School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Course Tutor Dr R E Hurley Northern Ireland Semiconductor Research Centre School of Electrical & Electronic Engineering The Queen’s University of Belfast

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland 5. Processing in the real world. ‘Front-end’ and ‘Back-end’ a)Wafer Fab. Industrial b)Wafer Fab. Research Lab. A look at the equipment

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland The Chip-making Process

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Fabrication - a series of (?) loops, each puts a layer on the device. A loop comprises some or all of the major steps of photolithography, etch, strip, diffusion, ion implantation, deposition, and chemical mechanical planarization. Inspections and measurements performed to monitor the process and equipment at every stage. The ‘Wafer Fab’ (The Front-end processes)

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Supporting the entire process is a complex infrastructure of materials supply, waste treatment, support, logistics,and automation. Cleanest environment in the world - many times cleaner than the best hospital operating theatre. A state-of-the-art Fab, costing over $1 billion (+?), has a denser capital per square foot than any industry. The ‘Wafer Fab’ (The Front-end processes)

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland The “Back-end" is Test, Assembly and Packaging. Finished wafer is split up into individual die (chips) Assembled into packages which can be handled in the final applications. Full functional electrical test is performed at both wafer and package level to ensure outgoing quality. The ‘Wafer Fab’ (The Back-end processes)

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland A typical University Research ‘Fab Lab’.

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Main Fab Lab at QUB, Belfast Photolith ‘Clean’ measurements UHV Cluster tool Furnaces Cleaning & wet chemistry

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Entering and leaving the cleanroom

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland More about processes- Furnaces Bruce Furnace Bruce Industrial Inc. Tube 1: Diffusion. Tube 2: Annealing. Tube 3: oxidation. Tube 4: Special! Quartz tubes surrounded by heaters carefully designed to maintain even heating along length (regular calibration needed!)

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Tempress (QUB) More Furnaces Tube 1: Diffusion. Tube 2: Annealing. Tube 3: Oxidation. Tube 4: Smart-cut ASM (QUB)

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Rapid thermal anneal (RTA) Halogen lamps surround the wafer and deliver a heat-pulse to reform silicon lattice. The method controls the ‘thermal budget’. Dopant-diffusion controlled in depth. Nitrogen or vacuum environment. QUB systems made in University.

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland QUB system for high purity Si/SiGe epitaxy (B doping)

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Deposition- CVD Plasma Enhanced Chemical Vapor Deposition (PECVD) PlasmaLab Model DP800 SiO 2, SiO x N y, and Si 3 N 4 films.

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Deposition- CVD UHV for high purity (SiGe, copper) Cluster tool 3 chambers fed by ‘dealer arm’ with load-lock to load 150mm wafers Main central chamber

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Overhead gas-box Satellite chambers Deposition- CVD UHV for high purity (SiGe, copper)

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Gas-box fittings for UHV CVD system

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Planar Etch II (PE2) is a parallel-plate plasma etcher. O 2 used to ash organic contaminants.(e.g. remove hardened photoresist For SU-8 5: 200 W, 10 sccm O 2 flow : 300 nm/min) Processes – Plasma Etching

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Reactive Ion Etcher Anelva RIE DEM-451 Anelva Corporation STS Multiplex ICP Etch STS Processes – Dry Reactive Etching

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Trion RIE/ICP - (Trion Technology Minilock Phantom III RIE/ICP) Processes - Etching Inductively coupled plasma (ICP) RF → lower pressure, higher etch-rate, higher anisotropy (straighter sided trenches)

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Clean Oven Model: Ultra-Clean 100 (3497M-3) Manufacturer: Lab-Line Instruments Fisher Isotemp Vacuum Oven Model 281 Max temperature 300 C Minimum Pressure -92 kPa Baking and curing processes need ovens Photoresist, dehydration, spin-on-glass C max, with C uniformity

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Cleaning station with spin-dry and bonder QUB Ultrasonics Wafer bonder Spin-dryer

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Spin-dryer (close-up)

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Wet chemical bench Perspex cover Fume extraction Acids! HF, nitric etc.

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Ellipsometer Gaertner Scientific Corporation Model No AK Thickness and index of refraction for thin dielectric films Film thickness measurement

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland HP4156A Precision Semiconductor Parameter Analyzer Four probes that can serve as voltage sources, current sources, voltage monitors, and current monitors. I-V curve of a simple two terminal device, I d -V ds -V g graphs for MOSFETs, switching characteristics of logical gates, etc. Metrology (measurements)

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Film thickness from 100 to 500,000 Å A diffraction-grating based spectrometer measuring reflectance of films from 370 to 800nm wavelengths. Extrapolates thickness using known refractive index for film material and silicon substrate. Nanospec AFT Model 210 Film thickness measurement

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Profilometer Model: Alpha-step 200 Manufacturer: Tencor Instruments Vertical ranges of: 1000Å, 2500Å, 5000Å, 10kÅ, 25kÅ, 50kÅ, 100kÅ, 250k, 500kÅ and 1000kÅ Leveling (Auto, Manual) Scan Length: 3mm (Manual mode), 2.5mm (Automatic) Resolution: 50 Å Alpha-Step Step-height on thin films

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Leica DM LB 100T A good selection of microscopes is important!

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland OPEN-DAY at NISRC, QUB, Belfast Students from schools visit the microelectronics group

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland Training in ‘robing’

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland A competition to find the fastest dresser! ??

School of Electrical and Electronic Engineering Queen’s University Belfast, N.Ireland With a prize for the winner!!