Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making electrical device
Reexamination Certificate
1999-04-13
2002-05-21
Huff, Mark F. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making electrical device
C430S314000, C430S316000, C430S317000, C430S318000
Reexamination Certificate
active
06391527
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of producing a micro structure using a micro mechanics, particularly to a method of producing a micro structure using electroplating, a method of producing a liquid discharge head, a liquid discharge head produced thereby, a head cartridge loaded with said liquid discharge head, and a device for discharging liquid produced therewith.
2. Related Background Art
In recent years, a micro machine having a small movable mechanism has been investigated by using micro mechanics techniques. Especially, a micro structure produced by using a semiconductor integrated circuit production technique (semiconductor photo lithography process) makes it possible to produce on a substrate a plurality of micro machine parts which are more miniaturized and highly reproductive. Accordingly, this provides relatively easier arraying and lower production costs, in addition, with such miniaturization, and more rapid responsibility can be expected as compared with conventional mechanical structures.
Of the micro mechanics techniques using a semiconductor photo lithography process, surface micro-machining which uses a sacrifice layer is a method in which micro structures such as a micro cantilever, a linear actuator or the like can be easily made on a substrate, and various devices have been developed using this process.
Two typical surface micro-machining methods which use a sacrifice layer will be described below.
A first surface micro-machining method is such that a poly silicon film or an SOI (Si on Insulator) film, formed into a thin layer through a silicon dioxide film on a silicon substrate, which is to become a micro structure is patterned in a desired shape and then the oxidizing film of silicon dioxide is removed with an aqueous solution of hydrofluoric acid. With this method, a linear actuator (D. Kobayashi et al., “An Integrated Lateral Tunneling Unit,” Proceedings of IEEE Micro Electro Mechanical Systems Workshop 1992, pp.214-219) or the like can be manufactured. In this method, a sacrifice layer for use in producing micro structures is a single layer common to all of the structures.
FIGS. 5A
to
5
E are diagrammatic illustrations of the production process of micro structures using this method. First, a silicon dioxide film
511
as a sacrifice layer, a poly silicon film
513
as a structure layer and a nickel mask layer
514
are formed on a substrate
512
in this order (FIG.
5
A). The nickel mask layer
514
is then patterned, and using this as a mask, the poly silicon film
513
is etched to produce micro structures A, B and C comprising the poly silicon film
513
(FIG.
5
B). After this, the nickel mask layer
514
is removed to allow the poly silicon film
513
to be exposed (FIG.
5
C), then the silicon dioxide film
511
is etched with an aqueous solution of hydrofluoric acid. This produces a void below the central micro structure B, as shown in FIG.
5
D. And in the micro structures A and C on both sides of the micro structure B, the silicon dioxide film
511
which supports both A and C is side-etched to have a cantilever shape. Lastly, a metal film
515
which is a laminate of Cr and Au in this order is deposited on the surface of each of the structures A, B and C so as to produce electrically conductive micro structures A, B and C (FIG.
5
E).
A second surface micro-machining method is such that micro structures are produced on the sacrifice layer, which has been formed into a desired pattern, by the thin-film formation process. With this method, a wharve micro motor (M. Mehregany et al., “Operation of microfabricated harmonic and ordinary side-drive motors,” Proceedings IEEE Micro Electro Mechanical Systems Workshop 1990, pp.1 to 8), a cantilever (L. C. Kong et al., Integrated electrostatically resonant scan tip for an atomic force microscope” J. Vac. Sci. Technol. Bll(3), p.634, 1993) or the like can be produced.
FIGS. 6A
to
6
D illustrate the production process of a cantilever using this method. First, a sacrifice film layer
611
is formed on a silicon substrate
612
having a passivation layer
614
formed on it, after which the sacrifice layer
611
is patterned by using semiconductor photo lithography techniques and etching (FIG.
6
A). A structure layer
613
, which is to become micro structures, is then formed on the substrate
612
(FIG.
6
B), and the structure layer
613
is patterned to have a desired shape using semiconductor photo lithography techniques and etching (FIG.
6
C). Then the sacrifice layer
611
is etched with an etchant capable of removing the sacrifice layer
611
alone so as to produce a cantilever
612
shown in FIG.
6
D. With this method, more complicated structures can be produced by forming a plurality of sacrifice layers and structure layers. (L. Y. Lin et al., “Micromachined Integrated Optics for Free-Space Interconnections,” Proceedings of IEEE Micro Electro Mechanical Systems Workshop 1995, pp.77 to 82).
SUMMARY OF THE INVENTION
The conventional methods of producing a micro structure mentioned above, however, have problems as follows.
First, in the first method shown in
FIGS. 5A
to
5
E, the length of the micro structures A and C on both sides depends on the etching conditions of the silicon dioxide film
511
, therefore the varying concentration, temperature and agitation of etching reagent may cause its variation. The variation of the length of a micro structure results in variation of mechanical properties, such as spring constant, resonance frequency, etc., of the cantilever and joist or the like which are connected to the structure. Thus, this method leads to a reduction in reproductivity of micro structures.
On the other hand, when the displacement of a cantilever is caused by external force, the stress typically concentrates on the base of the cantilever. In case of the cantilever
621
produced in the manner shown in
FIGS. 6A
to
6
D, the stress concentrates on an inflection portion
622
. The substrate bottom side of such an inflection portion becomes a concentration part of the stress D which is excessively strained, therefore deterioration in its mechanical strength with time tends to occur at that portion, which allows its breaking due to mechanical metal fatigue to easily occur.
The present invention has been made in light of such difficulties the foregoing prior arts have, and therefore, the object of the present invention is to provide a method of producing a micro structure of which
(1) variation in mechanical properties is small, and
(2) deterioration in its mechanical strength with time due to the stress concentration at the inflection portion can be controlled.
In order to attain the above object, one aspect of the present invention provides a method of producing a micro structure on a substrate which has a support portion and a plate-like portion supported thereby at a distance from the substrate, comprising the steps of:
forming a spacer layer consisting of an insulating material on a substrate having an electrically conductive layer formed on its surface,
forming a latent image layer consisting of an electrically conductive material on the spacer layer at a site where the plate-like portion of a structure is to be formed,
producing an aperture, where a part of the electrically conductive layer is exposed, on the spacer layer at a site where the supporting portion of a structure is to be formed,
forming a structure layer consisting of plating film inside of the aperture and on the latent image layer by electroplating the electrically conductive layer as a cathode, and
removing the spacer layer.
Another aspect of the present invention provides a method of producing a liquid discharge head for discharging liquid from a discharge port, wherein the liquid discharge head has at least a discharge port for discharging liquid, a liquid flow path in communication with the discharge port for supplying the liquid to the discharge port, a substrate provided with a heating element for allowing the liquid filled in the liquid flow
Hiroki Tomoyuki
Kubota Masahiko
Ozaki Teruo
Yagi Takayuki
Barreca Nicole
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Huff Mark F.
LandOfFree
Method of producing micro structure, method of production... 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 of producing micro structure, method of production..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of producing micro structure, method of production... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2884445