In high-speed HDI PCB uyilo, ngoyilo yinto ebalulekileyo. Iqulathe umngxuma, indawo yepadi ejikeleze umngxuma, kunye nendawo esecaleni yomaleko AMANDLA, ahlala ahlulahlulwe abe ziintlobo ezintathu: imingxuma eyimfama, imingxuma engcwatyiweyo kunye nemingxuma. Kwinkqubo yoyilo lwe-PCB, ngohlalutyo lwe-parasitic capacitance kunye ne-parasitic inductance ye-vias, ezinye izilumkiso kuyilo lwe-PCB enesantya esiphezulu ziyashwankathelwa.

Okwangoku, uyilo lwePCB olunesantya esiphezulu lusetyenziswa kakhulu kunxibelelwano, iikhompyuter, imizobo kunye nokusetyenzwa komfanekiso kunye neminye imimandla. Lonke uyilo oluphezulu lwexabiso elongezelelweyo lwemveliso ye-elektroniki lulandela iimpawu ezifana nokusetyenziswa kwamandla aphantsi, imitha ye-electromagnetic ephantsi, ukuthembeka okuphezulu, i-miniaturization, kunye nobunzima obulula. Ukuze kuphunyezwe ezi njongo zingasentla, ngoyilo yinto ebalulekileyo kuyilo lwePCB olunesantya esiphezulu.

1. Nge
IVia yinto ebalulekileyo kuyilo lwePCB enamaleko amaninzi. I-A via ubukhulu becala yenziwe ngamacandelo amathathu, enye ngumngxuma; enye yindawo yephedi ejikeleze umngxuma; kwaye eyesithathu yindawo esecaleni yomaleko WAMANDLA. Inkqubo yokudlula umngxuma kukucwenga umaleko wesinyithi kumphezulu wecylindrical kumngxuma wodonga lomngxunya ngokubekwa kweekhemikhali ukudibanisa ifoyile yobhedu ekufuneka idityaniswe kumaleko aphakathi, kunye namacala aphezulu nasezantsi umngxuma wenziwa kwiipads eziqhelekileyo Ubume bunokudibaniswa ngokuthe ngqo kunye nemigca emacaleni angaphezulu nangaphantsi, okanye angaxhunywanga. I-Vias inokudlala indima yoxhumo lombane, ukulungiswa okanye ukubeka izixhobo.

IiVias ngokubanzi zohlulwe zibe ziindidi ezintathu: imingxuma eyimfama, imingxuma engcwatyiweyo kunye nemingxuma.

Imingxuma eyimfama ibekwe kwindawo ephezulu nangaphantsi yebhodi yesekethe eprintiweyo kwaye inobunzulu obuthile. Zisetyenziselwa ukudibanisa umgca womphezulu kunye nomgca wangaphakathi ongaphantsi. Ubunzulu bomngxuma kunye nobubanzi bomngxuma ngokuqhelekileyo akudluli umlinganiselo othile.

Umngxuma ongcwatywayo ubhekiselele kumngxuma wokudibanisa obekwe kwinqanaba elingaphakathi lebhodi yesekethe eprintiweyo, engadlulisi kumphezulu webhodi yesekethe.

vias Blind kunye vias wangcwatywa zombini ibekwe umaleko engaphakathi kwibhodi yesekethe, nto leyo igqityezelwe yinkqubo-umngxuma ukwenza inkqubo phambi lamination, kunye nezaleko eziliqela yangaphakathi ukuze kugqithe ngexesha lokusekwa vias.

Ngemingxuma, edlula kuyo yonke ibhodi yesekethe, ingasetyenziselwa ukudibanisa kwangaphakathi okanye njengenxalenye yokubeka indawo yokubeka umngxuma. Ekubeni ngokusebenzisa imingxunya kulula ukuphumeza kwinkqubo kunye neendleko eziphantsi, iibhodi zesekethe eziprintiweyo ngokubanzi zisebenzisa ngemingxunya.

2. I-Parasitic capacitance ye-vias
Indlela edlulayo ngokwayo inamandla eparasitic emhlabeni. Ukuba ububanzi bomngxuma wokwahlulwa kumhlaba wendlela yi-D2, ububanzi be-pad yi-D1, ubukhulu be-PCB yi-T, kunye ne-dielectric engaguqukiyo ye-substrate yebhodi ngu-ε, ngoko I-parasitic capacitance indlela iyafana ne:

C =1.41εTD1/(D2-D1)

Impembelelo ephambili ye-parasitic capacitance ye- via hole kwisekethe kukwandisa ixesha lokunyuka kwesignali kunye nokunciphisa isantya sesiphaluka. Ixabiso elincinci le-capacitance, isiphumo sincinci.

3. I-Parasitic inductance ye-vias
Indlela yokudlula ngokwayo ine-parasitic inductance. Kuyilo lweesekethe zedijithali ezinesantya esiphezulu, umonakalo obangelwa yi-parasitic inductance ye-via idla ngokuba mkhulu kunempembelelo yesakhono separasitic. I-parasitic series inductance ye-via iya kwenza buthathaka umsebenzi we-bypass capacitor kwaye yenza buthathaka isiphumo sokuhluza yonke inkqubo yamandla. Ukuba u-L ubhekiselele kwi-inductance ye-via, h bubude be-via, kwaye d bububanzi bomngxuma osembindini, inductance yeparasitic ye-via iyafana:

L=5.08h［ln(4h/d) 1］

Inokubonwa kwifomula yokuba ububanzi be-via bunempembelelo encinci kwi-inductance, kwaye ubude bendlela bunempembelelo enkulu kwi-inductance.

4. Ukungaphumeleli ngeteknoloji
Non-ngodlula vias ziquka vias imfama kunye vias wangcwatywa.

Kwi-non-through ngetekhnoloji, ukusetyenziswa kwe-vias eyimfama kunye nokungcwatywa kwe-vias kunokunciphisa kakhulu ubungakanani kunye nomgangatho we-PCB, ukunciphisa inani leeleya, ukuphucula ukuhambelana kombane wombane, ukwandisa iimpawu zeemveliso zombane, ukunciphisa iindleko, kwaye umsebenzi woyilo olulula ngakumbi kwaye ukhawuleza. Kuyilo PCB zemveli kunye nokusetyenzwa, ngokusebenzisa imingxunya unokuzisa iingxaki ezininzi. Okokuqala, bahlala kwindawo enkulu esebenzayo, kwaye okwesibini, inani elikhulu lemingxunya lipakishwe ngokuxineneyo kwindawo enye, nto leyo edala umqobo omkhulu kwi-wiring yangaphakathi ye-PCB ye-multilayer. Ezi kwimingxunya zithatha indawo efunekayo yocingo, kwaye zidlula ngamandla kubonelelo lwamandla kunye nomhlaba. Umphezulu womgca wocingo uya kutshabalalisa iimpawu ze-impedance ze-power ground wire layer kwaye wenze ukuba umaleko wocingo lomhlaba ungasebenzi. Kwaye indlela eqhelekileyo yokugaya i-drilling iya kuba ngamaxesha angama-20 umthwalo womsebenzi ongekho ngobuchwepheshe bomngxuma.

Kuyilo lwePCB, nangona ubukhulu beepads kunye ne-vias ziye zancipha ngokuthe ngcembe, ukuba ubungqingqwa bomaleko webhodi abuncitshiswanga ngokulinganayo, umyinge we-aspect ratio yomngxuma uya kwanda, kwaye ukwanda komyinge womngxuma kuya kunciphisa. ukuthembeka. Ngokuvuthwa kobuchwepheshe be-laser bokomba obuphambili kunye ne-plasma eyomileyo yetekhnoloji ye-etching, kunokwenzeka ukuba kufakwe imingxuma emincinci eyimfama engangeni kunye nemingxuma emincinci engcwatyiweyo. Ukuba ububanzi bezi vias non-okungena yi 0.3mm, parameters parasitic iya kuba Malunga 1/10 umngxuma yesiqhelo yesiqhelo, nto leyo ephucula ukuthembeka PCB.

Ngenxa yokungaphumeleli ngeteknoloji, kukho ii-vias ezimbalwa ezinkulu kwi-PCB, ezinokubonelela ngesithuba esithe kratya sokulandela umkhondo. Indawo eseleyo ingasetyenziselwa iinjongo zokukhusela indawo enkulu ukuphucula ukusebenza kwe-EMI/RFI. Kwangaxeshanye, indawo eseleyo engaphezulu ingasetyenziselwa umaleko wangaphakathi ukukhusela ngokuyinxenye isixhobo kunye neentambo ezingundoqo zenethiwekhi, ukuze zibe nokusebenza kombane. Ukusetyenziswa kwe-vias engadlulanga kwenza kube lula ukukhupha izikhonkwane zesixhobo, ikwenza kube lula ukuhambisa izixhobo zentsimbi ezinoxinano oluphezulu (ezifana nezixhobo ezipakishweyo ze-BGA), ukunciphisa ubude bocingo, kunye nokuhlangabezana neemfuno zexesha leesekethe ezinesantya esiphezulu. .

5. Ngokukhethwa kwi-PCB eqhelekileyo
Kuyilo oluqhelekileyo lwePCB, amandla eparasitic kunye ne-parasitic inductance of the via nefuthe elincinane kuyilo lwePCB. Kuyilo lwe-PCB ye-1-4 yomaleko, 0.36mm/0.61mm/1.02mm (umngxuma ogrunjiweyo/iphedi/AMAMANDLA kwindawo yokwahlula ikhethwa ngokubanzi) ) I-Vias ingcono. Kwimigca yesignali eneemfuno ezizodwa (ezifana nemigca yamandla, imigca yomhlaba, imigca yewotshi, njl.), i-0.41mm / 0.81mm / 1.32mm vias ingasetyenziswa, okanye i-vias yobunye ubungakanani inokukhethwa ngokweyona meko.

6. Ngoyilo kwi-PCB enesantya esiphezulu
Ngokusebenzisa uhlalutyo olungentla lweempawu ze-parasitic ze-vias, siyabona ukuba kuyilo lwe-PCB olunesantya esiphezulu, i-vias ebonakala ilula idla ngokuzisa iziphumo ezibi kakhulu kuyilo lwesekethe. Ukuze kuncitshiswe iziphumo ezibi ezibangelwa yimpembelelo ye-parasitic ye-vias, oku kulandelayo kunokwenziwa kuyilo:

(1) Khetha ingqiqo ngesayizi. Kuyilo lwePCB yoxinaniso olunemigangatho emininzi, kungcono ukusebenzisa i-0.25mm/0.51mm/0.91mm (imingxuma egrunjiweyo/iipadi/indawo yokwahlula AMANDLA) nge-vias; kwezinye PCBs ezinoxinano oluphezulu, 0.20mm/0.46 nayo ingasetyenziswa mm/0.86mm vias, ungazama kwakhona vias non-ngokudlula; kumandla okanye nge-vias yomhlaba, unokuqwalasela ukusebenzisa ubungakanani obukhulu ukunciphisa i-impedance;

(2) Ubukhulu bendawo yokwahlula AMANDLA, kokukhona ingcono, kuthathelwa ingqalelo i- via density kwi-PCB, ngokubanzi D1=D2 0.41;

(3) Zama ukungaguquguquki iileya zeempawu zophawu kwiPCB, nto leyo ethetha ukunciphisa i-vias;

(4) Ukusetyenziswa kwe-PCB ebhityileyo kunceda ekunciphiseni iiparamitha ezimbini zeparasitic zendlela;

(5) Amandla kunye nezikhonkwane zomhlaba kufuneka zenziwe ngemingxuma ekufutshane. Imfutshane isikhokelo phakathi komngxuma kunye nephini, kungcono, kuba ziya kwandisa i-inductance. Kwangaxeshanye, amandla kunye nezikhokelo zomhlaba kufuneka zibe ngqindilili ngangokunokwenzeka ukunciphisa impedance;

(6) Beka ezinye ii-vias zokumisa kufuphi ne-vias yomgca wesignali ukubonelela umgama omfutshane welophu yomqondiso.

Kakade ke, imiba ethile kufuneka ihlalutywe ngokweenkcukacha xa uyilwa. Ukuqwalasela zombini ixabiso kunye nomgangatho wesignali ngokubanzi, kuyilo lwePCB olunesantya esiphezulu, abaqulunqi bahlala benethemba lokuba umngxuma omncinci udlula umngxuma, ungcono, ukuze kushiywe indawo yocingo ebhodini. Ukongeza, incinci i- via hole, eyakhe Incinci i-parasitic capacitance, ifaneleke ngakumbi kwiisekethe zesantya esiphezulu. Kuyilo PCB olunoxinano oluphezulu, ukusetyenziswa kwe-non-through vias kunye nokunciphisa ubungakanani be-vias kwakhona kuzise ukonyuka kweendleko, kunye nobungakanani be-vias abunakuncitshiswa ngokungenasiphelo. Ichatshazelwa yinkqubo yokomba kunye ne-electroplating yabavelisi be-PCB. Izithintelo zobuchwephesha kufuneka zinikwe ingqwalasela elungeleleneyo kuyilo lwePCB ezinesantya esiphezulu.