Contact Plug Sealing in High-Aspect-Ratio Backside Holes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor manufacturing, the formation of metal contact plugs on the backside of wafers with high aspect ratio contact holes often results in voids and seams due to high growth rates on metal glue layers, leading to high electrical resistance and potential damage in subsequent processes.
Innovation Solution
The method involves bottom-up metal growth with post-treatment to form contact plugs, using a dielectric liner layer and silicide formation to prevent voids and seams, and subsequent dopant implantation to enhance metal sealing and prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal layer is grown from sidewall of contact hole with metal glue layer, then adhesion between metal contact plug and substrate is enhanced, but voids and seams are formed in metal contact plug due to high growth rate
Solution Approach 1:
A dielectric liner layer is introduced as an intermediary between the metal glue layer and the metal contact plug. This liner layer acts as a barrier that prevents direct high-rate growth of the metal contact plug on the metal glue layer, thereby eliminating voids and seams while preserving the adhesion benefits of the metal glue layer through controlled interaction.
2Reliability
If contact hole has large aspect ratio to penetrate thick backside substrate, then electrical connection through substrate is achieved, but metal layer seals contact hole before complete filling due to bottom-up growth limitation
Solution Approach 1:
The dielectric liner layer serves as a mediator that enables complete filling of high aspect ratio contact holes by controlling the growth interface. It prevents premature sealing by the metal layer and facilitates uniform bottom-up growth throughout the entire depth of the contact hole, ensuring complete filling even in thick substrates.
Solution Approach 2:
The growth rate parameters are controlled by introducing the dielectric liner layer, which modifies the interface properties between the metal layer and underlying structures. This parameter change enables sustained growth through high aspect ratio contact holes without premature sealing, achieving complete filling while maintaining electrical connection reliability.
3Reliability
If dopants with atomic size greater than Si are implanted into substrate around contact plug, then metal sealing is enhanced and structural degradation is prevented, but manufacturing process complexity increases
Solution Approach 1:
Dopants with atomic size greater than silicon are implanted into the substrate in advance, before the metal contact plug formation process. This preliminary action creates a dopant-enriched region that enhances metal sealing and prevents structural degradation during subsequent processing, thereby improving reliability without adding complexity to the main contact formation 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 achieves low electrical resistance and prevents structural degradation of contact plugs, ensuring reliable electrical connections and maintaining structural integrity through the manufacturing process.
Implementation Method 1
a metal layer is then deposited to fill the contact hole
Implementation Method 2
a first implantation process is performed on the substrate, so as to implant dopants having an atomic size greater than that of Si into the substrate
Data Source
AI summary
A method is provided for forming a metal contact plug. In one step, a substrate, which is an Si substrate or an SiO2 substrate, is etched to form a contact hole. In one step, a dielectric liner layer is formed on a sidewall of the contact hole. In one step, the metal contact plug that is in contact with the dielectric liner layer is formed in the contact hole. In one step, an implantation process is performed on the substrate, so as to implant dopants having an atomic size greater than that of Si into the substrate.