1、 ENGINEERING MATERIAL SPECIFICATION Date Action Revisions 2012 07 25 N-Status No replacement A. Wedepohl, NA 2005 02 09 Revised Inserted 3.0; Deleted 3.1, 3.2, 3.7, 3.8, 4 1996 08 05 Activated M. Trace Copyright 2012, Ford Global Technologies, LLC Page 1 of 4 SOLDER PASTE (62 Tin/36 Lead/2 Silver, R
2、MA NOT FOR NEW DESIGN WSS-M11A44-A5 Flux, No-Clean, Stencil Printable) 1. SCOPE The material defined by this specification is a RMA 62 Sn/36 Pb/2 Ag solder paste. This solder paste is a homogeneous suspension of a prealloyed solder powder in a specially formulated screening and fluxing vehicle syste
3、m. 2. APPLICATION This specification was released as a conductive material used as a printable solder for surface mount connections and other applications. This solder paste was designed to be stencil printed onto printed circuit substrates and reflowed using either convection or infrared soldering.
4、 3. REQUIREMENTS This solder paste is a homogeneous suspension of a prealloyed solder powder in a specially formulated fluxing vehicle. All qualification testing shall be done at 25 +/- 2 C and 50 +/- 3% relative humidity, unless otherwise specified. 3.0 STANDARD REQUIREMENTS FOR PRODUCTION MATERIAL
5、S Material suppliers and part producers must conform to the Companys Standard Requirements For Production Materials (WSS-M99P1111-A). 3.3 COMPOSITION (IPC-SP-819, para 4.4, 50 gram sample required) Solder Metal, weight % 89.5 - 90.5 Vehicle Balance 3.3.1 Solder Metal Composition, Atomic Percent (AST
6、M B32/QQ-S-571F, class 1 impurity levels) Tin 61.5 - 62.5 Silver 1.8 - 2.2 Zinc 0.005 max Antimony 0.50 max Bismuth 0.10 max Copper 0.08 max Iron 0.02 max Aluminum 0.005 max Cadmium 0.005 max Other Elements 0.08 max Lead Remainder ENGINEERING MATERIAL SPECIFICATION WSS-M11A44-A5 Copyright 2012, Ford
7、 Global Technologies, LLC Page 2 of 4 3.3.2 Vehicle Composition, weight percent (IPC-SF-818, para 4.4.2.2, IPC-TM-650, para 2.3.34) Flux, % 59.0 min Solvent Balance 3.4 INDIVIDUAL COMPONENT PROPERTIES 3.4.1 SOLDER POWDER (Powder sample prior to mixing) 3.4.1.1 Particle Size Type 3 (IPC-SP-819, para
8、3.2.2) % of Sample by Weight - Nominal Sizes Less than 1% larger than 45 microns 80% minimum between 45 - 20 microns 10% maximum less than 20 microns 3.4.1.2 Particle Shape Spherical; (IPC-SP-819, para 3.2.3) Ratio = 1 - 1.5 3.4.2 FLUX VEHICLE (Flux sample prior to mixing) 3.4.2.1 Copper Mirror No c
9、omplete (IPC-TM-650, para 2.3.32) copper removal 3.4.2.2 Halide Content, max 500 ppm of (IPC-TM-650, para 2.3.35) vehicle comp. 3.5 VISCOSITY, mPa.s (IPC-TM-650, para 2.4.34.3, spiral pump viscometer, 25 +/- 0.25 C) 5 RPM (6 minutes) 2650 - 3800 10 RPM (1 minute) 1650 - 2450 15 RPM (1 minute) 1250 -
10、 1900 20 RPM (1 minute) 1000 - 1650 30 RPM (1 minute) 800 - 1300 3.6 SHELF LIFE, min 4 months Store an unopened container of solder paste at 5 +/- 5 C for the specified shelf life time period. The solder paste shall meet the viscosity requirements per para 3.5 of this specification. Shelf life is ba
11、sed on date of manufacture. The solder paste is to be delivered within one month of the date of manufacture. ENGINEERING MATERIAL SPECIFICATION WSS-M11A44-A5 Copyright 2012, Ford Global Technologies, LLC Page 3 of 4 5. GENERAL INFORMATION The information given below is provided for clarification and
12、 assistance in meeting the requirements of this specification. Contact for questions concerning Engineering Material Specifications. 5.1 If the material contains a rosin based flux, GC spectra of the extracted flux are required. 5.1.1 Extraction Method (a) Extract 2.0 g of paste with 3.0 mL of 50%
13、isopropanol/50% toluene solution. (b) Mix well and then use centrifuge to separate the metal particles from the liquid portion. (c) Collect liquid portion with pipette and save for GC sample preparation. 5.1.2 GC Sample Preparation (a) Pipet 50 microliters of the extracted flux mixture and dispense
14、into a GC sample vial. (b) To the sample vial, add 1 ampul Sylon BFT.* *The full name of Sylon BFT is Bis (trimethylsilyl) trifluoroacetamide (BSTFA)/ trimethylchlorosilane (TMCS). Sylon BFT must be stored in a refrigerator (shelf life - 1 year). It may be obtained in ampul form from: Supelco, Inc.
15、Supelco Park Bellefonte, PA 16823-0048 (c) Allow the mixture to stand for 5 minutes, then add 1.0 mL pyridine, and seal the vial. The mixture is ready to be injected into the gas chromatograph. 5.1.3 Equipment Parameters for Gas Chromatograph Column: DB-5 column, 0.25 mm ID, 0.25 um film, 30 m long
16、Colume Flow Rate: 1 mL/minute, 1:80 split ratio Sample Injection Quantity: 1.0 microliter Injector Temperature: 260 C Detector (FID) Temperature: 260 C Air Flow Rate: 400 mL/minute H2 Flow Rate: 32 mL/minute He Makeup Flow Rate: 30 mL/minute Temperature Profile: Hold the temperature at 70 C for 4 mi
17、nutes, ramp to 260 C at 10 C/minute, and hold on 260 C for 17 minutes. Total run time is 40 minutes. 5.2 If the material contains a polymer based flux, IR spectra of the extracted flux are required. Extract the paste with acetone and collect the liquid portion. The extracted flux is to be applied di
18、rectly to the KBr window. ENGINEERING MATERIAL SPECIFICATION WSS-M11A44-A5 Copyright 2012, Ford Global Technologies, LLC Page 4 of 4 5.3 Physical Properties 5.3.1 Solidus and Liquidus (ASTM E 793, solidus and liquidus are points at which the downward and upward slope tangents cross baseline, respectively) Solidus 179 C Liquidus 179 to 189 C
