Lattice-Patterned Reticle for High-Density DRAM Capacitors
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Solution Overview
Problem
Current methods for patterning semiconductor constructions, such as imprint lithography, face challenges in achieving high packing density of features, particularly in forming container capacitors for dynamic random access memory (DRAM) devices, where the resolution and spacing of patterns are limited by optical lithography techniques.
Innovation Solution
A method involving the formation of a reticle with a radiation-imageable layer and a lattice pattern, where the lattice is used as a mask for etching pillars into a substrate, and subsequent narrowing of gaps between pillars with a second material to enhance packing density, allowing for high-density formation of container capacitors in semiconductor substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If optical lithography is used for patterning, then the process is simple and well-established, but the feature width and packing density are limited
Solution Approach 1:
The patterning process is divided into multiple steps: first forming a lattice pattern with initial pillars, then adding a second material to narrow gaps, and finally forming container openings. This segmentation allows achieving higher precision than single-step optical lithography by breaking down the complex patterning into manageable stages, each with controlled precision requirements
Solution Approach 2:
The lattice pattern and pillars are formed in advance before the final container capacitor structure is created. This preliminary patterning establishes the spatial framework that guides subsequent processing steps, enabling higher final precision by preparing the structure incrementally rather than attempting to form the final pattern in a single step
2Productivity
If feature spacing is reduced to increase packing density, then integration level increases, but manufacturing precision requirements become more demanding
Solution Approach 1:
The patent transitions from two-dimensional planar patterning to three-dimensional vertical structures by forming pillars that extend through the substrate. This dimensional change allows features to be packed more densely in the plane while maintaining adequate spacing through vertical separation, effectively increasing packing density without proportionally increasing spacing control difficulty
Solution Approach 2:
The second material is introduced as an intermediary substance that selectively fills gaps between pillars. This intermediary material enables precise control of final feature spacing by its deposition thickness and selectivity, allowing narrow gap control that would be difficult to achieve with direct lithographic patterning alone
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 formation of high-density container capacitors with improved feature resolution and spacing, enhancing the integration levels of DRAM arrays by utilizing the reticle to pattern semiconductor constructions effectively.
Implementation Method 1
A radiation-imageable layer is formed over the first material. A lattice pattern is formed within the radiation-imageable layer
Implementation Method 2
The lattice-patterned radiation-imageable material is utilized as a mask while the first material is subjected to an etch which transfers the lattice pattern into the first material
Data Source
AI summary
The invention includes methods of forming reticles configured for imprint lithography, methods of forming capacitor container openings, and methods in which capacitor container openings are incorporated into DRAM arrays. An exemplary method of forming a reticle includes formation of a radiation-imageable layer over a material. A lattice pattern is then formed within the radiation-imageable layer, with the lattice pattern defining a plurality of islands of the radiation-imageable layer. The lattice-patterned radiation-imageable layer is utilized as a mask while subjecting the material under the lattice-patterned layer to an etch which transfers the lattice pattern into the material. The etch forms a plurality of pillars which extend only partially into the material, with the pillars being spaced from one another by gaps. The gaps are subsequently narrowed with a second material which only partially fills the gaps.