CA1309510C - Carrier continuous film for heat fusible materials - Google Patents

Abstract

CONTINUOUS CARRIER FILM FOR HEAT FUSIBLE MATERIALS
Abstract of the Disclosure A carrier film for heat fusible materials comprises a heat-resistant substrate which is option-ally water-soluble, a water-soluble pressure-sensitive adhesive coated on one surface thereof, and a remov-able release liner. The adhesive releasably retains on the surface of the substract a plurality of bodies of heat fusible material which may be arranged in a predetermined pattern to match the arrangement of printed circuit board or other components desired to be connected. The carrier film may be used to trans-port the bodies of heat fusible material to the de-sired location, and the adhesive functions to retain the in that location and in the predetermined pattern while heat is applied through the substrate to melt the bodies of heat fusible material and provide the desired connections, after which any residual adhes-ive, as well as any residual water-soluble substrate, may be removed using a conventional aqueous bath. The carrier film may advantageously be provides in the form of a continuous tape, along the length of which the predetermined pattern of bodies of heat fusible material may be repeated at appropriate intervals.
Method of assembling semiconductor electronic compo-nents utilizing the carrier film are also disclosed.

Description

CONTINUOUS CARRIER F~I~ FOR HEAT FUSIBL~ MATERIALS

Ei~ld o~ the Invention The present invention relates to the as~em-bly of electr~nic compsnent~, and specifically to a transport medium ~or heat fusibl~ materials, and more spe~i~ically to an apparatus and method for dispensing bodies of heat ~usible materlal and to methods ~r a~sembling ~omiconductor elec~r~nic components u~iliz-i~g such a medium.

Bac~ound of the Inven~n In the semiconductor electronic~ in~u6try, ~l~ctronic co~pon2nts ~uch as semi~onductor packages and p~intod circui~ boards are often assem~led using heat fu~ibl~ mat~rials such a~ conductiv~ solders which compri~e alloy~ o~ various metals such as gold, t~n, lead, bismuth ~nd indium. In general, the sol~er m~tgrial i8 u~ed to provide electrical and/or m~chan-ical conneCtiun8 between various electronic compon-en~s. For exampls, in ~ome appli~ations, the sold~r matarial i~ provided ~or use in conneCting metallic pins to ~ printed cl~cuit board, with the pins belng supported, before soldertng~ tn appropriate printed circuit board hol~ which are drilled with a pattern corraspon~ing to the pattern of the pin~ desired to be connec~ed. In ~ther applications, the sol~er materlal iB . first affixed to the periph~ry of a metallic lid to -2~ 3095 1 0 form a co~e~ wi h a rim of solder which ~s provided as a unit. The solder can then b~ used to connect the cov~r to and form a h~rmet~c seal for ~ metallic or ceramic container housing a ~miconduotor d~vice.
~n ei~her case, and in other applications as we~l, the ~ol~er matcrial i~ u~ually pre-formed into thin parS~ ("preformo") having fixed shap~s (e.g., circular donut-s~aped wa~herc, or s~uare or rectangu-lar ~rames) to facilitato thelr u5e on or in connec-tio~ with other printed circuit board components. In general, these bodies of solder material are arran~ed adjacent one or more other component~, and heat is applied to melt the solder, thereby ~ormi~g a bond or seal of solder material which may also provide an ele~rical conneetion~

DeScription of the Prior A~t In the prior art, ~arious methods and ~ppar-atus have been used to transport and dispense solder preforms on a sel~ctive and repetiti~P ba!~is. Origin-ally, the solder preform3 were brought in~o proximity with and then posi~ioned adjacent ~he components ~o be soldered either by hand or using tweezers, a process which was both lahor-intensive and ~ime-consuming. A
more advantag~ous method was later devised to automate this proces~ by mounting the solder prefor~s (together with metored amou~ts of solder ~lux) at rl~gular inter-vals on a continuous, hea~ resiS~ant sneet or f~lm having a plurality of spaced holes or compartmen~s a~ranged therein to match the number and spacing of the itemY to b~ 601dere~, w$th each hole or compart-ment a~commodating an individual solder preform and an appropriate amount of flux. ~he prior art sheet or film would function as a carri~r to transport the solder preforms to the location at which th~y wera to be us~d, and it might also include adhe~i~e ~ab~ adap-ted to r~tain the pr~forms in the de~lred locatlon and con~igurat~on while heat was applied t~rough the sheet or f~lm to m~lt all of th~ soldor pre~orms simultane-ously, thera~y providing a plurality o~ solder aonnec-~ions in one operat~on.
Th~ ma~or di~ad~antage of th~s~ prior art d~s~oncing mechanismB 1~ that it is di~ficult ~o re-move th~ film and e~p~c~ally the adhe~ive whiCh re-mains after th~ application o~ heat t~ melt the solderpreforms. Moreover, the prlor art do~s not adequ~tely provide for r~moval o~ exae~s flux aftar th~ soldering operation i3 comple':e.
It is th~re~ore a genexal object of the pre~ent invention to elim$nate these and other draw-bacX-~ of the prio~ art by providing an improved appar~
atu~ and met~od for transportin~ and dl~pensing ~older preforms for use ~n connection with celected printed circuit board ~omponent~, a~ well as ~mproved m~thods for connect~ng a plurali~y of ~miconductor electron~c component~ slmultaneously, utiliz~ such apparatus.
lt i~ a further ob~ect of the pre~ent inv~n-tion to provide an apparatus and method which spee~s up the ~older.ing process by facil~a~ing the r~moval of residual ~ilm, adhe~ve, and/or ~lux.
In th~ ~emiconductor ~lectronics industry, it has also becom~ conventional to util~ze a conduc-tive metallic sealin~ cover, comp~ising a gold-pl~ted lid having a solder pre~or~ ~rama prQ-attached about its periphery, in order to form a cov~r for and to seal hermetically the cavity o~ a se~iconductor pack-age whl¢h may contain an actlve Ln~egrated-c~rcuit silicon chip. Method~ o~ fabricating such conductive hermetic sealing covers are well-~nown, including for ~xample the ~pot-wRldlng proce~ dicclo~ed and claimed ~n ~.S. Patent No. 3,~46,190, ~nd ma~y m~llions of -4- --- l 30951 0 such co~ers are used each year.
Although the assembly method described in the aforementioned patent is satisfactory, it contem-plates that a preformed solder ring or "frame" will be superimposed upon a corresponding KOVAR*lid in a man-ual fashion, by disposing both the lid and the frame in a shallow cavity having dimensions only slightly larger than those of the lid, thereby insuring regis-tration between the frame and the periphery of the lid prior to subjecting these parts to a spot-welding attachment process. The major disadvantage of this procedure is that it is labor-intensive and slow.
It is therefore a further object of the present invention to provide an improved method for fabricating such hermetic sealing covers by providing a continuous dispensing means by which a plurality of solder preforms can be aligned in registration with a plurality of corresponding lids in an automated fash-ion.
Summary of the Invention In accordance with the invention, solder preforms are mounted at regular intervals on a contin-uous carrier film comprising a protective paper re-lease liner and a heat-resistant film substrate which is coated on one side with a water-soluble pressure-sensitive adhesive or binder. The substrate may op-tionally be made water-soluble as well, and the car-rier film, including the release liner, may advantage-ously be provided in the form of a tape or ribbon.
The tape functions as a carrier to transport the sol-der preforms to the location at which they are to be used, and the binder or adhesive facilitates the as-sembly process by retaining the solder preforms in thedesired location and configuration while heat is ap-* Trade Mark - i -5~ - 130~510 plied throu~h th~ s~bstrate to melt th~ ~older.
Thercafe~r, the recldual sub~trate can be removed by pe~lin~, or if lt is water-sol~ble, it can be di~-solved and washed ~way, along wi~h any r~sidual a~hes-S lv~, ln a conventl~n~l aqueo~ bath.
~ his ~ape arrangemen~ permit~ a plurality o~relatively ~all solder pre~orms to be mounted and t~en retained ln an array ( i . e ., $n any desired pat-rn or oonfigura~ion) to facilitat8 allgnment wlth0 printed circui~ bo~rd or other component~ alr~ady arranged ln a corresponding array. The tape can be wound onto a 8p~01, and can be providsd optionally with BproCXet ~oles running along one or both edg~s t~
enable its u e wit~ a pin-f~d mech~ni6m.
The ~nvention al~o encompa~ses method3 of simult~n~ously connectin~ a plurality of ~em~conduc~or electronic component~ to a printed c~rcui~ board util-izing solder pr~form~ di~posed on the carrier f~lm d~cxibed her~inabove, as well a~ method~ o~ di~-pen-~lng solder preformc utilizing that carri~r f$1~. The methods includ~ dispo~ng the carrier fil~ in the de~i~ed location, applying heat t~rough the carrler film to melt ~he ~older pr~form~, and then removing any residual water-~olu~le Adhesive (as well as any residual carrier film sub~trate, i~ ~t i~ als~ water-soluble) in a conv2ntion~1 hydrocleaning operation.
The invent~on further en~ompasses ~ethods of a83emb1ing her~atic sealing cover~ ~or a contalner hou~lng a semicon~uctor devica, ~n whlc~ th~ carrier film d~cribed hereinabova i8 utilizad in the form of two continuou~ tapes to automatq and ~peed up th~
procc~s o~ àligning a plural~ty o~ solder preforms ~ith a plurality of corresponding lid~ in an assembly-llne ~as~ion, prior to the attachment of each ~older preform to a lid, thereby lncrea~ing the y~eld o~ such ~overs, -6- -- 130~510 The~e and oeh~r ob~ec~ eatures and advan-tages of the present ~nvent~on will become more appar-~nt from th~ detalled description o~ thQ pr~erred em~odl~ents thereo~, when read ln con~unct~on wi~h the 5 drawing~, wherein:
FIG. 1 13 a per~peotivQ v~w of ~ aarrler film fabric~ted ~n ac~ordance wlth the p~e~ent invan~
tlon FIG. 2 ~3 an enlarged, cros~-sectional view~
~aken sub~tantlally along th~ line 2-2 of FIG. 1;
FIG. 3 i~ a schematic view illu~trating th~
USQ of the carrl~r ~ilm in con~unction with th~ con-~ection o~ pins to a prin~d circUit board;
FIG. 4 i~ an enlarged, cros~-s~ctional ~l~w, ta~en substantially along the line 4-4 of ~IG. 3, showing a portion of tha carrier f1lm and a solder preform ln po6ition adjacent th~ prlnted circutt board and pin, immedIately prior to the application of heat;
FIG. 5 i~ the 8ame view a~ FIG. 4, ~msdi-ately a~ter the applica~ion o~ heat;
FI~ a schematic V~RW illu~trating ~h~method of aa~mbly o~ the c~rrier filmt FI~;. 7 ls an exploded, perspective view of a sealing covHr ~or a hermetlcally s~al~d contain~r which may b~ a~sembled u~ing the carrier fllm o~ the pr~sent invention;
F~a. 8 i~ ~ chematic vlew illu~trating the a~embly proces~ ~or th~ ~over depicted in FI~. 7;
FIG. ~ is an ~nlarged plan view, taken sub-Rtantially along the l1ne 9-g of ~IG. 8; and FIB. 10 i~ a further 8nlarged, cross-sa~-t~onal view, ta~en cubstantially along th~ line 10-10 of FIG. 3.

Referrlng now ~o the drawing~, and in par-ticular to FIGS. 1 and 2, a carrier film made in ac-cordan~e Wlth the pre~ent inven~ion i~ generally de-ai~natad at 10. Carrier ~ilm 10 comprise3 a he~t-rc~is~an~ substrate 12 havinq two substantially ~lat opposed surraces 14,1~. Su~face 16 of substrate 12 i~
coated wit~ ~ wa~er-soluble pressure-sensitive adhes-iV~ 13, ~hich removably re~ains a plurallty of bodie~
~f ~eat fu~ible material on surface 16 of sub6trate 12. As shown i~ tratiYely in FIGS. 1 and 2, the bodle~ o~ heat fusible material may comprise preformed donut-~aped solder w~sher~ or rings, ~u~h a8 t~ose typically used to mak3 electrical cDnnection~ between conne~tor pins and printed CircUit boa~d~, a represen-tatlve ring being designated at 20. Generally, each solder ring 20 has a cantral hole 22 which is sized to ~it and ~lip over the item to be soldered, typically a cylindrical connector p~n. Substrate 12 ~3 provided with co~ræ~ponding generally ~ircular perforation~, a represent~tive p~oration being de~ignated at 23 ln FIGS. 1 and 2. The diame~er~ of perforations 23 are cho~en ~o aS to ~e su~stantially t~e same as that Or central hole~ 22, a~ shown mo~t cl~arly in FIG. 2.
Solder rings 20 may optional~y be coated with a s~it-abla ~lux mat~r~ a~ (no~ shown), a~ is conventional in the a~t.
Adh~sive la retains solder rings ~o in any deslred array, t~e c~n~igur2~on or pattern of which c~n be pred~termined to ma~ch the arrangement of the connector pin~ or o~her items to be ~oldered. F~
illustra~ss a typi~al albeit exemplary patt~rn, in which ~en solder rtngs 20 are arrayed in two parallel, ~p~oed-apart row~ o~ fi~e rings each. ~hese solder rlngs 20 are intended to be used to ~onnect ten con--8- 13095'0 nactor pln~ to a circuit board in a m~tching pattern, wl~h eac~ ~old~r ring 20 surrounding one of ~aid con-ne~Qr pins, as w~ll be de~cribed more ~ully hereina~-ter in connec~ion with FIG. 3.
Spaced per~orat~ons 23 o~ substratQ 12 ar~
al~o arrang~d to match th~ ~pacing o~ the i~ms to be 301dsred, And perforation~ 23 are posltioned 30 that they are di~po~ed coaxially with cen~ral holes ~2 of solder rlnga ~0, a~ ~hown b~st ln FI~. 2. The de~red pattern o~ 301der ring 20 may ~9 repsAt~d a~ regular intervals along carrier ~ilm lO, as shown in FIG. 1, ~o th~ the ~olderlng opara~ion can b~ ~onveniently repsat~d, ~or sxample, at variou~ locations on ~he same printed ~lrcuit board. It i~ to be understood, ho~ever, that the bodles o~ heat fu~lble ma~erial may ~e preformed ~nto other sh~pes ~e.g., ~quare or r~c-~angular frame~), and that they may be arranged ln oonfiguration~ or pa~torn~ othsr than that shown il-l~stra~ively in FIG. 1. Regardle~ o~ ths patt~rn or conf~gura~ion cho~en, however, 1t ls in~ended that the carri~r ~ilm 10 be plaoed over the item~ to b~ sold-ered, wl~h ~aah body o~ h~t fu~ble ~aterlal ~ur-~ound$ng or dispo~ed ad~acent to the a~ociated item to be ~older~d, aq ds~cribed in fur~h~r d~tail b~low in connection with ~IG. 3.
In the preferred e~bodiment, carrier film lO
al~o comprl~es a ralease lln~r ~4 which ls coexten6ive ~ith ~ilm lO and which 1~ r~ova~ly retained adjacent ~urface 1~ o~ ~ub~trate 12 by adhe~ive 18. Relea~e liner 24 se~ve~ to protect the bodies of heat fus~le mAt4rial whils ~t the sam~ tims facilitating the hand-ling of carrisr ~ilm lo prior to USQ. IS ~8 preferred that c:arr~er ~il~ 10, lnc:lud~ng release liner 24, b~
conf i~ured ao a strip or t;~p~3 ha~rin~ a long~tudinal dimension which su~stantially exc~d3 its tran~verse dlm~n~io~, wlth a p~r of ~ubst~ntially parallel ~p--9- ~ 130~510 p~ed edge~ along ~he longltud1nal d~men~ion. This conflguration, in which the ~trip or ~ape ~ mo~t pre~erably betw~en one and two ln~h~ wide, advantag~-ously ena~le~ carr~er fll~ lO to b~ wound onto a spool ~0 ~acll~tate it~ ~ae ~ hown in FI~. 3), with re-laa~ ltner ~4 alBo the~e~ore prevent~ng und8~ired contact betw~en ths adheslva coat 18 on the sur~ace 16 of each wound layer with the non-Adhe3~ eoat~d sur-facQ 14 o~ th~ suac~ ive wound lay~r of ca~rier f~lm 10. Relea~e liner 24 i8 pre~erably fabriqa~e~ of papsr, al~hough any material which can ~asily be pesl~d away from aub3trat4 12 (a~ shown by arrow A in FIG. l) can be used, such mater~als be~ng well-known in the art.
In order to ~unction a8 int~nded, sub~trate 12 of c~rrier f1lm lO ~u~t be capable o~ tran~portlng heat to the ~odies o~ he~t ~U~iblQ material, but at th~ ~ame tlm~ mu8~ it~lf b~ cap~ of w~t~ tanding temp2ra~ure3 a~ or ~ htly above th~ meltlng te~pera-ture o~ the heat ~usible ~aterial for at l~ast the duration o~ the solderlng proce~. Th~refor~ e pr~c~se eh~rac~ristics ~ho~en for ~ub~trate 12 will depend upo~ the n~ture of the heat fusiblQ material baing us~d.
In general, it ha~ been ~ound tha~ ~ubstrate la ~u~t be heat-re~i3tant to a te~peratu~e which 1~ at least 20~C ~bove th~ ~elt~ng point o~ the hsat ~usi~le mat~rial. I~ wlll ~ evident to thoso s~illed in th~
art that ~or a ~VQn compo~itlon o~ ~ubf3trat~3 12, the higher the melting t~mpsraturo o~ ths heat fusible material beinq u~ed, the t~cker substratQ 12 mu~t b~
in order to with~tand the h~ghe~ soldering temper~t-ure~ r~quire~. Conv~rsely, if th~ heat ~u~bl~ ~ate~-ial balng u ~d has a lower ~elt~ng ts~perature, sub-~trate 1~ may ba c~osen to ~e thinnqr. Tabla I set~
~orth se~eral 801d~r alloy~ which are commonly-used ln -lo- 1 3u~5 1 0 the semiconductor electronics industry, together with their respective melting tPmperatures or the ranges thereof, and the range of the thickness which has been found to be suitable for substrate 12.

TABLE I

MELTING SUBSTRATE
SOLDE~ ALLOY TEMPERATURE THICKNESS
52% Bi/32% Pb/16% Sn g6Oc .002-.003"
(Semalloy*1280) 60% Pb/40~ Sn 183-235~C .003-.006"
58% Bi/42% Sn 125-127C .004-.006"
80% ~u/20~ Sn 280C .006-.010l' In Table I, a range of thickn~sses for substrate 12 is given for each different solder material listed. In each case, if the soldering operation requires full soldering (i.e., complete melting of the heat fusible material), then the thickness of substrate 12 should be chosen at or near the higher end of the range given. Conversely, if the soldering operation re-quires only tack soldering (i.e., only localized melt-ing of the heat fusible material), then the thickness of substrate 12 may be chosen at or near the lower end of the range given.
In one preferred embodiment of the inven-tion, the heat fusible material out of which solder rings 20 are fabricated is Semalloy* 1280, and sub-strate 12 of carrier film 10 comprises a transparentfilm which is approximately 0.002 inches thick. A
suitable carrier film having a substrate of this de-sired thickness, and which is coated on one surface thereof with a water-soluble pressure-sensitive adhes-ive, is available with a suitable release liner in theform of a tape or ribbon from ~dhesives Research, Inc.

* Trade Mark :`~

1 3Uq51 0 of Glen Rock, Pennsylvania under the trade name Solu-mask*7242. It has been found that this product has acceptable characteristics of temperature resistance and heat transport of the substrate, as well as water S solubility of the adhesive, for use with solder rings fabricated from Alloy 1280 and intended to be used to connect a plurality of connector pins to a printed circuit board. Moreover, this product has the addi-tional characteristic that the substrate (as well as the adhesive which is coated onto it) is water-sol-uble, and it is therefore within the scope of the present invention to provide a carrier film 10 in which both the substrate 12 and the adhesive 18 are water-soluble, a term which as used herein means that the substrate and adhesive will dissolve in aqueous solutions at room temperature or higher.
In another preferred embodiment of the in-vention, substrate 12 of carrier film 10 comprises a Mylar*material which is approximately .006 inches thick, and which is available commercially from ~ent Adhesives Product Company of Kent, Ohio, or from the Electronics Materials Division of E. I. DuPont de Nemours & Company, Inc. of Wilmington, Delaware. In this embodiment, the carrier film is assembled by coating the ~ylar*substrate with a water-soluble pres-sure-sensitive adhesive which is available from the aforementioned Adhesives Research, Inc. Because of its increased thickness and chemical structure, the use of a Myla~ material for substrate 12 provides a more heat-resistant carrier film which is also non-hygroscopic and less stretchable, and for these reas-ons, this e~bodiment is preferred when using high-melting heat fusible materials such as gold~tin al-loys.
Due to its greater thickness and/or strength, the use of Mylar* as the substrate for car-* Trade Marks , -12- 13~513 rler ~llm 10 al~o allowe lnd~xing And~or ~pr~ket holes ~o be punched along ~he edge~ or the ~ when it i~ con~lgurQd a~ a tap~. Thus, oub~trate 12 of carrier ~llm 10 i8 optionally provided wlth a series of lndextng and/or ~proc~et hole~ 26 di3posed ad~acent opposeq edge~ 27A, 27~ o~ ~ubstrate 12 and runn~n~
alonq the longitudlnal dlmen~ion o~ carrier ~11~ lo (as shown illustratlvely ~ n FIG . l) . Indsxing holes 26 are adapted to ba usQd in con~unction wlth a con-vent~o~al pl~-~e~d mechanism (not shown) ~o facllitate continuoUs automatic advance~ent o~ carrier ~ilm 10 when desired.
Substrate 12 o~ carri~r ~ilm 10 may al50 be provided wi~h a plurality o~ locating hole~, a rep-resentativ~ one o~ whioh is de~ignated at 28 in FIGS.
1 and 2, the p~rpose o~ which 1~ to acco~modat~ a printed clrçult board and connector pln conflguratlon in whlch not all o~ ~h~ conn~ctor p$n~ rQquir~ ~old~r connection~. Th~ num):~er, Qpacing, 8~ Z~ and location of locating holas 28 ~ay be chosen ~o as to ~tch the pattQrn of connec~or pins for which ~old~r connection~
are not ~equ~red~ Lccatlng holes 28 enable carrler ~lm 10 to fit over such ~onnector p~ns wi~hout tear-ing. In the illustrative ~mbodi~snt ~hown in ~IG. 1, a xow Or ~ive locating hole~ 28 i~ al~po8~d on carrier ~ 10 parall~l to and sub8tantially midway between eacb p~lr of rows o~ ~older ring~ 20, but sligh~ly of ~e~ tran8versely wi~h respect to the ~older rings 20.
RR~err~ng now to FICS. 3-5 ln addition to th~ a~or6mentioned FIGS. 1 a~d 2, carrier ~1~ 10 can b~ illustr~tlvely utili2ed in tha manner sho~n in F~.
3 to ~acilitat~ the attachmen~ o~ a plurality o~ con-nQctor pins to a prlnted clrcuit board. A8 ~hown in FlG. 3, carrier fil~ lo is provided ln the rorm of a t~p~ or ribbon wound around a hub 30 to ~or~ a roll -13 1 30q 51 0 31. ~ub 3C 1~ ~ounted ~or r~tation upon A spindle 31A, and may be unwound in tha direction ~hown by ar~o~ ~ and ~hereaft~r advsn~d laterally in th~ dir-~ctlon shown by arrow C. Immadlat~ly prior to u~e, ~elea~e lin~r 24 o~ carrler ~ilm 10 iA peeled bac~, and may be at~ch~d ~o and wound ln th~ directlon 6hown by arrow D around a hub 32 mount~d for rotation upon a sp~ndl~ 33A to for~ ~ r~lea~ liner roll 33 w~ch ~ay ~e di~ard~d or pr~s~r~ed ~or subsequent re-u~e.
A8 shown in phantom line~ ln FIG. 3, ~ub-strate 12, wlth ~older rlngs 20 dispo~ed and retalned on the lower sur~aae th~reof ~y means o~ adhe6i~ 18, iB ini~lally dl~posed above and ad~acsnt an array of connector pin~ 34,35 which have b*en prepo~ltioned ~n a prlnt~d clrcuit boa~d 36 which res~s on a 3uppor~ing me~ber 37. It 6hould be unders~ood tha~ in th~ illu~
tr~ivQ configuration depicted ln FIG. 3, each of connector p~ns 34 ~ intendad to rec~ive a sold~r ring 20, whila each of conn~ctor pin~ 35 i~ lntended not to recsive a solde~ ring 20. Wh~le conn~ctor pin~ 35 are ~how~ a~ being 3ho~er than conn~ctor ptn~ 34, it should be under~tood that thi3 is ~or purpo~s o~
illustration only, and that connector p~ns 35 may 4e th~ e l~ngth as, or ~onger than, ~onnector pins 34.
It ~hould also be understood that FIG. 3 i8 an edge view, and thzlt b~hlnd eaah o~ connector pins 34,35 dep~cted ln FI~. 3 are four add1t~onal identical con-ne~tor pins ext~ndlng in a parallel row below th~
plan~ o~ th8 drawing, non~ of wh~ch are vi~ible in FI~. 3.
A~ shown more clearly in FIG. 4, each of conn~ctor pln~ 34 ~s 1003ely supported in print~d clr~u~t board 36 prior to th~ 601d~ring operat~on by mean~ o~ a receivlng hol~ 38, a plural~ty o~ which are provldQd in a patt~rn corre~ponding to the patt~rn of conne~or pin~ 34 whic~ r~qulr~ otrlcal connection to print~d cir~ui~ ~oarR 3G. It 1~ to ~ und~rstood that conneator plns ~5 may al~o be supported i~ prin-~ed oircuit boara 36 by ~an~ o~ 31mllar re~ ing holes (not ~hown).
Af~r carri~r ~il~ 10 18 posit~on~d above connQctor pin~ 34,35, carrier ~11~ lo ~ th~n moved down~ardly toward conn~ctor pln~ 34,35 (in the dlrec-tion shown by Arrow E in FIG. 3), such that locat~ng holes 28 ~lt around connactor pins 35 and ~old3r rings 20 simultaneously flt over and around oonnector pin~
34, w$th connector pin8 34 pas~ing through the aentral hole~ 2~ of ~older rlng~ 20 as w~ll a~ throuqh perfor-atlons 23 i~ 4ubstrats 12, untll ~older rln~s 20 abut the ~urfaca o~ prlnted circul~ board 35 and are ad~ac-ent receiving holes 38, as shown ln solid lines in FI~. 3 and a6 shown in further detall ln FI~. 4. At thls point, tho edges of ~ub~trate 12 surrounding conn~ctor pin~ 34 may be pre~s~d against printed cir-cuit board 36 so tha~ adhesiv~ 18 conta~s the surfaceof prin~ed ~ircuit board 36 and thereby retains car-~ier fil~ 10 and th~ solder rinq~ 20 d~po~od ther~on in the desir~d lo~ation and con~iguratlon until the ~oldering operation takes pla~a.
A~ ~hown in FIG. 4, h~t may then b~ applied by any suitable mQan3, all o~ wh~ch are conventional an~ ~ro well ~nown in the art. FI~. 4 ill~Srate~
~chema~l~ally th~ use o~ a haating tool 39, which may ta~e the ~or~ o~ an infrared hot shoe, a hot alr gun or lamp, or an RF ~r~quency lmpul~e hea~r. It i8 to b~ und~r~tood, how~v~r, that th~ soldering opera~lon can be ~ccompli~hed ~n an alternative manner, such as by h~atin~ ths entirQ prlnt~d circuit board ~n an oven or belt ~urn~ae. Although the present inv~ntlon con-templa~Qs the use of any one of th~ foregoing type~ ofh~at ~ources,. lt should bs under~tood tha~ ~f a h~at 130~510 ~o~rc~ i~ cho~en wh~ch reguire~ direa~ phy~ical con-tact b~tween ths heating ~lement and ~ub~trate 12 of carrior fll~ 10 (e.g., if an infr~red hot ~hoe i8 used as shown s¢he~a~lcally in FIG~ 4), t~n the ~hicknes~
of s~bs~rate 12 chould ~e choaen ~o a~ to be thick~r than would oth~rwis~ be r~quired i~ a non-contaot heat soUrce t~uch as an ov~n) w~re to be u~d under the ~ condltion~ ., uslng ~he same heat fu~lble matRrial ) .
As shown in FIG. 5, the Appllcat~on of h~at ~t the approp~lat~ ~mperflture ~which is ~t or abou~
the molting tempQrature of the heat ~u~ible material, and ~hich in any ev~nt ~8 well known to those skilled in the art) cau~e~ each ~older ring 20 to melt 80 that a portion 40 o~ the heat ~u~lble matsrial ~lows be-tween each connQctor pin 34 and the corre~pond~nq rQc~ving hol~ 38 in print~d circuit board ~6, with the balance 42 o~ ~he heat fu~ible m~terlal remain~ng on the ~urfac~ o~ printed circult board 36 and sur-roundlng connector pin 34. An electrlcal and~or ~ech-anical ~onnectlon batwe~n thR connector pin~ 34 and th~ prlnted c~rcuit tnot ~hown) et~hed on print~d circUit ~oard 36 about each recelving hole 38 i~
thereby created.
Th~ appropriats dur~tion for th~ applicatlon o~ heat must b~ chosen such that lt endurQ~ until ~U8 be~oro th~ carrier fllm deforms and begins to ~hrin~
ThiR dtlration will vary dependlng upon several f ~c-tors, such a~ the nature o~ the heating ~ource which is to be us~d, and ~n some ca~es the thic~nes of th~
carr~er ~ subs~rato being used. For example, it has be~n d~erm~ned that if the heat ~ource i3 chO8en to be an in~rared hot ~hoe, as illustrated schematlc-ally in ~IG. 4, and ~ th~ temp~ra ur~ o~ thQ hot shoe i9 ~et at about 5'C above the mel~ing tempexa~ur~ of th~ heat ~uslble ~ate~lal ~as i5 gener~lly pr~erred), l3a~sl0 then the optimal duration for the application of heat is approximately six seconds if the preferred embodi-ment of the present invention is used in which the carrier film is fabricated of Solumask*7242, as de-scribed hereinabove, and is approximately eleven sec-onds if the preferred embodiment of the invention is used in which the carrier film substrate is not water-soluble and is fabricated of Mylar*, as also described hereinabove. In either case, the hot shoe is prefer-ably applied with light pressure, e.g., at approxi-mately 20 pounds per square inch of carrier film, provided that no more than half of each square inch of carrier film is covered by heat fusible material.
On the other hand, if a typical non-contact heat source such as a convection oven is to be used, and if the desired oven temperature is pre-set at or about the melting temperature of the heat fusible material (as is generally preferred), then it has been determined that regardless of the thickness of the carrier fil~ substrate being used, the optimal dura-tion for the application of heat substantially corres-ponds to the heating cycle of the oven, i.e., the time it normally takes for the oven temperature to rise from room temperature to the desired pre-set temper-ature and to fall back again to room temperature,assuming that the oven is shut off immediately upon reaching the deæired pre-set temperature.
Due to the heat-resistant characteristics of carrier film 10, residual amounts of substrate 12 and adhesive 18 remain in the vicinity of each connector pin 34 after the application of heat, as shown in phantom lines in FIG. 5 and designated at 44. How-ever, a conventional hot aqueous bath can thereafter be used to remove completely any residual water-soluble adhesive, and will also remove any residualsubstrate if that substrate is also water-soluble, in -17- 130)~,19 accordance with one of the preferred embodiments of the present invention as described hereinabove. If, on the other hand, the substrate is non-water-soluble, in accordanqe with another preferred embodiment o~ the invention as described above, a hot aqueous bath can still be used to dissolve and thereby remove any re-sidual adhesive, after which the residual substrate may then be removed by peeling and discarded.
With the embodiment of the present invention utilizing Solumask* 7242, in which the carrier film substrate and the adhesive are both water-soluble, the hot aqueous bath is preferably carried out using a detergent solution in which the temperature of the water is maintained at between 90F and 180F, and in which the detergent is biodegradable and incorporates both a wetting agent and no more than approximately 7.3% phosphorous by weiqht. A suitable detergent is available commercially from Alconox Inc. of New York, New York, under the trade name Alconox* and a suitable detergent solution comprises between 0.7~ and 1.1 ounces of Alconox*detergent per qallon of water, the water preferably being of electronic grade (i.e., grade E-lll or better).
This detergent solution is preferably ap-plied to the assembled electronic components carryingthe residual substrate and adhesive, either by manual agitation or most preferably using a mechanical washer capable of spray circulation, for 2-5 minutes. The detergent solution is thereafter removed, and a clean warm or hot water rinse is then applied, also for 2 5 minutss, followed by a second rinse for 1-2 minutes, both rinses also being applied either by manual agita-tion or preferably by mechanical spray circulation.
Thereafter~ the assemblage may be heated for drying using hot air maintained at a temperature which is no higher than the highest temperature which can be tol-* Trade Marks erated by the assembled electronic components.
A similar aqueous bathing operation, using the same preferred detergent solution, may be utilized to remove any water-soluble adhesive remaining after the soldering operation is performed with the pre-ferred embodiment of the present invention in which the carrier film substrate is not water-soluble and is fabricated of Mylar* In this case, however, the as-sembled electronic components may be fragile, and rather than applying the detergent solution ~y manual agitation or by mechanical spray circulation, the electronic components are preferably subjected to ultrasonic agitation in an aqueous bath in order to remove both the residual adhesive and any residual Mylar* substrate, following which the components are blow-dried using hot air at approximately 110F.
For some applications, the use of a conven-tional hot aqueous bath following the soldering opera-tion may be undesirable and/or deleterious to the electronic components involved. It has been deter-mined, however, that the water-soluble adhesive used in all of the carrier films of the present invention, as well as the carrier film substrate of the embodi-ment of the invention utilizing Solumask* 7242, can also be dissolved in and completely removed using certain non-aqueous solubilizing agents. In partic-ular, it h~s been found that propylene glycol mono-ethyl ether, available from Union Carbide Corporation of Moorestown, New Jersey, under the trade name Propa-sol Sclvent M*, as well as vinyl 2-ethylhexyl ether (2), available from the Chemical Division of BASF Inc.
of Parsippany, New Jersey, are acceptable and effec-tive alternative solubilizing agents for use with the present invention. Either one of these solvents may be applied at room temperature by submerging the as-sembled electronic components in a container of either * Trade Marks -19- ~ J q s ~ o liquid for approximately three minutes, followed by submerging them in 1,1,1, trichloroethane for approxi-mately one minute, followed by submerging them for thirty seconds in a ~reon and methylene chloride mix-ture, such as that commercially available from theGenesolv/Baron-Blakeslee Division of Allied-Signal Inc. of Parsippany, New Jersey, under the trade name Genesolv DM. The components are then blow-dried using hot air at approximately llO-F.
It will be appreciated by those skilled in the art that the water-soluble adhesive, which is an essential component of the carrier film of the present invention, not only retains the bodies of heat fusible material in a fixed array, pattern, or configuration on the carrier film substrate prior to the soldering operation, but also leaves no residue and requires no special removal procedure other than an aqueous bath at conventional hydrocleaning temperatures. It will also be appreciated by those skilled in the art that neither the adhesive nor the carrier film substrate will degrade at conventional soldering temperatures and both are capable of transferring heat quickly to the bodies of heat fusible material, and that these are also essential components of the carrier film of the present invention.
In the embodiment of the present invention utilizing Solumas~ 7242, in which the carrier film substrate and the adhesive are both water-soluble, additional advantages are obtained. Specifically, the water solubility of the substrate enables the user to deform and mold the carrier film into non-linear shapes (including, e.g., acute and right angles) prior to the soldering operation, in order to match or con-form the carrier film to the shape of the components to be soldered. This deformation can be accomplished manually, merely by bending the carrier film, but is -20- - 1 3 ~"J5l 0 preferably facilitated by the application of a small amount of moisture to the substrate in order to make the carrier film more pliable. The embodiment of the present invention, in which the carrier film substrate is not water-soluble and is fabricated of Mylar* can be similarly deformed by the user, provided it is pre-perforated in an appropriate manner to create the necessary flexibility.
A further advantage which is obtained with lo the embodiment of the present invention utilizing Solumask*7242 relates to the use of solder flux. If solder rings 20 are optionally pre-coated with a flux material, then residue 44 (shown in FIG. 5~ may also include a quantity of unused flux. As is well known in the art, any residual flux remaining after the soldering operation must be removed, and the removal operation can conventionally be facilitated either by using only water-soluble fluxes, or by mixing water-soluble fluxes with conventional non-water-soluble fluxes, thereby permitting the fluxes to be washed away in an aqueous bath after the soldering operation is complete.
It has been found that the embodiment of the present invention utilizing the Solumask*7242 product of Adhesives Research, Inc. further facilitates this operation by permitting incorporation of a water-sol-uble flux directly into the water-soluble substrate, and therefore provides an advantageous facility for introducing a water-soluble flux into the soldering operation. Using a vehicle such as methylethylketone ( or any non-miscible al¢ohol such a~ anhydrous isopro-pyl alcohol), one or more water-soluble fluxes can be transferred to the carrier film 10 by any suitable coatinq process.
3s An example of a water-soluble flux which is available in liquid form and which can be incorporated .~ ~

-21- -- l 3~510 into the carrier film 10 of the present invention in the manner described is water-soluble Organic Flux 2331, available from the Xester Solder Division of Litton Industries of Chicago, Illinois. This flux material can be applied either by dissolving it into methylethylketone to form a 50/50 solution by volume, or by dissolving it in anhydrous isopropyl alcohol to form a solution which is 75% alcohol by volume (the latter solution being the one preferred). In either case the solution is lightly wiped onto the adhesive-coated surface of the carrier film substrate in the vicinity of the solder preforms, and/or onto the sol-der preforms themselves, using a con~entional syn-thetic cellulose sponge, and is then allowed to dry in air.
It has also been found that the heat resis-tant characteristics of a carrier film fabricated according to the embodiment of the present invention which utilizes Solumask*724~ can be effectively in-creased by spreading cornstarchj dissolved either inanhydrous isopropyl alcohol or in water, onto the water-soluble substrate prior to use, thereby increas-ing its effective density. This can be accomplished either by dissolving 6 ounces of a commercial grade baking cornstarch in 32 ounces of anhydrous isopropyl alcohol, or by dissolving 4-~ ounces of such corn-starch in 30 milliliters of water, to form a solution which in either case is then wiped onto the substrate using a conventional synthetic cellulose sponge and then dried using an infrared heat lamp at approxi-mately 80~F for approximately one and one-half minutes until dry.
Although the aqueous cornstarch solution has been found to be more effective than the alcoholic solution, the agueous solution is at the same time more dif f icult to apply because the water-soluble -- 130~510 substrate will dissolve if excessive amounts of the aqueous cornstarch solution are applied. This effect can be avoided by observing the color of the substrate during the wiping operation, and by terminating the application of the aqueous cornstarch solution after the substrate becomes slightly milky in colcr. While the use of the alcoholic cornstarch solution will eliminate this undesirable solubilization of the sub-strate, the alcoholic solution is less effective in increasing the effective density of the substrate.
In either case, the use of cornstarch in this manner enables the carrier film to withstand higher soldering temperatures without degrading, and therefore enables the use of higher-melting heat fus-ible materials than would otherwise be possible for agiven thickness of the carrier film substrate~ For example, although the Solumask*7242 product is norm-ally not usable with heat fusible materials having melting temperatures higher than about 255~C, the incorporation of cornstarch in the manner described above permits this embodiment of the invention to be used with higher-melting heat fusible materials, hav-ing melting temperatures as high as 290C.
It has been found that the heat-resistant characteristics of a carrier film fabricated in accor-dance with the embodiment of the present invention which utilizes Solumas~ 7242 can also be effectively raised by dissolving nitrocellulose into the carrier film substrate, using methylethylketone or anhydrous isopropyl alcohol as a vehicle and thinner for the nitrocellulose. This method is preferred over the use of cornstarch as described above, and is most effec-tive if pure nitrocellulose, available from Stan-Chem Incorporated of East Berlin, Connecticut, is used.
The incorporation of ni~rocellulose can be accom-plished either by combining one-half ounce of pure -23- -- 130q510 nitrocellulo~e ~or ov~ to-an ouncd~ of m~thyl-ethylk~one~, or by combinlng ono-half` ounce o~ pure ni~roc:~llulo~ ~or every ten ounc~ o~ anhydrous ~ ~o-pr~pyl al¢ohol ~ to form ~ ~olutlon wl~loh in ~ith~r ca~o i~ wip~d onto the carrl~r f llm ~ rato u~lng a conventional E~yr~thc~tlc cellulo~s sponge and ~ then allowlad to dry 1 n air. It has been ~ound that when methylethylketon~ i~ u~d ~ the veh~cle and thinner ~or the nitrocellulo~a, the ~ir drying operation con-sum~ time than wh~n anhydrous isopropyl alcohol i8 U8Qd, and there~ore th~ u~e of ~ethylethylX~tone p~e~erred.
Although ni roc~llulo~ i8 not usually w~t-er~solubl~, it has b~en found th~t whon incorporat~d ~5 into ~he carrisr $1lm of ths pr~Bent invention ln thQ
~anner dQgarlbed~ any ra~dual nitrocellulo6e remain-ing a~te~ the ~old~ring operation 15 compl~ can ~e d~ssolv~d an~ thereby ramov~d in A conventional hot aqueou~ ba~h.
A carrl~r fllm accordlng to the prs~ent invent~on can be ass~mbled in a mannor Whi¢h is dep~c-tod ~ch~matlcally ln FIG. 6. In par~cula~, ~ supply roll 46 o~ the c~rrl~3r film to be usQd (e.g., Solumas~
7242 ) i~ mount~ or rotation on a spindlQ 47 . A5 ~oll 46 unwind~ ~n the d~rection ~hown by ar~ow F~ th~
rsl~lasa liner 24 i~ pe~led back ~rom substrate 12, and ~ tra~nsd ~bout pul~ey~ 48 for transport in thQ dl-rectlon ~hown by arrt)w G and ev~n~u~l reunlon with ~ub~trate 1~. Tna latter, w~th adhe~lvo ~8 coated or, o~le ~urfacs 16 thereof, 15 trained about pullay~ 4~, and p~Q~ through a di~ 50. A ~ourc~ ~not ~hotrn) of bodies o~ a~ fu~ibl~ ma~ar$zll, such a~ preformsd ~old~r rln~s 20, ls located ad~cent die So, which may ~e operatad slth~r manually or ~n an auto~atad ~ashion to affix solder rlngs 20 ~o ths ~dhe~ivOE-co~ted r~ur-~ace o~ tra~ 12 ~ n the deslred pa~tern or con~ig~

-24- . ~ 3 G!~ 51 0 ~ratlon, while at tha ~am~ ti~ c~eAt~ng perforations 23 ~hown b~t ln FIG. 2) in ~lignme~t with the cen-trAl hol~a 22 Or sold~r ring~ 20.
~t~r sub~trat~ 12 p~s~e~ throu~h tho dle, a~ ~own in FIG. 6 rel~A~e lln~r ~.4 i~ th~rea~ter re-~o~ned wit~ substrate 12, by r~ttachlng t~Q rel~ase lln~r 24 to ths surface 16 of sub~trate 12 carrying adhesiv~ 18, ollow~ng wh~ch the a~se~bled carr$er film 10 1~ wound onto a tak~-up roll 52 wh~ch is moun-ted ~or rQtation on ~pindl~ 53 in th~ di~ection ~hown by arrow H. It in contemplats~ t~at the a~aem~ly pro-ce~ur~ deploted schs~atically ln FIG. 5 can be auto~a-ted, in which ca~e ~pln~le 53 WOUld b~ appropriately connect~d to and driven by driva ~an~ ~not shown) which would al~o act or cooperat~ in a known mannsr with rec~procatinq ~ean~ (not shown) to close the ~ating hal~es SOA, 50B o~ di~ ~0 at appropriat~ inter-vals.
Re~erring now to FIGS. 7-10, a ~thod of fa~ricatln~ ~ condu~lve h~r~etlc ~0al~ng cover for a conta~nQr hou~ing a ~emicon~uctor d~vic~, using th~
carrler 2ilm of th~ pres0nt lnvQntion, is illustrated thore~n. A~ ~hown in FIG. ~, a conventional conduc-t~ hermetic ~ealln~ cover, gen~rally des~gnated at 54, comprlse~ a ~lat me~allic lid 55 and a pre$o~med ring or ~ram~ 58 ~hich is fabrlcated of a heat ~usible materi~l and whtch i8 supe~impose~ upon and at~ached ~o th~ lid 56 in registry with the perlph~ry thereo~
As ~ot ~orth h~elnabove~ ~ch s~alln~ cover3 are - 30 ~yplcally u~ed to s~al tha cavity o~ ~ semiconductor packag~ which ~ay co~tal~ ~n ~atl~e $nt~gratQd-circuit 3ili¢0n chlp. For most applicatlons, the lid 56 ~
~abri~at~d of a nlck~l-cobalt-lron alloy, widely mar-X~ted undsr the trade name KOVAR, w~ic~ i~ subse qusntly gold-platsdr and in ~a~y appl1cation~, the fram~ ~8 o~ hea~ ~u~ible material co~pr~s~s a gold-tin - 130~510 eutectic solder, although other solder alloys such as lead-tin are also sometimes used. The sealing cover 54 is typically provided as a unit, with the solder frame 58 pre-attached to the periphery of the lid 56 by heating the frame to a fusing temperature at a plurality of spaced points (e.g., at the four corners) in a spot welding operation which typically requires that the frames and lids be manually fed into the attachment apparatus.
The carrier film of the present invention can be advantageously utilized to automate the previ-ously described assembly process, as shown schematic-ally in FIG. 8. A plurality of solder frames 58 are mounted sequentially on a dispensing tape 60 which is fabricated in accordance with one of the preferred embodiments of the present invention described above, in which the carrier film substrate is not water-soluble and is fabricated of Mylar*which is approxi-mately .006 inches thick. The dispensing tape 60 carrying frames 58 is wound onto a supply roll 62 from whieh a release liner 64 is peeled back as supply roll 62 is unwound in the direction shown by arrow J, thereby exposing the adhesive-coated surface 68 of tape substrate 66 on which frames 58 are disposed.
Similarly, a plurality of lids 56 are mounted sequen-tially along a second dispensing tapa 70, also fabri-cated in ac:cordance with the same embodiment of the present invention. The dispensing tape 70 carrying lids 56 is wound onto a supply roll 72, from which a release liner 74 is peeled back as supply roll 72 is unwound in the direction shown by arrow K, thereby exposing the adhesive-coated surface 78 of tape sub-strate 76 on which lids 56 are disposed.
By means of an appropriate roller and/or pulley arrangement (includinq, for example, roller 79 in FIG. 8), the adhesive-coa~ed surface 68 of dispen-- 1 30~51 0 sing tap~ fio i~ the~l brought into ~ac~ng r~lation wlth tho adhesivo coat~d sur~c~ 78 o~ dlap~n~ing tap~ 70, such tha~ each ~rama 58 mou~t~d on dl~pen~lng taps 60 i~ ~lspo3ed ad~scent ~o and i8 sup~rimpOsQd upon a Corre~ponding lld ~6 mounted on dispensing tape 70, wit~ each f~am~ 58 in regi~try with ~ha periphery o~
th~ correapond~ng lid 56, as shown b~t in FIG~. g and 10 .
~h~le malnt~ning th~s facing relatlon~hip, 1~ di3pQnsing tape~ 60 and 70 ~re pa~s~d through a tuck-ing ~ean~, ~hown lllustratively in F~G. 8 aR comprie-~ng flnger~ 80A, 80~. PrQ~ar~bly, flnger 80A r~ma~n~
stationary, whil~ flnger AOB r~clprocat4~ ~n the d~r-ection shown by arrow ~ between an active po~it~on (shown in FIG. 8) in whi¢h one end 80C $B in Cont~ct wlth sUbstra~e 76 o~ disp~nsing ~ap~ 70, and an lnac-tive po~itlon (not ~hown) in which it is out o~ ~on-~act with ~ub~tra~ 76 o~ dispensing tape 70. The end portion 80C of ~inger ~OB 18 generally arcuata in sh~pe, and ~inger 80B i9 drlven repetitively $nto and out of contact wit~ ~ub3trate 76 ~y re¢lprocat$ng ox cam ~ean~ ~not shown), with the interval batween ~uc-ceJ~ive r~c~procations o~ f~nger 80B be~ng cho~en such that said contact occurs only in the areas betwean su~ce~ e lld8 56 mount~d on di~pens~ng tapo 70.
A~ b~3t shown in FIG. 10, each ~ucces~ve reclp~ocat~on o~ ~inger 80B urg~ ~ub~t~ate ?6 of d~Bpensing tupe 70 towarda ~ub8trate 66 o~ dispen8$n~
tape 60l 8U~h that the adhe~ive-coa~ed ~ur~ace 78 of d~pon~ng tape 70 contact~ the adhe~lv~-coat~d ~ur-~ace 68 o~ dispen~ng tape 60, ~orming a tuck or r~-c~s~ 81 in ~ 8t~at~ 76 of di~penslng tap~ 70, wh~ch pro~r~bly ext~nds tran~vQrssly ~ro~ o~e edge of sub-strat~ 76 to.the oth~r ed~e. The contact between th~
w~ter-601uble adh~slve coate~ on ~urface 68 o~ sub~
8trate 66 and the w~ter-801uble adh~lvo coatad on surfac~ 78 o~ su~S~rate 7~ wh1ch ~orm3 recesses 81 i~
su~icient to flx ~he po~lon~ of each ~ucces~ive l~d/fram~ p~ir euch that th~ regi~tration of each ~rame 56 with the periph~ry of the as~oclat~d lid S6 5 i8 malntained prlor to ~nd during the ~ub~eguent a~-tachment ~t~p.
In this con~iguration, the di~pensing ~apes 60,70 are advanced ~oward~ an attachment means, whlch ~llu~trat$vsly comprises a ~pot wslding apparatu~
dep~cted ~chem~tic~lly at 82 in FIa~ 8. Such spot welding appar~tu~ are well known in the art, and typ-ically comprise a w~lding head 84 d~spo~e~ abo~e a support~ng me~b~r 85, one ~uch apparatu~ being de-scribed ln detail in U.S. Patent No. 3,946,1~0. It will b~ understood by thQs~ ~k~lled in th~ art that the conventlonal 5pot welding ope~ation can take pl~ce despite the ~ac~ that ~ubstrate 66 of dispen~n~ t~pe 60 prevent~ dlrect contac~ between thQ welding elec-trGdes (not shown) of the weldlng h~ad 84 and each ~uc¢essive frame 58, dus to ~h~ heat transpor~ and heat resistant characteristic o~ the dlspen~ing tape 60 as de~cribed hereinabove.
T~e attachment operation result~ in an e~-~ect~ve at~Achment b~twean each lld 56 and the ~or-responding frame ~8, ~oxm~ng a~seFbled covers de~ig-nat~d at 86 in FI~. 8. Thereafter, the dispensing tap~ 70 is paF.6Qd throu~h str~pping means, repre8ented w hematically ln FIG. 8 by roller 87, which effects xemoval o~ ~ubstrate 76 ~ro~ the a ~embled covers 86, a~ter which ~ubstrat~ 7~ may be discarded or recycle~
~or 3u~8~quant U5~. Substrat~ ~6, on which ~he ~s~e~-bled covers 86 remain di~posed, i~ then re~oin~d with a r~l~a~ linqr 88, and i~ wound in th~ ~irection of arrow L on a take-up roll so. T~e a~sem~led coverq 86 3S may b~ pro~ided in thls form, or may alternativ~ly be removed fro~ th~ tap~. and r~packagad, ~3r subsequen~

130"510 U8~ in ~ h~rme~lc se~lln~ vperatlon to cover a con-tainer hou~ing a ~emiconductor devi~e.
I~ de~ired, the residual water-solubl~ adhe-sive remalning on th~ ~ur~aco 89 o~ each as~em~led cover 8~ that was previously ln contact wlth ths adhe-siv~-coated ~ur~a~ 78 of ~ub~tr~t~ 76 ean be removed by pa~ing ~ wa~r-impregnat~d hard ~pon~e ove~ each ~urface 89, either prior to ~h~ r~oining of relea~
liner 88, or ln a 3ub~equsnt sep~rate r~n~ng opera-10 tion. }~owev~r, lt has b~r, discovered that the re~id-ual adheslve can ~erv~ as A watting agent, which will ~acilitate th~ creatlon of a hermetic ~eal when the a~embled ~overs 86 ~rs su~e~u~ntly u~ed to saal a container housing a ~emicondu~or device. Therefors, ~t 1~ within the scope of this embod~mont of th~ in-vention that th~ step of removlng any residual adhes-iv~ be omitted.
As shown in ~IG. 9, e~thsr or both of di~-pens~ng tapes 60,70 can b~ provided optionally with ~pr w ket holes ~2 located ad~acent the oppo ed paral-lel Edges 94A,94~ o~ ths tape (8) and running along the longitudlnal di~Qnsion th~reo~. ~he ~pro~ket hol4s 92 ars adaptad ~o cooperata with ~onventional pln ~e~d means (not shown) to ~dvanc~ th~ di3pen6ing tape~ and 2~ ~er~y auto~at~ still ~urther tho fabricating ~e~hod o~ the inventlon.
Whlle there has besn descri~ed what are, at pre~nt, con~ldered to b~ th~ pre~erred embodimQnt~ of the invBnt~ on, it will be obviou~ to those sklllQd in th~ art th~t v~riou~ ohanges and modi~lcations ~ay be mada therain, wlthout depar~ing ~rom the ln~ention, and it ls, there~or~, almed in the appended claim~ to cov~r all such change~ and mcd~fication~ ae fall with-in the tru~ spirit and scope of the invention.

Claims (15)

1. A carrier film for transporting and dispensing a plurality of bodies of heat fusible ma-terial, said film comprising a heat-resistant sub-strate having two substantially flat opposed surfaces, and a water-soluble adhesive coated on one of said surfaces for removably retaining said bodies on said film.

2. A carrier film according to claim 1 further comprising a removable liner coextensive with said film and releasably retained by said adhesive adjacent the adhesive-coated surface of said sub-strate.

3. A carrier film according to claim 2 wherein said bodies of heat fusible material comprise pre-formed solder rings.

4. A carrier film according to claim 3 wherein said solder rings are disposed on said film in a predetermined pattern.

5. A carrier film according to claim 4 wherein said film is perforated in a predetermined pattern corresponding to the predetermined pattern of said solder rings, whereby said perforations are aligned with the central holes of said rings.

6. A carrier film according to claim 5 wherein said film is configured in the form of a strip having a transverse dimension, a longitudinal dimen-sion which is substantially greater than said trans-verse dimension and a pair of substantially parallel opposed edges along said longitudinal dimension.

7. A carrier film according to claim 6 wherein said predetermined pattern of solder rings is repeated along the longitudinal dimension of said strip.

8. A carrier film according to claim 7 wherein said substrate is water-soluble.

9. A carrier film according to claim 7 further comprising means for advancing said strip in a direction parallel to its longitudinal dimension.

10. A method for simultaneously connecting a plurality of components to a printed circuit board having a plurality of apertures adapted to receive said components in a predetermined pattern, said mat-hod comprising the steps of:
(1) arranging said components within said apertures, (2) disposing adjacent said apertures and adjacent said components a carrier film comprising a heat-resistant substrate, a water-soluble adhesive coated on one surface of said sub-strate, and a plurality of bodies of heat fusible material retained by said adhesive on said film in a pre-determined pattern corresponding to the predetermined pattern of said apertures, (3) retaining said carrier film in place by contacting said adhesive with said printed circuit board, (4) heating said carrier film above the melting point of said heat fusible material, and (5) washing said printed circuit beard in an aqueous bath to dissolve and re-move said adhesive.

11. The method of claim 10 wherein said heat-resistant substrate is water-soluble and wherein said washing step also includes dissolving and remov-ing said substrate.

12. The method of claim 11 wherein said plurality of components comprises a plurality of cyl-indrical pins.

13. The method of claim 12 wherein said bodies of heat fusible material comprise pre-formed circular solder ring, wherein said carrier film is perforated in a predetermined pattern corresponding to the predetermined pattern of said rings such that said perforations are substantially circular and are aligned with the central holes of said rings, wherein the diameters of said circular perforations and the diameters of said central holes are slightly larger than the diameter of said pins, and wherein said disposing step comprises placing said carrier film over said pins such that said rings are disposed cir-cumferentially around said pins.

14. A method of dispensing a plurality of bodies of heat fusible material in a predetermined pattern on a workpiece, said method comprising the steps of:
(1) affixing said plurality of bodies in said predetermined pattern to a car-rier film comprising a heat-resistant substrate coated on one surface thereof with a water-soluble adhes-ive, (2) transporting said carrier film to the location at which said bodies are to be used, (3) retaining said carrier film in said location by contacting said adhesive with said workpiece, (4) heating said carrier film above the melting point of said heat fusible material, and (5) washing said workpiece to dissolve and remove said adhesive.

15. A method of fabricating a plurality of sealing covers for a container comprising:
(1) providing a first continuous dispens-ing tape having a water-soluble ad-hesive coated on one surface thereof for retaining a plurality of pre-formed rings of heat fusible material thereon;
(2) providing a second continuous dispen-sing tape having a water-soluble adhesive coated on one surfaced there-of for retaining a plurality of pre-formed covers thereon;
(3) advancing said first and second tapes towards an attachment means while maintaining said adhesive-coated surface of said first tape adjacent to and in facing relation with said adhesive-coated surface of said sec-ond tape such that each of said rings is maintained adjacent to and is superimposed upon one of said covers in registry with the periphery there-of;
(4) contacting the adhesive-coated sur-face of said first tape between adja-cent rings with the adhesive-coated surface of said second tape between adjacent covers;
(5) passing said first and second tapes through said attachment means to produce an effective attachment be-tween each said ring and the corres-ponding cover;
(6) removing said second dispensing tape;
and (7) collecting the attached cover-sealing ring units on said first dispensing tape.