Overview

An etched heat spreader is a flat metal plate with channels, pockets, cavities or through-features formed by photochemical etching, used to spread and remove heat from chips, modules and power devices. Instead of machining, the plate is laminated with resist, exposed, developed and etched, so recessed features are dissolved into the surface without cutting force. This leaves the plate flat and stress-free — a critical requirement where the spreader must sit in intimate contact with a die or a heat sink and maintain a thin, uniform thermal interface.

Because etching is chemical and tooling-free, an etched heat spreader can carry features that are hard or expensive to machine: thin serpentine channels, fine pin arrays, pockets with a flat floor, and precise through-holes for fasteners, all on one plate. Materials are chosen for thermal conductivity and expansion match — copper C1100/C1020, aluminum 6061/1100, stainless steel 304, Alloy 42, kovar and molybdenum, from 0.1 mm to 2.0 mm thick. The result is a thermally efficient plate with controlled flatness, ready for chip-level, module-level and optoelectronic cooling.

Parameter Window

• Available Materials: copper C1100/C1020, aluminum 6061/1100, stainless steel 304, Alloy 42, kovar, molybdenum
• Material Thickness Range: 0.1–2.0 mm
• Tolerance: ±0.02 mm on profile, 0.05 mm/100 mm flatness
• Minimum Feature: 0.1 mm channel width and 0.15 mm wall
• Surface Options: electroless Ni/Au, black oxide, passivated, bright
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Thermal Design Review — Convert the channel, cavity and hole layout to artwork, and confirm depths, wall widths and fastener positions.
2. Material Selection — Choose the alloy for conductivity and expansion match: copper for conductivity, kovar or Alloy 42 for die CTE matching.
3. Cleaning & Lamination — Degrease both sides and laminate dry film under controlled pressure so channel areas sit over clean metal.
4. UV Exposure — Expose through registered films so channels, pockets and holes align with the plate datum and each other.
5. Development — Wash out unexposed resist to open the thermal features, then inspect for residual resist before etching.
6. Etching — Etch the channels and cavities in matched chemistry, controlling depth and floor flatness by time and temperature.
7. Stripping & Finishing — Remove the resist, neutralize, then apply Ni/Au plating, black oxide or passivation as specified.
8. Inspection — Verify channel depth, floor flatness, overall flatness and thickness under vision and CMM before packaging.

Core Advantages

1. Stress-free flatness: Chemical removal applies no cutting force, so the plate stays flat and distortion-free after etching.
2. No tooling cost: Each channel layout is a new film set, so prototypes and revisions start without CNC programming or dies.
3. Fine thermal features: Channels down to 0.1 mm and thin walls are etched cleanly, beyond what machining can reach economically.
4. Full thermal conductivity: The base material is not work-hardened or stressed, preserving its intrinsic thermal performance.
5. Batch consistency: Photographic transfer keeps every plate identical, supporting repeatable thermal performance across a run.
6. Material flexibility: Copper, aluminum, stainless, Alloy 42, kovar and molybdenum run on the same line for varied thermal needs.

Typical Applications

• Chip heat spreaders: Flat copper plates with etched pockets for die-attach and heat spreading in semiconductor packages.
• Power module baseplates: Channel and pocket plates for IGBT and power module cooling.
• Laser diode mounts: Thin kovar or Alloy 42 plates with etched cavities for laser diode submounts.
• LED substrates: Etched copper or aluminum plates for high-power LED thermal management.
• RF and microwave carriers: Flat plates with etched cavities for RF amplifier and MMIC mounting.
• Vapor chamber components: Etched plates that form the channel and wick structure of vapor chambers.

Design Notes & Process Considerations

1. Flatness callout: State flatness per 100 mm and total flatness, since die and heat sink contact demands a uniform interface.
2. Conductivity versus CTE: Copper maximizes conductivity but Alloy 42 or kovar matches die expansion; choose for the solder or attach interface.
3. Channel depth and floor: Specify depth and floor flatness for pockets; etched floors are controlled by etch time and chemistry.
4. Wall width limits: Keep walls at 0.15 mm minimum relative to thickness, or undercut will thin and distort the wall.
5. Surface finish: Name the plating or passivation, since Ni/Au and black oxide affect both emissivity and solderability.
6. Through-features: Combine pockets and through-holes on one plate with shared registration to keep fastener and channel alignment tight.