Chemical Proximity Resist Patterning for Sub-40nm Alignment
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Solution Overview
Problem
As semiconductor device sizes decrease, accurately aligning contacts and conductive traces becomes increasingly difficult due to the margin of error in photolithography and etching processes, leading to potential device failure or performance degradation, especially at sizes less than 40 nm.
Innovation Solution
The chemical proximity process forms features with wider distal portions and narrower proximal portions by using pools of acidic or basic material below a resist, where the acidity of the resist is altered by diffusion from these pools, affecting solubility and allowing for selective development to create openings with narrower proximal portions without an etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography and etching processes are used to form contacts, then the manufacturing process is well-established and controllable, but the alignment precision deteriorates as device sizes decrease below 40 nm, leading to potential device failure
Solution Approach 1:
The method performs preliminary action by forming mandrels and applying a chemical solution that modifies the resist material properties before the actual patterning step. This preliminary chemical modification creates regions of altered solubility that guide subsequent development, enabling precise contact formation at sub-40nm dimensions without relying solely on conventional photolithography alignment
Solution Approach 2:
The invention changes the chemical parameters of the resist material by introducing a chemical solution that alters the resist's solubility characteristics. This parameter change creates distinct regions within the resist layer that can be selectively removed during development, enabling precise control over contact dimensions and alignment at scales below 40 nm
2Productivity
If device sizes are reduced to increase integration density, then productivity and device capability improve, but the margin of error in photolithography and etching processes increases, making accurate alignment more difficult
Solution Approach 1:
The invention substitutes the mechanical/optical alignment system (photolithography) with a chemical self-alignment mechanism. Instead of relying on mask alignment and etching precision, the method uses chemical diffusion and solubility changes to automatically define contact positions and dimensions, enabling sub-40nm precision without proportionally reducing the process window
3Device complexity
If conventional etching processes are used to form contacts, then the process is simple and fast, but the ability to create features with varying dimensions (wider distal portions and narrower proximal portions) is limited
Solution Approach 1:
The invention applies local quality by creating regions with different chemical properties within the resist layer. The chemical solution modifies specific regions to have altered solubility, enabling the formation of contacts with non-uniform dimensions (wider distal portions and narrower proximal portions) through selective development rather than complex etching sequences
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 process enables the formation of features at sizes less than 40 nm with improved robustness and controllability, allowing for self-alignment and proper connection with conductive traces, reducing the risk of device failure and enhancing performance.
Implementation Method 1
Acid or base of the acidic or basic material is diffused from the pool into proximal portions of the resist
Data Source
AI summary
A method of forming a semiconductor structure comprises forming pools of acidic or basic material in a substrate structure. A resist is formed over the pools of acidic or basic material and the substrate structure. The acidic or basic material is diffused from the pools into portions of the resist proximal to the pools more than into portions of the resist distal to the pools. Then, the resist is exposed to a developer to remove a greater amount of the resist portions proximal to the pools compared to the resist portions distal to the pools to form openings in the resist. The openings have wider portions proximal to the substrate structure and narrower portions distal to the substrate structure. The method may further comprise forming features in the openings of the resist. The features have wider portions proximal to the substrate structure and narrower portions distal to the substrate structure.