Low Transmission Loss Multilayer PWB Materials for High-Speed and High-Frequency Applications. Yasuyuki Mizuno

Transcription

1 63 rd IEEE ECTC Las Vegas, NV: Low Transmission Loss Multilayer PWB Materials for HighSpeed and HighFrequency Applications Hitachi Chemical Co., Ltd. Tsukuba Research Laboratory Telecommunication Materials Development Center 1

2 Introduction Evaluation technologies of highfrequency performance by Hitachi Chemical Properties of new midloss PWB material Innovative ultralow loss PWB material / Target & Technical concept / Features & Advantages Conclusions Outline 2

3 Background ; Trend of transmission rate Higher performance of communication on network platform 1P 100T 10T 1T Throughput of equipment Double / 2 years (Predicted from telecommunication traffic) 100G Standardization 10G 25 Gbps /link Applications ('14'15) 1G Transmission rate of PWBs / Link Double / 3years) 100M '96 '98 '00 '02 '04 '06 '08 '10 '12 '14 '16 '18 '20 Signal speed on PWBs is increasing year by year to meet the needs of largevolume data transmission. 3

4 Transmission rate (Gbps / link) Transmission rate vs. trace length on PWBs Boundary of electrical / Optical 50 LSI Next generation transmission technology (25 Gbps / link) Electrical? or Optical? or Both 10 BGA, CSP MCM (SiP) Electrical field Trace length on PWBs (m) Daughter Board Backplane (Midplane) Optical field Need of the lower loss PWB material is increasing for the next generation electrical transmission. Optical fibercable Cabinet to Cabinet 4

5 Requirement for Highfrequency PWB material Transmission loss (α) Dielectric loss (αd) + Conductor loss (αc) f αd 27.3 Dk Df c αc Rs ( f, ρ, ) Dk (t, w, b,) b t w αd αc Dk : dielectric constant, Df : Dissipation factor f : Frequency, c : Light velocity Rs : Surface resistance of conductor ρ : Resistivity of conductor, b : Dielectric thickness w : Conductor width, t : Conductor thickness < Solution to lowering transmission loss > Reduction of ad Low Dk & Df Resin technology Reduction of ac High adhesion technology between resin and conductor with very low surface roughness 5

6 Evaluation technologies of highfrequency PWBs Hitachi Chemical can satisfy various evaluation requirements of highfrequency performance of materials & PWBs (e.g. Frequency bands, Form of specimen, Environmental test, etc.) (1) Dielectric properties of materials (without conductor) Parallel plate capacitance Cavity resonator perturbation Split post dielectric resonator(spdr) Whisperinggallery mode(wg) Under planning Frequency [GHz] (2) Practical electrical properties of PWBs (containing conductor) Stripline resonator(jpcatm001) Short pulse propagation(spp) Under planning Strip line(sl) Micro stripline(msl) Dk & Df Dk & Df Transmission loss Frequency [GHz] 6

7 Evaluation of PWB (SL & MSL) Strip line(sl) structure SMA connector type (up to 20 GHz) Test board (SL) Probe type (up to 40 GHz) Micro strip line(msl) structure S 11 S 21 VNA & Probe station Test board (MSL) Measurement system Connector available After treatment (85 /85 %RH) e.g.) High Tg material for PKG substrate Initial Probe available PTFE material Low Df material (FX2) Various highfrequency properties of PWBs can be evaluated. 7

8 Simulator 3D EM field solver (HFSS) Circuit simulator (ADS) HFSS : HighFrequency Structure Simulator ADS : Advanced Design System Simulation technologies Guessing of electrical performance, combination of structures, and the suitable materials Designing of PWB structure (e.g. measurement terminals, etc.) for evaluation of transmission properties to Wband, 100 GHz Verification of the measured Df value by fitting calculated transmission loss, S21, to measured loss S21 Guessing of dielectric drift properties, Dk, by fitting calculated resonance properties, S11, to measured S11, etc. Resonance pattern Measurement terminal MSL Verification of the measured properties, Dk & Df by using simulation, & feedback of them to the material design. SL 8

9 Df (10 GHz) HC's highlayer & highfrequency materials lineup Midloss material, HE679G(S), and ultralow loss material, LW900G have been newly developed. HE679G HighTg & LowCTE FR4 (E679FJ) HighTg FR4 (E679) New midloss material HE679G(S) Dk (10 GHz) Conventional FR4 (E67) FX2 Mid.loss grade Standard grade Ultralow loss grade Low loss grade New ultralow loss material LW900G 9

10 Item Laminate properties of new midloss material New midloss HE679G(S) Current HE679G HighTg FR4 Conventional FR4 Glass type E E E E Source of flame retardant Halogen free Halogen free Halogen Halogen Dk (JPCATM001) 1 GHz GHz Df (JPCATM001) 1 GHz GHz Copper peel strength (kn/m, 1/2 oz) Standard RTF Tg ( ) TMA CTE(ppm/ ) XY Z(α1) Z(α2) Solder heat resistance 288 > 300 s > 300 s > 300 s > 300 s T300 TMA > 60 min 30 min <10 min <5 min Flammability UL94 V0 V0 V0 V0 Reliability(CAF, IST, etc.) Good Good Low NG Dk & Df of the newly developed midloss material, HE679G(S), have been enhanced with maintaining the other properties as HE679G

11 Transmission loss of new midloss material < Measurement conditions > / Evaluation structure : Stripline / Temperature & Humidity: 25 /60 %RH / Characteristic impedance:ca. 50 Ω / Interlayer surface treatment: Blackreduction / Proofreading method: TRL / Dimension parameters P/P w t b Core Trace width(w): mm Dielectric thickness(b): mm Trace thickness(t): 18 μm TEG PWB New mid.loss material HE679G(S) Current HE679G HighTg FR4 Transmission loss of HE679G(S) has been improved, comparing with the current HE679G. 11

12 Heat resistance Reliability of new midloss material <Evaluation conditions > / Test board : t2.47 mm / 20 layer PWB / Diameter : Φ0.25 mm (THTH pitch : 0.8 mm) / Precondition : 85 /85 %RH/120 h + Reflow max times CAF Test <Evaluation conditions > / Test board : t1.4 mm / 2 layer PWB / THTH spacing: 0.5 mm / 2000 holes / Precondition : 30 / 60 %RH / 168 h + Reflow max times / Measurement condition : 85 /85 %RH, DC 100 V) (Measurement of insulation resistance in chamber) New mid.loss material HE679G(S) Current HE679G Passed (No defect) Excellent reliability as that of the current HE679G 12

13 Highlayer reliability Target properties of new ultralow loss material HFPerformance vs. Reliability(Heatresistance, CAF, IST, ) E679FJ E75G HE679G New Target FX2 LZ71G E679 LX67Y E67(Conventional FR4) BE67G(H) PTFE laminate Grade Standard Midloss Low loss Ultralow loss (Df@10 GHz) (>0.02) ( ) ( ) (Df:<0.005) Highfrequency performance Target of new ultra low loss material is the compatibility of highfrequency performance & reliability of highlayer PWBs. 13

14 Concept & target applications of new ultralow loss material Development concept Reliability & Processability Highfrequency performance Halogen free Target applications & requirement Highspeed Digital / Highlayer (Servers, Routers, HPC, etc.) High frequency performance High heat resistance High reliability(lowcte,caf, etc) RF / Wireless (Antenna, RFmodules, etc.) High frequency performance Dk & Df drift stability (Temperature, Humidity) Highspeed PKG (MMICPKG, OEICPKG, etc.) High frequency performance High heat resistance High reliability(lowcte,caf, etc) Halogen free 14

15 Technical composition of novel resin system designed for new ultralow loss material Rigid thermosetting resin Low Df High Tg Polymerblend modification technology Low CTE with cocrosslinking reaction High elastic modulus High heat resistance High flame retardancy Low CTE Low Df High heat resistance Low water absorption Reactive low polar polymer Composing technology (Organic / Inorganic) by controlling interface between resin and filler Inorganic filler Low Dk & low Df High Tg Low water absorption High toughness High adhesion New material has been designed by using both the resinmodification technology & fillercomposition technology. 15

16 Conventional Aggregation Filler / Resin composing technology Filler interface control system (FICS) Matrix resin Inorganic Filler Optimization of interface(filler / Resin) Excellent adhesion & dispersion / Low water absorption / High peel strength / Excellent heat resistance / Excellent CAF restraining property Example of importance of FICS Exfoliation mode on Cupeeling test None Exfoliation between filler & resin Optimum (FICS) The control of interface between resin and filler is important to enhance various properties. Optimum Cohesive failure of resin 16

17 Laminate properties of new ultralow loss material Item New ultralow loss LW900G Current low loss FX2 HE679G Standard PTFE laminate Resin system Thermosetting Thermosetting Thermosetting Thermoplastic Glass type E NE (Low Dk) E E E Source of flame retardant Halogen free Halogen Halogen free Dk (JPCATM001) 10 GHz Df (JPCATM001) 10 GHz *1) *1) Copper peel strength (kn/m, 1/2 oz) RTF HVLP *2) (Std.foil) Tg ( ) TMA CTE(ppm/ ) XY Z(α1) Z(α2) Solder heat resistance 288 > 300 s > 300 s > 300 s > 300 s > 300 s T300 TMA > 60 min > 60 min > 60 min 20 min Flammability UL94 (V0) (V0) V0 V0 V0 Reliability(CAF, IST, etc.) On internal evaluation On internal evaluation On evaluation by PWB maker Good *1) Practical value calculated by the condition of stripline structure with Cufoil(RTF, Rz 3 μm) *2) Practical value calculated by the condition of stripline structure with Cufoil(HVLP, Rz 1.5 μm) 17

18 Dk & Df vs. Frequency < Measurement conditions > / Method : Stripline resonator (JPCATM001) / Temperature & Humidity : 25 / 60 %RH / Dielectric thickness : 1.6 mm(ground Ground), Copper foil : 18 μm LW900G (NEglass, RTF) LW900G (Eglass, RTF) FX2 LW900G (NEglass, HVLP) LW900G (Eglass, RTF) FX2 LW900G (NEglass, RTF) Standard PTFE laminate LW900G (NEglass, HVLP) Standard PTFE laminate Excellent stability of Dk in wide frequency range Df of standard type is lower than the current low loss material(fx2). Df of lowdk type with HVLP is better than that of PTFE laminate. 18

19 Dk & Df vs. Temperature < Measurement conditions > / Method : Stripline resonator (JPCATM001) / Temperature : 25~100 / Dielectric thickness : 1.6 mm(ground Ground), Copper foil : 18 μm LW900G (Eglass, RTF) FX2 LW900G (NEglass, RTF) LW900G (Eglass, RTF) FX2 Standard PTFE laminate LW900G (NEglass, RTF) Standard PTFE laminate Excellent stability against temperature change 19

20 Dk & Df vs. Moisture absorption < Measurement conditions > / Method : Stripline resonator (JPCATM001) / Moisture absorption treatment : 85 /85 %RH/1000 h / Dielectric thickness : 1.6 mm(ground Ground), Copper foil : 18 μm HighTg FR4 HighTg FR4 LW900G (Eglass, RTF) FX2 LW900G (NEglass, RTF) LW900G (Eglass, RTF) LW900G (NEglass, RTF) FX2 Better stability against moisture absorption treatment compared with hightg FR4 20

21 Transmission loss of new ultralow loss material < Measurement conditions > / Evaluation structure : Stripline / Temperature & Humidity: 25 /60 %RH / Characteristic impedance:ca. 50 Ω / Interlayer surface treatment: Blackreduction / Proofreading method: TRL / Dimension parameters P/P w t b Core Trace width(w): mm Dielectric thickness(b): mm Trace thickness(t): 18 μm TEG PWB Improved by 8 db/m(12.5 GHz) compared with current low loss material 25 db/m@12.5 GHz HVLP(Rz 1.5 μm) 33 db/m@12.5 GHz RTF(Rz 3 μm) 21

22 Verification procedure Verification of Df by simulation (1) Calculating of the conductor loss(αc) in the case of HVLP foil by using simulator (HFSS) (2) Calculating of Df which fitting dielectric loss(αd) to the loss value which subtracted simulated αc from the measured actual total loss(s21) (Df αd =S21αc) Calculated conductor loss (αc, HVLP : Rz 1.5 μm) Simulated αd When Df is @10 GHz, αd fits to (S21αc) Measured total loss(s21) (LW900G, NEglass/HVLP) Df@10 GHz=0.0035(NEglass/HVLP foil) was verified by simulation(hfss), too. 22

23 Voltage (mv) Voltage (V) Voltage (mv) Voltage (mv) Voltage (mv) Voltage (mv) Voltage (mv) Voltage (mv) Voltage (mv) Voltage (mv) Voltage (mv) Voltage (mv) Eye pattern diagrams < Measurement conditions > / Evaluation PWB : Former S21 evaluation PWB(Stripline ) / Bit rate : 12.5 Gbps (Trace length : 300 mm), 25 Gbps (Trace length : 100 & 300 mm) Item HE679G FX2 LW900G(Eglass) LW900G(NEglass) 12.5 Gbps L:300mm Time (ps) Time (ps) Time (ps) Time (ps) 25 Gbps L:100mm Time (ps) Time (ps) Time (ps) Time (ps) 25 Gbps L:300mm Time (ps) Time (ps) Time (ps) Time (ps) Eyeopening of LW900G is better than the others. 23

24 Insulation reliability(caf evaluation) < Evaluation conditions > / Evaluation board : t0.8 mm(cu:18 μm) / 2 layer PWB / Diameter : Φ0.15 mm / THTH spacing : 0.2 mm / Precondition : 85 /85 %RH/120 h + Reflow max times / Measurement condition : HAST(130 /85 %RH), DC 5.5 V (Continuous measurement of insulation resistance in chamber) Diameter:φ0.15 mm TH TH spacing:0.2 mm LW900G HighTg FR4 HE679G Conventional FR4 Crack (glass/resin) by drilling : <10~20 μm Excellent CAF restraining property & drilling processability 24

25 Features & Current status of new ultralow loss material (LW900G) Features of LW900G GHz Eglass type : Lower than current low loss material(fx2) LowDk type : same or better compared with PTFE material Thermalmechanical properties(tg,cte,etc) Better than FX2 Heat resistance Excellent Flame retardancy V0 by Halogenfree resin system Reliability of highlayer PWB (CAF, TCT, IST, etc.) On evaluation Drilling processability of highlayer PWB On evaluation Ongoing study Optimization of mass production process Reliability test & processability test of highlayer PWB Further improvement of dielectric properties for the next generation material (Df Target : < 0.002@1020 GHz) 25

26 Road Map of HC's highfrequency Materials Applications Highend digital (Highspeed & Highlayer) Middle~Std. digital RF/Wireless (Analog high Freq.) Highspeed PKG Buildup material for PKG Transmission rate/link 300 Mbps~1 Gbps 1.25~2.5 Gbps 3.2~6.4 Gbps ~12.5 Gbps >25 Gbps (Backplane) (Mobile) <2.4 Kbps 9.6 bps~144 Kbps 2 Mbps 3.8 Mbps 5.7 Mbps 7.2 Mbps >12 Mbps Router Server Storage Transport HPC Measurement equipment ICtester, etc. Antenna Sensor RFModule Base station Mobile devices PC/Server Mobile devices RFModule MMICPKG PC/Server Mobile devices RFModule MMICPKG ~ Dk<3.8/Df<0.005 LX67/LX67Y Dk:3.5/Df:0.005 E67/E679 Dk:>4.0/Df:>0.02 HD67 Dk:10.2/Df:0.009 LZ71G Dk:3.6/Df:0.006 Dk<4.5/Df<0.025 Dk<4.5/Df<0.018 Df<0.01 E679FJ Dk:4.3/Df:0.018 Df<0.015 Df<0.005 LX67F Dk:3.7/Df:0.003 E679F/E679FG Dk:4.5/Df:0.014 Dk<3.7/Df<0.003 Dk<3.3 Df<0.002 FX2 LW900G New Dk:3.5/Df:0.003 Df:0.002 Df:<0.002 Dk<4.0/Df<0.01 Dk<3.8 Df<0.007 HE679G HE679G(S) New Dk:4.0/Df:0.009 Df:0.006 Df:<0.005 Dk<3.5 Dk<3.3 Df<0.003 Df<0.002 FX2/FX3 Dk:3.23.5/ Df: LZ71G Dk:3.6/Df:0.006 Df<0.02 ASZ2 Df:0.015 Df<0.01 E800G LW900G Dk:4.0/Df:0.005 Df:0.002 ASZ3(K) Df:0.013 Dk&Df: value of 1GHz Df<0.005 Df<0.015 Df<0.005 ASZ5 Df:

27 and do not represent a guarantee of the values for each property. Conclusions We have lined up low transmission loss PWB materials for highspeed and highfrequency applications. The new midloss material, HE679G(S) has lower Dk and Df than current material, HE679G, and has the excellent reliability as HE679G. Novel low loss and halogen free thermosetting resin system has been designed for the next generation highspeed applications. Innovative ultralow loss material, LW900G with the novel resin technology shows lower Df than standard PTFE laminate, which is characterized by high Tg, low CTE, high heat resistance, the excellent CAF property, and the processability almost similar to FR4. Note: The contents of this report are based on the results of experiments 27

28 63 rd IEEE ECTC Las Vegas, NV: Thank you for your attention! 28