CA1042116A - Heat recoverable cap - Google Patents
Heat recoverable capInfo
- Publication number
- CA1042116A CA1042116A CA215,092A CA215092A CA1042116A CA 1042116 A CA1042116 A CA 1042116A CA 215092 A CA215092 A CA 215092A CA 1042116 A CA1042116 A CA 1042116A
- Authority
- CA
- Canada
- Prior art keywords
- sealing member
- package
- substrate
- wall
- sealing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/02—Containers; Seals
- H01L23/04—Containers; Seals characterised by the shape of the container or parts, e.g. caps, walls
- H01L23/053—Containers; Seals characterised by the shape of the container or parts, e.g. caps, walls the container being a hollow construction and having an insulating or insulated base as a mounting for the semiconductor body
- H01L23/057—Containers; Seals characterised by the shape of the container or parts, e.g. caps, walls the container being a hollow construction and having an insulating or insulated base as a mounting for the semiconductor body the leads being parallel to the base
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/02—Containers; Seals
- H01L23/04—Containers; Seals characterised by the shape of the container or parts, e.g. caps, walls
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/0001—Technical content checked by a classifier
- H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/01—Chemical elements
- H01L2924/01079—Gold [Au]
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/095—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00 with a principal constituent of the material being a combination of two or more materials provided in the groups H01L2924/013 - H01L2924/0715
- H01L2924/097—Glass-ceramics, e.g. devitrified glass
- H01L2924/09701—Low temperature co-fired ceramic [LTCC]
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Abstract
ABSTRACT
A method of sealing electrical components by positioning over the electrical component a heat recoverable sealing member. When a metal sealing member is utilized, the metal is in a deformed, unstable martensitic state, and thereafter is allowed to heat recover to a stable, austenitic state. When a plastic material is used, the polymer is heated, deformed and quenched in an unstable state, so upon heating it recovers via its elastic memory to a stable state.
A method of sealing electrical components by positioning over the electrical component a heat recoverable sealing member. When a metal sealing member is utilized, the metal is in a deformed, unstable martensitic state, and thereafter is allowed to heat recover to a stable, austenitic state. When a plastic material is used, the polymer is heated, deformed and quenched in an unstable state, so upon heating it recovers via its elastic memory to a stable state.
Description
104'~
~his i~vention relates to the ~ealing oi electrical components.
It i~ frequently important, and sometime~ critical, that electricsl components should be sealed ~rom the atmosphere to prevent their contamination and deterioration. The sealing o~ electrical components is especially important in the ~ield oi semiconductor packaging where the microcircuitry oi a #emi-conductor chip iæ extremely su~ceptible to iailure. The size of the circuitry on such miniature components i8 often oi the order oi microns and the~ are readily subJect to short or open failure upon e~posure to the environment. In addition to failure o~ the connective circuitry, atmospheric contamination oi the semiconductor material itseli may drastically affect its electrical response.
~uch components are ~requently ~ealed and protected irom the atmosphere by iusing a glass layer over them.
Alternatively, a metal cap may be used, ior example, by soldering the cap over the substrate upon which the semicon-ductor chip has been mounted.
These methods oi sealing electrical components to protect them ~ro~ the envlronment requiree subJecting the eloctrlcal dovice to considerable thermal strese, because the solder or glae~ must be heated to its melting temperature. For many electrical applioations where e~pensive, high deDsity semiconductor chips are utilised, a hermetic ~eal 1~ required.
8uch seals must allow no detectable leakage when tested with a
~his i~vention relates to the ~ealing oi electrical components.
It i~ frequently important, and sometime~ critical, that electricsl components should be sealed ~rom the atmosphere to prevent their contamination and deterioration. The sealing o~ electrical components is especially important in the ~ield oi semiconductor packaging where the microcircuitry oi a #emi-conductor chip iæ extremely su~ceptible to iailure. The size of the circuitry on such miniature components i8 often oi the order oi microns and the~ are readily subJect to short or open failure upon e~posure to the environment. In addition to failure o~ the connective circuitry, atmospheric contamination oi the semiconductor material itseli may drastically affect its electrical response.
~uch components are ~requently ~ealed and protected irom the atmosphere by iusing a glass layer over them.
Alternatively, a metal cap may be used, ior example, by soldering the cap over the substrate upon which the semicon-ductor chip has been mounted.
These methods oi sealing electrical components to protect them ~ro~ the envlronment requiree subJecting the eloctrlcal dovice to considerable thermal strese, because the solder or glae~ must be heated to its melting temperature. For many electrical applioations where e~pensive, high deDsity semiconductor chips are utilised, a hermetic ~eal 1~ required.
8uch seals must allow no detectable leakage when tested with a
- 2 - *
.,,. ,~
helium ~ass spectro~eter leak te~ter oi sensitlvity 1 s 10-8 scc/sec. in accordance with MII,Standard 88~. Pre~ioue method~
o~ iorming them have in g~neral in~ol~ed delicate and e~pensive ~ealing operations, ior e~ample preciou~ ~etal soldering or the ~u~ion oi a sealing glaaa to it~eli and to metallic leads. Furthermore, once a component i~ protectod fro~ the atmo~phere by such methods, it cannot be ea~ily replaced. On tho other hand, ii changes in circuitry are r~quired, the iabrication of an entirely neY packago i8 oiten required.
The present invention provides a method Or sealing an electrical co~ponent ~hich co~prises posltioning the component on a sub~trate having means ~or electric~l~y connecting tbe ¢o~po~ent and ha~ing a ~all or walls to eurround said ¢omponent, inJerting into an arsa deiined by said ~all(~) and over sald componRnt a heat-recoverable seallng member having transverse dimension~ less than said area deiinea by the nall(s), ~nd ~ar-lng said eealiGg mber to its heat stable etate 80 that itB tran~v~reo di~eneions increas- and a seal i~ oi~ectod.
It ~11 bo approciated that more than one olectrical coaponont ma~ bo sealod agalnst the atmoephere or an~ other on~iro~nt by a dnglo heat-reco~erable sealing membor.
~po~ rooo~ery the sealing member may contact the ~ tB) o~ the ~ubetrato direotly and ezert a eealing pro88uro upon thom. For tbis pUrpOBO the w~llte) may be ehap-d to nhanoo tho ~eallng e~reot~ ror e~a~ple they may be ~or~ed ~th _ ~ _ ~O~
a lip or shoulder upon which the edge~ oi the sealing member will ~it after recovery. Pre~erably, however, the wall~s) comprise a ~eali~g ring in which the heat-recoverable eealing member i6 positionea prior to recovery. Such a ring may, ~or e~ mple? be made from a metal or a hard plastics material and may be bonded to the substrate, for e~ample a ceramic substrate, by kno~n technique~ ~uch as ~oldering or brazing. The sealing ring ia preferably contoured to enhance the seal iormed upon recovery and may, for esample, be formed with an inward bend 0 80 as to iorm a V-shapæ ~to which the edges of the sealing member ~111 wedge upon recovery.
The seali~g member is preferably one which h~8 been deformed irom a flat disc shape to a dish shape and which, upon recovery, will return towards its original ilat shape.
~hen such a di3h shape ~ealing member i3 employed the iorces e~erted upon the ~all upon reco~er~ may easily be calculated.
The forces ehould be such 80 a8 to de~orm the inner sur~ace oi the wall(s) or the ae~l~ng ring sufii¢iently to se~l the component, but not 80 great as to crack the wall(s) or the sealing ring. The iorce at the edge may be calculated, ior e~ample, by using etress-strain formulae such ae thoee given in ~Formulas ror ~tress-Strain~ ~oark, 4th ~dition, ~cGraw ~ill, 1965, psge 303. B~ ad~usting the height and thickne~s o~ the dish the rorces at the interface may be controlled 80 as 2~ to glve an ef~ecti~e seal ~ithout an~ danger o~ crac~lng.
The tra~verse dimensions Or the deformed di8c should 10~
be slightly les~ than the transver#e dimen~ions o~ the wall(s) or the seallng ring. Thu~ ~or a wall dimension oi .500 inche~
the tran~verse dimen~ion of the di~c is preierably .495 inches.
With ~uch dimension~ the disc can easily be placed in~ide the Rubstrate walls whil~t in it~ unrecovered ~tate, but cannot return completely to it6 original flat iorm of tran3ver3e dlmen~ion greater than .500 inohes, thus ensuring that a pressure i8 e~erted at the inter~ace.
~lthough the use oi a disc shaped sealing member i~
pre~erred becau~e it i~ easy to calculate the recovery forces generated at the interiace, it will be appreciated that the particular size and shape oi the seal~ng member will often be dictated by the requirod configuration o~ the ~inal article, e.g. the electronic package. The edge forces of various other shapes, including squaree and rectangles ma~ be calculated appro~imately iro~ stress-strain for~ulaeO
~dditionally, the coniiguration oi the eeall~g member ~ay bo de~gned 80 as to increaee the sealing force, to aid correot positioning oi the sealing member prior to reco~ery or, in some cases, to iacilitate removl~l oi the sealing member at a later stage. For e~ample, a generally disc shaped ~ealing member ma~ bo provided ~ith a control protrusion ~hich ~acilitstes h~ndling oi the member using a suitable toolO
~he ~ost important advantages o~ the pre~ent invention are deri ed irom the ~ealing member being heat-reco~erable, ~eat-recoverable articles, i.e. tho~e ~hich ha~e been de~or~ed 1 04 ~
from a fir~t heat-~table con~iguration to a second heat-unstable coniiguration and which are capable o~ returning, or reco~ering, to~ard~ aaid fir~t configuration upon the application o~ heat alone, have ~ound man~ applications in diverse iields. Such articles have typically been made irom polymeric materials, especially cross-linked polymers, and have been described, ~or e~ample, in U.S. Patents Nos. 2,027,g62 (Currie), 3,0B6,242 (Cook et al) and 3,415,287.
Quite recently, it has been discovered that such articles can also be m~de irom certaln metals, sometimes called ~memory metals~ or ~memory allo~sn. The~e metals e~h~bit changes in ~trength and coniigurational characteristics on passing through a transitlon temperature, in mo~t ca~es the transition temperature between the martensiti¢ and austenitic states, and can be used to make heat-recoverable articles by doiorming an arti~le made irom then whilst the metal is in it~
martensitic, low temperature, state. ~he articlo will retain its deiormed coniiguration until it i~ ~armed above the tran-sition temperature to the austenitic state ~hen it will reco~er to~ards its original configurationO The derormation used to placed the material in the heat-unstable coniiguration i8 com~only reierred to as thermally recoverable pla~tic deior~a-tlon snd ¢an also, in certain csse~, be imparted by introdu¢~n~
strains into the article above the transition temperature~
~hereupon the article assumes the derormed coniiguration on oooling through the transition temperature. It should be 1O~Z~l~
uDderstood that the tran~ition temperature may be a tempera-ture range and that, a~ h~steresis usually o¢curs, the precise temperature at which transition occur~ m~y depend on whether the temperature is rising or ~alllng. Furthermore, the tran~ition temperature is a function of other parameters, in-cluding the stress applied to the material, the temperature rising with increasing stress.
~mon~st such memory metals there may especially be mentioned various alloys o~ titaniu~ and nickel which are described, ~or example, in U.~. Patents ~o~. 3,174,851,
.,,. ,~
helium ~ass spectro~eter leak te~ter oi sensitlvity 1 s 10-8 scc/sec. in accordance with MII,Standard 88~. Pre~ioue method~
o~ iorming them have in g~neral in~ol~ed delicate and e~pensive ~ealing operations, ior e~ample preciou~ ~etal soldering or the ~u~ion oi a sealing glaaa to it~eli and to metallic leads. Furthermore, once a component i~ protectod fro~ the atmo~phere by such methods, it cannot be ea~ily replaced. On tho other hand, ii changes in circuitry are r~quired, the iabrication of an entirely neY packago i8 oiten required.
The present invention provides a method Or sealing an electrical co~ponent ~hich co~prises posltioning the component on a sub~trate having means ~or electric~l~y connecting tbe ¢o~po~ent and ha~ing a ~all or walls to eurround said ¢omponent, inJerting into an arsa deiined by said ~all(~) and over sald componRnt a heat-recoverable seallng member having transverse dimension~ less than said area deiinea by the nall(s), ~nd ~ar-lng said eealiGg mber to its heat stable etate 80 that itB tran~v~reo di~eneions increas- and a seal i~ oi~ectod.
It ~11 bo approciated that more than one olectrical coaponont ma~ bo sealod agalnst the atmoephere or an~ other on~iro~nt by a dnglo heat-reco~erable sealing membor.
~po~ rooo~ery the sealing member may contact the ~ tB) o~ the ~ubetrato direotly and ezert a eealing pro88uro upon thom. For tbis pUrpOBO the w~llte) may be ehap-d to nhanoo tho ~eallng e~reot~ ror e~a~ple they may be ~or~ed ~th _ ~ _ ~O~
a lip or shoulder upon which the edge~ oi the sealing member will ~it after recovery. Pre~erably, however, the wall~s) comprise a ~eali~g ring in which the heat-recoverable eealing member i6 positionea prior to recovery. Such a ring may, ~or e~ mple? be made from a metal or a hard plastics material and may be bonded to the substrate, for e~ample a ceramic substrate, by kno~n technique~ ~uch as ~oldering or brazing. The sealing ring ia preferably contoured to enhance the seal iormed upon recovery and may, for esample, be formed with an inward bend 0 80 as to iorm a V-shapæ ~to which the edges of the sealing member ~111 wedge upon recovery.
The seali~g member is preferably one which h~8 been deformed irom a flat disc shape to a dish shape and which, upon recovery, will return towards its original ilat shape.
~hen such a di3h shape ~ealing member i3 employed the iorces e~erted upon the ~all upon reco~er~ may easily be calculated.
The forces ehould be such 80 a8 to de~orm the inner sur~ace oi the wall(s) or the ae~l~ng ring sufii¢iently to se~l the component, but not 80 great as to crack the wall(s) or the sealing ring. The iorce at the edge may be calculated, ior e~ample, by using etress-strain formulae such ae thoee given in ~Formulas ror ~tress-Strain~ ~oark, 4th ~dition, ~cGraw ~ill, 1965, psge 303. B~ ad~usting the height and thickne~s o~ the dish the rorces at the interface may be controlled 80 as 2~ to glve an ef~ecti~e seal ~ithout an~ danger o~ crac~lng.
The tra~verse dimensions Or the deformed di8c should 10~
be slightly les~ than the transver#e dimen~ions o~ the wall(s) or the seallng ring. Thu~ ~or a wall dimension oi .500 inche~
the tran~verse dimen~ion of the di~c is preierably .495 inches.
With ~uch dimension~ the disc can easily be placed in~ide the Rubstrate walls whil~t in it~ unrecovered ~tate, but cannot return completely to it6 original flat iorm of tran3ver3e dlmen~ion greater than .500 inohes, thus ensuring that a pressure i8 e~erted at the inter~ace.
~lthough the use oi a disc shaped sealing member i~
pre~erred becau~e it i~ easy to calculate the recovery forces generated at the interiace, it will be appreciated that the particular size and shape oi the seal~ng member will often be dictated by the requirod configuration o~ the ~inal article, e.g. the electronic package. The edge forces of various other shapes, including squaree and rectangles ma~ be calculated appro~imately iro~ stress-strain for~ulaeO
~dditionally, the coniiguration oi the eeall~g member ~ay bo de~gned 80 as to increaee the sealing force, to aid correot positioning oi the sealing member prior to reco~ery or, in some cases, to iacilitate removl~l oi the sealing member at a later stage. For e~ample, a generally disc shaped ~ealing member ma~ bo provided ~ith a control protrusion ~hich ~acilitstes h~ndling oi the member using a suitable toolO
~he ~ost important advantages o~ the pre~ent invention are deri ed irom the ~ealing member being heat-reco~erable, ~eat-recoverable articles, i.e. tho~e ~hich ha~e been de~or~ed 1 04 ~
from a fir~t heat-~table con~iguration to a second heat-unstable coniiguration and which are capable o~ returning, or reco~ering, to~ard~ aaid fir~t configuration upon the application o~ heat alone, have ~ound man~ applications in diverse iields. Such articles have typically been made irom polymeric materials, especially cross-linked polymers, and have been described, ~or e~ample, in U.S. Patents Nos. 2,027,g62 (Currie), 3,0B6,242 (Cook et al) and 3,415,287.
Quite recently, it has been discovered that such articles can also be m~de irom certaln metals, sometimes called ~memory metals~ or ~memory allo~sn. The~e metals e~h~bit changes in ~trength and coniigurational characteristics on passing through a transitlon temperature, in mo~t ca~es the transition temperature between the martensiti¢ and austenitic states, and can be used to make heat-recoverable articles by doiorming an arti~le made irom then whilst the metal is in it~
martensitic, low temperature, state. ~he articlo will retain its deiormed coniiguration until it i~ ~armed above the tran-sition temperature to the austenitic state ~hen it will reco~er to~ards its original configurationO The derormation used to placed the material in the heat-unstable coniiguration i8 com~only reierred to as thermally recoverable pla~tic deior~a-tlon snd ¢an also, in certain csse~, be imparted by introdu¢~n~
strains into the article above the transition temperature~
~hereupon the article assumes the derormed coniiguration on oooling through the transition temperature. It should be 1O~Z~l~
uDderstood that the tran~ition temperature may be a tempera-ture range and that, a~ h~steresis usually o¢curs, the precise temperature at which transition occur~ m~y depend on whether the temperature is rising or ~alllng. Furthermore, the tran~ition temperature is a function of other parameters, in-cluding the stress applied to the material, the temperature rising with increasing stress.
~mon~st such memory metals there may especially be mentioned various alloys o~ titaniu~ and nickel which are described, ~or example, in U.~. Patents ~o~. 3,174,851,
3,351,46~, 3,753,700, 3,759,552, British Pate~ts No~. 1,327,441 and 1,327,442 and N~S~ Publication SP 5110, ~55-Nitinol-The ~lloy ~ith a ~emory, etc.~ (U.S. Governme~t Printi~g Of~ice, Washington, D.O. 1972). ~he property o~ heat reco~erabtl~ty has not, ho~ever, been solely con~ined to such titanium,nickel alloys. ~hu~, ~or example, various beta-brass alloys have been demonstrated to eshibit thi~ property in, e.g. N. Nakan~ki et al, ~cri~ta Metallur~ica 5, 433_440 (Ber&amon Prese 19 n ) snd such material~ may be doped to lower their trsnsition temp-eratures to cryogenic regimes by kno~n techniques. ~1m~larly, 304 etai~less steels ha~e be-n aho~n to en~o~ such charaoterls-tlce, ~. B~a i et al, id at pp. 663-68.
Both bypes o~ heat-recoverable material can be u~ed to ~or~ the sealing member u~ed i~ the process o~ the present invention.
~or e~smple, a metal sealing member oan be de~ormod 1 04 ~
whilst in the martensitic state to such a dimension that it fits snugly within a substrate onto which the elect~ical component has been placed. Upon in~erting the deiormed sealing member into the sub~trate and warming it to the austenitic state the sealing member attempts to recover to its ori~inal configuration e~erting a substantial iorce against the substrate into which it has been inserted, the ~orce being suf~icient to ~eal the electrical component. ~ikewise, in the case o~ plastics sealing members, by heating and derorming a heat-recoverable pol~meric material to the appropriate dimension and then quenching it at that dimension, upon heating, the plastics will attempt to recover to its original con~iguration. By accurately dimensioning the sealing member as well as the substrate, sealing pressure may be accurately and reproducibly controlled so as to seal the e]ectrical component.
In the case of metals, transition to the au~tenitic stable state generally occurs at or below room temperature 80 the electrical components are not sub~ected to heat which may cause thermal degradation. In the case o~ heat-reco~erable plastics, heat reco~ery wlll generally take place at or below 300F, well below temperatures which will cause thermal degradhtion oi solder connections or o~idation oi conductors.
~mong~t suitable metals there may be mentioned those having transition temperatures within the range o~ irom ~135C to -196C, e~peciPlly nickel-titaniu~ alloys, ior e~ample~ an allo~ containing 47.1 atom~ percent nlckel, 49.4 104Zl~
atom percent titanium and 3.5 atom percent iron, which ~lloy has a tran~ition temperature o~ appro~imately -125C. Such an alloy can readily be brought into its martensitic st~te by immer~ing it in llquid nitrogen.
~mongst suitabls polymeric material~ there may eepecially be mentioned polgarylene plastics. 2hese are polym~r~ consisting predom~n~ntly of aryl, e.g. phenyl or substituted phenyl, groups ~hich may be linked, ~or example, by direct linkages or b~ alkylene, carbonyl, sulphonyl or ether linkages, or mixtures oi the above linkages. Preierred polyarylenes are des~ribed in Belgian Patente Nos. 779,457;
779,458 and 779,459. T~ese materials may hav a highly crystalline nature and, even without cross-linking, can be deiormed at roo~ tomporature and yet still have sufricient elastic memory to return to their orlginal configuration upon heating, thereb~ e~erting a iorce suiricient to eirect a seal.
To ensure that the sealing member ~1l give a completely eiiective seal it ~ill pre~erably be made rrom a hard, non-deiormable material ~hen the substrate Nall or the eePling ring is soit and deiormable. On the other hand, tho ~ealing m~ber ma~ bo ~de irom a soiter, d-~or~able ~Qteria ~h n tho ~ubstrste ~all i8 itseli hard and non-deiorDable. I~
all oases the material~ should be colected and tho dimensions oi the sealing ~omber choson to en~ure that a au~iicient pressur is e~erted upon the ~ubstrato ~al~ to cau~e tho ~oftor materlal at tho lnter~aco to de~orm and thu~ 8eal the olectrioal ~04Zl~i componentO Thus, for example, when a metal or hard~ non-de~ormable plastic~ sealing member iB employed the sub~trate wall(s) or the sealing ring will pre~erably be ~ormed irom a soft metal, e.g. gold, nickel or tin, or a pla~tic~ material which will yield upon recovery of the sealing member ~o as to ~orm a gas-tight seal at the inter~ace.
It will be eeen that by the present invention there i8 provided a method of sealing electrical components which i8 more reliable and less costly than the methods previously employed. ~nother important advantage is that the electrical component or æub~trate is not sub~ected to excessively high temperatures, thereby permitting the use o~ a wider range of component material~ and substrates, including plastics.
~nother important advantage is that the sealing member can be readily removed to expose the electrical component ii repair or replacemenb is necessary. In the previously employed methods u8ing, ~or ezample, glas~ or solder cap~ it ~as impossible to remove the sealing member without sub~e¢ting the package to high temperatures. In the present invention,however, a metal sealing member can readily be removed by immer0ing the package in liquid nitrogen 80 as to cool the metal to its martensitlc state. In this state the sealing member may be deiormed and removed. ~lternatively the metal sealing member could be remo~ed by crushing it ~hilst in the austenitic ~tate.
Plaatic sealing members can be removed by heating them to a temperature at which they ca~ be de~ormed and romoved ~rom tho 104Zll~
package. In all casea removal i~ racilitated by the provision of a protru~ion on the soaling member, as described above.
It will be appreciated that one oi the moqt important applicationq oi the present invention le in the iield o~
electronics, especiall~ in the manufacture Or electronic packages. ~ccordingly, the ~ubstrate 18 pre~erably one whlch is suitable ior the mounting of electronic components, belng made, io~ eYample, ~rom an inorganic in~ulative material ~uch as a ceramic or a glass or an organic in~ulative material such as a poly~eric material. The neceasary means ior electrical connection may be metalllzed on said substrate by conventional methods or may be diacrete wires provided on or within said substrate.
Various ~orms o~ the present invention will now be described, by way o~ esample only, with rePerence to the accompanying drawings, in whichs ~igure l is a top vie~ o~ an electronic pac~age suitable ior use in the present invention;
Figure 2 is a section through said package a~ter an eloctrical component has been ~ealed bherein in accordance with the present lnvention;
~lgure ~ 18 an enlarged view taken ~rom Pigure 2 ohowing more clearly the lnteriace bet~een the aealing member and the substrate ~
~igure~ 4 to 6 repreaent dii~erent sealing membere ~or use in the present invention, beiore and after doformation;
lO,~
~igure 7 iq a section show~ng a ~ubetrate provided with a sealing ring in acoordance with the pre~ent in~ention; and Figure 8 i~ a sectional ~iew illustrating a method o~ deiorming and in~erting the sealing member in one operation.
Referring now to ~igures 1 and 2 the electronic package l comprises sultable substrate 2 metallized ~ith electrical conductors 4 to pro~ide input/output means ~or an electrical component 6 shown in Figure 20 &b~trate 2 may be made o~ any insulative material, including inorganic ineulators ~e.g. ceramics ~nd gla88) or organic insulators (e.g. epo y resins, phenolic resins, melamine resins, nylon, polyesters, Teilon (~rade Mark), polyimide~ and polyarylenee)O When organic insulator3 are used as the aubstrate material, rein-foroing agents such as glass iibre or microspheree are desirable to impart the required rigidit~ to the electronic packag~ 1.
~ metallized die attach pad 8 i~ utilized ior receiving the component 6 to be attached and electrically connected. The die attach pad 8 le generally metallized with a noble metal such ae gold. ~imilarly conductore 4 may have a top layer o~
gold, beneath which may be less e~pensive metal~ euch as copper.
Preierably, the metal conductors 4 are depoLqited onto the subetrate 2 by meanH oi ~nown techn~ques such ae sputtering>
vapour deposition or electroplating. Eowever, discrete wiring ~a ~ aleo be u~ed in the electronic packages ueed in the lO~
pre~ent inYention. The electrical conductors 4 are then connected to a second level packaging (not shown) vla conductor~
10. The substrate 2 may be oi the multi-layer variety 80 that the conductor~ 10 are sandwiched there between. 3uch ~ub~trates permit denser packaging since multilayer circuitry may be utilized. Of course, a ~ingle layer substrate 2 may also be utilized where high circuit den~ity i~ not required. As be~t seen in Figure 2, a wall 12 i~ provided ior encompa~sing the die attach pad 8 upon ~hich the electrical component 6 i9 to be attachedO
~ter positioning oi the electronic component 6 over die attach pad 8, a heat recoverable sealiDg member 14 i~
placed into the wall~ 12 and over the component 6 ~o a~ to seal the component irom the atmosphere.
~eferring to Figure 3, wall 12 i9 provided with a lip 18 to receive the heat recoverable ~ealing member 14. The lip auriace at which a seal between the heat-recoverable sealing member 14 and the wall 12 i~ formed ehould be made ~ro~ a material which will deiorm upon the esertlon oi iorce b~ the heat-recoverable material. In the case oi a tit~n~umr nickel metal sealing member, the lip suriace should b~ made iro~ a material Hoiter than the titanium-nickel allo~, e.gO
gold, ~iokel or a plastics material.
8ealing member 14 ma~, ior esample, be prepared irom a planar diac oi a nickel titaniu~ allo~ containing 4701%
nickel, 49.4% titaniu~ and 3.5% iron. This co~po~itio~ result~
~04i~
in a material with a transition temperature oi appro~imately -125Co The di~c i~ reduced to a temperature below its transition temperature by immer~ing it in liquid nitrogen which exhibits a ~table temperature o~ -196C. While held at thie reduced temperature, the di~c i~ ~ubJected to su~icient iorce, e.g. in a prees, to cau~e thermally recoverable plastic deiormation to take place whereby the di~c is placed in a heat-un~table diehed configuration. ~he deiormed disc i~ held at a temperature below it~ transition temperature, e.g. by continued immersion in liquid nitrogen, until it i8 ready ior useO
The disc 14 is inserted into the walled ~ubstrate 2 while in the cooled ~tate, after ~hich it is allowed to war~O
This method results in little i~ any thermal stress. Ob~ioualy, the electrical ¢omponent is not sub~ected to high temperatures as ~as the case ~ith the prior art methods. In most instances, the entire electronic package 1 can be cooled to liquid nitrogen temperature during the sealing operation, although this ie not essential.
~lternatively, member 14 may be made oi a polymer material capable o~ being made heat-recoverable 80 as to esert a iorce ~hen caused to recover, e.g. a polyarylene.
The coniiguration oi sealing member 14 ehould be euch ae to iit eaeily into wPll~ 12 Nhile in the deformed state.
The use o~ round walls with a heat-recoverable member which has been derormed rrom a rlat shape to a dish i8 particularl~
euited ior this application since the sealing pressure8 o~ tho ~ ~4 ~
wall may be readily calculated. Protrusion 16 i~ provided on the heat-recoverable sealing member 14, ~o as to allow a holding tool to insert and properly position the member withln the walls 12 of the electronic package 1.
The surface con~iguration of the sealing member~ 14 may be de~igned and deformed ~o as to increase the ~ealing ~orce or aid in insertion of the member into the substrate walls.
Figure 4a is a cross-sectional view oi a ilat disc prior to de~ormation with Figure 4b depicting the disc a~ter deformation.
Upon warming the deiormed disc to its stable ~tate, the disc will tend to return to the original shape, thereby e~erting a iorce against the substrate walls.
~igures 5a and 5b depict a disc cross ~ection beiore and after deiormation having a large control protrusion which assists the insertion oi the disc into the walls oi the substrate.
Figures 6a and 6b depict a ilat disc which is de~ormed into a ~doughnut~ shape. ~his configuration result~
in a substantiall~ horizontal iorce being e~erted by the member agalnst the substrate wall on wQrming.
~8 e~plained above, the wall may be an integral part oi the substrate, and have the same composition as the aubetrate. However, becauee o~ the hardness o~ inorganic substrate~ euch ae ceramic8 or glass, it is preierable to provide a wall having a~ lnner 8ur~ace o~ con~iderably softer materlalO Thus, a eep~rate metallic ring may be attached to 1042~1~
the ceramic ~ubstrateJ the ring having that portion oi its inner ~uriace which iB contacted by the heat-recoverable sealing member 14 coated with a ~o~t metal quch as gold or nickel. Of course, where the wall 12 and the substrate 2 iorm an integral component, such as a ceramic, the inner wall ma~
still be coated with a soiter material ~uch a~q gold, nickel or tin. When the ~ub~trate and wall are iormed irom softer, organic inqulators, coating oi the interior suriace of the wall with a soft material may not be necessary.
~owever, even if the interior suriace oi the ~all i8 a suitable soft material, it may ~till be desirable to provide a sealing ring into whi¢h the sealing member can be tightly wedged.
For e~ample, Figure 7 illustrate3 the u~e oi a eealing ring eo that tho ~ealing member does not directly contact the subetrate wall~. The ring 18 is preferably made oi a rigid material such a~ ~ovar (Trade Mark) (an alloy oi ¢opper, ni¢kol and iron having a ¢oeificient oi e~pansion similar to that oi glas~). Preierably, the ring is coniigured with an inward bend oo as to iorm a ~-ahape into whi¢h the sealing member, upon re¢o~ery, will ~edge. ~nlike the straight side wall oon-iiguratlon ehown in Figure 3, the Y configuratlon en~ures retention oi the disc 14 and a "double seal" on two quriaces oi the ring 18. The ring 18 may be bonded to substrate 20 on metallized pad~ 22 b~ known techniques such as soldering or brazing. ~he ring 18 i~ placed over the substrate ¢avity 24 104;~
into which the electrical component is inserted. Input/output lead~ 26 are provided for connection with an electrical component.
Figure 8 illustrates a method of derorming the sealing member and posi~ioning it o~er the electrical component in one operation. An electrical component, similar to that shown in ~lgure 2, is sealed ~ia a heat-recoverable sealing member 30 which iB deiormed by punch 32 into a concave configuration.
The top w~lls Or the substrate 2 de~ine an opening the dimensions oi which are slightl~ less than those Or the undeformed sealing member, BO that upon insertion and operation of the punch 3 the member 30 is de~ormed to the concave configuration shown. The walls 36 are curved to form a lip 34 upon which the con¢a~e sealing member 30 sits rlush. The lip 34 al~o ~er~es as a ~top to pre~ent the sealing member 30 irom pressing and damaging the electrical component 6.
In the case oi a metal sealing member 30, the member iB inserted and de~ormed in its unstable m2rtensitic state~
and after in~ertion i8 allo~ed to return to its stable austenitic state. The member 30 will attempt to return to its original flat configuration, eserting pressure again~t the ~alls and ~ealing the electrical component 6.
In the oase o~ a plastics sealing member 30, a heat-recoverable material is deformed during insertion, after which lt i8 heated to cau~e it to esert pressure and seal the electrical component 6.
Both bypes o~ heat-recoverable material can be u~ed to ~or~ the sealing member u~ed i~ the process o~ the present invention.
~or e~smple, a metal sealing member oan be de~ormod 1 04 ~
whilst in the martensitic state to such a dimension that it fits snugly within a substrate onto which the elect~ical component has been placed. Upon in~erting the deiormed sealing member into the sub~trate and warming it to the austenitic state the sealing member attempts to recover to its ori~inal configuration e~erting a substantial iorce against the substrate into which it has been inserted, the ~orce being suf~icient to ~eal the electrical component. ~ikewise, in the case o~ plastics sealing members, by heating and derorming a heat-recoverable pol~meric material to the appropriate dimension and then quenching it at that dimension, upon heating, the plastics will attempt to recover to its original con~iguration. By accurately dimensioning the sealing member as well as the substrate, sealing pressure may be accurately and reproducibly controlled so as to seal the e]ectrical component.
In the case of metals, transition to the au~tenitic stable state generally occurs at or below room temperature 80 the electrical components are not sub~ected to heat which may cause thermal degradation. In the case o~ heat-reco~erable plastics, heat reco~ery wlll generally take place at or below 300F, well below temperatures which will cause thermal degradhtion oi solder connections or o~idation oi conductors.
~mong~t suitable metals there may be mentioned those having transition temperatures within the range o~ irom ~135C to -196C, e~peciPlly nickel-titaniu~ alloys, ior e~ample~ an allo~ containing 47.1 atom~ percent nlckel, 49.4 104Zl~
atom percent titanium and 3.5 atom percent iron, which ~lloy has a tran~ition temperature o~ appro~imately -125C. Such an alloy can readily be brought into its martensitic st~te by immer~ing it in llquid nitrogen.
~mongst suitabls polymeric material~ there may eepecially be mentioned polgarylene plastics. 2hese are polym~r~ consisting predom~n~ntly of aryl, e.g. phenyl or substituted phenyl, groups ~hich may be linked, ~or example, by direct linkages or b~ alkylene, carbonyl, sulphonyl or ether linkages, or mixtures oi the above linkages. Preierred polyarylenes are des~ribed in Belgian Patente Nos. 779,457;
779,458 and 779,459. T~ese materials may hav a highly crystalline nature and, even without cross-linking, can be deiormed at roo~ tomporature and yet still have sufricient elastic memory to return to their orlginal configuration upon heating, thereb~ e~erting a iorce suiricient to eirect a seal.
To ensure that the sealing member ~1l give a completely eiiective seal it ~ill pre~erably be made rrom a hard, non-deiormable material ~hen the substrate Nall or the eePling ring is soit and deiormable. On the other hand, tho ~ealing m~ber ma~ bo ~de irom a soiter, d-~or~able ~Qteria ~h n tho ~ubstrste ~all i8 itseli hard and non-deiorDable. I~
all oases the material~ should be colected and tho dimensions oi the sealing ~omber choson to en~ure that a au~iicient pressur is e~erted upon the ~ubstrato ~al~ to cau~e tho ~oftor materlal at tho lnter~aco to de~orm and thu~ 8eal the olectrioal ~04Zl~i componentO Thus, for example, when a metal or hard~ non-de~ormable plastic~ sealing member iB employed the sub~trate wall(s) or the sealing ring will pre~erably be ~ormed irom a soft metal, e.g. gold, nickel or tin, or a pla~tic~ material which will yield upon recovery of the sealing member ~o as to ~orm a gas-tight seal at the inter~ace.
It will be eeen that by the present invention there i8 provided a method of sealing electrical components which i8 more reliable and less costly than the methods previously employed. ~nother important advantage is that the electrical component or æub~trate is not sub~ected to excessively high temperatures, thereby permitting the use o~ a wider range of component material~ and substrates, including plastics.
~nother important advantage is that the sealing member can be readily removed to expose the electrical component ii repair or replacemenb is necessary. In the previously employed methods u8ing, ~or ezample, glas~ or solder cap~ it ~as impossible to remove the sealing member without sub~e¢ting the package to high temperatures. In the present invention,however, a metal sealing member can readily be removed by immer0ing the package in liquid nitrogen 80 as to cool the metal to its martensitlc state. In this state the sealing member may be deiormed and removed. ~lternatively the metal sealing member could be remo~ed by crushing it ~hilst in the austenitic ~tate.
Plaatic sealing members can be removed by heating them to a temperature at which they ca~ be de~ormed and romoved ~rom tho 104Zll~
package. In all casea removal i~ racilitated by the provision of a protru~ion on the soaling member, as described above.
It will be appreciated that one oi the moqt important applicationq oi the present invention le in the iield o~
electronics, especiall~ in the manufacture Or electronic packages. ~ccordingly, the ~ubstrate 18 pre~erably one whlch is suitable ior the mounting of electronic components, belng made, io~ eYample, ~rom an inorganic in~ulative material ~uch as a ceramic or a glass or an organic in~ulative material such as a poly~eric material. The neceasary means ior electrical connection may be metalllzed on said substrate by conventional methods or may be diacrete wires provided on or within said substrate.
Various ~orms o~ the present invention will now be described, by way o~ esample only, with rePerence to the accompanying drawings, in whichs ~igure l is a top vie~ o~ an electronic pac~age suitable ior use in the present invention;
Figure 2 is a section through said package a~ter an eloctrical component has been ~ealed bherein in accordance with the present lnvention;
~lgure ~ 18 an enlarged view taken ~rom Pigure 2 ohowing more clearly the lnteriace bet~een the aealing member and the substrate ~
~igure~ 4 to 6 repreaent dii~erent sealing membere ~or use in the present invention, beiore and after doformation;
lO,~
~igure 7 iq a section show~ng a ~ubetrate provided with a sealing ring in acoordance with the pre~ent in~ention; and Figure 8 i~ a sectional ~iew illustrating a method o~ deiorming and in~erting the sealing member in one operation.
Referring now to ~igures 1 and 2 the electronic package l comprises sultable substrate 2 metallized ~ith electrical conductors 4 to pro~ide input/output means ~or an electrical component 6 shown in Figure 20 &b~trate 2 may be made o~ any insulative material, including inorganic ineulators ~e.g. ceramics ~nd gla88) or organic insulators (e.g. epo y resins, phenolic resins, melamine resins, nylon, polyesters, Teilon (~rade Mark), polyimide~ and polyarylenee)O When organic insulator3 are used as the aubstrate material, rein-foroing agents such as glass iibre or microspheree are desirable to impart the required rigidit~ to the electronic packag~ 1.
~ metallized die attach pad 8 i~ utilized ior receiving the component 6 to be attached and electrically connected. The die attach pad 8 le generally metallized with a noble metal such ae gold. ~imilarly conductore 4 may have a top layer o~
gold, beneath which may be less e~pensive metal~ euch as copper.
Preierably, the metal conductors 4 are depoLqited onto the subetrate 2 by meanH oi ~nown techn~ques such ae sputtering>
vapour deposition or electroplating. Eowever, discrete wiring ~a ~ aleo be u~ed in the electronic packages ueed in the lO~
pre~ent inYention. The electrical conductors 4 are then connected to a second level packaging (not shown) vla conductor~
10. The substrate 2 may be oi the multi-layer variety 80 that the conductor~ 10 are sandwiched there between. 3uch ~ub~trates permit denser packaging since multilayer circuitry may be utilized. Of course, a ~ingle layer substrate 2 may also be utilized where high circuit den~ity i~ not required. As be~t seen in Figure 2, a wall 12 i~ provided ior encompa~sing the die attach pad 8 upon ~hich the electrical component 6 i9 to be attachedO
~ter positioning oi the electronic component 6 over die attach pad 8, a heat recoverable sealiDg member 14 i~
placed into the wall~ 12 and over the component 6 ~o a~ to seal the component irom the atmosphere.
~eferring to Figure 3, wall 12 i9 provided with a lip 18 to receive the heat recoverable ~ealing member 14. The lip auriace at which a seal between the heat-recoverable sealing member 14 and the wall 12 i~ formed ehould be made ~ro~ a material which will deiorm upon the esertlon oi iorce b~ the heat-recoverable material. In the case oi a tit~n~umr nickel metal sealing member, the lip suriace should b~ made iro~ a material Hoiter than the titanium-nickel allo~, e.gO
gold, ~iokel or a plastics material.
8ealing member 14 ma~, ior esample, be prepared irom a planar diac oi a nickel titaniu~ allo~ containing 4701%
nickel, 49.4% titaniu~ and 3.5% iron. This co~po~itio~ result~
~04i~
in a material with a transition temperature oi appro~imately -125Co The di~c i~ reduced to a temperature below its transition temperature by immer~ing it in liquid nitrogen which exhibits a ~table temperature o~ -196C. While held at thie reduced temperature, the di~c i~ ~ubJected to su~icient iorce, e.g. in a prees, to cau~e thermally recoverable plastic deiormation to take place whereby the di~c is placed in a heat-un~table diehed configuration. ~he deiormed disc i~ held at a temperature below it~ transition temperature, e.g. by continued immersion in liquid nitrogen, until it i8 ready ior useO
The disc 14 is inserted into the walled ~ubstrate 2 while in the cooled ~tate, after ~hich it is allowed to war~O
This method results in little i~ any thermal stress. Ob~ioualy, the electrical ¢omponent is not sub~ected to high temperatures as ~as the case ~ith the prior art methods. In most instances, the entire electronic package 1 can be cooled to liquid nitrogen temperature during the sealing operation, although this ie not essential.
~lternatively, member 14 may be made oi a polymer material capable o~ being made heat-recoverable 80 as to esert a iorce ~hen caused to recover, e.g. a polyarylene.
The coniiguration oi sealing member 14 ehould be euch ae to iit eaeily into wPll~ 12 Nhile in the deformed state.
The use o~ round walls with a heat-recoverable member which has been derormed rrom a rlat shape to a dish i8 particularl~
euited ior this application since the sealing pressure8 o~ tho ~ ~4 ~
wall may be readily calculated. Protrusion 16 i~ provided on the heat-recoverable sealing member 14, ~o as to allow a holding tool to insert and properly position the member withln the walls 12 of the electronic package 1.
The surface con~iguration of the sealing member~ 14 may be de~igned and deformed ~o as to increase the ~ealing ~orce or aid in insertion of the member into the substrate walls.
Figure 4a is a cross-sectional view oi a ilat disc prior to de~ormation with Figure 4b depicting the disc a~ter deformation.
Upon warming the deiormed disc to its stable ~tate, the disc will tend to return to the original shape, thereby e~erting a iorce against the substrate walls.
~igures 5a and 5b depict a disc cross ~ection beiore and after deiormation having a large control protrusion which assists the insertion oi the disc into the walls oi the substrate.
Figures 6a and 6b depict a ilat disc which is de~ormed into a ~doughnut~ shape. ~his configuration result~
in a substantiall~ horizontal iorce being e~erted by the member agalnst the substrate wall on wQrming.
~8 e~plained above, the wall may be an integral part oi the substrate, and have the same composition as the aubetrate. However, becauee o~ the hardness o~ inorganic substrate~ euch ae ceramic8 or glass, it is preierable to provide a wall having a~ lnner 8ur~ace o~ con~iderably softer materlalO Thus, a eep~rate metallic ring may be attached to 1042~1~
the ceramic ~ubstrateJ the ring having that portion oi its inner ~uriace which iB contacted by the heat-recoverable sealing member 14 coated with a ~o~t metal quch as gold or nickel. Of course, where the wall 12 and the substrate 2 iorm an integral component, such as a ceramic, the inner wall ma~
still be coated with a soiter material ~uch a~q gold, nickel or tin. When the ~ub~trate and wall are iormed irom softer, organic inqulators, coating oi the interior suriace of the wall with a soft material may not be necessary.
~owever, even if the interior suriace oi the ~all i8 a suitable soft material, it may ~till be desirable to provide a sealing ring into whi¢h the sealing member can be tightly wedged.
For e~ample, Figure 7 illustrate3 the u~e oi a eealing ring eo that tho ~ealing member does not directly contact the subetrate wall~. The ring 18 is preferably made oi a rigid material such a~ ~ovar (Trade Mark) (an alloy oi ¢opper, ni¢kol and iron having a ¢oeificient oi e~pansion similar to that oi glas~). Preierably, the ring is coniigured with an inward bend oo as to iorm a ~-ahape into whi¢h the sealing member, upon re¢o~ery, will ~edge. ~nlike the straight side wall oon-iiguratlon ehown in Figure 3, the Y configuratlon en~ures retention oi the disc 14 and a "double seal" on two quriaces oi the ring 18. The ring 18 may be bonded to substrate 20 on metallized pad~ 22 b~ known techniques such as soldering or brazing. ~he ring 18 i~ placed over the substrate ¢avity 24 104;~
into which the electrical component is inserted. Input/output lead~ 26 are provided for connection with an electrical component.
Figure 8 illustrates a method of derorming the sealing member and posi~ioning it o~er the electrical component in one operation. An electrical component, similar to that shown in ~lgure 2, is sealed ~ia a heat-recoverable sealing member 30 which iB deiormed by punch 32 into a concave configuration.
The top w~lls Or the substrate 2 de~ine an opening the dimensions oi which are slightl~ less than those Or the undeformed sealing member, BO that upon insertion and operation of the punch 3 the member 30 is de~ormed to the concave configuration shown. The walls 36 are curved to form a lip 34 upon which the con¢a~e sealing member 30 sits rlush. The lip 34 al~o ~er~es as a ~top to pre~ent the sealing member 30 irom pressing and damaging the electrical component 6.
In the case oi a metal sealing member 30, the member iB inserted and de~ormed in its unstable m2rtensitic state~
and after in~ertion i8 allo~ed to return to its stable austenitic state. The member 30 will attempt to return to its original flat configuration, eserting pressure again~t the ~alls and ~ealing the electrical component 6.
In the oase o~ a plastics sealing member 30, a heat-recoverable material is deformed during insertion, after which lt i8 heated to cau~e it to esert pressure and seal the electrical component 6.
Claims (41)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of sealing an electrical component which comprises positioning the component on a substrate having means for electrically connecting the component and having a wall or walls to surround said component, inserting into an area defined by said wall(s) and over said component a heat-recoverable sealing member having transverse dimensions less than said area defined by the wall(s), and warming said sealing member to its heat stable state so that its transverse dimensions increase and a seal is effected.
2. A method as claimed in claim 1, wherein the wall(s) of the substrate is(are) formed with a lip or shoulder upon which the edges of the sealing member can sit after recovery.
3. A method as claimed in claim 1, wherein the wall(s) comprise(s) a sealing ring into which the sealing member is positioned prior to recovery.
4. A method as claimed in claim 3, wherein the sealing ring is made from a metal or a hard plastics material.
5. A method as claimed in claim 3, wherein the sealing ring is contoured to enhance the seal formed upon recovery of the sealing member.
6. A method as claimed in claim 5, wherein the sealing ring is bent inwardly to form a V-shaped groove into which the edges of the sealing member will wedge upon recovery.
7. A method as claimed in claim 1, wherein the substrate wall(s) or the sealing ring is(are) formed from, or coated with, a soft metal or a plastics material which will yield on recovery of the sealing member.
8. A method as claimed in claim 7, wherein the soft metal is gold, nickel or titanium.
9. A method as claimed in claim 7, wherein the plastics material is a polyarylene.
10. A method as claimed in claim 1, wherein the heat-recover-able sealing member is one which has been deformed from a flat disc shape to a dish shape and which, upon recovery, will return towards its original flat shape.
11. A method as claimed in claim 1, wherein the sealing member is provided with a protrusion to facilitate handling of the member during positioning and removal.
12. A method as claimed in claim 1, wherein the heat-recover-able sealing member is made from a metal.
13. A method as claimed in claim 12, wherein the metal has a transition temperature in the range of from +135°C to -196°C.
14. A method as claimed in claim 12, wherein the metal is an alloy of nickel and titanium.
15. A method as claimed in claim 1, wherein the heat-recover-able sealing member is made from a plastics material.
16. A method as claimed in claim 15, wherein the plastics material is a polyarylene.
17. A method as claimed in claim 1, wherein the substrate is part of an electronic package.
18. A method as claimed in claim 17, wherein the substrate is made from a ceramic or a glass.
19. A method as claimed in claim 17, wherein the substrate is made from an organic insulating material.
20. A method as claimed in claim 1, wherein the electrical component is a semi-conductor chip.
21. A method as claimed in claim 1, wherein the sealing member is deformed to make it heat-recoverable at the same time as it is positioned within the wall(s) of the substrate.
22. A method as claimed in claim 21, wherein the wall(s) of the substrate is(are) provided with means to assit deforma-tion of the sealing member.
23. A package containing an electrical component positioned on a substrate having means for electrically connecting the component, said substrate also having a wall(s) surrounding said component which is sealed against the atmosphere by the provision of a sealing member made of heat-recoverable material, which sealing member covers said component and which has been inserted within the wall(s) and heat recovered so that its transverse dimensions increased to exert a sealing pressure against said wall(s).
24. A package as claimed in claim 23, wherein the wall(s) of the substrate is(are) formed with a lip or shoulder upon which the sealing member sits.
25. A package as claimed in claim 23, wherein the wall(s) comprise(s) a sealing ring within which the sealing member is positioned.
26. A package as claimed in claim 25, wherein the sealing ring is made from a metal or a hard plastics material.
27. A package as claimed in claim 25, wherein the sealing ring is bent inwardly to form a V-shaped groove into which the edges of the sealing member are wedged.
28. A package as claimed in claim 23, wherein the substrate wall(s) or the sealing ring is(are) formed from, or coated with, a soft metal or a plastics material.
29. A package as claimed in claim 28, wherein the soft metal is gold, nickel or titanium.
30. A package as claimed in claim 28, wherein the plastics material is a polyarylene.
31. A package as claimed in claim 23, wherein the sealing member comprises a dish shaped member which has recovered towards a flat disc shape.
32. A package as claimed in claim 23, wherein the sealing member is provided with a protrusion to facilitate removal thereof.
33. A package as claimed in claim 23, wherein the sealing member is made from a metal.
34. A package as claimed in claim 33, wherein the metal has a transition temperature in the range of from +135°C to -196°C.
35. A package as claimed in claim 33, wherein the metal is an alloy of nickel and titanium.
36. A package as claimed in claim 23, wherein the sealing member is made from a plastics material.
37. A package as claimed in claim 36, wherein the plastics material is a polyarylene.
38. A package as claimed in claim 23, wherein the substrate is made from a ceramic or a glass.
39. A package as claimed in claim 23, wherein the substrate is made from an organic insulating material.
40. A package as claimed in claim 23, wherein the package is an electronic package.
41. A package as claimed in claim 40, wherein the electrical component is a semi-conductor chip.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US42142973A | 1973-12-03 | 1973-12-03 | |
| US05/465,561 US4126758A (en) | 1973-12-03 | 1974-04-30 | Method for sealing integrated circuit components with heat recoverable cap and resulting package |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1042116A true CA1042116A (en) | 1978-11-07 |
Family
ID=27025234
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA215,092A Expired CA1042116A (en) | 1973-12-03 | 1974-12-02 | Heat recoverable cap |
Country Status (15)
| Country | Link |
|---|---|
| JP (1) | JPS5842622B2 (en) |
| AT (1) | ATA964874A (en) |
| AU (1) | AU502556B2 (en) |
| BE (1) | BE822904A (en) |
| CA (1) | CA1042116A (en) |
| CH (1) | CH580379A5 (en) |
| DE (1) | DE2457116A1 (en) |
| ES (1) | ES432527A1 (en) |
| FR (1) | FR2253283B1 (en) |
| GB (1) | GB1484177A (en) |
| HK (1) | HK18478A (en) |
| IL (1) | IL46173A (en) |
| IT (1) | IT1033109B (en) |
| NL (1) | NL7415764A (en) |
| SE (1) | SE7415124L (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5427884Y2 (en) * | 1974-06-27 | 1979-09-08 | ||
| JPS57175442U (en) * | 1981-04-30 | 1982-11-05 | ||
| JPS58100446A (en) * | 1981-12-10 | 1983-06-15 | Mitsubishi Electric Corp | Vacuum sealing method |
| JPS60133741A (en) * | 1983-12-21 | 1985-07-16 | Fujitsu Ltd | Semiconductor device and manufacture thereof |
| US4701573A (en) * | 1985-09-26 | 1987-10-20 | Itt Gallium Arsenide Technology Center | Semiconductor chip housing |
| JPH0793393B2 (en) * | 1988-02-22 | 1995-10-09 | 株式会社東芝 | Semiconductor device metal shell |
| FR2710810B1 (en) * | 1993-09-29 | 1995-12-01 | Sagem | Waterproof micro-component housing and method of encapsulation in such a housing. |
-
1974
- 1974-12-02 JP JP49138271A patent/JPS5842622B2/en not_active Expired
- 1974-12-02 CA CA215,092A patent/CA1042116A/en not_active Expired
- 1974-12-03 SE SE7415124A patent/SE7415124L/xx unknown
- 1974-12-03 FR FR7439474A patent/FR2253283B1/fr not_active Expired
- 1974-12-03 ES ES432527A patent/ES432527A1/en not_active Expired
- 1974-12-03 DE DE19742457116 patent/DE2457116A1/en not_active Ceased
- 1974-12-03 NL NL7415764A patent/NL7415764A/en not_active Application Discontinuation
- 1974-12-03 IL IL46173A patent/IL46173A/en unknown
- 1974-12-03 AT AT964874A patent/ATA964874A/en not_active Application Discontinuation
- 1974-12-03 CH CH1602274A patent/CH580379A5/xx not_active IP Right Cessation
- 1974-12-03 AU AU76019/74A patent/AU502556B2/en not_active Expired
- 1974-12-03 GB GB52318/74A patent/GB1484177A/en not_active Expired
- 1974-12-03 BE BE151117A patent/BE822904A/en unknown
- 1974-12-03 IT IT30149/74A patent/IT1033109B/en active
-
1978
- 1978-04-04 HK HK184/78A patent/HK18478A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5842622B2 (en) | 1983-09-21 |
| SE7415124L (en) | 1975-06-04 |
| ATA964874A (en) | 1980-04-15 |
| BE822904A (en) | 1975-06-03 |
| CH580379A5 (en) | 1976-09-30 |
| AU502556B2 (en) | 1979-08-02 |
| IL46173A (en) | 1977-08-31 |
| FR2253283A1 (en) | 1975-06-27 |
| ES432527A1 (en) | 1977-03-01 |
| IT1033109B (en) | 1979-07-10 |
| JPS5087586A (en) | 1975-07-14 |
| IL46173A0 (en) | 1975-03-13 |
| GB1484177A (en) | 1977-09-01 |
| AU7601974A (en) | 1976-06-03 |
| HK18478A (en) | 1978-04-14 |
| FR2253283B1 (en) | 1979-08-10 |
| DE2457116A1 (en) | 1975-08-21 |
| NL7415764A (en) | 1975-06-05 |
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