Lead-Free Solder Paste

I work for DuPont and we supply engineering thermoplastics to the connector industry. We heard that there's a trend towards lead-free solder paste. Can anybody tell me name of companies that are already using lead-free solder paste in US and Europe? Is this is real trend? What consequences lead-free solder pasted will have on SMT processing temperature? Thanks in adavance for your support. Regards, Barbara

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Here at M/A-Com we use lead free solder pastes for two purposes, environment and prevention of secondary reflow in subsequent processes. The UK engineering journals all report the trends towards lead free alloys, especially in the telecommunications industry. Companies such as Nortel, Ericsson and Nokia are all evaluating these materials. The main issues I find with the processing temperatures is the effect on the PCBs. The peak temperature of 250 degress C is on the limits or even above the maximum temperature for FR4. So the important issues is to reflow and cool in as little time as possible. We are using 0402 packages which leads to problems with tombstoning. Regards. Steve Brown. Process Engineer

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Barbara, I worked for 5 years with advanced materials including silver filled thermoplastics and epoxies for Alphametals. There is a trend towards lead free "solder paste". Some companies are using an Indium alloy paste and others are using a "leadfree" Silver paste. As for silverfilled or other conductive filled materials it would be necessary that they work in the same amount of time that solder paste does and without pressure applied to the components during the bonding cycle to see widespread acceptance in the industry. Ease of rework is an issue also as solder is fairly user friendly when it comes to reworking a board. If you want further info, don't hesitate to email me and I will give you phone number so we can chat. | I work for DuPont and we supply engineering thermoplastics to the connector industry. | We heard that there's a trend towards lead-free solder paste. | Can anybody tell me name of companies that are already using lead-free solder paste in US and Europe? | Is this is real trend? | What consequences lead-free solder pasted will have on SMT processing temperature? | Thanks in adavance for your support. | Regards, Barbara |

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