Tin Electroplating Liquid via Filling Additives
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Solution Overview
Problem
Existing methods for via filling in semiconductor integrated circuits and bump formation face challenges such as insufficient plating in indented areas, leading to void spaces and poor film quality, particularly with the use of tin or tin alloy plating liquids that contain α, β-unsaturated carboxylic acids or aromatic compounds, which result in burns and dendrites on the plated film surface.
Innovation Solution
Incorporating a specific α, β-unsaturated aldehyde compound within a defined concentration range in the tin or tin alloy electroplating liquid, along with a tin ion source and an acid, to enhance selective deposition and prevent voids, burns, and abnormal deposits, thereby achieving a high via fill effect and excellent film characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If tin or tin alloy plating liquid containing α, β-unsaturated carboxylic acid or aromatic compound is used, then plating can be performed on the material, but burns and dendrites are formed on the plated film surface resulting in poor film quality
Solution Approach 1:
The invention changes the chemical composition parameters of the plating liquid by replacing α, β-unsaturated carboxylic acids and aromatic compounds with specific additives (α, β-unsaturated aldehyde compound, aromatic aldehyde compound, or aromatic ketone compound) at controlled concentrations (0.01-5 g/L), thereby eliminating burns and dendrites while maintaining plating capability
Solution Approach 2:
The invention uses small amounts of specific organic compounds (0.01-5 g/L) as temporary additives that perform their function during plating and can be easily removed or decomposed, avoiding the formation of harmful deposits on the plated film surface
2Manufacturing precision
If plating is done on material with indented part, then via filling is achieved, but plated film is formed on outer surfaces and only thin plated film is formed in indented part leading to void spaces
Solution Approach 1:
The invention creates local quality differences in the plating process by using specific organic compounds that preferentially deposit in indented areas (via holes) while controlling deposition on outer surfaces, achieving uniform via filling without excessive outer surface plating
Solution Approach 2:
The invention employs periodic or controlled deposition action through specific additives that regulate the plating rate and distribution over time, allowing sufficient material to be deposited in via holes while preventing premature closure of via openings
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 solution enables a high via fill effect with deposits free of voids, providing a plated film with excellent soldering ability, color change resistance, and a good appearance, suitable for forming practical and effective tin or tin alloy bumps.
Implementation Method 1
tin or tin alloy electroplating liquid which is suitable for via filling which deposits tin or a tin alloy selectively in a via
Data Source
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AI summary
Tin or tin alloy plating liquid with a sufficient plated deposit can be formed in the opening without causing bums on the plated film surface or abnormal deposits, and which has a good via filling effect. When a specific α, β- unsaturated carbonyl compound is added into the tin or tin alloy plating liquid, the plating liquid with good via filling performance can be obtained, and the deposit which is substantially free of voids and burns or abnormal deposits on the deposit surface are reduced.