Semiconductor Etching Sequence Using HCl and Cl2 for Speed and Selectivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor device fabrication processes face challenges with slow etching at low temperatures, leading to reduced throughput and limited selectivity, which can hinder device performance and increase processing times.
Innovation Solution
A method involving initial etching with hydrogen chloride and fast etching with chlorine gas, utilizing varying pressures, temperatures, and flow rates to enhance processing speed and selectivity, including cyclic deposition and etch operations to form doped semiconductor layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low temperature processing is used, then device performance is improved, but etching speed decreases and throughput is reduced
Solution Approach 1:
The etching process is divided into two distinct stages: initial etching using HCl at low temperature for selectivity, and fast etching using Cl2 at higher temperature for speed. This segmentation allows each stage to optimize for its specific function, resolving the contradiction between device performance and throughput.
Solution Approach 2:
The process dynamically transitions between different etching conditions - starting with low-temperature HCl etching and then switching to high-temperature Cl2 etching. This dynamic adjustment of processing parameters enables the system to achieve both selectivity and speed throughout the etching sequence.
2Reliability
If low temperature processing is used, then device performance is improved, but etching selectivity is limited
Solution Approach 1:
The etching process is segmented into two stages with different chemistries: HCl for initial etching providing high selectivity, and Cl2 for fast etching. This segmentation ensures that selectivity requirements are met in the initial stage while maintaining overall process control.
Solution Approach 2:
The process changes chemical parameters by switching from HCl to Cl2 gas, and changes temperature parameters from low to high. These parameter changes enable the system to achieve both high selectivity and fast etching rates at different stages.
3Manufacturing precision
If cyclic processing is used, then layer formation is achieved, but processing time increases to 1 hour or higher
Solution Approach 1:
The cyclic processing is made dynamic by varying the etching conditions between cycles - using fast Cl2 etching for most cycles and switching to selective HCl etching only when needed. This dynamic approach maintains layer formation quality while dramatically reducing total processing time.
Solution Approach 2:
The process uses parameter changes by alternating between different gas compositions (HCl vs Cl2) and temperature settings during cyclic processing. This allows the system to achieve both precise layer formation and reduced processing time by optimizing parameters for each cycle's specific requirements.
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 fast and selective etching of semiconductor layers, reducing processing time and improving device performance by forming doped semiconductor epitaxial layers efficiently.
Implementation Method 1
etching a layer of a substrate using a first pressure and a first composition including hydrogen chloride
Implementation Method 2
etching the layer using a second pressure and a second composition including chlorine (Cl2) gas
Implementation Method 3
depositing a layer on a substrate using a first temperature and a first pressure
Data Source
AI summary
Embodiments described herein generally relate to semiconductor device fabrication, and more particularly, to systems and methods that include initial etching and fast etching. In one or more embodiments, a method of substrate processing includes etching a layer of a substrate using a first pressure and a first composition including hydrogen chloride. The etching includes flowing the first composition for a first time period and at a first flow rate. The method includes etching the layer using a second pressure and a second composition including chlorine (Cl2) gas, and the etching includes flowing the second composition for a second time period less than the first time period and at a second flow rate less than the first flow rate. The second time period is a time ratio of the first time period, and the time ratio is 1:15 or less.