Nhungamiro Yakakwana yePCB Surface Inopedza: Kusarudzwa, Zvivakwa, uye Kuvimbika Kufunga

Nhanganyaya kuPCB Surface Inopedza

Kupedzwa kwePCB pamusoro pemabhodhi kunoita basa rakakosha pakuona hunhu hwekupedzisira uye kuvimbika kwemabhodhi. Kupedzwa kwepamusoro pemabhodhi kunopa mukana wakanaka wekusonesa, kuramba ngura nekuoxidation, kudzivirira kusakara, kubatana kwewaya, kushanda kwemagetsi, kushanda zvakanaka kwekubatanidza, nezvimwewo. Gwaro iri richapa ongororo yakadzama yePCB inonyanya kushandiswa, zvakanakira uye zvisingakwanisike, uye gwara rekusarudza kupedzwa kwepamusoro kwezvishandiso zvakasiyana.

Mhedziso yeCommon PCB Surface Inopedza

Kune maviri makuru marudzi ePCB pamusoro pekupedzisira - simbi uye organic. Zvakajairika metallic kupera kunosanganisira:

• Hot Air Solder Leveling (HASL)
• Kunyudza Tin (Sn)
• Kunyudza Sirivha (Ag)
• Electroless Nickel Immersion Gold (ENIG)
• Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG)

Nepo zvakajairika organic kupera ndezvi:

• Organic Solderability Preservatives (OSP)
• Liquid Photoimageable Solder Masks (LPISM)

Metallic pamusoro pekupedzisira inogona kukamurwazve kuita yakafemerwazve senge HASL uye yakapfava inopera senge ENIG. Reflowed finishes zvinosanganisira kuisa solder pamapads, wozoyererazve kugadzira coating. Yakapfava inopedza inoshandisa electroplating kana kemikari deposition kupfekedza iyo PCB pamusoro nemarata esimbi.

Pazasi pane tarisiro yemhando yega yega yePCB pamusoro pekupedzisira:

Hot Air Solder Leveling (HASL)

HASL inoshandisa solder yakanyungudutswa paPCB pads, inozogadziriswa nemapanga emhepo inopisa. Mhedzisiro ndeye solder coating ye 1-70 μm pane pad pedhi. HASL inopa yakanakisa solderability uye ndiyo inodhura-inoshanda kupedzisa. Zvisinei, ine zvipingamupinyi zvakawanda:

• Iyo gobvu uye isina kuenzana dhipoziti inogona kutungamirira kune yakaderera gungano goho
• Solder masks inogona kukuvadzwa panguva yekugadzira bhodhi
• Haikodzere masimbi akanaka nekuda kwengozi dzekuvharisa
• Iyo yekupfeka inopera nekufamba kwenguva, ichideredza solderability

Kunyudza Tin (Sn)

Immersion tin inoisa chidimbu cherata (0.1-0.8 μm) nekunyudza maPCB mugaba rinopisa-based solution. Iyo tin coating inopa yakanakisa solderability paunenge uchitungamira-isina. Inodzivirirawo mhangura oxidation. Asi pane zvinonetsa pamusoro pekukura kwendebvu uye kusasimba kwekugera.

Kunyudza Sirivha (Ag)

Sirivha yekunyudza inosanganisira kunyudza maPCB mumhinduro yesirivheri kuti igadzire sirivha yakatetepa (0.1-0.3 μm) pamatehwe emhangura. Inopa yakanakisa solderability, conductivity uye corrosion resistance. Nekudaro, iyo coating inoshatisa nekufamba kwenguva. Iyo nzira inodawo kunyatsochengetedza bhati resirivha.

Electroless Nickel Immersion Gold (ENIG)

ENIG inzira yekugadzira mbiri ine electroless nickel (3-6 μm) yakaputirwa pekutanga, ichiteverwa neakatetepa kunyudza goridhe layer (0.05-0.15 μm). Iyo nickel layer inopa diffusion chipingamupinyi nepo goridhe ichipa yakanakisa ngura uye kupfeka kuramba. Asi ENIG inodhura. Kudzora ukobvu hwegoridhe layer kwakakosha zvakare.

Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG)

ENEPIG ndeye matatu-layer plating ine electroless nickel uye palladium layer yakawedzerwa pazasi pegoridhe rekunyudzwa. Iyo palladium inoshanda sechivharo chekudzivirira kudzivirira kupararira kwemhangura. Iyo zvakare inoderedza goridhe embrittlement nyaya dzinoonekwa muENIG. Nekudaro, mutengo wakakwira kupfuura ENIG.

Organic Solderability Preservatives (OSP)

OSP coatings ndiwo organic mafirimu anoshandiswa nekunyudza kana kumwaya maPCB ane organic komisheni ine azole heterocycles. Iyo yakaonda organic layer (0.1-0.2 μm) inodzivirira mhangura kubva kune oxidation uye inochengetedza solderability. OSP iri nyore kushandisa uye ine mutengo wakaderera maitiro. Zvisinei, inopa dziviriro shoma kana ichienzaniswa nesimbi.

Liquid Photoimageable Solder Masks (LPISM)

LPISM ndeye UV-inorapika solder masks anoita sechigarire organic coating paPCBs. Inopa insulation, makemikari uye abrasion kuramba apo ichirambidza solder kuyerera. LPISM inobvisa kudiwa kwechipiri conformal coatings. Asi zvinhu uye mari yekugadzira yakakwira zvakanyanya.

Makiyi Zvivakwa zveAkasiyana PCB Surface Inopedza

Kusarudzwa kwePCB pamusoro pekupedzisira kunokanganisa huwandu hwezvivakwa zvebhodhi. Pazasi pane kuenzanisa kweakakosha maitiro eakajairwa kupera:

Kugona Kutengesa: Kunyudza Sn neAg zvine mukana wakanyanya wekugona kutengesa. HASL neOSP isarudzo dzenguva pfupi.

Kuramba Kuora: Kunyudzwa Ag neAu zvinopa dziviriro yakanakisisa, zvichiteverwa neSn neNi layers.

Kuramba Kuoxidation: Kunyudzwa Ag neAu zvinodzivirira oxidation zvinobudirira. OSP ine kupokana kuri pakati nepakati.

Kuramba Kupfeka/Kukwesha: Mapendi esimbi akaomarara akadai seAu, Ag neNi-P anopa dziviriro yakanakisisa yekupfeka.

Kubatana kweWaya: Nzvimbo dzeNi nePd dzinobvumira kubatana kwewaya kwemhando yepamusoro.

Kunyunguduka/Kunyunguduka kweSolder: Ni nePd zvinoshanda sezvipingamupinyi zvekupararira kwemvura kuti zvideredze kunyunguduka kwemvura.

Mutengo: OSP neHASL ndidzo dzinonyanya kudhura. ENIG, ENEPIG neAg ndidzo sarudzo dzepamusoro-soro.

Kuungana: HASL inogona kukonzera matambudziko nekubatanidzwa kusina mutobvu. ENIG, ENEPIG naAg zvinopa goho guru pakuungana.

Saka pane nguva dzose kutengeserana-offs yekufunga maererano nezvinodiwa zvekushandisa uye zvimhingamipinyi zvebhajeti.

Nhungamiro Yekusarudza PCB Surface Inopedza

Heano mamwe akakosha nhungamiro yekusarudza yakakodzera PCB pamusoro pekupedzisira:

• Lead vs Lead-Yemahara - Inotungamira-ine HASL ichiri kushandiswa zvakanyanya, nepo kunyudza Sn kana Ag iri inotungamira-yemahara sarudzo.
• Yakanaka Pitch Zvikamu - Kune yakanaka pitch ICs, sarudza yekunyudza simbi coating kudzivirira bhiriji.
• Goridhe Wire Bonding - ENIG kana ENEPIG inobvumira yakavimbika goridhe waya kubatanidza.
• Corrosion Resistance - Kana nharaunda ichikuvadza zvakanyanya, sirivha kana goridhe kunyudzwa ndiyo sarudzo dzakanakisa.
• Kushanda Tembiricha - Pakutonhora kwakanyanya, Sn whisking uye Ni embrittlement inogona kuitika. Ag kana Au anoshanda zvirinani.
• Kushanda Frequency - Kune microwave neRF mabhodhi, kunyudzwa kwesirivha kunopa yakanakisa conductivity.
• Flex/Rigid-Flex PCBs - Mabhodhi matete uye anochinjika anoda OSP kana LPISM kupera.
• Component Density - Kune yakakwira component densities, Ni/Pd kana Ni/Au inokurudzirwa.
• Component Termination - ENIG inoshanda zvakanaka negoridhe-yakapfatwa inotungamira. Sn, Ag uye OSP suit tin-based kumiswa.
• Via-in-Pad Dhizaini - A Ni layer inobatsira kudzivirira solder wicking kupinda vias.
• Hermetic Kuisa Chisimbiso - Vanotengesazve vatengesi seHASL vanobvumira hermetic chisimbiso chezvikamu.
• Mutengo - Zvemaprototypes, mavhoriyamu akaderera kana mabhodhi anoona mutengo, HASL uye OSP ndiyo yakachipa sarudzo.
• Nguva Yekutungamira -Kunyudzwa Sn uye Ag inopa nekukurumidza kutendeuka pamusoro peENIG kana ENEPIG.

Saka iyo yekupedzisa kwepamusoro inopesvedzera zvese kubva kune soldering, bonding, assembly, reworkability kusvika kurefu-refu kuvimbika kwePCBs munzvimbo dzavanofungidzira dzekushanda.

Mhedzisiro yePCB Surface Inopedzisa pane Soldering Matanho

PCB pamusoro pekupedzisira inoita basa rakakosha mukutengesa maitiro, kukanganisa reflow soldering, wave soldering, uye rework. Munguva yekudzokorodza solder, inopera seOSP, kunyudza Ag, Sn, uye Au/Ni inosimudzira kunyorova, nepo HASL ichigona kukonzera kusakwana solder paste coalescence. Kune wave soldering, kunyudza kupera kunosarudzwa kudzivirira nyaya dzekutengesa, kunyangwe mamwe machemistries anogona kurwisa Ag kana Sn coatings. Mamiriro ekuburitsa epaste paste panguva yekudhinda anosiyana zvichienderana nepamusoro pekupedzisira, aine akatsetseka anopedzisa seAu neAg achigonesa kuburitsa paste nyore kana zvichienzaniswa nekukasira kupedzisa seHASL.

Smooth nzvimbo dzinopa mabhenefiti mukuiswa kwechikamu, ichipa yakanyanya kurongeka uye kudzokororwa kwekutora nenzvimbo maitiro. Pamusoro pezvo, nzvimbo dzakapfava, girazi-sekupedzisa senge Ag neAu inobvumira kutarisisa kwemaziso kuri nyore, kunowedzera kutarisika. Nekudaro, kana zvasvika pakugadzirisazve, kumwe kupedzisa kunogona kuunza matambudziko. Kupfeka kweNi kunogona kutungamira mukusimudza padhi, kunyudza Ag kunogona kukonzera kupera, uye ENIG inogona kusangana neAu dissolution.

Kunzwisisa hurema hwekutengesa hune hukama neakasiyana ekupedzisira kupera, sekubata neHASL kana kuvharika ne ENIG, kwakakosha pakugadzirisa maitiro ekutengesa. Nekusarudza iyo yakakodzera yepamusoro pekupedzisira, PCB vagadziri vanogona kukwidziridza mashandiro ekutengesa, kuvandudza goho, uye ive nechokwadi chekuvimbika kwekubatanidzwa kwavo kwakatengeswa.

Kuvimbika Kufunga Kweakasiyana Surface Inopedzisa

Kupera kwepamusoro kunokanganisa kuvimbika kwenguva refu kwemajoini ekutengesa uye kuramba kwavo kutadza nzira:

• Intermetallic Compound (IMC) Magadzirirwo: Yakaonda ImAg kuumbwa kunovandudza kuvimbika. Yakakora Cu-Sn IMCs ine Sn coating haidiwe.
• Leaching uye Dissolution: Ni uye Pd vanoita sezvipingamupinyi zvinokanganisa kuderedza pad leaching kuita solder.
• Corrosion: Ag, Au uye Ni coatings inopa yakanyanya kunaka corrosion kuramba. Acidic flux masara anogona achiri kurwisa Ag uye Sn zvakadaro.
• Kukura kweDendrite: Electroless inopedza seNi uye Ag inowanzoita dendritic kukura zvichienderana ne electroplated deposits.
• Thermal Cycling: Pedzisa kutyoka pad pad interfaces kunetseka, kunyanya nebrittle intermetallics. Ductile Au naAg vanoshingirira kuchovha bhasikoro zviri nani.
• Electromigration: Inononoka kutakurwa kweerekitironi kunoitika pakatarisana pakati pe solder uye mamwe mapedzi (semuenzaniso Ni), ichibatsira electromigration kuramba.

Saka iyo yakakwana kupedzisa inoderedza ukobvu hweIMC, inhibits leaching, inomira corrosion, inodzivirira kupararira, inoderedza voiding sensitivity, inodzivirira dendrite kuumbwa, uye inochengetedza kupisa bhasikoro. Izvi zvinovimbisa zvakanyanya solder kubatana kutendeseka uye kuvimbika pasi pekushanda kwemunda.

Zvakajairwa Kukanganisa uye Kutadza kwakabatana neSurface Finishes

Izvo zvakakoshawo kuziva nezve hurema hunogona kuunzwa nePCB pamusoro pekupedzisira panguva yekugadzira, kusangana uye sevhisi:

• Dewetting - Ag akaturikidzana akabatwa nesarufa kana kusvibiswa anogona kukonzera kushoma solder kupararira.
• Makomba uye Voids - Kunyudzwa Ag inowanzoita gomba. ENIG inogona kunge iine interfacial voids.
• IMC Spiking - Yakakora Cu-Sn intermetallics inogona spike kuita yakawanda solder neSn coating.
• Kubhururuka - Kuchovha bhasikoro kunogona kukonzera kupera kubhururuka pamapedhi emafirimu akaita seENIG uye Ag.
• Pink Ring - Iyo yepinki chromate yakasara yakasara kubva ku ENIG etching inogona kukonzera solderability nyaya.
• Goridhe Embrittlement - Au akakora kupfuura 0.5 μm muENIG anogona kuita brittle.
• Solder Leaching - Ni layer inoshanda sechipinganidzo chekuparadzira kudzivirira pad leaching neCu-dissolving solders.
• Matinji Whiskers - Mabhii machira anogona kugadzira ndebvu nekufamba kwenguva, zvichiita njodzi yekushomeka kwemagetsi.

Saka kuongorora maPCB ehuvepo hwekuremara kwakadaro kwakakosha kuti udzivise kutadza kwemunda kune chekuita nekupedza kwepamusoro. Izvi zvinobvumira matambudziko ekutevera kune chaakonzera - ingave nyaya dzekugezera, kubata kwebhodhi kana kuratidzwazve.

mhedziso

Kazhinji, kusarudza PCB surface finish yakanakisisa kunosanganisira kufunga nezvezvinhu zvakawanda zvakaita semutengo, nguva yekutungamira, fine pitch assembly, mamiriro ekushanda, uye zvinodiwa zvekuvimbika. Kupera kwepamusoro kwakasarudzwa kunokanganisa nhanho yega yega yePCB production cycle, kubva pakugadzira kusvika pakunamira, kuongorora, kuunganidza, uye kushandiswa kwebhodhi kwenguva refu. Nokudaro, zvakakosha kuenzanisa kutengeserana pakati pezvinhu zvepamusoro, kugadzirwa, uye kuvimbika pakusarudza kwakakodzera finish. Chinyorwa chino chakapa ongororo yesarudzo dzakakurumbira dzekupera uye mhedzisiro yadzo, zvichipa simba vagadziri vePCB kuti vaite sarudzo dzakangwara uye kuwedzera mhando, goho, kushanda kwekubatanidza, uye kuvimbika kwekushanda kwemabhodhi avo akagadzirwa. Muchinyorwa chinotevera, tichaongorora zvakadzama mamiriro chaiwo ekushandisa uye kuongorora zvakanakira nekuipira kwePCB surface finish dzakasiyana-siyana.

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