1、 J-STD-002C Solderability Tests for Component Leads, Terminations, Lugs, Terminals and Wires 3rdWorking Draft February 2004 J-STD-002C 3rdWorking Draft February 2004 2 1 SCOPE 1.1 Scope This standard prescribes test methods, defect definitions, acceptance criteria, and illustrations for assessing th
2、e solderability of electronic component leads, terminations, solid wire, stranded wire, lugs, and tabs. This standard is intended for use by both vendor and user. 1.2 Purpose Solderability evaluations are made to verify that the solderability of component leads and terminations meets the requirement
3、s established in this standard and that subsequent storage has had no adverse effect on the ability to solder components to an interconnecting substrate. Determination of solderability can be made at the time of manufacture, at receipt of the components by the user, or just before assembly and solde
4、ring. The resistance to dissolution of metallization determination is made to verify that metallized terminations will remain intact throughout the assembly soldering processes. 1.3 Method Classification This standard describes methods by which component leads or terminations may be evaluated for so
5、lderability. Test A, Test B, or Test C and Test D, unless otherwise agreed upon between vendor and user, are to be used for each application as a default. 1.3.1 Tests with Established Accept/Reject Criteria Test A Solder Bath/Dip and Look Test (Leaded Components and Stranded Wire) Test B Solder Bath
6、/Dip and Look Test (Leadless Components) Test C Wrapped Wire Test (Lugs, Tabs, Hooked Leads, and Turrets) Test D Resistance to Dissolution/Dewetting of Metallization Test Test S Surface Mount Process Simulation Test 1.3.2 Test without Established Accept/Reject Criteria Test E Wetting Balance Test (L
7、eaded Components) Test F Wetting Balance Test (Leadless Components) These methods are included for evaluation purposes only. Data collected should be submitted to the IPC Wetting Balance Task Group for correlation and analysis. 1.4 Coating Durability The following are guidelines for determining the
8、needed level of steam conditioning category assurance (see Table 1-1). The user and vendor need to agree on the coating durability requirements. If this is not provided, Coating Durability Category 3 becomes the default condition for tin and tin/lead finishes. Category 1 Minimum Coating Durability I
9、ntended for surfaces that will be soldered within a short period of time (e.g., up to six months) from the time of testing and are likely to experience a minimum of thermal exposures before soldering (see 5.8). Category 2 Typical Coating Durability (for nontin and nontin-lead finishes) Intended for
10、surfaces finished with other than Sn or Sn/Pb coatings that will be soldered after an extended time from the time of testing and which may see limited thermal exposures before soldering (see 5.8). Category 3 Typical Coating Durability (default for tin and tin-lead finishes) Intended for surfaces fin
11、ished with Sn or Sn/Pb coatings that will be soldered after an extended storage (e.g., greater than four months) from the time of testing and/or which see multiple thermal exposures before soldering (see 5.8). Table 1-1 Steam Conditioning Categories for Component Leads and Terminations Category 1 Ca
12、tegory 2 Category 3 No Steam Conditioning Requirements 1 Hour 5 min. Steam Conditioning 8 hours 15 min. Steam Conditioning J-STD-002C 3rdWorking Draft February 2004 3 1.5 Referee Verification Solder Dip for Tests A, B, C When the dipped portion of the termination exhibits anomalies such as surface r
13、oughness, or dross, or anomalies that may have been induced by improper solder dipping, a referee verification solder dip of the suspect anomaly may be necessary. Upon reinspection if the suspect anomaly has been removed, the anomaly will have been verified as a nonrejectable cosmetic surface defect
14、. If the anomaly persists, regardless of area, it shall be classified a rejectable solderability defect. This procedure may only be used on one component per lot. Continuous need of procedure is an indication of either improper testing procedure, examination interpretation, or of poor component qual
15、ity. 1.6 Limitation This standard shall not be construed as a production procedure for the pretinning of leads and terminations. 1.7 Contractual Agreement In cases where the stated test parameters are inappropriate or insufficient, alternative parameters may be agreed upon between vendor and user. 2
16、 APPLICABLE DOCUMENTS The following documents of the issue currently in effect form a part of this standard to the extent specified herein. 2.1 Industry 2.1.1 IPC IPC-T-50 Terms and Definitions IPC-CS-70 Guidelines for Chemical Handling Safety in Printed Board Manufacturing IPC-TR-464 Accelerated Ag
17、ing for Solderability Evaluations and Addendum J-STD-004 Requirements For Soldering Fluxes J-STD-005 Requirements for Soldering Pastes J-STD-006 Requirements for Electronic Grade Solder Alloys and Fluxed and Non-Fluxed Solid Solder for Electronic Soldering Applications 2.2 Government 2.2.2 Federal (
18、CID) A-A-59551 Wire, Electrical, Copper (Uninsulated) 3 REQUIREMENTS 3.1 Terms and Definitions The definition of terms shall be in accordance with IPC-T-50. Terms that have been repeated from IPC-T-50 for convenience are indicated by an asterisk (*). Dewetting* A condition that results when molten s
19、older coats a surface and then recedes to leave irregularly-shaped mounds of solder that are separated by areas that are covered with a thin film of solder and with the basis metal not exposed. Dissolution Of Termination Metallization (Leaching) Area on the component termination where metallization
20、is lost/ removed from the basis/substrate material after immersion in molten solder. Equilibrium Wetting The degree of wetting in which the forces of wetting are in equilibrium with the forces of gravity. The visible indication of this is when the wetting balance curve flattens out and approaches ze
21、ro slope (see Figure 4-7). Nonwetting, Solder* The partial adherence of molten solder to a surface that it has contacted; basis metal remains exposed. Pinhole* An imperfection in the form of a small hole that penetrates entirely through a layer of material. Solderability* The ability of a metal to b
22、e wetted by molten solder. Solder Connection Pinhole* A small hole that penetrates from the surface of a solder connection to a void of indeterminate size within the solder connection. Wetting, Solder* The formation of a relatively uniform, smooth, unbroken, and adherent film of solder to a basis me
23、tal. J-STD-002C 3rdWorking Draft February 2004 4 3.2 Materials All chemicals shall be of commercial grade or better. Fresh solvents shall be used as often as is necessary to preclude contamination. 3.2.1 Solder Solder composition shall be Sn60/Pb40 or Sn63/Pb37 per J-STD-006. The composition of the
24、solder, including contamination levels, shall be maintained during testing per 3.5.2. The composition of the solder paste to be used in Test S shall be Sn60/Pb40 or Sn63/Pb37 per J-STD-005, mesh size of -325/+500, flux type ROL1 (formerly designated RMA). The solder paste shall meet the storage and
25、shelf life requirements of the manufacturers specification. 3.2.2 Flux The flux for all solderability tests shall be a standard activated rosin flux (Type ROL1 per J-STD-004) having a composition of 25% 0.5% by weight of colophony and 0.15% 0.01% by weight diethylammonium Hydrochloride (CAS 660-68-4
26、), in 74.85% 0.5% by weight of isopropyl alcohol. The specific gravity of the standard activated rosin flux shall be 0.843 0.005 at 25 2C 77 3.6F. The flux to be used in preparing the standard wire for test C shall conform to J-STD-004, Type ROL1. This flux shall not be used in performing the solder
27、ability tests for any of the methods herein. 3.2.2.1 Flux Maintenance The flux shall be covered when not in use and discarded after eight hours or the flux shall be maintained to a specific gravity of between 0.842 and 0.846 at 25 2C 77 3.6F and discarded after one week of use. 3.2.3 Flux Removal Ma
28、terial used for cleaning flux from leads and terminations before solderability evaluations shall be capable of removing visible flux residues (see 5.5). The cleaned surface shall exhibit no mechanical damage. 3.2.4 Standard Copper Wrapping Wire The standard wrapping wire specified in 4.2.3.2.1 shall
29、 be fabricated from type S, soft or drawn and annealed, uncoated in accordance with (CID) A-A-59551. The nominal diameter of the wrapping wire shall be 0.6 mm 0.023 in. The preparation of the wrapping wire shall be as follows: a. Straighten and cut wire into convenient lengths (50 mm 1.9 in minimum)
30、. b. Degrease by immersion in an appropriate cleaner (e.g., isopropyl alcohol) for two minutes. c. Clean in fluoroboric acid 10% HBF (by volume), in water, for five minutes at room temperature with agitation. Use caution in handling. d. Rinse acid off as follows: 1. Two nonheated water rinses (deion
31、ized or distilled). 2. Two isopropyl alcohol rinses. 3. Air dry. e. Immerse in flux J-STD-004, Type ROL1. f. Dip in molten solder for five seconds at 245 5C 473 9F. 3.2.4.1 To remove or dissolve the residual flux, wash or rinse per 3.2.3. 3.2.4.2 Standard wrapping wire will be stored in a clean, cov
32、ered container if not used immediately. The usable life of the standard wrapping wire shall not exceed 30 days after coating. 3.2.5 The water to be used for steam conditioning purposes shall be distilled or deionized. 3.3 Equipment The following equipment applies to more than one of the solderabilit
33、y test methods shown in this standard. Equipment that is specific to any of the test methods is described in the specific Clause 4 paragraphs detailing the method. 3.3.1 Steam Conditioning Apparatus The steam conditioning chamber shall be constructed of noncorrodible materials such as borosilicate g
34、lass, quartz glass, stainless steel or ptfe. The specimen holder shall be nonreactive to prevent galvanic corrosion. The container should be insulated. The steam temperature at the conditioning level shall be maintained per the requirements of Table 3-1. J-STD-002C 3rdWorking Draft February 2004 5 T
35、able 3-1 Steam Temperature Requirements Altitude Average Local Boiling Point C Steam Temperature Limits C 0-305 m 100 93 3 305-610 m 99 92 3 610-914 m 98 91 3 914-1219 m 97 90 3 1219-1524 m 96 89 3 1524-1829 m 95 88 3 A safe means to prevent excessive pressure and a means of maintaining adequate wat
36、er level shall be provided. Neither shall cause the vapor to cool below the specified temperature. Condensate shall drip freely back to the water. Care should be taken to minimize contact between the condensate and the specimens. 3.3.2 Solder Vessel A thermostatically controlled static solder vessel
37、 shall be used for all applicable tests. The solder vessel shall be of adequate dimensions to accommodate the specimens and contain sufficient solder to maintain the solder temperature during testing, and to prevent exceeding the contamination levels (see 3.5.1 and 3.5.2). A minimum of 750 grams of
38、solder should be used. 3.3.3 Optical Inspection Equipment All test methods requiring visual inspection shall use microscope(s) capable of magnification 10X (see individual test methods), equipped with reticles, or equivalent, for measurement. An example of a reticle is shown in Figure 3-1. Shadowles
39、s lighting shall be suitable for proper inspection. Figure 3-1 Example Reticle 3.3.4 Dipping Equipment Solder dipping devices shall be mechanical/electro-mechanical and capable of controlling the immersion/emersion rates, dwell time and immersion depth as specified in 4.2.1 to 4.3.3. Sample holding
40、fixtures shall be designed to avoid trapping any excess flux in the fixture and to minimize heat loss and assure reproducibility of test results. 3.3.5 Timing Equipment Timing equipment shall be automated, where applicable, and accurate to the limits of the test method. 3.4 Preparation for Testing 3
41、.4.1 Specimen Preparation and Surface Condition All component leads or terminations shall be tested in the condition that they would normally be in at the time of assembly soldering. The specimen surfaces to be tested shall be handled in such a manner as to not cause contamination, nor shall the lea
42、ds or terminations being tested be wiped, cleaned, scraped or abraded. Special preparation of leads or terminations, such as bending or reorientation before test, shall be specified in the applicable procurement document. If the insulation on stranded wires must be removed, it shall be done in a man
43、ner so as not to loosen or damage the individual strands of the wire. 3.4.1.1 Steam Conditioning Categories The user shall specify to the vendor, as part of the purchase agreement, the required coating durability (see 1.4). Accelerated steam conditioning shall be performed per Table 1-1. Solderabili
44、ty testing shall be performed per Table 3-2. J-STD-002C 3rdWorking Draft February 2004 6 Table 3-2 Solderability Test Selection Component Type Surface Mount Test Method Wrapped Wire Through-Hole Mount Leadless J-Lead Gull Wing Tests with Established Accept/Reject Criteria A Dip three (3) seconds. A sample calculation for a 132 I/O QFP is shown below. V = Total Volume per side (33 leads) = 0.85 mm3Maximum Theoretical Force = 18.41 mN Therefore the area for a part in the Set A criteria is: AA = (0.5 X 3.0 X 18.41) - (2.0 X 0.08 X 0.85) = 27.62 - 0.136 = 27.48 mN seconds
