Metal Mask Etching for High Verticality Semiconductor Patterns
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Solution Overview
Problem
Wet etching methods for forming metal masks result in tapered etching patterns, leading to thin and unstable metal masks that are prone to trimming or peeling during semiconductor etching, making it difficult to achieve high verticality in etching shapes.
Innovation Solution
An etching method using a metal mask patterned with a reversal resist film pattern, where a metal paste is filled into the resist film pattern and baked to form a thick, vertically oriented metal mask, allowing for plasma etching without the limitations of wet etching, such as isotropic expansion and thinning of the mask.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet etching is used to form the etching pattern of the metal mask, then the etching process is simple and can be performed easily, but the opening expands in the width direction as well as in the depth direction, resulting in a tapered sidewall and reduced verticality of the etching pattern
Solution Approach 1:
The patent replaces the chemical wet etching process with a plasma etching process to form the metal mask pattern. Plasma etching provides anisotropic etching that maintains vertical sidewalls and prevents lateral expansion of the opening, thereby achieving high verticality while still allowing for effective pattern formation.
Solution Approach 2:
The patent changes the etching parameters by switching from wet chemical etching to plasma-based etching. This parameter change transforms the etching mechanism from isotropic (equal in all directions) to anisotropic (directional), enabling vertical sidewall formation and preventing the tapered shape that occurs with wet etching.
2Device complexity
If wet etching is used to form the etching pattern of the metal mask, then the process can be performed with simple equipment, but the metal mask becomes thinner in the depth direction and is easily trimmed or peeled off during semiconductor etching
Solution Approach 1:
The patent replaces wet chemical etching with plasma etching to form the metal mask. This substitution creates a more stable metal mask structure with vertical sidewalls and uniform thickness, preventing the thinning and tapering that leads to mask failure during semiconductor etching processes.
Solution Approach 2:
The patent achieves straight vertical sidewalls in the metal mask pattern by using plasma etching, which maintains a cylindrical or rectangular cross-section geometry rather than the conical or tapered shape produced by wet etching. This geometric control ensures uniform mask thickness and enhanced reliability.
3Ease of operation
If wet etching is used to form the etching pattern, then the chemical liquid can be applied directly to the metal film, but the opening widens isotropically in both longitudinal and transverse directions, making it difficult to achieve high verticality in the etching shape
Solution Approach 1:
The patent substitutes wet chemical etching with plasma etching to form the metal mask pattern. Plasma etching provides directional (anisotropic) etching that maintains vertical sidewalls and prevents lateral widening of the opening, thereby achieving high verticality in the etching shape while still being operationally straightforward.
Solution Approach 2:
The patent changes the fundamental etching parameter from isotropic chemical etching to anisotropic plasma etching. This parameter transformation enables vertical sidewall formation by controlling the etching direction, preventing the lateral expansion that occurs with wet etching and achieving the desired high verticality in the final etching shape.
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 enables the formation of metal masks with high verticality and stability, reducing the risk of mask failure during semiconductor etching and allowing for deeper, more precise etching without the need for separate resist film removal processes.
Implementation Method 1
a metal mask forming process of forming a metal mask having the etching pattern by removing the resist film while baking the metal paste by a heating control
Implementation Method 2
an etching process of a plasma etching of the semiconductor using the metal mask
Data Source
AI summary
A metal mask having an etching pattern having a very high verticality is formed, and an etching shape having a very high verticality is formed by etching a semiconductor with the metal mask as a mask.A resist film patterned with a reversal pattern obtained by reversing an etching pattern is formed on a semiconductor (resist film forming process, S100), a metal paste is filled in the reversal pattern of the resist film (metal paste filling process, S200), a metal mask having the etching pattern is formed by removing the resist film while baking the metal paste by a heating control (metal mask forming process, S300), and plasma etching is performed on the semiconductor by using the metal mask (etching process, S400).