Wafer Edge Cleaning via pH-Adjusted Fluid Dispensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Chemical mechanical polishing (CMP) in semiconductor manufacturing often leaves residual metal residues on wafer edges, leading to defects and potential short circuits, despite additional cleaning steps like brush cleaning.
Innovation Solution
A wafer cleaning apparatus and method that includes a polishing unit for CMP, followed by a cleaning dispensing unit directing cleaning fluids, specifically deionized water and a pH-adjusted chemical composition, towards the far edges of the wafer to effectively remove residual materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brush cleaning is used after CMP, then cleaning capability is improved, but metal residues remain on wafer edges causing defects
Solution Approach 1:
The patent changes the chemical parameters of the cleaning solution by adjusting pH levels (using acidic solutions around pH 2-4 or alkaline solutions around pH 10-12) and controlling chemical composition (specific ratios of oxidants, chelating agents, and surfactants) to enhance the removal of metal residues from wafer edges that mechanical brushing cannot eliminate
Solution Approach 2:
The patent introduces chemical intermediaries (cleaning solutions containing oxidants like hydrogen peroxide, chelating agents like EDTA, and surfactants) that mediate between the metal residues and the cleaning process, enabling effective removal through chemical reactions and emulsification that mechanical brushing alone cannot achieve
2Reliability
If additional cleaning steps are added after CMP, then residue removal is improved, but process complexity increases
Solution Approach 1:
The patent merges multiple cleaning functions (chemical etching, emulsification, suspension, and rinsing) into a single integrated cleaning solution formulation and application process, combining oxidants, chelating agents, and surfactants in one solution that performs multiple cleaning actions simultaneously, thereby improving residue removal without proportionally increasing process complexity
Solution Approach 2:
The cleaning solution is designed with multi-functionality to handle various types of residues (metal particles, organic contaminants, and inorganic deposits) through a single application step, using a universal formulation that can address multiple contamination types without requiring separate specialized cleaning processes for each residue type
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
The solution ensures thorough removal of residual metal residues from wafer edges, reducing defects and preventing short circuits by targeting hard-to-reach areas with a combination of deionized water and pH-adjusted cleaning chemicals after CMP.
Implementation Method 1
rinsing with deionized water to suspend residual particles
Implementation Method 2
applying a cleaning chemical containing pH adjuster, such as one or more of HNO3, H2SO4, NH4OH, KOH or organic amine, the cleaning chemical used after CMP of the wafer and being an acid or an alkaline having a pH range from about 2 to about 13
Implementation Method 3
cleaning chemical composition that may include surfactants, chelating agents, oxidants
Implementation Method 4
cleaning chemical composition that may include surfactants, chelating agents, oxidants
Data Source
AI summary
A wafer cleaning apparatus includes a polishing unit used in chemical mechanical polishing (CMP) of a wafer and a cleaning dispensing unit arranged to direct cleaning fluids toward a far edge of the wafer after the CMP of the wafer. A wafer cleaning method includes CMP of a wafer by a polishing unit and directing cleaning fluids toward a far edge of the wafer after the CMP of the wafer by a cleaning dispensing unit. Another method can include CMP, applying deionized water, and applying pH adjuster having a pH range from about 2 to about 13.