Copper Wire Ready for Automotive AEC Requirements?

Wire bonding is widely used in the

microelectronics industry to assemble

the vast majority of semiconductor

packages, electrically connecting Aluminum (Al) bond pads on the IC

chips to the corresponding bond pads on the plastic or lead frame chip carriers. The Industry has short listed several common Bond wires which

usually consist of good conductor

metals such as Gold (Au), Aluminum

(Al), and Copper (Cu).

Gold has been the most preferred

material because of its long successful history, extensive

reliability data, resistance to surface corrosion and wire ductility during the wire bonding process.

However, as the price of gold is currently in a global volatile market, the microelectronics industry has once

again been presented with cost driver

opportunities for bonding wire

material for High Reliability Applications such as Automotive Applications.

Many companies have looked at bare

Copper wire as a viable replacement

option for Gold wire, however many

barriers were encountered using

conventional Copper wire in advanced

packaging and assembly. The main

industry shortcomings were; reduced lifespan of Copper wire (productivity and reliability), necessity to use wire surface oxidation which limited shelf/bonder life and hard ball

formation at the tip of the bonding wire.

Cu wire presents challenges in meeting

reliability standards for Automotive

AEC requirements.

The discussion will cover the influences of various wire types and mold compound interactions on the

package reliability for Automotive AEC

requirements. Extended reliability of

Cu wire types will be investigated after unbiased/biased (HAST) and high

temperature storage life (HTSL) at 150C, 175C aging temperatures. Failure

mechanisms will be presented after

observations of extended reliability

tests on bonded Cu wire samples.

Future engineering work should be

focused on the utilization of best

known methods (BKM) and predictions of

Cu wire reliability testing to understand the initial failure point risk in Automotive device packaging.