Technical Library | 2023-08-16 18:42:25.0
In one of our medical applications projects, the customer wanted to dispense a mask to protect gold leads and an underfill on a silicon substrate with a clear test die. The substrates were Dymax X-499-91-C for Masking and Epoxibond-106M-1 for Underfill Dispensing
Technical Library | 2024-08-20 00:40:08.0
In electronics manufacturing, 'Underfill' refers to a material that is applied to fill the gap between a semiconductor device, such as flip-chip assemblies, Ball Grid Arrays (BGA), or Chip Scale Packages (CSP), and the substrate, such as a PCB or flex circuit.
Technical Library | 2012-12-17 22:05:22.0
Package on Package (PoP) has become a relatively common component being used in mobile electronics as it allows for saving space in the board layout due to the 3D package layout. To insure device reliability through drop tests and thermal cycling as well as for protecting proprietary programming of the device either one or both interconnect layers are typically underfilled. When underfill is applied to a PoP, or any component for that matter, there is a requirement that the board layout is such that there is room for an underfill reservoir so that the underfill material does not come in contact with surrounding components. The preferred method to dispensing the underfill material is through a jetting process that minimizes the wet out area of the fluid reservoir compared to traditional needle dispensing. To further minimize the wet out area multiple passes are used so that the material required to underfill the component is not dispensed at once requiring a greater wet out area. Dispensing the underfill material in multiple passes is an effective way to reduce the wet out area and decrease the distance that surrounding components can be placed, however, this comes with a process compromise of additional processing time in the underfill dispenser. The purpose of this paper is to provide insight to the inverse relationship that exists between the wet out area of the underfill reservoir and the production time for the underfill process.
Technical Library | 2017-03-30 18:34:52.0
There are multiple methods, each with its associated benefits for given applications, for printing either solder paste or paste flux for BGA rework. Each of these methods is best-suited for a given situation, board layout and skill level of operators performing the BGA rework. This discussion will layout the various methods and present the specific circumstances for which the specific technique is most wellsuited. In addition, the pluses and minuses for each of the approaches will be discussed in detail.
Technical Library | 2014-04-11 16:03:15.0
In order to meet the increasing demand of device miniaturization, high speed, more memory, more function, low cost, and more flexibility in device design and manufacturing chain, underfilling has increasingly become an essential process for the good reliability of electronic devices. Filled capillary underfill has been selected for use in package-level where there is large thermal stress caused by CTE mismatch issue, but the underfill is usually not reworkable. Unfilled capillary underfill has been used for board-level application such as BGA/CSP, POP, WL-CSP where there is need for mechanical shock resistance, the underfill is usually reworkable.
Technical Library | 2016-01-12 11:09:47.0
In order to meet the increasing demand of device miniaturization, high speed, more memory, more function, low cost, and more flexibility in device design and manufacturing chain, underfilling has increasingly become an essential process for the good reliability of electronic devices. Filled capillary underfill has been selected for used in package-level where there is large thermal stress caused by CTE mismatch issue, but the underfill is usually not reworkable. Unfilled capillary underfill has been used for board-level application such as BGA/CSP, POP, WL-CSP where there is need for mechanical shock resistance, the underfill is usually reworkable.
Technical Library | 2017-08-17 12:23:27.0
A novel epoxy flux EF-A was developed with good compatibility with no-clean solder pastes, and imparts high reliability for BGA assembly at a low cost. This compatibility with solder pastes is achieved by a well-engineered miscibility between epoxy and no-clean solder paste flux systems, and is further assured with the introduction of a venting channel. The compatibility enables a single bonding step for BGAs or CSPs, which exhibit high thermal warpage, to form a high-reliability assembly. Requirements in drop test, thermal cycling test (TCT), and SIR are all met by this epoxy flux, EF-A. The high viscosity stability at ambient temperature is another critical element in building a robust and userfriendly epoxy flux system. EF-A can be deposited with dipping, dispensing, and jetting. Its 75°C Tg facilitates good reworkability and minimizes the adverse impact of unfilled underfill material on TCT of BGA assemblies.
Technical Library | 2020-02-18 09:56:24.0
Glob Top, Dam and Fill & Flit Chip Underfill To protect PCBs from damaging outside influences, they are coated with a thin layer of casting resin or protective finish during the conformal coating process. In addition to sealing the entire circuit board, it is possible to pot only sections or individual components on the substrate. Different methods ranging from "glob top" to "dam and fill" and "flip chip underfill" have been developed for this purpose.
Technical Library | 2008-11-06 02:17:59.0
For many years Acoustic Micro Imaging (AMI) techniques have been utilized to evaluate the quality of the underfill used to support the solder bump interconnections of Flip Chip type devices. AMI has been established as one of the few techniques that can provide reliability and quality control data, but little has been done to automate the evaluation process for Flip Chip underfill until now.
Technical Library | 2021-12-16 01:45:05.0
In the 1990's, both BGA (Ball Grid Array) and CSP (Chip Size Package) are entering their end in the front-end packaging materials and process technology. Both BGA and CSP like SMD (Surface Mount Device) from the I 980's and THD (Through-Hole mount Device) from the 1970's are reaching its own impasse in terms of maximizing its electrical, mechanical, and thermal performances, size, weight, and reliability.
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