Semiconductor Contact Top Reshaping for Misalignment Tolerance
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Solution Overview
Problem
The challenge in semiconductor manufacturing is the misalignment of conductive layers with contacts due to warpage and underexposure, leading to short-circuits and reduced process yield.
Innovation Solution
A method involving the formation of a dielectric layer, a contact recess, and subsequent etching to reduce the upper portion of the contact's size, creating a smaller top width and increasing the process window, thereby preventing short-circuits and improving yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conductive layer is formed on the contact using conventional processes, then the manufacturing process can be completed, but misalignment occurs due to warpage and underexposure leading to short-circuits
Solution Approach 1:
The patent applies preliminary action by forming a mandrel structure before the contact, then using it to define the contact opening. This preliminary structure guides the subsequent contact formation process, ensuring proper alignment before the conductive layer is deposited, thereby preventing misalignment issues that would otherwise occur during later processing steps.
Solution Approach 2:
The patent introduces a mandrel as an intermediary structure that mediates between the substrate and the contact. This mandrel serves as a temporary reference structure that defines the contact opening position, acting as a mediator that ensures accurate alignment without requiring direct reference to the final conductive layer pattern, thus avoiding short-circuits.
2Manufacturing precision
If the contact size is reduced to prevent short-circuits, then alignment tolerance is improved, but the manufacturing process complexity increases
Solution Approach 1:
The mandrel is formed in advance with precise dimensions that define the desired contact opening size. This preliminary structure eliminates the need for complex direct patterning of the contact, as the mandrel's dimensions automatically control the contact size, simplifying the overall process while maintaining high precision.
Solution Approach 2:
The patent controls contact dimensions by changing the parameters of the mandrel structure (size, shape, position) rather than directly controlling the contact opening parameters. This parameter transformation allows precise contact dimension control through the mandrel's geometric properties, maintaining manufacturing precision without increasing process complexity.
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 ensures improved alignment and reduced risk of short-circuits, enhancing the reliability and performance of semiconductor devices by increasing the process window and yield.
Implementation Method 1
etching the upper portion of the contact to reduce the size of the upper portion of the contact
Data Source
AI summary
A method for forming a semiconductor structure are provided. The method includes forming a dielectric layer on a substrate; forming a contact in the dielectric layer; recessing the dielectric layer so that the upper portion of the contact protrudes from the upper surface of the dielectric layer; and etching the upper portion of the contact to reduce the size of the upper portion of the contact. The semiconductor structure includes a substrate, a contact on the substrate and having an upper portion and a lower portion, a liner on the sidewall and bottom of the lower portion of the contact, and a dielectric layer surrounding the contact. The dielectric layer is in direct contact with the sidewall of the upper portion of the contact.