US20080157413A1 - Method of manufacturing optical interference color display - Google Patents

Abstract

The method of manufacturing an optical interference color display is described. A first electrode structure is formed over a substrate first. At least one first area, second area and third area are defined on the first electrode structure. A first sacrificial layer is formed over the first electrode structure of the first area, the second area and the third area. Moreover, a second sacrificial layer is formed over the first sacrificial layer inside the second area and the third area. In addition, a third sacrificial layer is formed over the second sacrificial layer inside the third area. The etching rates of all sacrificial layers are different. Then, a patterned support layer is formed over the first electrode structure. Next, a second electrode layer is formed and the sacrificial layers are removed to form air gaps. Therefore, the air gaps are effectively controlled by using the material having different etching rates.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a divisional application of U.S. application Ser. No. 11/133,641, filed on May 20, 2005, which claims the priority benefit of Taiwan application serial no. 94103551, filed on Feb. 4, 2005. The disclosures of both applications are hereby incorporated by reference in their entireties.
BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• The present invention relates to a method of fabricating an optical interference color display, and more particularly to a method of fabricating an optical interference color display capable of controlling air gaps formed in the optical interference color display precisely.
• 2. Description of the Related Art
• Panel displays, such as liquid crystal (LCD) displays, organic electro-luminescence (OEL) displays, or plasma display panels (PDPs), which are light and slim, have been widely used in our daily life. Wherein, LCD displays have gradually dominated the market. However, LCD displays still have some disadvantages. For example, the angles are not wide enough, the response time is not fast, and requirement of using polarizer results in poor utilization of light source.
• An optical interference color display has been developed to date.FIG. 1 is a schematic drawing showing a conventional optical interference color display. The conventional opticalinterference color display100 comprises atransparent substrate110, afirst electrode structure120, apatterned support layer130 and asecond electrode layer140. Thefirst electrode structure120 comprises a plurality offirst electrodes122, anabsorption layer124 and anoptical layer126, from bottom to top. Note that a plurality of air gaps G1-G3 is formed (defined) between thefirst electrode structure120 and theoptical layer126.
• After propagating into thefirst electrode structure120 through thetransparent substrate110, light propagates to thefirst electrode structure120 through the air gaps G1-G3. Then, the light is reflected by thesecond electrode layer140 and propagates through thefirst electrode structure120. Due to different light interferences in the different air gaps G1-G3, different color lights, such as red, green and blue lights, are generated for displaying. The forming of the air gaps G1-G3, however, is determined by the thicknesses of the sacrificial layers. Detailed description will be mentioned later. In other words, the quality of the sacrificial layers will affect the optical performance of the opticalinterference color display100.
• FIGS. 2A-2D are cross sectional views showing progress of a method of forming sacrificial layers. Referring toFIG. 2A, atransparent substrate110 is provided. Afirst electrode structure120 is then formed over thetransparent substrate110. Thefirst electrode structure120 comprises a plurality offirst electrodes122, anabsorption layer124 and anoptical layer126, from bottom to top. In addition, afirst area10, asecond area20 and athird area30 are defined on thefirst electrode structure120.
• Referring toFIG. 2B, a firstsacrificial layer132, e.g., amorphous silicon, is entirely deposited. A photolithographic process and an etch process are performed to remove the firstsacrificial layer132 outside thefirst area10, thesecond area20 and thethird area30 to form a firstsacrificial layer132 with designated patterning.
• Referring toFIG. 2C, a secondsacrificial layer134 is entirely deposited. The secondsacrificial layer134 and the firstsacrificial layer132 are the same material. A photolithographic process and an etch process are performed to remove the secondsacrificial layer134 outside thesecond area20 and thethird area30 to form a secondsacrificial layer134 with designated patterning. Note that while removing the secondsacrificial layer134 of thefirst area10 by the etch process, the firstsacrificial layer132 and the secondsacrificial layer134 are the same material, i.e., the same etching rate. Accordingly, the firstsacrificial layer132 is easily damaged by the etchant used in the etch process such that the original thickness of thesacrificial layer132 is changed. That causes impact to the subsequent processes.
• Referring toFIG. 2D, a thirdsacrificial layer136 is entirely deposited. The thirdsacrificial layer136, the secondsacrificial layer134 and the firstsacrificial layer132 are the same material. A photolithographic process and an etch process are performed to remove the thirdsacrificial layer136 outside thethird area30 to form a thirdsacrificial layer136 with designated patterning. The process of forming the sacrificial layers is thus complete. Note that the thirdsacrificial layer136 is on the firstsacrificial layer132 while the thirdsacrificial layer136 of thefirst area10 is removed by the etch process, thus the firstsacrificial layer132 is damaged easily. Similarly, while removing the thirdsacrificial layer136 of thesecond area20, the thirdsacrificial layer136 is on the firstsacrificial layer132, and the firstsacrificial layer132 and the thirdsacrificial layer136 have the same etching rate. Accordingly, while the thirdsacrificial layer136 is removed, the secondsacrificial layer134 is also damaged easily.
• Finally, a photoresist layer is entirely coated. The photoresist layer is then patterned to form apatterned support layer130. Then, asecond electrode layer140 is formed over the sacrificial layers with different thicknesses of thefirst area10, thesecond area20 and thethird area30, and a portion of thepatterned support layer130. Thereafter, etchant, such as XeF₆, is then used to remove allsacrificial layers132,134 and136 to form different air gaps G1-G3 as shown inFIG. 1.
• In other words, the thicknesses of the deposited sacrificial layers determine the formation of the air gaps G1-G3. If the desired thicknesses of the sacrificial layers are changed due to the damaged sacrificial layers, the dimensions of the air gaps G1-G3 cannot be precisely controlled. The optical performance of the opticalinterference color display100 is seriously affected. Under the described unstable manufacturing processes, yields are declined and manufacturing costs are also increased.
SUMMARY OF THE INVENTION
• Accordingly, the present invention is directed to a method of fabricating an optical interference color display. In this method, the thicknesses of the sacrificial layers can be precisely controlled so that better air gaps can be obtained.
• The present invention is also directed to a method of fabricating an optical interference color display. In this method, better air gaps can be formed, and the optical performance of the optical interference color display can be enhanced.
• As embodied and broadly described herein, a method of fabricating an optical interference color display is provided. In this method, a substrate is first provided. A first electrode structure is formed over the substrate. A first area, a second area and a third area are then defined on the first electrode structure. A first sacrificial layer is formed over the first electrode structure inside the first area, the second area and the third area. A second sacrificial layer is then formed over the first sacrificial layer inside the second area and the third area. A third sacrificial layer is formed over the second sacrificial layer inside the third area. The first sacrificial layer, the second sacrificial layer and the third sacrificial have different etching rates. A patterned support layer is then formed over the first electrode structure. A second electrode layer is formed over the first sacrificial layer inside the first area, the second sacrificial layer inside the second area, the third sacrificial layer inside the third area, and a portion of the patterned support layer. Finally, the first sacrificial layer, the second sacrificial layer and the third sacrificial layer are removed to form a plurality of air gaps between the first electrode structure and the second electrode layer.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the substrate comprises, for example, a glass substrate or a plastic substrate.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the method of forming the first electrode structure comprises the following steps. A plurality of first electrodes is formed over the substrate. An absorption layer is then formed over the first electrodes. Finally, an optical layer is formed over the absorption layer.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the first electrodes are, for example, transparent electrodes, and the material of the first electrodes comprises, for example, indium tin oxide (ITO).
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the absorption layer comprises, for example, Chromium (Cr) or Molybdenum chromium (MoCr).
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the optical layer comprises, for example, silicon nitride or silicon oxide.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the patterned support layer comprises, for example, a photoresist layer.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the etching rate of the second sacrificial layer is more than 1.5 times of the etching rate of the first sacrificial layer, and the etching rate of the third sacrificial layer is more than 1.5 times of the etching rate of the second sacrificial layer.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the first sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the second sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the third sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the second electrode layer is a metal electrode. The material of the second electrode layer is selected from a group consisting of Mo, Mo alloy, aluminum, aluminum alloy, Cr, nickel, titanium, and a combination thereof, for example.
• As embodied and broadly described herein, the present invention provides a method of fabricating an optical interference color display. In this method, a substrate is provided first. A first electrode structure is formed over the substrate. A first area, a second area, and a third area are then defined on the first electrode structure. A first sacrificial layer is formed over the first electrode structure inside the first area. A second sacrificial layer is formed over the first electrode structure inside the second area. A third sacrificial layer is formed over the first electrode structure inside the third area. The first sacrificial layer, the second sacrificial layer and the third sacrificial have different etching rates and thicknesses. A patterned support layer is then formed over the first electrode structure. A second electrode layer is formed over the first sacrificial layer inside the first area, the second sacrificial layer inside the second area, the third sacrificial layer inside the third area, and a portion of the patterned support layer. Finally, the first sacrificial layer, the second sacrificial layer and the third sacrificial layer are removed to form a plurality of air gaps between the first electrode structure and the second electrode layer.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the substrate comprises, for example, a glass substrate or a plastic substrate.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the method of forming the first electrode structure comprises the following steps. A plurality of first electrodes is formed over the substrate. An absorption layer is then formed over the first electrodes. Finally, an optical layer is formed over the absorption layer.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the first electrodes are, for example, transparent electrodes, and the material of the first electrodes comprises, for example, indium tin oxide (ITO).
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the absorption layer comprises, for example, Chromium (Cr) or Molybdenum chromium (MoCr).
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the optical layer comprises, for example, silicon nitride or silicon oxide.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the patterned support layer comprises, for example, a photoresist layer.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the etching rate of the second sacrificial layer is more than 1.5 times of the etching rate of the first sacrificial layer, and the etching rate of the third sacrificial layer is more than 1.5 times of the etching rate of the second sacrificial layer.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the first sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the second sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the third sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example.
• According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the second electrode layer is a metal electrode. The material of the second electrode layer is selected from a group consisting of Mo, Mo alloy, aluminum, aluminum alloy, Cr, nickel, titanium, and a combination thereof, for example.
• As embodied and broadly described herein, the present invention provides a method of fabricating an optical interference color display. In this method, a substrate is first provided. A first electrode structure is formed over the substrate. A first area and a second area are then defined on the first electrode structure. A first sacrificial layer is formed over the first electrode structure inside the first area and the second area. A second sacrificial layer is then formed over the first sacrificial layer inside the second area. The first sacrificial layer and the second sacrificial layer have different etching rates. A patterned support layer is then formed over the first electrode structure. A second electrode layer is formed over the first sacrificial layer inside the first area, the second sacrificial layer inside the second area, and a portion of the patterned support layer. Finally, the first sacrificial layer and the second sacrificial layer are removed to form a plurality of air gaps between the first electrode structure and the second electrode layer.
• As embodied and broadly described herein, the present invention provides a method of fabricating an optical interference color display. In this method, a substrate is provided first. A first electrode structure is formed over the substrate. A first area and a second area are then defined on the first electrode structure. A first sacrificial layer is formed over the first electrode structure inside the first area. A second sacrificial layer is formed over the first electrode structure inside the second area. The first sacrificial layer and the second sacrificial layer have different etching rates and thicknesses. A patterned support layer is then formed over the first electrode structure. A second electrode layer is formed over the first sacrificial layer inside the first area, the second sacrificial layer inside the second area, and a portion of the patterned support layer. Finally, the first sacrificial layer and the second sacrificial layer are removed to form a plurality of air gaps between the first electrode structure and the second electrode layer.
• In the method of fabricating the optical interference color display, materials with different etching rates are used to form sacrificial layers. As a result, the sacrificial layers have different etching rates. While being etched, damage to the sacrificial layers can be prevented, and the better air gaps can be obtained. Accordingly, the optical performance of the optical interference color display can be improved.
• The above and other features of the present invention will be better understood from the following detailed description of the preferred embodiments of the invention that is provided in communication with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a schematic drawing showing a conventional optical interference color display.
• FIGS. 2A-2D are cross sectional views showing progress of a method of forming sacrificial layers.
• FIGS. 3A-3F are cross sectional views showing progress of a method of fabricating an optical interference color display according to the first embodiment of the present invention.
• FIGS. 4A-4F are cross sectional views showing progress of a method of fabricating an optical interference color display according to the second embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTFirst Embodiment
• FIGS. 3A-3F are cross sectional views showing progress of a method of fabricating an optical interference color display according to the first embodiment of the present invention. Referring toFIG. 3A, atransparent substrate210 is provided. Its material can be, for example, glass or plastic. Afirst electrode structure220 is then formed over thetransparent substrate210.
• The method of forming thefirst electrode structure220 can be, for example, a physical vapor deposition (PVD) process or other suitable processes, to deposit indium tin oxide (ITO) over thetransparent substrate210. The ITO layer is then patterned by a photolithographic process and an etching process to form a plurality of firsttransparent electrodes222. Anabsorption layer224 is then deposited over thefirst electrodes222 and partial area of thesubstrate210 where nofirst electrodes222 are formed. In one embodiment of the present invention, the material of theabsorption layer224 can be, for example, Chromium (Cr) or Molybdenum chromium (MoCr).
• Finally, anoptical layer226 is deposited over theabsorption layer224. Wherein, the material of theoptical layer226 can be, for example, silicon nitride or silicon oxide. Of course, theoptical layer226 is not limited to a single layer. It may comprise a plurality of dielectric layers with high refractive index and a plurality of dielectric layers with high refractive index stacked alternately. The steps described above form thefirst electrode structure220. Thefirst electrode structure220 comprises thefirst electrodes222, theabsorption layer224 and theoptical layer226. In addition, thefirst area10, thesecond area20 and thethird area30 are defined on thefirst electrode structure220.
• Referring toFIG. 3B, a firstsacrificial layer232 is entirely deposited. Its material can be selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example. Then, a photolithographic process and an etching process are performed to remove the firstsacrificial layer232 outside thefirst area10, thesecond area20 and thethird area30 to form the firstsacrificial layer232 with designated patterning.
• Referring toFIG. 3C, a secondsacrificial layer234 is entirely deposited. The secondsacrificial layer234 has an etching rate at least more than 1.5 times of that of the firstsacrificial layer232. The material of the secondsacrificial layer234 can be selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example. In some embodiments, as long as the etching rate of the secondsacrificial layer234 is higher than that of the firstsacrificial layer232, the material with etching rate higher than the etching rate of the firstsacrificial layer232 mentioned above can be used as the secondsacrificial layer234. For example, the first and the second sacrificial layers may be formed of the same material, such as amorphous silicon. They are then processed under different temperatures so that the firstsacrificial layer232 and the secondsacrificial layer234 have different etching rates. Nevertheless, as long as the materials have different etching rates to the same or different etchants, the materials can be used.
• A photolithographic process and an etching process are then performed to remove the secondsacrificial layer234 outside thesecond area20 and thethird area30 to form the patternedsacrificial layer234 with designated patterning. Note that the secondsacrificial layer234 is over the firstsacrificial layer232 while the secondsacrificial layer234 inside thefirst area10 is removed. The etch process can be, for example, a wet etch process or other suitable processes to remove the secondsacrificial layer234. Since the secondsacrificial layer234 has a higher etching rate, damage to the firstsacrificial layer232 can be reduced while the etch process is removing the secondsacrificial layer234. Accordingly, the thickness of the firstsacrificial layer232 can be maintained.
• Referring toFIG. 3D, a thirdsacrificial layer236 is then entirely deposited. A photolithographic process and an etch process are performed to remove the thirdsacrificial layer236 outside thethird area30 to form the thirdsacrificial layer236 with designated patterning. The fabrication of the sacrificial layers inside thefirst area10, thesecond area20 and thethird area30 are thus accomplished.
• Note that in order to pattern the thirdsacrificial layer236, a wet etch process or other suitable process is used to remove the thirdsacrificial layer236 inside thefirst area10 and the thirdsacrificial layer236 inside thesecond area20. The etching rate of the thirdsacrificial layer236 of thefirst area10 is higher than that of the firstsacrificial layer232. Though the firstsacrificial layer232 is under the secondsacrificial layer234, the firstsacrificial layer232 will not be damaged while the thirdsacrificial layer236 is removed.
• Similarly, the etching rate of the thirdsacrificial layer236 of thesecond area20 is more than 1.5 times of that of the secondsacrificial layer234, for example. Though the secondsacrificial layer234 is under the thirdsacrificial layer236, damage to the secondsacrificial layer234 can be reduced due to their different etching rates. In addition, the thicknesses of thesacrificial layers232,234,236 can be well controlled. It should be noted that the removing process of thesacrificial layers232,234,236 is so call releasing process.
• Referring toFIG. 3E, a photoresist layer is entirely coated. The photoresist layer is then patterned to form the patternedsupport layer230. Then, asecond electrode layer240 is entirely deposited. The material of thesecond electrode layer240 can be a light-reflective metal, such as Mo, Mo alloy, aluminum, aluminum alloy, Cr, nickel, titanium, or a combination thereof. A photolithographic process and an etch process are then performed to form the patternedsecond electrode layer240. Thesecond electrode layer240 is formed over the firstsacrificial layer232 inside thefirst area10, the secondsacrificial layer234 inside thesecond area20, the thirdsacrificial layer236 inside thethird area30 and a portion of the patternedsupport layer230.
• Referring toFIG. 3F, all of these sacrificial layers are removed by using suitable etchant, e.g. XeF₆to form different air gaps C1, C2 and C3. In detail, after forming thesecond electrode layer240 over the sacrificial layers with different thicknesses and performing releasing process, different air gaps C1, C2 and C3 can be formed simultaneously. In addition, the air gaps C1, C2 and C3 generally are smaller than, or equal to 1 μm. In this embodiment, the sacrificial layers have different etching rates. By depositing the sacrificial layer with a smaller etching rate first, damage to the earlier-deposited sacrificial layer can be reduced.
• Compared with the prior art technology, the present invention can well control the thicknesses of the sacrificial layers and improve the quality of the air gaps C1, C2, C3 and the manufacturing yields. The optical performance of the opticalinterference color display200 can also be enhanced.
Second Embodiment
• FIGS. 4A-4F are cross sectional views showing progress of a method of fabricating an optical interference color display according to the second embodiment of the present invention. Referring toFIG. 4A, the steps are similar to those shown inFIG. 3A. Afirst electrode structure220 is formed and thefirst area10, thesecond area20 and thethird area30 are defined.
• Referring toFIG. 4B, a firstsacrificial layer332 is entirely deposited. The material of the firstsacrificial layer332 can be selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example. Then, a photolithographic process and an etching process are performed to remove the firstsacrificial layer332 outside thefirst area10 to form the firstsacrificial layer332 with designate patterning.
• Referring toFIG. 4C, a secondsacrificial layer334 is entirely deposited. The material of the secondsacrificial layer334 has an etching rate at least more than 1.5 times of that of the firstsacrificial layer332, for example. The material of the secondsacrificial layer334 can be selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example. In some embodiments, as long as the etching rate of the secondsacrificial layer334 is higher than that of the firstsacrificial layer332, the material of the secondsacrificial layer334 can be used. For example, the first and the second sacrificial layers may be formed of the same material, such as amorphous silicon. They are then processed under different temperatures so that the firstsacrificial layer332 and the secondsacrificial layer334 have different etching rates. Nevertheless, whether the etchants are the same or different, as long as the sacrificial layers have different etching rates, the materials can be used.
• A photolithographic process and an etching process are then performed to the secondsacrificial layer334 to remove the secondsacrificial layer334 outside thesecond area20 to form the secondsacrificial layer334 with designate patterning. Note that the secondsacrificial layer334 is on top of the firstsacrificial layer332 while the secondsacrificial layer334 of thefirst area10 is removed. The etch process can be, for example, a wet etch process or other suitable processes to remove the secondsacrificial layer334. Since the secondsacrificial layer334 has a higher etching rate, damage to the firstsacrificial layer332 can be reduced while the secondsacrificial layer334 is removed by the etch process. Accordingly, the thickness of the firstsacrificial layer332 can be maintained.
• Referring toFIG. 4D, a thirdsacrificial layer336 is then entirely deposited. A photolithographic process and an etch process are performed to remove the thirdsacrificial layer336 outside thethird area30 to form the thirdsacrificial layer336 with designate patterning. The sacrificial layers inside thefirst area10, thesecond area20 and thethird area30 are thus accomplished.
• Note that in order to pattern the thirdsacrificial layer336, a wet etch process or other suitable process is used to remove the thirdsacrificial layer336 inside thefirst area10 and the thirdsacrificial layer336 inside thesecond area20. The etching rate of the thirdsacrificial layer336 inside thefirst area10 is higher than that of the firstsacrificial layer332. Though below the firstsacrificial layer332 is underneath, the firstsacrificial layer332 will not be damaged while the thirdsacrificial layer336 is removed.
• Similarly, the etching rate of the thirdsacrificial layer336 inside thesecond area20 is more than 1.5 times of that of the secondsacrificial layer334, for example. Though the secondsacrificial layer334 is below the thirdsacrificial layer336, damage to the secondsacrificial layer334 can be reduced due to their different etching rates. In addition, the thicknesses of the sacrificial layers can be well controlled.
• Referring toFIG. 4E, a photoresist layer is entirely coated. The photoresist layer is then patterned to form the patternedsupport layer330. Then, asecond electrode layer340 is entirely deposited. The material of thesecond electrode layer340 can be a light-reflective metal, such as Mo, Mo alloy, aluminum, aluminum alloy, Cr, nickel, titanium, or a combination thereof. A photolithographic process and an etch process are then performed to form thesecond electrode layer340 with designate patterning. Thesecond electrode layer340 is formed over the firstsacrificial layer332 inside thefirst area10, the secondsacrificial layer334 inside thesecond area20, the thirdsacrificial layer336 inside thethird area30 and a portion of the patternedsupport layer330.
• Referring toFIG. 4F, the steps of forming different air gaps C1, C2 and C3 as shown inFIG. 3F are illustrated. In detail, after forming thesecond electrode layer340 over the sacrificial layers with different thicknesses and performing releasing process, different air gaps D1, D2 and D3 can be defined. In this embodiment, by depositing the sacrificial layer with a smaller etching rate first, damage to the earlier-deposited sacrificial layer can be reduced.
• Embodiments described above are methods to form the air gaps C1-C3 and D1-D3. The present invention, however, is not limited thereto. In the method of fabricating the optical interference color display of the present invention, only two different air gaps may be formed. The fabrication method is similar to that described above. What is different is that mere the first and the second sacrificial layers are formed in other embodiment In addition, in the method of fabricating the optical interference color display of the present invention, more than three different air gaps can be formed. The fabrication method is similar to that described above. What is different is that in addition to the first, the second and the third sacrificial layers, additional sacrificial layers can be formed.
• Accordingly, the method of fabricating the optical interference color display comprises the following advantages:
• 1. In the method of fabricating the optical interference color display of the present invention, damage to the sacrificial layers can be avoided. The air gaps can be well controlled and the manufacturing yields can be improved. Accordingly, the optical performance of the optical interference color display is enhanced.
• 2. In the method of fabricating the optical interference color display of the present invention, materials with different etching rates are used to form the sacrificial layers. Damage to the sacrificial layers can be prevented and the thicknesses of the sacrificial layers can also be precisely controlled.
• Although the present invention has been described in terms of exemplary embodiments, it is not limited thereto. Rather, the appended claims should be constructed broadly to include other variants and embodiments of the invention which may be made by those skilled in the field of this art without departing from the scope and range of equivalents of the invention.

Claims (13)

1. A method of fabricating an optical interference color display, comprising:

providing a substrate, and forming a first electrode structure over the substrate;

defining a first area, a second area, and a third area on the first electrode structure;

forming a first sacrificial layer over the first electrode structure of the first area;

forming a second sacrificial layer over the first electrode structure of the second area;

forming a third sacrificial layer over the first electrode structure of the third area, wherein the first sacrificial layer, the second sacrificial layer and the third sacrificial layer having different etching rates and thicknesses;

forming a patterned support layer over the first electrode structure;

forming a second electrode layer over the first sacrificial layer inside the first area, the second sacrificial layer inside the second area, the third sacrificial layer inside the third area and a portion of the patterned support layer; and

removing the first sacrificial layer, the second sacrificial layer and the third sacrificial layer to form a plurality of air gaps between the first electrode structure and the second electrode layer.

2. The method of fabricating an optical interference color display ofclaim 1, wherein the substrate comprises a glass substrate or a plastic substrate.

3. The method of fabricating an optical interference color display ofclaim 1, wherein the steps of forming the first electrode structure comprise: forming a plurality of first electrodes over the substrate; forming an absorption layer over the first electrodes; and forming an optical layer over the absorption layer.

4. The method of fabricating an optical interference color display ofclaim 3, wherein the first electrodes are transparent electrodes, and a material of the first electrodes comprises indium tin oxide (ITO).

5. The method of fabricating an optical interference color display ofclaim 3, wherein a material of the absorption layer comprises Chromium (Cr) or Molybdenum chromium (MoCr).

6. The method of fabricating an optical interference color display ofclaim 3, wherein a material of the optical layer comprises silicon nitride or silicon oxide.

7. The method of fabricating an optical interference color display ofclaim 1, wherein a material of the patterned support layer comprises a photoresist layer.

8. The method of fabricating an optical interference color display ofclaim 1, wherein an etching rate of the second sacrificial layer is more than 1.5 times of an etching rate of the first sacrificial layer, and an etching rate of the third sacrificial layer is more than 1.5 times of the etching rate of the second sacrificial layer.

9. The method of fabricating an optical interference color display ofclaim 1, wherein a material of the first sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon.

10. The method of fabricating an optical interference color display ofclaim 1, wherein a material of the second sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon.

11. The method of fabricating an optical interference color display ofclaim 1, wherein a material of the third sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon.

12. The method of fabricating an optical interference color display ofclaim 1, wherein the second electrode layer is a metal electrode, and a material of the second electrode layer is selected from a group consisting of Mo, Mo alloy, aluminum, aluminum alloy, Cr, nickel, titanium, and a combination thereof.

13. A method of fabricating an optical interference color display, comprising:

providing a substrate, and forming a first electrode structure over the substrate;

defining a first area and a second area on the first electrode structure;

forming a first sacrificial layer over the first electrode structure of the first area;

forming a second sacrificial layer over the first electrode structure of the second area, the first sacrificial layer and the second sacrificial layer having different etching rates and thicknesses;

forming a patterned support layer over the first electrode structure;

forming a second electrode layer over the first sacrificial layer inside the first area, the second sacrificial layer inside the second area and a portion of the patterned support layer; and

removing the first sacrificial layer and the second sacrificial layer to form a plurality of air gaps between the first electrode structure and the second electrode layer.

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