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SEMI G21-94 © SEMI 198 0, 1996 2 4 Orderi ng Information Purchase orders for material f u rnished to this specification shall include t he following informatio n: 4.1 L eadframe drawing showing th e area s to be plated a…
SEMI G21-94 © SEMI 1980, 19961
SEMI G21-94
SPECIFICATION FOR PLATING INTEGRATED CIRCUIT LEADFRAMES
1 Preface
1.1 Purpose — This specification details the
requirements for plating layers on leadframes intended
for use in platic semiconductor packages. It is intended
as a design guideline.
1.2 Scope — The specifications and test procedures
detailed in this document apply to all plating applied to
the internal section of leadframes. External leadframe
finishes are not included.
1.3 Units — U.S. Customary (inch-pound) or SI units
may be used at the customer's discretion. This
specification uses U.S. Customary units as the prime
unit.
2 Referenced Documents
2.1 Applicable Documents — To avoid conflicts, the
order of precedence when ordering plated leadframes
shall be as follows:
Purchase Order
Customer’s Leadframe Drawing
This Specification
Referenced Documents
Related Documents
2.2 Referenced Documents
2.2.1 SEMI Specifications
SEMI G4 — Integrated Circuit Leadframe Materials
used in the Production of Stamped Leadframes
SEMI G18 — Materials Used in the Production of
Etched Leadframes for Semiconductor Devices
SEMI — All leadframe specifications
2.2.2 ASTM Specifications
1
B 847 — 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
1 American Society of Testing and Materials, 100 Barr Harbor Drive,
West Conshohoken, PA 19428-2959
E 384 — Standard Test Method for Microhardness of
Materials
F 1269 — Test Methods for Destructive Shear Testing
of Ball Bonds
2.2.3 Military and Federal Specifications
2
MIL-C-14550 — Copper Plating, Electrodeposited
MIL-G-45204 — Gold Plating, Electrodeposited
MIL-T-10727 — Tin Plating, Electrdeposits or Hot
Dipped, for Ferrous and Non-Ferrous Metals
MIL-STD-883 — Test Methods and Procedures for
Microelectronics
QQ-N-290 — Nickel Plating, Electrodeposited
QQ-S-3651 — General Requirements for
Electrodeposited Silver Plating
2.3 Related Documents
2.3.1 Military and Federal Specifications
MIL-P-81728 — Plating Tin/Lead (Sn/Pb)
Electrodeposited
MIL-STD-105 — Sampling Procedures and Tables for
Inspection by Attributes
MIL-STD-202 — Test Methods for Electronic and
Electrical Component Parts
MIL-S-19500 — General Specification for
Semiconductor Devices
2.3.2 ISO Standards
3
ISO-3497 — Metallic Coating Measurement of Coating
Thickness, X-Ray Spectrometry Method
3 Terminology
3.1 finish (plating) — The final plating layer.
3.2 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
micro-structure and cleanliness of the die attach
surface.
2 Military Standards, Naval Publications and Form Center, 5801
Tabor Ave., Philadelphia, PA 19120
3 ANSI, 1430 Broadway, New York, NY 10018
SEMI G21-94 © SEMI 1980, 1996 2
4 Ordering Information
Purchase orders for material furnished to this
specification shall include the following information:
4.1 Leadframe drawing showing the areas to be plated
and tolerances for the location.
4.2 Plating Metal, Type, and Grade — Underplate and
finish plate.
4.3 Plating(s) thickness and tolerance.
4.4 Certification or Test Report requirements.
4.5 Reference to this specification.
4.6 Any additions to or variations from this
specification.
5 Materials
5.1 Base Material — See SEMI G4 and G18 for
leadframe base metal specifications.
5.2 Underplates — When underplates are specified,
the materials specified in Table 1 shall be used.
Table 1 Underplates
Platings Type Grade Specifications Specifications
Nickel QQN-290
Copper MIL-C-14550
Gold III A MIL-G-45204
Silver I, II, III B QQ-S-365
5.3 Finish/Underplates — The recommended finish
plating options for copper and nickel-iron alloys and the
suggested underplates are show in Table 2.
Table 2 Undercoat Finishes
Finish Copper Alloys
Nickel/Iron
Alloy
Gold MIL-G-45204
Over Base Material X
Acceptable Underplate
Nickel* X X
Silver QQ-S-365
Over Base Material X
Acceptable Underplate
Gold X
Copper X X
Tin MIL-T-10727
Over Base Material X X
Acceptable Underplate
Finish Copper Alloys
Nickel/Iron
Alloy
Nickel
XX
Copper X X
Copper MIL-C-14550
Over Base Material X X
Acceptable Underplate
Nickel QQN-290
Over Base Material X X
Acceptable Underplate
Palladium
Over Base Material
Acceptable Underplate Nickel X X
Copper X X
*Copper strike may be used under nickel.
6 Sampling
6.1 The sampling plan shall be agreed between user
and supplier.
7 Equipment
7.1 Beta Backscatter system.
7.2 Die Attach equipment.
7.3 Eutectic Die Attach heater block or hot plate
capable of 450°C ± 10°C.
7.4 Microscope 10–30× magnification with 45°
lighting.
7.5 Micro Cross-Section equipment.
7.6 Toolmaker’s Microscope
7.7 Wire Bond equipment
7.8 X-ray Fluorescence system
7.9 Solderability equipment
8 Incoming Inspection
If incoming inspection is performed, materials shall be
inspected in the following sequence:
8.1 Visual Inspection
8.2 Surface Finish
8.3 Plating Area and Thickness
8.4 Plating Quality — Heat Test a nd Adhesion Test
8.5 Functional Tests
8.5.1 Die Attach
SEMI G21-94 © SEMI 1980, 19963
8.5.2 Wire Bond
8.5.3 Solderability
8.6 Plating Hardness
9 Test Methods
9.1 Visual Inspection
9.1.1 Visually inspect the plated area using a binocular
microscope, at 10×–30× magnification for the
following rejectable conditions.
9.1.1.1 Any bare spots or missing plating in critical
areas as defined by the coined areas or minimum flat
wire bond area in the appropriate leadframe
specification.
9.1.1.2 Any peeling or blistered plating.
9.1.1.3 Any nodules in critical area as defined in
9.1.1.1.
Note 1: Nodules not exceeding 0.0005" (0.0381 mm) in a
surface dimension and 0.0005" (0.0127 mm) in height in non-
critical areas are allowed providing there are no more than
one per internal lead finger or six (6) per leadframe.
9.1.1.4 Any pits which exceed 0.0003" (0.008 mm) in
depth or 0.0005" (0.0127 mm) in a surface dimension in
critical areas or 0.001" (0.0254 mm) in depth or 0.002"
(0.051 mm) in a surface dimension in non-critical areas.
9.1.1.5 Any scratches or scrapes in the metallization
plating which expose underplate or base material.
9.1.1.6 Any scratches or scrapes in critical areas which
cause a build up of material in excess of 0.0005"
(0.0127 mm) in height.
9.1.1.7 Any foreign material, contamination, oxidation
or tarnish.
9.2 Surface Finish
9.2.1 The surface finish or brightness shall be
inspected according to procedures agreed upon between
vendor and customer.
9.3 Plating Area and Thickness
9.3.1 Plating Area
9.3.1.1 Using a toolmaker’s microscope determine if
spot plated areas meet the requirements of the
leadframe drawing for position and size tolerance.
9.3.2 Thickness
9.3.2.1 Plating thickness shall be measured at
locations agreed between vendor and customer
according to procedures detailed in ASTM B 487,
ASTM B 567, or ASTM B 568.
Note 2: Only use ASTM B 487 for thicknesses greater than
100 micro-inches (0.0025 mm).
9.4 Plating Quality — Heat Test a nd Adhesion Test.
9.4.1 Copper Plate — Test according to procedures
agreed between vendor and customer.
9.4.2 Gold and Silver Plate
9.4.2.1 Submit gold plated samples to 450°C + 10°C
for two (2) minutes in air on a die attach heater block or
hot plate and silver plated samples to 300° C + 10° C
with the same conditions.
Note 3: For silver plating thicknesses less than 100 micro-
inches (0.0025 mm), heat testing is not valid unless an
alternate time and temperature is agreed upon between the
vendor and the customer.
9.4.2.2 Visually inspect the plating under the
microscope set at 10× magnification for blistering,
peeling, and discoloration.
Note 4: For gold plating, discoloration after the heat testing is
only allowable if the fold plate thickness is less than 20
micro-inches (508 microns) by design.
Note 5: 30× magnification may be used for confirmation.
9.4.2.3 Place a strip of tape across the plated area.
Press firmly with fingertips or another smooth object.
9.4.2.4 Peel the tape quickly off the plated surface. If
there is any plating on the tape the component shall be
rejected.
9.4.3 Nickel Plate — Test according to procedures
agreed between vendor and customer.
9.4.4 Palladium Plate — Test according to procedures
agreed between vendor and customer.
9.4.5 Tin Plate — Test according to procedures agreed
between vendor and customer.
9.5 Functional Tests
9.5.1 Die Attach
9.5.1.1 Sample die, using a resin agreed between
vendor and customer, shall be attached to plated
leadframes.
9.5.1.2 Die shear tests shall be performed per MIL-
STD-883, Method 2019 or to a method agreed between
vendor and customer.
9.5.1.3 Resin bleed-out shall not exceed 0.010" (0.254
mm).
Note 6: Control samples from a previously accepted
leadframe lot shall be tested at the same time, using the same
resin batch, for comparison.