Selectively Plated Lid – Combo Lid™
Materion Advanced Materials Technologies and Services is a leading choice for hermetically sealing electronic packages and is well-known for its fully plated lid and Combo-Lid™ solutions.
With the aim of reducing gold content on hermetic lids, Materion has developed the Selectively Plated Lid. The rise in gold prices has meant a constant struggle in the supply chain to maintain profit lines. In an effort to provide smarter, simplified solutions to their customers, Materion’s patented Selectively Plated Lid will deliver a superior performance lid while providing flexibility to customers in selecting the right configuration for their specific applications.
Like the fully plated lid and the Combo-Lid™, the Selectively Plated Lid uses Kovar™ or Alloy 42 as its base material. The Kovar is electroplated with nickel to ensure a clean particulate-free surface. The lids are electroplated with a gold flashing and a solder preform is tack-welded to the lid. The nickel electroplated layer serves as an effective barrier to corrosion. The gold electroplate layer provides a readily solderable surface.
Materion’s Selectively Plated Kovar Lid is selectively plated with nickel and gold including the sides of the lids. Nickel on the inner portion of the solder side of the lid helps to keep the solder within the gold-plated zone. To reduce cost, no gold is required on the opposite side of the lid.
Fully Plated Kovar Lid
Selectively Plated Kovar Lid
Alternatively, the Selectively Plated concept also enables other solder alloys to be tack-welded onto the lid as a Selectively Plated Combo-Lid™.
The Selective Plated Lid is now ready to accept other solder alloys that would wet on gold. The nickel in the middle of the lid will not allow solder wetting, thus good solder braze is formed between lids and ceramic packages. This design also provides an opportunity to increase solder volume to optimize sealing.
The illustration below shows successfully sealed units.
Selective Plated lid (Ni in the middle & Au for soldering.