Light-Absorbing Interfacial Layer for High-Resolution Lithography
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Solution Overview
Problem
Current semiconductor packaging and PCB fabrication technologies face challenges in reducing fine line spacing of interconnects and increasing input/output density due to unwanted surface reflection during high-resolution lithography, which affects the fidelity and sharpness of features, especially when close to metal layers.
Innovation Solution
An interfacial layer with light-absorbing properties, formed using bi-functional molecules, is applied to the metal layer to enhance adhesion and reduce surface reflection, allowing for improved lithography techniques and finer feature definition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high resolution lithography (HRL) using electron beam is used to decrease fine line spacing of interconnects, then interconnect bandwidth and I/O density increase, but unwanted surface reflection occurs affecting feature fidelity and sharpness
Solution Approach 1:
An interfacial layer is introduced between the metal layer and the resist layer to act as an intermediary that absorbs excess electron beam energy. This prevents unwanted surface reflection from the metal layer while allowing the electron beam to effectively expose the resist layer, thereby maintaining feature fidelity and sharpness during HRL patterning.
Solution Approach 2:
The patent converts the harmful surface reflection effect into a beneficial outcome by using the interfacial layer to absorb the reflected electron beam energy. The layer that would otherwise cause harmful reflection is transformed into a useful energy absorption medium that protects the lithography process while enabling continued use of HRL for high-density interconnect fabrication.
2Productivity
If fine line spacing of interconnects is decreased to increase I/O density, then more interconnects can be formed, but surface reflection from metal layers degrades lithography quality
Solution Approach 1:
The interfacial layer serves as a mediator between the metal layer and the lithography system, absorbing electron beam energy that would otherwise cause surface reflection. This enables the fabrication of high-density interconnect patterns with maintained lithography quality, resolving the contradiction between increasing I/O density and preserving manufacturing precision.
3Manufacturing precision
If electron beam energy is increased to improve resist exposure, then feature definition improves, but surface reflection from metal layer increases
Solution Approach 1:
The interfacial layer acts as an energy-absorbing intermediary positioned between the metal layer and the resist layer. It absorbs excess electron beam energy that would cause surface reflection, allowing high-energy electron beams to be used for improved feature definition without generating harmful surface reflection from the metal layer.
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 interfacial layer minimizes unwanted surface reflection, enabling the creation of denser interconnects with smaller fine line spacing, thereby increasing interconnect bandwidth and input/output density, which enhances the performance and miniaturization of semiconductor packages and PCBs.
Implementation Method 1
An interfacial layer with light-absorbing properties, formed using bi-functional molecules, is applied to the metal layer to enhance adhesion and reduce surface reflection
Data Source
AI summary
Embodiments described herein are directed to interfacial layers and techniques of forming such interfacial layers. An interfacial layer having one or more light absorbing molecules is on a metal layer. The light absorbing molecule(s) may comprise a moiety exhibiting light absorbing properties. The interfacial layer can assist with improving adhesion of a resist layer to the metal layer and with improving use of one or more lithography techniques to fabricate interconnects and/or features using the resist and metal layers for a package substrate, a semiconductor package, or a PCB. For one embodiment, the interfacial layer includes, but is not limited to, an organic interfacial layer. Examples of organic interfacial layers include, but are not limited to, self-assembled monolayers (SAMs), constructs and/or variations of SAMs, organic adhesion promotor moieties, and non-adhesion promoter moieties.