Semiconductor Wafer Cleaning Sequence for Edge Defect Reduction
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Solution Overview
Problem
Existing semiconductor wafer cleaning methods cause defects, particularly at the edge of the wafer, which can disrupt subsequent component manufacturing processes.
Innovation Solution
A multi-step cleaning process is employed, starting with a pre-cleaning step on the front side using water, followed by ozonized water and HF treatments, and culminating in a joint cleaning of both sides with ozonized water and HF, with specific parameters for each step to minimize defect occurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-step cleaning process with ozonized water and HF is applied to both sides of the semiconductor wafer, then cleaning effectiveness is improved, but defect patterns occur at the wafer edge
Solution Approach 1:
The cleaning process is divided into separate front-side and back-side cleaning operations. The front side is cleaned first with water, then ozonized water, then rinsed. The back side is cleaned separately with ozonized water and HF treatments. This segmentation prevents defect patterns at the wafer edge that occur when both sides are cleaned simultaneously or in sequence without proper separation.
Solution Approach 2:
The front side of the wafer is pre-cleaned with water and ozonized water before the back side cleaning process. This preliminary cleaning establishes a clean state on the front side that prevents defect patterns from appearing during subsequent back-side cleaning operations with ozonized water and HF.
2Manufacturing precision
If conventional cleaning methods are used to remove contamination, then particle removal is improved, but defect patterns measurable by light scattering occur
Solution Approach 1:
The cleaning process uses specific parameter combinations: water at controlled flow rates for pre-cleaning, ozonized water with specific ozone concentrations for oxidation-based cleaning, and HF solutions at controlled concentrations for chemical cleaning. These parameter changes enable effective particle removal while preventing the formation of defect patterns that would be detectable by light scattering measurements.
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 significantly reduces defect patterns, especially at the wafer edge, enhancing the reliability of semiconductor components by minimizing defects measurable through light scattering measurements.
Implementation Method 1
a first cleaning step for cleaning with ozonized water
Implementation Method 2
a treatment step with a liquid containing HF
Implementation Method 3
The liquids are applied to the rotating semiconductor wafer and accelerated by centrifugal force towards the wafer edge
Implementation Method 4
the addition of a vapor that reduces the surface tension of the liquid film (e.g., isopropanol)
Data Source
Figure 1
AI summary
A method for cleaning the front and back sides of a semiconductor wafer, comprising in a given sequence: the cleaning of the front side of the semiconductor wafer, comprising in a given sequence: (1) a pre-cleaning step with water, such that the front side is still wet when the next cleaning step begins, (2) a first cleaning step for cleaning with ozonated water followed by a rinsing step with purified water, (3) a second cleaning step comprising a treatment step with ozonated water followed by a treatment step with an RF-containing liquid, (4) a third cleaning step for cleaning with ozonated water followed by a rinsing step with purified water, comprising the joint cleaning of the front and back sides of the semiconductor wafer: a fourth cleaning step comprising a treatment step with ozonated water.which is followed by a treatment step with an RF-containing liquid, and a drying step in which both sides of the semiconductor wafer are dried.