¿ has soldado encapsulados BGA ? Yo tengo, por aquí unos cuantos DSP, en PBGA, y de momento no se como soldarlos.
Todo lo que tengo, son estas recomendaciones de Analog, de las que deduzco, que emplean flux, pasta de soldar e infrarrojos, pero a nivel casero no se como meterle mano a los bichos, sin cargármelos, y aunque sean samples, es material caro.
Surface Mount Assembly Recommendations for Plastic Ball Grid Array (PBGA) Packages Motherboard design and assembly recommendations:
1.. Capture pad/capture pad opening on customer's board should equal the solder mask opening OR ball pad size on the processor - whichever is smaller. 2.. Dimensions for the solder mask opening and ball pad size for some of ADI's DSPs in a BGA package are given below: *Solder Mask Defined (SMD) **Non-Solder Mask Defined (NSMD) 3.. Ball pad size may vary depending on the solder mask registration tolerance (this variance can be substantial between dry film/liquid apply, method of application and thickness). 4.. Ball pad finish can be copper with a protective anti-oxident chemical coat such as Entek, gold (electrolytic or electroless), or HASL (hot air solder leveling). 5.. Suitable solder pastes for screening are eutectic 63/37:SnPb, 60/40:SnPb, or 62/36/2:SnPbAg. 6.. Recommend a no-clean/low residue flux. 7.. A .008" screened solder paste height is recommended, but even .004" will be successful as PBGA is not terribly sensitive to paste height/volume. Generally, the paste height is determined by the screening/assembly of fine pitch components on the motherboard in the same pass. Solder paste particle size is also determined by need for assembly of fine pitch components. 8.. In the case of the SHARC PBGA, a group of balls in the center of the ball grid are designated as "thermal balls" in addition to their electrical purpose. The application board should allow for a low thermal resistance path from the thermal balls to a plane in the board. This is typically accomplished with a grid of vias that are also used to make the electrical connection for the thermal balls. Any plane used for thermal dissipation should be designed to be a min of 2oz copper to increase thermal conductivity away from the PBGA. This configuration acts as a thermal heat spreader and can significantly improve the thermal performance of the design. 9.. Component pick and place. PBGA are picked from Jedec-specified shipping trays. PBGA registration may be accomplished with edge or other package feature recognition, and mechanical centering. PBGA alignment markings and fiducials will be required to target and place the PBGA on the motherboard. 10.. IR convection reflow with nitrogen (and oxygen content control) is recommended especially with no-clean flux. 11.. Terpene solution cleaning is recommended if a flux that requires cleaning is used at reflow. 12.. Total solder ball collapse after PBGA assembly and final assembly to the motherboard will be approximately 25% with the solder mask/capture pad/solder ball dimensions given above. For example, a .76 mm solder ball will collapse to a final height of .56 mm after final reflow. 13.. PBGA may be assembled in a double-sided surface mount operation using adhesives (not useful with a full solder ball array) or relying on solder surface tension (dependent on BGA size/weight) during IR reflow. 14.. Monitor solder joint integrity/yields with shear test, x-ray and electrical test. 15.. Rework - bad units are replaced with new after hot air removal of bad units, solder wicking, and site re-dressing with solder paste. PBGA replacement procedures make a necessity of a component clearance zone of 0.20".