Self-Aligned Tungsten Oxide Contact Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for forming contact structures in semiconductor devices face challenges with misalignments and require multiple etching and photolithography processes, which complicate the manufacturing process and reduce alignment margins, especially as design rules approach sub-40 nm scales.
Innovation Solution
A method involving the formation of a contact structure where a tungsten metal layer is filled into a contact hole, followed by a planarization process and an oxidation process under an oxygen atmosphere to grow a tungsten oxide contact, eliminating the need for photolithography and etching processes, thereby improving alignment margins and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography and etching processes are used to form contact structures, then contact structures can be formed, but misalignments occur between contacts and process complexity increases
Solution Approach 1:
The contact structure utilizes self-aligned formation where the second contact is automatically positioned relative to the first contact through the insulation layer, eliminating the need for photolithography alignment. The structure serves itself to define the position of subsequent contacts, achieving perfect alignment without additional alignment processes.
Solution Approach 2:
The invention extracts and removes the photolithography and etching processes from the contact formation sequence. By taking out these complex alignment-dependent processes, the method simplifies the manufacturing flow while eliminating the source of misalignment errors that inherently plague photolithography-based approaches.
2Area of stationary object
If design rules are decreased to sub-40 nm for high integration, then device area is reduced, but alignment margins become insufficient
Solution Approach 1:
The self-aligned contact formation method allows the structure to automatically define the position of the second contact relative to the first contact, ensuring precise positioning even when the available alignment margin is extremely small due to reduced unit cell areas in highly integrated designs.
3Manufacturing precision
If multiple photolithography and etching processes are used to avoid misalignments, then alignment precision improves, but manufacturing time and cost increase
Solution Approach 1:
The invention removes multiple time-consuming photolithography and etching processes from the manufacturing flow. By extracting these redundant processes, the method achieves the same alignment precision with significantly reduced manufacturing time and fewer process steps.
Solution Approach 2:
The method merges the contact formation process into a simpler sequence of deposition and planarization steps, combining multiple separate operations into an integrated process flow that achieves alignment through structural design rather than repeated alignment processes.
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 reduces misalignments, enhances the reliability of semiconductor devices by avoiding barrier layer-related failures, and maintains good electrical characteristics while simplifying the manufacturing process, reducing time and expense.
Implementation Method 1
The metal layer may be planarized by performing a first chemical mechanical polishing (CMP) process using a first slurry composition which has a first concentration of hydrogen peroxide.
Implementation Method 2
the second contact may be grown by performing a plasma treatment or an annealing process under an oxygen atmosphere. an upper portion of the first contact may be oxidized during the annealing process to form a lower portion of the second contact.
Implementation Method 3
the annealing process may be performed at a temperature of about 300° C. to about 600° C. for about 30 seconds to about 15 minutes.
Data Source
AI summary
In a method of forming a contact structure, a first insulation layer including a first contact hole is formed on a substrate. A metal layer including tungsten is formed to fill the first contact hole. A planarization process is performed on the metal layer until the first insulation layer is exposed to form a first contact. A second contact is grown from the first contact. The second contact is formed without performing a photolithography process and an etching process to prevent misalignments.