Through Electrode Formation via Depth-Direction Electroplating
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Solution Overview
Problem
The existing methods for forming through electrodes in silicon or glass substrates face challenges such as void generation and increased process costs due to high aspect ratios and substrate warpage, especially when forming thin substrates.
Innovation Solution
A method involving blocking the opening of a through hole with a current supply path and using electroplating in the depth direction to form a through electrode, which includes temporarily adhering a conductive substrate and removing it after the electrode is formed, and optionally using a second metal with a lower melting point to facilitate the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lateral plating is used to form through electrodes in high aspect ratio holes, then the through electrode can be formed, but voids are easily generated due to the high aspect ratio and deep hole depth
Solution Approach 1:
The patent inverts the conventional lateral plating approach by performing electroplating in the depth direction from the blocked opening toward the bottom of the through hole. This inversion of the plating direction allows metal to be deposited uniformly along the hole depth without the void formation problems associated with lateral plating in high aspect ratio structures
Solution Approach 2:
The patent applies preliminary action by blocking the opening of the through hole with a conductive substrate before performing the electroplating. This preliminary blocking structure serves as both a mask and a current supply path, enabling the electroplating to proceed uniformly from the blocked opening toward the bottom of the hole without void formation
2Ease of manufacture
If a thick plating film is formed on the substrate surface to block the through hole opening, then the through hole can be blocked, but substrate warpage occurs and process cost increases
Solution Approach 1:
The patent uses a conductive substrate as an intermediary element that serves multiple functions: it blocks the through hole opening, provides a current supply path for electroplating, and can be temporarily adhered and removed without causing substrate warpage. This intermediary approach replaces the conventional thick plating film method
Solution Approach 2:
The patent changes the physical state and properties by using a conductive substrate with removable adhesive instead of forming a thick plating film. This parameter change allows the blocking function to be achieved without the warpage issues associated with thick plating, and the adhesive can be removed after serving its purpose
3Productivity
If conventional methods are used to form through electrodes in thin substrates, then the process can be completed, but substrate warpage occurs and reliability decreases
Solution Approach 1:
The conductive substrate acts as a mediator that supports the thin substrate during the electroplating process, preventing warpage. The temporary adhesive allows the conductive substrate to be adhered, provide support during processing, and then removed without damaging the thin substrate
Solution Approach 2:
The conductive substrate is preliminarily adhered to the thin substrate before the electroplating process to provide mechanical support and prevent warpage during processing. This preliminary support structure is removed after the electroplating is complete, leaving the thin substrate intact without warpage
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 approach allows for the formation of void-free through electrodes in thin substrates at a lower cost, improving yield and reliability by preventing substrate warpage and eliminating the need for thick plating layers.
Implementation Method 1
disposing a first metal in the through hole to form the through electrode by electroplating, in a depth direction of the through hole, using the current supply path
Data Source
AI summary
There is provided a method for manufacturing a wiring substrate with a through electrode, the method including providing a device substrate having a through hole, an opening of the through hole being blocked by a current supply path and the wiring substrate including the device substrate as a core layer with the through electrode; and disposing a first metal in the through hole to form the through electrode by electroplating, in a depth direction of the through hole, using the current supply path.