Metal Oxide Underlayer for Resist Pattern Standing Waves
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Solution Overview
Problem
In semiconductor device production, resist underlayer films on metal substrates like copper fail to suppress reflection adequately, leading to standing waves in the resist pattern, which affects film thickness uniformity and etching burdens.
Innovation Solution
Forming a metal oxide film on the substrate through oxidation treatments like heating in oxygen or ozone, followed by applying a resist underlayer film and a resist layer, and then patterning, to reduce exposure reflectance and standing waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the thickness of the resist underlayer film is reduced to improve film thickness uniformity, then conformal properties are improved, but reflection from the substrate cannot be suppressed, causing standing waves in the resist pattern
Solution Approach 1:
The patent introduces an intermediary layer (adhesion promoter or primer) between the metal substrate and the resist underlayer film. This intermediary layer serves as a mediator that prevents direct optical reflection from the metal substrate while maintaining film adhesion, thereby suppressing standing waves without requiring the resist underlayer film to be extremely thin
Solution Approach 2:
The patent employs composite material structures by combining multiple layers with different optical and adhesive properties. The stack consists of the metal substrate, intermediary layer, and resist underlayer film, where each layer contributes specific properties: the metal substrate provides structural support, the intermediary layer provides adhesion and optical isolation, and the resist underlayer film provides conformal coverage and pattern definition
2Manufacturing precision
If a resist underlayer film is applied on a metal substrate to achieve conformal properties, then film thickness uniformity is improved, but exposure reflectance increases, causing standing waves in the resist pattern
Solution Approach 1:
The intermediary layer acts as an optical mediator that reduces exposure reflectance from the metal substrate. By placing this layer between the substrate and the resist underlayer film, it prevents harmful reflections during exposure while allowing the resist underlayer film to maintain its conformal properties and adhesion to the substrate
3Device complexity
If the resist underlayer film is made thinner to reduce etching burden, then etching complexity is reduced, but reflection suppression becomes insufficient, leading to standing waves
Solution Approach 1:
The intermediary layer serves as a dual-function element that reduces the required thickness of the resist underlayer film for etching protection while simultaneously providing optical isolation to suppress reflections. This allows the resist underlayer film to be thinner with adequate etching protection, as the intermediary layer compensates for the reduced thickness in terms of optical performance
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 standing waves in the resist pattern, achieving better film uniformity and rectangular form quality, thereby improving semiconductor device production.
Implementation Method 1
a metal oxide film (for example, a copper oxide film) has a high n/k (refractive index/absorption coefficient) value with respect to, for example, an i-line (365 nm)... the exposure reflectance from a substrate can be reduced
Data Source
AI summary
A semiconductor device manufacturing process, forming a multilayer structure of a metal oxide (e.g., copper oxide) and a resist underlayer film on a stepped metal substrate reduces exposure reflectance from the substrate, thereby reducing standing waves of the resist pattern (defects caused by reflection) and provides a favorable rectangular resist pattern on the substrate. A pattern-equipped substrate manufacturing method includes: a step for performing an oxidation treatment on a substrate containing metal on a surface thereof to form a metal oxide film on the substrate surface; a step for applying a resist on the metal oxide film and conducting baking to form a resist film; a step for exposing a semiconductor substrate covered by the metal oxide film and the resist; and a step for developing the exposed resist film and conducting patterning.