Single-Wafer Cleaning for Front-Back Roughness Control
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Solution Overview
Problem
Existing wafer cleaning technologies struggle to maintain different degrees of surface roughness on the front and back sides of a wafer, leading to issues like impurity particle transfer during semiconductor manufacturing.
Innovation Solution
A single-wafer type wafer cleaning apparatus and method that uses different chemicals for the front and back sides of a wafer, such as ozonated water for the front side and hydrogen fluoride for the back side, to control surface roughness independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the same cleaning process is applied to both front and back sides of the wafer, then the cleaning process is simple and efficient, but the wafer back side becomes too smooth causing slippage and impurity particle generation
Solution Approach 1:
The patent applies different cleaning conditions to different parts of the wafer: the front side receives standard cleaning while the back side receives enhanced cleaning with additional chemicals (ozone water and/or HF) and higher rotation speeds. This local differentiation creates the desired rougher back surface to prevent slippage without unnecessarily complicating the overall cleaning process.
Solution Approach 2:
The cleaning process is segmented into distinct phases: front side cleaning, back side cleaning with different chemical compositions, and back side cleaning with different rotation parameters. This segmentation allows independent optimization of each cleaning zone to achieve the dual goal of effective cleaning and controlled surface roughness.
2Manufacturing precision
If different chemicals are used for front and back sides of the wafer, then different surface roughness can be achieved, but the chemical consumption and process complexity increase
Solution Approach 1:
The patent applies chemicals selectively only where needed: ozone water and HF are applied exclusively to the back side rather than the entire wafer surface. This partial application achieves the required surface roughness differentiation while minimizing overall chemical consumption compared to treating the whole wafer with multiple chemicals.
3Object-generated harmful factors
If the wafer back side is cleaned more aggressively to increase roughness, then slippage is reduced, but cleaning precision and wafer surface quality may deteriorate
Solution Approach 1:
The patent controls the degree of surface roughness by adjusting cleaning parameters: chemical concentration (ozone water and HF ratios), rotation speed during back side cleaning, and exposure time. These parameter variations allow precise control over the roughness level to achieve sufficient slippage prevention while maintaining acceptable surface quality for subsequent processing.
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 approach effectively minimizes impurity particle transfer by maintaining a rougher back side compared to the front side, reducing slippage and enhancing manufacturing yield in the semiconductor industry.
Implementation Method 1
a first chemical, that is, ozonated water, is supplied to a front side of a wafer
Implementation Method 2
a second chemical, that is, hydrogen fluoride, is supplied to a back side of the wafer
Data Source
AI summary
The present invention presents a single wafer-type wafer cleaning device and a single wafer-type method for controlling the surface roughness of a wafer, in which, in a wafer cleaning process, mutually different cleaning processes are carried out on the respective two sides of a wafer, and also, mutually different chemicals are used depending on the side of the wafer being cleaned, thereby enabling the respective roughness of the two sides to differ. The single wafer-type wafer cleaning device comprises a spin chamber, a first chemical supply device, a second chemical supply device and a third chemical supply device.