JPH10206485A - Substrate inspecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate inspecting apparatus which can correctly set a tip pitch of a pin probe even if there is an error in a substrate thickness. SOLUTION: The substrate inspecting apparatus 1 including a probe unit for holding a plurality of pin probes arranged in a sector so that they can protrude from a unit body 3, wherein the probe unit 4 is separated by a predetermined distance from a substrate 10 to be inspected and at least two of the plurality of pin probes 2, 2... are made to protrude from the unit body 3, whereby tips of the respective protruding pin probes 2, 2... are brought in contact with a substrate face and pitches among the tips are set in a length according to a predetermined distance for inspecting the substrate 10. In this case, it includes distance measuring means 11, 31 for measuring from a predetermined reference position to the surface of the substrate 10 and a position correction means 31 for correcting a position of the probe unit 4 according to the distance measured by the distance measuring means 11, 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board
C package, hybrid substrate and MCM (Mult
i. A board inspection device that inspects the circuit pattern of a circuit board such as an iChip Module) and the quality of mounted circuit components.For details, a plurality of pin probes arranged in a fan shape protrude from the unit body to form a circuit pattern. The present invention relates to a board inspection apparatus for inspecting a board in a state where the board is in contact with the board.

[0002]

2. Description of the Related Art The applicant has already developed an XY in-circuit tester employing a probe unit constituted by arranging a plurality of pin probes in a fan shape. As shown in the conceptual diagram of FIG. 7, the XY in-circuit tester includes, for example, thirteen pin probes 2, 2,.
The probe units 4 are arranged in a fan shape so that they can protrude from the unit. By selecting a required number from these pin probes 2, 2,. In a state where 2... Are in contact with the substrate 10 to be inspected, it is possible to inspect a multi-pin component such as an integrated circuit.

As a specific configuration of the probe unit 4, for example, as shown in FIG. 6, an air cylinder 14 formed corresponding to each pin probe 2 includes a unit body 3.
In the air cylinder 14, a compression coil spring 15 wound around the pin probe 2 is housed. The pin probe 2 has a distal end retracted in a direction indicated by an arrow shown in FIG. 4 by the spring force of the compression coil spring 15 at normal times. When compressed air is supplied from the air supply port 16 of the air cylinder 14, the pin probe 2 It is configured to protrude in the opposite direction. The pin probe 2 has
The measurement cables 17 are individually connected, and a board inspection can be performed by outputting an inspection signal through the measurement cable 17 or inputting the inspection signal in reverse.

Next, X using this probe unit 4
The operating principle of the -Y in-circuit tester will be described. In this XY in-circuit tester, for each board 10 to be inspected, the board thickness, the pin probes 2, 2,.
The pitch between circuit patterns to be contacted (eg,
0.4 mm, 0.65 mm, etc.) are stored in advance. For this reason, as shown in FIG. 5, in a state where the substrate 10 is fixed to a substrate fixing table (not shown), the probe unit 4
Are separated from the substrate 10 by a distance corresponding to the substrate thickness and the pitch between circuit patterns, and then the compressed air is supplied to the air supply port 16 so that the pin probes 2, 2,. The contact pitch between the tip ends of the pin probes 2, 2,... In other words, in the XY in-circuit tester, as shown in FIG. 3, when the pitch between circuit patterns is widened, the probe unit 4 is moved closer to the substrate 10 by a distance corresponding to the pitch, so that the tips of the pin probes 2 The pitch between patterns can be adjusted to the pitch between circuit patterns. This makes it possible to probe a plurality of circuit patterns connected to terminals of a plurality of types of integrated circuits or QEPs having different pitches between pins at a time, thereby achieving high-speed inspection.

[0005]

However, the XY in-circuit tester developed by the applicant has room for improvement as described below. That is, in order to adjust the tip pitch of the pin probe 2 to the pitch of the circuit pattern, the substrate 1
It is a precondition that 0 is accurately manufactured to the specified thickness. Therefore, when there is an error in the substrate thickness or when the substrate 10 is locally warped, the tip pitch of the pin probe 2 does not match the pitch of the circuit pattern, so that the pin probe 2 contacts the circuit pattern accurately. May not, and there is room for improvement in this regard.

The present invention has been made in view of such improvements, and provides a substrate inspection apparatus capable of accurately setting the tip pitch of a pin probe even when there is an error in substrate thickness. The main purpose is to

[0007]

According to a first aspect of the present invention, there is provided a substrate inspection apparatus comprising a probe unit for holding a plurality of pin probes arranged in a fan shape so as to protrude from a unit body. Is separated from the substrate to be inspected by a predetermined distance, and at least two of the plurality of pin probes are made to protrude from the unit main body so that the tips of the protruded pin probes are brought into contact with the substrate surface and What is claimed is: 1. A board inspection apparatus for inspecting a board in a state in which an interval pitch is set to a length corresponding to a predetermined distance, comprising: a distance measuring means for measuring a distance from a predetermined reference position to a surface of the substrate; And a position correcting means for correcting the position of the probe unit according to the distance measured by the method.

In this circuit board inspection, for example, the distance measuring means uses, as a reference position, an upper surface of a substrate fixing stand for fixing a substrate to be inspected, or a virtual position above the substrate as a reference position.
The distance from the reference position to the surface of the substrate is measured. Next, when there is an error in the measured distance as compared with the distance when the substrate has the theoretical substrate thickness, the position correcting means corrects the position of the probe unit so as to cancel the error. As a result, even if there is an error in the substrate thickness or the substrate is warped locally, each pin probe can be accurately brought into contact with a circuit pattern having a predetermined pitch on the substrate surface. .

According to a second aspect of the present invention, there is provided a substrate inspection apparatus.
In the above-described substrate inspection apparatus, the distance measuring unit includes a differential displacement sensor and a calculation unit that calculates a distance based on a sensor signal of the differential displacement sensor. .

The distance measuring means may be a laser displacement meter, a CCD,
It may be constituted by image processing means or the like for digitally processing an image picked up by a camera, but it is generally complicated and expensive. In this board inspection device,
Since the calculating section calculates the distance based on the sensor signal of the differential displacement sensor, the distance measuring means can be configured simply and inexpensively.

According to a third aspect of the present invention, there is provided a substrate inspection apparatus comprising: a probe unit for holding a plurality of pin probes arranged in a fan shape so as to protrude from the unit main body; And by projecting at least two of the plurality of pin probes from the unit main body, the tips of the projected pin probes are brought into contact with the substrate surface, and the pitch between the tips is set to a length corresponding to a predetermined distance. A substrate inspection apparatus for inspecting the substrate in a state where the substrate unit has been set, wherein the substrate thickness measurement unit measures the thickness of the substrate, and the position correction unit corrects the position of the probe unit according to the thickness measured by the substrate thickness measurement unit And characterized in that:

In this substrate inspection apparatus, unlike the substrate inspection apparatus according to the first aspect, the substrate thickness measuring means directly measures the substrate thickness. Next, when there is an error in the measured substrate thickness as compared with the theoretical substrate thickness, the position correction means corrects the position of the probe unit so as to cancel the error. As a result, even if there is an error in the substrate thickness or the substrate is warped locally, each pin probe can be accurately brought into contact with a circuit pattern having a predetermined pitch on the substrate surface. .

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

First, the configuration of the board inspection apparatus 1 will be described with reference to FIG.

The board inspection apparatus 1 shown in FIG. 1 is a configuration diagram of an XY type in-circuit tester to which the present invention is applied. The board inspection apparatus 1 includes a probe unit 4 that holds a plurality of pin probes 2, 2,... It should be noted that the probe unit 4 in the XY in-circuit tester that has been already developed by the applicant has the same structure, and therefore, the same reference numerals are given to the respective components, and duplicate description will be omitted.

In the probe unit 4, an arm 5 projecting from the unit body 3 is fixed to an endless belt 7 driven by a motor 6 such as a stepping motor or a servo motor. Therefore, when the motor 6 rotates, the probe unit 4 moves vertically with respect to the substrate 10 to be inspected by the driving force.
Each pin probe 2 of the probe unit 4 is formed of a conductor, and a measurement cable (not shown) connected to the rear end of each pin probe 2 is connected to the connector 8. The connector 8 is connected to a measuring unit 34 described later via the flat cable 9.

The board inspection apparatus 1 further includes a differential transformer type sensor (a control unit 31 described later) for measuring the height of the surface of the board 10 to be inspected, which is installed on a board fixing table (not shown).
Together with the distance measuring means and the substrate thickness measuring means of the present invention) 11, an air cylinder 12 for vertically moving the differential transformer type sensor 11, and an air cylinder 1
2 is provided with an air supply unit 13 for supplying compressed air.

The differential transformer type sensor 11 includes a contact 21 configured to be able to be pushed into the inside of the sensor body when brought into contact with the surface of the substrate 10, and a magnetic core 22 connected to the contact 21. And a primary winding 23 and secondary windings 24a, 24 magnetically coupled to each other by a magnetic core 22.
b.

The differential transformer type sensor 11 is configured so that an AC voltage corresponding to an AC signal supplied to the primary winding 23 is induced in the secondary winding 24a and the secondary winding 24b. Here, the two secondary windings 24a and 24b have the phase of the alternating-current signal induced at both ends thereof of 180 degrees.
° Winded differently. For this reason, the differential transformer type sensor 11
When is not pushed into the sensor body, no AC signal is induced at both ends of the secondary windings 24a and 24b. On the other hand, when the contact 21 is pushed into the sensor main body by the length L _0, an AC signal having a voltage value V ₀ is induced at both ends of the secondary windings 24a and 24b, and the length L ₁ (L ₁ >).
L ₀ ) When pressed, an AC voltage that is substantially proportional to the difference (L ₁ −L ₀ ) is induced. Therefore, in the board inspection apparatus 1, when the board 10 having the theoretical board thickness t stored in advance in the control unit 31 described later is to be inspected, the contact 21 is placed inside the sensor body for a predetermined length L ₀ minutes. as pressed, moves the differential transformer type sensor 11 to the reference position, where the secondary winding 24a, by measuring the AC voltage induced across the 24b, based on the voltage difference with respect to the voltage value V ₀ Thus, it is possible to calculate the thickness error of the substrate 10 with respect to the theoretical substrate thickness t.

The air cylinder 12 has an air supply port 12
a, 12b and a piston 12c. In the air cylinder 12, when compressed air is sent into the air supply port 12a by the air supply unit 13, the differential transformer type sensor 11 is moved toward the substrate 10 by moving the piston 12c downward in FIG. When the compressed air is supplied to the air supply port 12b, the differential transformer type sensor 11 is separated from the substrate 10 by moving the piston 12c upward in FIG.

Further, the board inspection apparatus 1 includes a control section 31 corresponding to a position correcting means, a distance measuring means, a calculating section and a board thickness measuring means in the present invention, an AC signal output section 32, A
A / D conversion unit 33 and a measurement unit 34 are provided. Here, the control unit 31 includes, for example, a CPU and a memory, and controls the air supply operation to the air supply unit 13, the rotation control of the motor 6, and the probe unit 4 based on the sensor signal of the differential transformer type sensor 11. It performs movement amount control and movement amount correction processing. Further, the AC signal output unit 32 outputs an AC signal of a predetermined voltage to the primary winding 23 of the differential transformer type sensor 11 under the control of the control unit 31. A / D converter 3
3 is a secondary winding 24a, 2 of the differential transformer type sensor 11.
It rectifies the AC signal output from 4b and outputs the voltage data _DH generated by analog-to-digital conversion of the rectified DC voltage to the control unit 31. The measuring unit 34 outputs a test signal to the pin probe 2, measures the voltage value of the test signal input via the pin probe 2, and outputs the measured voltage data _DV to the control unit 31.

Next, with reference to FIGS. 2 and 3, the principle of the movement amount correction processing performed by the control unit 31 will be described. As shown in FIG. 2, each pin probe 2, 2,.
When the probe unit 4 is located at a predetermined position above the substrate 10 (hereinafter, this position is referred to as “Z-axis Z ₀ ”), the top of the substrate fixing base 41 for fixing the substrate 10 They coincide at the virtual intersection 51 at the one-plane position.
That is, if the pin probe 2 is protruded while the probe unit 4 is moved to the Z-axis height Z _0, it means that the tips of all the pin probes 2, 2... However, it is not always necessary to make them coincide with each other, and it is only necessary that the extension lines of the tip portions coincide. In this case, the pitch between the pin probes 2 is 0. Here, the height Z ₀ is stored in the internal memory of the control unit 31 in advance.

Next, a description will be given of the control to the across pins probe 2,2 pitch into contact with the surface of the substrate 10 to the value P _1.

As shown in FIG. 3 (a), when the probe unit 4 further length Z lowered to ₁ minute with respect to the Z-axis, as shown in FIG. (B), wherein the following relationship is established .
In this case, the probe unit 4 uses the (Z ₀ +
Z ₁ ). (T + Z ₁ ) = P ₁ × (1 / tan θ ₁ ) where “t” and “θ ₁ ” respectively mean the theoretical value of the substrate thickness and the angle between the pin probes 2 and 2. I do. Therefore, the following equation is established by modifying the equation. Z ₁ = P ₁ × (1 / tan θ ₁ ) -t formula

[0025] Thus, when the pitch between pins probes 2 and 2 in contact with the surface of the substrate 10 to a value P ₁ is
The probe unit 4 may be further lowered from the state of FIG. 2 by the length Z ₁ . Therefore, the position Z on the Z axis of the probe unit 4 in FIG. 3A is expressed by the following equation. Z = Z ₀ + Z ₁ = P ₁ × (1 / tan θ ₁ ) −t + Z ₀ ... Where the value (1 / tan θ ₁ ) is
The above equation is represented by the following equation if the proportionality constant is “k” because it is uniquely determined from the array angle of Z = k × P ₁ −t + Z ₀ formula

Thus, the control unit 31 stores the theoretical substrate thickness t and the proportionality constant k of the substrate 10 as parameters in the internal memory in addition to the height Z ₀ , so that the pin on the surface of the substrate 10 When the pitch _Pn between the probes 2 is specified, the position of the probe unit 4 on the Z axis can be immediately calculated based on these parameters.

On the other hand, if the thickness of the substrate 10 is different from the theoretical substrate thickness t by a thickness error Δt due to a manufacturing error or the like, moving the probe unit 4 in accordance with the above equation causes the thickness error Δt. As a result, the specified pitch between the pin probes 2 is not set accurately. Therefore, the control unit 31 calculates the thickness error Δt with respect to the theoretical substrate thickness t of the substrate 10 based on the voltage data D _H output from the A / D conversion unit 33, and then moves the probe unit 4 as described above. Correct the amount. That is, the fact that the substrate is manufactured to be thicker by the thickness error Δt with respect to the theoretical substrate thickness t means that in FIG. 3A, the relative movement amount with respect to the surface of the substrate 10 is actually the movement amount (Z ₁ + Δt), the amount of movement of the probe unit 4 may be corrected by the correction amount (−Δt). Therefore, the control unit 3
1 moves the probe unit 4 according to the following equation. Z = k × P ₁ −t + Z ₀ −Δt (Equation 2) This is a case where a manufacturing error occurs in the thickness of the substrate 10 or the substrate 10 is warped. However, the pitch between the pin probes 2 and 2 can be accurately set.

Next, with reference to FIGS. 1 and 3, the overall operation of the board inspection apparatus 1, particularly the control of the movement of the probe unit 4 by the control unit 31, will be mainly described.

First, when the substrate 10 is set on the substrate fixing table 41, the control unit 31 controls the air supply unit 13 to set the differential transformer type sensor 11 at the reference position. Then, by outputting an AC signal from the AC signal output section 32 receives the voltage data D _H via the A / D converter 33, on the basis of the voltage difference with respect to the voltage value V ₀ described above, the substrate thickness theory The thickness error of the substrate 10 with respect to t is calculated.

Next, the controller 31 controls the probe unit 4
After reading the pitch between circuit patterns to be inspected from the inspection execution program stored in the internal memory, the movement amount of the probe unit 4 is calculated according to the above equation. Next, the control unit 31 moves the probe unit 4 by driving the motor 6 according to the calculated movement amount. When the probe unit 4 is moved to a predetermined position, the control unit 31 drives an air supply device (not shown) so that predetermined pin probes 2, 2,... Make contact.

Next, the control section 31 causes the measuring section 34 to output an inspection signal from a predetermined pin probe 2 and to output a voltage value of the inspection signal input through another predetermined pin probe 2. Is measured. When the voltage data D _V is output from the measurement unit 34, the control unit 31 based on the voltage data D _V, calculates the resistance value between the circuit patterns,
Based on the calculation result, it is determined whether a defect such as a solder bridge has occurred between the circuit patterns.

As described above, according to the board inspection apparatus 1 of the present embodiment, the thickness error is reduced in the vicinity of the circuit pattern on the board 10 to be brought into contact with the pin probes 2 due to a manufacturing error or warpage. If so,
By correcting the moving amount of the probe unit 4,
The pin probes 2, 2,... Can be reliably brought into contact with the circuit pattern. If warpage occurs,
It is preferable to measure the substrate thickness as close to the probe unit 4 as possible.

The present invention is not limited to the above embodiment. For example, as shown in FIG. 4, the probe unit 4a for controlling the movement may be composed of two pin probes 2 and 2, and even in such a case, the movement amount is calculated according to the equation shown in the present embodiment. Can be corrected.

The distance measuring means is not limited to the differential transformer type sensor 11, but may be a laser displacement meter or the like.
In such a case, if the laser displacement meter is arranged above the substrate 10 and the phase difference between the transmission signal and the reception signal is detected, the thickness error Δt is calculated based on the distance from the reference position to the surface of the substrate 10. be able to. Further, the thickness error Δt
Is indirectly calculated based on the distance from the reference position to the differential transformer type sensor 11 to the surface of the substrate 10 in the present embodiment.
May be measured directly.

[0035]

As described above, according to the substrate inspection apparatus of the first aspect, the distance measuring means measures the distance from the reference position to the surface of the substrate, and determines the distance when the substrate has a theoretical substrate thickness. When an error has occurred in comparison, the position correcting means corrects the position of the probe unit so as to cancel the error, so that there is an error in the substrate thickness or the substrate is locally warped. Even in this case, each pin probe can be accurately brought into contact with a circuit pattern having a predetermined pitch on the substrate surface.

According to the second aspect of the present invention, the distance measuring means can be configured simply and inexpensively by calculating the distance based on the sensor signal of the differential displacement sensor. it can.

Further, according to the substrate inspection apparatus of the third aspect, the substrate thickness measuring means directly measures the substrate thickness and compares the measured substrate thickness with the theoretical substrate thickness when an error occurs in the measured substrate thickness. The position correction means corrects the position of the probe unit so as to cancel the error, so that even if there is an error in the substrate thickness or the substrate is warped locally, , Each pin probe can be accurately brought into contact with a circuit pattern having a predetermined pitch.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a substrate inspection apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining the principle of controlling the moving amount of a probe unit in the board inspection apparatus according to the embodiment of the present invention.

FIGS. 3A and 3B are explanatory diagrams for explaining the principle of controlling the movement amount of a probe unit in the substrate inspection apparatus according to the embodiment of the present invention.

FIG. 4 is an external view showing another shape of the probe unit.

FIG. 5 is an explanatory diagram showing a usage example of a probe unit.

FIG. 6 is a cross-sectional view illustrating an internal structure of a probe unit already developed by the applicant.

FIG. 7 is a conceptual diagram illustrating a probe unit that has been already developed by the applicant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Board inspection apparatus 2 Pin probe 3 Unit main body 4 Probe unit 4a Probe unit 10 Substrate 11 Differential transformer type sensor 31 Control part

Claims (3)

[Claims] 1. A probe unit for holding a plurality of pin probes arranged in a fan shape so as to protrude from a unit body, separating said probe units by a predetermined distance from a substrate to be inspected, and said plurality of pin probes By projecting at least two of them from the unit main body, the tips of the protruded pin probes are brought into contact with the substrate surface, and the pitch between the tips is set to a length corresponding to the predetermined distance. A substrate inspection apparatus for inspecting a substrate, comprising: a distance measuring unit that measures a distance from a predetermined reference position to a surface of the substrate; and a position of the probe unit according to the distance measured by the distance measuring unit. A substrate inspection apparatus, comprising: a position correcting means for performing correction. 2. The distance measuring means includes a differential displacement sensor and a calculation unit that calculates the distance based on a sensor signal of the differential displacement sensor. The substrate inspection apparatus according to claim 1. 3. A probe unit for holding a plurality of pin probes arranged in a fan shape so as to protrude from a unit main body, separating said probe units by a predetermined distance from a substrate to be inspected, and said plurality of pin probes By projecting at least two of them from the unit main body, the tips of the protruded pin probes are brought into contact with the substrate surface, and the pitch between the tips is set to a length corresponding to the predetermined distance. A substrate inspection apparatus for inspecting a substrate, comprising: a substrate thickness measuring unit that measures a thickness of the substrate; and a position correction unit that corrects a position of the probe unit according to the thickness measured by the substrate thickness measuring unit. A substrate inspection apparatus comprising: