Defects Panel Discussion

Transcription

1 Defects Panel Discussion David Y. H. Pui Distinguished McKnight University Professor LM Fingerson/TSI Inc Chair in Mechanical Engineering Director of the Particle Technology Laboratory University of Minnesota

2 Issues in Defects Nanoparticle standards for inspection system calibration Characterization of nanoparticle contaminations AMC and Haze

3 NIST PSL Particle Standard: 60 and 100 nm

4 Nanometer Differential Mobility Analyzer (Nano-DMA)

5 Modal (Peak) Diameter and Expanded Uncertainty (95 % Confidence Interval) for Two New NIST SRMs 100 nm spheres along with 205 nm spheres Duke Scientific Co. Nominal 100 nm Polystyrene Spheres nm ± 1.1 nm 60 nm spheres with 200 nm length scale in bottom left of image JSR Co. Nominal 60 nm Polystyrene Spheres nm ± 0.61 nm

6 Issues with PSL Particle Standard Different light scattering than particles from processes Decomposition from exposure to deep ultra-violet (DUV) lights Deformation due to adhesion forces A 1.3 µm PSL sphere after adhering to a chromium surface for 24 hrs. From Dahneke, B. The influence of flattening on the adhesion of particles, J. Colloid Interface Sci., vol. 40(1), (1972).

7 Demand for Particle Standardization Calibration of surface inspection tools with particles of different materials Development of accurate size standards Providing samples for cleaning studies

8 SiO 2 Particles in Original Suspension

9 Generation of Monodisperse Aerosols Nanometer Differential Mobility Analyzer (Nano-DMA)

10 Tandem DMA (TDMA) Experimental Setup

11 40 nm Classification from Polysciences SiO 2 Original Distribution 1 st DMA 40 SEM Image of 40 nm SiO 2 2 nd DMA 40

12 Electrostatic Deposition Deposition chamber: a modified Standard Mechanical Interface (SMIF) pod Number of particles deposited N in = Q in C a t

13 Deposition Results on a Quartz Blank Deposition plan target 2000 per spot Inspection results using Lasertec M1350 at Intel, Santa Clara, CA. 60PSL 60nm PSL # ~ nm PSL # ~ nm PSL # ~ PSL 80Si02 60Si02 80nm PSL # ~ nm SiO2 # ~ nm SiO2 # ~ nm SiO2 # ~ nm SiO2 # ~ nm SiO2 # ~ 1980 The size of the four deposition spots is about 25 mm, very close to the target size of 25.4 mm. The deposition numbers computed from N in = Q in C a t are within the range of the target number ± 5%.

14 Scanner Counting Efficiencies capture efficiency (%) PSL on quartz PSL on chrome SiO2 on quartz SiO2 on chrome d p (nm)

15 Issues in Defects Nanoparticle standards for inspection system calibration Characterization of nanoparticle contaminations AMC and Haze

16 Mask Blank Effect of Secondary Packaging Witness Wafer Vibration Table With Secondary Packaging Without Secondary Packaging Controlled Vibration ISTA Procedure 1G at 1.15 G rms Vertical position Particle detection on 4 wafers Witness Wafer Scan (Deposited Particles) This work was done in cooperation with Entegris. Secondary packaging is helpful in reducing particle generation

17 Particle Source Identification ATOFMS Mask Scan Complex organic compound or mixture Possibly polymer Yook et al., IEEE Trans. Semi. Manu. 20(2): (2007). Contact points between the mask surface and pins Particles come mostly from contact points between mask surface and pins

18 Issues in Defects Nanoparticle standards for inspection system calibration Characterization of nanoparticle contaminations AMC and Haze

19 Haze Observed under Atmospheric and Vacuum Conditions 50nm SiO 2. Target deposition area: 1inch spot size at the center. Testing time: 2 min. (Atmospheric Pressure) 100 nm PSL particle. (Main Chamber p = 50 mtorr). Testing time: 1.5 hours

20 Airborne Molecular Contaminants (AMCs) Classification of AMCs Acids HF H 2 SO 4 HCl HNO 3 H 3 PO 4 HBr Condensable No Classes H 2 O 2 O 3 IPA Acetone Bases AMINE NH 3 NMP HMDS Dopants DOP DBP DEP Siloxanes BHT B 2 H 6 BF 3 AsH 3 TCEP TEP TPP SEMI Standard F21-95, 1996

21 High speed injection, 100 nm, 10 K/cm (Vacuum) Main Chamber p = 50 mtorr Flow rate = lpm Particle C = p/cc Testing time: 50 min Particle speed: 11.3 m/s Critical speed: m/s 100 nm particles mainly correspond to 20 pixel particles. About pixel particles are added.