Today’s higher density microelectronic packaging is required to satisfy the functionality of the newest generation of integrated circuits. This new generation of packages includes BGA’s, flip chip and copper pillar technologies, 2.5/3D packages, and fine pitch chip scale components. In addition, the introduction of new polymeric flux chemistries used in lead free solder pastes for solder reflow has required changes in how assemblies are processed. The many challenges of assembling printed circuit boards require new process technologies, equipment, and materials.
The primary interconnect method of components to the printed circuit board is soldering and is dependent on the degree of wetting between solder and the materials to be joined. When printed circuit boards are soldered in air, the metal alloy systems used in electronic assembly processes are subject to oxidation. Tin oxides form rapidly in an air environment and these oxides inhibit wetting of the molten alloy to printed circuit board lands and component leads which can result in soldering defects. The use of nitrogen as a process gas provides an inert, reduced oxygen soldering atmosphere. By eliminating the formation of solder oxides, wetting is promoted and soldering quality is improved.
Benefits of Inert Atmospheres:
- Elimination of metal surface oxidation
- Improves wetting of solder to component leads and board
- Reduces common defects such as bridging, non-wetting; insufficient solder and cold solder joints.
- Improves alignment of components
- Compatible with low residue flux solder pastes
- Improves flux activity by reducing the polymerization of the flux and reduced new metal oxide formation
- Improves First pass soldering yields
- Reduces rework labor, improves productivity
- Provides a wider process window
How can Air Products help you achieve improved soldering results?
- Process Audits of your assembly lines
- Trial programs
- Optimization programs
- In house technology seminars
Expertise, technology, and gases: A total solution for the global electronics packaging, assembly and test industry
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Benefits of inert gas soldering for printed circuit board assembly processes
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Facilitating the reduction of head-in-pillow defects and improving assembly reliability and in-line productivity using nitrogen reflow
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Cost effective and user friendly nitrogen inerting technology for lead-free wave soldering
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