Photosensitive Paste Composition for Low-Ion Alkaline Development
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Solution Overview
Problem
Existing photosensitive pastes used in electronic component manufacturing face issues with thickening and insolubility in alkaline developers due to polyvalent metal ions, which affect the solubility and photolithographic properties of the materials.
Innovation Solution
A photosensitive paste formulation containing an inorganic powder with a polyvalent metal ion, an alkali-soluble polymer, and a photoinitiator, where the inorganic powder is coated with a ceramic layer to prevent adsorption and leaching of metal ions, maintaining low conductivity and solubility in alkaline developers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If glass powder containing alkaline earth metal elements and lanthanoids is kneaded with polymer having acidic functional groups to form paste, then the paste can be formed with inorganic and organic components, but polyvalent metal ions are adsorbed onto acidic functional groups and crosslinked with functional groups causing thickening (gelation) of the paste
Solution Approach 1:
A chelating agent is introduced as an intermediary substance that selectively binds to polyvalent metal ions, preventing their interaction with the acidic functional groups of the polymer. The chelating agent acts as a mediator that captures metal ions through coordinate covalent bonding, thereby eliminating the harmful crosslinking reaction between metal ions and polymer functional groups that causes paste thickening.
Solution Approach 2:
The invention converts the harmful effect of polyvalent metal ions (which cause thickening through unwanted crosslinking) into a beneficial effect by using the chelating agent to selectively complex these ions. The metal ions, instead of causing harm, are now controlled and stabilized by the chelating agent, allowing the paste to maintain its desired properties while still containing the inorganic glass powder with metal ions.
2Object-affected harmful factors
If low molecular weight organic acids and chelating agents are added to prevent adsorption of copper particles onto polymer, then surface coverage is achieved, but copper ions still leach into the paste causing insolubilization in alkaline developer and dark reaction with polymerizable monomers
Solution Approach 1:
The invention changes the molecular weight parameter of the chelating agent, transitioning from low molecular weight organic acids to high molecular weight chelating agents. This parameter change fundamentally alters the behavior of the system: high molecular weight chelating agents provide sustained chelation capability, prevent ion leaching, and maintain paste solubility in alkaline developers while preserving photolithographic properties.
Solution Approach 2:
The invention creates a composite system combining the polymer matrix, inorganic powder, photosensitive monomer, photoinitiator, and high molecular weight chelating agent. This composite formulation works synergistically: the chelating agent is integrated into the paste matrix to continuously manage metal ion behavior, preventing both particle adsorption and ion leaching, thereby achieving reliable photolithographic properties.
3Stability of the object's composition
If polyvalent metal ions leach into the paste, then salt formation with acidic functional groups occurs reducing polymer solubility in alkaline developer, but also dark reaction with polymerizable monomers occurs causing thickening
Solution Approach 1:
The high molecular weight chelating agent serves as an intermediary that intercepts polyvalent metal ions before they can interact with either the acidic functional groups or the polymerizable monomers. By binding metal ions through chelation, the agent prevents both the salt formation that reduces polymer solubility and the dark reaction that causes paste thickening, thereby maintaining paste stability and photolithographic functionality.
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 effectively prevents thickening and insolubility of the paste, ensuring stable solubility in alkaline developers and maintaining photolithographic properties, allowing for the formation of high-quality insulation and conductor layers in electronic components.
Implementation Method 1
polyvalent metal ions of alkaline earth metal elements or the like present on the surface of the glass powder and polyvalent metal ions of alkaline earth metal elements or the like leaching from the glass powder into the paste are adsorbed onto the acidic functional groups in the polymer
Implementation Method 2
a photosensitive monomer; and a photoinitiator
Data Source
AI summary
A photosensitive paste contains an inorganic powder containing an element that forms a polyvalent metal ion; an alkali-soluble polymer; a photosensitive monomer, and a photoinitiator. A dispersion of 1 wt % of the inorganic powder containing an element that forms a polyvalent metal ion in pure water has a conductivity of 170 mS/m or less at 10 minutes after dispersion.