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SEMI G8-94 © SEMI 1 983, 199 6 1 SEMI G8-94 TEST METHOD FOR GOLD PLA TI NG 1 Preface 1.1 Pur pose — This t est m ethod d e s cr ibes procedu res to determine gold plating quality. 1.2 Scope — Thes e meth ods apply t o go…

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SEMI G6-89 © SEMI 1983, 1996 2
NOTICE: These standards do not purport to address
safety issues, if any, associated with their use. It is the
responsibility of the user of these standards to establish
appropriate safety and health practices and determine
the applicability of regulatory limitations prior to use.
SEMI makes no warranties or representations as to the
suitability of the standards set forth herein for any
particular application. The determination of the
suitability of the standard is solely the responsibility of
the user. Users are cautioned to refer to manufacturer’s
instructions, product labels, product data sheets, and
other relevant literature respecting any materials
mentioned herein. These standards are subject to
change without notice.
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compliance with this standard may require use of
copyrighted material or of an invention covered by
patent rights. By publication of this standard, SEMI
takes no position respecting the validity of any patent
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item mentioned in this standard. Users of this standard
are expressly advised that determination of any such
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of such rights, are entirely their own responsibility.
Copyright by SEMI® (Semiconductor Equipment and Materials
International), 3081 Zanker Road, San Jose, CA 95134. Reproduction o
f
the contents in whole or in part is forbidden without express written
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SEMI G8-94 © SEMI 1983, 19961
SEMI G8-94
TEST METHOD FOR GOLD PLATING
1 Preface
1.1 Purpose — This test method describes procedures
to determine gold plating quality.
1.2 Scope — These methods apply to gold plating on
cofired ceramic or metal packages. The grade, hardness,
and thickness of the gold plating shall be specified per
MIL-G-45204 unless otherwise agreed between vendor
and customer.
Note 1: The gold plate may be over refractory metal on
cofired ceramic packages or over an underplate on metal
packages.
2 Applicable Documents
2.1 Referenced Documents
2.1.1 SEMI Specifications — All SEMI package
specifications
2.1.2 ASTM Specifications
1
B 384 — Standard Test Method for Microhardness of
Materials
B 487 — Test Method for Measurement of Metal and
Oxide Coating Thicknesses by Microscopic
Examination of a Cross-Section
B 567 — Method for Measurement of Coating
Thickness by the Beta Backscatter Method
B 568 — Method for Measuring Coating Thickness by
X-Ray Spectrometry
F 1269 — Test Methods for Destructive Shear Testing
of Ball Bonds
2.1.3 Military and Federal Specifications
2
MIL-STD-750 — Test Methods for Semiconductor
Devices
MIL-STD-883 — Test Methods and Procedures for
Microelectronics
MIL-G-45204 — Gold Plating, Electrodeposited
2.2 Related Documents
Military and Federal Specifications
MIL-STD-105 — Sampling Procedures and Tables for
Inspection by Attributes
1 American Society for Testing and Materials, 100 Barr Harbor
Drive, West Conshohoken, PA 19428-2959
2 Military Standards, Naval Publications and Form Center, 5801
Tabor Avenue, Philadepphia, PA 19120
MIL-STD-202 — Test Methods for Electronic and
Electrical Componenet Parts
MIL-STD-19500 — General Specification for
Semicondutor Devices
MIL-M-38510 — General Specification for
Microcircuits
3 Summary of Method
Various test methods are described or referenced to
determine gold plating quality for the following items:
Visual Appearance
Plating Thickness
Plating Adhesion
Functional tests
Salt Atmosphere
Hardness
4 Significance and Use
4.1 Significance — Poorly plated components result in
lowered yields during package assembly operations or
to reliability problems.
4.2 Use — The methods described in this document
may be used by vendors to test gold plated components
as part of their process control program, or by
customers at incoming inspections.
The methods are to used in conjunction with individual
component specifications.
5 Terminology
5.1 blister (metal) — An enclosed, localized
separation of a metallization layer from its base
material (such as ceramic or another metal layer) that
does not expose the underlying layer.
5.2 discoloration — The change in color of any plated
metallization, gold, silver, aluminum, etc., as detected
by the unaided eye after the application of heat to the
metallization. The metallization may be over base
metal, another plated layer, or on refractory metal.
5.3 peeling (flaking) — Any separation of the plated,
vacuum deposited or clad metal from the base metal of
a leadframe, lead, pin, heatsink, or seal ring, from an
underplate, or from refractory metal on a ceramic
package. Peeling exposes the underlying material. Also
called flaking.
SEMI G8-94 © SEMI 1983, 1996 2
5.4 pitting (plated metal layer) — Unspecified
depressions in the plated layer, not the underlying
layer(s). Such pits may be caused by incorrect plating
conditions.
5.5 resin bleed-out (die attach) — The surface creep of
a resin used for die attach beyond the outer perimeter of
the bulk of the resin (filler). For a given resin
formulation, the resin creep may be exacerbated by the
microstructure and cleanliness of the die attach surface.
5.6 scratch — An abrasion in the surface of a
metallization layer which exposes the base material.
6 Interferences
6.1 Avoid contaminating the gold plated surface (e.g.,
with finger oils), prior to performing the tests. Such
contamination may effect visual appearance, and die
attach, wire bond, and solderability functional tests.
7 Equipment
7.1 Beta Backscatter system
7.2 Die Attach equipment
7.3 Eutectic Die Attach heater block or lot plate
capable of 450 °C ± 10 °C.
7.4 Microscope 10-30× magnification with vertical
lighting.
7.5 Micro Cross-Section equipment
7.6 Wire Bond equipment
7.7 X-Ray Fluorescence System
8 Sampling
8.1 Sampling plans shall be agreed between vendor
and customer.
9 Test Sequence
When the test methods are used at incoming inspection
the sequence of test shall be as follows:
9.1 Visual Appearance — See Section 10.1.
9.2 Plating Thickness — See Section 10.2.
9.3 Plating Adhesion — See Section 10.3.
9.4 Functional Tests (Die Attach, Wire Bond, and
Lead Solderability) — See Section 10.4.
9.5 Salt Atmosphere Test — See Section 10.5.
9.6 Plating Hardness — See Section 10.6.
10 Test Procedures
10.1 Visual Inspection
10.1.1 Components shall be visually inspected
according to the appropriate component specification
for plating requirements.
10.1.2 Surface Structure — The gold plate shall be
smooth matte to semi-bright in appearance. Minor
variations in color are not cause for failure at this stage
unless there is evidence of corrosion, peeling, or pitting
in the plating layer.
Note 2: For the purposes of this test method, particular
attention shall be observed in relation to blisters and adhesion
problems with the plating layer.
10.2 Plating Thickness
10.2.1 Plating thickness shall be measured at locations
agreed upon between vendor and customer.
10.2.2 Plating thickness may be measured by one of
the following techniques, which are listed in order of
preference.
ASTM Method B 568
ASTM Method B 567
ASTM Method B 487
Note 3: Method B 487 shall only be used for thicknesses
greater than 100 microinches (0.0025 mm).
10.3 Plating Adhesion
10.3.1 Submit samples to 450 °C ± 10°C for two (2)
minutes in air on a die attach heater block or hot plate.
10.3.2 Visually inspect the plating under the
microscope set at 10× magnification for blistering,
peeling, and discoloration.
Note 4: Discoloration after the heat testing is only allowable if
the gold plate thickness is less than 20 micro-inches (508
micro mm) by design. Amount and type of discoloration shall
be agreed upon between vendor and customer.
Note 5: 30×
magnification may be used for confirmation.
10.3.3 Adhesion Tape Test — Flat Surface
10.3.3.1 Place a strip of tape across the plated area.
Press firmly with finger tips or another smooth object.
10.3.3.2 Peel the tape quickly off the plated surface. If
there is any plating on the tape the component shall be
rejected.
10.3.4 Lead Finish Adherence — Bend Test
10.3.4.1 Bend the leads once through a 90° angle on a
diameter equal to the lead diameter or thickness.
10.3.4.2 Visually inspect the plating under the
microscope set at 10× magnification for evidence
peeling or cracking of the plated layer.