Patent Grant
8070969
This invention relates to the fabrication of devices incorporating microelectromechanical systems (MEMS). More particularly, the invention relates to a method of fabricating a MEMS device using at least one UV curable tape. For the sake of brevity, such a device shall be referred to below as a MEMS device and the part of the device comprising the microelectromechanical system shall be referred to as a MEMS layer.
Various methods, systems and apparatus relating to the present invention are disclosed in the following co-pending applications filed by the applicant or assignee of the present invention simultaneously with the present application:
The disclosures of these co-pending applications are incorporated herein by cross-reference.
According to an aspect of the present invention there is provided a method of fabricating microelectromechanical systems devices, the method comprising the steps of:
providing a silicon substrate having a plurality of microelectromechanical systems elements formed on a first surface thereof;
applying a guard layer defining a plurality of recesses to the silicon substrate such that respective microelectromechanical systems elements are located within respective recesses;
segmenting the silicon substrate into discrete parts;
bonding an adhesive layer to a second surface of the silicon substrate, the second surface being opposite said first surface and the adhesive layer being curable in the presence of light;
segmenting the guard layer into discrete parts corresponding to the discrete parts of the silicon substrate thereby forming individual microelectromechanical systems devices; and
selectively exposing the adhesive layer to a light source allowing removal of individual microelectromechanical systems devices.
Various other aspects of the present invention are also disclosed.
The invention is now described by way of example with reference to the accompanying diagrammatic drawings in which:—
In an initial step, illustrated at 10 in
The wafer 14 carries a surface macromachined MEMS layer 16 on the first surface 12 of the wafer 14. The MEMS layer 16 comprises individual MEMS elements 18.
The invention has particular application in the manufacture of ink jet printheads. For ease of explanation, the invention will be described with reference to that application. Thus, the layer 10 is a nozzle guard layer or wafer which is applied to the surface 12 of the silicon substrate 14. Each individual MEMS element 18 is in the form of a nozzle assembly. Each nozzle assembly 18 comprises an ink ejection nozzle and its associated actuator. The actuator acts on the nozzle for effecting ink ejection, on demand.
The purpose of the method of manufacture is to form individual MEMS chips 20 (
Hence, after the nozzle guard layer 10 has been applied to the wafer 14, the wafer 14 is turned over to expose a reverse side 22 as shown in
Various operations are then carried out on the wafer 14. In particular, the wafer 14 is back etched, from the surface 22 towards the surface 12 to separate the silicon wafer into discrete parts 24. In addition, in this application of the invention, ink inlet apertures 26 are etched through the parts 24. It is to be noted that each part 24 comprises a plurality of MEMS elements 18 and a bond pad 28. Also, as shown more clearly in
A holding means in the form of an adhesive tape 38 is bonded to the surface 22 of the layer 14 as illustrated in
Depending on the equipment used, a handling means in the form of a glass, quartz, alumina or other transparent handle wafer 40 is secured to an opposite surface of the tape 38.
The wafer 40, the tape 38, the silicon wafer 14 and the nozzle guard layer 10 define a laminate 42. The laminate 42 is then turned over, as shown in
Predetermined operations are carried out on the layer 10. More particularly, passages 44 are etched through the layer 10 from an outer surface 46 towards the chambers 36. In addition, individual nozzle guards 48 are formed by etching to remove material as shown at 50 in
In this embodiment of the invention, each chip 20 has a plurality of MEMS elements 18 in an array formed thereon.
The laminate 42 is placed on an xy wafer stage (not shown) which is reciprocated, as illustrated by arrow 52 in
Hence, it is an advantage of the invention, that a method of fabrication is provided which facilitates the performing of various operations to fabricate the individual MEMS chip 20 and which facilitates removal of the MEMS chips 20 for packaging. It will be appreciated that devices of the kind in question are measured in micron dimensions. Accordingly, the MEMS elements 18 on such devices are extremely fragile. The provision of the nozzle guard layer 10 and the use of the UV curable tape 38 facilitates that the MEMS elements 18 are not touched by solids or liquids after they are released by the release etch.
It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.
This Application a continuation application of U.S. application Ser. No. 11/450,431 filed on Jun. 12, 2006, now issued U.S. Pat. No. 746,5405, which is a continuation application of U.S. application Ser. No. 10/296,660 filed on Aug. 1, 2003, now U.S. Pat. No. 7,063,993, which is a national phase (371) application of PCT/AU00/00583, filed on May 24, 2000, all of which are herein incorporated by reference.
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| Number | Date | Country | |
|---|---|---|---|
| 20090061562 A1 | Mar 2009 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11450431 | Jun 2006 | US |
| Child | 12268966 | US | |
| Parent | 10296660 | US | |
| Child | 11450431 | US |
