Selective Plating Apparatus Inverted Nozzle Flow Control
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Solution Overview
Problem
Existing selective plating apparatuses result in uneven thickness of plated metal layers on semiconductor lead frames, particularly between the stage and tip end portions of leads, due to stagnation of electrolytic plating solution, which prevents the achievement of uniform thickness.
Innovation Solution
The selective plating apparatus features a mask member with supply and discharge openings at the bottom of a recessed portion and injection nozzles positioned upright near these openings, injecting electrolytic solution in an oblique direction to generate a swirling flow, reducing stagnation and enhancing the flow rate of the solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the electrolytic plating solution is supplied from above the mask plate as in conventional apparatuses, then the structure is simple, but the solution stagnates in the space causing uneven thickness of plated metal layers
Solution Approach 1:
The injection nozzle is inverted to inject the electrolytic plating solution from below the mask plate upward into the space, rather than from above as in conventional apparatuses. This inversion changes the flow direction to generate a swirling flow that prevents stagnation and ensures uniform solution distribution, thereby achieving uniform plated metal layer thickness while maintaining structural simplicity
Solution Approach 2:
The invention utilizes hydraulic principles by optimizing the flow dynamics of the electrolytic plating solution through the injection nozzle positioned below the mask plate. The solution is injected upward to create a swirling flow pattern that enhances fluid circulation and prevents stagnation, ensuring uniform distribution across the exposed surfaces for consistent plating thickness
2Manufacturing precision
If the injection nozzle is positioned upright as in conventional apparatuses, then the structure is simple, but it causes stagnation of electrolytic solution and uneven plating thickness
Solution Approach 1:
The injection nozzle is inverted and positioned below the mask plate, injecting solution upward into the space. This inversion fundamentally changes the flow dynamics from a stagnant vertical flow to a dynamic swirling flow that circulates throughout the space, preventing stagnation and ensuring uniform solution distribution for consistent plating thickness
Solution Approach 2:
The invention transforms the static, stagnant solution flow into a dynamic swirling flow by injecting the electrolytic plating solution from below the mask plate upward. This dynamic flow pattern continuously circulates the solution throughout the space, preventing stagnation and ensuring uniform distribution, thereby achieving uniform plated metal layer thickness
3Manufacturing precision
If conventional mask member structure is used with simple openings, then the device is simple, but it cannot prevent solution stagnation and achieve uniform plating
Solution Approach 1:
The mask plate is segmented with multiple supply openings and discharge openings positioned at the bottom, rather than a single opening structure. This segmentation allows the electrolytic plating solution to be distributed through multiple pathways, preventing stagnation and ensuring uniform flow distribution across the entire exposed surface, thereby achieving uniform plated metal layer thickness
Solution Approach 2:
The mask member structure incorporates hydraulic principles by positioning supply and discharge openings at the bottom to facilitate upward solution flow. This configuration, combined with the inverted injection nozzle, creates a controlled hydraulic flow pattern that prevents stagnation and ensures uniform solution distribution for consistent plating
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
This configuration significantly reduces unevenness in the thickness of plated metal layers, ensuring a uniform thickness on both the stage and tip end portions of the lead frames.
Implementation Method 1
injecting electrolytic solution in an oblique direction to generate a swirling flow, reducing stagnation and enhancing the flow rate of the solution
Implementation Method 2
selective electrolytic plating to a metal member onto which a mask member is attached so as to expose predetermined parts of a surface of the metal member, and so as to cover the predetermined parts of the surface with a plated metal layer
Data Source
AI summary
A selective plating apparatus for applying selective electrolytic plating to a metal member includes: a mask member having a recess portion so that a space is formed to which predetermined parts of a surface of the metal member are exposed when the mask member is attached to the metal member, and having at least one supply opening for supplying electrolytic plating solution into the space and a discharge opening for discharging the electrolytic plating solution from the space both formed in a bottom portion of the recess portion; and at least one injection nozzle which injects the electrolytic plating solution in an oblique direction with respect to the predetermined parts of the surface of the metal member, and is arranged in vicinity of the supply opening.