Etched Lids & Covers

A step lid must have a precise, quality fit, as anything else will cause difficulty in welding. PEI's expertise in photochemical etching gives us a unique understanding of the process and its capabilities. PEI has been etching step lids and flat lids for seam-weld able microelectronic packages for over 30 years, bringing our customers the best quality lids available in the market at competitive prices. Both major package manufacturers and hybrid manufacturers purchase lids to a given print or by specifying the package to which the lid will be welded. PEI can produce lids in any quantity, from one to millions, in thicknesses up to 0.05 in. (1.27 mm).

If a lid is not listed on PEI's standard tooling list, there will be a one-time tooling charge. PEI may absorb tooling costs on volume orders. Contact PEI's sales department for a copy of our current tooling list.

The standard base material is etching-grade iron-nickel-cobalt alloy, per MIL-I-20311C, Class 1 (ASTM designation F-15). PEI will manufacture lids from other alloys, such as Ni 200, stainless steel, cold rolled steel, etc., to meet customer specifications.

PEI produces all lids to tight tolerances to ensure a precise fit on customer packages. PEI will design a tight-fitting lid upon receiving dimensions and specifications from customers, and will guarantee the proper fit. For 0.010 in. (0.254 mm) to 0.015 in. (0.381 mm) lids, the typical tolerance is +/- 0.003 in. (0.076 mm) on features and +/- 0.001 in. (0.025 mm) on the flange. Flatness will be held to 0.002 in. (0.05 mm) per inch (25.4 mm). On lids 0.020 in. (0.5 mm) or greater, typical tolerances vary due to material thickness. PEI can also achieve tighter tolerances, contact our sales department for details.

Plating and finishing options available from PEI include Gold plate per MIL-G-45204B Type III, Class I or II (50 or 100 micro inches minimum), Electrolytic nickel per QQ-N-290, or Electroless nickel per MIL-C-26074. Selective plating is available upon request.

All dimensions are inspected per MIL-STD-105D at 1.0% AQL. All lids are guaranteed by PEI to meet the requirements of MIL-STD-883. Bake and bend tests are performed to ensure proper adhesion of plating. PEI will perform a 100% inspection on all dimensions and will provide test data at an additional charge. PEI will supply a cover with no tab protruding at an additional charge. PEI can also supply an etched and stamped cover for maximum uniformity of the sealing area. Please contact our sales department for more information.

1. There shall be no etch pits in the seal flange area. Full thickness area of the lid shall have less than three etch pits equal or greater than 0.008 in. (0.203 mm) diameter for 0.015 in. (0.381 mm) thick lids, and 0.006 in. (0.152 mm) diameter for 0.010 in. (0.254 mm) tick lids..
2. There will be no tabs greater than 0.002 in. (0.05 mm).
3. There will be no burrs greater than 0.0005 in. (0.0127 mm).

PEI's improved etched edge increases welding yeilds by creating a better fillet of plating between the package and the lid. This improved edge also prevents microcracking during sealing.

Typical Flange Edge PEI Flange Edge

All lids are typically packaged individually in ESD-safe bags and placed in a foam-lined container marked with purchase order number, part number, lot number, quantity, and date. PEI can also design and implement custom packaging, often adding security and lowering risk of damage.