Tilted Etch Process for Narrow Semiconductor Openings
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Solution Overview
Problem
The scaling down of semiconductor devices poses challenges in achieving improved quality, yield, performance, and reliability while reducing complexity, particularly in forming narrower openings which require additional photolithography processes.
Innovation Solution
A method involving a tilted etch process using second hard mask layers as pattern guides to form first and second openings on a semiconductor device, reducing the need for additional photolithography and allowing narrower openings to be formed with wider hard mask openings, thereby simplifying the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If additional photolithography processes are used to form narrower openings, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces a tilted etch process that etches at an angle (e.g., 45 degrees) relative to the substrate surface, adding a dimensional aspect to the opening formation. This allows narrower openings to be created by controlling the tilt angle and etch depth rather than requiring multiple photolithography steps, thus improving precision while reducing process complexity
Solution Approach 2:
The patent changes the etch process parameters by introducing a tilted incidence angle and controlling the etch depth to a specific fraction of the hard mask layer thickness. By adjusting these parameters (tilt angle, etch depth ratio), the opening width is precisely controlled without needing additional photolithography processes, resolving the contradiction between precision and complexity
2Manufacturing precision
If additional photolithography processes are used to form narrower openings, then manufacturing precision is improved, but loss of time increases
Solution Approach 1:
By utilizing the tilted etch dimension, the patent achieves precise opening width control in a single etch process rather than requiring multiple sequential photolithography and etch cycles, thereby reducing total fabrication time while maintaining or improving precision
Solution Approach 2:
The tilted etch process is designed to automatically self-limit at a depth that corresponds to the desired opening width based on the hard mask layer thickness and tilt angle. This preliminary determination of etch parameters eliminates the need for iterative adjustments and additional processing steps, saving time
3Ease of manufacture
If conventional etch processes are used, then ease of manufacture is maintained, but manufacturing precision deteriorates
Solution Approach 1:
The patent modifies the conventional etch process by changing key parameters: introducing a tilted incidence angle (e.g., 45 degrees) and controlling etch depth to a specific ratio of the hard mask layer thickness. These parameter changes enable precise opening width control while maintaining a relatively simple single-step process, thus improving precision without sacrificing ease of manufacture
Solution Approach 2:
The tilted etch process is designed to self-limit at the appropriate depth and opening width based on the geometry of the hard mask layer and the etch parameters. The process automatically achieves the desired precision without requiring complex real-time control or additional correction steps, maintaining ease of manufacture while improving precision
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 improves the yield of semiconductor devices by reducing fabrication complexity and alleviating the requirements for photolithography, enabling the formation of narrower openings without additional processing steps.
Implementation Method 1
performing a first tilted etch process on the first hard mask layer to form first openings along the first hard mask layer and adjacent to first sides of the second hard mask layers, and performing a second tilted etch process on the first hard mask layer to form second openings along the first hard mask layer and adjacent to second sides of the second hard mask layers
Data Source
AI summary
The present application discloses a method for fabricating a semiconductor device using a tilted etch process. The method includes forming an etching stop layer on a substrate, forming a target layer on the etching stop layer, forming a first hard mask layer on the target layer, forming second hard mask layers on the first hard mask layer, performing a first tilted etch process on the first hard mask layer to form first openings along the first hard mask layer and adjacent to first sides of the second hard mask layers, and performing a second tilted etch process on the first hard mask layer to form second openings along the first hard mask layer and adjacent to second sides of the second hard mask layers.