JP2006278762A - Inspection method and inspection apparatus for multilayered substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection method and an inspection apparatus for a multilayered substrate, whereby the defect of the multilayered substrate that might otherwise be discriminated to be a non-defective product can be found out, using a simple method. <P>SOLUTION: Resistance measurement for detecting a partial defect and a joining abnormity or the like of connection holes 8 formed to each layer and an inter-layer insulation layer 6 is carried out twice, with a measurement current of several mA and a measurement current from several tens of times to several hundreds of times of the several mA. Since the resistance change of the local resistance abnormality location due to heat generation is greater than that of normal positions, the resistance abnormality location 20 can easily be detected, by checking a difference of measured values conducted twice by changing the measurement current. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multilayer substrate inspection method and an inspection method for detecting defects such as partial defects or bonding abnormalities in pattern layers of a multilayer substrate, or partial defects or bonding abnormalities in connection holes formed in an interlayer insulating film.

  In order to inspect the manufactured multilayer substrate, the terminals of the inspection and measurement device are brought into contact with a pair of pad portions formed on the multilayer substrate, the resistance between the pair of pad portions is measured, and the continuity between the pad portions is measured. There are cases where the path is inspected for defects. Since a large number of pad portions are formed on a single multilayer substrate, such resistance measurement is repeated between a pair of different pad portions in the inspection.

  In the conventional inspection method, a good product and a defective product are distinguished depending on whether or not the measured resistance value satisfies a reference value. However, the resistance between the pair of pad portions to be inspected in the multilayer substrate is a very small value of, for example, about 3 mΩ, and depending on the type of defect, it is difficult to discriminate and there is a possibility that a defective product is judged as a good product. . That is, in order to measure a minute resistance by passing a weak measurement current of about several mA and measuring the voltage between them, even if it satisfies a predetermined reference value, a defect is hidden inside. There was a possibility.

  For example, even if a reference value for resistance is set, there is variation among lots in the manufacturing process, and if a good product and a defective product are judged with the same reference value, the defective product There was a possibility of mixing.

In addition, as described in the following Patent Document 1, by passing two types of measurement currents, the influence of the contact resistance between the measurement terminal and the pad portion is eliminated, and the minute resistance is accurately measured. A method for detecting a conduction failure or the like is known. However, in this method, it is possible to detect an accurate resistance, but when determining whether or not it is a non-defective product, it is determined whether or not the resistance satisfies a predetermined reference value, as in the past. In order to detect a continuity failure or the like, there was still a possibility that a defect was hidden in what was judged as a good product. That is, even if the resistance is obtained accurately, the conventional method of uniformly determining and selecting the reference value may cause defects to be hidden in what is determined to be a non-defective product.
JP 2004-279270 A

  The present invention has been made in view of such a situation, and an electronic component inspection method (in particular, a multilayer substrate inspection method) capable of finding a defect that may be judged as a non-defective product by a simple method, and An object is to provide an inspection device.

In order to achieve the above object, the method of inspecting an electronic component according to the present invention (in particular, inspection of a multilayer substrate, the same applies hereinafter)
A method for inspecting an electronic component having at least a first pad part and a second pad part connected to the first pad part through a conduction path,
A first current is passed between the first pad portion and the second pad portion, a first voltage generated between these pad portions is measured, and these pads are based on the first current and the first voltage. Calculating a first resistance (R1) between the sections;
A second current that is 20 times greater than the first current is passed between the first pad portion and the second pad portion, a second voltage generated between these pad portions is measured, and the second current is measured. Calculating a second resistance (R2) between these pad portions based on the current and the second voltage;
And detecting a defect based on the relationship between the second resistor (R2) and the first resistor (R1).

In addition, an electronic component inspection apparatus according to the present invention includes:
An inspection apparatus for inspecting an electronic component having at least a first pad part and a second pad part connected to the first pad part through a conduction path,
A first current is passed between the first pad portion and the second pad portion, a first voltage generated between these pad portions is measured, and these pads are based on the first current and the first voltage. First resistance calculating means for calculating a first resistance (R1) between the sections;
A second current that is 20 times greater than the first current is passed between the first pad portion and the second pad portion, a second voltage generated between these pad portions is measured, and the second current is measured. Second resistance calculating means for calculating a second resistance (R2) between these pad portions based on the current and the second voltage;
Defect detecting means for detecting a defect based on the relationship between the second resistor (R2) and the first resistor (R1).

  In the electronic component inspection method and inspection apparatus according to the present invention, the resistance value between the pair of pad portions to be inspected is not determined, and it is not determined whether the value is different from the reference value. In the present invention, between the first pad portion and the second pad portion, the first current is 20 times or more, preferably 50 times or more, more preferably 100 times or more, particularly preferably 500 times or more larger than the first current. Pass two currents. As a result, when there is a partially defective portion between the first pad portion and the second pad portion, the resistance is partially high, so that heat generation at the defective portion is larger than that at the normal location. . The temperature coefficient of resistance is substantially determined by the resistance material, and in the case of a single metal, the lattice vibration increases as the temperature rises and electrons are scattered, so that the resistance increases.

  Therefore, a component having a defect between the pad portions has a higher resistance than a normal product due to local heat generation when a large current (second current) is passed. Therefore, if a change in resistance at a small current (first current) and a change in resistance at a large current are observed, a change in resistance is greater in a defective one than in a normal product. This makes it possible to detect the presence or absence of defects. That is, when heat is generated at the defective portion when the second current is applied, the measured second resistance is different from the first resistance in a state where no heat is generated (when the first current is applied).

  In the method of the present invention, it is determined whether or not the change (difference or ratio) of the resistance is equal to or greater than a predetermined value. If the change is equal to or greater than the predetermined value, it is determined that a defect exists. When the change in resistance (difference or ratio) is equal to or greater than a predetermined value, it is predicted that heat is generated at the defective portion. Conversely, if the resistance change (difference or ratio) is less than or equal to a predetermined value, it can be determined that there is no heat generation and no defective portion. For this reason, the method of the present invention can very easily detect defects that could not be detected conventionally.

  In the present invention, when there is a defective portion, the heat generation is caused at the defective portion at the second current even when the energizing time of the second current is made longer than the energizing time of the first current. be able to.

  In the present invention, it may be determined that a defect exists when a difference (R2−R1) between the second resistance and the first resistance is equal to or greater than a predetermined value. Alternatively, it may be determined that a defect exists when a ratio ((R2−R1) / R1) between the second resistor and the first resistor with respect to the first resistor is equal to or greater than a predetermined value.

  In the present invention, when there is a defective portion between the first pad portion and the second pad portion, the first current is a current value that does not cause the defective portion to generate heat, and the second current Is a current value at which the defective portion generates heat.

  Preferably, the first current is a constant current in a range of 1 to 10 mA, and the second current is a constant current of 500 mA or more.

  Preferably, a terminal for applying the first current and the second current is different from a terminal for measuring the first voltage and the second voltage, and the measuring device has a total of four terminals. That is, the 4-terminal method is preferable. The 4-terminal method can measure the resistance with higher accuracy than the 2-terminal method.

  The inspection method and inspection apparatus according to the present invention are particularly suitable for detecting defects in a multilayer substrate such as a low-melting glass multilayer substrate, but are not limited thereto, and are an antenna switch module, a transceiver module, and a front-end module. It may be used to detect defects in other multilayer substrates such as laser diode modules, power amplifier modules, SAW diplexers, or electronic components.

  According to the inspection method and the inspection apparatus of the present invention, for example, partial defects or abnormal bonding in a via-hole conductor pillar formed on a multilayer substrate can be particularly suitably detected. In a multilayer substrate, the temperature coefficient of the internal conductor layer or the pattern wiring on the substrate surface is large to some extent, and the method of the present invention functions effectively.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

FIG. 1 is a cross-sectional view of an essential part showing an example of a multilayer substrate according to an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of an inspection apparatus for detecting defects in the multilayer substrate shown in FIG.
FIG. 3 is a flowchart showing the processing contents of the measurement processing / determination unit in the inspection apparatus shown in FIG.

  As shown in FIG. 1, a multilayer substrate 2 as an example of an electronic component has a structure in which a plurality of internal conductor layers 4 are partitioned by interlayer insulating layers 6. Via-hole conductor pillars 8 formed in the interlayer insulating layer 6 establish electrical continuity between the adjacent inner conductor layers 4 or between the inner conductor layer 4 and the external pad portion 10.

The interlayer insulating layer 6 in the multilayer substrate 2 is not particularly limited. For example, a low melting point glass layer such as borosilicate glass, MgO—Al ₂ O ₃ —SiO ₂ glass, CaO—Al ₂ O ₃ —SiO ₂ glass, or the like. Or an insulating layer such as glass epoxy. Further, the inner conductor layer 4 is not particularly limited, and is composed of Ag, Cu, Au, Ag—Pd, Ag—Pt, Ag—Pd—Pt, Pd—Pt, or the like.

  When the multilayer substrate 2 is manufactured, via holes corresponding to the conductor columns 8 in the via holes are formed in the insulating sheet to be the interlayer insulating layer 6, and a conductor is embedded in the via holes. Thereafter, the insulating sheet is pressed onto the core substrate, a window opening process (for example, blasting) at the entrance of the via hole is performed, and then the inner conductor layer 4 is formed by electroless plating or the like. At the same time, the electroless plating layer also enters the entrance of the via hole, and the via hole inner conductor column 8 and the inner conductor layer 4 are connected. By repeating these steps, a multi-layer substrate in which a plurality of internal conductor layers 4 are laminated via an interlayer insulating layer 6 is obtained. The connection between the via-hole conductor pillar 8 and the pad portion 10 is performed in the same manner as the connection between the via-hole conductor pillar 8 and the inner conductor layer 4.

  In the manufacturing process of the multilayer substrate 2, it is ideal that no defect or the like occurs, but a defective portion 20 may occur for some reason. The defective portion 20 may be generated between the pad portion 10 (the same applies to the internal conductor layer 4) and the conductor column 8 for reasons such as incomplete blasting. The defective portion 20 is difficult to find by the conventional measuring method. This is because the defect portion 20 allows normal resistance to be measured between the pair of pads 10 through a relatively low measurement current in the conventional measurement method.

  In the inspection method using the inspection apparatus according to the embodiment of the present invention, the defect 20 is not completely defective in this way, but the defect 20 whose conduction path is partially narrowed is also accurately detected. Can be detected. Details will be described below.

  First, an inspection apparatus according to an embodiment of the present invention will be described. As shown in FIG. 2, the inspection device 30 of this embodiment is a four-terminal method inspection device having four terminals 32 and 34. The inspection device 30 includes a constant current source 36, a voltage measurement unit 38, and a measurement processing / determination unit 40. The measurement processing / determination unit 40 corresponds to the first resistance calculation means, the second resistance calculation means, and the defect detection means in the present invention, and has the function shown in FIG.

  A pair of pad portions 10 shown in FIG. 2 to be measured are, for example, a pair of pad portions 10 in the multilayer substrate 2 shown in FIG. 1, and the pair of pad portions 10 includes a pair of current application terminals 32, A pair of voltage measurement terminals 34 are detachably and electrically connected. The pair of current application terminals 32 are connected to a constant current source 36, and the pair of voltage measurement terminals 34 are connected to a voltage measurement unit 38. The constant current source 36 can switch and apply at least two of the first current I1 and the second current I2.

  The terminals 32 and 34 are supported by a drive mechanism that drives in the X-axis, Y-axis, and Z-axis directions, and are controlled to move in the X-axis, Y-axis, and Z-axis directions according to a predetermined program.

  When these four terminals 32 and 34 are connected to an arbitrary pair of pads 10 to be measured and the inspection by the inspection device 30 starts, the first current is changed from step S1 to step S2 shown in FIG. I1 is applied between the pair of pad portions 10 from the constant current source 36. The first current I1 is a constant current in the range of 1 to 10 mA, for example, and the application time is about 0.001 to 0.050 seconds. With this current I1, heat is hardly generated in the defect 20 shown in FIG.

  Next, in step S3 shown in FIG. 3, the first voltage V1 when the first current is applied is measured. The first voltage V1 is measured by the voltage measuring unit 38 through the pair of terminals 34 shown in FIG. Next, in step S4 (first resistance calculation means), the first resistance R1 is obtained by dividing the first voltage V1 by the first current I1 in the measurement processing / determination unit 40 shown in FIG.

  Next, in step S <b> 5 shown in FIG. 3, the second current I <b> 2 is applied between the pair of pad portions 10 from the constant current source 36. The second current I2 is, for example, a constant current of 500 mA or more, preferably 1 mA or more, and the application time is about 0.100 to 3.000 seconds. With this current I2, the defect 20 shown in FIG. 1 generates heat, for example, at 400 ° C. or higher.

  Next, in step S6 shown in FIG. 3, the second voltage V2 when the second current is applied is measured. The second voltage V2 is measured by the voltage measuring unit 38 through the pair of terminals 34 shown in FIG. Next, in step S7 (second resistance calculating means), the second resistance R2 is obtained by dividing the second voltage V2 by the second current I2 in the measurement processing / determination unit 40 shown in FIG. The second resistor R2 is higher than the first resistor R1 due to heat generation when there is a defective portion 20.

  Next, in step S8, the difference between the second resistance and the first resistance (R2-R1) = x, or the ratio of the difference between the second resistance and the first resistance with respect to the first resistance ((R2-R1) / R1) = x is obtained. Next, in step S9 (defect detection means), the difference between the second resistance and the first resistance (R2-R1) = x, or the ratio of the difference between the second resistance and the first resistance with respect to the first resistance (( It is checked whether R2−R1) / R1) = x is larger than a predetermined value α. Here, x corresponds to the amount of change between the second resistance (R2) and the first resistance (R1).

  When the change amount x is larger than the predetermined value α, it is determined that heat is generated in the defective portion 20, and an alarm indicating that the product is defective is displayed in step S10. Conversely, if the resistance change amount x (difference or ratio) is less than or equal to the predetermined value α, there is no heat generation, and it can be determined that there is no defective portion 20 at step S11.

  When the amount of change x is expressed by a resistance value difference (R2−R1), the predetermined value α can be set, for example, in a range of 0.3 to 0.8 mΩ. Further, when the amount of change x is expressed as a rate of change in resistance value ((R2-R1) / R1), the predetermined value α can be set in a range of 0.055 to 0.145, for example. .

  In the conventional method, when the resistance of the abnormal resistance portion is 0.5 mΩ in the defective portion 20 and the variation value in the process is equal to or higher than this, this abnormal portion cannot be detected.

In the method of the embodiment of the present invention, assuming that the resistance temperature coefficient of the conductor portion is 4 × 10 ^{−3 and the} vicinity of the abnormal portion of the defective portion 20 is locally about 400 ° C. due to the large second current I 2, The second resistor R2 at that time can be expressed by the following equation (1).

R2 = 0.5 × 10 ⁻³ × (1 + 4 × 10 ⁻³ × (400-25)) = 1.25 × 10 ⁻³ Ω (1)
The resistance R1 at the first current I1 is 0.1 × 10 ⁻³ Ω. That is, due to heat generation, a resistance change (difference in resistance value) of about 0.5 mΩ occurs at an abnormal portion of the defective portion 20. By detecting this change in resistance, it is possible to detect an abnormal part.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

FIG. 1 is a cross-sectional view of an essential part showing an example of a multilayer substrate according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of an inspection apparatus for detecting defects in the multilayer substrate shown in FIG. FIG. 3 is a flowchart showing the processing contents of the measurement processing / determination unit in the inspection apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Multilayer board | substrate 4 ... Internal conductor layer 6 ... Interlayer insulation layer 8 ... Conductor pillar in via hole 10 ... Pad part 20 ... Defect location 30 ... Inspection apparatus 32, 34 ... Terminal 36 ... Constant current source 38 ... Voltage measurement part 40 ... Measurement Processing / determination unit

Claims (9)

A method for inspecting a multilayer substrate having at least a first pad portion and a second pad portion connected to the first pad portion through a conduction path,
A first current is passed between the first pad portion and the second pad portion, a first voltage generated between these pad portions is measured, and these pads are based on the first current and the first voltage. Calculating a first resistance (R1) between the sections;
A second current that is 20 times greater than the first current is passed between the first pad portion and the second pad portion, a second voltage generated between these pad portions is measured, and the second current is measured. Calculating a second resistance (R2) between these pad portions based on the current and the second voltage;
A method for inspecting a multilayer substrate, comprising: detecting a defect based on a relationship between the second resistance (R2) and the first resistance (R1).   The method for inspecting a multilayer substrate according to claim 1, wherein a defect is determined to be present when a difference (R2-R1) between the second resistance and the first resistance is equal to or greater than a predetermined value.   2. The multilayer substrate according to claim 1, wherein a defect is determined to be present when a ratio ((R 2 −R 1) / R 1) between the second resistance and the first resistance with respect to the first resistance is equal to or greater than a predetermined value. Inspection method.   In the case where a defective portion exists between the first pad portion and the second pad portion, the first current is a current value that does not generate heat in the defective portion, and the second current is the defect The inspection method for a multilayer substrate according to any one of claims 1 to 3, wherein the current value is such that the portion generates heat.   The multilayer substrate inspection method according to claim 4, wherein the first current is a constant current within a range of 1 to 10 mA, and the second current is a constant current of 500 mA or more.   The terminal for applying the first current and the second current is different from the terminal for measuring the first voltage and the second voltage, and the measuring device has a total of four terminals. 6. The inspection method for a multilayer substrate according to any one of 5 above.   The inspection method of a multilayer substrate according to claim 1, wherein the conduction path includes via-hole conductor pillars formed in the multilayer substrate. A method for inspecting an electronic component having at least a first pad part and a second pad part connected to the first pad part through a conduction path,
A first current is passed between the first pad portion and the second pad portion, a first voltage generated between these pad portions is measured, and these pads are based on the first current and the first voltage. Calculating a first resistance (R1) between the sections;
A second current that is 20 times greater than the first current is passed between the first pad portion and the second pad portion, a second voltage generated between these pad portions is measured, and the second current is measured. Calculating a second resistance (R2) between these pad portions based on the current and the second voltage;
A method for inspecting an electronic component, comprising: detecting a defect based on a relationship between the second resistance (R2) and the first resistance (R1). An inspection apparatus for inspecting an electronic component having at least a first pad part and a second pad part connected to the first pad part through a conduction path,
A first current is passed between the first pad portion and the second pad portion, a first voltage generated between these pad portions is measured, and these pads are based on the first current and the first voltage. First resistance calculating means for calculating a first resistance (R1) between the sections;
A second current that is 20 times greater than the first current is passed between the first pad portion and the second pad portion, a second voltage generated between these pad portions is measured, and the second current is measured. Second resistance calculating means for calculating a second resistance (R2) between these pad portions based on the current and the second voltage;
An electronic component inspection apparatus comprising defect detection means for detecting a defect based on a relationship between the second resistance (R2) and the first resistance (R1).

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