Semiconductor device manufacturing: process – Bonding of plural semiconductor substrates – Thinning of semiconductor substrate
Reexamination Certificate
2000-11-30
2003-10-28
Elms, Richard (Department: 2824)
Semiconductor device manufacturing: process
Bonding of plural semiconductor substrates
Thinning of semiconductor substrate
C438S458000, C438S455000, C257S723000
Reexamination Certificate
active
06638836
ABSTRACT:
TECHNICAL FIELD
The present invention regards a process for manufacturing a group comprising at least two elements, one whereof includes an encapsulated micro-integrated structure, and a thereby obtained group. In particular, the invention may be advantageously applied for assembling a microactuator, an integrated device including microactuator control circuitry and a head in a hard-disk read/write unit with double micrometric actuation.
BACKGROUND OF THE INVENTION
As is known, hard disks are the most widely used data-storage medium; consequently, they are produced in very large volumes, and the maximum data-storage density increases from one year to the next. Hard disks are read and written by actuator devices, the general structure of which is shown in
FIGS. 1 and 2
and is described hereinafter.
In particular,
FIG. 1
shows a known actuator device
1
of the rotary type comprising a motor
2
(also called “voice coil motor”) fixed to a support body, generally called “E-block” because of its E-like shape in side view (see FIG.
2
). The support body
3
has a plurality of arms
4
, each of which carries a suspension
5
including a cantilevered lamina. At its end not fixed to the support body
3
, each suspension
5
carries a R/W transducer
6
for reading/writing, arranged (in an operative condition) facing a surface of a hard disk
7
so as to perform roll and pitch movements and to follow the surface of the hard disk
7
. To this end, the R/W transducer
6
(also referred to as slider) is fixed to a joint, called gimbal or flexure
8
, generally formed from the suspension
5
and comprising, for example, a rectangular plate
8
a
cut on three and a half sides starting from the lamina of the suspension
5
, and having a portion
8
b
connected to the suspension
5
and allowing flexure of the plate
8
a
under the weight of the slider
6
(see
FIG. 2A
)
In order to increase the data storage density, it has already been proposed to use a double actuation stage, with a first, rougher actuation stage including the motor
2
moving the assembly formed by the support body
3
, the suspension
5
and the R/W slider
6
through the hard disk
7
during a coarse search for the track, and a second actuation stage performing a finer control of position of the slider
6
during tracking. According to a known solution, the second actuation stage comprises a microactuator
10
arranged between the gimbal
8
and the slider
6
, as may be seen in
FIG. 3
, which shows, in exploded view, the end of the suspension
5
, the gimbal
8
, the slider
6
, and the microactuator
10
, in this case, of the rotary type. The microactuator
10
is controlled by a signal supplied by control electronics on the basis of a tracking error.
At present, the circuit for pre-amplificating the signal picked up by the slider
6
is arranged on the board, or at most on the end of the support body
3
, while the microactuator controlling circuitry is integrated with the microactuator. This integration is made possible by silicon microprocessing techniques, such as epitaxial microprocessing or metal electroplating.
The above-mentioned technologies make it difficult, if not impossible, to obtain a group comprising the microactuator-controlling circuitry, the microactuator, the slider, and the pre-amplifying circuit on a same wafer.
In case of epitaxial microprocessing, there is a dimensional incompatibility between the microactuator and the pre-amplification circuit. This incompatibility is due to the fact that the minimum photolithographic dimension of the microactuator is of the order of 1 &mgr;m; instead, because of the high operating frequencies, the pre-amplification circuit requires an extreme photolithographic process not exceeding 0.35 &mgr;m. The difference between the minimum photolithographic dimensions thus renders integration of the two devices on the same technological platform not very convenient
The metal electroplating technique makes it possible to obtain mechanical structures on the circuitry, but presents certain drawbacks. In fact, it is not possible to effectively protect the micromechanical structures from contamination caused by particles present in the hard-disk driver; assembly of the slider on the microactuator proves difficult; in addition, electrical isolation of the signals supplied by the head from the signals controlling the microactuator is difficult.
SUMMARY OF THE INVENTION
An embodiment of the present invention is a process for assembling a micromechanical structure, in particular a microactuator, on a supporting element, in particular an integrated device containing the circuitry, that protects the micromechanical structure at least during assembly.
REFERENCES:
patent: 4943750 (1990-07-01), Howe et al.
patent: 5025346 (1991-06-01), Tang et al.
patent: 5521778 (1996-05-01), Boutaghou et al.
patent: 5539596 (1996-07-01), Fontana et al.
patent: 5805375 (1998-09-01), Fan et al.
patent: 5920441 (1999-07-01), Cunningham et al.
patent: 5959808 (1999-09-01), Fan et al.
patent: 6483671 (2002-11-01), Vigna et al.
patent: 6521513 (2003-02-01), Lebens et al.
patent: 913921 (1999-05-01), None
“Preamp Chip on Actuator Arm Boosts Signal Margin”, Data Storage, Feb. 18, 1998.
Woods, D., “Preamp on the load beam delivers more performance”, Data Storage, Jun. 21-23, 1999.
Zhang, L, et al., “Lost Data: How a Little Dirt Can Do a Lot of Damage”, Data Storage, Mar. 15-20, 1999.
Imamura, T. et al., “Transverse Mode Electrostatic Micoactuator For MEMS-Based HDD Slider”, Proceedings of the Annual International Workshop on Micro Electro Mechanical Systems, IEEE, Workshop 9:216-221, Feb. 11, 1996.
Fan, L.S. et al., “Magnetic Recording Head Positioning at Very High Track Densities Using a Microactuator-Based Two Stage Servo System”, IEEE Transactions on Industrial Electronics, 42(3):222-233, Jun. 1, 1995.
Hirano, T. et al., “Micro-Actuator for Tera-Storage”, IEEE:441-446, 1999.
Lee, A.P. et al., Polysilicon Micro Vibromotors, Proceedings of the Workshop on Micro Electro Mechanical Systems, IEEE, Workshop 5:177-182, Feb. 4, 1992.
Gianchandani, Y. et al., “Batch Fabrication and Assembly of Micromotor-Driven Mechanisms with Multi-Level Linkages”, Proceedings of the Workshop on Micro Electro Mechanical Systems, IEEE, Workshop 5:141-146, Feb. 4, 1992.
Tang, W.C. et al., “Laterally Driven Polysilicon Resonant Microstructures”, Sensors and Actuators, Elsevier Sequoia, 20(½):25-32, Nov. 15, 1989.
Alessandri Alberto
Murari Bruno
Ratti Francesco
Sassolini Simone
Vigna Benedetto
Elms Richard
Iannucci Robert
Jorgenson Lisa K.
Seed IP Law Group PLLC
Smith Brad
LandOfFree
Process for manufacturing a group comprising at least two... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for manufacturing a group comprising at least two..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for manufacturing a group comprising at least two... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3122277