Through Hole Electrode Substrate Pulse Current Plating
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Solution Overview
Problem
Current through hole electrode substrates face challenges in achieving high-density packaging and efficient electrical conductivity between stacked LSI chips, with existing methods failing to ensure reliable conductivity and optimal electrical properties in the conductive parts.
Innovation Solution
A method of manufacturing through hole electrode substrates involves forming through holes in a substrate, depositing a seed layer, and using electrolytic plating with pulse current to fill the holes with metal, optimizing current density and voltage polarity to enhance conductivity and reduce voids, resulting in improved electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrolytic plating with direct current is used to fill through holes with conductive material, then the through holes can be filled, but voids form in the conductive part and electrical properties deteriorate
Solution Approach 1:
The patent applies periodic reversal of current polarity during electrolytic plating. The current direction is alternately reversed at predetermined intervals, causing metal ions to deposit uniformly from both directions and preventing void formation in the center of through holes. This periodic action transforms the continuous direct current process into a pulsating bidirectional plating process, eliminating the harmful voids while maintaining reliable conductivity.
2Reliability
If electrolytic plating is used to form conductive parts in through holes, then conductivity can be achieved, but electrical properties such as resistance values are not optimized
Solution Approach 1:
The periodic reversal of current polarity ensures uniform metal deposition throughout the through hole, creating a dense conductive path with minimized resistance. The bidirectional plating process eliminates voids and ensures complete filling, resulting in optimized electrical properties that unidirectional plating cannot achieve.
3Ease of manufacture
If conventional electrolytic plating methods are used, then through holes can be filled with metal, but uniform metal layer growth is not achieved
Solution Approach 1:
The patent employs periodic current reversal to achieve uniform metal layer growth in through holes. By alternating the current direction, metal ions are deposited from both ends simultaneously, ensuring even distribution and thickness throughout the conductive path. This eliminates the non-uniform growth that occurs in conventional unidirectional plating methods.
4Ease of manufacture
If direct current electrolytic plating is applied continuously, then through holes can be filled, but current density cannot be optimized for different stages of filling
Solution Approach 1:
The periodic current reversal system allows dynamic control of current density at different stages of the filling process. By adjusting the reversal frequency and duration, the process can accommodate varying current density requirements during different phases of through hole filling, optimizing deposition rates and preventing defects while maintaining manufacturing simplicity.
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 improved electrical properties by increasing the crystal grain diameter of the metal material, reducing resistance values, and ensuring uniform metal layer growth, thereby enhancing the conductivity and manufacturing efficiency of the through hole electrode substrates.
Implementation Method 1
forming a metal layer having a cap shape on a bottom part of the through hole on a surface on which the seed layer is formed by an electrolytic plating method supplying direct current to the seed layer for a first time period and filling a metal material into the plurality of through holes by an electrolytic plating method supplying a pulse current to the seed layer and the metal layer
Implementation Method 2
The electrolytic plating method may be performed by periodically applying a plus voltage and a minus voltage to the seed film
Data Source
AI summary
To provide a method of manufacturing a through hole electrode substrate which comprises forming a plurality of through holes passing through the front and back of a wafer-shaped substrate, forming an insulation film on a surface of the substrate and the though hole, forming a seed layer from a metal on at least one side of the substrate and/or the through hole, forming a metal layer having a cap shape on a bottom part of the through hole on a surface on which the seed layer is formed by an electrolytic plating method supplying direct current to the seed layer for a first time period, and filling a metal material into the plurality of through holes by an electrolytic plating method supplying a pulse current to the seed layer and the metal layer.