JP2001144147A - Device and method for inspecting surface-mounted package junction part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for inexpensively inspecting a surface-mounted package junction part, which can judge the quality of a solder junction part between the ball grid of a surface-mounted package and the pad part of a circuit board, even if electronic components are mounted on both faces of the circuit board, without the special need for safety measures. SOLUTION: A BGA-type LSI11 is loaded on a circuit board 10. The respective ball grids of BGA-type LSI11 are irradiated with light beams 17 from a projection part 15. The quantity of light passing between the ball grids 12 is detected by a light reception part. Passing light quantity 18 is measured by a measuring part 20 and is inputted to a decision part 21 as a measured result 19. The quality of the solder junction part of the ball grids 12 in BGA- type LSI, which are loaded on the circuit board 10, is decided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for inspecting a joint of a surface mount type package, and more particularly to a BGA (Bal Bal).
The present invention relates to an apparatus and a method for inspecting a junction part of a surface mount package of a (Grid Array) type.

[0002]

2. Description of the Related Art Conventionally, BGA (Ball Grid A)
(rray) LSI (LargeScale Int)
As a device for inspecting the joint when soldering a surface-mount type package such as an emulsion) to a circuit board,
There is a "solder joint inspection apparatus for semiconductor devices" described in Japanese Patent Application Laid-Open No. 04-35947. In this device, the joint between the ball grid of the semiconductor device and the pad of the circuit board is X
This is an apparatus for inspecting a bonding state using a line transmission image. That is, after the surface mounting type package is solder-connected to the circuit board, X-rays are irradiated from the back side of the circuit board, an X-ray photograph of the solder joint is taken, and the quality of the photographed result is visually judged.

On the other hand, in recent years, the number of cases where electronic components are mounted on a side opposite to a circuit board on which a surface mounting package is mounted by high-density mounting has been increasing.

[0004]

Since an X-ray apparatus is used for inspecting a solder joint of a conventional surface mount type package with a circuit board, the inspection apparatus is expensive, and safety measures are required. There was a problem.

Also, due to the high-density mounting, since electronic components are also mounted on the opposite side of the circuit board on which the surface mounting package is mounted, it is difficult to inspect the solder joint by X-ray photography. There are points.

SUMMARY OF THE INVENTION An object of the present invention is to provide a ball grid of a surface mount type package and a pad of a circuit board even when electronic components are mounted on both sides of a circuit board at low cost without requiring special safety measures. It is an object of the present invention to provide an apparatus and a method for inspecting a surface-mounted package bonding portion, which can determine the quality of a solder bonding portion of a portion.

[0007]

According to the present invention, there is provided a surface mount type package joint inspection apparatus which irradiates a light beam between respective grids of a ball grid of a surface mount type package mounted on a pad of a circuit board. And a light receiving unit for receiving the amount of light passing between the respective grids of the ball grid, a measuring unit for measuring the amount of passing light detected by the light receiving unit, and comparing the measurement result measured by the measuring unit with a reference light amount. A determination unit configured to determine the quality of a joint between the pad of the circuit board and the ball grid of the surface mount package.

The surface mount type package joint inspection apparatus according to the present invention is characterized in that a laser beam is used as a light source of a light projecting unit, and a light beam is branched between lattices of a ball grid of a surface mount type package mounted on a circuit board. And

The surface mount type package bonding portion inspection apparatus of the present invention is characterized in that an LED light source corresponding to each space between ball grids of a surface mount type package mounted on a circuit board is used as a light source of a light emitting unit. And

In the surface mount type package joint inspection apparatus according to the present invention, the light source of the light projecting unit is branched using an optical fiber array between the respective grids of the ball grid of the surface mount type package mounted on the circuit board. Irradiation.

According to the surface mount type package joint inspection method of the present invention, a light beam is emitted from a light projecting portion between the respective grids of a ball grid of a surface mount type package mounted on a pad of a circuit board. The amount of light passing between the lattices is detected by the light receiving unit, the detected amount of light is measured by the measuring unit, and the quality of the joint of the ball grid mounted on the pad of the circuit board is determined based on the measurement result from the measuring unit. Is determined.

According to the surface mount type package joint inspection method of the present invention, the measuring unit measures the total amount of light passing through each of the vertical and horizontal ball grids of the surface mount type package mounted on the circuit board. It is characterized in that the measurement result is input to a determination unit, and the pass / fail of the bonded portion is determined in advance by comparing with a reference value of the amount of transmitted light received in a normal solder bonding state.

[0013]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the basic configuration of a surface mount type package joint inspection apparatus according to the present invention.

Referring to FIG. 1, a surface mount type package mounted on a circuit board 10, ie, a BGA type LSI 1
1 is soldered by a ball grid 12.

FIG. 1 is a sectional view of a BGA type LSI 11 soldered to a circuit board 10.
A plurality of ball grids 12 are provided in a lattice pattern on the bottom surface of the BGA type LSI 11, and are soldered to pad portions of the circuit board 10, respectively.

The solder joint inspection unit 13 includes a light projecting unit 15 located on one side surface of the BGA type LSI 11, a light receiving unit 16 located on one side surface of the BGA type LSI facing the light projecting unit 15, and a support for connecting them. 14. Depending on the shape of the BGA type LSI 11,
The support 14 sets the interval between the light receiving unit 5 and the light receiving unit 16 at a predetermined interval.

The ball grid 1 detected by the light receiving section 16
The amount of passing light 18 that has passed between the two grids is measured by the measurement unit 20 and is input to the determination unit 21 as the measurement result 19.

As the light source of the light projecting unit 15, it is preferable to use a laser beam, an LED, or the like having a straight traveling property. The number of light sources is branched by an optical fiber or the like into a number between the lattices of the ball grid 12 to be inspected in the light projection direction of the BGA type LSI 11. The opposing light receiving units 16 include sensors for detecting the amount of light passing between the respective lattices.

Next, the operation of the surface mount type package joint inspection apparatus according to the present invention shown in FIG. 1 will be described with reference to the drawings.

Light emitting part 1 of solder connection part inspection unit 13
The light beam 17 emitted from 5 passes through the spaces between the ball grids 12 and is sensed by the light receiving unit 16 in order to determine the quality of the solder joint between the BGA type LSI 11 and the circuit board. The passing light amount 18 detected by the light receiving unit 16 is a light beam 17
Of the ball grid 12 in the light projection direction of the light of the BGA type LSI 11. Measurement unit 1
Numeral 8 measures the passing light amount 18 detected by the light receiving unit 16.
The measurement result 19 measured by the measurement unit 20 is input to the determination unit 21 and compared with the light amount of a preset reference value.
It is configured to determine the success or failure of the solder bridge between the grids of the ball grid 12 in the light projection direction of the light beam of the mold LSI 11 and the solder joint between the pads of the circuit board.

Next, a method of inspecting a joint portion of a surface mount type package according to the present invention will be described in detail with reference to the drawings.

FIGS. 2 and 3 show a BGA type LS according to the present invention.
It is a block diagram explaining the inspection method of the joining part of the ball grid of I and the pad of a circuit board.

FIGS. 2 and 3 both have a device configuration that allows simultaneous inspection of vertical and horizontal grids for joint failure when a ball grid of a BGA type LSI is solder-bonded to a pad of a circuit board. That is, the light projecting unit 15x and the light receiving unit 16x, and the light projecting unit 15y and the light receiving unit 16y are arranged on opposing side surfaces of the BGA type LSI, respectively. The passing light amounts 18x and 18y in the light projection direction of the respective lights detected by the light receiving units 16x and 16y are input to the measuring unit 22.
The judging unit 23 compares the reference value of the light quantity set in advance with the total light quantity passing between the grids of the ball grids 12 of the vertical and horizontal BGA type LSI, and joins between the grids of the ball grid or between the pads of the circuit board. It is configured to determine the presence or absence of a part failure.

FIG. 2 shows a ball grid 1 of a BGA type LSI.
2 shows a bonding state between the ball grid 12 of the BGA type LSI in which no solder bridge is generated between the pads of the circuit board 2 and the pads of the circuit board. In this case, since the light beams 17 emitted from the light projecting portions 15x and 15y have no obstacle between the grids of the vertical and horizontal ball grids 12 due to a defective solder connection portion such as a solder bridge, the amount of the light beams 17 Without loss of light,
A predetermined light amount is detected at x and 16y. The sum of the passing light amount 18x and the passing light amount 18y measured by the measuring unit 22 is input to the determining unit 23 as a measurement result 24, and is compared with a reference value preset in the determining unit 23. In FIG. 2, since there is no solder bridge in each grid between the ball grid 12 and the pads of the circuit board, it is determined that there is no defect in the solder joint at the joint between the BGA LSI and the circuit board.

FIG. 3 shows a bonding state in which a solder bridge is generated between the ball grid of the BGA type LSI or the pad of the circuit board.

Referring to FIG. 3, a defective solder joint, that is, a solder bridge 25, occurs between the ball grids 12a and 12b of the BGA type LSI. In this case, of the light beams emitted from the light projecting unit 15y, the ball grid 1
The light beam 26 passing between the gratings 2a and 12b is blocked by the solder bridge 25, and the light beam does not reach the corresponding light receiving portion 16y or the amount of light received decreases. as a result,
Since the total light amount measured by the measuring unit 22 is smaller than the case without the solder bridge, the determining unit 23 determines that the total light amount is equal to or less than the light amount of the preset reference value, and the BGA type LS
Defective solder joints between the ball grid of I and the pads of the circuit board can be detected.

FIG. 4 is a view showing various forms of a solder bridge between ball grids generated when a BGA type LSI is mounted on a circuit board.

The bridge 27 shows a state in which the space between the ball grids 12a and 12b is completely buried. The bridge 28 shows a state in which a solder bridge is generated with a gap left on the upper side and the lower side between the ball grid 12b and the ball grid 12c. Furthermore, the bridge 29 is connected to the ball grid 12c and the ball grid 12
This shows a state in which a solder bridge is generated with a gap left above d. When the bridge 27 occurs, the light passing between the ball grids is completely blocked, so that the solder bridge can be easily detected by the presence or absence of the light amount sensor on the light receiving side. In the case of the bridge 28 and the bridge 29, the bridge between the ball grids is not completely bridged, but a threshold is provided in advance for the light receiving level, the light receiving level is measured on the light receiving side, and the light receiving level is compared with the threshold. Detectable by method. In addition, it is possible to detect a solder bridge by previously setting the area of a region that can pass between ball grids and comparing the light receiving area with the predetermined area on the light receiving side. Furthermore, it is also possible to detect a solder bridge by previously setting the shape of an area that can pass between the ball grids and comparing the light receiving shape with the set shape on the light receiving side.

Next, a description will be given of another embodiment of the surface mount type package joint inspection apparatus according to the present invention.

FIG. 5 shows the configuration of another embodiment of the apparatus for inspecting the joint portion of a surface mount type package according to the present invention.

BGA type LS generally mounted on a circuit board
Although there are various sizes of I, a modification of the embodiment for enabling the inspection of the joint between the ball grid of the BGA type LSI and the pad of the circuit board having different sizes will be described.

Referring to FIG. 5, the light projecting unit 15 and the light receiving unit 1
An adjustment unit 31 is provided so that the interval of No. 6 can be changed according to the size of the BGA type LSI 11. The light projecting unit 15 connected to the support 14a and the light receiving unit 16 connected to the support 14b can be moved by the adjusting unit 31 to adjust the distance between the light projecting unit 15 and the light receiving unit 16.

[0034]

As described above, the bonding portion inspection apparatus for a surface mount type package according to the present invention is inexpensive, does not require special safety measures, and has electronic components mounted on both sides of a circuit board. Also, it is possible to determine the quality of the solder joint between the ball grid of the surface mount package and the pad of the circuit board.

The reason for this is that a light projecting unit and a light receiving unit are respectively installed on opposing surfaces of a surface mount type package mounted on a circuit board, and a laser beam or LED light having linearity is transmitted from the light projecting unit to a ball grid. This is because a configuration and a method are adopted in which the light is irradiated between the lattices, the light amount of the light receiving unit is measured by the measuring unit, and the measurement result input by the determining unit is compared and determined with a preset reference light amount.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a surface mount type package joint inspection apparatus according to the present invention.

FIG. 2 is a block diagram illustrating a method for inspecting a joint between a ball grid of a BGA type LSI and a pad of a circuit board according to the present invention.

FIG. 3 is a block diagram illustrating a method of inspecting a joint between a ball grid of a BGA type LSI and a pad of a circuit board according to the present invention.

FIG. 4 is a view showing various forms of a solder bridge between ball grids generated when a BGA type LSI is mounted on a circuit board.

FIG. 5 is a configuration diagram of another embodiment of the surface inspection type package joint inspection apparatus of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Circuit board 11 BGA type LSI 12, 12a, 12b, 12c, 12d Ball grid 13 Solder connection inspection unit 14, 14a, 14b Support 15, 15x, 15y Light emitting part 16, 16x, 16y Light receiving part 17 Light beam 18, 18x , 18y Passing light amount 19 Measurement result 20 Measurement unit 21 Judgment unit 22 Measurement unit 23 Judgment unit 24 Measurement result 25 Solder bridge 26 Light beam 27, 28, 29 Bridge

Claims (6)

[Claims] 1. An apparatus for inspecting a joint of a surface mounted package, comprising: a light projecting unit for irradiating a light beam between respective grids of a ball grid of the surface mounted package mounted on pads of a circuit board; A light receiving unit that receives the amount of light passing between the lattices, a measuring unit that measures the amount of passing light detected by the light receiving unit, and a pad on the circuit board that compares the measurement result measured by the measuring unit with the reference light amount. A bonding unit for determining whether a bonding portion between the surface mounting package and the ball grid is good or bad, the bonding inspection device for a surface mounting package. 2. A light source according to claim 1, wherein a laser beam is used as a light source of the light projecting unit, and the light beam is branched between lattices of a ball grid of a surface mount type package mounted on a circuit board.
A bonding inspection apparatus for a surface-mounted package according to the above. 3. A surface mount type package joint inspection apparatus, wherein an LED light source corresponding to a space between ball grids of a surface mount type package mounted on a circuit board is used as a light source of a light projecting unit. 4. A light source of a light projecting unit for irradiating a light beam by branching between respective grids of a ball grid of a surface mount type package mounted on a circuit board using an optical fiber array. A bonding inspection apparatus for a surface-mounted package according to the above. 5. A method for inspecting a joint of a surface-mounted package, comprising: irradiating a light beam from a light projecting portion between respective grids of a ball grid of the surface-mounted package mounted on pads of a circuit board; The amount of light passing between the lattices is detected by the light receiving unit, the detected amount of light is measured by the measuring unit, and the quality of the joint of the ball grid mounted on the pad of the circuit board is determined based on the measurement result from the measuring unit. And a method for inspecting a joint portion of a surface mount package. 6. A measuring unit measures the total amount of light passing between each of the vertical and horizontal ball grids of a surface mount package mounted on a circuit board, and inputs the measurement result to a judging unit. 6. The method for inspecting a joint of a surface mount package according to claim 5, wherein the quality of the joint is determined by comparing with a reference value of a passing light amount received in a proper solder joint state.