Semiconductor Pattern Formation Using Spacer Film
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Solution Overview
Problem
Highly-integrated semiconductor devices require patterns with varying widths and spacings, which existing manufacturing processes struggle to achieve efficiently, especially in forming uniform patterns across different areas.
Innovation Solution
A method involving the sequential formation of mask and sacrificial layers on a substrate, followed by etching and spacer film deposition to create patterns with specific widths and spacings, allowing for the removal of sacrificial layers and subsequent etching of the mask layer to form desired patterns, enabling the formation of patterns with various widths in different areas while maintaining uniformity within each area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography is used to form patterns, then the manufacturing process is simple, but it is difficult to form patterns with various widths and fine pitches simultaneously
Solution Approach 1:
The substrate is divided into first and second areas with different pattern requirements. In the first area, sacrificial pattern units are formed with specific widths and spacings, while in the second area, different sacrificial pattern units are formed. This segmentation allows each area to be optimized independently for its specific pattern width and spacing requirements, enabling the formation of patterns with various widths and fine pitches simultaneously without requiring a completely different manufacturing process for each area.
Solution Approach 2:
The invention introduces a vertical dimension by forming a spacer film that conformally covers the sacrificial pattern units. The spacer film thickness controls the final pattern dimensions, allowing precise control of pattern widths through thin film deposition rather than relying solely on photolithography exposure parameters. This dimensional transition from 2D photolithography to 3D spacer-based patterning enables finer pitch control and various pattern widths.
2Manufacturing precision
If multiple photomasks are used to form patterns with various widths, then pattern precision is improved, but the number of manufacturing steps increases
Solution Approach 1:
Sacrificial pattern units are formed preliminarily in both the first and second areas before the final spacer formation. These sacrificial patterns serve as templates that define the desired final pattern dimensions. By preparing these preliminary structures, the actual spacer-based pattern transfer becomes a single-step process that simultaneously creates precise patterns of various widths across different areas, eliminating the need for multiple sequential photomask steps.
Solution Approach 2:
The spacer film serves multiple functions: it defines the final pattern width, acts as an etch mask, and enables pattern transfer to the underlying substrate. A single spacer formation step universally creates precise patterns across both the first and second areas, regardless of the specific width requirements in each area. This multi-functionality replaces what would otherwise require multiple specialized photomask steps.
3Ease of manufacture
If a single spacer film is used to form patterns in different areas, then process simplicity is improved, but achieving uniform patterns with various widths is difficult
Solution Approach 1:
The sacrificial pattern units are designed with different local characteristics for different areas. In the first area, sacrificial pattern units have specific widths and spacings optimized for that region's requirements, while in the second area, different sacrificial pattern unit dimensions are used. When the uniform spacer film is formed over these area-specific sacrificial patterns, the local variations in sacrificial pattern dimensions are transferred to the final patterns, achieving both uniformity (from the uniform spacer) and area-specific width variations (from the local sacrificial pattern design).
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 method allows for the stable and simple formation of patterns with varying widths and spacings, enhancing the integration and performance of semiconductor devices by enabling precise pattern formation across different areas with a single spacer film of uniform thickness.
Implementation Method 1
forming a spacer film conformally covering the plurality of first sacrificial pattern units and the plurality of second sacrificial pattern units
Implementation Method 2
etching the sacrificial layer in the first area of the substrate to form a plurality of first sacrificial pattern units
Data Source
AI summary
A method of forming a pattern of a semiconductor device includes forming a mask and a sacrificial layer on a substrate, etching the sacrificial layer in a first area of the substrate to form first units, each having a first width and a first distance from an adjacent unit, etching the sacrificial layer in a second area of the substrate to form second units, each having a second width equal to the first distance and being spaced apart from an adjacent unit by a second distance equal to the first width, forming a spacer conformally covering the first and second units, the spacer having a first thickness and being merged between the second units, removing a portion of the spacer on upper surfaces of the first and second units, and etching the mask in a region from which first and second units have been removed.