Fiber-Optic Laser Wafer Edge Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for removing unwanted films, residues, and particles from the edges of semiconductor wafers are complex, costly, and inefficient, often requiring multiple chemicals and tools, and struggle to control edge exclusion width, leading to yield loss and environmental concerns.
Innovation Solution
A fiber-optic beam delivery system using laser radiation in the presence of air or gases to remove materials from all edges of silicon wafers, eliminating the need for solvents and corrosive chemicals, and incorporating a vacuum exhaust to prevent re-deposition of by-products, allowing precise control of the cleaning area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods (solvent spraying, wet chemical etching, mechanical grinding) are used to remove unwanted films from wafer edges, then material removal is achieved, but the process complexity increases, manufacturing cost increases, and edge exclusion width cannot be precisely controlled
Solution Approach 1:
The patent replaces mechanical grinding systems, chemical spraying systems, and wet etching systems with a laser-based system. The laser beam delivers energy directly to the wafer edge through optical fibers, enabling precise material removal without the complexity of mechanical or chemical process control systems. This substitution achieves superior edge exclusion width control while simplifying the overall device architecture.
Solution Approach 2:
The patent utilizes controllable laser parameters (power, pulse duration, wavelength, beam diameter) to precisely control the material removal process at the wafer edge. By adjusting these parameters, the system can achieve different edge exclusion widths and remove various types of unwanted materials (photoresist, metal, dielectric) with a single system, thereby improving manufacturing precision without increasing device complexity.
2Adaptability or versatility
If multiple chemicals and tools are used for edge cleaning, then various materials can be removed, but manufacturing cost increases and environmental harm increases
Solution Approach 1:
The laser-based system serves as a universal tool that can remove multiple types of unwanted materials (organic photoresist, inorganic metal films, dielectric materials) from wafer edges using a single platform. The system's versatility is achieved through programmable laser parameters and automated control, eliminating the need for multiple specialized chemical and mechanical tools, thereby reducing environmental harm while maintaining broad material removal capability.
Solution Approach 2:
The patent replaces harmful chemical solvents and wet etching processes with a clean laser-based energy delivery system. This substitution eliminates the generation of chemical waste, solvent emissions, and hazardous by-products, thereby significantly reducing environmental harm while maintaining the ability to remove diverse materials through controlled ablation and vaporization.
3Productivity
If solvent spraying or solvent cleaning is used for photoresist removal, then photoresist edge bead is removed, but the process requires multiple steps and manufacturing cost increases
Solution Approach 1:
The patent replaces multi-step solvent-based photoresist removal processes with a single-step laser-based ablation process. The laser beam, delivered through optical fibers, directly vaporizes photoresist material at the wafer edge, eliminating the need for solvent application, waiting periods, and multiple cleaning steps. This substitution dramatically improves productivity by reducing process time and simplifying the overall process flow.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively removes a wide variety of materials from all wafer edges in a single tool, reducing edge exclusion width, increasing die yield, and meeting future semiconductor manufacturing requirements by providing a precise, dry, and environmentally friendly process.
Implementation Method 1
directing laser radiation, in the presence of air or other fluids, to the top edge, top bevel, apex, bottom bevel, and bottom edge (hereinafter 'wafer edges') portions of the substrate
Implementation Method 2
By-products are removed by means of a vacuum exhaust
Data Source
AI summary
A method and apparatus for processing substrate edges is disclosed that overcomes the limitations of conventional edge processing methods and systems used in semiconductor manufacturing. The edge processing method and apparatus of this invention includes a laser and fiber-optic system to direct laser radiation onto a rotating substrate supported by a chuck. A laser beam is transmitted into a bundle of optical fibers, and the fibers accurately and precisely direct the beam to remove or transform organic or inorganic films, film stacks, residues, or particles, in atmosphere, from the top edge, top bevel, apex, bottom bevel, and bottom edge of the substrate in a single process step. Reaction by-products are removed by means of an exhaust tube enveloping the reaction site. This invention permits precise control of an edge exclusion width, resulting in an increase in the number of usable die on a wafer. Wafer edge processing with this invention replaces existing methods that use large volumes of purified water and hazardous chemicals including solvents, acids, alkalis, and proprietary strippers.