High Versatility High Throughput Functional Testing Robert Polster, David Calhoun, Keren Bergman
Challenges of High-Throughput Functional Testing for Scalable Manufacturing
Numerous Functional Applications LIDAR: Transceiver: [MIT Christopher V. Poulton] Surface emitting Free space BioSensing: RF Electronics Switches: [KIT] Microfluidics [32 x 32 switch chip - AIST] High port numbers
Mechanical Alignment Challenges Emitted Field - Grating coupler Needed Mechanical Control Resolutions 10 µm [PI-Automated Fiber Alignment Engines ] 100 nm 0.5 Multi Chip Modules Complex Surface to place fiber and electric probes Fiber Array (c) TDK
Varieties of optical IO Grating Coupler Optical Coupler [Tianjin University] Edge Coupler Evanescent Coupler [AIST] [Caltech - Paul Barclay]
Step 1: Workstation Organization
Workstation Organization
Workstation Organization Key-Components: Optical and Electrical Switches
Key-Feature: Programmable Testing Workstation Organization
Top of Measurement Switch - Concept Equipment Rack: (c) Keysight (c) Anritsu (c)optotest (c) Tektronix (c) Siemon OUTPUT: Laser PPG Power Meter Oscilloscope Splitter In Splitter Out 1 Splitter Out 2 Fiber Array 1 Fiber Array 2 Fiber Array N Many Port All to All Optical Switching Unit INPUT: Laser PPG Power Meter Oscilloscope Splitter In Splitter Out 1 Splitter Out N Fiber Array 1 Fiber Array 2 X X X X Fiber Array N X Many Port Coupler - DUT - Wafer Prober: (c) TDK (c) MIT - Bryce Vickmark Packaged DUT: (c) Optilab
Top of Measurement Switch - Concept Less Alignments Parallel use of Equipment Switch Concept Pipelining of Tests Parallel testing of dice
Prober Hardware Hardware for concept validation: Costume designed fully automatic: Fiber Stages RF-Probe Stages Chip Stage Automated chip levelling Laser triangulation
Setups at LRL Manual Grating Coupling Manual Edge Coupling Automatic Grating Coupling 4 x Automated XYZ-Stages 1 x Pitch-Yaw-Roll Chip Stage Machine Vision Aided Calibration Automated Chip levelling Integrated equipment: Tunable Laser Powermeter Multimeter DC Voltage Source Automated System Prototype
Coupling Repeatability Coupling repeatability measured by uncoupling and recoupling the same structure Test Structure 90/10 Splitter: Standard Deviation: 0.133 db COUPLING VARIATIONS Coupling Variation [db] 0.3 0.2 0.1 0-0.1-0.2 1549 1549.5 1550 1550.5 1551 Wavelength [nm]
Prober Control Software Highly abstracted measurement control software to be used in arbitrary testbeds Prober Control s 3 pillars below the GUI Controlling Mechanics Library of Measurement Equipment Library of Measurement Functions performed using combinations of equipment i.a.: run_measurement_script() Connect_structure() get_o_spectrum() get_o_power()
Automatically Measured Loss Spectra Y-Splitter-Tree: 90/10-Splitter-Tree: meas. Power [db] Wavelength [nm]
Step 2: Standardization
Fundamental Test Sets Fundamental functional tests realized using test sets (see figure) High port count test sets allow: Connecting multiple devices Increases alignment precision Arrays > 100 fibers available N*127 um Further parallelization: Structures (and dices) in major grid, allows coupling several structures in parallel
64 Coupler 2 1 Current AIM Test Structures in Fabrication 3 5 6 4 7 8 9 10 11 12 13 Lipson s group No. Structure Name (1) Grating Array (2) ICT test structures (3) Ring Array (4) 8 Channel Demux (5) Switch Architecture (5) Structure for Quantum Key (6) WDM with Thermal Switch (7) WDM with 1x8 Thermal switch (8) High-Q Ring + custom heater (9) 1x8 Thermal Switch (10) Four channel WDM (11) High-Q Ring + Mod + Det (12) Four channel WDM + Det (13) 1x2 & 1x4 Thermal Switch (14) SiN Spiral + Mod
Semi-standardized package for functional testing 4-Channel WDM Transmitter Photonic subsystem test vehicle Fiber Grating Coupler 8-Channel WDM Filter V-groove fiber attach Fiber Grating Coupler 4x4 Mach Zehnder Switch Strain relief Fiber Grating Coupler Optically and electrically packaged silicon photonic subsystem SiP in socket
Switch Fabric Package and Test Automation 3D-printed sub-mount Switching State Calibration Device Characterization Customized PCB for edgecoupling Control Algorithm Optimization FPGA Control System LD array PD array 6-axis stage with ribbon-fiber holder Fiber-to-fiber loss Insertion loss test for all 256-case paths 21 19 17 15 13 1 2 3 4 5 6 7 8 9 Path category
Move to industry standard packages A standard for each application: Switches: e.g. CFP Transceivers and RF: Biosensors & Lidar : e.g. XFP COBO e.g. QFN
Package Tester Fast Package testing enabler: Development of test engine Connected to equipment rack Controlled by computer Development of daughter cards Optimized for each application