Semiconductor Patterning via Solubility-Shifting Agent Stitching
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Solution Overview
Problem
Conventional microfabrication techniques for semiconductor devices require multiple photolithography steps to achieve precise patterning, especially for large devices, which can lead to alignment issues and reduced device density.
Innovation Solution
A method involving the use of a solubility-shifting agent to stitch together non-contiguous trenches on a substrate, achieved by exposing a resist layer to multiple patterns of actinic radiation, developing to form relief patterns, coating with the solubility-shifting agent, and diffusing it into the resist layer to facilitate alignment and merging of trenches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple photolithography exposures are used to pattern large semiconductor devices, then the device area that can be patterned is increased, but alignment accuracy between exposed regions deteriorates
Solution Approach 1:
The patent divides the large device area into multiple smaller exposed regions (first exposed region, second exposed region, etc.) that are exposed separately through multiple photolithography steps. Each region is patterned independently with high precision, then the patterns are stitched together to form the complete large-area device structure.
Solution Approach 2:
The patent introduces an intermediary material or process step between the multiple exposed regions to facilitate accurate stitching. This intermediary element serves as a reference or bridge that enables precise alignment and merging of patterns from different exposed regions, thereby maintaining manufacturing precision across the entire large device area.
2Quantity of substance
If multiple separate lithography exposures are used to create line cuts, then the device density can be maintained, but the alignment and merging of features between exposures becomes more difficult
Solution Approach 1:
The patent merges multiple separately exposed patterns into a unified continuous structure through precise stitching. The first exposed region and second exposed region are aligned and combined to form seamless line cuts and continuous patterns, reducing stitching complexity while maintaining high device density.
Solution Approach 2:
The patent performs preliminary actions such as preparing alignment marks, pre-coating resist layers, or pre-defining exposure parameters before the actual multiple exposures. These preliminary steps establish reference frameworks that simplify the subsequent stitching process and reduce the complexity of merging features between exposures.
3Area of stationary object
If conventional photolithography is used for large devices requiring multiple exposures, then the complete device can be patterned, but overlay accuracy between exposures is reduced
Solution Approach 1:
The patent implements feedback mechanisms through alignment marks and measurement systems that monitor and adjust the position of each exposed region relative to previous exposures. This real-time feedback enables correction of alignment deviations and maintains high overlay accuracy across the complete large device area throughout the multiple exposure process.
Solution Approach 2:
The patent replaces purely mechanical alignment methods with optical or chemical alignment systems. Optical alignment marks and chemical solubility-shifting agents provide more precise and stable reference systems for overlay accuracy compared to traditional mechanical positioning, enabling better alignment precision across multiple exposures of the complete device.
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 creation of precise, contiguous patterns on semiconductor substrates with improved overlay accuracy and density, enabling the fabrication of large semiconductor dies without sacrificing performance.
Implementation Method 1
diffusing the solubility-shifting agent a predetermined distance into the resist layer
Implementation Method 2
exposing the resist layer to a first pattern of actinic radiation to form a first latent image in the resist layer
Data Source
AI summary
A method of patterning a substrate is described. The method includes the steps of providing a resist layer on the substrate, exposing the resist later to a first pattern of actinic radiation to form a latent imagine in the resist layer, and exposing the resist layer to a second pattern of actinic radiation to form a second latent imagine in the resist later, wherein the first latent image and the second latent image are adjacent. The method further includes developing the resist layer to form a relief patten that includes a first set of trenches corresponding to the first pattern of actinic radiation and a second set of trenches corresponding to the second pattern of actinic radiation, wherein the first set of trenches and the second set of trenches are not contiguous. Next, the method includes coating the relief pattern with a solubility-shifting agent, followed by diffusing the solubility-shifting agent a predetermined distance into the resist layer, wherein the solubility-shifted region of the resist borders the first relied pattern, and lastly developing the resist layer to stitch together the first set of trenches and the second set of trenches.