Polyaminoamide Leveling Agent for Copper Electroplating
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Solution Overview
Problem
Current copper electroplating processes face challenges in achieving uniform metal deposits on nanometer and micrometer scales without forming defects like voids and seams, particularly in features with high aspect ratios, such as through silicon vias and copper pillars, which require advanced leveling agents to ensure planar surfaces and reduced overplating.
Innovation Solution
A composition comprising a source of metal ions, an accelerating agent, and a polyaminoamide additive without aromatic moieties, which provides improved leveling properties by reducing overplating and void formation, especially in features with nanometer and micrometer dimensions, is used in copper electroplating baths to deposit metal layers with reduced mounding and increased planarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional leveling agents with aromatic moieties are used, then metal layers can be deposited, but overplating and mounding occur leading to non-planar surfaces
Solution Approach 1:
The invention changes the chemical structure of the leveling agent by removing aromatic moieties from the polyaminoamide backbone. This structural parameter change eliminates the harmful overplating and mounding effects while maintaining the desired surface planarity in electroplated metal layers.
Solution Approach 2:
The polyaminoamide leveling agent provides localized control of metal deposition by selectively adsorbing at specific sites on the substrate surface. This local action prevents excessive metal accumulation (mounding) in certain areas while ensuring uniform coverage across the entire surface.
2Manufacturing precision
If copper electroplating is performed in features with high aspect ratios, then metal lines are formed, but voids and seams defect form within the deposits
Solution Approach 1:
The leveling agent is introduced into the electroplating bath before the plating process begins. It pre-adsorbs on the substrate surface and within feature walls, creating a controlled deposition environment that prevents void and seam formation during the subsequent metal deposition in high aspect ratio features.
Solution Approach 2:
The polyaminoamide leveling agent acts as an intermediary substance between the metal ions in solution and the substrate surface. It mediates the deposition process by controlling nucleation and growth patterns, ensuring continuous, void-free metal filling in high aspect ratio structures.
3Productivity
If metal layers with overplating are deposited, then features are filled, but additional material removal is required increasing process time
Solution Approach 1:
The invention converts the potential harm of uncontrolled deposition into a benefit by using the leveling agent to promote uniform metal growth. This eliminates the need for extensive post-plating removal processes, thereby reducing manufacturing time and increasing overall 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 use of polyaminoamide additives in copper electroplating baths results in metal layers with significantly reduced overplating and voids, enabling more efficient chemical mechanical polishing, less material removal, and reduced defect risk across a wide range of aperture sizes, from nanometers to micrometers, enhancing the manufacturing of electronic devices and circuits.
Implementation Method 1
leveling agents are used to provide a substantially planar surface over the filled features
Implementation Method 2
composition for metal electroplating for void free bottom-up filling of features
Data Source
Figure 1a~1c
Figure 2a~3a
Figure 3b~4a
AI summary
A composition comprising a source of metal ions and at least one additive comprising at least one polyaminoamide, said polyaminoamide comprising the structural unit represented by formula I or derivatives of the polyaminoamide of formula I obtainable by complete or partial protonation, N-functionalization or N-quaternization with a non-aromatic reactant, wherein D6 is, for each repeating unit 1 to s independently, a divalent group selected from a saturated or unsaturated C1-C20 organic radical, D7 is, for each repeating unit 1 to s independently, a divalent group selected from straight chain or branched C2-C20 alkanediyl, which may optionally be interrupted by heteroatoms or divalent groups selected from O, S and NR10, R1 is, for each repeating unit 1 to s independently, selected from H, C1-C20 alkyl, and C1-C20 alkenyl, which may optionally be substituted by hydroxyl, alkoxy or alkoxycarbonyl, or, together with R2, may form a divalent group D8, and R2 is, for each repeating unit 1 to s independently, selected from H, C1-C20 alkyl, and C1-C20 alkenyl, which may optionally be substituted by hydroxyl, alkoxy or alkoxycarbonyl, or, together with R1, may form a divalent group D8, and D8 is selected from straight chain or branched C1-C18 alkanediyl, which may optionally be interrupted by heteroatoms or divalent groups selected from O, S and NR10, s is an integer from 1 to 250, R10 is selected from H, C1-C20 alkyl, and C1-C20 alkenyl, which may optionally be substituted by hydroxyl, alkoxy or alkoxycarbonyl.