Semiconductor Line Formation Using Anisotropic Etching Spacers
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Solution Overview
Problem
Existing methods for forming lines in semiconductor constructions often result in adjacent lines joining undesirably, requiring additional masking and etching steps to prevent shorting, which complicates the fabrication process and reduces throughput.
Innovation Solution
The method involves patterning photoresist with a specific topography that prevents adjacent lines from joining, using anisotropic etching to form lines without the need for prior art masking and etching steps, and transferring this topography to underlying materials to create pitch-doubled lines without end joining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional methods are used to form lines in semiconductor constructions, then lines can be formed, but adjacent lines join undesirably requiring additional masking and etching steps
Solution Approach 1:
The patent applies preliminary action by forming a mandrel structure with spaced-apart ends before depositing the conductive material. This pre-positioning of the mandrel prevents adjacent lines from joining during the formation process, eliminating the need for subsequent masking and etching steps to separate them. The mandrel's spatial arrangement is established in advance to control the final line configuration.
Solution Approach 2:
The patent uses a mandrel as an intermediary structure to achieve the desired line formation. The mandrel serves as a temporary mediator that defines the spacing and positioning of adjacent lines during deposition. After the conductive material is formed around the mandrel, the mandrel is removed, leaving the separated lines. This intermediary structure enables precise line separation without requiring additional masking and etching processes.
2Manufacturing precision
If additional masking and etching steps are used to prevent line shorting, then line separation is achieved, but fabrication throughput is reduced
Solution Approach 1:
The patent extracts the line separation function from the conventional multi-step masking and etching process by using a mandrel structure that inherently prevents line joining. The mandrel is removed after serving its purpose of defining line spacing, leaving the separated conductive lines without requiring additional separation steps. This extraction of the separation function into the mandrel design eliminates unnecessary process steps.
Solution Approach 2:
The mandrel structure provides self-service by automatically maintaining the spaced-apart configuration of adjacent lines during the deposition process. The physical presence of the mandrel with its spaced ends inherently prevents the conductive material from forming continuous adjacent lines, eliminating the need for external masking and etching interventions to achieve line separation.
3Reliability
If mandrels with spaced-apart ends are used, then adjacent lines are prevented from joining, but additional mandrel formation steps are required
Solution Approach 1:
The patent merges the mandrel formation and line separation functions into a single integrated process. The mandrel structure is formed with spaced-apart ends that simultaneously serve as the template for conducting material deposition and as the physical barrier preventing line joining. This merging of functions into the mandrel design achieves reliable line separation while minimizing the number of discrete process steps.
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 enhances the quality and uniformity of semiconductor line formation, improves fabrication throughput by eliminating unnecessary masking and etching steps, and ensures that adjacent lines do not short, thereby simplifying the process and improving overall line quality.
Implementation Method 1
using anisotropic etching to form lines without the need for prior art masking and etching steps
Implementation Method 2
patterning photoresist with a specific topography that prevents adjacent lines from joining, using anisotropic etching to form lines
Data Source
AI summary
In some embodiments, an opening is formed through a first material, and sidewall topography of the opening is utilized to form a pair of separate anistropically etched spacers. The spacers are utilized to pattern lines in material underlying the spacers. Some embodiments include constructions having one or more openings which contain steep sidewalls joining to one another at shallow sidewall regions. The constructions may also contain lines along and directly against the steep sidewalls, and spaced from one another by gaps along the shallow sidewall regions.