IPC-4556 印制板化学镍钯浸金（ENEPIG）规范ENG - 第14页

2.7 Terms, Definitions and Acronyms The deﬁnition of all terms used herein shall be as speciﬁed in IPC-T -50 and as deﬁned below: MTO (Metal Turnover) – A measure of electroless or immersion plating bath ‘ ‘age,’ ’ MTO i…

if the end use environment is considered harsh. For additional information on ENEPIG corrosion resistance to MFG, see

Appendix 11.

1.4.7.2 High Frequency Signal Loss Higher frequency (>3 GHz) applications may experience signal loss on full build

(i.e., where ENEPIG is applied over both traces and pads) designs. Signal loss is minimal when only the pads (but not the

traces) are plated with the ﬁnish.

2 APPLICABLE DOCUMENTS AND TERMS AND DEFINITIONS

2.1 IPC

J-STD-003 Solderability Tests for Printed Boards

IPC-1601 Printed Board Handling and Storage Guidelines

IPC-2221 Generic Standard on Printed Board Design

IPC-6011 Generic Performance Speciﬁcation for Printed Boards

IPC-6012 Qualiﬁcation and Performance Speciﬁcation for Rigid Printed Boards

IPC-6013 Qualiﬁcation and Performance Speciﬁcation for Flexible Printed Boards

IPC 5704 Cleanliness Requirements for Unpopulated Printed Boards

IPC-TM-650 Test Methods Manual

2.3.25 Detection and Measurement of Ionizable Surface Contaminants by Resistivity of Solvent Extract (ROSE)

2.4.1 Adhesion, Tape Testing

2.6.3.5 Bare Board Cleanliness by Surface Insulation Resistance

2.6.14.1 Electrochemical Migration Resistance Test

2.2 American Society for Testing and Materials (ASTM International)

ASTM B568 Standard Test Method for Measurement of Coating Thickness by X-Ray Spectrometry

ASTM B733 Standard Speciﬁcation for Autocatalytic (Electroless) Nickel-Phosphorus Coatings on Metal

ASTM B827 Standard Practice for Conducting Mixed Flowing Gas Environmental Tests

ASTM B845 Standard Guide for Mixed Flowing Gas Tests for Electrical Contacts

2.3 JEDEC

JESD 213 Common Test Method for Detecting Component Surface Finish Materials

2.4 Defense Standardization Program

MIL-STD-883 Method 2011.7 Test Method Standard, Microcircuits - Bond Strength (Destructive Bond Pull Test)

MIL-STD-1580 Department of Defense Test Method Standard (Destructive Physical Analysis for Electronic, Electro-

magnetic, and Electromechanical Parts)

MIL-C-28859 General Speciﬁcation for Connector Component Parts, Electrical Backplane, Printed-Wiring

2.5 Telcordia Technologies, Inc.

Telcordia GR-1217-CORE Generic Requirements For Separable Electrical Connectors Used In Telecommunications Hard-

ware

2.6 International Organization for Standardization (ISO)

ISO-4527 Auto-Catalytic Nickel-Phosphorous Coatings; Speciﬁcations and Test Methods, Annex A: Determination of Coat-

ing Thickness and Annex D: Determination of Coating Composition (Nickel and Phosphorous Content).

1. www.ipc.org

2. Current and revised IPC Test Methods are available on the IPC Web site (www.ipc.org/html/testmethods.htm)

3. www.astm.org

4. www.jedec.org

5. www.dsp.dla.mil

6. www.telcordia.com

7. www.iso.org

January 2013 IPC-4556

2.7 Terms, Definitions and Acronyms The deﬁnition of all terms used herein shall be as speciﬁed in IPC-T-50 and as

deﬁned below:

MTO (Metal Turnover) – A measure of electroless or immersion plating bath ‘‘age,’’ MTO is a period of operation during

which the sum of the periodic replenishments of the metal being deposited is equal to the amount of metal in the initial bath

makeup. For example, if the metal concentration in an electroless bath is 5 grams per liter and the bath is 100 liters in size,

then one MTO is the period of useage during which 500 grams of metal is added back into the bath by replenishment as the

metal is actively being deposited out of the bath. Depending on how heavily an electroless or immersion bath is being

‘worked’, the time taken for one MTO may range from as little as a few hours to a week or more. It is common for an

electroless or immersion plating bath to last for multiple MTOs before being removed from service and fully replaced.

3 REQUIREMENTS

Table 3-1 Requirements of Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG) Plating

Inspection Class/Test Frequency (A.Q.L.) Requirements

Tests Test Method 1 2 3/3A Paragraph Remarks

General:

Visual Visual 4.0 2.5 1.0 3.1

Uniform color and complete

coverage of surface to be coated.

Electroless Nickel

Thickness

Appendices 4 and 9 6.5 4.0 2.5 3.2.1

3 to 6 µm [118.1 to 236.2 µin] at

± 4 sigma (standard deviations)

from the mean as measured on

a nominal pad size of 1.5 mm x

1.5 mm [0.060 in x 0.060 in] or

equivalent area.

Electroless Palladium

Thickness

Appendices 4 and 9 6.5 4.0 2.5 3.2.2

0.05 to 0.30 µm [2 to 12 µin] at

± 4 sigma (standard deviations)

from the mean as measured on

a nominal pad size of 1.5 mm x

1.5 mm [0.060 in x 0.060 in] or

equivalent area.

Immersion Gold

Thickness

>0.030µm [1.2 µin] a

Appendices 4 and 9 6.5 4.0 2.5 3.2.3

t - 4 sigma

(standard deviations) below the

mean as measured on a nominal

pad size of 1.5 mm x 1.5 mm

[0.060 in x 0.060 in] or equivalent

area.

Physical:

Adhesion/Tape Test

IPC-TM-650,

Method 2.4.1

6.5 4.0 4.0 3.4

No evidence of plating and/or

solder mask removed.

Solderability J-STD-003 4.0 2.5 2.5 3.5

Refer to the applicable

performance speciﬁcation.

Force Measurement -

When required, the

speciﬁed provisions

apply:

Force Measurement

Test

4.0 2.5 2.5 3.5.1

0.14 mN/mm minimum for

Eutectic SnPb testing.

0.19 mN/mm minimum for SAC

305 testing.

Environmental:

Cleanliness IPC- 5704

When tests required, AQL

shall be AABUS

3.6

Refer to applicable performance

speciﬁcation.

SIR

IPC-TM-650,

Method 2.6.3.5;

GR78-Core

When tests required, AQL 3.6

shall be AABUS 3.6

1.0E+08 ohms

1.0E+10 ohms

Electrolytic Corrosion

IPC-TM-650,

Method 2.6.14.1

When tests required, AQL

shall be AABUS

3.7 AABUS

IPC-4556 January 2013

3.1 Visual ENEPIG surfaces shall be inspected in accor-

dance with the visual examination sections of the IPC-6010

series speciﬁcations, speciﬁcally IPC-6012 which speciﬁes the

use of a nominal magniﬁcation of 1.75X (approx. 3 diopters).

The coverage shall be complete and the ﬁnish shall be uni-

form on the surfaces to be plated (see Figure 3-1). For higher

magniﬁcation analysis, Figures 3-2 to 3-4 are offered for ref-

erence purposes. There shall be no extraneous plating or

nickel foot (see Figure 3-2), edge pull back (see Figure 3-3) or

skip plating (see Figures 3-4, 3-5 and 3-6) on the surfaces of

all classes of product.

Figure 3-1 Uniform Plating

IPC-4556-3-2a/2b

Figure 3-2 Extraneous Plating or Nickel Foot

IPC-4556-3-3a/3b

Figure 3-3 Edge Pull Back

IPC-4556-3-4a/4b

Figure 3-4 Skip Plating

January 2013 IPC-4556