Transparent Substrate Recognition Layer for Lithography Alignment
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Solution Overview
Problem
Transparent substrates, such as glass, pose challenges in lithography processing due to their transparency, leading to inefficiencies, misalignment, increased defects, and higher operational costs, as lithography machines struggle to recognize and align these substrates effectively.
Innovation Solution
A film stack for optical devices is created with a glass substrate, featuring a device function layer, a hard mask layer made of chromium, ruthenium, or titanium nitride, and a substrate recognition layer, along with a backside layer, which facilitates recognition and alignment during lithography processing, enabling efficient patterning and etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If transparent substrates are used in lithography processing, then substrate transparency is maintained, but substrate recognition and alignment become difficult
Solution Approach 1:
A recognition layer is introduced as an intermediary between the transparent substrate and the lithography machine's detection system. This layer contains materials with specific optical properties (absorption, reflection, or emission characteristics) that enable the machine to detect and recognize the substrate's presence and position without compromising the substrate's transparency for its intended optical application.
2Adaptability or versatility
If transparent substrates are used in lithography processing, then substrate transparency is maintained, but alignment precision deteriorates
Solution Approach 1:
The recognition layer serves as a mediator that provides alignment markers and reference features visible to the lithography machine's alignment system. These features enable precise positioning and alignment of the transparent substrate during processing while maintaining the substrate's optical transparency for its final application.
3Device complexity
If transparent substrates are processed without recognition layers, then process simplicity is maintained, but productivity decreases
Solution Approach 1:
The recognition layer is applied in advance during substrate preparation, before the lithography processing begins. This preliminary action ensures that the substrate is pre-configured with recognition features, enabling the lithography machine to quickly recognize and process substrates without delays, thereby increasing throughput while maintaining relatively simple overall process flow.
Data Source
AI summary
Aspects of the present disclosure relate generally to methods and apparatus of processing transparent substrates, such as glass substrates. In one implementation, a film stack for optical devices includes a glass substrate including a first surface and a second surface. The film stack includes a device function layer formed on the first surface, a hard mask layer formed on the device function layer, and a substrate recognition layer formed on the hard mask layer. The hard mask layer includes one or more of chromium, ruthenium, or titanium nitride. The film stack includes a backside layer formed on the second surface. The backside layer formed on the second surface includes one or more of a conductive layer or an oxide layer.