Semiconductor Device Concave Portion Etching Process
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Solution Overview
Problem
The existing methods for manufacturing semiconductor devices with deep concave portions are complex and costly, requiring prolonged heat treatment and multiple masks, which increases the number of processes and manufacturing costs.
Innovation Solution
A method that forms both a first and second concave portion within a semiconductor substrate using the same etching treatment, with an insulating film covering the concave portions and forming hole portions to reach the conductive regions, reducing the number of processes and treatment time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate processes are used to form deep concave portion and shallow concave portion, then each concave portion can be formed with required precision, but the number of processes and masks increases, raising manufacturing cost
Solution Approach 1:
The patent merges the formation of deep concave portion and shallow concave portion into a single etching process. By using a single mask pattern that defines both concave portions simultaneously, the method eliminates the need for separate etching processes and additional masks, reducing manufacturing complexity while maintaining the precision required for each concave portion's depth and position
Solution Approach 2:
The single mask pattern serves multiple functions: it defines the deep concave portion for substrate contact, defines the shallow concave portion for electrode extraction, and provides alignment references for both structures. This multi-functional mask design reduces the total number of masks needed while ensuring precise formation of both concave portions
2Manufacturing precision
If prolonged heat treatment is used to form deep concave portion, then the deep concave portion can be formed effectively, but manufacturing cost increases
Solution Approach 1:
The patent replaces thermal processing (heat treatment) with a dry etching process to form the deep concave portion. This substitution eliminates the need for prolonged heat treatment while achieving the required depth and quality of the concave portion, thereby reducing manufacturing cost and process time
Solution Approach 2:
The patent changes the processing parameter from thermal energy (heat treatment temperature and time) to kinetic energy (etching gas flow rate, pressure, and power). By adjusting etching parameters such as CF4 gas flow rate and RF power, the method achieves precise control over concave portion depth and morphology without requiring prolonged heat treatment
Data Source
AI summary
There is formed a first concave portion that extends inside a semiconductor substrate from a main surface thereof. An insulating film is formed over the main surface, over a side wall and a bottom wall of the first concave portion so as to cover an element and to form a capped hollow in the first concave portion. A first hole portion is formed in the insulating film so as to reach the hollow in the first concave portion from an upper surface of the insulating film, and to reach the semiconductor substrate on the bottom wall of the first concave portion while leaving the insulating film over the side wall of the first concave portion. There is formed a second hole portion that reaches the conductive portion from the upper surface of the insulating film. The first and second hole portions are formed by the same etching treatment.