Die Bonding Services

Die Bonding Services

Die bonding is the process of attaching a die to substrate/package. Selection of the optimal die attach material and process is based on a number of issues including thermal requirements, electrical requirements and mechanical stability.

Solder Die Attach

Optocap has experience with a wide range of solder materials including soft and hard solders, Pb-free solders, Eutectic solders and solders for operation over a wide temperature range.

This knowledge is critical in supporting our customers in making the correct decisions on solder material selection for their product.

For many Opto, MEMS or Sensor devices fluxes can pose reliability concerns with contamination of the sensitive active regions of these devices. As a result many of the solder attach processes at Optocap are based on a flux free solder process utilizing solder preforms or pre-tinned substrates with a subsequent Vacuum Reflow processes, or reflow using Pulsed Heat-Stages with reducing or cover gas to prevent oxidation.

In order to use a solder attach process the components require a compatible metal surface. Optocap can provide input on appropriate surface finishes.

Solder pastes are screen printed onto substrates in patterns defined by custom designed stencils. Components are then pick and placed into the solder paste and reflowed using conventional IR reflow processes.

Optocap has experience with a wide range of solder materials including soft and hard solders, Pb-free solders, Eutectic solders and solders for operation over a wide temperature range.

For many applications, including laser diode or HB-LED die attach, a good void-free interface is required. Control of process parameters, such as the downward force and reflow profiles, is crucial in achieving a void-free joint. Where appropriate Optocap uses its Micro-Focus x-ray capability to asses the voiding level in the solder joint and die shear capability to asses the mechanical strength of the joint. All die attach processes are inspected and tested to MIL-STD, or greater if required by the customer.

Optocap’s expertise and capability in die bonding will reduce risk and reduce time to market for your die bonding requirements as well as providing a cost-effective manufacturing option.

Epoxy Die Attach

Optocap has extensive knowledge on the rheology, thermal, electrical and cure properties of a wide range of epoxy materials.

This knowledge is critical in supporting our customers in making the correct decisions on epoxy selection for their product.

The manufacture of many microelectronic and optoelectronic devices requires the precise control of the epoxy process. Bond lines must be of specific shape and thickness to ensure good thermal properties. Epoxy squeeze out must be controlled to prevent shorting or bridging. Full epoxy coverage with no voiding is important for thermal performance and to minimize stresses. Optocap utilizes automated fluid dispensers and automated die bonders to develop a high yield and automated process whilst meeting the stringent assembly requirements outlined above.

When small components need to be attached or when many components need to be attached in close proximity to each other then very small dots of epoxy need to be used to avoid shorting. Optocap utilizes epoxy stamping or daubing techniques, whereby a pin transfers a precisely controlled amount of epoxy from an epoxy reservoir onto a package or substrate to provide epoxy spot sizes on the order of 100 microns.

For dispensing lines of epoxy or lines for an area fill then epoxy from a syringe is dispensed using a pump. Time/Pressure or Positive Displacement pumps can be used to provide a consistent epoxy volume and pattern.

The option also exists to Screen Print epoxy but this is infrequently used in Microelectronics Assembly. Optocap also has experience in the epoxy attach processes using epoxy films.

Optocap works closely with our customers to select the optimal materials and process for their application. Optocap’s expertise and capability in die bonding will reduce risk and reduce time to market for your die bonding requirements as well as providing a cost-effective manufacturing option.

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