Semiconductor Contact Gap Filling via Ion Implantation
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Solution Overview
Problem
The challenge in semiconductor device fabrication is depositing conductive materials into features with high aspect ratios, such as contact holes, without forming undesirable defects like seams and voids, which affect the electrical properties of the contacts.
Innovation Solution
A method involving the formation of a first conductive material with a top portion and a bottom portion, where ion implantation is used to differentiate the ion density between the two, followed by etching to remove the top portion and filling the opening with a second conductive material, ensuring proper sealing and filling from bottom to top.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conductive material is deposited into high aspect ratio features, then contact formation is achieved, but seams and voids are generated
Solution Approach 1:
The conductive material deposition is divided into multiple sequential steps: first depositing a bottom portion, then performing ion implantation, removing the top portion, and finally depositing a second conductive material. This segmentation allows each step to be optimized independently, preventing seam and void formation that would occur in a single deposition step.
Solution Approach 2:
Ion implantation is performed on the first conductive material before the final deposition step to modify its properties. This preliminary action creates a foundation that prevents seam formation during subsequent deposition, addressing the reliability issue before the final contact formation occurs.
2Area of moving object
If feature size decreases, then device density increases, but aspect ratio increases making deposition more difficult
Solution Approach 1:
The deposition process is segmented into multiple controlled steps with ion implantation interspersed, making it feasible to deposit materials into high aspect ratio features that would be impossible to fill with conventional single-step deposition methods.
Solution Approach 2:
Ion implantation changes the physical and chemical parameters of the conductive material, modifying its properties to enable better filling behavior in high aspect ratio features. This parameter change allows deposition processes to succeed where they would normally fail.
3Manufacturing precision
If ion implantation is performed on first conductive material, then seam formation is reduced, but process complexity increases
Solution Approach 1:
Ion implantation is performed as a preliminary action on the first conductive material to prevent seam formation before the final deposition occurs. This preliminary treatment simplifies the overall process by preventing defects that would require additional corrective steps.
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 effectively reduces seam and void formation, enhancing the electrical properties of contacts by precisely controlling the ion implantation and deposition processes, thereby improving the reliability of contact formation in high aspect ratio features.
Implementation Method 1
Ion implantation is performed on the first conductive material. The top portion of the first conductive material is associated with a first ion density, and the bottom portion of the first conductive material is associated with a second ion density smaller than the first ion density.
Data Source
AI summary
Systems and methods are provided for contact formation. A semiconductor structure is provided. The semiconductor structure includes an opening formed by a bottom surface and one or more side surfaces. A first conductive material is formed on the bottom surface and the one or more side surfaces to partially fill the opening, the first conductive material including a top portion and a bottom portion. Ion implantation is formed on the first conductive material, the top portion of the first conductive material being associated with a first ion density, the bottom portion of the first conductive material being associated with a second ion density lower than the first ion density. At least part of the top portion of the first conductive material is removed. A second conductive material is formed to fill the opening.