1、 ENGINEERING MATERIAL SPECIFICATION Material Name Specification Number Date Action Changes 2014 06 11 N Status No replacement named. L. Sinclair, NA 1996 10 23 Revised Add 3.4.1.4, 3.6.2, 3.8.4; Rev. 3.8.7 R. Gordon 1996 08 05 Activated R. Gordon WP 3948-a Page 1 of 9 PRINTED CIRCUIT BOARDS, PTF, DO
2、UBLE SIDED, WSF-M22P5-A1 FLEXIBLE NOT TO BE USED FOR NEW DESIGN 1. SCOPE This specification defines the performance requirements for a double sided flexible circuit board with polymer thick film (PTF) conductors via connections. A double sided flexible circuit board is defined as a circuit board man
3、ufactured with two layers and is capable of being flexed 180 degrees without damage. 2. APPLICATION This specification was originally released as the performance requirements for flexible circuit boards to be used as the interconnect for electronic modules. 3. REQUIREMENTS 3.1 QUALITY SYSTEM REQUIRE
4、MENTS Material suppliers and part producers must conform to Quality System Requirements, QS-9000. Material specification requirements are to be used for initial qualification of materials. A Control Plan for ongoing production verification is required. This plan must be reviewed and approved by the
5、relevant Ford Materials activity and/or Ford Supplier Technical Assistance (STA) prior to production parts submission. Appropriate statistical tools must be used to analyze process/product data and assure consistent processing of the materials. Part producers using this material in their products, m
6、ust use Ford approved materials and must conform to a process control plan which has been approved by STA and/or the relevant Materials Activity. 3.2 INFRARED SPECTROPHOTOMETRY AND/OR THERMAL ANALYSIS Ford Motor Company, at its option, may conduct infrared and/or thermal analysis of material/parts s
7、upplied to this specification. The IR spectra and thermograms established for initial approval shall constitute the reference standard and shall be kept on file at the designated material laboratory. All samples shall produce IR spectra and thermograms that correspond to the reference standard when
8、tested under the same conditions. 3.3 CONDITIONING AND TEST CONDITIONS ENGINEERING MATERIAL SPECIFICATION WSF-M22P5-A1 WP 3948-b Page 2 of 9 All test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/- 2 C and 50 +/- 5 % relative humidity for not less than
9、24 h prior to testing and tested under the same conditions unless otherwise specified. 3.4 APPEARANCE Visually inspect the double sided, polymer thick film circuit board under a minimum magnification of 1.75X for the following criteria. 3.4.1 Circuit Traces 3.4.1.1 Conductor width reduction from des
10、ign, max . Conductors greater or equal 20 % to 0.3 mm . Conductors less than 0.3 mm 0.08 mm . Isolated width reduction, max 50 % (Circuit trace width reduction must be less than 2.5 mm in length.) 3.4.1.2 Cracks are not permitted Thickness reductions are allowable provided they meet the minimum cond
11、uctor thickness requirements as designated on the print. 3.4.1.3 Rework of shorts between traces is permitted provided that reworked circuit meets the requirements in para 3.4.1.1. 3.4.1.4 Voids and pinholes are permitted provided the conductor width reduction meets the requirements in para 3.4.1.1.
12、 3.4.2 Spacing Width The minimum width between non-common conductors is 0.15 mm. Small specks or stray, nonelectrically connected, metallization are permitted provided the specks are covered with soldermask that extends a minimum of 0.050 beyond the edge of each speck and a minimum of 0.100 spacing
13、exists to any circuit trace. 3.4.3 Soldermask (Covercoat) ENGINEERING MATERIAL SPECIFICATION WSF-M22P5-A1 WP 3948-b Page 3 of 9 Cracked, peeled or delaminated soldermask is not permissible. Missing soldermask is allowable provided that all conductors intended to be soldermask covered are covered and
14、 have 0.050 overlap into the adjacent space. Voids are allowable provided that voids will not allow entrapment of corrosive liquids. Soldermask on key pads or solder pads is not allowable unless specified by the design. 3.4.4 Component Diagram (Legend Silkscreen) The component diagram must be legibl
15、e from a distance of 25 cm to an observer with vision corrected to 20/20. The component diagram ink is not permitted on key pads or solderable surfaces. 3.4.5 Carbon Ink Missing or smeared carbon ink is permissible provided silver PTF ink is covered and conductor width (para 3.4.1) and spacing (para
16、 3.4.2) are met. 3.4.6 General 3.4.6.1 Conductive Paste Vias All conductive paste vias shall not have evidence of exposed base laminate. Missing holes are not permitted. 3.4.6.2 Nonscreened Through Hole Conductive pastes, metallic nodules, plating, legend silkscreen ink, soldermask or other obstruct
17、ions are not permitted in holes designated to be clear of conductive pastes. Missing holes are not permitted. 3.4.6.3 Delamination Edge delamination shall not extend in from the edge of the part to the nearest conductor by more than 20 % of the nominal conductor to edge spacing. 3.4.6.4 Coverlay Del
18、amination Coverlay delaminations are permissible as long as ENGINEERING MATERIAL SPECIFICATION WSF-M22P5-A1 WP 3948-b Page 4 of 9 the delaminations are random, no larger than 0.025 mm2, and laminated cover coat between parallel conductors is not reduced by more than 50 %. 3.5 DIMENSIONAL 3.5.1 Nonsc
19、reened Through Hole Meets Design and Print requirements The diameter of each nonscreened through hole size on each board on a panel shall be measured using pin gages or an alternative measuring instrument approved by ELD Materials Engineering. 3.5.2 Hole Location Measure the X and Y coordinates of 4
20、 holes, one selected from each of the outer corners of a representative flex circuit. Hole locations shall be determined using an optical comparator. All measurements are to be determined to four decimal places with three place accuracy and be based on the datums defined on the applicable drawing. 3
21、.5.3 External Registration Visually inspect the double sided flexible circuit board under a minimum magnification of 1.75X. 3.5.3.1 Conductive Paste to Hole Location The minimum annular ring is 0.050. 3.5.3.2 Soldermask (Covercoat) or Coverlay to Conductive Paste Conductor Measure the true position
22、location of the soldermask pattern relative to the conductive paste conductor pattern using an optical comparator. All measurements must be determined to four decimal places with three place accuracy. True Position Misregistration, 0.50 mm max 3.5.3.3 Component Diagram (Legend Silkscreen) to Conduct
23、ive Paste Conductor Pattern Measure the true position location of the component ENGINEERING MATERIAL SPECIFICATION WSF-M22P5-A1 WP 3948-b Page 5 of 9 diagram pattern relative to the conductive paste conductor pattern using an optical comparator. All measurements must be determined to four decimal pl
24、aces with three place accuracy. True Position Misregistration, 0.50 mm max 3.6 CONSTRUCTION 3.6.1 Conductive Paste Circuit Thickness (IPC-TM-650, Method 2.1.1) The thickness of each conductive paste layer shall be measured using a microsection per IPC-TM-650, Method 2.1.1. 3.6.2 Conductive Paste Thr
25、ough Hole The conductive paste through hole walls shall be viewed under 50 magnification by cutting the through holes in half along their long axis using a sharp razor. Voids in the conductive paste layers which expose the base material along the hole walls are not acceptable. 3.6.3 Dielectric Thick
26、ness The thickness of the dielectric between layers 1 and 2 shall be measured using a microsection per 3.6.1. 3.7 ELECTRICAL All PTF flexible circuits shall be tested for electrical continuity and isolation per the requirements of the particular design. 3.7.1 Electrical Continuity The resistance bet
27、ween any two common conductors shall have a resistance of less than 50 ohms or as specified on the print. 3.7.2 Electrical Isolation The resistance between any two non-common conductors shall be at least 1 megaohm when tested with a voltage of 5 volts. 3.8 DURABILITY 3.8.1 Resistance to Solvents, we
28、ight 2 % gain, max (IPC-TM-650, Method 2.3.3) ENGINEERING MATERIAL SPECIFICATION WSF-M22P5-A1 WP 3948-b Page 6 of 9 No damage or degradation of the conductor pattern (legend silkscreen), soldermask or base laminate is permitted when exposed to the following solvents: Isopropyl alcohol 2 % adipic aci
29、d solution in isopropyl alcohol 3.8.2 Moisture and Insulation 5 x 10E8 ohms Resistance, min (IPC-TM-650, Method 2.6.3.2) A set of non-common parallel circuit traces which run parallel for a minimum of 25 mm and are separated by a specific designs minimum line spacing shall be tested. 3.8.3 Thermal C
30、ycle Thermal cycle PTF flexible circuit boards 500 times from - 40 to 85 C. The profile consists of 25 minutes at each temperature extreme with a maximum transition time of 5 minutes. The PTF flexible circuit boards must meet the appearance (para 3.4) and electrical (para 3.7) requirements prior to
31、and after thermal cycling. 3.8.4 Soldermask (Covercoat) Adhesion (ASTM D 3379) Test the adhesion of the soldermask to the base laminate and conductive paste. No evidence of delamination between the covercoat and the conductive paste is permitted. 3.8.5 Coverlay Adhesion, min 0.35 kg/mm (IPC-TM-650,
32、Method 2.4.9) 3.8.6 Flexible Ductility Testing, max Resistance change 25 % (IPC-TM-650, Method 2.4.3.1, 13.0 mm mandrel) Measure the resistance change of a PTF circuit trace before and after flexing the circuit 200 times. Report the resistance change. There should be no evidence of peeling or delami
33、nation. 3.8.7 Thermal Flex Endurance, max Resistance increase 10 % Bend PTF test trace 180 degrees around a 10 mm mandrel and monitor the resistance of the circuit during 500 hours at 85 +/- 2 C. ENGINEERING MATERIAL SPECIFICATION WSF-M22P5-A1 WP 3948-b Page 7 of 9 3.9 ADDITIONAL REQUIREMENTS Specif
34、ic requirements for material and/or manufactured parts shall be specified on the Engineering drawing, Engineering parts specification and/or performance specification. All critical areas with respect to these properties shall be clearly designated on the engineering drawing. 3.10 SUPPLIERS RESPONSIB
35、ILITY All materials supplied to this specification must be equivalent in all characteristics to the material upon which approval was originally granted. Prior to making any change in the properties, composition, construction, color, processing or labeling of the material originally approved under th
36、is specification, whether or not such changes affect the materials ability to meet the specification requirements, the Supplier shall notify Purchasing, Toxicology and the affected Materials Engineering activity of the proposed changes and obtain the written approval of the Materials Engineering act
37、ivity. Test data, test samples and a new code identification are to be submitted with the request. Substance restrictions imposed by law, regulations or Ford, apply to the materials addressed by this document. The restrictions are defined in Engineering Materials Specification WSS-M99P9999-A1. 4. AP
38、PROVAL OF MATERIALS Materials defined by this specification must have prior approval by the responsible Materials Engineering activity. Suppliers desiring approval of their materials shall first obtain an expression of interest from the affected Purchasing, Design and Materials Engineering activity.
39、 Upon request, the Supplier shall submit to the affected Materials Engineering activity a completed copy of their laboratory test reports, signed by a qualified and authorized representative of the test facility, demonstrating full compliance with all the requirements of this specification (test res
40、ults, not nominal values), the material designation and code number, and test specimens for Ford evaluation. Fords engineering approval of a material will be based on its performance to this specification and on an assessment of suitability for intended processes and/or applications. Upon approval,
41、the material will be added to the Engineering Material Approved Source List. 5. GENERAL INFORMATION The information given below is provided for clarification and assistance in meeting the requirements of this specification. 5.1 PSW REQUIREMENTS ENGINEERING MATERIAL SPECIFICATION WSF-M22P5-A1 WP 3948
42、-b Page 8 of 9 When submitting the Parts Sample Warrant (PSW) for a specific double sided, polymer thick film flex circuit, certain of the requirements listed in para 3 may reference data generated for a specific “family“ of PTF flexible circuits. All other requirements must be evaluated for the spe
43、cific design. A PTF flexible circuit “family“ is defined as a group of different designs which have the following common characteristics: (a) The base flexible material is the same grade and comes from the sample supplier. (b) The minimum via diameter is greater than or equal to the minimum size tes
44、ted to qualify the family. (c) The soldermask (covercoat) or coverlay material is the same type and is supplied by the same supplier. (d) The base flexible dielectric thickness and construction are the same. (e) The minimum circuit trace and space widths are equal to or greater than the minimum circ
45、uit trace and space widths tested to qualify the family. (f) The conductive paste is the same grade and comes from the same supplier. (g) The conductive paste circuit thicknesses are the same. (h) The process flow, process parameters and equipment are equivalent. 5.2 RECOMMENDED SAMPLE SIZES AND FRE
46、QUENCY The following is a list of recommended sample sizes and frequency for each PTF flexible circuit requirement. Actual samples sizes shall be stated on the Ford approved control plan. Recommended Requirement Paragraph Sample Size Frequency Appearance 3.4 100 % Every Lot Dimensional . Hole size 3
47、.5.1 1 Panel/Lot Every Lot . Hole location 3.5.2 1 Panel/Lot Every Lot . External reg. 3.5.3 100 % Every Lot Construction 3.6 2 Boards/Lot Every Lot Electrical 3.7 100 % Every Lot Durability 3.8 Per Control Plan 18 months, max 5.3 INSTRUCTIONS AND NOTES 5.3.1 Lot Identification All parts must be mar
48、ked permanently and legibly, in any convenient location where space permits. The markings shall include: ENGINEERING MATERIAL SPECIFICATION WSF-M22P5-A1 WP 3948-b Page 9 of 9 . EIA Source Code or Vendor Logo . Date Code - Year and week of final assembly Example: 9214 for the 14th week of 1992. In li
49、eu of a date code, the supplier may identify a lot by some means mutually agreeable between the supplier and PEO and STA. All shipping containers shall be marked to identify the assembly lot, or lots, in the container. Individual containers within a shipping container shall contain only one lot with one date code. A production lot shall be defined as a group of parts manufactured as a unit on a single validated production line. Lot
