Gwaro rekugadzira PCB reLayer 28: Stackup, Zvishandiso & 28Gbps Signal Integrity

Dhizaini yePCB ine 28-layer iri pamharadzano yehuwandu hwepamusoro hwerouting density uye kuoma kwekugadzira chaiko. Inosarudzwa kana 24 layers isingakwanise kutora huwandu hwesignal layer hunodiwa nesystem yakaoma, apo simba rinopa simba rinoda mapuraneti akazvipira kupfuura huwandu hwe layer yakaderera, kana kana component density yeAI processor, network switch ASIC, kana advanced FPGA ichida bhodhi rinogona kuendesa chiratidzo chega chega pa controlled impedance. Gwaro iri rakanyorerwa mainjiniya ekugadzira uye maprocurement manager vanoshanda pamapurogiramu chaiwo e28-layer - rinofukidza sarudzo dzinosarudza kana mugadziri wePCB ane 28 layer anogona chaizvo kuvaka dhizaini yako zvichienderana nezvakatsanangurwa.

1. Makumi maviri nemasere ndiwo akakodzera here kuverenga ma layer?

1.1 Zvinodiwa paKuwedzera Huremu hweRouting Zvinotungamira Sarudzo dzeMaturikirwo makumi maviri nemasere

Sarudzo yekushandisa zvidimbu makumi maviri nemasere haiwanzoitwa nemazvo. Inowanzo tevera ongororo yehuwandu hwezvidimbu: kufungidzira kwehuwandu hwenzira (hurefu hwese hwakakamurwa nenzvimbo inowanikwa yenzira pachidimbu chimwe nechimwe) inoratidza kuti zvidimbu makumi maviri nemana hazvigone kugamuchira huwandu hwezviratidzo pahupamhi hwetrace hunodiwa uye nzvimbo inodiwa. Zvinokonzera zvinowanzo itika:

• Mapakeji eBGA anopfuura 2,500 pini ane 0.8 mm kana 1.0 mm pitch, uko nzira yekubuda nayo inoda masaini akawanda padivi rega rega repakeji.
• Mapakeji echip akawanda (MCM kana 2.5D interposer configurations) apo huwandu hweI/O huwandu hwacho hunodarika 24-layer routing capacity
• Nhamba dzezvinobatanidza zvinomhanya zvakanyanya dzinopfuura 64 differential pairs pa28 Gbps+, apo peya yega yega inofanira kufambiswa nematanho ekutarisa ari pamusoro nepasi pese pahurefu hwayo hwese.
• Nzvimbo dzemagetsi dzinopfuura 6-8 mukuoma, zvichida ndege dzakatsaurirwa dzemagetsi akawanda kudzivirira kubatana kweruzha rwepamwe chete.

Kana dhizaini yako isingasvike pane zviviri zvezvinodiwa izvi, ongororo yakarongwa yesarudzo dzine 24-layer yakakodzera kupedzwa usati waisa mari yekushandisa maturusi ane 28-layer uye mari yekugadzira.

1.2 Kubatsira Kwemachira Ane Makumi Maviri Nesere Pamusoro Pemachira Ane Makumi Maviri Nemana Nemakumi Matatu Nemaviri

Makumi maviri nemasere ezvikamu anopa mamwe mana ekuwedzera routing kana plane layers pamusoro pe 24-layer stackup ukuwo achiramba ari mu sequential lamination range iyo vatengesi vakawanda vanogona kutarisira (kazhinji 2-3 lamination cycles zvichienzaniswa ne 3-4 inodiwa kune 30+ layers). Zvichienzaniswa ne 32 layers, 28 layers dzinopa mutengo wakaderera wezvinhu (prepreg shoma uye core layers), pfupi sequential lamination nguva, uye goho repamusoro rekugadzira - ukuwo zvichisangana nezvinodiwa zve 400G networking, AI inference, uye advanced FPGA platform designs. Kunzwisisa mafambiro ese ePCB ekugadzira sequential lamination kunobatsira kuisa nguva chaiyo yekutungamira uye zvinotarisirwa nemutengo usati waburitsa RFQ.

2. Kuronga Kuronga Magadzirirwo Emapurani Ane Maturikidzwa Ane Maturikidzwa Ane Makumi Maviri Nesere

2.1 Nheyo dzeKupa Basa reMaraki

Kurongwa zvakanaka kwezvikamu makumi maviri nemasere kunotevera misimboti yekuvimbika kwezviratidzo iyo inova yakakosha zvikuru, kwete shoma, sezvo huwandu hwezvikamu huchiwedzera:

• Chiratidzo chega chega chinomhanya zvakanyanya chinofanira kunge chine chiratidzo chinoenderera mberi chiri pedyo nacho. Pama layer makumi maviri nemasere, hapana kushomeka kwema layer e plane — shandisa iwo kugadzira stripline environments yeboka rega rega re critical signal. Microstrip routing pa outer layer inofanira kuchengeterwa masignals apo controlled-impedance inodiwa yechipiri.
• Chengetedza kuenzanisa pakati pebhodhi. Kuunganidzwa kusina kuenzana — huremu hwakasiyana hwemhangura, ukobvu hwakasiyana hwe dielectric, kana huwandu hwakasiyana hwezviratidzo uye zvidimbu zvepakati pamativi ese epakati — kunoita kuti pave nekukombama kweneti pakati pebhodhi panguva yekukanda uye kupisa. Pazvikamu makumi maviri nemasere uye ukobvu hwakapedzwa hwe3.0–3.6 mm, warpage kubva kuzvikamu zvisina kuenzana yakaoma kugadzirisa uye inogona kukonzera kutadza kwekubatanidza. IPC Class 3 inoda bow and twist ≤0.5%.
• Boka mapuraneti emagetsi nemagetsi, uine zvikamu zvechiratidzo pakati pawo kana zvichibvira. Peya iri pakati pemasaini maviri inoshanda se capacitor inobvisa masaini ine inductance pfupi - mukana wePDN chaiwo. Gadzira stackup kuitira kuti geometry iyi ishandiswe kune nzvimbo dzine ruzha rwakanyanya.

Kuti BGA ikwanise kubhururuka zvakanaka ine ma layer makumi maviri nemasere, HDI kuburikidza nema structures — stacked microvias uye via-in-pad — zvinowanzodiwa. Izvi zvinoda mugadziri ane active sequential lamination line uye laser drilling ability, kwete kungokwanisa kuverenga layer count chete.

2.2 Kukora kweDielectric uye Zvinangwa zveImpedance

Pama layers makumi maviri nemasere, ukobvu hwe dielectric pakati pe ma signal layers ne reference planes avo hunowanzova mu 75–150 µm range ye inner stripline layers. Izvi zvinofambisa trace widths — 50 Ω single-end trace pamusoro pe 100 µm dielectric ine Er = 3.7 (Isola 370HR) inenge 170–180 µm yakafara, iyo inokwanisa kugadziriswa pakugadzirwa kwePCB kwemazuva ano inodzorwa ne impedance . Kune 100 Ω differential pairs, trace width uye spacing combination inofanira kuratidzwa ne field solver yemugadziri uchishandisa actual stackup geometry — kwete kufungidzirwa kubva kuma calculator epamhepo.

Dielectric dzakatetepa (75 µm kana pasi) dzinoita kuti pave nekubatana kwakasimba pakati pema differential pairs uye parasitic capacitance yakaderera pama high-speed nodes, asi dzinoda mugadziri ane kugona kwakaratidzwa kwekubata dielectric thickness tolerance (±10% ye nominal after lamination ndiyo inodiwa neIPC Class 3). Pa 75 µm nominal, ±10% zvinoreva ±7.5 µm — tolerance inoda kuti mugadziri atsanangure prepreg resin flow chaiyo yekubatanidza kwega kwega uye resipi ye lamination.

3. Kuvimbika kweSignali pa28 Gbps zvichikwira

3.1 Bhajeti rekurasikirwa kwekuisa mabhodhi ane zvidimbu makumi maviri nemasere

Kubudirira pakushanda kwechiratidzo che high-frequency chinoda 28 Gbps+ serdes links kunoda kusarudzwa kwezvinhu zvakanyatsonaka uye kutsanangurwa kwe copper foil usati waisa chando. Chiratidzo che 28 Gbps NRZ (14 GHz fundamental) chinoyambuka 300 mm board pane inner stripline layer chinosangana nekurasikirwa kwe conductor, kurasikirwa kwe dielectric, uye kuburikidza nekurasikirwa. Mubhodhi re 28-layer uchishandisa Isola 370HR ine standard copper:

• Kurasikirwa kwemutyairi (copper yakajairwa yeED): inenge 0.18–0.22 dB/cm pa14 GHz
• Kurasikirwa kweDielectric (Df = 0.021 pa10 GHz): inenge 0.12–0.15 dB/cm pa14 GHz
• Kurasikirwa kwechiteshi chakabatanidzwa kwe300 mm: 9–11 dB, usati watanga kuburikidza nemipiro

Bhajeti iyi haina kukosha pa28 Gbps NRZ pasina equalization. Kune magadzirirwo anoda kurasikirwa kwakaderera - kana kuti PAM4 signaling pa56 Gbps (28 Gbaud) uko bhajeti yekurasikirwa iri shoma - Panasonic Megtron 6 (Df = 0.002) ine VLP copper inoderedza kurasikirwa kwakabatana kusvika pa5–6 dB kune hurefu hwechiteshi chimwe chete, zvichipa mukana wakakura wekuenzanisa uye kuvimbika kwesystem.

Zvinoreva kuti: sarudzo yezvinhu zvekugadzira dhizaini ine 28-layer pa28 Gbps+ haisi sarudzo yechipiri. Inofanira kuitwa pakutanga kwekugadzira, zvichikonzerwa nebhajeti rekurasikirwa kwechiteshi kubva pamuenzaniso we pre-layout, uye kuvharwa mugadziri asati asarudzwa — nekuti havasi vese vagadziri vane 28-layer vanogara vachigadzira Megtron 6.

3.2 Kuburikidza neDiscontinuity uye Back-Drilling pa28 Layers

Kupinda-pinda mubhodhi rine zvidimbu makumi maviri nemasere rinongoshandiswa chete pachikamu chidiki cheukobvu hwebhodhi kunosiya stub inorira mukati mebandwidth yechiratidzo. Kune bhodhi rine zvidimbu makumi maviri nemasere rine ukobvu hwakapedzwa hwe3.2 mm apo via inobatanidza zvidimbu 1–14 chete, stub isina kushandiswa inenge 1.6 mm - ichirira pa30 GHz. Kune 28 Gbps NRZ signals dzine simba re14 GHz, iyi resonance iri pamuganhu we harmonic; kune 56 Gbps signals, iri zvakananga mu-band.

Kuboorera kumashure kunobvisa zvisina kushandiswa kuburikidza nestub, zvichisiya zvasara zvinodzorwa zviri ≤0.25 mm. Maitiro aya anoda kuboorera kwemuchina kunodzorwa zvakadzama ne ±50–75 µm Z-axis accuracy uye dhigirii remubhadharo rakagadziriswa kuhukobvu hwebhodhi rega rega. Kumbira mifananidzo yezvikamu zvakasiyana-siyana zvemavias akaboorwa kumashure kubva mukugadzirwa kwazvino kwemugadziri - kureba kwestub kwakayerwa kunoonekwa zvakananga muchikamu uye ndiyo yekusimbisa yakavimbika kugona kwavo kwekugadzira back-drill.

4. Magadzirirwo eNetwork yeKuendesa Simba muMabhodhi ane Zvikamu makumi maviri nemasere

4.1 Kuwanda Kwenzvimbo uye Kuparadzaniswa Kwenzvimbo Dzesimba

Dhizaini ine zvidimbu makumi maviri nemasere inowanzo patsanura zvidimbu gumi kusvika gumi nemana kumapuranga (simba nepasi zvakabatana) uye zvidimbu gumi nemana kusvika gumi nesere kuti zviratidze nzira yekufambisa. Kuwanda kwemapuranga aya kunoita kuti simba rechokwadi rive rakasiyana: mapuranga akasiyana akatsaurirwa emagetsi epakati, magetsi eI/O, analog supply, magetsi ekumisa DDR, uye masimbi ekubatsira - imwe neimwe ine nzira yayo yekudzoka uye nzira yekubatanidza. Imwe nzira - mapuranga akagovaniswa ane mapombi emhangura akapatsanurwa - anounza kubatana kwakakwira pakati pemasimba emagetsi akaoma kutevedzera uye akaoma kubvisa muhurongwa huripo.

Kune mabhodhi eAI data center uye mapuratifomu e networking emhando yepamusoro apo makumi emaampere ari pa sub-1V core voltage anofanira kuendeswa ne millivolt-level ripple, dhizaini yePDN yakagadzirwa pamwe chete ne stackup. Ma plane pairs akasarudzwa e core voltage anofanira kuzivikanwa usati watanga kuiswa, kwete kugoverwa kune chero layers inosara mushure mekunge signal routing yapera.

4.2 Kuisa Capacitor muDecoupling uye Via Stub Effects

Ma capacitor anodhonza akaiswa pamusoro pebhodhi anofanira kubatana nemagetsi nepasi kuburikidza nezvivakwa. Via imwe neimwe inounza inductance — inenge 0.5–1.0 nH ye standard kuburikidza ne 3.2 mm board. Pa 28 layers apo power planes dzinogona kunge dzakadzika mu stackup, via inductance kubva pa surface-mounted dracoupling capacitor kuenda ku power plane yakakodzera inogona kunge yakakosha zvakakwana kuderedza kushanda kwe capacitor pamusoro pe 100–200 MHz. Kuderedza izvi kuburikidza ne inductance kunoda kushandisa via arrays (multiple vias in parallel) uye kuisa dracoupling capacitors pa layer iri pedyo ne component yavanoshandira — izvo pa 28 layers zvinowanzoreva kuaisa mu stackup pa intermediate lamination stage.

5. Kushandura Zvinodiwa zveSI kuita Zvidimbu zveKugadzira

5.1 Zvinhu Zvinofanira Kutsanangurwa Zvinofanira Kujeka

Odha yePCB ine 28-layer yakarongwa iyo inotsanangura chete data reGerber uye huwandu hwelayer haisi iyo specification yekugadzira. Zvinhu zvinotevera zvinofanirwa kunyorwa zvakajeka:

• Zvinhu zvakanyungudutswa zvichienderana nemugadziri, giredhi, uye zita reIPC-4101 re slash sheet (semuenzaniso, “Isola 370HR, /126”)
• Rudzi rwefoiri yemhangura nehuremu zvichienderana neboka remachira kana machira (semuenzaniso, “VLP copper, 0.5 oz pazvikamu zvemukati zvesignal L3–L26”)
• Zvinangwa zve impedance zvinodzorwa zvine kirasi ye net, kugoverwa kwe layer, uye tolerance (semuenzaniso, “100 Ω differential, L5/L6 pair, ±5%”)
• Zvinodiwa zvekuboorera kumashure: izvo kuburikidza nemapoka, kutungamira kwekuboorera, kureba kwakanyanya kwestub
• Kirasi yeIPC: zvakajeka kuti “IPC-6012 Kirasi 3” — musasiya izvi zvisina kutaurwa
• Kupera kwepamusoro nehukuru hwakatsanangurwa (semuenzaniso, “ENIG, 2 µin Au minimum / 150 µin Ni”)
• Zvinodiwa pakuyedza: 100% flying probe kana fixture electrical test, TDR impedance coupon test papaneru imwe neimwe

5.2 Ongororo yeDFM seChiitiko cheKukodzera Mupi weMutengesi

Kumbira kuti mugadziri aongorore DFM usati wabvumidza kugadzirwa. Mugadziri ane hunyanzvi hwemachira makumi maviri nemasere acharatidza matambudziko chaiwo: kutyorwa kwemaringi eannular pa high-aspect-ratio vias, kusawirirana kwekubvisa madhiri kumashure, matambudziko e copper balance anofungidzira warpage, kana matambudziko ekusarudza prepreg pa thin dielectric targets. Mugadziri anodzosera DFM review asina mashoko pamusoro pedhizaini yakaoma ye 28-layer haana kuongorora mafaira kana kuti haana mainjiniya anokwanisa kuaongorora. Zvese zviri zviviri zvinofanirwa kuita kuti mupi wemuchina asakodzere.

6. Kuongorora Mupi wePCB ane 28-Layer: Humbowo Hunokosha

6.1 Matrix yeUchapupu hweMutengesi

6.2 Zviratidzo Zvisina Kunaka Panguva Yekuongorora Kwemutengesi

• Mutengesi haakwanise kugadzira mifananidzo yezvikamu zvakasiyana kubva mukugadzirwa kwezvikamu makumi maviri nemasere mumazuva makumi mapfumbamwe apfuura - zvinoreva kuti 28L haisi kugadzirwa kwavo.
• Impedance data reCpk harisipo kana kuti rinoratidza Cpk <1.33 — rinoratidza kusakwana kwekutonga kwemaitiro ekutsungirira ±5%
• Mutengesi haashandisi muchina wekugadzirisa nharaunda (Polar SI, iCD, kana yakaenzana) pakuverenga impedance - zvinoreva kuti upamhi hwetrace hwakafungidzirwa, kwete hwakaitwa modeled
• Kugadziriswa kweongororo yeDFM kuri pasi pemaawa mana ekugadzira dhizaini yakaoma ye28-layer - zvinoratidza kuti mafaira haana kuongororwa neinjiniya.
• Mutengesi haakwanise kudoma kemikari yeplating inoshandiswa pa high-aspect-ratio vias - zvinoratidza kusaziva zvinodiwa zveClass 3 plating

Kurukurai nezvePurojekiti Yenyu yePCB ine Zvikamu 28

7. Nguva Yekutungamira, Zvinokonzera Mutengo, uye Kuchinja Kwemuenzaniso-Kubva-Kugadzira

7.1 Nguva Yechokwadi Yekutungamira KwemaPrototype ePCB Ane Maturikidzwa makumi maviri nemasere

Chigadzirwa chemhando ye28-layer chinogadzirwa nemugadziri ane hunyanzvi chinotora mazuva gumi nemashanu kusvika makumi maviri nemashanu ekushanda kubva pakubvumidzwa kweDFM kusvika pakuendeswa. Nguva yekutanga inodzorwa nehurongwa hwe sequential lamination (kutenderera kwega kwega kunoda nguva yekudzvanya, nguva yekuporesa, uye divi rimwe chete risati ratanga) uye plating sequence (PPR plating ye high-aspect-ratio vias inoda nguva yakareba yekugeza zvichienzaniswa neDC plating). Chero mutengesi anoti 28-layer prototype delivery inotumirwa mumazuva mashanu kusvika manomwe anofanira kubvunzwa zvakananga kuti vanopedzisa sei 3 lamination cycles munguva iyoyo - fizikisi haitsigire.

Pamabhodhi akawanda ekugadzira 50–500, nguva dzekutanga dzemazuva ebhizinesi 20–30 dzinowanikwa kune vatengesi vane hunyanzvi, uye kuwanikwa kwezvinhu ndiko kunonyanya kusiyanisa. Mutengesi ane Isola 370HR neMegtron 6 muhukobvu hwakajairika anogona kutanga kugadzirwa zuva rabvumidzwa neDFM; mutengesi anoraira zvinhu pabasa anowedzera vhiki imwe kusvika nhatu kune odha yega yega.

7.2 Magadzirirwo emutengo wePCB ine 28 Layer

Zvinhu zvinonyanya kukonzera mari muPCB ine 28-layer, zvichienderana nekurova:

• Mari yezvinhu: 30–40% yemari yese yebhodhi. Megtron 6 inodhura 4–6× kupfuura Isola 370HR pachikamu chimwe nechimwe. Musiyano uyu wemutengo unofanirwa kusimbiswa nekuongorora kweSI, kwete kungofungidzirwa kuti "zvinhu zviri nani zviri nani."
• Sequential lamination labor uye press time: Kutenderera kwega kwega kwe lamination kunowedzera mutengo wakananga uye kunowedzera nguva yekutangira. Magadzirirwo anogona kuvakwa mumatanho maviri panzvimbo pematatu akachipa zvikuru - sarudzo dzekuvaka dzakaitwa pakutanga kwekugadzira dzinokanganisa mutengo zvakanyanya.
• Kuboorera shure: Inowedzera mutengo kuburikidza neboka rega rega rinoda kuboorwa, pamwe nenguva yakareba yekutenderera. Kuboorwa shure kunofanirwa kushandiswa nenzira yekusarudza - chete kuburikidza nemapoka apo stub resonance iri mukati mebandwidth yechiratidzo, kwete kune ese ma through-vias.
• Surface kupera: ENIG inowedzera mutengo wakaderera kana tichienzanisa nehukuru hwebhodhi rine 28-layer. ENEPIG yekushandisa waya kana goridhe finger inoda inowedzera. Taura zvinodiwa, asi usabva wangoisa mari inodhura zvakanyanya pasina chikonzero chekushandisa.

7.3 Kutarisira Kuchinja Kwemuenzaniso-Kuenda-Kugadzirwa

Musiyano uripo pakati peprototype inobudirira nekugadzirwa kunodzokororwa ndipo panosangana matambudziko akawanda mapurogiramu ane layer 28. Prototype iyi yakavakwa nekutarisirwa kwakanyanya kweinjiniya; production lot inoshanda mu batch mode ine standard process flow. Kuchengetedza mhando yekugadzira:

• Kumbira data reCpk re impedance kubva ku pre-production lot — kwete kubva ku prototype chete
• Gadzira chibvumirano chekukiya maitiro chinotsanangura kwakabva laminate lot, parameters dzeplating, uye lamination profile usati watanga kugadzira.
• Taura 100% kuongorora magetsi — flying probe kana fixture — sechinodiwa muchibvumirano muchirevo chekutenga, kwete chikumbiro chakasiiwa kusarudzo yemugadziri
• Gadzirisa Pcb gungano zvinodiwa nekutsungirira kugadzirwa nekukurumidza: sarudzo yekupedzisa pamusoro, kuburikidza nezvinodiwa zvekuzadza, uye kutsetseka kwebhodhi kunokanganisa zvakananga goho reSMT riri pasi, uye izvi zvinofanirwa kusimbiswa pakati pezvikwata zvekugadzira nekugadzira usati waburitsa lot yekutanga yekugadzira.
• Tsanangura maitiro ekugadzirisa muchibvumirano chemhando yepamusoro usati wagadzira lot yekutanga — kwete mushure mekukundikana kwekutanga