JP2011149790A - Substrate connection inspection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate connection inspection apparatus capable of easily measuring a substrate section to be measured having a different electrode arrangement as an object to be measured. <P>SOLUTION: The substrate connection inspection apparatus 1 includes a TDR measuring device 3, a signal distribution substrate section 5, and a relay board section 21. The signal distribution substrate section 5 includes a signal distribution substrate main body 7, relay board probes 9, and a high-frequency relay 11. The relay board section 21 includes a relay board main body 23 and probes 24 for a substrate to be measured. The probes 24 for a substrate to be measured are arranged correspondingly to the arrangement of electrodes 37 formed in a substrate section to be measured 31 to be an object to be measured. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a substrate connection inspection apparatus, and more particularly to a substrate connection inspection apparatus for inspecting a connection portion between a mounting substrate on which a semiconductor device is mounted and a semiconductor device.

  One form of a semiconductor device package is a ball grid array (BGA). In the ball grid array, solder balls are arranged in a grid shape on the bottom surface of the package, and connection with a printed circuit board or the like is performed via the solder balls. Another form is SOJ (Small Outline J-leaded). In SOJ, a plurality of leads protruding from opposite sides of a package are bent inward toward the bottom surface of the package, and the bent portions are soldered to a printed wiring board.

  In such a package, the connection state of the connection portion with the printed circuit board (mounting substrate) by solder cannot be visually confirmed, and, for example, inspection by X-ray is performed. However, with X-rays, the scanning accuracy is rough, and it is extremely difficult to find a connection failure location due to a minute crack or the like of a connection portion to be actually inspected.

  Therefore, electrical inspection has become increasingly important as a method for inspecting the connection portion between such a package and a printed circuit board. For example, Patent Document 1 proposes a soldering inspection apparatus using TDR (Time Domain Reflectmetry). In the inspection method using TDR, a steep rising pulse wave is applied to a printed circuit board on which a package is mounted via a high-frequency probe, and the connection reliability of a connection part such as a solder ball is inspected by its reflection characteristics. Will be.

  In order to measure a large number of BGAs and circuits on a printed circuit board, the measurement time is shortened by using a multi-pin probe having a pin count of 100 pins or more and measuring in a lump. Further, the output of the TDR measuring device has one to two channels, and by switching and distributing this output, a pulse wave is sent to pins (probes) that exist about several hundreds. A relay is mainly used for switching the output. The probe is manufactured so as to correspond to the electrode structure (arrangement) of the printed circuit board to be measured. In addition to this TDR measurement method, there is an inspection method using boundary scan.

JP-A-9-61486

  A conventional board connection inspection apparatus includes a TDR measuring instrument that measures electrical characteristics, and a signal distribution board unit that distributes and outputs a pulse signal sent from the TDR measuring instrument. A probe corresponding to the electrode arrangement of the printed circuit board to be measured is arranged on the signal distribution board unit. Therefore, as the signal distribution board part, it is necessary to prepare a signal distribution board part for each measurement object corresponding to the electrode arrangement of the printed circuit board. The signal distribution board unit is equipped with a high-frequency relay that distributes pulse signals. The signal distribution board part and the TDR measuring instrument are connected by a coaxial cable. There are dozens of connection points between the coaxial cable and the signal distribution board.

  For this reason, if it is going to measure the printed circuit board from which electrode arrangement differs and it is going to replace a signal distribution board part, it will take time for the removal and attachment work of a coaxial cable and a signal distribution board part. Also, it takes time to set a new signal distribution board.

  An object of this invention is to provide the board | substrate connection inspection apparatus which can perform the measurement of the to-be-measured board | substrate part containing the printed circuit board which has different electrode arrangement | positioning as a measuring object easily.

  The board connection inspection apparatus according to the present invention includes a measuring instrument main body, a signal distribution board section, and a relay board section. The signal distribution board part is electrically connected to the measuring instrument main body and distributes a signal sent from the measuring instrument main body. The relay board part is disposed between the signal distribution board part and the board part to be measured for measurement. The signal distribution board part includes a plurality of first probes that are electrically connected to the relay board part. The relay board part is electrically connected to the relay board body electrically connected to the plurality of first probes, and is arranged to correspond to the arrangement of the electrodes of the board part to be measured related to the measurement. And a plurality of second probes that respectively contact predetermined electrodes.

  According to the board connection inspecting apparatus according to the present invention, when a board part to be measured of different types is to be measured, it is only necessary to replace the relay board part corresponding to the type, and complicated replacement work of the signal distribution board part There is no need to do. As a result, it is possible to easily measure more types of measured substrate portions as measurement targets.

It is a disassembled front view which shows the board | substrate connection inspection apparatus which concerns on embodiment of this invention. In the same embodiment, it is a bottom view which shows a signal distribution board | substrate part. In the same embodiment, it is the partial top view which shows the relay substrate section. FIG. 4 is a partial cross-sectional view taken along a cross-sectional line IV-IV shown in FIG. 3 in the same embodiment. In the same embodiment, it is the partial bottom view which shows the signal distribution board section. In the same embodiment, it is a front view for demonstrating the test | inspection method by a board | substrate connection test | inspection apparatus. In the same embodiment, it is a graph which shows the pulse signal sent from a TDR measuring device. In the embodiment, it is a graph which shows an example of the measurement result of a reflected wave. In the same embodiment, it is a graph which shows the one aspect | mode of the shift | offset | difference of the reflected waveform with respect to a reference waveform. In the same embodiment, it is a graph which shows the other aspect of the shift | offset | difference of the reflected waveform with respect to a reference waveform. In the same embodiment, it is a figure which shows the other example of the arrangement structure of a relay board probe.

  A substrate connection inspection apparatus according to an embodiment of the present invention will be described. As shown in FIG. 1, the board connection inspection apparatus 1 includes a TDR measuring device 3, a signal distribution board part 5, and a relay board part 21. The signal distribution board unit 5 includes a signal distribution board body 7, a relay board probe 9, and a high-frequency relay 11, and the relay board part 21 includes a relay board body 23 and a measured board probe 25.

  The structure of each part will be described in detail. As shown in FIGS. 1 and 2, in the signal distribution board unit 5, the high frequency wiring 13 is formed on one surface of the signal distribution board body 7, and the high frequency relay 11 is mounted. A relay board probe 9 is erected on the other surface of the signal distribution board body 7. The pulse signal sent from the TDR measuring instrument 3 is branched by the high frequency relay 11, and the branched pulse signal is sent to the corresponding relay board probe 9 via the high frequency wiring 13.

  The high frequency wiring 13 is formed in a single layer form on the surface of the signal distribution board 5 on which the high frequency relay 11 is mounted without being divided into a plurality of layers (multilayer wiring). This is to prevent as much as possible the deterioration of the pulse signal due to the high-frequency pulse signal flowing between the multilayer wirings via the vias. As the wiring structure of the high-frequency wiring 13, a wiring structure using either a microstrip line or a strip line is desirable. The high frequency wiring 13 and the relay board probe 9 are electrically connected by a via 15 penetrating the signal distribution board body 7.

  The relay board probe 9 is a probe that electrically connects the signal distribution board unit 5 and the relay board unit 21. As shown in FIGS. 3, 4 and 5, the relay substrate probe 9 is arranged such that, for example, one signal probe 9a is sandwiched between two GND probes 9b fixed to the ground potential. The GSG structure is adopted. In the board connection inspection apparatus 1, one end of the relay board probe 9 can be contracted, and the other end is erected on the signal distribution board body 7.

  In the relay substrate portion 21, an electrode 23 is formed on one surface of the relay substrate body 22. The electrode 23 is formed so as to correspond to the arrangement of the relay substrate probe 9. At the time of measurement, one end of the relay substrate probe 9 comes into contact with the electrode 23. A high-frequency wiring 26 is formed on the other surface of the relay board main body 22, and a measured substrate probe 24 is erected on the high-frequency wiring 26. As the wiring structure of the high-frequency wiring 26, a wiring structure using one of a microstrip line and a strip line is desirable.

  As shown in FIG. 1, the measured substrate probe 24 is disposed so as to correspond to the arrangement of the electrodes 37 formed on the measured substrate portion 31 including the printed wiring board to be measured. The high frequency wiring 26 and the electrode 23 are electrically connected by a via 25 penetrating the relay substrate body 22. In the board connection inspection apparatus 1, one end of the board probe 24 to be measured can be contracted, and the other end is fixed to the relay board body 22. The electrode 23 is formed as a land of the via 25.

  In the measurement target substrate portion 31 to be measured, a ball grid array IC 35 is soldered to one surface of a measurement target substrate body 33 such as a printed wiring board. An electrode 37 that is electrically connected to a predetermined solder ball of the ball grid array IC 35 is formed on the other surface of the substrate body 33 to be measured.

  Next, each probe will be described in more detail. First, the measured substrate probe 24 is arranged in correspondence with the arrangement of the electrodes 37 of the measured substrate portion 31. The measured substrate unit 31 is a printed circuit board to be measured, and is a printed circuit board built in a home electric appliance, an in-vehicle product, or the like. These printed boards are not provided with a function for high frequency, and the electrode 37 is not limited to an electrode provided separately for inspection.

  In the substrate connection inspection apparatus 1, not only the electrode 37 but also a via provided for electric wiring of the measured substrate portion 31 or a pad for soldering an electronic component is used. The substrate probe 24 to be measured needs to be arranged corresponding to these arrangements, and it is often difficult to adopt a GSG structure for ensuring high frequency characteristics as the arrangement structure of the substrate probe 24 to be measured. Therefore, it is desirable to apply a probe whose length is as short as possible as the substrate probe 24 to be measured.

  On the other hand, when the pressure (contact pressure) when the measured substrate probe is in contact with the measured substrate portion is low, or due to the strain inherent in the measured substrate body of the measured substrate portion, There may be a case where the measurement substrate portion does not contact well and a contact failure occurs.

  In order to prevent such a contact failure, it is desirable that the substrate probe 24 to be measured can be contracted and its operating length is 1.2 mm or more. In addition, since flux or the like is used in the measured substrate portion 31 when soldering or the like, this flux may adhere to the electrode 37. In such a case, in order to ensure electrical contact, it is necessary to increase the contact pressure of the substrate probe 24 to be measured, and it is desirable that the contact pressure be 0.98 N or more. Because of such restrictions, the measurement substrate probe 24 is preferably a probe having a total length of about 11 mm, an operating length of about 1 to 2 mm, and a contact pressure of 0.98 N to 2.00 N.

  Next, the relay board probe 9 is a probe that electrically connects the signal distribution board unit 5 and the relay board unit 21. In the signal distribution board part 5 and the relay board part 21, a dedicated gold-plated pad that is not contaminated is applied as a pad. Further, a structure in which high frequency characteristics are maintained is applied as the structure of the electrode. Furthermore, the distortion inherent in each of the signal distribution board body 7 and the relay board body 22 can be used in a small state. For this reason, the contact pressure of the relay substrate probe 9 can be arbitrarily selected, and the options are wider than those of the measured substrate probe.

  Next, the measurement of the board part to be measured by the board connection inspection apparatus described above will be described. As shown in FIG. 6, when performing measurement, first, the relay board probe 9 of the signal distribution board unit 5 is in contact with the electrode 23 of the corresponding relay board part 21 so that the relay board is connected to the signal distribution board part 5. Part 21 is attached. At this time, the length of the relay board probe 9 is adjusted by the relay board probe length adjusting mechanism 17 including the spring 19 as necessary.

  Next, the measured substrate portion 31 is attached to the relay substrate portion 21 such that the measured substrate probe 24 of the relay substrate portion 21 contacts the corresponding electrode 37 of the measured substrate portion 31, and the substrate holding mechanism 41 The measured substrate portion 31 is biased toward the relay substrate portion 21. At this time, the length of the measured substrate probe 24 is adjusted by the measured substrate probe length adjusting mechanism 27 including the spring 28.

  Next, as shown in FIG. 7, a pulse signal 51 rising at a high speed is generated from the TDR measuring device 3, and the generated pulse signal 51 is measured on the relay board probe 9 of the signal distribution board unit 5 and the measurement target of the relay board unit 21. It passes through the substrate probe 24 and is sent to the measured substrate portion 31. In the measured substrate probe 24, the voltage returned by reflecting the pulse signal sent to the measured substrate portion 31 is simultaneously detected, and the reflected waveform is observed by the TDR measuring device 3 based on the detected voltage. The The quality of the measured substrate portion is determined by the observed reflected waveform. That is, if the reflection waveform of the measurement target substrate portion measured in advance is not deviated from the reflection waveform of the measurement target substrate portion measured, the measurement target substrate portion is determined to be non-defective.

  Here, the deviation of the reflected waveform will be described. As shown in FIG. 8, in the reflected waveform measured by the TDR measuring device 3, the vertical axis is voltage and the horizontal axis is time. When determining whether the product is a non-defective product or a defective product, both the voltage and the time are determined, and when either the voltage or the time is deviated from the reflected waveform of the non-defective product (deviation 53), The measured substrate portion is determined as a defective product.

  Since the reflected waveform is measured by the TDR measuring instrument 3, if the path length 52 (see FIG. 7) of the measurement system changes, a time shift 53 (see FIG. 8) occurs in the measured reflected waveform. In measurement using TDR, distance accuracy and time accuracy of the measurement system are important. This is because if the arrival time of the pulse signal to the measured substrate portion 31 changes, even if the measured substrate portion to be measured is a non-defective product, this measured substrate portion Is determined as a defective product.

  In actual measurement, the line length 52 of the measurement system changes due to thermal expansion depending on conditions such as temperature. In addition, since the TDR measuring instrument 3 itself, which is a pulse generation source, also uses a semiconductor switch, the timing at which the pulse signal rises may deviate depending on the temperature. These cause the reflected waveform to shift in the time axis direction.

  The pulse signal output from the TDR measuring device 3 propagates between the TDR measuring device 3 and the measured substrate portion 31 (measurement system line) at a speed at which the electromagnetic wave propagates and reaches the measured substrate portion 31. To do. On the other hand, the reflected wave reflected by the measured substrate portion 1 propagates through the same measurement system line as the pulse signal and reaches the TDR measuring device 3.

  Here, when the propagation speed of the electromagnetic wave is a (m / s) and the line length of the measurement system is b (m), the reflected wave is observed by the TDR measuring instrument 3 after the pulse signal is output from the TDR measuring instrument 3. The time t (s) until the determination is obtained by the relational expression t = a × 2b. This relational expression shows that even if the length (distance) of the measurement line changes or the rise timing (time) of the pulse signal changes, the change is an error that causes the reflected waveform to shift in the time axis direction. It means to become.

  Such a change greatly affects the pass / fail judgment of the measured substrate portion based on the reflected waveform of the reflected wave observed by the TDR measuring device 3. On the other hand, if the software algorithm is changed so that such a change (error) has a margin in the time axis direction, the measurement accuracy is lowered by the margin.

In the board connection inspection apparatus 1 described above, by setting the length of the relay board probe 9 to a predetermined length within the range of the operating length, the length (distance) of the measurement system line and the rise timing of the pulse signal This can be corrected for changes in (time). From the measurement experience, the margin width is required to be about 20p. When the speed of light traveling is 2.998 × 10 ¹¹ mm / s, the length (distance) corresponding to 20 pS in time is about 3 mm. Then, the operating range of the relay board probe 9 is required to be 3.5 mm or more.

  Here, an example of correction by changing the length of the relay board probe 9 will be described. The length of the relay probe 9 is adjusted so that the reflection waveform observed by measuring the non-defective measurement target substrate overlaps the reference waveform using the reflection waveform of the non-defective measurement target substrate portion as a reference waveform. First, as shown in FIG. 9, when the measured reflected waveform 62 is observed to be shifted in the negative direction of the time axis with respect to the reference waveform 61, the reflected waveform is shifted in the positive direction of the time axis. In order to match the reference waveform, the relay board probe length adjustment mechanism 17 adjusts the length of the relay board probe 9 to be longer. On the other hand, as shown in FIG. 10, when the reflected waveform 62 to be measured is observed to be shifted in the positive direction of the time axis with respect to the reference waveform 61, the reflected waveform is shifted in the negative direction of the time axis. In order to match the reference waveform, the relay board probe length adjustment mechanism 17 adjusts the length of the relay board probe 9 to be shorter.

  Since the relay board probe 9 becomes a part of the line of the measurement system, it is necessary to match its characteristic impedance to the characteristic impedance of the measurement system. In the board connection inspection apparatus 1 described above, a GSG structure is adopted as an arrangement structure of the relay board probe 9 that matches the characteristic impedance. By adjusting the length of all the relay substrate probes 9 having the GSG structure by the same amount at the same time, the characteristic impedance is maintained regardless of the operating length. The length of the relay board probe 9 is determined by tightening or loosening the nut of the relay board main body 22 that is biased in a manner separated from the signal distribution board main body 7 by the spring 19 as the relay board probe length adjusting mechanism 17. By changing the distance between the signal distribution board body 7 and the relay board body 22, the length is adjusted to a predetermined length.

  According to the board connection inspection apparatus 1 described above, in addition to the signal distribution board part 5 for achieving such impedance matching, the relay board part 21 corresponding to the type of the board part to be measured is provided, and the relay board is provided. The portion 21 is interposed between the measured substrate portion 31 and the signal distribution substrate portion 5. Thus, when measuring different types of board parts to be measured, it is only necessary to replace the relay board part 21 corresponding to the type, and the coaxial cable and the signal distribution board part are removed and attached. This eliminates the need for complicated replacement work for the signal distribution board section. As a result, it is possible to easily measure more types of measured substrate portions as measurement targets.

  In addition, in this board connection inspection apparatus 1, since the high frequency relay for distributing the high frequency signal is required, the signal distribution board portion 5 that requires cost can be shared. As a result, many types of substrate parts to be measured can be measured at a lower cost. Further, since it is not necessary to apply a multilayer substrate as the signal distribution substrate unit 5, wiring is not complicated with the multilayer structure, and the high frequency characteristics are not deteriorated.

  Furthermore, the board connection inspection apparatus 1 described above includes a relay board probe length adjusting mechanism 17 that changes the length of the relay board probe 9. As a result, the relay substrate probe length adjustment mechanism 17 causes the reflected waveform of the non-defective measured substrate portion to match the reference waveform with respect to the change in the line length 52 of the measurement system and the change in the rise timing of the pulse signal. The length of the relay board probe 9 is adjusted. As a result, it is not erroneously determined that the measured substrate portion, which is originally a good product, is a defective product, and a more accurate non-defective product can be determined.

  In the above-described board connection inspection apparatus 1, the relay board probe length adjustment mechanism 17 has been described by taking as an example the case where the length of the relay board probe 9 is adjusted by the tightening amount of the nut. For example, the length of the relay board probe 9 may be adjusted using a mechanical stage.

  Further, as an arrangement structure of the relay substrate probe 9, the GSG structure has been described as an example. The arrangement structure of the relay board probe 9 is not limited to the GSG structure as long as it can match the characteristic impedance of the relay board probe 9 to the characteristic impedance of the measurement system. A structure in which a GND probe fixed to the ground potential is disposed at a point-symmetrical position with respect to the signal probe to which the pulse signal is transmitted among the relay substrate probes 9 may be employed. With such an arrangement structure, the number of GND probes can be two, four, or six or more.

  In addition, as shown in FIG. 11, a plurality of GND probes 9d may be arranged at equal intervals (distance 73) along a circumference 71 centered on the signal probe 9c. High frequency characteristics can be improved by providing as many GND probes 9d as possible in a region. Further, as the relay board probe, the relay board probe 9 whose one end can be contracted and whose other end is fixed to the signal distribution board body 7 has been described as an example. May be applied. Also, the measured substrate probe has been described by taking the measured substrate probe 24 whose one end can be contracted and the other end fixed to the relay substrate main body 22 as an example, but both ends can be contracted. A substrate probe to be measured may be applied.

  The embodiment disclosed this time is an example, and the present invention is not limited to this. The present invention is defined by the terms of the claims, rather than the scope described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is effectively used for inspection of a connection portion between a mounting substrate on which a semiconductor device is mounted and the semiconductor device.

  DESCRIPTION OF SYMBOLS 1 Board | substrate connection inspection apparatus, 3 TDR measuring device, 5 Signal distribution board part, 7 Signal distribution board main body, 9 Relay board probe, 9a Signal probe, 9b GND probe, 9c Signal probe, 9d GND probe, 11 High frequency relay, 13 High frequency Wiring, 15 via, 17 relay board probe length adjustment mechanism, 19 spring, 21 relay board section, 22 relay board body, 23 electrodes, 24 board probe to be measured, 25 via, 26 high frequency wiring, 27 board board length to be measured Adjustment mechanism, 28 spring, 31 measured substrate part, 33 measured substrate body, 35 ball grid array IC, 37 electrodes, 41 substrate holding mechanism, 51 pulse signal, 52 measurement system line length, 53 deviation, 61 reference waveform, 62 Measurement waveform, 71 circumference, 73 distance.

Claims (5)

A measuring instrument body,
A signal distribution board portion that is electrically connected to the measuring instrument main body and distributes a signal sent from the measuring instrument main body;
A relay board portion disposed between the signal distribution board portion and the board portion to be measured related to measurement,
The signal distribution board part includes a plurality of first probes electrically connected to the relay board part,
The relay board part is
A relay board body electrically connected to the plurality of first probes;
A board connection inspection comprising a plurality of second probes that are electrically connected to the relay board main body and are arranged so as to correspond to the arrangement of the electrodes of the board part to be measured for measurement, and respectively contact the predetermined electrodes apparatus. Each of the plurality of first probes is
A first end in contact with the electrode of the substrate part to be measured for measurement;
A second end located on the opposite side of the first end;
The first end is contractible;
The board | substrate connection inspection apparatus of Claim 1 provided with the 1st probe length adjustment part which sets the length of the said 1st probe to predetermined length by adjusting the length of the said 1st edge part.   The board connection inspection apparatus according to claim 2, wherein the second end is fixed to the signal distribution board. The plurality of first probes are:
A signal probe for transmitting a signal sent from the measuring instrument body;
A ground potential probe fixed to the ground potential,
The substrate connection inspection apparatus according to claim 1, wherein the ground potential probe is disposed so as to surround the signal probe. In the signal distribution board part, a wiring structure is formed by either a microstrip line or a strip line that sends a signal sent from the measuring instrument main body to the first probe,
5. The wiring structure according to claim 1, wherein a wiring structure is formed by one of a microstrip line and a strip line that sends a signal sent from the first probe to the second probe. Board connection inspection equipment.

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