the hybrid microcircuit micromodule ; solid logic technology vintage computer chip,...

Vintage Computer Chip, Semiconductor & Transistor Memorabilia

Vacuum Tubes > Transistors > Hybrid Circuits > Integrated Circuits

The Hybrid Microcircuit (1958-68)

A Hybrid Microcircuit is a miniaturized electronic circuit constructed of individualsemiconductor devices, as well as passive components, bonded to a substrate or circuit

board.

Some Memorabilia with Hybrid Microcircuits in them

Home

Our Collection

Search our Site

Resources for Collectors

Contact Us

Sitemap

The Hybrid Microcircuit Micromodule & Solid Logic Techn... http://www.chipsetc.com/the-hybrid-microcircuit.html

1 of 9 10/19/11 9:13 AM

Interconnecting Electronic Circuits - The birth of the Micro-Module

Before the invention of the IC, electronic equipment was composed of discrete components liketransistors, which serve as both switches and amplifiers; resistors, which impede the flow of electrons;and capacitors, which store them. These components, often simply called "Discretes", weremanufactured separately and were wired or soldered together onto Masonite-like circuit boards.Discretes took up a lot of room and were expensive and cumbersome to assemble, so engineersbegan, in the mid-1950s, to search for a simpler approach.

For almost 50 years after the turn of the 20th century, the electronics industry had been dominated byvacuum tube technology. But vacuum tubes had inherent limitations. They were fragile, bulky,unreliable, power hungry, and produced considerable heat.

It wasn't until 1947, with the invention of the transistor by Bell Telephone Laboratories, that the vacuumtube problem was solved. Transistors were miniscule in comparison, more reliable, longer lasting,produced less heat, and consumed less power. The transistor stimulated engineers to design evermore complex electronic circuits and equipment containing hundreds or thousands of discretecomponents such as transistors, diodes, rectifiers and capacitors. But the problem was that thesecomponents still had to be interconnected to form electronic circuits, and hand-soldering thousands ofcomponents to thousands of bits of wire was expensive and time-consuming. It was also unreliable;every soldered joint was a potential source of trouble. The challenge was to find cost-effective, reliableways of producing these components and interconnecting them...

The Micro-Module (1958-1964)

One stab at a solution was the Micro-Module (also know as a Micromodule) program, sponsored by theU.S. Army Signal Corps. The idea was to make all the components a uniform size and shape, with the


2 of 9 10/19/11 9:13 AM

wiring built into the components. The modules then could be snapped together tomake circuits, eliminating the need for wiring the connections. The micromodule system called for piling tiny wafers of discretes on top of eachother like dishes. Connecting wires ran up the sides of the stacks through holes inthe wafers. Micromodules were not only somewhat easier to make thanconventional electronic systems, they were also a good deal smaller: asix-component module was about the size of the sharpened cone of a pencil.

In the summer of 1958, a young engineer by the name of Jack S. Kilby went towork for Texas Instruments, which by then had earned a reputation for itself as aninnovative manufacturer of transistors. Kilby was slated to work on TI'smicromodule program, but the army's system seemed to him to be unnecessarilycomplicated. He wondered whether it would be possible, instead of stackingdiscretes on top of each other, to fabricate all the electronic components -transistors, resistors, and the like - out of the same piece of material. It occurredto him that a properly engineered slice of germanium might be made to act as awhole slew of components, much as a tapestry can be embroidered with anynumber of designs and colors.

As computer systems grew more complex, engineers sought simpler ways to interconnect thethousands of transistors they employed. Government agencies funded micro-module and multi-chiphybrid circuit projects in search of a solution to this problem. In 1952, G. W. A. Dummer of England'sTelecommunications Research Establishment proposed "With the advent of the transistor and the workin semiconductors generally, it seems now possible to envisage electronic equipment in a solid blockwith no connecting wires."

As computer systems grew more complex, engineers sought simpler ways to interconnect thethousands of transistors they employed. Government agencies funded micro-module and multi-chiphybrid circuit projects in search of a solution to this problem. A hybrid integrated circuit, HIC, hybridmicrocircuit, or simply hybrid is a miniaturized electronic circuit constructed of individual devices, suchas semiconductor devices (transistors & diodes) and passive components (resistors, inductors,transformers & capacitors), bonded to a substrate or printed circuit board (PCB). Hybrid circuits areoften encapsulated in epoxy. A hybrid circuit serves as a component on a PCB in the same way as amonolithic integrated circuit; the difference between the two types of devices is in how they areconstructed and manufactured. The advantage of hybrid circuits is that components which cannot beincluded in a monolithic IC can be used.

MICROMODULES: THE ULTIMATE PACKAGE (Army research) Electronic Engineering Times, December 27, 1999, Rostky, George

It looked like a fountain pen, albeit a fat one, but it was really a radio. The U.S. Army liked it, not justbecause it was very small for a radio, but because it introduced a new concept in circuit packaging—small size and uniform construction. RCA's Surface Communications Division showed this pen-sizeradio to the U.S. Army in October 1957, shortly after the Russians launched Sputnik, anddemonstrated that the world's leader in technology, the Americans, were way behind. At a time whenthe American military was desperate to catch up, this ultimate in packaging density, called amicromodule, could be just the answer.

The Army loved the concept. In April 1958, it awarded RCA a $5 million contract in what becameknown as the Micromodule Program. Just a few months later, in January 1959, RCA's AerospaceCommunications and Controls Division built a stable inertial-guidance platform using micromodules.

And just two months after that, in March, at the annual show and convention of the Institute of RadioEngineers (an IEEE predecessor), at a joint press conference with the Signal Corps, RCA announcedthe commercial availability of Micromodule Designer's Kits for breadboards.

Then, in July 1959, the Army added $2.4 million to RCA's contracts—for new microelements, as theywere called—and for higher-temperature capabilities for some elements. In February 1960, the Armyadded $8 million for demonstration helmet radios and miniature computers.

RCA's Micro-Module


3 of 9 10/19/11 9:13 AM

The micromodule, as the package was called, was fundamentally akin to the short-lived ProjectTinkertoy, which the Navy funded in 1951. Tinkertoys were based on using 5/8-inch-square ceramicwafers, each of them bearing a discrete component. That concept was the brainchild of Robert Henryat the National Bureau of Standards.

The Micromodule Program was to use smaller ceramic wafers, 0.36-inch square, with three solderridges along each edge. These squares were stacked and interconnected by riser wires soldered tothose solder ridges, where appropriate. The entire module could be encapsulated and, depending onthe circuitry involved, might be from 0.4- to 0.8-inch high. Modules could be designed for almost anysystem.

Production of a wafer element could be automated. Individual microelements might contain almost anycomponent. While RCA was the prime contractor, more than 60 producers participated in developingindividual microelement components and wafers. And here was another advantage. Individualsuppliers became component specialists and experts. Some companies would specialize in filmcapacitors; others would do aluminum or tantalum electrolytic capacitors; still others would offerthin-film or thick-film resistor networks; inductors; trimming potentiometers; and bare transistor chips(called "dot" transistors). The top-most wafer could support a socket for a miniature 7- or 9-pin vacuumtube, but that feature was never used, as transistors were already in widespread use.

It was more than obvious that the micromodule was the circuit package for the future. It was moreexpensive than conventional printed-circuit packages, but follow-on costs, like maintenance andlogistics (including storage, handling and training) were lower.

The initial cost was indeed higher. In 1962, a 10-component micromodule cost $52 compared with$20.45 for a printed-circuit-board equivalent. But micromodule costs were expected to plummet withincreased production in 1963 and 1964, with costs approaching or even slipping below conventional-package prices, and declining rapidly beyond that.

Reliability soared. Based on millions of testing hours, RCA reported that the micromodule proved to besix times as reliable as conventional military circuits and 60 times as reliable as tube circuits, stillwidely used. Most wonderful, circuit density was beyond the wildest imagination of a few years earlier.RCA's helmet radio had the equivalent of 210,000 components per cubic foot. And the future might seepackages with a staggering 600,000 parts per cubic foot. This was a remarkable contrast to 100,000parts per cubic foot in the most advanced conventional circuitry.

For once, the future was clear. In August 1962, the Army's chief signal officer, Major General Earle F.Cook, reported that the micromodule program had proved so successful that the Army's deputy chief ofstaff for logistics had issued a directive to "take prompt and positive action to incorporate themicromodule concept as appropriate."

Cook reported that the Army expected to commit $8 million for micromodule equipment in fiscal 1963,about double the 1962 funding. Some $18 million had already been invested in the program.

In his 1962 report—at a joint press conference with RCA—Cook looked back fondly at the March 1959Signal Corps-plus-RCA press conference when the micromodule was introduced to the world withgreat expectations. As he listed a large number of micromodularized equipment that was to bepurchased, Cook expounded on the great benefits already realized as a result of the micromodulerevolution since that 1959 press conference.

The Future

Cook did note that the micromodule would accommodate advanced integrated circuitry, "logically,through evolution, rather than by revolution. Such developments," he said, "normally mature bit-by-bitover a protracted period of time, rather than suddenly appearing as an entire operational system. Theindustry anticipates a long period of applications of the new devices in hybrid combinations withconventional components."

Cook was clearly aware that the "advanced integrated circuitry," which micromodules wouldaccommodate through evolution over a protracted period of time, were beginning to attract someattention.

But he may not have been aware of another press conference that took place in March 1959, possibly


4 of 9 10/19/11 9:13 AM

RCA Micro Modules mounted on a PCB Sub Assemblies of the RCA MicroModule

just a few doors from the Signal Corps-RCA press conference. That's when Texas Instrumentsannounced the work of an engineer, Jack Kilby, who had joined the company a year earlier.

Kilby had developed what TI called a "solid circuit," and what TI hailed as the ultimate inmicrominiaturization. Kilby, it turned out, had a great deal to do with the fact that micromodules did notaccommodate advanced integrated circuitry. In fact, Kilby was a trigger for the demise of themicromodule program.

Instead of mounting individual components on individual ceramic wafers, Kilby thought it would be niceto manufacture all circuit components in one operation with one material. He was not the first to harborthat idea. Others included G.W.A. Dummer of the Royal Radar Establishment in England who, in 1952,spoke of the possibility of blocks of equipment with no connecting wires.

Solid circuits

At its March 1959 press conference, TI introduced two Kilby "solid circuits," a two-transistor flip-flopand a one-transistor phase-shift oscillator, each at $450. (Competing thin-film modules cost less than$50, so the solid circuit appeared to have a future only where cost was not a consideration.) Each solidcircuit was built on a single semiconductor chip. Within a year, TI had a line of six solid circuits—all inflat packs—including gates and flip-flops. The dual-inline package, invented by Bryant C. (Buck)Rogers at Fairchild, came later.

Though the name "solid circuit" didn't stick, "integrated circuits," as such devices came to be known,did have a rather successful future, even surpassing TI's declaration in 1959 that these products"represented the ultimate in microminiaturization."

Shortly after TI's introduction of these ICs, Fairchild became the second vendor, with IC's invented byFairchild co-founder Robert Noyce, based on the planar process developed by Fairchild's Jean Hoerni.These IC's and those that followed from many vendors, all using the planar process, took over theworld and killed the micromodule program.

Yet the micromodule program was a huge success. While the program lasted, micromodule packagesaccommodated 675 different circuits. In 1963, micromodule production at RCA alone reached a peakof 10,000 units a month. And micromodules met or surpassed all the initial goals.

By late 1964, the initial enthusiasm for micromodules was gone and there were no further majorcommitments. The early hesitancy in adopting integrated circuits was replaced by eagerness as pricesplummeted. ICs began to flourish as micromodules began to vanish.

Some Memorabilia with Micro-Modules in them


5 of 9 10/19/11 9:13 AM

IBM System 360 SLT Ad (1964)

RCA MicroModule assemby paperweight

Transistorized Modules (early 1960s)

Some computer makers such as Burroughs used plug-in typeModules that allowed multiple Transistors, Resistors andother components to be efficiently arranged inside. An arrayof these small modules were plugged into printed circuitboards allowing for even greater density than the earliertechnology which mounting the components individually andspaced apart on a circuit board.

IBM's Solid Logic Technology - SLT (1964-1968)

The Solid Logic Technology (SLT), introduced in 1964 by IBM inSystem/360, was the industry's first high-volume, automatic,microminiature production of semiconductor circuits. Mounted on1/2-inch-square ceramic modules, the SLT circuits were denser,faster and required less power than the previous generation oftransistor technology. In 1968 IBM's widely used Solid LogicTechnology modules achieved a reliability rate one thousand timesgreater than its vacuum tube predecessors.

IBM developed Solid Logic Technology (SLT) for the System/360computer family in 1964 prior to the ability of monolithic IC's to meetthe cost and speed demands of large computers. Transistor chipsand passive components mounted on 0.5" square ceramic moduleswith vertical pins consumed less power and space while offeringfaster speed and superior reliability compared to printed-circuit boards with packaged transistors. IBMproduced hundreds of millions of SLT modules in a highly-automated, specially-built plant in EastFishkill, NY.

Solid Logic Technology was IBM's method for packaging electronic circuitry introduced in 1964 withthe IBM System/360 mainframe computer series and related machines. IBM chose to design customhybrid circuits using discrete, flip chip mounted glass--encapsulated transistors and diodes, with silk

A 4 transistor module from a Burroughs B5500 Computer


6 of 9 10/19/11 9:13 AM

Transistor chips being placed on an IBM SLT Logic Chip using AutomatedManufacturing (1964)

IBM SLT Chips

screened resistors on a ceramic substrate. The circuits were either encapsulated in plastic or coveredwith a metal lid. Several of these were then mounted on a small multi-layer printed circuit board tomake an SLT module. Each SLT module had a socket on one edge that plugged into pins on thecomputer's backplane (the exact reverse of how most other company's modules were mounted). SLTwas a revolutionary technology for 1964 with the reliability improvements over other assemblytechniques helping propel the IBM/360 mainframe family to overwhelming success during the 1960s.SLT research produced ball chip assembly, wafer bumping, trimmed thick film resistors, printeddiscrete functions, chip capacitors and one of the first volume uses of hybrid thick film technology.

Some Memorabilia with Solid Logic Technology in them


7 of 9 10/19/11 9:13 AM

Evolution of IBM 1960's Logic Chip Packaging Technology

Solid Logic Technology (SLT) introduced in 1964

IBM's first generation of Solid Logic Technology (SLT) chips usedonly one circuit per module and the had 12 pins.

The Next Generations of the IBM SLTThe same basic packaging technology (both device and module) was also used for the

devices that replaced SLT as IBM gradually transitioned from hybrid integrated circuits tomonolithic integrated circuits:

Solid Logic Dense (SLD) introduced in 1967

Solid Logic Dense (SLD) increased packaging density and circuitperformance by mounting the discrete transistors and diodes on top ofthe substrate and the resistors on the bottom. The SLD had two to fivecircuits per module and 16 pins.

Advanced Solid Logic Technology (ASLT) 1967

Advanced Solid Logic Technology (ASLT) increased packaging density and circuitperformance by stacking two substrates in the same package.

Monolithic System Technology (MST) introduced in 1968

Monolithic System Technology (MST) increased packaging density andcircuit performance by replacing discrete transistors and diodes withone to four monolithic integrated circuits (resistors now external fromthe package on the module). The MST was introduced with six circuitsper module but eventually had up to 40 circuits per module. It had 16pins.


8 of 9 10/19/11 9:13 AM

Vacuum Tubes > Transistors > Hybrid Circuits > Integrated Circuits

Resources for Collectors Home

Copyright © 2009 ChipsEtc.com. All Rights Reserved. Other product and company names shown may be trademarks of their respective owners.


9 of 9 10/19/11 9:13 AM

the hybrid microcircuit micromodule ; solid logic technology vintage computer chip,...

Documents