Conductor tracks

In a second embodiment the strip detectors A to H are mounted on an intrinsic p-type silicon substrate 3A covered by a silicon oxide layer 3B. A patterned arrangement of conductor tracks 21 is formed in the semiconductor base 3B. Each track is formed by diffusion or ion-implantation of an n-type dopant material, and isolated from adjacent tracks by means of a channel stop network 23. Bridging links of nichrome-gold are formed to define and connect the read-out regions to the tracks 21. The links 25 are paired and thus provide voltage detection contacts. The tracks 21 are connected to connection pads 29. Signal processing circuitry is incorporated in the semiconductor base layer 3B. 

Figure 1. Microcircuit used for corrosion monitoring. Contains three interdigitated pairs of conductor tracks.

Every production process that applies high mechanical stress to the sensor could result in a change of zero-offset Hence the calibration of the sensor should be done as late as possible to have a chance to compensate those influences. The sensor shown in Fig. 7.4.7 is calibrated when completely mounted by using one of the connector terminals for communication with the ASIC. Doing this enables one to compensate for production influences and to prevent additional conductor tracks and their potential influence on electromagnetic resistance of the sensor. 

In Equation [7.7], is the Seebeck coefficient of the gas sensitive film, AVgst is the measured thermovoltage of the gas sensitive film, and AT is the temperature difference at the junctions between the gas sensitive layer and the conductor tracks. Due to the fact that the conductor tracks also add a thermovoltage, the thermopower of the gas sensitive layer has to be corrected by the thermopower of the conductor track material (here, platinum), J7p,. 

There are two ways to determine the temperature difference between the junctions of the conductor tracks and the gas sensitive film. Rgure 7.1 depicts both possibilities in (b), the temperature difference, AT, is directly determined, whereas in (c),the temperatures at both junctions, T and T2,are measured separately and the temperature difference AT is calculated. Due to the fact that not only the temperature difference, but also the temperature of the... 

A sensor was fabricated according to the design illustrated in Fig. 7.2. First, the platinum modulation heater was screen-printed and fired then, the insulation layer was applied onto the modulation heater layer. After the equipo-tential layer and a further insulation layer, the heater and its conductor tracks were applied. Finally, the thermocouples were screen-printed on the top and... 

Pt-conductor tracks SrTiosFeo.Og layer Au-conductor tracks SrAlgO layer Substrate Aip Equipotential layer Au... 

Various copolymers with the basic backbone of —Ar—NH—Ar—S—, i.e., aromatic amino sulfide copolymers have been synthesized. This type of copolymer is semiconducting and can be used in many electronic and electro-optical applications. Examples of such applications are antistatic layers, electromagnetic-shielding layers, anticorrosion layers, batteries, electroluminescent devices, and in electronic circuits, such as conductor tracks of transistors. 

LED lamp with injection moulded conductor tracks... 

The cable test piece consists of ten untwisted strands of btu e copper wire moimted on a glass fiber-filled epoxy substrate with holes to allow flux residues to pass from the underside of the board to contaminate the cables on the topside during wave soldering. A DC power supply poleuizes the test pieces anodically with respect to the copper conductor track on the laminate. 

Fully electroless copper deposition on the conductor tracks and hole walls... 

Anisotropically conductive adhesives conduct in one direction only. They are often referred to as z-axis conductive adhesives. These materials have found widespread use in LCD, Liquid crystal display, assembly due to their ability to resolve small gaps between conductor tracks and the fact that solder is not suitable for joining on glass substrates. 

The corrosion test is designed to measure the rate of corrosion of a very thin copper wire. It is critical that the copper wire be thin because the test depends upon the difference in resistance of the wire over time. Therefore, no solder is used in preparing the test coupons—only flux, solder paste flux, or cored-wire flux should be applied to the copper anode and heated to soldering temperatures. This test provides complementary information to the SIR test that measures the insulating characteristics of the laminate. SIR readings, however, reflect the combined effect of (a) residues that are corrosive to the conductor tracks and (b) residues that interact with the laminate. 

A paper by Hampel proposes a specification including the peel strength, the electrical resistance of the conductor tracks, and a series of environmental tests... 

In version 1 of the PCK process (Fig. 2.14, left) a metallizable, electrically noncon-ductive plastic is used for the first shot, and molding produces a raised structure corresponding to the subsequent conductors of the MID. The second shot then covers the areas between the conductor tracks with a nonmetallizable plastic. 

Conductor track width Conductor track spacing 0.25 0.6 0.4 0.6 0.5... 

Conductor tracks in the 150 pm range present no difficulty. Even smaller structures are possible with suitable stencils, resists, and base materials, and the same applies to vertical interconnects. The only drawback is that the two-part photomasks impose constraints regarding three-dimensionality, for example because conductor geometry cannot be overly complex [48]. 

The focused aerosol particles are 1 to 5 pm in size and permit microfine conductor structures down to widths of 10 pm and 20 pm spacing. Ink, substrate, and print parameters all have to be closely matched in order to achieve structures as fine as this. On account of the parallel alignment and high exit speed of the aerosol, the contour sharpness of the conductor track geometry remains virtually constant even when the nozzle-to-substrate gap is as wide as 3 mm. Consequently, small irregularities in the substrate surface are easy to print without modification of the print head s z-axis alignment. 

Ideally, MID components are produced in medium-to high-voiume runs with singie-layer conductor tracks on planar surfaces. Inclined planes can be embossed, subject to certain restrictions, but it is virtually impossible to emboss cavities. All in all, the requirements that apply to the embossing tool are high. The conductor pattern to be embossed should measure <100 cm and the length-to-width ratio has to be less than 4 1. 

The conductor layout has to be designed to avoid possible problems. For example, transitions should always be rounded and neither conductors nor pads should have sharp corners or right angles. Conductor tracks should not taper. Thermo-mechanical stresses and strains can cause cracking, which would damage the film. This can be avoided by rounding the features of the circuit layout. Excess film should be easy to remove after embossing, so the structures should not form enclosures around excess film. 

A method known as the transfer decal process can be used to transfer the conductor layout from a film to a plastic body. The conductor side of the film is backfilled and then the film is peeled off the finished MID component. This process requires low adhesion between backing film and backfill material. A low-strength bond between conductor tracks and backing film is also essential. The conductor tracks can be surface-treated to ensure good adhesion to the backfill material [48]. 

These properties cards are helpful for selecting the best-fit process for the MID basic solution. Direct correlations can be set up between the requirements features of the basic solution and the properties features of the production processes. This is the case, for example with conductor tracking as a requirement feature and 3D design freedom of the conductors as a property feature. Requirements profiles for specific MID can be matched directly to property profiles of particular manufacturing processes in this way. 

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