Simple BGA Reballing

This instructable will use the solder preform process to teach you how to reball a plastic BGA in about 10 minutes or less. You will need:

1. Reflow source (reflow oven, hot air system, IR system)

2. Paste flux (water soluable is preferred)

3. Soldering iron w/blade tip

4. Braid/Wick

5. Kim wipes

6. Water and soft brush for cleaning

7. Inspection source

8. The correct preform based on the mechanical datasheet of the part being reballed

9. Device to be reballed

10. ESD wrist strap

Step 1: Deball the device

Apply water soluable paste flux using a syringe and smear with a gloved finger on the balls of the device. Using the proper blade tip and or temperature setting based on the alloy of the solder balls, remove solder balls. Use solder wick to remove remnant solder making sure pads are flat.Make sure to move the braid up and down not sweeping the base of the part which may scratch the mask or lift pads on the part.

Step 2: Clean the deballed part

Using isopropyl alcohol and non static inducing wipes clean off the flux residue from the bottom of the deballed part.

Step 3: Apply paste flux

Inspect the device to make sure that there is not scratched mask not lifted pads on the bottom of the device. Apply water soluable paste flux to the bottom of the part. Spread with a soft brush until uniform thickness is on the bottom of the part.

Step 4: Put preform ball side up

Place preform ball side up onto flat heat resistant surface like a flat ceramic plate. Make sure the preform lines up to the patterns on the device. Make sure you are attached the proper solder alloy solder balls on to the device.

Step 5: Carefully place device on top of preform

Carefully place the device on top of the BGA reballing preform making sure the pattern orientation is correct.

Step 6: Square up preform to device

Using angle brackets or other meas "square up" the preform to the BGA.

Step 7: Reflow

Place "sandwich" construction of the preform and device in to reflow oven or other heat source. Make sure the proper temperature settings are in place.

How to rework a BGA

This instructable will explaining the easiest possible way with the least sophisticated equipment on how to replace a BGA. This method requires the following:

1. New device to be placed (or previously reballed device)

2. StencilQuik(TM) stay in place stencil matching the pattern of the BGA

3. Solder paste

4. Miniature squeegee

5. Reflow source

6. Magnification system for inspection

This technique eliminates the need for a high end rework system. while an x-ray is not on this list (and by all rights should be)

Step 1: Clean the location

low charge-generating wipe, clean the area with isopropyl alcohol or other approved cleaner.

Step 2: Align and place the stencil

Using a low lint, After removing the backing from the rework stencil, start in a corner and slowly align and place the stencil aligning the apertures with the pads on the board.

Step 3: Apply pressure to activate adhesive

Apply pressure to the stencil surface on order to activate the adhesive.

Step 4: Squeegee solder paste into apertures

Using a micro squeegee slightly larger than the device squeegee solder paste in to the apertures. Use the correct solder alloy. Move the squeegee back/forth until all of the apertures are clean. Using a static free and lint free cloth wipe the surface and the extra solder paste from the stencil.

Step 5: Place the replacement device in the stencil apertures

Place the device in to the stencil apertures. You can tactically "feel" the solder balls as they fit in to the stencil apertures. Be careful to not apply too much downward pressure or you will "squeeze out" the solder paste. Make sure the orientation of the part is correct using the reference designator.

Step 6: Reflow and inspect

Using a low end reflow source follow the profile for the given solder alloy. This heart source can be lower end system. Inspect the solder balls to make sure that they are uniformly collapsed. The stencil also acts as a "band aid" for any damaged mask material.

BGA Reworking Full Professional Procedure

In order to perform proper BGA reworking you need the right tools and equipment for the job. Proper procedure and setup is crucial in order to achieve longevity in the repair.

Items needed:

BGA Rework Machine

Kingbo Flux

Kapton/ Aluminum Tape

Thermometer & Thermocouple


Step 1: Preparation
By prepping the board for rework you can eliminate the chances of:

Board flex

Popcorn

Delamination

Proper preparation is removing moisture from the board, many boards have a MSL or moisture sensitivity level. The safest way to remove moisture without having the proper data sheet is to bake the board at 80c for 24 hrs.

Ultrasonic cleaning can also be used to remove any contamination. Special cleaning solution is used which can restore a board to factory new condition.

Step 2: Support
A key ingredient in successful bga reworking is making sure the board is properly supported. If this step is skipped there is the risk that the board will bow or flex. Sometimes it is very obvious and other times it is hard to tell. A flexed board may contain damaged internal traces or lifted pads. This damage is not repairable.

You want to ensure that the board is stiff in all areas, so that when the board is heated it will not bend or move in any direction. The area around the chip being reworked should have extra support as it will reach extremely high temperatures and it is crucial that the board remains flat or solder bridges will occur causing shorts.

Many BGA rework machines include basic support systems. There are 3rd party board supports that can sometimes perform better than stock supports.

How to build a profile

How to create a lead free profile when starting using a new rework station, here's my procedure:

basically you want to run a preheat cycle with just the lower heater running, to do this program:

0.00/0/600
-0.01/0/0

(0.00 will be step on the pc410 and -0.01 will be end)

id personally set the lower temp to around 220, then with a stopwatch record the actual topside temp after each minute. The aim is to get the topside temp to 165-170 before your top heater kicks in. Once you have a time then that would be your first step. so if the stopwatch is at 5 minutes when your top heat reaches 165 and levels out then you can shut down the machine using the emergency stop and allow to cool. repeat this until you consistently hit the same topside temp. if youre machine takes 5 mins then step 1 would be:

0.00/0/300

once you have a base preheat profile you can then add the top heater steps. the aim of the top heater is purely to blast the end of the profile and finish off the work. ideally each top heater step should be no more than 15C step up and you want the starting top heater temp to be 190C.

so:

0.00/0/300
1.00/190/60
END

allow this to run and once the topside sv reaches 190 start the stopwatch again, the aim now is to time how long it takes for the pv to reach 190 and this will be your 2nd step dwell.

repeat this process for 200C, 210C and 225C and you should then have a complete profile which looks something like this:


0.00/0/300
1.00/190/20
1.00/200/20
1.00/210/20
1.00/225/20
-0.01/0/0

at that point you are now done with your lead free reflow/lift profile. when testing to ensure the chip is reaqdy for lift or whether properly reflowed we suggest nudging the side of the chip once topside temps are around 225, by nudge we mean the slightest nudge and you will see the gpu rock, the aim is to rock the gpu not move it. if the gpu rocks then you know the solder is fully melted and you have reached the point of reflow.


next step is to create a leaded reattach profile. Assuming you have the above steps sorted and you have a perfect lead free profile then its simple.

if your lead free profile is:

0.00/0/300
1.00/190/20
1.00/200/20
1.00/210/20
1.00/225/20
-0.01/0/0

simply remove the 210 and 225 steps and your profile will be:

0.00/0/300
1.00/190/20
1.00/200/20
-0.01/0/0

Hot Air Rework Station v.s Infrared BGA Rework Stations?

Hot air rework station actually can be divided in to hot air BGA rework station and hot air soldeting stations. 
The hot air rework station they say in this editorial is hot air BGA rework station.
How to class a BGA rework station (a hot air or infrared bga rework station ) is depending on the top heating heater. If the top heating heater makes use of hot air, they say it is hot air bga rework station such as ZM-R6200. If top heater makes use of infrared expertise, they say it is infrared BGA rework station
But what other the differences between them?
Infrared expertise are total new, and it comes in to market in recent years and it is taking increasingly promotion share.Because hot air bga rework stations some times may give uneven heat, and may cause surrounding parts shift or PCB deformation, technicians find another solution for it, that is using infrared expertise.
If customers require to ask which bga rework station is better? Infrared Stations or hot air bga rework station? This is hard to answer. Hot air ones is traditional, and they already be used for over 10 years in the market, and now it is take massive market share.
Infrared BGA Rework Stations use infrared ceramic heating plate, they give even heating without cause shift of other surrounding parts, but the infrared ceramic plate is with fixed size, sometimes you require to make use of high temperature tape to cover the surrounding area of the BGA chip. Actually, when use hot air bga rework station , it may come across same issue.
Usually speaking, hot air bga rework station is more comlicated than Infrared BGA rework station in structure and the cost is a tiny higher, . Because there’s plenty of cables in top hot air heater and with built-in cooling fan method. However hot air BGA rework stations are used with different hot air nozzles and these air nozzles can get replaced for different sizes of BGA chips and can be rotated in 360 degree which very simple for alignment with bga chips.

iphone 5s home button not working after screen replacement ?

The home button does not work now (touch id working fine) but when you press home button does not do anything.

BGA rework station :IR Vs Hot air

Infrared BGA rework station is more accurate and higher efficient than hot air gun in reworking, and what’s more you do not have to be that skillful.

Infrared rework station gives even heating distribution on component need to be reworked.

seldom leads to component shift and tilt for BGA, CSP components because there is no hot air flow during the reworking process.

Hot air rework station is a traditional bga rework tools, it mainly uses mature hot air heating system. 

Hot air rework station must be used with hot air nozzles with different sizes and structure, sometimes it may give uneven heating because the poor design hot air nozzles give uneven hot air flow, and temperature difference happens which lead to component shift or tilt especially for CSP or BGA component. 

Uneven heat of hot air rework station will not suitable for CSP component with bottom underfilled or lead free reworking.

SMT reflow oven

Problem 
"I'm new in this industry and need a little direction. I have a wide verity of SM parts on a board, top and bottom. The larger components have a very nice reflow, good shine. The 0402/0201's has a dull almost cold solder look. The boards function and work properly but I am not satisfied with is look.
I have a Heller 7 zone oven that allows me to make a profile to match the kester solder reflow profile. where should I go for more information to insure a good product?"

Answers FYI
1.1 Profile Solution to Cold Soldering Cause for Cold soldering The peak temp of reflow is too low. The preheating temp is too high and it takes too long Solution Lower the preheating temp and increase the peak temp in the reflow zone
1.2 Profile Solution to Solder Bridges Cause for Solder Bridges The viscosity of melting solder during reflow is high Solder paste collapse during preheating Solution Lower the preheating temp a little and increase the peak temperature
1.3 Profile Solution to Solder Balls Cause for Solder Balls Preheating has not been done properly

Small paste deposits have less flux thus less flux activity to enhance the wetting. So preheat needs to be as short as possible, ramp to spike if possible. Try not to ramp hold and spike - pending thermal delta on product can be made to ramp to spike ok without hold phase.
If Paste is T4 or higher, and non N2 reflow, issue is worse as higher metal surface area is involved togather with lower flux amount.
If can increase paste volume with stencil design can try and balance this out a bit.
If have access to N2 reflow this helps greatly as solder paste deposits get smaller.
Of course the solder paste flux has influence one vs another - better activity in smaller amounts , but always trade off - more active flux can be issue in post assembly pending product intended purposes etc

Regarding the issue you are having with 0402 and 0201 components can be caused by factors such as: 1) Wrong solder paste type. 2) Insufficient flux. 3) Wrong profile, etc.

BGA REWORK- IR OR HOT AIR CONVECTION ? IS THE BEST

1.which type of rework station is best compare to the IR or HOT air convection?
2.Which process plays best reliabilty on soldering after post soldering process?

For small boards simple components (low mass, dark colors, etc), IR can be of good help.
Forced hot air works much better and in a reliable way. According to the configuration (ie.high power bottom heaters, etc) you can remove/replace large and heavy components (ie. BGA, even CCGA 52.5 mm x 52.5 mm >150 grams)on a very thik board (> 3,5 mm)( we did it by DRS-24).
Hot air is best. IR takes longer and is affected by the color of the part.

FAQ :CPU bga reballing

I've got the gist of the procedure. Do correct me if I am missing anything?

1. Cover everything but the cpu socket with aluminum foil
2. Use pen type flux to flux the area around the cpu socket and let if flow between the socket and motherboard.
3. Use heat gun to heat the cpu socket to ~200^C.
4. .........
5. Profit!

Questions:

1. Won't the CPU Socket itself melt at 200C?

2. Won't the solder at the back of the motherboard melt?


"I've got the gist of the procedure"
Looks so to me as well. I'm just going to add a bit more details or tips if I have any on some of the steps. I don't think I have an exact step-by-step process, since there can be set-up and tool availability variations.


"1. Cover everything but the cpu socket with aluminum foil"
It's a good idea. But it's better to just put a "wall" of aluminum foil just a few centimeters around the CPU socket and not cover anything (except possibly capacitors, if there are any that are too close to the CPU socket).
Also, do something similar on the under side of the boards as well - at least if we are going to reflow from both the topside and the bottom side (more on that in a bit).


"2. Use pen type flux to flux the area around the cpu socket and let if flow between the socket and motherboard."
Good idea. But since there is great variation of fluxes, and they all perform differently, I would recommend you first put a little bit of that flux on the surface of a broken/junk motherboard and a piece of solder next to it. Then blast it with your heatgun and see what it does. Ideally, you'll want the solder ball to melt and the flux to still be active. Some fluxes (especially cheap liquid fluxes) will just boil/sizzle and leave a brown residue way before the solder melts - you don't want this! Such fluxes are only good for general soldering, but not for reflowing/reballing and BGA work.
One flux that I can recommend to you that is very decent for BGA work is Kingbo. If you can find smaller quantities so that you can find it cheaper (generally, it comes in 100g jars), then definitely get some. It's not like the 100g jars are overly expensive and you can use it for any type of solder work, but still something to keep in mind.


"3. Use heat gun to heat the cpu socket to ~200^C."
This appears to be a post-RoHS era motherboard, so it likely uses lead-free solder. In that case, you would need to get the solder up to at least 220C (around 230C is best, but don't exceed 250C as some components will not take the heat too well).
If you are using the bog-standard type-K thermocouple that came with your temperature meter (assuming you got one), then keep in mind that it will take some time before the thermocouple picks up with the board temperature. Generally, the larger the thermocouple, the slower it will respond to the heat changes. So by the time the board has reached 230C, you may as well have some areas reach 240C or higher if the thermocouple is big. Just keep that in mind.
Last, and most important, I would recommend you heat the board from both sides to avoid warping. The easiest way to do this is to put the board on a oven-type grill or some kind of metal screen and suspend that off the edge of a desk or table. This will give you access to both sides of the board. However, make sure the grill/screen is solid and won't warp from the heat or allow the board to warp from the heat (add aluminum foil balls as supports as needed around the CPU socket). Once you have that set up, start heating the board from the bottom. Make sure to move the heatgun nozzle around so that it doesn't create hot spots or end up overheating certain areas... At around 150C+ temperature near the CPU socket, you may stop the heating and proceed to adding flux around the CPU socket (but make sure you don't get any in the socket!). Putting flux on a hot board is better, because the heat will suck the flux under the socket. After this, go back to heating the board from the bottom. When it reaches around 180C, move to the top side and heat the CPU socket from above. Go all the way until at least 220C (as mentioned above). Once you do, hold the temperature there for about 10 seconds, then you can turn off the heat and let the board cool.

Alternatively, if you don't have a grill or metal screen to put the board on, then put the board on a flat surface and add aluminum balls as supports - especially around the CPU socket. This is done to prevent the motherboard from warping from the heat. The repeat the above procedure, but by only heating from the top side.


"1. Won't the CPU Socket itself melt at 200C?"
Shouldn't unless you heat it up way too much. It may become a bit more yellow, though.


"2. Won't the solder at the back of the motherboard melt?"
Yes, but that's a good thing. It means that the solder under the CPU socket has successfully melted as well (so higher chances of the reflow being successful).