Semiconductor Contact Holes via Variable Resist Thickness
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Solution Overview
Problem
Current methods for forming contact holes in three-dimensional semiconductor structures require repeated lithography and etching processes, which are inefficient and lack precision in achieving varying depths, leading to increased process complexity and potential inaccuracies.
Innovation Solution
A manufacturing method involving the use of a guide pattern with varying resist film thicknesses, applied using lithography and etching techniques, allows for the formation of contact holes of different depths in a single etching process, reducing the number of processes and enhancing accuracy by controlling resist volume and preventing outflow during reflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If repeated lithography and etching processes are used to form contact holes of different depths, then the depth precision of contact holes is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by forming a guide pattern before the main etching process. This guide pattern serves as a pre-prepared structure that defines the etching depth regions, eliminating the need for multiple sequential lithography and etching steps. The guide pattern is created with specific thickness variations that directly correspond to the desired contact hole depth variations, allowing single-step etching to achieve precise depth control.
Solution Approach 2:
The guide pattern acts as an intermediary element between the lithography process and the etching process. It translates the desired contact hole depth information into a physical structure with varying thickness that the etching process can directly utilize. This intermediary structure enables the etching process to automatically achieve different depths in different regions without requiring complex process sequencing.
2Manufacturing precision
If repeated lithography and etching processes are used to form contact holes of different depths, then the contact hole depth control is improved, but the manufacturing time increases
Solution Approach 1:
The patent merges multiple separate lithography and etching operations into a single integrated process. By combining the depth information for all contact holes into one guide pattern structure, the patent enables all contact holes of different depths to be formed in a single etching step, dramatically reducing the total manufacturing time while maintaining precise depth control.
Solution Approach 2:
The guide pattern is formed in advance with all the depth information encoded in its structure. This preliminary preparation allows the subsequent etching process to proceed in a single step without requiring intermediate measurements or adjustments, thereby reducing manufacturing time while ensuring accurate depth control.
3Ease of manufacture
If uniform resist film thickness is used in lithography, then the lithography process simplicity is improved, but the ability to form contact holes of varying depths is reduced
Solution Approach 1:
The patent applies local quality by creating a guide pattern with spatially varying thickness within the resist film. Different regions of the guide pattern have different thicknesses, which directly correspond to the desired contact hole depths in those regions. This local variation in film thickness is achieved through selective deposition or etching processes that modify the uniform resist film to create the required thickness profile.
Data Source
AI summary
According to one embodiment, a semiconductor device includes a stacked body of N (N is an integer of 2 or more) layers stacked on a semiconductor substrate and openings different in depth surrounded by the stacked body and separated from each other.