EnerChip™ Bare Die Batteries

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DS-72-41 Rev06

Page 9 of 13

Preliminary

BARE DIE DELIVERY OPTIONS

EnerChip bare die applications often require custom procedures and significant variation exists among package

vendors and assembly equipment, making specific guidelines difficult. Contact Cymbet Application Engineering

to review handling, wirebonding, bumping, and assembly guidelines.

Bare die undergo the following screening procedures prior to leaving the manufacturing facility:

• Electrical test to ensure the cell is not shorted, open, and is within the specification limits of cell resistance.

• MIL-STD-883 optical inspection.

BARE DIE HANDLING GUIDELINES

• When unpacking, storing, inspecting, or handling bare die EnerChips, all operations should be performed

in a Class-1,000 (or better) clean room - ISO 6 equivalent.

• When removing die from waffle packs, use the minimum downward force possible with the handling

mechanism.

• Handling and insertion forces need to be kept to a minimum to reduce damage to the device materials.

• Tool recommendations: Use pick-and-place tool having a “soft” tip, e.g., rubber or other pliable material.

• EnerChips are sensitive to electrostatic discharge (ESD) and should always be handled in an ESD-

controlled environment.

• EnerChips should be stored in a humidity-controlled environment to prevent excess moisture from

penetrating the EnerChip.

• Never use tweezers (or other mechanical means) on the film surface of the bare die. When using

mechanical means (vs. vacuum pick and place tool) always pick up EnerChip bare by the outside edges of

the part.

DIE BUMPING AND WIREBONDING

EnerChip bare die have bond pads that are suitable for either wirebonding. The pad structure on the EnerChip

bare die described in this datasheet are designed for wire bonds. With only two bond pads on an EnerChip die,

gold stud bumping is not suggested as it would yield a mechanically unsound configuration.

Bond pads are made of aluminum with a small amount of silicon and copper and therefore either gold or alumi-

num wires may be attached to the bond pad.

Standard wirebond machine and process settings are generally applicable when wirebonding to EnerChip die.

When placing EnerChip die onto the die attach material, use the minimum downward force possible. Ensure

there is a uniform coating of die attach material on the substrate (i.e., no voids or gaps) and that the die attach

material extends to the edge of the EnerChip die during die placement.

Recommended wirebond process time and temperatures are as follows:

Die Attach Epoxy Cure

190°C +/- 10°C for 1.5 hours

Wirebond

Pre-heat:

190°C

Wirebond:

200°C

Post-heat:

190°C

Package Epoxy Cure

175°C +/- 10°C