Ukushayela Okujulile Okulawulwa Ekwenziweni Kwe-PCB: Ukubhola Emuva kuyini ukubhola emuva ku-pcb?

I-backdrilling emabhodini ezintambo anezinhlaka eziningi kuyinqubo yokukhipha i-stub ukuze kukhiqizwe i-vias, okuvumela amasignali ukuthi asuke kolunye ungqimba lwebhodi aye kolandelayo. (Ama-stubs azodala ukucabangela, ukuhlakazeka, ukubambezeleka, nezinye izinkinga phakathi nokudluliswa kwesignali, okuzokwenza ukuthi isignali ihlanekezelwe.) Ukubhoboza ekujuleni okulawulwayo kudinga ikhono eliyinkimbinkimbi.Ukwenza amabhodi esekethe ezendlalelo eziningi, afana namabhodi ezendlalelo eziyi-12, kudinga ukuxhuma isendlalelo sokuqala kungqimba lwesishiyagalolunye. Ngokuvamile, sibhoboza izimbobo kanye kuphela ngaphambi kokuhlanganisa i-vias. Isitezi sokuqala kanye nesitezi se-12 kuxhunywe ngokushesha. Eqinisweni, isitezi sokuqala sidinga nje ukuxhumeka esitezi sesishiyagalolunye. Njengoba zingekho izintambo ezixhumanisa i-10 nele-12, zifana nezinsika. Le kholomu inomthelela endleleni yesiginali futhi ingase ibeke engcupheni isiginali yesignali yokuxhumana. Ngakho-ke, imbobo yesibili ibhorekile ngakolunye uhlangothi lwekholomu eyengeziwe (okubizwa ngokuthi i-STUB embonini).

Ngenxa yalokho, kwaziwa ngokuthi ukubhola emuva, nokho ngokuvamile akuhlanzeki kangako kunokubhola ngoba isinyathelo esilandelayo sizokhipha ithusi ngogesi kanti ithiphu lokubhoboza libukhali. Ngakho-ke sizoshiya iphuzu elincane kakhulu; ubude bale STUB esele baziwa njengevelu engu-B, futhi ngokuvamile isukela ku-50 kuye ku-150 UM.

Ubuchwepheshe be-PCB bokubhola emuva

Ngenxa yesidingo sokunciphisa ukulahlekelwa kwesignali kuzinhlelo zokusebenza zefrikhwensi ephezulu, imbobo edlulayo exhuma izendlalelo iyadingeka ukuze isignali igeleze njengoba isuka kwenye isiya kwenye. Kunconywa ukuthi kukhishwe ithusi elinqwabelene kule mbobo kulolu hlelo lokusebenza ngoba lisebenza njengothi futhi lithinta ukuhanjiswa uma isignali izogeleza isuka kungqimba lokuqala iye kweyesibili ebhodini lezindlalelo ezingama-20, isibonelo.

Ukuze sithole ukuzinza okukhulu kwesignali, sikhipha ithusi "elidlulele" embobeni sisebenzisa i-back-drilling (ukujula okulawulwayo ku-axis engu-z). Umphumela omuhle uwukuba i-stub (noma "eqile" yethusi) ibe mfushane ngangokunokwenzeka. Ngokuvamile, usayizi wokubhoboza ngemuva kufanele ube ngu-0.2mm mkhulu kunendlela ehambisanayo.

Iinqubo ye-backdrill isusa ama-stubskusuka emigodini ecwecwe (nge-vias). Iziqu azinasidingo/izingxenye ezingasetshenzisiwe ze-vias, enwebeka kakhulu kunesendlalelo sangaphakathi sokugcina esixhunyiwe.
Ama-stubs angaholelaukucabanga, kanye neukuphazamiseka kwamandla, inductivity kanye ne-impedance. Lawa maphutha angaqhubeki aba bucayi ngokwenyuka kwesivinini sokusabalalisa.
Izindiza ezingemuvafuthi Aminyene Amabhodi Esifunda Aphrintiwe ikakhulukazi, angakwazi ukubekezelaukuphazamiseka kobuqotho besignali okubalulekilengama-stubs. Ngoba High Frequency PCBs(isb. nge-Impedance control), ukusetshenziswa kokuhlehla emuva, kanye nokusetshenziswa kweabangaboni futhi bangcwatshwe vias, ingaba yingxenye yesixazululo.
I-Backdrill ingasetshenziswa kunoma yiluphi uhlobo lwebhodi lesifundalapho ama-stubs adala ukuwohloka kobuqotho besignali, ngomklamo omncane nokucatshangelwa kwesakhiwo. Ngokuphambene, uma usebenzisa i-blind vias, i-aspect ratio kufanele igcinwe engqondweni.

Izici ze-PCB zokubhola emuva

Izinzuzo Back Drilling

● Nciphisa ukuphazamiseka komsindo & jitter deterministic;

● Thuthukisa ubuqotho besignali;

● Ukunciphisa ukujiya kwendawo;

● Yehlisa ukusetshenziswa kwe-vias egqitshiwe futhi eyimpumputhe futhi yehlise ubunzima bokukhiqizwa kwe-PCB;

● Izinga lephutha lebhithi eliphansi (BER);

● Ukunciphisa isignali kancane ngokumatanisa okuvimbele okuthuthukisiwe;

● Umklamo omncane nomthelela wesakhiwo;

● Ukwenyuka komkhawulokudonsa wesiteshi;

● Amazinga edatha anyusiwe;

● ukukhishwa kwe-EMI/EMC kwehle kusukela ekugcineni;

● Ukwehliswa kwenjabulo yezindlela ze-resonance;

● Yehlisiwe ngokusebenzisa-kuya-nge-crosstalk;

● Izindleko eziphansi kunama-laminations alandelanayo.

Ububi Bokubhoboza Emuva

Amasignali aphezulu avame ukuba nezinkinga ezingase zixhunywe ekusetshenzisweni kancane ngama-stubs. Ake sibhekisise izinkinga ezimbalwa nge-stubs.

I-Jitter Deterministic: 
Womabili amawashi anesikhathi, futhi inani lephutha lesikhathi libizwa ngokuthi i-jitter. I-jitter evimbelayo yilokho okwaziwa njengokujwayelekile (okungukuthi, okulinganiselwe) ukuguqulwa kwesikhashana.

Ukuncishiswa kwesignali:
Uma umsindo uncishisiwe, ukuqina kwawo kuyehla futhi ishayela libe buthakathaka.

Imisebe evela ku-EMI:

I- via stub ingasetshenziswa njengothi, olukhipha imisebe ye-EMI.

Izici ezijwayelekile 

● Ikakhulukazi amabhodi aqinile ngemuva;

● Ivamise kusetshenziswa izendlalelo eziyi-8 noma ngaphezulu;

● Ugqinsi lwebhodi lungaphezu kuka-2.5mm;

● Usayizi omncane wokubamba ngu-0.3mm;

● I-Backdrill inkulu ngo-0.2mm kune-vias;

● Ukubekezelela ukujula kwe-backdrill+/-0.05MM.

Hlobo luni lwe-PCB oludinga ukubhola emuva?

Ngokuvamile, izimbobo zebhodi le-PCB zibhodlozwa ebhodini (kusuka phezulu kuye phansi). Uma umkhondo oxhumanisa izimbobo useduze nongqimba olungaphezulu (noma ungqimba olungezansi), kuzoholela ekuhlukanisekeni kwe-stub embobeni yesixhumanisi soxhumano lwe-PCB, okuzothinta ikhwalithi yesiginali futhi kubangele ukuboniswa. Izimpawu ezihamba ngesivinini zithinteka kakhulu yilo mphumela.

Ukuze uthole ikhwalithi ephezulu yokudluliswa kwesignali, ngokuvamile kuyaqondwa ukuthi ithrekhi yesifunda ebhodini le-PCB ne-Signals yayo ngenani elingaba ngu-1Gbps idinga ukucatshangelwa ukuthi ihlanganisa ukuklama kwe-back-drill. Yiqiniso, ukuklama imigqa yokuxhumana enesivinini esikhulu kudinga ubunjiniyela besistimu futhi akuqondile njengoba kungase kubonakale. Uma izixhumanisi zokuxhumanisa isistimu zingezide kakhulu noma amandla okushayela kwe-chip aqine ngokwanele, ikhwalithi yesiginali ingase ingabi naphutha ngaphandle kokubhola emuva. Ngakho-ke, ukulingisa isixhumanisi soxhumano lwesistimu kuyindlela enembe kakhulu yokunquma ukuthi i-back-drill iyadingeka noma cha.

Ungase uqaphele ukuthi, ngaphezu kokusebenzisa ubuchwepheshe bokubhola emuva, izindlela ezihlukahlukene zokwakha zingase zisetshenziswe ukunciphisa noma ukwandisa ubude be-stub. Lokhu kufaka phakathi izinhlelo ezihlukene zokupakisha, lapho ukulandelelwa kwethrekhi yesekethe kuhanjiswa kuzendlalelo eduze nasekupheleni kwe-stub, izimbobo ze-laser-drilled vias (microvias), noma izimbobo eziyimpumputhe nezigqitshiwe. Ukwengeza, njengoba kusetshenziswa ezinye izindlela ukuze kuncishiswe ukubonakaliswa kwesignali kumabhodi wefrikhwensi ephezulu (ngaphezulu kuka-3GHz), ukubhola emuva akudingekile.

Kodwa-ke, lezi zindlela azihlali zisebenza endaweni yokukhiqiza kanye nezindleko zokunciphisa ukulahlekelwa kwesignali kuma-PCB amaningi aphakeme kakhulu noma izindiza ezingemuva/ezindizeni ezimaphakathi. Ngakho-ke, okuwukuphela kwesinqumo esisebenzayo ukuphinda ubhobole i-stub ngaphandle. Uma izimbobo ze-vias eziyizimpumputhe zingeyona inketho, ukubhola emuva kuba yimpoqo kumabhodi wefrikhwensi ephezulu (ngaphezu kuka-1GHz ngaphakathi kwe-3GHz).

Futhi njengoba i-PCB inezendlalelo eziningi, ezinye izimbobo azikwazi ukuklanywa njengezimbobo eziyizimpumputhe (isibonelo, ku-PCB enezingqimba eziyi-16, ezinye ngezimbobo kufanele zixhumeke kungqimba 1 kuya ku-10 kanti enye ngembobo kufanele ixhume izendlalelo 7 kuya ku-16; lo mklamo awufanele izimbobo eziyizimpumputhe kodwa ufanelekile ukubhola emuva).

Ungayenza kanjani i-PCB yokubhola emuva?

Inqubo Yokubhola Emuva

1.Ukuthola imbobo yokuqala yokumba, sebenzisa imbobo yokubeka ku-PCB enikeziwe.

2.Ngaphambi kokucwenga, sebenzisa ulwelwesi olomile ukuze uvale imbobo yokuma.

3.Powder imbobo ngethusi ukuze udale isifunda somhlahlandlela.

4.Dala isithombe sangaphandle ku-PCB.

5.Ngemva kokudala iphethini yesendlalelo sangaphandle, ibhodi lesithombe lizosetshenziswa ku-PCB. Ngaphambi kwale nqubo, kubalulekile ukuvala imbobo yokubeka ngolwelwesi olomile ngaphambi kokuqala le nqubo.

6.Sebenzisa izimbobo zokumba zokuqala ukuze uqondise ukubhola emuva, bese usebenzisa i-drill bit ukuze ubhoboze izimbobo ezifakwe ugesi ezidinga le nqubo.

7.Ngemva kokubhola kokugcina, ibhodi lidinga ukuhlanzwa ukuze kuqedwe noma yikuphi ukubhola okungaba khona okusele.

8.Ngemva kokuba ibhodi seliqinisekisiwe futhi nobuqotho besignali buthuthukisiwe, qaphela ukuthi umsebenzi wokumba wenziwa ngendlela efanele yini.

Hlola ama-Back Drills 

Uma umzila usuqediwe, kufanele siqinisekise ukuthi ama-drill angemuva amiswe kahle. Ukuze uqinisekise lokhu, vula zonke izendlalelo. Uzobona ukuthi rim ye-vias inemibala emibili kuyo. Isendlalelo sokuqala noma sokuqala siboniswa ngokubomvu, kanti isendlalelo sokugcina siboniswa ngombala oluhlaza okwesibhakabhaka. Kulula ukutshela ama-vias ambozwe ngemuva ngaphandle kwamanye. Ama-vias angemuva kuphela abonakala ngemibala emibili.

Chofoza Ithebula le-Drill ngemva kokukhetha indawo kumenyu enkulu ukuze uthole ukuthi mangaki ama-Vias, PTH, namanye ama-troll enziwe.

Ubunzima bezobuchwepheshe benqubo yokumba emuva.

1.Ukulawula ukujula kokumba emuva
Ukuze kucutshungulwe okunembile kwe-vias eyimpumputhe, ukulawula ukujula kokumba emuva kubalulekile. Ukubekezelela ukujula kokumba emuva kuthonywa kakhulu ukunemba kwemishini yokumba emuva kanye nokubekezelela ukushuba okuphakathi. Ukunemba kokubhola emuva, nokho, kungaphinde kuthinteke okuguquguqukayo kwangaphandle njengokumelana nokubhoboza, i-engeli yethiphu yokubhoboza, umphumela wokuxhumana phakathi kwebhodi lekhava nedivayisi yokulinganisa, kanye ne-warpage yebhodi. Ukuze uthole imiphumela emihle kakhulu futhi ulawule ukunemba kokumba emuva, kubalulekile ukukhetha izinto nezindlela zokumba ezifanele ngesikhathi sokukhiqiza. Abaklami bangaqinisekisa ukudluliswa kwesignali yekhwalithi ephezulu futhi bagweme izinkinga zesignali yobuqotho ngokuphatha ngokucophelela ukujula kokumba emuva.

2.Ukunemba kokunemba kwe-Back
Ukulawula ukubhola emuva okunembile kubalulekile ekulawuleni ikhwalithi ye-PCB ezinqubweni ezilandelayo. Ukubhola emuva kuhlanganisa ukubhola kwesibili okusekelwe kububanzi bomgodi wokuqala, futhi ukunemba kokubhola kwesibili kubalulekile. Ukunemba kokushayisana kwesibili kokumba kungase kuthonywe inani lezinto eziguquguqukayo, njengokunwetshwa kwebhodi nokufinyela, ukunemba komshini, nezindlela zokumba. Kubalulekile ukwenza isiqiniseko sokuthi inqubo yokumba emuva ilawulwa ngokunembile ukuze kuncishiswe amaphutha futhi kugcinwe ukudluliswa kwesignali nobuqotho.

Isinyathelo esibaluleke kakhulu nesiyinselele ukubhola ngoba ngisho iphutha elincane lingase libangele umonakalo omkhulu. Ngaphambi kokufaka i-oda, kufanele ucabangele amakhono omenzi we-PCB.I-Richfulljoy inikeza amabhodi abhoboziwe emuva ngamanani athengekayo futhi igxile kakhulu ekuhlanganiseni kwesibonelo se-PCB. Izinzuzo zethu zihlanganisa izikhathi ezisheshayo zokulethwa nokuthembeka okuphezulu.I-Richfulljoy, umkhiqizi we-PCB owaziwayo e-China, unalo lonke ulwazi namakhono adingekayo ukuze akusize. Uma uneminye iziphakamiso zenhlangano ye-PCB noma i-prototype, sicela usithinte: mkt-2@rich-pcb.com