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Jet Process |
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Specialists in Gold Tin Solder and Other Coatings & Other Advanced Thin Films |
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Microelectronics . Semiconductor Packaging . Optoelectronics & Photonics . Solid State Lighting . |
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Jet Vapor Deposition™ (JVD™) Processes JVD is a proprietary, innovative, enabling, low cost, high throughput thin film coating technology. The patented JVD process uses sonic jet nozzles, operating in chambers at ambient temperature (<100° C) and low vacuum (1-5 Torr), to deposit dense, adherent, high quality films at rates far higher than competitive techniques. JVD equipment and processes are straightforward, robust, modular, environmentally safe, inherently low temperature, and offer incomparable process flexibility.
How JVD Works The JVD sonic jet is formed by a fast flow of high purity inert gas, such as argon or helium, through a nozzle in a chamber at ambient temperature and low (1 Torr) vacuum. Sonic flows are sustained by a high speed mechanical pump. Gas flow rates, nozzle sizes and pumping speeds are controlled to achieve an “upstream-downstream” pressure ratio exceeding 2, which creates sonic flows. A wide variety of vapor sources, typically using solid metal precursors in wire or rod form, are used to create atoms and molecules of metals or other materials, which are entrained in the sonic jet gas flow and carried through the nozzle to the substrate. A range of proprietary vaporization schemes are used to create high materials throughput and high deposition rates, e.g., ten microns of metals such as Au, Sn, Cu, Cr, Ag and alloys such as Au/Sn in about 30 minutes on a 4" wafer. Although the collimated vapor flux in the jet produces a narrow deposition profile, a variety of proprietary relative motion schemes are used to obtain coating surface uniformity. These proprietary JVD scanning techniques include either substrate or jet source motion, using computer controlled algorithms, resulting in excellent surface uniformity. JVD metal and dielectric films ranging in thickness from <100Å to several microns, deposited on 8" wafers, show measured surface uniformities of ±2% (3 sigma) or better. High purity carrier gases (impurities <1 ppm) and JVD’s unique fast flow conditions assure film purity. Data on JVD metal and dielectric films developed and tested for advanced CMOS applications show very low contamination and particle levels and are consistent with industry requirements. Alloy composition is accurately maintained by many methods such as the steady state vaporization of AuSn alloy wire fed to a hot filament under computer control. Extensive customer qualification of JVD thin film (1-20 micron) AuSn solders shows excellent adhesion, high shear strength, low stress, exact stoichometry including the 80/20 eutectic or other alloy composition, reliable “wetting”, etc. In JVD metal deposition, substrate surface temperature is typically well below 100°C, enabling use of glass, polymer or other heat sensitive substrates. Varied substrate heating schemes are available if needed. In addition, JVD’s low temperature, low vacuum operating conditions are compatible with virtually all mask or pattern materials, photoresists, etc., including use with materials which outgas. Our proprietary JVD “e-jet” sources, used for most metallizing applications, produce very high plasma densities, measured at >1015 ions/cc, downstream of the jet nozzle. In addition to providing very high vaporization rates, the e-jet enables “gentle” ion bombardment at low energy and high current to improve film density and relieve stress. For example, we used the e-jet to deposit a Ti ribbon of 35 microns thick, 1” wide and 3’ long at near bulk density. JVD produces metal films with near bulk electrical resistivity, e.g., Cu measured at <1.90 ohm-cms. In addition to high ion density, the e-jet can generate high densities of O and H atoms for in-situ “plasma clean” removal of substrate contaminants and native oxides, thus improving film adhesion. Stud pull tests of JVD metal films such as Cu, Au/Sn, Ti/Pt/Au, TaN/Cu deposited on silicon or ceramic substrates such as Al2O3 and AlN, have shown bond strength as high as 10,000 PSI. In addition, customer measurements of JVD 80/20 gold-tin thin films (~4 microns) confirm low residual tensile stress levels of 51 MPa. JVD also provides conformal coverage on submicron wafer geometries. JVD offers single step processing of multiple layers and alloys and permits reactive deposition, downstream of the nozzles, of oxides and nitrides, providing outstanding and enabling process versatility. This makes JVD useful for many applications, such as piezoelectric sensors and integrated MEMS fabrication. JVD is also a clean, dry, pollution free technology. We use safe inert gases and no toxic precursors. JVD produces no toxic process effluents and its very high materials conversion rates (often >90%) result in minimal process waste. Due to the absence of chemical precursors, excess precious metal, e.g. gold or gold-tin solder material, is easily recovered in reusable form. JVD’s high rates, very efficient materials usage, control of exact alloy composition and production of near bulk materials properties, all at low temperature, provide UNIQUE PROCESS ADVANTAGES for gold-tin solder or lower temperature lead free solders, dielectric compounds and many other advanced applications. In sum, JVD combines unequaled process flexibility and advantages, compatability with standard semiconductor processing, complete safety and environmental friendliness and user friendly, low cost operations. Numerous papers published in technical journals by Jet Process and various collaborators provide extensive information and data on JVD processes and films. Copies are available on request JVD™ Films & Processes
JVD Process Metal Deposition Rates Many JVD™ sources have a high metal vapor throughput. For example, for metals such as Au, Sn, Cu, Cr, Ag, Al or Au/Sn solder alloys, we uniformly deposit 1 micron of material on a 4” wafer in about 3 minutes. Jet diameters are typically ~1/2", so deposition is localized. We uniformly coat larger areas, multiple small substrates, or continuous strips by means of many different computer controlled jet-substrate relative motion schemes. Laboratory data reported by SEMATECH and other leading semiconductor device manufacturers confirms measured surface uniformity on 8” wafers of ±2% (3 sigma). Batch Processing of Au/Sn Solder Alloy
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Jet Process Corporation |
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