Photomask Opening Layout for Precise Alignment Key Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor manufacturing processes face defects in alignment keys due to insufficient etching, which hinders accurate alignment and separation of semiconductor chips.
Innovation Solution
A method involving the use of a mask with a light-blocking pattern and light-transmitting areas to form a target opening and auxiliary patterns, ensuring precise etching of alignment keys by concentrating etchant in photo-openings and removing barrier patterns during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching is used to form alignment keys, then the etching process is simple, but insufficient etching occurs causing defects in alignment keys
Solution Approach 1:
The mask opening is segmented into multiple functional regions: a light-transmitting area for forming the target opening and light-blocking patterns (barrier patterns) for forming auxiliary patterns. This segmentation allows the etching process to create both the main alignment key structure and auxiliary support structures in a single step, improving etching precision while managing complexity through functional division.
Solution Approach 2:
The auxiliary patterns are formed as preliminary structures during the etching process. These auxiliary patterns provide support during etching and are subsequently removed to complete the alignment key formation. This preliminary action ensures complete and precise etching by preventing insufficient etching defects while maintaining a manageable mask structure.
2Manufacturing precision
If a simple mask opening is used, then the mask is easy to manufacture, but alignment accuracy deteriorates due to insufficient etching
Solution Approach 1:
The mask opening is divided into a light-transmitting area and light-blocking patterns, creating a segmented structure that enables precise control of the etching process. This segmentation improves alignment accuracy by ensuring complete etching through auxiliary patterns while the mask remains manufacturable using standard photolithography techniques.
Solution Approach 2:
Different regions of the mask opening have different local qualities: the light-transmitting area allows full light transmission for main structure formation, while the light-blocking patterns create auxiliary patterns in specific locations. This local quality differentiation ensures precise alignment key formation without significantly complicating mask manufacturing.
3Reliability
If etching is performed without auxiliary patterns, then the process is faster, but defects occur due to insufficient etching
Solution Approach 1:
The formation of target openings and auxiliary patterns is merged into a single etching step using the patterned mask. This combining of functions ensures reliable alignment key quality by preventing insufficient etching while maintaining manufacturing efficiency, as both structures are created simultaneously rather than requiring separate processing steps.
Solution Approach 2:
The auxiliary patterns are formed as preliminary structures during the etching process that provide support and ensure complete etching. These preliminary structures are then removed in a subsequent step to complete the alignment key. This approach ensures high reliability of alignment keys while managing productivity by integrating the auxiliary pattern formation into the main etching process.
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 approach reduces defects in alignment keys, enhancing the accuracy of chip alignment and separation by forming distinct depressions in the mask and hard mask layers, facilitating precise semiconductor chip production.
Implementation Method 1
a light-blocking pattern, in the mask opening, configured to block light
Implementation Method 2
a light-transmitting area, in the mask opening, in which the light is transmitted
Data Source
AI summary
The method may include forming a photoresist over a first structure, forming a photoresist pattern by removing a portion of the photoresist through a mask including a mask opening, wherein the mask opening includes a light-blocking pattern and a light-transmitting area, forming, by etching the first structure according to the photoresist pattern, a target opening corresponding to the mask opening and an auxiliary pattern corresponding to the light-blocking pattern of the mask opening, wherein the target opening is formed to have a first depth, wherein the auxiliary pattern is formed to have a second depth that is shallower than the first depth, and wherein the auxiliary pattern is located in the target opening and is implemented as a part of the first structure, and forming an alignment key by removing the auxiliary pattern from within the target opening.