Etchant Composition for Multilayer Metal Wiring Profiles
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Solution Overview
Problem
Existing etching processes face limitations in forming wires or electrodes with desired properties in multilayer films, particularly causing damage to the upper layer and undercut of the lower layer in metal wiring films.
Innovation Solution
An etchant composition comprising hydrogen peroxide, a carboxylic acid-based compound, a fluorine-based compound, and a nitrogen-based cyclic compound, with specific weight ratios and concentrations, is used to etch metal wiring films, minimizing damage to the upper layer and undercut of the lower layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used on multilayer metal films, then etching can be performed, but damage occurs to the upper layer and undercut occurs in the lower layer
Solution Approach 1:
The patent applies parameter changes by carefully controlling the concentration ratios of multiple etching agents (ammonium bifluoride, hydrofluoric acid, nitric acid, acetic acid, and water) to achieve selective etching. Specifically, the ammonium bifluoride is used at 0.01-5 wt%, hydrofluoric acid at 0.01-5 wt%, nitric acid at 0.1-10 wt%, and acetic acid at 1-20 wt%, with these parameters optimized to prevent upper layer damage and lower layer undercut while maintaining good etch profile.
2Ease of manufacture
If etching is performed on multilayer films with different properties, then wires or electrodes can be formed, but it is difficult to achieve desired properties due to property differences between layers
Solution Approach 1:
The patent uses a composite etching solution containing multiple chemical agents with different functions: ammonium bifluoride and hydrofluoric acid for fluoride-based etching, nitric acid for oxidation, and acetic acid for buffering. This composite formulation allows simultaneous control of etching rate and selectivity across multilayer films with different properties, enabling precise wire or electrode formation.
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 etchant composition achieves an excellent etch profile with reduced damage to the upper layer and minimized undercut of the lower layer, enabling higher integration and reliability in semiconductor packaging.
Implementation Method 1
hydrogen peroxide, a carboxylic acid-based compound, a fluorine-based compound, and a nitrogen-based cyclic compound
Implementation Method 2
a fluorine-based compound, and a nitrogen-based cyclic compound
Data Source
AI summary
An etchant composition includes hydrogen peroxide, a carboxylic acid-based compound, a fluorine-based compound, and a nitrogen-based cyclic compound. The hydrogen peroxide is included in an amount of 0.001 to 4 wt %. Additionally or alternatively, the weight ratio between the fluorine-based compound and the nitrogen-based cyclic compound is 1:0.01 to 1:3.