RFIC Design ELEN 351 Lecture 3 RFIC Layout and Modeling Techniques Instructor Dr Allen Sweet Copy Right 2003 ELEN 351 1 General Layout Rules All Dimensions are in microns Cap is in pF or fF Ind is in nH Res is in Ohms Use 5 microns as the finest grid on the CAD Layout Tools ALL metal lines are TRANSMISSION LINES and must be modeled as such Layout should keep all parasitic elements to a minimum value for best performance Layout should keep chip area to a minimum for lowest cost Copy Right 2003 ELEN 351 2 GaAs HBT Virtual Foundry Design Rules Layers and Structures Electrical Models Current Limits on Metals Layout Design Rules Design example Copy Right 2003 ELEN 351 3 HBT EPI Structure Copy Right 2003 ELEN 351 4 HBT Physical Structure Copy Right 2003 ELEN 351 5 Cross Section of Metal and Dielectric Layers Copy Right 2003 ELEN 351 6 Layer Definition LAYER NUMBER 6 9 10 12 13 14 16 18 63 NAME CM TFR M1 NV M2 PV SPV SV TXT COLOR WHITE PURPLE GREEN BLUE RED AQUA YELLOW RED WHITE DESCRIPTION COLLECTOR METAL THIN FILM RESISTOR FIRST METAL NITRIDE VIA SECOND METAL POLYIMIDE VIA SCRATCH PROTECT VIA SUBSTRATE VIA TEXT Copy Right 2003 ELEN 351 7 Layer Thickness LAYER THICKNESS UNITS CM 1 MICRONS TFR 0 3 MICRONS M1 2 MICRONS NITRIDE 2000 ANGSTR POLY 2 MICRONS SCRATCH PROTECT 4 MICRONS GaAs SUBSTRATE 100 MICRONS Copy Right 2003 ELEN 351 8 Layer Resistance LAYER RESISTANCE IN OHMS PER SQUARE CM 15 TFR 50 M1 0 02 M2 0 01 Copy Right 2003 ELEN 351 9 Maximum Current Density LAYER MAX CURRENT UNITS CM 4 mA per micron M1 4 mA per micron M2 8 mA per micron TFR 1 mA per micron HBT Cell 10 mA M1 to M2 VIA 3 mA per square micron Copy Right 2003 ELEN 351 10 Minimum Line Widths LAYER CM TFR M1 NV M2 PV SPV SV MINIMUM WIDTH 4 4 4 2 5 2 50 30 in diameter UNITS microns microns microns microns microns microns microns microns NOTE NO DONUTS ARE ALLOWED ON ANY METAL LAYER Copy Right 2003 ELEN 351 11 Minimum Same Layer Line Spacing LAYER CM TFR M1 NV M2 PV SPV SV MIN SPACING 2 3 4 4 4 4 40 200 edge to edge Copy Right 2003 ELEN 351 UNITS microns microns microns microns microns microns microns microns 12 Cross Section of a Microstrip Transmission Line Copy Right 2003 ELEN 351 13 Transmission Line M1 or M2 W Length L M1 OR M2 Copy Right 2003 ELEN 351 14 Transmission Line Cross Section Copy Right 2003 ELEN 351 15 ADS Model for a Transmission Line Copy Right 2003 ELEN 351 16 Coupled Transmission Lines Spacing S Width W Length L M1 or M2 M2 or M1 Copy Right 2003 ELEN 351 17 ADS Model for Coupled Transmission Lines Copy Right 2003 ELEN 351 18 Thin Film Resistor TFR M1 R L W 50 Ohms W M1 M1 TFR 2 microns L Copy Right 2003 ELEN 351 2 microns 19 Resistor Cross Section Copy Right 2003 ELEN 351 20 ADS Model for Thin Film Resistors Copy Right 2003 ELEN 351 21 M1 to M2 VIA M2 M1 PV NV M2 M1 PV NV Layer enclosure Is 5 micron Copy Right 2003 ELEN 351 22 M1 to M2 VIA Cross Section Copy Right 2003 ELEN 351 23 MIM Capacitor M1 PV M2 Normal Range Is 05 pF to 10 pF C 300 fF per Square micron M1 PV M2 Layer enclosure Is 50 micron Copy Right 2003 ELEN 351 24 Capacitor Cross Section Copy Right 2003 ELEN 351 25 ADS Model for the MIM Capacitor M1 M2 Copy Right 2003 ELEN 351 26 Substrate Via CM M1 PV NV M2 SV SV Layer enclosure Is 50 micron Copy Right 2003 ELEN 351 CM M1 PV NV M2 27 Substrate VIA Cross Section Copy Right 2003 ELEN 351 28 Bond Pad CM M1 PV NV M2 SPV 100 x 100 microns CM M1 PV NV M2 SPV Layer enclosure Is 50 micron Copy Right 2003 ELEN 351 29 Bond Pad Cross Section Copy Right 2003 ELEN 351 30 Wafer Probe Pad Pairs 150 microns Copy Right 2003 ELEN 351 31 M1 M2 Crossover M2 C 15 fF per Square micron M1 Copy Right 2003 ELEN 351 32 ADS Model for the M1 to M2 Crossover Copy Right 2003 ELEN 351 33 TFR M2 Crossover C 15 fF per Square micron M2 M1 TFR Copy Right 2003 ELEN 351 M1 34 ADS Model for the TFR to M2 Crossover Copy Right 2003 ELEN 351 35 Spiral Inductor M1 M2 L2 Normal Range Is 1 nH to 5 nH L1 N 1 25 W S Copy Right 2003 ELEN 351 36 ADS Spiral Inductor Model Copy Right 2003 ELEN 351 37 LAYOUT PARASITIC ELEMENTS THAT MUST BE INCLUDED BELOW 5 GHz Copy Right 2003 ELEN 351 38 ADDITIONAL LAYOUT PARASITIC ELEMENTS ABOVE 5 GHz Copy Right 2003 ELEN 351 39 Single Finger HBT Transistor Dummy Cell Layout M1 M1 M1 Emitter Dimensions 2 microns X 12 microns 25 microns All contacts are M1 No metal may Cross over an HBT Cell Contacts come From the side M1 Copy Right 2003 ELEN 351 19 microns 40 Single Emitter Finger HBT Transistor Gummel Poon Model Copy Right 2003 ELEN 351 41 3 Emitter finger A 3 HBT Transistor M1 M2 M1 to M2 VIA Copy Right 2003 ELEN 351 42 Details of the Three HBT Cell Interconnections Cell 1 Cell 2 Cell 3 Note Butt Collectors together Copy Right 2003 ELEN 351 43 Homework 2 Amplifier Layout HBT Transistor is A 3 Copy Right 2003 ELEN 351 44 Blow up of Amplifier Circuit Elements M1 to M2 VIAs R1 Output Input HBT A 3 R2 Ground Copy Right 2003 ELEN 351 45 Modified Amplifier Schematic Including All Parasitic Elements Copy Right 2003 ELEN 351 46 Blow up of Layout Electrical Model Resistor R1 PAD PAD Base Line Collector Line Resistor R2 SVIA Copy Right 2003 ELEN 351 47 ADS Simulations including Layout Parasitic Elements Copy Right 2003 ELEN 351 48