Microcircuit Silvers

for Conductive Bonding in Microelectronics

One-part thermosetting silver epoxy systems for conductive bonding in microelectronic assembly operations.

MICROCIRCUIT SILVER – TYPE K
Low temperature, fast cure- automatic dispensing

MICROCIRCUIT SILVER – TYPE L
Low temperature, fast cure – screen print

MICROCIRCUIT SILVER – TYPE N
High bond strength – 100% solids

MICROCIRCUIT SILVER – TYPE O
High electrical conductivity – 100% solids

MICROCIRCUIT SILVERS

Microcircuit Silvers are one-part, thermosetting silver-epoxy compositions designed specifically for conductive bonding in microelectronic assembly operations. Recommended applications include the conductive bonding of integrated circuit chips, capacitors, and other active and passive components. Microcircuit Silvers meet Hi-Rel requirements for low outgassing, bond strength, and electrical conductivity.

Microcircuit Silvers withstand temperatures up to 350 °C, allowing ultrasonic and thermal compression bonding of interconnecting wires. Microcircuit Silvers Types K and L, will fully cure in 15 seconds at 300 °C; thus these silver compositions possess the unique ability to cure during thermal compression bonding operations.

Several modifications of Microcircuit Silvers are offered. Types K and L exhibit low temperatures and fast cures. Types N and O are 100% solid systems which provide high electrical conductivity. Microcircuit Silvers Type K,L,N, and O are designed for screen printing or automatic dispensing applications.

Properties of Microcircuit Silvers

Type K Type L Type N Type O
Uncured
Per Cent Silver 75 73 70 77
Solids (%) 98 98 100 100
Viscosity cps 60,000 80,000 100,000 125,000
Shelf Life-70 °F > 6 months > 6 months 6 months 6 months
Application Automatic dispense Screen print/dispense Screen print/dispense Screen print
Cured
Serv. Temp Range -50 °C to + 175 °C (325 °C intermittent) same -60 °C to + 200 °C (325 °C intermittent) same
Electrical Resistivity
ohm-cm
5 x 10-4 5 x 10-4 2 x 10-3 6 x 10-4
Linear Coef. Therm Exp. (cm/cm°C) 5 x 10-5 same same same
Thermal Conductivity (BTU hr/ft2/°F/in.) 21 20 20 22
Outgassing
1000 hrs @ 100 °C 0.05% .05% .09% .08%
1000 hrs @ 125 °C 0.2% .2% .7% .6%
Bond Shear Strength(psi) after cure 1500 >1500 3500 1500
aged 200 hrs @ 175 °C >1000 >1000 2750 1000
Cure Schedule (Select Temp.)
115 °C 1 1/2 hrs 1 1/2 hrs —- —-
125 °C 1 hr. 1 hr. —- —-
135 °C 30 min 30 min 5 hrs 5 hrs.
150 °C 15 min 15 min 1 1/2 hrs. 1 1/2 hrs.
175 °C 5 min 5 min 30 min 30 min
300 °C 15 sec. 15 sec. —- —-