Semiconductor Hole Etching With Polymer-Controlled Taper Reduction
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Solution Overview
Problem
The increasing aspect ratio of memory holes and contact holes in three-dimensional semiconductor devices leads to a phenomenon where the diameter at the bottom is smaller than at the top, causing device faults and reducing yield and reliability.
Innovation Solution
A chemical etching method using a solution containing an acid and a polymer with a specific molecular weight range is employed to reduce the diameter difference between the top and bottom of high-aspect-ratio holes and slits, promoting uniform etching and reducing the tapered shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the aspect ratio of memory holes is increased to achieve higher integration density, then the storage capacity is improved, but the diameter difference between top and bottom increases causing device faults
Solution Approach 1:
The patent changes the chemical parameters of the etching solution by adding polymers with specific molecular weights (ranging from 1,000 to 1,000,000) to modify the etching rate profile. This parameter change enables the etching process to maintain uniform hole diameter throughout the high aspect ratio structure, resolving the contradiction between increased storage capacity and manufacturing precision.
Solution Approach 2:
The patent introduces polymer molecules as intermediary substances that mediate between the etchant and the hole walls. These polymers adsorb onto the hole surfaces and control the etching rate, preventing excessive etching at certain locations. This intermediary mechanism allows achieving uniform etching in high aspect ratio holes without compromising storage capacity.
2Ease of manufacture
If conventional etching methods are used for high aspect ratio holes, then the etching process is simple, but the tapered shape increases reducing yield and reliability
Solution Approach 1:
The patent creates a composite etching system by combining conventional etchants with polymer additives. This composite material approach maintains the simplicity of the etching process while significantly improving the etching uniformity and reducing tapered shapes. The composite etching solution achieves both ease of manufacture and high device yield by controlling the etching rate through polymer-etchant interactions.
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 improves the yield and reliability of semiconductor devices by minimizing the tapered shape of memory holes and slits, enhancing device performance.
Implementation Method 1
an etching method comprises etching a structure from inside of a hole or a slit provided in the structure, using a chemical etching solution containing an acid and a polymer
Implementation Method 2
using a chemical etching solution containing an acid and a polymer
Data Source
AI summary
An etching method according to the present embodiment includes etching a structure from inside of a hole or a slit provided in the structure, using a chemical etching solution containing an acid and a polymer.