Dummy Gate Structure for CMP Dishing-Free Metal Gate Formation
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Solution Overview
Problem
The chemical mechanical polishing (CMP) process in semiconductor manufacturing can cause dishing in the insulation layer over semiconductor components, leading to residual metal material retention and subsequent pollution during the replacement of a dummy gate with a metal gate.
Innovation Solution
A dummy gate structure is positioned above a second element in the substrate, comprising patterns on the insulation pattern and element isolation structure, preventing dishing during CMP and ensuring the metal material does not retain in the dished areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a CMP process is used to planarize the insulation layer, then the top surface of the dummy gate can be exposed, but dishing occurs in the insulation layer above semiconductor components
Solution Approach 1:
A dummy gate structure is formed in advance in the second active region where a metal gate will subsequently be formed. This preliminary structure serves as a support during the CMP process, preventing dishing in the insulation layer before the actual metal gate formation occurs.
Solution Approach 2:
The dummy gate structure acts as an intermediary element during the CMP process. It provides mechanical support to the insulation layer in the second active region, preventing direct contact between the CMP polishing pad and the insulation layer, thereby eliminating dishing while still allowing planarization elsewhere.
2Ease of manufacture
If the dummy gate is removed and metal material is filled to replace it, then the metal gate can be formed, but metal material retains in dishing areas and causes pollution
Solution Approach 1:
The dummy gate structure is formed in advance not only to reserve space for the metal gate but also to prevent dishing during CMP. This preliminary action ensures that when metal material is subsequently filled, there are no dishing areas to retain the metal material, thus preventing pollution.
Solution Approach 2:
The dummy gate structure provides preliminary anti-action against the formation of dishing during CMP. By maintaining structural integrity in the second active region during planarization, it prevents the creation of凹陷 areas that would later trap metal material and cause contamination.
3Manufacturing precision
If the insulation layer is planarized over the entire substrate, then uniform thickness is achieved, but dishing occurs in areas without semiconductor components
Solution Approach 1:
The dummy gate structure is selectively formed only in the second active region where a metal gate is to be formed, providing localized support during CMP. This local quality approach prevents dishing specifically in the area needing protection while allowing planarization to proceed uniformly across the entire substrate.
Solution Approach 2:
The dummy gate is formed in advance in the specific region that requires protection during planarization. This preliminary local structure ensures that when CMP is applied across the entire substrate, only the areas with dummy gates are protected from dishing, achieving both uniformity and shape integrity.
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
Prevents dishing in the insulation layer, thereby avoiding metal material retention and subsequent pollution by peeling, enhancing the reliability and cleanliness of the semiconductor manufacturing process.
Implementation Method 1
a planarization process (e.g., a chemical mechanical polishing (CMP) process) is usually adopted to remove excess insulation materials
Data Source
AI summary
Provided are a semiconductor device and a method for forming the same. The semiconductor device includes a substrate including first and second active regions defined by an element isolation structure, a first element in the first active region and including a gate structure on the substrate, a second element in the second active region and including an insulation pattern in the substrate and including a first portion and a second portion surrounding the first portion, and a dummy gate structure in the second active region and including first and second patterns respectively on the first and second portions and a third pattern on the device isolation structure. The second portion and the element isolation structure define a region where a first doped region of the second element is formed. The second portion and the first portion define a region where a second doped region of the second element is formed.