JP2008008714A - Semiconductor measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device and a semiconductor measuring apparatus which dispense with a Kelvin contact probe in the measurement of current and voltage at an external terminal of a semiconductor device as well as a voltage measuring means. <P>SOLUTION: The semiconductor device 210 comprises: a terminal A to which a load is connected; a current drive transistor M1 for supplying the load with a current; a comparator 211 for comparing a voltage at the terminal A with a reference voltage Vref; and a terminal B connected to the output of the comparator 211. When the terminal A reaches the reference voltage Vref, the signal level of a signal output from the terminal B is changed. The semiconductor measuring apparatus 220 measures the voltage and current values at the terminal A without measuring the voltage at the terminal A, since it reads the current value at the terminal A when the signal level of the signal output from the terminal B changes. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor device and a semiconductor measurement device.

  In a semiconductor device having a built-in current drive transistor that supplies current to a lighting LED (Light Emitting Diode) or a display LED, the specification of the external terminal to which the output of the current drive transistor is connected is, for example, “external terminal When the voltage is a predetermined voltage (for example, 0.4 V), the load current is set to be a predetermined current (for example, 300 mA) or more.

  As such a semiconductor device for supplying current to an LED, for example, an LED driving circuit as shown in FIG. 15 of Japanese Patent Laid-Open No. 2002-319707 (Patent Document 1) is known. FIG. 1 is a diagram showing a conventional LED driving circuit shown in FIG.

  A power supply voltage VDD is applied to the power supply terminal 10 of the LED drive circuit 100. In the constant current generation circuit 15, the error amplification circuit 12 amplifies the difference voltage between the output voltage Vref of the reference voltage circuit 11 and the voltage Va of the resistor 13, and the amplified difference voltage causes the gate voltage of the transistor 14 to be amplified. I have control. An LED 19 and an LED 20 are connected to the external terminal 1 and the external terminal 2 of the LED drive circuit 10, respectively. Here, the same current as the current flowing through the resistor 13 flows through the transistors 14 and 16. In the LED drive circuit 100, the transistors 16, 17, and 18 constituting the current mirror circuit all have the same characteristics, and therefore the same current as the transistor 16 flows through the transistors 17 and 18. The LEDs 19 and 20 are turned on by the current flowing through the transistors 17 and 18.

  In such a semiconductor device, in order to confirm whether the semiconductor device is actually operating as predetermined, current and voltage at an external terminal of the semiconductor device are measured.

  In this measurement, when the terminal voltage is measured while supplying current to the external terminal, the wiring resistance in the measuring device, the wiring resistance of the IC socket, the IC socket and the external terminal existing from the measuring device to the external terminal of the semiconductor device Accurate voltage measurement is difficult due to voltage drop due to contact resistance.

  Therefore, conventionally, the current and voltage at the external terminal of the semiconductor device are measured using a special probe called a Kelvin contact probe. This probe is in a state in which a force probe for supplying a current and a sense probe for detecting a voltage are insulated, and these two probes are brought into contact with an external terminal of the semiconductor device.

  For example, a Kelvin contact probe in the case where the external terminal of the semiconductor device is a lead type IC is described in Japanese Patent Application Laid-Open No. 2004-150981 (Patent Document 2). Patent Document 1 describes an electrical characteristic measuring apparatus and an electrical characteristic measuring method for a semiconductor device in which two measuring contacts are reliably brought into contact with a lead terminal without being affected by the dimensional variation of the lead terminal. .

  Further, for example, the case where the external terminal of the semiconductor device is a solder ball such as a BAG package is described in Japanese Patent Application Laid-Open No. 2005-28335 (Patent Document 3) and Japanese Patent Application Laid-Open No. 2006-38459 (Patent Document 4). . Patent Document 3 describes a two-probe Kelvin probe that can inspect solder balls with two probes without trouble. Patent Document 4 describes a BAG package inspection tool and inspection method for accurately measuring the electrical characteristics of elements housed in a BAG package.

Further, when the Kelvin contact probe as described above is not used in the measurement of the current and voltage at the external terminal of the semiconductor device, the external terminal is divided into two in the semiconductor device, and the current supply terminal and the voltage measurement terminal are made independent. Provided.
JP 2002-319707 A JP 2004-150981 A JP 2005-28335 A JP 2006-38459 A

  However, with the recent miniaturization of IC packages, the shape of external terminals of semiconductor devices has become extremely small. In the measurement using the Kelvin contact probe, since the two electrodes are in contact with one external terminal in an insulated state, the reliability of the contact decreases as the external terminal becomes smaller. There is also a limit to the miniaturization of the Kelvin contact probe itself. Further, even when the external terminal of the semiconductor device is divided into a current supply terminal and a voltage detection terminal, the semiconductor measurement apparatus requires voltage measurement means in addition to the current supply means, and the semiconductor measurement apparatus is complicated and expensive. It will be a thing.

  The present invention has been made to solve these problems in view of the above points, and does not require a Kelvin contact probe and does not require voltage measuring means in measuring current and voltage at an external terminal of a semiconductor device. An object of the present invention is to provide a semiconductor device and a semiconductor measurement device.

  In order to achieve the above object, the semiconductor device and the semiconductor measuring device of the present invention employ the following configurations.

  The semiconductor device of the present invention includes an external terminal for connecting a load, and in the semiconductor device incorporating a current driving transistor for supplying a current to the load, compares the voltage of the external terminal with a reference voltage. The comparator has a configuration and an external terminal connected to the output of the comparator.

  According to this configuration, when the voltage at the external terminal reaches the reference voltage, a signal indicating that can be output.

  In addition, the semiconductor device of the present invention includes a booster circuit that boosts a power supply voltage and supplies power to the load, and the booster circuit can have a configuration in which the boosting rate changes based on the output of the comparator. .

  According to such a configuration, it is not necessary to newly add a comparator, and an increase in circuit scale can be suppressed.

  The semiconductor measuring device of the present invention compares a first external terminal for connecting a load, a current drive transistor for supplying a current to the load, a voltage of the first external terminal and a reference voltage. A semiconductor measuring device according to a semiconductor device having a comparator and a second external terminal connected to the output of the comparator, the variable voltage source supplying a voltage to the first external terminal, and the first A current measurement circuit for measuring a current flowing between the external terminal and the variable voltage source, and reading a current value of the current measurement circuit when a voltage level of the second external terminal changes; did.

  According to such a configuration, since the current value of the current measurement circuit at the time when the voltage level of the second external terminal changes is read, the Kelvin contact probe and the voltage measurement unit are not necessary.

  According to the present invention, it is possible to provide a semiconductor device and a semiconductor measuring device that do not require a Kelvin contact probe and do not require voltage measuring means in measuring current and voltage at an external terminal of the semiconductor device.

  The semiconductor device of the present invention has a built-in current drive transistor for supplying current to the load, and includes a first external terminal for connecting the load, a voltage of the first external terminal, and a reference voltage. And a second external terminal connected to the output of the comparator. The semiconductor device changes the signal level of the signal output from the second external terminal when the first external terminal reaches the reference voltage.

  The semiconductor measurement apparatus of the present invention further includes a variable voltage source that supplies a voltage to the first external terminal, a current measurement circuit that measures a current flowing between the first external terminal and the variable voltage source, When the voltage level of the external terminal changes, the current value of the current measurement circuit is read. Thereby, the semiconductor measuring device can measure the current value when the voltage reaches the reference voltage at the first external terminal of the semiconductor device.

  Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram illustrating an example of a circuit diagram of the semiconductor device 210 and the semiconductor measurement device 220 according to the first embodiment of the present invention.

  The semiconductor device 210 is manufactured so as to satisfy a predetermined electrical characteristic as a specification of the semiconductor device 210, and the semiconductor measurement apparatus 220 measures the electrical characteristic of the semiconductor device 210.

  The semiconductor device 210 will be described below.

  The semiconductor device 210 includes a comparator 211, a current source 212, and NMOS transistors M1 and M2. The semiconductor device 210 includes a terminal A that is a first external terminal and a terminal B that is a second external terminal.

  The reference voltage Vref is applied to the inverting input terminal of the comparator 211, and the non-inverting input terminal is connected to the terminal A. The output terminal of the comparator 211 is connected to the terminal B.

  The NMOS transistors M1 and M2 have their sources grounded and their gates connected in common. The commonly connected gate is connected to the drain of the NMOS transistor M2. A current source 212 is connected to the drain of the NMOS transistor M2, and the drain current of the NMOS transistor M2 is supplied from the current source 212. Note that the current source 212 of this embodiment may have the same configuration as the constant current generation circuit 15 of FIG. 1 described in the background art, for example. The drain of the NMOS transistor M1 is connected to the terminal A.

  Here, the NMOS transistors M1 and M2 constitute a current mirror circuit. Therefore, the drain current of the NMOS transistor M1 becomes a current proportional to the current supplied by the current source 212. For example, when the element size ratio of the NMOS transistor M1 and the NMOS transistor M2 is 1000: 1, the drain current of the NMOS transistor M1 is 1000 times the current supplied from the current source 212.

  The semiconductor device 210 in this embodiment is, for example, an LED driving circuit, and an LED serving as a load may be connected between the terminal A and a power source (not shown) provided outside the semiconductor device 210.

  The electrical characteristics of the semiconductor device 210 are, for example, “when a voltage at the terminal A is a predetermined voltage, a predetermined current is supplied to a load connected to the terminal A”. The predetermined voltage was 0.4 V, and the predetermined current source was 300 mA.

  Next, a semiconductor measurement apparatus will be described.

  The semiconductor measurement device 220 includes a current measurement circuit 221 and a variable voltage source Vt. Further, the semiconductor measuring device 220 includes a terminal a connected to the terminal A of the semiconductor device 210 and a terminal b connected to the terminal B of the semiconductor device 210. The semiconductor measurement device 220 measures the electrical characteristics of the semiconductor device 210 by reading the value of the current flowing through the terminal A when the voltage at the terminal A of the semiconductor device 210 reaches a predetermined voltage.

  The variable voltage source Vt has one end grounded and the other end connected to the terminal a via the voltage measurement circuit 221, and supplies a voltage from the terminal a to the terminal A via the resistor R1. Here, the resistance R <b> 1 represents the total sum of all wiring resistances existing from the semiconductor measuring device 220 to the terminal A of the semiconductor device 210. The resistor R1 of this embodiment includes, for example, the wiring resistance in the semiconductor measuring device 220, the wiring resistance of the IC socket, the contact resistance between the IC socket and the terminal A, and the like.

  The current measurement circuit 221 is a circuit that measures the current value of the current flowing between the variable voltage source Vt and the terminal A, and is connected to the terminal b. The current measurement circuit 221 reads the current value between the variable voltage source Vt and the terminal A based on the signal supplied from the terminal b.

  Next, a procedure for measuring electrical characteristics of the semiconductor device 210 by the semiconductor measuring device 220 will be described with reference to FIG. FIG. 3 is a diagram illustrating an example of electrical characteristics of the semiconductor device 210.

  The reference voltage Vref of the semiconductor device 210 is set to the same voltage as a predetermined voltage determined by specifications. Therefore, since the predetermined voltage in the present embodiment is 0.4V, the reference voltage Vref is set to 0.4V.

  Here, when the voltage of the variable voltage source Vt included in the semiconductor measuring device 220 is gradually increased, the drain current Id of the NMOS transistor M1 increases and the voltage at the terminal A increases as shown in FIG. At this time, the voltage at the terminal A is a voltage obtained by subtracting the voltage drop of the resistor R1 from the variable voltage source Vt.

  Here, when the voltage at the terminal A reaches the reference voltage Vref (0.4 V), the output of the comparator 211 is switched from a low level (hereinafter, L level) to a high level (hereinafter, H level). This H level signal is supplied from the terminal B to the current measuring circuit 221 via the terminal b of the semiconductor measuring device 220.

  In the semiconductor measuring device 220, the current measuring circuit 221 reads the current value of the current flowing between the variable voltage source Vt and the terminal A in response to this H level signal.

  In this way, the semiconductor measuring device 220 can measure the value of the current flowing through the terminal A when the voltage at the terminal A reaches 0.4 V, which is a predetermined voltage. At this time, if the current flowing through the terminal A is 300 mA, which is a predetermined current, it can be said that the semiconductor device 210 satisfies predetermined electrical characteristics. That is, the semiconductor measuring device 220 can measure whether the semiconductor device 210 satisfies predetermined electrical characteristics. Such measurement may be performed, for example, before the semiconductor device 210 is shipped.

  As described above, according to the semiconductor device 210 and the semiconductor measurement device 220 of the present invention, the electrical characteristics of the semiconductor device 210 can be measured without using a Kelvin contact probe. Furthermore, according to the semiconductor device 210 and the semiconductor measuring device 220 of the present invention, the semiconductor measuring device 220 is connected to the terminal A when the voltage at the terminal A of the semiconductor device 210 reaches the reference voltage provided inside the semiconductor device 210. Thus, the voltage and current at the terminal A can be measured without measuring the voltage at the terminal A. Therefore, it is not necessary to provide voltage measuring means in the semiconductor measuring device 220, and a simpler and lower cost semiconductor measuring device can be obtained.

  A second embodiment of the present invention will be described below with reference to FIG. FIG. 4 is a diagram illustrating an example of a circuit diagram of the semiconductor device 210A and the semiconductor measurement device 220 according to the second embodiment of the present invention.

  The second embodiment is different from the first embodiment in that a charge pump circuit 213 is provided in the semiconductor device 210A, the power supply voltage Vin input to the input terminal IN of the charge pump circuit 213, and the charge pump circuit 213. The terminal C to which the output OUT is connected is provided. Therefore, in the description of FIG. 4, only differences from the first embodiment will be described, and components having the same configurations and functions as those of the first embodiment are denoted by the same reference numerals as those in FIG.

  The charge pump circuit 213 includes an input terminal IN, an output terminal OUT, and a boost rate control terminal CTL. The charge pump circuit 213 is a booster circuit that boosts and outputs the power supply voltage Vin applied to the input terminal IN at a predetermined boosting rate. In addition, the charge pump circuit 213 boosts the power supply voltage Vin at a boost rate corresponding to a signal applied to the boost rate control terminal CTL. Then, the boosted voltage is output from the output terminal OUT.

  The output terminal OUT is connected to the terminal C. The voltage supplied to the terminal C is used as a power source supplied to a load (not shown) connected to the terminal C. In this case, the load (not shown) is, for example, an LED or the like, and may be connected between the terminal C and the terminal A.

  The step-up rate control terminal CTL is connected to the output terminal of the comparator 211, and the step-up rate of the charge pump circuit 213 is controlled according to the output of the comparator 211. In this embodiment, the charge pump circuit 213 increases the step-up rate when the voltage at the terminal A is equal to or lower than the reference voltage Vref, that is, when the output of the comparator 211 is at L level. That is, the voltage at the terminal C is higher than the power supply voltage Vin when the voltage at the terminal A is equal to or lower than the reference voltage Vref. The boosting rate of the charge pump circuit 213 and its control will be described later.

  In this way, for example, when an LED or the like serving as a load is connected between the terminal A and the terminal C, the voltage at the terminal A can be increased to the reference voltage Vref, and the semiconductor device 210A is sufficient for the load. A state in which a large current can be supplied. In the charge pump circuit 213, when the voltage at the terminal A reaches the reference voltage Vref, that is, when the output of the comparator 211 becomes H level, the boosting rate may be lowered.

  Here, the boosting rate of the charge pump circuit 213 will be described. In the chiage pump circuit 213, the step-up rate may be selectively set, for example, 1.5 times, 2 times, or the like. In this case, when the signal applied to the boosting rate control terminal CTL is at the L level, the charge pump circuit 213 may set the boosting rate to double and boost the power supply voltage Vin applied to the input terminal IN. . Further, the charge pump circuit 213 sets the boost rate to 1.5 times and boosts the power supply voltage Vin applied to the input terminal IN when the signal applied to the boost rate control terminal CTL is H level. good. The charge pump circuit 213 may be realized using an inductor, a capacitor, or the like.

  The measurement procedure of the electrical characteristics of the semiconductor device 210A by the semiconductor measurement device 220 in this embodiment is the same as that in the first embodiment.

  That is, according to the present embodiment, the booster rate setting comparator 211 of the charge pump circuit 213 can be used also for measuring the electrical characteristics of the semiconductor device 210A. For this reason, in the semiconductor device 210A of the present embodiment, an increase in circuit scale and an increase in cost can be suppressed.

  As described above, according to the embodiments, according to the semiconductor device and the semiconductor measurement device of the present invention, the electrical characteristics of the semiconductor device can be measured without using the Kelvin contact probe. Further, according to the present invention, it is not necessary to provide a voltage measuring means in the semiconductor measuring device, and a simpler and lower cost semiconductor measuring device can be obtained.

  Furthermore, according to the present invention, since the reference voltage Vref for setting the boosting rate of the charge pump circuit and the comparator can be used for measuring the electrical characteristics of the semiconductor device in the semiconductor device, an increase in circuit scale and cost increase can be suppressed.

  As described above, the present invention has been described based on the respective embodiments, but the present invention is not limited to the requirements shown here, such as the shapes given in the above embodiments and combinations with other elements. With respect to these points, the present invention can be changed within a range that does not detract from the gist of the present invention, and can be appropriately determined according to the application form.

  The present invention is applicable to semiconductor devices and semiconductor measurement devices.

It is a figure which shows the conventional LED drive circuit shown by FIG. 15 of patent document 1. FIG. It is a figure which shows an example of the circuit diagram of the semiconductor device 210 and the semiconductor measuring device 220 of Example 1 of this invention. 6 is a diagram illustrating an example of electrical characteristics of a semiconductor device 210. FIG. It is a figure which shows an example of the circuit diagram of 210 A of semiconductor devices and the semiconductor measuring apparatus 220 of Example 2 of this invention.

Explanation of symbols

210, 210A Semiconductor device 211 Comparator 212 Current source 220 Semiconductor measurement device 221 Current measurement circuit A, B, C terminals M1, M2 NMOS transistor Vt Variable voltage source

Claims (3)

In a semiconductor device including an external terminal for connecting a load and incorporating a current drive transistor for supplying a current to the load,
A comparator that compares the voltage of the external terminal with a reference voltage;
A semiconductor device comprising: an external terminal connected to the output of the comparator. Having a booster circuit that boosts a power supply voltage and supplies power to the load;
The semiconductor device according to claim 1, wherein the boosting circuit changes a boosting rate based on an output of the comparator. A first external terminal for connecting a load;
A current drive transistor for supplying current to the load;
A comparator that compares the voltage of the first external terminal with a reference voltage;
A semiconductor measuring device according to a semiconductor device having a second external terminal connected to the output of the comparator,
A variable voltage source for supplying a voltage to the first external terminal;
A current measuring circuit for measuring a current flowing between the first external terminal and the variable voltage source;
A semiconductor measuring apparatus, wherein the current value of the current measuring circuit is read when the voltage level of the second external terminal changes.

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