Laser-Assisted Microtechnology

1. Introduction.- 1.1 Laser-Assisted Thin-Film Micromachining.- 1.2 Laser-Assisted Microprocessing and Modification of Materials.- 1.3 Laser Micropatterning.- 1.4 Pulsed Laser-Plasma Deposition of Thin Films.- 2. Laser-Based Equipment for Microtechnology.- 2.1 Principal Design of Laser-Based Microtechnological Equipment.- 2.2 Lasers Used in Microtechnological Systems.- 2.2.1 Lasers for Thin-Film Machining.- 2.2.2 Lasers for Microwelding and Microshaping.- 2.2.3 Lasers for Microlithography (Micropatterning).- 2.3 Optical Arrangement of the Energy Beam Line.- 2.3.1 The Beam-Contour (Focusing) Technique.- 2.3.2 The Projection Technique.- 2.3.3 The Contour-Projection Technique.- 2.3.4 The Active Projection Technique.- 2.3.5 Remarks on the Role of Light Coherence.- 2.4 Laser-Beam Trajectory Control.- 2.5 Optical Arrangement of the Visual Channel.- 3. Laser Micromachining of Thin Films.- 3.1 Physics of Laser-Induced Thin-Film Treatment.- 3.1.1 Film Heating Under the Action of Laser Radiation.- a) Absorption and Transformation of Beam Energy.- b) Film Temperature.- c) Heat Transfer to the Substrate.- d) Lateral Heat Transfer (in the Film).- e) Film-to-Substrate Adhesion.- f) Heating Non-Uniformity Along the Film Thickness.- g) Transverse Non-Uniformity of the Light-Beam Intensity Distribution.- h) Temperature Dependence of the Absorbance.- i) Temporal Variations of the Light Flux Density.- j) Cooling of Thin Films.- 3.1.2 Film Removal Under the Action of Laser Radiation.- a) Qualitative Discussion.- b) Theoretical Analysis of the Removal Process.- c) Phenomenological Two-Phase Removal Model.- d) Experimental Investigation of TAF Removal Process.- 3.2 Accuracy and Quality of Laser Thin-Film Micromachining.- 3.2.1 Thermal Distortions.- 3.2.2 Hydrodynamic Distortions.- 3.2.3 Changes of Substrate Properties During Laser Thin Film Treatment.- a) Sources of Cracks Formation.- b) Melting of the Substrate Surface Layers.- 3.3 Technological Processes in Laser Thin-Film Machining.- 3.3.1 Trimming of Thin Film Components.- a) Parameter Trimming and Repair of Hybrid Integrated Circuits.- b) Tuning of Quartz Piezoelements.- c) Functional Trimming of Thin Film Circuits.- 3.3.2 Shaping of Thin Films.- a) Photomask Repair.- b) Preparation of Passive Film Circuits.- c) Micromarking of Film Components.- 3.3.3 Information Recording by a Laser.- a) Digital Disc Information Recording.- b) Analog Data Recording.- 4. Local Laser-Induced Heat Treatment.- 4.1 Laser Heating of Absorbing Materials.- 4.1.1 Overall Characteristics of the Non-Demaging Heating.- 4.1.2 Excitation of Surface Electromagnetic Waves and Formation of Periodic Surface Structures.- 4.2 Applications of Laser Heating.- 4.2.1 Laser-Assisted Hardening.- 4.2.2 Local Laser Alloying.- 4.2.3 Local Laser-Induced Synthesis of Compounds.- 4.2.4 Laser Annealing of Ion-Implanted Semiconductors.- a) Characteristics of Laser Annealing.- b) Mechanisms of Laser Annealing.- c) Laser Annealing Capabilities as Compared with Other Methods.- 5. Laser Melting and Microwelding.- 5.1 Characteristics of the Laser-Induced Melting Process.- 5.2 Laser-Spot Microwelding.- 5.2.1 Wire Welding.- 5.2.2 Wire Welding to Contact Plates.- 5.2.3 Wire Welding to Thin Films.- 5.2.4 Welding of Thin Sheets.- 5.2.5 Laser Melt-Alloying of Metal-to-Semiconductor Contacts.- 5.3 Laser Seam-Welding.- 5.4 Factors Affecting the Laser-Welding Results.- 6. Laser Microshaping.- 6.1 Laser Hole-Drilling.- 6.1.1 The Process of Material Removal in Laser Hole-Drilling.- 6.1.2 Relationships for the Hole Formation in Absorbing Media.- 6.1.3 Accuracy and Reproducibility in Single Laser-Pulse Hole-Drilling.- a) Using a Pulse of Predetermined Shape and Structure.- b) Using the Projection Technique.- c) Processing in a Cylinidrical Light Tube.- d) Additional Means and Procedures Increasing the Treatment Precision.- e) Multiple-Pulse Hole Drilling.- 6.2 Laser-Driven Materials Separation.- 6.2.1 Laser Cutting.- 6.2.2 Laser Scribing.- 6.2.3 Laser Thermal Cleaving.- 7. Maskless Laser Micropatterning.- 7.1 Thermochemical Methods for Laser Patterning.- 7.1.1 Laser-Induced Oxidation of Thin Metal Films.- a) Oxidation Lithography. Accuracy and Resolution.- b) Application of Oxidation Lithography.- 7.1.2 Laser-Induced Reduction of Metal Oxides.- 7.1.3 Laser-Induced Thermal Decomposition of Organometallic Compounds.- a) Thermal Decomposition of Solid-Phase OMC.- b) Thermal Decomposition of Gas-Phase OMC.- 7.1.4 Laser-Induced Liquid-Phase Electrochemical Deposition and Etching.- a) Deposition.- b) Etching.- 7.1.5 Thermochemical Action of Laser Radiation on Polymer Materials.- 7.2 Photochemical Methods of Laser Patterning.- 7.2.1 Laser-Induced Photo-Decomposition of Gas-Phase Organometallic Compounds.- 7.2.2 Selective Laser-Assisted Photo-Etching.- 8. Pulsed Laser-Plasma Deposition of Thin Films, and Film Structures.- 8.1 Essentials of the Pulsed-Laser Plasma-Deposition Technique.- 8.2 Characteristics of the Pulsed-Laser Plasma-Deposition Process.- 8.2.1 Laser Radiation Interaction with the Target.- a) Free-Running Mode.- b) Q-Switched Mode.- 8.2.2 Inertial Expension of Laser-Ablation Products.- 8.2.3 Plasma-Substrate Interaction.- 8.2.4 Growth Mechanism and Film Properties.- 8.3 Typical Applications of the Pulsed-Laser Plasma-Deposition Method.- a) Deposition of Metals.- b) Synthesis of Polycomponent Thin Films.- c) Laser-Plasma Deposition of Multilayer Structures.- References.