Thermal Control of Interfaces for Microelectronic Packaging

1998 ◽  
Vol 515 ◽  
Author(s):  
E. E. Marotta ◽  
B. Hana
Keyword(s):  
Thermal Performance ◽  
Flip Chip ◽  
Printed Circuit Boards ◽  
Thermal Stresses ◽  
Experimental Studies ◽  
Thermal Control ◽  
Thermal Contact Conductance ◽  
Microelectronic Packaging ◽  
Chip Technology ◽  
Operating Temperatures

ABSTRACTThe continuous miniaturization of electronic devices places an ever-increasing importance on the thermal management of electronic systems and its subcomponents. The increased power densities and heat generation, due to the miniaturization of the device line features, may lead to higher operating temperatures and greater warpage between the silicon device and its organic carrier. The higher operating temperature may result from the degradation of the overall thermal performance. These additive effects will also lead to an increasing number of thermally induced failures, which will be further magnified when future microelectronic packaging incorporates flip-chip technology.The higher operating temperatures within microelectronic systems result from inadequate dissipation of the heat generated, while the warpage effect is caused by the mismatch between the thermal coefficients of expansion (ICE) induced by thermal stresses. Often these high temperatures result from the thermal resistance between subcomponents, such as between the contacting surfaces of laminated printed circuit boards, device/epoxy cement and heat spreader (i.e., finned heat sink or heat pipe), and any other metallic or non-metallic interstitial material employed between contacting interfaces.Published experimental data of potential coatings, adhesives, and elastomeric gaskets is presented that can improve the thermal contact conductance of contacting surfaces within microelectronic systems. In addition, recommendations for future analytical and experimental studies of the mnechanistic principles, which control thermal performance of interstitial materials, are discussed for non-uniform pressure distribution.

The effect of underfill on thermal stresses on logic ASIC and its electrical performance

2017 ◽  
Vol 2017 (DPC) ◽  
pp. 1-20
Author(s):  
Babak Talebanpour ◽  
Doug Link
Keyword(s):  
Frequency Shift ◽  
Flip Chip ◽  
Thermal Stresses ◽  
Electrical Performance ◽  
Shear Stresses ◽  
Normal Stresses ◽  
Clock Frequency ◽  
Chip Technology ◽  
Solder Bumps ◽  
Solder Reflow

Flip chip technology is widely used today to support the demand for high interconnect density of modern microelectronic circuits. Conventionally, solder bumps have provided the electrical and mechanical connection between the chip and the substrate. The solder bumps are prone to fatigue and failure especially in large chips and/or mobile devices. Conventional underfilling process which consists of flowing an epoxy under the chip and curing it after the flip chip connections are made mechanically supports the assembly, significantly reducing the shear stresses on the bumps and minimizing the chip warpage due to thermal stresses. However, underfill also has side effects. The flow of underfill depends on a lot of parameters usually can be incomplete or containing a lot of voids, inconsistent underfill results in unpredictable overall durability or manufacturing survivability. Furthermore, underfilling introduces certain components of stress, this form of stress can have adverse effect on the electrical performance of the die if it occurs close to stress sensitive parts. In this study, the effect of underfilling and its quality on the clock frequency shift of a DSP (Digital Signal Processor) chip used by Starkey Hearing Technologies is investigated. Clock frequency measurements after a solder reflow process has been compared for different underfill materials, and underfill quality. Finite element analysis was implemented to assess the stress transferred to the clock circuit on the die and examine how existence of underfill, bump height, location of bumps, and underfill voids affect the stress. The following results have been concluded based on the work presented in this paper:The conventional underfilling process for dies with very small standoff heights can be very in consistent, strongly depending on the gap uniformity, flex traces, cleanliness of the package after solder reflow, etc. large percentage of delamination and voids can occur. The voids and delamination can cause solder extrusion as well as inconsistent stress distribution on the die.Although underfilling causes large normal stresses on the die, it reduces the effective stress on the die which can translate to less warpage and the problems associated with it.The height of the bumps does not strongly affect the amount of stress build up on the die if it does not compromise a uniform underfill.Relocation of the bumps away from the clock circuit significantly reduces the stress on the clock, and it has been shown to minimize the clock shift in practice. A minimum amount of distance between the clock circuit and solder bumps should be considered when DSP layout are designed.If the clock circuit surface is not in contact with the underfill, normal stresses will not be transferred to the clock circuit minimizing the clock frequency shift. The best approach to implement this method is wafer-level underfill technique. The underfill will be applied at the wafer fab and precision lasers can cut the underfill laminate at desired locations. This process can guarantee support for the die by a uniform underfill, while stress sensitive parts will be protected against unwanted thermal stresses.

A High Temperature SOI-CMOS Chipset Focusing Sensor Electronics for Operating Temperatures up to 300 °C

2021 ◽  
Vol 2021 (HiTEC) ◽  
pp. 000018-000024
Author(s):  
Holger Kappert ◽  
Sebastian Braun ◽  
Norbert Kordas ◽  
Andre Kosfeld ◽  
Alexander Utz ◽  
...  
Keyword(s):  
High Temperature ◽  
Flip Chip ◽  
Mechanical Load ◽  
Industrial Processes ◽  
Sensor Systems ◽  
Integrated Sensor ◽  
Chip Technology ◽  
Operating Temperatures ◽  
Silver Sintering ◽  
Soi Cmos

Abstract Sensors are key elements for capturing environmental properties and are increasingly important in the industry for the intelligent control of industrial processes. While in many everyday objects highly integrated sensor systems are already state of the art, the situation in an industrial environment is clearly different. Frequently the use of sensor systems is impossible, because the extreme ambient conditions of industrial processes like high operating temperatures or strong mechanical load do not allow a reliable operation of sensitive electronic components. Fraunhofer is running the Lighthouse Project ‘eHarsh’ to overcome this hurdle. In the course of the project an integrated sensor readout electronic has been realized based on a set of three chips. A dedicated sensor frontend provides the analog sensor interface for resistive sensors typically arranged in a Wheatstone configuration. Furthermore, the chipset includes a 32-bit microcontroller for signal conditioning and sensor control. Finally, it comprises an interface chip including a bus transceiver and voltage regulators. The chipset has been realized in a high temperature 0.35 micron SOI-CMOS technology focusing operating temperatures up to 300 °C. The chipset is assembled on a multilayer ceramic LTCC-board using flip chip technology. The ceramic board consists of 4 layers with a total thickness of approx. 0.9 mm. The internal wiring is based on silver paste while external contacts were alternatively manufactured in silver (sintering/soldering) or in gold-alloys (wire bonding). As interconnection technology, silver sintering has been applied. It has already been shown that a significant increase in lifetime can be reached by using silver sintering for die attach applications. Using silver sintering for flip chip technology is a new and challenging approach. By adjusting the process parameter geared to the chipset design and the design of the ceramic board high quality flip chip interconnects can be generated.

An Experimental Study to Show the Effect of Thermal Stress on Thermal Contact Conductance at Sub-megapascal Contact Pressures

2010 ◽  
Vol 132 (9) ◽  
Author(s):  
Prashant Misra ◽  
J. Nagaraju
Keyword(s):  
Thermal Stress ◽  
Contact Pressure ◽  
Thermal Stresses ◽  
Thermal Contact ◽  
Experimental Studies ◽  
Thermal Contact Conductance ◽  
Large Temperature ◽  
Contact Conductance ◽  
Closed Contact ◽  
Contact Pressures

Experimental studies are presented to show the effect of thermal stresses on thermal contact conductance (TCC) at low contact pressures. It is observed that in a closed contact assembly, contact pressure acting on the interface changes with the changing temperature of contact members. This change in contact pressure consequently causes variations in the TCC of the junction. A relationship between temperature change and the corresponding magnitude of developed thermal stress in a contact assembly is determined experimentally. Inclusion of a term called temperature dependent load correction factor is suggested in the theoretical model for TCC to make it capable of predicting TCC values more accurately in contact assemblies that experience large temperature fluctuations.

Thin-Die Flip Chip Physical-FA Process Flow

2002 ◽  
Author(s):  
Andrew J. Komrowski ◽  
N. S. Somcio ◽  
Daniel J. D. Sullivan ◽  
Charles R. Silvis ◽  
Luis Curiel ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Failure Analysis ◽  
Flip Chip ◽  
Semiconductor Industry ◽  
Organic Substrate ◽  
Fault Isolation ◽  
Preparation Methods ◽  
Chip Technology ◽  
Isolation Test ◽  
Sample Preparation Methods

Abstract The use of flip chip technology inside component packaging, so called flip chip in package (FCIP), is an increasingly common package type in the semiconductor industry because of high pin-counts, performance and reliability. Sample preparation methods and flows which enable physical failure analysis (PFA) of FCIP are thus in demand to characterize defects in die with these package types. As interconnect metallization schemes become more dense and complex, access to the backside silicon of a functional device also becomes important for fault isolation test purposes. To address these requirements, a detailed PFA flow is described which chronicles the sample preparation methods necessary to isolate a physical defect in the die of an organic-substrate FCIP.

Failure Analysis of Flip-Chip Interconnections Through Acoustic Microscopy

1996 ◽  
Author(s):  
O. Diaz de Leon ◽  
M. Nassirian ◽  
C. Todd ◽  
R. Chowdhury
Keyword(s):  
Failure Analysis ◽  
Large Scale ◽  
Flip Chip ◽  
Ultrasonic Waves ◽  
Acoustic Microscopy ◽  
Acoustic Microscope ◽  
Chip Technology ◽  
Ball Joints ◽  
Non Destructive ◽  
Scanning Acoustic Microscope

Abstract Integration of circuits on semiconductor devices with resulting increase in pin counts is driving the need for improvements in packaging for functionality and reliability. One solution to this demand is the Flip- Chip concept in Ultra Large Scale Integration (ULSI) applications [1]. The flip-chip technology is based on the direct attach principle of die to substrate interconnection.. The absence of bondwires clearly enables packages to become more slim and compact, and also provides higher pin counts and higher-speeds [2]. However, due to its construction, with inherent hidden structures the Flip-Chip technology presents a challenge for non-destructive Failure Analysis (F/A). The scanning acoustic microscope (SAM) has recently emerged as a valuable evaluation tool for this purpose [3]. C-mode scanning acoustic microscope (C-SAM), has the ability to demonstrate non-destructive package analysis while imaging the internal features of this package. Ultrasonic waves are very sensitive, particularly when they encounter density variations at surfaces, e.g. variations such as voids or delaminations similar to air gaps. These two anomalies are common to flip-chips. The primary issue with this package technology is the non-uniformity of the die attach through solder ball joints and epoxy underfill. The ball joints also present defects as open contacts, voids or cracks. In our acoustic microscopy study packages with known defects are considered. It includes C-SCAN analysis giving top views at a particular package interface and a B-SCAN analysis that provides cross-sectional views at a desired point of interest. The cross-section analysis capability gives confidence to the failure analyst in obtaining information from a failing area without physically sectioning the sample and destroying its electrical integrity. Our results presented here prove that appropriate selection of acoustic scanning modes and frequency parameters leads to good reliable correlation between the physical defects in the devices and the information given by the acoustic microscope.

Spray Cooling for Time Resolved Emission Measurements of ICs

2004 ◽  
Author(s):  
Rama R. Goruganthu ◽  
David Bethke ◽  
Shawn McBride ◽  
Tom Crawford ◽  
Jonathan Frank ◽  
...  
Keyword(s):  
Heat Flux ◽  
Thermal Performance ◽  
Flip Chip ◽  
Cooling System ◽  
Spray Cooling ◽  
Junction Temperature ◽  
Maximum Temperature ◽  
Uniform Heat Flux ◽  
High Heat Flux ◽  
Time Resolved

Abstract Spray cooling is implemented on an engineering tool for Time Resolved Emission measurements using a silicon solid immersion lens to achieve high spatial resolution and for probing high heat flux devices. Thermal performance is characterized using a thermal test vehicle consisting of a 4x3 array of cells each with a heater element and a thermal diode to monitor the temperature within the cell. The flip-chip packaged TTV is operated to achieve uniform heat flux across the die. The temperature distribution across the die is measured on the 4x3 grid of the die for various heat loads up to 180 W with corresponding heat flux of 204 W/cm2. Using water as coolant the maximum temperature differential across the die was about 30 °C while keeping the maximum junction temperature below 95 °C and at a heat flux of 200 W/cm2. Details of the thermal performance of spray cooling system as a function of flow rate, coolant

Analysis of the results of medium-energy electrons on the protective and thermoregulatory coatings of high-orbit satellites

2018 ◽  
pp. 156-171
Author(s):  
A. M. Shamayev ◽  
M. D. Ozersky
Keyword(s):  
Structural Changes ◽  
Protective Coatings ◽  
Experimental Studies ◽  
Thermal Control ◽  
Space Vehicles ◽  
Medium Energy ◽  
Electrostatic Discharges ◽  
High Orbit ◽  
Thermal Control Coatings ◽  
Solar Batteries

The results of experimental studies of the effect of electron irradiation on K-208 and CMG glasses used for manufacturing protective coatings of solar batteries and thermal control coatings of space vehicles are analyzed. It is shown that the caused electrostatic discharges lead to structural changes in the surfaces of the glasses studied. The goals of further studies of the influence of proton and electronproton effects on the properties of such coatings are outlined. 

scholarly journals Design and Switching Characteristics of Flip-Chip GaN Half-Bridge Modules Integrated with Drivers

2021 ◽  
Vol 11 (15) ◽  
pp. 7057
Author(s):  
Lin Wang ◽  
Zhe Cheng ◽  
Zhi-Guo Yu ◽  
De-Feng Lin ◽  
Zhe Liu ◽  
...  
Keyword(s):  
Flip Chip ◽  
High Electron Mobility Transistors ◽  
Wire Bonding ◽  
High Electron ◽  
Parasitic Inductance ◽  
Switching Performance ◽  
Turn On ◽  
Electron Mobility Transistors ◽  
Chip Technology ◽  
Switching Characteristics

Half-bridge modules with integrated GaN high electron mobility transistors (HEMTs) and driver dies were designed and fabricated in this research. Our design uses flip-chip technology for fabrication, instead of more generally applied wire bonding, to reduce parasitic inductance in both the driver-gate and drain-source loops. Modules were prepared using both methods and the double-pulse test was applied to evaluate and compare their switching characteristics. The gate voltage (Vgs) waveform of the flip-chip module showed no overshoot during the turn-on period, and a small oscillation during the turn-off period. The probabilities of gate damage and false turn-on were greatly reduced. The inductance in the drain-source loop of the module was measured to be 3.4 nH. The rise and fall times of the drain voltage (Vds) were 12.9 and 5.8 ns, respectively, with an overshoot of only 4.8 V during the turn-off period under Vdc = 100 V. These results indicate that the use of flip-chip technology along with the integration of GaN HEMTs with driver dies can effectively reduce the parasitic inductance and improve the switching performance of GaN half-bridge modules compared to wire bonding.

scholarly journals Experimental Investigation and Comparison of the Thermal Performance of Additively and Conventionally Manufactured Heat Exchangers

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 574
Author(s):  
Ana Vafadar ◽  
Ferdinando Guzzomi ◽  
Kevin Hayward
Keyword(s):  
Surface Roughness ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
High Efficiency ◽  
Cooling System ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Experimental Studies ◽  
Manufacturing Method ◽  
Industrial Sectors

Air heat exchangers (HXs) are applicable in many industrial sectors because they offer a simple, reliable, and cost-effective cooling system. Additive manufacturing (AM) systems have significant potential in the construction of high-efficiency, lightweight HXs; however, HXs still mainly rely on conventional manufacturing (CM) systems such as milling, and brazing. This is due to the fact that little is known regarding the effects of AM on the performance of AM fabricated HXs. In this research, three air HXs comprising of a single fin fabricated from stainless steel 316 L using AM and CM methods—i.e., the HXs were fabricated by both direct metal printing and milling. To evaluate the fabricated HXs, microstructure images of the HXs were investigated, and the surface roughness of the samples was measured. Furthermore, an experimental test rig was designed and manufactured to conduct the experimental studies, and the thermal performance was investigated using four characteristics: heat transfer coefficient, Nusselt number, thermal fluid dynamic performance, and friction factor. The results showed that the manufacturing method has a considerable effect on the HX thermal performance. Furthermore, the surface roughness and distribution, and quantity of internal voids, which might be created during and after the printing process, affect the performance of HXs.

Monolithic Thin Film Red LED Active-matrix Micro-display by Flip-chip Technology

2021 ◽  
pp. 1-1
Author(s):  
Peian Li ◽  
Xu Zhang ◽  
Wing Cheung Chong ◽  
Kei May Lau
Keyword(s):  
Thin Film ◽  
Flip Chip ◽  
Active Matrix ◽  
Chip Technology ◽  
Red Led
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