Shallow Laminated Hard Mask Stencil for Magnetic Read Sensor Fabrication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for forming magnetic read heads struggle to achieve the necessary narrow track widths required for increased data storage density, as existing mask stencils lack sufficient control over both track width and height, leading to inefficiencies in sensor fabrication.
Innovation Solution
The use of a four-layered or three-layered hard mask stencil in conjunction with a two-step chemical mechanical planarization (CMP) process and reactive ion etch (RIE) techniques to form a shallow and narrow hard mask stencil, allowing for precise control over the sensor structure's dimensions and shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mask stencils are used for forming read heads, then the fabrication process is simpler, but the track width and height uniformity are insufficient for increased data storage density
Solution Approach 1:
The mask stencil is divided into multiple discrete layers (typically three to five layers including hard mask and photoresist layers), each serving specific functions. This segmentation allows independent optimization of each layer's thickness and material properties, achieving superior track width uniformity (±2nm) and height control that cannot be achieved with conventional single-layer masks.
Solution Approach 2:
The multi-layer mask stencil employs composite material structures combining different materials with complementary properties - such as silicon nitride, silicon oxide, diamond-like carbon, and various photoresist materials. Each material is selected for its specific etch selectivity, mechanical properties, and lithographic performance, enabling precise dimensional control while managing the increased structural complexity.
2Manufacturing precision
If multi-layer hard mask stencil is implemented, then dimensional control is improved, but the fabrication process becomes more complex
Solution Approach 1:
The mask layers are deposited and patterned in advance with precisely controlled thicknesses before the actual sensor fabrication begins. The multi-layer structure is pre-configured with specific thickness ratios and material compositions that predetermine the final sensor dimensions, allowing height uniformity to be established early in the process and maintained through subsequent steps.
Solution Approach 2:
The fabrication process utilizes controlled changes in deposition parameters (thickness, composition), etch parameters (selectivity, rate), and lithographic parameters (exposure dose, focus) across different layers. By systematically adjusting these parameters for each layer, the process achieves superior height uniformity while managing the complexity through standardized parameter sets that can be replicated and optimized.
3Area of moving object
If narrower track widths are fabricated, then data storage density increases, but the control over track dimensions becomes more difficult
Solution Approach 1:
The solution transitions from controlling only the lateral dimension (track width) to controlling both lateral and vertical dimensions simultaneously through the multi-layer mask structure. By adding the vertical dimension (multiple layers with controlled thicknesses), the process gains additional degrees of freedom to achieve narrow track widths (below 50nm) while maintaining precise dimensional control through independent optimization of each layer's contribution to the final geometry.
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 enables the fabrication of magnetic read heads with improved track width and height uniformity, enhancing data storage density and sensor performance by providing better control over the mask stencil's dimensions and shape.
Implementation Method 1
The sensor structure is formed with a two-step chemical mechanical planarization (CMP) process
Implementation Method 2
a series of photolithographic processes and reactive ion etch (RIE) processes are then conducted to form a mask stencil above the sensor layers. An ion milling process then removes unmasked portions of the sensor layers
Data Source
AI summary
The present invention generally relates to methods for forming a sensor structure utilizing a shallow and narrow hard mask stencil. In one embodiment, a sensor structure is formed by utilizing a four-layered hard mask stencil. The four-layered hard mask stencil includes a first mask layer, a second mask layer disposed over the first hard mask, a third mask layer disposed over the second mask layer, and a forth mask layer disposed over the third mask layer. In another embodiment, a sensor structure is formed by utilizing a three-layered hard mask stencil. The three-layered hard mask stencil includes a first mask layer, a second mask layer disposed over the first mask layer, and a third mask layer disposed over the second mask layer. The sensor structure is formed with a two-step chemical mechanical planarization (CMP) process.