Successful welding BGA chip skills

Successful welding BGA chip skills

1.BGA chip removal

Do work of protective devices and in removing BGA IC, to observe whether the impact of the peripheral

component. Some of the phone's font, temporary storage, CPU* was very close. In the demolition of the

welding, can be placed in the vicinity of the IC into the cotton ball. Many plastics amplifier, soft package

of font resistant high temperature, blowing welding temperature should not be too high, otherwise, it is

easy to blow them bad.

In the above to be remove IC into the appropriate amount of flux, and try to blow into the IC at the

bottom, such Lenz help chip solder joints evenly melt.

Regulation of hot air gun temperature and wind, temperature is generally 3-4 file, wind 2-3 files, wind in

the mouth about 3cm above the chip mobile heating, until the chip under the solder melts completely,

with a pair of tweezers pick up the entire chip. Note: when heating IC to blow IC four weeks, do not blow

IC in the middle, otherwise easy to blow IC uplift, heating time is not too long, otherwise the circuit board

blowing bubbles.

BGA chip is taken off, the pads of the chip and board have more than tin, at this time, on the circuit board

and plenty of lead-free solder paste, with electric iron in excess solder removed and appropriate tin make

circuit board each weld legs are smooth and rounded, and then days that the water will wash the flux of

the chip and board, in addition to solder to special care, otherwise it will scratch pad above the green paint

or the welding disc shedding.

2.Tin plant

Fixing method for BGA IC has a variety of, described below two practical and convenient method:

stick paper label fixation: the IC is aligned with the planting of tinplate hole, label stickers for the IC

and transplantation of tin plate is firmly attached, IC alignment, the implanted tin by hand or tweezers

to prison does not move, then the other hand scraping slurry tin.

In IC pad below napkin fixation: in IC pad below several layers of paper towel, then the graft tin plate hole

and the IC foot alignment on, by hand or tweezers press down firmly implanted tin plate, and then blow

the solder paste.

Upper tin pulp. If solder paste is too thin, blowing welding is easy to boil lead to difficult for the ball, so

tin slurry is doing better, as long as not doing hair hard block can be, if it is too thin, available for napkin

paper pressure dry. Usually you can pick some solder paste on the solder paste on the inner cover, and

let it dry. With a flat blade knife pick amount of solder paste to planted on a tin plate, forced down

scraping, scraping edge pressure, solder paste evenly fill tinplate planting holes in.

Hot air gun wind tune as small as 2 stalls, shaking the wind mouth to plant tin tin slurry to make uniform

heating slowly, slowly melting. When saw the planting of tinplate individual holes have solder ball

formation, indicating that the temperature has been put in place, when should raise the air gun, avoid the

temperature continues to rise. Excessive temperature can make the tin slurry intense boiling, resulting in

the failure of tin tin. Serious damage to the IC. If the winds of the welding success and found some solder

ball flood is not uniform, and even individual no tin, first with a scraper along the graft tinplate surface

will have large solder ball of the exposed part of the flattened, and then sweep knife the solder ball too

full of solder paste and missing foot hole, and then use a hot-air gun to blow a can. If the ball is not

uniform water, repeat the above operation until the ideal state. Replanting, must be planted tin cleaning

getters, dry. Take and tin plate, hot tip tweezers in IC four angle downward pressure, so it is easy to

remove too.

3.BGA chip installation

The BGA IC weld legs that coated on one side with the right amount of solder paste, hot air gun

temperature transferred to 2nd gear gently blowing, solder paste evenly distributed on the surface

of the IC. To locate the IC solder for welding preparation. Then the temperature of hot air gun to

the 3 gear, first heating board, blowing molten flux. The graft good solder BGA IC according to

removing before the position into the circuit board, at the same time, by hand or tweezers will IC

around mobile and gently pressed, then you can feel the welded on the two sides of the foot of

the contact. After the alignment, because prior to the IC feet painted a little help paste, there is a

certain stickiness, IC will not move. If the position is partial, to re position.

After the IC BGA is positioned, it can be welded. And when planting a solder ball, adjustment of hot air

gun to fit the air volume and temperature, let the wind mouth of the central alignment of the central

position of the IC, slowly heating. When IC sees a sinking around to help paste overflow, that has solder

and solder joint fusion on the circuit board together. At this time can be gently shaking the hot air gun

so that the heating uniformity, due to the role of surface tension. IC BGA and line plate of the solder

joints between the automatic alignment positioning, attention in the heating process, do not force the

BGA, otherwise it will make the solder spill, extremely easy to cause off and short circuit. After the

welding is finished, the water will be cleaned by the water.

4.Disassembly method of BGA chip with glue

At present, many brands of mobile phone IC BGA are filled with sealing glue, more difficult to remove,

for this type of IC to remove the glue. Below to do a detailed introduction.

For Motorola sealing glue, the market has many brands of hydrosol can be conveniently to glue, after

many experiments found V998 CPU use banana water immersion to sizing effect is better, generally

soak 3-4 hours, sealing glue is easy to get rid of the. Note: V998 is the mobile phone before immersion

must remove the font, or font will be damaged. Because 998 font is a soft package BGA, not with

banana water, days that water or solution soaked in glue, glue in the solvent of soft package BGA font

have strong resistance to corrosion, the rubber expansion lead to scrap font. Of course, if you do not

dissolve the glue, can also be directly removed, Motorola's sealing glue is low temperature, easy to

soften, and the CPU is relatively high temperature, as long as the attention method, can be successfully

removed.

The wind speed and temperature of the hot air gun is transferred to the appropriate location

(the general air volume 3, 4 heat, can be adjusted according to different brands of hot air gun)

The hot air in the mobile CPU 5cm above the blowing, after about half a minute, with a small blade from

the CPU then anchor more in the direction of the start, general from the first leg, that is, * register above

began to pry, pay attention to hot air can not stop.

CPU removed, then is in addition to the glue, using a hot-air gun while blowing, Yili carefully with a knife

slowly a bit of a blow, until the welding plate clean so far.

NOKIA mobile phone at the end of the first special injection molding, there is no better way to fall, when

it is time to pay attention to the operation skills:

The fixed board, adjust the temperature of hot air gun between 270 DEG to 300 DEG C, and adjust air

quantity, with blowing shift resistive and capacitive components shall prevail, to the demolition of the IC

sealing glue preheating for about 20 seconds, then move air gun, machine plate cools preheating,

preheat 3 times, preheating of each to join the heavy oil flux to oil into the welding disc play a protective

role.

The hot-air gun temperature transferred to 350 DEG C to 400 DEG C, to IC heating, while the heat while

with tweezers light pressure IC, when see Xizhu squeezed out from the sealing glue, they can from a less

elements with forceps tip of the edge sealing glue to pick holes in and let the solder flow out, remember

this when still or stop put oil flux.

Apart from the IC, when see IC following no solder emerge, with hook fine tipped tweezers into risk under

the tin of IC, gently pick detachable the.

Clean sealing glue, most of the IC removed, sealing glue in the motherboard, put the tin point on the

motherboard first and foremost on flux, with a soldering iron to glue sealing solder sucking, smoking

more than a few times, can clearly see at the bottom of the light of the welding disc so far, the main

role is completely let solder joint and sealing glue separation. Wind temperature regulating gun 270

DEG to 300 DEG C, between, on board glue sealing heating, this time sealing glue is basically from the

pads, spotted solder and solder joint between a safe place use tweezers to pick, pick the efforts to

control, if plot right to pick a can take a large piece. For IC sealing glue cleared slowly is not the same,

first clean the IC, then in the IC is glued on the back of the double-sided adhesive, express it fixed in

the demolition of soldering station, between the temperature of the air gun is transferred to 270 DEG

to 300 DEG C, and put the soldering flux, heating and sealing glue, with a pair of tweezers a pick can

clearance.