Solder Alloys

Durafuse LT – Low-Temperature Alloy System

The tough choice that is easy to make.

Durafuse LT

Durafuse LT is a patented low-temperature alloy system designed to provide high-reliability in low-temperature applications that require a reflow temperature below 210°C.

Durafuse LT provides improved drop shock resilience, outclassing bismuth-tin (BiSn) or bismuth-tin-silver (BiSnAg) alloys, and performing better than SAC305 with optimum process setup. Durafuse LT is made up of a low-melting indium-containing alloy and a higher-melting SAC alloy. The SnInAg alloy initiates joint fusion while the SAC alloy provides enhanced strength and durability. Durafuse LT is ideal for high-reliability applications, which utilize thermally sensitive components or boards and/or have a requirement for step soldering.

Durafuse LT Features & Benefits

  • Drop Shock – Performance is more than two orders of magnitude better than Bi-containing low-temperature materials
  • Drop Shock - Performance is equal or better than SAC305 with proper process optimization
  • Ideal for step soldering and low temperature requirements

Durafuse LT

Obtains the benefits of low-temperature processing reduced warpage and other negative effects on substrates and components without sacrificing reliability.
Dropping electronics is a fact of life. Durafuse<sup>™</sup> LT allows for end-product durability.

Low-Temperature Solder

Durafuse LT and the Low- to Mid-Temperature Solder Space
Low-Temperature Solder Innovation Webinar screenshot

Improving Drop Shock Resistance

Drop Shock (44g ball at 500mm drop height) Fusion Time vs. Drop Shock Performance: Depending on peak temperature, time at peak can be used to optimize for drop-shock resilience.

Low Temp Alloy Technology

Durafuse LT contains a low-melting indium-based alloy which initiates joint fusion, while the high-melting SAC alloy provides enhanced strength and durability

Solder Joint Fusion

Step Soldering

  • Meeting requirements for step soldering, particularly in RF shield attachment and rework applications
    • Peak reflow temperature between 200°C and 210°C
    • Shear strength retained above 150°C

Durafuse LT Recommended Reflow

Optimization of the reflow profile with a plateau at peak temperature is essential for maximizing drop shock reliability

  • A 200°C peak reflow temperature requires a longer plateau region
  • Increasing peak temperature to 205 or 210°C allows for reduced reflow time
  • This profile is a general guideline in establishing a reflow profile for Durafuse LT in Indium5.7LT-1

Related Applications

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