Antanas Daugela

In-Situ Quantitative Integrated Tribo-SPM Nano-Micro-Metrology

A novel quantitative nano/micro-tribometer with integrated SPM and optical microscope imaging has been developed to characterize numerous physical and mechanical properties of liquid and solid thin films and coatings, with in-situ monitoring their changes during micro and nano indentation, scratching, reciprocating, rotating and other tribology tests. Both the materials properties and surface topography can be assessed periodically during the tests.Copyright

Entropy-Based Multi-Resolution Head/Media Contact Detection for Hard Disk Drive

A double entropy-based characterization methodology is proposed for the hard disk drive (HDD) head/media contact detection operation. At first, signal entropy minimization is used to extract the head/media modulation-induced proximity sensor response converting it into four compact and descriptive parameters derived from an adaptive discrete wavelet transform (ADWT). The second stage and the head/media contact decision process involve statistical screening of moving entropies derived from the four ADWT parameters. This double entropy methodology provides significantly improved head/media contact decision fidelity and targets modern HDD products.

Low SNR Signal Processing for Head Media Contact Detection in HDD

The methodology for processing grossly undersampled HDD position error signal (PES) is proposed to improve the head-disk contact detection process. The proposed method is a combination of compressive sampling (CS) and adaptive discrete wavelet transform (ADWT) techniques. Here, CS is employed to reconstruct the PES information from very few revolutions of data while ADWT is utilized for extracting head-disk interface (HDI) modulation changes during thermal protrusion of the read/write element.Copyright

DLC Coatings Characterization on HDD Recording Heads

New magnetic storage technology enhancements are being introduced into the HDD products to facilitate lower head media spacing and reliability. Recently, advanced components such as thermal protrusion devices, Head Disc Interface (HDI) proximity sensors, complex self-compensating AAB designs have been integrated into the recording heads. Component development and product integration teams evaluate performance of these critical head disc interfaces for tribological robustness. New HDI components could potentially bring new HDI wear mechanisms that occur under specific thermo-mechanical conditions. Characterization of recording head DLC overcoat nanoscale wear performance has always been a challenge. Historically, nano-wear tests evolved in conjunction with advances in Scanning Probe Microscopy (SPM) techniques [1] and wear resistive tools [2] like diamond tip cantilevers. Here, by controlling SPM, contact force specified wear patterns can be obtained in contact mode or dynamic mode. Decisions on DLC wear resistance can be made qualitatively by evaluating wear mark topographies.Copyright

Multi-Resolution HDD Contact Detection Technique for Low SNR Applications

A quick and reliable active flying height calibration is critical in today’s hard disc drive short product development and high volume production cycles. In addition to the servo signals, passive HDI acoustic and proximity monitoring techniques are tracking equilibrium of the head gimble assembly and air bearing modes. Passive acoustic HDI monitoring had been proven to be capable in active head protrusion detection applications [1] where derived passive and active Air Bearing flying profiles help to set active flying clearance. With enhanced sensitivity, passive acoustic techniques such as AE can detect embedded particles [2]. The drawback of this technique is that noisy HDD environment causes loss of detectability of the useful AE signal [3]. Special attention has to be paid for extracting desirable HDI information. On the other hand, recording head based proximity probes are immune to torsional HDI modes and operate on pitch mode induced modulation. Advanced HDD today uses a combination of recording head based proximity sensors that are designed to sense HDI modulation at close proximity to the disc. It has to be pointed out that interpretation of proximity probe contact signatures always has been challenging.Copyright

TRIBOLOGICAL PROCESS CHARACTERIZATION WITH IN-SITU QUANTITATIVE NANO-SCALE METROLOGY

A novel quantitative nano+micro-tribometer with integrated nanoindenter, SPM and optical microscope imaging has been used to characterize mechanical properties of Cu coated Si wafers at various test stages. A 2D Finite Element Model was developed to study changes on workhardened contacts assessed via nanoindentation experiments.Copyright

Integrated Multi-Sensor Tribo-SPM Nano+Micro Tribo-Metrology

A novel quantitative nano+micro tribometer with integrated AFM and optical microscope has been utilized to characterize tribological and mechanical properties of liquid and solid thin films and coatings, with in-situ monitoring their changes during micro and nano indentation, scratching, reciprocating, rotating and other tribology tests.© 2005 ASME

In-Situ Tribological Properties Monitoring and Chemical Mechanical Characterization of Planarization Process

For faster signal propagation in integrated circuits, new materials with lower dielectric constant (low-k) values are required with copper metal lines. Although integration of low-k materials (k<3.0) has been demonstrated, but ultra low-k materials possess many challenges due to their poor mechanical integrity and weak adhesion to other interconnects. During chemical mechanical planarization (CMP) generation of several defects including delamination of low-k materials is severe problem in the integration of these materials. Different slurries and pad introduces different levels of defect and also batch-to-batch variation in consumables is often makes process more difficult. In this study we have investigated the tribological properties of CMP pad and wafer interface while monitoring coefficient of friction and acoustic emission data. Signals are analyzed in order to online defect monitoring, batch-to-batch consumable variations and different consumables effects.Copyright