Umhlahlandlela Wokuklama we-PCB Wezingqimba Ezingama-28: I-Stackup, Izinto Zokusebenza kanye Nobuqotho Besignali ye-28Gbps

Idizayini ye-PCB enezingqimba ezingu-28 itholakala ekuxhumaneni kobuningi bomzila kanye nobunzima bokukhiqiza bangempela. Ikhethwa lapho izingqimba ezingu-24 zingakwazi ukudonsa inani lezingqimba zesiginali elidingwa uhlelo oluyinkimbinkimbi, lapho ukulethwa kwamandla kudinga izindiza ezizinikele kakhulu kunalokho okunikezwa yinani lezingqimba eziphansi, noma lapho ubukhulu bezingxenye zeprosesa ye-AI, i-network switch ASIC, noma i-FPGA ethuthukisiwe idinga ibhodi elingahambisa yonke isiginali nge-impedance elawulwayo. Lo mhlahlandlela ubhalelwe onjiniyela bokuklama kanye nabaphathi bokuthenga abasebenza ezinhlelweni zangempela zezingqimba ezingu-28 - uhlanganisa izinqumo ezinquma ukuthi umenzi we-PCB onezingqimba ezingu-28 angakha yini ngempela idizayini yakho ngokwezidingo.

1. Kunini lapho izendlalelo ezingu-28 ziba yisibalo esifanele sezendlalelo?

1.1 Izidingo Zokujiya Komzila Eziqhuba Izinqumo Ezinezingqimba Ezingu-28

Isinqumo sokusebenzisa izendlalelo ezingu-28 asivamile ukwenziwa ngokungahleliwe. Ngokuvamile silandela ukuhlaziywa kokubalwa kwezingqimba okuhleliwe: isilinganiso sobuningi bomzila (ubude obuphelele obuhlukaniswe ngendawo yomzila etholakalayo ngesendlalelo ngasinye) esibonisa ukuthi izendlalelo ezingu-24 azikwazi ukwamukela inani lesignali ebubanzini bokulandelela obudingekayo kanye nesikhala. Izimbangela ezivamile:

• Amaphakheji e-BGA angaphezu kwamaphini angu-2,500 anephimbo elingu-0.8 mm noma elingu-1.0 mm, lapho umzila wokuphunyuka udinga izendlalelo eziningi zesignali ohlangothini ngalunye lwephakheji
• Amaphakheji e-multi-chip (ukulungiswa kwe-MCM noma i-2.5D interposer) lapho inani le-I/O elihlanganisiwe lidlula umthamo wokuhambisa ongama-layer angu-24
• Izixhumanisi ze-serial zesivinini esiphezulu zibalwa ngaphezu kwama-differential pairs angu-64 ku-28 Gbps+, lapho i-pair ngayinye kumele iqondiswe ngezindiza zokubhekisela ngaphezulu nangaphansi kulo lonke ubude bayo obuphelele.
• Izizinda zamandla ezidlula ubunzima obungu-6-8, ezidinga izindiza ezizinikele zama-voltage rails amaningi ukuze kugwenywe ukuhlanganiswa komsindo wendiza ehlanganyelwe

Uma umklamo wakho ungahlangabezani okungenani ezimbili zalezi zindlela, ukubuyekezwa okuhlelekile kwezindlela ezingasetshenziswa ngezingqimba ezingu-24 kufanelekile ukukuqeda ngaphambi kokuzibophezela ezindleleni zokusebenzisa amathuluzi nezingqimba ezingu-28.

1.2 Inzuzo Yezingqimba Ezingama-28 Ngaphezu Kwezingqimba Ezingama-24 Nezingama-32

A 28-layer stackup provides four more layers than a 24-layer construction, but the useful routing and plane allocation depends on the design. Lamination cycles, cost and yield cannot be inferred from layer count alone: via structure, material system, board dimensions, copper distribution and acceptance requirements also determine the fabrication route. Review the PCB fabrication workflow against the proposed construction before issuing an RFQ.

2. Ukuhlela Okuhlanganisiwe Kwemiklamo Esheshayo Enezingqimba Ezingu-28

2.1 Izimiso Zokwabiwa Kwezingqimba

I-stackup enezingqimba ezingu-28 ehlelwe kahle ilandela izimiso zobuqotho besignali eziba zibaluleke kakhulu, hhayi kancane, njengoba inani lezingqimba landa:

• Ingqimba ngayinye yesignali yesivinini esikhulu kumele ibe nendiza yokubhekisela eqhubekayo eduze kwayo. Ezingqimbeni ezingu-28, akukho ukushoda kwezingqimba zendiza — zisebenzise ukudala izindawo zomugqa we-strip kuzo zonke izingqimba ezibalulekile. Umzila we-microstrip ezingqimbeni zangaphandle kufanele ugcinelwe izingqimba lapho isidingo sokulawulwa kwe-impedance singesesibili.
• Gcina ukulingana phakathi kwebhodi. I-stackup engalingani — isisindo sethusi esihlukene, ubukhulu obuhlukene be-dielectric, noma izinombolo ezahlukene zezendlalelo zesiginali kanye nezindiza ohlangothini ngalunye lwesikhungo — idala umzuzu wokugoba wenetha ebhodini ngesikhathi se-lamination kanye nokujikeleza kokushisa. Ezingqimbeni ezingu-28 kanye nobukhulu obuqediwe obungu-3.0–3.6 mm, i-warpage evela kuma-stackup angalingani kunzima ukuyilungisa futhi ingabangela ukwehluleka kokuhlanganiswa. I-IPC Class 3 idinga ukugoba nokusonta ≤0.5%.
• Hlanganisa izindiza zamandla ngokwesizinda se-voltage, kube nezingqimba zesiginali phakathi kwazo lapho kungenzeka khona. Ipheya elihamba phambili (amandla + umhlabathi) phakathi kwezingqimba ezimbili zesignali lisebenza njenge-capacitor yokuhlukanisa ene-inductance emfushane kakhulu yeluphu - inzuzo yangempela ye-PDN. Yakha i-stackup ukuze le geometry isetshenziswe ezizindeni zamandla ezinomsindo kakhulu.

Ukuze uthole umzila we-BGA ohamba kahle kakhulu ohamba ngezingqimba ezingu-28, i-HDI ngezakhiwo — ama-microvia ahlanganisiwe kanye ne-via-in-pad — ivame ukudingeka. Lokhu kudinga umenzi onomugqa we-lamination olandelanayo osebenzayo kanye nekhono lokubhoboza nge-laser elizinikele, hhayi nje ikhono lokucaphuna inani lezingqimba.

2.2 Ama-Dielectric Thickness and Impedance Targets

Ezingqimbeni ezingu-28, ubukhulu be-dielectric phakathi kwezingqimba zesignali kanye nezindiza zazo zokubhekisela ngokuvamile busebangeni elingu-75-150 µm lezendlalelo zangaphakathi ze-stripline. Lokhu kushayela ububanzi be-trace — i-trace engu-50 Ω eyodwa ephethe i-dielectric engu-100 µm ene-Er = 3.7 (Isola 370HR) cishe ububanzi obungu-170-180 µm, okungalawuleka ekukhiqizweni kwe-PCB yesimanje elawulwa yi-impedance . Kuma-differential pairs angu-100 Ω angu-differential, ububanzi be-trace kanye nenhlanganisela yesikhala kumele kuboniswe yi-field solver yomenzi esebenzisa i-real stackup geometry — hhayi cishe kusuka kubabala abaku-inthanethi.

Ama-dielectric amancane (75 µm noma ngaphansi) avumela ukuhlangana okuqinile phakathi kwama-differential pairs kanye ne-parasitic capacitance ephansi kuma-node anesivinini esikhulu, kodwa adinga umenzi onekhono elibonisiwe lokubamba ukubekezelelana kobukhulu be-dielectric (±10% we-nominal ngemuva kwe-lamination imfuneko ye-IPC Class 3). Ku-75 µm nominal, ±10% isho ±7.5 µm — ukubekezelelana okudinga umenzi ukuthi achaze ukugeleza kwe-prepreg resin ngokunembile kwenhlanganisela ngayinye yezinto kanye neresiphi ye-lamination.

3. Ubuqotho Besignali ku-28 Gbps nangaphezulu

3.1 Isabelomali Sokulahlekelwa Kokufakwa Kwamabhodi Anezingqimba Ezingama-28

Ukufeza ukusebenza kwesignali yemvamisa ephezulu okudingwa yizixhumanisi ze-serdes ezingama-28 Gbps+ kudinga ukukhethwa ngokucophelela kwezinto kanye nokucaciswa kwe-copper foil ngaphambi kokuba i-stackup iqandiswe. Isignali ye-NRZ engama-28 Gbps (eyisisekelo esingu-14 GHz) ewela ibhodi elingu-300 mm kungqimba lwangaphakathi lwe-stripline ihlangabezana nokulahlekelwa yi-conductor, ukulahlekelwa yi-dielectric, kanye nokulahlekelwa yi-via. Ebhodini elijwayelekile elinezingqimba ezingama-28 elisebenzisa i-Isola 370HR enethusi elijwayelekile:

• Ukulahlekelwa yi-conductor (ithusi elijwayelekile le-ED): cishe 0.18–0.22 dB/cm ku-14 GHz
• Ukulahleka kwe-dielectric (Df = 0.021 ku-10 GHz): cishe 0.12–0.15 dB/cm ku-14 GHz
• Ukulahleka kwesiteshi okuhlanganisiwe kwama-300 mm: 9–11 dB, ngaphambi kokusebenzisa iminikelo

Lesi sabelomali sincane kakhulu kune-28 Gbps NRZ ngaphandle kokulinganisa. Kumadizayini adinga ukulahlekelwa okuphansi — noma ukusayina kwe-PAM4 ku-56 Gbps (28 Gbaud) lapho isabelomali sokulahlekelwa sincane khona — i-Panasonic Megtron 6 (Df = 0.002) enethusi le-VLP inciphisa ukulahlekelwa okuhlangene kube cishe yi-5–6 dB ngobude besiteshi esifanayo, okunikeza umkhawulo omkhulu wokulinganisa kanye nokuthembeka kwesistimu.

Umphumela ongokoqobo: ukukhetha izinto zokwakha umklamo onezingqimba ezingu-28 ku-28 Gbps+ akusona isinqumo sesibili. Kufanele kwenziwe kusenesikhathi enkambisweni yokuklama, kuqhutshwa isabelomali sokulahlekelwa kwesiteshi esilinganisiwe kusukela ekulingiseni kwangaphambi kokuhlelwa, futhi kukhiywe ngaphambi kokuba umenzi akhethwe — ngoba akubona bonke abakhiqizi abanezingqimba ezingu-28 abagcina noma abacubungula njalo i-Megtron 6.

3.2 Ngokusebenzisa i-Discontinuity kanye ne-Back-Drilling ezingqimbeni ezingu-28

I-through-via ebhodini elinezingqimba ezingu-28 elisetshenziselwa ingxenye encane yobukhulu bebhodi ishiya i-stub ezwakala ngaphakathi komkhawulokudonsa wesignali. Ebhodini elinezingqimba ezingu-28 elinobukhulu obuqediwe obungu-3.2 mm lapho i-via ixhuma khona kuphela izingqimba ezi-1–14, i-stub engasetshenziswanga cishe ingu-1.6 mm — izwakala cishe ku-30 ​​GHz. Emasignalini angu-28 Gbps e-NRZ anamandla ku-14 GHz, lokhu kuzwakala kusemngceleni we-harmonic; kumasignali angu-56 Gbps, ingaphakathi kwebhendi ngqo.

Ukubhoboza ngemuva kususa okungasetshenziswanga nge-stub, kushiye insalela elawulwayo ngokuvamile engu-≤0.25 mm. Le nqubo idinga ukubhoboza ngomshini olawulwa ngokujula okunokunemba kwe-Z-axis engu-±50–75 µm kanye nemodeli yesinxephezelo enobukhulu obulinganisiwe kubhodi ngalinye. Cela izithombe zesigaba esiphambene zama-vias abhobozekile ngemuva kusukela ekukhiqizweni kwakamuva komkhiqizi — ubude bensalela ye-stub elinganisiwe bubonakala ngqo esigabeni futhi buyisiqinisekiso esithembeke kakhulu sekhono labo lenqubo yokubhoboza emuva.

4. Ukwakhiwa Kwenethiwekhi Yokulethwa Kwamandla Kumabhodi Anezingqimba Ezingu-28

4.1 Ukubalwa Kwendiza Nokuhlukaniswa Kwesizinda Samandla

Umklamo onezingqimba ezingu-28 uvame ukwabela izendlalelo ezingu-10-14 ezindizeni (amandla nomhlabathi kuhlangene) kanye nezendlalelo ezingu-14-18 ukuze kuqondiswe isignali. Lokhu kuxinana kwendiza kwenza kube nokuhlukaniswa kwesizinda samandla sangempela: izindiza ezihlukene ezizinikele ze-core voltage, i-I/O voltage, ukuphakelwa kwe-analog, i-DDR termination voltage, kanye ne-assistant rails — ngayinye inendlela yayo yokubuya kanye nesu lokuhlukanisa. Okunye — izindiza ezabiwe ezine-split coupling pours — zethula ukuhlanganiswa kwemvamisa ephezulu phakathi kwezizinda zamandla okunzima ukuzimodela futhi okunzima ukuzisusa kusakhiwo esikhona.

Kumabhodi esikhungo sedatha se-AI kanye namapulatifomu okuxhumana aphezulu lapho amashumi ama-ampere ku-sub-1V core voltage kumele alethwe nge-millivolt-level ripple, umklamo we-PDN uklanywe ngokubambisana ne-stackup. Ama-plane pair akhethelwe i-core voltage kumele akhonjwe ngaphambi kokuba kuqale ukubekwa, angabelwa kunoma yiziphi izendlalelo ezisele ngemva kokuthi umzila wesignali usuqediwe.

4.2 Ukuhlukanisa Ukubekwa Kwe-Capacitor kanye Nemiphumela Ye-Via Stub

Ama-capacitor okususa abekwe ebusweni bebhodi kumele axhumane nezindiza zamandla kanye nomhlabathi ngokusebenzisa izakhiwo. I-Via ngayinye yethula i-inductance — cishe i-0.5–1.0 nH yebhodi elijwayelekile elidlula nge-3.2 mm. Ezingqimbeni ezingu-28 lapho izindiza zamandla zingase zibe zijule khona ku-stackup, i-inductance esuka ku-capacitor yokususa efakwe ebusweni iye ku-power plane efanele ingaba yinto ebalulekile ngokwanele ukunciphisa ukusebenza kwe-capacitor ngaphezu kwe-100–200 MHz. Ukunciphisa lokhu nge-inductance kudinga ukusebenzisa ama-array (ama-via amaningi ahambisanayo) nokubeka ama-capacitor okususa ku-layer eseduze nengxenye ayisebenzelayo — okuvame ukusho ukuwafaka ku-stackup esigabeni esiphakathi se-lamination.

5. Ukuhumusha Izidingo ze-SI zibe yizincazelo zokukhiqiza

5.1 Izici Ezicacisiwe Okumele Zibe Zicacile

I -oda le-PCB elinezingqimba ezingu-28 elichaza idatha ye-Gerber kuphela kanye nokubalwa kwezingqimba akuyona incazelo yokwenziwa. Izinto ezilandelayo kumele zishiwo ngokucacile ngokubhala:

• Izinto ezilaminate ngomkhiqizi, ibanga, kanye nencazelo yeshidi lokuskena le-IPC-4101 (isb., “Isola 370HR, /126”)
• Uhlobo lwefoyili yethusi kanye nesisindo ngokwesendlalelo noma iqembu lesendlalelo (isb., “ithusi le-VLP, 0.5 oz ezingqimbeni zesignali zangaphakathi L3–L26”)
• Ama-impedance alawulwayo aneklasi ye-net, isabelo sezendlalelo, kanye nokubekezelelana (isb., “umehluko we-100 Ω, i-L5/L6 pair, ±5%”)
• Izidingo zokubhoboza ngemuva: okuhamba ngamaqembu, isiqondiso sokubhoboza, ubude obukhulu besigxobo
• Ikilasi le-IPC: ngokusobala “IPC-6012 Ikilasi 3” — ungashiyi lokhu kungashiwongo
• Ukuphela kobuso okunencazelo yobukhulu (isb., “ENIG, 2 µin Au minimum / 150 µin Ni”)
• Izidingo zokuhlola: I-100% flying probe noma i-fixture kagesi test, i-TDR impedance coupon test per panel

5.2 Ukubuyekezwa kwe-DFM njengomcimbi Wokufaneleka Kwabahlinzeki

Cela ukubuyekezwa kwe-DFM komkhiqizi ngaphambi kokuvuma ukukhiqizwa. Umkhiqizi onekhono onezingqimba ezingu-28 uzoveza izinkinga zangempela: ukwephulwa kwendandatho ye-annular kuma-vias anesilinganiso esiphezulu, izingxabano zokususa i-back-drill, izinkinga zebhalansi yethusi ezibikezela i-warpage, noma izinkinga zokukhetha kusengaphambili kuma-targets amancane e-dielectric. Umkhiqizi obuyisela ukubuyekezwa kwe-DFM ngaphandle kokuphawula ngomklamo oyinkimbinkimbi onezingqimba ezingu-28 akakabukezi amafayela noma akanabo onjiniyela abakwazi ukuwabuyekeza. Yomibili imiphumela kufanele ikhiphe umhlinzeki.

6. Ukuhlola Umhlinzeki we-PCB onezingqimba ezingu-28: Ubufakazi Obubalulekile

6.1 I-Matrix Yobufakazi Bomhlinzeki

6.2 Izimpawu Ezibomvu Ngesikhathi Sokuhlolwa Kwabahlinzeki

• Umhlinzeki akakwazi ukukhiqiza izithombe zesigaba esiphambene kusukela ekukhiqizweni kwezingqimba ezingu-28 ezinsukwini ezingu-90 ezedlule - kusho ukuthi i-28L ayikhiqizi esebenzayo kubo
• I-Impedance Idatha ye-Cpk ayitholakali noma ikhombisa i-Cpk <1.33 — ikhombisa ukulawulwa kwenqubo okunganele kokubekezelelana kwe-±5%
• Umhlinzeki akasebenzisi i-field solver (i-Polar SI, i-iCD, noma okulinganayo) ekubalweni kwe-impedance - kusho ukuthi ububanzi bomkhondo buyalinganiswa, abulinganiswanga
• Ukubuyekezwa kwe-DFM kungaphansi kwamahora ama-4 komklamo oyinkimbinkimbi onezingqimba ezingama-28 - kubonisa ukuthi amafayela awazange abuyekezwe ngunjiniyela
• Umhlinzeki akakwazi ukusho igama lekhemistri yeplating esetshenziselwa ama-vias anesilinganiso esiphezulu - kubonisa ukungajwayeleki ngezidingo zeplating zeSigaba 3

Xoxa Ngephrojekthi Yakho Ye-PCB Enezingqimba Ezingu-28

7. Isikhathi Sokuhola, Abashayeli Bezindleko, kanye Nokuguqulwa Kwesibonelo Sokukhiqiza

7.1 Isikhathi Sokuhola Esingokoqobo Sezimo Zokwenziwa Ze-PCB Ezinezingqimba Ezingama-28

The lead time for a 28-layer I-PCB prototype depends on material availability, the approved stackup and via structure, drilling and plating requirements, inspection scope and the fabricator’s production schedule. Ask the supplier to confirm the planned lamination sequence, test requirements and delivery milestone after DFM review. A layer count alone is insufficient to validate or reject a proposed delivery time.

Kumabhodi amaningi okukhiqiza angu-50-500, izikhathi zokuhola zezinsuku zebhizinisi ezingu-20-30 zivamile kubahlinzeki abafanelekayo, kanti ukutholakala kwezinto kuyizinto ezivame kakhulu. Umhlinzeki ogcina i-Isola 370HR kanye ne-Megtron 6 ngobukhulu obujwayelekile angaqala ukukhiqiza ngosuku i-DFM evunyiwe ngalo; umhlinzeki o-oda izinto ngomsebenzi ngamunye unezela isonto eli-1-3 ku-oda ngalinye.

7.2 Isakhiwo Sezindleko ze-PCB Enezingqimba Ezingama-28

Izindleko eziyinhloko ezibangela i-PCB enezingqimba ezingu-28, ngokulandelana komthelela:

• Izindleko zezinto: 30–40% wezindleko zebhodi eziphelele. I-Megtron 6 ibiza ngaphezu kuka-4–6× kune-Isola 370HR ngendawo ngayinye. Lo mehluko wezindleko kumele uqinisekiswe ngokuhlaziywa kwe-SI, hhayi ngokuzenzakalelayo ngokucabangela ukuthi "izinto ezingcono zingcono."
• Umsebenzi wokubopha olandelanayo kanye nesikhathi sokucindezela: Umjikelezo ngamunye we-lamination wengeza izindleko eziqondile futhi wandisa isikhathi sokuhola. Imiklamo engakhiwa ngemijikelezo emi-2 esikhundleni semi-3 ishibhile kakhulu — izinqumo zokwakha i-stackup ezenziwe ekuqaleni komklamo zithinta kakhulu izindleko.
• Ukubhoboza emuva: Ingeza izindleko ngeqembu ngalinye elidinga ukubhoboza, kanye nesikhathi sokujikeleza esengeziwe. Ukubhoboza emuva kufanele kusetshenziswe ngokukhetha — kuphela emaqenjini lapho i-stub resonance iwela ngaphakathi komkhawulokudonsa wesignali, hhayi kuwo wonke ama-through-via.
• Ekupheleni kwendawo: I-ENIG ingeza izindleko ezincane uma kuqhathaniswa nenani lebhodi elinezingqimba ezingu-28. I-ENEPIG yezicelo ze-wire bond noma izidingo zeminwe yegolide ingeza okwengeziwe. Cacisa okudingekayo, kodwa ungavele ufinyelele ekuqedeni okubiza kakhulu ngaphandle kwesizathu sohlelo lokusebenza.

7.3 Ukuphatha Ushintsho Lwesibonelo-kuya-Ekukhiqizeni

Igebe phakathi kweprotokholi ephumelelayo nokukhiqizwa okuphindaphindwayo yilapho izinhlelo eziningi ezinezingqimba ezingu-28 zibhekana nezinkinga khona. Iprotokholi yakhiwe ngokunaka okwengeziwe kobunjiniyela; indawo yokukhiqiza isebenza kwimodi ye-batch ngokugeleza kwenqubo ejwayelekile. Ukuvikela ikhwalithi yokukhiqiza:

• Cela idatha ye-impedance Cpk kusuka ku-lot yangaphambi kokukhiqiza — hhayi nje kusuka ku-prototype
• Misa isivumelwano sokukhiya inqubo esichaza umthombo we-laminate ovunyiwe, amapharamitha okufaka i-plating, kanye nephrofayili ye-lamination ngaphambi kokuqala kokukhiqiza
• Cacisa Ukuhlolwa kukagesi okungu-100%. — i-flying probe noma i-fixture — njengemfuneko yesivumelwano kuncazelo yokuthenga, hhayi isicelo esishiywe ekukhetheni komkhiqizi
• Qondanisa Umhlangano we-PCB izidingo zokubekezelela ukwenziwa kusenesikhathi: ukukhetha ukuqeda ubuso, ngokuchazwa kokugcwalisa, kanye nokuba yisicaba kwebhodi kuthinta ngqo isivuno se-SMT esingezansi, futhi lezi zinhlaka kufanele ziqinisekiswe phakathi kwamaqembu okukhiqiza nawokuhlanganisa ngaphambi kokuba kukhishwe indawo yokuqala yokukhiqiza.
• Chaza izinqubo zokulungisa esivumelwaneni sekhwalithi ngaphambi kwesigaba sokuqala sokukhiqiza — hhayi ngemva kokwehluleka kokuqala