Sidewall Image Templates for Directed Self-Assembly Pitch Control
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Solution Overview
Problem
Existing lithography techniques, including optical lithography and directed self-assembly (DSA), face challenges in patterning structures with varying pitches and dimensions, which are essential for advanced semiconductor device applications.
Innovation Solution
The use of sidewall image templates and spacers in conjunction with directed self-assembly materials allows for the formation of mask structures that define multiple pitches and critical dimensions, enabling the patterning of semiconductor devices with precise control over feature pitches and dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If directed self-assembly (DSA) is used to pattern structures, then large areas of straight line/space patterns with constant pitch can be created, but it is difficult to pattern lines of varying pitch and/or dimensions
Solution Approach 1:
The patent applies local quality by using sidewall image templates with varying dimensions and spacings to create localized pitch variations in the final pattern. Different regions of the template have different element spacings, which directly control the pitch of features in corresponding regions of the patterned structure, enabling both high precision and pitch variability.
Solution Approach 2:
The template is segmented into multiple elements with different spacings and dimensions, allowing different regions to generate different pitches. This segmentation enables the creation of complex patterns with varying pitches by combining multiple template elements with distinct geometric parameters.
2Productivity
If optical lithography is used for high-throughput processing, then processing speed is improved, but the patterning pitch is limited
Solution Approach 1:
The patent uses preliminary action by first forming a template with desired pitch characteristics using optical lithography, then using this template to guide the self-assembly process that creates the final fine-pitch pattern. This preliminary template formation enables high-throughput processing while achieving smaller final pitches through the self-assembly multiplication effect.
Solution Approach 2:
The template acts as an intermediary between the optical lithography process and the final fine-pitch pattern. It translates the relatively coarse lithography features into a guide pattern that directs polymer self-assembly to create much finer pitch features, effectively bridging the gap between lithography capabilities and target pitch requirements.
3Manufacturing precision
If template elements are made smaller to reduce pitch, then feature dimension control is improved, but template manufacturing complexity increases
Solution Approach 1:
The patent applies self-service by using the template's own geometric features (sidewalls, spacings) to automatically define the pitch and dimensions of the final pattern through self-assembly. The template structure itself serves as the instruction set for pattern formation, eliminating the need for complex alignment and positioning systems, thereby reducing manufacturing complexity despite small feature sizes.
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 facilitates the fabrication of semiconductor devices with multiple pitches and critical dimensions, enhancing thermal stability and enabling the creation of complex patterns, such as finFET devices and gate electrodes, while overcoming limitations of traditional lithography methods.
Implementation Method 1
The polymeric self-assembly material contains two (or more) chemical components that have carefully controlled size. These so-called A and B components can be bonded together into polymer chains known as diblocks. Immediately after coating, the A and B components are relatively disordered, however, these components (A, B) can be induced to separate into distinct phases and thereby form features with a characteristic pitch
Implementation Method 2
forming spacers on sidewalls of the plurality of elements
Data Source
AI summary
In one example, a method includes forming a template having a plurality of elements above a process layer and forming spacers on sidewalls of the plurality of elements. Portions of the process layer are exposed between adjacent spacers. At least one of the plurality of elements is removed. A mask structure is formed from a directed self-assembly material over the exposed portions. The process layer is patterned using at least the mask structure as an etch mask.