WO2014188701A1

WO2014188701A1 - Board inspection method

Info

Publication number: WO2014188701A1
Application number: PCT/JP2014/002631
Authority: WO
Inventors: Munehiro Yamashita
Original assignee: Nidec-Read Corporation
Priority date: 2013-05-20
Filing date: 2014-05-19
Publication date: 2014-11-27
Also published as: JP6182974B2; CN105209924A; KR20150130506A; TWI613451B; TW201627676A; JP2014228301A; CN105209924B; TWI536027B; TW201445145A; KR101663920B1

Abstract

An inspection method that reduces the number of times an inspection is performed on multi-terminal wiring patterns is provided. A board inspection method is a method for inspecting wiring patterns of a sheet board that includes a plurality of unit boards, each having a plurality of multi-terminal wiring patterns, by connecting wiring patterns of at least two of the unit boards to a board inspection apparatus for performing electrical inspection, to determine quality of the wiring patterns. The method includes selecting one wiring pattern that is formed on one unit board and is targeted for inspection and another wiring pattern that is formed on another unit board in the same manner as the one wiring pattern, electrically connecting an arbitrary terminal of the one wiring pattern and an arbitrary terminal of the other wiring pattern to establish a short circuit between the one wiring pattern and the other wiring pattern, and performing an inspection for continuity between a terminal other than the arbitrary terminal of the one wiring pattern and a terminal other than the arbitrary terminal of the other wiring pattern.

Description

BOARD INSPECTION METHOD

The present invention relates to a board inspection method, which is a method for inspecting a board, and more particularly to a board inspection method that improves inspection tact time in the case of inspecting multiple IC package boards included in a single board.

Conventionally, wiring that is formed on a board is used to transmit and receive electrical signals to and from an IC or semiconductor component placed on the board, or other electronic components. Along with recent miniaturization of electronic components, such wiring to be formed is becoming more miniaturized and complicated and getting to have lower resistance. One example of such a board is an IC package board. The IC package board is used to provide electrical connection or fixation between an IC chip and a printed wiring board and to protect the IC chip from outside dirt or dust or outside humidity.

As described above, since the IC package board serves as an interposer that connects an IC chip and a printed wiring board, a fine wiring technique compatible with IC chips is required for the IC package board. Accordingly, extremely fine wiring is formed on the IC package board.

For such an IC package board, in order to assure that each wiring can accurately transmit electrical signals, inspection points that are preset in the wiring are used to measure electrical characteristics such as a resistance value and leakage current between predetermined inspection points and to thereby determine the quality of the wiring on the basis of the measurement result.

Meanwhile, such IC package boards are manufactured in great quantities, and a large number of IC package boards are formed in a single sheet in the manufacturing process. In view of this, there is a technique in which a plurality of inspection jigs are provided in correspondence with inspection points of a plurality of unit boards to be inspected, so that a plurality of unit boards in the sheet board are inspected at once (see PTL(Patent literature) 1, for example).

With PTL 1, an injection jig constituted by a combination of a plurality of inspection jig heads that correspond respectively to unit boards is formed for a sheet board that has a plurality of unit boards arranged in a plurality of rows and columns, and this inspection jig is used for inspection. This allows a plurality of unit boards to be inspected at once, thus improving the efficiency of the inspection.

In the case of using the board inspection jig disclosed in PTL 1, electrical inspection itself is performed for each unit board because the inspection jig heads are merely provided in one-to-one correspondence with the unit boards. In particular, in the case of wiring that includes multiple terminals called voltage/ground (VG) nets (or in other words, for example, power supply layers) that are used to supply a power supply voltage or a ground or used as a shield, continuity inspection needs to be performed for all combinations of two terminals. Thus, even if the inspection jig is provided with a plurality of inspection jig heads, electrical inspection has to be performed for each unit board and the inspection time is not reduced.

[PTL 1] JP 8-21867A

Problem to be Solved by Invention

The present invention has been achieved in light of the above-described circumstances, and provides inspection jig heads that correspond to unit boards in the case of inspecting a sheet board that includes a plurality of unit boards.

Means for Solving Problems

A first aspect of the present invention is a board inspection method for inspecting wiring patterns of a sheet board that includes a plurality of unit boards, each having a plurality of multi-terminal wiring patterns, by connecting wiring patterns of at least two of the unit boards to a board inspection apparatus for performing electrical inspection, to determine quality of the wiring patterns. The method includes selecting one wiring pattern that is formed on one unit board and is targeted for inspection and another wiring pattern that is formed on another unit board in the same manner as the one wiring pattern, electrically connecting an arbitrary terminal of the one wiring pattern and an arbitrary terminal of the other wiring pattern to establish a short circuit between the one wiring pattern and the other wiring pattern, and performing an inspection for continuity between a terminal other than the arbitrary terminal of the one wiring pattern and a terminal other than the arbitrary terminal of the other wiring pattern. According to a second aspect of the present invention, a short-circuiting terminal that establishes a short circuit between the one wiring pattern and the other wiring pattern is provided at a board inspection jig that electrically connects the board inspection apparatus and the sheet board. According to a third aspect of the present invention, a short-circuiting terminal that establishes a short circuit between the one wiring pattern and the other wiring pattern is provided at a connection that electrically connects the board inspection apparatus and a board inspection jig that electrically connects the board inspection apparatus and the sheet board. According to a fourth aspect of the present invention, the inspection for continuity between a terminal other than the arbitrary terminal of the one wiring pattern and a terminal other than the arbitrary terminal of the other wiring pattern continues until all combinations of connections between the one wiring pattern and the other wiring patterns have been inspected.

Advantageous Effects of the Invention

With the first aspect of the present invention, the number of times an inspection is performed can be reduced because an arbitrary terminal of the one wiring pattern and an arbitrary terminal of the other wiring pattern are electrically connected to each other in order to establish a short circuit between the one wiring pattern and the other wiring pattern, and continuity between a terminal other than the arbitrary terminal of the one wiring pattern and a terminal other than the arbitrary terminal of the other wiring pattern is inspected for. In particular, as compared to the conventional inspection method, the number of times an inspection is performed can be reduced to about a half, and accordingly the inspection tact time can be extremely reduced. According to the second aspect of the present invention, since the short-circuiting terminal that establishes a short circuit between the one wiring pattern and the other wiring pattern is provided at the board inspection jig that electrically connects the board inspection apparatus and the sheet board, it is possible to implement the present invention by manufacturing the board inspection jig. Accordingly, the inspection method of the present invention can be implemented at low cost. According to the third aspect of the present invention, since the short-circuiting terminal that establishes a short circuit between the one wiring pattern and the other wiring pattern is provided at the connection that electrically connects the board inspection apparatus and the board inspection jig that electrically connects the board inspection apparatus and the sheet board, it is possible to implement the board inspection in a simple and easy manner by providing a short-circuited portion at the connection of the board inspection apparatus, without the need to configure a complicated apparatus. According to the fourth aspect of the present invention, since the inspection for continuity between a terminal other than the arbitrary terminal of the one wiring pattern and a terminal other than the arbitrary terminal of the other wiring pattern continues until all combinations of connections between the one wiring pattern and the other wiring patterns have been inspected, the continuity between the one wiring pattern and the other wiring pattern can be inspected reliably and in a shorter inspection time.

[FIG. 1] FIG. 1 is a plan view showing an embodiment of a sheet board.
[FIG. 2] FIG. 2 is a schematic cross-sectional view of a unit board having wiring patterns to be inspected according to the present invention.
[FIG. 3] FIG. 3 is a cross-sectional view of the schematic side view of a board inspection apparatus according to the present invention.
[FIG. 4] FIG. 4 is a schematic side view of a board inspection jig according to the present invention.
[FIG. 5] FIG. 5 is a schematic view of an embodiment of the present invention, schematically illustrating how four unit boards are inspected.
[FIG. 6] FIG. 6 schematically illustrates an inspection method according to the present invention.

A preferred embodiment for carrying out the present invention will now be described. It is an object of the present invention to efficiently perform an inspection of a sheet board B that includes a plurality of unit boards CB each having at least one multi-terminal wiring pattern P. First, the sheet board B to be inspected will be described. FIG. 1 illustrates an embodiment of the sheet board B. The sheet board B shown in FIG. 1 is formed as a sheet in which a plurality of unit boards CB each having a plurality of wiring patterns are formed in a matrix. As shown in FIG. 1, this board B is formed by arranging a plurality of unit boards CB to be inspected in a matrix of a plurality of rows and columns. The board B will be divided into individual unit boards CB after inspection processing or the like has been performed. Each of the unit boards CB has a plurality of wiring patterns that are the same as those of the other unit boards CB. The board B shown in FIG. 1 is constituted by five rows and fifteen columns of unit boards CB. The numbers of rows and columns of unit boards CB is not particularly limited. For convenience of description, it is assumed in the specification and drawings of the present invention that the column direction of the board B is the x direction, the row direction orthogonal to the column direction is defined as the y direction, and the direction perpendicular (normal) to the plane of the board B is defined as the z direction.

The unit boards CB each have wiring patterns made of a metal such as copper, and continuity/short-circuit inspections of these wiring patterns are performed. These wiring patterns have preset inspection points that are to be brought into conducting contact with contacts, which will be described later. Note that in the specification of the present invention, these inspection points are assumed to be end points of wiring patterns P. The inspection points are normally set such that they are brought into contact with the contacts so as to transmit and receive electrical signals to and from a board inspection apparatus.

Next, multi-terminal wiring patterns will be described. A cross-sectional view of a unit board CB in FIG. 2 shows three wiring patterns P (P1 to P3). The wiring patterns P1 and P2 are each wiring that is called a signal net (so-called a "signal line") for transmitting signals and that has one end at a front surface CB1 of the unit board CB and the other end at a rear surface CB2. This allows electrical connection to be established between the front surface CB1 and rear surface CB2 of the unit board CB. Note that a signal net that is provided to connect two land portions to enable transmission and reception of electrical signals often has a relatively simple wiring path and, accordingly, often has a relatively short total path length and a relatively small surface area, for example.

The wiring pattern P3 is wiring called a voltage/ground (VG) net (or in other words, for example, a power supply layer) that is used to supply a power supply voltage or a ground or used as a shield. In the example of FIG. 2, the wiring pattern P3 is illustrated as having four end points at the front surface CB1 of the unit board CB and four end points at the rear surface CB2. This VG net (wiring pattern P3) has to supply a power supply voltage or a ground to a plurality of locations in the unit board CB and sometimes also serves as a shield against signal nets. The VG net is thus often formed in a mesh pattern in the unit board CB and, accordingly, often has a relatively long total path length and a relatively large surface area, for example.

It is an object of the present invention to efficiently inspect a multi-terminal wiring pattern P such as the wiring pattern P3 formed on a unit board CB of the sheet board B. The sheet board B includes a plurality of unit boards CB each having a plurality of wiring patterns P. The wiring patterns P include both signal nets and VG nets. Note that because the present invention is suitable for the case of inspecting a multi-terminal wiring pattern, explanations of a signal net (two-terminal wiring pattern), such as the wiring patterns P1 and P2, that connects predetermined two points will basically be omitted in the following description.

Next is a description of a board inspection apparatus 1 for inspecting a board, used in the present invention. FIG. 3 is a cross-sectional view showing the structure of the board inspection apparatus 1 according to an embodiment of the invention. From the viewpoint of clarifying the directions of movement of a conveying table 20 and first and second inspection

jig moving units

30 and 40, an orthogonal coordinate system represented by X, Y, and Z axes is illustrated in FIG. 3. The Y axis is set such that its positive direction is a direction from the front side of the drawing of FIG. 3 to the rear side thereof.

The board inspection apparatus 1 includes a board moving unit 60 that moves the conveying table 20 along the X axis, and the first and second inspection

jig moving units

30 and 40 that respectively move, in the YZ plane, inspection jigs 32 and 42 to which a plurality of probe pins 35 and 45 for use in board inspection are attached. The first and second inspection

jig moving units

30 and 40 are arranged symmetrically with respect to the XY plane.

The conveying table 20 includes a board holding unit 22 on which a board to be inspected (inspection board) 21 is placed, and a cylindrical bracket 63 that is fixed to the underside of the board holding unit 22. The cylindrical bracket 63 has a screw hole penetrating therethrough in the longitudinal direction.

The board moving unit 60 includes a ball screw 62 that is to be engaged with the screw hole of the bracket 63, and a driving unit 61 that rotates the ball screw 62. To simplify the illustration, screw threads and grooves of the ball screw 62 are not shown. When the ball screw 62 is rotated by the driving unit 61, the amount and direction of the rotation determine the amount and direction of movement of the bracket 63, i.e., the conveying table 20 in a direction along the X axis.

The first inspection jig moving unit 30 includes an inspection jig holding unit 33. The inspection jig holding unit 33 functions to hold the inspection jig 32 to which the probe pins 35 for use in board inspection are attached and to move the inspection jig 32 so that the probe pins 35 for use in board inspection are brought into contact with inspection points of wiring to be inspected on an inspection board 21. The probe pins 35 for use in board inspection or the like are also electrically connected to a scanner (not shown) for inspecting and measuring a board via the inspection jig holding unit 33.

The second inspection jig moving unit 40 includes an inspection jig holding unit 43 that is similar to the inspection jig holding unit 33 of the first inspection jig moving unit 30. The inspection jig holding unit 43 functions in the same manner as the inspection jig holding unit 33 does.

The movement of the first and second inspection

jig moving units

30 and 40 and the board moving unit 60 is controlled by a control device (not shown) of the board inspection apparatus 1. The first and second inspection

jig moving units

30 and 40 also respectively have main cameras 34 and 44 attached thereto to specify the positions of the inspection board 21 and the conveying table 20.

Next, the inspection jig 32 (or 42) used in the board inspection apparatus 1 will be described. FIG. 4 illustrates an embodiment of the inspection jig. The inspection jig 32 is constituted by a plurality of contacts 35 (45), a supporter 3 that supports these multiple needle-like contacts, an electrode body 4 that supports the supporter 3 and includes electrode portions that are brought into contact with the contacts 35 to become conductive with the board inspection apparatus, a conductor 5 that is electrically connected to and extends from the electrode portions, and a connector 6 that includes connections electrically connected to the board inspection apparatus. FIG. 4 is a schematic side view illustrating an overview of the inspection jig 32. While the three contacts 35 are shown in FIG. 4, the number of contacts 35 is not particularly limited.

The contacts 35 electrically connect the inspection points set on the wiring patterns P and the electrode portions, which will be described later. One ends of the contacts 35 are in contact with the inspection points, and the other ends of the contacts 35 are in contact with the electrode portions. That is, the contacts 35 establish electrical connection between the inspection points and the electrode portions. The contacts 35 may, for example, be formed of a member that is of an elongated rodlike shape and has conductivity and flexibility. Alternatively, the contacts 35 may be formed of a member using a spring that extends and contracts in the longitudinal direction.

The electrode body 4 holds the electrode portions (not shown) that are in contact with the other ends of the contacts 35 and electrically connected to the board inspection apparatus. The electrode portions are formed so as to be substantially flush with the surface of the electrode body 4. The electrode portions are preferably slightly larger than the outer diameter of the contacts 35.

The conductor 5 electrically connects the electrode portions of the electrode body 4 and connections 61 of the connector 6, which will be described later. The conductor 5 needs only to be capable of establishing electrical connection between the electrode portions 41 and the connections 61, and it may, for example, be formed of linear metal wires such as copper wires.

In the case of forming the conductor 5 of metal wires, the electrode portions can be formed by forming through holes in the electrode body 4, disposing conductor wires in the through holes, and cutting the conductor wires so that they are flush with the surface of the electrode body 4. In this case, one ends of the metal wires function as the electrode portions, and the other ends of the metal wires are conductively connected to the connections 61.

The connector 6 holds the connections 61 that are electrically connected to the board inspection apparatus. The connections 61 are electrically connected to the board inspection apparatus 1 by being brought into conducting contact with connection points provided in the board inspection apparatus 1. This connection may, for example, be connection via connectors formed in uneven shapes.

The supporter 3 holds the contacts 35 and guides one ends of the contacts 35 to the inspection points and the other ends of the contacts 35 to the electrode portions. The supporter 3 shown in FIG. 4 is formed by two plate-like members that are disposed at a predetermined interval, and the contacts 35 can be bent in the space formed by these two plate-like members.

The board inspection jig 32 (42) is configured to include at least two inspection jig heads (not shown) that correspond respectively to unit boards CB. The inspection jig heads are disposed such that the contacts 35 (45) are in contact with the inspection points preset on the wiring patterns P of the unit boards CB. Thus, the inspection jig heads are in one-to-one correspondence with the unit boards CB. The board inspection jig 32 that includes four inspection jig heads can inspect four unit boards CB of the sheet board B with a single press. That is, the number of unit boards CB that can be inspected with a single press can be set according to the number of inspection jig heads.

Although described in detail later, it is preferable in the present invention to provide an even number of inspection jig heads because inspections are performed by establishing a short circuit between one wiring pattern formed in one unit board CB and the same wiring pattern formed in another unit board CB different from the one unit board CB. By providing an even number of inspection jig heads, it is possible to reduce the inspection time with efficient use of the inspection jig heads.

To implement the present invention, one wiring pattern P formed in one unit board CB and another wiring pattern that is the same as the wiring pattern P and is formed in another unit board CB are short-circuited. This is equivalent to establishing electrical connection between an arbitrary terminal of the one wiring pattern P of the one unit board CB and an arbitrary terminal of the other wiring pattern P of the other unit board CB. In other words, the one wiring pattern P and the other wiring pattern P are connected in series to provide series-connection between predetermined patterns of the one unit board CB and the other unit board CB.

As another example, a short-circuiting terminal SW may be a connection (not shown) that provides electrical connection between the board inspection apparatus 1 and the board inspection jig 32 that electrically connects the board inspection apparatus 1 and the sheet board B. In the case of using such a connection, settings are made such that one end of one wiring pattern P and one end of another wiring pattern P can be electrically connected at this connection. As with the case described above, it is preferable for the short-circuiting terminal SW to have a switching function that enables ON/OFF switching of short-circuit conditions.

Although the relative positions of one wiring pattern P and another wiring pattern P are not particularly limited, it is preferable to use adjacent unit boards CB. Use of the wiring patterns P of adjacent unit boards CB allows efficient use of unit boards CB.

Arbitrary terminals that connect one wiring pattern P and another wiring pattern P are not particularly limited as long as it can establish series-connection between the one wiring pattern P and the other wiring pattern P. The short-circuiting terminal that provides series-connection between these wiring patterns P may be provided in the board inspection jig 32(42) that electrically connects the board inspection apparatus 1 and the sheet board B. More specifically, the conductor 5 of the board inspection jig 32 shown in FIG. 4 can be used. In this case, it is possible to adopt a method of providing a short-circuiting terminal SW that establishes a short circuit between a conductor 5 that is electrically connected to one end of one wiring pattern P and a conductor 5 that is electrically connected to one end of another wiring pattern P that is series-connected to the one end of the one wiring pattern P. The short-circuiting terminal SW may be a switching element, and settings are preferably made such that an operator who performs inspections is capable of switching on and off of short-circuit conditions.

FIG. 5 is a diagram for explaining the case of using short-circuiting terminals SW1 and SW2. In the example of FIG. 5, four unit boards CB (unit boards CB(A) to CB(D)) are formed on a sheet board B, and the unit boards respectively have patterns P (wiring patterns P(1) to P(4)). The wiring pattern P has five terminals 1 to 5. Note that each of the terminals has a group of contacts 30 disposed for electrical connection with the board inspection apparatus 1. Note that only the so-called multiple-terminal wiring patterns P on the unit boards CB are illustrated, and the wiring patterns P (P(1) to P(4)) of all of the unit boards CB are the same wiring pattern P.

In the example of FIG. 5, the terminal 5 of the wiring pattern P(1) of the unit board CB(A) and the terminal 1 of the wiring pattern P(2) of the unit board CB(B) are conductively connected via the short-circuiting terminal SW1. Also, the terminal 5 of the wiring pattern P(3) of the unit board CB(C) and the terminal 1 of the wiring pattern P(4) of the unit board CB(D) are conductively connected via the short-circuiting terminal SW2. Note that the short-circuiting terminals SW1 and SW2 are each a switch that can be turned on and off.

The board inspection apparatus 1 includes a group of switches, a power supply, a voltmeter, and an ammeter, all of which are not shown, and is capable of measuring a board to be inspected through on-off control action of the group of switches. For example, in the case of determining the quality of wiring resistance between the

terminals

1 and 2 of the wiring pattern P(1), a predetermined potential is applied between the

terminals

1 and 2 to measure the current flowing between the

terminals

1 and 2. Then, a difference in potential (voltage value) and the current value in this case are used to calculate the resistance value, and the quality of wiring is determined on the basis of the resistance value. The above has been a description of the board inspection apparatus 1, the board inspection jig 32, and the short-circuiting switch SW, which are used to implement the present invention.

Next, an inspection method according to the present invention will be described with reference to Figs. 5 and 6. The present invention enables efficient inspection of the wiring patterns P formed on the unit boards CB. In the case of Figs. 5 and 6, the short-circuiting terminal SW1 is first turned on.

Next, the terminal 4 of the wiring pattern P(1) and the terminal 2 of the wiring pattern P(2) form a closed circuit via the short-circuiting terminal SW1, and the resistance value between these

terminals

4 and 2 is calculated to determine the quality of the wiring. Next, the terminal 3 of the wiring pattern P(1) and the terminal 3 of the wiring pattern P(2) form a closed circuit via the short-circuiting terminal SW1, and the resistance value between the terminal 3 of the wiring pattern P(1) and the terminal 3 of the wiring pattern P(2) is calculated to determine the quality of the wiring. Next, the terminal 2 of the wiring pattern P(1) and the terminal 4 of the wiring pattern P(2) form a closed circuit via the short-circuiting terminal SW1, and the resistance value between the terminal 2 of the wiring pattern P(1) and the terminal 4 of the wiring pattern P(2) is calculated to determine the quality of the wiring. Then, the terminal 1 of the wiring pattern P(1) and the terminal 5 of the wiring pattern P(2) form a closed circuit via the short-circuiting terminal SW1, and the resistance value between the terminal 1 of the wiring pattern P(1) and the terminal 5 of the wiring pattern P(2) is calculated to determine the quality of the wiring. In this way, the wiring pattern P(1) and the wiring pattern P(2) are conductively connected to each other via the short-circuiting terminal SW1, which reduces the number of times an inspection is performed from the conventional number of times, i.e., eight, to four.

Although a detailed description has been omitted, similar processing is also performed on the wiring patterns P (wiring patterns P(3) and P(4)) of the unit board CB(C) and CB(D). Accordingly, the number of times an inspection is performed can be reduced to a half of that in the conventional case, in the case of inspecting the wiring patterns P.

Industrial Availability

While the specification of the present invention takes the example of the case in which the board to be inspected is an IC package board, the board to be inspected may be various types of boards such as a printed circuit board, a flexible printed circuit board, a ceramic multilayer wiring board, an electrode board for liquid crystal display or plasma display, and a package board or film carrier for semiconductor packaging, or it may be a semiconductor device such as a semiconductor wafer, a semiconductor chip, or a chip size package (CSP).

1 Board inspection apparatus
32 Board inspection jig
B Sheet board
CB Unit board
SW Short-circuiting terminal

Claims

A board inspection method for inspecting wiring patterns of a sheet board that includes a plurality of unit boards, each having a plurality of multi-terminal wiring patterns, by connecting wiring patterns of at least two of the unit boards to a board inspection apparatus for performing electrical inspection, to determine quality of the wiring patterns, the method comprising:
selecting one wiring pattern that is formed on one unit board and is targeted for inspection and another wiring pattern that is formed on another unit board in the same manner as the one wiring pattern;
electrically connecting an arbitrary terminal of the one wiring pattern and an arbitrary terminal of the other wiring pattern to establish a short circuit between the one wiring pattern and the other wiring pattern; and
performing an inspection for continuity between a terminal other than the arbitrary terminal of the one wiring pattern and a terminal other than the arbitrary terminal of the other wiring pattern.
The board inspection method according to claim 1, wherein
a short-circuiting terminal that establishes a short circuit between the one wiring pattern and the other wiring pattern is provided at a board inspection jig that electrically connects the board inspection apparatus and the sheet board.
The board inspection method according to claim 1, wherein
a short-circuiting terminal that establishes a short circuit between the one wiring pattern and the other wiring pattern is provided at a connection that electrically connects the board inspection apparatus and a board inspection jig that electrically connects the board inspection apparatus and the sheet board.
The board inspection method according to any one of claims 1 to 3, wherein
the inspection for continuity between a terminal other than the arbitrary terminal of the one wiring pattern and a terminal other than the arbitrary terminal of the other wiring pattern continues until all combinations of connections between the one wiring pattern and the other wiring patterns have been inspected.