Realization of mechanical decoupling zones for package-stress reduction

The realization of mechanical decoupling zones around a membrane to reduce package stresses is presented. Wet-isotropic etching with a nitric/fluoridic solution (HNO3/HF/H2O) as well as reactive-ion etching (RIE) with a sulphurhexafluoride/oxygen (SF6/O2) plasma are investigated to realize deep circular grooves. The shape of the cross section of the groove, which determines the shape of the decoupling zone, can be controlled using the RIE method by changing the etch conditions. It is shown that a large undercut at low pressures as well as a small undercut at high pressures is possible with a SF6/O2 plasma, leading to round or steep sidewalls of the grooves, respectively. Finally a completed bare structure containing a membrane and a surrounding decoupling zone is presented

Resonating silicon beam force sensor

A resonating silicon-beam force sensor is being deveoped using micro-machining of silicon and IC-compatible processes. Results are reported here of measurements on the force-to-frequency transfer of bare silicon prototypes. The measurements with forces on the sensor beam up to 0.4 N shows a frequency shift of 3.1 to 5.2 times the unloaded resonance frequency f0(f0 congruent with 3 to 5 kHz), depending on the exact dimensions. Considering these figures, we can predict a frequency shift of 18.3 to 27.6 kHz at the maximum load of 1.0 N for the measured samples. Due to the sample lay-out, a force transfer is present from the externally applied force to the actual pulling force on the sensor beam. Using a simple model to calculate this reduction, we obtain good agreement between the measurements and predictions

Fundamental study on a thin-film ae sensor for measurement of behavior of a multi-pad contact slider

To study the fundamental dynamic characteristics of a multi-pad slider for contact recording, we developed a thin-film piezoelectric acoustic emission array sensor on an Si-suspension with an array pattern similar to that of contact pads. Experiments showed that the sensitivity of the sensor is about 0. 11 V/N (slider thickness: 0.2 mm) and that each array sensor designed here is not influenced by the acoustic waves which occur due to contact with other contact pads, so the contact or non-contact condition of each pad can be measured

Thin-film piezoelectric impact sensor array fabricated on a Si slider for measuring head-disk interaction

A new type of Acoustic Emission sensor using a thin film piezoelectric material (sputtered ZnO) was developed for measuring head-disk interaction in a rigid magnetic disk system. The sensor is mounted on a Si slider (length: 3 mm) and was fabricated using micro-machining techniques in our on-going efforts to downsize sliders. Some fundamental tests of the sensor were conducted: sensitivity and frequency characteristics, and a flying test over a rotating bump disk

Piezoelectric impact force sensor array for tribological research on rigid disk storage media

This paper presents a method to measure impact forces on a surface by means of a piezoelectric thin film sensor array. The output signals of the sensor array provide information about the position, magnitude and wave form of the impact force. The sensor array may be used for tribological studies to the slider disk interface of a rigid disk storage device. In such a device a slider head assembly is flying above the rotating disk with a typical spacing of 100nm. Possible mechanical interactions between the slider and the disk are expected to produce impact forces in the order of 0.1N with a frequency range from 100kHz to 100MHz [1]

Performance of thermally excited resonators

A study of electrothermal excitation of micromachined silicon beams is reported. The temperature distribution is calculated as a function of the position of the transducer, resulting in stress in the structure which reduces the resonance frequency. Test samples are realized and measurements of resonance frequency, vibration shape and vibration amplitude are carried out. There is a satisfactory agreement between theory and experiment at small thermal stresses. Near the buckling load we find distinct deviations from theory which are ascribed to mechanical imperfections of the beams

Excitation and detection of vibrations of micromechanical structures using a dielectric thin film

A new technique is introduced for both the excitation and the detection of vibrations of micromechanical structures. This makes use of a dielectric thin film, sandwiched between lower and upper electrodes, on top of the vibrating structure. The excitation is based on electrostatic forces between the charged electrodes, causing deformation of the dielectric film and bending of the multilayer structure. The detection of the vibration is capacitive, based on the fluctuation of the capacitance due to the deformation of the dielectric film. Experimental results for a stoichiometric silicon nitride dielectric film on top of a silicon cantilever agree well with predicted values. The yield of the electrostatic excitation as well as of the capacitive detection are satisfactory

High resolution shadow mask patterning in deep holes and its application to an electrical wafer feed-through

The paper presents a technique to pattern materials in deep holes and/or on non-planar substrate surfaces. A rather old technique, namely, electron-beam evaporation of metals through a shadow mask, is used. The realization of high-resolution shadow masks using micromachining techniques is described. Further, a low ohmic electrical wafer foed-through with a small parasitic capacitance to the substrate and a high placing density is presented

Liraglutide and sitagliptin have no effect on intestinal microbiota composition : A 12-week randomized placebo-controlled trial in adults with type 2 diabetes

Aim: Preclinical data suggest that treatment with either glucagon-like peptide (GLP)-1 receptor agonists or dipeptidyl peptidase (DPP)-4 inhibitors could change the intestinal microbiome and thereby contribute to their beneficial (cardio)metabolic effects. Therefore, our study aimed to investigate the effects of these agents on microbiota composition in adults with type 2 diabetes (T2D). Methods: A total of 51 adults with T2D (mean +/- SD: age 62.8 +/- 6.9 years, BMI 31.8 +/- 4.1 kg/m(2), HbA(1c) 7.3 +/- 0.6%) treated with metformin and/or sulphonylureas were included in the 12-week randomized, double-blind trial. Patients were given the GLP-1 receptor agonist liraglutide (1.8 mg sc) or the DPP-4 inhibitor sitagliptin (100 mg), or matching placebos, once daily for 12 weeks. Faecal samples were collected at baseline and at 12 weeks after the start of the intervention. Microbiota analyses were performed by 16S rRNA gene-sequencing analysis. Bile acids were measured in faeces and plasma. Results: Liraglutide decreased HbA(1c) by 1.3% (95% CI: -1.7 to -0.9) and tended to reduce body weight (-1.7 kg, 95% CI: -3.6 to 0.3), but increased faecal secondary bile acid deoxycholic acid. Sitagliptin lowered HbA(1c) by 0.8% (95% CI: -1.4 to -0.4) while body weight remained stable (-0.8 kg, 95% CI: -2.7 to 1.0), but increased faecal levels of cholic acid, chenodeoxycholic acid and ursodeoxycholic acid. However, neither liraglutide nor sitagliptin affected either alpha or beta diversity of the intestinal microbiota, nor were changes in microbial composition related to clinical parameters. Conclusion: These data suggest that the beneficial effects of liraglutide and sitagliptin on glucose metabolism, body weight and bile acids, when used as add-on therapies to metformin or sulphonylureas, are not linked to changes in the intestinal microbiota (NCT01744236). (C) 2021 The Authors. Published by Elsevier Masson SAS.Peer reviewe