Dummy Gate Replacement for Metal Gate Defect Prevention
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Solution Overview
Problem
The replacement metal gate (RMG) process in semiconductor manufacturing faces challenges in preventing defects during the transition from polysilicon to metal gate electrodes, particularly due to high-temperature processes and material resistance issues, which affect the operation speed and reliability of semiconductor devices.
Innovation Solution
A method involving the formation of dummy gate structures, spacers, interlayer insulating layers, protective insulating layers, and liner layers on a semiconductor substrate to protect non-patterning regions, allowing for the removal of polysilicon gate electrodes and the subsequent formation of metal gate electrodes without defects, ensuring a smooth transition and maintaining substrate integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If polysilicon gate electrode is used, then durability at high temperature is improved, but resistance value is high resulting in low operation speed
Solution Approach 1:
The patent applies preliminary action by forming a dummy gate structure with dummy gate electrode and dummy gate insulating layer before the actual gate electrode formation. This dummy structure serves as a placeholder that protects the underlying semiconductor substrate during high-temperature processes, and is later removed to allow metal gate electrode formation, thus enabling both high-temperature durability and low resistance operation speed
2Speed
If replacement metal gate process is performed to replace polysilicon with metal gate electrode, then operation speed is improved, but defects may occur on semiconductor substrate
Solution Approach 1:
The patent applies beforehand cushioning by forming a protective insulating layer on the semiconductor substrate before removing the dummy gate structure. This protective layer acts as a cushion that prevents defects on the substrate during the dummy gate removal process, ensuring reliable metal gate electrode formation while maintaining high operation speed
3Speed
If dummy gate structures are formed and then removed during RMG process, then metal gate electrode formation is enabled, but complex manufacturing steps are added
Solution Approach 1:
The patent applies universality by designing the dummy gate structure to serve multiple functions: it acts as a placeholder during high-temperature processes, provides protection to the substrate, and serves as a template for subsequent metal gate electrode formation. This multi-functionality reduces the need for separate protective structures, thereby managing manufacturing complexity while achieving high operation speed
Data Source
AI summary
A method of manufacturing a semiconductor device includes forming dummy gate structures including a dummy gate insulating layer and dummy gate electrodes, on a first region of a semiconductor substrate, the first region including a patterning region, forming spacers on two side walls of each of the dummy gate structures, forming an interlayer insulating layer on the semiconductor substrate and the dummy gate structures, forming a protective insulating layer on a second region of the semiconductor substrate, the second region including a non-patterning region, forming a liner layer on the protective insulating layer, planarizing the interlayer insulating layer by using the liner layer as an etching mask to expose top surfaces of the dummy gate structures, forming openings by removing the dummy gate structures to expose the semiconductor substrate between the spacers, and forming gate structures including a gate insulating layer and metal gate electrodes, in the openings.