Contact Hole Mandrel Formation for Deep DRAM Etching
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Solution Overview
Problem
The challenge in semiconductor manufacturing is creating deep contact holes with a high depth-width ratio, as overlarge holes can cause short circuits and over-small holes lead to insufficient etching, especially with the increasing integration level and shrinking dimensions in DRAM technology.
Innovation Solution
A method for manufacturing contact holes involves forming a mask layer, etching the first oxide layer to expose the target contact area, depositing and removing insulation and oxide layers to precisely define the contact hole dimensions, and etching further to expose the zeroth layer contact, thereby avoiding both short circuits and insufficient etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact hole size is increased to ensure sufficient etching, then the etching reliability is improved, but the risk of short circuit increases
Solution Approach 1:
The patent applies preliminary action by forming a mandrel structure before contact hole etching. The mandrel is created by depositing a first insulation layer with a first opening, then forming a second insulation layer with a second opening that defines the contact hole pattern. This preliminary structure guides the subsequent etching process to achieve precise contact hole dimensions without over-etching or under-etching, thereby preventing both short circuits and insufficient etching.
Solution Approach 2:
The patent uses an intermediary approach by introducing a mandrel structure composed of insulation layers as a mediator between the patterning step and the contact hole etching. The mandrel acts as a temporary structure that defines the contact hole geometry during fabrication, allowing precise control of contact hole size and shape. After serving its guiding function, the mandrel is removed, leaving cleanly defined contact holes with appropriate dimensions that avoid both short circuits and etching deficiencies.
2Object-affected harmful factors
If the contact hole size is decreased to prevent short circuits, then the short circuit risk is reduced, but the etching completeness deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-forming a mandrel structure that precisely defines the contact hole dimensions before etching. The mandrel's second opening is configured to define the contact hole pattern with appropriate size and shape, ensuring that the subsequent etching process achieves complete and accurate contact hole formation without under-etching, while the controlled dimensions prevent short circuits.
Solution Approach 2:
The patent introduces a mandrel structure as an intermediary element that mediates between the patterning requirements and etching process. This intermediate structure provides a physical template that ensures complete etching coverage while maintaining precise dimensional control, thereby simultaneously achieving etching completeness and preventing short circuits through properly sized contact holes.
3Productivity
If the integration level is increased to improve device performance, then the device performance is improved, but the manufacturing difficulty increases
Solution Approach 1:
The patent applies segmentation by dividing the contact hole formation process into distinct stages: forming the first insulation layer with a first opening, depositing the second insulation layer with a second opening that defines the contact hole pattern, and then performing the etching. This segmented approach allows each step to be optimized independently, managing the complexity of high integration level manufacturing while achieving the required precision for advanced device performance.
Solution Approach 2:
The patent uses preliminary action to prepare the mandrel structure in advance before the critical contact hole etching step. By pre-forming the insulation layers and openings that define the contact hole geometry, the complex requirements of high integration level manufacturing are managed through careful preliminary structuring, reducing the difficulty of the subsequent etching process while maintaining the precision needed for advanced device performance.
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 method ensures accurate and reliable contact hole formation, reducing the risk of short circuits and insufficient etching, and simplifies the semiconductor manufacturing process by enlarging then shrinking the contact hole dimensions using insulation and oxide layers.
Implementation Method 1
the first oxide layer is etched according to the pattern of the target contact hole, so as to expose a portion, corresponding to the target contact hole, of an upper end face of the contact layer
Implementation Method 2
a second insulation layer is deposited on an etched surface, and a second oxide layer is deposited on the second insulation layer
Data Source
AI summary
Disclosed is a method for manufacturing a contact hole, a semiconductor structure and electronic equipment. The method includes: forming a mask layer on an upper end face of a first oxide layer of the semiconductor structure, and exposing a pattern of a target contact hole on the mask layer; exposing a portion, corresponding to a target contact hole, of an upper end face of a contact layer and a portion, corresponding to the target contact hole, of an upper end face of an upper layer structure; depositing a second insulation layer on an etched surface, and depositing a second oxide layer on the second insulation layer; and removing portions, above the upper end face of the first oxide layer, of the second insulation layer and the second oxide layer, and removing a part of the contact layer, and exposing an upper end face of a zeroth layer contact.