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DIAMOND ORDNANCEC F;)ZE L.ABORATORIESWASHINGTON~ 25, D. C.

TN3-9101 TR-G 1DA506-01-001 17 June 1958 10 PagesDOFPL Proj. 50150

MICROMINIATURIZATION OF INTERNAL ELECTRONICS"IMICROELECTRONICS" (U)

T. A. Prugh

FCr 'THE COMMANDER.

SLabotc~y 50

'a isfraitt"rI itt'&Nvao.e for taffertwito or1oats 001'~%a tf id&r ."If4l Iattit vitl t ei bat 2eI&Ied to say Ciba.

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Wtfl. fr aditinal copies of this repo tabauldb. ,ddrql..~'I-A3TIA, Arlit.ilo., Hall Staticm, Arlington 1:. VirgInte.

FOREWORD

The text oi this report was given as a paper at the Second NationalConvention on Military Electronics, sponsored by the PGME, IRE, atWashington, D. C., on June 16 - 17 - 18, 1958.

(

KICHOMINIAtIMUATION OF IMZU7iAL ELEMTOITCS -"MICROEUCORICS"

By: T. A. Prugh, Diamond Ordnance Fuze Laboratories

Abotroot scaled down In size. The amount of red-icton

Is roughly in proportion to the reduction inThis paper is a progress ,.sport on one ap- Jze occurring between commerciltly available

proach to the problem of fabricating small elec- i watt resistors and 1/10th watt resistor-.tronic circuits. Printed circuit tuid metal This ipproarh has brought up new problems inewporation techniques have been used to produce fine line etching, component insertion and dipt blnary counter module occupying less than Lulierlng because of the closer physalc: toler-

I P.0 of a cubic inch. Included in the module unces demanded. However, the progress initre two transistora, two diodes, two capacitors, etched board technology has made the sL|,; lessand eight resistors. Problems and solutions are difficult.d ,,soribed in the areas of circuit design, pas-stvo t'ompoient, semiconductor c, ponent, and en- Figure I shows neyrd modules mwLe by thisapsulatlon. Extraolation of . esent techniques approach. About 150 component paLrt,., X trians-

shows promise of permitting a denstty of 2 istors plus associated parts, or lU binarytran.4itort plus associated co.ponents per cubic counter stages per cubic inch is the possibleinch. density. Interconnection of the individuad

modules in accomplished by meais of a oe--ondtryIetched board.

Mode-rn weaponi are placing increased de- Method of Quantitative Comparl3onmands on ordnance electronics. One severereluirement is the need to put more electronics A brief digression is in (,,,der to discus--in les' s space. The Diamond Ordnance Fuze how to compare the various fabriration nchemesLaboratories have been active for more than a in a quantitative manner. Thres densit ies willdecade in the areas of printed circuitry a.nd sub- be used:miniaturization. Approximately a year ago ateam of circuit, component, and semiconductor (1) Total. nber of component parts perpeople wns formed to concentrate on the problem cubic inch.of making radically small electronics. This (2) Number of transistors per cubic inch,present paper Is a progress report on the year Other component parts are asnumtedof activity in microminiaturization at DOFL. fitted in also.

(5) Number of binary .'ounter stag:s perTwo stages in the evolution of the methods cubic inch.

of making small electronic packages 'will bedescribed. The first step will be covered The component man generelly llkts the firstbriefly as it is a logical extension of the density. The circuit min likes the seccrd be-etched wiring board incorporating separately ceuse it is an indication of th, number o:'rased component parts such as the Signal Corps active elements. The logic designer favori th'Auto-Sembly 1

techniqu-. The second step Is the third because it is a measure of the logicialutilization of printed circuit techniques wher- blocktc that can be fit into a cubic inch.ever possible.

The term "internal electronics" is used to )OFL PD Approach

describe that portion of an electronic system At pointed out by Brunetti' the significantthat operates at low power level and is pri- reduction in s'ize comes about by eliminating in-marily concerned with the handling arA proc- dividwil. part cases mnd blending the parts Into,essing cf information. Not Included are the one het rogeneous mutt. The integrated-casrl,7,nustul high power stages required to drive printed circuit approach under study nt DOFL 19motors, antennae or display devices. These t itnrt in this dprchtinn.latter circul.a occur at the boundary betweenthe electronic syslem and the environment sur- Some general guidelines were used torcunding it. direct the search for lecthniques. An mentioned

above no individua component protection was to"Hearing Aid" Approach be used unless absolutely necessa,-y. Se'ouidly,

rather than attempting to reduce all threeThe advent of small resistors, capacitors, dimensions an equal am,,unt it an decided toand transistors as used by the hearing aid In- concentrate on a "two dimensional" module withdustry has permitted etched wiring boards to be the third dimension, i.e., the thi,:knese, is

thin as ponrible. This permits approtchingIs.o. Bassler, "The Anplicatlon of Auto-Sembly zero volume but with a finite area tht canto the Mih.ile Field," Convention Record nf_First T(ntiona. Convention on Military 'C. Brunetti, "A New Venturr into Micreslolr-raectronlca, 19.7. pp. 10(9-11' turiz.tion," 19'7 lRE Convention Rcn,l.

pt. 6, pp. 5-10.

3ost Available Copy

still be 'eeo ,ut work4A ,&,. Thte third point Injection molding methods Iook attractit, forwit" t, detaki Ute letaL it performance out of large production runs.the Individumi component parts. This latterpoint "s particularly ilfportant when consider- The capacitors used are an experimentallng the poiibility of using caseless transia- type Made from reduced barium titanate. Thetorn. 0.01 1Lf capacitor is physically 0.1 inch squar-

and 8 mils thick. This type capacitor has airoh irm Areni very low voltage breakdown, a property which

does not prevent its use in the present modules.A number cr interrelated areas of work were

invoLved in the iuecettnful design and fabrl- The most difficult problems occur in ob-c.tivn or wrkltg mdutle'i. Included were: taining it satisfactory caselean transittor.

Mounting the die, lead attachment, and surfaceI. L ,oier of rtcreuit type and constants, protection constitute the major difficulties.2. )k)unting plate, conductor:n, resistorLI, The particular transistor type utilized in the

and capacitors. first operating modules is a diffuaed-bavei. Semiconductor c. Tponents (diodes and unit. The 145 m2 square die is cemented in a

transistorn), hole in the ceramic plate wlth epoxy plastic.Connections are made between the transistor

Additional arera. ben i worked on now are: electrodes and th- silver wiring pattern by anevaporated aluinum film. The precise dimen-

:T. ?rani.oi -dilode prot.(ti n from stonal control required s obtained by photo-contamitntt ion. lithographic techniques.iOver-all protection of a module.

ti. Intervotni.ctLion o' modules. An experimental module is shown in Figure 5.7. Optimum ,ompl'xi ty of mdulest. The back side i, identical in construction.

v. trnmnyfl I evulution. 'Mi- mil'e rl. - ' pattern, black resistor pat-tern, capacitor platen, and semiconductor

Th,- circuit chosen for exp'rim.*ntittIon in devices are clearly visible. This 21D appryit !hworkIM out the techniqueo uan a binary counter will permit a density of nbout 1500 com.ponentstage. This type circuit can be deoigned to parts, 200 trunb:storn plus anuoeu,1ted parts,op'crtite with bro'id merglna and thu; permLit or 100 binary counter stages per cubic inch.eafrly fabrication of working circuits for stdyunder dynamic rIttions. The circuit schematic The protection of the individual componentin shown in Figure 2. No attempt was mAe to parts and the completed modules Is being ap-obtain high fre-,l1 eney performance. The caps- proachOd t rr eq-rd adpects. The semi-cltora are large ersougli in cttpakcity for use with conductor devices are undoubtedly Ce mostlow-frrluency kudilo-type translatoru. vulnerable. 'he photoresist used to make '.;e

diffused bane type transistors has proven -u beThe counter circuit Is -iert.-f. in demmun a good surface protector. Other plastic ercap-

oct the ctmponent pnrts In 'teverml respects: uulants are being considered for tiuporaryprotection purposes. The present plan Is to

I. low frequency (au mentioned sbove), hermetically seal a number of interconnected:1. low voltage ,;r,,ttlon, modules into a common container. Poisoning of5. low -urrent operatlon, the semiconductor surfaces by contaminants from4. low transistor vurrent gal (1) the other component parts in the same sealed

peraitted, volume is being inv-stigated. If necessary it'. higl transistor I p:rmItted, may be possible to indivldually seal each6. resistor ratiosmO important tha, transistor or diode in its bole in the ceramic

Aboolutr vuflue,. plate.

In the fabrication of moAules mich of the The interconnection of power and signalte,'hnology developed In th, pust ten years for lines between modules must be done in an effi-printed c..¢cuitn hat, been directly applicable clent and practicfl fashion or the large volumewith proper ,cudILng down in usze. The mounting reduction theoreticialy obtainable will not be;,lite used in the mod2cut it a steatite ceramic uchieved. One face of a group of stackedwitrer I/ inch oquare by M ails thick. Theconductor pottern is a sIlk ticreened ,ilverpoint fired in place. The conductor width it 5J . Nall and J. W. Lathrop, 'Photolitho-n$pprotzimtely 50 ails. graphic Fabrication Techniques for Trns'ntorn

which are an Integral Part of a Printed cir-T-e- reolstors are 1nu, 0.)k :,creened oin cult," A paper presented at the 1957 Electron

the wafer and are a carbon composition similar Devices Meeting of the MfE PCM), Nov. 1, .1957,In chitra*terin.ttcs to cuvwercially isvilablrcomposition renintors. A 10K ohm resistor itapproximately 60 aIls nquArr and 1 ail thick.

rmiUl t:; ;tOnL t.,c used Ior interco.nections. The most important conideraton will then becomebinary count,!r moditle hot lead wires comirg out the proper geometric relationship of theone end. A amall etched interconnection board modules rather than good low resistance con-can be used tn u c;imilar fachion to the 'bearng netions. Power and snigal cornecttons wouldold" 'Lpprorrh. all be handled in the same manner. It should

be possible to reduce drastica.ly the ntuberAxA experimental technique being tried is of faulty and erratic connections.

to chemically deposit copper or screen silver;o :h: intereonnection pattern directly on one Conclusionsor more faces of the group of modules.

Figure h suymirlzen the evolution of f',b-A particularly troublesome question which riCation techniques a3 illustrated by a 10

mu ;t be veid In a qpecific system application statge binary counter. The top view showsIs: what er of componenta or ;Iegree of com- etched boards with standiard component parts.plexity shc module have? Making the The middle view is the "hearing aid" approach.modulets too Le will mean i larlge and com- The smll1 unit at the bottom shows the DOFLplicated intexonnection pattern. If the PD technique.modules &.. 7 complicated the yield in pro-duction will be low and the cost, to replace a The techniques described permit one todefective module will be high. In the present two orders of magnitude reduction in volumeresearch stage the hinary countor is ,;uffic- of electronic equipment used for infor..sitlonlIntly Involved to tax the techniques under handling purposes. Further research alonrttiy. logical extensions of the present methods show

promise of permitting ;verml thouoos! trons-Detn ilvd en vi romntILI atiw11i iLre needed tor un plus ancn'i t compnI ' ntn to r(n',y

to cheek the life anid rog,,in, s of the Inte- less than one cubic inch.g:rated-cone] eon minulen. Terperature rxtrmes,high humidity, shock, and vtbrition will un- It requires little Imagination to, sct , mainydoubtedly expose wedknesses in the techniques. potential benefits of thi;n compact electronics -

microelectronics - to the variou:; pho;s:; ofFuture possibilities tilitary electronics. More electroni(s; will

be able to go into n. given vr)Itme or even moreAlthough problems still exist i.- the fab- Important, electronic .ystemn never before (eon-

rication of the present size modules even sidere, portable will be easily carried insmaller ve'-.,s seem feasible. Two broad missiles, satellites, or by man.approaches are possible. The most direct isto scale down further the printed components and Acknowledgementscaseless semiconductor de-ices. A factor of twodecrease in each dimension seems practical and The work described in this progress reportwould give #ncth.r order of magnitude reduction in the result of the efforts of many people.in volume. Included are Edith Davies, N. J. Doctor,

Dr. J. W. Lathrop, .1, R, Nfl, A. A. Benderly,A second approach which has greeter poten- and Meyer Schwarz.

tial is to integrate the functions of resistors,capacitors, diodes, and transiators, to a muchgreater extent. In the present approach thevarious component part types are made inseparate distinct steps. If all component part!-could be fabricated from one type of material

by a single process, such Fin prin-ing or evap-oration, a much smaller and simpler modulewould result.

In the area of reliability a particularlydifficult problem is to assure solid ohmicInterconnections between modules. As sizen gudovn the difficulties rise rapidly. Onepromising approach is to use only capagitativeor inductive coupling between modules. The

qthin idea i an eztension of one proposed byW. D. Fuller and J. G. 3mith of Varo Mfg.Company in which only the signal connectionswould be made by capacitative coupling.

-ThT

U aj

Figure 1. "TtrvrIng Ald' A-pr.ach Figure 2. Binatry Counter Schematic

Figure 5. DOFL :'D Approach Figure 4. Evolution of Fabrication Techniques

1-2 RDTN3 OfDrI)T

4 ORDTU

5 - ASTIAArlington Hall StationArlington 12, Virginia

10 Jet Vropulsion laboratorieaCalifornIR In.stitute of TechnologyPrmadona, California

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24 Solid State Devi es Branch

Electron Devicep Division

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Andrews Air Force Base

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30 LibraryNational Bureau of Standards

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31 Commanding GeneralArmy Rocket and Guided Missile Agency

Redstone Arsenal, Alabama

32 Lt, Col. Ulrich, J.A./Iill l"W :,,J , ~

33 - 37 Kalmuh, R. P. / Vit Trump, .1., ('Q.0

38 Guarino, P.A., 2010

30 Kohler, 1. W. , "C. ,40 Aptitein, M. , 40. 041 Rotkin, 1. , 30. 042 Algor. M., 21.343 Yancy. R. , 32. 444 Yung, t.T., 52.045 Uirmatainen, T. M,., 246 Bradley, M.IR., 52,447 Nail, J.R.. 52.248 Lathrop. J.W., 52.249 Morey, F.C., 33.0

50 - 54 Doctor. N.J., 53.2-55- 50 Davies, E.M., 53.2

60 Franklin, P.J., 53.061 Hatcher, R.D., 44,0

62 Campagis-, J., 42.063 Horton, B.M., 41.064 Mead, 0., 44. 1

65 - 114 Prugh, T.A., 51.4115 Brenner, M., 63.3

116 - 117 DOFL LibraryIIS Laboratory 40 (Library)119 Technical Information 1lrareh OlterrI)

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TWO PAGES OF ABSTRACT CARIeV1 1'h 1IW

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