Kerf Alignment Mark Structure for CMP Dishing Suppression
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Solution Overview
Problem
Semiconductor devices face issues with dishing and film peeling during the manufacturing process, particularly in the kerf area where alignment marks are used, leading to potential defects in lithography and adhesion problems.
Innovation Solution
Incorporating a fine pattern in the kerf area with an interlayer insulating film, which acts as a stopper during chemical mechanical polishing (CMP) to reduce dishing and improve adhesion between layers, thereby stabilizing the alignment marks and preventing film peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemical mechanical polishing (CMP) is performed on the semiconductor substrate, then the surface flatness is improved, but dishing occurs in the kerf area
Solution Approach 1:
The patent applies local quality by providing a stopper structure specifically in the kerf area (non-memory cell regions) rather than uniformly across the entire substrate. The stopper has different properties than the surrounding film layers, creating localized variation that prevents dishing only where needed during CMP processing.
Solution Approach 2:
The stopper structure acts as an intermediary element between the CMP polishing surface and the underlying film layers. It mediates the polishing process by providing a controlled resistance to the polishing head, preventing excessive removal of material and thereby preventing dishing in the kerf area.
2Ease of manufacture
If the kerf area is left without additional structures, then the manufacturing process is simpler, but film peeling occurs during polishing
Solution Approach 1:
The stopper structure is formed in advance during the film stacking process, before the CMP polishing step. This preliminary action ensures that the adhesion reinforcement is already in place to prevent film peeling during the subsequent polishing operation, without requiring additional process steps later.
3Measurement precision
If alignment marks are provided in the kerf area, then lithography alignment is improved, but the marks become unstable due to dishing and film peeling
Solution Approach 1:
The stopper structure provides beforehand cushioning by preventing dishing and film peeling in the kerf area where alignment marks are located. This protective action occurs before any potential damage to the alignment marks, ensuring their stability and maintaining their visibility and precision throughout the manufacturing process.
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 fine pattern effectively reduces dishing and film peeling, enhancing the visibility and stability of alignment marks, thus improving the manufacturing process and reducing defects in semiconductor devices.
Implementation Method 1
acts as a stopper during chemical mechanical polishing (CMP)
Data Source
AI summary
A semiconductor device includes: a semiconductor substrate including a first area and a second area; a plurality of memory cells provided in the first area; a mark provided in the second area and having a first side surface and a second side surface that intersects with the first side surface; and a plurality of patterns provided in the second area and provided on the first side surface and the second side surface.