The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Thermosetting polymers are widely used in electronic industry as encapsulants of electronic devices. It is well known that properties of polymers and polymer-based composites like molding compounds are highly dependent on conditions like: temperature, time, humidity, degree of cure etc. These effects are investigated extensively in the past. Surprisingly, the effect of postcure and thermal aging on...
An ongoing root cause of failure in microelectronic industry is interface delamination. In order to explore the risk of interface damage, FE simulations for the fabrication steps as well as for the testing conditions are generally made in the design stage. In order to be able to judge the risk for interface fracture, the critical fracture properties of the interfaces being applied should be available,...
Warpage is a critical issue for an electronic package molding process. Much work is done in the past to predict the warpage of a package after the cooling down from the molding process. However, there are many material models for the molding compound to predict warpage: Elastic and viscoelastic models are used, and there are even groups which use cure-dependent viscoelastic models. In this paper,...
Warpage is a critical issue for a QFN panel molding process. Much work is done in the past to predict the warpage of a package during cooling down from molding temperature. However, until now, warpage could not always be predicted well, even if the viscoelastic behavior of the molding compound is taken into account. It was for example observed that the cooling velocity affected the warpage after cooling...
Generally, the viscoelastic properties of packaging materials used in the simulation models are obtained from the materials after postcuring. However these properties were observed to change during humidity conditioning and the thermal cycling. Two kinds of packaging materials are tested, one is molding compound and another is underfill. All samples are cured according to the curing procedure, postcured...
Reliability calculations of the microelectronic packages require cure dependent viscoelastic constitutive relationship for the packaging polymers in order to predict residual stress and strain fields in the final product. The residual stresses can result in the product failure due to warpage, interfacial delamination, thermal fatigue etc. The previous work in the same group (Ernst et al. 2006, 2003)...
Packaging failures has always been the bottleneck of the development on the new techniques of IC packaging using molding compounds. Numerous simulations are developed to minimize the maximum stress during or after the packaging process. Within those simulations, a reliable kinetic model is indispensable since the viscoelastic properties are related strongly with conversion during the cure process...
In previous work a cure, temperature and time (history) dependent model was developed for the thermal mechanical description of viscoelastic behaviour of moulding compounds during cure. However, so far experimental characterization of the model parameters was restricted to slowly curing compounds that had to be fabricated on laboratory scale. Commercially available moulding compounds generally cure...
One type of polymer EPN1180 is selected for the hygroscopic swelling tests and the sample is made in the thickness of 30mum . Coefficient of thermal expansion is tested by using DMA Q800 and coefficient of moisture expansion is tested by using DMA Q800 jointed with a humidity generator. Three conditions temperature, 50degC, 60degC, and 70degC, and different relative humidity with 20RH% steps are used...
Four types of polymer which were selected are EPN1180 and EPN1180 filled with, 40%, 50%, and 65% fused silica. The moisture absorption is carried out in an adjustable thermal and humidity chamber at different temperature and humidity. The diffusion coefficients at different conditions were obtained through the early stage moisture absorption tests. The moisture absorption was revealed to show the...
Package warpage, interface delamination and thermal fatigue are the major reliability concerns for micro-electronic packages, caused by mismatch in thermal expansion together with residual stress originating from the curing process of the packaging polymers. To investigate the influence of the residual stress- and strain fields on the failure predictions and to optimise the product for reliability,...
The ongoing miniaturization of microelectronics has led to low-K polymer dielectric films with a thickness of several tens of nanometers. These thin polymer films generally show time dependent material properties, that are different in lateral directions and in-thickness direction. Most techniques available for measuring the mechanical properties of thin films are only capable of obtaining the in-plane...
The present state-of-the-art in simulation of stresses in electronic packages is to model the moulding compound as a viscoelastic material. That means that stresses during packaging and subsequent thermomechanical loading are allowed to relax partially. Such an approach was seen to improve thermomechanical predictions considerably compared to the previously used temperature dependent elastic models...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.