Cyclic Recess Filling for Void-Free High-Aspect-Ratio Isolation
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Solution Overview
Problem
Existing methods for filling recesses in substrates during electronic device manufacturing often result in void formation, which compromises device isolation and structural integrity, and may require size constraints that limit device packing density.
Innovation Solution
A method and apparatus for filling recesses using a cyclic deposition process, where a first reactant forms active species to modify the top portion of the recess, a second reactant reacts with the bottom portion to form chemisorbed material, and a third reactant forms active species to deposit material, allowing for seamless filling of high aspect ratio recesses without voids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional filling methods are used, then the recess can be filled with material, but void formation occurs that compromises device isolation and structural integrity
Solution Approach 1:
The filling process is segmented into multiple sequential steps: (1) depositing a first material layer that conforms to the recess profile, (2) planarizing the surface to remove peaks and fill valleys, and (3) depositing a second material layer to complete the fill. This segmentation prevents void formation by ensuring each layer is properly formed and planarized before the next is added, thereby maintaining both manufacturing precision and reliability.
Solution Approach 2:
The first material layer is deposited in advance to conformally coat the recess walls and bottom before the final filling step. This preliminary action ensures that the recess structure is properly prepared and stabilized, preventing void formation during subsequent processing and ensuring reliable device isolation and structural integrity.
2Manufacturing precision
If recess depth is decreased to prevent void formation, then voids are reduced, but device isolation effectiveness is reduced
Solution Approach 1:
The filling process is divided into multiple steps with intermediate planarization. The first material layer is deposited to conformally fill the recess, then the surface is planarized to create a flat topography. This segmentation allows deep recesses to be filled completely without voids while maintaining the necessary recess depth for effective device isolation.
Solution Approach 2:
The multi-step filling process with planarization maintains continuous useful action by ensuring that material is continuously deposited and reshaped to fill the entire recess volume. This continuous process ensures complete filling of deep recesses while maintaining the recess depth required for effective device isolation, preventing both voids and isolation failures.
3Manufacturing precision
If recess top opening is enlarged to prevent void formation, then voids are reduced, but IC real estate is consumed
Solution Approach 1:
The first material layer is deposited in advance to conformally fill the recess with the original top opening dimensions. This preliminary filling action prevents void formation by ensuring complete material coverage before any planarization occurs, eliminating the need to enlarge the top opening and preserving IC real estate.
Solution Approach 2:
The continuous multi-step filling process with planarization ensures that the recess is completely filled using the original top opening dimensions. Material is continuously deposited and reshaped to fill the entire volume, preventing voids without requiring additional IC real estate through top opening enlargement.
4Manufacturing precision
If high temperature processing is used to improve material quality, then material quality improves, but oxidation of underlying and surrounding material occurs
Solution Approach 1:
The deposition temperature parameter is changed from conventional high temperatures to low temperatures (below 450°C, preferably below 350°C). This parameter change maintains high material quality through the multi-step deposition and planarization process while preventing oxidation of the substrate and surrounding materials, eliminating the trade-off between material quality and oxidation prevention.
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 enables seamless filling of high aspect ratio recesses with high-quality dielectric material, preventing seam and void formation, and eliminating the need for post-treatment annealing, thus improving device isolation and structural integrity while maintaining high device packing density.
Implementation Method 1
introducing a first reactant, to form first active species, for a first pulse time to the substrate at a first pressure, wherein the first active species modify a first portion (e.g., top) of a surface of the recess
Implementation Method 2
introducing a second reactant for a second pulse time to the substrate, wherein the second reactant reacts with a second portion (e.g., bottom) of the surface of the recess to form chemisorbed material on the second portion
Implementation Method 3
introducing a third reactant, to form second active species, for a third pulse time to the substrate at a second pressure, wherein the second active species react with the chemisorbed material to form deposited material
Implementation Method 4
In accordance with further examples, an anisotropic plasma can be formed during the step of introducing a first reactant. And, in accordance with yet further examples, an isotropic plasma can be formed during the step of introducing a third reactant
Data Source
AI summary
There is provided a method of filling one or more recesses by providing the substrate in a reaction chamber; introducing a first reactant, to form first active species, for a first pulse time to the substrate; introducing a second reactant for a second pulse time to the substrate; and introducing a third reactant, to form second active species, for a third pulse time to the substrate. An apparatus for filling a recess is also disclosed and a structure formed using the method and/or apparatus is disclosed.