TW201915500A - Resistance measurement apparatus, substrate inspection apparatus and resistance measurement method capable of easily improving resistance measurement accuracy by a four-terminal measurement method - Google Patents

Abstract

The present invention provides a resistance measurement apparatus, a substrate inspection apparatus and a resistance measurement method. The resistance measurement apparatus includes a first current probe and a second current probe in contact with a chip side electrode; a first detection probe and a second detection probe in contact with an outward electrode; a voltage detection portion for detecting the voltage between the first detection probe and the second detection probe; a first constant current source having a positive electrode connected to the first current probe and a negative electrode connected to the ground for outputting a current with a first current value; a second constant current source having a positive electrode connected to the negative electrode of the first constant current source and the ground and connected in series with the first constant current source, and a negative electrode connected to the second current probe for outputting a current with a second current value substantially the same as the first current value; a grounding probe for connecting the wiring to the ground; and a resistance acquisition portion for acquiring the resistance of the wiring based on the voltage detected by the voltage detection portion.

Description

Resistance measurement device, substrate inspection device, and resistance measurement method

The present invention relates to a resistance measurement device that performs resistance measurement, a substrate inspection device using the same, and a resistance measurement method.

Previously, in order to check a wiring pattern formed on a substrate such as a printed wiring board, the resistance value of the wiring pattern was measured. As the inspection of the wiring pattern, it is needless to say that there is a disconnection inspection, and it is also necessary to detect a defect that does not reach the disconnection such as the width of the wiring pattern becomes thinner or the thickness becomes thinner. In order to detect such a failure that does not reach disconnection, it is necessary to perform high-precision resistance measurement. As such a high-precision resistance measurement method, a resistance measurement device using a four-terminal measurement method is known.

For example, Japanese Unexamined Patent Publication No. 2004-184374 includes a pair of contact probes (P1, P2) for flowing a current for resistance measurement into a wiring pattern of a resistance measurement object, and A pair of contact probes (P3, P4) for measuring the voltage at the resistance measurement site.

According to this structure, the current for resistance measurement does not flow through the contact probes P3 and P4 for voltage measurement. Therefore, the voltage drop caused by the resistance of the contact probes P3 and P4 itself is reduced, and the voltage drop can be increased. Precision resistance measurement. According to FIG. 1 of Japanese Laid-Open Patent Publication No. 2004-184374, the positive-side contact probe P1 for current output is connected to a constant current source, and the negative-side contact probe P2 is connected to a circuit ground.

However, in the resistance measurement device described in Japanese Laid-Open Patent Publication No. 2004-184374, a current for resistance measurement flows through the contact resistance between the contact probe P2 on the negative electrode side and the measurement object M to generate a voltage. This voltage becomes a common mode voltage (common mode noise) with respect to the contact probes P3 and P4 for voltage measurement. The contact resistance Ro of the contact probe P2 can be about 100 Ω. Therefore, if the current i for resistance measurement is set to 20 mA, the common mode voltage Vc becomes Ro × i = 100Ω × 20mA = 2000 mV (see FIG. 7).

On the other hand, when the measurement object is a wiring pattern, the resistance value Rx is about 1 mΩ. Then, if the current i for resistance measurement is 20 mA, the measurement voltage Vm measured by the contact probes P3 and P4 becomes Rx × i = 1mΩ × 20mA = 20 μV = 0.02mV (see FIG. 7).

Then, with respect to the common mode voltage, the measured voltage becomes 20log (measured voltage / common mode voltage) = 20log (0.02 / 2000) = -100dB. Since the contact resistance due to the contact of the contact probe P2 is unstable, the common mode voltage also fluctuates steadily. The measurement voltage becomes a minute voltage of about -100 dB with respect to the common mode voltage. Therefore, the measurement accuracy of the measurement voltage is affected by fluctuations in the common mode voltage and decreases. As a result, there is a disadvantage that the accuracy of the resistance measurement value obtained from the measurement voltage is also reduced.

In addition, as a method of making the common mode voltage zero, a method is conceivable in which, as described in Japanese Laid-Open Publication No. 2007-333598, the common mode voltage is fed back to an inverting amplifier circuit of an operational amplifier, thereby passing Output of the op amp to eliminate common-mode voltage. 8 is an equivalent circuit diagram of the circuit described in FIG. 1 described in Japanese Laid-Open Patent Publication No. 2007-333598. Ro is used to represent the current supply terminal 22, the current supply terminal 23, the voltage measurement terminal 24, and the voltage measurement terminal 25. The parasitic capacitance is represented by Co.

However, in this method, the time delay of the feedback caused by Ro or the parasitic capacitance Co, which is the resistance component of the feedback circuit, and the response of the operational amplifier are slow. Therefore, it is difficult to operate at high speed and eliminate unstable common mode Voltage is not easy.

An object of the present invention is to provide a resistance measurement device, a substrate inspection device, and a resistance measurement method that can easily improve the accuracy of resistance measurement by the four-terminal measurement method.

[Technical means to solve the problem]

The resistance measuring device of the present invention is a resistance measuring device for measuring the resistance of a conductor, and includes: a first current probe and a second current probe for contacting the conductor and flowing a predetermined measurement current; a first detection A probe and a second detection probe are used to contact the conductor and detect a voltage generated in the conductor by the measurement current; a voltage detection unit detects the first detection probe and the second detection probe Voltage between pins; a first constant current source with a positive electrode connected to the first current probe and a negative electrode connected to the ground to output a current of a first current value set in advance; a second constant current source with a positive electrode connected to the first The negative electrode of the constant current source is connected to the ground and connected in series with the first constant current source. The negative electrode is connected to the second current probe and outputs a second current value that is substantially the same as the first current value. A current; a grounding portion that conducts a predetermined portion of the conductor to the ground; and a resistance acquisition portion that acquires the resistance based on a voltage detected by the voltage detection portion.

In addition, the resistance measurement method of the present invention is a resistance measurement method for measuring the resistance of a conductor, and includes: (a) a step of bringing a first current probe and a first detection probe into contact with the conductor; (b) bringing a second current A process in which a probe and a second detection probe contact the conductor at a position separated from a contact position between the first current probe and the first detection probe; (c) detecting the first current probe through the positive electrode; A first constant current source with a negative pole connected to the ground to output a current of a first current value set in advance, and a positive pole connected to the negative pole of the first constant current source and the ground and connected to the first constant current A process in which a source is connected in series, and a second constant current source having a negative electrode connected to the second current probe to output a current having a second current value substantially the same as the first current value; (d) causing the conductor to A step of conducting a predetermined part of the ground to the ground; (e) a step of detecting a voltage between the first detection probe and a second detection probe; and (f) a step detected by the step (e) Voltage to get the Resistive process.

According to these configurations, resistance measurement can be performed by a four-terminal measurement method using the first current probe and the second current probe, and the first detection probe and the second detection probe. Furthermore, as a result of the first constant current source and the second constant current source which are connected in series and whose connection points are set to the ground potential to maintain the output currents of the first current value and the second current value, respectively, The current flowing to the ground from a predetermined portion of the conductor becomes almost zero. As a result, the common-mode voltage becomes almost zero. In addition, since the resistance can be obtained from the measurement voltage measured with the common mode voltage being almost zero, it is easy to improve the measurement accuracy of the resistance. Therefore, it is easy to improve the resistance measurement accuracy by the four-terminal measurement method.

In addition, the ground portion preferably includes a ground probe for contacting the predetermined portion, and the ground probe is connected to the ground.

In addition, it is preferable that the step (d) is a step of bringing a ground probe connected to the ground into contact with the predetermined portion.

According to these structures, the ground probe is brought into contact with a predetermined portion of the conductor, thereby making the conductor conductive to the ground.

The ground portion may be a wiring connecting the second detection probe to the ground.

The second detection probe is connected to the ground, and the step (b) may also serve as the step (d).

According to these structures, the second detection probe can also be used as a ground probe, so there is no need to separately provide a ground probe to contact the conductor.

In addition, it is preferable that a first electrode is provided at one end portion of the conductor, and a second electrode having a larger area than the first electrode is provided at the other end portion of the conductor, and the step (a) is to make the first electrode A step in which a current probe and the first detection probe contact the first electrode, and the step (b) is to contact the second current probe and the second detection probe to the second electrode The step (d) is a step of using the second electrode as the predetermined portion, and contacting the ground probe with the second electrode.

According to this method, two probes are brought into contact with a first electrode having a small area, and three probes are brought into contact with a second electrode having a large area. Therefore, each probe is easily brought into contact with the first electrode and the second electrode.

A substrate inspection device according to the present invention includes the resistance measurement device and a substrate inspection unit that inspects the wiring formed as the conductor on a substrate based on the resistance measured by the resistance measurement device.

According to this configuration, the wiring formed on the substrate can be inspected based on the resistance measured by the resistance measuring device.

A resistance measurement device, a substrate inspection device, and a resistance measurement method having such a structure can easily improve the resistance measurement accuracy by the four-terminal measurement method.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (First Embodiment)

FIG. 1 is a block diagram showing an example of a configuration of a substrate inspection apparatus 1 using a resistance measurement apparatus according to a first embodiment of the present invention. In addition, the structures denoted by the same symbol in each drawing represent the same structure, and descriptions thereof are omitted.

The substrate inspection device 1 (resistance measurement device) shown in FIG. 1 includes a constant current source CS1 (first constant current source), a constant current source CS2 (second constant current source), a voltage detection unit 4, and a current probe Pc1. (First current probe), current probe Pc2 (second current probe), detection probe Pv1 (first detection probe), detection probe Pv2 (second detection probe), and ground probe PG (ground Section), the scanner 6, and the control section 5.

FIG. 1 shows a state where each of the probes of the substrate inspection apparatus 1 has come into contact with the substrate A to be inspected. The substrate inspection apparatus 1 performs resistance measurement by a so-called four-terminal measurement method. The portion after removing the substrate inspection unit 52 described later from the substrate inspection device 1 corresponds to an example of a resistance measurement device.

The substrate of the inspection object may be, for example, a package substrate for semiconductor packaging, an interposer substrate, a film carrier, a printed wiring substrate, a glass epoxy substrate, a flexible substrate, or a ceramic multilayer wiring substrate. It can be an electrode plate for a display such as a liquid crystal display or an electro-luminescence (EL) display, or a transparent conductive plate for a touch panel, or a semiconductor wafer, a semiconductor wafer, or a chip size package. CSP) and other semiconductor substrates.

The substrate of the inspection object may be a component-embedded substrate (embedded substrate) in which electronic components such as semiconductor wafers are embedded. The inspection object is not limited to a substrate, and may be an electronic component such as a semiconductor wafer. Inspection points such as a wiring pattern, a pad, a land, a solder bump, and a terminal are formed in a substrate or an electronic component of an inspection object.

FIG. 1 illustrates a cross-sectional view of a plug-in substrate for semiconductor packaging of a substrate A as an inspection target. A plurality of wafer-side electrodes A1 (first electrodes) connected to a semiconductor wafer are formed on one surface of the substrate A. The interval between the plurality of wafer-side electrodes A1 is set to a narrow pitch with reference to the fine electrode pitch of the semiconductor wafer, and the size of the wafer-side electrode A1 is also set to be small. On the other surface of the substrate A, a plurality of outward electrodes A2 (second electrodes) for connecting the semiconductor wafer to the outside are formed.

The plurality of outward-facing electrodes A2 is, for example, a ball grid that is arranged in a grid shape and is connected to the outside through solder balls. In order to facilitate the wiring with the outside, the interval between the plurality of outward-facing electrodes A2 is wider than the interval between the wafer-side electrodes A1, and the size of the outward-facing electrode A2 is also larger than that of the wafer-side electrode A1.

Each wafer-side electrode A1 and each outward-facing electrode A2 are electrically connected to each other through a wiring A3 (conductor) formed so as to penetrate the thickness direction of the substrate A. The substrate inspection apparatus 1 measures and inspects the resistance value Rx of each wiring A3. The wiring A3 corresponds to an example of a conductor, the wafer-side electrode A1 corresponds to one end portion of the wiring A3, and the outward electrode A2 corresponds to the other end portion of the wiring A3.

The current probe Pc1, the current probe Pc2, the detection probe Pv1, the detection probe Pv2, and the ground probe PG are configured as, for example, inspection jigs detachable from the substrate inspection device 1. Hereinafter, the current probe Pc1, the current probe Pc2, the detection probe Pv1, the detection probe Pv2, and the ground probe PG may be described only as a probe Pc1, a probe Pc2, a probe Pv1, a probe Pv2, and a probe. Needle PG.

The probe Pc1, the probe Pc2, the probe Pv1, the probe Pv2, and the probe PG are, for example, elastic (flexible) linear contactors having a diameter of about 100 μm to 200 μm. The current probe Pc1, the current probe Pc2, the detection probe Pv1, and the detection probe Pv2 are formed of a metal such as tungsten, high-speed steel (SKH), beryllium copper (Be-Cu), and other electrical conductors.

The front ends of the current probe Pc1 and the detection probe Pv1 contact the wafer-side electrode A1 of the substrate A. The tips of the current probe Pc2, the detection probe Pv2, and the ground probe PG contact the outward-facing electrode A2 at a position spaced from the wafer-side electrode A1. If the probes are brought into contact with the wafer-side electrode A1 and the outward electrode A2 in this way, two probes are brought into contact with a small, narrow-pitch wafer-side electrode A1, and the three probes are brought into contact with a wider, wider-pitch outward than the wafer-side electrode A1. Electrode A2. Therefore, each probe is easily brought into contact with the wafer-side electrode A1 and the outward electrode A2.

In FIG. 1, the illustration is simplified and one probe Pc1, one probe Pc2, one probe Pv1, one probe Pv2, and one probe PG are respectively described, but there are several hundred to several thousand checkpoints set on one substrate. In some cases, the probes Pc1, Pc2, probe Pv1, probe Pv2, and probe PG may be provided in a number of several hundred to several thousand corresponding to such a large number of checkpoints.

The scanner 6 is the connection relationship between the current probe Pc1, the current probe Pc2 and the constant current source CS1, the constant current source CS2, and the connection relationship between the detection probe Pv1, the detection probe Pv2, and the voltage detection unit 4, And a switching circuit that switches the connection relationship between the ground probe PG and the ground. The scanner 6 includes, for example, a plurality of switches including a switch 61, a switch 62, a switch 63, a switch 64, and a switch 65. The switches such as the switch 61, the switch 62, the switch 63, the switch 64, and the switch 65 are, for example, semiconductor switches such as transistors, or various switching elements such as relay switches. Each switch is turned on and off in response to a control signal from the control unit 5, for example.

The constant current source CS1 and the constant current source CS2 are constant current circuits that flow a fixed current, and a constant current for measurement flows into the wiring A3. As the constant current source CS1 and the constant current source CS2, for example, various circuits known as a constant current circuit using a transistor or a Zener diode, a current mirror circuit, or the like can be used, or a switching power supply can be used. Circuit, etc.

The positive electrode (+) of the constant current source CS1 is connected to the current probe Pc1 via the switch 61, and the negative electrode (-) is connected to the ground GND. The constant current source CS1 outputs a current of a first current value I ₁ set in advance from the positive electrode (+) to the current probe Pc1. The first current value I _{1 is} set to about 20 mA, for example.

The positive electrode (+) of the constant current source CS2 is connected to the negative electrode (-) of the constant current source CS1 and the ground GND and is connected in series with the constant current source CS1, and its negative electrode (-) is connected to the current probe Pc2 via the switch 62. The constant current source CS2 outputs a current having a second current value I ₂ that is substantially the same as the first current value I ₁ from the positive electrode (+) thereof to the constant current source CS ₁ . Here, the term "substantially the same" means that even if there is a difference in the degree due to manufacturing variations, current control accuracy, or the like of the constant current source CS1, the constant current source CS2, the same meaning is considered.

The ground GND is the circuit ground of the substrate inspection device 1. The ground GND may be a frame ground (ground ground) of the substrate inspection device 1, but a circuit ground is more preferable.

When the switch 61, switch 62, switch 63, switch 64, and switch 65 are turned on by the control unit 5, a constant current source CS1, switch 61, current probe Pc1, chip-side electrode A1, and wiring A3 are formed from the ground GND. Current loop of measurement current I for external electrode A2, current probe Pc2, switch 62, and constant current source CS2 to return to ground GND.

The voltage detection unit 4 measures the voltage between the detection probe Pv1 and the detection probe Pv2. The voltage detection unit 4 is configured using, for example, an analog-to-digital converter, a voltage dividing resistor, or the like. The positive (+) terminal of the voltage detection unit 4 is connected to the detection probe Pv1 via the switch 63, and the negative (−) terminal of the voltage detection unit 4 is connected to the detection probe Pv2 via the switch 64. Accordingly, the voltage detection unit 4 measures the voltage between the detection probe Pv1 and the detection probe Pv2 selected by the scanner 6 as the measurement voltage Vs, and outputs data indicating the measurement voltage Vs to the control unit 5.

The control unit 5 is, for example, a so-called microcomputer including a central processing unit (CPU) that executes predetermined arithmetic processing, a random access memory (RAM) that temporarily stores data, A non-volatile storage device that stores predetermined control programs and the like, and their peripheral circuits. The control unit 5 functions as the resistance acquisition unit 51 and the substrate inspection unit 52 by executing a predetermined control program.

The resistance acquisition unit 51 calculates the resistance value Rx of the wiring A3 of the measurement object based on the measurement voltage Vs detected by the voltage detection unit 4. Specifically, the resistance value Rx is calculated from the current value Is of the measurement current I = the first current value I ₁ ≒ the second current value I ₂ and the measurement voltage Vs using the following formula (1). Resistance value Rx = Vs / Is (1)

The substrate inspection device 1 (resistance measurement device) includes a current measurement unit that measures the current value Is of the current actually flowing through the wiring A3, and the resistance acquisition unit 51 may use the current value Is and the measurement voltage measured by the current measurement unit. Vs to calculate the resistance value Rx. If the current value Is is a fixed value, the resistance value Rx is proportional to the measurement voltage Vs. Therefore, the resistance acquisition unit 51 may obtain the resistance value Rx as information indicating the resistance value Rx without calculating the resistance value Rx using the formula (1).

The substrate inspection unit 52 inspects the wiring A3 as a conductor based on the resistance value Rx acquired by the resistance acquisition unit 51. Specifically, the substrate inspection unit 52 compares the reference value Rref stored in the storage unit in advance with the resistance value Rx. When the resistance value Rx is less than the reference value Rref, the wiring A3 is judged to be a good product. When the reference value Rref is greater than or equal to, the wiring A3 is determined to be defective.

FIG. 2 is an explanatory diagram showing an equivalent circuit of the substrate inspection device 1 and the substrate A in a state where the switches 61, 62, 63, 64, and 65 are turned on. In FIG. 2, the resistance Rc1 indicates the contact resistance of the current probe Pc1 and the wafer-side electrode A1 and the resistance of the switch 61 and the like, the resistance Rc2 indicates the contact resistance of the current probe Pc2 and the outward electrode A2 and the resistance of the switch 62 and the like, and the resistance Rv1 Represents the contact resistance of the detection probe Pv1 and the wafer-side electrode A1 and the resistance of the switch 63, etc., the resistance Rv2 indicates the contact resistance of the detection probe Pv2 and the outward electrode A2, and the resistance of the switch 64, etc., and the resistance RG indicates the ground probe PG and the outward The contact resistance of the electrode A2 and the resistance of the switch 65 and the like. In addition, the parasitic capacitance generated in the equivalent circuit shown in FIG. 2 is represented by a capacitor Cp.

Hereinafter, the operation of the substrate inspection apparatus 1 will be described based on the equivalent circuit shown in FIG. 2. First, as a result of the constant current source CS1 outputting a current of a first current value I ₁ and the constant current source CS2 outputting a current of a second current value I ₂ , a current I for measuring the current value Is flows in the wiring A3. At this time, the voltage detection unit 4 passes through the current probe Pc1 and the current probe Pc2 which are different from the measurement current I, and the detection probe Pv1 and the detection probe Pv2 are different from each other. The mode voltage is measured as the measurement voltage Vs, and the measurement voltage Vs is transmitted from the voltage detection unit 4 to the resistance acquisition unit 51.

In this case, since the current does not flow through the resistors Rv1 and Rv2, the resistance acquisition unit 51 obtains the resistance value Rx from the measurement voltage Vs from which the resistances Rv1 and Rv2 have been excluded, which is in contrast to the so-called two-terminal measurement method. Ratio for high-precision resistance measurement.

Next, the common-mode voltage will be described. Since the constant current source CS2 and the resistor Rc2 are connected in series, the current of the second current value I ₂ will first flow through the resistor Rc2 first. When the resistance value of the resistance Rc2 is set to the resistance value Rc ₂ , a voltage of Rc ₂ × I ₂ is generated in the resistance Rc2. The constant current circuit usually has a high internal resistance. The negative (-) potential of the constant current power supply CS2 is not the same as the ground potential. Therefore, the voltage generated in the resistor Rc2 is not directly applied to the resistor RG. However, at least a part of the voltage generated in the resistor Rc2 is applied to the resistor RG, and a current of the current value I ₃ is to flow in the resistor RG.

Here, a relationship shown by the following formulas (2) and (3) exists between the first current value I ₁ , the second current value I ₂ , and the current value I ₃ .

I ₁ = I ₂ + I ₃ (2)

I ₁ ≒ I ₂ (3)

Here, since the constant current source CS1 is a constant current source, the first current value I ₁ is a fixed value. Since the first current value I ₁ ≒ the second current value I ₂ , if the current of the current value I ₃ is measured from If the current I is shunted into the resistor RG, the current supplied to the negative electrode (-) of the constant current source CS2 is insufficient relative to the second current value I ₂ , and the constant current source CS2 cannot flow a current of the second current value I ₂ . .

Here, since the constant current source CS2 is also a constant current source, it is intended to forcefully flow out the second current value I ₂ . At this time, because the positive electrode (+) of the constant current source CS2 is connected to the ground, the potential of the second current value I ₂ is forced to flow out by the constant current source CS2, and the potential of the negative electrode (-) of the constant current source CS2 decreases until the The negative electrode (-) of the constant current source CS2 is supplied with a current of the second current value I ₂ . The state in which a current of a second current value I ₂ (≒ first current value I ₁ ) is supplied to the negative electrode (-) of the constant current source CS2 is a state where the current value I ₃ ≒ 0 is obtained according to formula (2).

The value of the current I ₃ ≒ 0 flowing in the resistor RG means that the potentials at both ends of the resistor RG become approximately equal. Since one end of the resistor RG is connected to the ground, the other end of the resistor RG, that is, the potential of the outward-facing electrode A2 shown in FIG. 2 becomes approximately a ground potential. Since the detection probe Pv2 is contacting the outward-facing electrode A2, the potential of the outward-facing electrode A2 becomes approximately the ground potential, that is, the common mode voltage applied to the voltage detection section 4 becomes approximately zero.

As described above, the constant current source CS1 and the constant current source CS2, which are connected in series and whose connection points are set to the ground potential, respectively want to maintain the output currents of the first current value I ₁ and the second current value I ₂ . The action is performed within a moment of the response time of the constant current source CS1 and the constant current source CS2, and the common mode voltage becomes approximately zero.

As described above, in the background art, the measurement accuracy of the measurement voltage is affected by fluctuations in the common-mode voltage and decreases. On the other hand, the substrate inspection device 1 can make the common mode voltage substantially zero, and therefore can improve the measurement accuracy of the resistance value Rx as a measurement object compared to the background art. Therefore, it is easy to improve the resistance measurement accuracy by the four-terminal measurement method.

3 is a flowchart showing an example of a resistance measurement method according to an embodiment of the present invention. First, the resistance acquisition unit 51 moves the current probe Pc1 and the detection probe Pv1 by omitting the driving mechanism shown in the figure, and contacts the wafer-side electrode A1 (step S1: step (a)). Next, the resistance acquisition unit 51 moves the current probe Pc2, the detection probe Pv2, and the ground probe PG by omitting the illustrated driving mechanism, and contacts the outward electrode A2 (step S2: step (b), step (d)). ).

Then, the resistance acquisition unit 51 turns on the switches 61, 62, 63, 64, and 65 (step S3). Step S2 and step S3 correspond to an example of step (d). Then, the resistance acquisition unit 51 outputs a current of the first current value I ₁ (= Is) through the constant current source CS1, and outputs a current of the second current value I ₂ (≒ I ₁ ) through the constant current source CS2 (step S4: Step (c)).

Next, the voltage detection unit 4 measures the voltage between the detection probe Pv1 and the detection probe Pv2 as the measurement voltage Vs (step S5: step (e)). Then, the resistance acquisition unit 51 calculates the resistance value Rx of the measurement object based on the formula (1) (step S6), and displays the resistance value Rx by, for example, a display device in which a drawing is omitted.

As described above, the resistance value Rx can be calculated based on the measurement voltage Vs measured in a state where the common mode voltage is substantially zero through the processes of steps S1 to S6, and therefore the accuracy of the calculation of the resistance value Rx is easily improved. Therefore, it is easy to improve the resistance measurement accuracy by the four-terminal measurement method.

Then, the resistance value Rx is compared with the reference value Rref by the substrate inspection unit 52 (step S7). When the resistance value Rx is less than the reference value Rref (YES in step S7), the substrate inspection unit 52 determines that the wiring A3 is good (step S8). On the other hand, if the resistance value Rx is equal to or greater than the reference value Rref (NO in step S7), the substrate inspection unit 52 determines that the wiring A3 is defective (step S9), and displays it by, for example, omitting the display device of the drawing As a result of these determinations, the process ends.

For other wirings A3, the same processing as in steps S1 to S9 is also repeated, so that the resistance values Rx of all the wirings A3 of the measurement object in the substrate A can be measured, and whether the substrate A is a good product can be checked.

In addition, since the common-mode voltage is noise, making the common-mode voltage approximately zero is equivalent to increasing the signal / noise (S / N) ratio of the measurement voltage Vs. Therefore, according to the substrate inspection apparatus 1 and the resistance measurement method, the S / N ratio can be improved and the measurement accuracy of the resistance value Rx according to the measurement voltage Vs can be improved.

As a method of increasing the S / N ratio of the measurement voltage Vs, it is conceivable to increase the current value of the measurement current to increase the measurement voltage as a signal component. However, if the current value of the measurement current is increased in the circuit described in Japanese Laid-Open Patent Publication No. 2004-184374, a contact resistance between the contact probe P2 on the negative side and the measurement object M is generated. As a result, the common-mode voltage increases. Therefore, it is not easy to improve the S / N ratio in the circuit described in FIG. 1 of Japanese Laid-Open Patent Publication No. 2004-184374.

On the other hand, according to the substrate inspection apparatus 1, the S / N ratio of the measurement voltage Vs can be increased by making the common mode voltage approximately zero. Therefore, it is easy to increase the S / N ratio and improve the measurement accuracy of the resistance value Rx.

In addition, in the circuit described in FIG. 1 of Japanese Laid-Open Patent Publication No. 2004-184374, when a resistance measurement is performed on a measurement object such as a built-in substrate or an electronic component, if a common-mode voltage is generated during the measurement, then A potential difference may occur between the measurement object and the substrate inspection device with respect to an electronic component such as a semiconductor element incorporated in the component-embedded substrate due to a charge relationship with a parasitic capacitance of the measurement object. In this case, there is a concern that the voltage difference or the current stress is applied to the electronic component due to the potential difference, and the electronic component is damaged.

FIG. 4 is an explanatory diagram showing the connection of the substrate inspection apparatus 1 when an IC (Integrated Circuit) 100 including the signal terminals P1 to Pn, the power terminal Vcc, and the ground terminal GND is inspected. As described above, in the resistance measurement using the previous two-terminal method or the four-terminal method without using two constant current sources (CS1, CS2) and the ground probe PG, the current probe Pc1, the current probe Pc2, or A common-mode voltage is applied to the terminals of the IC to which the detection probes Pv1 and Pv2 are in contact. In the IC 100, there is a parasitic capacitance Co generated by the IC 100 itself or external wiring. Therefore, a common mode voltage applied to a terminal of the IC is wound into the parasitic capacitance Co, and stress is applied to the IC 100 or damage is caused.

In this case, it is conceivable to gradually increase the current for measurement to gradually increase the common-mode voltage, thereby gradually charging the parasitic capacitance by the common-mode voltage, thereby reducing the current flowing into the parasitic capacitance. Value and remove the potential difference between the measurement object and the substrate inspection device. Accordingly, it is considered that damage to the electronic components can be prevented. However, in the method of gradually increasing the parasitic capacitance by gradually increasing the measurement current, it is necessary to wait for the voltage measurement before the parasitic capacitance of the measurement object is charged by the common mode voltage and the potential difference disappears, and the time required for the measurement increases. Big.

However, according to the substrate inspection apparatus 1, since the common mode voltage becomes almost zero, it is not necessary to wait for the voltage measurement before the parasitic capacitance of the measurement object is charged by the common mode voltage and the potential difference disappears. As a result, it is easy to shorten the resistance measurement time and the inspection time.

In addition, as a method of making the common-mode voltage zero, a method is conceivable in which the common-mode voltage is fed back to an inverting amplifier circuit of an operational amplifier as described in Japanese Laid-Open Patent Publication No. 2007-333598. The common-mode voltage is eliminated by the output of the operational amplifier. However, in this method, the time delay of the feedback caused by the resistance component or parasitic capacitance of the feedback circuit, the response of the operational amplifier is slow, etc., so it is not easy to eliminate the unstable common mode voltage.

On the other hand, according to the substrate inspection apparatus 1, the constant current source CS1 and the constant current source CS2, which are connected in series and whose connection points are set to the ground potential, are to maintain the first current value I ₁ and the second current value I _{2 respectively} . As a result of the output current, the common-mode voltage becomes approximately zero, so it is easy to reduce the common-mode voltage.

In addition, the substrate inspection device 1 may be a resistance measurement device that does not include the substrate inspection unit 52, or may not perform steps S7 to S9. The scanner 6 may not be provided. In addition, the ground probe PG is not necessarily limited to an example of contacting the outward-facing electrode A2, that is, the end on the negative electrode side of the wiring A3 (conductor). The ground probe PG preferably contacts one end on the negative electrode side of the wiring A3, but may also contact the wafer-side electrode A1, which is one end on the positive electrode side of the wiring A3, or may contact the middle portion of the wiring A3.

The current probe Pc1, the current probe Pc2, the detection probe Pv1, and the detection probe Pv2 are not necessarily limited to examples in which both ends of the wiring A3 (conductor) in contact with the measurement target are contacted. Even when the current probe Pc1, the current probe Pc2, the detection probe Pv1, and the detection probe Pv2 are in contact with the middle portion of the measurement object, the contact portion of the current probe Pc1 and the detection probe Pv1 and the current detection can be measured. The resistance value between the contact portion of the needle Pc2 and the detection probe Pv2. (Second Embodiment)

Next, a substrate inspection device 1a using a resistance measurement device according to a second embodiment of the present invention will be described. FIG. 5 is a block diagram showing an example of a configuration of a substrate inspection apparatus 1 a using a resistance measurement device according to a second embodiment of the present invention. FIG. 6 is an explanatory diagram showing an equivalent circuit of the substrate inspection apparatus 1 a and the substrate A shown in FIG. 5. The substrate inspection apparatus 1 a shown in FIGS. 5 and 6 is different from the substrate inspection apparatus 1 shown in FIG. 1 in the following points.

That is, the substrate inspection apparatus 1 a shown in FIGS. 5 and 6 differs from the substrate inspection apparatus 1 in that although the ground probe PG and the switch 65 are not provided, the negative (−) terminal of the voltage detection unit 4 is connected to the ground. In this case, the wiring connecting the negative (-) terminal of the voltage detection section 4 to the ground corresponds to an example of the ground section. In addition, the ground probe PG is not brought into contact with the outward electrode A2 in step S2, and the switch 65 is not turned on in step S3.

The other structures are the same as those of the substrate inspection apparatus 1 shown in FIG. 1, and thus descriptions thereof are omitted. As in the case of the substrate inspection device 1, the substrate inspection device 1 a is configured to maintain a first current value I ₁ , a constant current source CS1 and a constant current source CS2 which are connected in series and whose connection points are set to the ground potential. The output current of the second current value I ₂ . As a result, the current value I ₃ flowing in the resistor Rv2 becomes approximately zero, and the common mode voltage becomes approximately zero. Therefore, it is easy to reduce the common mode voltage.

In addition, according to the substrate inspection apparatus 1 a, it is not necessary to separately provide a ground probe PG, and thus it is easy to reduce costs compared with the substrate inspection apparatus 1. In addition, since the number of probes of the contact wiring A3 is only two, it is easier to make the probes contact than the substrate inspection apparatus 1 in which three probes must contact the wiring A3.

However, although the first current value I ₁ and the second current value I ₂ of the constant current source CS1 and the constant current source CS2 are substantially the same (I ₁ ≒ I ₂ ), there are some problems caused by the constant current source CS1 and the constant current source CS2. There is a slight concern that manufacturing variations or current control accuracy may be poor. When a difference occurs between the first current value I ₁ and the second current value I ₂ , a current corresponding to the difference current value I ₃ flows in the resistor Rv2 shown in FIG. 6. In this case, if the resistance value of the resistance Rv2 is set to the resistance value Rv ₂ , a voltage of Rv ₂ × I ₃ is generated in the resistance Rv2. Since this voltage is included in the measurement voltage Vs measured by the voltage detection unit 4, a measurement error of the measurement voltage Vs occurs.

On the other hand, in the substrate inspection apparatus 1 shown in FIG. 2, when a difference occurs between the first current value I ₁ and the second current value I ₂ , a current corresponding to the difference current value I ₃ It flows in the resistor RG. In the substrate inspection apparatus 1, a voltage generated by a current flowing through the resistor RG is not included in the measurement voltage Vs. Therefore, the substrate inspection apparatus 1 is more preferable than the substrate inspection apparatus 1a in that a measurement accuracy error due to a difference between the first current value I ₁ and the second current value I ₂ is difficult to occur.

1. 1a‧‧‧ substrate inspection device (resistance measurement device)

4‧‧‧Voltage detection department

5‧‧‧Control Department

6‧‧‧ Scanner

22, 23‧‧‧ Current supply terminal

24, 25‧‧‧Voltage measurement terminal

51‧‧‧Resistance acquisition section

52‧‧‧Substrate Inspection Department

61, 62, 63, 64, 65‧‧‧ switches

100‧‧‧IC

A‧‧‧ substrate

A1‧‧‧ Wafer-side electrode (first electrode)

A2‧‧‧ outward electrode (second electrode)

A3‧‧‧Wiring (Conductor)

Co‧‧‧ Parasitic capacitance

Cp‧‧‧Capacitor

CS1‧‧‧constant current source (first constant current source)

CS2‧‧‧constant current source (second constant current source)

D‧‧‧ Diode

GND‧‧‧ ground / ground terminal

I‧‧‧ current for measurement

I ₁ ‧‧‧ the first current value

I ₂ ‧‧‧ second current value

Is, I ₃ ‧‧‧ current value

P1 ～ Pn‧‧‧Signal terminals

Pc1, Pc2, Pv1, Pv2, PG‧‧‧ probes

Rc1, Rc2, Rv1, Rv2, RG‧‧‧ resistance

Rc ₂ , Rv ₂ , Rx‧‧‧ resistance

Rref‧‧‧ benchmark

Ro‧‧‧contact resistance

Vc‧‧‧ Common Mode Voltage

Vm, Vs‧‧‧Measured voltage

Vcc‧‧‧ Power Terminal

S1 ～ S9‧‧‧‧ steps

FIG. 1 is a block diagram showing an example of a configuration of a substrate inspection apparatus using a resistance measurement apparatus according to a first embodiment of the present invention. FIG. 2 is an explanatory diagram showing an equivalent circuit of a substrate inspection device and a substrate shown in FIG. 1. 3 is a flowchart showing an example of a resistance measurement method according to an embodiment of the present invention. FIG. 4 is an explanatory diagram showing a connection of a substrate inspection device when inspecting an integrated circuit (IC). 5 is a block diagram showing an example of a configuration of a substrate inspection apparatus using a resistance measurement apparatus according to a second embodiment of the present invention. FIG. 6 is an explanatory diagram showing an equivalent circuit of a substrate inspection device and a substrate shown in FIG. 5. FIG. 7 is an explanatory diagram for explaining a common mode voltage of the background art. FIG. 8 is an equivalent circuit diagram of the circuit described in FIG. 1 of Japanese Laid-Open Patent Publication No. 2007-333598.

Claims (8)

A resistance measuring device for measuring the resistance of a conductor. The resistance measuring device includes: a first current probe and a second current probe, configured to contact the conductor and flow out a predetermined current for measurement; a first detection A probe and a second detection probe are used to contact the conductor and detect a voltage generated in the conductor by the measurement current; a voltage detection unit detects the first detection probe and the second Detecting the voltage between the probes; a first constant current source, a positive electrode of the first constant current source is connected to the first current probe, a negative electrode of the first constant current source is connected to the ground, and a preset first A current of a current value; a second constant current source, the positive electrode of the second constant current source is connected to the negative electrode of the first constant current source and the ground, and is connected in series with the first constant current source, the A negative electrode of a second constant current source is connected to the second current probe, and outputs a current of a second current value that is substantially the same as the first current value; a grounding portion connects a predetermined portion of the conductor to Ground conductive; and a resistance acquisition unit to acquire the resistance according to a voltage by the voltage detecting unit detected. The resistance measuring device according to item 1 of the scope of patent application, wherein the ground portion includes a ground probe for contacting the predetermined portion, and the ground probe is connected to the ground. The resistance measuring device according to item 1 of the scope of patent application, wherein the ground portion is a wiring connecting the second detection probe to the ground. A substrate inspection device, comprising: the resistance measurement device according to any one of claims 1 to 3; and a substrate inspection unit that performs as the said resistance measurement device formed on a substrate based on a resistance measured by the resistance measurement device. Inspection of conductor wiring. A resistance measurement method is a resistance measurement method for measuring the resistance of a conductor, the resistance measurement method includes: (a) a step of bringing a first current probe and a first detection probe into contact with the conductor; (b) bringing a first A process in which two current probes and a second detection probe contact the conductor at a position separated from the contact positions of the first current probe and the first detection probe; (c) the positive electrode is connected to the first detection probe; A current probe is connected, a first constant current source with a negative pole connected to the ground to output a current of a first current value set in advance, and a positive pole is connected to the negative pole of the first constant current source and the ground and is connected to the first A process in which a constant current source is connected in series, and a second constant current source having a negative electrode connected to the second current probe to output a current having a second current value substantially the same as the first current value; (d) making the A step of conducting a predetermined portion of the conductor to the ground; (e) a step of detecting a voltage between the first detection probe and the second detection probe; and (f) according to (e) Inspection by process To the step of obtaining the resistance. The resistance measurement method according to item 5 of the scope of patent application, wherein the step (d) is a step of bringing a ground probe connected to the ground to the predetermined portion. The resistance measurement method according to item 5 of the scope of the patent application, wherein the second detection probe is connected to the ground, and the step (b) is also the step (d). The resistance measurement method according to item 6 of the scope of patent application, wherein a first electrode is provided at one end portion of the conductor, and a second electrode having a larger area than the first electrode is provided at the other end portion of the conductor. The step (a) is a step of bringing the first current probe and the first detection probe into contact with the first electrode, and the step (b) is a step of bringing the second current probe A step of contacting the second electrode with the second detection probe, and the step (d) is the step of using the second electrode as the predetermined portion, and contacting the ground probe with the second electrode; Procedure.