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SEMI G58-94 © SEMI 1994 2 3.8 foreign material — an adheren t p article t hat is not parent material of t he compon e nt. Adherence means that the particle cannot be removed by an air or nitrogen blast at 20 ps i. 3.9 gl…

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SEMI G58-94 © SEMI 19941
SEMI G58-94
SPECIFICATION FOR CERQUAD PACKAGE CONSTRUCTIONS
1 Preface
1.1 Purpose — This specification defines the
acceptance criteria for Cerquad package components
and includes requirements for the base, leadframe,
window frame, cap and sealing glass materials.
1.2 Scope — This specification applies to all Cerquad
packages which have a leadframe sandwich between
two ceramic pieces — the base and the window frame
— and sealed by glass, and a cap with a similar glass
seal.
NOTE 1: The base, leadframe and window frame may be
purchased as separate components or as a completed
assembly.
1.3 Units — U.S. Customary (inch -pound) or metric
(SI) units may be used at the customer’s discretion.
This specification uses U.S. Customary units as the
prime unit.
NOTE 2: In the figures only U.S. Customary units are shown.
2 Applicable Documents
2.1 Order of Precedence — To avoid conflicts, the
order of precedence when ordering package
components shall be as follows:
Purchase Order
Customer’s Component Drawings
This Specification
Referenced Documents
2.2 Referenced Documents
2.2.1 SEMI Specifications
SEMI G21 — Plating Integrated Circuit Leadframes
SEMI G23 — Measuring the Inductance of Package
Leads
SEMI G24 — Measuring the Lead-to-Lead and Loading
Capacitance of Package Leads
SEMI G25 — Measuring the Resistance of Package
Leads
Compilation of Terms
2.2.2 JEDEC Specifications
1
Pub. No. 95 — Registered and Standard Outlines for
Semiconductor Devices
1 JEDEC, 2001 Eye Street N.W., Washington, DC 20006.
2.2.3 Military and Federal Specifications
2
MIL-STD-105 — Sampling Procedures and Tables for
Inspection by Attributes
MIL-STD-883 — Test Methods and Procedures for
Microelectronics
MIL-STD-1835 — Microcircuit Case Outlines
MIL-G-45204 — Gold Plating — Electrodeposited
MIL-M-38510 — General Specification for
Microcircuits
3 Selected Definitions
3.1 blister (bubble) metallization — an enclosed
locallized separation of the metallization from its base
material (such as ceramic or another metallization layer
component) that does not expose the underlying layer.
3.2 burr — an adherent fragment of parent material at
a component edge. In leadframes, the metal burr, due to
the stamping operation, may be in the horizontal or
vertical direction to the surface. In ceramic packages,
this type of characteristic is called a fin.
3.3 camber (ceramic) — arching o f a nominally flat
ceramic body.
3.4 chip — region of material missing from a
component (e.g., ceramic from a package, or solder
from a preform). The region does not progress
completely through the component and is formed after
the component is manufactured. Chip size is defined by
its length, width and depth from a projection of the
design planform. Also called chipout. (See Figure 1.)
3.5 crack — a cleavage or fracture that extends to the
surface of a semiconductor package or solder preform.
The crack may or may not pass through the entire
thickness of the package or preform.
3.6 critical seal area — on a semiconductor package,
the area bounded by the shortest nominal design
distance from the largest cavity, usually the wire bond
cavity, to the edge of the package or ceramic layer
forming the seal area. (See Figure 2.)
3.7 fin — on a ceramic package or cap, a fine
feathery-edged projection of parent ceramic material on
the corner of the ceramic body.
2 Military Standards, Naval Publications and Form Center, 5801
Tabor Avenue, Philadelphia, PA 19120
SEMI G58-94 © SEMI 1994 2
3.8 foreign material — an adherent particle that is not
parent material of the component. Adherence means
that the particle cannot be removed by an air or nitrogen
blast at 20 psi.
3.9 glass flow — on a semiconductor package or cap,
the heating process which just removes all the screen
printing mesh marks in the sealing glass when viewed
at 10× magnification.
3.10 glass void — the absence of a sealing glass layer
from a designated area.
3.11 metallization void — the absence of a clad,
evaporated, plated or screen-printed metal layer or
braze from a designated area.
3.12 non-critical seal area — on a semiconductor
package that uses a lid, cap, or cover to effect the seal,
the area of the sealing surface outside the critical
sealing area. (See Figure 2.)
3.13 overhang — on a semiconductor package, the
horizontal extension of the sealing glass past the
vertical wall of a cavity cut into the ceramic layer on
which the glass is printed. (See Figure 3.)
3.14 peeling (flaking) — any separation of a plated,
vacuum deposited, or clad metal layer from the base
metal of a leadframe, pin, heatsink, or seal ring, from an
underplate, or from a refractory metal on a ceramic
package. Peeling exposes the underlying metal.
3.15 projection — on a semiconductor package
(plastic or ceramic), leadframe or preform, and
irregularly raised portion of a surface indiginous to the
parent material.
3.16 pullback — on a semiconductor package, the
linear distance between the edge of a cavity cut into a
ceramic layer and the first measureable glass or
metallization layer interface coated onto the top surface
of that layer. The total pullback may be the result of the
high temperature processing required to manufacture
the package or to coat the surface. It may also be the
result of design considerations. (See Figure 3.)
3.17 rundown — on a semiconductor package, the
linear distance from the upper surface of a ceramic
cavity layer to the bottom point of the overhang into the
cavity, of a sealing glass or metallization layer that has
been screened onto that surface. (See Figure 3.)
4 Ordering Information
Purchase orders for cerquad packages and caps
furnished to this specification shall include the
following items:
4.1 Package description
4.2 Current drawing revision detai ling
All dimensions
Type and color of ceramic
Type and thickness of sealant glass
Leadframe material type and design
Type and thickness of metallization in the lead
bond area
Type and thickness of external lead plating, if
applicable
Type and thickness of die attach metalization
4.3 Vendor certification requirements
4.4 Any additions to, or variations from, this
specification
5 Dimensions
The component described in this specification shall
produce packaged devices that conform to the outline
dimesnions and lead numbering for Cerquad Package
Constructions detailed in: JEDEC Publication 95; EIAJ;
MILSTD1835. Package manufacturing tolerances shall
be agreed between vendor and customer.
6 Materials
The definitions, defect criteria, and functional tests
described in this specification relate to package
components made with the following materials:
6.1 Base, Window Frame, and Cap
6.1.1 Material
6.1.1.1 Alumina — Content to be 90% minimum, or
6.1.1.2 Beryllia — Content to be agreed between
vendor and customer.
6.1.2 Color
6.1.2.1 Alumina — Black, dark brown, or violet.
6.1.2.2 Beryllia — White.
6.2 Sealant — A solder glass suitable for hermetic
sealing shall be specified.
6.3 Die Attach Pad Metallization — Gold or any other
suitable material shall be specified.
6.4 Leadframe
6.4.1 Base Material
6.4.1.1 Thickness — Shall be specified.
6.4.1.2 Composition — Iron-Nickel-Cobalt alloy per
MIL-M-38510, Type A or Iron-Nickel alloy per MIL-
M-38510, Type B shall be specified.
SEMI G58-94 © SEMI 19943
6.4.2 Finish — Lead bond areas.
6.4.2.1 Metallization — Aluminum.
6.4.2.1.1 Thickness — 100 – 600 microinches (0.0025
– 0.015 mm).
6.4.2.1.2 Coverage — Total coverage for a distance of
0.030" (0.762mm) minimum as measured from the lead
tip. Maximum length is defined by the lead bond cavity
size.
6.4.2.1.3 Composition — 99.4% minimum for clad
aluminum, 99.99% minimum for vapor deposited
aluminum.
6.4.2.2 Metallization — Gold.
6.4.2.2.1 Thickness — 50 – 225 microinches (0.0013 –
0.0057mm).
6.4.2.2.2 Coverage — See paragraph 6.4.2.1.2.
6.4.2.2.3 Composition — See SEMI G21 and MIL-G-
45204.
6.4.3 Leadframe Finish — External areas (if
specified).
6.4.3.1 Metallization — Gold (see Section 6.4.2.2).
7 Defect Limits
The following defects shall be rejected if the limits
shown are exceeded:
NOTE 3: The criteria apply to purchased pre-assemblies or,
where applicable, to units assembled by the customer to
process conditions agreed between vendor and customer.
7.1 Ceramic Components
7.1.1 Cracks — Not allowed.
7.1.2 Chips — See Figures 1 and 2.
7.1.2.1 Corner Chips — 0.030" (0.762 mm) × 0.030"
(0.762 mm) × 25% of package element thickness.
7.1.2.2 Edge Chips — 0.060" (1.524 mm) × 0.030"
(0.762 mm) × 25% of package element thickness.
7.1.2.3 Critical Seal Area — Chips must not reduce
the critical seal path length, at any point, to less than
one-half the nominal design dimension. No more than
four chips are allowed in this area regardless of loss of
seal length.
7.1.3 Burrs, Projections (Fins), and Blisters
7.1.3.1 Base, Window Frame, and Cap — 0.005"
(0.127 mm) maximum allowable dimension or greater
than 0.003" (0.076 mm) height.
7.1.3.2 Die Attach Surface — 0.001" (0.025 mm)
maximum above the metallization surface excluding a
zone, 0.010" (0.25 mm) wide, around the periphery of
the cavity maximum allowable dimension is 0.005"
(0.127 mm).
7.1.4 Camber — Shall be specified on the component
drawing.
7.2 Glass Sealant
7.2.1 Chips and Voids — 0.010" (0.254 mm)
maximum allowable dimension, with exposed or
covered ceramic. No more than four chips or voids are
allowed in the critical seal area. These defects must also
meet the requirements of Table 1 in Section 7.2.2.4.
7.2.2 Glass Misalignment (after glass flow) — See
Figure 3.
7.2.2.1 Glass Overhang — 0.15" (0.381 mm)
maximum extension from the ceramic edge.
7.2.2.2 External Rundown — 50% of component
thickness maximum.
7.2.2.3 Rundown into Lead Bond Cavity — 0.010"
(0.254 mm) maximum extension from the top surface
of the cavity.
7.2.2.4 Pullback — See Table 1.
Table 1 Maximum Allowable Pullback
External 0.015" (0.381 mm)
Internal 0.101" (0.254 mm)
NOTE 3: Glass pullback, at any point, shall not reduce the
critical seal path width to less than one-half the designed
width. (See Figure 2.)
7.2.2.5 Foreign Material — 0.020" (0.508 mm)
maximum allowable dimension but 0.010" (0.254 mm)
in the critical seal area, with no more than four sites
allowed and a minimum separation of 0.030" (0.762
mm) between sites.
7.3 Die Attach Cavity Metallization — Excluding a
0.010" (0.254 mm) wide zone around the periphery of
the cavity, the following criteria apply:
7.3.1 Foreign Material, including Glass Splatters —
no more than four areas with 0.005" (0.13 mm)
maximum dimension or greater than 0.001" (0.025 mm)
height.
7.3.2 Metallization Lumps — No more than four
allowed. If the metallization is Gold and eutectic Gold-
Silicon die attach is to be used, then the lumps may not
exceed 0.010" (0.254 mm) in diameter and 0.005"
(0.127 mm) height. If eutectic bonding is not used, then
the lumps will be treated as foreign material per Section
7.3.1