Movable Shielding Plate for Uniform Electrolytic Plating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for forming bumps and wiring on semiconductor wafers using electrolytic plating result in non-uniform metal layer thickness due to uneven deposition around the edges, leading to inferior die quality and potential scrap substrates.
Innovation Solution
A substrate holder with a movable shielding part that protrudes radially to shield areas where patterns are not formed on the resist, and a plating apparatus with an intermediate mask having edge parts that adjust the electric field to prevent excessive metal deposition, ensuring uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrolytic plating is performed on the entire substrate surface, then metal ions are deposited uniformly across most areas, but excessive metal deposition occurs in regions where patterns are not formed on the resist, leading to non-uniform metal layer thickness
Solution Approach 1:
The substrate surface is divided into two distinct regions: a first region where patterns are formed on the resist and a second region where no patterns are formed. This segmentation allows different plating control strategies to be applied to each region, preventing excessive metal deposition in the patternless area while maintaining uniform plating in the patterned area.
Solution Approach 2:
Different quality requirements are applied to different regions of the substrate. The first region (with patterns) receives standard plating treatment, while the second region (without patterns) receives controlled or suppressed plating treatment. This local differentiation ensures that metal layer thickness is uniform across the entire substrate by tailoring the plating process to each region's specific needs.
2Manufacturing precision
If a shielding plate is provided near the energization pin to suppress metal layer thickness, then the plated metal layer thickness at the energization pin position is controlled, but bump heights and wiring thicknesses cannot be suppressed in substrate surfaces where pattern positions are changed
Solution Approach 1:
The shielding plate is made movable rather than fixed, allowing it to be repositioned according to different substrate types and orientations. The moving mechanism enables the shielding plate to dynamically adjust its position to correspond with the second region (patternless area) regardless of how the substrate is arranged, thus maintaining plating precision across various substrate configurations.
Solution Approach 2:
The movable shielding plate system serves multiple functions: it can adapt to different substrate types, different orientations, and different pattern configurations. This universal design allows the same plating apparatus to handle various substrate variations while maintaining consistent metal layer thickness control, eliminating the need for multiple specialized fixtures.
3Adaptability or versatility
If the shielding part is made movable to adapt to different substrate positions, then plating uniformity can be maintained across different substrate orientations, but device complexity increases
Solution Approach 1:
A moving mechanism serves as an intermediary between the fixed plating apparatus and the variable substrate positions. This intermediary component enables the shielding plate to bridge the gap between the stationary equipment and the changing substrate configurations, providing adaptability without requiring complete redesign of the entire plating system.
Solution Approach 2:
The shielding plate is designed with an asymmetric structure where only the necessary portion is made movable, while other parts remain fixed. This selective asymmetry minimizes the complexity of the moving mechanism by limiting mobility to only the regions that require adjustment, thereby reducing overall device complexity while maintaining the necessary adaptability.
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 suppresses the thickness of plated metal layers on areas without patterns, improving the uniformity of the metal layer thickness across the substrate, thereby enhancing die quality and reducing scrap rates.
Implementation Method 1
a shielding part configured to be arranged at the substrate holding part, protrude to an inside of the opening part of the substrate holding part in a radial direction, and shield a part of the substrate
Implementation Method 2
an electrolytic plating method in which miniaturization can be made and in which performance is comparatively stable has been increasingly used for the purpose of forming the wiring and the bump on the substrate
Data Source
AI summary
To suppress thicknesses of a plating film of dies adjacent to a portion in which patterns are not formed on a resist, and improve uniformity of a plated metal layer thickness in a substrate surface. A substrate holder according to the present invention has: a holding surface 57 for holding a substrate; a second holding member 60 configured to have an opening part 63 for exposing the holding surface 57, and to press the substrate placed on the holding surface 57 against the holding surface 57 to thereby hold the substrate; and a shielding plate 65 configured to protrude to an inside of the opening part 63 of the second holding member 60 in a radial direction and to shield a part of the holding surface 57. The shielding plate 65 is configured to be movable along the opening part 63.