BGA Rework: Setsebi Tataiso ea Tokiso ea Karolo ea PCB

Selelekela

Likarolo tsa BGA ke life?

Liphutheloana tsa Ball Grid Array (BGA) li emela e 'ngoe ea mahlale a tsoetseng pele ka ho fetisisa a ho kenya holim'a metsi lisebelisoa tsa elektroniki tsa sejoale-joale. Ho fapana le liphutheloana tsa setso tse nang le lead, li-BGA li sebelisa mefuta e mengata ea libolo tsa solder ka tlas'a karolo ho theha likhokahano tsa motlakase le tsa mechini le PCB. Moralo ona o nolofalletsa lipalo tse phahameng tsa li-pin, ts'ebetso e phahameng ea mocheso, le boholo bo fokotsehileng ba liphutheloana—e leng se etsang hore li-BGA li be bohlokoa bakeng sa li-processor, li-memory chip, le li-IC tse rarahaneng li-smartphone, li-server le litsamaiso tsa likoloi.

Hobaneng ha BGA Rework e le Bohlokoa

Ho lokisa botjha ha BGA ho bohlokwa tlhahisong le tokisong ya PCB hobane dikarolo tsa BGA tse nang le sekoli kapa tse hlolehileng di ke ke tsa kopanngwa ka letsoho feela jwalo ka dikarolo tse nang le masoba a phunyeletsang. Dikotwana tse patilweng tsa ho tjhesa tse ka tlasa sephutheloana di hloka mekgwa e ikgethang bakeng sa ho tlosa, ho lokisa sebaka le ho nkela sebaka.

Maemo a tloaelehileng a hlokang hore BGA e sebetse bocha a kenyelletsa liphoso tsa tlhahiso (borokho, likheo, manonyeletso a batang), ho hloleha ho tsoa ho libaesekele tse futhumetseng kapa khatello ea mochini, le litaelo tsa phetoho ea boenjiniere tse hlokang ho ntlafatsoa ha likarolo.

Lisebelisoa le Lisebelisoa tsa BGA Rework

Rework Stations

Mosebetsi o mocha oa BGA o hloka liteishene tse inehetseng tse nang le lisebelisoa tse nepahetseng tsa ho futhumatsa.

• Liteishene tsa ho tsosolosa moea o chesang - Mocheso oa convective o tsepamisitsoeng ka li-nozzles tse lokiselitsoeng o fokotsa khatello ea mocheso likarolong tse potolohileng.
• Sistimi e ncha ea infrared (IR). - Ho futhumatsa ka mokhoa o ts'oanang libakeng tse kholo ho fokotsa oxidation mme ho netefatsa hore mocheso o ajoa.

Sistimi ea Hybrid e kopanyang mahlale a mabeli a fana ka maemo a feto-fetohang, a nolofalletsang basebelisi ho khetha mokhoa o nepahetseng oa ho futhumatsa o ipapisitseng le mofuta oa likarolo le kaho ea boto.

Lisebelisoa tsa Soldering le Flux

Ka ntle ho lisebelisoa tsa mantlha tsa ho futhumatsa, mosebetsi oa BGA o hloka lisebelisoa tse thusang:

• sebetsa ka ho nepahetseng Lisebelisoa tsa tšepe bakeng sa mosebetsi oa ho ama
• Lisebelisoa tsa ho hula ka vacuum bakeng sa ho sebetsana le karolo
• Lisebelisoa tsa Flux (lipene, li-syringe, kapa lisebelisoa tsa ho fana)
• Li-stencil tsa solder kapa li-preforms bakeng sa ts'ebetso ea ho khutlisa

Flux ea boleng bo phahameng e sa hloekang kapa e qhibilihang ka metsi e loketseng motsoako oa solder (e etellang pele kapa e se nang loto) e netefatsa ho koloba hantle le ho fokotsa litlhoko tsa ho hloekisa ka mor'a ho tsosolosa.

tlhahlobo Helmets

Bokhoni bo felletseng ba tlhahlobo bo ke keng ba buisanoa bakeng sa netefatso ea rework ea BGA.

• Limaekerosekopo tsa stereo etsa tlhahlobo ea pono ea ho beha le ho tsamaisana ha solder peista.
• Mekhoa ea tlhahlobo ea X-ray senola liphoso tse patiloeng ka tlas'a BGA-voids, bridging, head-in-pillow, le molumo o sa lekaneng oa solder.
• Tlhahlobo ea optical e ikemetseng (AOI) e fana ka netefatso e potlakileng ea ho nepahala ha sebaka.

Ntle le lisebelisoa tse nepahetseng tsa tlhahlobo, katleho ea BGA e ke ke ea netefatsoa ka ts'epo.

BGA Rework Process Mohato ka Mohato

ho lokisetsa

Tokisetso e phethahetseng e etsa qeto ea sephetho sa rework. Qala ka ho hloekisa PCB ho tlosa litšila tse ka sitisang ho futhumatsa kapa ho hlahloba. Etsa tlhahlobo e kenang ho ngola maemo a teng le ho tseba sekoli se hlokang ho lokisoa. Kenya masking theipi ea mocheso o phahameng kapa tšireletso ea aluminium ho sireletsa likarolo tse haufi-haholo-holo tse nang le litekanyetso tse tlase tsa mocheso oa phallo kapa tse sa utloeleng mongobo. Netefatsa litloaelo tsa likarolo 'me u netefatse litlhoko tsa ngoliso ea pad-to-ball.

Ho tlosoa ha BGA e nang le phoso

Ho tlosoa ha likarolo ho latela boemo bo laoloang ba mocheso. Preheat PCB kaofela ho tloha ka tlase ho fokotsa likhahla tsa mocheso le ho thibela warpage-hangata ho 150-180 ° C ho itšetlehile ka botenya ba boto. Kenya mocheso o lehlakoreng le kaholimo u sebelisa moea o chesang kapa sistimi ea IR, ho latela profil e bonts'ang mokokotlo oa pele oa phallo. Hang ha solder e fihla liquidus, sebelisa vacuum pickup ho phahamisa BGA ka holimo. Le ka mohla u se ke ua thella kapa ua sotha karolo, kaha sena se ka tabola lipampiri ho tloha substrate.

Ho Hloekisa Boto

Ka mor'a ho tlosoa ha motsoako, solder e setseng e tlameha ho tlosoa ho tloha ho liphahlo. Sebelisa copper braid (solder wick) e nang le flux e ncha ho tlosa solder e feteletseng ha sebaka se ntse se futhumetse. Bakeng sa li-deposit tse manganga, tšepe e laoloang ke mocheso e thusa ho bokella solder e setseng. Hloekisa sebaka sa marang-rang ka joala ba isopropyl kapa mochini o tlosang phallo. Lekola tlas'a ho holisa ho netefatsa hore lipache tsohle li bataletse, li hloekile, 'me ha li na mesaletsa e phahamisitsoeng kapa maske a solder a senyehileng.

Phetoho le Soldering

Kenya setlolo sa flux kapa solder setšeng se lokisitsoeng u sebelisa li-stencil kapa phepelo e laoloang. Beha sebaka sa BGA u sebelisa mokhoa oa ho lokisa pono oa seteishene sa rework - ho nepahala mona ho ama chai ka kotloloho. Etsa profil e laoloang ea ho phalla hape: ho tsamaea butle-butle ho isa mocheso o tlase, ho fetela ho metsi, ho tšoara mocheso o phahameng, le ho pholisa ho laoloang. Qoba ho feta tekanyo ea mocheso e boletsoeng ke moetsi. Lumella kopano hore e pholile ka tlhaho; Pholiso e qobelloang e ka baka tšabo ea mocheso le mapetsong a manyane manonyeletsong a solder.

Tlhahlobo ea Kamor'a Mosebetsi o Mocha

Netefatsa BGA e 'ngoe le e 'ngoe e ntlafalitsoeng ka tlhahlobo e hlophisitsoeng. Tlhahlobo ea pono tlas'a ho holisa e tiisa ho lumellana hantle le ho se be teng ha liphoso tsa kantle. Tlhahlobo ea X-ray ea hlokahala ho lekola boleng ba manonyeletso a patiloeng—ho hlahloba likheo tse fetang meeli ea litlhaloso, ho koala lipakeng tsa libolo, liphoso tsa hlooho-ka-mosamo, le ho putlama ha bolo ho nepahetseng. Qetella ka tlhahlobo ea motlakase (ICT kapa tlhahlobo ea ts'ebetso) ho netefatsa hore likhokahano tsohle li sebetsa ka har'a litlhaloso.

Mathata a Tloaelehileng ho BGA Rework

Mefokolo e Kopanetsoeng ea Solder

Borokho ba solder bo etsahala ha libolo tse bapileng li kopana, ho etsa marikhoe a makhutšoane-hangata a bakoang ke pente e feteletseng ea solder, ho se lumellane, kapa bophahamo bo sa lekaneng ba ho ema. Manonyeletso a batang a bakoa ke mocheso o sa lekaneng oa tlhōrō kapa nako ea ho lula, a hlahisa maqhama a lerootho, a kristale a nang le matla a fokolang a mochine. Litšitiso tsa hlooho-in-pillow li hlaha ha motsoako le boto ea solder li hlōleha ho kopana hantle nakong ea ho phalla, hangata ka lebaka la oxidation kapa warpage.

Mathata a Tsamaiso ea Mocheso

Leqephe la ntoa la PCB nakong ea rework ea BGA le bakoa ke mocheso o sa lekaneng kapa likhahla tse ngata tsa mocheso ho pholletsa le kopano. Liboto tse nang le li-multi-layer le tse nang le lifofane tse boima tsa koporo li hloka mekhahlelo e teletsana ea preheat le profil e hlokolosi. Tšenyo ea karolo e bakoang ke mocheso o feteletseng e bonahala e le ho senyeha ha sephutheloana, ho senyeha ha thepa, kapa lisebelisoa tsa motlakase tse senyehileng. Ho phalla ha karolo e haufi ho etsahala ha tšireletso e bontša hore ha e lekane kapa khetho ea nozzle e lumella mocheso hore o fetele ka nģ'ane ho sebaka seo ho shebiloeng ho sona.

Alignment le Pad Tšenyo

Ho se lumellane pakeng tsa libolo tsa BGA le li-pads tsa PCB ho baka li-circuits tse bulehileng kapa likhokahano tsa nakoana. Li-BGA tsa boleng bo holimo (0.4mm le ka tlase) li hloka ho nepahala ho ikhethang - hangata ho feta bokhoni ba matsoho. Ho phahamisa liphahlo kapa cratering nakong ea ho tlosoa ha karolo ho bakoa ke matla a feteletseng a ho tlosa, ho se lekane ha solder liquefaction, kapa mathata a neng a le teng pele a ho khomarela. Li-pads tse senyehileng li ka hloka ho lokisoa ha micro-surgery kapa tsa etsa hore boto e se ke ea lokisoa.

Mekhoa e metle ea ho sebetsa hape ka katleho ea BGA

Thermal Profile Optimization

Hlahisa le ho ngola diprofaele tsa mocheso tse ikgethang bakeng sa mofuta o mong le o mong wa kopano ya PCB . Disebediswa tse fapaneng tsa substrate (FR-4, high-Tg, polyimide, ceramic) di hloka mekgwa e fapaneng ya ho futhumatsa. Profaele e nang le di-thermocouple tse hoketsweng hodima bokahodimo ba BGA le botlaaseng ba PCB ho netefatsa dipharologanyo tse nepahetseng tsa mocheso. Laola sekgahla sa ho futhumatsa le ho phodisa ka hare ho 2-4°C/motsotswana ho fokotsa kgatello ya mocheso. Netefatsa diprofaele dikopanong tsa ditshila pele o etsa tlhahiso botjha.

Taolo ea Ts'ebetso le Mokhoa

Sebelisa k'hemistri e loketseng ea flux e tsamaellanang le motsoako oa solder-ha ho hloekile phallo bakeng sa lits'ebetso tse ngata, e qhibilihang ka metsi ha ho hloekisoa ka mabifi. Sebelisa pente ea solder kapa flux ka mokhoa o ts'oanang; ho koaheloa ho sa tsitsang ho bakang ho koloba ho sa lekana. Boloka boholo bo nepahetseng ba nozzle - li-nozzle li lokela ho ba kholoanyane ka 2-5mm ho feta karolo ka lehlakoreng le leng. Hloekisa lisebelisoa tsa rework khafetsa ho thibela tšoaetso. Basebetsi ba nang le litsebo ba nang le lithupelo tse ngotsoeng ba ntlafatsa haholo litefiso tsa pele tsa pele mesebetsing ea BGA rework.

Lintlha tsa Tšireletso bakeng sa BGA Rework

Tšireletseho ea Solder le Lik'hemik'hale

Leaded solder (SnPb) e hloka ho tšoaroa ka hloko ho thibela ho pepeseha ha loto-hlapa matsoho hantle ka mor'a hore u kopane, qoba ho jella libakeng tsa mosebetsi, 'me u sebelise PPE e loketseng. Li-alloys tse se nang lead (SAC305, joalo-joalo) li hloka mocheso o phahameng oa ts'ebetso, ho eketsa kotsi ea ho cha. Mosi oa Flux le metsoako ea ho hloekisa e hloka moea o lekaneng; mosi oa lehae sebakeng sa rework o nka mosi mohloling. Latela maqephe a lintlha tsa polokeho ea thepa bakeng sa lik'hemik'hale tsohle tse sebelisitsoeng ts'ebetsong ea ts'ebetso.

ESD le Tšireletso ea Lisebelisoa

Tšireletso ea electrostatic discharge e bohlokoa nakong eohle ea BGA rework. Boloka libaka tsa ts'ebetso tse sireletsehileng tsa ESD ka limmete tse theohileng fatše, likhoele tsa letsoho le ionization moo ho loketseng. Tšoara li-BGA feela libakeng tse sirelelitsoeng tsa ESD. Tšireletseho ea lisebelisoa e kenyelletsa ho ts'oaroa hantle ha nozzle ea moea o chesang (thempereichara e fetang 350 ° C nakong ea ts'ebetso), ts'ebetso e sireletsehileng ea PCB ho thibela marotholi a boto, le tlhokomelo ea kamehla ea lisebelisoa tsa ho futhumatsa ho netefatsa ho nepahala ha calibration.

fihlela qeto e

Ho lokisa botjha ha BGA ke bokgoni ba bohlokwa tlhahisong le tokisong ya sejwalejwale ya PCB. Tlhaho e patehileng ya manonyeletso a solder a BGA e hloka disebediswa tse ikgethang, taolo e matla ya tshebetso, le tlhahlobo e phethahetseng mohatong o mong le o mong. Katleho e hloka ho utlwisisa tshebedisano pakeng tsa diprofaele tsa mocheso, k'hemistri ya phallo, le tsamaiso ya mechini.

Ka ho latela mekhoa e metle e thehiloeng-ho lokisetsa hantle, ho futhumatsa ho laoloang, ho lumellana hantle, le ho netefatsa ka botlalo ka mor'a ho tsosolosa - bahlahisi ba fumana liphello tse ka tšeptjoang tse finyellang litlhaloso tsa boleng ba pele.