Thermomechanical behaviour of PBGA package during laser and hot air reflow soldering

Tian, Yanhong; Wang, Chunqing; Liu, Deming

doi:10.1088/0965-0393/12/2/005

Cited by 19 publications

(10 citation statements)

References 8 publications

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“…Interfacial reactions between solder balls and Au/Ni/Cu metallisation in PBGA packages by traditional reflow methods have been extensively studied (Ferguson et al , 1997; Ho et al , 2000; Kim and Tu, 1998; Song et al , 2001; Zribi et al , 2000). However, the reaction kinetics between Au/Ni/Cu pads and solder bumps during laser reflow have not been widely reported (Tian et al , 2002a, b).…”

Section: Introductionmentioning

confidence: 99%

Interaction kinetics between PBGA solder balls and Au/Ni/Cu metallisation during laser reflow bumping

Tian

Wang

Zhang

et al. 2003

Soldering &Amp; Surface Mount Technology

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In this paper, the interaction kinetics between eutectic PbSn solder and Au/Ni/Cu metallisation of plastic ball grid array packages during laser reflow bumping were investigated. The effects of processing variables, including laser reflow power and time, on the morphology of the intermetallic compounds formed at the solder/pad interface were studied by scanning electron microscopy and energy dispersive X‐ray spectrometry. Furthermore, dissolution and diffusion of Au and Sn inside the solder bump within the duration of the laser heating was analysed by Auger electron spectroscopy (AES). The results reveal that the morphology of the intermetallic compounds was strongly influenced by the laser input energy. The AES results showed that Au atoms dissolved rapidly into the solder after the solder was melted.

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Section: Introductionmentioning

confidence: 99%

Interaction kinetics between PBGA solder balls and Au/Ni/Cu metallisation during laser reflow bumping

Tian

Wang

Zhang

et al. 2003

Soldering &Amp; Surface Mount Technology

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“…Consequently, more Au will be dissolved and extend further into the solder alloy. As a result, long needle‐like AuSn 4 IMCs are easily formed, the AuSn 4 IMCs are prone to be perpendicular with the pad, due to the direction of the enhanced temperature gradient also being nearly perpendicular to the pad (Tian et al , 2004). Furthermore, more Au‐rich phases will be consumed than those in LR solder joints protected by N 2 atmosphere at room temperature and 60°C.…”

Section: Resultsmentioning

confidence: 99%

Oxidation and Au‐Sn reaction of laser reflowed micro‐solder joints protected by N2 or exposed to air atmosphere

Liu

Tian

Yang

et al. 2012

Soldering &Amp; Surface Mount Technology

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PurposeThe purpose of this paper is to investigate oxidation and the Au‐Sn reaction of laser reflowed (LR) micro‐solder joints when different protective atmospheres were applied.Design/methodology/approachA N2 atmosphere at room temperature, 60°C, 100°C and 130°C, or an air atmosphere at room temperature were utilized in this study. The solder balls were composed of Sn‐2.0Ag‐0.75Cu‐3.0Bi, and 120 μm in diameter. The surface finish of one pad of the joints was 4.0 μm Au/0.1 μm NiFe/0.01 μm Ta, another pad was made of Cu plated with 3.0 μm Au. The laser reflow process time was controlled to within 10 ms. Auger Electron Spectroscopy (AES) was used to identify the oxidation condition of LR solder joints with or without protection from a N2 atmosphere at room temperature. The appearance and cross‐sections of the joints protected by a N2 atmosphere at different temperatures were evaluated using SEM analysis.FindingsOxidation of LR solder joints from an air atmosphere was extremely severe, and the surfaces of solder were rough as compared with joints protected by a N2 atmosphere. Au‐rich phases and needle‐like AuSn4 intermetallic compounds (IMCs) formed at the interfaces of the solder and the pads. As the temperature of the N2 atmosphere was increased above 100°C, almost all of the Au‐rich phases disappeared. More needle‐like AuSn4 IMCs formed at the interfaces, as compared with that in joints protected by a N2 atmosphere at room temperature and 60°C. In addition, the orientation of the IMCs had clearly changed.Originality/valueThe results may provide a guide for controlling oxidation and the Au‐Sn reaction of micro‐solder joints during the LR process, and improving the properties of joints between solder and pads with Au surface finishes, by regulating the protective atmosphere.

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“…Heat transfer occurs from a region of high temperature to a region of low temperature, as described by the second law of thermodynamics. From the Fourier law of heat transfer, during an infinitely small time , heat energy is produced when the medium passes through an infinitely small area, , along the normal, and is proportional to the medium temperature directional derivative, / , which points along the normal to the surface [14]:…”

Section: Energy Conservation Model Of the Laser Soldering Systemmentioning

confidence: 99%

A Novel Thermodynamic Model and Temperature Control Method of Laser Soldering Systems

Chen

Zheng

et al. 2015

Mathematical Problems in Engineering

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Laser technology is vital in production of precision electronic components and has been widely used in modern industry. In laser soldering systems, accurate temperature control remains a challenging problem, since the temperature is highly sensitive to laser power and thermodynamic parameters of solder joints. In this paper, a good solution is proposed to solve the problem by controlling the temperature based on a novel thermodynamic model. In the model, many of the major factors are taken into account, such as laser energy, flux influence, and solder joints with different parameters. Aimed at the thermodynamic process and the influence of solder fluxes, a mixed mode control method is used to track the designed target temperature curve; this method can produce a solder joint with good quality. As a result, a model-based feed-forward and proportional, integral, and derivative (PID) mixed control method is developed. In practice, the proposed method is verified to have a wider product capability and production size; and a rate of good products of 99.94% is achieved with consuming approximately half of the energy comparing with manual soldering and constant laser power soldering.

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Thermomechanical behaviour of PBGA package during laser and hot air reflow soldering

Cited by 19 publications

References 8 publications

Interaction kinetics between PBGA solder balls and Au/Ni/Cu metallisation during laser reflow bumping

Interaction kinetics between PBGA solder balls and Au/Ni/Cu metallisation during laser reflow bumping

Oxidation and Au‐Sn reaction of laser reflowed micro‐solder joints protected by N2 or exposed to air atmosphere

A Novel Thermodynamic Model and Temperature Control Method of Laser Soldering Systems

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