Lead ame designs achieve tighter tolerances

Lead frames are used in the semiconductor assembly process. They are essentially thin layers of metal that connect the wiring from tiny electrical terminals on the semiconductor surface to the large-scale circuitry on electrical devices and circuit boards. In lead frame design, one size does not always fit all, and very often, demand is for customized features, designs that enhance electrical and thermal properties, and specific cycle times.

The micrometal Group has developed a next-generation photo-chemical etching (PCE) process well-suited for lead frame production. The process allows manufacturers to make innovatively designed lead frames with tight tolerances repeatably and accurately concerning miniaturization and weight-saving trends.

“We etch simple or sometimes more complex lead frames from metal and alloys that demonstrate a very low expansion rate at room temperature. These low thermal expansion alloys have found use in modern applications which require joining metal to glass or ceramics and preventing associated problems within the joint area,” said Jochen Kern, head of sales and marketing at the micrometal Etching Group.

Lead frames can be highly complex and fragile. In many instances, geometric complexity, exacting tolerances, and precision requirements limit the technology capable of producing certain lead frames. When stamping lead frames, complex designs often require complex mold tools, which increases costs and lead times.

PCE is agnostic to the geometry and tool complexity. It can produce lead frames with tighter tolerances and finer detail than stamping, minimal to no metal degradation and deformation, and little to no likelihood of burrs or defects. Failure rates are minute, and unlike stamping, every lead frame produced is absolutely flat, which is a vital prerequisite. micrometal’s tight tolerance manufacturing processes are appropriate for numerous lead frame applications and ideally suited to high lead/pin count and ultra-fine pitch lead frame manufacture in high volumes DW

“micrometal’s unique process can achieve dimensional tolerances as low as ±0.005 mm, small feature sizes of 25 microns, a minimum hole diameter of 80% of the material thickness, and single-digit micron tolerances repeatably. Compare this with traditional chemical etching, which can only achieve the smallest feature size of 100 microns, and the smallest hole diameter is a factor of 1 to 2 when compared to material thickness. Our PCE process opens up numerous impossible design opportunities when manufacturing lead frames,” said Kern.

Micrometal | www.micrometal.de