In-situ thickness measurement of epoxy molding compound in semiconductor package products using a Terahertz-Time of Flight System

Park, Dong Woon; Oh, Gyung Hwan; Kim, Dug Joong; Kim, Kwang Ho

doi:10.1016/j.ndteint.2019.04.012

Cited by 20 publications

(5 citation statements)

References 19 publications

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“…The presence of epoxy molding compounds (EMCs) in the package generally might affect the performance of encapsulated detectors, and this influence needs to be evaluated. Multiple studies of various EMCs in the THz range [ 29 , 30 , 31 ] indicated their very similar refractive index values of

, n = 1.897–1.940, and

, respectively. The obtained small variations of the refractive index were attributed to differences in the silica filler content [ 30 ].…”

Section: Methodsmentioning

confidence: 99%

“…Multiple studies of various EMCs in the THz range [ 29 , 30 , 31 ] indicated their very similar refractive index values of

, n = 1.897–1.940, and

, respectively. The obtained small variations of the refractive index were attributed to differences in the silica filler content [ 30 ]. Such refractive index values can possibly lead to front surface reflectance of the order of 11%, but can also contribute to a more gradual refractive index transition between the free space and the HEMT substrate.…”

Section: Methodsmentioning

confidence: 99%

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Design and Performance of Extraordinary Low-Cost Compact Terahertz Imaging System Based on Electronic Components and Paraffin Wax Optics

Tamošiūnas

Minkevičius

Bučius

et al. 2022

Sensors

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Terahertz (THz) imaging is a powerful technique allowing us to explore non-conducting materials or their arrangements such as envelopes, packaging substances, and clothing materials in a nondestructive way. The direct implementation of THz imaging systems relies, on the one hand, on their convenience of use and compactness, minimized optical alignment, and low power consumption; on the other hand, an important issue remains the system cost and its figure of merit with respect to the image quality and recording parameters. In this paper, we report on the design and performance of an extraordinary low-cost THz imaging system relying on a InP Gunn diode emitter, paraffin wax optics, and commercially available GaAs high-electron-mobility transistors (HEMTs) with a gate length of 200 nm as the sensing elements in a room temperature environment. The design and imaging performance of the system at 94 GHz is presented, and the spatial resolution in the range of the illumination wavelength (∼3 mm) and contrast of nearly two orders of magnitude is determined. The operation of two models of the HEMTs of the same nominal 20 GHz cut-off frequency, but placed in different packages and printed circuit board layouts was evaluated at 94 GHz and 0.307 THz. The presence of two competing contributions—self-resistive mixing and radiation coupling through the antenna effects of the printed circuit boards—to the detected signal is revealed by the signal dependence on the gate-to-source voltage, resulting in a cross-sectional responsivity of 27 V/W and noise-equivalent power of 510 pW/Hz at 94 GHz. Further routes in the development of low-cost THz imaging systems in the range of EUR 100 are considered.

show abstract

, n = 1.897–1.940, and

, respectively. The obtained small variations of the refractive index were attributed to differences in the silica filler content [ 30 ].…”

Section: Methodsmentioning

confidence: 99%

“…Multiple studies of various EMCs in the THz range [ 29 , 30 , 31 ] indicated their very similar refractive index values of

, n = 1.897–1.940, and

Section: Methodsmentioning

confidence: 99%

Design and Performance of Extraordinary Low-Cost Compact Terahertz Imaging System Based on Electronic Components and Paraffin Wax Optics

Tamošiūnas

Minkevičius

Bučius

et al. 2022

Sensors

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show abstract

“…By utilizing the normal reflection and transmission modes of THz-TDS, it is possible to simultaneously measure the refractive index and thickness of EMC materials. 29 This simultaneous measurement presents a significant advancement in material characterization techniques. However, this method faces limitations when applied to non-transparent samples, such as HI packaging that consists of multiple layers.…”

Section: Materials and Structure Measurementmentioning

confidence: 99%

THz-TDS for IC packaging material changes detection under real-world conditions

Xi,

Varshney,

Khan

et al. 2024

Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications XVII

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Hardware security has been a significant challenge in semiconductor devices, leading to serious issues such as denial of service, data leakage etc at both transistor as well as package level. Detecting the usage state of a target semiconductor sample or generating a unique fingerprint can provide critical information about the sample, aiding in the prevention of counterfeiting to avoid hardware security risks. Terahertz Time-Domain Spectroscopy (THz-TDS) stands out as a powerful and non-destructive tool, capable of probing and analyzing the polymer materials. Its sensitivity to molecular-level changes makes THz-TDS suitable for studying the material, structural, and stress properties of IC packaging under real-world conditions. This research begins by reviewing the composition of Electronic Material Compatibility (EMC) materials and their variance under real-world conditions. Furthermore, the application of THz-TDS for polymer material characterization, which incloudes material, structural, and internal stress characterization, is also thoroughly reviewed. By combining these factors, we explore the potential and capability of using THz-TDS to detect real-world loaded samples and the feasibility of generating fingerprints for identifying counterfeit samples, including reused, recycled, or tampered ones.

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“…In non-contact measurement, there are active and passive measurement methods. The terahertz-time of flight system, digital holographic interferometry and structured light, which are typical active methods, have fast measurement speeds and high precision [ 11 , 12 , 13 ]. However, active methods require extra devices to generate specific signals, increasing the complexity and cost of the equipment.…”

Section: Introductionmentioning

confidence: 99%

An Improved Shape from Focus Method for Measurement of Three-Dimensional Features of Fuel Nozzles

Hou

Zou

Zhang

et al. 2022

Sensors

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The precise three-dimensional measurement of fuel nozzles is of great significance to assess the manufacturing accuracy and improve the spray and atomization performance. This paper proposes an improved fast shape from focus (SFF) method for three-dimensional measurement of key features of fuel nozzles. In order to ensure the measurement accuracy and efficiency of the SFF, the dispersion of the measured points from a standard flat plane was used to select the optimal combination of the focus measure operator, window size and sampling step size. In addition, an approximate method for the focus measure interval is proposed to improve the measurement efficiency, which uses the peak region of the central pixel to replace the peak region of other pixels. The results show that the proposed method decreased the average computation time of the focus measure by 79.19% for the cone section and by 38.30% for the swirl slot. Compared with a reference laser scanning microscope, the measurement error in length is within 10 μm and the error in angle is within a maximum 0.15°.

show abstract

In-situ thickness measurement of epoxy molding compound in semiconductor package products using a Terahertz-Time of Flight System

Cited by 20 publications

References 19 publications

Design and Performance of Extraordinary Low-Cost Compact Terahertz Imaging System Based on Electronic Components and Paraffin Wax Optics

Design and Performance of Extraordinary Low-Cost Compact Terahertz Imaging System Based on Electronic Components and Paraffin Wax Optics

THz-TDS for IC packaging material changes detection under real-world conditions

An Improved Shape from Focus Method for Measurement of Three-Dimensional Features of Fuel Nozzles

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