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SEMI G2-94 © SEMI 1 994 2 5 Dimensions All Dimensioning and tolerancing shall con form to Y14.5. Table 1 presents standard l eadframe dimension s. 6 Mat erials 6.1 L eadframe Base Material — T e n sile st reng th shall b…

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SEMI G2-94 © SEMI 19941
SEMI G2-94
SPECIFICATION FOR METALLIC LEADFRAMES FOR CER-DIP
PACKAGES
1 Preface
1.1 Purpose — This specification defines the materials
and dimensions for the metallic leadframe (stamped or
etched) used in the construction of Cer-DIP Package.
1.2 Scope — The criteria detailed in this document
applies to the iron-nickel leadframe (MIL-M-38510
Type A or Type B) used in Cer-DIP packages.
1.3 Units — U.S. Customary (inch -pound) or metric
(SI) units may be used at the customer’s discretion.
This specification uses the U.S. Customary units as the
prime unit.
2 Referenced Documents
1
2.1 This document specifically refers to:
MIL-I-23011 — Iron/Nickel Alloys for Sealing to
Glasses and Ceramics
MIL-M-38510 — General Specifications for
Microcircuits
MIL-STD-883 — Test Methods and Procedures for
Microelectronics
2.2 Related information may also be found in:
MIL-STD-105 — Sampling Procedures and Tables for
Inspection by Attributes
3 Terminology
bonding area — Coined area on bond fingers within a
distance of 0.762 mm (0.030") from lead tips.
bottom formed width — See Figure 3.
bow — Curvature of the leadframe strip in the vertical
plane; see Figure 1.
burr — Fragment of excess parent material attached to
the leadframe edges.
camber — Curvature of the leadframe strip edge in the
horizontal plane; see Figure 2.
coined area — The area of the bond fingers planished
to produce a flattened area for functional use; see
Figure 3.
coplanarity — The total indicator reading difference of
the lead tips in the Z direction.
1 Military Standards, Naval Publications and Form Center, 5801
Tabor Ave., Philadelphia, PA 19120
datum plane — M is datum plane; see Figure 3.
discoloration — A darkening or staining of the
aluminum (metallization).
foreign material — Any adhering residue which is not
part of the leadframe composition.
pit — A shallow surface depression or crater with a
visible edge.
planarity — Total indicator reading of the lead tips in
the Z direction relative to datum M.
projection — A raised portion of the surface indigenous
with the parent material, other than a burr.
slug marks — Random dents in the leadframe.
stamped leadframe terminology — See Figure 3.
tilt — The deviation of the plane of the coined area
from a condition parallel to the plane on datum M.
top formed width — See Figure 3.
twist — The angular rotation of one end of the
leadframe or strip with reference to the other end; see
Figure 4.
void — An absence of aluminization from a designated
area of the leadframe.
4 Ordering Information
Purchase order for Cer-DIP metallic leadframes
furnished to this specification shall include the
following items:
4.1 Current drawing of the leadfra me showing all
dimensions and tolerances, including the location of the
metallization layer.
4.2 Material,
4.3 Number of leads,
4.4 Material tensile strength,
4.5 Metallization thickness and type,
4.6 Form of leadframes (i.e., singles, scored strips, or
unscored strips),
4.7 Number of frames per strip; as applicable,
4.8 Material certification,
4.9 Packaging and marking.
SEMI G2-94 © SEMI 1994 2
5 Dimensions
All Dimensioning and tolerancing shall conform to
Y14.5. Table 1 presents standard leadframe dimensions.
6 Materials
6.1 Leadframe Base Material — Tensile strength shall
be specified per MIL-I-23011.
6.1.1 Chemical Composition — Shall conform to the
requirements of MIL-M-385l0, Type A or B.
6.1.2 Material Tensile Strength — Shall be supplied
per MIL-I-23011.
6.2 Metallization — Aluminum
6.2.1 Thickness — 100 microinches minimum, 600
microinches maximum (micromin, micromaximum).
6.2.2 Coverage — 0.030" (0.762 mm) minimum;
measured from lead tip. Maximum to be determined by
ceramic size.
6.2.3 Composition
6.2.3.1 Clad Material — 99.4% minimum aluminum.
6.2.3.2 Vapor Deposition — 99.9% minimum
aluminum.
NOTE: The two types of aluminum may exhibit different
visual appearances and non-functional characteristics after
processing.
7 Defect Limits
7.1 Burrs
7.1.1 Horizontal
7.1.1.1 Bonding Area — 0.001" (0.025 mm) max.
7.1.1.2 Other Areas — 0.002" (0.051 mm) max.
7.1.2 Vertical
7.1.2.1 Bonding Area — 0.001" (0.025 mm) max.
7.1.2.2 Other Areas — 0.002" (0.051 mm) max.
7.2 Planarity/Coplanarity — Shall not exceed the
limits shown in Table 2.
7.3 Foreign Materials — Leadframes shall be clean
and free from foreign material such as photoresist,
lubricants, solvent residue, water marks, and rust spots.
Protective coatings acceptable to both vendor and user
are not considered foreign material.
7.4 Pits and Slug Marks
7.4.1.1 Bonding Area — 0.001" (0.025 mm) max.
surface dimension × 0.0005" (0.013 mm) maximum
depth.
7.4.1.2 Other Areas — 0.010" (0.254 mm) max.
surface dimension × 0.0005" (0.013 mm) maximum
depth.
7.5 Projections
7.5.1 Bonding Area — None allowed.
7.5.2 Other Areas — .010" (.254 mm) max. surface
dimension × 0.002" (0.015 mm) maximum height.
7.6 Scratches — There shall be no scratches in the
aluminum metallization that penetrate to the underlying
base material.
7.7 Voids — All metallized areas of the leadframe
within the bonding area shall have no voids larger than
0.001" (0.025 mm) in any dimension.
7.8 Twist (formed leadframe strip ) — 0.004 inch per
inch (0.102 mm).
7.9 Coining
7.9.1 Coined Depth — Minimum 0.0005" (0.013 mm);
maximum 0.002" (0.051 mm). Minimum coined depth
may be controlled by minimum flat area.
7.9.2 Coined Flat Area — Minimum of 80% of
normal lead width; measured 0.005" (0.127 mm) back
from lead tip.
7.9.3 Coined Length — Minimum 0.025" (0.635 mm)
from lead tip.
7.10 Lead Position
7.10.1 Lead Position — A 0.007" (0.178 mm)
diameter circle must be 100% within nominal lead
position when centered at lead nominal centerline and
0.007" (0.178 mm) back from lead tip.
7.10.2 Minimum Spacing — 0.006" (0.152 mm)
minimum.
7.11 Bowing
7.11.1 Convex — 0.0025 inch per inch (0.0025 mm
per mm) maximum.
7.11.2 Concave — 0.0025 inch per inch (0.0025 mm
per mm) maximum.
7.12 Camber — 0.005 inch per inch (0.005 mm per
mm) maximum.
NOTE: Items 7.11 and 7.12 refer to scored strips only.
8 Sampling
Sampling will be determined between vendor and
customer.
SEMI G2-94 © SEMI 19943
9 Test Methods
9.1 Sequence of Events and Tests
The sequence of testing should be:
9.1.1 Degrease
9.1.2 Metallurgical Bond Adhesion (Section 9.3.1)
9.1.3 Frame Attach
9.1.4 Die Attach
9.1.5 Bond
9.1.6 Pre-Seal Bond Pull (Section 9.3.2)
9.1.7 Seal
9.1.8 Mechanical Testing (Section 9.2)
9.1.9 Lead Trim
9.1.10 Post-Seal Bond Pull (Section 9.3.2)
NOTE: It is acknowledged that the leadframe manufacturer
may not perform all these tests due to equipment and
component limitations. Regardless, leadframes must fulfill
these requirements, subject to the influence of the testing
facility and associated components.
9.2 Mechanical and Thermal
9.2.1 Temperature Cycling — Per MIL-STD-883,
Method 1010.4, Condition C.
9.2.2 Thermal Shock — Per MIL-STD-883, Method
1011.2, Condition C.
9.2.3 Centrifuge — Per MIL-STD-883, Method
2001.2, Condition E.
9.2.4 Lead Integrity
9.2.4.1 A 500°C ± 20° - 55% R.H. heat soak for 15
minutes ± 1 minute. Cooled at no more than 50°C per
minute. Afterwards the frame is clamped between
plates of a suitable size for the lead spacing (see Section
9.2.4.2). Then (3) 90° cycles are performed. Frames are
examined at 20× magnification and if cracks are
observed at the Apex A (Figure 3), then the frame is
rejected.
9.2.4.2 Plate shall be of equivalent plan-form to the
ceramic being employed for the particular frame. An
edge radius equivalent to 2T, where T is the leadframe
thickness, shall be on the contacting surface of the
plate.
9.3 Functional Test Methods
9.3.1 Metallurgical Bond Adhesion Aluminization —
The metallurgical bond between the aluminization and
the base metal shall permit the leadframe to be heated
in air to 525°C ± 10°C for five (5) minutes minimum
without evidence of aluminum peeling, blistering, or
discoloring when viewed at 20× magnification. (Dis-
coloration must not jeopardize the user’s standard part
reliability.) Subsequently, the aluminized layer must
pass the following two adhesion tests:
9.3.1.1 A cellophane type adhesive tape is firmly
applied to the aluminization and removed toward the
center of the cavity in a continuous rapid motion. This
test is to be performed over the same area three times.
No evidence of aluminum separation from the base
metal shall be visible at 20× magnification
9.3.1.2 The aluminization shall be capable of passing a
functional wirebond test without separating.
9.3.2 Lead Bond Quality — Minimum pre-seal and
post-seal bond strength test per MIL-STD-883, Method
2011.2, Test Condition D. Applicable failure
categories: A-4 and A-6.
10 Packaging and Marking
10.1 Packaging — The shipping containers and
materials shall be suitably designed to provide the
singulated components with protection against normal
transportation damage risks which include crushing,
abrasion and spillage, and exposure to moisture and
other corrosive gases. The inner packing materials must
not cause particulate contamination on the components
and shall be clean-room compatible as defined by the
customer. The components, in packing trays, shall be
sealed in a vacuum bag with a dessicant.
10.2 Packing List
10.2.1 Internal Packages — Each internal package
shall be marked as follows:
User Part Number
User Purchase Order Number
Drawing Number (User’s and Supplier’s, if
appropriate)
Supplier Shipping Lot Number
Quantity
Date of Manufacture
10.2.2 External Packages — The Packing List, located
on the outside of the container, shall provide the
following information:
User’s Part Number
User’s Purchase Order Number
Quantity
Shipping Date
Any specific instructions for receiving dock
personnel.