In HDI PCB yothamanga kwambiri kupanga, kudzera pakupanga ndi chinthu chofunikira. Imakhala ndi dzenje, malo ozungulira dzenje, ndi malo odzipatula a POWER wosanjikiza, omwe nthawi zambiri amagawidwa m’mitundu itatu: mabowo akhungu, mabowo okwiriridwa komanso mabowo. Mu ndondomeko PCB kamangidwe, mwa kusanthula kwa parasitic capacitance ndi parasitic inductance wa vias, ena kusamala mu kamangidwe ka mkulu-liwiro PCB vias ndi mwachidule.

At present, high-speed PCB design is widely used in communications, computers, graphics and image processing and other fields. All high-tech value-added electronic product designs are pursuing features such as low power consumption, low electromagnetic radiation, high reliability, miniaturization, and light weight. In order to achieve the above goals, via design is an important factor in high-speed PCB design.

1. Kudzera
Kudzera ndi chinthu chofunikira pakupanga kwamitundu yambiri ya PCB. A via makamaka wapangidwa ndi magawo atatu, limodzi ndi dzenje; chinacho ndi malo a pad kuzungulira dzenje; ndipo chachitatu ndi malo odzipatula a POWER layer. Njira yopangira dzenje ndikuyika chitsulo pamwamba pa cylindrical pakhoma la dzenje la dzenje pogwiritsa ntchito mankhwala kuti agwirizane ndi zojambulazo zamkuwa zomwe zimayenera kulumikizidwa ndi zigawo zapakati, ndi kumtunda ndi kumunsi kwa mbali. kudzera pa dzenje amapangidwa kukhala mapepala wamba Maonekedwewo amatha kulumikizidwa mwachindunji ndi mizere kumtunda ndi kumunsi, kapena osalumikizidwa. Vias amatha kugwira ntchito yolumikizira magetsi, kukonza kapena kuyika zida.

Ma Vias nthawi zambiri amagawidwa m’magulu atatu: mabowo akhungu, maenje okwiriridwa komanso mabowo.

Mabowo akhungu ali pamwamba ndi pansi pa bolodi losindikizidwa ndipo ali ndi kuya kwina. Amagwiritsidwa ntchito kugwirizanitsa mzere wa pamwamba ndi mzere wamkati wamkati. Kuzama kwa dzenje ndi m’mimba mwake wa dzenje nthawi zambiri sizidutsa chiŵerengero china.

M’kwiriridwa dzenje amatanthauza dzenje kugwirizana ili mu wosanjikiza wamkati wa bolodi kusindikizidwa dera, amene sapitirira pamwamba pa bolodi dera.

Akhungu vias ndi vias m’manda onse zili mkati wosanjikiza wa bolodi dera, amene anamaliza ndi kudzera-dzenje kupanga ndondomeko pamaso lamination, ndi zigawo zingapo zamkati akhoza anadutsana pa mapangidwe vias.

Kudzera mabowo, amene kudutsa lonse dera bolodi, angagwiritsidwe ntchito interconnection mkati kapena chigawo chimodzi unsembe malo dzenje. Popeza kudzera mabowo n’zosavuta kukhazikitsa mu ndondomeko ndi mtengo wotsika, zambiri kusindikizidwa dera matabwa ntchito kudzera mabowo.

2. Parasitic capacitance ya vias
The via palokha ali parasitic capacitance pansi. Ngati m’mimba mwake wa dzenje lodzipatula lomwe lili pansi pa bwalo ndi D2, m’mimba mwake mwa pad ndi D1, makulidwe a PCB ndi T, ndipo gawo la dielectric la gawo lapansi ndi ε, ndiye The parasitic capacitance of kudzera ikufanana ndi:

C =1.41εTD1/(D2-D1)

Chotsatira chachikulu cha parasitic capacitance ya kudzera pa dzenje pamtunda ndikukulitsa nthawi yowuka ya chizindikiro ndikuchepetsa liwiro la dera. Zing’onozing’ono capacitance mtengo, ndi zochepa zotsatira.

3. Parasitic inductance of vias
The via palokha ili ndi parasitic inductance. Pamapangidwe a mabwalo othamanga kwambiri a digito, kuvulaza komwe kumachitika chifukwa cha parasitic inductance ya via nthawi zambiri kumakhala kokulirapo kuposa mphamvu ya parasitic capacitance. The parasitic series inductance of the via idzafooketsa ntchito ya bypass capacitor ndikufooketsa kusefa kwa dongosolo lonse lamphamvu. Ngati L amatanthauza kulowetsa kwa via, h ndiye kutalika kwa via, ndipo d ndi mainchesi a dzenje lapakati, kulowetsa kwa parasitic kwa via kumafanana ndi:

L=5.08h［ln(4h/d) 1］

It can be seen from the formula that the diameter of the via has a small influence on the inductance, and the length of the via has the greatest influence on the inductance.

4. Osadutsa kudzera muukadaulo
Non-through vias include blind vias and buried vias.

Mu osakhala kudzera mwaukadaulo, kugwiritsa ntchito ma vias akhungu ndi ma vias okwiriridwa kungachepetse kwambiri kukula ndi mtundu wa PCB, kuchepetsa kuchuluka kwa zigawo, kuwongolera maginito amagetsi, kukulitsa mawonekedwe azinthu zamagetsi, kuchepetsa ndalama, komanso kupanga kapangidwe ka ntchito zambiri Zosavuta komanso zachangu. Mu chikhalidwe PCB kamangidwe ndi processing, kudzera mabowo angabweretse mavuto ambiri. Choyamba, amakhala ndi malo ambiri ogwira ntchito, ndipo kachiwiri, ambiri mwa mabowo amadzaza malo amodzi, zomwe zimapanganso chopinga chachikulu cha mawaya amkati a multilayer PCB. Izi kudzera m’mabowo zimatenga malo ofunikira pa mawaya, ndipo zimadutsa mozama pamagetsi ndi pansi. Pamwamba pa waya wosanjikiza adzawononganso impedance makhalidwe a mphamvu pansi waya wosanjikiza ndi kupanga mphamvu pansi waya wosanjikiza ntchito. Ndipo ochiritsira mawotchi njira kubowola adzakhala 20 nthawi XNUMX ntchito sanali kudzera mdzenje luso.

Mu PCB kapangidwe, ngakhale kukula kwa ziyangoyango ndi vias pang’onopang’ono utachepa, ngati makulidwe a bolodi wosanjikiza si proportionally yafupika, ndi mbali chiŵerengero cha kudzera dzenje adzawonjezeka, ndi kuwonjezeka kwa chiŵerengero cha kupyola dzenje kuchepetsa. kudalirika. Ndi kukhwima kwaukadaulo wapamwamba pobowola laser ndi plasma youma etching luso, n’zotheka kugwiritsa ntchito osalowerera mabowo ang’onoang’ono akhungu ndi mabowo ang’onoang’ono okwiriridwa. Ngati m’mimba mwake mwa vias amenewa sanali ozama ndi 0.3mm, magawo parasitic adzakhala About 1/10 wa dzenje choyambirira ochiritsira, amene bwino kudalirika kwa PCB.

Chifukwa chosadutsa kudzera muukadaulo, pali ma vias ochepa pa PCB, omwe atha kupereka malo ochulukirapo. Malo otsalawo atha kugwiritsidwa ntchito pazifukwa zazikulu zotchinjiriza kuwongolera magwiridwe antchito a EMI/RFI. Panthawi imodzimodziyo, malo otsalawo angagwiritsidwe ntchito kuti gawo lamkati liteteze pang’ono chipangizo ndi zingwe zazikulu za intaneti, kuti zikhale ndi magetsi abwino kwambiri. Kugwiritsa ntchito ma vias osadutsa kumapangitsa kukhala kosavuta kutulutsa zikhomo za chipangizocho, kupangitsa kuti zikhale zosavuta kuyendetsa zida zapini zolimba kwambiri (monga zida zopakidwa za BGA), kufupikitsa kutalika kwa mawaya, ndikukwaniritsa zofunikira zanthawi ya mabwalo othamanga kwambiri. .

5. Kudzera kusankha mu PCB wamba
M’mapangidwe wamba a PCB, mphamvu ya parasitic ndi inductance ya parasitic ya kudzera imakhala ndi zotsatira zochepa pamapangidwe a PCB. Kwa mapangidwe a 1-4 wosanjikiza PCB, 0.36mm/0.61mm/1.02mm (bowo lobowoleredwa/pad/MPOWER kudzipatula nthawi zambiri amasankhidwa) ) Vias ndi bwino. Pakuti mizere chizindikiro ndi zofunika zapadera (monga mizere mphamvu, mizere pansi, mizere wotchi, etc.), 0.41mm/0.81mm/1.32mm vias angagwiritsidwe ntchito, kapena vias makulidwe ena akhoza kusankhidwa malinga ndi mmene zinthu zilili.

6. Kudzera kapangidwe mu mkulu-liwiro PCB
Kupyolera mu kusanthula pamwamba pa makhalidwe parasitic wa vias, tingaone kuti mkulu-liwiro PCB kamangidwe, Vis zooneka zosavuta nthawi zambiri kubweretsa zotsatira zoipa kwambiri kwa kamangidwe dera. Pofuna kuchepetsa mavuto chifukwa cha parasitic zotsatira za vias, zotsatirazi zikhoza kuchitika mu kapangidwe:

(1) Sankhani wololera ndi kukula. Pakuti Mipikisano wosanjikiza ambiri-kachulukidwe PCB kamangidwe, ndi bwino ntchito 0.25mm/0.51mm/0.91mm (bowobowo / ziyangoyango / MPHAMVU kudzipatula dera) vias; kwa ma PCB olimba kwambiri, 0.20mm/0.46 angagwiritsidwenso ntchito mm/0.86mm vias, mutha kuyesanso osati kudzera panjira; kwa mphamvu kapena pansi vias, mungaganizire ntchito yaikulu kukula kuchepetsa impedance;

(2) Malo odzipatula a MPHAMVU akakulirakulira, ndibwino, poganizira kuchuluka kwa PCB, nthawi zambiri D1=D2 0.41;

(3) Yesetsani kusintha zigawo za zizindikiro chizindikiro pa PCB, kutanthauza kuchepetsa vias;

(4) Kugwiritsa ntchito PCB yocheperako kumathandizira kuchepetsa magawo awiri a parasitic panjira;

(5) Mphamvu ndi zikhomo pansi ziyenera kupangidwa kudzera mabowo pafupi. Kufupikitsa kutsogolo pakati pa dzenje ndi pini, ndibwino, chifukwa zidzawonjezera inductance. Panthawi imodzimodziyo, mphamvu ndi zotsogolera pansi ziyenera kukhala zonenepa kwambiri kuti zichepetse kusokoneza;

(6) Ikani ena vias grounding pafupi vias wa wosanjikiza chizindikiro kupereka lalifupi mtunda kuzungulira kwa chizindikiro.

Zoonadi, nkhani zachindunji ziyenera kufufuzidwa mwatsatanetsatane popanga. Poganizira za mtengo ndi mtundu wa ma siginecha momveka bwino, pamapangidwe othamanga kwambiri a PCB, opanga nthawi zonse amayembekeza kuti kabowo kakang’ono ndi kabwinoko, kotero kuti mawaya ambiri azisiyidwa pa bolodi. Kuphatikiza apo, ang’onoang’ono ang’onoang’ono kudzera pa dzenje, ake Ochepa a parasitic capacitance, omwe ali oyenera kwambiri mabwalo othamanga kwambiri. Mu kachulukidwe PCB kamangidwe, ntchito sanali kudzera vias ndi kuchepetsa kukula kwa vias wabweretsanso za kuwonjezeka mtengo, ndi kukula kwa vias sangathe kuchepetsedwa mpaka kalekale. Zimakhudzidwa ndi kubowola kwa opanga PCB ndi ma electroplating. Zoperewera zaukadaulo ziyenera kuganiziridwa moyenera pamapangidwe a PCB othamanga kwambiri.