Ion-Implanted Hard Mask for ILD Etch Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices continue to reduce minimum feature sizes for increased integration density, the oxide material used in interlayer dielectric layers is susceptible to etching during transistor fabrication, leading to damage of underlying source/drain regions and poor device performance.
Innovation Solution
A hard mask is formed over the interlayer dielectric, followed by an ion implantation and annealing process to improve adhesion, reduce etching rate, and increase density, thereby protecting the ILD and reducing manufacturing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ion implantation and annealing process is performed on the hard mask, then adhesion and density are improved and etching rate is reduced, but the manufacturing process complexity increases
Solution Approach 1:
The ion implantation and annealing process is performed on the hard mask before the oxide etching process to pre-enhance its protective properties. This preliminary treatment ensures the hard mask has optimal adhesion, density, and etching resistance before it is needed to protect the ILD during subsequent etching operations.
Solution Approach 2:
The ion implantation process changes the physical and chemical parameters of the hard mask material by introducing dopant atoms, which modifies its etching rate and adhesion properties. The subsequent annealing process further adjusts these parameters by healing implantation damage and enhancing material density, thereby optimizing the hard mask's protective effectiveness.
2Productivity
If minimum feature sizes are reduced to increase integration density, then more components can be integrated, but the oxide material becomes more susceptible to etching damage
Solution Approach 1:
The hard mask undergoes ion implantation and annealing treatment in advance to create a protective barrier with enhanced resistance to etching. This preliminary anti-action prepares the hard mask to counteract the harmful etching effects that would otherwise damage the ILD during subsequent processing steps.
Solution Approach 2:
The enhanced hard mask serves as an intermediary protective layer between the etching process and the ILD. By positioning and optimizing this intermediate layer, the patent prevents direct harmful interaction between the etchant and the ILD, thereby protecting the underlying structure during etching operations.
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
The ion implantation and annealing process enhances the effectiveness of the hard mask, improving adhesion and reducing etching, resulting in better device performance and reduced damage to the source/drain regions.
Implementation Method 1
performing an ion implantation process to implant dopants into the hard mask, wherein the ion implantation process reduces an etch rate of the hard mask to an oxide etch process
Implementation Method 2
performing a thermal anneal process on the hard mask and the first ILD
Data Source
AI summary
A method includes depositing a first interlayer dielectric (ILD) surrounding a first dummy gate stack and a second dummy gate stack; recessing the first ILD below top surfaces of the first dummy gate stack and the second dummy gate stack; forming a hard mask over the first ILD and between the first dummy gate stack and the second dummy gate stack; performing an ion implantation process to implant dopants into the hard mask, wherein the ion implantation process reduces an etch rate of the hard mask to an oxide etch process; and after performing the ion implantation process, replacing the first dummy gate stack and the second dummy gate stack with a first gate stack and a second gate stack.