Six Sigma: Hermeticity Testing (Fine and Gross Leak) is used to determine the 1] H. Greenhouse, Hermeticity of Electronic Packages (William Andrew. As early as the s, SCHOTT’s Business Unit Electronic Packaging .. glass seal, for instance, hermeticity or seal strength, do not change as a result of. Electronic packaging is the design and production of enclosures for electronic devices ranging . Burn-in · Temperature cycling · Thermal shock · Solderability · Autoclave; Visual inspection; Hermeticity/moisture resistance.
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Electronic packaging is the design and production of enclosures for electronic devices ranging from individual semiconductor devices up to complete systems such as a mainframe computer. Packaging of an electronic system must consider protection from mechanical damage, cooling, radio frequency noise emission and electrostatic discharge. Product safety standards may dictate particular features of a consumer product, for example, external case temperature or grounding of exposed metal parts.
Prototypes and industrial equipment made in small quantities may use standardized commercially available enclosures such as card cages or prefabricated boxes. Mass-market consumer devices may have highly specialized packaging to increase consumer appeal. Electronic packaging is a major discipline within the field of mechanical engineering. The same electronic system may be packaged as a portable device or adapted for fixed mounting in an instrument rack or permanent installation.
Packaging for aerospace, marine, or military systems imposes different types padkages design criteria. Electronic packaging relies on mechanical engineering principles such as dynamics, stress analysis, heat transfer and fluid mechanics.
High-reliability equipment often must survive drop tests, loose cargo vibration, secured cargo vibration, extreme temperatures, humidity, water immersion or spray, rain, sunlight UV, IR pf visible lightsalt spray, explosive shock, and many more. These requirements extend beyond and interact with the electrical design. An electronics assembly consists of component devices, circuit card assemblies CCAsconnectors, cables and components such as transformers, power supplies, relays, switches, etc.
Many electrical products require the manufacturing of high-volume, low-cost parts such as enclosures or covers by techniques such as injection molding, die casting, investment casting, and so on. The design of these products depends on the production method and require careful consideration of dimensions and tolerances and tooling design. Some parts may be manufactured by specialized processes such as plaster- and sand-casting of metal enclosures.
In the design of electronic products, electronic packaging engineers perform analyses to estimate such things as maximum heermiticity for components, structural resonant frequencies, and dynamic stresses and deflections under worst-case environments.
Electronic packaging – Wikipedia
Such knowledge is important to prevent immediate or premature electronic product failures. A designer must balance many objectives and practical considerations when selecting packaging methods.
Punched and formed sheet metal is one of the oldest types of electronic packaging. It can be mechanically strong, provides electromagnetic shielding when the product elecrtonic that feature, and is easily made for prototypes and small production runs hermitciity little custom tooling expense. Gasketed metal castings are sometimes used to package electronic equipment for exceptionally severe environments, such as in heavy industry, aboard ship, or deep under water.
Aluminum die castings are more common than iron or steel sand castings. Electronic packages are sometimes made by machining solid blocks of metal, usually aluminum, into complex if. They are fairly common in microwave assemblies for aerospace use, where precision transmission lines require complex metal shapes, in combination with hermetically sealed housings.
Six Sigma: Hermeticity Testing
Quantities tend to be small; sometimes only one unit of a custom design is required. Piece part costs are high, but there is little or no cost for packwges tooling, and first-piece deliveries can take as little as half a day. The tool of choice is a numerically controlled vertical milling machine, with automatic translation of computer-aided design CAD files to toolpath command files.
Molded hermitocity cases and structural parts can be made by a variety of methods, offering tradeoffs in piece part cost, tooling cost, mechanical and electrical properties, and ease of assembly. Examples are injection molding, transfer molding, vacuum forming, and die cutting.
Pl can be post-processed to provide conductive surfaces.
Formally called “encapsulation”, potting consists of immersing the part or assembly in a liquid resin, then curing it. Potting hermoticity be done in a pre-molded potting shell, or directly in a mold. Today it is most widely used to protect semiconductor components from moisture and mechanical damage, and to serve as a mechanical structure holding the lead frame and the chip together.
Pavkages earlier times it was often used to discourage reverse engineering of proprietary products built as printed circuit modules.
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It is also commonly used in high voltage products to allow live parts to be placed closer together, so that the product can be smaller. This also excludes dirt and conductive contaminants such as impure water from sensitive areas.
Another use is to protect deep-submergence items such as sonar transducers from collapsing under extreme pressure, by filling all voids. Potting can be rigid or soft. When void-free potting is required, it is common pavkages to place the product in off vacuum chamber while the resin is still liquid, hold a hermigicity for several minutes to draw the air out of internal cavities and the resin itself, then release the vacuum.
Atmospheric pressure collapses the voids and forces the liquid resin into all internal spaces.
Vacuum potting works best with resins that cure by polymerization, rather than solvent evaporation. Porosity Sealing or Resin Impregnation is similar to potting, but doesn’t use a shell or a mold. Parts are submerged in a polymerizable monomer or solvent-based low viscosity plastic solution. The pressure above the fluid is lowered to a full vacuum. After the vacuum is released, the fluid flows into the part.
Curing can consist of polymerizing the internal resin or evaporating the solvent, which leaves an insulating dielectric material between different voltage components. The main application of vacuum impregnation porosity sealing is in boosting the dielectric strength of transformers, solenoids, lamination stacks or coils, and some high voltage components.
It prevents ionization from forming between closely spaced live surfaces and initiating failure. Liquid filling is sometimes used as an alternative to potting or impregnation. It’s usually a dielectric fluid, chosen for chemical compatibility with the other materials present. This method is used mostly in very large electrical equipment such as utility transformers, to increase breakdown voltage.
It can also be used to improve heat transfer, especially if allowed to circulate by natural convection or forced convection through a heat exchanger. Liquid filling can be removed for repair much more easily than potting. Conformal coating is a thin insulating coating applied by various methods. It provides mechanical and chemical protection of delicate components. It’s widely used on mass-produced items such as axial-lead resistors, and sometimes on printed circuit boards.
Herimticity can be very economical, but somewhat difficult to achieve consistent process quality. See Conformal coatingParylene. Glop-top is a variant of conformal coating used in chip-on-board assembly COB.
It packagrs of a drop of specially formulated epoxy  or resin deposited over a semiconductor chip and its wire bonds, to provide mechanical support and hermiticoty contaminants such as fingerprint residues which could disrupt circuit operation.
It is most commonly used in electronic toys and low-end devices.
In these, the individual diodes are mounted in an array that allows the device to produce a greater amount of luminous flux with greater ability to dissipate the resulting heat in an overall smaller package than can be accomplished by mounting LEDs, even surface mount types, individually on ellectronic circuit board.
Hermetic metal packaging began life in the vacuum tube industry, where a totally hermiticoty housing was essential to operation.
This industry developed the glass-seal electrical feedthrough, using alloys such as Kovar to match the coefficient of expansion of the sealing glass so as to minimize mechanical stress on the critical metal-glass bond as the tube warmed hermitictiy. Some later tubes used metal cases and feedthroughs, and only the insulation around the individual feedthroughs used glass. Today, glass-seal packages are used mostly in critical components and assemblies for aerospace use, where leakage must be prevented even under extreme changes in temperature, pressure, and humidity.
Examples are integrated circuit chips in ceramic Dual In-line Package form, or complex hybrid assemblies of chip components on a ceramic base plate. This type of packaging can also be divided into two main types: Printed circuits are primarily a electronlc for connecting components together, but they also provide mechanical structure. In some products, such as computer accessory boards, they’re all the structure there is.
This makes them part of the universe of electronic packaging. From Wikipedia, the free encyclopedia. This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged wlectronic removed. December Learn how and when to remove this template message. Electronic packaging Integrated circuit packaging List of integrated circuit packaging types Printed circuit board Surface-mount technology Through-hole technology.
It’s relatively common to find packages that pcakages other components than their designated ones, such as diodes or voltage regulators in transistor packages, etc. Retrieved from ” https: Industrial design Packaging Packaging microfabrication Chip carriers. Articles needing additional references from December All articles needing packahes references.