Hardmask Composition for Multiple Dark Field Exposures
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Solution Overview
Problem
Existing microelectronic fabrication processes, particularly in photolithography, face challenges in achieving high feature density with small critical dimensions due to the need for multiple exposure techniques that require additional hardmask layers and dry-etching steps, which increase processing time and cost.
Innovation Solution
A method involving a hardmask composition with a polymer and photoacid generator, applied to a substrate, where the hardmask layer is thermally crosslinked and used in conjunction with photosensitive compositions for multiple exposure processes without the need for additional hardmask layers or dry-etching, allowing pattern transfer through developer and solvent removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple exposure processes are used to achieve high feature density with small critical dimensions, then manufacturing precision is improved, but device complexity and processing time increase due to requiring additional hardmask layers and dry-etching steps
Solution Approach 1:
The patent combines the hardmask layer and photosensitive composition into a single integrated layer. The hardmask composition contains both the hardmask polymer and the photosensitive composition, eliminating the need for separate hardmask and photoresist layers. This merging reduces the number of process steps while maintaining the ability to perform multiple exposures for high-density patterning.
Solution Approach 2:
The integrated hardmask photosensitive composition serves multiple functions simultaneously: it acts as a hardmask for etching protection, a photosensitive layer for pattern formation, and a developer-resistant layer. This multi-functionality eliminates the need for separate hardmask application steps between exposures, reducing process complexity while enabling high-precision multiple exposure patterning.
2Manufacturing precision
If multiple exposure processes are used to achieve high feature density with small critical dimensions, then manufacturing precision is improved, but productivity decreases due to increased processing time from additional hardmask reapplication steps
Solution Approach 1:
The patent merges the hardmask and photosensitive compositions into a single layer that remains on the substrate throughout multiple exposure cycles. This eliminates the time-consuming hardmask reapplication step between exposures, significantly reducing total processing time while maintaining the precision benefits of multiple exposures for high-density patterning.
Solution Approach 2:
The hardmask photosensitive composition is applied once in advance before the first exposure, establishing a permanent protective layer that will serve through all subsequent exposure and development cycles. This preliminary action eliminates the need for repeated hardmask application, thereby increasing productivity without sacrificing manufacturing precision.
3Manufacturing precision
If traditional bright field process is used with multiple exposures, then manufacturing precision is improved, but device complexity increases because a hardmask must be reapplied to the substrate before the second exposure-development-etching process
Solution Approach 1:
The patent combines the hardmask and photosensitive compositions into a single integrated layer. This merged layer remains on the substrate throughout multiple exposure cycles, eliminating the need to reapply hardmask between exposures. The integration maintains accurate pattern transfer while reducing the number of discrete process steps and associated complexity.
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 enables the creation of dense microelectronic structures like vias and trenches without the reapplication of hardmask layers or dry-etching, reducing processing time and cost while maintaining pattern integrity.
Implementation Method 1
baking said hardmask composition so as to thermally crosslink said hardmask composition and yield a hardmask layer
Implementation Method 2
exposing said first imaging layer to activating radiation to yield exposed portions in said first imaging layer
Data Source
Figure 1(a)~1(c)
Figure 1(d)~1(f)
Figure 1(g)~1(i)
AI summary
This invention provides methods of creating via or trench structures on a developer- soluble hardmask layer using a multiple exposure-development process. The hardmask layer is patterned while the imaging layer is developed. After the imaging layer is stripped using organic solvents, the same hardmask can be further patterned using subsequent exposure-development processes. Eventually, the pattern can be transferred to the substrate using an etching process.