ipc-4552 印制线路板化学镍金镀覆规范

1、IPC-4552 June 2001 Specification for Electroless Nickel/Immersion Gold (ENIG) Plating for Printed Circuit Boards Plating Subcommittee (4-14) Draft Document Drafted by IPC 2215 Sanders Road, Northbrook, IL 60062 Phone : (847) 509-9700 Fax : (847) 509-9798 URL : www.ipc.org IPC-4552 Specification for Electroless Nickel/Immersion Gold (ENIG) Plating for Printed Circuit Boards Table of Content 1 SCOPE1 1.1 SCOPE1 1.2 DESCRIPTION1 1.2.1 Phosphorus/Boron Content1 1.3 OBJECTIVE.1 1.4 PERFORMANCE FUNCTI

2、ONS.1 1.4.1 Solderability.1 1.4.2 Contact Surface1 1.4.3 EMI Shielding.1 1.4.4 Conductive (Replacement for Solder) and/or Anisotropic Adhesive Interface.2 1.4.5 Connectors .2 1.4.6 Aluminum Wire Bonding 2 2 APPLICABLE DOCUMENTS.2 3 REQUIREMENTS.3 3.1 VISUAL.3 3.2 FINISH THICKNESS5 3.2.1 Electroless Nickel Thickness 5 3.2.2 Immersion Gold Thickness.5 3.3 POROSITY.5 3.4 ADHESION5 3.5 SOLDERABILITY5 3.6 CLEANLINESS.5 3.7 CHEMICAL RESISTANCE5 3.8 HIGH FREQUENCY SIGNAL LOSS.5 4 QUALITY ASSURANCE PROV

3、ISIONS5 4.1 QUALIFICATION6 4.1.1 Sample Test Coupons .6 4.2 ACCEPTANCE TESTS.6 4.3 QUALITY CONFORMANCE TESTING.6 APPENDIX 1 CHEMICAL DEFINITIONS7 APPENDIX 2 PROCESS SEQUENCE8 APPENDIX 3 QUALIFICATION OF ENIG PROCESS BY THE BOARD SUPPLIER9 APPENDIX 4 RECOMMENDATION FOR THICKNESS MEASUREMENT.10 IPC-4552 Draft Document June 2001 Page 1 of 12 IPC-4552 Specification for Electroless Nickel/Immersion Gold (ENIG) Plating for Printed Circuit Boards 1 SCOPE 1.1 Scope This specification sets the requiremen

4、ts for electroless nickel/immersion gold (ENIG) used as a surface finish for printed circuit boards. This specification is intended to set requirements for ENIG deposit thicknesses based on performance criteria. This is intended for use by supplier, manufacturer, contract manufacturer (CM) and original equipment manufacturer (OEM). 1.2 Description ENIG is an electroless nickel layer capped with a thin layer of immersion gold. It is a multifunctional surface finish, applicable to soldering, alumi

5、num wire bonding, press fit connections, and as a contact surface. The immersion golds primary function is to protect the underlying nickel from oxidation/passivation over the intended life. However, this layer is not totally impervious and it will not pass the requirements of a classic porosity test. 1.2.1 Phosphorus/Boron Content Phosphorus or boron containing reducing agents are required for the reduction of the nickel during the deposition process. Phosphorus or boron is thus incorporated in

6、 the nickel deposit. The level of these co-deposited elements should be controlled within the specified process limit. Variation of phosphorus or boron level outside the specified process limits may have adverse effects on the solderability of the finish. 1.3 Objective This specification sets the requirements specific to ENIG as a surface finish. As other finishes require specifications, they will be addressed by the IPC Plating Processes Subcommittee as part of the IPC-4550 specification family

7、. As applicable specifications are revised or superseded the subcommittee will review them and make necessary revisions to this specification. 1.4 Performance Functions 1.4.1 Solderability This primary function of ENIG is to provide a solderable surface suitable for all surface mount and through-hole assembly applications with extensive shelf life. Due to the minimal thickness of the immersion gold layer, the possibility of gold embrittlement is negligible. 1.4.2 Contact Surface There is a subst

8、antial amount of experience using ENIG for the following applications. 1.4.2.1 Membrane Switches ENIG is the de facto standard for membrane switches. The Subcommittee is conducting a study on land pattern design and ENIG thickness with SG Industries to determine the contact resistance performance criteria for ENIG as a metallic interface for membrane switches. 1.4.2.2 Metallic Dome Contacts The Subcommittee is seeking information/performance data on steel dome metallic contacts. 1.4.3 EMI Shield

9、ing ENIG is one of the surface finishes used as an interface between electromagnetic interference (EMI) shielding and the printed wiring board (PWB). IPC-4552 Draft Document June 2001 Page 2 of 12 1.4.4 Conductive (Replacement for Solder) and/or Anisotropic Adhesive Interface ENIG is ideally suited for conductive adhesive as replacement of solder, or anisotropic adhesive interface. 1.4.5 Connectors 1.4.5.1 Press Fit Press fit requirements shall meet Telcordia GR-1217-CORE. Excessive nickel thickness can lead to concerns with press fit insertion forces. 1.4.5.2 Edge Tab The ENIG surface finish is suitable for plug-to-install applications (five insertion/withdrawals) using low insertion force (LIF) or zero insertion force (ZIF) connectors. ENIG is not suitable as an edge connector for multiple insertion (more than five) withdrawals or high insertion force applications. This application generally requires an alternate metallic finish, such as electrolytic hard gol

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