Aqueous Acid Bath for Copper Electrolytic Deposition
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Solution Overview
Problem
Existing bath solutions are inadequate for achieving uniform and reproducible copper deposition in micro structures such as through holes, trenches, and blind micro vias on printed circuit boards and semiconductor wafers, often resulting in uneven surfaces and voids, which complicates the production of complex conductor structures.
Innovation Solution
An aqueous acid bath containing copper ions, acid ions, brightener compounds, and leveler compounds, specifically synthetically produced non-functionalized peptides and functionalized amino acids, is used for electrolytic deposition, ensuring uniform copper distribution and preventing ski-slope or dimple formations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional organic additives (brighteners and carriers) are added to acid electrolytic copper baths, then bright deposits can be obtained, but uniform deposition in micro structures (trenches, BMVs, through vias) cannot be achieved
Solution Approach 1:
The patent changes the chemical nature of the additive from conventional organic brighteners/carriers to amino acids and their derivatives. This parameter change in the additive chemistry enables both bright deposits and uniform deposition in micro structures by providing a different mechanism of action that addresses the diffusion limitations in small structures while maintaining surface brightness.
Solution Approach 2:
The patent uses composite additive systems containing amino acids combined with other bath components (such as gelatine compounds, sulfur-containing compounds, and polyether compounds) to achieve multiple functions simultaneously: brightness, uniformity in micro structures, and controlled deposition morphology. This composite approach allows the bath to address multiple contradictory requirements.
2Reliability
If diffusion of metal ions and additives is dominant in very small structures, then deposition control becomes difficult, but this leads to insufficient or excessive deposition and formation of defects
Solution Approach 1:
The patent changes the physical-chemical parameters of the additives by using amino acids with specific molecular weights and structures. These parameter changes affect the diffusion behavior and adsorption characteristics of the additives, enabling better control over deposition in small structures where diffusion is dominant, thereby achieving uniform thickness without defects.
Solution Approach 2:
Amino acids act as intermediary substances that mediate between the metal ions and the substrate surface. They facilitate controlled deposition by interacting with both the copper ions and the surface, providing a buffering effect that ensures uniform deposition even in structures where diffusion processes are dominant and difficult to control.
3Productivity
If conventional additives are used, then copper deposition can proceed, but hollow spaces (voids) form in the copper deposit or structures are reproduced on the surface
Solution Approach 1:
The patent employs composite additive systems including amino acids, gelatine compounds, and other auxiliary additives that work synergistically to ensure complete filling of micro structures without voids while maintaining smooth surfaces. This composite formulation addresses the缺陷 of conventional single-additive systems that either fill structures but create surface defects or maintain surface quality but leave voids.
Solution Approach 2:
The patent changes the molecular characteristics and concentration parameters of the additives to optimize deposition behavior. By adjusting parameters such as amino acid concentration, molecular weight distribution, and combination with other compounds, the system achieves complete structure filling with smooth surfaces, eliminating voids and surface reproductions while maintaining productivity.
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 uniform copper deposition in micro structures with minimal voids and deformations, ensuring smooth, even surfaces and ideal rectangular cross-sections, thereby improving the reliability and reproducibility of conductor structures.
Implementation Method 1
aqueous, acid bath for the electrolytic deposition of copper
Implementation Method 2
electrolytic deposition of copper
Data Source
AI summary
An aqueous, acid bath for the electrolytic deposition of copper contains at least one copper ion source, at least one acid ion source, at least one brightener compound, and at least one leveler compound, and generates a very uniform copper deposit in particular in blind micro vias (BMVs) and trenches. The leveler compound is selected from among synthetically produced non-functionalized peptides, synthetically produced functionalized peptides, and synthetically produced functionalized amino acids.