JP2009109314A - Semiconductor device and its inspecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device which enables to inspect a temperature detecting circuit formed on a semiconductor integrated circuit without additionally installing temperature control devices such as a remote temperature sensor and the like, and also to provide its inspecting method. <P>SOLUTION: A semiconductor unit 100 is provided with: a temperature detecting circuit 110 which comprises a first current source 111 outputting the first current which changes according to temperature change, a second current source 112 enabling to control the output current with a reference signal VREF and outputting the second current which is substantially constant with respect to temperature, and a current-voltage converting circuit 113 which inputs the difference between the first current and the second current as a third current and outputs as the temperature signal VTMP after converting to voltage; and a signal processing circuit 120, formed on the same chip of the temperature detecting circuit 110, whose heating value changes with a setting signal VSET. A determining means determines whether the semiconductor unit 100 is suitable for use by comparing the temperature signal VTMP outputted from the temperature detecting circuit 110, when the setting signal VSET and the reference signal VREF are applied, with the inspection reference value VTEST. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor device and a semiconductor device inspection method, and more particularly, to a semiconductor device having a function of inspecting a temperature detection circuit formed on a semiconductor substrate and a semiconductor device inspection method.

2. Description of the Related Art A semiconductor device is known in which a temperature detection circuit is formed on a semiconductor integrated circuit, and an environmental temperature is measured based on the output of the temperature detection circuit. It is necessary to inspect whether the temperature detection circuit in such a semiconductor device operates properly, and a semiconductor inspection device as disclosed in Patent Document 1 for this purpose is known.
JP 2003-4799 A

  As shown in FIG. 8, the semiconductor inspection apparatus disclosed in Patent Document 1 places the semiconductor element 10 to be inspected on the mounting table 11, and controls the heat flow means 14 by the temperature controller 31. Change the temperature. In this state, the remote temperature sensor 30 measures the temperature of the mounting table 11 in a non-contact manner, and controls the heat generator and the heat absorber of the heat distribution means 14 so that the temperature of the semiconductor element 10 becomes a predetermined temperature. Therefore, the remote temperature sensor 30 can measure the temperature of the semiconductor element 10 from a position away from the mounting table 11 in a non-contact manner, so that it is not necessary to embed the temperature measuring element in the mounting table 11 and the signal line is routed. As a result, it is not affected by noise and the signal line is not disconnected.

  In such a conventional semiconductor inspection device, it is necessary to provide a temperature control device such as a heat distribution means, a temperature controller, and a remote temperature sensor in order to heat the semiconductor element to a desired temperature and inspect the semiconductor element while absorbing heat. . For this reason, in the measurement of the temperature measurement circuit formed on the semiconductor integrated circuit, there is a problem that the cost increases.

The present invention has been made in view of such circumstances, and a temperature detection circuit formed on a semiconductor integrated circuit without additionally installing a temperature control device such as a heat distribution means, a temperature controller, and a remote temperature sensor. An object of the present invention is to provide a semiconductor device that can be inspected.

  In order to achieve the above object, the semiconductor device according to the first aspect of the invention has a first current source that outputs, as a first current, a current that changes in response to a temperature change, and an output current that is generated by a reference signal input from the outside. A second current source that outputs a controllable and substantially constant current as a second current, and a difference between the first current and the second current is input as a third current, and the third current is converted into a voltage. A temperature detection circuit configured by a current-voltage conversion circuit that converts and outputs as a temperature signal; and a signal processing circuit that is formed on the same chip as the temperature detection circuit and whose heat generation amount is changed by a setting signal input from the outside; On the same chip, control signal generation means for outputting the setting signal and the reference signal, and inspection reference value holding means for holding the inspection reference value of the semiconductor unit; It said temperature signal corresponding to the setting signal and the reference signal is compared with the inspection standard value, comprising a determining means for determining suitability of the semiconductor unit.

  According to a second aspect of the present invention, in the semiconductor device according to the first aspect, the signal processing circuit includes an analog circuit whose current consumption changes according to the setting signal input from the outside.

  According to a third aspect of the present invention, in the semiconductor device according to the first aspect, the signal processing circuit comprises a digital circuit whose operating frequency can be changed according to the setting signal input from the outside.

Furthermore, a semiconductor device according to a fourth invention is the above first invention,
The first current source is connected to a first voltage source in which each first terminal outputs a first voltage, and an area of a pn junction is 1: N (N is an arbitrary positive value). A first resistor having one end connected to the second terminal of the second diode, and a first conductive terminal having a first terminal connected to the second terminal of the first diode; A first transistor of the first type, a first terminal connected to the other end of the first resistor, and a control terminal connected to a second terminal and a control terminal of the first transistor. And a second terminal connected to a control terminal and a second terminal of the first-conductivity-type first transistor. The second transistor is connected to a second power source that outputs a second voltage. A third transistor of two conductivity type, a first terminal connected to the second power source, and a control terminal; A fourth transistor of the second conductivity type commonly connected to a control terminal of the second transistor of the second conductivity type, and a second terminal of which the second terminal is connected to the second terminal of the second transistor; A second conductive type second terminal having a terminal connected to the second voltage source, a control terminal commonly connected to the control terminals of the third and fourth transistors, and a second terminal serving as an output terminal of the first current; 5 transistors,
The second current source includes a first operational amplifier having a non-inverting input terminal connected to the reference signal input terminal, one end connected to the inverting input terminal of the first operational amplifier, and the other end connected to the first operational amplifier. A second resistor connected to the two voltage sources, a control terminal connected to the output terminal of the first operational amplifier, and a first terminal connected to the inverting input terminal of the first operational amplifier. A second conductivity type transistor; and a current mirror circuit having an input terminal connected to the second terminal of the sixth second conductivity type transistor and an output terminal serving as an output terminal of the second current,
The current-voltage conversion circuit has a non-inverting input terminal connected to the reference signal input terminal, an inverting input terminal connected to the first current output terminal and the second current output terminal, and an output terminal connected to the temperature signal. A second operational amplifier serving as an output terminal of the second operational amplifier, a third resistor having one end connected to the inverting input terminal of the second operational amplifier and the other end connected to the output terminal of the second operational amplifier; Consists of.

  According to a fifth aspect of the present invention, there is provided a semiconductor device inspection method in which a first setting signal for setting power consumption is set in a signal processing circuit provided on the same substrate as the temperature detection circuit, and the temperature detection circuit at this time The first temperature signal is held, a second setting signal for setting power consumption is set in the signal processing circuit, the second temperature signal is held from the temperature detection circuit at this time, and the first temperature signal is set. A difference value between the second temperature signal and the second temperature signal is obtained, and it is determined whether or not the difference value is within an allowable range of the inspection reference value.

  According to a sixth aspect of the present invention, there is provided a method for inspecting a semiconductor device, comprising: a temperature detection circuit, wherein an output current can be controlled by a reference signal; and a current source that outputs a substantially constant current with respect to temperature. A first reference signal is set, a first temperature signal of the temperature detection circuit at this time is held, a second reference signal is set for the current source, and a second reference signal of the temperature detection circuit at this time is set And a difference value between the first temperature signal and the second temperature signal is obtained, and it is determined whether or not the difference value is within an allowable range of the inspection reference value.

  According to a seventh aspect of the present invention, there is provided a semiconductor unit including a first current source that outputs, as a first current, a current whose output changes according to a temperature change, an output current that can be controlled by a reference signal input from the outside, A second current source that outputs a substantially constant current as a second current, and a difference between the first current and the second current is input as a third current, and the third current is converted into a voltage and output as a temperature signal And a signal processing circuit which is formed on the same chip as the temperature detection circuit and whose heat generation amount is changed by a setting signal input from the outside.

  According to an eighth aspect of the present invention, there is provided a semiconductor inspection apparatus including a first current source that outputs a first current whose output changes according to a temperature change, and a second current that can be controlled by a reference signal and is substantially constant with respect to temperature. A temperature detection circuit configured by a second current source that outputs a difference between the first current and the second current as a third current that is converted into a voltage and output as a temperature signal A semiconductor inspection apparatus for a semiconductor unit comprising a signal processing circuit whose calorific value changes according to a setting signal, the control signal generating means for outputting the setting signal and the reference signal, and an inspection reference value for the semiconductor unit. An inspection reference value holding means for holding; and a determination means for comparing the setting signal and the temperature signal corresponding to the reference signal with the inspection reference value to determine suitability of the semiconductor unit. .

  According to the first aspect of the present invention, the temperature signal that changes in accordance with the change in the setting signal and the measurement result of the temperature signal that changes in accordance with the change in the reference signal are compared with the inspection reference value to form on the semiconductor unit. It is possible to determine the suitability of the temperature detection circuit. Since such a semiconductor device does not require a temperature control device for the inspection of the temperature detection circuit, the cost for the inspection of the on-chip temperature detection circuit can be reduced.

  According to the second and third aspects of the invention, a signal processing circuit capable of controlling the amount of heat generated by a setting signal input from the outside can be realized on the semiconductor unit. Therefore, it is possible to provide a semiconductor device capable of creating a temperature condition necessary for the inspection of the temperature detection circuit without using a heat distribution means or a temperature controller.

  According to the fourth invention, both the change of the temperature signal output corresponding to the change of the reference signal and the change of the temperature signal output corresponding to the temperature change of the semiconductor device controlled by the setting signal are performed. A temperature detection circuit capable of detection can be provided.

  According to the fifth invention, when the signal processing circuit capable of controlling the heat generation amount by the setting signal is provided, the semiconductor device is inspected based on the difference value of the temperature signal corresponding to the change of the setting signal at at least two points. ing. For this reason, it is possible to determine whether the temperature detection circuit operates properly in the change range of the calorific value at least at two points.

  According to the sixth invention, when the output current can be controlled by the reference signal and the current source outputs a substantially constant current with respect to the temperature, the temperature corresponding to the change of the reference signal at at least two points. The semiconductor device is inspected based on the difference value of the signal. For this reason, it is possible to determine whether the temperature detection circuit operates properly in the current change range at at least two points.

  According to the seventh aspect of the invention, there is provided a semiconductor unit that can easily inspect the suitability of the temperature signal detection circuit by changing the reference signal and the setting signal, and does not require a temperature control device or the like for the inspection of the temperature detection circuit. can do.

  According to the eighth invention, the reference signal and the setting signal are changed, and at that time, the determination means determines the suitability based on the temperature signal from the temperature detection circuit. It is possible to provide a semiconductor inspection apparatus that does not require the above.

(First embodiment)
A preferred embodiment will be described below using a semiconductor device to which the present invention is applied according to the drawings. FIG. 1 is a block diagram of a semiconductor device 1000 according to the first embodiment. The semiconductor device 1000 includes a semiconductor unit 100, a control signal generation unit 200, a determination unit 300, and an inspection reference value holding unit 400.

  In the semiconductor unit 100, a temperature detection circuit 110 and a signal processing circuit 120 are formed on the same chip and unitized. The temperature detection circuit 110 includes a first current source 111, a second current source 112, a current-voltage conversion circuit 113, and a differentiator 114. The first current source 111 outputs a first current IPTAT whose output changes according to a temperature change. The second current source 112 outputs a second current ICONST that depends on a reference signal VREF input from the outside and is substantially constant with respect to temperature.

  The differentiator 114 outputs the difference between the first current IPTAT and the second current ICONST as a third current. The subtractor 114 may be simply connected in a circuit so as to draw the first current from the second current, and may not have a special circuit element. The current-voltage conversion circuit 113 receives the third current, converts the third current into a voltage, and outputs it as a temperature signal VTMP.

  The signal processing circuit 120 is formed on the same chip as the temperature detection circuit 110, and the amount of heat generated is changed by a setting signal VSET set from the outside. The signal processing circuit 120 is not a circuit specially provided for generating heat, but is a circuit for the semiconductor unit 100 to perform signal processing, actuator driving, and the like that should be originally performed.

  The control signal generation means 200 outputs a setting signal VSET and a reference signal VREF in order to check whether the temperature detection circuit 110 of the semiconductor unit 100 operates properly. The inspection reference value holding unit 400 holds the inspection reference value VTEST of the semiconductor unit 100. The determination unit 300 compares the temperature signal VTEMP and the inspection reference value VTEST to determine whether the temperature detection circuit 110 in the semiconductor unit 100 is appropriate.

  In the semiconductor device 1000, the semiconductor unit 100 is mounted on an inspection apparatus including the control signal generation unit 200, the determination unit 300, and the inspection reference value holding unit 400, and the suitability of the temperature detection circuit 110 in the semiconductor unit 100 is inspected. . Note that at least one means in the inspection apparatus has a CPU (Central Processing Unit), and controls each means according to a flowchart to be described later, thereby inspecting the temperature detection circuit in the semiconductor device 1000. .

  Next, the operating principle of the semiconductor device 1000 configured as described above will be described with reference to FIGS. First, the relationship between the setting signal VSET input to the semiconductor unit 100 and the temperature signal VTEMP output corresponding to the reference signal VREF will be described.

When the current / voltage conversion coefficient of the current-voltage conversion circuit 113 is G, the temperature signal VTEMP is output from the second current source 112 by the differentiator 114 from the second current source 112 and the first current source 111 output from the first current source 111. Since the difference of the current ICONST is a voltage converted into a voltage by the current-voltage conversion circuit 113, it is expressed by the following formula 1.
VTMP = G (IPTAT (T) -ICONST (VREF)) (Formula 1)
Here, T in Formula 1 indicates the absolute temperature of the semiconductor unit 100.

Next, a change in the temperature signal VTMP measured when the setting signal VSET is changed under the condition that the reference signal VREF is constant will be described. Since the heat generation amount of the signal processing circuit 120 changes according to the setting signal VSET, the absolute temperature T of the semiconductor unit 100 is expressed as a function of the setting signal VSET. That is,
T = T (VSET) (Formula 2)
Is established. From this, Equation 1 can be expressed as follows using Equation 2.
VTMP = G {IPTAT (T (VSET))-ICONST (VREF)}
= G (IPTAT (VSET) -ICONST (VREF)) (Equation 3)

Therefore, the first temperature signal VTMP_norm1 output in response to the first setting signal VSET_norm and the second temperature signal VTMP_test1 output in response to the second setting signal VSET_test are respectively expressed as It is expressed by the following formula.
VTMP_norm1 = G (IPTAT (VSET_norm) −ICONST (VREF)) (Formula 4)
VTMP_test1 = G (IPTAT (VSET_test) −ICONST (VREF)) (Formula 5)

  When the absolute temperature T of the semiconductor unit 100 rises linearly in proportion to the setting signal VSET, the relationship between the setting temperature VSET and the temperature signal VTMP is expressed as shown in FIG. Here, for simplification, only the case where the absolute temperature T is linearly proportional to the set temperature VSET is illustrated, but as shown in Equation 2, between the absolute temperature T of the semiconductor unit 100 and the set signal VSET, It suffices if the correspondence represented by an arbitrary monotone function is established.

However, the first setting signal VSET_norm and the second setting signal VSET_test can take arbitrary values as long as VSET_norm ≠ VSET_test is within the operation rating of the semiconductor unit 100 to be inspected. Therefore, the difference between Equation 4 and Equation 5 is
VTMP_norm1−VTMP_test1 = G (IPTAT (VSET_norm) −IPTAT (VSET_test))
... (Formula 6)
It is expressed.

  That is, the determination unit 300 measures the first temperature signal VTMP_norm1 output corresponding to the first setting signal VSET_norm and the second temperature signal VTMP_test1 output corresponding to the second setting signal VSET_test, The first current source in the temperature detection circuit 110 is determined by determining whether or not the difference is within the range of the first inspection reference value VTEST = VTEST1 ± ΔVTEST1 read from the inspection reference value holding means 400. Whether or not 111 and the current-voltage conversion circuit 113 are operating normally can be determined.

  Here, VTEST1 is a standard value of VTMP_norm1-VTMP_test1 expected when the semiconductor unit 100 is a non-defective product. ΔVTEST1 is an allowable range for determining the inspected semiconductor unit 100 as a non-defective sample.

  Next, changes in the temperature signal VTMP measured when the setting signal VSET is constant, that is, when the absolute temperature T of the semiconductor unit 100 is constant and the reference signal VREF is changed in this state will be described.

First, the third temperature signal VTMP = VTMP_norm2 output in response to the first reference signal VREF = VREF_norm and the fourth temperature signal VTMP_test2 output corresponding to the second reference signal VREF = VREF_test are respectively Using Equation 1, it is represented by the following equation.
VTMP_norm2 = G (IPTAT (T) -ICONST (VREF_norm)) (Formula 7)
VTMP_test2 = G (IPTAT (T) -ICONST (VREF_test)) (Expression 8)

  Further, when the second current ICONST is expressed by a linear function of the reference signal VREF, the relationship between the reference signal VREF and the temperature signal VTMP is expressed as shown in FIG. However, as long as VREF_norm ≠ VREF_test, the first reference signal VREF_norm and the second reference signal VREF_test can take arbitrary values as long as they are within the operation rating of the semiconductor unit 100 to be inspected. The reference signal VREF may be an analog signal or a digital signal corresponding to the analog signal.

The difference between the third temperature signal VTMP_norm2 and the fourth temperature signal VTMP_test2 is as follows:
VTMP_norm2−VTMP_test2 = −G (ICONST (VREF_norm) −ICONST (VREF_test))
... (Formula 9)
As required.

  That is, the determination unit 300 measures the third temperature signal VTEM_norm2 output corresponding to the first reference signal VREF_norm and the fourth temperature signal VTMP_test2 output corresponding to the second reference signal VREF_test, It is determined whether or not the difference is within the range of the second inspection reference value VTEST = VTEST2 ± ΔVTEST2 read from the inspection reference value holding means 400. Thus, it can be determined whether or not the second current source 112 and the current-voltage conversion circuit 113 in the temperature detection circuit 110 are operating normally.

  Here, VTEST2 is a standard value of VTMP_norm2-VTMP_test2 expected when the semiconductor unit 100 is a good product. ΔVTEST2 represents an allowable range for determining the inspected semiconductor unit 100 as a non-defective sample.

  Next, the operation at the time of inspection of the semiconductor device 1000 will be described using the flowchart shown in FIG. This flowchart shows an example of an inspection procedure for the semiconductor device 1000. When entering the inspection flow, first, the control signal generating means 200 applies the first setting signal VSET = VSET_norm to the semiconductor unit 100 (S1). When the first setting signal VSET_norm is applied, the signal processing circuit 120 operates with electric power corresponding to the first setting signal, and generates heat accordingly.

  Subsequently, the determination unit 300 measures the first temperature signal VTMP = VTMP_norm1 output from the semiconductor unit 100, and holds the measurement result in a memory (not shown) in the determination unit 300 (S2). That is, here, the temperature signal corresponding to the temperature of the semiconductor unit 100 is detected by the temperature detection circuit 110.

  Thereafter, the control signal generation means 200 applies the second setting signal VSET = VSET_test to the semiconductor unit 100 (S3). When the second setting signal VSET_test is applied, the signal processing circuit 120 operates with power corresponding to the second setting signal, and generates heat accordingly.

  Subsequently, the determination unit 300 measures the second temperature signal VTMP = VTMP_test1 output from the semiconductor unit 100, and holds the measurement result in a memory (not shown) in the determination unit 300 (S4). That is, a temperature different from that in step S1 is set, and the measurement result of the temperature of the semiconductor unit 100 detected by the temperature detection circuit 110 in this state is held.

  Next, the determination unit 300 calculates the difference between the first temperature signal VTMP_norm1 and the second temperature signal VTMP_test1, and the calculation result is the first test reference value VTEST = VTEST1 ± ΔVTEST1 read from the test reference value holding unit 400. It is determined whether it is within the range (S5). As a result of the determination, if the difference value between the first and second temperature signals is within the allowable range of the first inspection reference value, the process proceeds to step S5, and if it is outside the allowable range, the process proceeds to step S12.

  That is, in steps S1 to S5, the heat generation amount in the signal processing circuit 120 is changed by changing the setting signal VSET while keeping the reference signal VREF constant (that is, constant ICONST). Since the change of the setting signal VSET is determined in advance, if the temperature detection circuit 110 operates normally, the variation in the difference value between the first and second temperature signals VTMP at that time is within the allowable range ΔVTEST1. Fits in. As a result of the determination in step S5, if the difference value is within the range of the inspection reference value, the determination is accepted, and the process proceeds to the next inspection in step S6 and below. In S12, it is determined as rejected.

  As a result of the determination in step S5, if the difference value of the temperature signal is within the inspection reference value and the semiconductor unit 100 to be inspected passes, then the control signal generating means 200 first outputs the first reference signal VREF = VREF_norm. Is applied (S6). Subsequently, the determination unit 300 measures the third temperature signal VTMP = VTMP_norm2 output from the semiconductor unit 100, and holds the measurement result in the memory in the determination unit 300 (S7).

  Next, the control signal generating means 200 applies the second reference signal VREF = VREF_test (S8). Subsequently, the determination unit 300 measures the fourth temperature signal VTMP = VTMP_test2 output from the semiconductor unit 100, and holds the measurement result in the memory in the determination unit 300 (S9).

  Next, the determination unit 300 calculates the difference between the third temperature signal VTMP_norm2 and the fourth temperature signal VTMP_test2, and the calculation result is the second test reference value VTEST = VTEST2 ± read from the test reference value holding unit 400. It is determined whether it is within the range of ΔVTEST2 (S10). As a result of the determination, if the difference value between the third and fourth temperature signals is within the range of the second inspection reference value, the process proceeds to step S11, and if not, the process proceeds to step S12.

  That is, in step S6 to step S10, the setting signal VSET is kept constant (that is, the amount of heat generated by the signal processing circuit 120 is constant), the reference signal VREF is changed, depends on the reference signal VREF, and the temperature The second current ICONST that is substantially constant is changed. Since the amount of heat generated in the signal processing circuit 120 does not change, the first current IPTAT does not change, but the second current ICONST changes, so that the temperature signal VTMP changes eventually. Since the change of the reference signal VREF is determined in advance, if the temperature detection circuit 110 is operating normally, the variation in the difference value between the third and fourth temperature signals at that time is within the allowable range ΔVTEST2. It will fit.

  As a result of the determination in step S10, if the difference value is within the allowable range of the inspection reference value, the process proceeds to step S11 and is determined to be acceptable. On the other hand, if the difference value is outside the allowable range of the inspection reference value as a result of the determination, the process proceeds to step S12, and the semiconductor unit 100 to be inspected is rejected. The determination result is output and displayed externally so that only non-defective samples can be selected.

  As described above, in the present embodiment, the fluctuation of the temperature signal VTMP corresponding to the fluctuation of the setting signal VSET indicates the response represented by Equation 6, and the fluctuation of the temperature signal VTMP corresponding to the fluctuation of the reference signal VREF. Is provided with a determination unit 300 that determines that only a sample (semiconductor unit 100) that can confirm both of the responses represented by Equation 9 is a non-defective product. For this reason, the semiconductor device 1000 does not need to provide a temperature control device such as a heat distribution means, a temperature controller, and a remote temperature sensor, and can determine whether the temperature detection circuit 110 is appropriate.

  Further, when the temperature detection circuit 110 is inspected, the inspection can be performed by using only one of the setting signal VSET and the reference signal VREF. However, both the signals VSET and the reference signal VREF are used as in the present embodiment. Thus, it can be determined whether both the first current source 111 and the second current source 112 are operating properly.

  Further, in the present embodiment, two signals (VSET_norm and VSET_test, or VREF_norm and VREF_test) are applied to the setting signal VSET and the reference signal VREF, respectively, and inspection is performed at exactly two points on the graph. . Therefore, it can be determined whether or not the operation conforms to the standard.

  In the present embodiment, the control signal generation unit 200, the determination unit 300, and the inspection reference value holding unit 400 have been described as an integrated inspection apparatus, but may be individual components or apparatuses that constitute the semiconductor device 1000. . Further, any one or more elements of the control signal generation unit 200, the determination unit 300, and the inspection reference value holding unit 400 may be formed on a semiconductor chip such as a microcomputer. Furthermore, any one or more elements of the control signal generation unit 200, the determination unit 300, and the inspection reference value holding unit 400 may be formed on the same substrate as the semiconductor unit 100.

  Further, as the inspection procedure in this embodiment, the setting signal VSET is changed first, and then the reference signal VREF is changed. This is for changing the temperature of the semiconductor unit 100 itself and giving priority to the inspection as to whether or not the first current source 111 having temperature dependency at that time is operating normally. However, of course, when both the first current source 111 and the second current source 112 are inspected, the reference signal VREF may be changed first.

Next, the configuration of the signal processing circuit 120 of the semiconductor device 1000 will be described with reference to FIG. FIG. 5 is an internal block diagram of the signal processing circuit 120. The analog circuit 121 is a circuit whose current consumption changes according to the input setting signal VSET. The consumption current I of the analog circuit 121 is
I = I (VSET) (Equation 10)
It is expressed.

Further, assuming that the equivalent resistance of the analog circuit 121 is R, the work rate P _ANALOG of the analog circuit 121 is expressed by = P _ANALOG I ² R. _Therefore, the amount of heat generated by the analog circuit 121 from time t0 to time t1. Q is represented by the following formula 11 (Equation 1).

In addition, when the constant volume specific heat of the semiconductor unit 100 is Cv, it is defined as Cv≡dQ / dT.
dT · Cv = dQ (Formula 12)
Can be written.

Therefore, the minute change dT of the absolute temperature of the semiconductor unit 100 in the minute time dt is expressed by Expression 13 (Expression 2) using Expression 10 and Expression 11.

When Expression 13 is modified by adding the influence of the case where P _DISP is the amount of heat dissipation per unit time of the semiconductor unit 100, the rise when the semiconductor unit 100 is heated from time t0 to time t1 by the signal processing circuit 120. The temperature dT is expressed by the following Expression 14 (Equation 3).
Therefore, the absolute temperature T of the semiconductor unit 100 can be controlled by the setting signal VSET.

  As described above, in this embodiment, the temperature of the semiconductor unit 100 having the signal processing circuit 120 constituted by the analog circuit 121 on the substrate can be controlled by adjusting the setting signal VSET input from the outside. Therefore, it is possible to create a temperature condition necessary for the inspection of the temperature detection circuit 110 without specially providing a heat distribution means or a temperature controller.

  Next, a detailed configuration of the temperature detection circuit 110 of the semiconductor device 1000 will be described with reference to FIG. FIG. 7 is a circuit diagram of the temperature detection circuit 110. The temperature detection circuit 110 includes a first current source 111, a second current source 112, and a current-voltage conversion circuit 113. Although the differentiator 114 is illustrated in FIG. 1, the function of the differentiator 114 is performed by the transistor Q <b> 5 of the first current source 111, and thus the differencer 114 is not specially provided.

  As described above, the first current source 111 outputs a current whose output changes according to a temperature change as the first current IPTAT. The second current source 112 outputs a second current ICONST whose output current can be controlled by the reference signal VREF input from the control signal generating means 200 and is substantially constant with respect to temperature. The current-voltage conversion circuit 113 inputs the difference between the first current IPTAT and the second current ICONST as a third current, converts the third current into a voltage, and outputs it as a temperature signal VTMP.

  The first current source 111 includes a first diode D1 and a first transistor connected between a first voltage source VSS1 that outputs a first voltage and a second voltage source VSS2 that outputs a second voltage. A series circuit of Q1 and a third transistor Q3, a series circuit of a second diode D2, a first resistor Rd, a second transistor Q2 and a fourth transistor Q4, and an output terminal of a current mirror circuit CM1 to be described later The fifth transistor Q5 is connected between the second voltage source VSS2.

The first terminal of the first diode D1 is connected to the first voltage source VSS1, and the second terminal is connected to the first terminal of the first transistor Q1. The first terminal of the second diode D2 is connected to the first voltage source VSS1, and the second terminal of the second transistor Q2 is connected to the first voltage of the second transistor Q2 via the first resistor Rd (resistance value R _D ). Connected to the terminal. Assuming that the area of the pn junction of the first diode D1 is 1, the area of the pn junction of the second diode D2 is N, and the area ratio of both pn junctions is 1: N (N is an arbitrary positive value) It has become.

  The first and second transistors Q1 and Q2 are formed of a first conductivity type transistor, and the control terminals of both transistors Q1 and Q2 are connected to each other. The control terminal of the second transistor Q2 is also connected to the second terminal of the second transistor Q2. The second terminal of the first transistor Q1 is connected to the second terminal of the third transistor Q3, and the second terminal of the second transistor Q2 is connected to the second terminal of the fourth transistor Q4.

  The third and fourth transistors Q3 and Q4 are composed of a second conductivity type transistor, and the control terminals of both transistors Q3 and Q4 are connected to each other. The control terminal of the third transistor Q3 is also connected to the second terminal of the third transistor Q3. The first terminals of the third and fourth transistors Q3 and Q4 are connected to the second voltage source VSS2.

  The fifth transistor Q5 is composed of a second conductivity type transistor, the control terminal is connected to the control terminals of the third and fourth transistors, the first terminal is connected to the second voltage source VSS2, and the second terminal The terminal becomes an output terminal of the first current IPTAT.

The second current source 112 includes a first operational amplifier A1, a second resistor Rofst, a sixth transistor Q6, and a current mirror circuit CM1. The non-inverting input terminal of the first operational amplifier A1 is connected to the terminal of the reference signal VREF, and the inverting input terminal is connected to one end of the second resistor _Rofst whose resistance value is R _OFST . The other end of the second resistor Rofst is connected to the second power supply VSS2.

  The sixth transistor Q6 is composed of a second conductivity type transistor, its control terminal is connected to the output terminal of the first operational amplifier A1, the first terminal is the non-inverting input terminal of the first operational amplifier and the second Connected to one end of resistor Rofst. The current Iofst flows through the sixth transistor Q6 and the second resistor Rofst.

  The input terminal of the current mirror circuit CM1 is connected to the second terminal of the sixth transistor Q6, and the output terminal is connected to the output terminal of the first current IPTAT described above and the inverting input terminal of the second operational amplifier A2 described later. Has been. The current Iofst flows through the input terminal of the current mirror circuit CM1, and the second current ICONST flows through the output terminal.

The current-voltage conversion circuit 113 includes a second operational amplifier A2 and a third resistor Rg having a resistance value R _G. The non-inverting input terminal of the second operational amplifier A2 is connected to the terminal of the reference signal VREF, and the second resistor Rg is connected between the inverting input terminal and the output terminal. Further, as described above, the inverting input terminal is connected to the output terminal of the second current ICONST and the output terminal of the first current IPTAT of the current mirror circuit CM1.

  Although the temperature detection circuit 110 according to the present embodiment is configured as described above, a detailed operation will be described in the case where the first and second terminals are assigned as follows. The first terminals of the diodes D1 and D2 are anodes, and the second terminal is a cathode. The first conductivity type transistor is a PMOS transistor, and the second conductivity type transistor is an NMOS transistor. The first terminal of the PMOS transistor and NMOS transistor is the source, the second terminal is the drain, and the control terminal is the gate. Further, it is assumed that the voltage of the first voltage source VSS1 is higher than the voltage of the second voltage VSS2.

The operation of the temperature detection circuit 110 when each element is assigned as described above is as follows. First, the operation of the first current source 111 will be described. In general, the forward voltage V _F of the diode is given by Equation 15 (Equation 4).

Here, Io is a forward current flowing through the diode, and Is is a reverse saturation current of the diode. V _T is a value called a thermal voltage, and is expressed by a relational expression of V _T = kT / q. Note that q is an elementary charge amount and k is a Boltzmann constant.

When the diode operates in the diffusion current region, since Is << Io, Equation 15 can be approximated as Equation 16 (Equation 5).

The transistors Q1 and Q2 configured by MOS transistors are transistors having the same size and the same characteristics, and the transistors Q3 and Q4 configured by MOS transistors are the same size and have the same characteristics. In this case, when the first current source 111 is operated by a startup circuit (not shown), in the system constituted by the diode D1, the MOS transistor Q1 and the diode D2, the resistor Rd, and the MOS transistor Q2, the equation 16 is considered. 17 (Equation 6) holds.

Here, l1 is the current flowing through the diode D1, I2 is the current flowing through the diode D2, V _GS1 is a gate-source voltage, V _GS2 of the MOS transistor Q1 is the gate-source voltage of the MOS transistor Q2. N is a pn junction area ratio of the diode D2 to the diode D1, and is an arbitrary positive value.

Now, the gates of the MOS transistors Q3 and Q4 are connected in common, and the sources thereof are connected to the second voltage source VSS2, so that the gate-source voltage V _GS of the MOS transistors is equal. Since the MOS transistors Q3 and Q4 have the same size and the same characteristics, the current I1 flowing through the MOS transistor Q3 is equal to the current I2 flowing through the MOS transistor Q4.

Focusing on the MOS transistors Q1 and Q2, the currents flowing through the MOS transistors Q1 and Q2 are equal, and the sizes of the MOS transistors Q1 and Q2 are the same, so that V _GS1 = V _GS2 . If I1 = I2 = Io, Expression 17 becomes Expression 18 (Expression 7) below.

If Io is calculated from this equation 18,
Io = (V _T / R _D ) × ln (N) (Equation 19)
It becomes. That is, it can be seen that the current I1 = I2 = Io flowing through the MOS transistors Q1 and Q2 is a constant other than the thermal voltage V _T , and thus the current Io is proportional to the thermal voltage V _T.

In the current mirror circuit composed of the MOS transistors Q3, Q4, and Q5, when the ratio of the gate width of the MOS transistor Q5 to the gate width of the MOS transistors Q3 and Q4 is M1, the first current that flows from the drain of the MOS transistor Q5. The current IPTAT is expressed by the following Equation 20.
IPTAT = M1 × Io = M1 × (kT / qR _D ) ln (N) (Equation 20)
That is, it can be seen that the first current IPTAT flowing through the MOS transistor Q5 is a constant other than the absolute temperature T, and therefore the first current IPTAT is proportional to the absolute temperature T.

Next, the operation of the second current source 112 in the temperature detection circuit 110 will be described. When the reference signal VREF is input to the non-inverting input terminal of the first operational amplification A1, the input voltage at the inverting input terminal is also VREF. Since this reference voltage VREF is applied as it is to one end side of the second resistor Rofst, the current Iofst flowing through the second resistor Rofst is expressed by Equation 21 when VSS2 is at the ground level. .
Iofst = VREF / R _OFST (Formula 21)

In the current mirror circuit CM1, if the current flowing to the input terminal side is multiplied by M2 and output from the output terminal side, the second current ICONST flowing from the output terminal of the current mirror circuit CM1 is expressed by Equation 22.
ICONST = M2 × Iofst = M2 × (VREF / R _OFST ) (Formula 22)
Since the second current ICONST is constant except for VREF, it can be seen that the second current ICONST is a current dependent on the reference signal VREF.

Next, the operation of the current-voltage conversion circuit 113 in the temperature detection circuit 110 will be described. When the reference signal VREF is input to the non-inverting input terminal of the second operational amplifier A2 constituting the current-voltage conversion circuit 113 and the third current ICONST-IPTAT flows through the second resistor Rg, the operational amplifier A2 The temperature signal VTMP output from the output terminal is expressed by Equation 23.
VTMP = −R _G (ICONST−IPTAT) + VREF (Equation 23)

By substituting the first current IPTAT expressed by Expression 20 and the second current ICONST expressed by Expression 22 into Expression 23, a temperature signal VTMP expressed by Expression 24 (Equation 8) is obtained.

  As can be seen from Equation 24, the temperature signal VTMP is a voltage signal proportional to the reference signal VREF and the absolute temperature T of the semiconductor unit 100 as shown in Equation 1. That is, the temperature signal VTMP is a voltage signal proportional to the absolute temperature T if the reference signal VREF is constant, and a voltage signal proportional to the reference signal VREF if the absolute temperature T is constant.

  As described above, the temperature detection circuit 110 illustrated in FIG. 7 has been described with respect to the case where the anode and the cathode are assigned as the first terminal and the second terminal of the diodes D1 and D2, as described above. Not limited. For example, the following modifications are possible.

  First, as a first modification, the first terminals of the diodes D1 and D2 are set as cathodes, and the second terminal is set as an anode. The first conductivity type transistor is an NMOS transistor, and the second conductivity type transistor is a PMOS transistor. The first terminal of the PMOS transistor and NMOS transistor is the source, the second terminal is the drain, and the control terminal is the gate. The voltage of the first voltage source VSS1 is set lower than the voltage of the second voltage source VSS2.

  As a second modification, the first terminals of the diodes D1 and D2 are anodes and the second terminals are cathodes. The first conductivity type transistor is a pnp transistor, and the second conductivity type transistor is an npn transistor. The first terminal of the pnp transistor and the npn transistor is an emitter, the second terminal is a collector, and the control terminal is a base. The voltage of the first voltage source VSS1 is set higher than the voltage of the second voltage source VSS2.

  Furthermore, as a third modification, the first terminals of the diodes D1 and D2 are the cathodes and the second terminal is the anode. The first conductivity type transistor is an npn transistor, and the second conductivity type transistor is a pnp transistor. The first terminal of the pnp transistor and the npn transistor is an emitter, the second terminal is a collector, and the control terminal is a base. The voltage of the first voltage source VSS1 is set lower than the voltage of the second voltage source VSS2.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In the first embodiment, an example in which the analog processing circuit 121 is used as the signal processing circuit 120 has been described. In the second embodiment, a digital circuit is used. Since the second embodiment is the same as the first embodiment except that the signal processing circuit shown in FIG. 5 in the first embodiment is replaced with the signal processing circuit shown in FIG. 6, the differences will be mainly described. .

FIG. 6 is an internal block diagram of the signal processing circuit 120 in the semiconductor device 1000 shown in FIG. The signal processing circuit 120 is configured by a digital circuit 122 whose operating frequency can be changed according to the setting signal VSET. Since the operating frequency of the digital circuit 122 changes corresponding to the input setting signal VSET, the operating frequency f of the digital circuit 122 is expressed by the following Expression 25 as a function of the setting signal VSET.
f = f (VSET) (Equation 25)

In general, the power consumption P _DIGITAL of the logic circuit is expressed by the following Expression 26.
P _DIGITAL = CV _DD ² fclk + I _Q V _DD (Equation 26)
In Expression 26, C is the capacitance of Ronro circuit, V _DD is a power supply voltage supplied to the logic circuit, fclk is the frequency of operation of the logic circuit, I _Q is the leakage current of the logic circuit .

Therefore, the power consumption (power) P _DIGITAL of the logic circuit (digital circuit 122) can be controlled by the setting signal VSET as can be seen from the following equation 27 in which the above equation 25 is substituted into the equation 26.
P _DIGITAL = CV _DD ² f + I _Q V _DD = CV _DD ² f (VSET) + I _Q V _DD (Equation 27)

Since the temperature change of the semiconductor unit 100 with respect to the power P _ANALOG of the analog circuit 121 shown in the above-described equation 14 is similarly established in the digital circuit 122, the semiconductor unit 100 is heated from time t0 to time t1 due to heat generation of the signal processing circuit 120. The temperature change dT when 100 is heated is expressed by the following Equation 28 (Equation 9).
Here, P _DISP is the amount of heat dissipation per unit time of the semiconductor unit 100.

  Therefore, the determination unit 300 compares the temperature signal VTMP output in accordance with the change in the operating frequency f (VSET) of the digital circuit and the inspection reference value VTEST, and determines whether or not the semiconductor device according to the second embodiment. The apparatus can inspect the temperature detection circuit formed on the semiconductor unit without specially providing a temperature control facility.

  As described above, the first and second embodiments have been described. However, the present invention is not limited to the above-described embodiments as they are, and in the implementation stage, the components are modified and embodied without departing from the scope of the invention. it can. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, you may delete some components of all the components shown by embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 is a block diagram showing a configuration of a semiconductor device according to a first embodiment of the present invention. 5 is a graph showing a relationship between an input value of a setting signal VSET and an output value of a temperature signal VTMP in the first embodiment of the present invention. 6 is a graph showing a relationship between an input value of a reference signal VREF and an output value of a temperature signal VTMP in the first embodiment of the present invention. It is a flowchart which shows the procedure of the test | inspection in the semiconductor device concerning 1st Embodiment of this invention. It is a block diagram which shows the structure of the signal processing circuit of the semiconductor device concerning 1st Embodiment of this invention. It is a block diagram which shows the structure of the signal processing circuit of the semiconductor device concerning 2nd Embodiment of this invention. It is a block diagram which shows the detailed structure of the temperature detection circuit of the semiconductor device concerning 1st Embodiment of this invention. It is a perspective view which shows the conventional heating test | inspection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Semiconductor element 11 ... Mounting stand 12 ... Contactor 13 ... Electrical connection terminal 14 ... Heat distribution means 30 ... Remote temperature sensor 31 ... Temperature controller 100 ... Semiconductor Unit 110 ... temperature detection circuit 111 ... first current source 112 ... second current source 113 ... current-voltage conversion circuit 114 ... difference unit 120 ... signal processing circuit 121 ... analog Circuit 122 ··· Digital circuit 200 ··· Control signal generation means 300 ··· Determination means 400 ··· Inspection reference value holding means A1 ··· First operational amplifier A2 ··· second operational amplifier CM1 ..Current mirror circuit D1 ... first diode D2 ... second diode IPTAT ... first current ICONST ... second current Rd ... first resistor Rofst ... second Resistor Rg · ..Third resistor Q1 ... first transistor (first conductivity type)
Q2 ... Second transistor (first conductivity type)
Q3 ... Third transistor (second conductivity type)
Q4 ... Fourth transistor (second conductivity type)
Q5 ... Fifth transistor (second conductivity type)
Q6 ... Sixth transistor (second conductivity type)
VSS1 ... first voltage source VSS2 ... second voltage source VSET ... setting signal VREF ... reference signal VTMP ... temperature signal

Claims (8)

A first current source that outputs a current whose output changes in response to a temperature change as a first current, and an output current that can be controlled by a reference signal input from the outside and that is substantially constant with respect to the temperature is a second current. A second current source for output, and a current-voltage conversion circuit for inputting a difference between the first current and the second current as a third current, converting the third current into a voltage, and outputting the voltage as a temperature signal. A semiconductor unit comprising a temperature detection circuit and a signal processing circuit which is formed on the same chip as the temperature detection circuit and whose heat generation amount is changed by a setting signal input from the outside, on the same chip;
Control signal generating means for outputting the setting signal and the reference signal;
Inspection reference value holding means for holding the inspection reference value of the semiconductor unit;
A determination means for comparing the temperature signal according to the setting signal and the reference signal with the inspection reference value to determine suitability of the semiconductor unit;
A semiconductor device comprising:   2. The semiconductor device according to claim 1, wherein the signal processing circuit includes an analog circuit whose current consumption changes in accordance with the setting signal input from the outside.   The semiconductor device according to claim 1, wherein the signal processing circuit includes a digital circuit whose operating frequency can be changed according to the setting signal input from the outside. The first current source is connected to a first voltage source in which each first terminal outputs a first voltage, and an area of a pn junction is 1: N (N is an arbitrary positive value). A first resistor having one end connected to the second terminal of the second diode, and a first conductive terminal having a first terminal connected to the second terminal of the first diode; A first transistor of the first type, a first terminal connected to the other end of the first resistor, and a control terminal connected to a second terminal and a control terminal of the first transistor. And a second terminal connected to a control terminal and a second terminal of the first-conductivity-type first transistor. The second transistor is connected to a second power source that outputs a second voltage. A third transistor of two conductivity type, a first terminal connected to the second power source, and a control terminal; A fourth transistor of the second conductivity type commonly connected to a control terminal of the second transistor of the second conductivity type, and a second terminal of which the second terminal is connected to the second terminal of the second transistor; A second conductive type second terminal having a terminal connected to the second voltage source, a control terminal commonly connected to the control terminals of the third and fourth transistors, and a second terminal serving as an output terminal of the first current; 5 transistors,
The second current source includes a first operational amplifier having a non-inverting input terminal connected to the reference signal input terminal, one end connected to the inverting input terminal of the first operational amplifier, and the other end connected to the first operational amplifier. A second resistor connected to the two voltage sources, a control terminal connected to the output terminal of the first operational amplifier, and a first terminal connected to the inverting input terminal of the first operational amplifier. A second conductivity type transistor; and a current mirror circuit having an input terminal connected to the second terminal of the sixth second conductivity type transistor and an output terminal serving as an output terminal of the second current,
The current-voltage conversion circuit has a non-inverting input terminal connected to the reference signal input terminal, an inverting input terminal connected to the first current output terminal and the second current output terminal, and an output terminal connected to the temperature signal. A second operational amplifier serving as an output terminal of the second operational amplifier, a third resistor having one end connected to the inverting input terminal of the second operational amplifier and the other end connected to the output terminal of the second operational amplifier; The semiconductor device according to claim 1, comprising: A first setting signal for setting power consumption is set in a signal processing circuit provided on the same substrate as the temperature detection circuit, and the first temperature signal is held from the temperature detection circuit at this time,
Set a second setting signal for setting power consumption in the signal processing circuit, hold the second temperature signal from the temperature detection circuit at this time,
A semiconductor device inspection method for obtaining a difference value between the first temperature signal and the second temperature signal and determining whether the difference value is within an allowable range of an inspection reference value. A first reference signal is set for a current source provided in the temperature detection circuit, the output current of which can be controlled by the reference signal, and which outputs a substantially constant current with respect to the temperature. Holding a first temperature signal of the detection circuit;
A second reference signal is set for the current source, and the second temperature signal of the temperature detection circuit at this time is held,
A semiconductor device inspection method for obtaining a difference value between the first temperature signal and the second temperature signal and determining whether the difference value is within an allowable range of an inspection reference value. A first current source that outputs, as a first current, a current whose output changes in response to a temperature change;
A second current source capable of controlling an output current by a reference signal input from the outside and outputting a substantially constant current with respect to temperature as a second current; and a difference between the first current and the second current is a third A current-voltage conversion circuit for inputting the current and converting the third current into a voltage and outputting the voltage as a temperature signal;
A temperature detection circuit comprising:
A signal processing circuit which is formed on the same chip as the temperature detection circuit and whose calorific value is changed by a setting signal input from the outside;
A semiconductor unit comprising: A first current source that outputs a first current whose output changes in response to a temperature change; a second current source that outputs a second current that is controllable by a reference signal and that is substantially constant with respect to temperature; The difference between the first current and the second current is input as a third current, converted into a voltage and output as a temperature signal, a temperature detection circuit, and the amount of heat generated is changed by the setting signal. A semiconductor inspection apparatus for a semiconductor unit comprising a signal processing circuit,
Control signal generating means for outputting the setting signal and the reference signal;
Inspection reference value holding means for holding the inspection reference value of the semiconductor unit;
A determination means for comparing the temperature signal according to the setting signal and the reference signal with the inspection reference value to determine suitability of the semiconductor unit;
A semiconductor inspection apparatus comprising: