SHANGHAI - Lenovo today announced a new patent-pending low temperature solder process developed to improve PC manufacturing by conserving energy and increasing reliability.

The computer maker developed the solder to counter stresses caused by use of high tin solders which require extremely high temperatures, consuming energy and adding significant stress on components. Lenovo studied thousands of combinations of solder paste material composed of a mixture of tin, copper, bismuth, nickel and silver, fluxes and time and heat temperature profiles as part of its research.

According to Lenovo, the LTS is a non-eutectic SnBi alloy with a melting point between 134C-144C. The paste was developed in concert with Alpha and Senju. A novel flux was developed for the alloy.

Testing was performed on a specially designed coupon with BGA packages such as Intel CPU, CSP and others. All components were mounted on a ThinkPad for testing purposes. The largest and smallest package sizes successfully processed were a CPU (Intel Skylake and Kabylake) and 01005 passive. The new LTS can be universally applied to all electronics manufacturing involving printed circuit boards with no cost or performance impact to customers, Lenovo said.

After validation of the procedure, Lenovo discovered a significant reduction in carbon emissions as a result of using the new process. The procedure is already in production for ThinkPad E series and the 5th generation X1 Carbon recently announced at CES. Throughout 2017, Lenovo intends to implement the new LTS process on eight SMT lines and estimates savings of up to 35% on carbon emissions. By the end of 2018, Lenovo aims to have 33 SMT lines with two ovens per line using this new process, giving an estimated annual saving of 5,956 metric tons of CO₂. To put this into perspective, the equivalent reduction in CO₂ emissions is equal to the consumption of 670,170 gallons of gasoline per year.

Lenovo also expects better reliability for its devices due to lower heat stress during reflow soldering/ In the early stages of deployment, Lenovo has observed a 50% decrease in printed circuit board warpage and a reduction in defective parts per million during the manufacturing process.

“By implementing the new LTS process, Lenovo is continuing to show its commitment to upholding sustainable business practices across its PC business,” said Luis Hernandez, vice president, Lenovo PC and Smart Devices Integrated Development Center. “Our focus on innovation extends beyond R&D and product design, to the way our products are manufactured. We are dedicated to advancing our business goals while reducing our impact on the environment and we’re proud this process achieves that.”

Ed.: Updated Feb. 10

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