• 25g in a 30cc syringe
• Designed for the light-emitting diode (LED) industry
• Tolerates a wide range of reflow temperatures
• Suitable for use with high tin-containing and gold-tin solder alloys
• Low-voiding die-attach soldering to sub-mount 

LED TACFlux 007 is the leading die-attach flux for the light-emitting diode (LED) industry. It was specifically designed for die-to-sub-mount applications with sputtered film or solder preform alloys, with melting points that range from tin-silver (SnAg), SAC (SnAgCu) and pure tin (Sn) up to gold-tin (AuSn) eutectic, and is approved by leading LED manufacturers, such as Cree, for this purpose(1). It may be applied using various application techniques, holds the die in place during reflow, and is easily cleaned to give high wire bond pull strengths. The use of small quantities is recommended for best results.

Properties

LED TACFlux 007 is suitable for dispense, printing (both stencil and screen), and dipping/pin transfer. Using minimal quantities usually gives the best results, i.e., minimal voiding, little or no die float or skew, excellent solderability, and easy cleaning. The volume of flux on the die can be optimized by changing process parameters appropriate to the flux. A UV-fluorescent version of the flux, TACFlux 007-UV, is also available to help with process set-up and optimization.

Cleaning

LED TACFlux 007 may be removed using solvents, such as isopropyl alcohol, or standard semi-aqueous cleaning solvents. Indium Corporation’s Technical Support Engineers can recommend appropriate cleaning materials that are suitable for the application.

NOTE: LED die can be sensitive to the cleaning chemicals used to remove flux. The die supplier’s instructions on cleaning chemicals and cleaning procedures must be followed and should take precedence over the above guidelines.

Storage

For maximum shelf life, LED TACFlux 007 syringes and cartridges should be stored tip down. Storage temperatures should never exceed 30°C. After removing from cold storage, LED TACFlux 007 should be allowed to stand for at least four hours at room temperature before use.

Reflow

Reflow Atmosphere: A nitrogen (<100ppm oxygen) atmosphere is recommended.

Ramp Rate: A ramp rate of up to +5°C/second is recommended as a maximum.

Plateau: A plateau of 20-30 seconds at around 50°–60°C below the liquidus of the solder, while not essential, will help to remove volatile flux ingredients and reduce voiding in the final joint.

Peak Temperature: The peak temperature during reflow must not exceed the LED die manufacturer’s maximum allowed rating, and ideally, should be at least 20°C above the liquidus of the solder alloy. Standard alloys used in LED-attach are listed in the table below.

Cooling: A cooling rate of up to 10°C per second can typically be tolerated by LED die.