Electrical Connector

1. Theory
2. Flip chip
3. BGA

Various electrical connector configurations can be made using Particle Interconnect, a few are shown.

Theory

Particle Interconnect via

Connecting two conducting surfaces together.

Particle closeup	Connector closeup

SEM's of contact surface

Tin-Lead solder over Nickel coated particles.

22x magnification with 88x zoom view.

Flip chip

Particle Interconnect - Hughes Aircraft 1988 - 1989

50,000 die joint production test venture.

Before burned-in:

• No bump deformation.
• Die Sn/Pb 3/97, socket Au 100, load 1 gm/mil² pad to socket. Burned-in 125 ° C for 168 hours. Particles milled into gold ceramic ink and fired onto ceramic substrate. (Depression in center of bump is aluminum die pad covered by protective passivation layer.)

50x bumped chip before pressing against PI gold thick film.	500x bump before contacting PI.

After burned-in:

• No bump deformation.
• PI/gold bonded to tin/lead bump and was ripped off substrate. Resulting in using nickel as higher strength Particle Interconnect bond layer in future test socket/temporary contact usages and other metal combinations in permanent usages.

50x bumped chip after pressing against PI gold thick film metal matrix with 1 gm/mil2 load.	500x bump after contacting PI, metal matrix is on bump.

Particle Interconnect - Hughes environmental test die

Particle Interconnect removable MCM die socket.

100% of 500 die lot survived 4x Mil-Std-883C.

1. Particle Interconnect with both adhesive and mechanical hold-down of chips while accumulating 4 runs of:
• 168 hours (672 hours total) 125 ° C for burn-in (other test passed are continuous 125 ° C),
• 500 cycles (2,000 cycles total) -55 to +125 ° C fast ramp MIL-STD-883C shock test,
• 24 hours (96 hours total) in salt/fog corrosion test,
• 24 hours (96 hours total) HAST (Highly Accelerated Stress Testing) pressure chamber (30 psi, +125 ° C pressure pot),
• Results in 50,000 die lot test prior to transfer into production.
2. 96/4 Pb/Sn reflowed plated bump to spherize with special passivation configuration.
3. Die orientated same as CAD picture for clarity (see: Removable die MCM - L/D/C).
4. Note contact resistance test pads on left edge.
5. Note traces for passivation crack detection.
6. Note temperature sensors in center of die.
7. Note traces for edge crack detection.
8. Note traces for die heating.
9. Note Particle Interconnect imprint.

BGA

Particle Interconnect - Sandia Lab Known Good Die (KGD)

Known-Good-Die probe/burn-in. Proof of removable die MCM-L/D/C.

• 0.030" pitch 19x19 miniBGA.
• Burn-in at 125 ° C, 168 hours.
• 0 failures, 100+ runs, no deformation.

0 failures, 11 runs shown above.	Particle Interconnect surface mount BGA socket.

Particle Interconnect - Sandia mBGA interposer schematic.	Sandia mBGA interposer