Adhesion test for UTCP structure in humid environment

Ultra-Thin Chip Packaging (UTCP) technology enables the integration of off-the-shelf integrated circuits into thin substrates such as different kinds of circuit boards. This technology has been created at CMST during many years of intensive study. In this technology the thinned chip is embedded into polyimide and a copper fan-out is created to form the connections between the chip and the circuit board. This technology is compatible with standard circuit board manufacturing technology, which makes it an attractive solution to create miniaturized packages for electronics. In this paper the reliability of UTCP structure was studied using adhesion peel testing. The different solutions for constructing the material layers inside a UTCP were compared for their adhesion. Special test structures were manufactured for testing. The tested material layers consisted of polyimide, benzocyclobutene (BCB) and adhesion promoter for BCB. Altogether four different constructions were tested and the peel testing was done to half of the samples right after manufacturing and to the other half after exposure in 85/85 –environment for 500h. The results show difference in adhesion after exposure to humidity. Test structures with BCB suffer from loss of adhesion in PI – BCB interface after exposure to moisture. This result addresses that the structure is more reliable when the amount of different materials and interfaces is decreased

Parylene C for hermetic and flexible encapsulation of interconnects and electronic components

Flexible electronics are of a great interest for wearable and implantable medical devices due to their conformality with the body, compared to electronics made on rigid carriers. Packaging of such electronics needs to offer sufficient flexibility and in addition, has to provide good protection for the electronics inside, also in humid and harsh environments, to prevent device failure due to corrosion. Parylene C is a popular polymer due to its interesting diffusion barrier properties. Parylene C coatings are also extremely conformal, hence it offers the possibility to be used as flexibleprotecting encapsulation for electronic components and interconnects. In order to provide sufficient mechanical support for the electronic circuit, a second encapsulation in PDMS will be performed. In our work, we study the barrier properties of Parylene for long time exposure to moisture and biofluids. Since adhesion is a very important parameter to prevent corrosion, this property is studied in detail. Various substrates and various adhesion promotion treatments are evaluated. Furthermore, copper interconnects coated with parylene C are immersed in biofluids at 37 C to study corrosion. Accelerated testing is also performed at 70 C to mimic long time exposure in a harsh, humid environment. Since the Parylene barrier layers are typically 5-15 micron thick, they are highly flexible, and hence they are interesting barriers to be used in flexible/stretchable electronics. Therefore, special attention is given to the evaluation of barrier properties when Parylene is bended and stretched

High-yield embedding of 30µm thin chips in a flexible PCB using a photopatternable polyimide based ultra-thin chip package (UTCP)

Thinning down ICs is a well-known approach to reduce the volume of chip packages. In this work ICs are thinned down to 30um, followed by a package procedure in polyimide with copper fan out, which allows their embedding in adhesives used for laminating flexible printed circuit boards (PCBs). In this way the chip does not consume PCB area, hence other circuit components can be assembled on top or at the bottom of the chip, enabling extreme circuit miniaturization. Furthermore, our ultra-thin chip package (UTCP) is highly flexible, enabling flexible electronic circuits without large rigid chip packages. Spin-on photo-definable polyimide precursors are used to build an interposer which can be embedded later in the flexible PCB. The chip is fixed in between three polyimide layers using BCB as adhesive. The central polyimide layer forms a cavity for the chip, the top layer of polyimide is exposed and developed to fabricate vias contacting the chip. An 8um thick copper layer is deposited and patterned using lithography and etching to form the fan-out, essential to match the fine IC pitch to the larger PCB pitch. The final chip package is about 75um thick, and is easily embedded using only small adaptations of the standard flexible PCB fabrication process. Last year, both the UTCP concept and the embedding in a flexible PCB were optimized in order to obtain a very high yield. Three types of chips were UTCP-packaged and embedded in a flexible PCB: two types of microcontrollers (MSP430F1611 and a proprietary digital signal processor) and an RF-chip. The yield of the tested UTCPs ranges in between 65% (proprietary IC) and 85% (MSP430F1611). The performance of the RF-chips can only be tested after embedding in a flexible substrate. Although the testing is still ongoing, 95% of the embedded UTCPs are fully functional after embedding

Embedding thinned chips in flexible PCBs

Autonomous systems for healthcare and sports applications benefit largely from a small form factor, as minute dimensions result in maximal mobility and comfort. By embedding a commercially available IC in a flexible circuit board (FCB), the overall size of a system can be reduced. This work presents the process of thinning and packaging an IC in a flexible interposer, and the embedding thereof in a FCB. To illustrate the potential of this technology towards miniaturization, a commercially available RF transceiver ZL70102 was packaged and embedded, thus realizing a volume reduction of 60%

Work participation and work transition in patients with systemic sclerosis: a cross-sectional study

Objectives. To describe work participation and work transition due to health in patients with SSc. Associations are assessed between having made a work transition or not and factors possibly influencing that transition. Methods. This study included patients visiting the Scleroderma Clinic of the Ghent University Hospital, who regularly undergo an extensive evaluation. For this study, a questionnaire was used to collect work participation and work transition data. Results. Eighty-four patients in the adult working-age population were included. Thirty-eight (45%) out of 84 patients participated in the labour force. Forty-six (55%) out of 84 were not engaged in a paid job; in 34 (74%) out of 46 patients this was attributed to health issues. Seventy-six (90%) out of 84 patients made a work transition. Forty-seven (62%) out of 76 made that transition due to health reasons. The group that made a health-related work transition (47/84, 56%) was compared with the remaining group (37/84, 44%) that made no work transition or a work transition for reasons other than health. There was a significant difference in educational level, skin score, lung disease severity, disease activity, disease duration, scleroderma Health Assessment Questionnaire (sHAQ), visual analogue scale (VAS) for RP, VAS for intestinal disease, VAS for overall disease, VAS for pain, Medical Outcomes Study short form 36 (SF-36), work statute and willingness to participate in training. The multivariate analysis retained sHAQ, SF-36 and disease duration as associating variables. Conclusions. Work participation is limited in patients with SSc and a majority make a work transition because of health problems. Demographic, disease- and work-related variables, as well as willingness to participate in training are associated with (the occurrence of) work transition

Latent personality profiles and the relations with psychopathology and psychopathic traits in detained adolescents

The present study constructed empirically derived subtypes of adolescent offenders based on general traits and examined their associations with psychopathology and psychopathic traits. The sample included 342 detained minors (172 boys and 170 girls; mean age 15.85 years, SD = 1.07) recruited in various Youth Detention Centers across the Flemish part of Belgium. All adolescents provided self-reports on the quick big five, the youth self report, and the youth psychopathic traits inventory to assess general traits, psychopathology, and psychopathic traits respectively. Latent class analyses based on general personality traits were performed and suggested three personality types, consisting of an emotionally labile, close-minded and goal-oriented class, an undercontrolled class, and an emotionally labile-careless class. These three personality types within detained minors showed particular constellations of general traits and differed meaningfully in terms of their mean-scores on externalizing psychopathology and psychopathy measures

Functionality of vegetable proteins in gluten-free dough and bread

Recently, there has been an increasing demand for high quality gluten-free breads wherein the application of proteins is a possible strategy. This research focused on the characteristics (moisture, ash, protein content, particle size distribution, water holding capacity (WHC) and solubility, oil binding capacity, gel forming and mulsifying capacity) of four alternative, non-allergen roteins (corn, pea, potato, rice) and their functionality (WHC, starch gelatinisation, frequency sweep, creep recovery, texture profile analysis) in three gluten free dough and bread systems (rice flour, wheat starch or corn/potato starch (1:3) with 14% protein substitution). Incorporation of proteins led to an increase in dough consistency, depending on the matrix and the nature of the protein. Pea protein increased the consistency of the dough based on the corn/potato starch blend or wheat starch. Corn or rice protein only increased dough consistency in the corn/potato starch system. The selected proteins had no elasticity promoting effect on gluten-free doughs. All proteins had a hardening effect on the corn/potato starch breads, while they had no effect on the hardness of rice flour system breads. In the wheat starch bread, pea and rice protein led to an increase in crumb hardness, while potato and corn starch significantly increased hardness. Proteins cause better crumb structure but have no volume increasing effect. In conclusion, the influence of proteins to gluten free dough and bread is clearly depending on the nature of the chosen starch/flour matrix and the protein. Optimal amounts of water and the addition of transglutaminase should lead to better results

Over-representation of construction-related occupations in male patients with systemic sclerosis

Aims: Based on preliminary observations, we tested the hypothesis that construction-related occupations are associated with systemic sclerosis (SSc). Methods: The professional occupation of 91 patients with SSc (71 females and 20 males) was recorded. Categorisation into construction-related and other professions was performed. A double definition was used for construction-related occupations. The first (limited) definition was based upon categories of the Belgian National Institute of Statistics (NIS) occupational list. The following occupations were considered construction-related: electricians, joiners, masons and tilers, plumbers and pipefitters. The use of this list also allows us to compare the distribution of professions in these patients with that in the general population. As the NIS occupational list is limitative and leaves out some "real-life" construction-related occupations, a second and broader interpretation was given to the concept of construction-related occupations. Results: The prevalence of construction-related professions in males with SSc, according to the limited definition, was 10-fold higher than in the general working population (50% vs 5%; p<0.001). Interestingly, most of the patients with construction-related occupations were electricians. In the broader interpretation, 75% of the men with SSc fell into the category of construction-related occupations. Conclusions: The data show an association between SSc and professional occupation