1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 796 Printed-Wiring Boards STANDARD FOR SAFETYUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM ULUL COPYRIGHTED MATERIAL NOT AUTHORIZED
2、FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL Standard for Safety for Printed-Wiring Boards, UL 796 Eleventh Edition, Dated May 31, 2016 SUMMARY OF TOPICS: This new edition of ANSI/UL 796 includes the following changes in requirements: 1. Clarication of Requirements for Dire
3、ct Support of Current-Carrying Parts in Paragraph 9.3.1 2. Addition of Requirements Describing the Maximum Area Diameter on the Bond Strength and Delamination Test Pattern to Section 10.9 3. Removal of the Reference to Dissimilar Material Thermal Cycling from Table 24.1 The new and revised requireme
4、nts are substantially in accordance with Proposal(s) on this subject dated December 4, 2015 and March 11, 2016. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form by any means, electronic, mechanical photocopying, recording, o
5、r otherwise without prior permission of UL. UL provides this Standard as is without warranty of any kind, either expressed or implied, including but not limited to, the implied warranties of merchantability or tness for any purpose. In no event will UL be liable for any special, incidental, conseque
6、ntial, indirect or similar damages, including loss of prots, lost savings, loss of data, or any other damages arising out of the use of or the inability to use this Standard, even if UL or an authorized UL representative has been advised of the possibility of such damage. In no event shall ULs liabi
7、lity for any damage ever exceed the price paid for this Standard, regardless of the form of the claim. Users of the electronic versions of ULs Standards for Safety agree to defend, indemnify, and hold UL harmless from and against any loss, expense, liability, damage, claim, or judgment (including re
8、asonable attorneys fees) resulting from any error or deviation introduced while purchaser is storing an electronic Standard on the purchasers computer system. MAY 31, 2016 UL 796 tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MAY 31, 201
9、6 UL 796 tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MAY 31, 2016 1 UL 796 Standard for Printed-Wiring Boards First Edition October, 1965 Second Edition July, 1968 Third Edition August, 1973 Fourth Edition Septemb
10、er, 1978 Fifth Edition May, 1980 Sixth Edition November, 1984 Seventh Edition November, 1993 Eighth Edition October, 1999 Ninth Edition April, 2006 Tenth Edition October, 2010 Eleventh Edition May 31, 2016 This ANSI/UL Standard for Safety consists of the Eleventh Edition. The most recent designation
11、 of ANSI/UL 796 as an American National Standard (ANSI) occurred on May 31, 2016. ANSI approval for a standard does not include the Cover Page, Transmittal Pages and Title Page. Any other portions of this ANSI/UL standard that were not processed in accordance with ANSI/UL requirements are noted at t
12、he beginning of the impacted sections. The Department of Defense (DoD) has adopted UL 796 on January 20, 1995. The publication of revised pages or a new edition of this Standard will not invalidate the DoD adoption. Comments or proposals for revisions on any part of the Standard may be submitted to
13、UL at any time. Proposals should be submitted via a Proposal Request in ULs On-Line Collaborative Standards Development System (CSDS) at http:/. ULs Standards for Safety are copyrighted by UL. Neither a printed nor electronic copy of a Standard should be altered in any way. All of ULs Standards and
14、all copyrights, ownerships, and rights regarding those Standards shall remain the sole and exclusive property of UL. COPYRIGHT 2016 UNDERWRITERS LABORATORIES INC. ANSI/UL 796-2016UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MAY 31, 2016 P
15、RINTED-WIRING BOARDS - UL 796 2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONTENTS INTRODUCTION 1 Scope .6 2 Glossary .6 3 Units of Measurement 16 4 Measurement Accuracy and Testing Conditions .16 5 Supplementary Te
16、st Procedures .16 6 References 16 7 General .17 CONSTRUCTION 8 General .18 9 Base Materials 18 9.1 General 18 9.2 Metal-clad base material .20 9.3 Direct support .20 10 Conductors 21 10.1 Materials 21 10.2 Silver .21 10.3 Conductive coating .22 10.4 Edges and width .22 10.5 Pattern surfaces .22 10.6
17、 External copper foil or cladding process weight 22 10.7 Midboard conductor 23 10.8 Edge conductor 25 10.9 Maximum unpierced conductor area 25 10.10 Contact surface plating 26 10.11 Plated-through holes 27 10.12 Additional conductive plating .27 10.13 Solder limits 27 10.14 Pattern .27 11 Adhesives
18、for Conductor Bonding .28 12 Processes .28 12.1 General .28 12.2 Multiple-site processing .29 13 Permanent Coatings 29 13.1 General .29 13.2 Permanent coatings program 31 14 Plugged-Hole Materials 32 15 Embedded Components .35 16 Singlelayer (Singlesided and doublesided) Printed-Wiring Boards .36 16
19、.1 General .36 16.2 Metal-clad (MCIL/CCIL) base material program 36 17 Multilayer Printed-Wiring Boards 38 17.1 General .38 17.2 Assembly .38 17.3 Mass laminate printed wiring boards 38 17.4 Electrical insulation .39 17.5 Laminations .39 MAY 31, 2016 PRINTED-WIRING BOARDS - UL 796 3UL COPYRIGHTED MA
20、TERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 17.6 Dissimilar dielectric materials evaluation 40 17.7 Interlayer connections 40 17.8 Metal-clad laminate and prepreg materials 40 18 Metal Base Printed-Wiring Boards 41 18.1 General .41 18.2 Vertical ammabili
21、ty evaluation for metal base PWBs .43 18.3 Bond strength evaluation for metal base PWBs 45 19 Flexible Printed-Wiring Boards .45 20 Variations In Printed-Wiring Board Construction 45 PERFORMANCE 21 Test Samples 50 22 Data Collection .81 23 Microsection Analysis .83 23.1 General .83 23.2 Test samples
22、 83 23.3 Etching the sample surface 84 23.4 Material and test pattern parameter examination .84 24 Thermal Shock .85 25 Flammability .86 25.1 General .86 25.2 Samples 86 25.3 Conditioning .87 26 Bond Strength 87 26.1 After thermal shock .87 26.2 As received 87 26.3 Oven conditioning 88 27 Delaminati
23、on and Blistering .90 28 Dissimilar Dielectric Materials Thermal Cycling Test .90 28.1 General .90 28.2 Thermal cycling 90 29 Plating Adhesion 91 30 Conductive Paste Adhesion Test .91 31 Dielectric Materials Intended for Use in Fabricating High Density Interconnect (HDI) Type Constructions 92 31.1 G
24、eneral .92 31.2 HDI Vertical ammability evaluation 94 31.3 HDI Bond strength, delamination and blistering evaluation .96 31.4 Test programs for HDI PWB construction variations 98 32 Silver Migration Test 99 32.1 General .99 32.2 Procedure 101 32.3 Results 102 MARKINGS 33 General 102 MAY 31, 2016 PRI
25、NTED-WIRING BOARDS - UL 796 4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL SUPPLEMENT SA - FOLLOW-UP INSPECTION SA1 Scope SA1 SA2 Glossary SA1 SA3 Responsibility of the Manufacturer .SA2 SA4 Responsibility of the Field Representative SA3 S
26、A5 Selection of Samples for Follow-Up Testing .SA3 SA6 Follow-Up Test Program SA4 MAY 31, 2016 PRINTED-WIRING BOARDS - UL 796 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL INTRODUCTION 1 Scope 1.1 These requirements apply to rigid printed
27、-wiring boards and exible printed-wiring board for use as components in devices or appliances. Compliance with these requirements does not indicate that the product is acceptable for use as a component of an end product without further investigation. 1.2 The exible printed-wiring boards covered by t
28、hese requirements consist of conductors affixed to insulating base lm, with or without a cover-lay lm, with midboard connections. 1.3 These requirements do not cover exible printed-wiring boards of laminated-lm construction in which the conductors are parallel to each other and are completely covere
29、d by the base lm with only point-to-point end connections. 1.4 These requirements do not apply to exible, ex-to-install, rigid, and multilayer rigid ex composite interconnect constructions with and without stiffener and adhesive materials as exible materials interconnect constructions (FMICs) for us
30、e as components in devices or appliances that are covered by the Standard for Flexible Materials Interconnect Constructions, UL 796F. 2 Glossary 2.1 For the purpose of this Standard the following denitions apply. 2.2 ADDITIVE PROCESS A selective or non-selective process used to deposit a pattern of
31、conductor material(s) on clad or unclad base material. 2.3 ADHESIVE A substance such as glue or cement used to join, bond, or fasten materials or objects together. 2.4 AS RECEIVED Specimens or samples in an unconditioned state, prior to being subject to conditioning, or without a history of conditio
32、ning. 2.5 BASE MATERIAL An organic or inorganic material used to support a pattern of conductor material. The base material may be rigid or exible. 2.6 BASE MATERIAL THICKNESS The thickness of the base dielectric material excluding conductive foil or material deposited on the surface of the base mat
33、erial. If an adhesive is used to adhere the conductor material to the base material, the adhesive thickness and application surfaces (base material sides) is indicated separately. 2.7 BLIND VIA A via extending to only one surface of the board construction. 2.8 BLISTERING Localized area of delaminati
34、on. See 2.44, Delamination. 2.9 BONDING LAYER An adhesive layer used to bond discrete layers of multilayer board constructions. Also known as Prepreg. MAY 31, 2016 PRINTED-WIRING BOARDS - UL 796 6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM
35、UL 2.10 BUILD-UP THICKNESS Overall thickness of a combination of materials. Unless otherwise indicated, the build-up thickness will refer to the overall thickness of a board construction where no internal or external conductor material resides. 2.11 BUILT-UP MULTILAYER (BUM) Multiple layers of HDI m
36、aterials. 2.12 BURIED VIA A via that does not extend to the surface of the board construction. 2.13 CAP LAYER A single sided copper clad laminate bonded to the external surface of the multilayer board with bonding layer material prepreg (b-stage). 2.14 CIRCUIT Electrical devices and elements interco
37、nnected to perform a desired electrical function. 2.15 CIRCUITRY LAYER Conductor layer or plane in or on a printed wiring board. 2.16 CLADDING See Conductive Foil. 2.17 CLAD MATERIAL See Metal Clad Base Material. 2.18 COATING A nonmetallic substance applied by some process, such as dipping, screenin
38、g, spraying, or melt-ow. 2.19 COMPONENT An individual part or combination of parts intended to perform a desired function. 2.20 CONDITIONING Exposure of test samples to an environment for a period of time, prior to or after testing and prior to evaluation. 2.21 CONDUCTIVE (ELECTRICAL) The ability of
39、 a substance or material to conduct electricity. 2.22 CONDUCTIVE FOIL A thin metal sheet intended for forming a conductor pattern on a base material. 2.23 CONDUCTIVE PASTE An organic or inorganic paste substance capable of transmitting electricity, used for circuit conductors, including but not limi
40、ted to carbon, copper, and silver. 2.24 CONDUCTOR A trace or path for electricity to transmit in a conductor pattern. 2.25 CONDUCTOR ADHESIVE Adhesive material used to attach conductor material to a base material. 2.26 CONDUCTOR AVERAGE TRACE WIDTH The average width of a length of conductor trace. 2
41、.27 CONDUCTOR BASE WIDTH The width of a conductor at the interface of the base material as determined by microsection analysis. This width is used to determine bond strength/peel strength values. 2.28 CONDUCTOR LAYER A single plane of a conductor material or pattern on a base material. MAY 31, 2016
42、PRINTED-WIRING BOARDS - UL 796 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 2.29 CONDUCTOR MATERIAL An organic or inorganic substance capable of transmitting electricity, used for circuit conductors, including but not limited to copper,
43、tin, nickel, gold, carbon paste, copper paste, silver paste, ruthenium oxide paste, etc. 2.30 CONDUCTOR PATTERN The path, design, or conguration of conductor material on the base material, including but not limited to conductor traces, lands, through-holes, and vias. 2.31 CONDUCTOR SPACING The minim
44、um distance between adjacent conductors. 2.32 CONDUCTOR THICKNESS The thickness of the conductor and additional metallic platings or coatings, excluding non-conductive coatings. 2.33 CONDUCTOR TRACE A linear conductor path of a conductor circuit. 2.34 CONDUCTOR WIDTH The width of the conductor as vi
45、ewed from a top view or at the plane of the surface of a base material, whichever is less. See Conductor Base Width. 2.35 CONFORMAL COATING A protective covering applied on a printed wiring board capable of conforming to the conguration of objects coated, used to increase the dielectric voltage-with
46、stand capability between conductors, and/or to protect against environmental conditions. 2.36 CONSTRUCTION A variation in laminate materials, including but not limited to base material, laminate, prepreg, dielectric materials, or other insulation materials. Variations include singlelayer, multilayer
47、, and composite constructions. 2.37 CONTACT FINGER A conductive surface usually located at an edge of a printed-wiring board used to provide electrical connection by pressure contact. 2.38 CONTINUITY An uninterrupted path for the ow of electrical current in a circuit. 2.39 CORE MATERIAL The innermos
48、t material of printed-wiring board which may be used to support a subsequent layer or layers of dielectric material and conductor pattern. Core material may be an organic or inorganic material, with or without integral dielectric material. Core material may be referred to as substrate material. 2.40
49、 COUPON A test vehicle constructed to represent a production printed wiring board to be used for testing. See Sample. 2.41 CRITICAL OPERATION Production process or fabrication step considered potentially detrimental to the materials subject to the operation. 2.42 CURRENT The movement or ow of electrons in a conductor due to a voltage potential difference to the materials subject to the operation. 2.43 DECLAD A diel
