Sacrificial Mask Alignment for Semiconductor Node Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current double patterning technologies face challenges in accurately forming non-uniform or complicated line-shaped patterns, particularly in node separation areas of semiconductor devices, due to difficulties in aligning masks with small cut-off portions, leading to misalignment and undesired pattern cuts.
Innovation Solution
A method involving the formation of a sacrificial mask pattern with spacer lines and a mask pattern to create a pattern structure with improved alignment margins, allowing for precise positioning of cut-off portions in node separation areas by using spacer spaces and a mask pattern that covers connection portions, enabling accurate node separation despite fine pattern widths and gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If double patterning technology is used to form fine line-shaped patterns, then line width and gap distance can be reduced below photolithography resolution limits, but alignment precision deteriorates when forming cut-off portions in node separation areas
Solution Approach 1:
A sacrificial mask pattern is introduced as an intermediary element between the target layer and the final mask pattern. This sacrificial mask includes connection portions that bridge discontinuous line segments, providing a reference structure for subsequent mask alignment. The sacrificial mask is temporarily retained during etching to ensure accurate positioning of cut-off portions, then removed after serving its alignment function.
Solution Approach 2:
The sacrificial mask pattern is formed in advance before the final mask pattern alignment step. This preliminary structure establishes reference points and connection portions that guide the subsequent mask positioning, ensuring that cut-off portions are accurately formed at desired locations before the sacrificial mask is removed.
2Reliability
If mask pattern is used to form cut-off portions in node separation areas, then node separation can be achieved, but alignment accuracy deteriorates due to small size of cut-off portions
Solution Approach 1:
The sacrificial mask pattern serves as a mediator that provides physically larger reference structures (connection portions) for mask alignment. These connection portions are larger than the final cut-off portions, making them easier to align with the mask pattern. The sacrificial mask bridges the gap between discontinuous line segments, creating visible reference points that improve mask positioning accuracy during node separation.
3Ease of manufacture
If conventional double patterning is used for node separation, then line-shaped patterns can be formed, but misalignment occurs between mask pattern and cut-off portions leading to undesired pattern cuts
Solution Approach 1:
The sacrificial mask pattern acts as an intermediary alignment reference that prevents misalignment between the mask pattern and cut-off portions. By providing connection portions that span across discontinuous line segments, the sacrificial mask creates a stable reference framework that guides mask positioning, ensuring that etching occurs at the correct locations and preventing undesired pattern cuts.
Solution Approach 2:
The sacrificial mask pattern is formed preliminarily to establish accurate reference points before mask alignment. This preliminary structure ensures that subsequent etching operations occur at precisely the desired locations, preventing misalignment and undesired pattern cuts while maintaining ease of manufacture through a systematic multi-step process.
Data Source
AI summary
In a method of forming a pattern structure, a cut-off portion of the node-separated line of a semiconductor device is formed by a double patterning process by using a connection portion of the sacrificial mask pattern and the mask pattern to thereby improve alignment margin. The alignment margin between the mask pattern and the sacrificial mask pattern is increased to an amount of the length of the connection portion of the sacrificial mask pattern. The lines adjacent to the node-separated line include a protrusion portion protruding toward the cut-off portion of the separated line.