Active solid-state devices (e.g. – transistors – solid-state diode – Responsive to non-electrical signal – Physical deformation
Reexamination Certificate
1998-10-28
2001-03-06
Smith, Matthew (Department: 2825)
Active solid-state devices (e.g., transistors, solid-state diode
Responsive to non-electrical signal
Physical deformation
C257S420000, C257S421000, C257S426000, C310S309000, C361S207000
Reexamination Certificate
active
06198145
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method for manufacturing a semiconductor material integrated microactuator, in particular for a hard disc mobile read/write head, and the microactuator obtained thereby.
BACKGROUND OF THE INVENTION
In hard disc read/write devices of a known type, the read/write heads are glued directly to the end of a steel suspension unit, which allows the head to be moved at a predetermined distance from the disc, currently approximately 30 nm.
To obtain more accurate and finer head position control, it has been proposed to arrange a microactuator between the head and the steel suspension unit. This microactuator must impart to the head (which generally has a weight of a few milligrams) an acceleration that is 20-30 times that of gravity; this means that the microactuator should be able to exert a force of approximately tenths of milliNewtons to be suitable for this purpose.
The microactuator must also be very flexible in a plane parallel to the disc, as well as being highly resistant in a perpendicular direction, to support the weight of the head (currently 1.5 mg), and to oppose the pressure generated during operation. In fact, as the disc rotates, a pressure profile is generated on the surface of the latter which tends to move the head away from the disc. On the other hand, if the head is moved away from the disc further than predetermined limits, the signal is so attenuated to make it impossible to read/write data; as a result, to maintain the required position, the suspension unit must currently exert on the head a direct force of approximately 2-3 g towards the disc.
The integrated microactuators available to date use actuation forces of electromagnetic and electrostatic nature.
Microactuators using electromagnetic forces are disadvantageous, because they require depositing of magnetic materials that are not commonly used in the microelectronics industry. Because the data on the disc is stored by magnetizing the disc surface, interference effects are possible between the data recording on the disc and the actuation mechanism. Furthermore, structures that use magnetic forces are more difficult to scale than those that use electrostatic forces.
Microactuators which use electrostatic type forces are preferable, both as regards the possibility of manufacturing the microactuators using conventional microelectronics production techniques, and because of the compatibility with the processes of reading and writing data on the disc.
Various solutions have been proposed for producing microactuators of an electrostatic type; according to a first solution, the elements of the actuator are produced by surface micromachining, i.e., by using surface layers deposited on a wafer of semiconductor material, or by electro-galvanic growth, or through ad hoc processes that differ from those normally used in microelectronics.
The technique of surface micromachining has the disadvantage that it does not allow manufacturing of structures having the above-described requirements, because the thinness of the polysilicon films which can be produced by common deposition techniques make the final structures not sufficiently rigid in a direction perpendicular to the disc; in addition, they cannot impart sufficient accelerating electrostatic force to the head, and are unstable because the edge effects are higher than the surface effects, and the system is less linear.
The system using galvanic growth, in which layers of metallic material are used, has the disadvantage that it has worse mechanical characteristics (in particular with reference to the yield strength &sgr;, and is subject to hysteresis (whereas silicon does not have hysteresis); on the other hand the solution which uses ad hoc processes is difficult to industrialize, and has low yields.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a method and a microactuator which are free from the disadvantages of the solutions available to date.
According to the present invention, a method is provided for manufacturing a semiconductor material integrated microactuator, in particular for a hard disc mobile read/write head, and the microactuator obtained thereby.
REFERENCES:
patent: 3789378 (1974-01-01), Bonzano et al.
patent: 5025346 (1991-06-01), Tang et al.
patent: 5151763 (1992-09-01), Marek et al.
patent: 5216631 (1993-06-01), Sliwa, Jr.
patent: 5233213 (1993-08-01), Marek
patent: 5428259 (1995-06-01), Suzuki
patent: 5438469 (1995-08-01), Rudi
patent: 5477097 (1995-12-01), Matsumoto
patent: 5521778 (1996-05-01), Boutaghou et al.
patent: 5631514 (1997-05-01), Garcia et al.
patent: 5657188 (1997-08-01), Jurgenson et al.
patent: 0 482 205 A1 (1992-04-01), None
patent: 0 533 095 A2 (1993-03-01), None
patent: 0 578 228 A2 (1994-01-01), None
patent: 0 578 228 A3 (1994-01-01), None
patent: 0 613 124 A2 (1994-08-01), None
patent: 0 840 291 A2 (1998-05-01), None
patent: 2 296 297 (1976-07-01), None
patent: 7-177773 (1995-07-01), None
patent: WO 93/21536 (1993-10-01), None
patent: WO 95/34943 (1995-12-01), None
Horsley et al., “Angular micropositioner for disk drives”, MEMS '97, Proceedings, IEEE Annual International Workshop, Jan. 26-30, 1997, pp. 454-459.
Gianchandani et al., “Batch Fabrication and Assembly of Micromotor-Driven Mechanisms With Multi-Level Linkages,”Micro Electro Mechanical Systems,IEEE, pp. 141-146, 1992.
Lee et al., “Polysilicon Micro Vibromotors,”Micro Electro Mechanical Systems,IEEE, pp. 177-182, Feb. 4-7, 1992.
Fujita et al., “Position Control Of An Electrostatic Linear Actuator Using Rolling Motion,”Mechatronics,vol. 2, No. 5, pp. 495-502, Oct., 1992.
Fan et al., “Magnetic Recording Head Positioning at Very High Track Densities Using a Microactuator-Based, Two-Stage Servo System,”Transactions on Industrial Electronics,IEEE, 42(3):222-233, Jun. 1995.
Moesner et al, “Electrostatic Devices For Particle Micro-Handling,” IEEE, pp. 1302-1309, 1995.
Imamura et al., “Transverse Mode Electrostatic Microactuator For MEMS-Based HDD Slider,”IEEE,pp. 216-221, 1996.
Horsley et al., “Angular Micropositioner For Disk Drives,”IEEE MEMS '97 WorkshopNagoya, Japan.
Pannu et al., “Accelerometer Feedforward Servo For Disk Drives.” Presented at theAdvanced Intelligent Mechatronics-International Conference,Tokyo, Japan, Jun. 1997.
Aggarwal, “Design and Control of Micro-Actuators For High Density Disk Drives”,Thesis—Graduate Division—University of California at Berkeley,May 1997.
Aggarwal et al., “Micro-Actuators For High Density Disk Drives,”American Control Conference,Jun. 4-6, 1997.
Peter Mee et al, “Only Clean Drives Are Good Drives,”Data Storage,pp. 77-80, Sep., 1997.
Tang et al., “Laterally Driven Polysilicon Resonant Microstructures”,Sensors and Actuators20(½):25-32, 1989.
Starr, “Squeeze-Film Damping in Solid-State Accelerometers,”IEEE Solid-State Sensor and Actuator Workshop, pp. 44-47, Jun. 1990.
Zhang et al., “Viscous Air Damping in Laterally Driven Microresonators,”IEEE WorkshopNo. 7, pp. 199-204, Jan. 25, 1994.
Veijola et al., “Model for Gas Film Damping in a Silicon Accelerometer,”1997 International Conference on Solid-State Sensors and Actuators,pp. 1097-1100, Jun. 16-19, 1997.
Ferrari Paolo
Vigna Benedetto
Galanthay Theodore E.
Iannucci Robert
Malsawma Lex H.
Seed IP Law Group PLLC
Smith Matthew
LandOfFree
Method for manufacturing a semiconductor material integrated... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for manufacturing a semiconductor material integrated..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for manufacturing a semiconductor material integrated... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2544489