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SEMI G47-88 © SEMI 1988 2 Figure 3 Coined Area Figure 4 Crossbow Figure 5 Lead Tw ist 4 Orderi ng Information Purchasing orders for leadf rames for plastic molded quad f lat pack packages furnished to th is specification…

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SEMI G47-88 © SEMI 19881
SEMI G47-88
SPECIFICATION FOR PLASTIC MOLDED QUAD FLAT PACK
LEADFRAMES
1 Preface
This specification defines the acceptance criteria for
leadframes designed for assembly of JEDEC registered
publication 95 standard outlines for “Plastic Quad Flat
Pack 0.025" lead spacing (gull wing) packages”. It is a
design guideline for packaging engineers, leadframe
stampers and etchers, mold and trim/form tooling
manufacturers. It has been developed to meet the
requirements of assemblers using automatic and manual
equipment.
2 Applicable Documents
2.1 SEMI Specifications
SEMI G4 — Specification, Integated Circuit Leadfame
Materials in the Production of Stamped Frames
SEMI G18 — Specification, Integrated Circuit
Leadframe Materials Used in the Production of Etched
Frames
SEMI G10 — Standard Method, Mechanical
Measurement for Plastic Package Leadframes
SEMI G21 — Specification, Plating Integrated Circuit
Leadframes
2.2 ANSI Specification
1
Y 14.5M-1982 — Dimensioning and Tolerancing
2.3 JEDEC Specification
2
Registration 95 — Plastic Quad Flat Pack, 0.025" Lead
Spacing (Gull Wing)
2.4 Military Specification
3
MIL-STD-105 — Sampling Procedures and Tables for
Inspection by Attributes
3 Selected Definitions
burr — a fragment of excess material either horizontal
or vertical attached to the leadframe.
camber — curvature of the leadframe strip edge (see
Figure 1).
1 ANSI, 1430 Broadway, New York, NY 10018
2 Military Standards, Naval Publications and Form Center, 5801
Tabor Ave., Philadelphia, PA 19120
3 JEDEC, 2001 Eye Street, N.W., Washington, D.C. 20006
coil set — Longitudinal bowing of the leadframe (see
Figure 2).
Figure 1
Camber
coined area — that area at the tip end of the bond
fingers coined to produce a flattened area for functional
use (see Figure 3).
Figure 2
Coil Set
crossbow — transverse bowing of the leadframe (see
Figure 4).
lead twist — angular rotation of bonding fingers (see
Figure 5).
pits — shallow surface depressions or craters in the
leadframe material.
true position circle — that circle with its center
positioned at the center of the coined lead defines the
design position of the lead tip.
SEMI G47-88 © SEMI 1988 2
Figure 3
Coined Area
Figure 4
Crossbow
Figure 5
Lead Twist
4 Ordering Information
Purchasing orders for leadframes for plastic molded
quad flat pack packages furnished to this specification
shall include the following items:
4.1 Drawing no. and revision leve l.
4.2 Material, alloy specification.
4.3 Lead count, and confirming no . of units per strip.
4.4 Requirement for material certification.
4.5 Leadframe plating specifications.
5 Dimensions
5.1 Tables 1, 2, 3, and 4.
5.2 Reference Figures 6 and 7 and Details A and B.
6 Defect Limits and Parameters (to measure,
see SEMI G10, Standard Method for
Mechanical Measurement for Plastic Package
Leadframes)
6.1 Lead Tip Width
6.1.1 Minimum Lead Tip Width — Shall be as agreed
to between supplier and purchaser.
6.1.2 Minimum Flat Wire Bonding Area — 80% of
nominal lead width and 0.025" (0.635 mm) in length.
6.2 Coining and Metal Clearance
6.2.1 Coined Depth — 0.0005" (0.013 mm) minimum
to 30% material thickness maximum (stamped frames
only).
6.2.2 Dimensions shown on drawings are before
coining.
6.2.3 Maximum Coining Bulge — (Stamped frame
only) shall not exceed 0.002" (0.051 mm) per edge and
shall be governed by metal to metal clearance
requirements (lead to lead and lead to pad).
6.2.4 Metal-to-Metal Clearance — Shall be as agreed
to between supplier and purchaser.
6.3 Lead Twist — Shall not exceed 3.5 or 0.0006"
(0.015 mm) per 0.001" (0.254 mm) of lead width.
6.4 Burrs — Shall be firmly attached and able to
withstand a probe force of 10 grams. All burrs vertical
and horizontal in any location shall not exceed 0.001"
(0.0254 mm).
6.5 Die Pad Tilt and Flatness — (See SEMI G10 for
measurement method.)
6.5.1 Tilt — 0.001" (0.025 mm) maximum per 0.100"
(2.54 mm) of length or width in the undepressed state,
and 0.002" (0.051 mm) maximum per 0.160" (4.06
mm) of length or width in the depressed state, when
measuring corner to corner: overall maximum not to
exceed a total of 0.006" (0.152 mm).
6.5.2 Flatness — 0.0002" (0.005 mm) per 0.100"
(2.54 mm) pad length when measuring from the center
to the average of four corners. The corners are defined
at 0.005" (0.127 mm) from each edge.
6.6 Pits and Slug Marks
6.6.1 Within the functional area and on external leads,
no slug marks and pits shall exceed 0.0003" (0.008
SEMI G47-88 © SEMI 19883
mm) in depth and 0.0005" (0.0013 mm) in length (see
SEMI G4).
6.6.2 They shall not affect lead strength and shall not
exceed 0.001" (0.0254 mm) in depth and 0.002" (0.051
mm) in length in non-functional areas.
6.7 Material thickness for both alloy 42 and copper
alloys is 0.006" (0.152 mm), ± 0.00015" (0.0038 mm)
for all lead counts.
NOTE — The material thickness tolerance dimension listed in
Section 6.7 is currently under committee review and is
expected to be revised to ± 0.0002".
6.8 Internal Position Tolerance — The centerline of
all leadframe features must be within T.P.T. 0.002"
(0.051 mm) relative to center line of pilot holes on rail.
6.9 Progression
6.9.1 Single progression of one frame is T.P.T. 0.002"
(0.051 mm).
6.9.2 Accumulated progression tolerance over the strip
length (measured from pitch line tooling hole to pitch
line tooling hole, across the strip length minus two
units) is within T.P.T. of 0.004" (0.102 mm).
6.10 Strip Cut Off Location — Shall be within T.P.T.
0.006" (0.154 mm) of nominal strip length.
6.11 Strip Width Tolerance — T.P.T. 0.004" (0.102
mm) for copper and alloy 42 materials.
6.12 Camber — Shall not exceed 0.002" (0.051 mm)
over nominal strip length.
6.13 Coil Set — Maximum of 0.020" (0.508 mm) over
the nominal strip length. This does not include material
thickness.
6.14 Cross Bow — Shall not exceed the following
dimensions:
No. of Leads Maximum Cross Bow
52—100 0.006" (1.52 mm)
132—164 0.010" (0.254 mm)
196—244 0.012" (0.305 mm)
7 Sampling
Sampling will be determined between supplier and
purchaser.
8 Packaging and Marking
8.1 Packaging — Leadframes must be packaged in
containers designed and constructed to prevent damage
and contamination.
8.2 Marking — The outer containers shall be clearly
marked identifying the user stock number, user
purchase order number, drawing number, and vendor
lot numbers within the carton.