Use of Wafer Applied Underfill for 3D Stacking

2011 ◽  
Vol 2011 (1) ◽  
pp. 000008-000016 ◽  
Author(s):  
Antonio La Manna ◽  
K. J. Rebibis ◽  
C. Gerets ◽  
E. Beyne

A key element for improving 3D stacking reliability is the choice of the right Underfill materials. The Underfill is a specialized adhesive that has the main purposes of locking top and bottom dies; it must fill the gap between bumps and between dies, while reducing the differential movement that would occur during thermal cycling. Traditional underfill processes are based on local dispensing after solder bump reflow (Capillary dispensing), or before flip chip operation with no need of reflow (No Flow Underfill, NUF). In case of 3D stacking, such processes present some limitations: need of a dispensing area (die size increase); material flowing (spacing between dies) and cost (low throughput). After an introduction on typical underfill applications like die-to-package and die-die assembly, we report the work done to assess the properties of several Wafer Applied Underfill (WAUF) materials and their integration in 3D stacking. These materials have been initially applied on silicon wafers in order to assess the minimum achievable thickness and the material uniformity. The wafers have been coated by using different methods: spin coating and film lamination. After this initial assessment, the most promising materials have been used for 3D stacking. The test vehicle used has Cu/Sn μbumps with a pitch of 40μm. The quality of the materials is judged by electrical test, SAM (Surface Acoustic Microscope) and X-SEM (Scanning Electron Microscope).

2012 ◽  
Vol 9 (1) ◽  
pp. 10-18
Author(s):  
Antonio La Manna ◽  
K. J. Rebibis ◽  
C. Gerets ◽  
E. Beyne

A key element for improving 3D IC stacking and packaging reliability is the choice of the right underfill (UF) material. The underfill is a specialized adhesive whose main purpose is locking together the top and bottom dice; it must fill the gap between bumps and between dice, while reducing the differential movement that would occur during thermal cycling. Traditional underfill processes are based on local dispensing after solder bump reflow (i.e., capillary dispensing), or before flip chip operation with no need of reflow (no flow underfill, NUF). In case of 3D stacking, such processes present some limitations: the need for a dispensing area (die size increase); material flow (spacing between dice), and cost (low throughput). After an introduction on typical underfill applications such as die-to-package and die-to-die assembly, we report the work done to assess the properties of several wafer applied underfill (WAUF) materials and their integration in 3D stacking. These materials were initially applied on silicon wafers in order to assess the minimum achievable thickness and material uniformity. The wafers were coated with different methods: spin coating and film lamination. After this initial assessment, the most promising materials were used for 3D stacking. The test vehicle used has Cu/Sn microbumps with a pitch of 40 μm. The quality of the materials is judged by electrical test, SAM (surface acoustic microscope), and X-SEM (scanning electron microscope).


2000 ◽  
Author(s):  
Dathan S. Erdahl ◽  
Sheng Liu ◽  
I. Charles Ume

Abstract Because the trend in electronic interconnection technology is toward the development of solder bump technologies, that include flip chips, chip scale packages, multi-chip modules (MCMs), and ball grid array (BGA) packages, solder bump inspection methods must be developed to allow rapid, accurate, and high resolution on-line inspection of joint quality. Although traditional methods can detect some manufacturing defects, they do not actually test the mechanical quality of the connection. A novel solder-joint inspection system has been developed based on laser ultrasound and interferometric techniques. A pulsed laser generates ultrasound on the chip’s surface and the whole chip is excited into vibration modes. An interferometer is used to measure the vibration displacement of the chip’s surface. Solder joints with different qualities cause different vibration responses, acting as constraints on the system. The system was used to inspect the quality of solder joints on a group of flip chips mounted on FR-4 substrates, and the results show the ability of the system to detect defects such as missing solder balls, cracked chips, and gross misalignment.


Author(s):  
Nataliia Kharytonova ◽  
Olha Mykolaienko ◽  
Tetyana Lozova

Greening of roads contributes to the protection of roads and their elements from influence of adverse weather and climatic factors; it includes the measures for improvement and landscaping of roads, ensures the protection of roadside areas from transport pollution, provides visual orientation of drivers. The solution of these issues will ensure creation and maintenance of safe and comfortable conditions for travelers. Green plantings in the right-of-way road area include woody, bushy, flower and grass vegetation of natural and artificial origin. For proper operation of public roads and satisfaction of other needs of the industry, there may be the need in removing the greenery. The reason for the removal of greenery in the right-of-way road area may be due to the following factors: construction of the architectural object, widening of the motor road, repair works in the security zone of overhead power lines, water supply, drainage, heating, telecommunications facilities, cutting of hazardous, dry and fautal trees, as well as self-grown and brushwood trees with a root neck diameter not exceeding 5 cm, elimination of the consequences of natural disasters and emergencies. The removal of plantations in the right-of-way area is executed in order to ensure traffic safety conditions and to improve the quality of plantations composition and their protective properties. Nowadays, in Ukraine there is no clear procedure for issuing permits for removing of such plantations. In order to resolve this issue, there is a need in determining the list of regulations in the area of forest resources of Ukraine and, if needed, the list of regulatory acts that have to be improved; to prepare a draft of the regulatory legal act that would establish the procedure of plantations cutting, the methodology of their condition determination, recovery costs determination, the features of cutting. Keywords: plantations, cutting, right-of-way, woodcutting permit, order.


Author(s):  
Leen Adeeb Fakhoury ◽  
Naif Adel Haddad

This paper attempts to present and discuss the outcome of the results of the key different studies and projects carried out at Salt and at Irbid historic cores.  It focuses on the executed urban heritage projects undertaken mainly by the Ministry of Tourism and Antiquities (MoTA) of Jordan in the last two decades. It discusses their different aspects through initial assessment of the loss and degradation of the cultural heritage assets of the two cities; the fragmentation and lack of connectivity between the modern and historic cores; issues of sustainability of architectural and urban heritage projects i.e. tourism planning and conservation; and reuse projects at the historic cores in relation to cultural, physical factors and development needs. It also addresses the behaviour and characteristics of the urban regeneration process in those two historic cities, starting from their documentation to examination of the different aspects of the currently adopted urban practices and policies, and their impact on the existing urban heritage, depending on the specific identity of the respective historic cores. Finally, it aims to define the main constraints and challenges for the reuse of the existing heritage fabric including the local community quality of life, while building on sustainable heritage activities accommodating tourism opportunities. This will give, at least, some indications from which we can identify a use or combination of uses, and practical steps needed for successful heritage conservation actions in Jordan, in order to retain the cultural significance of the place.


Author(s):  
Tita Mila Mustofani ◽  
Ita Hartinah

This writing aims to help teachers to increase motivation, activity, creativity, and critical thinking of students in solving problems in class. The way to increase student motivation in learning in class is to choose the right learning model with ongoing learning material. One learning model that increases students' creativity and critical thinking in problem solving is a Problem Based Learning (PBL) learning model. To improve students' insights in order to easily solve problems there is a need to do tasks, if students do not do the task then they must accept the agreed upon consequences when making learning contracts, thus modifying the Problem Based Learning (PBL) learning model with task strategies and forced. The results of the modification of learning with the Problem Based Learning (PBL) learning model through forced and forced strategies are expected to improve the learning process so that students become more disciplined and do not waste time doing assignments. The advantages of modifying the Problem Based Learning (PBL) learning model with task and forced learning strategies are increasing student learning motivation, improving the quality of learning, training students' understanding by giving assignments continuously, teaching discipline to students in order to be accountable for tasks assigned, and reducing laziness in students.


Author(s):  
George F. Gaut

Abstract Access to the solder bump and under-fill material of flip-chip devices has presented a new problem for failure analysts. The under-fill and solder bumps have also added a new source for failure causes. A new tool has become available that can reduce the time required to analyze this area of a flip-chip package. By using precision selective area milling it is possible to remove material (die or PCB) that will allow other tools to expose the source of the failure.


Author(s):  
Gwee Hoon Yen ◽  
Ng Kiong Kay

Abstract Today, failure analysis involving flip chip [1] with copper pillar bump packaging technologies would be the major challenges faced by analysts. Most often, handling on the chips after destructive chemical decapsulation is extremely critical as there are several failure analysis steps to be continued such as chip level fault localization, chip micro probing for fault isolation, parallel lapping [2, 3, 4] and passive voltage contrast. Therefore, quality of sample preparation is critical. This paper discussed and demonstrated a quick, reliable and cost effective methodology to decapsulate the thin small leadless (TSLP) flip chip package with copper pillar (CuP) bump interconnect technology.


2020 ◽  
Vol 1 (10(79)) ◽  
pp. 12-18
Author(s):  
G. Bubyreva

The existing legislation determines the education as "an integral and focused process of teaching and upbringing, which represents a socially important value and shall be implemented so as to meet the interests of the individual, the family, the society and the state". However, even in this part, the meaning of the notion ‘socially significant benefit is not specified and allows for a wide range of interpretation [2]. Yet the more inconcrete is the answer to the question – "who and how should determine the interests of the individual, the family and even the state?" The national doctrine of education in the Russian Federation, which determined the goals of teaching and upbringing, the ways to attain them by means of the state policy regulating the field of education, the target achievements of the development of the educational system for the period up to 2025, approved by the Decree of the Government of the Russian Federation of October 4, 2000 #751, was abrogated by the Decree of the Government of the Russian Federation of March 29, 2014 #245 [7]. The new doctrine has not been developed so far. The RAE Academician A.B. Khutorsky believes that the absence of the national doctrine of education presents a threat to national security and a violation of the right of citizens to quality education. Accordingly, the teacher has to solve the problem of achieving the harmony of interests of the individual, the family, the society and the government on their own, which, however, judging by the officially published results, is the task that exceeds the abilities of the participants of the educational process.  The particular concern about the results of the patriotic upbringing served as a basis for the legislative initiative of the RF President V. V. Putin, who introduced the project of an amendment to the Law of RF "About Education of the Russian Federation" to the State Duma in 2020, regarding the quality of patriotic upbringing [3]. Patriotism, considered by the President of RF V. V. Putin as the only possible idea to unite the nation is "THE FEELING OF LOVE OF THE MOTHERLAND" and the readiness for every sacrifice and heroic deed for the sake of the interests of your Motherland. However, the practicing educators experience shortfalls in efficient methodologies of patriotic upbringing, which should let them bring up citizens, loving their Motherland more than themselves. The article is dedicated to solution to this problem based on the Value-sense paradigm of upbringing educational dynasty of the Kurbatovs [15].


Author(s):  
Troncone Raffaella ◽  
Coda Marco

Evaluation is at the basis of any social context where all individuals are simultaneously "evaluated" and "evaluators" in all areas of daily life. The goal of a good evaluation system is to encourage staff to do "Good Health" through the provision of quality prevention, diagnosis, treatment and rehabilitation services. The main reasons that lead to the evaluation of the personnel lie in the inevitable and primary importance of the human resource in achieving the corporate objectives, and by the pressing need for the quality of the service provided to the citizen, as well as the legitimate need of the employee to differentiate, clarifying its specificities and its own individual contribution to the general objectives of the company. In the working context, the "personnel evaluation" assumes a fundamental importance, if managed with the right criteria, in order to make the employee not a simple pawn to move and manage for use and consumption of the organization, but an integral part of the organization itself.


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