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Wafer backside coating

Wafer backside coating for wirebond laminate and leadframe packaging

AVAILABLE DIRECTLY AT CAPLINQ.COM

Wafer Backside Coatings

Wafer backside coating materials allow for screen or stencil printing of the paste across the entire wafer in a single stroke, increasing throughput by eliminating the need to individually dispense dots of adhesive.

Wafer backside coating provides consistent bond lines and small, controlled fillets which are particularly effective for attaching small die in miniaturized packages and challenging structures like chip on lead where the die pad is smaller than the die. It enables process speed, thickness control and material uniformity and it is critical for die attach applications where fillet control is critical.

Product Selector Guide

Electrically Conductive Wafer Backside Coating (WBC) Adhesives
Product Description Key attributes
 Die size (mm) Substrate finish Moisture sensitivity level, MSL Volume resistivity (Ohm-cm) Thermal conductivity (W/m-k) Recommended cure
Loctite Ablestik 8008
 Ag-filled, die attach wafer backside coating adhesive - Excellent stencil printing and low surfaces roughness
- Viod-free bondline without bleed
- Oven B-stage and snap or oven cure 		<3X3 Cu, Ag or PPF L1 260°C capable 1.0X10-4 2.2 60 sec. at 230°C (snap)
Loctite Ablestik 8008HT Ag-filled, die attach wafer backside coating adhesive
 - Applied by stencil printing
- Viod-free bondline without bleed
- Oven B-stage and snap or oven cure		 <1X1 Cu, Ag or PPF L1 260°C capable 6.0X10-5 11.0 20 sec. at 170°C (snap)
Loctite Ablestik 8008MD Ag-filled, die attach wafer backside coating adhesive
 - Applied by stencil printing
- Low stress
- Good substrate wetting
- Oven B-stage and snap or oven cure		 <4X4 Cu, Ag or PPF L1 260°C capable 5.0X10-4 6.0 10 min. ramp and 60 min. hold at 115°C
Electrically Non-Conductive Wafer Backside Coating (WBC) Adhesives
Product Description Key attributes
 Die size (mm) Substrate finish Moisture sensitivity level, MSL Modulus at 25°C (MPa) CTE (ppm/°C)
Below Tg
Above T g		 Recommended cure
Loctite Ablestik 8006NS Alumina/silica-filled, epoxy die attach wafer backside coating adhesive - Applied by stencil or screen printing
- Consistent bondline down to 25 um
- Oven B-stage and oven cure 		<4X4 Cu, Ag or PPF L1 260°C capable 4,376 33
136		 2 hr. at 160°C
Loctite Ablestik WBC 8901UV Die attach wafer backside coating adhesive
 - Wide process windows
- 5 to 60 um bondline control
- Low viscosity before B-stage
- Can be spray coated on dicing before grinding (DBG) wafers
- UV B-stage oven cure		 <1X1 Cu, Ag or PPF L2 260°C capable 3,585 45
142		 15 min. ramp and 30 min. hold at 90°C +4 min. ramp and 45 min. hold at 120°C

Learn More

Wafer backside coatings

Wafer Backside Coating is a unique process that facilitates automated application of die attach adhesive at the wafer-level followed by B-staging to form a die attach film. Adaptable to spray coating technique, Henkel’s Wafer Backside Coatings enable process speed, thickness control and material uniformity. Following thermal or UV B-staging and wafer dicing, die attach is achieved via heat and pressure to produce a consistent bond line and small, controlled fillets. Wafer Backside Coating adhesives are ideal for die attach applications where fillet control is critical.

These materials can be Silver, Silica or Alumina filled to determine their conductive and non conductive nature. They excel in stencil printing and they can achieve a void free bondline without bleed. Oven and UV B-stage as well as Oven cure are all viable curing options, depending on the product line.

Wafer Backside Coating materials allow for screen or stencil printing of the paste across the entire wafer in a single stroke, increasing throughput by eliminating the need to individually dispense dots of adhesive. After B-staging to create a film, Wafer Backside Coating provides consistent bond lines and small, controlled fillets, which are particularly effective for attaching small die in miniaturized packages and challenging structures like chip-on-lead, where the die pad is smaller than the die.

The coating can be applied on Copper, Silver or PPF (Palladium pre plated leadframes) and the result can be MSL L1 capable with thermal conductivity varying from 2.2 up to 11 (W/m·K)