Inkjet Resist Fine Pattern Printing with Vertical Edge Control
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Solution Overview
Problem
Existing inkjet printing methods for forming etching or plating resist patterns in PCB manufacturing face challenges such as high costs, low productivity, and difficulty in achieving a vertical edge due to ink spreading, leading to inadequate etching and plating results.
Innovation Solution
A method and apparatus using inkjet printing to simultaneously discharge photocurable resist ink and partition-forming ink on a substrate, applying optical energy to form a vertical boundary and prevent spreading, resulting in a semi-cured, gelatinous resist pattern with sufficient thickness for effective etching and plating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If inkjet printing method is used to form resist pattern, then manufacturing flexibility and cost are improved, but edge verticality and pattern thickness are worsened due to ink spreading
Solution Approach 1:
The patent applies preliminary action by discharging partition-forming ink ahead of the resist ink to create a boundary structure before the resist ink is deposited. This pre-formed partition prevents the resist ink from spreading laterally, ensuring vertical edges are maintained from the moment of deposition without requiring post-processing or substrate treatment modifications
Solution Approach 2:
The partition-forming ink acts as an intermediary element between the resist ink and the substrate. It creates a physical and chemical barrier that mediates the interaction between the resist ink and substrate surface, preventing direct contact that would cause spreading while still allowing the resist ink to be deposited in the desired pattern area
2Manufacturing precision
If hydrophobic treatment or stepped portion is formed on substrate, then contact angle is increased and ink spreading is reduced, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent extracts the edge control function from the substrate and transfers it to the partition-forming ink. Instead of modifying the substrate to control ink behavior, the substrate remains unchanged and the partition-forming ink carries the boundary-defining function, eliminating the need for hydrophobic treatments or stepped structures on the substrate
Solution Approach 2:
The patent changes the approach from modifying substrate parameters (surface energy, geometry) to controlling ink discharge parameters (timing, position, amount). By precisely controlling when and where the partition-forming ink is discharged relative to the resist ink, the system achieves edge control through process parameters rather than material or substrate modifications
3Area of stationary object
If ink is allowed to spread on substrate, then coverage area is improved, but edge rounding occurs and etching/plating effectiveness is reduced
Solution Approach 1:
The partition-forming ink is discharged in advance to establish boundary markers before the resist ink is deposited. These pre-formed partitions create confined spaces that guide the resist ink deposition and prevent lateral spreading, ensuring that the resist ink remains within the desired pattern boundaries with vertical edges for effective etching and plating protection
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 method achieves a vertical edge in the resist pattern, enhancing etching and plating results, and allows for uniform line straightness, particularly beneficial for high-frequency circuits like 5G millimeter wave communication.
Implementation Method 1
applying optical energy to the discharged photocurable resist ink
Implementation Method 2
simultaneously discharging a photocurable resist ink and a partition-forming ink
Data Source
AI summary
A method for forming a resist fine pattern uses inkjet printing for printing an ink along a path to form a resist fine pattern on a substrate having the same surface energy. The method includes an ejecting step of simultaneously discharging a photocurable resist ink and a partition-forming ink that are spaced from each other on the front side and the rear side of the path and applying the light energy to the discharged photocurable resist ink. The intensity of light is set so that, as the photocurable resist ink is semi-cured and is ejected on the substrate in a gelatinous state, the ink forms a boundary that is vertical with respect to the partition-forming ink ejected on the substrate and the spreading of the photocurable resist ink is prevented, and the photocurable resist ink is cured after both the photocurable resist ink and the partition-forming ink are completely ejected.