Substrate Processing for High-Aspect-Ratio Etching Without Bowing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High aspect ratio patterns in semiconductor manufacturing face challenges such as shape abnormality, particularly 'bowing' of the inner peripheral surface of openings during etching, which existing methods struggle to prevent effectively while maintaining etching rate and pattern accuracy.
Innovation Solution
A substrate processing method involving alternating steps of etching and forming a protective silicon nitride film on the side walls of recesses, using silicon-containing and nitrogen-containing reactive species, with precise temperature control and thickness management to suppress shape abnormality and enhance aspect ratio formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a protective film is formed on the side wall of the recess to suppress lateral etching, then the shape abnormality is reduced, but the etching rate decreases and the aspect ratio formation becomes difficult
Solution Approach 1:
The patent changes the temperature parameter during film formation (heating to 200°C or higher) to alter the reactivity of reactive species. This temperature change enables selective formation of a thin protective film (20 nm or less) that suppresses lateral etching while maintaining vertical etching rate, thus resolving the contradiction between shape accuracy and etching productivity
Solution Approach 2:
The patent creates a protective film with locally optimized thickness (20 nm or less) specifically on the side wall of the recess. This localized thin film provides just enough protection against lateral etching without significantly impeding the vertical etching process, thereby maintaining both shape accuracy and etching rate
2Use of energy by moving object
If the temperature is increased to 200°C or higher during film formation, then the reactivity of reactive species increases and film formation is enhanced, but the etching process requires temperature reduction to 100°C or lower
Solution Approach 1:
The patent employs periodic alternation between film formation processes (at 200°C or higher) and etching processes (at 100°C or lower). This periodic temperature variation allows the system to optimize conditions for each specific operation, achieving high reactivity during film formation while maintaining appropriate conditions for etching
Solution Approach 2:
The patent dynamically adjusts the substrate temperature based on the current process step. The temperature is raised to 200°C or higher during film formation to enhance reactive species reactivity, then reduced to 100°C or lower during etching, making the temperature a dynamic parameter that adapts to process requirements
3Length of stationary object
If the aspect ratio is increased to 50 or more, then the vertical integration is improved, but the shape abnormality such as bowing increases
Solution Approach 1:
The patent applies preliminary action by forming a protective film on the side wall of the recess before performing the etching process. This pre-formed protective film prevents lateral etching and shape abnormality during the subsequent etching, enabling the formation of high aspect ratio structures (50 or more) while maintaining shape uniformity
Solution Approach 2:
The protective film acts as an intermediary layer between the etching environment and the recess side wall. This intermediary film selectively protects the side wall from lateral etching attacks, allowing the etching process to proceed vertically to achieve high aspect ratios while preventing shape abnormality such as bowing
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
The method effectively suppresses shape abnormality and increases the aspect ratio of semiconductor patterns while maintaining etching efficiency, ensuring accurate and precise pattern formation.
Implementation Method 1
silicon-containing reactive species are supplied into the first chamber, thereby adsorbing the silicon-containing reactive species onto the side wall of the recess
Implementation Method 2
nitrogen-containing reactive species are supplied into the first chamber to cause a reaction between the silicon-containing reactive species adsorbed onto the side wall of the recess and the nitrogen-containing reactive species, thereby forming the second film on the side wall of the recess
Implementation Method 3
the temperature of the substrate is adjusted to 200° C. or higher
Implementation Method 4
the temperature of the substrate is adjusted to 100° C. or lower
Data Source
AI summary
A substrate processing method includes: (a) carrying a substrate having a first film with a recess, and a mask into a first chamber; (b) adjusting the substrate temperature to 200° C. or higher; (c-1) supplying silicon-containing reactive species into the first chamber, thereby adsorbing the species onto the side wall of the recess; and (c-2) supplying nitrogen-containing reactive species into the first chamber, thereby forming a second film on the side wall of the recess; (d) carrying the substrate into a second chamber; and (e) adjusting the substrate temperature to 100° C. or lower; and (f) etching the bottom of the recess. Further, (a) to (f) are repeated in this order until an aspect ratio of a depth dimension from the opening of the mask to the bottom of the recess becomes 50 or more.