JP2003152329A - Method and device for dismounting ball grid array mounted on printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for dismounting a ball grid array mounted on a printed wiring board, which is capable of reducing thermal damage to the printed wiring board and parts mounted on the wiring board around the BGA to an irreducible minimum. SOLUTION: This method of dismounting a ball grid array 12 mounted on a printed wiring board comprises a first step of arranging the printed wiring board 10 so as to position the ball grid array 12 inside a solder jet nozzle 8, a second step of bringing molten solder 24 inside the solder jet nozzle 8 into contact with the main body of the ball grid array 12 to melt the solder balls 26 of the ball grid array 12 by heat conduction of the main body, and a third step of dismounting the ball grid array 12 to a molten solder 24 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for removing a ball grid array (BGA) mounted on a printed wiring board.

Due to advances in surface mount technology (SMT), surface mount parts (S) mounted on a circuit board such as a printed wiring board.
There are various forms of MD, but in recent years, BGA has been actively used as one of surface mount components, and its size and the number of pins are remarkable.

The BGA accommodates an IC chip inside a rectangular parallelepiped package made of synthetic resin or ceramics, and has a plurality of terminals regularly arranged in a grid on the back surface of the package and connected to the IC chip. , And solder balls are fused to the respective terminals.

To mount on a printed wiring board and make a solder connection, a conductor pattern for soldering is formed on the surface of the printed wiring board, and a cream-like solder paste is applied to the surface of the conductor pattern by a printing method, and then a solder paste is applied. Then, the BGA is accurately mounted, the whole is sent to a heating furnace to melt the solder, and the solder is cooled to perform solder connection.

However, defects in cream solder printing (rubbing, excess, misalignment, etc.), misalignment, printed wiring board and BG
Unsolder due to warpage or deformation during reflow soldering of the A main body, bridge failure, etc. may occur depending on the manufacturing conditions and type of parts, and solder bridges and unconnected (open) failures in the functional test and X-ray inspection process, IC itself If a defect is detected B
GA must be replaced.

[0006] Further, the need to replace the BGA may arise due to the design change of the BGA. In such a case, it is necessary to remove only the relevant BGA and re-mount a new BGA, but there is a demand for the development of a repair method that does not damage the printed wiring board and surrounding parts.

[0007]

2. Description of the Related Art In a normal process of mounting a BGA on a printed wiring board and mounting it by soldering, the procedure described above can be performed, but it is necessary to replace the BGA after mounting the BGA on the printed wiring board. When comes out, its removal is not easy.

The reason why it is not easy to replace the BGA is that the BGA is
A large number of small chip components and SMDs of other ICs are mounted at high density on the component surface and the back surface in the vicinity of, and it is necessary to remove only the BGA that needs to be replaced without adversely affecting the surrounding components and the board. Because there is.

Conventionally, a temperature profile is taken in advance for a BGA mounting portion of a printed wiring board as a sample, and the BGA is mounted on the printed wiring board using hot air or the like through a nozzle with a temperature profile set from the upper portion and the lower portion. To prevent distortion (warping, twisting, etc.) on the printed wiring board by heating, preheat the entire printed wiring board to around 100 ° C without heating only the local parts of the printed wiring board, and use solder balls with hot air etc. It melted and removed BGA.

[0010]

Therefore, the area around the BGA of the printed wiring board is heated to about 220 ° C. at which the solder melts, the thermal damage to the printed wiring board is large, and the distortion of the printed wiring board is suppressed. It was difficult. In addition, the reliability of the surrounding parts was also reduced due to thermal damage.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a printed wiring capable of minimizing the thermal damage to surrounding parts and the distortion of the printed wiring board. A method and an apparatus for removing a BGA mounted on a board.

[0012]

According to one aspect of the present invention, there is provided a method of removing a ball grid array mounted on a printed wiring board, the printed wiring being arranged such that the ball grid array is positioned in a solder jet nozzle. A plate is arranged, the molten solder in the solder jet nozzle is brought into contact with the main body of the ball grid array, the solder balls of the ball grid array are melted by heat conduction of the main body, and the drawing force of the molten solder by stopping the jet flow and the A method of removing a ball grid array mounted on a printed wiring board, characterized in that the ball grid array is removed to the molten solder side by its own weight.

Since only the main body of the ball grid array is heated by the molten solder and the solder balls of the ball grid array are melted by the heat conduction of the main body, heat damage to surrounding parts and distortion such as warpage of the printed wiring board occur. There is nothing to do.

According to another aspect of the present invention, there is provided a device for removing a ball grid array mounted on a printed wiring board, the container containing molten solder and having at least one opening on an upper surface, and the opening. An apparatus for removing a ball grid array mounted on a printed wiring board is provided, comprising: a solder jet nozzle detachably attached to the solder jet nozzle; and a jet means for generating a solder jet in the solder jet nozzle. It

Preferably, the ball grid array removing device further comprises a jet height adjusting means for adjusting the height of the solder jet in the solder jet nozzle, and a timer for setting the solder jet time.

According to still another aspect of the present invention, there is provided a method of removing a ball grid array mounted on a printed wiring board, wherein the ball grid array is placed under a main body of the ball grid array in a direction away from the printed wiring board. Inserting a spring for biasing, selectively non-contact heating only the main body of the ball grid array with a light beam heating device,
A method for removing a ball grid array mounted on a printed wiring board is provided, in which the solder balls of the ball grid array are melted by the conductive heat of the main body and the ball grid array is lifted by the spring.

According to another aspect of the present invention, there is provided a method of removing a ball grid array mounted on a printed wiring board, the ball grid array being below the main body of the ball grid array in a direction away from the printed wiring board. Insert a spring to bias the heater block into contact with the body of the ball grid array to heat the body, the conductive heat of the body melts the solder balls of the ball grid array, and the solder balls melt. When mounted on a printed wiring board, the displacement of the heater block that descends is sensed, the heater block is raised according to the sensing of the displacement, and the ball grid array is lifted by the spring. A method of removing a ball grid array is provided.

Instead of detecting the displacement of the heater block,
The temperature sensor may detect the melting temperature of the solder ball, and the heater block may be raised according to the detection of the melting temperature.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there is shown a perspective view of a ball grid array (BGA) removing device 2 according to a first embodiment of the present invention. The BGA removing device 2 has a container (solder device) 4 containing molten solder therein, and this container 4 is provided with a heater (not shown) for heating the molten solder to about 250 ° C.

The container 4 has an opening 5 at its top,
The opening 5 is closed by a jig 6 provided with a solder jet nozzle 8 for jetting solder only on the outer shape of the main body of the BGA to be removed.

The solder jet nozzle 8 is attachable to and detachable from the jig 6, and is set according to the number of BGAs to be removed. Jig 6
Has a plurality of openings in which the solder jet nozzles 8 are set, and the openings in which the solder jet nozzles 8 are not set are closed by a cover.

Reference numeral 10 is a printed wiring board on which a plurality of BGAs 12 are mounted. The printed wiring board 10 is set on the jig 6 using the printed wiring board setting mechanism 14 with the BGA 12 to be removed facing down. .

Reference numeral 16 is a jet motor, and the jet motor 16
A solder stirring member (not shown) is attached to the output shaft of. The jet height adjusting knob 18 controls the number of revolutions of the jet motor 16 to adjust the height of the solder jet. The solder jet time is set by the timer 20, and the thermometer 22
Detects the temperature of the molten solder.

FIG. 2 is a sectional view showing a solder jet state.
The temperature of the molten solder 24 is adjusted to about 250 ° C. When the jet motor 16 is driven, the solder agitating member is rotated and the molten solder 24 is agitated to generate a solder jet.

This solder jet rises in the solder jet nozzle 8 set in the opening of the jig 6, and the main body 13 of the BGA 12
The height of the solder jet is adjusted by the jet height adjusting knob 18 so that the solder jet comes into contact with the solder. Reference numeral 25 is a rising surface of the molten solder.

The body 13 of the BGA 12 is heated at a stretch by the large heat capacity of the molten solder 24, and the heat conduction of the body 13 heats and melts the solder balls 26. Depending on the thermal conductivity and heat capacity of the main body 13 of the BGA 12, the melting temperature of the solder ball 26 is reached in about 20 to 40 seconds, although there are variations.

The time until melting of the solder balls 26 can be set by observing the melting state of the solder balls 26 of the first BGA 12. When that time is set in the jet timer 20 and the solder jet is turned off, as shown in FIG.
Since the molten solder 24 that was in contact with the main body 13 of A12 descends, the drawing force and the weight of the BGA 12 at that time pull the BGA 12 toward the molten solder 20 and remove it from the printed wiring board 10.

Reference numeral 28 is a receptacle for preventing the removed BGA 12 from falling into the molten solder 24. Two
Reference numeral 7 indicates a descending surface of the molten solder 24.

In this embodiment, the printed wiring board 10 is not preheated, and only the main body 13 of the BGA 12 is melted with the solder 2.
Heat at 4. Further, according to the present embodiment, by mounting the plurality of jet solder nozzles 8 on the jig 6, it is possible to simultaneously remove the plurality of BGAs 12.

FIG. 4 is a schematic block diagram of the second embodiment of the present invention. A leaf spring 30 having a pair of claw portions 30a as shown in FIG. 5A is inserted into the gap between the printed wiring board 10 and the BGA 12. The leaf spring 30 has a biasing force that biases the BGA 12 away from the printed wiring board 10 as shown in FIG.

The leaf spring 30 is made of, for example, stainless steel having a thickness of 0.1 to 0.2 mm, and has a gap (0.15 to 0.15) between the printed wiring board 10 and the body 13 of the BGA 12.
It has a sufficient thinness to enter (0.25 mm). The spring force of the leaf spring 30 is set to about 12 grams.

The leaf spring 30 is put under the main body 13 of the BGA 12, and the BGA 12 is set in a state where it is constantly lifted by its spring force. This spring force needs to be a sufficiently small value that does not apply stress to the connection portion of the BGA 12.

Reference numeral 31 is a light beam heating device, which reflects a light beam from a high power light source 32 such as a halogen lamp or a xeron lamp by a reflecting mirror 34 to selectively heat the main body 13 of the BGA 12 in a non-contact manner. Reference numeral 36 is an irradiation area changing plate.

The conduction heat of the body 13 of the BGA 12 causes BGA 1
The second solder ball 26 is melted. When the solder balls 26 are melted, the spring force of the leaf spring 30 inserted under the BGA 12 peels off the molten solder, lifts the BGA 12, and completes the removal of the BGA.

Also in this embodiment, since only the main body 13 of the BGA 12 to be removed by the light beam heating device 31 is selectively non-contact heated, the parts around the BGA 12 and / or the printed wiring board 10 are not damaged. .

FIG. 6A shows a schematic block diagram of the third embodiment of the present invention. In the present embodiment, the high heat capacity heater block 38 having the heater 40 is provided in the main body 1 of the BGA 12.
It is pressed into contact with 3 and heated.

As with the second embodiment, the printed wiring board 1
A leaf spring 30 that urges the BGA 12 in a direction away from the printed wiring board is inserted in the gap between 0 and the BGA 12.

The heater block 38 is used for the main body 1 of the BGA 12.
When 3 is contact-heated, the conductive heat of the main body 13 melts the solder balls 26. When the solder balls 26 are melted, the gap between the printed wiring board 10 and the BGA 12 becomes smaller due to the pressing force of the heater block 38, so the displacement amount (0.05 to 0.10 mm) is detected by the displacement detection sensor 42. Then, the heater block 38 is raised, and the BGA 12 is lifted by the spring force of the leaf spring 30 inserted under the BGA 12 as shown in FIG. 6B, and the BGA is removed.

Also in this embodiment, the contact heating of the heater block 38 heats only the main body 13 of the BGA 12 to melt the solder balls 26, so that the parts around the BGA 12 and / or the printed wiring board 10 are not damaged. Absent.

FIG. 7 shows a schematic block diagram of the fourth embodiment of the present invention. In the present embodiment, the temperature sensor 44 is used to raise the heater block 38 instead of the displacement detection sensor 42 of the third embodiment. Another configuration of this embodiment is shown in FIG.
This is similar to the third embodiment shown in (A).

The temperature sensor 44 is kept in contact with the solder bump 26, and the temperature of the solder bump 26 is monitored. When the solder bump 26 reaches the melting temperature, the heater block 38 is raised, and the BGA 12 is lifted and removed by the spring force of the leaf spring 30 put under the BGA 12. Also in this embodiment,
The same effect as that of the third embodiment shown in FIG. 6A can be expected.

The present invention includes the following supplementary notes.

(Supplementary Note 1) A method of removing a ball grid array mounted on a printed wiring board, the printed wiring board having the ball grid array mounting surface facing downward so that the ball grid array is positioned in the solder jet nozzle. A method for removing a ball grid array mounted on a printed wiring board, characterized in that the molten solder in the solder jet nozzle is brought into contact with the main body of the ball grid array.

(Supplementary Note 2) A device for removing a ball grid array mounted on a printed wiring board, the container containing molten solder and having an opening for inserting the ball grid array from above on the upper surface, A device for removing a ball grid array mounted on a printed wiring board, comprising: a solder jet unit that supplies molten solder into the opening.

(Supplementary Note 3) A method for removing a ball grid array mounted on a printed wiring board, comprising a spring for urging the ball grid array in a direction away from the printed wiring board under the main body of the ball grid array. A method for removing a ball grid array mounted on a printed wiring board, which comprises inserting and heating the main body of the ball grid array in a non-contact manner with a light beam heating device.

(Supplementary Note 4) A method of removing a ball grid array mounted on a printed wiring board, wherein the printed wiring board is arranged so that the ball grid array is located in the solder jet nozzle, and The molten solder is brought into contact with the main body of the ball grid array, the solder balls of the ball grid array are melted by thermal conduction of the main body, and the ball grid array is pulled by the pulling force of the molten solder by stopping the jet flow and the weight of the ball grid array. The method for removing a ball grid array mounted on a printed wiring board is characterized in that the method is removed to the molten solder side.

(Supplementary Note 5) A device for removing a ball grid array mounted on a printed wiring board, the container containing molten solder and having at least one opening on the upper surface, and detachably attached to the opening. An apparatus for removing a ball grid array mounted on a printed wiring board, comprising: a solder jet nozzle that is provided; and jet means that generates a solder jet in the solder jet nozzle.

(Supplementary Note 6) The supplementary statement 5, further comprising: a jet height adjusting means for adjusting the height of the solder jet in the solder jet nozzle; and a timer for setting the solder jet time. A device for removing a ball grid array mounted on a printed wiring board.

(Supplementary Note 7) A method for removing a ball grid array mounted on a printed wiring board, comprising a spring for biasing the ball grid array in a direction away from the printed wiring board under the main body of the ball grid array. Inserting, non-contact heating the main body portion of the ball grid array with a light beam heating device, melting the solder balls of the ball grid array by the conductive heat of the main body, lift the ball grid array by the spring, A method for removing a ball grid array mounted on a characteristic printed wiring board.

(Supplementary Note 8) A method for removing a ball grid array mounted on a printed wiring board according to supplementary note 7, wherein only the main body of the ball grid array is selectively heated in a non-contact manner by using an illumination area changing plate.

(Supplementary Note 9) A method for removing a ball grid array mounted on a printed wiring board, comprising a spring for urging the ball grid array in a direction away from the printed wiring board under the main body of the ball grid array. Inserting, heating the body by contacting the heater block with the body of the ball grid array, and sensing the amount of displacement of the heater block that descends when the solder balls melt,
A method of removing a ball grid array mounted on a printed wiring board, characterized in that a heater block is raised according to the detection of the displacement amount.

(Supplementary Note 10) A method of removing a ball grid array mounted on a printed wiring board, comprising a spring for urging the ball grid array in a direction away from the printed wiring board under the main body of the ball grid array. And inserting the heater block into contact with the main body of the ball grid array to heat the main body, sense a melting temperature of the solder ball with a temperature sensor, and raise the heater block in response to the sensing of the melting temperature. A method for removing a ball grid array mounted on a printed wiring board, the method comprising:

[0053]

According to the present invention, the following effects can be obtained.

(1) Since the electronic components mounted around the printed wiring board and BGA are not heated, thermal damage to them can be suppressed to a minimum.
Repair work can be performed without impairing the reliability of the printed wiring board assembly.

(2) Since a plurality of BGAs can be removed at one time, the efficiency of repair work can be greatly improved.

(3) The BGA can be removed in a very short time, and the quality of repair work can be stabilized.

[Brief description of drawings]

FIG. 1 is a perspective view of a solder ball removing device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a solder jet state.

FIG. 3 is a cross-sectional view showing a jet flow stopped state.

FIG. 4 is a schematic configuration diagram of a second embodiment of the present invention.

FIG. 5 is a view showing a leaf spring and its action.

FIG. 6 is a schematic configuration diagram of a third embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a fourth embodiment of the present invention.

[Explanation of symbols]

4 container (solder device) 6 jigs 8 Solder jet nozzle 10 printed wiring board 12 BGA 16 Jet motor 18 Jet height adjustment knob 20 timer 22 Thermometer 24 molten solder 26 solder balls

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Claims (5)

[Claims] 1. A method of removing a ball grid array mounted on a printed wiring board, the printed wiring board having a ball grid array mounting surface facing downward so that the ball grid array is positioned in a solder jet nozzle. A method for removing a ball grid array mounted on a printed wiring board, characterized in that the molten solder in the solder jet nozzle is placed in contact with the main body of the ball grid array. 2. A device for removing a ball grid array mounted on a printed wiring board, the container containing molten solder and having an opening on the upper surface for inserting the ball grid array from above, and the opening. A device for removing a ball grid array mounted on a printed wiring board, comprising: a solder jet means for supplying molten solder into the inside. 3. A method for removing a ball grid array mounted on a printed wiring board, wherein a spring for biasing the ball grid array in a direction away from the printed wiring board is inserted under a main body of the ball grid array. A method for removing a ball grid array mounted on a printed wiring board, characterized in that a main part of the ball grid array is heated by a light beam heating device in a non-contact manner. 4. A method for removing a ball grid array mounted on a printed wiring board, wherein a spring for biasing the ball grid array in a direction away from the printed wiring board is inserted under a main body of the ball grid array. A heater block is brought into contact with the main body of the ball grid array to heat the main body, and the displacement amount of the heater block that descends when the solder balls are melted is sensed, and the heater block is detected according to the sensed displacement amount. A method for removing a ball grid array mounted on a printed wiring board, the method comprising: raising. 5. A method for removing a ball grid array mounted on a printed wiring board, wherein a spring for urging the ball grid array in a direction away from the printed wiring board is inserted under a main body of the ball grid array. A heater block is brought into contact with the main body of the ball grid array to heat the main body, a melting temperature of the solder ball is sensed by a temperature sensor, and the heater block is raised in response to the sensing of the melting temperature. A method for removing a ball grid array mounted on a characteristic printed wiring board.