Plasma Etch Substrate Planarization via Thermal Zone Control
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Solution Overview
Problem
In semiconductor fabrication, precise planarization of the upper surface of a semiconductor substrate is challenging due to variations in surface topography, which complicates the addition of additional layers and requires advanced temperature control during plasma etching.
Innovation Solution
A method utilizing a substrate support assembly with independently controlled thermal elements to create a spatial and temporal temperature profile, allowing for precise control of the etch rate across the substrate surface, enabling planarization by plasma etching while maintaining the substrate in a plasma etch chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma etching is used without temperature control, then the etching process is simple and fast, but the surface topography variations increase and planarization precision deteriorates
Solution Approach 1:
The substrate support assembly is divided into multiple independently controllable thermal zones, each with its own heating element. This segmentation allows different regions of the substrate to be heated to different temperatures, enabling precise control of etch rates across the substrate surface to achieve planarization while maintaining manageable system complexity through modular control
Solution Approach 2:
Different regions of the substrate are exposed to different temperatures through the independently controlled thermal zones. This local quality approach allows specific areas with higher topography variations to receive higher temperatures for increased etch rates, while other regions maintain lower temperatures, thereby achieving precise planarization control without requiring uniform temperature control across the entire substrate
2Manufacturing precision
If uniform temperature is applied across the substrate, then the temperature control is simple, but the etch rate uniformity deteriorates due to surface topography variations
Solution Approach 1:
The heating system is segmented into multiple independent thermal zones with individual control, allowing each zone to be optimized for its specific region of the substrate. This segmentation enables precise adjustment of etch rates in different areas to compensate for topography variations, achieving uniform etching results while using a modular thermal control architecture
Solution Approach 2:
The temperature parameter is varied across different spatial zones of the substrate through the array of independently controlled thermal elements. By changing the temperature parameter locally in different regions, the etch rate is adjusted to compensate for surface topography variations, achieving uniform etching without requiring complex non-temperature control mechanisms
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 method effectively reduces surface topography variations by controlling the etch rate based on localized temperatures, achieving a planarized substrate surface within a predetermined time using process gases like HBr, C4F8, NF3, and CH2F2, thereby simplifying the fabrication process.
Implementation Method 1
The thermal control elements of the array of independently controlled thermal control elements are operable to control the spatial and temporal temperature of the support surface of the substrate support assembly to form independently controllable heater zones
Implementation Method 2
Process gas is supplied into the chamber and the process gas is energized into a plasma state
Implementation Method 3
The upper surface of the semiconductor substrate is planarized by plasma etching the upper surface of the semiconductor substrate while powering the array of independently controlled thermal control elements to achieve the desired temperature profile across the upper surface of the semiconductor substrate thereby removing the calculated amount of Si-containing material
Data Source
AI summary
A method of planarizing an upper surface of a semiconductor substrate in a plasma etch chamber comprises supporting the substrate on a support surface of a substrate support assembly that includes an array of independently controlled thermal control elements therein which are operable to control the spatial and temporal temperature of the support surface of the substrate support assembly to form independently controllable heater zones which are formed to correspond to a desired temperature profile across the upper surface of the semiconductor substrate. The etch rate across the upper surface of the semiconductor substrate during plasma etching depends on a localized temperature thereof wherein the desired temperature profile is determined such that the upper surface of the semiconductor substrate is planarized within a predetermined time. The substrate is plasma etched for the predetermined time thereby planarizing the upper surface of the substrate.