Mirage-effect-based depth profiling of micromachined silicon structures
TL;DR: In this paper, a noncontact, non-destructive technique for the depth profiling of micromachined structures is presented based on the mirage or optical-beam deflection method of photothermal spectroscopy, an experimental measurement of a 8 μm step in silicon is given by way of illustration.
Abstract: A non-contact, non-destructive technique for the depth profiling of micromachined structures is presented. Based on the mirage or optical-beam deflection method of photothermal spectroscopy, an experimental measurement of a 8 μm step in silicon is given by way of illustration.
Citations
More filters
[...]
TL;DR: In this article, the authors proposed a digitized linear frequency modulated thermal wave imaging (DFMTWI) method for the interface study of the bonded wafers that are frequently used in MEMS and VLSI.
Abstract: Thermography is a whole field, non-contact and non-destructive characterization technique that is widely used for the investigation of sub-surface features in various kinds of solid materials (conductors, semiconductors, insulators and polymers). In this work, a new method is proposed and demonstrated for the interface study of the bonded wafers that are frequently used in MEMS and VLSI. For the demonstration, two oxidized wafers are direct bonded: one plane and the other having anisotropically etched cavities. To observe the effect of annealing on bonding, the bonded pair was annealed at different temperatures for a fixed period, and also for different time periods at a fixed temperature. Compared to conventional passive wave and pulse thermography techniques, the proposed digitized linear frequency modulated thermal wave imaging (DFMTWI) method overcomes certain drawbacks associated with conventional thermal imaging techniques: in comparison to lock-in thermography it requires very less experimentation time whereas in comparison with pulse thermography less peak power heat sources are sufficient. It is further demonstrated that DFMTWI, in principle, is capable of differentiating depths of various cavities, and the thermal phase images can lead to actual depth estimation also.
38 citations
[...]
TL;DR: In this paper, a 2D suspension arm with 2D actuation was developed to provide high-bandwidth data tracking when fully integrated in a hard disk drive environment, which is known as dual-stage actuation, with the added feature of adjusting the flylng height of the head with great precision and accuracy.
Abstract: A novel suspension arm with 2-dimensional actuation has been developed While retaining present technology to give coarse positioning of the head, the arm while making use of embedded piezoelectric materials is intended to provide high-bandwidth data tracking when fully integrated in a hard disk drive environment. This is known as dual-stage actuation. The suspension arm also has the added feature of adjusting the flylng height of the head with great precision and accuracy. The arm developed is tested dynamically and characterised. Specialised closed-loop control algorithms are developed to position and control each dimension of motion independently.
7 citations
[...]
TL;DR: In this paper, a suspension arm is developed which incorporates multi-layer bulk PZT actuators to enable real-time active adjustment of the head flying height with high precision and accuracy while the disk drive is in operation.
Abstract: When a hard disk drive is operated under hostile conditions fluctuations of the head flying height affect data-transfer, eventually leading to complete data-transfer failure. A test facility has been developed to enable data-transfer and their associated failure mechanisms to be characterised. In order to circumvent this problem and to obtain greater control of the head flying height a novel suspension arm has been developed which incorporates multi-layer bulk PZT actuators. This will enable real-time active adjustment of the head flying height with high precision and accuracy, while the disk drive is in operation. The arm developed is tested dynamically and characterised, and specialised closed-loop control algorithms developed to position and control the head above the disk surface.
6 citations
Patent•
[...]
05 Feb 2005
TL;DR: A photothermal recording system has a scanning mirror (21) between excitation laser (11) and object (10) reflecting excitation and measurement beams onto an optical filter (23) reflecting the measurement wavelength only through a focussing lens (27) and mirror (26) so as to view (30) the air above the object.
Abstract: A photothermal recording system has a scanning mirror (21) between excitation laser (11) and object (10) reflecting excitation and measurement (16) beams onto an optical filter (23) reflecting the measurement wavelength only through a focussing lens (27) and mirror (26) so as to view (30) the air above the object. Independent claims are included for the use of the recording system for art objects, handwriting and painting research.
1 citations
[...]
14 Feb 2005
TL;DR: In this article, a tungsten lamp that illuminates a solid material enclosed in a glass container filled with distilled water was used to generate heating of the sample, and a four quadrants position sensor monitored the movement of the spot of the laser using a lock-in amplifier.
Abstract: In this work, a system to perform the measurement of small changes of temperature in solids and liquids using a laser beam deflection is presented. It consists in a tungsten lamp that illuminates a solid material enclosed in a glass container filled with distilled water; generating heating of the sample. The monitoring of the temperature was made using a probe He-Ne laser whose path is altered by the local change in the index of refraction of the water close to the surface of the sample. A four quadrants position sensor monitors the movement of the spot of the laser using a lock-in amplifier. The lamp is modulated using a power circuit driven by the same lock-in amplifier. This configuration allows the study of very small changes in temperature due to the fact that the lock-in detects at the same frequency that drives the circuit of the lamp. In order to show the potential of our system, applications in pulsed and modulated form and for the measurement of thermal diffusivity are presented. The advantages and limitations as well as the possible improvements of our system are discussed.
1 citations
References
More filters
Book•
[...]
31 Dec 1959
TL;DR: In this paper, a classic account describes the known exact solutions of problems of heat flow, with detailed discussion of all the most important boundary value problems, including boundary value maximization.
Abstract: This classic account describes the known exact solutions of problems of heat flow, with detailed discussion of all the most important boundary value problems.
21,797 citations
[...]
TL;DR: The theory for a sensitive spectroscopy based on the photothermal deflection of a laser beam is developed and its implications for imaging and microscopy are given, and the sources of noise are analyzed.
Abstract: The theory for a sensitive spectroscopy based on the photothermal deflection of a laser beam is developed. We consider cw and pulsed cases of both transverse and collinear photothermal deflection spectroscopy for solids, liquids, gases, and thin films. The predictions of the theory are experimentally verified, its implications for imaging and microscopy are given, and the sources of noise are analyzed. The sensitivity and versatility of photothermal deflection spectroscopy are compared with thermal lensing and photoacoustic spectroscopy.
1,228 citations
[...]
TL;DR: In this paper, a new thermo-optical method based on the sensitive detection of thermal gradients adjacent to heated sample surfaces is described, and room and low-temperature experiments are performed using this technique, and its advantages over different methods are discussed.
Abstract: A new thermo‐optical method based on the sensitive detection of thermal gradients adjacent to heated sample surfaces is described. Room‐ and low‐temperature experiments were performed using this technique, and its advantages over different methods are discussed.
660 citations
[...]
TL;DR: In this article, a theory of optical beam deflection near a heated surface was introduced as a method of photothermal spectroscopy and applied to the measurement of thermal diffusivity of gases.
Abstract: Optical beam deflection near a heated surface was recently introduced as a method of photothermal spectroscopy. Photothermal spectroscopy (PTS) is closely related to photoacoustic spectroscopy (PAS) in its ability to measure optical properties of opaque solids and liquids. This paper develops a theory of this effect and compares this theory with extensive experimental observations. Both are in excellent agreement. The relationship between this form of PTS and PAS is explicitly developed. Applications to the measurement of thermal diffusivity of gases is described.
309 citations
[...]
TL;DR: In this paper, the authors describe a new design for a mirage cell which is much more compact than the previously described setup and whose sensitivity has been improved by an order of magnitude.
Abstract: We describe a new design for a mirage cell which is much more compact than the previously described setup and whose sensitivity has been improved by an order of magnitude. This cell has been successfully coupled to Fourier transform infrared spectrometers, visible spectrometers, and a thermal wave imaging setup.
52 citations
Related Papers (5)
[...]