Semiconductor device and temperature characteristic inspection method

Abstract

To inspect the temperature characteristics of a bandgap reference circuit more accurately in an environment where an inspection temperature of a semiconductor device is not accurately known.SOLUTION: According to one embodiment, temperature dependences of a reference voltage and an absolute temperature proportional voltage are measured in advance for a plurality of samples before temperature characteristics of a bandgap reference circuit are inspected. Based on a difference ΔVref between a reference voltage of the bandgap reference circuit and the median value of the reference voltages of the plurality of samples at a predetermined temperature, a difference ΔVptat between the absolute temperature proportional voltage of the bandgap reference circuit at the predetermined temperature and the median value of the absolute temperature proportional voltages of the plurality of samples is calculated when the temperature characteristics are inspected.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a semiconductor device and a temperature characteristics testing method, for example, a semiconductor device including a bandgap reference circuit and a temperature characteristics testing method. [Background technology]

[0002] In recent years, information processing devices with functions such as navigation and audio have been installed in vehicles as in-vehicle electronic systems. Semiconductor devices used in such in-vehicle electronic systems are required to have high safety standards in accordance with ISO (International Standard Organization) 26262.

[0003] Therefore, semiconductor devices used in in-vehicle electronic systems have a temperature sensor that monitors the internal temperature in order to achieve high-speed processing within a temperature range (for example, −40 to 125° C.) where operation is guaranteed. Patent Documents 1 and 2 disclose semiconductor devices that include a band gap reference (BGR) circuit as a temperature sensor.

[0004] The bandgap reference circuit has variations in temperature characteristics due to, for example, manufacturing variations, etc. Therefore, when manufacturing the semiconductor device, the temperature characteristics of the bandgap reference circuit in each semiconductor device are inspected so that the temperature can be accurately measured within the temperature range in which operation is guaranteed.

[0005] For example, a semiconductor wafer on which a large number of IC (Integrated Circuit) chips, which are semiconductor devices, are formed is fixed on a temperature-adjustable wafer chuck, and the temperature of the wafer chuck is set to the minimum and maximum temperatures at which the semiconductor device is guaranteed to operate. At each set temperature, probes of a probe card are brought into contact with the semiconductor wafer to inspect the operation of each semiconductor device and inspect the temperature characteristics of the bandgap reference circuit in each semiconductor device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2017-198523 [Patent Document 2] Japanese Patent Application Publication No. 2020-106362 Summary of the Invention [Problem to be solved by the invention]

[0007] The inventors have found the following problems with semiconductor devices equipped with bandgap reference circuits. In the above-mentioned inspection, it has been thought that the inspection temperature of each semiconductor device on the semiconductor wafer (the temperature when the probe is brought into contact to inspect the temperature characteristics) would have an error of, for example, about ±1°C from the set temperature of the wafer chuck. However, the inventors' investigation revealed that the inspection temperature of the semiconductor device on the semiconductor wafer deviates from the set temperature of the wafer chuck by, for example, up to about 10°C.

[0008] Specifically, it was found that when the set temperature of the wafer chuck is 125°C, the inspection temperature of the semiconductor device can drop to about 115°C. On the other hand, when the set temperature of the wafer chuck is -40°C, the inspection temperature of the semiconductor device can rise to about -30°C. Heat is transferred via probes (not particularly limited, but for example, several thousand probes) that are in contact with the semiconductor device, and it is thought that one of the reasons for this is that the amount of heat transfer becomes unstable due to various factors.

[0009] However, due to various factors, it is difficult to match the probe temperature with the set temperature of the wafer chuck during testing, so it is necessary to test the temperature characteristics of the bandgap reference circuit with higher accuracy in an environment where the testing temperature of the semiconductor device is not accurately known.

[0010] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. The present disclosure is not limited to semiconductor devices used in automotive electronic systems, and various other factors may be considered as causes of variations in the test temperature of semiconductor devices, in addition to heat transfer via a probe in contact with the semiconductor device. [Means for solving the problem]

[0011] According to one embodiment, before the temperature characteristics of the bandgap reference circuit are tested, the temperature dependencies of the reference voltage and the absolute temperature proportional voltage are measured in advance for a plurality of samples. When the temperature characteristics are tested, the difference between the absolute temperature proportional voltage of the bandgap reference circuit at a predetermined temperature and the median of the absolute temperature proportional voltages of the plurality of samples is calculated based on the difference between the reference voltage of the bandgap reference circuit at a predetermined temperature and the median of the reference voltages of the plurality of samples. [Effects of the Invention]

[0012] According to the embodiment, it is possible to provide a semiconductor device that can test the temperature characteristics of a bandgap reference circuit with higher accuracy in an environment where the test temperature of the semiconductor device is not accurately known. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram of a semiconductor device according to the first embodiment. [Figure 2] FIG. 2 is a circuit diagram showing an example of the circuit configuration of the bandgap reference circuit BGR1. [Figure 3] FIG. 3 is a graph showing the temperature dependence of the reference voltage Vref1, the absolute temperature proportional voltage Vptat1, and the base-emitter voltage Vbe2 of the bipolar transistor BT2 shown in FIG. [Figure 4] FIG. 4 is a graph showing the results of a simulation of variations in the reference voltage Vref1 due to manufacturing variations and the like. [Figure 5]FIG. 5 is a graph showing the results of a simulation of variations in the temperature dependency of the absolute temperature proportional voltage Vptat1 due to manufacturing variations and the like. [Figure 6] FIG. 6 is a graph showing the temperature dependency of the reference voltage Vref1. [Figure 7] FIG. 7 is a graph showing the temperature dependency of the absolute temperature proportional voltage Vptat1. [Figure 8] FIG. 8 is a graph showing the temperature dependency of the reference voltage Vref1. [Figure 9] FIG. 9 is a graph showing the temperature dependency of the absolute temperature proportional voltage Vptat1. [Figure 10] FIG. 10 is a block diagram of a semiconductor device according to the second embodiment. [Figure 11] FIG. 11 is a circuit diagram showing an example of the circuit configuration of the temperature sensor modules THS1 and THS2. [Figure 12] FIG. 12 is a circuit diagram showing an example of the circuit configuration of the temperature sensor modules THS1 and THS2. [Figure 13] FIG. 13 is a circuit diagram showing an example of the circuit configuration of the temperature sensor modules THS1 and THS2. [Figure 14] FIG. 14 is a circuit diagram showing an example of the circuit configuration of the temperature sensor modules THS1 and THS2. [Figure 15] FIG. 15 is a graph showing a schematic diagram of aged deterioration in the temperature sensor module THS1. [Figure 16] FIG. 16 is a graph showing a schematic diagram of aged deterioration in the temperature sensor module THS1. DETAILED DESCRIPTION OF THE INVENTION

[0014] For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. Furthermore, each element shown in the drawings as a functional block performing various processes can be configured in hardware with a CPU, memory, and other circuits, and in software with a program loaded into memory, etc. Therefore, those skilled in the art will understand that these functional blocks can be realized in various forms using only hardware, only software, or a combination thereof, and are not limited to any one of these. In addition, the same elements are designated by the same reference numerals in each drawing, and redundant explanations are omitted as necessary.

[0015] (First embodiment) <Configuration of semiconductor device> First, a semiconductor device according to a first embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram of the semiconductor device according to the first embodiment. 1, the semiconductor device 100 according to the first embodiment is, for example, an IC chip, and includes a bandgap reference circuit BGR1. As shown in FIG. 1, the bandgap reference circuit BGR1 outputs a reference voltage Vref1 and an absolute temperature proportional voltage Vptat1.

[0016] The reference voltage Vref1 is constant with respect to temperature within a predetermined temperature range. Here, "constant" naturally has a certain tolerance and does not necessarily have to be completely constant. The reference voltage Vref1 is an analog voltage signal and is output to the outside of the semiconductor device 100 via the external terminal T1.

[0017] On the other hand, the absolute temperature proportional voltage Vptat1 is proportional to the absolute temperature. The absolute temperature proportional voltage Vptat1 is an analog voltage signal, and is output to the outside of the semiconductor device 100 via the external terminal T2.

[0018] In this way, the bandgap reference circuit BGR1 is a reference voltage generation circuit that generates a constant reference voltage Vref1 relative to temperature. Furthermore, since the bandgap reference circuit BGR1 generates a voltage Vptat1 proportional to absolute temperature, it also functions as a temperature sensor that can detect temperature.

[0019] Here, Figure 2 is a circuit diagram showing an example of the circuit configuration of the bandgap reference circuit BGR1. The bandgap reference circuit BGR1 shown in Figure 2 is a bandgap reference circuit called a Brokaw cell. The bandgap reference circuit BGR1 shown in FIG. 2 includes resistors R1 to R4, bipolar transistors BT1 and BT2, and an amplifier AMP.

[0020] As shown in Figure 2, one end of resistors R1 and R2 is connected to the power supply VCC. Resistors R1 and R2 have the same resistance. The other end of resistor R1 is connected to the collector of bipolar transistor BT1, and the other end of resistor R2 is connected to the collector of bipolar transistor BT2. The emitter of bipolar transistor BT1 is connected to one end of resistor R3, and the other end of resistor R3 is connected to one end of resistor R4. The emitter of bipolar transistor BT2 is connected to the node between resistors R3 and R4. The other end of resistor R4 is grounded.

[0021] As shown in Figure 2, the inverting (-) input terminal of amplifier AMP is connected to the node between resistor R1 and the collector of bipolar transistor BT1, while the non-inverting (+) input terminal of amplifier AMP is connected to the node between resistor R2 and the collector of bipolar transistor BT2.

[0022] The output terminal of the amplifier AMP outputs a reference voltage Vref1 and is connected in common to the bases of the bipolar transistors BT1 and BT2. The negative feedback loop of the amplifier AMP controls the collector currents of the bipolar transistors BT1 and BT2 so that they are equal. An analog buffer circuit such as a voltage follower may be provided between the output terminal of the amplifier AMP and the external terminal T1 that outputs the reference voltage Vref1 to the outside.

[0023] As shown in FIG. 2, the voltage across resistor R4 is an absolute temperature proportional voltage Vptat1, which is output from the node between resistors R3 and R4. An analog buffer circuit such as a voltage follower may be provided between the node and an external terminal T2 that outputs the absolute temperature proportional voltage Vptat1 to the outside.

[0024] The relationship between the reference voltage Vref1 and the absolute temperature proportional voltage Vptat1 is shown in Figure 2. As shown in Figure 2, if the base-emitter voltage of the bipolar transistor BT2 is Vbe2, then Vref1 = Vbe2 + Vptat1 holds. If the base-emitter voltage of bipolar transistor BT1 is Vbe1, the difference ΔVbe between the base-emitter voltages Vbe1 and Vbe2 of bipolar transistors BT1 and BT2 is expressed as ΔVbe=Vbe2-Vbe1. As shown in Figure 2, ΔVbe is equal to the voltage across resistor R3.

[0025] 2 is merely one example of the configuration of the bandgap reference circuit BGR1. The configuration of the bandgap reference circuit BGR1 is not limited to the circuit shown in FIG. 2. The configuration of the bandgap reference circuit BGR1 is not limited in any way as long as it can output a reference voltage Vref1 that is constant with respect to temperature within a predetermined temperature range and an absolute temperature proportional voltage Vptat1 that is proportional to absolute temperature.

[0026] FIG. 3 is a graph showing the temperature dependence of the reference voltage Vref1, the absolute temperature proportional voltage Vptat1, and the base-emitter voltage Vbe2 of the bipolar transistor BT2. In FIG. 3, the horizontal axis represents temperature (°C) and the vertical axis represents voltage. As shown in FIGS. 2 and 3, Vref1 ≒ Vbe2 + Vptat1 holds. When the collector currents of bipolar transistors BT1 and BT2 are the same, Vref1 = Vbe2 + Vptat1 holds true, but in some circuit designs, the collector currents of bipolar transistors BT1 and BT2 are intentionally shifted. For this reason, in Figure 3, Vref1 ≒ Vbe2 + Vptat1 is written.

[0027] As shown in Figure 3, the absolute temperature proportional voltage Vptat1 has a positive temperature dependency. On the other hand, the base-emitter voltage Vbe2 of bipolar transistor BT2 has a negative temperature dependency. The absolute temperature proportional voltage Vptat1 and the base-emitter voltage Vbe2 of bipolar transistor BT2 cancel each other out, resulting in a constant reference voltage Vref1 with respect to temperature within a specified temperature range. For example, in the bandgap reference circuit BGR1 shown in Figure 2, the ratio of resistors R3 and R4 and the transistor ratio of bipolar transistors BT1 and BT2 are adjusted to obtain this reference voltage Vref1. The predetermined temperature range is, for example, a temperature range in which the semiconductor device 100 is guaranteed to operate (for example, −40 to 125° C.).

[0028] As described above, the bandgap reference circuit BGR1 has variations in temperature characteristics due to, for example, manufacturing variations, etc. Therefore, when manufacturing the semiconductor device 100, the temperature characteristics of the bandgap reference circuit BGR1 are inspected so that the temperature can be accurately measured within the temperature range in which operation is guaranteed.

[0029] In the semiconductor device 100 according to this embodiment, before the temperature characteristics of the bandgap reference circuit BGR1 are inspected, the temperature dependence of the reference voltage Vref1 and the voltage proportional to absolute temperature Vptat1 is measured in advance for a plurality of samples. For example, each sample is placed in a thermostatic chamber, and the reference voltage Vref1 and the voltage proportional to absolute temperature Vptat1 are measured at each temperature with a temperature error of ±1°C or less. The number of samples is, for example, 100 or more. More specifically, the number of samples is in the range of several hundred to several thousand.

[0030] 4 is a graph showing the results of a simulation of variations in the temperature dependency of the reference voltage Vref1 due to manufacturing variations, etc. In FIG. 4, the horizontal axis represents temperature (°C) and the vertical axis represents the reference voltage Vref1 (V). In FIG. 4, the median value Vref_m of the reference voltage Vref1 of all samples is also shown by a dashed line.

[0031] As shown in Fig. 4, the median value Vref_m of the reference voltage is approximately 1.23 to 1.25 V at temperatures between -40 and 125°C, and increases by approximately 20 mV (0.02 V) as the temperature rises, but remains approximately constant with respect to temperature. Also, as shown in Fig. 4, the variation range of the reference voltage Vref1 is approximately constant at approximately 30 mV (0.03 V) at temperatures between -40 and 125°C.

[0032] Figure 5 is a graph showing the results of a simulation of the variation in the temperature dependency of the absolute temperature proportional voltage Vptat1 due to manufacturing variations, etc. In Figure 5, the horizontal axis represents temperature (°C) and the vertical axis represents the absolute temperature proportional voltage Vptat1 (V). Figure 5 also shows the median value Vref_m of the absolute temperature proportional voltage Vptat1 of all samples with a dashed line.

[0033] 5, the voltage Vptat1 proportional to absolute temperature has a linear relationship with temperature at a slope of approximately 1.3 to 1.6 mV / ° C. in the range of −40 to 125° C. Also, as shown in FIG. 5, the variation width of the voltage Vptat1 proportional to absolute temperature is approximately constant at approximately 30 mV (0.03 V) in the range of −40 to 125° C.

[0034] 4 and 5, let us focus on the curve and line of a certain sample. Let ΔVref1 be the difference between the reference voltage Vref1 of that sample at a certain temperature and the median Vref_m of the reference voltages of all samples. Let ΔVptat1 be the difference between the absolute temperature proportional voltage Vptat1 of that sample at that temperature and the median Vptat_m of the absolute temperature proportional voltages of all samples.

[0035] The inventors have found that the ratio ΔVptat1 / ΔVref1 between the two is substantially constant regardless of temperature and is substantially the same value regardless of the sample. In this specification, the term "median" includes not only the strict definition of the median but also the mean value. Furthermore, since the variations in the reference voltage Vref1 and the absolute temperature proportional voltage Vptat1 are normally distributed, the mean value and the strict definition of the median are approximately the same.

[0036] In the semiconductor device 100 according to this embodiment, the temperature characteristics of the bandgap reference circuit BGR1 are inspected by utilizing the variation characteristics of the reference voltage Vref1 and the absolute temperature proportional voltage Vptat1. Specifically, ΔVptat1, which indicates the temperature characteristics, is calculated based on ΔVref1, which has a small temperature change, and the temperature characteristics are inspected.

[0037] Therefore, in the semiconductor device 100 according to this embodiment, even in an environment where the test temperature is not accurately known, the temperature characteristics of the bandgap reference circuit BGR1 can be tested with higher accuracy. A method for testing the temperature characteristics of the bandgap reference circuit BGR1 will be described below.

[0038] <Temperature characteristics inspection method> Next, a method for inspecting the temperature characteristics of the bandgap reference circuit BGR1 will be described with reference to FIGS. Figure 6 is a graph showing the temperature dependence of the reference voltage Vref1. In Figure 6, the horizontal axis represents temperature T (°C) and the vertical axis represents reference voltage Vref1 (V). In Figure 6, the reference voltage Vref1 of the bandgap reference circuit BGR1 under test is shown by a solid line, and the median value Vref_m of the reference voltages of multiple samples measured in advance is shown by a dashed line.

[0039] Figure 7 is a graph showing the temperature dependence of the absolute temperature proportional voltage Vptat1. In Figure 7, the horizontal axis represents temperature T (°C) and the vertical axis represents the absolute temperature proportional voltage Vptat1 (V). In Figure 7, the absolute temperature proportional voltage Vptat1 of the bandgap reference circuit BGR1 under test is shown by a solid line, and the median value Vptat_m of the absolute temperature proportional voltages of multiple samples measured in advance is shown by a dashed dotted line.

[0040] 6 and 7 show how the test temperature is set to −40° C., which is the lower limit temperature at which the semiconductor device 100 is guaranteed to operate, and the reference voltage Vref1 and the absolute temperature proportional voltage Vptat1 are measured. First, as shown in Figure 6, the set temperature for the test is -40°C, but the reference voltage Vref1(Tm) is actually measured at a measurement temperature Tm [°C]. That is, the measurement temperature Tm [°C] is near -40°C, but is unknown. As shown in Figure 6, the measurement temperature Tm [°C] is likely to be higher than -40°C, for example, around -30°C.

[0041] As shown in FIG. 6, the reference voltage Vref1 and the median value Vref_m of the reference voltage are substantially constant with respect to temperature. Therefore, the median value Vref_m (-40) of the reference voltage at -40°C is substantially the same as the median value Vref_m of the reference voltage at the measurement temperature Tm [°C]. Therefore, the difference ΔVref1 between the reference voltage Vref1 and the median value Vref_m of the reference voltage is substantially equal to the difference ΔVref1' between the reference voltage Vref1 (Tm) at the measurement temperature Tm [°C] and the median value Vref_m (-40) of the reference voltage at -40°C. Also, referring to FIG. 3, the change in Vref1 between -40°C and Tm [°C] is negligibly small compared to the change in Vptat1. That is, since the calculated ΔVref1′≈ΔVref1 holds, it is assumed that the calculated ΔVref1′=ΔVref1.

[0042] Next, as shown in Fig. 7, the difference ΔVptat1 between the absolute temperature proportional voltage Vptat1(Tm) at the measurement temperature Tm [°C] and the median value Vptat_m of the absolute temperature proportional voltages is calculated using the above-mentioned relationship ΔVptat1 / ΔVref1 = constant. For example, if ΔVptat1 / ΔVref1 = 1.0, then ΔVptat1 = ΔVref1. The calculated ΔVptat1 is an inherent value that indicates the temperature characteristic of each bandgap reference circuit BGR1.

[0043] As shown in FIG. 7, the absolute temperature proportional voltage Vptat1=Vptat_m+ΔVptat1 holds, and therefore the calculated ΔVptat1 is substituted to obtain the temperature characteristic formula of the absolute temperature proportional voltage Vptat1. As will be described in detail later, the calculated ΔVptat1 is converted into a digital signal and stored in a storage unit such as a fuse bit of a controller that controls the bandgap reference circuit BGR1, for example.

[0044] Furthermore, as shown in FIG. 7, by subtracting the calculated ΔVptat1 from the absolute temperature proportional voltage Vptat1(Tm) at the measurement temperature Tm [° C.], the median value Vptat_m(Tm) of the absolute temperature proportional voltage at the measurement temperature Tm [° C.] is obtained. 7, the median value Vptat_m of the absolute temperature proportional voltage is known and expressed as Vptat_m = α × T + β using constants α and β. For example, the constant α, which indicates the slope of the line, is approximately 1.5 [mV / °C], and the constant β is approximately 400 [mV]. That is, since Vptat_m(Tm)=α×Tm+β, the measured temperature Tm [° C.] can be obtained from Tm={Vptat_m(Tm)−β} / α.

[0045] As described above, when testing the temperature characteristics of the bandgap reference circuit BGR1, the inventors use the constant relationship of ΔVptat1 / ΔVref1 to calculate ΔVptat1, which indicates the temperature characteristics, based on ΔVref1, which has a small temperature change. The calculated ΔVptat1 is then used to correct the absolute temperature proportional voltage Vptat1 of the bandgap reference circuit BGR1.

[0046] In FIG. 7, if the difference between the absolute temperature proportional voltage Vptat1(Tm) at the measurement temperature Tm [° C.] and the absolute temperature proportional voltage Vptat1(-40) at -40° C. is taken as ΔVptat1, it will be larger than the actual value.

[0047] In contrast, in the semiconductor device 100 according to this embodiment, when testing the temperature characteristics, ΔVptat1 indicating the temperature characteristics is calculated based on ΔVref1, which has a small temperature change as shown in Fig. 6. Therefore, even in an environment where the test temperature is not accurately known, the temperature characteristics of the bandgap reference circuit BGR1 can be tested with higher accuracy.

[0048] Next, a method for inspecting the temperature characteristics of the bandgap reference circuit BGR1 will be described with reference to FIGS. Fig. 8 is a graph showing the temperature dependence of the reference voltage Vref1. Fig. 9 is a graph showing the temperature dependence of the absolute temperature proportional voltage Vptat1. The graphs shown in Fig. 8 and Fig. 9 are the same as the graphs shown in Fig. 6 and Fig. 7, respectively.

[0049] However, FIGS. 8 and 9 show how the test temperature is set to 125° C., which is the upper limit temperature at which the semiconductor device 100 is guaranteed to operate, and the reference voltage Vref1 and the absolute temperature proportional voltage Vptat1 are measured. First, as shown in Figure 8, it is assumed that the set temperature for the test is 125°C, but the reference voltage Vref1(Tm) is actually measured at a measurement temperature Tm [°C]. That is, the measurement temperature Tm [°C] is close to 125°C, but is unknown. As shown in Figure 8, the measurement temperature Tm [°C] is likely to be lower than 125°C, for example, around 115°C.

[0050] As shown in FIG. 8, the reference voltage Vref1 and the median value Vref_m of the reference voltage are substantially constant with respect to temperature. Therefore, the median value Vref_m(125) of the reference voltage at 125°C is substantially the same as the median value Vref_m of the reference voltage at the measurement temperature Tm [°C]. Therefore, the difference ΔVref1 between the reference voltage Vref1 and the median value Vref_m of the reference voltage is substantially equal to the difference ΔVref1' between the reference voltage Vref1(Tm) at the measurement temperature Tm [°C] and the median value Vref_m(125) of the reference voltage at 125°C. Also, referring to FIG. 3, the change in Vref1 between 125°C and Tm [°C] is negligibly small compared to the change in Vptat1. That is, since the calculated ΔVref1′≈ΔVref1 holds, it is assumed that the calculated ΔVref1′=ΔVref1.

[0051] Next, as shown in Fig. 9, the difference ΔVptat1 between the absolute temperature proportional voltage Vptat1(Tm) at the measurement temperature Tm [°C] and the median value Vptat_m of the absolute temperature proportional voltages is calculated using the relationship ΔVptat1 / ΔVref1 = constant. For example, if ΔVptat1 / ΔVref1 = 1.0, then ΔVptat1 = ΔVref1. The calculated ΔVptat1 is an inherent value that indicates the temperature characteristic of the bandgap reference circuit BGR1.

[0052] As shown in FIG. 9, the absolute temperature proportional voltage Vptat1=Vptat_m+ΔVptat1 holds, and therefore the calculated ΔVptat1 is substituted to obtain the temperature characteristic equation of the absolute temperature proportional voltage Vptat1. As will be described in detail later, the calculated ΔVptat1 is converted into a digital signal and stored in a storage unit such as a fuse bit of a controller that controls the bandgap reference circuit BGR1, for example.

[0053] Furthermore, as shown in FIG. 9, by subtracting ΔVptat1 from the absolute temperature proportional voltage Vptat1(Tm) at the measurement temperature Tm [° C.], the median value Vptat_m(Tm) of the absolute temperature proportional voltage at the measurement temperature Tm [° C.] is obtained. 9, the median value Vptat_m of the absolute temperature proportional voltage is expressed as Vptat_m=α×T+β using constants α and β. That is, since Vptat_m(Tm)=α×Tm+β, the measured temperature Tm [°C] can be obtained from Tm={Vptat_m(Tm)-β} / α.

[0054] As described above, when testing the temperature characteristics of the bandgap reference circuit BGR1, the inventors use the constant relationship of ΔVptat1 / ΔVref1 to calculate ΔVptat1, which indicates the temperature characteristics, based on ΔVref1, which has a small temperature change. The calculated ΔVptat1 is then used to correct the absolute temperature proportional voltage Vptat1 of the bandgap reference circuit BGR1.

[0055] In FIG. 9, if the difference between the absolute temperature proportional voltage Vptat1(Tm) at the measurement temperature Tm [° C.] and the absolute temperature proportional voltage Vptat1(125) at 125° C. is taken as ΔVptat1, it will be smaller than the actual value.

[0056] In contrast, in the semiconductor device 100 according to this embodiment, when testing the temperature characteristics, ΔVptat1 indicating the temperature characteristics is calculated based on ΔVref1, which has a small temperature change as shown in Fig. 8. Therefore, even in an environment where the test temperature is not accurately known, the temperature characteristics of the bandgap reference circuit BGR1 can be tested with higher accuracy.

[0057] As shown in Figure 6, when the measured temperature Tm [°C] is near -40°C, the measured temperature Tm [°C] is likely to be higher than -40°C. In that case, as shown in Figure 6, the calculated ΔVref1' is larger than the actual ΔVref1. As a result, the calculated value of ΔVptat1 is also larger than the actual value.

[0058] On the other hand, as shown in Figure 8, when the measured temperature Tm [°C] is near 125°C, the measured temperature Tm [°C] is likely to be lower than 125°C. In that case, as shown in Figure 8, the calculated ΔVref1' is smaller than the actual ΔVref1. As a result, the calculated value of ΔVptat1 is also smaller than the actual value.

[0059] Therefore, when calculating ΔVptat1, it is preferable to use the average of ΔVref1 obtained when the measurement temperature Tm [°C] is both near -40°C and near 125°C. This makes it possible to bring the calculated value of the difference ΔVref1 between the reference voltage Vref1 and the median value Vref_m of the reference voltage closer to the actual value.

[0060] (Second embodiment) <Configuration of semiconductor device> Next, a semiconductor device according to a second embodiment will be described with reference to Fig. 10. Fig. 10 is a block diagram of the semiconductor device according to the second embodiment. As shown in FIG. 10, a semiconductor device 200 according to the second embodiment is, for example, an IC chip, and includes temperature sensor modules THS1 to THS4.

[0061] As shown in Fig. 10, the temperature sensor module THS1 includes the bandgap reference circuit BGR1 shown in Fig. 1. Similar to the semiconductor device 100 according to the first embodiment shown in Fig. 1, the bandgap reference circuit BGR1 outputs a reference voltage Vref1 to an external terminal T1 and also outputs an absolute temperature proportional voltage Vptat1 to an external terminal T2. As shown in FIG. 10, the temperature sensor modules THS2 to THS4 also include bandgap reference circuits BGR2 to BGR4, respectively.

[0062] As shown in FIG. 10, the temperature sensor modules THS1 and THS2 are formed in the same power supply domain PD1. The temperature sensor module THS3 is formed in the power supply domain PD2. The power supply domain PD2 is an area with a different power supply voltage from that of the power supply domain PD1. The power supply domain PD2 is surrounded by a power supply isolation cell PIC1, and the power supply of the power supply domain PD2 is isolated from that of the power supply domain PD1. The temperature sensor module THS4 is formed in the power supply domain PD3. The power supply domain PD3 is an area where the power supply voltage is cut off during a low power consumption mode (e.g., sleep mode). The power supply domain PD3 is surrounded by a power supply isolation cell PIC2, ​​and the power supply is isolated from the power supply domain PD1.

[0063] The power supply domains PD2 and PD3 are not essential, and only one of the power supply domains PD2 and PD3 may be provided. Furthermore, the number of temperature sensor modules is not limited as long as it is plural.

[0064] Here, the temperature characteristics of the temperature sensor module THS1 have been inspected by the temperature characteristics inspection method described in the first embodiment. As shown in Fig. 10, the temperature sensor module THS1 after the temperature characteristics inspection outputs reference voltages Vrl1 and Vrh1. The reference voltages Vrl1 and Vrh1 are input to the temperature sensor modules THS2 to THS4, respectively.

[0065] As will be described in detail later, the reference voltages Vrl1 and Vrh1 are generated from the reference voltage Vref1 in the temperature sensor module THS1, which has undergone a temperature characteristics test. The temperature sensor modules THS2 to THS4 can test the temperature characteristics of the bandgap reference circuits BGR2 to BGR4 based on the reference voltages Vrl1 and Vrh1, respectively.

[0066] <Detailed circuit configuration of semiconductor device> Next, a detailed circuit configuration of the semiconductor device 200 according to this embodiment will be described with reference to Fig. 11. Fig. 11 is a circuit diagram showing an example of the circuit configuration of the temperature sensor modules THS1 and THS2.

[0067] First, the temperature sensor module THS1 will be described. As shown in FIG. 11, the temperature sensor module THS1 includes a bandgap reference circuit BGR1, selectors SLa1, SLb1, an A / D converter ADC1, and a controller CTR1.

[0068] The bandgap reference circuit BGR1 is the same as the bandgap reference circuit BGR1 according to the first embodiment shown in FIGS. 1 and 2. As shown in FIG. 11, the bandgap reference circuit BGR1 outputs a reference voltage Vref1 to an external terminal T1 and outputs an absolute temperature proportional voltage Vptat1 to an external terminal T2.

[0069] As shown in FIG. 11, a plurality of reference voltages (reference divided voltages) Vrl1, Vrm11, Vrm12, Vrh1 (Vrl1 < Vrm11 < Vrm12 < Vrh1) obtained by dividing the reference voltage Vref1 by a ladder resistor are generated. Here, the reference voltage Vrl1 is a voltage at the same level as the absolute temperature proportional voltage Vptat1 at the lower limit temperature (-40° C. for example) for ensuring the operation of the semiconductor device 200. The reference voltage Vrh1 is a voltage at the same level as the absolute temperature proportional voltage Vptat1 at the upper limit temperature (125° C. for example) for ensuring the operation of the semiconductor device 200.

[0070] The reference voltages Vrm11, Vrm12 (Vrm12 > Vrm11) are voltages at the same level as the absolute temperature proportional voltage Vptat1 at a predetermined temperature higher than the lower limit temperature for ensuring the operation of the semiconductor device 200 and lower than the upper limit temperature. Note that the reference voltages Vrm11, Vrm12 are not essential. The number of reference voltages between the reference voltage Vrl1 and the reference voltage Vrh1 is not limited to two of the reference voltages Vrm11, Vrm12, and may be one or three or more.

[0071] As shown in FIG. 11, the absolute temperature proportional voltage Vptat1 and the reference voltages Vrl1, Vrm11, Vrm12, Vrh1 are input to the selector SLa1. The selector SLa1 selects one of the input voltage signals based on a selection control signal sca1 output from the controller CTR1.

[0072] The selector SLb1 receives a reference voltage Vref1 as input, and selects the reference voltage Vref1 based on a selection control signal scb1 output from the controller CTR1. 11, only the reference voltage Vref1 is input to the selector SLb1, but in reality, other signals (not shown) are also input, which is why the selector SLb1 is provided.

[0073] The A / D converter ADC1 receives an analog voltage signal of the absolute temperature proportional voltage Vptat1 and one of the reference voltages Vrl1, Vrm11, Vrm12, and Vrh1 via a selector SLa1. Furthermore, a reference voltage Vref1, which is an analog voltage signal, is input to the A / D converter ADC1 via a selector SLb1.

[0074] The A / D converter ADC1 converts the voltage signal input via the selector SLa1 into a digital voltage signal Vd1 using the reference voltage Vref1 input via the selector SLb1 as a reference signal. That is, the digital voltage signal Vd1 includes digital signals obtained by A / D conversion of the absolute temperature proportional voltage Vptat1 and the reference voltages Vrl1, Vrm11, Vrm12, and Vrh1. The digital voltage signal Vd1 output from the A / D converter ADC1 is stored in the fuse bit FB1 of the controller CTR1.

[0075] The controller CTR1 controls the temperature sensor module THS1. Specifically, as shown in Fig. 11, the controller CTR1 outputs selection control signals sca1 and scb1 to selectors SLa1 and SLb1, respectively. The controller CTR1 also includes a fuse bit FB1 that stores the digital voltage signal Vd1 output from the A / D converter ADC1.

[0076] 11, the controller CTR1 may be connected to a controller CTR2 of the temperature sensor module THS2, so that the controllers CTR1 and CTR2 may be able to transmit and receive data stored in the fuse bits FB1 and FB2 to and from each other. The controller CTR1 may be provided outside the temperature sensor module THS1, and the fuse bit FB1 may be provided outside the controller CTR1.

[0077] Here, the temperature characteristics of the temperature sensor module THS1 are inspected by the temperature characteristics inspection method described in the first embodiment. 11, in the semiconductor device 200 according to this embodiment, the temperature sensor module THS1, which has undergone a temperature characteristic test, outputs reference voltages Vrl1 and Vrh1. The reference voltages Vrl1 and Vrh1 are input to the temperature sensor modules THS2 to THS4, respectively. As will be described in detail later, the temperature sensor modules THS2 to THS4 can test the temperature characteristics of the bandgap reference circuits BGR2 to BGR4 based on the reference voltages Vrl1 and Vrh1, respectively.

[0078] Next, the temperature sensor module THS2 will be described. The temperature sensor module THS2 has the same circuit configuration as the temperature sensor module THS1. Specifically, the temperature sensor module THS2 includes a bandgap reference circuit BGR2, selectors SLa2 and SLb2, an A / D converter ADC2, and a controller CTR2. The temperature sensor modules THS3 and THS4 have the same circuit configuration as the temperature sensor module THS2 and operate in the same manner, so a description thereof will be omitted.

[0079] Like the bandgap reference circuit BGR1 according to the first embodiment shown in FIGS. 1 and 2, the bandgap reference circuit BGR2 outputs a reference voltage Vref2 and also outputs a voltage Vptat2 proportional to absolute temperature. On the other hand, as shown in FIG. 11, no external terminals are provided for externally outputting the reference voltage Vref2 and the absolute temperature proportional voltage Vptat2 output by the bandgap reference circuit BGR2. With such a configuration, the number of external terminals can be reduced.

[0080] As shown in FIG. 11, a plurality of reference voltages (reference divided voltages) Vrl2, Vrm21, Vrm22, Vrh2 (Vrl2 < Vrm21 < Vrm22 < Vrh2) obtained by dividing the reference voltage Vref2 by a ladder resistor are generated. Here, the reference voltage Vrl2 is a voltage at the same level as the absolute temperature proportional voltage Vptat2 at the lower limit temperature (-40° C., for example) for ensuring the operation of the semiconductor device 200. The reference voltage Vrh2 is a voltage at the same level as the absolute temperature proportional voltage Vptat2 at the upper limit temperature (125° C., for example) for ensuring the operation of the semiconductor device 200. The reference voltages Vrm21, Vrm22 (Vrm22 > Vrm21) are voltages at the same level as the absolute temperature proportional voltage Vptat2 at a predetermined temperature higher than the lower limit temperature and lower than the upper limit temperature for ensuring the operation of the semiconductor device 200, respectively.

[0081] As shown in FIG. 11, the absolute temperature proportional voltage Vptat2 and the reference voltages Vrl1, Vrm11, Vrm12, Vrh1 are input to the selector SLa2 in the same manner as the selector SLa1. Further, the reference voltage Vref2 is also input to the selector SLa2. The selector SLa2 selects one of the input voltage signals based on the selection control signal sca2 output from the controller CTR2.

[0082] The reference voltage Vref1 is input to the selector SLb2 in the same manner as the selector SLb1. Further, the reference voltages Vrl1, Vrh1 output from the temperature sensor module THS1 are also input to the selector SLb2. The selector SLb2 selects one of the input voltage signals based on the selection control signal scb2 output from the controller CTR2.

[0083] An analog voltage signal of the absolute temperature proportional voltage Vptat2 and one of the reference voltages Vref2, Vrl2, Vrm21, Vrm22, and Vrh2 is input to the A / D converter ADC2 via a selector SLa2. Furthermore, an analog voltage signal of one of the reference voltages Vref2, Vrl1, and Vrh1 is input to the A / D converter ADC2 via a selector SLb2.

[0084] The A / D converter ADC2 uses the reference voltage Vref2 input via the selector SLb2 as a reference signal to convert the absolute temperature proportional voltage Vptat2 and the reference voltages Vrl2, Vrm21, Vrm22, and Vrh2 input via the selector SLa2 into a digital voltage signal Vd1. That is, the digital voltage signal Vd2 includes digital signals obtained by A / D converting the absolute temperature proportional voltage Vptat2 and the reference voltages Vrl2, Vrm21, Vrm22, and Vrh2.

[0085] On the other hand, the A / D converter ADC2 also converts the reference voltages Vrl1 and Vrh1 input via the selector SLb2 into a digital voltage signal Vd1, using the reference voltage Vref2 input via the selector SLa2 as a reference signal. That is, the digital voltage signal Vd2 also includes digital signals obtained by A / D converting the reference voltages Vrl1 and Vrh1. The digital voltage signal Vd2 output from the A / D converter ADC2 is stored in the fuse bit FB2 of the controller CTR2.

[0086] The controller CTR2 controls the temperature sensor module THS2. Specifically, as shown in Fig. 11, the controller CTR2 outputs selection control signals sca2 and scb2 to the selectors SLa2 and SLb2, respectively. The controller CTR2 also includes a fuse bit FB2 that stores the digital voltage signal Vd2 output from the A / D converter ADC2.

[0087] Here, the temperature characteristics of the temperature sensor module THS1 are inspected by the temperature characteristics inspection method described in the first embodiment. 11, in the semiconductor device 200 according to this embodiment, the temperature sensor module THS1, which has undergone a temperature characteristic test, outputs reference voltages Vrl1 and Vrh1. The reference voltages Vrl1 and Vrh1 are input to the temperature sensor module THS2. The temperature sensor module THS2 can test the temperature characteristics of the bandgap reference circuit BGR2 based on the reference voltages Vrl1 and Vrh1. A method for testing the temperature characteristics of the bandgap reference circuit BGR2 will be described below.

[0088] <Temperature characteristics inspection method> Next, a method for inspecting the temperature characteristics of the bandgap reference circuit BGR2 will be described with reference to Fig. 12. Fig. 12 is a circuit diagram showing an example of the circuit configuration of the temperature sensor modules THS1 and THS2. Fig. 12 shows only the signals used to inspect the temperature characteristics of the bandgap reference circuit BGR2, out of the signals shown in Fig. 11.

[0089] 12, the reference voltages Vrl1 and Vrh1 output from the temperature sensor module THS1 that has undergone a temperature characteristics test are input to the temperature sensor module THS2. In the temperature sensor module THS2, the reference voltages Vrl1 and Vrh1 are input to the A / D converter ADC2 via the selector SLb2.

[0090] The reference voltages Vrl1 and Vrh1 are converted into a digital voltage signal Vd2 in an A / D converter ADC2 using a reference voltage Vref2 input via a selector SLa2 as a reference signal. The digital voltage signal Vd2 is stored in a fuse bit FB2. Here, the digital voltage signals of the reference voltages Vrl1 and Vrh1 that are A / D converted using the reference voltage Vref2 as a reference signal are designated as D_ref2_rl1 and D_ref2_rh1 (not shown).

[0091] The reference voltages Vrl1 and Vrh1 are converted into a digital voltage signal Vd1 by an A / D converter ADC1 in the temperature sensor module THS1 using a reference voltage Vref1 input via a selector SLb1 as a reference signal. The digital voltage signal Vd1 is stored in a fuse bit FB1. Here, the digital voltage signals of the reference voltages Vrl1 and Vrh1 that are A / D converted using the reference voltage Vref1 as a reference signal are designated as D_ref1_rl1 and D_ref1_rh1 (not shown).

[0092] As shown in FIG. 6, the difference between the reference voltage Vref1 and the median value Vref_m of the reference voltage is denoted as ΔVref1, and similarly the difference between the reference voltage Vref2 and the median value Vref_m of the reference voltage is denoted as ΔVref2.

[0093] The difference between the digital voltage signal D_ref2_rl1 of the reference voltage Vrl1 based on the reference voltage Vref2 and the digital voltage signal D_ref1_rl1 of the reference voltage Vrl1 based on the reference voltage Vref1 is the common reference voltage Vrl1. Therefore, the following equation (1) holds: D_ref2_rl1-D_ref1_rl1=D_Δref2-D_Δref1 ···(1)

[0094] In equation (1), D_Δref2 is the digital value of ΔVref2, and D_Δref1 is the digital value of ΔVref1. That is, the right side of equation (1) is the digital value of ΔVref2−ΔVref1. Therefore, the following equation (2) holds true. ΔVref2-ΔVref1≒D_ref2_rl1-D_ref1_rl1 ···(2) Since ΔVref1 is known, ΔVref2 can be obtained by modifying equation (2). ΔVref2≒D_ref2_rl1-D_ref1_rl1+ΔVref1

[0095] Here, the difference between the absolute temperature proportional voltage Vptat2 output by the bandgap reference circuit BGR2 and the median value Vptat_m of the absolute temperature proportional voltages is defined as ΔVptat2. As explained in the first embodiment, ΔVptat2, which is an intrinsic value indicating the temperature characteristic of the bandgap reference circuit BGR2, is obtained from the constant relationship ΔVptat2 / ΔVref2. In this way, the temperature characteristics of the bandgap reference circuit BGR2 can be tested using the reference voltage Vrl1 output from the temperature sensor module THS1 whose temperature characteristics have been tested.

[0096] Similarly, the difference between the digital voltage signal D_ref2_rh1 of the reference voltage Vrh1 based on the reference voltage Vref2 and the digital voltage signal D_ref1_rh1 of the reference voltage Vrh1 based on the reference voltage Vref1 is the common reference voltage Vrh1. Therefore, the following equation (3) holds: D_ref2_rh1-D_ref1_rh1=D_Δref2-D_Δref1 ···(3)

[0097] As described above, the right side of equation (3) is the digital value of ΔVref2−ΔVref1. Therefore, the following equation (4) holds true. ΔVref2-ΔVref1≒D_ref2_rh1-D_ref1_rh1 ···(4) Since ΔVref1 is known, ΔVref2 can be obtained by modifying equation (4). ΔVref2≒D_ref2_rl1-D_ref1_rl1+ΔVref1

[0098] Therefore, from the relationship ΔVptat2 / ΔVref2=constant, ΔVptat2, which is an intrinsic value indicating the temperature characteristic of the bandgap reference circuit BGR2, is obtained. In this way, the temperature characteristics of the bandgap reference circuit BGR2 can be tested even by using the reference voltage Vrh1 output from the temperature sensor module THS1 whose temperature characteristics have been tested.

[0099] Note that ΔVptat2 may be calculated using either the reference voltage Vrl1 or Vrh1 output from the temperature sensor module THS1 that has undergone a temperature characteristics test. However, it is preferable to calculate ΔVptat2 using the average value of ΔVref2 calculated from both the reference voltages Vrl1 and Vrh1.

[0100] 13 is a circuit diagram showing an example of the circuit configuration of the temperature sensor modules THS1 and THS2. Fig. 13 shows how absolute temperature proportional voltages Vptat1 and Vptat2 output from the temperature characteristic tested bandgap reference circuits BGR1 and BGR2 are A / D converted.

[0101] 13, the absolute temperature proportional voltage Vptat1 output from the temperature characteristic tested bandgap reference circuit BGR1 is input to the A / D converter ADC1 via the selector SLa1. The absolute temperature proportional voltage Vptat1 is converted into a digital voltage signal Vd1 in the A / D converter ADC1 using the reference voltage Vref1 input via the selector SLb1 as a reference signal. The digital voltage signal Vd1 is stored in the fuse bit FB1.

[0102] Similarly, the absolute temperature proportional voltage Vptat2 output from the temperature characteristic tested bandgap reference circuit BGR2 is input to the A / D converter ADC2 via the selector SLa2. The absolute temperature proportional voltage Vptat2 is converted into a digital voltage signal Vd2 by the A / D converter ADC2 using the reference voltage Vref2 input via the selector SLb2 as a reference signal. The digital voltage signal Vd2 is stored in the fuse bit FB2.

[0103] <Method for determining deterioration over time> Next, a method for determining aging deterioration of the temperature sensor modules THS1 and THS2 that have undergone a temperature characteristic test will be described with reference to Fig. 14. Fig. 14 is a circuit diagram showing an example of the circuit configuration of the temperature sensor modules THS1 and THS2. Fig. 14 shows only the signals used to determine aging deterioration of the temperature sensor modules THS1 and THS2, out of the signals shown in Fig. 11. The aging deterioration determination operation described below is performed, for example, every time the semiconductor device 200 is started up.

[0104] 14, in the temperature sensor module THS1, reference voltages Vrl1, Vrm11, Vrm12, and Vrh1, which are obtained by dividing the reference voltage Vref1 using ladder resistors, are input to the A / D converter ADC1 via a selector SLa1. The reference voltages Vrl1, Vrm11, Vrm12, and Vrh1 are converted into a digital voltage signal Vd1 in the A / D converter ADC1 using the reference voltage Vref1 input via a selector SLb1 as a reference signal. The digital voltage signal Vd1 is stored in the fuse bit FB1.

[0105] Similarly, in the temperature sensor module THS2, reference voltages Vrl2, Vrm21, Vrm22, and Vrh2, which are obtained by dividing the reference voltage Vref2 using ladder resistors, are input to the A / D converter ADC2 via a selector SLa2. The reference voltages Vrl2, Vrm21, Vrm22, and Vrh2 are converted into a digital voltage signal Vd2 in the A / D converter ADC2 using the reference voltage Vref2 input via the selector SLb2 as a reference signal. The digital voltage signal Vd2 is stored in the fuse bit FB2.

[0106] Here, FIGS. 15 and 16 are graphs that schematically show the deterioration over time in the temperature sensor module THS1. 15 and 16, two graphs are shown side by side, showing the initial state and the aged deterioration state. In both graphs, the horizontal axis is temperature (°C) and the vertical axis is voltage. In both graphs, reference voltages Vrl1, Vrm11, Vrm12, Vrh1, and Vref1 are shown.

[0107] 15 and 16 show the difference ΔVrl between the reference voltage Vrl1 and the reference voltage Vrm11, the difference ΔVrm between the reference voltage Vrm11 and the reference voltage Vrm12, and the difference ΔVrh between the reference voltage Vrm12 and the reference voltage Vrh1. The reference voltage differences ΔVrl, ΔVrm, and ΔVrh are calculated by the controller CTR1 using, for example, the digital values ​​of the reference voltages Vrl1, Vrm11, Vrm12, and Vrh1 stored in the fuse bit FB1. Of course, the reference voltage differences ΔVrl, ΔVrm, and ΔVrh may also be stored in the fuse bit FB1.

[0108] As shown in Figures 15 and 16, the reference voltage differences ΔVrl, ΔVrm, and ΔVrh change due to aging. In Figure 15, the reference voltage differences ΔVrl, ΔVrm, and ΔVrh increase due to aging. On the other hand, in Figure 16, the reference voltage differences ΔVrl, ΔVrm, and ΔVrh decrease due to aging.

[0109] 15 and 16, the reference voltage differences ΔVrl, ΔVrm, and ΔVrh can become large or small due to deterioration over time. Therefore, for example, if the amount of change from the initial value of the reference voltage differences ΔVrl, ΔVrm, and ΔVrh exceeds a predetermined threshold, the controller CTR1 determines that the reference voltage differences ΔVrl, ΔVrm, and ΔVrh are in an aging deterioration state.

[0110] As described above, in the semiconductor device 200 according to this embodiment, aging degradation can be determined based on the amount of change in the differences ΔVrl, ΔVrm, and ΔVrh between the reference voltages Vrl1, Vrm11, Vrm12, and Vrh1. Similarly, the deterioration over time of the temperature sensor modules THS2 to THS4 can be determined.

[0111] In Patent Document 2, it is necessary to provide a separate temperature sensor module for determining aging deterioration near the temperature sensor module, but this is not necessary in the semiconductor device 200 according to this embodiment.

[0112] The temperature sensor modules THS1 and THS2 formed in the same power supply domain PD1 have the same degradation rate over time. In contrast, the temperature sensor modules THS3 and THS4 formed in different power supply domains PD2 and PD3 have different degradation rates over time due to different power supply voltages and voltage application times.

[0113] In such a case, in Patent Document 2, it is necessary to provide a temperature sensor module for determining aging deterioration for each of the power supply domains PD1, PD2, and PD3. In contrast, in the semiconductor device 200 according to this embodiment, each of the temperature sensor modules THS1 to THS4 can determine aging deterioration by itself. Therefore, the temperature sensor modules THS3 and THS4 formed in the different power supply domains PD2 and PD3 can also appropriately determine aging deterioration by themselves.

[0114] Note that aging deterioration may be determined using any one of the reference voltage differences ΔVrl, ΔVrm, and ΔVrh. Also, aging deterioration may be determined using, for example, the difference between the reference voltages Vrl1 and Vrh1.

[0115] The above-mentioned program includes a set of instructions (or software code) that, when loaded into a computer, causes the computer to perform one or more functions described in the embodiments. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable media or tangible storage media include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drives (SSD) or other memory technologies, CD-ROMs, digital versatile discs (DVDs), Blu-ray discs or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices. The program may also be transmitted on a transitory computer-readable medium or a communication medium. By way of example and not limitation, transitory computer-readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals.

[0116] The invention made by the inventor has been specifically described above based on the embodiments, but it goes without saying that the present invention is not limited to the embodiments already described, and various modifications are possible within the scope of the gist of the invention. [Explanation of symbols]

[0117] 100, 200 Semiconductor device AMP BGR2~BGR4 Bandgap reference circuit BT1, BT2 bipolar transistors CTR1, CTR2 controllers FB1, FB2 fuse bits PD1, PD2, PD3 power area PIC1, PIC2 power isolation cell R1~R4 resistance SLa1, SLb1, SLa2, SLb2 selectors T1, T2 external terminals THS1~THS4 Temperature Sensor Modules

Claims

1. a bandgap reference circuit that outputs a constant reference voltage relative to temperature within a predetermined temperature range and an absolute temperature proportional voltage that is proportional to absolute temperature; Before the temperature characteristics of the bandgap reference circuit are inspected, the temperature dependencies of the reference voltage and the absolute temperature proportional voltage are measured in advance for a plurality of samples; When the temperature characteristics are inspected, a difference ΔVptat between the absolute temperature proportional voltage of the bandgap reference circuit at the predetermined temperature and a median of the absolute temperature proportional voltages of the plurality of samples is calculated based on a difference ΔVref between the reference voltage of the bandgap reference circuit at the predetermined temperature and a median of the reference voltages of the plurality of samples; When the temperature characteristics are inspected, the ratio of the difference ΔVref to the difference ΔVptat is kept constant regardless of temperature. Semiconductor device.

2. When the temperature characteristic is inspected, setting the semiconductor device to a lower limit temperature and an upper limit temperature within which operation is guaranteed; The difference ΔVptat is calculated based on an average value of the difference ΔVref at the lower limit temperature and the upper limit temperature. The semiconductor device according to claim 1 .

3. 2. The semiconductor device according to claim 1, wherein aging degradation is determined based on a change in a difference between a plurality of reference divided voltages obtained by dividing the reference voltage output from the bandgap reference circuit whose temperature characteristics have been inspected.

4. the bandgap reference circuit is a first bandgap reference circuit that outputs a first reference voltage as the reference voltage; a second bandgap reference circuit formed in a power supply domain different from that of the first bandgap reference circuit and outputting a second reference voltage; determining aging deterioration based on the amount of change in difference between a plurality of reference divided voltages obtained by dividing the second reference voltage output from the second bandgap reference circuit whose temperature characteristics have been inspected; The semiconductor device according to claim 3 .

5. the bandgap reference circuit is a first bandgap reference circuit that outputs a first reference voltage as the reference voltage; a second bandgap reference circuit that outputs a second reference voltage; a first analog-to-digital converter to which the first reference voltage is input; a second analog-to-digital converter to which the second reference voltage is input, When the temperature characteristics of the second bandgap reference circuit are checked, a first reference divided voltage obtained by dividing the first reference voltage output from the first bandgap reference circuit whose temperature characteristics have been inspected is converted into a first digital signal by the first analog-to-digital converter using the first reference voltage as a reference, and is also converted into a second digital signal by the second analog-to-digital converter using the second reference voltage as a reference; the temperature characteristics of the second bandgap reference circuit are checked based on a difference between the first and second digital signals; The semiconductor device according to claim 1 .

6. A method for testing temperature characteristics of a bandgap reference circuit that outputs a constant reference voltage with respect to temperature and an absolute temperature proportional voltage that is proportional to absolute temperature, comprising: Before inspecting the temperature characteristics of the bandgap reference circuit, the temperature dependence of the reference voltage and the absolute temperature proportional voltage is measured in advance for a plurality of samples; When inspecting the temperature characteristics, a difference ΔVptat between the absolute temperature proportional voltage of the bandgap reference circuit at the predetermined temperature and the median of the absolute temperature proportional voltages of the plurality of samples is calculated based on a difference ΔVref between the reference voltage of the bandgap reference circuit at the predetermined temperature and the median of the reference voltages of the plurality of samples; When inspecting the temperature characteristics, the ratio of the difference ΔVref to the difference ΔVptat is kept constant regardless of temperature. Temperature characteristics inspection method.

7. When inspecting the temperature characteristics, setting the bandgap reference circuit to a lower limit temperature and an upper limit temperature at which operation is guaranteed; calculating the difference ΔVptat based on an average value of the difference ΔVref at the lower limit temperature and the upper limit temperature; The temperature characteristic inspection method according to claim 6.

8. 7. The temperature characteristics testing method according to claim 6, wherein aging deterioration is determined based on an amount of change in a difference between a plurality of reference divided voltages obtained by dividing the reference voltage output from the bandgap reference circuit whose temperature characteristics have been tested.

9. the bandgap reference circuit is a first bandgap reference circuit that outputs a first reference voltage as the reference voltage; a second bandgap reference circuit formed in a power supply domain different from that of the first bandgap reference circuit and outputting a second reference voltage; determining aging deterioration based on the amount of change in difference between a plurality of reference divided voltages obtained by dividing the second reference voltage output from the second bandgap reference circuit whose temperature characteristics have been inspected; The temperature characteristic inspection method according to claim 8.

10. the bandgap reference circuit is a first bandgap reference circuit that outputs a first reference voltage as the reference voltage; When inspecting the temperature characteristics of the second bandgap reference circuit that outputs the second reference voltage, a first reference divided voltage obtained by dividing the first reference voltage output from the first bandgap reference circuit whose temperature characteristics have been inspected is converted into a first digital signal by a first analog-to-digital converter using the first reference voltage as a reference, and also converted into a second digital signal by a second analog-to-digital converter using the second reference voltage as a reference; checking the temperature characteristics of the second bandgap reference circuit based on a difference between the first and second digital signals; The temperature characteristic inspection method according to claim 6.

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