Semiconductor Structure Ion Implantation Stop Layer Pit Formation
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Solution Overview
Problem
The gate-last process for forming high-K metal gate (HKMG) semiconductor structures often results in degraded insulation performance due to poor denseness of the dielectric layer between transistors, leading to pit formation and reduced semiconductor structure performance.
Innovation Solution
A method involving ion implantation to create stop layers with controlled removal rates during planarization processes, ensuring the dielectric layer's integrity and preventing pit formation by using first and second stop layers with specific thickness and implantation doses to protect the dielectric layer between dummy gates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the dielectric layer is removed on the top of the dummy gate structure to form the isolation dielectric layer, then the metal gate can be formed, but the insulation performance of the isolation dielectric layer is degraded and pits are formed
Solution Approach 1:
A stop layer is formed in the dielectric layer before the planarization process. This stop layer acts as a protective barrier that prevents the planarization process from removing the dielectric layer on top of the dummy gate structure, thereby preventing pit formation and maintaining insulation performance while still allowing metal gate formation to proceed
Solution Approach 2:
The stop layer is specifically designed to resist the planarization process. By having different removal rates between the stop layer and the dielectric layer, the stop layer counteracts the harmful effect of the planarization process on the dielectric layer's insulation performance, preventing pit formation while allowing the process to continue
2Productivity
If the dielectric layer has poor denseness between transistors, then the fabrication process can proceed, but insulation performance is degraded and semiconductor structure performance is reduced
Solution Approach 1:
The stop layer is formed in advance within the dielectric layer to provide a protective function. This preliminary structure ensures that even if the dielectric layer has poor denseness, the stop layer will prevent pit formation during planarization, maintaining insulation performance while allowing the fabrication process to continue without interruption
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 enhances the insulation performance of the dielectric layer, preventing pit formation and improving the overall performance of the semiconductor structure by maintaining the dielectric layer's integrity and facilitating smooth metal gate formation.
Implementation Method 1
performing a first ion implantation process on the dielectric layer to form a first stop layer in the dielectric layer
Data Source
AI summary
A semiconductor structure and a method for fabricating the semiconductor structure are provided. The method includes providing a plurality of dummy gates on a substrate, a capping layer on each dummy gate, and a dielectric layer over the substrate, wherein the dielectric layer has a top surface above each dummy gate. The method also includes performing a first ion implantation process on the dielectric layer to form a first stop layer in the dielectric layer. A top surface of the first stop layer is above or coplanar with a top surface of each dummy gate. Further, the method includes performing a first planarization process on the capping layer and the dielectric layer to expose the top surface of each dummy gate. A removal rate of the first stop layer is smaller than a removal rate of the dielectric layer when performing the first planarization process.