Semiconductor Spacer Double Patterning for Multiple Critical Dimensions
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Solution Overview
Problem
Current semiconductor fabrication methods require multiple masks to create features with multiple critical dimensions and pitches, which is costly and inefficient, especially for 22 nanometer technology nodes and beyond.
Innovation Solution
A method using only two masks to form semiconductor devices with multiple critical dimensions and pitches by forming mandrels with different widths, depositing sidewall spacers, and etching the target layer between the mandrels and fillers, allowing for the creation of features with different dimensions using a reduced number of masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple masks are used to form features with multiple critical dimensions and pitches, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent segments the mandrel structures into different width categories (first mandrels with first width, second mandrels with second width) that are formed simultaneously using a single mask. This segmentation allows different critical dimensions to be defined by different mandrel widths rather than requiring separate masks for each dimension, thereby reducing mask count while maintaining precision for multiple critical dimensions.
Solution Approach 2:
The single mask serves multiple functions by defining both first mandrels and second mandrels with different widths in the same lithography step. This multi-functionality eliminates the need for separate masks for each critical dimension, reducing device complexity and cost while achieving the desired manufacturing precision for multiple feature sizes.
2Manufacturing precision
If multiple masks are used to form features with multiple critical dimensions and pitches, then manufacturing precision is improved, but production cost increases
Solution Approach 1:
The mask pattern is segmented to include both first mandrel regions and second mandrel regions with different widths. This segmentation enables a single mask to define multiple critical dimensions, eliminating the need for multiple expensive masks and thereby reducing production cost while maintaining the precision required for forming features with different critical dimensions.
Solution Approach 2:
The single mask is designed with multi-functionality to define both first mandrels and second mandrels in one lithography step. This universal mask replaces multiple specialized masks, significantly reducing the cost of manufacture while achieving the same manufacturing precision for multiple critical dimensions that would otherwise require separate masks.
3Manufacturing precision
If multiple etching steps with multiple masks are used, then formation of multiple critical dimensions is achieved, but productivity decreases
Solution Approach 1:
The patent performs preliminary action by forming both first mandrels and second mandrels with different widths in a single lithography step using one mask. This preliminary definition of multiple mandrel types eliminates the need for subsequent lithography steps to create additional mandrel structures, thereby reducing the total number of etching steps required while maintaining precision for multiple critical dimensions.
Solution Approach 2:
The patent merges the formation of first mandrels and second mandrels into a single lithography and etching process. By combining what would traditionally require separate masks and etching steps into one unified process, productivity is improved while still achieving the precise formation of multiple critical dimensions through the different mandrel widths.
Data Source
AI summary
A semiconductor device is formed with sub-resolution features and at least one additional feature having a relatively larger critical dimension using only two masks. An embodiment includes forming a plurality of first mandrels, having a first width, and at least one second mandrel, having a second width greater than the first width, overlying a target layer using a first mask, forming sidewall spacers along the length and width of the first and second mandrels, forming a filler adjacent each sidewall spacer, the filler having the first width, removing the filler adjacent sidewall spacers along the widths of the first and second mandrels using a second mask, removing the sidewall spacers, and etching the target layer between the filler and the first and second mandrels, thereby forming at least two target features with different critical dimensions. Embodiments further include using a third mask to form a semiconductor device having further features with a different critical dimension, but the same pitch, as the sub-resolution features.