Chemistry: electrical and wave energy – Processes and products – Coating – forming or etching by sputtering
Reexamination Certificate
2001-11-30
2003-11-04
VerSteeg, Steven H. (Department: 1753)
Chemistry: electrical and wave energy
Processes and products
Coating, forming or etching by sputtering
C204S192320, C204S298110, C204S298250, C204S298260, C204S298280, C427S128000, C427S131000, C427S132000, C427S129000, C427S130000, C118S719000, C118S600000, C118S504000, C216S022000, C134S001000, C134S011000
Reexamination Certificate
active
06641703
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims the priority of JP 2000-365696, filed in Japan on Nov. 30, 2000, the entire contents of which are hereby incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to a magnetic multi-layer film manufacturing apparatus.
BACKGROUND OF THE INVENTION
In the description of the background of the present invention that follows reference is made to certain structures and methods, however, such references should not necessarily be construed as an admission that these structures and methods qualify as prior art under the applicable statutory provisions. Applicants reserve the right to demonstrate that any of the referenced subject matter does not constitute prior art with regard to the present invention.
Magnetoresistive effect-type magnetic heads, which constitute playback magnetic heads in which a magnetoresistive effect element is employed as a magnet-sensitive element, have actual application as playback parts for hard disk drives and the like. TMR elements have begun to be employed in recent years as magnetoresistive effect elements used in magnetoresistive effect-type magnetic heads. TMR elements are elements that use a TMR (Tunneling Magnetoresistive) effect. The TMR effect is a magnetoresistive effect produced by tunnel junctions in which an insulating body is enclosed by a strong magnetic body. Compared to elements of the prior art that use an AMR (Anisotropic Magnetoresistive) effect and GMR (Giant Magnetoresistive) effect, TMR elements are advantageous in that they have a large MR ratio. The MR ratio thereof is 30 to 50%.
The films from which the above-described TMR elements are configured comprise, specifically, a multi-layer film structure in which a first soft magnetic layer, an insulating layer, a second soft magnetic layer, and an antiferromagnetic layer are deposited successively. In these TMR elements, film deposition is performed by the use of individual sputtering of the respective plurality of magnetic films, and the film formation of the insulating layer is performed using a metal oxide reaction.
As is described above, the conventional magnetic multi-layer film manufacturing apparatus, in which film layers of the multi-layer film are successively deposited on a substrate, performs continuous multi-layer film deposition.
FIG. 6
shows a hitherto used representative sputtering film forming apparatus for heads. In this sputtering film depositing apparatus, a comparatively large single film-depositing chamber
103
is provided in the perimeter of a transferring chamber
102
which includes a robotic-transferring device
101
. Targets
104
A to
104
J for the separate sputtering deposition of the various magnetic layers from which the magnetic layer films are configured, are provided in a circular arrangement in the inner part of the film-deposition chamber
103
. A substrate carried in from a loading chamber
105
is introduced to the film-deposition chamber
103
by the robot carrying device
101
within the carrying chamber
102
, whereupon the formation of the magnetic film layer on the substrate is performed. The manufacture of the magnetic multi-layer film is performed by sputtering film deposition in which the substrate is caused to move, by way of example, in a clockwise direction, and is stopped, by the movement thereof, below each of the targets
104
A to
104
J. The magnetic multi-layer film is manufactured on the substrate using the single film-deposition chamber
103
, in accordance with targets arranged in an order established in advance, by the continuous successive film deposition of all of the magnetic film layers from a bottom layer in accordance with a set order. In this sputtering film deposition, normally, the targets are arranged horizontally, and the surface of the substrate is arranged in an opposing state with respect to the surface of said targets. When the continuous multi-layer film depositing of the magnetic multi-layer films—which use the plurality of targets
104
A to
104
J correspondent to the number of layers of multi-layer magnetic films in the film-depositing chamber
103
—is completed, the substrate in which the film-depositing process has been completed is carried along by the robot transferring device
101
of the transferring chamber
102
, and is carried out through an unloading chamber
106
.
In the above-described conventional continuous multi-layer film deposition of the magnetic multi-layer film, because of the configuration of the sputtering film depositing apparatus, deposition is performed, without interruption of the film deposition, from the bottommost layer until completion of the film deposition of the uppermost layer. On the other hand, the configuration for the production of multi-layer films from which semiconductor devices are made is generally one which comprises a transferring chamber at the center and a plurality of film-depositing chambers provided in the perimeter thereof and, as a cluster-type, is one in which each of the multi-layer films are deposited using a plurality of film-depositing chambers. Compared to the configuration of the multi-layer film manufacturing apparatus pertaining to ordinary semiconductor devices, the configuration of a representative multi-layer sputtering film depositing apparatus of the prior art may be described as unique.
In the development of a sputtering film depositing apparatus for magnetic heads that is suitable for the mass production of magnetic heads for the abovementioned TMR elements that comprise magnetic multi-layer films, the adoption of a configuration that is compatible with the general configuration of a semiconductor device manufacturing apparatus, and not a unique configuration, is demanded.
In addition, there will be increased demand in the future for, as a non-volatile semiconductor memory, an MRAM (Magnetoresistive Random Access Memory) that comprises a magnetic multi-layer structure similar to TMR elements in terms of improvement to memory integration degree and high-speed rewriting performance. In cases where, in response to this demand, the manufacture of magnetic multi-layer films has been performed by manufacturers which ordinarily produce semiconductor devices using the conventional configuration of the apparatus in which the multi-layer film deposition is performed continuously using one large film-depositing chamber, a sense of incompatibility has been felt in comparison to normal semiconductor device manufacturing methods. Thereupon, the semiconductor manufacturers, in consideration of the manufacture of MRAM using their own semiconductor production lines, have come to demand a magnetic multi-layer film manufacturing apparatus comprising a configuration (cluster system) suitable for semiconductor production lines.
In addition, in the continuous film deposition of conventional magnetic multi-layer films, because the film deposition must be continuous, without interruption, from the bottommost layer of the substrate to the uppermost layer, and a large number of magnetic films are deposited in one action, concerns exist regarding the restricting of improvements to the MR ratio.
Furthermore, in the production of MRAM, greater productivity is demanded compared to the production of magnetic heads. Based on the representative configuration of the magnetic multi-layer film manufacturing apparatus of the prior art described above, it is difficult to expect productivity improvements because of the continuous multi-layer film deposition.
An objective of the present invention, which is designed with the above-noted problems in mind, lies in the provision of a magnetic multi-layer film manufacturing apparatus which, in the production of MRAM and magnetic heads comprising TMR elements and so on, comprises a normal configuration which, notably, is a configuration suitable for the deposition of magnetic multi-layer films by manufacturers of semiconductor devices, and in which, furthermore, the film performance can be increased and productivity can be improved.
SUMMAR
Miyoshi Ayumu
Nomura Shuji
Tsunekawa Koji
Anelva Corporation
Burns Doane , Swecker, Mathis LLP
VerSteeg Steven H.
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