WILLIAMS Advanced Materials 

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 perform. The nickel electroplate layer serves as a very effective barrier to corrosion, while the gold electroplate layer serves to provide a readily solderable surface  

Layer

CTE
(µin/in/^oC)

Layer
Thickness

Layer

CTE
(µin/in/^oC)

Layer
Thickness

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.

Lid
X-Y dimensions: ± 0.003"
Thickness: ± 0.001"
Flatness: within 0.001" (Lids < 0.500) and
within 0.002" (Lids > 0.500)
Burr: less than 0.001"

We recommend a typical clip force of 0.9-2 lbs. Clip pressure varies depending on lid size, preform thickness, lid flatness, and seal-ring flatness. Typical sealing profiles allow for 2-5 minutes above 280 C (melting temperature) with a peak temperature not exceeding 340 C in dry nitrogen, or hydrogen.      

X-Y 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.    

A COMBO-LID^® is typical used on ceramic packages

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.

Layer

CTE
(µin/in/^oC)

Layer
Thickness

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.

Lid
X-Y dimensions: ± 0.003"
Thickness: ± 0.0003"
Flatness: within 0.001"

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.

Attributes
Williams manufactures a Seam Seal Lid. The Lids are either KovarTM 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.

Layer

Williams offers Electroless and Electrolytic Nickel plating.

Kovar™

Ni™

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.

Lid
X-Y dimensions: ± 0.003"
Thickness: ± 0.0003"
Flatness: within 0.001"

Seam Seal Lids offer a non-precious packaging alternative to the MicroLidTM and COMBO-LID®. The Seam Seal Lid undergoes localized heating in the welded perimeter only, allowing one to package more heat sensitive electronics.

Attributes
With solder coverage controlled right up to the lid edge, Williams' Solder Reflow-Lid™ easily passes gross leak tests and has set the benchmark within the industry.

Layer

(Solder Layer - See recommendations below)

Kovar™

Ni™

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” or smaller.

Lid
X-Y dimensions: ± 0.003"
Thickness: ± 0.0003"
Flatness: within 0.001"

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 as a melting range of 218°-226° F is viable solution. Customized solders are available to meet your requirements.