Semiconductor Depression Filling via Selective Epitaxial Growth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the process of filling depressions on semiconductor wafers with semiconductor material, existing methods face challenges in minimizing the etching damage to the epitaxial regions formed, as the etching rate of impurity-containing epitaxial regions is higher than that of regions without impurities, potentially causing damage during the removal of excess semiconductor material.
Innovation Solution
A method involving the sequential formation of thin films with and without impurities, followed by epitaxial growth and gas phase doping, where the etching is controlled to selectively remove the impurity-free films while maintaining the integrity of the epitaxial regions, using a processing apparatus with precise gas supply and heating controls to manage the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas phase doping is performed to add impurity to the epitaxial region, then the electrical properties of the semiconductor device are improved, but the etching rate of the epitaxial region increases causing damage during subsequent etching steps
Solution Approach 1:
The patent forms a capping film made of material different from the semiconductor substrate before performing etching. This capping film is deposited in advance to protect the epitaxial region that has been doped with impurity. During the etching step, the capping film serves as a protective layer that prevents etching damage to the impurity-containing epitaxial region, while allowing selective removal of excess semiconductor material from the depression walls.
2Manufacturing precision
If excess semiconductor material on the wall surface is removed by etching, then the precision of the depression filling is improved, but the epitaxial region suffers from etching damage
Solution Approach 1:
The patent introduces a capping film as an intermediary protective layer between the etching process and the epitaxial region. This capping film, made of material different from the semiconductor substrate, acts as a mediator that allows the etching process to selectively remove excess semiconductor material while protecting the underlying epitaxial region from etching damage. The capping film can be selectively removed after serving its protective function.
3Productivity
If the depression is completely filled with semiconductor material, then the productivity is improved, but the excess material on the wall surface cannot be removed without damaging the epitaxial region
Solution Approach 1:
The patent performs the action of depositing a protective capping film in advance, before the etching step. This preliminary action enables subsequent easy removal of excess semiconductor material from the depression walls without worrying about damaging the epitaxial region. The capping film is formed while the epitaxial region is still present, providing immediate protection for the subsequent material removal process.
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 effectively reduces the etching influence on the epitaxial regions filled into depressions, ensuring the semiconductor material is filled efficiently while minimizing damage, thus maintaining the quality of the epitaxial growth.
Implementation Method 1
forming an epitaxial region conforming to crystals of the semiconductor substrate from the semiconductor material of the first thin film moved toward a bottom of the depression
Implementation Method 2
by annealing the workpiece within a vessel
Implementation Method 3
performing gas phase doping upon the epitaxial region
Data Source
AI summary
A method of filling a depression of a workpiece is provided. The method includes forming a first thin film made of a semiconductor material substantially not containing an impurity along a wall surface which defines the depression, forming an epitaxial region conforming to crystals of the semiconductor substrate from the semiconductor material of the first thin film moved toward a bottom of the depression by annealing, etching the first thin film remaining on the wall surface, performing gas phase doping upon the epitaxial region, forming a second thin film made of a semiconductor material substantially not containing an impurity along the wall surface, further forming an epitaxial region from the semiconductor material of the second thin film moved toward the bottom of the depression by annealing, and performing gas phase doping upon the second thin film remaining on the wall surface and the epitaxial region.