In-situ measurements of surface mount IC package deformations during reflow soldering

Pecht, Michael; Govind, Annu

doi:10.1109/3476.649442

Cited by 36 publications

(19 citation statements)

References 12 publications

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“…In this work, the chip was substituted by a magnet, the orientation of which was detected using Hall sensors. Another sensor for real-time monitoring was applied during assembly on printed-circuit boards [21]. It measured the microelectronic package deformation during infrared reflow soldering using cantilever beam probes touching the package surface.…”

Section: Microelectronic Package Evaluationmentioning

confidence: 99%

Microelectronic Bonding Processes Monitored by Integrated Sensors

Mayer¹,

Schwizer

2002

Sensors Update

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Real-time monitoring methods are beneficial for the control, optimization, and failure analysis of microelectronic packaging processes. The focus of this chapter is on the real-time monitoring of two widely used processes, soft solder die bonding and thermosonic ball bonding. The methods presented here use uniquely developed microsensors integrated on custom-made test chips using commercial double-metal CMOS processes.For the soft solder die bonding process, nine aluminum-based resistive temperature detectors were integrated on various locations on a test chip. The temperature was monitored during the placement of the test chip on the leadframe. The experimental results describe the wetting and spreading effects of the molten solder under the drip. Together with numerical results obtained with a transient thermal finite element model, the beginning of wetting can be quantified. For the soft solder PbSn10, wetting occurred around 30 ms after touch down. This method hence can be used to determine wetting times under different process conditions. The wetting time determines an upper limit of the throughput of the process.For the thermosonic ball bonding process, temperature and force sensors were integrated on test chips. The sensors are aluminum resistors and piezoresistive p + -and n + -diffused resistors placed around bond pads. A bond quality parameter can be derived from the temperature signal variation during bonding. The piezoresistive sensors permit the measurement of forces in the x-, y-, and z-directions simultaneously. The ultrasonic tangential force signal reached a typical value of 0.12 N on a 50 lm diameter contact zone and revealed significant process characteristics. Four process phases are identified which are necessary for a successful ball bond formation. These phases are assigned to initial stiction, sliding, bond growth, and deformation effects.

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Section: Microelectronic Package Evaluationmentioning

confidence: 99%

Microelectronic Bonding Processes Monitored by Integrated Sensors

Mayer¹,

Schwizer

2002

Sensors Update

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“…Therefore, the PCB and DIMM sockets would deform and warp simultaneously resulting from the CTE mismatch under a thermal load, as illustrated in Figure 2b. In 1997, a real-time strain-gauge probe method for measuring and recording the in-process deformation of packages during a simulated solder reflow process was developed [3]. Strain gauges have been widely used in measuring the mechanical strain on a PCB due to their reliable and easyto-use characteristics.…”

Section: Methodologiesmentioning

confidence: 99%

Measurements of Thermally-Induced Curvatures and Warpages of Printed Circuit Board during a Solder Reflow Process Using Strain Gauges

et al. 2017

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Abstract:Measurements of the curvatures and warpages of a printed circuit board (PCB) during a thermal solder reflow process using strain gauges are proposed in this study. In the experiments, a shadow moiré is used for measuring the out-of-plane deformations (or warpage) of a bi-material plate and a PCB with dual in-line memory module (DIMM) sockets during solder reflow heating, while the finite element method (FEM) is used to analyze the thermally-induced deformation of the PCB specimen for ensuring the validity of the measurement. Conventional strain gauges are employed to measure the strains (albeit as in-plane strain data) in both specimens during the solder reflow process. The results indicate that the strain gauge-measured strain data from the top and bottom surfaces of both specimens during the solder reflow can be converted into curvature data with specific equations, and even into global out-of-plane deformations or warpages with a proposed simple beam model. Such results are also consistent with those from the shadow moiré and FEM. Therefore, it has been proved that the strain gauge measurement associated with the simple beam model can provide a method for the real-time monitoring of PCB deformations or warpages with different temperatures during the solder reflow process.

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“…Vice versa, it is believed that in bake process, moisture localized in this area will be difficult to be desorbed, which is a really critical part in manufacture. Some other important factors, such as vapor pressure [20], thermal stress [21] and hygroscopic stress [22] should be taken into consideration for the future work. This FEA results indicate the substrate determine hygroscopic performance of the units, which aligned well those finding in the above experiment.…”

Section: Resident Moisturementioning

confidence: 99%

Study on moisture behavior in flip chip BGA packages and bake process optimization

Dai

Hua

Dai

et al. 2009

2009 International Conference on Electronic Packaging Technology &Amp; High Density Packaging

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The Lead-Free (LF) and Halogen-Free (HF) "green" initiatives are driving the advanced packaging manufacturers to develop new generation materials and assembly technologies. However, the moisture related reliability issues become the significant technical challenge to meet stringent reliability and quality standards comparing to the previous Lead and Halogen technology. In this study, the moisture absorption and desorption performance of Halogen Free and Lead Free material were investigated. The experimental data revealed that after fully baked process there was still some resident moisture which was mainly contained at substrate level. The modeling data of moisture absorption and desorption behavior with 125°C bake comparison was discussed and was fully aligned with experimental data. Moreover, a 'soft bake' method via Nitrogen and dry air was introduced. In low RH effect test, under 25°C / 60%RH precondition process, all the moisture absorbed for 1100 hours can be removed by 'soft' bake. This indicates that not only no moisture absorption in low RH environment, but also an additional 'soft bake' process occurring during the storage time. The results demonstrated that the storage of moisturesensitive material in the optimized environment is an attractive facility solution which can reduce the risk of popcorn and cracking problems.

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In-situ measurements of surface mount IC package deformations during reflow soldering

Cited by 36 publications

References 12 publications

Microelectronic Bonding Processes Monitored by Integrated Sensors

Microelectronic Bonding Processes Monitored by Integrated Sensors

Measurements of Thermally-Induced Curvatures and Warpages of Printed Circuit Board during a Solder Reflow Process Using Strain Gauges

Study on moisture behavior in flip chip BGA packages and bake process optimization

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