Technical Library | 2017-06-15 00:44:19.0
Ceramics packages are being used in the electronics industry to operate the devices in harsh environments. In this paper we report a study on acoustic imaging technology for nondestructively inspecting underfill layers connecting organic interposers sandwiched between two ceramics substrates.First, we inspected the samples with transmission mode of scanning acoustic tomography (SAT) system, an inspection routine usually employed in assembly lines because of its simpler interpretation criteria: flawed region blocks the acoustic wave and appears darker. In this multilayer sample, this approach does not offer the crucial information at which layer of underfill has flaws. To resolve this issue, we use C-Mode Scanning in reflection mode to image layer by layer utilizing ultrasound frequencies from 15MHz to 120MHz. Although the sample is thick and contains at least 5 internal material interfaces, we are able to identify defective underfill layer interfaces.
Technical Library | 2013-12-05 17:09:03.0
The functionality of electronic devices continues to increase at an extraordinary rate. Simultaneously consumers are expecting even more and in ever smaller packages. One enabler for shrinking electronics has been the flexible circuit board that allows the circuit board to fit a wide variety of shapes. Flexible printed circuits (FPC) have the capability to be very thin and can have unpackaged components directly attached using surface mount technology (SMT) and flip chip on flex technologies. Bare die can also be thinned and attached very close to the circuit board. However one caveat of high density flexible circuit boards with thin die is that they can be very fragile. The use of back side films and underfill can protect the die making circuits more robust. For underfill to work well it requires good adhesion to the circuit board which can mean that flux residues under the die normally must be removed prior to underfilling.
Technical Library | 2016-01-12 11:03:35.0
With the pitch size of interconnect getting finer and finer, the bonding strength between flexible and rigid (e.g. PCB, ceramic) substrates becomes a serious issue because it is not strong enough to meet the customer’s requirement. Capillary underfill has been used to enhance the bonding strength between flexible and rigid substrates, but the enhancement is very limited, particularly for high temperature application. The bonding strength of underfilled flexible/rigid interconnect is dramatically decreased after being used at 180◦C, and the interconnects are weakened by the internal stress caused by the expansion of underfill at high temperatures. In order to resolve reliability issues of the interconnect between flexible/rigid substrates, solder joint encapsulant was implemented into the thermal compression bonding process, which was used to manufacture the interconnect between flexible/rigid substrates. Compared to the traditional process, the strength of the interconnect was doubled and the reliability was significantly improved in high temperature application.
Technical Library | 2024-06-23 22:03:59.0
The melting temperatures of most lead-free solder alloys are somewhat higher than that of eutectic Sn/Pb solder, and many of the alloys tend to wet typical contact pads less readily. This tends to narrow down the fluxing and mass reflow process windows for assembly onto typical organic substrates and may enhance requirements on placement accuracy. Flip chip assembly here poses some unique challenges. The small dimensions provide for particular sensitivities to wetting and solder joint collapse, and underfilling does not reduce the demands on the intermetallic bond strength. Rather, the need to underfill lead to additional concerns in terms of underfill process control and reliability. Relatively little can here be learned from work on regular SMT components, BGAs or CSPs.
Technical Library | 2018-11-14 21:43:14.0
Status of flip chip technology such as wafer bumping, package substrate, flip chip assembly, and underfill will be reviewed in this study. Emphasis is placed on the latest developments of these areas in the past few years. Their future trends will also be recommended. Finally, the competition on flip chip technology will be briefly mentioned.
Technical Library | 2009-09-16 15:13:58.0
The dispensing industry within electronics manufacturing represents a very diverse marketplace indeed; many different materials can be applied in many different ways. One high-growth area in this market is underfill, driven by the explosive demand for hand-held devices (HHDs). This segment is comprised of popular consumer goods, such as cell phones, mp3 players, GPS navigators, PDAs, portable games and ultra-mobile PCs. A new, non-contact dispense technology, known as Streaming, has recently been introduced to specifically address the incumbent needs associated with underfill.
Technical Library | 2016-04-28 14:43:23.0
Underfilling is a long-standing process issued from the micro-electronics that can enhance the robustness and the reliability of first or second-level interconnects for a variety of electronic applications. Its usage is currently spreading across the industry fueled by the decreasing reliability margins induced by the miniaturization and interconnect pitch reduction. (...) This paper will address the control of surface mount under filled assemblies, focusing on applicable inspection techniques and possible options to overcome their limitations.
Technical Library | 2016-01-08 11:56:03.0
Solder joint encapsulant adhesives have been successfully used to enhance the strength of solder joints and improve thermal cycling as well as drop performance in finished products. The use of solder joint encapsulant adhesives can eliminate the need for underfill materials and the underfill process altogether, thus simplifying rework, which results in a lower cost of ownership.Solder joint encapsulant adhesives include: low temperature and high temperature solder joint encapsulant adhesives, and their derivatives. Each solder joint encapsulant adhesive has: unfilled and filled solder joint encapsulant adhesives, and solder joint encapsulant paste. Each solder joint encapsulant product has been designed for different applications. In this paper, we are going to discuss the details and future of solder joint encapsulant adhesives.
Technical Library | 2016-01-12 11:04:35.0
3D packaging has recently become very attractive because it can provide more flexibility in device design and supply chain, reduce the gap between silicon die and organic substrate, help miniaturize devices and meet the demand of high speed, provide more memory, more function and low cost. With the advancement of 3D packaging, the bump height is now down from 80μ to 10μ. When the bump diameter is 20-40μ and height 10μ, the process and reliability are obvious issues. It is well known that underfill can enhance the reliability for regular flip chip, however underfill won’t help assembly process. In order to resolve some difficulties that 3D packaging faces, YINCAE Advanced Materials, LLC has developed solderable anisotropic conductive adhesives for 3D package applications. In this paper we will discuss the assembly process and reliability in detail.
Technical Library | 1999-07-21 08:49:49.0
As the role of direct-chip-attachment increases in the electronics industry, the reliability and performance of COB packaging materials becomes an increasing concern. Although many factors influence component reliability, the biggest determinants of performance are often the glass transition temperature (Tg) and the coefficient of thermal expansion (CTE) of the encapsulant or underfill. This paper discusses exactly what these properties are, how they are measured, and why they are important to device-reliability.
.gif)
.png)
