Dual DSA Patterning for Defect Reduction in Semiconductor Fabrication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Directed self-assembly (DSA) techniques in semiconductor microfabrication face challenges with high defectivity, resulting in approximately one defect per 25 million patterns, which hinders the creation of precise features like memory arrays and contacts.
Innovation Solution
Implementing a dual DSA patterning process where a first self-assembling composition layer forms a relief pattern that is then used to create a mask for etching, followed by a second self-assembling composition layer forming a complementary pattern to compensate for defects, thereby reducing the probability of defects aligning and preventing etching errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional DSA patterning is used to create nanometer-sized structures, then pattern dimensions can be shrunk to meet design specifications, but defects occur at a rate of approximately one in 25 million features
Solution Approach 1:
The patent divides the single DSA patterning process into multiple sequential steps, where each step creates a portion of the final pattern. By segmenting the process into multiple stages with intermediate layers, the patent enables defect correction between steps while maintaining the ability to achieve fine pattern dimensions through cumulative self-assembly actions.
Solution Approach 2:
The patent employs preliminary patterning steps that create template structures before the final DSA pattern is formed. These preliminary structures serve as guides or masks that direct subsequent self-assembly processes, allowing defects in later steps to be corrected by reference to the pre-established pattern framework.
2Reliability
If multiple DSA patterning steps are executed to reduce defect probability, then defect rate decreases to approximately one in 6.25×10^14, but process complexity increases
Solution Approach 1:
The patent combines multiple DSA patterning steps with conventional lithographic techniques, merging self-assembly processes with established manufacturing methods. By integrating DSA into a broader process flow that includes lithography, etching, and deposition steps, the patent reduces the relative complexity impact of multiple DSA steps while achieving superior defect reduction.
Solution Approach 2:
The patent introduces intermediary layers and structures that facilitate transition between different patterning steps. These intermediary elements act as buffers or bridges, allowing the patent to sequence multiple DSA steps without directly exposing each other's defects, thereby reducing overall process complexity while maintaining high reliability.
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 significantly reduces defect occurrence from one in 25 million to one in 6.25×10^14, enabling defect-less or low-defect patterns, thereby increasing the yield of functional semiconductor devices and eliminating the need for scanner exposure, making semiconductor fabrication more economical.
Implementation Method 1
Activation of phase separation is typically executed via addition of heat energy which causes block copolymer separation on nanoscale dimensions based on various polymer parameters
Implementation Method 2
A first self-assembling composition layer of block copolymers is deposited on the hardmask layer. Phase separation of the first self-assembling composition layer is activated such that a first plurality of discrete structures is formed
Data Source
AI summary
Techniques herein enable executing directed self-assembly of block copolymer patterning processes that result in patterns having no defects or a negligibly low occurrence of defects to have a high yield of functional patterns and devices. Methods include executing a same DSA patterning sequence two or more times such that any defects in from a phase-separated first block copolymer film are corrected with a phase-separated second block copolymer film as any defect in the second block copolymer film would only temporarily cover a feature already created and/or transferred from first block copolymer film.