Semiconductor Integrated Unit

1. Field of the Invention

The present invention relates to a semiconductor integrated circuit device containing a temperature sensor. 2. Description of the Related Art

A method of protecting a semiconductor device from temperature rising, is disclosed for example in JP-A-55-55539. In accordance with this method, the voltage across the emitter and collector of a bipolar transistor having a heat radiating board made of a magnetic substance is monitored to detect the temperature of that bipolar transistor. When the detected temperature rises up to a critical temperature, the magnetic heating is stopped to prevent the breakdown of the transistor due to the excessive temperature rise.

On the other hand, in JP-A-58-77329, there is proposed a semiconductor integrated circuit device in which when a power supply voltage exceeding the operating voltage range is applied, the temperature rise of a PN junction of the transistor constituting an internal circuit is prevented by providing a circuit for suppressing the circuit current by utilizing a reverse breakdown voltage of the PN junction.

However, in the method disclosed in JP-A-55-55539, the detection of the temperature of the semiconductor device and the interruption of the magnetic heating are performed outside, and not within the semiconductor device itself. Further, when the actual reliability test is performed, the semiconductor device is encapsulated in a package and then subjected to the aging. In this connection, different kinds of packages may have different radiating capabilities. Thus, even when the reliability test is performed with a certain kind of package, the rate of temperature rise of the PN junction may be different when it is encapsulated in a different package. Therefore, in this case, an additional work is required to perform the reliability test again for that different package.

On the other hand, in the semiconductor integrated circuit device disclosed in JP-A-58-77329, the circuit for suppressing the circuit current is constructed by bipolar transistors. Therefore, such construction is unsuitable for the MOS type semiconductor integrated circuit device.

The present invention has been made to solve the above-mentioned problem, and has an object to provide a semiconductor integrated circuit device which is capable of automatically preventing by itself the breakdown due to the excessive temperature rise.

Another object of the present invention is to provide a semiconductor integrated circuit device which is suitable for preventing the breakdown due to the temperature rise of a MOS type semiconductor integrated circuit device.

Still another object of the present invention is to provide a semiconductor integrated circuit device which is capable of, once the reliability test has been performed with any kind of package, preventing the breakdown due to the temperature rise whatever kind of package is used.

In order to attain the above objects of the present invention, there is provided a semiconductor integrated circuit device having a temperature sensor for controlling supply of an electric energy to a group of MOS integrated circuit elements on the basis of a detection output of the temperature sensor, the semiconductor integrated circuit device comprising: the temperature sensor including an element having a PN junction; an inverter to which an output of the temperature sensor is supplied and a controller for controlling supply of the electric energy to the group of MOS integrated circuit elements on the basis of an output of the inverter. The temperature sensor includes a PN junction diode and a resistor connected in series with the PN junction diode. The resistor is further provided at its one end with connection means for connecting it to a power supply. The resistor includes a resistance wire forming a body of the resistor and a contact which is provided at an intermediate point of the resistance wire to define a resistance value of the resistor, and connected to the connection means. The resistor is further provided with a bypass for short-circuiting a part of the resistance wire to reduce the resistance value. The controller includes a MOS transistor. The inverter includes a pair of MOS transistors.

Further, there is provided a semiconductor integrated circuit device having a temperature sensor for controlling supply of an electric energy to a group of MOS integrated circuit elements on the basis of a detection output of the temperature sensor, the semiconductor integrated circuit device comprising: the temperature sensor having a PN junction diode and a resistor connected in series with the PN junction diode; an inverter for receiving an output of the temperature sensor and having a pair of MOS transistors, the output of the temperature sensor being inputted to respective gates of the pair of MOS transistors; and a controller for controlling the supply of the electric energy to the group of MOS integrated circuit elements, the controller including a MOS transistor, the output of the inverter being inputted to a gate of the MOS transistor. Moreover, the resistor of the temperature sensor is provided at its one end with connection means for connecting it to a power supply. The resistor includes a resistance wire forming a body of the resistor and a contact which is provided at an intermediate point of the resistance wire to define a resistance value of the resistor, and connected to the connection means. The resistor is further provided with a bypass for short-circuiting a part of the resistance wire thereby to reduce the resistance value. The pair of MOS transistors of the inverter include a P-channel MOS transistor and an N-channel MOS transistor and connection means is provided to a source of the P-channel MOS transistor for connecting it to a power source. A drain of the P-channel MOS transistor and a source of the N-channel MOS transistor are both connected to the gate of the MOS transistor of the controller. The controller includes a P-channel MOS transistor and connection means is provided to a source of the P-channel MOS transistor for connecting it to the power source. The P-channel MOS transistor of the controller is connected at its drain to the group of MOS integrated circuit elements.

Further, there is provided a semiconductor integrated circuit device having a temperature sensor for controlling supply of an electric energy to a group of MOS integrated circuit elements on the basis of a detection output of the temperature sensor, the semiconductor integrated circuit device comprising: the temperature sensor having a PN junction diode and a resistor connected in series with the PN junction diode, a PN junction diode side of the series connection of the PN junction diode and the resistor being connected to a grounding side, while its resistor side is connected to a power supply side; an inverter for receiving an output of the temperature sensor, and having a pair of P-channel MOS transistor and N-channel MOS transistor, the output of the temperature sensor being inputted to gates of the MOS transistors, a drain of the P-channel MOS transistor and a drain of the N-channel MOS transistor providing an output of the inverter; and a controller for controlling supply of the electric energy to the group of MOS integrated circuit elements on the basis of the output of the inverter, the controller including a P-channel MOS transistor, the output of the inverter being inputted to a gate of the P-channel MOS transistor of the controller, a drain of the P-channel MOS transistor being connected to the group of MOS integrated circuit elements. Moreover, the temperature sensor has an output portion at a connection between the PN junction diode and the resistor. A source of the P-channel MOS transistor of the inverter is further provided with a connection terminal to be connected to a power source. A source of the P-channel MOS transistor of the controller is further provided with a connection terminal to be connected to the power source. The resistor is provided at its one end with connection means to be connected to the power supply. The resistor includes a resistance wire forming a body of the resistor and a contact which is provided at an intermediate point of the resistance wire to define a resistance value of the resistor, and the contact is connected to the connection means. The resistor is further provided with a bypass for short-circuiting a part of the resistance wire to reduce the resistance value.

According to the semiconductor integrated circuit device having the construction as described above, when the temperature of the device rises up to a level higher than a predetermined temperature, the output of the temperature sensor contained in the device is inverted by the inverter and then supplied to the gate of the MOS transistor connected between the internal circuit and the power source thereby to turn off the MOS transistor, whereby the supply of the power to the internal circuit can be automatically stopped. As a result, the breakdown of the internal circuit due to the excessive temperature rise can be automatically prevented by itself.

Moreover, since the breakdown of the internal circuit due to the temperature rise can be automatically preventing by itself, once the reliability test is performed with any kind of package, the breakdown of the internal circuit can be prevented whatever kind of package is used.

Further, since the inverter can be made of the MOS transistors, the semiconductor integrated circuit device is suitable for preventing the breakdown of the MOS type semiconductor integrated circuit device due to the temperature rise.

FIG. 1 is a circuit diagram showing the arrangement of a semiconductor integrated circuit device according to one embodiment of the present invention;

FIG. 2 is a plan (top) view showing the layout on a substrate of the arrangement shown in FIG. 1; and

FIG. 3 is a graphical representation showing an example of current-voltage characteristics of a PN junction diode which is used for a temperature sensor in the semiconductor integrated circuit device according to one embodiment of the present invention.

One embodiment of the present invention will hereinafter be described with reference to the accompanying drawings.

FIG. 1 is a circuit diagram showing the arrangement of a temperature sensor system of a semiconductor integrated circuit device according to one embodiment of the present invention.

In the present embodiment, an anode 11a of a PN junction diode 11 acting as a temperature sensor 10 and one end of a resistor 12 (its resistance is represented by R), which is a main heat source for a temperature to be detected by the PN junction diode 11, are connected in series with each other at a contact 13. The other end of the resistor 12 is provided with a power terminal 14 to which a predetermined voltage v (e.g., about 1.0 V) is applied. The power terminal 14 to which the power voltage v is applied is independent of a power terminal of the body of the semiconductor integrated circuit device, i.e., an internal circuit 30 including a memory, a logical circuit and the like which are made of a group of MOS integrated circuit elements. On the other hand, a cathode 11b of the PN junction diode 11 is grounded.

The anode 11a of the PN junction diode 11 is connected at the contact 13 to gates 16a and 18a of an N-channel MOS transistor 16 and a P-channel MOS transistor 18 constituting an inverter 20. In this connection, a power voltage Vcc is applied to a source 18b of the P-channel MOS transistor 18 through a power terminal 22 of the internal circuit 30. Moreover, a source 16b of the N-channel MOS transistor 16 is grounded. Drains 16c and 18c of the N-channel MOS transistor 16 and the P-channel MOS transistor 18 constituting the inverter 20 are connected to each other at a contact 23, and to a gate 24a of a P-channel MOS transistor 24. The P-channel MOS transistor 24 which constitutes switching means which is connected in series between the internal circuit 30 and a power supply (Vcc) for the internal circuit 30. The power voltage Vcc is applied through a power terminal 26 to a source 24b of the P-channel MOS transistor 24, of which a drain 24c is connected to the internal circuit 30. A part of the internal circuit 30 is also, as shown in FIG. 1, grounded. The internal circuit 30 is made up of a memory, a logical circuit and the like which are made of a group of MOS integrated circuit elements.

FIG. 2 is a plan view showing the layout on a semiconductor wafer of the circuit arrangement shown in FIG. 1. This circuit wiring is normally formed on a semiconductor substrate such as a silicon substrate. The typical components on the layout corresponding to those of the circuit of FIG. 1 are represented by the same reference numerals. The PN junction diode 11 has the anode 11a located in the center portion thereof and the cathode 11b having a size larger than that of the anode 11a. The anode 11a is connected at the contact 13 to the resistor 12 through a lead 105. Moreover, the cathode 11b is connected through contacts 110 adjacent to the anode 11a to a grounding conductor 115. The resistor 12 is constructed by a resistance wire 118 made of polysilicon, one end of the resistor 12 is connected at the contact 13 to the diode 11 and the other end thereof is connected at a contact 120, which is formed at a position selected so as to provide a desired resistance value, to an electrode 14 made of aluminium. The resistance wire 118 of the resistor 12 extends on the wafer with a length so that the resistance of the resistor 12 is variable by changing the position of the contact 120 or providing a bypass 122 at a part thereof for short circuiting a part of the resistor wire 118 to reduce the resistance value of the resistor 12, when manufactured, in correspondence to the critical current, which will be described later.

With the N-channel MOS transistor 16, the source 16b is connected through contacts 125 and a lead 130 to the grounding conductor 115, and the drain 16c is connected through contacts 135 to a lead 140. The lead 140 is connected through contacts 150 to the drain 18c of the P-channel MOS transistor 18 and connected through a contact 23 to the gate 24a of the P-channel MOS transistor 24. The gate 18a of the P-channel MOS transistor 18 is formed in the same layer as that of the gate 16a of the N-channel MOS transistor 16 and made of the same material (Normally, polysilicon) as that of the gate 16a of the N-channel MOS transistor 16. The gate 18a of the P-channel MOS transistor 18 is connected through the contact 13 to the lead 13 and the resistor 12. The source 18b of the P-channel MOS transistor 18 is connected through the contacts 155 to the electrodes 22, 26. Further, the source 24b of the P-channel MOS transistor 24 is connected through contacts 160 to the electrodes 22, 26, and the drain 24c thereof is connected through contacts 165 to a lead 170. The lead 170 is connected to the internal circuit 30 shown in FIG. 1.

Next, the description will be given to the operation of the semiconductor integrated circuit device according to the present embodiment which is constructed in the manner as described above.

The PN junction diode 11 has current-voltage characteristics as shown in FIG. 3. As seen from FIG. 3, the built-in potential of the PN junction of the PN junction diode 11 is reduced as the junction temperature T of the PN junction diode 11 rises, and as a result, the current flowing through the PN junction is increased.

In FIG. 1, the electric potential V.sub.Q at the anode 11a of the PN junction diode 11, i.e., the contact 13 corresponding to the output portion of the temperature sensor 10 is represented by the following expression;

where i represents the current passing through the resistor 12. As seen from the expression (1), the electric potential V.sub.Q is reduced as the current i passing through the resistor 12 is increased due to the rise of the junction temperature T.

Then, when the following relationship is established between the electric potential V.sub.Q and the threshold voltage V.sub.T1 of the P-channel MOS transistor 18 of the next stage,

the P-channel MOS transistor 18 is turned on and the N-channel MOS transistor 16 is turned off. As a result, the electric potential Vs at the contact 23 corresponding to the output portion of the inverter 20 is changed from the low level to the high level. As a result, the P-channel MOS transistors 24 of the next stage is turned off thereby to electrically separate the internal circuit 30 from the power source (Vcc), so that the circuit current is stopped.

The threshold voltage VT.sub.Tl Of the P-channel MOS transistor 18 is selected as being the same value as that of the internal circuit 30 of the semiconductor integrated circuit device. Then, in the reliability test, during the first aging or burn-in test, the current i with which the semiconductor integrated circuit device according to the present embodiment encapsulated with a certain kind of package begins the latch-up and the like, i.e., the critical current Ic is obtained by monitoring.

Then, since the following relationship is established,

the circuit current is automatically stopped when the junction temperature T rises up to the certain critical temperature, even if the kind of package is changed, by setting the resistance value R of the resistor so as to satisfy the following expression

As a result, it is possible to prevent the breakdown of the semiconductor integrated circuit device due to the latch-up and the like. Therefore, there is no need for performing the reliability test again.

As described above, according to the present embodiment, the breakdown of the semiconductor integrated circuit device due to the excessive temperature rise can be effectively prevented, and also, even if the kind of package is changed, there is no need for performing the reliability test again, so that only one reliability test with a certain kind of package is available.

In addition, the circuit for stopping the circuit current when the junction temperature T rises up to the critical temperature can be constructed by the MOS transistors and the PN junction diode. Therefore, the semiconductor integrated circuit device according to the present embodiment is suitable for the MOS type semiconductor integrated circuit device.

Although one embodiment of the present invention has been described in detail, modifications may be made without departing from the spirit of the invention.

For example, although the PN junction diode 11 is employed as the temperature sensor in the above-mentioned embodiment, the bipolar transistor may be employed as the temperature sensor.

As set forth hereinabove, according to the present invention, the breakdown of the internal circuit due to the temperature rise can be automatically preventing by the semiconductor integrated circuit device itself. Also, once the reliability test is performed with a certain kind of package, thereafter, the breakdown of the internal circuit can be prevented no matter what kind of package is used. Moreover, the semiconductor integrated circuit device of the present invention is suitable for the MOS type semiconductor integrated circuit device.