Semiconductor Wafer Cleaning via Segmented Spray and Roller Modules
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Solution Overview
Problem
Semiconductor wafers after chemical mechanical polishing are contaminated with polishing agent residues, which must be rapidly and completely removed to prevent surface defects and optimize production efficiency.
Innovation Solution
A method involving sequential cleaning steps, including water spraying, roller cleaning with aqueous solutions containing hydrogen fluoride and surfactants, alkaline dipping, and drying, optimized for high throughput and surface purity, with specific time and pressure controls to prevent surface damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional multi-step cleaning methods are used, then polishing residues are removed, but cleaning time is excessive and throughput is low
Solution Approach 1:
The cleaning process is divided into distinct functional modules: a spray module for initial residue removal, a roller module for mechanical cleaning and drying, and a dip module for final cleaning. This segmentation allows each module to perform its specific function efficiently, reducing overall cleaning time while maintaining high throughput of one wafer every 66 seconds
Solution Approach 2:
The spray module performs preliminary cleaning by removing loose polishing residues before the wafer enters the roller module. This preliminary action prevents subsequent mechanical cleaning steps from having to work harder, reducing total processing time while ensuring complete residue removal
2Speed
If high pressure water spraying is used, then cleaning speed increases, but surface defects are caused
Solution Approach 1:
The patent specifies precise pressure parameters for different cleaning stages: the spray module uses controlled pressure to remove residues without damaging the surface, while the dip module uses an alkaline solution at optimized concentration and temperature. These parameter optimizations enable effective cleaning at high speed while preventing surface defects
3Manufacturing precision
If complete residue removal is achieved, then surface purity is maximized, but cleaning complexity increases
Solution Approach 1:
Different cleaning mechanisms are applied to different aspects of contamination: the spray module handles loose residues, the roller module addresses adhered particles through mechanical action, and the dip module removes organic contaminants through chemical action. This localized approach achieves complete surface purity while keeping each individual module relatively simple
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 method effectively removes polishing residues, achieving surface purity suitable for packaging and significantly reducing particle contamination, with a cycle time of less than 360 seconds and a throughput of at least one wafer per 66 seconds.
Implementation Method 1
both side surfaces of the semiconductor wafer are sprayed at least once with water at a pressure of not more than 1000 Pa
Implementation Method 2
spraying the side surfaces of the semiconductor wafer with an aqueous solution containing hydrogen fluoride
Implementation Method 3
spraying the side surfaces of the semiconductor wafer with an aqueous solution containing hydrogen fluoride and a surfactant
Implementation Method 4
cleaning the semiconductor wafer between rotating rollers with supply of water
Implementation Method 5
dipping the semiconductor wafer into an aqueous alkaline cleaning solution
Implementation Method 6
spraying the side surfaces of the semiconductor wafer with water at a pressure of not more than 20 000 Pa
Implementation Method 7
drying the semiconductor wafer
Data Source
AI summary
A method for cleaning a semiconductor wafer composed of silicon directly after a process of chemical mechanical polishing of the semiconductor wafer includes transferring the semiconductor wafer from a polishing plate to a first cleaning module and spraying both side surfaces of the semiconductor wafer with water at a pressure no greater than 1000 Pa at least once while transferring the semiconductor wafer. The semiconductor wafer is then cleaned between rotating rollers with water. The side surfaces of the semiconductor wafer are sprayed with an aqueous solution containing hydrogen fluoride and a surfactant at a pressure no greater than 70,000 Pa. Subsequently, the side surfaces are sprayed with water at a pressure no greater than 20,000 Pa. The wafer is then dipped into an aqueous alkaline cleaning solution, and then cleaned between rotating rollers with a supply of water. The semiconductor wafer is then sprayed with water and dried.