Plasma Dicing Cleanup for Low-Temperature Fluorine Removal
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Solution Overview
Problem
Existing cleaning methods for removing fluorine-containing contaminants from metallic features on substrates after plasma dicing are not effective in maintaining the workpiece within strict thermal budgets, particularly when using temperature-sensitive carrier sheets.
Innovation Solution
A method involving alternating sputter etch and chemical etch steps using an inductively coupled plasma apparatus, where the sputter etch step employs argon and the chemical etch step uses O2 or O3, to effectively remove fluorine-containing contaminants while maintaining a low thermal load on the workpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sputter etching is used to remove fluorine-containing contaminants from metallic features, then cleaning effectiveness is improved, but thermal load on the workpiece increases causing damage to temperature-sensitive carrier sheets
Solution Approach 1:
The cleaning process is divided into multiple alternating cycles of sputter etching and chemical etching. Each sputter etch step (using Ar plasma) is followed by a chemical etch step (using O2 or O3 plasma), allowing the sputter etching to be performed in short intervals rather than continuously, thereby reducing cumulative thermal load while maintaining cleaning effectiveness
Solution Approach 2:
The sputter etching is performed in an argon plasma environment, which is inert and does not chemically react with the metallic features. This allows physical removal of fluorine-containing contaminants through ion bombardment without the need for high temperatures that would damage the carrier sheet
2Manufacturing precision
If longer treatment duration is used to remove surface contaminants, then cleaning effectiveness is improved, but thermal load accumulates causing damage to carrier sheets
Solution Approach 1:
The cleaning process uses periodic alternating cycles between sputter etching (Ar plasma) and chemical etching (O2/O3 plasma). This periodic action allows the sputter etching to occur in repeated short bursts rather than continuous operation, achieving thorough contaminant removal over time while allowing thermal management between cycles
Solution Approach 2:
The alternating sequence of sputter etching and chemical etching ensures continuous progress in contaminant removal. The chemical etch steps prepare the surface and remove oxidation products, enabling the sputter etch steps to remain effective throughout the process without requiring extended idle periods
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 method reduces surface contaminants such as fluorine-containing compounds with a shorter treatment duration, maintaining the workpiece at a lower temperature to prevent damage to temperature-sensitive carrier sheets, and improving the quality and reliability of devices.
Implementation Method 1
sustaining an inductively coupled plasma of the sputter gas or gas mixture so as to sputter etch the substrate
Implementation Method 2
sustaining an inductively coupled plasma of the O2 and/or O3 gas) so as to chemically etch the substrate
Implementation Method 3
chemical etch step comprising the sub-steps of introducing O2 gas and/or O3 gas) into the chamber, and sustaining an inductively coupled plasma of the O2 and/or O3 gas) so as to chemically etch the substrate
Data Source
AI summary
A metallic feature on a substrate is subjected to a plasma dicing process and is cleaned. The workpiece has a carrier sheet attached to a frame member. The carrier sheet carries the substrate. The workpiece is provided on a workpiece support disposed within a chamber of an inductively coupled plasma apparatus. A sputter etch step is performed, including introducing a sputter gas or gas mixture into the chamber and sustaining an inductively coupled plasma of the sputter gas or gas mixture so as to sputter etch the substrate. A chemical etch step also is performed, including introducing O2 gas and/or O3 gas) into the chamber and sustaining an inductively coupled plasma of the O2 and/or O3 gas) so as to chemically etch the substrate. The sputter etch step and chemical etch step can be repeated.