JP2009244077A - Substrate inspection device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate inspection device, for efficiently detecting electric short circuit caused between content terminals of the substrate inspection device which is to contact with an inspection object substrate, and a method thereof. <P>SOLUTION: The substrate inspection device (50) includes a plurality of pins (contact terminals) (1a-8p) which transmits an inspection signal to a predetermined inspection point of a wiring pattern (2) of a substrate (16) in contact therewith, and inspects the quality of electric characteristics of the wiring pattern through the pins. This device includes a means for checking the pins for electric short circuit between the pins while the substrate is removed, and this means includes a means which repeats to form pin groups by halving the plurality of pins pin groups and to form pin groups by further halving each of the formed pin groups until the pin group is divided into one pin; and a means which checks the pins, each time when the halving is performed, for electric short circuit between the divided pin groups or between the pins, and on and after the second halving, the check between the divided pin groups or between the pins is simultaneously performed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a substrate inspection apparatus and method. More specifically, the present invention relates to a substrate inspection apparatus and method for efficiently detecting occurrence of a short circuit when an electrical short occurs between contact terminals of a substrate inspection apparatus that contacts a conductor pattern of a substrate to be inspected.

  In order to check whether or not an electrical short has occurred between the contact terminals of the substrate inspection apparatus, every time the substrate inspection of one substrate is completed, all contact terminals are sequentially Pairs are inspected for electrical shorts. The reason why such inspection is necessary is that when the contact terminal comes into contact with the inspection point set at a predetermined position on the substrate, the inspection point comes into contact with the contact terminal, thereby forming a foreign object (inspection point on the contact terminal). In particular, when the inspection point is formed of solder, the solder at the inspection point may adhere to the contact terminal and cause an electrical short circuit with the adjacent contact terminal. This is because it may occur. When the contacts arranged at both ends of the wiring are electrically short-circuited in this way, for example, even when the wiring is disconnected, the contacts are in a conductive state and the disconnection of the wiring cannot be detected. There is a bug.

  Here, in the present application documents, “substrate” is a generic term for various substrates such as single-layer or multilayer printed wiring boards, flexible substrates, electrode plates for liquid crystal displays and plasma displays, film carriers, and semiconductor wafers. To do.

  The present inventors do not know the existence of a published patent document or a published non-patent document relating to a method for inspecting the presence / absence of an electrical short between contact terminals of a substrate inspection apparatus as described below.

  On the other hand, with the recent miniaturization of electronic devices and the accompanying increase in the density of substrates, the number of contact terminals used for substrate inspection is several thousand at most. Therefore, 100% inspection between contact terminals requires a great number of inspection points and requires a long time for inspection.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a substrate inspection apparatus and method that can efficiently detect an electrical short generated between contact terminals of a substrate inspection apparatus in contact with a substrate to be inspected.

  In view of the above-described object, a board inspection apparatus according to the present invention has a plurality of pins (contact terminals) that are in contact with a predetermined inspection point of a wiring pattern on a board and transmit an inspection signal, via the pins. In the board inspection apparatus for inspecting the quality of the electrical characteristics of the wiring pattern, the board inspection apparatus includes means for inspecting the presence or absence of an electrical short between the pins with the board removed, the means comprising the plurality of pins Are divided into two to form a pin group, and each formed pin group is further divided into two to form a pin group. And means for inspecting whether there is an electrical short between the divided pin groups or between the pins. After the second division, the divided pin groups or between the pins are simultaneously tested. It is characterized by that.

  Furthermore, the substrate inspection apparatus according to the present invention has a plurality of pins (contact terminals) that are in contact with predetermined inspection points of the wiring pattern of the substrate and transmit inspection signals, and the wiring pattern is electrically connected via the pins. In the substrate inspection apparatus for inspecting the quality of the electrical characteristics, the substrate inspection apparatus includes means for inspecting the presence or absence of an electrical short between the pins or between the pin groups with the substrate removed, and for all the plurality of pins In addition, it is simultaneously inspected whether there is an electrical short between the pins, and the pins that have not been electrically shorted are grouped into one pin group, and the presence of an electrical short between these pin groups is simultaneously inspected, and In this case, a group of pins that are not electrically short-circuited are grouped into a single pin group, and the presence or absence of an electrical short circuit between these pin groups is simultaneously inspected. In minutes And characterized in that the inspection until the.

  Further, in the board inspection apparatus, when the actual total pin number of the plurality of pins is not a multiple of 2, the minimum number is a multiple of 2 that is larger than the actual total pin number and the smallest number is the temporary pin total. The difference between the total number and the actual number of pins is defined as an empty pin, and the presence or absence of an electrical short between pins or between pins is inspected. The inspection between an empty pin and other pins or between empty pins is an electrical short. It can also be processed as none.

  Further, in the board inspection apparatus, the inspection for the presence or absence of an electrical short between the pin groups or between the pins is performed after the normal board inspection for the board is completed and before the normal board inspection for the next board is started. It may be carried out during this period.

  Further, in the board inspection apparatus, for the plurality of pins, a pin number close to a pin that is close in position when fixed by an inspection jig is given, and an inspection relating to a pin having a close pin number is performed. May be implemented at an early stage.

  Further, according to the method of inspecting the presence or absence of electrical shorts between pins according to the present invention, an inspection signal is output by contacting a predetermined inspection point of a wiring pattern at the time of substrate inspection for inspecting the electrical characteristics of the substrate. A method for inspecting the presence or absence of an electrical short between pins for a plurality of pins (contact terminals) to be transmitted, comprising: (a) removing the substrate from the pins; and (b) dividing the plurality of pins into two Forming a pin group which is a group of electrically connected pins, (c) checking for the presence of an electrical short between the pin groups, and (d) further dividing each pin group into two Then, an electrically connected pin group is formed, (e) the presence or absence of an electrical short between the divided pin groups is simultaneously checked, and (f) one of steps (d) to (e) is performed. Repeat until the inspection between pins.

  Further, according to the method of inspecting the presence or absence of electrical shorts between pins according to the present invention, an inspection signal is output by contacting a predetermined inspection point of a wiring pattern at the time of substrate inspection for inspecting the electrical characteristics of the substrate. A method for inspecting the presence or absence of electrical shorts between pins for a plurality of pins (contact terminals) to be transmitted, comprising: (a) removing the substrate from the pins; and (b) attaching all of the plurality of pins to the plurality of pins. On the other hand, the presence or absence of electrical shorts between pins is simultaneously inspected, and (c) the pins that have been identified as having no electrical shorts are grouped into one pin group, and the presence or absence of electrical shorts between these pin groups is simultaneously observed. (D) A group of pins that have been identified as having no electrical shorts are combined into one pin group, and the presence or absence of electrical shorts between these pin groups is simultaneously inspected, and (e) steps (c) to (d) ) Until all the pins are divided into two groups. Return.

  Further, in the method for inspecting the presence or absence of an electrical short between the pins according to the present invention, when the actual total pin number of the plurality of pins is not a multiple of 2, it is a multiple of 2 larger than the actual total pin number. The smallest number is the total number of temporary pins, the difference between the total number of temporary pins and the actual total number of pins is defined as an empty pin, and the presence or absence of an electrical short between pins or between pins is inspected. The inspection between the pins or between the empty pins can be processed as no electrical short.

  Further, in the method for inspecting the presence or absence of an electrical short between pins according to the present invention, the inspection for the presence or absence of an electrical short between the pin groups or between the pins is performed after a normal substrate inspection for the substrate is completed. However, it can be carried out in a period before the start of the normal substrate inspection for the next substrate.

  Furthermore, in the method for inspecting the presence or absence of electrical shorts between pins according to the present invention, the plurality of pins are close to pins that are close in position when fixed by an inspection jig. It is also possible to assign a pin number and perform an inspection on a pin having a similar pin number at an early stage.

  ADVANTAGE OF THE INVENTION According to this invention, the board | substrate inspection apparatus which can detect efficiently the electrical short generate | occur | produced between the contact terminals of the board | substrate inspection apparatus contact | abutted to a to-be-inspected board | substrate, and its method can be provided.

  Hereinafter, embodiments of a substrate inspection apparatus and method according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are assigned to the same elements, and duplicate descriptions are omitted.

[Board inspection]
Substrate manufacturers, after manufacturing a substrate, perform various types of inspections to guarantee the finish of the substrate on a single substrate. As a typical electrical inspection, there are inspections called continuity inspection and short circuit inspection. In the present application documents, these are collectively referred to as “substrate inspection”.

  One of the board inspections is a continuity inspection that confirms that a conductor originally designed so that one end and the other end are electrically connected is formed with a DC resistance value within a predetermined range. This is for detecting defects such as disconnection and thinning of the conductor pattern. Another one of the board inspections is that adjacent conductors that are originally designed not to be electrically connected to each other are not electrically short-circuited (short-circuited) or are electrically above a predetermined resistance value. This is a short-circuit inspection (insulation inspection) for confirming that they are insulated. This is to detect electrical shorts between each conductor, insulation failure, and the like.

  The substrate inspection is performed by a method called a two-terminal method. In the two-terminal method, a plurality of probes of the substrate inspection apparatus are brought into contact with a predetermined plurality of inspection points of the conductor pattern formed on the surface of the substrate, and the conductor pattern is formed between the two selected probes. This is carried out by passing a direct current and obtaining a resistance value with a direct current voltage generated between the probes. The inspection point of the conductor pattern is usually a land provided for soldering or bonding a terminal of a surface mounting type component called a pad, or a solder bump formed on the land.

(4-terminal method)
Here, when the resistance value of the conductor pattern is very small, the conductor resistance of the cable connected to the probe and the contact resistance between the probe and the conductor pattern cannot be ignored, resulting in a measurement error. According to JIS, this measurement error must be within 5%.

  A four-terminal method is a measurement method for preventing errors in this cable and contact resistance. FIG. 1 is a diagram for explaining the four-terminal method. In the four-terminal method, current probes 4-1 and 4-2 for supplying a current to the conductor pattern 2 and voltage probes 6-1 and 6-2 for detecting a voltage generated from the conductor pattern 2 are separately provided and voltage probes are provided. Measure between.

  Since a constant current is caused to flow by the constant current source 8, a prescribed current is not affected by the conductor resistance of the cables 4-1 and 4-2 on the current side and the contact resistance between the probe and the conductor pattern 2. Flowing into. The input impedance of the voltage detector 9 is much higher than the resistance R2 of the conductor pattern to be inspected, the conductor resistance of the cable on the detection side, and the contact resistance between the voltage probes 6-1 and 6-2 and the conductor pattern 2 to be inspected. If it is increased, the voltage drop due to these resistors can be ignored, and the voltage generated between the two voltage probes 6-1 and 6-2 can be accurately measured. From the measured voltage V and the current flowing through the conductor pattern I, the resistance R2 (= V / I) of the conductor to be inspected can be calculated.

  As shown in FIG. 2, in order to inspect the substrate 16 having such a high-density wiring pattern by a four-terminal method, the current probe and the voltage probe are combined (FIG. 2A) or integrated into one contact. 10 (FIG. 2B), and an inspection jig (see FIGS. 7 and 8, reference numerals 58u and 58d) in which a plurality of contacts are integrated is employed. In this application document, the current probe or voltage probe is referred to as “contact terminal” or “pin”, and the current probe and voltage probe that are integrated or paired are referred to as “contact”.

  Typically, two pins (a current pin and a voltage pin) that are electrically isolated from each other are formed. The two pins are, for example, a pair of pins 12-1 and 12-2 arranged in parallel as shown in FIG. 2A, or a core pin 12-4 as shown in FIG. 2B. And an annular pin 12-3 surrounding it is integrally formed with one contact 10-1.

  In addition, it is not necessary to perform the board | substrate test | inspection of all the wiring patterns of the board | substrate 16 by a four terminal method. If the presence of errors in cables and contact resistance is not a problem, the two-terminal method is adopted, and actual inspection is performed by appropriately combining the two-terminal method and the four-terminal method. The method for detecting an electrical short between pins described below is adopted in both cases of the four-terminal method and the two-terminal method, and is not particularly limited to the two-terminal method or the four-terminal method.

[Detection of electrical short between pins]
In recent years, due to the demand for high-density mounting of substrates due to miniaturization of electronic devices, wiring patterns have become high-density, and surface-mounting types tend to be adopted as mounting components. Therefore, the inspection point is often a solder bump 20 formed on a land 18 provided for soldering or bonding a terminal of a surface mount type component in addition to a land of a wiring pattern.

  At the time of substrate inspection, an inspection jig (see FIGS. 7, 858u, 58d) having a plurality of contact terminals 12-1, 12-2 arranged closely is positioned with respect to the substrate 16 to be inspected. The inspection jig is brought close to the board 16 to be inspected, and the contact terminals 12-1 and 12-2 are brought into contact with the inspection points of the corresponding board 16 to be inspected. As a result, each of the contact terminals 12-1 and 12-2 comes into contact with the solder bump 20 that is a predetermined inspection point, passes a current through the solder bump 20 through the current pin, and passes through the voltage pin. Measure the potential. Recent pin diameters are on the order of tens of microns at most. When the current pin and the voltage pin are integrated and used as a contact, the gap between the two pins 12-1 to 12-2 formed on one contact is very close to a few tens of microns or less. Is arranged. The substrate 16 to be inspected typically has an area of several centimeters square, and several thousand inspection points are set when the area is large within this area.

  Each of the pins 12-1 to 12-2 is made of, for example, a metal such as beryllium copper (BeCu) or tungsten (W) whose periphery is coated with gold. The pins are brought into contact with the solder bumps 20 of the substrate 16 to be inspected, and further contacted. As shown in FIG. 2, the solder bumps 20 formed on the lands 18 are slightly pierced. For this reason, the solder bump 20 is recessed, and when the contact terminals 12-1 and 12-2 are pulled up after the inspection is finished and the pins 12-1 to 12-2 are removed from the solder bump 20, the solder may adhere to the pins. .

  As a result, an electrical short may occur between the pins (between 12-1 and 12-2) due to the solder adhered to the pins. If an electrical short occurs between pins, the next board inspection cannot be performed. For this reason, every time a board inspection of a single board is performed, it is necessary to check whether or not there is solder adhesion so that the pins are electrically short-circuited, that is, a continuity test between the pins.

  In addition, since the distance between adjacent contacts is also short, inspection between two pairs of pins (between 12-1 and 12-2) of one contact terminal (12-1 or 12-2). In addition, it is necessary to perform inspection between pins belonging to adjacent contact terminals. After all, in order to improve the reliability of the inspection, it is necessary to perform a total inspection between the pins. In order to inspect all pins, a very long inspection time is required, and in some cases, it takes a longer time to inspect all pins than the original board inspection.

(Detection method of electrical short between pins)
A method for detecting an electrical short between pins according to the present embodiment will be described by comparing the current method for detecting an electrical short between pins. FIG. 3 is a diagram for explaining a method of 100% inspection between pins currently being performed. Here, for convenience of explanation, it is assumed that the total number of pins 12 is 8,192. Further, in order to facilitate visual understanding, it is assumed that the pins 12 are arranged in a regular manner as shown in the figure. In order to identify the pins, the number of rows is 1, 2,..., 8 and the number of columns is a, b,. The pins 12 arranged in the first row are called 1a, 1b, 1c,..., 1p from left to right, and the pins 12 arranged in the second row are made 2a, 2b, 2c,. Let's call it 2p.

  The inspection currently conducted regarding the presence or absence of an electrical short between pins is a brute force inspection between pins. Specifically, a reference pin is determined, and it is sequentially inspected whether or not an electrical short circuit has occurred between this reference pin and all other pins. The inspection content is a continuity test between pins, that is, whether or not the connection is made at a predetermined resistance value or less. When all other pins have been inspected, set the reference pin as the next pin, and inspect whether or not an electrical short has occurred with other pins, except for the pin already completed. Yes.

  Referring to FIG. 3, for example, first, the pin 1a is set as a reference pin, and the section between (1a)-(1b, 1c, 1d,..., 8p) is inspected. Next, with reference to the pin 1b, the area between (1b)-(1c, 1d, 1e,..., 8p) is inspected. At this time, since 1b-1a has already been inspected at the first stage, re-inspection is not performed. This is repeated, and finally (8o)-(8p) is inspected. Next, pin 1b is set as a reference pin, and inspection is sequentially performed between 1b-1c, 1b-1d,..., 1b-8p.

  When the occurrence of an electrical short is detected during the inspection, the inspection is immediately interrupted and the pin 12 is cleaned. This pin cleaning operation is for removing solder attached to the tip of the pin, for example, rubbing the tip of the pin with a wire brush, blowing clean air at a high pressure, or heating to melt the solder. Or do some of these at the same time. After the cleaning operation, the same inspection is performed again to confirm that the attached solder has been removed and there is no electrical short.

  The present inventors propose the following method in order to greatly reduce the time for this pin-to-all pin inspection. Similar to the conditions described in the current method, the total number of pins is 8,192. Similarly, it is assumed that the contact terminals are arranged in a regular manner for easy visual understanding.

  The first method proposed by the present inventors will be described with reference to FIGS. 4A and 5. As shown in FIG. 4A and FIG. 5A, in the first inspection sequence, the 8,192 pins are divided into two to form two groups of 4,096 pins, and the presence or absence of an electrical short between these 4,096 pin groups is inspected. To do. That is, in this test, pins belonging to the same group are electrically connected in parallel, and a continuity test between the pin groups (that is, a test of whether or not they are connected at a predetermined resistance value or less) is performed. The assignment of the pin number of each pin and the determination of which pin group each pin belongs to are arbitrary and are performed on the inspection program unless otherwise specified. In the inspection, the actual electrical formation of the pin group is performed by a scanner of the substrate inspection apparatus as will be described later.

  Here, if it is determined that an electrical short circuit has not occurred between the 4,096 pin groups, even if an electrical short circuit has occurred between some pins, the electrical short circuit has two 4,096 pins. It occurs between pins belonging to one of the groups, not across two 4,096 pin groups. That is, it is guaranteed that there is no electrical short between the pins belonging to one group and the pins belonging to the other group.

  As shown in FIGS. 4A and 5B, in the second inspection sequence, one of the 4,096 pins is further divided into two to form two groups of 2,048 pins, and an electrical short circuit between these 2,028 pin groups. Check for presence. At the same time, the other 4,096 pins are equally divided into two groups of 2,048 pins, and the presence of an electrical short circuit between these 2,028 pin groups is inspected. That is, the inspection is performed at two locations at the same time. As described above, if it is determined that an electrical short circuit has not occurred between the 2,028 pin groups, even if an electrical short circuit has occurred between any contact terminals, the short circuit is not This occurs between the pins belonging to the pin group, and there is no electrical short across the pin group.

  Similarly, as shown in FIGS. 4A and 5C, in the third inspection sequence, each 2,048 pin group is further equally divided into 1,024 pin groups, and whether there is a short circuit between these 1,024 pin groups. inspect. Conduct inspections at four locations simultaneously.

  Similarly, as shown in FIGS. 4A and 5D, in the fourth inspection sequence, each 1,024 pin group is further divided into two groups of 512 pins, and whether or not there is a short circuit between these 512 pin groups. inspect. Conduct inspections at 8 locations simultaneously.

  This is repeated, and in the thirteenth inspection sequence, each of the two pin groups is divided into two equal parts, and one pin is inspected for the presence or absence of a short circuit. At this time, inspections are performed at 4,096 locations simultaneously.

  Even if one inspection is required for one second, the current method is inspected by shifting the reference pin 1a up to 8o in order, so that an inspection between all the pins requires a very long time of 8,190 seconds. To do. On the other hand, according to the first method, 13 inspections, that is, the inspections are completed in 13 seconds.

  In the method currently being implemented, the first method proposed by the present inventors performs the inspection between pins that have been inspected in total by one by one. In the first method proposed by the present inventors, the inspection is performed substantially between the pin groups. The inspection time can be significantly shortened by completing the inspection between the pins belonging to each time in one time and further increasing the number of simultaneous inspection locations by multiplying the inspection order.

  When an electrical short is detected during the inspection, the inspection is interrupted and the pin is cleaned as described in the current implementation method. After the cleaning operation, the inspection is performed again to confirm that the adhered solder has been removed and the electrical short has disappeared.

  Furthermore, the present inventors propose a second method. The second method is a method of performing inspection by reversing the inspection order of the first method. According to the second method, since there is a high probability that an electrical short will occur between pins that are close to each other, it is possible to detect an electrical short earlier by inspecting such pins at an early stage. It is based on the idea.

  In the second method, as shown in FIG. 4B, in the first inspection order, 4,096 locations are inspected simultaneously between one pin. This inspection is the same as the 13th inspection in the inspection sequence of the first method.

  In the second inspection sequence, the pin-pins that were found to be free of short-circuits in the first inspection are collected into a group of two pins, and the two pin groups thus formed are inspected simultaneously at 2,096 locations. This inspection is the same as the 12th inspection in the inspection sequence of the first method. Similarly, in the third inspection sequence, a group of four pins that are found not to cause a short circuit in the second inspection sequence, and the 1,024 locations between the four-pin groups thus formed are inspected simultaneously. This inspection is the same as the 11th inspection in the inspection sequence of the first method. This is repeated, and the 4,096 pin group is inspected in the 13th inspection order.

  The time required for the inspection of all the pins by the second method is the same as the inspection time of the first method. However, when an electrical short is detected during the inspection, the inspection is interrupted and the pin is cleaned. As will be described below, the second method has a higher probability of detecting occurrence of a short circuit at an earlier stage of the inspection sequence than the first method. That is, it can be expected that the inspection time until the short detection is further reduced as compared with the first method.

  That is, in the second method, an inspection program for inspecting a pair of adjacent pins at an early stage by assigning consecutive pin numbers to a pair of adjacent pins formed on the same contactor 10. Can be created. Further, it is possible to assign a pin number consecutively to the pins belonging to the adjacent contacts, and to inspect the presence / absence of a short circuit for these pins at a relatively early stage. Further, the same effect can be obtained by assigning a relatively close pin number to the pins of the contactor positioned in the vicinity by the inspection jig. By assigning close pin numbers to pins that are close to each other in this way and creating an inspection program for inspecting pins with close pin numbers at an early stage, it is possible to detect occurrence of a short circuit. Time can be further reduced.

  Even in the second method, in the confirmation test without a short circuit performed after the cleaning operation, all the inspection orders 1 to 13 are inspected, and therefore, the inspection time is the same as that of the first method.

  Here, a supplementary explanation will be given regarding the first and second methods. Several assumptions are made in describing the first method and the second method. This premise will be explained in consideration of the actual pin situation.

  In the above description, the number of pins is assumed to be 8,192. Dividing the dividend 8,192 by the divisor 2 gives a quotient of 4,096 with no remainder. Further, when the dividend 4,096 is divided by the divisor 2, the quotient becomes 2,048, and there is no remainder. By repeating this and dividing the sequentially calculated quotient by the divisor 2, it is possible to divide to the end (that is, until the quotient becomes 1), and there is no remainder.

  However, the actual number of pins of the board inspection apparatus is not such a convenient number. A description will be given of what to do when the actual number of pins is, for example, 6,345 or 1,564. When the actual number of pins is 6,345, the minimum number 8,192, which is a multiple of 2 greater than 6,345 and is the total number of pins. At this time, the difference between 8,192 and 6,345 is defined as an imaginary pin, that is, an empty pin. In the program for executing this inspection, the total number of pins is handled as a total of 8,192 (the actual number of pins + free pins).

  When the actual number of pins is 1,564, the minimum number 2,048, which is a multiple of 2 larger than 1,564 and is the total number of pins. At this time, the difference between 2,048 and 1,564 is defined as an imaginary pin, that is, an empty pin, and the total number of pins including the empty pin is handled as 2,048.

  The inspection between the empty pins and other pins or between the empty pins can be executed by executing the first and second methods by treating the inspection program as no short circuit.

  In this way, by introducing the concept of empty pins, the first and second methods are arbitrary by defining the minimum number that is a multiple of 2 larger than the actual number of pins as the total number of pins in the program. It becomes applicable to the number of pins.

  In the above description, the reason why the contact terminals are arranged in a regular manner is to facilitate visual understanding. If only the four-terminal measurement method is used, two actual pins are formed in contact units, and the arrangement of the contacts 10 is determined corresponding to the inspection points of the wiring pattern of the substrate 16 to be inspected. . Even in such a case, by sequentially assigning pin numbers to each pin, pin group formation, pin group division, inspection performed between the pin groups, and the like can be performed according to the above description. .

  Further, the advantage and advantage of the second method is that the pin number close to the position is assigned based on the arrangement of the contact and each contact (that is, the arrangement of the inspection points of the pattern to be inspected), This can be realized by inspecting pins with similar pin numbers early in the inspection program.

  The pin number is an identification symbol of the pin, and an arbitrary symbol may be used in addition to the alphanumeric characters as described above.

(Detection of electrical short between pins and board inspection)
In order to improve the efficiency of board inspection, the short-circuit inspection between pins is performed after the normal board inspection for the board to be inspected and before the start of the normal board inspection for the next board to be inspected. It is preferable to carry out during a period (idle time) when the inspection apparatus is not performing the substrate inspection. This is done during the idle time while the substrate after the inspection is removed, and the substrate for the next inspection is carried in and set at a predetermined inspection position, thereby inspecting a large number of substrates. This is because the processing can be performed efficiently.

  As shown in FIG. 6, the first board inspection is performed in step S01, and when the board inspection is completed in step S11, an inspection block for the presence or absence of an electrical short between pins surrounded by a broken line is entered.

  In step S12, an inspection for the presence of an electrical short between the pins is started. If an electrical short is detected in step S13, the inspection is immediately stopped, and a pin tip cleaning operation is performed in step S14. If no short is detected, the process proceeds to the end of the inspection in step S17.

  After the cleaning operation for the pins, in step S15, a confirmation inspection for confirming that there is no short circuit is started, and in step S16, it is determined whether there is a short circuit. Here again, when a short circuit is detected, the inspection is immediately stopped, and the process returns to step S14 to carry out the cleaning operation of the tip of the pin. If no short is detected and the confirmation inspection is completed to the end, the process proceeds to the end of the inspection in step 17. The above is the procedure for inspecting the presence or absence of an electrical short between pins.

  In step S18, it is determined whether or not it is the last substrate. If it is not the last substrate, the next substrate inspection is performed in step S19. When the substrate inspection is completed in step S20, a short inspection is started in step S12 of the inspection block for the presence / absence of a short circuit between pins surrounded by a broken line. If it is the last substrate, the process ends.

[Board inspection equipment]
Next, a substrate inspection apparatus that performs a normal substrate inspection and an inspection for the presence or absence of an electrical short between pins will be briefly described.

  FIG. 7 is a side sectional view of the entire substrate inspection apparatus, FIG. 8 is an explanatory view of the electrical configuration of the substrate inspection apparatus, and FIG. 9 is an explanatory view of the configuration of the scanner of the substrate inspection apparatus.

  As shown in FIG. 7, the substrate inspection apparatus 50 includes a plurality of contacts (current pins and voltage pins are formed on each contact) above and below the substrate 16 to be inspected fixed to the transfer table 60. .) Inspection jigs 58u and 58d in which 10 are bundled and fixed are arranged. Since the inspection jigs 58u and 58d are the same, the upper inspection jig will be described. As shown in FIG. 8, the inspection jig 58u can be moved and positioned in the X, Y, Z, θ (rotation around the Z axis) direction by the inspection jig driving mechanism 56u.

  As shown in FIG. 8, the substrate inspection apparatus 50 receives a control unit 76 that controls the operation of the entire apparatus in accordance with an inspection program stored in advance in a storage device (not shown), and an inspection start command from the control unit. And a tester controller 74 for sequentially selecting predetermined contacts 10 according to the inspection program and outputting a scan command to the scanner 72.

  As shown in FIG. 9, the scanner 72 includes an inspection processing unit 82 and a changeover switch 80. The inspection processing unit 82 sequentially selects predetermined pins in response to a scan command from the tester controller 74, outputs a switching signal to the changeover switch 80, and calculates from the measured voltage value (or voltage value and current value). The resistance value) is compared with a reference voltage value (or reference resistance value) to determine whether the wiring pattern is good or bad. The changeover switch 80 includes a switch array or the like that connects predetermined pins to the constant current source 8 or the voltage detection unit 9 in response to a changeover signal from the inspection processing unit 82.

  The operation of the substrate inspection will be described. The board 16 to be inspected is carried into the carry-in section 54 from the open / close door 52, is placed on the carrying table 60, and is carried and fixed between the upper and lower two inspection jigs 58u and 58d. The inspection jigs 58u and 58d are positioned at the inspectable positions by the inspection jig driving mechanisms 56u and 56d, and the pins of the contact 10 are brought into contact with the corresponding inspection points 18 on the wiring pattern of the substrate 16 to be inspected. .

  Substrate inspection is executed by the control unit 76, tester controller 74, scanner 72, etc., according to the inspection program. When the substrate inspection is completed, the inspection jigs 58 u and 58 d are separated from the substrate 16 to be inspected, sent to the transport unit 54 by the transport table 60, and taken out from the open / close door 52. As described above, normal substrate inspection is performed.

  As described with reference to FIG. 6, the inter-pin short detection inspection and the confirmation inspection after the cleaning operation are performed during the normal substrate inspection. This inspection is performed in the same manner as a normal substrate inspection in the absence of a substrate to be inspected according to an inspection program for the presence or absence of electrical shorts between pins.

  Specifically, an electrical short detection program between pins according to the present embodiment stored in a storage device (not shown) in advance (an inspection program for executing the first method and / or the second method) ), The control unit 76 issues a test start command to the tester controller 74. The tester controller 74 outputs a scan command to the scanner 72 according to an electrical short detection program between pins. The inspection processing unit 82 of the scanner 72 receives a scan command and outputs a switching signal to the changeover switch 80.

  Specifically, in the case of the first method, as shown in FIG. 4A, in the first inspection sequence, the pins in the same pin group can be inspected for continuity between the 4096 pin group and the 4096 pin group. Are connected in parallel and the inspection is performed between the pin groups. In the second inspection sequence, continuity inspection between the 2048 pin group and the 2048 pin group is simultaneously performed at two locations. In the third inspection sequence, continuity inspection between the 1024 pin group and the 1024 pin group is simultaneously performed at four locations. Hereinafter, the process proceeds as shown in FIG. 4A.

  In the case of the second method, as shown in FIG. 4B, in the first inspection sequence, continuity inspection between 1 pin and 1 pin is simultaneously performed at 4096 locations. In the second inspection sequence, the pins in the same pin group are connected in parallel and the inspection between the pin groups is performed simultaneously so that the continuity inspection between the 2-pin group and the 2-pin group can be performed at 2048 locations. In the third inspection sequence, continuity inspection between the 4-pin group and the 4-pin group is simultaneously performed at 1024 locations. Hereinafter, the process proceeds as shown in FIG. 4B.

  The inspection processing unit 82 compares the voltage value when the constant current is passed with the reference voltage value, and determines the presence or absence of an electrical short between the pins. When a short circuit is detected, it is immediately displayed on the operation panel 78 and the inspection is interrupted, and the operator's instructions are followed. If no short is detected, a message to that effect is displayed on the operation panel 78.

  In the short inspection method between pins according to the present invention, all pins to be inspected are divided into two groups, one electrode (for example, positive electrode) is applied to one group, and the other group is applied to the other group. An electrode (for example, a negative electrode) is applied. In this way, by applying each electrode to each group, the continuity between the two groups is measured, and the electrical characteristics (for example, resistance value and current value) between the groups are measured and calculated. Detect shorts between each other.

  Next, when a short circuit between pins is not detected, one group is further divided into two groups, each electrode is applied between these two groups to detect a short circuit, and the other group also has two groups. Dividing into two groups, each electrode is applied between these two groups to detect a short circuit. By repeating this division, the presence or absence of a short between pins is detected.

[Advantages and effects of this embodiment]
The present embodiment has the following advantages and effects.
(1) Compared with the current method, in the method according to the present embodiment, the presence or absence of an electrical short occurring between pins can be inspected in a short time.
(2) Both the first method and the second method can be applied to an arbitrary number of pins.
(3) The second method can be expected to detect the occurrence of an electrical short in a shorter time than the first method in consideration of the positional relationship of the pins.

[Alternative examples and others]
The embodiment described above is an exemplification, and the present invention is not limited to this. Additions, deletions, modifications, improvements, and the like to the embodiments that can be easily made by those skilled in the art are within the scope of the present invention. For example, there are the following alternative examples.

  (1) In the above embodiment, the first and second methods have been described in terms of checking for the presence of electrical shorts between pins. However, the first and second methods can also be employed in normal substrate inspection, that is, substrate continuity inspection, substrate short-circuit inspection, and substrate insulation inspection for a wiring pattern.

  (2) In the above embodiment, the electrical short generated between the pins has been described as being due to the adhesion of solder, but is not limited thereto. The present invention can be applied to all electrical shorts between pins due to adhesion of other conductive materials, deformation of pins, defective inspection jigs, and the like.

  (3) When the first method is described with reference to FIGS. 4A and 5A to 5D, both pin groups to be inspected are groups of the same number of pins. For example, the first inspection order is inspected between the 4096 pin group and the 4096 pin group, and the second inspection order is inspected between the 2048 pin group and the 2048 pin group.

  However, the number of pins in the pin group to be inspected need not be the same. For example, in the inspection sequence shown in FIG. 4A, the total number of pins of 8192 pins is divided into the 4916 pin group and the 3276 pin group at the first time so as to be divided into groups of approximately 0.6: 0.4. The group can be divided into a 2950 pin group and a 1966 pin group, and the next group can be divided into a 1966 pin group and a 1310 pin group for inspection and inspection. If an odd number of pins occur and group division is not possible, add a fictitious pin (empty pin) on the inspection program and adjust it to an even number, and execute the inspection while dividing the group to the end. I can do it.

  Similarly, in the second method described with reference to FIG. 4B, not all pins that have been found to be short-circuited by the inspection are necessarily collected, but a group of pins to be inspected by leaving some pins as they are. A method may be employed in which the number of pins is not the same.

  Accordingly, the technical scope of the present invention is defined by the description of the appended claims.

FIG. 1 is a diagram for explaining a four-terminal method in substrate inspection. FIG. 2 is a diagram showing a state in which a current probe and a voltage probe are combined in order to inspect a substrate having a high-density wiring pattern by a four-terminal method, and as pins arranged in parallel as shown in FIG. Or a pin having a core as shown in FIG. 2B and an annular pin surrounding the pin. FIG. 3 is a diagram for explaining a method of 100% inspection between pins currently being performed. FIG. 4A is a table for explaining a first method of 100% inspection between pins proposed by the present inventors. FIG. 4B is a table for explaining a second method of 100% inspection between pins proposed by the present inventors. FIG. 5A is a diagram for explaining the first inspection sequence of the first method described in FIG. 4A. FIG. 5B is a diagram for explaining the second inspection order of the first method described in FIG. 4A. FIG. 5C is a diagram for explaining a third inspection sequence of the first method described in FIG. 4A. FIG. 5D is a diagram for explaining a fourth inspection order of the first method described in FIG. 4A. FIG. 6 is a flow for performing a short-circuit detection inspection and a confirmation inspection between pins between the substrate inspection and the substrate inspection. FIG. 7 is a side sectional view of the entire substrate inspection apparatus. FIG. 8 is an explanatory diagram of the electrical configuration of the substrate inspection apparatus. FIG. 9 is an explanatory diagram of the configuration of the scanner of the substrate inspection apparatus.

Explanation of symbols

  1a to 1p to 2a to 8p: pins, 2: conductor pattern to be inspected, conductor pattern, 4,4-1, 4-2: current probe, 6,6-1, 6-2: voltage probe, 8: constant current 9: Voltage detection unit: 10, 10-1, 10-2: Contact, 12-1, 12-2, 12-3, 12-4: Pin, 16: Substrate, substrate to be inspected, 18: Inspection Point, Land, 20: Solder bump, 50: Board inspection device, 52: Opening / closing door, 54: Transport section, 56u, 56d: Inspection jig driving mechanism, 58u, 58d: Inspection jig, 60: Transfer table, 72: Scanner 76: Control unit 74: Tester controller 80: Changeover switch 82: Inspection processing unit

Claims (10)

In a substrate inspection apparatus that has a plurality of pins (contact terminals) that are in contact with a predetermined inspection point of a wiring pattern on a substrate and transmit an inspection signal, and inspect the electrical characteristics of the wiring pattern through the pins And means for inspecting the presence or absence of an electrical short between the pins with the substrate removed, the means comprising:
Means for dividing the plurality of pins into two to form a pin group, and further dividing each formed pin group into two to form a pin group until it is divided into one pin;
And means for inspecting the presence or absence of electrical shorts between the divided pin groups or between the pins every time it is divided into two, and after the second division, between the divided pin groups or between the pins A substrate inspection apparatus characterized by simultaneously performing the inspections. In a substrate inspection apparatus that has a plurality of pins (contact terminals) that are in contact with a predetermined inspection point of a wiring pattern on a substrate and transmit an inspection signal, and inspect the electrical characteristics of the wiring pattern through the pins ,
A means for inspecting the presence or absence of electrical shorts between pins or between groups of pins with the substrate removed, and the presence or absence of electrical shorts between pins for all the plurality of pins. At the same time, the pins that are not electrically short-circuited are grouped into one pin group, the presence or absence of an electrical short between these pin groups is simultaneously inspected, and the pin group that is not electrically short-circuited is 1 A board characterized in that it is inspected until all of the plurality of pins are divided into two groups by repeatedly inspecting for the presence or absence of electrical shorts between these pin groups, collectively in one pin group. Inspection device. In the board | substrate inspection apparatus of Claim 1 or 2,
When the actual number of pins of the plurality of pins is not a multiple of 2, the difference between the total number of temporary pins and the actual total number of pins is a multiple of 2 that is larger than the actual total number of pins and the smallest number is the total number of temporary pins. Is defined as a vacant pin, inspects for the presence of electrical shorts between pin groups or between pins, and the inspection between vacant pins and other pins or between vacant pins is treated as having no electrical shorts. . In the board | substrate inspection apparatus of Claim 1 or 2,
The substrate is inspected for the presence or absence of an electrical short between the pin groups or between the pins, after the normal substrate inspection for the substrate is completed and before the start of the normal substrate inspection for the next substrate. Inspection device. The substrate inspection apparatus according to claim 2,
A board that performs a test on a pin with a close pin number at an early stage by assigning a close pin number to a pin that is close in position to the plurality of pins when fixed by an inspection jig. Inspection device. Check for electrical shorts between pins for multiple pins (contact terminals) that are in contact with a predetermined inspection point on the wiring pattern and transmit inspection signals when inspecting the board for electrical characteristics. In the inspection method,
(a) removing the substrate from the pin;
(b) dividing the plurality of pins into two to form a group of pins that are a group of electrically connected pins;
(c) Check for electrical shorts between the pins,
(d) Furthermore, each pin group is divided into two to form electrically connected pin groups,
(e) Inspect simultaneously for the presence of electrical shorts between the divided pin groups,
(f) A test method in which the steps (d) to (e) are repeated until the test between one pin. Check for electrical shorts between pins for multiple pins (contact terminals) that are in contact with a predetermined inspection point on the wiring pattern and transmit inspection signals when inspecting the board for electrical characteristics. In the inspection method,
(a) removing the substrate from the pin;
(b) For all the plurality of pins, simultaneously inspect for the presence of electrical shorts between the pins,
(c) Combine the pins that have no electrical shorts into one pin group, and simultaneously inspect for the presence of electrical shorts between these pin groups,
(d) A group of pins that have no electrical shorts are combined into a single pin group, and the presence or absence of electrical shorts between these pin groups is simultaneously inspected,
(e) A test method in which steps (c) to (d) are repeated until all of the plurality of pins are divided into two groups. In the method for inspecting the presence or absence of an electrical short between pins according to claim 6 or 7,
When the actual number of pins of the plurality of pins is not a multiple of 2, the difference between the total number of temporary pins and the actual total number of pins is a multiple of 2 that is larger than the actual total number of pins and the smallest number is the total number of temporary pins. Is defined as an empty pin, and the presence or absence of an electrical short between pins or between pins is inspected, and the inspection between an empty pin and another pin or between empty pins is treated as no electrical short. . In the method for inspecting the presence or absence of an electrical short between pins according to claim 6 or 7,
The inspection for the presence or absence of an electrical short between the pin groups or between the pins is performed after a normal substrate inspection for a substrate and before a normal substrate inspection for the next substrate is started. how to. The method for inspecting the presence or absence of an electrical short between pins according to claim 7,
For the plurality of pins, an inspection is performed at an early stage by assigning a close pin number to a pin that is close in position when fixed by an inspection jig, and performing an inspection on a pin having a close pin number. how to.

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