Inspection apparatus and inspection method

Abstract

Provided is an inspection device and an inspection method that can easily correct variations in electrostatic capacitance due to variations in manufacture of substrates. A substrate inspection device 1 for inspecting a plurality of substrates A each having a wiring P and a reference wiring B formed thereon comprises: a measurement unit 22 that measures electrostatic capacitance of the wiring P and the reference wiring B of each substrate A as measurement capacitances C; an average capacitance calculation unit 23 that calculates, as an average capacitance Cav, an average value of the measurement capacitances C obtained from the reference wirings B provided as the same wiring in terms of design; and a capacitance correction unit 24 that calculates a corrected capacitance Cc, which is a corrected value of the measurement capacitance C of a target wiring P being inspected on a target substrate Ai, which is one of the plurality of substrates A, wherein the capacitance correction unit 24 calculates the corrected capacitance Cc by multiplying the ratio of the average capacitance Cav to the measurement capacitance C of the wiring of the target substrate Ai by the measurement capacitance C of the target wiring P.

Description

Technical Field

[0001] The present invention relates to an inspection apparatus and an inspection method for inspecting a substrate.

Background Art

[0002] Conventionally, a circuit board inspection method is known in which the capacitance between counter electrodes between a plurality of conductor patterns and a reference electrode on a circuit board to be measured is measured, and the circuit board is inspected based on the measured capacitance between the counter electrodes (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, the capacitance of a wiring also changes depending on the opposing area of the wiring and the like. Therefore, due to manufacturing variations in the substrate, if the width of the wiring, the thickness of the insulating layer, etc. vary, the capacitance of the wiring will also vary.

[0005] An object of the present invention is to provide an inspection apparatus and an inspection method that can easily correct variations in capacitance due to manufacturing variations in a substrate.

Means for Solving the Problems

[0006] An inspection apparatus according to an example of the present invention is an inspection apparatus that inspects a plurality of substrates on which wirings provided as the same wiring in design are respectively formed, and includes a measurement unit that measures the capacitance of the wiring of each substrate as a measurement capacitance, an average capacitance calculation unit that calculates an average value of the measurement capacitances measured from the wirings provided as the same wiring in design as an average capacitance, and a capacitance correction unit that calculates a correction capacitance, which is a correction value of the measurement capacitance of a target wiring to be inspected on the target substrate, when one of the plurality of substrates is a target substrate. The capacitance correction unit calculates the correction capacitance by multiplying the ratio of the average capacitance to the measurement capacitance of the wiring of the target substrate by the measurement capacitance of the target wiring.

[0007] Also, an inspection method according to an example of the present invention is an inspection method that inspects a plurality of substrates on which wirings provided as the same wiring in design are respectively formed, and includes a measurement step of measuring the capacitance of the wiring of each substrate as a measurement capacitance, an average capacitance calculation step of calculating an average value of the measurement capacitances measured from the wirings provided as the same wiring in design as an average capacitance, and a capacitance correction step of calculating a correction capacitance, which is a correction value of the measurement capacitance of a target wiring to be inspected on the target substrate, when one of the plurality of substrates is a target substrate. The capacitance correction step calculates the correction capacitance by multiplying the ratio of the average capacitance to the measurement capacitance of the wiring of the target substrate by the measurement capacitance of the target wiring.

Advantages of the Invention

[0008] An inspection apparatus and an inspection method having such a configuration can easily correct variations in capacitance due to manufacturing variations of substrates.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In each figure, components denoted by the same reference numerals represent the same components, and the description thereof will be omitted. The substrate inspection apparatus 1 shown in FIG. 1 is an apparatus for inspecting the wirings of substrates A1 to A25 formed on the panel 100. The substrate inspection apparatus 1 corresponds to an example of an inspection apparatus.

[0011] The substrate inspection apparatus 1 shown in FIG. 1 has a housing 11. Inside the internal space of the housing 11, a substrate fixing device 12, an inspection unit 3, a control unit 2, and an inspection unit moving mechanism 15 for appropriately moving the inspection unit 3 within the housing 11 are mainly provided. The substrate fixing device 12 is configured to fix the panel 100 to be inspected at a predetermined position.

[0012] The inspection unit 3 is located above the panel 100 fixed to the substrate fixing device 12. An inspection jig 4 for inspecting the substrate A formed on the panel 100 is attached to the inspection unit 3. A plurality of probes Pr are attached to the inspection jig 4.

[0013] The panel 100 shown in FIG. 2 includes substrates A1 to A25. Hereinafter, substrates A1 to A25 are collectively referred to as substrate A, and when indicating an individual substrate, the substrate number n is attached to the symbol A and it is referred to as substrate An. The panel 100 is, for example, a panel for PLP (Panel Level Packaging).

[0014] The substrate A may be various substrates such as a package substrate for a semiconductor package, a film carrier, a printed wiring board, a glass epoxy substrate, a flexible substrate, a ceramic multilayer wiring board, an electrode plate for a display such as a liquid crystal display or an EL (Electro-Luminescence) display, a transparent conductive plate for a touch panel, a semiconductor substrate such as a semiconductor wafer, a semiconductor chip, or a CSP (Chip size package). Inspection points such as wiring patterns, pads, lands, solder bumps, vias, and terminals are formed on the substrate A.

[0015] Design-wise, the same wiring pattern is formed on substrates A1 to A25. The number of substrates A included in the panel 100 is not limited to 25. The substrate A is, for example, a substrate before a chip die is mounted on the RDL after the RDL is formed on the carrier when manufacturing a fan-out package, which is a type of semiconductor chip package, in the RDL (Redistribution Layer) first process.

[0016] Referring to FIGS. 3 and 4, the substrate An is, for example, a multilayer substrate including a plurality of wiring layers of a first layer L1, a second layer L2, and a third layer L3. Wiring P(n,1) to P(n,5) with wiring numbers 1 to 5 and reference wirings B(n,1) to B(n,3) with wiring numbers 1 to 3 are formed on the substrate An. Hereinafter, the wiring with wiring number j on the substrate Ai with substrate number i is denoted as wiring P(i,j), and the reference wiring with wiring number j on the substrate Ai with substrate number i is denoted as reference wiring B(i,j).

[0017] Wiring P(n,1) to P(n,5) and reference wiring B(n,1) to B(n,3) correspond to an example of wiring. Hereinafter, wiring P(n,1) to P(n,5) are collectively referred to as wiring Pn, wiring P(1,1) to P(25,5) are collectively referred to as wiring P, reference wiring B(n,1) to B(n,3) are collectively referred to as reference wiring Bn, and reference wiring B(1,1) to B(25,3) are collectively referred to as reference wiring B.

[0018] Wiring P and reference wiring B each include ends e, g and a body f connecting between ends e and g. Ends e, g are, for example, vias, pads, etc. Body f extends in a strip shape and constitutes the main part of each wiring.

[0019] The ends e of wiring P and reference wiring B are formed in the first layer L1. The ends g of wiring P and reference wiring B are formed in the third layer L3. The body f of wiring P(n,1) and reference wiring B(n,1) is formed in the first layer L1. The body f of wiring P(n,2), P(n,3) and reference wiring B(n,2) is formed in the second layer L2. The body f of wiring P(n,4), P(n,5) and reference wiring B(n,3) is formed in the third layer L3.

[0020] In FIG. 3, the part formed in the first layer L1 is shown by a solid line, the part formed in the second layer L2 is shown by a dashed line, and the part formed in the third layer L3 is shown by a one-dot chain line.

[0021] As shown in FIG. 4, on the second layer L2 of the substrate An, a planar pattern G(n,1) formed to face the reference wiring B(n,1) and extend planarly, and a planar pattern G(n,3) formed to face the reference wiring B(n,3) and extend planarly are formed. On the first layer L1 of the substrate An, a planar pattern G(n,2) formed to face the reference wiring B(n,2) and extend planarly is formed.

[0022] The planar patterns G(n,1) and G(n,3) are connected to vias exposed on the first layer L1. By bringing the probe Pr into contact with these vias, the probe Pr can be conductively connected to the planar patterns G(n,1) and G(n,3). In practice, since the first layer L1 connected to the via is always arranged above the via, conductive connection can be achieved by the probe Pr contacting this. The capacitance of the first layer L1 itself can be minimized by forming it small.

[0023] Note that the planar patterns G(n,1), G(n,2), and G(n,3) only need to be arranged opposite to the reference wirings B(n,1), B(n,2), and B(n,3) respectively, and the layers in which they are arranged are not limited to the example shown in FIG. 4.

[0024] The panel 100 is configured by laminating a carrier substrate 102, a release layer 103, and a substrate A in this order. The end e of each wiring is formed on the first layer L1, and the end g of each wiring is formed on the third layer L3. However, after the substrate A is formed on the carrier substrate 102 and before the chip die is mounted on the substrate A, in the panel 100, since the carrier is attached to one surface (the third layer L3) of the substrate A, it is not possible to inspect the conductivity of the wiring by bringing probes into contact with both surfaces of the substrate A.

[0025] Therefore, the substrate inspection apparatus 1 inspects the wiring by measuring the capacitance of the wiring by bringing the probe Pr into contact with the end e, the planar pattern G(n,2), or the via connected to the planar patterns G(n,1) and G(n,3) on the exposed surface (the first layer L1) of the substrate A. In practice, since the first layer L1 connected to the via is always arranged above the via, conductive connection can be achieved by the probe Pr contacting this. The capacitance of the first layer L1 itself can be minimized by forming it small.

[0026] Note that the panel 100 is not limited to the substrate after the substrate A is formed on the carrier and before the chip die is mounted on the substrate A.

[0027] Referring to FIG. 4, the inspection unit 3 includes a plurality of probes Pr, a scanner unit 31, an AC power supply 32, and a plurality of ammeters 33. One end of each probe Pr, one end of the AC power supply 32, one end of each ammeter 33, and the circuit ground are connected to the scanner unit 31. The other end of the AC power supply 32 and the other end of each ammeter 33 are connected to the circuit ground.

[0028] The scanner unit 31 is a switching circuit configured using switching elements such as transistors and relay switches. The scanner unit 31 connects the AC power supply 32 and each ammeter 33 to an arbitrary probe Pr according to a control signal from the control unit 2.

[0029] The AC power supply 32 is an AC power supply circuit that outputs an AC voltage V with a preset frequency f to the probe Pr via the scanner unit 31. The ammeter 33 is an AC ammeter configured using, for example, a shunt resistor, a Hall element, an analog-to-digital converter, etc. The ammeter 33 measures the current I flowing from the probe Pr connected via the scanner unit 31 to the circuit ground, and transmits a signal indicating the current I to the control unit 2. The voltage V and the current I may be effective values or peak values.

[0030] Referring to FIG. 1, the control unit 2 is configured using, for example, a microcomputer including a CPU (Central Processing Unit) that executes a predetermined logical operation, a RAM (Random Access Memory) that temporarily stores data, a non-volatile storage device that stores a predetermined control program in advance, and peripheral circuits thereof.

[0031] The control unit 2 functions as an inspection control unit 21, a measurement unit 22, an average capacitance calculation unit 23, a capacitance correction unit 24, a reference value calculation unit 25, and a determination unit 26, for example, by executing the above-described control program.

[0032] The inspection control unit 21 appropriately moves the inspection unit 3 and brings each probe Pr into contact with each inspection point such as the end e on the substrate A fixed to the substrate fixing device 12.

[0033] The measuring unit 22 measures the capacitance of the wiring of each substrate A as the measurement capacitance. Specifically, the measuring unit 22 measures the capacitance between the reference wiring B(n,1) and the planar pattern G(n,1) as the measurement capacitance of the reference wiring B(n,1), measures the capacitance between the reference wiring B(n,2) and the planar pattern G(n,2) as the measurement capacitance of the reference wiring B(n,2), and measures the capacitance between the reference wiring B(n,3) and the planar pattern G(n,3) as the measurement capacitance of the reference wiring B(n,3).

[0034] Strictly speaking, the capacitance measured by bringing the probe Pr into contact with the reference wiring B(n,1) and the planar pattern G(n,1) also includes the capacitance generated between the reference wiring B(n,1) and the surrounding materials. Similarly, the capacitance measured by bringing the probe Pr into contact with the reference wiring B(n,2) and the planar pattern G(n,2) also includes the capacitance generated between the reference wiring B(n,2) and the surrounding materials, and the capacitance measured by bringing the probe Pr into contact with the reference wiring B(n,3) and the planar pattern G(n,3) also includes the capacitance generated between the reference wiring B(n,3) and the surrounding materials.

[0035] However, the capacitance is inversely proportional to the distance and proportional to the area. Therefore, if the distances between the reference wirings B(n,1), B(n,2), B(n,3) and the surrounding wirings are far apart, the capacitances between the reference wiring B(n,1) with a large area and the planar pattern G(n,1), between the reference wiring B(n,2) and the planar pattern G(n,2), and between the reference wiring B(n,3) and the planar pattern G(n,3) become dominant.

[0036] Therefore, the capacitance measured by bringing a pair of probes Pr into contact with the reference wiring B(n,1) and the planar pattern G(n,1) can be approximated as the capacitance of the reference wiring B(n,1), the capacitance measured by bringing a pair of probes Pr into contact with the reference wiring B(n,2) and the planar pattern G(n,2) can be approximated as the capacitance of the reference wiring B(n,2), and the capacitance measured by bringing a pair of probes Pr into contact with the reference wiring B(n,3) and the planar pattern G(n,3) can be approximated as the capacitance of the reference wiring B(n,3).

[0037] Also, the capacitance of the wiring Pn may be the capacitance between the wiring Pn and all other wirings and patterns, or the capacitance between the wiring Pn and one or more other preset wirings or patterns. Alternatively, when the carrier substrate 102 is a conductive substrate, the capacitance of the wiring Pn may be the capacitance between the wiring Pn and the carrier substrate 102. The measurement unit 22 may use the capacitance measured between a pair of probes Pr that contact the wiring Pn and an arbitrarily set wiring or pattern as the measured capacitance of the wiring Pn.

[0038] The measurement unit 22 connects the ammeter 33 to the probe Pr that contacts the reference wiring Bn or the wiring Pn to be measured by the scanner unit 31. Also, the measurement unit 22 connects the AC power supply 32 to the probe Pr paired with the probe Pr by the scanner unit 31.

[0039] Then, a current I flows through the capacitance of the reference wiring Bn or the wiring Pn to be measured due to the voltage V of frequency f output from the AC power supply 32, and the current I is measured by the ammeter 33.

[0040] When a current I flows when a voltage V of frequency f is applied to the capacitance X, the capacitance X is given by the following formula (1). Capacitance X = I / (V × 2πf) ···(1)

[0041] In this case, since V and 2πf are known, if the current I is obtained, the capacitance X can be determined. Therefore, the measurement unit 22 can measure the capacitance X as the measured capacitance C.

[0042] Hereinafter, the fact that the measurement unit 22 measures the capacitance X using the scanner unit 31, the AC power supply 32, and the ammeter 33 will be simply described as the measurement unit 22 measures the capacitance X, that is, the measured capacitance C.

[0043] The average capacitance calculation unit 23 calculates the average value of the measured capacitances C measured from the wirings corresponding to each other as the average capacitance Cav. The wirings corresponding to each other are the wirings formed as the same wiring in design for each substrate A. For example, the wirings with the same wiring number, the reference wirings B(1,1), B(2,1), B(3,1), ··· are wirings corresponding to each other, the reference wirings B(1,2), B(2,2), B(3,2), ··· are wirings corresponding to each other, and the reference wirings B(1,3), B(2,3), B(3,3), ··· are wirings corresponding to each other.

[0044] When the capacitance correction unit 24 uses the substrate Ai with the substrate number i among the plurality of substrates A1 to A25 as the target substrate, the capacitance correction unit 24 multiplies the ratio of the average capacitance Cav to the measured capacitance Ci of the wiring of the target substrate Ai by the measured capacitance C of the target wiring to be inspected on the target substrate Ai, thereby calculating the corrected capacitance Cc which is the correction value of the measured capacitance C of the target wiring.

[0045] Furthermore, the capacitance correction unit 24 calculates the corrected capacitance Cc for the target wiring of each substrate A by sequentially using each substrate A as the target substrate.

[0046] The reference value calculation unit 25 calculates the average value of the corrected capacitances Cc for the target wiring of each substrate A as the determination reference value Cref.

[0047] The determination unit 26 determines the corrected capacitance Cc based on the determination reference value Cref.

[0048] Next, an example of the operation of the substrate inspection apparatus 1 that executes the inspection method according to an example of the present invention will be described with reference to FIGS. 5 to 8. In the following description, the measured capacitance of the reference wiring B(i,j) is denoted as C(B(i,j)), the measured capacitance of the wiring P(i,j) is denoted as C(P(i,j)), and the corrected capacitance of the wiring P(i,j) is denoted as Cc(P(i,j)).

[0049] First, the measurement unit 22 initializes the substrate number i to 1 (step S1).

[0050] Next, the inspection control unit 21 brings each probe Pr into contact with the first layer L1 of the substrate Ai. Specifically, each probe Pr is brought into contact with the reference wirings B(i,1) to B(i,3), the wirings P(i,1) to P(i,5), the planar patterns G(i,1) to G(i,3), and any wiring paired with the wirings P(i,1) to P(i,5) (step S2).

[0051] Next, the measurement unit 22 measures the measured capacitances C(B(i,1)), C(B(i,2)), C(B(i,3)), and the measured capacitances C(P(i,1)), C(P(i,2)), C(P(i,3)), C(P(i,4)), C(P(i,5)) (step S2: measurement step).

[0052] Next, the measurement unit 22 compares the substrate number i with 25 (step S3). If the substrate number i is not 25 (NO in step S3), 1 is added to the substrate number i to measure a new substrate A (step S4), and steps S2 and S3 are repeated again. On the other hand, if the substrate number i is 25 (YES in step S3), since the measured capacitance C has been measured for all wirings, the process proceeds to step S5.

[0053] Next, the average capacitance calculation unit 23 sets the average value of the measured capacitances C(B(1,1)) to C(B(25,1)) as the average capacitance Cav(L1) of the first layer L1, the average value of the measured capacitances C(B(1,2)) to C(B(25,2)) as the average capacitance Cav(L2) of the second layer L2, and the average value of the measured capacitances C(B(1,3)) to C(B(25,3)) as the average capacitance Cav(L3) of the third layer L3 (step S5: average capacitance calculation step).

[0054] The measured capacitances C(B(1,1)) to C(B(25,1)) are the measured capacitances C measured from the reference wiring B corresponding to each other with wiring number 1, which is the reference wiring B formed in the first layer L1. The measured capacitances C(B(1,2)) to C(B(25,2)) are the measured capacitances C measured from the reference wiring B corresponding to each other with wiring number 2, which is the reference wiring B formed in the second layer L2. The measured capacitances C(B(1,3)) to C(B(25,3)) are the measured capacitances C measured from the reference wiring B corresponding to each other with wiring number 3, which is the reference wiring B formed in the third layer L3.

[0055] Note that, in one substrate A, an example in which one reference wiring B is provided for each layer has been shown, but a plurality of reference wirings B may be provided for each layer. Then, the measured capacitances C of the plurality of reference wirings B for each substrate may be averaged for each layer for a plurality of substrates to calculate average capacitances Cav(L1), Cav(L2), and Cav(L3).

[0056] Next, the capacitance correction unit 24 initializes the substrate number i to 1 (step S6).

[0057] Next, the capacitance correction unit 24 calculates the correction capacitance Cc(P(i,1)) of the wiring P(i,1) in the first layer L1 based on the following formula (1) (step S7: capacitance correction step). Correction capacitance Cc(P(i,1)) = C(P(i,1)) × Cav(L1) / C(B(i,1)) ···(1)

[0058] In step S7, the substrate Ai corresponds to the target substrate, the wiring P(i,1) corresponds to the target wiring in the first layer L1, the reference wiring B(i,1) corresponds to the wiring of the target substrate Ai, and Cav(L1) / C(B(i,1)) corresponds to the ratio of the average capacitance Cav(L1) to the measured capacitance C(B(i,1)) of the wiring of the target substrate Ai.

[0059] Next, the capacitance correction unit 24 calculates the correction capacitances Cc(P(i,2)) and Cc(P(i,3)) of the wirings P(i,2) and P(i,3) in the second layer L2 based on the following formulas (2) and (3) (step S8: capacitance correction step). Correction capacitance Cc(P(i, 2)) = C(P(i, 2)) × Cav(L2) / C(B(i, 2)) ···(2) Correction capacitance Cc(P(i, 3)) = C(P(i, 3)) × Cav(L2) / C(B(i, 2)) ···(3)

[0060] In step S8, the substrate Ai corresponds to the target substrate, the wirings P(i, 2) and P(i, 3) correspond to the target wirings of the second layer L2, the reference wiring B(i, 2) corresponds to the wiring of the target substrate Ai, and Cav(L2) / C(B(i, 2)) corresponds to the ratio of the average capacitance Cav(L2) to the measured capacitance C(B(i, 2)) of the wiring of the target substrate Ai.

[0061] Next, the capacitance correction unit 24 calculates the correction capacitances Cc(P(i, 4)) and Cc(P(i, 5)) of the wirings P(i, 4) and P(i, 5) of the third layer L3 based on the following formulas (4) and (5) (step S9: capacitance correction process). Correction capacitance Cc(P(i, 4)) = C(P(i, 4)) × Cav(L3) / C(B(i, 3)) ···(4) Correction capacitance Cc(P(i, 5)) = C(P(i, 5)) × Cav(L3) / C(B(i, 3)) ···(5)

[0062] In step S9, the substrate Ai corresponds to the target substrate, the wirings P(i, 4) and P(i, 5) correspond to the target wirings of the third layer L3, the reference wiring B(i, 3) corresponds to the wiring of the target substrate Ai, and Cav(L3) / C(B(i, 3)) corresponds to the ratio of the average capacitance Cav(L3) to the measured capacitance C(B(i, 3)) of the wiring of the target substrate Ai.

[0063] Next, the capacitance correction unit 24 compares the substrate number i with 25 (step S10). If the substrate number i is not 25 (NO in step S10), 1 is added to the substrate number i to correct a new substrate A (step S11), and steps S7 to 10 are repeated again. On the other hand, if the substrate number i is 25 (YES in step S10), it means that all the measured capacitances C have been corrected, so the process proceeds to step S21.

[0064] As shown in FIG. 9, even for wirings P with the same wiring number, the measured capacitance C varies from substrate A to substrate A. The measured capacitance C decreases when the wiring P is open-circuited, and increases when the wiring P is short-circuited to another wiring or the like. If there is no variation in the substrate, disconnection or short-circuit of the wiring P can be determined based on the increase or decrease in the measured capacitance C.

[0065] However, as shown in FIG. 9, if the variation in the measured capacitance C due to substrate variation is large, it is not easy to determine disconnection or short-circuit of the wiring P based on the measured capacitance C.

[0066] For example, for the measured capacitance C(P(2,2)) shown in FIG. 9, the measured capacitance C(P(2,2)) when the wiring P(2,2) is open-circuited is shown by a solid line, and the measured capacitance C(P(2,2)) when the wiring P(2,2) is normal is shown by a dashed line. In the example shown in FIG. 9, the measured capacitance C(P(2,2)) when the wiring P(2,2) is open-circuited is smaller than the measured capacitance C(P(1,2)) of the normal wiring P(1,2) and larger than the measured capacitance C(P(25,2)) of the normal wiring P(25,2). Therefore, it is difficult to determine that the wiring P(2,2) is defective based on the measured capacitance C(P(2,2)).

[0067] As shown in FIG. 10, for the corrected capacitances Cc(P(1,1)) to Cc(P(25,5)) corrected in steps S7 to S9, if the wiring P is normal, the influence due to substrate variation is reduced for wirings P with the same wiring number and corresponding to each other, and they have substantially the same capacitance. Thus, according to steps S1 to S11, it becomes easy to correct the variation in the capacitance X due to manufacturing variation of the substrate A.

[0068] Also, in the manufacturing process of the substrate A, since the wiring P and the reference wiring B are formed for each layer, even within the same substrate A, the variation may be different for each layer. Therefore, in step S2, the measurement capacitances C(B(1,1)) to C(B(25,3)) are measured from the reference wirings B(n,1) to B(n,3) provided for each layer. In step S5, the average capacitances Cav(L1), Cav(L2), and Cav(L3) are calculated for each layer. In steps S7 to S9, the measurement capacitances C(P(1,1)) to C(P(25,5)) are corrected for each layer to calculate the corrected capacitances Cc(P(1,1)) to Cc(P(25,5)).

[0069] Thereby, the corrected capacitances Cc(P(1,1)) to Cc(P(25,5)) can be calculated so as to reduce the difference in variation for each layer.

[0070] Next, in step S21, the reference value calculation unit 25 sets the average value of the corrected capacitances Cc(P(1,1)) to C(P(25,1)) as the determination reference value Cref(1) for the wiring P(n,1), the average value of the corrected capacitances Cc(P(1,2)) to Cc(P(25,2)) as the determination reference value Cref(2) for the wiring P(n,2), the average value of the corrected capacitances Cc(P(1,3)) to Cc(P(25,3)) as the determination reference value Cref(3) for the wiring P(n,3), the average value of the corrected capacitances Cc(P(1,4)) to Cc(P(25,4)) as the determination reference value Cref(4) for the wiring P(n,4), and the average value of the corrected capacitances Cc(P(1,5)) to Cc(P(25,5)) as the determination reference value Cref(5) for the wiring P(n,5) (step S21: reference value calculation step).

[0071] Next, the determination unit 26 initializes the substrate number i and the wiring number j to 1 (step S22).

[0072] Next, if the absolute value of {Cc(P(i,j)) - Cref(j)} / Cref(j) is equal to or less than the determination ratio Ref (YES in step S23), the determination unit 26 determines that the wiring P(i,j) is good (step S24), and if it exceeds the determination ratio Ref (NO in step S23), the determination unit 26 determines that the wiring P(i,j) is bad (step S25).

[0073] That is, when the ratio of the difference between the correction capacitance Cc of each wiring P and the determination reference value Cref with respect to the determination reference value Cref exceeds a preset determination ratio Ref, the determination unit 26 can determine that the wiring P is defective. The determination ratio Ref may be set as appropriate according to the required inspection accuracy.

[0074] Next, the determination unit 26 compares the wiring number j with 5 (step S26). If the wiring number j is not 5 (NO in step S26), 1 is added to the wiring number j to determine the other wiring P on the substrate Ai (step S27), and steps S23 to S26 are repeated again.

[0075] On the other hand, if the wiring number j is 5 (YES in step S26), the substrate number i is compared with 25 (step S28). If the substrate number i is not 25 (NO in step S28), 1 is added to the substrate number i to determine a new substrate A, the wiring number j is initialized to 1 (step S29), and steps S23 to 28 are repeated again.

[0076] On the other hand, if the substrate number i is 25 (YES in step S28), it means that the pass / fail of all the wirings P has been determined, so the process proceeds to step S30.

[0077] In step S30, the determination unit 26 checks whether there is a wiring P determined to be defective in step S25 (step S30). If there is no wiring P determined to be defective (NO in step S30), the process ends.

[0078] On the other hand, if there is at least one wiring P determined to be defective (YES in step S30), the process proceeds to step S41.

[0079] When there is at least one wiring P determined to be defective (YES in step S30), the average value calculated in step S21 including the correction capacitance Cc of the defective wiring P is used as the determination reference value Cref. Therefore, the pass / fail determination accuracy of the wiring P based on the determination reference value Cref decreases.

[0080] Therefore, in step S41, the reference value calculation unit 25 sets the average value of the remaining correction capacitances obtained by excluding the correction capacitances of the wirings determined to be defective from the correction capacitances Cc(P(1,1)) to C(P(25,1)) as the new determination reference value Cref(1) for the wiring P(n,1).

[0081] Similarly, the reference value calculation unit 25 sets the average value of the remaining correction capacitances obtained by excluding the correction capacitances of the wirings determined to be defective from the correction capacitances Cc(P(1,2)) to C(P(25,2)) as the new determination reference value Cref(2) for the wiring P(n,2) (step S41).

[0082] The reference value calculation unit 25 sets the average value of the remaining correction capacitances obtained by excluding the correction capacitances of the wirings determined to be defective from the correction capacitances Cc(P(1,3)) to C(P(25,3)) as the new determination reference value Cref(3) for the wiring P(n,3) (step S41).

[0083] The reference value calculation unit 25 sets the average value of the remaining correction capacitances obtained by excluding the correction capacitances of the wirings determined to be defective from the correction capacitances Cc(P(1,4)) to C(P(25,4)) as the new determination reference value Cref(4) for the wiring P(n,4) (step S41).

[0084] The reference value calculation unit 25 sets the average value of the remaining correction capacitances obtained by excluding the correction capacitances of the wirings determined to be defective from the correction capacitances Cc(P(1,5)) to C(P(25,5)) as the new determination reference value Cref(5) for the wiring P(n,5) (step S41).

[0085] According to step S41, when there is a defective wiring, a new determination reference value Cref can be obtained based on the remaining correction capacitances excluding the correction capacitance of the defective wiring, so the accuracy of the determination reference value Cref can be improved.

[0086] Next, the determination unit 26 initializes the board number i and the wiring number j to 1 (step S42).

[0087] Next, the determination unit 26 checks whether the wiring P(i,j) was defective in step S25 (step S43). If the wiring P(i,j) is not defective (NO in step S43), the determination unit 26 proceeds to step S51. If the wiring P(i,j) is defective (YES in step S43), the determination unit 26 proceeds to step S54.

[0088] In step S51, based on a new determination reference value Cref, if the absolute value of {Cc(P(i,j)) - Cref(j)} / Cref(j) is less than or equal to the determination ratio Ref (YES in step S51), the determination unit 26 determines that the wiring P(i,j) is good (step S52). If it exceeds the determination ratio Ref (NO in step S51), the determination unit 26 determines that the wiring P(i,j) is defective (step S53).

[0089] Next, the determination unit 26 compares the wiring number j with 5 (step S54). If the wiring number j is not 5 (NO in step S54), it adds 1 to the wiring number j to determine other wirings P on the substrate Ai (step S55), and repeats steps S51 - S54 again.

[0090] On the other hand, if the wiring number j is 5 (YES in step S54), it compares the substrate number i with 25 (step S56). If the substrate number i is not 25 (NO in step S56), it adds 1 to the substrate number i and initializes the wiring number j to 1 to determine a new substrate A (step S57), and repeats steps S51 - S56 again.

[0091] On the other hand, if the substrate number i is 25 (YES in step S56), since it has finished determining the pass / fail of all wirings P that were not defective last time based on the new determination reference value Cref, it proceeds to step S58.

[0092] In step S58, the determination unit 26 checks whether there is any wiring P newly determined to be defective in step S53 (step S58). If there is no wiring P newly determined to be defective (NO in step S58), the process ends.

[0093] On the other hand, if there is even one wiring P newly determined to be defective (YES in step S58), steps S41 to S58 are repeated again.

[0094] As described above, according to the processes of steps S30, S41 to S58, when there is a wiring P determined to be defective, the influence of the wiring P determined to be defective is eliminated, a new determination reference value Cref is calculated, and based on the newly calculated determination reference value Cref, the pass / fail determination of the wiring P that has been determined to be good is re - judged. Therefore, the pass / fail determination accuracy of the wiring P is improved.

[0095] Note that it is not always necessary to execute steps S30 to S53. If YES in step S28, the process may be terminated.

[0096] Also, the reference wiring B is not limited to the example of being provided for each layer of the substrate A. For example, only the reference wiring B(n, 2) is provided as the reference wiring, and in steps S7 and S9, Cav(L2) / C(B(i, 2)) may be used instead of Cav(L1) / C(B(i, 1)) and Cav(L3) / C(B(i, 3)).

[0097] Also, it is not limited to the example of providing the reference wiring B separately from the wiring P to be inspected. It is also possible not to provide the reference wiring B and use any of the wirings P instead of the reference wiring B. For example, wiring P(n, 2) and P(n, 4) may be used instead of the reference wirings B(n, 2) and B(n, 3).

[0098] In this case, in step S5, the average value of the measured capacitances C(P(1, 2)) to C(P(25, 2)) can be set as the average capacitance Cav(L2) of the second layer L2, and the average value of the measured capacitances C(P(1, 4)) to C(P(25, 4)) can be set as the average capacitance Cav(L3) of the third layer L3. Also, in step S8, the measured capacitance C(P(i, 2)) can be used instead of the measured capacitance C(B(i, 2)), and in step S9, the measured capacitance C(P(i, 4)) can be used instead of the measured capacitance C(B(i, 3)).

[0099] As a result, in steps S23 to S25 and steps S51 to S53, although the wirings P(n,2) and P(n,4) cannot be inspected, the wirings P(n,3) and P(n,5) can be inspected. When inspecting the wirings P(n,2) and P(n,4), the wirings P(n,3) and P(n,5) may be used instead of the reference wirings B(n,2) and B(n,3).

[0100] In this way, it is not necessary to provide the reference wiring B separately from the wiring P. On the other hand, the wiring P routed to form the circuit is routed in a complex manner and is likely to have a complex shape, and the capacitance X is likely to become unstable. However, when configured to include the reference wiring B separately from the wiring P, it is easy to form the reference wiring B for calculating the average capacitance in a shape and arrangement in which the capacitance is likely to be stable, regardless of the necessity on the circuit.

[0101] Further, the substrate inspection apparatus and inspection method according to the present invention only need to be able to easily correct at least the variation in capacitance due to manufacturing variations of the substrate. If YES in step S10, the process may end without executing steps S21 to S58.

[0102] Also, in step S43, an example was shown in which the wiring P once determined to be defective is not determined again in steps S51 to S53, but it is also possible to shift from step S42 to step S51 without executing step S43.

[0103] That is, an inspection apparatus according to an example of the present invention is an inspection apparatus that inspects a plurality of substrates on which wirings provided as the same wiring in design are respectively formed, and includes a measurement unit that measures the capacitance of the wiring of each substrate as a measurement capacitance, an average capacitance calculation unit that calculates an average value of the measurement capacitances measured from the wirings provided as the same wiring in design as an average capacitance, and a capacitance correction unit that calculates a correction capacitance, which is a correction value of the measurement capacitance of a target wiring to be inspected on the target substrate, when one of the plurality of substrates is a target substrate. The capacitance correction unit calculates the correction capacitance by multiplying the ratio of the average capacitance to the measurement capacitance of the wiring of the target substrate by the measurement capacitance of the target wiring.

[0104] Further, an inspection method according to an example of the present invention is an inspection method that inspects a plurality of substrates on which wirings provided as the same wiring in design are respectively formed, and includes a measurement step of measuring the capacitance of the wiring of each substrate as a measurement capacitance, an average capacitance calculation step of calculating an average value of the measurement capacitances measured from the wirings provided as the same wiring in design as an average capacitance, and a capacitance correction step of calculating a correction capacitance, which is a correction value of the measurement capacitance of a target wiring to be inspected on the target substrate, when one of the plurality of substrates is a target substrate. The capacitance correction step calculates the correction capacitance by multiplying the ratio of the average capacitance to the measurement capacitance of the wiring of the target substrate by the measurement capacitance of the target wiring.

[0105] According to these configurations, the capacitance of the wiring of each substrate is measured as a measurement capacitance, and the average value of the measurement capacitances measured from the corresponding wirings provided as the same wiring in design is calculated as an average capacitance. Then, the ratio of the average capacitance to the measurement capacitance of the wiring of a target substrate, which is one of the plurality of substrates, is multiplied by the measurement capacitance of the target wiring to be inspected on the target substrate to calculate the correction capacitance of the target wiring. As a result, the variation between substrates in the correction capacitance is reduced, so that it becomes easy to correct the variation in capacitance due to manufacturing variations of the substrates.

[0106] Further, the capacitance correction unit calculates the correction capacitance of the target wiring of each of the plurality of substrates with each of the substrates being the target substrate, and the inspection apparatus preferably further includes a reference value calculation unit that calculates the average value of the respective correction capacitances as a determination reference value, and a determination unit that determines each of the correction capacitances based on the determination reference value.

[0107] According to this configuration, since the determination reference value can be automatically calculated based on the correction capacitance of the target wiring of each target substrate, it becomes easy to determine each correction capacitance.

[0108] Further, the reference value calculation unit calculates the average value of the remaining correction capacitances excluding the correction capacitances determined to be defective by the determination unit as a new determination reference value, and the determination unit preferably determines at least the remaining correction capacitances based on the new determination reference value.

[0109] According to this configuration, since the correction capacitance of the defective wiring is excluded from the data used as the basis for the determination reference value and a new determination reference value is calculated, the determination accuracy based on the new determination reference value is improved.

[0110] Further, the wiring includes a reference wiring that is not an inspection target and is provided as wiring that is the same in design among the plurality of substrates. The measurement unit measures the capacitance of the reference wiring as the measured capacitance of the reference wiring, and the average capacitance calculation unit preferably calculates the average value of the measured capacitances of the reference wiring on each substrate as the average capacitance.

[0111] According to this configuration, the average capacitance is calculated based on the measured capacitance measured from a reference wiring different from the wiring to be inspected. The wiring to be inspected routed for constructing a circuit is routed in a complex manner and tends to have a complex shape, and its capacitance tends to be unstable. However, when a configuration is provided with a reference wiring separate from the wiring to be inspected, it is easy to make the reference wiring for calculating the average capacitance have a shape and arrangement in which the capacitance is likely to be stable, regardless of the necessity on the circuit.

[0112] Further, the substrate is a multilayer substrate, and it is preferable that the reference wiring is provided for each layer of the substrate.

[0113] In the manufacturing process of the substrate, since the wiring and the reference wiring are formed for each layer, even within the same substrate, the variation may be different for each layer. Therefore, by providing the reference wiring for each layer of the substrate, it becomes easy to calculate the correction capacitance so as to reduce the difference in variation for each layer.

[0114] Further, it is preferable to include a probe for contacting the wiring, and the measuring unit measures the capacitance via the probe.

[0115] According to this configuration, the capacitance of the wiring can be measured by bringing the probe into contact with the wiring.

Explanation of Reference Signs

[0116] 1 Substrate inspection device, 2 Control unit, 3 Inspection unit, 4 Inspection jig, 11 Housing, 12 Substrate fixing device, 15 Inspection unit moving mechanism, 21 Inspection control unit, 22 Measuring unit, 23 Average capacitance calculation unit, 24 Capacitance correction unit, 25 Reference value calculation unit, 26 Determination unit, 31 Scanner unit, 32 AC power supply, 33 Ammeter, 100 Panel, 102 Carrier substrate, 103 Release layer, A, A1 - A25 Substrate, B Reference wiring, C Measured capacitance, Cav Average capacitance, Cc Correction capacitance, Cref Judgment reference value, G Planar pattern, I Current, L1 First layer, L2 Second layer, L3 Third layer, P Wiring, Pr Probe, Ref Judgment ratio, V Voltage, e, g End portion, f Body, X Capacitance

Claims

1. An inspection apparatus for inspecting a plurality of substrates each formed with wirings provided as wirings identical in design, comprising: a measurement unit that measures the capacitance of the wirings of each of the substrates as a measurement capacitance; an average capacitance calculation unit that calculates an average value of the measurement capacitances measured from the wirings provided as wirings identical in design as an average capacitance; a capacitance correction unit that calculates a correction capacitance, which is a correction value of the measurement capacitance of a target wiring to be inspected on a target substrate, when one of the plurality of substrates is taken as the target substrate; The inspection apparatus, wherein the capacitance correction unit calculates the correction capacitance by multiplying the ratio of the average capacitance to the measurement capacitance of the wiring of the target substrate by the measurement capacitance of the target wiring.

2. The capacitance correction unit calculates the correction capacitance of the target wiring of each of the target substrates with each of the plurality of substrates being taken as the target substrate, The inspection apparatus further comprises a reference value calculation unit that calculates an average value of the respective correction capacitances as a determination reference value, The inspection apparatus according to claim 1, further comprising a determination unit that determines each of the correction capacitances based on the determination reference value.

3. The reference value calculation unit calculates an average value of the remaining correction capacitances excluding the correction capacitances determined to be defective by the determination unit as a new determination reference value, The inspection apparatus according to claim 2, wherein the determination unit determines at least the remaining correction capacitances based on the new determination reference value.

4. The wiring includes a reference wiring that is not an inspection target and is provided as a wiring identical in design among the plurality of substrates, The measurement unit measures the capacitance of the reference wiring as the measurement capacitance of the reference wiring, The inspection apparatus according to any one of claims 1 to 3, wherein the average capacitance calculation unit calculates an average value of the measurement capacitances of the reference wiring on each of the substrates as the average capacitance.

5. The substrate is a multilayer substrate, The inspection apparatus according to claim 4, wherein the reference wiring is provided for each layer of the substrate.

6. Comprising a probe for contacting the wiring, The inspection apparatus according to any one of claims 1 to 5, wherein the measurement unit measures the capacitance via the probe.

7. An inspection method for inspecting a plurality of substrates each formed with wirings provided as wirings identical in design, comprising: a measurement step of measuring the capacitance of the wirings of each of the substrates as a measurement capacitance; An average capacitance calculation step of calculating, as an average capacitance, an average value of measured capacitances measured from wirings provided as the same wiring in terms of design; A capacitance correction step of calculating a correction capacitance, which is a correction value of the measured capacitance of a target wiring to be inspected on the target substrate, when one of the plurality of substrates is set as the target substrate; and The capacitance correction step calculates the correction capacitance by multiplying a ratio of the average capacitance to the measured capacitance of the wiring of the target substrate by the measured capacitance of the target wiring.

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