The general surface treatments ye PCB zvinosanganisira kumwaya marata, OSP, kunyudzwa kwegoridhe, zvichingodaro. “Pamusoro” pano zvinoreva nzvimbo dzekubatanidza paPCB dzinopa kubatanidza kwemagetsi pakati pezvinhu zvemagetsi kana mamwe masisitimu uye dunhu rePCB, semapedhi. Kana yekubatanidza nzvimbo. Iyo solderability yemhangura isina chinhu pachayo yakanaka kwazvo, asi iri nyore kuita oxidize kana yaiswa mumhepo, uye zviri nyore kusvibiswa. Ichi ndicho chikonzero PCB inofanirwa kurapwa pamusoro.

1. Mwaya tin (HASL)

Iko kune michina ine perforated inotonga, wave soldering ndiyo yakanakisa solder nzira. Iko kushandiswa kwekupisa-mhepo solder leveling (HASL, Kupisa-mhepo solder leveling) tekinoroji yekurapa kwepamusoro inokwana kuzadzisa zvinodiwa nehurongwa hwekutengesa wave. Ehe, kune zviitiko zvinoda kusimba kwepamusoro (kunyanya kubatana kwekubatanidza), electroplating ye nickel / goridhe inowanzoshandiswa. . HASL ndiyo hombe yekurapa tekinoroji inoshandiswa pasi rese, asi kune matatu makuru masimba ekutyaira anotyaira indasitiri yezvemagetsi kuti itarise mamwe matekinoroji eHASL: mutengo, maitiro matsva anodiwa uye zvisingadhure zvinodiwa.

Kubva pamutengo wekuona, zvinhu zvakawanda zvemagetsi zvakadai senharembozha uye makomputa emunhu ari kuita zvinhu zvakakurumbira zvevatengi. Chete nekutengesa nemutengo kana mitengo yakaderera tinogona kusakundika munzvimbo inotyisa yemakwikwi. Mushure mekuvandudza tekinoroji yegungano kuSMT, PCB pads inoda kudhindwa kwescreen uye reflow soldering maitiro panguva yegungano. Panyaya yeSMA, iyo PCB pamusoro pekurapa maitiro ichiri kushandisa iyo HASL tekinoroji pakutanga, asi sezvo michina yeSMT ichiramba ichidzikira, mapadhi uye kuvhurwa kwestencil kwave kudiki, uye zvinokanganisa zveHASL tekinoroji zvakafumurwa zvishoma nezvishoma. Mapadhi akagadziriswa neHASL tekinoroji haana kufuratira zvakakwana, uye iyo coplanarity haigone kusangana nezvinodiwa zvemaitiro epadhi-pitch pads. Zvinetso zvemhoteredzo kazhinji zvinonangidzira pamusoro pezvinokonzeresa kukanganiswa kwemutobvu pane zvakatipoteredza.

2. Organic Solderability Protective Layer (OSP)

Organic solderability preservative (OSP, Organic solderability preservative) ndeye organic coating inoshandiswa kudzivirira oxidation yemhangura isati yatengeswa, ndiko kuti, kuchengetedza kutengwa kwePCB pads kubva mukukuvadzwa.

Mushure mekunge PCB yabatwa neOSP, chidimbu chakaonda chinoumbwa pamusoro pemhangura kudzivirira mhangura kubva kune oxidation. Ukobvu hweBenzotriazoles OSP hunowanzoita 100 A°, ukuwo hukobvu hweImidazoles OSP hwakakora, kazhinji 400 A°. OSP firimu iri pachena, hazvisi nyore kusiyanisa kuvapo kwayo neziso rakashama, uye zvakaoma kuona. Munguva yegungano rekuita (reflow soldering), iyo OSP inonyungudutswa nyore nyore mune solder paste kana acidic Flux, uye panguva imwechete iyo inoshanda mhangura inoiswa pachena, uye pakupedzisira Sn / Cu intermetallic komputa inoumbwa pakati pezvikamu nemapadhi. Naizvozvo, OSP ine hunhu hwakanaka kwazvo kana ichishandiswa kurapa welding pamusoro. OSP haina dambudziko rekusvibiswa kwemutobvu, saka inochengetedza zvakatipoteredza.

Kugumira kweOSP:

①. Sezvo OSP iri pachena uye isina ruvara, zvakaoma kuongorora, uye zvakaoma kusiyanisa kana PCB yakaputirwa neOSP.

② OSP pachayo yakavharwa, haifambisi magetsi. OSP yeBenzotriazoles inenge yakatetepa, iyo inogona kunge isingakanganisi kuedza kwemagetsi, asi kune OSP yeImidazoles, firimu rinodzivirira rakaumbwa rinenge rakakora, izvo zvichakanganisa kuedza kwemagetsi. OSP haigone kushandiswa kubata magetsi ekubata nzvimbo, senge keyboard pamusoro pemakiyi.

③ Munguva yeWelding process yeOSP, yakasimba Flux inodiwa, kana zvisina kudaro iyo inodzivirira firimu haigone kubviswa, izvo zvinozotungamira kune welding kuremara.

④ Panguva yekuchengetedza, nzvimbo yeOSP haifanirwe kuratidzwa kune acidic zvinhu, uye tembiricha haifanire kunge yakanyanya kukwirira, zvikasadaro OSP inoshanduka.

3. Kunyudza goridhe (ENIG)

Nzira yekudzivirira ye ENIG:

Ni/A yakaputirwa pamusoro pemhangura nenzira yemakemikari. Ukobvu hwekuiswa kwemukati weNi hunowanzo 120 kusvika 240 μin (anenge 3 kusvika 6 μm), uye ukobvu hwekuisa kwekunze kweAu kutetepa, kazhinji 2 kusvika 4 μinch (0.05 kusvika 0.1 μm). Ni inoumba chipingamupinyi chinodzivirira pakati pe solder nemhangura. Munguva yekushambadzira, iyo Au iri kunze inokurumidza kunyunguduka mune solder, uye solder uye Ni ichagadzira Ni / Sn intermetallic compound. Iyo goridhe yekuisa kunze ndeyekudzivirira Ni oxidation kana passivation panguva yekuchengetera, saka iyo goridhe yeplating layer inofanirwa kuve yakakora zvakakwana uye ukobvu haufanirwe kunyanyotetepa.

Kunyudza goridhe: Mukuita uku, chinangwa ndechekuisa goridhe rakatetepa uye rinoenderera mberi rekudzivirira. Ukobvu hwegoridhe guru hahufanire kunge hwakanyanya kukora, kana zvikasadaro majoini ekutengesa anozonyanya brittle, izvo zvinokanganisa zvakanyanya kuvimbika kwewelding. Senge nickel plating, kunyudza goridhe ine tembiricha yekushanda yakanyanya uye nguva yakareba. Munguva yekunyudza, maitiro ekutamisa achaitika-pamusoro pe nickel, goridhe inotsiva nickel, asi kana kutama kwasvika pane imwe nhanho, kusimuka kwekuita kunongomira. Ndarama ine simba rakawanda, abrasion resistance, high temperature resistance, uye haisi nyore kuisa oxidize, saka inogona kudzivirira nickel kubva kune oxidation kana passivation, uye yakakodzera kushanda mune yakakwirira-simba maapplication.

Iyo PCB yepamusoro inobatwa ne ENIG yakanyanya kupfava uye ine yakanaka coplanarity, inova ndiyo yega inoshandiswa pakubata kumeso kwebhatani. Kechipiri, ENIG ine yakanakisa solderability, goridhe rinokurumidza kunyunguduka mune yakanyungudutswa solder, nekudaro ichifumura nyowani Ni.

Zvinogumira zve ENIG:

Maitiro eENIG akanyanya kuomarara, uye kana iwe uchida kuwana mhedzisiro yakanaka, iwe unofanirwa kunyatso kudzora maitiro ekuita. Chinhu chinonyanya kunetsa ndechekuti iyo PCB inobatwa ne ENIG inogara kune mapedhi matema panguva yeENIG kana soldering, izvo zvinova nenjodzi yekukanganisa kuvimbika kwemasoja majoini. Nzira yechizvarwa chedhisiki dema yakaoma zvikuru. Inoitika pakusangana kweNi negoridhe, uye inoratidzwa zvakananga seyakanyanya oxidation yeNi. Goridhe rakawandisa richava embrittle majoini solder uye kukanganisa kuvimbika.

Imwe neimwe nzira yekurapa yepamusoro ine yayo yakasarudzika maficha, uye chiyero chekushandisa chakasiyanawo. Maererano nekushandiswa kwemapuranga akasiyana, zvinodiwa zvakasiyana-siyana zvekurapa kwepamusoro zvinodiwa. Pasi pekudzivirirwa kwemaitiro ekugadzira, isu dzimwe nguva tinoita mazano kune vatengi zvichienderana nehunhu hwemabhodhi. Chikonzero chikuru kuve nekugadziriswa kwepamusoro kwepamusoro kunoenderana nekushandiswa kwechigadzirwa chemutengi uye kugona kwekambani. s Sarudzo.