Wafer fabrication

Résumé

Wafer fabrication is a procedure composed of many repeated sequential processes to produce complete electrical or photonic circuits on semiconductor wafers in semiconductor device fabrication process. Examples include production of radio frequency (RF) amplifiers, LEDs, optical computer components, and microprocessors for computers. Wafer fabrication is used to build components with the necessary electrical structures. The main process begins with electrical engineers designing the circuit and defining its functions, and specifying the signals, inputs/outputs and voltages needed. These electrical circuit specifications are entered into electrical circuit design software, such as SPICE, and then imported into circuit layout programs, which are similar to ones used for computer aided design. This is necessary for the layers to be defined for photomask production. The resolution of the circuits increases rapidly with each step in design, as the scale of the circuits at the start of the d

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https://en.wikipedia.org/wiki/Wafer_fabrication

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Publications associées (53)

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Cours associés (7)

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Séances de cours associées (8)

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In this work we demonstrate microfabricated thin alumina nanopore membranes as a platform for impedance sensing of DNA immobilization and hybridization. We develop a wafer-scale fabrication of free-standing alumina nanopore membranes with well controlled thickness, pore diameter and overall pore density. One 1 cm x 1 cm single chip contains an array of 69 membranes. Each membrane is 100 mu m x 100 mu m large and 2 mu m thick, with pore diameter of 120 nm. With low pore density of similar to 6 pores/mu m(2), nanopore resistance and membrane capacitance can be recognized clearly in the electrochemical impedance spectrum from 100 to 1 MHz. The total surface area can be further increased by the coating of silica nanoparticles with similar to 20 nm in diameter. During the immobilization of probe ssDNA to (3-glycidoxypropyl) trimethoxysilane functionalized surface, the nanopore resistance drops significantly by 80%, whereas the membrane capacitance increases less than 2%. After hybridization with complementary DNA, the nanopore resistance increases up to 10%. Non-complementary ssDNA has no obvious effect. The detection limit is 12.5 nM in phosphate-buffered saline (PBS) solution. (C) 2015 Elsevier B.V. All rights reserved.

Elsevier Science Sa2015

Chargement

Continuous sampling and analysis by on-chip liquid/solid chromatography

Philippe Renaud, Mario Schlund, Silvan Schnydrig

This paper describes a lab-on-a-chip device for continuous liquid/solid chromatography measurements. Chromatographic separations of phenolic test solutions as well as of vitamins are illustrating the ability and versatility of the system. The dependence of the peak height and width with respect to the injected plug and the saturation limits of the microchip column have been investigated and good correlation to the theoretical predictions have been observed. The focus of the system design is on simplification of both fabrication complexity and application. To this end, large bore flow-through fluid introduction channels have been integrated onto the chip to allow aliquoting from meso-scale flows of sample (up to tenths of milliliters per minute). Repeatable plug injections and reproducible chromatographic separations were achieved in an open-tubular on-chip microcolumn with C8 stationary phase coating. The entire system allows for a rapid cycle time for multiple analyses, exchange of analyte and mobile phase in less than a minute, and complete cleaning cycles within a few seconds only. This makes it a suitable candidate for on-line process analysis applications

2007

Chargement

Wafer-Scale Fabrication of Thin SiN Membranes and Au Films and Membranes with Arrays of Sub-um Holes Using Nanosphere Lithography

Mona Julia Katharina Klein

In this thesis, the wafer-scale fabrication of SiN membranes, Au films and Au membranes with arrays of sub-µm holes is described. Two conceptually different processes (1) and (2) were developed, both of which are based on nanosphere lithography (NSL) with self-assembled close-packed monolayers of polystyrene (PS) beads. PS beads with a diameter D in the range of 420 nm to 530 nm were used. The hole array periodicity p was thus determined by D. Different bead deposition methods were tested; by spin-coating, a monolayer wafer coverage > 90% could be obtained. By O2-RIE, D could be reduced in a controlled way down to 0.3D. In process (1), holes were etched into the device layer using a hole etch mask made by NSL. The hole size ⌀ was determined by the reduced D. In this way, 100 nm thick SiN membranes with a maximum size of 2400×2400 µm2 and a hole density on the order of 108 holes/cm2 were fabricated by etching holes into the SiN. The membrane release was done in a combined dry-/wet-etch procedure. Similarly, hole arrays were fabricated on 2" glass wafers by sputter-etching into 200 nm thick Au films. With this process, different ⌀, e.g. from 60 nm to 180 nm, could be obtained for initially identical mask holes by tuning the sputter-etch parameters. In process (2), NSL was used to realize high aspect ratio Si and oxidized Si pillars that were subsequently used as a lift-off template. Free-standing, 200 nm thick, 1200◊1200 µm2 large Au membranes with ⌀ from 100 nm to 300 nm were successfully fabricated using Si pillars as KOH lift-off template and a Si-DRIE release procedure. Using oxidized Si pillars for lift-off in HF instead, such hole arrays in Au films could be transferred to flexible, transparent parylene films. The fabricated devices were characterized and successfully tested for stencil and refractive index sensing applications: Holey SiN membranes were bulge-tested and withstood pressures up to 5 bar, showing their suitability for stencil and filtration applications. Stenciling was successfully done for (a) the deposition of arrays of 230 nm in diameter Au and Ag dots onto Si substrates and (b) the etching of holes into a 500 nm thick SiN membrane. The light transmission characteristics of wafer-scale hole arrays in Au films were reproducible for different measurement locations. Similar hole arrays were used to detect refractive index changes in water of varying glycerine concentrations. The transmission through Cr/Au membranes with sub-wavelength hole arrays was measured. Upon Cr removal, the transmission was enhanced by a factor 2.4.

EPFL2010

Chargement

Wafer-Scale Fabrication of Thin SiN Membranes and Au Films and Membranes with Arrays of Sub-um Holes Using Nanosphere Lithography

Mona Julia Katharina Klein

EPFL2010