OPTICAL AIR SLIT AND METHOD FOR MANUFACTURING OPTICAL AIR SLITS
A structure having an optical slit therein. The structure includes a substrate having an opening therethrough and a metal layer disposed on the substrate, such metal layer having a photolithographically formed slit therein, such slit being narrower than the opening and being disposed over the opening, portions of the metal layer disposed adjacent the slit being suspended over the opening and other portions of the metal layer being supported by the substrate.
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This disclosure relates generally to optical slits and more particularly to method for making relatively long, narrow optical air slits.
BACKGROUNDAs is known in the art, air slits have a wide range of use in optics. One such use is in hyper spectral imaging system where such systems are used to collect and process information from across the electromagnetic spectrum that can extend beyond the visible band.
As is also known, techniques used to form air optical slits include the use of laser cutting, photolithography, Electro Discharge Machining (EDM), thin film deposition, e-beam lithography, RF/DC & reactive sputtering, Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), Chemical wet etch, electroplating, electro etching, sputter etching and ion milling.
SUMMARYIn accordance with the disclosure, a structure is provided having an optical slit therein, comprising: a substrate having an opening there through; and a metal layer disposed on the substrate, such metal layer having a slit therein, such slit being narrower than the opening and being disposed over the opening, portions of the metal layer disposed adjacent the slit being suspended over the opening and other portions of the metal layer being supported by the substrate.
In one embodiment, a method is provided for forming a structure having an optical slit therein. The method includes: forming an opening through a portion of a substrate; filling the opening with a sacrificial material, such material extending through a portion of the opening with portion of the material being disposed onto adjacent portions of an upper surface of the substrate; polishing the sacrificial material to remove the portions of the sacrificial material disposed onto adjacent portions of the upper surface of the substrate; forming a metalized layer on the upper surface of the substrate and the polished sacrificial material; applying a photolithographically processable material on an upper surface of the metalized layer; photolithographically forming a slit in the photolithographically processable material to expose a portion of the upper surface of the metallized layer, such slit being disposed over the opening in the portion of the substrate; etching to remove the exposed portion of the upper surface of the metalized layer to expose the sacrificial material while retaining unexposed portions of the metallized layer; and removing the sacrificial layer and the photolithographically processable material.
In one embodiment, the unexposed portions of the metallized layer are electroplated to a predetermined thickness.
In one embodiment, the electroplating is performed prior to the forming of the slit.
In one embodiment, the electroplating is performed subsequent to forming of the slit.
In one embodiment, the opening is formed using laser cutting.
The details of one or more embodiments of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims.
Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTIONReferring now to
Next, an opening 12 (
Next, the opening 12 is filled with a sacrificial material 14, such material having portions 14a extending through the opening 12 with portion 14b of the material 12 being disposed onto adjacent portions of an upper surface 16 of the substrate 10, as shown in
Next, a metalized layer 18 is deposited, for example electroplated, on the upper surface of the substrate 12 and the polished sacrificial material 14, as shown in
Next, a conventional photolithographically processable material 20 is deposited on an upper surface of the metalized layer 18, as shown in
Next, a slit 24 is photolithographically formed in the photolithographically processable material 20 using any conventional photolithographic-etching technique to expose an underlying portion of the upper surface of the metallized layer 18, such slit being disposed over the filled opening 12 in
Next, the exposed underlying portion of the metalized layer 18 is removed by any conventional etching process to form there a slit 26 having a width in the range of 5 um to 60 um and a length in the range of 77 mm to 112 mm., as shown in
Next, the photoresist layer 20 is removed.
Next, the metalized layer 18, here acts as a seed layer and is electroplated with material 28; here material 25 is, for example, gold, copper, nickel, chromium or any standard electroplate-able metal used in the electroplating business, to form the resulting metalized layer 18 with a resulting predetermined thickness, here in the range of 0.5 mil to 1 mil; it being noted that the electroplating leaves a slit 26 in the material 28 so that slits 24, 26 are formed in the resulting metalized layer 18. It should be noted that the metalized layer 18 may be formed by electroplating the unexposed portions of the metallized layer to a predetermined thickness either prior to forming the slit 26 or subsequent to forming the slit 26.
Next, the sacrificial layer 14 is removed using for example, chemical solvents, epoxy stripper, oxygen plasma, and oxygen ion milling to form the structure shown in
A number of embodiments of the disclosure have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other embodiments are within the scope of the following claims.
Claims
1. A method for forming a structure having an optical slit therein, comprising;
- forming an opening through a portion of a substrate;
- filling the opening with a sacrificial material, such material extending through a portion of the opening with portion of the material being disposed onto adjacent portions of an upper surface of the substrate;
- polishing the sacrificial material to remove the portions of the sacrificial material disposed onto adjacent portions of the upper surface of the substrate;
- forming a metalized layer on the upper surface of the substrate and the polished sacrificial material;
- applying a photolithographically processable material on an upper surface of the metalized layer;
- photolithographically forming a slit in the photolithographically processable material to expose a portion of the upper surface of the metallized layer, such slit being disposed over the opening in the portion of the substrate;
- etching to remove the exposed portion of the upper surface of the metaled layer to expose the sacrificial material while retaining unexposed portions of the metallized layer;
- removing the sacrificial layer and the photolithographically processable material.
2. The method recited in claim 1 including electroplating the unexposed portions of the metallized layer to a predetermined thickness.
3. The method recited in claim 2 wherein the electroplating is performed prior to the forming of the slit.
4. The method recited in claim 2 wherein the electroplating is performed subsequent to forming of the slit.
5. The method recited in claim 1 wherein the opening is formed using laser cutting.
6. A structure having an optical slit therein, comprising:
- a substrate having an opening therethrough;
- a metal layer disposed on the substrate, such metal layer having a slit therein, such slit being narrower than the opening and being disposed over the opening, portions of the metal layer disposed adjacent the slit being suspended over the opening and other portions of the metal layer being supported by the substrate.
Type: Application
Filed: Oct 21, 2011
Publication Date: Apr 25, 2013
Applicant: Raytheon Company (Waltham, MA)
Inventor: Arturo L. Caigoy (Norco, CA)
Application Number: 13/278,254
International Classification: B32B 3/24 (20060101); G03F 7/20 (20060101); B32B 15/00 (20060101);