Hybrid integrated circuit

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An (orange-epoxy) encapsulated hybrid circuit on a printed circuit board. Hybridcircuit.jpg
An (orange-epoxy) encapsulated hybrid circuit on a printed circuit board.

A hybrid integrated circuit (HIC), hybrid microcircuit, hybrid circuit or simply hybrid is a miniaturized electronic circuit constructed of individual devices, such as semiconductor devices (e.g. transistors, diodes or monolithic ICs) and passive components (e.g. resistors, inductors, transformers, and capacitors), bonded to a substrate or printed circuit board (PCB). [1] A PCB having components on a Printed Wiring Board (PWB) is not considered a hybrid circuit according to the definition of MIL-PRF-38534.

Transistor semiconductor device used to amplify and switch electronic signals and electrical power

A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits.

Diode electronic component

A diode is a two-terminal electronic component that conducts current primarily in one direction ; it has low resistance in one direction, and high resistance in the other. A diode vacuum tube or thermionic diode is a vacuum tube with two electrodes, a heated cathode and a plate, in which electrons can flow in only one direction, from cathode to plate. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. Semiconductor diodes were the first semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other materials such as gallium arsenide and germanium are used.

Resistor Passive electrical component providing electrical resistance

A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses. High-power resistors that can dissipate many watts of electrical power as heat, may be used as part of motor controls, in power distribution systems, or as test loads for generators. Fixed resistors have resistances that only change slightly with temperature, time or operating voltage. Variable resistors can be used to adjust circuit elements, or as sensing devices for heat, light, humidity, force, or chemical activity.



"Integrated circuit" as the term is currently used refers to a monolithic IC which differs notably from a HIC in that a HIC is fabricated by inter-connecting a number of components on a substrate whereas an IC's (monolithic) components are fabricated in a series of steps entirely on a single wafer which is then diced into chips. [2] Some hybrid circuits may contain monolithic ICs, particularly Multi-chip module (MCM) hybrid circuits.

Integrated circuit electronic circuit manufactured by lithography; set of electronic circuits on one small flat piece (or "chip") of semiconductor material, normally silicon

An integrated circuit or monolithic integrated circuit is a set of electronic circuits on one small flat piece of semiconductor material that is normally silicon. The integration of large numbers of tiny transistors into a small chip results in circuits that are orders of magnitude smaller, faster, and less expensive than those constructed of discrete electronic components. The IC's mass production capability, reliability, and building-block approach to circuit design has ensured the rapid adoption of standardized ICs in place of designs using discrete transistors. ICs are now used in virtually all electronic equipment and have revolutionized the world of electronics. Computers, mobile phones, and other digital home appliances are now inextricable parts of the structure of modern societies, made possible by the small size and low cost of ICs.

Multi-chip module

A multi-chip module (MCM) is generically an electronic assembly where multiple integrated circuits, semiconductor dies and/or other discrete components are integrated, usually onto a unifying substrate, so that in use it is treated as if it were a single component . Other terms, such as "hybrid" or "hybrid integrated circuit", also refer to MCMs.

Hybrid circuits are often encapsulated in epoxy, as shown in the photo. A hybrid circuit serves as a component on a PCB in the same way as a monolithic integrated circuit; the difference between the two types of devices is in how they are constructed and manufactured. The advantage of hybrid circuits is that components which cannot be included in a monolithic IC can be used, e.g., capacitors of large value, wound components, crystals, inductors. [3]

Epoxy family of polymer

Epoxy is either any of the basic components or the cured end products of epoxy resins, as well as a colloquial name for the epoxide functional group. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups.

Thick film technology is often used as the interconnecting medium for hybrid integrated circuits. The use of screen printed thick film interconnect provides advantages of versatility over thin film although feature sizes may be larger and deposited resistors wider in tolerance. Multi-layer thick film is a technique for further improvements in integration using a screen printed insulating dielectric to ensure connections between layers are made only where required. One key advantage for the circuit designer is complete freedom in the choice of resistor value in thick film technology. Planar resistors are also screen printed and included in the thick film interconnect design. The composition and dimensions of resistors can be selected to provide desired values. The final resistor value is determined by design and can be adjusted by laser trimming. Once the hybrid circuit is fully populated with components, fine tuning prior to final test may be achieved by active laser trimming.

Laser trimming

Laser trimming is the manufacturing process of using a laser to adjust the operating parameters of an electronic circuit.

Thin film technology was also employed in the 1960s. Ultra Electronics manufactured circuits using a silica glass substrate. A film of tantalum was deposited by sputtering followed by a layer of gold by evaporation. The gold layer was first etched following application of a photo resist to form solder compatible connection pads. Resistive networks were formed, also by a photo resist and etching process. These were trimmed to a high precision by selective adonization of the film. Capacitors and semiconductors were in the form of LID (Leadless Inverted Devices) soldered to the surface by selectively heating the substrate from the underside. Completed circuits were potted in a diallyl phthalate resin. Several customized passive networks were made using these techniques as were some amplifiers and other specialized circuits. It is believed that some passive networks were used in the engine control units manufactured by Ultra Electronics for Concorde.

Some modern hybrid circuit technologies, such as LTCC-substrate hybrids, allow for embedding of components within the layers of a multi-layer substrate in addition to components placed on the surface of the substrate. This technology produces a circuit that is, to some degree, three-dimensional.

Three-dimensional space geometric three-parameter model of the physical universe

Three-dimensional space is a geometric setting in which three values are required to determine the position of an element. This is the informal meaning of the term dimension.

Steps in manufacturing Solid Logic Technology hybrid wafers used in the IBM System/360 and other IBM computers of the mid-1960s. The process starts with a blank ceramic wafer 1/2 inch square. Circuits are laid down first, followed by resistive material. The circuits are metalized and the resistors trimmed to the desired value. Then discrete transistors and diodes are added and the package encapsulated. Display at the Computer History Museum. IBM SLT wafers.agr.JPG
Steps in manufacturing Solid Logic Technology hybrid wafers used in the IBM System/360 and other IBM computers of the mid-1960s. The process starts with a blank ceramic wafer 1/2 inch square. Circuits are laid down first, followed by resistive material. The circuits are metalized and the resistors trimmed to the desired value. Then discrete transistors and diodes are added and the package encapsulated. Display at the Computer History Museum.

Other electronic hybrids

In the early days of telephones, separate modules containing transformers and resistors were called hybrids or hybrid coils; they have been replaced by semiconductor integrated circuits.

Hybrid coil

A hybrid coil is a transformer that has three windings, and which is designed to be configured as a circuit having four ports that are conjugate in pairs.

In the early days of transistors the term hybrid circuit was used to describe circuits with both transistors and vacuum tubes; e.g., an audio amplifier with transistors used for voltage amplification followed by a vacuum tube power output stage, as suitable power transistors were not available. This usage, and the devices, are obsolete, however amplifiers that use a tube preamplifier stage coupled with a solid state output stage are still in production, and are called hybrid amplifiers in reference to this.

See also

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Surface-mount technology method for producing electronic circuits

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Monolithic microwave integrated circuit

A Monolithic Microwave Integrated Circuit, or MMIC, is a type of integrated circuit (IC) device that operates at microwave frequencies. These devices typically perform functions such as microwave mixing, power amplification, low-noise amplification, and high-frequency switching. Inputs and outputs on MMIC devices are frequently matched to a characteristic impedance of 50 ohms. This makes them easier to use, as cascading of MMICs does not then require an external matching network. Additionally, most microwave test equipment is designed to operate in a 50-ohm environment.

IBM Solid Logic Technology

Solid Logic Technology (SLT) was IBM's method for packaging electronic circuitry introduced in 1964 with the IBM System/360 series and related machines. IBM chose to design custom hybrid circuits using discrete, flip chip-mounted, glass-encapsulated transistors and diodes, with silk screened resistors on a ceramic substrate, forming an SLT module. The circuits were either encapsulated in plastic or covered with a metal lid. Several of these SLT modules were then mounted on a small multi-layer printed circuit board to make an SLT card. Each SLT card had a socket on one edge that plugged into pins on the computer's backplane.

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Precision Monolithics, Inc. also known as PMI, was an American company based in Santa Clara, California, that developed and produced mixed signal and linear integrated circuits (ICs). It was a pioneer in the fields of digital-to-analog converters and operational amplifiers.

Through-silicon via

In electronic engineering, a through-silicon via (TSV) or through-chip via is a vertical electrical connection (via) that passes completely through a silicon wafer or die. TSVs are high performance interconnect techniques used as an alternative to wire-bond and flip chips to create 3D packages and 3D integrated circuits. Compared to alternatives such as package-on-package, the interconnect and device density is substantially higher, and the length of the connections becomes shorter.

In microelectronics, a three-dimensional integrated circuit is an integrated circuit manufactured by stacking silicon wafers or dies and interconnecting them vertically using, for instance, through-silicon vias (TSVs) or Cu-Cu connections, so that they behave as a single device to achieve performance improvements at reduced power and smaller footprint than conventional two dimensional processes. 3D IC is just one of a host of 3D integration schemes that exploit the z-direction to achieve electrical performance benefits.

Thick-film technology is used to produce electronic devices such as surface mount devices, hybrid integrated circuits and sensors.

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The idea of integrating electronic circuits into a single device was born when the German physicist and engineer Werner Jacobi developed and patented the first known integrated transistor amplifier in 1949 and the British radio engineer Geoffrey Dummer proposed to integrate a variety of standard electronic components in a monolithic semiconductor crystal in 1952. A year later, Harwick Johnson filed a patent for a prototype integrated circuit (IC).

Co-fired ceramic

Co-fired ceramic devices are monolithic, ceramic microelectronic devices where the entire ceramic support structure and any conductive, resistive, and dielectric materials are fired in a kiln at the same time. Typical devices include capacitors, inductors, resistors, transformers, and hybrid circuits. The technology is also used for robust assembly and packaging of electronic components multi-layer packaging in the electronics industry, such as military electronics, MEMS, microprocessor and RF applications.

A printed electronic circuit (PEC) was an ancestor of the hybrid integrated circuit (IC). PECs were common in tube (valve) equipment from the 1940s through the 1970s.

In integrated circuits (ICs), interconnects are structures that connect two or more circuit elements together electrically. The design and layout of interconnects on an IC is vital to its proper function, performance, power efficiency, reliability, and fabrication yield. The material interconnects are made from depends on many factors. Chemical and mechanical compatibility with the semiconductor substrate, and the dielectric in between the levels of interconnect is necessary, otherwise barrier layers are needed. Suitability for fabrication is also required; some chemistries and processes prevent integration of materials and unit processes into a larger technology (recipe) for IC fabrication. In fabrication, interconnects are formed during the back-end-of-line after the fabrication of the transistors on the substrate.


  1. "Tell me... Just what is a Hybrid Integrated Circuit?". ES Components. September 7, 2017. Retrieved 29 April 2019.
  2. "Difference between Monolithic ICs and Hybrid ICs (integrated circuits)". Polytechnic Hub. March 2, 2017. Retrieved 29 April 2019.
  3. William Greig, Integrated Circuit Packaging, Assembly and Interconnections, Springer Science & Business Media, 2007, ISBN   0387339132, p.62-64