Thermosonic Gold to Gold Interconnect (GGI) Flip Chip Bonding for 7mm2 Die

Flip Chip ultrasonic gold to gold interconnect (GGI)

has provided a lead free, no clean, process solution

for devices with bump counts under 100 for the past

five years. The proven reliability and manufacturing

cost savings of ultrasonic GGI bonding has now

expanded to include large die sized up to 7mm2 with

bump counts up to one hundred.

The bonding accuracy of the GGI process is +/- 10

μm. The availability of a voice coil motor with 100N

load capability and improved horn design has

allowed for the performance improvement in

thermosonic GGI flip chip bonder equipment for

large die size with high I/O for device packaging.

GGI CSP packaging is used for CMOS sensor,

MEMs, RF, memory, and HBLED devices.

Thermosonic GGI bonders use a built in monitoring

function for each die bond. The bump collapse

height, bond impedance, die X-off, die Y-off, and θ

can be “mapped” for each die bond location in real

time. The bond map data is stored as a text log file

for easy access by downstream test operations.

Gold bonds provide superior bond strength because

of the monolithic bond structure of the gold material.

Gold bonds also have superior electrical high

frequency performance and low resistance when

compared to solder or conductive interconnect

processes. Package size reductions are achieved with

flip chip thermosonic GGI process when compared to

wire bonding. The robust GGI thermosonic process

reliably handles gold bump diameter of 60 μm ~100

μm in high volume manufacturing.

The GGI process capability has allowed die size

reductions up to 70% when compared to wire

bonding process. 30% less gold material is used

compared to gold wire bonding since the “wire

stitch” is eliminated leaving the gold ball for the GGI

interconnect.

Flip Chip thermosonic GGI process can bond die

with thickness as thin as 100 μm. This has been an

important benefit for mobile device packaging where

low profile devices are critical to the market.

Low cost organic substrate materials and embedded

passive LTCC substrates are used in flip chip

thermosonic GGI device manufacturing. Because the

GGI thermosonic uses solid phase micro welding of

the die to the substrate, relatively low bonding

temperatures <200° C are used in the bond profile.

Thermosonic GGI flip chip process provides fast die

attach process time <500msec, a clean process, at low

temperature with precision.