• Journal of the Semiconductor & Display Technology
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• v.20 no.1
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• pp.32-36
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• 2021

The number of processes in the manufacture of semiconductors, displays and solar cells is increasing. And as the processes is performed, multiple layers of films and various patterns are formed on the wafer. At this time, substrate warpage occurs due to the difference in stress between each film and pattern formed on the wafer. the substrate warping phenomenon occurs due to the difference in stress between each film and pattern formed on the wafer. We developed a new warpage measurement method to measure wafer warpage during real-time processing. We performed an experiment to measure the presence and degree of warpage of the substrate in real time during the process by adding only measurement equipment for applying additional electrical signals to the existing ESC and detecting the change of the additional electric signal. The additional electrical measurement signal applied at this time is very small compared to the direct current (DC) power applied to the electrostatic chuck whit a frequency that is not generally used in the process can be selectively used. It was confirmed that the measurement of substrate warpage can be easily separated from other power sources without affecting.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.6
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• pp.139-144
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• 2014

As a result of a mismatch of the residual stress between both sides of the silicon wafer, which warps and distorts during the patterning process. The accuracy of the warpage measurement is related to the calibration. A CCD camera was used for the calibration. Performing optimization of the error function constructed with phase values measured at each pixel on the CCD camera, the coordinates of each light source can be precisely determined. Measurement results after calibration was performed to determine the warpage of the silicon wafer demonstrate that the maximum discrepancy is $5.6{\mu}m$ with a standard deviation of $1.5{\mu}m$ in comparison with the test results obtained by using a Form TalySurf instrument.

• Journal of the Semiconductor & Display Technology
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• v.17 no.4
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• pp.86-90
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• 2018

Standards related to express the non-flatness of a wafer are reviewed and discussed, for example, bow, warp, and sori. Novel wafer warpage measurement method is proposed for 3D stacked IC application. The new way measures heat transfer from a heater to a wafer, which is a function of the contact area between these two surfaces and in turn, this contact area depends on the wafer warpage. Measurement options such as heating from room temperature and cooling from high temperature were experimentally examined. The heating method was found to be sensitive to environmental conditions. The cooling technique showed more robust and repeatable results and the further investigation for the optimal cooling condition is underway.

• Transactions of Materials Processing
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• v.15 no.1 s.82
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• pp.76-81
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• 2006

In this study, warpage characteristics of mobile phone cover through injection molding process were investigated using design of experiments in injection molding process. Warpage in plastic injection molding has a significant effect on quality of product. Effects of injection time, packing pressure, packing time, mold temperature and melt temperature on the warpage of mobile phone cover were considered by numerical analysis and experiment with Taguchi method. The degree of warpage for the injection molded part was measured by using three dimensional coordinate measurement machine. It was shown that temperature control factor has more significant effect on the warpage of mobile phone cover than pressure control factor.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.4
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• pp.83-87
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• 2022

Recently, as the thickness of the semiconductor package becomes thinner, warpage has become a major issue. Since the warpage is caused by differences in material properties between package components, it is essential to precisely evaluate the material properties of the EMC(Epoxy molding compound), one of the main components, to predict the warpage accurately. Especially, the cure shrinkage of the EMC is generated during the curing process, and among them, the effective cure shrinkage that occurs after the gelation point is a key factor in warpage. In this study, the gelation point of the EMC was defined from the dissipation factor measured using the dielectric sensor during the curing process similar with actual semiconductor package. In addition, DSC (Differential scanning calorimetry) test and rheometer test were conducted to analyze the dielectrometry measurement. As a result, the dielectrometry was verified to be an effective method for monitoring the curing status of the EMC. Simultaneously, the strain transition of the EMC during the curing process was measured using the FBG (Fiber Bragg grating) sensor. From these results, the effective cure shrinkage of the EMC during the curing process was measured.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.1
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• pp.47-52
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• 2008

We present a 3-D profiler specially devised for the profile measurement of rough surfaces that are difficult to be measured with conventional non-contact interferometer. The profiler comprises multiple two-point-diffraction sources made of single-mode optical fibers. Test measurement proves that the proposed profiler is well suited for the warpage inspection of microelectronics components with rough surface, such as unpolished backsides of silicon wafers and plastic molds of integrated-circuit chip package.

• Journal of the Semiconductor & Display Technology
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• v.15 no.4
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• pp.1-9
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• 2016

The warpage on mobile phone camera packages occurs due to the CTE(Coefficient of Thermal Expansion) mismatch between a thin silicon die and a substrate. The warpage in the optical instruments such as camera module has an effect on the field curvature, which is one of the factors degrading the optical performance and the product yield. In this paper, we studied the effect of die bonding epoxy on the package and optical performance of mobile phone camera packages. We calculated the warpages of camera module packages by using a finite element analysis, and their shapes were in good agreement showing parabolic curvature. We also measured the warpages and through-focus MTF of camera module specimens with experiments. The warpage was improved on an epoxy with low elastic modulus at both finite element analysis and experiment results, and the MTF performance increased accordingly. The results show that die bonding epoxy affects the warpage generated on the image sensor during the packaging process, and this warpage eventually affects the optical performance associated with the field curvature.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.3
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• pp.57-65
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• 2015

Electronic packages consist of various materials, and as temperature changes, warpage occurs because of the difference in coefficient of thermal expansion. Shadow $moir{\acute{e}}$ is non-contact, whole field measurement technique for out-of-plane displacement. However, the technique has low sensitivity above $50{\mu}m/fringe$, it is not adequate for the warpage measurement in some circumstance. In this paper, by applying phase shifting process to the traditional shadow $moir{\acute{e}}$, measurement system having enhanced sensitivity of $12.5{\mu}m/fringe$ is constructed. Considering Talbot effect, the measurement is carried out in the half Talbot area. Shadow fringe pattern having four times enhanced sensitivity is obtained by the image process with four shadow fringes. The measurement technique is applied to the fibered package substrate and coreless package substrate for measuring warpages at room temperature and at about $100^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.3
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• pp.241-246
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• 2012

A layered planer SOFC module was designed from planar-type SOFC. It was prepared by multi-layered ceramic technology. To form the cathode and the anode in the layered structure, reliable channels should be made on the both side of electrolyte perpendicularly. However, monolithic SOFC using multi-layered ceramic technology hasn't been studied another group, and the warpage of electrolyte in the channel, also, hasn't been studied, when electrode is printed on the electrolyte. In this study, the channels are prepared with electrode printing, and their warpage are evaluated. In the case of YSZ without electrode, the warpages are nothing in the limit of measurement using optical microscope. The warpage of 'YSZ-NiO printed' increases than that of 'NiO printed', and also, the case of 'double electrode printed' is similar to 'YSZ-NiO printed'. It is thought that, in the printed electrolyte, the warpage is related to the difference of the sintering behavior of each material.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.57-65
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• 2017

The electronic components in mobile device are composed of electronic chips and various other materials. These components become extremely thin and the constituent materials have different coefficient of thermal expansion, so that considerable warpages occurs easily due to temperature change or external load. Shadow $moir{\acute{e}}$ is non-contact, whole field technique for measuring out-of-plane displacement, but the measurement sensitivity is not less than $50{\mu}m/fringe$, which is not suitable for measuring the warpage of the electronic components. In this paper, we implemented a measurement method with enhanced sensitivity of $25{\mu}m/fringe$ by investigating and optimizing various experimental conditions of the shadow $moir{\acute{e}}$. In addition, four $moir{\acute{e}}$ fringe patterns recorded by the phase shift are processes to obtain a $moir{\acute{e}}$ fringe patterns with a sensitivity four times higher. The measurement technique is applied to small electronic components of a smart phone for measuring warpage with a high sensitivity of $5{\mu}m/fringe$ at room temperature and at the temperature of $100^{\circ}C$.