Optimization of Ammonia-Peroxide Water Mixture (APM) for High Volume Manufacturing through Surface Chemical Investigations Item Type text; Electronic Dissertation Authors Siddiqui, Shariq Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 07/10/2021 08:52:30 Link to Item http://hdl.handle.net/10150/201511 OPTIMIZATION OF AMMONIA-PEROXIDE WATER MIXTURE (APM) FOR HIGH VOLUME MANUFACTURING THROUGH SURFACE CHEMICAL INVESTIGATIONS Shariq Siddiqui ___________________________________________ A Dissertation Submitted to the Faculty of the DEPARTMENT OF MATERIALS SCIENCE AND ENGINEERING In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College THE UNIVERSITY OF ARIZONA 2 0 11 2 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of Dissertation Committee, we certify that we have read the dissertation prepared by Shariq Siddiqui entitled Optimization of Ammonia- Peroxide Water Mixture (APM) for High Volume Manufacturing through Surface Chemical Investigations and recommend that it be accepted as fulfilling the dissertation requirement for the degree of Doctor of Philosophy. _____________________________________________________ Date: 5/13/11 Srini Raghavan _____________________________________________________Date: 5/13/11 Supapan Seraphin _____________________________________________________Date: 5/13/11 Jinhong Zhang _____________________________________________________Date: 5/13/11 Manish Keswani Final approval and acceptance of this dissertation is contingent upon the candidate’s submission of the final copies of the dissertation to the Graduate College. I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requirement. _____________________________________________________ Date: 5/13/11 Dissertation Director: Srini Raghavan 3 STATEMENT BY AUTHOR The dissertation has been submitted in partial fulfillment of requirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the library. Brief quotations from this dissertation are allowable without special permission, provided that accurate acknowledgement of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his or her judgment the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author. SIGNED: Shariq Siddiqui 4 TABLE OF CONTENTS LIST OF FIGURES………………………………………..……………………………7 LIST OF TABLES………………………………………..………………………........10 ABSTRACT……………………………………………………………………...……..14 CHAPTER 1: INTRODUCTION………………………………………………………16 CHAPTER 2: LITERATURE REVIEW AND BACKGROUND…..........................24 2.1. Overview of Semiconductor Wafer Cleaning………………………………….24 2.2. Silicon Surface Wettability……………………………………………………….31 2.3 Particle-Wafer Interactions in Wet Cleaning Systems………………………...37 2.3.1 Van der Waals Forces………………………………………………….38 2.3.2. Electrical Double-Layer Interaction Forces………………………….47 2.4 Measurement of Interaction Forces……………………………………………. 53 2.5. Overview of Atomic Force Microscope (AFM)………………………..……….54 2.5.1 Principle of Force Measurements in Atomic Force Microscope…………............................................................................................56 2.6. Literature Review for Interaction Force Measurements using AFM………...58 2.7. Literature Review for the Stability of Ammonia-Peroxide Mixture (APM)…..64 CHAPTER 3: EXPERIMENTAL PROCEDURE AND METHODS………………..70 3.1. Materials …………………………………………………………………………..70 3.2. Silicon Surface and Tip Preparation……………………………………………70 3.3 Contact Angle Measurements.…………………………………………………..71 5 TABLE OF CONTENTS-CONTINUED 3.4. Surface Force Measurements……………..……………………………………72 3.5. Measurements of NH 4OH and H 2O2 concentrations using the Horiba SC-1 Composition Monitor………………………….……………………………………….75 3.5.1. Monitor Specification…….. …………………………………………...76 3.5.2. Data Acquisition………………………………………………………...77 3.5.3. Experimental Procedure for NH 4OH and H 2O2 Concentration Measurements.………………………………………...................................79 CHAPTER 4: RESULTS AND DISCUSSION………………………………….…...80 4.1. Interaction Force Measurements between Hydrophobic Si Surface and Si Tip using Atomic Force Microscopy……………………………………………………..80 4.1.1. Interaction Force Measurements between Si Surface and Si Tip in DI-water………………………………………………………………………...82 4.1.2. Interaction Force Measurements between Si Surfaces in NH 4OH:H 2O (1:100) Solution ….………………………………………….....84 4.1.3. Interaction Force Measurements between Si Surfaces in H 2O2:H 2O (1:100) Solution……………………………………………………………......86 4.1.3. Interaction Force Measurements between Si Surfaces in NH4OH:H 2O2:H 2O Solutions……………………………………………….....88 4.2. Analysis of Measured Adhesion Forces between Si Surfaces………………90 4.3. Comparison of Measured Repulsive Forces to Calculated Forces using Electrostatic Double Layer Theory…………………………………........................97 4.4. Comparison of Measured Adhesion Forces to Calculated Forces using JKR Adhesion Force Model……………………………………………………………….99 4.5. Brief Summary of Interaction Force Measurements………………..............104 6 TABLE OF CONTENTS-CONTINUED 4.6. Characterization of the Stability of APM Solutions using the Optical Concentration Monitor……………………………………………………………….105 4.6.1 Effect of Temperature on the Stability of APM Solution………......105 4.6.2. Effect of Dilution on the Stability of APM Solution………………...106 4.6.3. Effect of pH on the hydrogen peroxide decomposition…………...107 2+ 4.6.4. Effect of Iron (Fe ) Ions on H 2O2 Decomposition…………….......110 4.7. Kinetic Analysis of H2O2 Decomposition in APM Solutions …………..........111 4.8. Brief Summary of Stability of APM Solutions ….…………………………....119 CHAPTER 5: CONCLUSIONS AND FUTURE WORK ….………………………120 5.1. Interaction Force Measurements using Atomic Force Microscope………..120 5.2. Characterization of the Stability of APM Solutions using the Optical Concentration Monitor …………………………………..……………………….….121 5.3. Suggestions for Future Work..………………………..……………………….122 REFERENCES……………………………………………………………………….123 7 LIST OF FIGURES Figure 1.1: CMOS transistor pitch scaling trend vs. dates of introduction ……...17 Figure 2.1: Contaminated silicon wafer with different types of impurities………26 Figure 2.2: A schematic of typical wafer cleaning process in the front-end-of-line cleaning…………………………………………………………………………………27 Figure 2.3: A schematic of surface forces acting on three phase contact line of a liquid on the wafer surface……………………………………………………………31 Figure 2.4: Representation of water drop on (a) hydrophilic and (b) hydrophobic surfaces.………………………………………………………………………………..32 Figure 2.5: The interaction energy between two surfaces as a function of separation distance………………………………………………………………….. .37 Figure 2.6: Illustration of (a) same materials interacting in a liquid media and (b) two different materials interacting in a liquid media………………………………..41 Figure 2.7: A schematic representation of different potentials associated with a particle in aqueous solutions…………………………………………………………47 Figure 2.8: Zeta potential of particle contaminants as a function of pH…………51 Figure 2.9: Comparison of zeta potential of silicon dioxide (SiO 2) surfaces prepared using different treatment methods as a function of pH…………………52 Figure 2.10: (a) A schematic representation of interaction forces between the surface and the tip using AFM (b) An SEM image of a silicon tip………………..54 Figure 2.11: A schematic of AFM controller feedback loop to maintain constant deflection between the tip and the surface………………………………………….54 Figure 2.12: A schematic representation of different stages of force-distance curves…………………………………………………………………………………...57 Figure 2.13: (a) Normalized approach and (b) retract force curves between a silicon nitride tip and a silicon surface as a function of separation distance in DIW and HF solutions……………………………………………………………………….61 Figure 2.14: A schematic representation of iron-catalyzed decomposition of hydrogen peroxide in APM solutions………………………………………………...68 8 LIST OF FIGURES-CONTINUED Figure 3.1 : AFM image of silicon surface (2 x 2 µm) after etching in dilute HF solution...………………………………………………………………………………..71 Figure 3.2: Measured interaction forces between silica particle and silicon dioxide surface as a function of separation distance in 5 x 10 -4 NaOH solution…………74 Figure 3.3: A schematic representation of Horiba CS-100C monitor coupled with a solution bath interfaced with resistively heated jacked and temperature controller……………………………………..…………………………………………75 Figure 3.4: Measured and calculated (a) H 2O2 (b) NH 4OH concentrations in 1:1:5 APM solutions at different temperatures…………………………………………….77 Figure 3.5: A graphical representation of ammonium hydroxide, hydrogen peroxide, and water concentrations measured using the Horiba CS-100C concentration monitor…………………………………………………………………78 Figure 4.1: Water contact angle values for silicon surfaces treated with different solutions as a function of time………………………………………........................82