Wafer Backside Cleaning With Targeted Brush Path Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Contaminants on the backside of semiconductor wafers can cause inaccurate exposure and reduce the quality of the photoresist pattern, leading to unsatisfactory image formation in the lithography process.
Innovation Solution
A wafer cleaning system that includes a wafer edge exposure apparatus and a backside treatment apparatus, which uses a brush element and control device to differentiate between clear and unclear areas on the wafer's backside, employing varying speeds and forces for enhanced cleaning of contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a uniform cleaning process is applied to the entire wafer backside, then the cleaning coverage is complete, but the cleaning efficiency is reduced due to unnecessary processing of clean areas
Solution Approach 1:
The patent applies different cleaning parameters (speed, force, brush engagement) to different regions of the wafer backside based on contaminant presence. The inspection device identifies contaminated areas, and the cleaning device adjusts its operation locally to match the actual contamination level, avoiding uniform over-cleaning of already clean areas.
Solution Approach 2:
The cleaning device dynamically adjusts its operating parameters during the cleaning process. The brush element's engagement depth, rotational speed, and applied force are varied in real-time based on feedback from the inspection device, allowing the system to adapt to different contamination scenarios across the wafer surface.
2Reliability
If high cleaning force is applied to remove all contaminants, then contaminant removal is effective, but wafer surface damage may occur
Solution Approach 1:
The patent applies cleaning force locally only where contaminants are detected. The inspection device maps contaminant locations and severity, and the cleaning device concentrates its action only on those specific areas, leaving clean areas untouched and minimizing the risk of surface damage.
Solution Approach 2:
The patent uses partial action by applying cleaning force only to the extent necessary for removing detected contaminants. Rather than applying maximum force uniformly across the entire wafer, the system applies just enough cleaning action in specific locations to achieve the desired contamination removal without excess that could cause damage.
3Measurement precision
If the wafer is cleaned before inspection, then the inspection accuracy is improved, but the overall process time increases
Solution Approach 1:
The patent performs inspection before cleaning as a preliminary action to identify where cleaning is actually needed. This reverse sequence allows the system to skip cleaning steps in areas that are already clean, thereby reducing total process time while still achieving the inspection accuracy needed to guide the subsequent targeted cleaning.
Solution Approach 2:
The inspection device provides information that enables the cleaning device to self-regulate its operation. By knowing the contaminant distribution in advance, the cleaning system can autonomously adjust its parameters and focus only on necessary areas, eliminating the need for time-consuming uniform cleaning of the entire wafer surface.
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 system effectively removes contaminants, ensuring a flat wafer surface, accurate exposure, and improved photoresist quality by tailoring cleaning processes to specific areas based on contaminant types and locations.
Implementation Method 1
A wafer cleaning system that includes a wafer edge exposure apparatus and a backside treatment apparatus, which uses a brush element and control device to differentiate between clear and unclear areas on the wafer's backside, employing varying speeds and forces for enhanced cleaning of contaminants
Implementation Method 2
employing varying speeds and forces for enhanced cleaning of contaminants
Data Source
AI summary
A wafer cleaning method for cleaning contaminants on a wafer is provided, wherein the backside of the wafer has a clear area and an unclear area, and the contaminants are located in the unclear area. The wafer cleaning method includes inspecting the backside of the wafer and generating an inspection signal by an inspection device. The wafer cleaning method includes generating a control signal according to the inspection signal by a process module, wherein the control signal includes movement information of a brush element according to coordinates of the contaminants obtained from the inspection signal. The wafer cleaning method includes controlling the brush element to clean the contaminants on the backside of the wafer according to the control signal by a control device along a predetermined path.