Epoxy Die Attach Combined With Face-Up Die Bonding for Improved XYZ Placement Accuracy

2021 ◽  
Author(s):  
Tadeh Avanessian ◽  
Jim Clatterbaugh ◽  
Robin L. Zinsmaster ◽  
Leyla Hashemi
Keyword(s):  
Flip Chip ◽  
Coefficient Of Thermal Expansion ◽  
Test Results ◽  
Microelectronics Packaging ◽  
Bond Failure ◽  
Die Attach ◽  
Before And After ◽  
Placement Accuracy ◽  
Die Bonding ◽  
Heated Stage

Abstract Epoxy die attach is widely used in microcircuit assembly and enjoys advantages such as ease of deposition, fast curing, reworkability, and non-toxicity. These qualities also make it suitable for automated mass production. However, this method falls short when high placement accuracy is desired as the die can shift on uncured epoxy leading to die displacement from its original location. Gold to gold face-up bonding is another method utilized in microelectronics packaging given its proven bonding reliability and high placement accuracy for small devices. Nevertheless, it is difficult to achieve a reliable bond using this method for relatively larger devices. The nonplanarity of the bonding collet or the variation in the height of the gold bumps results in a tilted die attach and/or a weak bond between the die and the substrate. Moreover, CTE (Coefficient of Thermal Expansion) mismatch between the die, the gold bumps, and/or the substrate leads to bond failure due to temperature fatigue. This paper discusses a hybrid method to take advantage of the strengths of both methods mentioned above, culminating in a reliable process with high XYZ placement accuracy. To apply this method, epoxy is first dispensed on a gold-plated substrate. Using a flip chip machine, samples with plated gold bumps on their ground side are then placed on the substrate. The gold bumps are mainly used as targets and stand-offs to improve the placement accuracy and to control epoxy glue-line thickness. The force applied on the die, the time the force is applied, and the substrate temperature are controlled for optimum die attach. Moreover, along with the force applied by the vacuum tip, epoxy is partially cured on the flip chip machine heated stage before it is moved to an oven to complete the cure process. Die shear test results before and after temperature conditioning are compared with standard epoxy die attach and gold to gold face-up bonding for identical samples and the advantages are discussed.

Die to Die and Die To Wafer Bonding Solution for High Density, Fine Pitch Micro-Bumped Die

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 002251-002284 ◽  
Author(s):  
Gilbert Lecarpentier ◽  
Joeri De Vos
Keyword(s):  
Wafer Bonding ◽  
Flip Chip ◽  
High Accuracy ◽  
High Density ◽  
Size Reduction ◽  
Direct Impact ◽  
3 Dimensional ◽  
Fine Pitch ◽  
Placement Accuracy ◽  
Die Bonding

Higher density interconnection using 3-Dimensional technology implies a pitch reduction and the use of micro-bumps. The micro-bump size reduction has a direct impact on the placement accuracy needed on the die placement and flip chip bonding equipment. The paper presents a Die-to-Die and Die-to-Wafer, high accuracy, die bonding solution illustrated by the flip chip assembly of a large 2x2cm die consisting of 1 million 10 μm micro-bumps at 20 μm pitch

Effect of Material Properties and Thickness of Die Attach on Delamination of Die Attach/Die Paddle Interface in Electronic Package

2010 ◽  
Author(s):  
Chia-Lung Chang ◽  
Po-Hsien Li
Keyword(s):  
Material Properties ◽  
Coefficient Of Thermal Expansion ◽  
Damage Parameter ◽  
Stress And Strain ◽  
Thermal Expansion Mismatch ◽  
The Finite Element Method ◽  
Electronic Package ◽  
Die Attach ◽  
Encapsulation Process ◽  
Die Bonding

The electronic package is a multi-layered structure that is consisted of several materials. Under the temperature loadings, the interfacial stresses between layered components are generated due to the CTE (coefficient of thermal expansion) mismatch between different materials. In die bonding process, the void or defect might exist at the die attach/die paddle interface. The void cause further delamination on the interface during the encapsulation process. In this study, the finite element method is used to construct the model of electronic package with a void on the die attach/die paddle interface. The energy release rate based on J integration, which is calculated by the stress and strain around the tip of crack, is used as a damage parameter to predict the tendency of further delamination during encapsulation. Effect of material properties (Young’s modulus and CTE) and die attach thickness on delamination of die attach/die paddle interface in package during encapsulation is studied.

An Optimization of Two-Steps Curing Profile to Eliminate Voids Formation in Underfill Epoxy for Hi-CTE Flip Chip Packaging

2010 ◽  
Vol 97-101 ◽  
pp. 23-27 ◽  
Author(s):  
Zainudin Kornain ◽  
Azman Jalar ◽  
Rozaidi Rashid ◽  
Shahrum Abdullah
Keyword(s):  
Flip Chip ◽  
Coefficient Of Thermal Expansion ◽  
Ball Grid Array ◽  
Statistic Analysis ◽  
Curing Process ◽  
Ceramic Ball ◽  
Die Attach ◽  
Ball Grid Array Package ◽  
Flip Chip Packaging ◽  
The Impact

Underfilling is the preferred process to reduce the impact of the thermal stress that results from the mismatch in the coefficient of thermal expansion (CTE) between the silicon chip and the substrate in Flip Chip Packaging. Voids formation in underfill is considered as failure in flip chip manufacturing process. Voids formation possibly caused by several factors such as poor soldering and flux residue during die attach process, voids entrapment due moisture contamination, dispense pattern process and setting up the curing process. This paper presents the optimization of two steps curing profile in order to reduce voids formation in underfill for Hi-CTE Flip Chip Ceramic Ball Grid Array Package (FC-CBGA). A C-Mode Scanning Aqoustic Microscopy (C-SAM) was used to scan the total count of voids after curing process. Statistic analysis was conducted to analyze the suitable curing profile in order to minimize or eliminate the voids formation. It was shown that the two steps curing profile provided solution for void elimination.

Analysis of Two Electrical Failures Caused by Die Attach of Exposed Pad Package

2014 ◽  
Author(s):  
Jinglong Li ◽  
Motohiko Masuda ◽  
Yi Che ◽  
Miao Wu
Keyword(s):  
Bonding Process ◽  
Die Attach ◽  
Die Bonding ◽  
Generic Analysis

Abstract Die attach is well known in die bonding process. Its electrical character is simple. But some failures caused by die attach are not so simple. And it is not proper to analyze by a generic analysis flow. The analysis of two failures caused by die attach are presented in this paper.

Manufacturing In-Line Whole Wafer Focused Ion Beam (FIB) Memory Address Descramble Verification

2008 ◽  
Author(s):  
Steven B. Herschbein ◽  
Hyoung H. Kang ◽  
Scott L. Jansen ◽  
Andrew S. Dalton
Keyword(s):  
Flip Chip ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Random Access ◽  
Cell Counting ◽  
Test Results ◽  
Laboratory Procedure ◽  
Memory Array ◽  
Dual Beam ◽  
Process Level

Abstract Test engineers and failure analyst familiar with random access memory arrays have probably encountered the frustration of dealing with address descrambling. The resulting nonsequential internal bit cell counting scheme often means that the location of the failing cell under investigation is nowhere near where it is expected to be. A logical to physical algorithm for decoding the standard library block might have been provided with the design, but is it still correct now that the array has been halved and inverted to fit the available space in a new processor chip? Off-line labs have traditionally been tasked with array layout verification. In the past, hard and soft failures could be induced on the frontside of finished product, then bitmapped to see if the sites were in agreement. As density tightened, flip-chip FIB techniques to induce a pattern of hard fails on packaged devices came into practice. While the backside FIB edit method is effective, it is complex and expensive. The installation of an in-line Dual Beam FIB created new opportunities to move FA tasks out of the lab and into the FAB. Using a new edit procedure, selected wafers have an extensive pattern of defects 'written' directly into the memory array at an early process level. Bitmapping of the RAM blocks upon wafer completion is then used to verify correlation between the physical damaged cells and the logical sites called out in the test results. This early feedback in-line methodology has worked so well that it has almost entirely displaced the complex laboratory procedure of backside FIB memory array descramble verification.

Effects of Backside Circuit Edit on Transistor Characteristics

2007 ◽  
Author(s):  
R.K. Jain ◽  
T. Malik ◽  
T.R. Lundquist ◽  
Q.S. Wang ◽  
R. Schlangen ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Flip Chip ◽  
Intrinsic Parameters ◽  
Chip Type ◽  
Device Structures ◽  
Before And After ◽  
Silicon Device ◽  
Metal Layers

Abstract Backside circuit edit techniques on integrated circuits (ICs) are becoming common due to increase number of metal layers and flip chip type packaging. However, a thorough study of the effects of these modifications has not been published. This in spite of the fact that the IC engineers have sometimes wondered about the effects of backside circuit edit on IC behavior. The IC industry was well aware that modifications can lead to an alteration of the intrinsic behavior of a circuit after a FIB edit [1]. However, because alterations can be controlled [2], they have not stopped the IC industry from using the FIB to successfully reconfigure ICs to produce working “silicon” to prove design and mask changes. Reliability of silicon device structures, transistors and diodes, are investigated by monitoring intrinsic parameters before and after various steps of modification.

Sunlight exposure: the effects on the performance of paragliding fabric

2018 ◽  
Vol 69 (05) ◽  
pp. 381-389
Author(s):  
MENGÜÇ GAMZE SÜPÜREN ◽  
TEMEL EMRAH ◽  
BOZDOĞAN FARUK
Keyword(s):  
Mechanical Properties ◽  
Aging Process ◽  
Air Permeability ◽  
Sunlight Exposure ◽  
Test Results ◽  
Coating Materials ◽  
Strength Tests ◽  
Before And After ◽  
The Relationship ◽  
Dark Blue

This study was designed to explore the relationship between sunlight exposure and the mechanical properties of paragliding fabrics which have different colors, densities, yarn counts, and coating materials. This study exposed 5 different colors of paragliding fabrics (red, turquoise, dark blue, orange, and white) to intense sunlight for 150 hours during the summer from 9:00 a.m. to 3:00 p.m. for 5 days a week for 5 weeks. Before and after the UV radiation aging process, the air permeability, tensile strength, tear strength, and bursting strength tests were performed. Test results were also evaluated using statistical methods. According to the results, the fading of the turquoise fabric was found to be the highest among the studied fabrics. It was determined that there is a significant decrease in the mechanical properties of the fabrics after sunlight exposure. After aging, the fabrics become considerably weaker in the case of mechanical properties due to the degradation in both the dyestuff and macromolecular structure of the fiber

scholarly journals An Empirical Study on the Application of Cooperative Learning to Comprehensive English Classes in a Chinese Independent College

2017 ◽  
Vol 10 (2) ◽  
pp. 94
Author(s):  
Ji Meng
Keyword(s):  
Cooperative Learning ◽  
Empirical Study ◽  
Test Results ◽  
Independent College ◽  
Language Competence ◽  
English Classes ◽  
Academic Level ◽  
Before And After ◽  
Posttest Questionnaire ◽  
Positive Impacts

This research investigated a comparison between the effect of cooperative learning and lecture teaching on Comprehensive English classes in a Chinese Independent College. An empirical study for two semesters was carried out in the forms of pretest, posttest, questionnaire and interviews. While control class was taught in the conventional way, experiment class was instructed based on cooperative base groups with positive interdependence structured on purpose. Compared with traditional instructions, cooperative learning as pedagogy can improve students’ performance on course exams, but not necessarily their language competence as shown in national English competency tests taken before and after the experiement. Test results also indicate students from experiment class who excelled in competency test outnumbered those from control class, revealing that cooperative learning has positive impacts especially on students at a relatively higher academic level. Questionaire results show that students are most inclined to agree they have more chances to practice the language in a cooperative environment.

Characteristics of Phenomena in Powders Type RE2Zr2O7-Al2O3 in High Temperature Annealing Conditions

2011 ◽  
Vol 312-315 ◽  
pp. 583-588 ◽  
Author(s):  
Grzegorz Moskal ◽  
Lucjan Swadźba ◽  
Marek Hetmańczyk ◽  
Bartosz Witala
Keyword(s):  
High Temperature ◽  
Perovskite Oxide ◽  
Differential Scanning Calorimetric ◽  
Test Results ◽  
Dsc Analysis ◽  
Annealing Conditions ◽  
Before And After ◽  
Influence Of Temperature On ◽  
Dta Analysis ◽  
Type Bond

The paper presents test results and characterizes the structural stability of powders, which form a mixture of aluminium oxide (Al2O3) and gadolinium, based on rare earth zirconates. This mixture is provided to create thermal barrier coatings (TBCs) by spraying. The purpose of the tests was to determine the influence of temperature on reactions, occurring between those powders within a temperature range from 25°C to 1500°C, while such conditions were to simulate the conditions, which occur during creation of TBCs and they give an answer to the question concerning mutual reactivity of the powders. The requirements for new materials, provided to spray the TBCs, indicate the necessity to prepare the materials, which do not show tendency towards reactions with the Al2O3, formed during oxidation of Ni (Co) CrAlY, while this reaction is of type bond coat. The tests included differential scanning calorimetric (DSC) analysis and differential thermal analysis (DTA) of powder mixtures. Diffraction analysis was also performed before and after the tests have been finished. The DSC analysis results, obtained at a range of high temperature, did not show any thermal effects, which indicate a low level of mutual reactivity of the powders. However, the DTA analysis suggests presence of such effects at temperature close to 1300°C, and it indicates the necessity to verify exactly the obtained results. Results of the XRD measurement showed that after annealing process already at 1100°C the perovskite oxide of GdAlO3 was present.

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