Rosin-free thermosetting flux formulations
OwnerMorgana de Avila Ribas, Rahul Raut +4inventors
InventorsMorgana de Avila Ribas, Rahul Raut, Traian Cornel Cucu, Shu Tai Yong, Siuli Sarkar, Ramakrishna Hosur Katagiriyappa
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Abstract
Rosin-free thermosetting flux formulations for enhancing the mechanical reliability of solder joints. In accordance with one or more aspects, a solder paste as shown and described herein imparts improved or enhanced solder joint properties relating to at least one of drop shock, thermal cycling, thermal shock, shear strength, flexural strength performance, and/or other thermal-mechanical performance attributes.
Claims28
A flux for an epoxy solder paste, the flux comprising:
- 20 to 40% by weight organic high-boiling solvents;
- 5 to 15% by weight multi-functional type epoxy resin;
- 15 to 30% by weight epoxy resin with high molecular weight;
- 15 to 30% by weight phenolic group containing hardening agent;
- 2 to 6% by weight anhydride based liquid hardener;
- 10 to 20% by weight carboxylic acid as an activator;
- 2 to 8% by weight substituted aromatic amine as catalyst;
- 1 to 5% by weight phosphene based salt as catalyst;
- 0.1 to 2% by weight amide based catalyst;
- 0.1 to 2% by weight bonding agent;
- and
- 0.1 to 4% by weight liquid type stress modifier.
An epoxy solder paste comprising an alloy and a flux, the flux comprising:
- 20 to 40% by weight organic high-boiling solvents;
- 5 to 15% by weight multi-functional type epoxy resin;
- 15 to 30% by weight epoxy resin with high molecular weight;
- 15 to 30% by weight phenolic group containing hardening agent;
- 2 to 6% by weight anhydride based liquid hardener;
- 10 to 20% by weight carboxylic acid as an activator;
- 2 to 8% by weight substituted aromatic amine as catalyst;
- 1 to 5% by weight phosphene based salt as catalyst;
- 0.1 to 2% by weight amide based catalyst;
- 0.1 to 2% by weight bonding agent;
- and
- 0.1 to 4% by weight liquid type stress modifier.
A solder joint formed with an epoxy solder paste, the epoxy solder paste comprising an alloy and a flux, the flux comprising:
- 20 to 40% by weight organic high-boiling solvents;
- 5 to 15% by weight multi-functional type epoxy resin;
- 15 to 30% by weight epoxy resin with high molecular weight;
- 15 to 30% by weight phenolic group containing hardening agent;
- 2 to 6% by weight anhydride based liquid hardener;
- 10 to 20% by weight carboxylic acid as an activator;
- 2 to 8% by weight substituted aromatic amine as catalyst;
- 1 to 5% by weight phosphene based salt as catalyst;
- 0.1 to 2% by weight amide based catalyst;
- 0.1 to 2% by weight bonding agent;
- and
- 0.1 to 4% by weight liquid type stress modifier.
A method of forming a solder joint with an epoxy solder paste, the epoxy solder paste comprising an alloy and a flux, the flux comprising:
- 20 to 40% by weight organic high-boiling solvents;
- 5 to 15% by weight multi-functional type epoxy resin;
- 15 to 30% by weight epoxy resin with high molecular weight;
- 15 to 30% by weight phenolic group containing hardening agent;
- 2 to 6% by weight anhydride based liquid hardener;
- 10 to 20% by weight carboxylic acid as an activator;
- 2 to 8% by weight substituted aromatic amine as catalyst;
- 1 to 5% by weight phosphene based salt as catalyst;
- 0.1 to 2% by weight amide based catalyst;
- 0.1 to 2% by weight bonding agent;
- and
- 0.1 to 4% by weight liquid type stress modifier;
- wherein the method comprises the step of applying the solder paste to a substrate.
An assembly comprising a printed circuit board, a shield can, and a solder joint formed between the printed circuit board and the shield can, wherein the solder joint is formed by an epoxy solder paste comprising an alloy and a flux, the flux comprising:
- 20 to 40% by weight organic high-boiling solvents;
- 5 to 15% by weight multi-functional type epoxy resin;
- 15 to 30% by weight epoxy resin with high molecular weight;
- 15 to 30% by weight phenolic group containing hardening agent;
- 2 to 6% by weight anhydride based liquid hardener;
- 10 to 20% by weight carboxylic acid as an activator;
- 2 to 8% by weight substituted aromatic amine as catalyst;
- 1 to 5% by weight phosphene based salt as catalyst;
- 0.1 to 2% by weight amide based catalyst;
- 0.1 to 2% by weight bonding agent;
- and
- 0.1 to 4% by weight liquid type stress modifier.
Dependencies are inferred from the claim text.