APPLICATION NOTE | AN:303 Assembly Guideline for Picor Cool-Power 10x14mm LGA/BGA Package ContentsPage Description Cool-Power SiP Details1 This application note provides information and recommendations relevant to handling procedures and assembly with the Cool-Power 10x14 Land Grid Array (LGA) and Ball Grid Array (BGA) packages. Receiving PCB Pad Cool-Power SiP Details Description1 1 Receiving PCB Board2 Solder-Paste Stencil Assembly and Cleaning 2 2 n n n n Refer to 10x14mm Package Drawing All pads are SMD (solder mask defined) All pads are Ni/Au finish Maximum body temperature is 245°C LGA Inspection2 n All pads are 0.55mm x 0.55mm (exposed copper area) n Package volume is 350mm3 n Package weight is 0.8 grams (typical) Rework and Removal 2 BGA Mositure Sensitivity Level (MSL) Assembly Re-flow Guidelines 2 3 n All solder bumps are .64mm diameter n Package volume is 390mm3 n Package weight is 1.1 grams Receiving PCB Pad n n n n OSP, ENIG, ENEPIG, or NI/Au finish recommended Pads within planes/polygons are SMD only, with 0.55 x 0.55mm final size soldermask openings Signal pads can be either SMD or NSMD (non-soldermask defined) SMD signal pads should have a minimum copper pad of 0.65 x 0.65mm, with a soldermask opening of 0.55 x 0.55mm LGA n All pads have exposed copper area of 0.55 x 0.55mm n NSMD should have a copper defined pad of 0.55mm x 0.55mm, with a soldermask opening of 0.65 x 0.65mm BGA n All pads have exposed copper area of 0.45mm diameter pad opening n NSMD should have a copper defined pad of 0.45mm diameter Cu defined/SM opening of .6mm AN:303 vicorpower.com Applications Engineering: 800 927.9474 Page 1 Receiving PCB Board (LGA/BGA) n Board should be made from FR4 – Tg 170°C or higher rated material n Board should have a minimum of four layers of 2oz copper n Planes/Polygons underneath part should not have thermal reliefs around SMD pads or vias n Thermal vias are recommended, please refer to specific product data sheets for information n Silkscreen under the SiP is not recommended Solder-Paste Stencil LGA n Recommended stencil openings for pads is 0.45 x 0.45mm (80% aperture) using a 5mil or 6mil stencil thickness n Aperture size should not exceed 95% to ensure paste is not in the solder mask area BGA n Recommended stencil openings are .40mm diameter(90% aperture)using a 4mil or 5mil stencil thickness n Flux can also be used using a 2mil thick stencil Assembly and Cleaning n n n n n n Handling and storage of SiPs per IPC 1601, JEDS625-B Pre-bake components based on component MSL rating prior to assembly (per IPC/JEDEC J-STD-020D.1) Pick and place should be from the center of the component Pb or Pb free (SAC305), low voiding solder paste such as AIM WS488, Kester 520A, or equivalent Aqueous clean using a saponifier or ultrasonic DI water spray for under SiP cleaning Inspection n X-ray inspection is recommended for solder joint inspection n Up to 25% area voiding per pad is acceptable Rework and Removal n Rework maximum temperature should not exceed 245°C (from Table 3). n Removed SiP should not be reused Moisture Sensitivity Level (MSL) n n n n n Components are baked and dry-packed before shipment. Components should remain in a dry vacuum bag during storage prior to assembly A MSL label is attached to the outside bag Within the bag is a humidity indicator card and desiccant Shelf life of the components sealed in the bag is 2 years at <40°C and <90% room humidity (RH) AN:303 vicorpower.com Applications Engineering: 800 927.9474 Page 2 Assembly Re-flow Guidelines (LGA/BGA) Table 1. Reflow Profile Recommendations (JEDEC/IPC J-STD-020D.1) [1] [2] 150°C Pre-heat temperature Max (Tsmax)150°C 200°C Pre-heat time (ts) from Tsmin to Tsmax Table 3. Pb-Free Process Peak reflow Temperature (TP)[3] Pb-Free Assembly Pre-heat temperature Min (Tsmin)100°C Sn-Pb Eutectic Process Peak reflow Temperature (TP)[3] Sn-Pb Eutectic Assembly Table 2. Profile Feature Ramp-up Rate (TL to TP) 60 – 120 seconds 60 – 120 seconds 3°C/second maximum 3°C/second maximum Liquidous temperature (TL)183°C Time (tL) maintained above TL 217°C 60 – 150 seconds 60 – 150 seconds Peak package body temperature (TP) See Table 2 See Table 3 Time (tP) within 5°C of peak temperature (TP) 20 seconds 20 seconds Ramp-down Rate (TP to TL) 6°C/second maximum 6°C/second maximum Time 25°C to TP 6 minutes maximum 8 minutes maximum Package Thickness Volume mm3 < 350 Volume mm3 ≥ 350 < 2.5 mm 235°C 220°C ≥ 2.5 mm 220°C 220°C Package Thickness Volume mm3 < 350 Volume mm3 350-2000 Volume mm3 ≥ 2000 < 1.6mm 260°C 260°C 260°C 1.6mm - 2.5mm 260°C 250°C 245°C > 2.5mm 260°C 245°C245°C Notes for Tables 1, 2 and 3 [1] All temperatures refer to the topside of the package, measured at the center of the package on the body’s surface. [2] Tolerance for TP is defined as a supplier’s minimum and a user’s maximum. [3] The package volume excludes the external terminals such as balls, bumps, lands, and leads. AN:303 vicorpower.com Applications Engineering: 800 927.9474 Page 3 Assembly Re-flow Guidelines (Cont.) Figure 1. Reflow Classification Profile (JEDEC/IPC J-STD-020D.1) Rev 1.3 06/16 vicorpower.com Applications Engineering: 800 927.9474 Page 4