TWI502176B - Tunable filter element and menufacturing method thereof - Google Patents

Description

Adjustable filter element and manufacturing method thereof

The present disclosure relates to a filter element and a method of fabricating the same, and more particularly to an adjustable filter element and a method of fabricating the same.

At present, there are many kinds of biochip detecting devices, and optical detecting devices are more mainstream. Specifically, biochips are designed using the principles of molecular biology, genetic information, and analytical chemistry to produce wafers, glass, or polymers, and micro-electromechanical automation or other precision processing technologies. Components, such as semiconductor wafers, can generally perform complex calculations quickly, so biochips have fast, accurate, and low-cost bioanalytical inspection capabilities. Currently developing biochips can be roughly divided into two categories: gene chip and lab-on-a-chip.

On the other hand, a common optical detecting device is, for example, a spectrometer, which is a kind of physical and chemical analysis instrument, which can be distinguished into different kinds of spectrometers according to applicable wavelengths, such as an ultraviolet-visible spectrometer, a near-infrared spectrometer, and an infrared spectrum. instrument. Specifically, UV-Vis spectrometers are commonly used for color measurement, water quality analysis, and biochemical tests. Near-infrared spectrometers can be used for process monitoring in food processing and pharmaceutical industries, while infrared spectrometers are commonly used for gas analysis.

The main function of the spectrometer is to scientifically decompose the complex light into a spectral line. It consists of a 稜鏡 or a diffraction grating. When the complex light is split by a spectroscopic element (such as a grating or a prism), it depends on the wavelength of the light. The size of (or frequency) is sequentially arranged to form a pattern. In other words, the spectrometer does not achieve the simultaneous filtering of light in more than two bands to achieve the specific detection parameters. In addition, spectrometers generally have the disadvantages of excessive volume, difficulty in reduction, and high cost. Therefore, how to miniaturize the photodetection device and reduce the cost is one of the problems to be solved in the technical field.

An embodiment of the present disclosure provides an adjustable filter element including a substrate layer, a support assembly, a first filter structure, a second filter structure, a first elastic unit, a second elastic unit, a first upper electrode, and Second upper electrode. The substrate layer includes a substrate, a first reflective film, a second reflective film, a first lower electrode, and a second lower electrode. The first reflective film and the second reflective film are disposed on the substrate. The first lower electrode and the second lower electrode are disposed on the substrate, wherein the first lower electrode is disposed beside the first reflective film, and the second lower electrode is disposed beside the second reflective film. The support assembly is disposed on the substrate. The first filter structure is located above the first reflective film. The second filter structure is located above the second reflective film. The first elastic unit connects the first filter structure and the support assembly. Second bomb The sex unit connects the second filter structure and the support assembly. The first upper electrode is connected to the first filter structure. The second upper electrode is connected to the second filter structure.

An embodiment of the present disclosure provides a method for fabricating a tunable filter element, including: forming a reflective film substrate layer; providing a wafer substrate, wherein the wafer substrate includes a ruthenium substrate, an insulating layer, and a substrate layer; Forming a nitride layer thereon; etching a nitride layer to expose a portion of the surface of the germanium substrate; forming at least one support mount and a barrier layer on the germanium substrate, wherein the barrier layer is located between the support mounts; Forming a first filter structure, a second filter structure, a first upper electrode, a second upper electrode, and a second metal line, wherein the first upper electrode is connected to the first filter structure, and the second upper electrode is connected to the first a second filter structure; the bonding germanium substrate and the substrate layer, wherein the first filter structure faces the first reflective film, the second filter structure faces the second reflective film; and the first elastic unit and the second elastic unit are respectively formed On the substrate, the first elastic unit is connected to the first filter structure and the partial support mount, and the second elastic unit is connected to the second filter structure and the other part support mount.

The above described features and advantages of the present invention will be more apparent from the following description.

10‧‧‧Light source device

12‧‧‧ Beam

12a‧‧‧First light

12b‧‧‧second light

30, 40‧‧‧Light detection unit

50‧‧‧Test object

56‧‧‧ frame

60‧‧‧Detection device

100‧‧‧Adjustable filter elements

110‧‧‧ substrate layer

111‧‧‧Substrate

112‧‧‧First reflective film

113‧‧‧Second reflective film

114‧‧‧First lower electrode

115‧‧‧second lower electrode

116‧‧‧First metal line

117‧‧‧ protective oxide layer

118‧‧‧Intermediate window

120‧‧‧Support components

120a‧‧‧Support mount

130‧‧‧First filter structure

130a‧‧‧First filter layer

130b‧‧‧third reflective film

140‧‧‧Second filter structure

140a‧‧‧Second filter layer

140b‧‧‧fourth reflective film

150‧‧‧First elastic unit

152‧‧‧Main elastic member

154, 156‧‧‧ sub-elastic members

160‧‧‧Second elastic unit

170‧‧‧First upper electrode

180‧‧‧Second upper electrode

190a‧‧‧First frame structure

190a1, 190b1‧‧‧ bottom

190b‧‧‧second frame structure

210‧‧‧ wafer substrate

211‧‧‧矽 substrate

211a‧‧‧ surface

211b‧‧‧ nitride layer

211c‧‧‧Block

212‧‧‧ substrate layer

213, 214‧‧‧ oxide layer

215‧‧‧Second metal line

A1‧‧‧first axial direction

A2‧‧‧second axial

F‧‧‧Electrostatic attraction

G‧‧‧Initial spacing

G1‧‧‧ first spacing

G2‧‧‧Second spacing

L‧‧‧Transfer path

FIG. 1 is a schematic diagram of a detecting apparatus according to an embodiment of the present disclosure.

2 is a top plan view of the adjustable filter element of FIG. 1.

3 is a cross-sectional view of the adjustable filter element of FIG. 2 taken along line A-A.

4 is a schematic cross-sectional view of the adjustable filter element of FIG. 2 after being electrostatically attracted.

5A to 5M are flowcharts showing the fabrication of the adjustable filter element of Fig. 2.

FIG. 1 is a schematic diagram of a detecting apparatus according to an embodiment of the present disclosure. 2 is a top plan view of the adjustable filter element of FIG. 1. 3 is a cross-sectional view of the adjustable filter element of FIG. 2 taken along line A-A. Referring to FIG. 1 , in the embodiment, the detecting device 60 is configured to detect the light beam 12 emitted by the light source device 10 . The detecting device 60 includes an adjustable filter element 100 and light detecting units 30 and 40. The adjustable filter element 100 is, for example, a synchronous multi-channel adjustable filter element for synchronously filtering out at least two different bands. Light waves.

In detail, the adjustable filter element 100 and the light detecting unit 30, 40 are located on the transmission path L of the light beam 12, wherein after the light beam 12 passes through the adjustable filter element 100, the first light 12a of two different wavelength bands is generated. And the second light 12b, and the first light 12a and the second light 12b are respectively transmitted to the light detecting units 30, 40. In the present embodiment, the light source device 10 is, for example, a light emitting diode (LED) for emitting a light beam 12 having a full wavelength band. The light beam 12 passes along its transmission path L through a side object 50 between the light source device 10 and the adjustable filter element 100, wherein the object to be tested 50 is, for example, a biochip such as a microfluidic wafer or a protein wafer, or other carrier.

Since the tissue in the analyte contains a large amount of water molecules, the water molecules absorb some of the light in the band (usually the infrared (IR) band between 1300 nm and 2600 nm). Second, the melanin in the tissue also absorbs ultraviolet light. (ultraviolet) light waves in the band and visible light. In other words, in order to obtain the amount of change of the light of the specific wavelength band, after the light beam 12 passes through the tunable filter element 100, the generated first light 12a and second light 12b are, for example, ultraviolet (UV) band and visible light band. The combination of light waves, or a combination of either the infrared (IR) band, the ultraviolet (UV) band, and the visible wave, may be adjusted for visual detection, and the disclosure is not limited herein. .

Referring to FIG. 2 and FIG. 3 , in the embodiment, the adjustable filter element 100 includes a substrate layer 110 , a support assembly 120 , a first filter structure 130 , a second filter structure 140 , and a first elastic unit 150 . The second elastic unit 160, the first upper electrode 170, and the second upper electrode 180. The substrate layer 110 includes a substrate 111, a first reflective film 112, a second reflective film 113, a first lower electrode 114, and a second lower electrode 115. The base material layer 110 is a transparent base material layer, and is made of, for example, a glass wafer.

The first reflective film 112 and the second reflective film 113 are disposed on the substrate 111. The first lower electrode 114 and the second lower electrode 115 are disposed on the substrate 111. The first lower electrode 114 is disposed adjacent to the first reflective film 112, and the second lower electrode 115 is disposed adjacent to the second reflective film 113. In detail, the first reflective film 112 and the second reflective film 113 are, for example, dielectric materials or semiconductor materials having different refractive indices by a thin film deposition technique (physical vapor deposition or chemical vapor deposition). The high-low continuous refractive index is periodically alternately stacked to form a distributed Bragg Reflector (DBR) of the multilayer film stack.

In this embodiment, the support assembly 120 is disposed on the substrate 111. the first The filter structure 130 is located above the first reflective film 112. The second filter structure 140 is located above the second reflective film 113. The first elastic unit 150 connects the first filter structure 130 and the support assembly 120. The second elastic unit 160 connects the second filter structure 140 and the support assembly 120 , wherein the elastic coefficient of the first elastic unit 150 is different from the elastic coefficient of the second elastic unit 160 . The first upper electrode 170 is connected to the first filter structure 130. The second upper electrode 180 is connected to the second filter structure 140.

Specifically, the support assembly 120 is composed of, for example, a plurality of support fixing seats 120a. The first elastic unit 150 and the second elastic unit 160 are connected to the substrate 111 through the support fixing seats 120a, and the first filter structure 130 and the first filter structure 130 A reflective film 112 has the same initial pitch G between the second filter structure 140 and the second reflective film 113.

In this embodiment, the adjustable filter element 100 further includes a first frame structure 190a and a second frame structure 190b. In detail, the first filter structure 130 is coupled to the first frame structure 190a, wherein the first frame structure 190a is coupled to the first elastic unit 150 along the first axial direction A1, and the first upper electrode 170 is disposed at the first filter Next to the light structure 130. That is, the first upper electrode 170 of the present embodiment is, for example, located on the bottom surface 190a1 of the first frame structure 190a facing the first lower electrode 114.

On the other hand, the second filter structure 140 is coupled to the second frame structure 190b, wherein the second frame structure 190b is coupled to the second elastic unit 160 along the first axial direction A1 and the second axial direction A2 of the vertical first axial direction A1. And the second upper electrode 180 is disposed at the side of the second filter structure 140. That is, the second upper electrode 180 of the present embodiment is, for example, located on the bottom surface of the second frame structure 190b facing the second lower electrode 115. On 190b1.

In the embodiment, the first filter structure 130 includes a first filter layer 130a and a third reflective film 130b, and the third reflective film 130b is located between the first filter layer 130a and the substrate 111. In addition, the second filter structure 140 includes a second filter layer 140a and a fourth reflective film 140b, and the fourth reflective film 140b is located between the second filter layer 140a and the substrate 111. In general, the first filter layer 130a and the second filter layer 140a are bandpass filters for filtering infrared (IR), ultraviolet (UV) or visible light bands. The stray light.

It is to be noted that the third reflective film 130b and the fourth reflective film 140b are also, for example, dielectric materials or semiconductors having different refractive indices by thin film deposition techniques (physical vapor deposition or chemical vapor deposition). The material is periodically alternately stacked with high and low refractive indices to form a distributed Bragg Reflector (DBR) of the multilayer film stack.

In the present embodiment, the first elastic unit 150 includes a main elastic member 152 and two sub-elastic members 154, 156, wherein the sub-elastic members 154, 156 are coupled to the main elastic member 152 by the first frame structure 190a. In detail, the main elastic member 152 and the second elastic unit 160 of the first elastic unit 150 constitute a frame 56 , and the frame 56 surrounds the first filter structure 130 and the second filter structure 140 . On the other hand, the sub-elastic members 154, 156 are, for example, symmetrically connected to opposite sides of the first frame structure 190a, and extend toward the frame 56 along the second axial direction A2 such that the sub-elastic members 154, 156 are respectively connected to the first A frame structure 190a is interposed between the support base 120a. That is, the first elastic unit 150 is, for example, the main elastic member 152 and the sub elastic members 154, 156. Spring structure in series.

Specifically, the main elastic member 152 of the first elastic unit 150 has the same elastic modulus as the second elastic unit 160, but since the first elastic unit 150 is formed by connecting the main elastic member 152 and the sub elastic members 154 and 156 in series, Therefore, it can be known that the elastic modulus of the first elastic unit 150 is smaller than the elastic modulus of the second elastic unit 160, and the disclosure is not limited thereto.

4 is a cross-sectional view of the adjustable filter element of FIG. 2 after being electrostatically attracted. Referring to FIG. 2 and FIG. 4, when the same voltage is applied between the first upper electrode 170 and the first lower electrode 114 and between the second upper electrode 180 and the second lower electrode 115, the first upper electrode 170 and the first An electrostatic attraction force F is generated between the lower electrodes 114 and between the second upper electrode 180 and the second lower electrode 115, so that the first filter structure 130 and the second filter structure 140 move toward the substrate 111, and the first filter is made The structure 130 has a first pitch G1 between the first reflective film 112 and a second pitch G2 between the second filter structure 140 and the second reflective film 113.

Furthermore, since the elastic modulus of the first elastic unit 150 is smaller than the elastic coefficient of the second elastic unit 160, and under the traction of the same electrostatic attractive force F, the displacement of the first frame structure 190a toward the substrate 111 will be caused. The amount is greater than the amount of displacement of the second frame structure 190b toward the substrate 111. That is, the first pitch G1 between the first filter structure 130 and the first reflective film 112 is smaller than the second pitch G2 between the second filter structure 140 and the second reflective film 113.

Thereby, as shown in FIG. 1, after the light beam 12 is incident on the adjustable filter element 100, the light beam 12 will be respectively between the first filter structure 130 and the first reflective film 112. Forming a Fabry-Perot interference between the second filter structure 140 and the second reflective film 113, so that a specific optical band can be filtered out, wherein the transmission spectrum is a function of the wavelength, and a peak of the transmission spectrum and a resonant cavity formed between the first filter structure 130 and the first reflective film 112 and between the second filter structure 140 and the second reflective film 113 Resonance corresponds. That is, the present disclosure adjusts the spacing between the first filter structure 130 and the first reflective film 112 and between the second filter structure 140 and the second reflective film 113 (and respectively is the first of two different sizes) The pitch G1 and the second pitch G2) are such as to achieve the interference phenomenon described above, and filter out the first light 12a of, for example, an infrared light (IR) band, an ultraviolet (UV) band, and a visible wave band, respectively. The second light 12b, wherein the first light 12a and the second light 12b are further transmitted to the light detecting units 30, 40, respectively, for the biological object such as a microfluidic chip or a protein wafer, or other The vector was analyzed.

On the other hand, although in the present embodiment, the elastic coefficient of the first elastic unit 150 and the second elastic unit 160 are different, the first filter structure 130 is made in the case of traction with the same electrostatic attraction. There are two different first pitches G1 and second pitches G2 between the first reflective film 112 and the second filter structure 140 and the second reflective film 113, but the disclosure is not limited thereto. Specifically, in other possible embodiments, the elastic coefficient of the first elastic unit of the present disclosure may be the same as that of the second elastic unit, by changing the size of the upper and lower electrodes, or applying different voltages to the first When the electrode is between the first lower electrode and the second upper electrode and the second lower electrode, to generate different electrostatic attractive forces, thereby obtaining The same technical effects as the above embodiment are obtained.

5A to 5M are flowcharts showing the fabrication of the adjustable filter element of Fig. 2. In terms of process, please refer to FIG. 5A first to provide a substrate 111 such as a glass wafer. Next, a first lower electrode 114, a second lower electrode 115, and an interconnected first metal line 116 are formed on the substrate 111 by metal deposition, for example, by chemical vapor deposition (CVD), that is, as shown in FIG. 5B. Shown. After the above process is completed, a protective oxide 117 is deposited on the substrate 111, and a plurality of vias 118 are formed on the protective oxide 117 to expose a portion of the surface of the substrate 111. A protective oxide 117 covers the first lower electrode 114, the second lower electrode 115, and the first metal line 116, as shown in FIG. 5C.

Thereafter, the first reflective film 112 and the second reflective film 113 are deposited on the substrate 111, wherein the first reflective film 112 and the second reflective film 113 are respectively located in the via window 118, and a part of the protective oxide layer is removed. 117 to expose a portion of the first metal line 116 for use in a subsequent bonding process, wherein the structural configuration of the foregoing process is known from FIG. 5D. So far, the fabrication of the substrate layer 110 has been completed.

Next, referring to FIG. 5E, a wafer substrate 210, and particularly an insulating layer overlay (SOI) wafer substrate, including a device layer 211, an insulating layer (not shown), and a handle layer is provided. 212, and nitride deposition is performed on the surface 211a of the ruthenium substrate 211 to form a nitride layer 211b. After the above process is completed, nitride etching is performed on the nitride layer 211b. A nitride etch is performed to expose a partial region of the surface 211a of the ruthenium substrate 211 as shown in FIG. 5F.

Next, referring to FIG. 5G, a silicon etch is performed on the germanium substrate 211 to form at least one support mount 120a. Thereafter, the nitride layer 211b is removed, and an oxide layer 213 is formed on a portion of the germanium substrate 211, and then the germanium substrate 211 is etched to form a stopper layer 211c as shown in FIG. 5H. With this configuration, stiction between structures and accuracy in subsequent processes can be prevented, with the barrier layer 211c being located between the support mounts 120a.

After the above process is completed, an oxide layer 214 (shown in FIG. 5I) is first deposited on the germanium substrate 211 as a barrier structure in a subsequent process, and then the first filter structure 130 and the second filter structure 140 are respectively formed. a first upper electrode 170, a second upper electrode 180, and a second metal line 215, wherein the first upper electrode 170 is connected to the first filter structure 130, the second upper electrode 180 is connected to the second filter structure 140, and the second The metal line 215 is formed after the oxide layer 213 on the support holder 120a is removed, as shown in FIG. 5I.

Specifically, the first filter structure 130 and the second filter structure 140 are formed by first forming a first filter layer 130a and a second filter layer 140a on the germanium substrate 211, wherein the first upper electrode 170 is connected. To the first filter layer 130a, the second upper electrode 180 is connected to the second filter layer 140a. Then, the third reflective film 130b and the fourth reflective film 140b are respectively deposited on the first filter layer 130a and the second filter layer 140a by metal deposition, for example, by chemical vapor deposition (CVD), to form separately. The first filter structure 130 and the second filter structure 140 are as shown in FIG. 5J.

Next, referring to FIG. 5K, the ruthenium substrate 211 and the substrate layer 110 as shown in FIG. 5D are connected by anodic bonding, and the first metal line 116 and the second metal line 215 are combined with each other. The first filter structure 130 formed by the filter layer 130a and the third reflective film 130b faces the first reflective film 112, and the second filter structure 140 composed of the second filter layer 140a and the fourth reflective film 140b Then, it faces the second reflective film 113. After the above process is completed, the insulating layer (not shown) on the wafer substrate 210 and the substrate layer 212 are removed.

Finally, referring to FIG. 5M, the germanium substrate 211 is etched to form a first elastic unit 150 and a second elastic unit 160, respectively, wherein the etching is performed by, for example, Deep Reactive Ion Etching (RIE). On the other hand, the first elastic unit 150 connects the first filter structure 130 and the partial support mount 120a, and the second elastic unit 160 connects the second filter structure 140 with the other partial support mounts 120a.

Specifically, the method of forming the first elastic unit 150 and the second elastic unit 160 on the 矽 substrate 211 includes forming a first frame structure 190a and a second frame structure 190b on the 矽 substrate 211, respectively, and the first filter structure 130 Connected to the first frame structure 190a, wherein the first frame structure 190a is coupled to the first elastic unit 150 along the first axial direction A1, and the first upper electrode 170 is disposed adjacent to the first filter structure 130. The second filter structure 140 is coupled to the second frame structure 190b, wherein the second frame structure 190b is coupled to the second elastic unit 160 along the first axis A1 and the second axis A2 of the vertical first axis A1, respectively, and The second upper electrode 180 is disposed beside the second filter structure 140, as shown in FIG. So far, the production of the adjustable filter element 100 has been carry out.

In summary, the adjustable filter element of the present disclosure is configured by respectively connecting two filter structures to two elastic units of different elastic coefficients, wherein each elastic unit is located above the substrate, corresponding to the two reflective film configurations of the respective filter structures. On the substrate. When the same voltage is applied between the corresponding upper and lower electrodes, an electrostatic attraction force is generated between the corresponding upper and lower electrodes, so that the respective filter structures move toward the substrate. Since the elastic coefficients of the respective elastic units are different from each other, the electrostatic attraction force causes two different spacings between the respective filter structures and the respective reflective films, and it is disclosed that the two elastic units can also apply different voltages with the same elastic coefficient. It is also possible to generate different distances at the same time. Thereby, light of different wavelength bands can be generated when the light beam passes through the adjustable filter element. That is to say, the present disclosure proposes an integrated adjustable filter element, which not only achieves the effect of simultaneously filtering out light of different wavelength bands, but also achieves the purpose of miniaturization and effectively reduces the cost of production.

The present disclosure has been disclosed in the above embodiments, but it is not intended to limit the disclosure, and any person skilled in the art can make some changes and refinements without departing from the spirit and scope of the disclosure. The scope of protection of this disclosure is subject to the definition of the scope of the appended claims.

100‧‧‧Adjustable filter elements

110‧‧‧ substrate layer

111‧‧‧Substrate

112‧‧‧First reflective film

113‧‧‧Second reflective film

114‧‧‧First lower electrode

115‧‧‧second lower electrode

116‧‧‧First metal line

117‧‧‧ protective oxide layer

120a‧‧‧Support mount

130‧‧‧First filter structure

130a‧‧‧First filter layer

130b‧‧‧third reflective film

140‧‧‧Second filter structure

140a‧‧‧Second filter layer

140b‧‧‧fourth reflective film

150‧‧‧First elastic unit

160‧‧‧Second elastic unit

170‧‧‧First upper electrode

180‧‧‧Second upper electrode

190a‧‧‧First frame structure

190a1, 190b1‧‧‧ bottom

190b‧‧‧second frame structure

211‧‧‧矽 substrate

211c‧‧‧Block

213, 214‧‧‧ oxide layer

215‧‧‧Second metal line

F‧‧‧Electrostatic attraction

G1‧‧‧ first spacing

G2‧‧‧Second spacing

Claims (11)

An adjustable filter element includes: a substrate layer comprising: a substrate; a first reflective film and a second reflective film disposed on the substrate; and a first lower electrode and a second lower electrode, Disposed on the substrate, wherein the first lower electrode is disposed beside the first reflective film, the second lower electrode is disposed beside the second reflective film; a support component is disposed on the substrate; a first filter a structure, located above the first reflective film; a second filter structure, located above the second reflective film; a first elastic unit connecting the first filter structure and the support assembly; a second elastic unit, connected The second filter structure and the support assembly; a first upper electrode connected to the first filter structure; and a second upper electrode connected to the second filter structure, the adjustable filter element satisfying a a first condition or a second condition, in which the modulus of elasticity of the first elastic unit is different from the modulus of elasticity of the second elastic unit, and when applying the same voltage to the first upper electrode and the first Next electrode And between the second upper electrode and the second lower electrode, the first filter structure and the first reflective film have a first spacing, and the second filter structure and the second reflective film Having a second spacing therebetween; In the second condition, the first elastic unit has the same spring rate as the second elastic unit, and when a different voltage is applied between the first upper electrode and the first lower electrode and the second Between the upper electrode and the second lower electrode, the first filter structure and the first reflective film have the first spacing, and the second filter structure and the second reflective film have the first Two spacing. The tunable filter element of claim 1, wherein the same voltage is applied between the first upper electrode and the first lower electrode and between the second upper electrode and the second lower electrode An electrostatic attraction force is generated between the first upper electrode and the first lower electrode and between the second upper electrode and the second lower electrode, such that the first filter structure and the second filter structure face the The substrate moves. The tunable filter element of claim 1, wherein the different voltage is applied between the first upper electrode and the first lower electrode and between the second upper electrode and the second lower electrode a different electrostatic attraction between the first upper electrode and the first lower electrode and between the second upper electrode and the second lower electrode, such that the first filter structure and the second filter structure Move toward the substrate. The tunable filter element of claim 1, further comprising: a first frame structure, the first filter structure being coupled to the first frame structure, wherein the first frame structure is along a first axis Connecting to the first elastic unit, and the first upper electrode is disposed beside the first filter structure; and a second frame structure, the second filter structure is coupled to the second frame structure, wherein the second The frame structure is respectively connected to the second elastic unit along a first axial direction and a second axial direction perpendicular to the first axial direction, and the second upper electrode is disposed on the second filter Next to the light structure. The tunable filter element of claim 1, wherein the substrate layer is a transparent substrate layer. The tunable filter element of claim 1, wherein the first reflective film and the second reflective film are distributed Bragg reflectors. The tunable filter element of claim 1, wherein the first filter structure comprises a first filter layer and a third reflective film, and the second filter structure comprises a second filter The layer and a fourth reflective film are located between the first filter layer and the substrate, and the fourth reflective film is located between the second filter layer and the substrate. A method for fabricating an adjustable filter element, comprising: forming a reflective film substrate layer; providing a wafer substrate, the wafer substrate comprising a germanium substrate, an insulating layer and a substrate layer; and a surface of the germanium substrate Forming a nitride layer thereon; etching the nitride layer to expose a portion of the surface of the germanium substrate; forming at least one support mount and a barrier layer on the germanium substrate, wherein the barrier layer is located at the support Between the sockets, a first filter structure, a second filter structure, a first upper electrode, a second upper electrode and a second metal line are respectively formed on the substrate, wherein the first upper electrode is connected To the first filter structure, the second upper electrode is connected to the second filter structure; Bonding the germanium substrate and the substrate layer, wherein the first filter structure faces the first reflective film, the second filter structure faces the second reflective film; and respectively forms a first elastic unit and a second elastic The unit is disposed on the substrate, wherein the first elastic unit is connected to the first filter structure and a portion of the support holders, and the second elastic unit is connected to the second filter structure and other portions of the support holders. The method of fabricating the tunable filter element of claim 8, wherein the method of forming the substrate layer comprises: forming a first lower electrode, a second lower electrode, and a first on a substrate Forming a protective oxide layer on the substrate; forming a plurality of via windows on the protective oxide layer to expose a portion of the surface of the substrate, the protective oxide layer covering the first lower electrode, the second lower portion An electrode and a region of the metal line; and a first reflective film and a second reflective film are respectively formed on the substrate, wherein the first reflective film and the second reflective film are respectively located in the via window. The method of fabricating the tunable filter element of claim 8, wherein the forming the first elastic unit and the second elastic unit on the cymbal substrate comprises: forming a first a frame structure, the first filter structure is coupled to the first frame structure, wherein the first frame structure is coupled to the first elastic unit along a first axial direction, and the first upper electrode is disposed on the first filter Next to the light structure; Forming a second frame structure on the substrate, the second filter structure is coupled to the second frame structure, wherein the second frame structure is along the first axial direction and a second portion perpendicular to the first axial direction The second elastic unit is axially connected, and the second upper electrode is disposed beside the second filter structure. The method of fabricating the tunable filter element of claim 8, wherein the method of forming the first filter structure and the second filter structure on the ruthenium substrate comprises: respectively Forming a first filter layer and a second filter layer, wherein the first upper electrode is connected to the first filter layer, the second upper electrode is connected to the second filter layer; and the first filter layer and the first filter layer A third reflective film and a fourth reflective film are respectively formed on the second filter layer.