Semilab Technologies for 450mm Wafer Metrology

Transcription

1 Semilab Technologies for 450mm Wafer Metrology Tibor Pavelka Semilab Semiconductor Physics Laboratory Co. Ltd. Sem iconductorphysics Laboratory Co.Ltd. 1

2 Outline Short introduction to Semilab Technologies with potential for 450mm Non-destructive, capable of inline process control Contamination monitoring Epi layer monitoring Implant monitoring Dielectric characterization Metal layer characterization Characterization of etched structures Destructive / analytical tools Sem iconductorphysics Laboratory Co.Ltd. 2

3 Short Introduction Semilab Facts Main activity: Development, manufacturing and marketing of metrology equipment for the semiconductor and photovoltaic industries. Revenue exceeds $ 50 million (2008) Employees: 258 worldwide, 152 in Hungary Laboratory, office and manufacturing space: 11,000 m 2, about 3,000 m 2 in the US 76 physicists employed (43 in Hungary) 25 employees holding a Ph. D. in physics (5 in Hungary) Installed base: more than 2,300 units Patents: wholly owned 90, applications 8, lincensed 41 Listed as 35 th among the 50 fastest growing Central- East European technology companies (Deloitte) in 2008 Sem iconductorphysics Laboratory Co.Ltd. 3

4 History of Semilab Sem iconductorphysics Laboratory Co.Ltd. 4

5 History of the Semilab Group Sem iconductorphysics Laboratory Co.Ltd. 5

6 Semilab around the World Sem iconductorphysics Laboratory Co.Ltd. 6

7 Semilab People France 6% Semilab Worldwide USA 23% Qualifications Other 28% PhD 10% PhD students 3% Hungary 59% Japan 5% China 6% Singapore Germany 1% UK Others 1% Administrative 11% University/ College without PhD 59% Manufacturing & Assembly 24% Physicists 29% Engineers 35% Tasks Sem iconductorphysics Laboratory Co.Ltd. 7

8 Semilab in European Cooperations Successful participation in the SEA-NET project MetalMap: lifetime monitoring and metal contamination measurement on bare wafers Lead It: contactless sheet resistance measurement via junction photo-voltage technique Member of the EEMI450 Participant in other projects under development or evaluation Becoming an active player in European cooperation Sem iconductorphysics Laboratory Co.Ltd. 8

9 Contamination Monitoring I. Lifetime Measurement (μ-pcd)( Minority charge carrier lifetime: effective parameter to characterize the purity of semiconductor material μ-pcd method: simple, robust, powerful technique for lifetime monitoring Available in WT wafer testers (from bench-top platform to fully automated 300mm tool) Possible application in 450mm lines Excitation (generation of excess charge carriers) Redistribution of carriers τ diff diffusion of carriers to the surface τ bulk bulk recombination meas τ surface surface recombination = + τ τ τ + bulk 2 d 2 π D d 2 S τ meas : measured lifetime τ surface : surface recombination lifetime τ diff : characteristic time for diffusion to the surface from the bulk τ bulk : bulk recombination lifetime τ τ diff surf = = n,p diff τ Thermal equilibrium surf D: diffusion constant of minority carriers d: wafer thickness S: Surface recombination velocity Sem iconductorphysics Laboratory Co.Ltd. 9

10 Contamination Monitoring II. SPV Diffusion Length Measurement Diffusion length: key parameter for semiconductor characterization, especially for metal contamination monitoring Fast, non-contact, non-destructive whole wafer mapping Measurement principle: Excess charge carrier pairs are generated by laser pulse surface photovoltage appears V SPV ~Δn, V SPV : measured surface photovoltage, Δn: number of excess charge carriers Measurement with different lasers The following equation is fulfilled: Φ V SPV 1 = C L + α Φ: photon flux density L: diffusion lengtjh 1/α: penetration depth Silicon wafer Integrated SPV Measuring Unit Periodic excitation SPV Plot Lasers V SPV Φ ( 1 ) () 1 V SPV SPV electronics Lock-in detection Capacitive sensor Φ ( 2 ) ( 2) V SPV Computer L [µm] 1/α (1) 1/α (2) 1/ α [µm] Sem iconductorphysics Laboratory Co.Ltd. 10

11 Epi Layer Monitoring I. Dopant and Resistivity Profiling by Airgap CV EPIMET real-time, non-contact, nondestructive production line control for epi processes No need for monitor wafers Pre-treatment is integrated Resistivity and dopant profile plotting Wafer mapping Excellent repeatability (<1%) in the range of Ωcm LED bellows air filter material guard electrode air bearing silicon wafer wafer vacuum chuck Sem iconductorphysics Laboratory Co.Ltd. 11

12 Epi Layer Monitoring II. Surface Charge Profiling Measurement of n/p, n/n, p/p, p/n epi even over buried layers Measures Doping concentration Resistivity Depletion layer width Surface recombination lifetime Conductivity type Based on high frequency AC surface photo-voltage hν ~~~~ Illumination Dark R e R h e h hν W d Bulk p-type δv s W d High frequency surface photo-voltage Low intensity: δ V s < 0.05 kt/q Wavelength < 400 nm δ V s ~W d ~1/C sc W d-inv = ƒ(nsc) Sem iconductorphysics Laboratory Co.Ltd. 12

13 Epi Layer Monitoring III. Fast Non-penetrating Elastic Metal probe for rapid monitoring of epi layers EM-probe: nondestructive probe for capacitance measurements and IV-profiling Small tip diameter to enable sheet resistance profiling CV profiling Gate Sem iconductorphysics Laboratory Co.Ltd. 13

14 Implant Monitoring I. Carrier Illumination In-line, non-contact, pre-anneal monitoring of Implant Dose PAI depth Junction depth BX-3000 Carrier Illumination Technology Generation laser creates excess carriers Excess carriers gradient forms index of refraction gradient Probe laser reads out index of refraction to determine junction properties Probe laser (980 nm IR) Detector Cognex PatMax Vision system Generation laser (830 nm red) Beam splitter Objective lens Deep BX-10 Xj measured contour Shallow Sem iconductorphysics Laboratory Co.Ltd. 14

15 Implant Monitoring II. Junction Control the implant and anneal by measuring sheet resistance (R s ) of the implanted layer after anneal LED generates charge carriers which spread laterally Spreading is detected capacitively, R s is calculated Non-contact, nondestructive Fast, high resolution mapping Good repeatability Good correlation with conventional techniques Works from USJs to deep implants Photo-Voltage Sheet r. 4pp [Ohm/sq.] LED Pickup electrodes Junction Si substrate JPV Sheet resistance [Ohm/sq.] Vendor 1 Vendor 2 Sem iconductorphysics Laboratory Co.Ltd. 15

16 Dielectric Characterization I. Spectroscopic Ellipsometry GES5E: R&D Spectroscopic Ellipsometer to meet requirements of emerging technologies / materials Measures complex reflectance ratio ρ = r r p s iδ = tan Ψe = f tan Ψ, cos Δ ( n, k, T ) Parameters: Spectral range: from 190 nm to 2.5 µm high resolution and/or fast measurement mode Unique combination with further techniques: Grazing X-Ray Reflectance FT Infra-Red Spectroscopic Ellipsometry up to 33 µm Adsorption, EPA: Ellipsometric Porosimeter (EP) at atmospheric pressure tan Ψ cos Δ Wavelength Sem iconductorphysics Laboratory Co.Ltd. 16

17 Dielectric Characterization II. Non-Contact MOS CV (VQ) for SiO 2 and High-κ Non-destructive measurement technique to replace traditional C-V measurements for qualifying oxide or other dielectric along with interface properties in silicon wafers Measured parameters T ox : Electrical oxide thickness V fb : Flatband voltage D it : Interface state density Q m : Mobile charge V ox : Oxide voltage Q eff : Effective charge E tunnel : Tunneling electric field V s : Surface potential V surf : Surface voltage V tunnel : Tunnel voltage Hight throughput: complete analysis in 15 minutes VQ curve Corona discharge Illumination Kelvin Probe T ox map Sem iconductorphysics Laboratory Co.Ltd. 17

18 Dielectric Characterization III. Near Field Scanning Microwave Microscope for Low-κ Non-contact microwave technique to measure the dielectric constant of low-k materials on production wafers Potential unique application: sidewall damage monitoring Near field antenna (10μm tip size << wavelength) at 100nm distance from the sample Resonant frequency depends on sample properties With suitable calibration, from resonant frequency measurements, κ-value can be determined Sem iconductorphysics Laboratory Co.Ltd. 18

19 Low-κ and Metal Layer Characterization Surface Acoustic Wave Non-contact, nondestructive tool to obtain Layer thickness Bilayer thickness Material properties (resistivity, grain size) Laser excitation generates acoustic waves which propagate Propagation is monitored, waveform and spectrum is analyzed 1. Dark signal before wave excitation. 2. Wave excitation with striped pattern. 3. Wave motion and diffraction of probe beam to detector. Waveform and frequency spectrum. Sem iconductorphysics Laboratory Co.Ltd. 19

20 Characterization of 3D Etched Structures and Threnches Model Based Infrared Reflectometry Thickness, depth, CD, and composition can be determined Sample is illuminated by IR light Reflections & absorptions from trenches and films determine shape of reflectance spectrum Spectrum is analyzed with a model of the sample structure, and parameters are determined by fitting the model spectrum Infrared Light microns wavelength Reflectance 45 Reflectance Spectrum Absorption bands Layers of Interest Interference fringes Wavenumber (cm -1 ) Detector Exp. Data Model Fit Sem iconductorphysics Laboratory Co.Ltd. 20

21 Destructive / Analytical Tools Potential for 450 mm DLTS: Deep Level Transient Spectroscopy for contamination analysis LST: Light Scattering Tomography for bulk microdefect characterization SIRM: Scanning Infrared Microscopy for bulk defect characterization SRP: Sheet Resistance Profiling Sem iconductorphysics Laboratory Co.Ltd. 21