Plasma Etching of HAR Openings With Focus Ring Temperature Zoning
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Solution Overview
Problem
Conventional dry etching methods struggle to achieve the desired depth and alignment of high aspect ratio openings in the outer regions of microelectronic device structures, leading to misalignment and twisting of features, which hampers the development of high-capacity memory devices.
Innovation Solution
A processing system with a plasma chamber, electrostatic chuck, and cooling system is used to maintain temperature differences between the microelectronic device structure and focus ring, combined with selective exposure to etch gas precursors with varying diffusivity coefficients to form high aspect ratio openings uniformly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dry etching methods are used to etch high aspect ratio openings, then the etching process can be performed, but the desired depth and alignment cannot be achieved in the outer region, resulting in misalignment and twisting of features
Solution Approach 1:
The patent applies local quality by introducing a focus ring that creates a temperature gradient across the substrate, with the outer region maintained at a lower temperature than the center region. This localized temperature control optimizes the etching process specifically for the outer region, improving etch depth and alignment without compromising the overall process. The focus ring structure enables different thermal conditions in different spatial zones to address the specific etching challenges in the outer region.
Solution Approach 2:
The patent utilizes parameter changes by controlling the temperature of the focus ring and substrate to optimize etching performance. By adjusting the temperature parameters of the focus ring (maintaining it at a lower temperature than the substrate center), the patent achieves improved etch rates and reduced twisting in the outer region. This parameter control enables the etching process to achieve desired depth and alignment that cannot be obtained with conventional uniform temperature conditions.
2Productivity
If the depth of HAR openings is increased to improve storage capacity, then storage capacity increases, but twisting and misalignment of HAR openings worsens, especially in the outer region
Solution Approach 1:
The focus ring creates localized thermal zones that improve etching uniformity across different regions of the substrate. By maintaining the outer region at a lower temperature, the patent reduces twisting and improves alignment of HAR openings, enabling deeper etching with better precision. This localized quality control allows the patent to achieve both increased depth and maintained alignment quality.
Solution Approach 2:
The patent employs dynamic temperature control through the focus ring system, which can be adjusted during the etching process. The temperature gradient is dynamically maintained to optimize etching at different depths, preventing twisting as the etch front progresses. This dynamic control enables the system to maintain precision throughout the deep etching process required for high storage capacity.
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 enhances etch rates and alignment of features, reducing twisting and bowing, thereby improving the uniformity and accuracy of high aspect ratio openings in microelectronic device structures.
Implementation Method 1
A coolant is introduced into the processing system to remove heat from the microelectronic device structure and from the focus ring
Implementation Method 2
One or more etch gas precursors is introduced into the processing system and the one or more etch gas precursors are excited to generate one or more etch plasmas
Implementation Method 3
The radical species travel from a showerhead in a processing system and upon contact with the microelectronic device structure, remove one or more materials in the microelectronic device structure
Implementation Method 4
an electrostatic chuck positioned on a pedestal and configured to hold a microelectronic device structure
Data Source
AI summary
A method of processing a microelectronic device structure comprises disposing a microelectronic device structure comprising one or more materials in a processing system. A coolant is introduced proximal to the microelectronic device structure and to a focus ring adjacent to the microelectronic device structure. One or more etch gas precursors are introduced into the processing system and the etch gas precursors are excited to generate one or more etch plasmas. One or more of the etch plasmas exhibit a different diffusivity coefficient than other of the etch plasmas. An inner region of the microelectronic device structure is exposed to at least one etch plasma and an outer region is exposed to at least one other etch plasma. The at least one etch plasma exhibits a diffusivity coefficient less than or equal to a diffusivity coefficient of the at least one other etch plasma. At least a portion of one or more materials of the microelectronic device structure is removed to form high aspect ratio openings and high aspect ratio features are formed in the high aspect ratio openings.