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SEMI G55-93 © SEMI 1993, 2004 1 SEMI G55-93 (Reapproved 1104) TEST METHOD FOR MEASUREM ENT OF SILVER PLATING BRIGHTNESS This test method was technically reapproved by th e Global Assembly & Packaging Comm ittee and i…

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SEMI G54-93 © SEMI 19935
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SEMI G55-93 © SEMI 1993, 2004 1
SEMI G55-93 (Reapproved 1104)
TEST METHOD FOR MEASUREMENT OF SILVER PLATING
BRIGHTNESS
This test method was technically reapproved by the Global Assembly & Packaging Committee and is the
direct responsibility of the Japanese Packaging Committee. Current edition approved by the Japanese
Regional Standards Committee on July 23, 2004. Initially available at www.semi.org September 2004; to be
published November 2004. Originally published in 1993.
1 Preface
1.1 Use — This test may be used for process control
and outgoing inspection at the supplier or by the user
for incoming inspection.
2 Scope
2.1 This method describes the standard method for
measuring the brightness of silver plating on
semiconductor leadframes.
NOTE 1: This method determines quantitative measures
which are not related directly to the traditional “Dull,” “Semi-
Bright” and “Bright” descriptors for silver plating.
NOTICE: This standard does not purport to address
safety issues, if any, associated with its use. It is the
responsibility of the users of this standard to establish
appropriate safety and health practices and determine
the applicability of regulatory or other limitations prior
to use.
3 Referenced Standards
3.1 SEMI Standard
SEMI G21 — Specification for Plating Integrated
Circuit Leadframes
3.2 JIS Specifications
1
JIS H8621 — Electroplated Coatings of Silver for
Engineering Use
JIS Z8722 — Method of Measurement for Color of
Reflecting or Transmitting Objects
JIS Z8741 — Method of Measurement for Specular
Glossiness
3.3 Military and Federal Specifications
2
QQ-S-365 — General Requirements for Electro-
deposited Silver Plating
1 Japanese Industrial Standards, Available through the Japanese
Standards Association, 1-24, Akasaka 4-Chome, Minato-ku, Tokyo
107-8440, Japan. Telephone: 81.3.3583.8005; Fax: 81.3.3586.2014,
Website: www.jsa.or.jp
2 United States Military Standards, Available through the Naval
Publications and Forms Center, 5801 Tabor Avenue, Philadelphia,
PA 19120-5099, USA. Telephone: 215.697.3321
NOTICE: Unless otherwise indicated, all documents
cited shall be the latest published versions.
4 Significance
4.1 Brightness values indicate surface roughness for
given plating conditions. Surface roughness affects the
wettability of resinous die attach processes on
leadframes. If the surface is too smooth, poor wetting
may occur which results in low die share strength
values.
4.2 Brightness variations may also affect the ability of
the pattern recognition systems used on assembly
equipment to recognize the set points.
5 Summary of Method
5.1 The method is based on the use of a GAM
Densitometer. This method is chosen as the standard
because of the small measurement area requirements
and the high accuracy of the method for typical silver
plating brightness used on leadframes.
5.1.1 This method is based on the measurement of the
reflectance of light at 45° from a surface illuminated
from a light source perpendicular to the surface. This
value of Reflectance (R) gives a Density Value (D)
based on the following formula:
D = log 1/R
Density is a measure of the Brightness.
6 Interferences
6.1 Surface Finish
6.1.1 Brightness values depend on surface roughness.
A rough surface shows a low brightness value when
compared to a smooth surface. Variable plating
conditions, such as the addition of brighteners to the
plating solution, may give brightness results, which are
not comparable for the acceptance of plated leadframes.
6.1.2 Scratches and other flaws in the surface will
affect reflectance.
6.2 Storage Time and Conditions
6.2.1 Figure 1 shows the brightness results for
leadframes subjected to indoor, atmospheric storage for
SEMI G55-93 © SEMI 1993, 2004 2
an extended time. Results are shown for silver plating
on copper alloy and Alloy 42 leadframes.
6.2.2 Leadframes shall be stored in conditions agreed
between supplier and customer in order to limit
atmospheric tarnishing, and brightness measurements
shall be taken within an agreed time of delivery.
6.3 Degradation of the standards will affect calibration.
7 Equipment
7.1 GAM Densitometer or equivalent.
8 Sampling
8.1 A sampling plan shall be agreed between user and
supplier.
9 Preparation of Samples
9.1 No special preparation requirements are necessary.
Do not contaminate the samples by touching with bare
hands.
10 Measurement Conditions
10.1 To confirm the lamp is on enough to measure the
brightness values. (Lamp intensity is automatically
calibrated.)
11 Equipment Setup and Calibration
11.1 Equipment Setup
11.1.1 Set up and turn on the equipment according to
the manufacturer’s instructions.
11.1.2 Allow at least 30 minutes for equipment
stabilization before beginning measurements.
11.2 Calibration
11.2.1 Calibration shall be performed using standard
black and white plates.
11.2.2 The equipment shall be recalibrated every 30
minutes.
12 Procedure
12.1 Procedure
12.1.1 Measurements shall be made close to the center
of the die pad, if possible. In those situations where the
die pad is not plated, the measurement site shall be
agreed between user and supplier.
12.1.2 Measure all the selected samples according to
the equipment manufacturer’s instructions. Take three
readings on each sample and obtain an average result
for that sample.
12.2 Results
12.2.1 Brightness values shall be rounded to the first
decimal place.
13 Report
13.1 The report, when used by a supplier to certify a
customer’s requirements or by the customer at
incoming inspection shall contain, at least, the
following information, other information which is
reported shall be agreed between supplier and customer.
13.2 Supplier’s Lot Number and Date of Shipment
13.3 Test Conditions
13.4 Results from Section 11. (SPC charting
techniques may be used to monitor results for each
leadframe type and plating requirement.)
14 Repeatability and Precision
14.1 Repeatability
14.1.1 Values for brightness based on use of a
densitometer are repeatable within ± 0.003.
14.2 Precision
14.2.1 Precision for brightness values based on use of a
densitometer is ± 0.015.