Bottom-Up Main Pole Electroplating for Magnetic Write Heads
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Solution Overview
Problem
Existing perpendicular magnetic recording (PMR) write heads often suffer from seamlines in the main pole, which reduce magnetic moment and storage density due to uneven growth during electroplating.
Innovation Solution
A bottom-up main pole electroplating process is employed, involving the deposition of a Ruthenium layer and an insulator layer, followed by an ion-beam-etch process to clean the insulator at the trench bottom, and finally electroplating the main pole from the bottom of the trench, thereby eliminating seamlines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electroplating is used to form the main pole, then the main pole can be manufactured, but seamlines are formed due to uneven growth which reduces magnetic moment and storage density
Solution Approach 1:
The patent inverts the conventional top-down electroplating approach by implementing a bottom-up electroplating process. The trench is filled with electroplating solution from the bottom, allowing the main pole to grow uniformly from the base upward. This inversion eliminates the seamlines that form during conventional top-down plating by ensuring uniform current distribution and material deposition throughout the entire main pole volume, thereby improving both manufacturing precision and magnetic moment.
Solution Approach 2:
The patent applies preliminary action by forming a recessed trench structure in the side shield before electroplating the main pole. This trench preparation creates a controlled cavity that guides the electroplating process, ensuring uniform material deposition and preventing seamline formation. The preliminary trench formation is critical for enabling the bottom-up plating approach to produce a seamless, uniform main pole.
2Ease of manufacture
If seamlines are present in the main pole, then manufacturing is simplified, but storage density is reduced due to uneven growth
Solution Approach 1:
By inverting the electroplating direction from top-down to bottom-up, the patent achieves uniform main pole growth without seamlines. This inversion requires modifying the electroplating process to fill trenches from the bottom, but it eliminates the need for complex post-processing to remove seamlines and ensures maximum material utilization for storage density.
Solution Approach 2:
The patent changes critical process parameters including electroplating solution composition, current density distribution, and temperature control to enable uniform bottom-up growth. These parameter adjustments ensure that the main pole grows uniformly from the bottom, eliminating seamlines while maximizing the magnetic material volume available for storage density.
3Reliability
If bottom-up electroplating is used, then seamlines are eliminated and magnetic moment increases, but the process complexity increases
Solution Approach 1:
The preliminary formation of the recessed trench structure simplifies the overall process by pre-preparing the cavity that guides bottom-up electroplating. This preliminary action eliminates the need for complex real-time process adjustments during electroplating, as the trench geometry naturally directs material flow and current distribution, thereby reducing process complexity while achieving high magnetic moment.
Solution Approach 2:
The patent optimizes electroplating parameters including solution composition, current density, and temperature to enable uniform bottom-up growth. These parameter optimizations simplify the process by ensuring automatic uniform distribution of materials and currents, eliminating the need for complex external control systems while maximizing magnetic moment.
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 eliminates seamlines, increases magnetic moments in the main pole volume, and enhances the overall performance of the PMR write head by improving storage density and magnetic recording efficiency.
Implementation Method 1
performing an ion-beam-etch (IBE) process to clean the insulator at bottom of the trench
Implementation Method 2
electroplating the MP on Ru seed only from the bottom of the trench
Data Source
AI summary
The present embodiments relate to MP electroplating processes that eliminate seamlines using a bottom-up MP electroplating process. The MP electroplating process can include, after disposing the side shield, depositing a Ru layer as a side gap layer. The process can further include depositing an insulator layer. The MP bottom-up electroplating process can further include performing an ion-beam-etch (IBE) process to clean the insulator at bottom of the trench. After resist patterning, the electroplating process can include electroplating the MP on Ru seed only from the bottom of the trench. The seamline in the MP can be eliminated in the bottom-up MP electroplating process.