Plasma Etching with DC Pulse Bias for Resist Scum Removal
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in effectively removing photoresist film scum and suppressing defects in resist patterns during plasma etching, particularly with EUV resist films containing metals like tin.
Innovation Solution
A plasma processing method involving the use of a DC pulse voltage applied to a substrate support within a plasma processing chamber, combined with specific gas selection and RF signal application, to selectively remove photoresist film scum and etch underlying films while minimizing pattern defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma processing is used to remove photoresist film scum, then the etching process can proceed, but pattern defects occur and manufacturing precision deteriorates
Solution Approach 1:
The patent applies a DC pulse voltage to the substrate support before the main plasma etching process to pre-remove photoresist film scum. This preliminary action prevents pattern defects that would occur during subsequent etching, thereby improving manufacturing precision while eliminating the harmful scum effect
Solution Approach 2:
The patent uses periodic DC pulse voltage applied at specific intervals during the plasma processing sequence. The pulse voltage is applied in a periodic manner (before etching, and optionally during intermediate stages) to continuously prevent scum formation and maintain pattern integrity throughout the etching process
2Manufacturing precision
If DC pulse voltage is applied to remove photoresist scum, then pattern integrity is maintained, but process complexity increases
Solution Approach 1:
The substrate support is designed to serve multiple functions: it not only holds the substrate during processing but also acts as an electrode for applying DC pulse voltage. This multi-functionality allows scum removal and pattern protection without adding separate complex apparatus, thereby reducing overall device complexity while maintaining pattern integrity
Solution Approach 2:
The patent changes the electrical parameter (applying DC pulse voltage) of the substrate support to enable scum removal. By modifying the electrical state of an existing component rather than adding new hardware, the process achieves enhanced pattern integrity with minimal increase in device complexity
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 reduces photoresist film scum and maintains pattern integrity by controlling the etching process, ensuring high selectivity and precision in film removal.
Implementation Method 1
forming plasma from a processing gas supplied into the plasma processing chamber
Implementation Method 2
selectively removing a part of the photoresist film with respect to the etching film, including forming plasma from a processing gas supplied into the plasma processing chamber and applying a DC pulse voltage to the substrate support
Data Source
AI summary
A plasma processing method includes disposing a substrate on a substrate support disposed in a plasma processing chamber of a plasma processing apparatus, the substrate having an etching film and a photoresist film disposed on the etching film; and selectively removing a part of the photoresist film with respect to the etching film, including forming plasma from a processing gas supplied into the plasma processing chamber and applying a DC pulse voltage to the substrate support.