JPH10111314A - probe - Google Patents

Abstract

(57) Abstract: Provided is a novel probe capable of performing an individual test on a multi-pin electronic component such as a BGA device mounted on a wiring board. A pin contact portion is provided at one end of an arm of an elastic member made of a bifurcated thin plate and pinches a pin between opposing notches, and a pair of guide portions for guiding the pin to the pin contact portion. And a pin retreating portion formed between the arms on the opposite side of the guide portion with respect to the pin contact portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for testing a mounted printed circuit board, and more particularly to a method for easily testing a mounted printed circuit board on which a multi-pin electronic component such as a BGA (Ball Grid Array) type is mounted. About the probe that can be. In recent years, multi-pin LSIs such as BGA type, which can cope with high integration, high speed and high power, and have a low-cost package structure, have been used for various electronic devices such as mobile phones. In order to ensure the reliability of electronic devices, it is necessary for manufacturers to perform device tests on multi-pin electronic components such as BGA types mounted on printed circuit boards.
The emergence of new probes for use in such tests is desired.

[0002]

2. Description of the Related Art In general, a mounted printed circuit board incorporated in an electronic device such as a mobile phone has a footprint of a predetermined pattern formed on the surface of the printed circuit board, and a predetermined amount of creamy solder is applied on the footprint. Later, chip components such as resistors and capacitors, SOP, QFP, PG
A and BGA type semiconductor devices are called SMT
(Surface mounting technology), and completed by soldering with a reflow device.

[0003] The completed printed circuit board is inspected by using an in-circuit tester or the like using a dedicated fixture equipped with probe pins for inputting / outputting an inspection signal. Detect defective parts and components, repair them, and then perform a functional test to determine the quality of the mounted printed circuit board.

However, the probe pins mounted on the fixture of the in-circuit tester cannot contact arbitrary pins (solder bumps) of the BGA device mounted on the mounting printed circuit board due to the following reasons due to the package structure. Met. Therefore, the test of each BGA device mounted on the mounted printed circuit board has not been performed.

FIG. 5 shows a mounted printed circuit board on which a BGA device is mounted. In FIG. 5, reference numeral 2 denotes a mounting printed circuit board, and reference numeral 3 denotes a BGA device, which is mounted on a footprint formed on the surface of the mounting printed circuit board 2 so that the array-shaped pins on the back surface of the package body are in contact with each other. Soldered. 4 is SOP type I
C and 5 are chip parts such as resistors and capacitors, BGA
It shows a state where it is mounted in the same way as the device and then soldered.

The joint between the array pins and the footprint of the BGA device 3 mounted and soldered on the mounting printed circuit board 2 is covered with the package body of the BGA device 3. The array-shaped pins of the BGA device 3 have a barrel-like shape with the center bulging when soldered. The diameter of the center is about 0.8 mm and the height is about 0.5 to 0.6 mm. Become. This height corresponds to a gap value between the surface of the mounting printed circuit board 2 and the bottom surface of the package body of the BGA device 3. That is, it is not easy to make contact with the pins located near the center of the package body, especially in a bonding structure in which a large number of pins are arranged in the gap between the BGA device 3 and the mounting printed circuit board 2 in this narrow gap.

For these reasons, the test of the BGA device 3 itself after mounting has not been performed by the in-circuit tester. Further, in the conventional hand-held probe, it is possible to contact the pins located around the package, but it is not easy to contact the pins near the center of the package body. Therefore, even if a conventional hand-held probe is used, the test of the BGA device 3 itself has not been performed.

[0008]

As described above, an object of the present invention is to easily test individual multi-pin electronic components such as a BGA device 3 mounted on a conventionally mounted printed circuit board. It is an object of the present invention to provide a novel probe which can easily contact even a pin located nearby.

[0009]

In order to solve the above problems, a probe according to the present invention is provided at one end of an arm of an elastic member made of a bifurcated thin plate and opposed to each other. A pin contact portion for pinching the pin by the notch, a pair of guide portions for guiding the pin to the pin contact portion, and a pin retreat formed between the arm opposite to the guide portion with respect to the pin contact portion And a unit.

The probe according to the second aspect of the present invention is the first aspect of the present invention.
And an insulating coating is provided on the entire surface of the arm other than the pin contact portion. In the probe according to the first and second aspects,
Easy access to pins near the center of the package body.

[0011]

FIG. 1 shows a first embodiment of the present invention.
FIG. 1 is a plan view showing a probe 1 for testing a GA device. In the probe 1 of this embodiment, an arm, a stylus portion, and a terminal are integrally formed of a conductive material. FIG. 1 shows a probe 1 for testing a standard 1.27 mm pitch, 225 pin BGA device 3. 0.3 wall thickness
A metal mold is made by punching a thin conductive material such as a copper-based alloy plate or an aluminum-based alloy plate.

This metal mold has a forked shape,
The arm AR is a part with a width of 0.3 mm extending parallel to the fork.
It is called AL, and a stylus portion K is formed near the tip of each arm. Further, the bifurcated base is fixed to a rod-shaped grip Q made of an insulating resin so that the probe 1 can be easily gripped. The shape and length of the grip Q are not particularly limited, but may be, for example, a columnar body, a rectangular parallelepiped, or the like, and the length may be such that the operator can easily hold it with one hand.

On the other hand, as the metal-type material, other than the above-mentioned materials, any material having excellent electric conductivity, elasticity, and high rigidity may be used, but it is particularly preferable that the workability is easy. . Next, individual portions formed in the forked metal mold will be described in detail. The stylus K at the tip of the arm
When the probe 1 is further advanced after the pin B has come into contact with the stylus portion K, a sliding portion SF serving as a pair of guide portions for guiding the pin B to a pin contact portion of the stylus portion K described later smoothly.
R and SFL are provided.

Further, the notches NR, N
L are provided so as to face each other, and are formed by both the notches NR and NL which face each other when the stylus K is closed to form a pin contact portion. For this reason, the notches NR and NL have the same curvature as the pin B so that the pin B can be securely clamped. Further, in order to smoothly move the pin B from the pin contact portion by communicating with the notch portions NR, NL, the sliding portions SRR, SR
L is provided. The two arms AR and AL are arranged in parallel between the sliding portions SRR and SRL and the grip Q, but the distance between the two arms is set to be substantially larger than the diameter of the pin B, so that the two arms AR and AL are in the row of pins B and are in contact with each other. Unnecessary pins are arm AR,
It becomes a pin retreat part which can retreat the pin without contacting the AL. If the length of the arms AR and AL is at least half the length of one side of the package outer shape of the BGA device 3 to be inspected, all the pins B are contacted with pins B from four directions around the package. Can be brought into contact with each other. Therefore, the length of the arm of this embodiment is approximately 12 m.
m.

At the position near the grip Q, the arms AR, A
When at least one arm of L is provided with a terminal U, a signal cable H is connected to the terminal U, and a pin B is pinched by a pin contact portion of the stylus K, an electric signal taken out from the pin B is transferred to the arm. And sends it to a pin B via a reverse route.

Next, a state in which the operator grips the grip Q with one hand and contacts a desired pin of the BGA device 3 to be inserted into a gap between the BGA device 3 and the mounting printed circuit board 2 is shown in FIGS. The operation of pin contact by the probe 1 of the present invention will be described with reference to FIG.

FIG. 3 is a plan view showing the movement of the stylus portion K of the probe 1 according to the present invention, and FIG. 4 is a plan view showing the movement of the probe 1.
FIG. 2 is a perspective view of a gap between a device 3 and a mounted printed circuit board 2. As shown in FIG. 3, for example, along a row of pins B including a target pin B4 with which the stylus portion K is to be brought into contact,
When the probe is moved in the Y direction, as shown in FIG. 4, the stylus portion K contacts the pin B1 (A), and when the probe 1 is further advanced in the Y direction, it is formed on the two arms AR and AL. The sliding portions SFR and SFL serving as guide portions are deformed in the direction orthogonal to the Y direction and pushed open (B), and finally, pins formed by both opposing notches NR and NL provided in the stylus portion K. The contact catches the pin B1 (C). When the probe 1 is further advanced in the Y direction, the stylus portion K is pushed and opened again (D), and the pin B1 eventually escapes from the pin contact portion of the stylus portion K (E). In this process, the moment when the pin contact portion of the stylus portion K catches the pin B1, the pin B1
The operator feels a click in his hand both at the moment when he escapes from the pin contact portion.

When the probe 1 is advanced in the Y direction as shown in FIG. 3, the pin contact portion of the stylus K eventually reaches the target pin B4. (See FIG. 3 (E).) The worker advances the probe 1 along the row of pins B including the target pin B4, and counts the number of times the hand feels a click. It grasps which pin B the pin contact part of the needle part K catches, and finally,
The pin contact portion of the stylus portion K can be guided to the target pin B4. During this time, the operator does not need to directly visually confirm the positional relationship between the pin contact portion of the stylus K and the target pin B4.

The stylus portion K securely pinches the pin B4 at the pin contact portion by a force of the arm AR or AL that attempts to return to its original position due to its own elastic force. Grip Q from the pin contact portion where pin B4 is clamped through arms AR and AL
Since the terminal provided near the terminal is formed of a conductive material, if the signal cable H is connected to the terminal, the pin B4
From the outside, or it is possible to input the electric signal from the outside to the pin B4 through the reverse route.

In the present invention, the tip of the probe 1 can be brought into contact with the pin at the desired position in this way. Next, the probe 11 according to the second embodiment of the present invention will be described.
Will be described. FIG. 2 shows the second probe 11 of the present invention.
FIG. 2 is a plan view of a probe 1 for testing a BGA device.
1 is shown.

The second probe 11 has the same shape as the probe 1 shown in FIG. 1, and only different points will be described. After punching a copper-based alloy plate or an aluminum-based alloy plate to form a metal mold, the entire metal mold is coated with a resin insulating film O having a thickness of about 20 μm by an electrodeposition coating method or the like. Since the entire metal mold is covered with the insulating film O, the portion of the insulating film O in contact with the pin B of the pin contact portion is replaced with a known photolithography.
The pads PR and PL are formed by selectively removing the metal surfaces by an etching process to expose the metal surfaces. Electrical conduction can be achieved between the pins B and the pads PR and PL formed at the pin contact portions.

Since the terminal U is also covered with the insulating film O, the insulating film O on the surface is removed in the same manner as described above, and the signal cable H is connected. In the second embodiment,
When the pin which does not need to be contacted is retracted in the pin retracting portion, since the above-described insulating coating O is coated on the entire surface of the arm, even if the pin contacts the side surface of the arm,
No electrical connection is established between the pin and the arm. Therefore, it is possible to completely prevent the destruction of the BGA device caused by erroneously contacting a pin that does not require contact and applying an input signal.

In the above-described embodiment of the present invention, the arm, the stylus portion, and the terminal are integrally formed by punching a bifurcated metal mold. When fixing with a grip, a bifurcated shape may be formed by connecting both arms with a metal plate and wire wiring at the fixed portion. Further, the cable may be led out from the fixed portion of the grip without providing the terminal portion.

As described above, in addition to the above, various modifications can be made according to the gist of the present invention.

[0025]

As described above, according to the present invention,
With the test of each multi-pin type electronic component such as a BGA device mounted on a printed circuit board, the stylus portion of the probe can be easily brought into contact with a desired pin of the electronic component. It is possible to improve the efficiency of the operation for identifying the defective portion of the circuit board.

[Brief description of the drawings]

FIG. 1 is a plan view showing a probe of the present invention.

FIG. 2 is a plan view showing a second probe of the present invention.

FIG. 3 is a plan view showing the movement of the probe of the present invention.

FIG. 4 is a plan view showing the movement of a stylus portion K of the probe of the present invention.

FIG. 5 is a perspective view of a mounted printed circuit board after BGA mounting.

[Explanation of symbols]

 1, 11 probe 2 mounting printed circuit board (wiring board) 3 BGA device AL, AR arm B pin H signal cable K stylus NL, NR notch O insulation coating PL, PR pad Q grip SFL, SFR sliding part SRL, SRR Sliding part U terminal

Claims (2)

[Claims] 1. A probe for contacting a pin of a multi-pin electronic component mounted on a wiring board, the probe being provided at one end of an arm of an elastic member made of a bifurcated thin plate and sandwiching the pin with an opposing notch. A pin contact portion, a pair of guide portions for guiding the pin to the pin contact portion, and a pin retracting portion formed between the arms on the opposite side of the guide portion with respect to the pin contact portion. Probe to be characterized. 2. The probe according to claim 1, wherein an insulating coating is provided on the entire surface of the arm other than the pin contact portion.