal is brought into a floating state, there is the 
possibility that an erroneous operation of the internal circuit may take 
place. Accordingly, it is required to hold the NC terminal at a positive 
or negative power supply potential. 
For this reason, in conventional devices, in the case where an internal 
circuit is formed with a view to adding a new function in the 
semiconductor chip of the package, when this internal circuit is used, a 
lead for inputting an external signal is connected to an electrode drawn 
out from the internal circuit for the purpose of inputting an external 
signal In this case, when this internal circuit is not used, it is 
necessary to connect that external signal input electrode to a power 
supply terminal provided outside the chip so that a potential on the 
external signal input electrode is not placed in a floating state. 
Accordingly, it is necessary that the electrode be provided at a position 
close to the power supply terminal. For this reason, internal wiring is 
required. 
However, since a semiconductor manufacturing mask is required in order to 
form such an internal wiring, two kinds of masks must be prepared for the 
case where the internal circuit is made operative and the case where the 
internal circuit is not made operative. Thus, there results increased cost 
and lowered productive efficiency. 
Further, it is conceivable to take measures to connect the internal circuit 
and one external signal input electrode to further connect the external 
signal input terminal and an external signal input lead, or to connect the 
external signal input electrode and a power supply lead. However, in this 
case, it is required that the external signal input lead and the power 
supply lead be adjacent to each other, and that the external signal input 
electrode be provided in the vicinity of these leads. This results in the 
problem that the circuit design and the chip layout design are greatly 
restricted. 
SUMMARY OF THE INVENTION 
Accordingly, an object of this invention is to provide a semiconductor 
integrated circuit device which is capable of attaining reduced cost and 
improved productivity, and which is of a structure such that the circuit 
design and the layout design of the chip are not restricted. 
According to the present invention, there is provided a semiconductor 
integrated circuit device comprising: a lead for inputting an external 
input signal provided outside a semiconductor chip, a lead for a power 
supply provided outside said semiconductor chip, a first electrode 
connected to an internal circuit on said semiconductor chip, and arranged 
close to said lead for inputting an external input signal, wherein when 
said circuit is caused to be operative, said first electrode is connected 
to said lead for inputting an external input signal, and a second 
electrode connected to said first electrode on said semiconductor chip, 
and arranged close to said lead for a power supply, wherein when the 
circuit is not caused to be operative, said second electrode is connected 
to said lead for power supply. 
In accordance with this invention, since there are provided first and 
second electrodes close to an external signal input lead and a power 
supply lead, respectively, when the circuit is caused to be operative, the 
first electrode and the external signal input lead are connected. Thus, a 
signal is inputted from the external to the circuit. In contrast, when the 
circuit is not made operative, the second electrode connected to the first 
electrode and the power supply lead are connected. As a result, a 
potential on the first electrode is held at a power supply potential. 
Thus, an erroneous operation is prevented. Since selection of functions is 
carried out by changing the connection relationship between the electrodes 
and the leads without affecting the internal wiring of the semiconductor 
chip by any means in a manner stated above, it is sufficient to use a 
single kind of a semiconductor manufacturing mask for this purpose. In 
addition, by providing a potential fixing electrode, there is no 
inconvenience such as the circuit design and the layout design being 
restricted by the positional relationship of the power supply lead and the 
external signal input lead.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Preferred embodiments of this invention will now be described with 
reference to the attached drawings. 
Initially referring to FIG. 1, there is shown the configuration of a 
semiconductor integrated circuit device according to an embodiment. An 
internal circuit 102 newly added is connected to an external signal input 
electrode 104 by way of an internal wiring 103, and the external signal 
input electrode 104 is connected to a potential fixing electrode 105. The 
external signal input electrode 104 is provided close to an external 
signal input lead 109, and the potential fixing electrode 105 is provided 
close to a power supply lead 108 and adjacently to a power supply 
electrode 106. The power supply electrode 106 is connected to the power 
supply lead 108 by means of a bonding wire 107, and serves to deliver 
power to respective circuits in a semiconductor chip 101. 
In the case where the internal circuit 102 is caused to be operative, as 
shown in FIG. 2, the external signal input electrode 104 and the external 
signal input lead 109 are connected by means of a bonding wire 110, and 
the potential fixing electrode 105 is not connected to any lead. In 
contrast, in the case where the internal circuit 102 is not caused to be 
operative, as shown in FIG. 3, the external signal input electrode 104 is 
not connected to any lead, and the potential fixing electrode 105 is 
instead subjected to double bonding to the power supply lead 108 together 
with the power supply electrode 106 by using a wire 111. Thus, a potential 
on the external signal input electrode 104 is fixed at a power supply 
potential, and is not therefore brought into a floating state. As a 
result, erroneous operation of the internal circuit 102 is prevented. 
As described above, in accordance with this embodiment, by changing the 
designation of the connecting portion of the wire bonding, it is possible 
to easily make selection of functions. Further, since the wiring 103 in 
the semiconductor chip 101 is fixed, it is sufficient to use a single kind 
of a semiconductor manufacturing mask for this purpose. Accordingly, it is 
possible to deliver many kinds of products by using a single semiconductor 
chip 101 without addition of mask. Thus, reduced manufacturing cost and 
improved productivity can be attained. In addition, by providing the 
potential fixing electrode, the degree of freedom in design can be ensured 
irrespective of the positions of the external signal input lead and the 
power supply lead. 
It should be noted that the above-described embodiment is only an example, 
and therefore this invention may be applied to other devices. For example, 
this invention may be applied not only to a device provided with one 
internal circuit newly added but also to a device provided with two or 
more internal circuits newly added. 
The device shown in FIG. 4 includes two internal circuits 102a and 102b. In 
this case, external signal input electrodes 104a and 104b, and potential 
fixing electrodes 105a and 105b respectively are provided for the internal 
circuits 102a and 102b. The internal circuit 102a, the external signal 
input electrode 104a, and the potential fixing electrode 105a are 
connected by using an internal wiring 103a. Further, the internal circuit 
102b, the external signal input electrode 104b and the potential fixing 
electrode 105b are connected by using an internal wiring 103b. 
The external signal input electrode 104a is provided close to the external 
input lead 109a for delivering a signal to be inputted to the internal 
circuit 102a, and the external signal input electrode 104b is provided 
close to the external input lead 109b for delivering a signal to be 
inputted to the internal circuit 102b. In addition, the potential fixing 
electrodes 105a and 105b are both positioned at portions adjacent to the 
power supply electrode 106, respectively. 
As described above, in this embodiment, there is employed an arrangement 
such that wire bonding can be independently implemented to any one of the 
external signal input lead and the potential fixing lead for respective 
internal circuits 102a and 102b. For example, in the case where the 
internal circuit 102a is used and the internal circuit 102b is not used, 
the external signal input electrode 104a and the external signal input 
lead 109a are connected, and the potential fixing electrode 105b and the 
power supply lead 108 are connected. Thus, only by changing the 
designation of the connection of the wire bonding, it is possible to carry 
out selection of functions. 
As described above, in accordance with this invention, in the case of 
operating a newly added circuit, the first electrode and the external 
signal input lead are connected so that a signal is inputted to the 
circuit. In contrast, in the case of allowing the circuit to be 
inoperative, the second electrode connected to the first electrode and the 
power supply lead are connected so that a potential on the first electrode 
is held at a power supply potential to prevent an erroneous operation of 
the circuit Accordingly, selection of functions can be carried out by 
using a single kind of semiconductor manufacturing mask without affecting 
the internal wiring of the semiconductor chip by any means. Thus, reduced 
cost and improved productivity can be attained.