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

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

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125 °C

1 hr.

1 hr.

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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.

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