Magnetic Head Slider Diffusion Stop Films
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Solution Overview
Problem
Existing magnetic head sliders face resistance variation issues due to inter-film diffusion between the heating and lead portions, leading to increased heat loss and reduced ability to control flying height effectively.
Innovation Solution
Incorporating diffusion stop films, specifically Ta films with a thickness of 5 nm or more, between the terminal and lead portions, and between the lead portion and the lower shield seed film, to suppress resistance variation and maintain intended heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the heating portion and lead portions are formed separately in thin-film fabrication process, then the heater can be manufactured with standard processes, but inter-film diffusion occurs at the bonding regions causing resistance variation and increased heat loss
Solution Approach 1:
A diffusion barrier film is introduced as an intermediary layer between the heating portion and the lead portions. This barrier film prevents inter-film diffusion at the bonding regions while allowing the separate formation of heating and lead portions through standard thin-film fabrication processes. The barrier film thus mediates between the manufacturing convenience of separate formation and the electrical performance requirement of minimizing resistance variation and heat loss.
2Reliability
If the slider is designed with a margin to flying height to prevent disk contact, then reliability is improved, but the distance between magnetic read/write device and magnetic disk cannot be reduced further
Solution Approach 1:
The patent introduces a heater that can dynamically adjust the flying height of the slider on a head-by-head basis. By controlling the heating temperature, the thermal expansion of the slider body can be precisely regulated to achieve the desired flying height. This dynamic adjustment capability allows the system to operate at minimum safe flying heights without requiring excessive design margins, thereby improving both recording density and reliability.
Solution Approach 2:
The flying height is controlled by changing the temperature parameter of the slider through the heater. By adjusting the temperature, the thermal expansion of the slider body changes, which directly affects the flying height. This parameter change approach allows precise control of the distance between the magnetic read/write device and the magnetic disk, enabling reduced flying heights while maintaining reliable operation.
3Ease of manufacture
If resistance of heater increases due to inter-film diffusion, then manufacturing process is simplified, but the heating portion cannot generate intended heat and flying height control becomes impossible
Solution Approach 1:
A diffusion barrier film is introduced as an intermediary layer between the heating portion and the lead portions. This barrier film prevents inter-film diffusion at the bonding regions while allowing the separate formation of heating and lead portions through standard thin-film fabrication processes. The barrier film thus mediates between the manufacturing convenience of separate formation and the electrical performance requirement of minimizing resistance variation and heat loss.
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 reduces resistance variation in the heater, allowing for precise control of flying height and efficient heat generation, enabling the slider to maintain the intended low flying height and high-density recording capabilities.
Implementation Method 1
resistance may increase due to inter-film diffusion where a lead portion is stacked on a lead portion
Implementation Method 2
a think film resistor, arranged between the upper and lower magnetic poles of an inductive thin film magnetic head, is energized, i.e., heated as necessary
Implementation Method 3
heated as necessary in order to project the front ends of the magnetic poles through thermal expansion
Implementation Method 4
The slider runs over the magnetic disk, allowing the magnetic read/write device to read/write magnetic information from/to the magnetic disk. The slider is designed to fly as an air-lubricated bearing by using the wedge film effect of air so as not to cause direct solid contact between the magnetic disk and the slider.
Data Source
AI summary
Embodiments of the present invention help to reduce the resistance variation of the heater provided in order to adjust the flying height of the slider. According to one embodiment, a magnetic head slider has a magnetic read/write device and a heater formed on the trailing end surface of the slider. The heater comprises a heating portion, terminal portions and lead portions. Where a terminal portion overlaps with a lead portion, a diffusion stop film is disposed between them. In addition, a diffusion stop film is disposed between a lead portion and a lower shield seed film (NiFe) under the associated stud. The diffusion stop films and are Ta films with a thickness of 5 nm or preferably at least 10 nm.