Redistribution Structure Etching for Selective Seed Layer Removal
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Solution Overview
Problem
The semiconductor industry faces challenges in forming conductive features with minimal loss and damage during the etching process, particularly in achieving high etching selectivity between seed layers and conductive materials, which affects the precision and reliability of device packaging.
Innovation Solution
The use of an etching solution containing a protective agent with multiple active sites, such as a polyamine, that selectively adsorbs on the conductive material to reduce the etching rate of the conductive material while increasing the etching rate of the seed layer, thereby minimizing the loss and damage of the conductive material and improving etching selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching solutions are used to remove seed layers, then the seed layer can be etched, but the conductive material suffers from excessive loss and damage due to low etching selectivity
Solution Approach 1:
A protective agent is introduced as an intermediary substance that selectively adsorbs onto the conductive material surface during etching. This protective agent acts as a mediator that differentially protects the conductive material while allowing the seed layer to be etched away, thereby achieving high etching selectivity and minimizing conductive material loss
Solution Approach 2:
The etching solution parameters are modified by adding a protective agent that changes the chemical environment during etching. This parameter change enables selective adsorption onto the conductive material, altering the etching rate differential between the seed layer and conductive material to achieve superior selectivity
2Manufacturing precision
If etching is performed to remove the seed layer, then the seed layer is removed, but the conductive material surface becomes rough and damaged
Solution Approach 1:
The protective agent serves as a protective intermediary that adsorbs onto the conductive material surface during etching, forming a protective layer that prevents direct contact between the etchant and the conductive material, thereby maintaining surface quality and preventing roughness and damage
Solution Approach 2:
The protective agent provides beforehand cushioning by pre-adsorbing onto the conductive material surface before the etching process fully commences, creating a protective barrier that cushions the conductive material against the harmful effects of the etchant and prevents surface degradation
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 reduces the loss and damage of the conductive material, enhances etching selectivity, and improves the surface roughness and reliability of the conductive features, facilitating more precise and reliable device packaging.
Implementation Method 1
an etching solution containing a protective agent with multiple active sites, such as a polyamine, that selectively adsorbs on the conductive material to reduce the etching rate of the conductive material
Data Source
AI summary
A method of forming a redistribution structure includes providing a dielectric layer. The dielectric layer is patterned to form a plurality of via openings. A seed layer is formed on the dielectric layer and filling in the plurality of via openings. A patterned conductive layer is formed a on the seed layer, wherein a portion of the seed layer is exposed by the patterned conductive layer. The portion of the seed layer is removed by using an etching solution, thereby forming a plurality of conductive lines and a plurality of vias. During the removing the portion of the seed layer, an etch rate of the patterned conductive layer is less than an etch rate of the seed layer.