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Isola Technology and Product Update June 2005. Isola Technology Agenda. Isola Product Technology Roadmap Isola Lead Free, FR4 Replacement Product Solutions Isola High Speed, Signal Integrity Product Solutions Reliability Overview of Isola Test Capabilities .
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Isola Technology and Product Update June 2005
Isola Technology Agenda • Isola Product Technology Roadmap • Isola Lead Free, FR4 Replacement Product Solutions • Isola High Speed, Signal Integrity Product Solutions • Reliability • Overview of Isola Test Capabilities
Emerging Trends Signal Integrity Lead Free High Speed Digital - High Gbps Data rates. - High Clock speeds Optical Solutions - 5-10 Gbps data rates and beyond Lead free and Thermal Reliability Higher Thermals Higher Thermal Cycling resistance Miniaturization - Thinner Dielectrics - Embedded passives - Packaging Thermal Management - Thermal conductive Substrates Environmental - Halogen Free Manufacturing and Process Technology
Isola’s Product offering- High Tg High performance T288 -60 Mins/Td.400** P95 260 Tg Polyimide HB L e a d Free IS625 P96 260 Tg Polyimide V0/V1 IS500 Military/Computers/drilling IS415 T260 -60 Mins/Td.350** IS420 IS620 Tg 215 Low Loss .008 @10 Ghz Laminate IS640 Next Generation Low Loss-.005 IS410 180° Tg FR408 180Tg Low Dk & Df Thermal Performance T260/ Decomp./IST G200 BT Epoxy Laminate High Speed Digital / Base stations/Routers/Servers/Burn in Higher Reliability High Speed /High Frequency T260 -10 Mins/Td.300** FR406 High Tg 170° Epoxy Telecom 2.5-10 Gbps* Low Freq and speed 1.5-2.0 Gbps * 1 -1.5Gbps * Electrical Performance Loss /DK * Speeds a function of design such as line length etc. **Laminate Data- IST performance is a function of Hole dia/board thickness,plating parameters and laminate attributes.
Isola Product Offering Tg 260 Polyimide Laminate V0/V1 P96 IS640-300 Low Loss Tg 260 Polyimide Laminate HB P95 Next Gen Low Loss -.0035 @10GHz- IS640 R F & M I C R O W A V E IS640-320 Low Loss Performance Tg 215 Low Loss .008 @10 Ghz Laminate IS620 IS640-325 Low Loss BT / Epoxy Laminate G200 IS640-338 Low Loss Tg 180 Low Dk & Df FR408 High Tg Lead free Signal Integrity Thermal Conductive IS415 IS450 IS640-345 Low Loss IS420/IS410 High Tg Lead free High Reliability Chip Packaging IS420 High Tg 170° Epoxy FR406/DE117 Low Flow No Flow High Tg 180° Halogen free FR406 NF/A11 IS500 Tg 150 Halogen Free Laminate DE156 FR406BC IS410 BC FR408 BC Buried Capacitance Applications Tg 140 Multifunctional FR402/DE114 Tg 130 FR-4 Multifunctional Tg 150 Lead Free High Reliability ED130UV IS400 FR-4 ED130 Application
Signal Integrity- Overview • Drivers • Overview of Technical issues • High Speed Basics • Key definitions • Measurements • Time domain measurements • Losses • Dielectric losses • Conductor losses • Conductor roughness losses • Frequency domain measurements • Isola offering • Product selection criteria
High Speed Digital basics • High Speed digital communication involves sending bits of information coded on Trapezoidal waveforms. • The Information - Zeros and ones are coded on the rise time or on both the rise time and fall time. • High Voltage is 1 and Low voltage is zero • The conductive paths between a chip that sends a signal to the chip that receives a signal are called interconnects, A group of interconnects represents a bus • The sharper the Rise time the faster the signal • To achieve faster rise times Sinusoidal wave forms are superimposed on one another. • The range of frequencies used is called bandwidth • The bandwidth is given as =0.35/Rise time • Example a 2.5 Gbps signal with a rise time of 70 Ps will have a fundamental frequency = 1.25 Ghz and a second cut off frequency of 4.5 Ghz and a 2.5 Gbps signal with a rise time of 125 Ps will have a fundamental frequency equal to 1.25 Ghz and a bandwidth or second cut off frequency = 2.5 Ghz. Frequency is a function of Data rate and bandwidth is a function of Rise Time
Time-domain definition of a periodic digital clock signal with analog definitions of rise time, fall time, and duty cycle. From Practical RF circuit Design for Modern Wireless systems Vol1 – Les Besser and Rowan Gilmore
Digital detector output signal - eye diagram - shows the effect of random jitter. A large eye amplitude and small difference between bit window and eye duration are necessary for low bit error rate.
Noise One Bit Length The “Eye” Good Sampling Period Jitter Signal with Noise Noise Margin Eye Pattern Analysis • Height of the central eye opening measures noise margin in the received signal • Width of the signal band at the corner of the eye measures the jitter • Thickness of the signal line at the top and bottom of the eye is proportional • to noise and distortion in the receiver output • Transitions between the top and bottom of the eye show the rise and fall • times of the signal Reference: Handbook of Fiber Optics
A 10 Gbps signal at source The effect of Laminate substrate on Signal integrity After 40 inches through IS640 After 40 inches through 406
Isola Products and Signal integrity in time domain Simulated Eye Diagrams @ 5 Gbps -1 M -50 Ohms impedance 5 Mil Track width PRBS 35 PS Rise time At Source Zero Dielectric Loss IS640 Df =.004 IS620 DF=.008 FR408 DF=.012 FR4 Df =.020
High Speed Digital Drivers • Trends • Rising Bandwidths- Bandwidth Approx.=0.35/Rise time • Faster edge rates ----> 35 PS and lower • High Data rates 10 Gbps/ 4 Channels at 3.125 Gbps • Longer Lines up to 1 M long • Narrower lines with higher conductor loss
Lossy transmission line Model • Characterisitic impedance Zo = √(R+JwL)/(G+JwC) • R and G are not negligible
What is attenuation (loss)? • The Voltage of a signal drops exponentially as the energy is absorbed in the dielectric medium, dissipated as conductor loss and radiated γ=α+ iβ Where α is the attenuation co-efficient and β is the phase related co-efficient 20 Log Vout / Vin = Loss in dB
Dielectric loss αDieletric(in dB) approx =2.3 *f(In Ghz) *df* √Dk
Conductor loss • Wider lines are less lossier due to reduced skin effect • A lower loss product like IS620 allows the designer to use thinner lines. αConductor(in dB/inch) approx =36/(w(line width in mils)*Z0(impedance) )* √f(In Ghz)
Effect of Conductor Roughness Surface roughness difference between 1 and 5 Microns = Dielectric loss tangent of 0.0028 –approx - 28-30 % of the dielectric loss
FR406 and IS415 are best in class - Loss close to Getek type products • PCL 370 HR is the highest loss product in this category
Material Challenges • Line Lengths and widths dictate the use of materials • More & More Standard materials will be used • Focus on equalization technologies • Key factors will be the ability to predict accurately P.U.L characterisitcs • While Dielectric losses dominate at higher speeds • Copper losses are not insignificant- Focus on Lower tooth profile
Isola Roadmap High Speed/High Frequency • Enabling High Speed Digital Speeds beyond 10 Gbps • Low Dk / Df Solutions with Conventional Process Friendly Technologies • Flat Df Response vs. Frequency for Higher Signal Integrity
Selection –High speed products • Key design factors in selecting products for very high speed applications • Data rates • Higher data rates require the use of Lower DF products • Faster Rise times • Lower DF • Higher Frequency range or bandwidth • Stable Dissipation factor over frequency and lower DF • Thinner packages • Narrower Lines- Lower DK and Lower Dissipation factor • Large Backplanes • Longer lines- Lower dissipation factors • Error correction- Predictable PUL properties • Equalization- • Pre emphasis • Reliability • Higher CAF, Thermal Cycling and Lead free assembly compatibility • Cost • Extendibility and scalability • Lower dissipation factor
Overview Lead free assembly • Overview Thermal Analysis • Thermal Resistance • Thermal Cycling Resistance • Isola Lead free product offering • Product selection for Lead free assembly
Overview • Restriction of Hazardous Substances • Legislation bans the following Six substances for shipment to EU countries – effective July 1 -2006 • Lead • Mercury • Hexavalent Chromium( Cr6+) • Polybrominated biphenyl • Polybrominated diphenyl ether • Cadmium • High End Networking companies exempt Max Conc. By Wt. < 0.1 % Max Conc. By Wt.< 0.01 %
Liquidus and Reflow Temperatures of Candidate Lead-Free Solder alloys for Replacing Eutectic Tin-Lead Solder Patented compositions; may require licensing or royalty agreements before use. **For more information see: Phase Diagrams & Computational Thermodynamics, Metallurgy Division of Materials Science and Engineering Laboratory, NIST. Source : NIST Website
Candidate Alloys for Replacing Lead-Alloy Solders Criteria for Down-Selection of Alloys Source : NIST Website
Thermal Resistance Drivers - Lead Free • Legislation driven < 1000 PPM of lead. • Lead Free Solders • Ternary alloys of Tin/Silver /Copper • Average reflow temperature 20-40 Deg C higher
Lead Free Laminate Attributes Lead Free ~Reflow Sn/Pb37 Reflow
Overview DSC / TMA / DMA /TGA • Isola ASL equipment • Dual cell DSC with autosampler • Dual Cell DSC • Pressurized DSC/Dual cell DSC with autosampler • TMA • TGA • DMA • Test Method • DSC • IPC-TM-650 2.4.25 Glass Transition and Cure Factor by DSC • TMA • IPC-TN-650 2.4.24 Glass Transition and Z-axis Thermal Expansion by TMA
Principle of Operation DSC: Differential Scanning Calorimetry Definitions • DSC measures the temperatures and heat flows associated with transitions in materials as a function of time and temperature in a controlled atmosphere. • These measurements provide quantitative and qualitative information about physical and chemical changes that involve endothermic and exothermic processes, or changes in heat capacity. • A DSC measures the heat into or out of a sample relative to a reference while heating the sample and reference with a linear temperature ramp. • Endothermic: Heat flows into the sample. • Exothermic: Heat flows out of the sample. • What is happening to the sample? • As the sample is heated, it absorbs energy in order to change the temperature of the sample • Energy units (W/g) Watts per gram of sample.
Glass Transition • A sample goes through the Glass Transition when the amorphous or not crosslinked areas change to (or from) a viscous or rubbery condition to (or from) a hard and relatively brittle condition • This is a fully reversible change • The glass transition takes place over a temperature range. • The glass transition temperature (Tg) is a temperature chosen to represent the temperature range over which the glass transition takes place. • NOTE: FIRST AND SECOND RUNS ARE DONE ON THE SAME PIECE OF SAMPLE • Delta Tg = Tg(run 2) - Tg(run 1) • What does a Delta Tg tell us? • Degree of Cure of the Laminate or Printed Wiring Board • Printed Wiring Board • All parts are cured equally
Selection of TG – First derivative Selection of TG – Half height -Isola DSC:Interpretation Selection of Tg - Inflection
TMA – Thermo Mechanical Analysis • TMA measures linear or volumetric changes in the dimensions of a sample as a function of time, temperature, and force in a controlled environment. • As the sample is heated, the material expands according to it’s Coefficient of Thermal Expansion (CTE) • Upon reaching its decomposition temperature (Td) delamination occurs • TMA: Measurements • Glass Transition Temperature (Tg) • Temperature of Decomposition (Td) • Time to Decomposition at 260C (T-260) • Time to Decomposition at 288C (T-288) • Coefficient of Thermal Expansion (CTE) • X, Y & Z Axis • Below Tg, Above Tg & Overall (20 - 288C) • Tg measurement • Materials exhibit a dramatic increase in CTE as it goes through the Tg region. • Measurement of the onset of the change determines the Tg • Temperature at which delamination of the sample occurs • Analysis can be obtained from 2nd scan Tg • Decomposition temperature • Measurement of onset of the dramatic change in probe position determines the Td • Similar onset analysis to T-260 T-288
TMA : Typical 1 St Run Chart TMA : Typical 2nd Run chart TMA
TMA: T-260 & T-288 Typical TMA Decomp Curves • Sample time at temperature before delamination occurs • Typical temperatures are 260C and 288C • Sample is heated at 100C/min to the desired temperature and quickly equilibrated • Sample is then held isothermally at the desired temperature until delamination occurs • T-260(288) = Time(delam) - Time(temp equilib) • TMA T-260 T-288 Method variations • Other laboratories heat sample at 10C/min • Side by side testing of 100C/min v 10C/min shows no measurable difference between the two methods
TGA Thermogravimetrical Analysis TGA Typical Curve • TGA measures the amount and rate of change in the weight of a material as a function of temperature or time in a controlled atmosphere. • Instrument made up of extremely sensitive balance within a controlled atmosphere • TGA: What is happening to the sample? • As the sample is heated, volatiles escape causing a loss of weight in the sample. • Upon decomposition, a dramatic weight change occurs. • TGA Measurements • Temperature at which x percent of weight is lost • Decomposition Temperature (Td)
DMA-Dynamic Mechanical Analysis • The periodic application of stress and strain to the material as the temperature is varied. • Measurement of the modulii of the material provides important physical information for the material as well as the Tg • Storage modulus: Measurement of the materials ability to store energy • Loss modulus: Measurement of the materials ability to dissipate energy • Tan Delta: Ratio of the storage modulus to the loss modulus • What is happening when the sample is being heated? • While the sample is being heated, it is physically displaced from parallel by a set force, to a set amplitude at a set frequency • The instrument measures the samples resistance to displacement and its ability to return to its original position. • These properties change as the temperature of the sample is changed • Sample becomes more elastic as it goes through the glass transition range • If cross-linking is occurring during the temperature increase, the sample becomes more rigid. • Measurements • Glass Transition Temperature (Tg) • Delta Tg • Modulus information • Two most common methods for selecting the glass transition temperature • Onset of the Storage Modulus • Peak of the Tan Delta
Typical DMA curve Broad Transition Increasing Cure Multiple Transitions DMA: Transitions
Thermal Resistance- Drivers • Drivers • Process conditions • Lead Free • OEM reliability requirements. • Failure mechanism - Matrix Decomposition and De-lamination
Thermal Resistance - Laminate factors • Laminate factors • Td- Decomposition temperature of laminate measured by weight loss by TGA. Function of Resin Chemistry • T-260,T-288 - Resistance to De-lamination at elevated temperatures. This follows a Power law. Function of Resin Chemistry and board design. • Tg - Marginal effect
Thermal Cycling Resistance-Drivers • Drivers • OEM reliability requirements due to harsh service conditions • Failure mechanism - Mainly metal Fatigue