Need a hermetic lid? WAM has a cover for you.
The following data suggests situations that could best utilize WAM's hermetic lid options, which include Combo-Lid®, Micro-Lid™, Solder Reflow-Lid™, and Seam Seal-Lid™. For information about Visi-Lids™ see the link on the right.
COMBO-LID ® or Frame Lid Assembly
Attributes
The COMBO-LID ® continues to be a leading choice for hermetically sealing electronic packages. The base material is either Kovar™ or Alloy 42, which is electroplated with nickel to ensure a clean, particulate free surface. The lids are then electroplated with a gold flashing and subsequently tack welded to a solder preform. The nickel electroplate layer serves as a very effective barrier to corrosion, while the gold electroplate layer provides a readily solderable surface.
Technical Information
| Two Layer Plating |
Layer |
CTE
(µin/in/oC) |
Layer
Thickness |
Kovar™ |
4.9 |
Balance |
Ni |
13.3 |
50-350 µin |
Au |
14.2 |
25-100 µin |
80Au20Sn |
15.9 |
2.1 mils |
Plating and Clad properties can be modified to meet specific needs.
Four Layer Plating |
Layer |
CTE
(µin/in/oC) |
Layer
Thickness |
Kovar™ |
4.9 |
Balance |
Ni |
13.3 |
50-350 µin |
Au |
14.2 |
25-100 µin |
Ni |
13.3 |
50-350 µin |
Au |
14.2 |
25-100 µin |
80Au20Sn |
15.9 |
.0021 mils |
|
Sizes
Williams can provide numerous sizes to fit your needs. We have over 7,000 tool sets for frames and lids. Typical sizes range from .120 square inches to 2.50 square inches. WAM recommends that the OD of the COMBO-LID ® be 0.025" less than the OD of the package seal ring, while the ID of the COMBO-LID ® is 0.045" larger than the ID of the package seal ring.
Typical Tolerances:
Lid
X-Y dimensions: ± 0.003"
Thickness: ± 0.001"
Flatness: within 0.001" (Lids < 0.500)
within 0.002" (Lids > 0.500)
Burr: less than 0.001"
Frame
X-Y dimensions: ± 0.003"
Thickness: within 0.003"
Composition: 80Au20Sn with total impurities less than 150 ppm
Assembly
Weld alignment: ± 0.005"
Weld Spatter ± 0.003
Electroplated Layers
Nickel - The nickel layer is electroplated to a customer's desired thickness with a CpK of 1.33.
Gold - The gold layer is electroplated to a customer's desired thickness with a CpK of 1.00.
Recommendations
A COMBO-LID ® is typically used on ceramic packages.
Micro-Lid™
Attributes
The MicroLid™ is a cost effective alternative to the COMBO-LID ® for smaller lids, typically less than 0.2" by 0.2". The precious MicroLid™ can eliminate a large percent of the precious metal in the package. MicroLids™ are produced using cladding technology to mechanically bond a solid AuSn preform onto Kovar™ or Alloy 42. The parts are then stamped and an optional gold plating layer can be added to produce a fillet.
Technical Information
Layer |
CTE
(µin/in/oC) |
Layer
Thickness |
Kovar |
4.9 |
Balance |
Ni |
13.3 |
50-350 µin |
Au |
14.2 |
25-100 µin |
80Au20Sn |
15.9 |
.0008-.0016 mils |
Plating and Clad properties can be modified to meet specific needs.
Sizes
Williams can provide numerous sizes to fit your needs. We have a large library of available tools. For cost effectiveness, the MicroLid™ is typically used for packages with dimensions of .200 by .200 or smaller.
Typical Tolerances:
Lid
X-Y dimensions: ± 0.003"
Thickness: ± 0.0003"
Flatness: within 0.001"
Recommendations
MicroLids™ are a cost effective alternative to the COMBO-LID ® when dealing with smaller packages. The MicroLid™ offers the same processing temperatures as a COMBO-LID ®, with the added benefit of lower cost. The hermeticity of the package is maintained with the AuSn precious layer.
Solder Reflow-Lid™
Attributes
The Solder Reflow Lid is a cost effective alternative to a COMBO-LID® for smaller lids, typically less than 0.2" by 0.2". Solder Reflow Lids are available with non-precious solders. The non-precious Solder Reflow Lid eliminates any of the precious metals in the package. Cladding a corrosion resistant solderable metal onto a controlled thermal expansion alloy typically produces the Solder Reflow Lid. The parts are then stamped to specification.
Technical Information
Layer |
CTE
(µin/in/oC) |
Layer
Thickness |
Kovar |
4.9 |
Balance |
Ni |
13.3 |
50-350 µin |
|
Solder Layer - See recommendations below |
Sizes
Williams can provide numerous sizes to fit your needs. We have a large library of available tools. For cost effectiveness the Solder Reflow Lid is typically used for packages with dimensions of .200 X .200 smaller.
Typical Tolerances:
Lid
X-Y dimensions: ± 0.003"
Thickness: ± 0.0003"
Flatness: within 0.001"
Recommendations
The Solder Reflow Lid is a very cost effective alternative to a COMBO-LID® when dealing with smaller packages. Solder Reflow Lids with 86Pb8Bi4Sn1Ag1In have a melting range of 250°-278° F. Therefore a furnace profile similar to 80Au 20Sn (Eutectic 280) can be used. For situations calling for a lead free solder, 95.Sn 3.5Ag 1.9Sb (which has a melting range of 218°-226° F) is a viable solution.
Seam Seal-Lid™
Attributes
Williams manufactures a Seam Seal Lid. The Lids are either Kovar™ or, Alloy 42, with an exceptionally low particulate Ni plating. The customer then places the lid over the electronic package and continuously welds along the perimeter to form a hermetic seal.
Technical Information
Layer |
CTE
(µin/in/oC) |
Layer
Thickness |
Kovar |
4.9 |
Balance |
Ni |
13.3 |
50-325 µin |
Williams offers Electroless and Electrolytic Nickel plating.
Sizes
Williams offers Seam Seal Lids in a variety of sizes and configurations to meet your needs. We have a large library of available tools. Typical dimensions for the lids range from .250” square to .060” square.
Typical Tolerances
Lid
X-Y dimensions: ± 0.003"
Thickness: ± 0.001"
Flatness: within 0.001" (Lids < 0.500) and within 0.002" (Lids > 0.500)
Recommendations
Seam Seal Lids offer a non-precious packaging alternative to the MicroLid™ and COMBO-LID®. The Seam Seal Lid undergoes localized heating in the welded perimeter only, allowing one to package more heat sensitive electronics.
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