Thermal electronic materials

S. Sivaram, Principles of Chemical Vapor Deposition Thermal Plasma Deposition of Electronic Materials, Van Nostrand Reinhold, New York, 1995. 

Processing variables that affect the properties of the thermal CVD material include the precursor vapors being used, substrate temperature, precursor vapor temperature gradient above substrate, gas flow pattern and velocity, gas composition and pressure, vapor saturation above substrate, diffusion rate through the boundary layer, substrate material, and impurities in the gases. Eor PECVD, plasma uniformity, plasma properties such as ion and electron temperature and densities, and concurrent energetic particle bombardment during deposition are also important. 

The applications for addition polyimides are for electronic/electrical materials such as printed circuit boards and insulators, as matrix resins for structural composites in aircraft and as thermal insulation materials. Recently the market for polyimide based structural composites has suffered from the termination and reduction of military aircraft programs. However, the possible emergence of the High Speed Civil Transport program (HSCT) may offer an opportunity for addition polyimides (2). 

Fluorocarbons and fluoropolymers have been in commercial use for over half a century and have found their way into a diverse array of products. The members of this array are too numerous to hst but they include nonstick coatings for cookware, construction materials, carpets, textiles, paints, electronic materials, household cleaners and personal hygiene products. As fluorocarbons are expensive compared to their hydrocarbon analogues, they are chosen carefully and usually to fill a void in a product attribute that simply cannot be accommodated by another material. The attributes typically afforded by the use of fluorocarbons are repellency, lubricity, chemical and thermal inertness, and low dielectric constant, in regards to which fluorocarbons are unique among their hydrocarbon counterparts. 

Stability for use in optical interconnects. In the near future, optoelectronic integrated circuits and optoelectronic multichip modules will be produced. Materials with high thermal stability will thus become very important in providing compatibility with conventional 1C fabrication processes and in ensuring device reliability. Polyimides have excellent thermal stability so they are often used as electronic materials. Furuya et al. introduced polyimide as an optical interconnect material for the first time. Reuter et al. have applied polyimides to optical interconnects and have evaluated the fluorinated polyimides prepared from 6FDA and three diamines, ODA (3), 2,2-bis(3-aminophenyl) hexafluoropropane (3,3 -6F) (4), and 4,4 -6F (2), as optical waveguide materials. 

The PMDA/TFDB has a rather low fluorine content of 23.0% however, its CTE is extremely low at -5 x 10" °C". This low-expansion fluorinated polyimide is unique and very useful as a low-thermal-expansion component in optical and electronic materials. 

The optical anisotropy observed in most carbon materials reflects the ordered stacking of graphite-like microcrystalline units that has been recognized to be essential in determining their properties. Pitch-based carbon fiber, electrode and metallurgical cokes, and carbons for nuclear reactors are characterized by their anisotropic texture since this structural factor is fundamentally related to their mechanical, thermal, electronic, and chemical properties (1-5) ... 

Gadolinium 64 Gd Electronic materials, high-temperature refractories, alloys, cryogenic refrigerant, thermal neutron absorber, superconductor, magnetic materials, bubble memory substrates... 

In the academic setting, inkjet resolution reported for printed organic electronic materials is approximately 20-25 Lxm for untreated substrates and 5 p,m for thermal laser printing. For conductive metallic features, features of 10 Lxm or less have been reported for untreated surfaces. These limits can be further reduced by pretreating the substrate, for example by creating hydrophobic/ hydrophilic dewetting patterns. 

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