JPS59143338A - Semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To obtain a monolithic IC which shortens the time of signal delay and has a high operating speed without the generation of malfunctions by a method wherein a light emitting element and a light receiving element are formed on the same substrate as a semiconductor substrate provided with an IC element, and signal transmission by means of electromagnetic waves is performed therebetween. CONSTITUTION:Input terminals 2a-2c consisting of bonding pads are provided at one end of the substrate 1 of GaAs, etc., and an output terminal 3 of the same structure at the other end, and an internal circuit 4 such as an FET is formed by being positioned therebetween. It is connected to the input terminals and the output terminal via wirings 5a1-5a3 and 5b, respectively. Next, the light receiving elements 6a-6c put in conduction state respectively by light irradiation are connected between the wirings 5a1-5a3 and a power source voltage VCC. The light emitting element 7 is connected between the wiring 5b and the ground point of the circuit. When light signals are made incident from an external light emitting device 10a to the elements 6a-6c in such a constitution, the elements come in conduction state and operates the circuit 4, thus making the element 7 emit light only during this time, and enabling the detection in the light emitting device 10b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor integrated circuit device, and in particular to a monolithic integrated circuit device which is structured so that signals can be transmitted between elements within the integrated circuit or between an internal circuit and an external device using light. Related to circuit devices.

Conventionally, semiconductor integrated circuits have generally been inspected at the wafer stage by applying a probe (needle) to a bonding pad to determine whether the circuit is operating normally. Therefore, there is a drawback that the bonding pad is damaged by the probe during inspection. Further, as the degree of integration of semiconductor integrated circuits increases or the number of pins increases, the number of items in the inspection process is increasing exponentially. For this reason, the currently commonly used testing method using bonding tests significantly increases testing time, and it is not possible to directly obtain operational information of some circuits within a semiconductor integrated circuit. There was a problem that accurate inspection could not be performed.

Furthermore, signal transmission in semiconductor integrated circuit devices has conventionally been carried out between each element constituting an integrated circuit using an electrically conductive material such as polycrystalline silicon or aluminum formed on a semiconductor chip. By using it as a wiring, electrical signals are used.

In addition, signal transmission between the semiconductor integrated circuit and the external electronic device is achieved by, for example, connecting the bonding pad and the lead terminal with open wire bonding, and connecting the lead terminal with the external electronic device. This was done by electrically connecting them with an electrically conductive material.

However, when signals are transmitted between internal elements of a semiconductor integrated circuit or with external devices using electrical wiring, a delay occurs in signal transmission due to the capacitance and resistance of the electrical wiring. %, as the degree of integration in semiconductor integrated circuits increases, the length of internal wiring becomes relatively longer, and as a result, signal delays due to wiring become increasingly large. For example, when elements that transmit signals within a semiconductor integrated circuit are relatively far apart, the signal delay becomes more significant than when signals are transmitted between elements that are close to each other. Moreover, due to capacitance coupling with electrical wiring or elements within the integrated circuit, there is a risk that the circuit may malfunction due to the influence of signals from nearby wiring or elements.

Therefore, the present invention has been developed by forming a light emitting element and a light receiving element on the same substrate (chip) as the semiconductor substrate on which the elements constituting the circuit are formed, so that signals can be transmitted without contact with external devices. enable communication, thereby
To prevent a bonding pad from being damaged during an integrated circuit testing process. In addition, each internal circuit can be inspected individually, thereby reducing inspection time and
The purpose is to improve the reliability of testing.

Furthermore, the present invention enables signal transmission between elements or circuits located far apart from each other in an integrated circuit using radiation, e.g., electromagnetic waves such as light, thereby reducing signal delay time. The purpose is to improve operating speed and make malfunctions less likely to occur.

The present invention will be explained below using the drawings.

FIG. 1 shows an example in which signals are transmitted between an integrated circuit and an external device using a light-receiving element and a light-emitting element formed on a semiconductor substrate, so that circuit inspection can be performed without contact. An example will be shown below.

In the figure, 1 is a semiconductor substrate such as a GaAs (gallium arsenide) semiconductor. 2a to 2C are input terminals connected to bonding pads formed on the semiconductor substrate 1, and 3 is a similar output terminal. Reference numeral 4 denotes an internal circuit formed on the semiconductor substrate 1 using active elements such as yIIIT (field effect transistor), and this internal circuit 4 receives the above input via wirings 5al to 5al and 5b. It is connected to the terminals 2a to 2C and the output terminal 3.

Light receiving elements 6a to 6C are provided between the wirings 5a1 to 5al and the power supply voltage v0°, respectively, and are made conductive when irradiated with light.

Further, a light emitting element 7 is provided between the wiring 5b and the ground point of the circuit. The light receiving elements 6a to 60 and the light emitting element 7 can be formed together with other circuit elements (puT) on a GaA9 semiconductor substrate using known semiconductor manufacturing techniques.

In the above circuit, when an appropriate optical signal is input from the external light emitting device flOa to each of the light receiving elements 6a to 60, the light receiving elements 6a to 6C are rendered conductive only while being irradiated with light. A power supply voltage v0° is supplied to the wirings 5a1 to 5al. Therefore, the power supply voltage V. A high-level signal is input to the internal circuit 4 through the wiring that has been completely supplied with 0's.

As a result, when the internal circuit 4 performs a predetermined operation and the output is set to a high level, the light emitting element 7 connected between the wiring 5b and the ground point lights up while the output of the internal circuit 4 is at a high level. only emits light. By detecting this with the external light receiving device 10b, the bonding pad (2a
It is possible to test whether or not the internal circuit 4 operates normally without contacting 2C and 3) with a probe. As a result, there is no risk that the bonding pad will be damaged by the probe during testing.

Next, an embodiment in which the present invention is applied to determine whether the operation of some circuits inside an integrated circuit is normal or abnormal will be described with reference to FIG.

In the figure, 2a to 2f are input terminals consisting of bonding pads like the input terminals in the embodiment of FIG. 1, and 3 is an output terminal. Further, 4a to 4C are internal circuits each having a different function, and internal circuits 4a,
4N) and internal circuit 4C are wiring 5Q+, 5cl
electrically connected by. And this wiring 5
In the middle of c1 and 5c2, signal conversion circuits 8a and Rb each consisting of a negative pair of receiving and receiving elements and a light emitting element are provided.

These signal conversion circuits 8a, 8b are each supplied with the internal circuit 4a via the wiring 5cl+5ct.

It has the function of converting the output signal of 4b into an optical signal and oscillating it to the outside, and the function of converting the optical signal supplied from the outside into an electric signal and outputting it to the internal circuit 4c.

Therefore, when inspecting the operation of internal circuits 4a and 4b, input terminals 2a to 2c (or 2d to 2f)
It is sufficient to input an electrical input signal from the signal conversion circuit 8a (or Flb') and detect the signal transmitted from the signal conversion circuit 8a (or Flb') by the external device 11 for determination.

In addition, when inspecting the operation of the internal circuit 4c, an optical signal is inputted from the external device 11 to the signal conversion circuit 8F1゜8b on the board 1 to operate the internal circuit 40, and the output is sent to the output terminal as an electrical signal. 3. Take it out. Then, it is determined whether the operation is normal or abnormal based on the combination of the input signal and output signal.

In this way, in the embodiment shown in Fig. 2, the probe must be placed on the input/output pad for inspection, but it is now possible to easily inspect each internal circuit, which was previously impossible. . Therefore, the number of combinations of input signals is considerably reduced compared to the conventional method in which input is made only from input terminals, and inspection time is significantly shortened and inspection accuracy is also improved.

Next, when transmitting a message between elements or circuits formed at relatively distant positions in an integrated circuit, for example, two elements or circuit parts may each be provided with a light emitting element and a light receiving element. put. Then, both end surfaces of the optical fiber fixed by a package etc. are placed to face the above-mentioned light emitting element and light receiving element respectively, and the electric signal is converted into an optical signal and passed through the optical fiber, and is converted back into the original electric signal. By converting, the signal can be transmitted without any delay.

In addition, by facing mutually related integrated circuits formed on separate semiconductor substrates and positioning and fixing them so that the light-emitting element and light-receiving element formed on the substrates are aligned, It is also possible to enable transmission of signals.

As explained above, according to the present invention, since the light receiving element or the light emitting element is provided in a desired part of the semiconductor substrate on which the integrated circuit is formed, non-contact signal transmission by light becomes possible. By replacing part of the signal transmission through electrical wiring with optical signal transmission, it is possible to minimize the extension of inspection time that accompanies an increase in the degree of integration.

Further, since the circuit can be tested without using the bonding pad, damage to the pad can be prevented. Furthermore, it is possible to transmit signals without inductive phenomena such as capacitive coupling in electrical wiring, reducing signal delays and preventing circuit malfunctions.

In the above embodiment, a light emitting element and a light receiving element are provided along with a circuit element on a GaAs semiconductor substrate, but the present invention is not limited to e and As semiconductors.

Also, signal transmission is not limited to light.

For example, it is known that silicon diodes emit heat rays in relation to the bandgap voltage, so a diode formed on a silicon semiconductor substrate converts an electrical signal into a heat ray signal and transmits the signal. It is also possible.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing one embodiment of a semiconductor integrated circuit device according to the present invention, and FIG. 2 is a schematic block diagram showing another embodiment of the present invention. 1... Semiconductor substrate, 2a to 2f... Input terminal (ponding pad), 4, 4a, 4b, 4a... Internal circuit, 6a to 6c... Signal conversion element (light receiving element), 7.
...Signal conversion element (light emitting element).

Claims (1)

[Claims] 1. On the same substrate as the semiconductor substrate on which the integrated circuit consisting of active elements and passive elements or only one of these is formed, there is a signal conversion element that receives radiation signals and converts them into electrical signals, and a signal conversion element that converts the electrical signals of the internal circuit. 1. A semiconductor integrated circuit device comprising only a signal conversion element that converts into a radiation signal, or one of these elements.