1500-D Series

Ultra-High Resolution &
Ultra-High Sensitivity Thin Film Measurement System
for Hard Disks

The n&k 1500-D utilizes raw Reflectance (R) data to determine the optical properties (n and k) and thicknesses of thin films, in particular diamond-like carbon (DLC) and magnetic layers, comprising hard disks. This manual load system with automated stage is designed to handle all sizes of hard disks. With a 1mm spot size, the raw reflectance data is acquired over a wide wavelength range (190 – 1000nm) with optimized signal-to-noise ratio, resulting in the capability of the n&k 1500-D to accurately measure thickness and determine Hydrogen and Nitrogen content of increasingly thinner DLC, independent of any variations in the mag layers.

Disk Drive Platters

On the software end, a valid physical model utilizes the Forouhi-Bloomer Dispersion Equation for n and k, to analyze raw Reflectance data. The Forouhi-Bloomer (FB) model describes the Refractive Index, n, and the Extinction Coefficient, k, as functions of wavelength, λ, and was derived based on first principles quantum mechanics. The scientific derivations of the FB model were originally published in 1986 and 1988, and a related patent was subsequently granted in 1990.

Manual-load Optical Metrology System With Automated Stage
For Data Storage Applications
Involving Ultra-thin DLC And Thin Mag Layers

1500-D Series General Specifications

  • Optimized Reflectance (R) Data
    • Wavelength Range: 190 – 1000nm in 1nm intervals
    • 1mm Spot Size
  • Handles all sizes of hard disks
  • Automated X-Y Stage
  • Based on Patented Reflective Optics that Optimizes the Signal-to-Noise Ratio
  • Strong Sensitivity to Sub-Nanometer Structural and/or Material Variations
  • Thin Film Measurements
    • DLC Thickness, n and k (from 190 – 1000 mm)
    • %H, %N in DLC
    • Thicknesses of Mag Layers, n and k (from 190 – 1000 mm)
  • Variations of the Mag Layers does not affect the accuracy of the DLC Measurements
  • No Re-Alignment Issues Upon Light Bulb Replacement
  • Easy to Maintain and Service

Thin Film Application Examples

DLC Thickness Measurement Demonstrating Angstrom Level Accuracy
DLC: Layer (10)
Metallic Layer (9)
Metallic Layer (8)
Metallic Layer (1-7)
Metallic Layer 8
Metallic Layer 9
Layer 10 (DLC)

n and k spectra of the top three layers of the film structure

DLC: Layer (10)
Metallic Layer (9)
Metallic Layer (8)
Metallic Layer (1-7)
NiP Substrate
Metallic Layer 8

Mean Thickness: 62.8 Å
Standard Dev.: 3.04 Å

Metallic Layer 9

Mean Thickness: 52.4 Å
Standard Dev.: 1.66 Å

Layer 10 (DLC)

Mean Thickness: 50.0 Å
Standard Dev.: 1.15 Å

Carbon: n and k Spectra (190 - 1000nm)
Co - Oxide: n and k Spectra (190 - 1000nm)
Co - Alloy: n and k Spectra (190 - 1000nm)
Co - Oxide: n and k Spectra (190 - 1000nm)

Note: Based on Customer’s input, Ru and SUL thicknesses were kept fixed at 195Å & 1000Å

n&k Technology 1500-D Series Markets

Our products will be your eyes on the Nano scale, to ensure your IC’s and products have the highest yields.

Data Storage

Cloud storage, desktop PC’s, and laptops continue to grow demand for data storage peripherals. Our products are viable metrology solutions for both Head processing and Disk Media processing.