New Low Cost Surge Resistive Inks Michail Moroz Aziz Shaikh IMAPS - PowerPoint PPT Presentation

Ferro Electronic Material Systems New Low Cost Surge Resistive Inks Michail Moroz Aziz Shaikh IMAPS 2002 Denver, CO

Outline • Definition • Surge Protection Types • Lighting Surge Tests • Standard 85-series • Problems Caused by Pd Content Reduction • RE88-series Development Results • Summary Michail Moroz IMAPS 2002, 2 morozm@Ferro.com Denver, CO 2

Definition • Surges - large current or voltage peaks for short periods of time • Surge resistor - part of secondary surge protection from voltage/current pulses or main voltage overload • Surge protection circuits typical applications: � Dissipation of the secondary voltage surge � Sensing of changes in electrical current in circuits • Circuit design: � Usually a pair of matched resistors on a common single-in-line (SIL) substrate Michail Moroz IMAPS 2002, 3 morozm@Ferro.com Denver, CO

Types of Surge Protection • Primary surge protection: � Handles the high voltage transients � Exists where the telephone line enters the building � Dissipates very large amounts of power Secondary surge protection: • � Deals with the residual fault current passed from the primary protection � Is usually built into the equipment to be protected � Detects high voltages and passes the energy to ground before any damage is done Michail Moroz IMAPS 2002, 4 morozm@Ferro.com Denver, CO

Lighting Surge Tests Bellcore Spec. GR-1089: • � 10 x 1000 µ sec, 1kV, 50 pulses, 60 sec between pulses � 2 x 10 µ sec, 2.5kV, 20 pulses, 60 sec between pulses ITU-T K.20: • � 10 x 700 µ sec, 1.5kV, 20 pulses, 60 sec between pulses Ferro Internal Specs: • � Non-Destructive - 10 x 700 µ sec, 2.8kV, 10 pulses, 20 sec between pulses � Destructive - 10 x 700 µ sec starting at 2.8kV, 20 sec between pulses Michail Moroz IMAPS 2002, 5 morozm@Ferro.com Denver, CO

85-Series • Pd / Ag Ratio: 56 / 44 • Resistivity: 0.1 Ω / � ÷ 10 Ω / � • TCR: < ± 100 ppm • Drift After Lighting Surge: < 0.1% Michail Moroz IMAPS 2002, 6 morozm@Ferro.com Denver, CO

Problems Caused by Pd Content Reduction • High positive TCR • Undesirable ink rheology change (viscosity/slope balance) and resultant poor resistor print shape • Lower voltage performance: � Noticeable negative resistance drop after surge test � Much less voltage to failure • Much higher long-term resistance shift Michail Moroz IMAPS 2002, 7 morozm@Ferro.com Denver, CO

Low Cost RE88-series Development Results • Reduced Palladium content and inks cost by 30% • Optimized: � Inks rheology and printability � Resistivity vs. peak firing temperature � Hot/Cold TCR curve slope � Long-term stability � Resistance shift after lighting surges � Voltage to failure Michail Moroz IMAPS 2002, 8 morozm@Ferro.com Denver, CO

Resistivity & TCR vs. Pd/Ag Ratio Pd Content, %wt 55 45 40 30 25 20 15 10 0.8 900 TCR of Ag-Pd Alloys 800 0.7 4000 Resistivity, Ohm/Sq 3000 TCR, ppm 700 0.6 2000 TCR, ppm/°C 600 1000 0.5 0 500 0 0 0 0 0 5 0 0 0 0 0 0 1 2 3 4 5 5 6 7 8 9 0 1 0.4 Pd Content 400 0.3 300 0.2 200 Resistivity TCR 0.1 100 0 0 45 55 60 70 75 80 85 90 Ag Content, %wt Michail Moroz IMAPS 2002, 9 morozm@Ferro.com Denver, CO

R 1 /R 2 Ratio vs. Temperature 0.10 85 - 0.5 0.08 Standard Pd/Ag Ratio R 1 / R 2 Ratio Relative Change, % TCR = +- 100ppm 0.06 0.04 0.02 0.00 -0.02 -0.04 -0.06 -0.08 -0.10 25 35 45 55 65 75 85 95 105 115 125 Temperature, °C Michail Moroz IMAPS 2002, 10 morozm@Ferro.com Denver, CO

R 1 /R 2 Ratio vs. Temperature 0.10 RE88 - 0.5 0.08 R 1 /R 2 Ratio Relative Change, % Thrifted Resistors 0.06 TCR = + 400ppm 0.04 0.02 0.00 -0.02 -0.04 -0.06 -0.08 -0.10 25 35 45 55 65 75 85 95 105 115 125 Temperature, °C Michail Moroz IMAPS 2002, 11 morozm@Ferro.com Denver, CO

TCR vs. Temperature 450 Thrifted Resistors 440 212 Sq, 0.50 Ohm/Sq 430 420 Reference Point: 25C TCR, ppm 410 400 390 380 370 360 350 -55 -35 -15 0 45 65 85 105 125 Temperature, °C Michail Moroz IMAPS 2002, 12 morozm@Ferro.com Denver, CO

Viscosity to Slope Ratio Effect on Open Voltage to Failure 3400 Standard Vehicle Adjusted Vehicle 3300 Open Voltage to Failure, Volts 3200 3100 3000 2900 2800 2700 2600 2500 1841 1541 1430 1305 1271 1171 1159 1145 1107 1066 Viscosity to Slope Ratio, Absolute Value Michail Moroz IMAPS 2002, 13 morozm@Ferro.com Denver, CO

Squeegee Pressure Effect #1: Squeegee Pressure (SP) is Too Low # 2: Increased SP, but Thickness is not Uniform Yet # 3: Further Increased SP, Much More Uniform Resistor Shape #4: The Most Uniform Resistor Thickness, the Best Surge Performance Michail Moroz IMAPS 2002, 14 morozm@Ferro.com Denver, CO

SEM Images of Dried 20-mil Width Resistors Michail Moroz IMAPS 2002, 15 morozm@Ferro.com Denver, CO

Effect of Additive Content on Resistance Shift After Voltage Loading 1 RE88-series, 0.1 Ohm/Sq 0.8 RE88-series, 0.5 Ohm/Sq 0.6 Resistance Shift, % Optimum 0.4 Compositions 0.2 0 -0.2 -0.4 0 1 2 3 4 5 Additive Content, % Michail Moroz IMAPS 2002, 16 morozm@Ferro.com Denver, CO

R 1 /R 2 Ratio Change After Surge Test 30.0 1000 Vpk, 10 x 1000 microsec, 100 Pulses Ratio Change Distribution, % 25.0 RE88-0.5-2 +- 0.02%: 81% +- 0.03%: 92% 20.0 +- 0.05%: 96% 15.0 10.0 5.0 0.0 -0.10 -0.08 -0.06 -0.04 -0.02 0.00 0.02 0.04 0.06 0.08 0.10 Ratio Change, % Michail Moroz IMAPS 2002, 17 morozm@Ferro.com Denver, CO

Effect of Peak Firing Temperature on Resistance Shift After Surge Test 0.20 85-series, 0.8 Ohm/Sq RE88-series, 0.8 Ohm/Sq 0.15 RE88-series, 0.1 Ohm/Sq Resistivity Change, % 0.10 0.05 0.00 -0.05 -0.10 800 825 850 875 Peak Firing Temperature, °C Michail Moroz IMAPS 2002, 18 morozm@Ferro.com Denver, CO

Resistance Sensitivity to Peak Firing Temperature 50 85-series, 0.8 Ohm/Sq 45 RE88-series, 0.8 Ohm/Sq 40 RE88-series, 0.1 Ohm/Sq Resistivity Change, % 35 30 25 20 15 10 5 0 800 825 850 875 Peak Firing Temperature, °C Michail Moroz IMAPS 2002, 19 morozm@Ferro.com Denver, CO

Long-term Resistance Drift After Surge Test 0.20 85-0.5 RE88-0.5 0.15 Resistance Shift, % 0.10 0.05 0.00 -0.05 Non-Destructive Surge Test: -0.10 Pulse Type: 10/700 microsec No. of Pulses: 10 -0.15 Voltage: 2.8 KV -0.20 0 12 36 96 250 400 600 800 1000 Dwell Time at 150°C, Hours Michail Moroz IMAPS 2002, 20 morozm@Ferro.com Denver, CO

RE88-series Resistors Controllable Characteristics • Resistivity • TCR • Rheology: Up/Down curves slope • � R after refiring at 600 ° C & 850 ° C • � R after surge test • Voltage to failure Michail Moroz IMAPS 2002, 21 morozm@Ferro.com Denver, CO

Summary • New RE88-series thrifted surge resistors: � Reduced content of Palladium � Resistivity range: 0.1 Ω / � ÷ 1.0 Ω / � � TCR ≤ + 400 ppm � TCR deviation measured from -55 ° C to +125 ° C less than ± 30 ppm � R 1 :R 2 ratio matching similar as for standard resistors � Controlled performance � Similar surge protection and long-term reliability as standard 85-series resistors at a lower cost Michail Moroz IMAPS 2002, 22 morozm@Ferro.com Denver, CO