TW202218197A - Temperature sensing device and the manufacturing method thereof - Google Patents

Abstract

A sensing device is provided. The sensing device includes a substrate having a first side, and a second side opposite the first side, wherein the first side has a groove; an infrared energy absorbing unit disposed on the groove, and including plural metal layers and plural dielectric layers stacked on top of each other, and a thermocouple, wherein the uppermost metal layer includes a combination of array metal geometrical patterns, and the combination of array metal geometrical patterns includes plural array metal geometrical patterns having specific sizes and shapes; and a temperature sensing unit disposed around the first side, wherein the thermocouple is coupled to the temperature sensing unit.

Description

Temperature sensing device and manufacturing method thereof

The present invention relates to a sensing device and a manufacturing method thereof, in particular to a temperature sensing device and a manufacturing method thereof.

The application of infrared sensors is quite popular in daily life. Most of the early technologies use photonic components as infrared sensors, and photonic sensors include photoconductive and photoresistive types. Photonic sensors have high response It has the advantages of high speed and rapid response of components, but it cannot absorb large wavebands. In addition, the epitaxial process of the photonic sensor is complicated, so the manufacturing cost is quite high.

Another thermal infrared sensor uses infrared absorption into heat for sensing. Compared with photonic sensors, the infrared absorption band is wider, and with the maturity of semiconductor manufacturing process and MEMS technology, thermal infrared sensor performance improvement, size reduction, high-volume manufacturing, and cost reduction of the tester Factors, thermal infrared sensor is the main direction of the recent infrared sensor development.

Thermal infrared sensors can be classified into a pyroelectric type, a thermoelectric type, and a thermistor type (Bolometer) according to the sensing principle. The responsivity of the pyroelectric infrared sensor is related to the temperature change rate. After the electric dipole moment inside the material is balanced, there will be no signal output, and only the AC signal can be measured. The pyroelectric infrared sensor utilizes the temperature difference between the two ends of the pyroelectric material to make the electron concentration at the two ends of the material different to form a potential difference. Traditionally, pyroelectric infrared sensors are larger in size and less responsive. The thermistor infrared sensor uses materials with high temperature resistivity to sense temperature, but it needs to supply operating voltage or current during operation, and the component itself will generate Joule heat, which is prone to errors.

Whether it is a photonic or thermal infrared sensor, each has its own advantages and disadvantages. For the development of infrared sensors, it is nothing more than miniaturization, low power consumption, cost reduction, and performance improvement. At present, the MEMS process and the semiconductor process are integrated and improved, and the problem of low responsivity of the pyroelectric infrared sensor is expected to be improved.

For this reason, in view of the deficiencies of the prior art, the applicant invented the present "temperature sensing device and its manufacturing method" to improve the above deficiencies. lose.

One aspect of the present application is to provide a sensing device, which includes a substrate having a first side and a second side opposite to the first side, wherein the first side has a groove; an infrared energy absorbing unit provided with On the trench, it includes a plurality of metal layers and a plurality of dielectric layers stacked alternately with each other, and a thermocouple, wherein the uppermost metal layer includes an array of metal geometric pattern combinations, and the array metal geometric pattern combination includes a plurality of an array metal geometric pattern of specific size and shape; and a temperature sensing unit disposed around the first side, wherein the thermoelectricity is coupled to the temperature sensing unit.

Another aspect of the present application is to provide a method of manufacturing a sensing device, comprising the steps of: providing a substrate having a first side and a second side opposite to the first side, and the first side has a trench; an infrared energy absorption unit is formed on the trench, wherein the infrared energy absorption unit includes a plurality of metal layers, a plurality of dielectric layers and a thermocouple, and the uppermost metal layer includes an array of metal layers. a geometric pattern combination, and the array metal geometric pattern combination includes a plurality of array metal geometric patterns with a specific size and shape; and a temperature sensing unit is formed on the first side around, wherein the thermoelectric coupling is coupled to the temperature sensing unit.

Another aspect of the present application is to provide a sensing device including a substrate; an infrared energy absorption unit having an upper part, wherein the upper part includes an upper metal layer; a lower metal layer; and a dielectric layer disposed on the upper and lower parts between metal layers; and a plurality of electric dipole moment resonant media, disposed between the upper and lower metal layers, so that each of the electric dipole moment resonance media respectively enables the dielectric layer to absorb light energy in the spectral range we desire; and a The thermocouple is arranged between the substrate and the infrared energy absorption unit.

10: Sensing device

11: Substrate

13: Metal layer

14: External metal traces

15: Upper metal layer

16: Dielectric layer

17: Lower metal layer

19: Connecting Metals

20: Infrared absorption unit

21: The upper part of the infrared absorption unit

22: Plasmonic metamaterial absorber layer

30: Temperature sensing unit

31: Thermocouple

32: Heat transfer structure

33: Winding thermal resistance

35: Groove

FIG. 1 is a three-dimensional schematic diagram of a temperature sensing device according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of FIG. 1 .

FIG. 3 shows the thermocouple of FIG. 1 .

FIG. 4 is a schematic diagram of an array metal geometric pattern combination.

FIG. 5 is a schematic cross-sectional view of an array metal geometric pattern combination.

6A-6B show that the upper metal layer is in a cross-shaped pattern.

7A-7B show that the upper metal layer is in a circular pattern.

8A-8D show the fabrication of a pyroelectric infrared temperature sensing device Procedure.

Figure 9A shows the simulated spectrum of the array metal cross pattern

Figure 9B shows the simulated spectrum of the array metal circular pattern

Figure 10 shows the band design of the metamaterial absorber layer between 8 and 14 μm

The idea of this case is to use the existing CMOS process platform. The CMOS process platform has a structure in which multi-layer metal layers and multi-layer polysilicon layers are alternately stacked to fabricate a MEMS thermoelectric temperature sensing unit. The metal layer, dielectric layer, and metal layer of the CMOS process platform are stacked into a sandwich structure, and the MEMS structure is used. It can make a plasmonic metamaterial absorption layer, imitate the electric coupling moment resonance in the dielectric material, and adjust the geometric size of the micro-electromechanical structure to change the absorption band or absorption, thereby improving the absorption of infrared rays. capability, and improve the sensitivity of the temperature sensing unit. The dielectric layer in the original structure can be SíO ₂ , Sí ₃ N ₄ , etc. The dielectric layer itself can also absorb infrared light by virtue of its own molecular bond resonance properties.

Please refer to FIG. 1, which is a three-dimensional schematic diagram of a temperature sensing device (10) according to an embodiment of the present invention. The temperature sensing device (10) comprises a substrate (11), a temperature sensing unit (30), and an infrared absorption unit (20).

Please refer to FIG. 2 and FIG. 3 , FIG. 2 is a schematic cross-sectional view of FIG. 1 , and FIG. 3 shows the thermocouple of FIG. 1 . The temperature sensing device (10) comprises a substrate (11) and an infrared energy absorption unit (20). One side of the substrate (11) has a groove (35), the infrared energy absorption unit (20) is arranged on the groove (35), and the groove (35) is used to isolate the substrate (11) from the infrared rays The energy absorbing unit (20) concentrates the thermal energy absorbed by the infrared energy absorbing unit (20) and reduces the dissipation from the substrate (11). The infrared energy absorbing unit (20) comprises a plurality of metal layers (13) and a plurality of dielectric layers (16) stacked alternately with each other, and a thermocouple (31), and the upper part (21) of the infrared energy absorbing unit has a The sandwich structure formed by stacking the metal layer (15), the dielectric layer (16), and the lower metal layer (17) is called a plasmonic metamaterial absorption layer (22). The uppermost metal layer (15) comprises an array of metal geometric pattern combinations (40), as shown in FIG. 4 . The array metal geometric pattern combination (40) includes a plurality of array metal geometric patterns (41), (42) with specific sizes and shapes, and the array metal geometric patterns (41), (42) are used as electric dipole moment resonance media, so as to Improve the ability of the component to absorb infrared rays and improve the sensitivity of the sensing device.

When the infrared energy absorption unit (20) absorbs infrared rays, its temperature will rise, and due to the pyroelectric effect, the carrier concentration inside the infrared energy absorption unit (20) will also increase accordingly to generate current, and the temperature sensing unit (30) is used to measure the temperature. Measurement. The temperature sensing unit (30) has a thermocouple structure (31) and a heat transfer structure (32), wherein the heat transfer structure (32) is a polysilicon layer. The thermocouple structure (31) includes an aluminum-copper metal, an N-type polysilicon, or a P-type polysilicon silicon, and is a long strip thermal resistance or a winding thermal resistance (33). The heat transfer structure (32) connects the current to the multi-layer metal layer (13) through the connecting metal (19), and transmits the signal to the outside of the temperature sensing device (10) through the external metal wiring (14).

The upper part (21) of the infrared energy absorption unit (20) is shown in Fig. 2, which has a sandwich structure formed by stacking an upper metal layer (15), a dielectric layer (16), and a lower metal layer (17). , as shown in Figure 5, is called the plasmonic metamaterial absorber layer (22). Plasmonic metamaterials are artificial materials constructed by arrayed subwavelength structures, which can alter optical properties by changing geometric dimensions or material selection. The plasmonic metamaterial absorption layer (22) in this case is composed of an upper-layer wavelength metal antenna, a middle-layer dielectric layer and a lower-layer metal reflection layer. The electrons in the upper-layer wavelength metal antenna move in the opposite direction of the electric field, forming plasmonic resonance, and generating electric coupling moment resonance with the lower metal reflective layer. According to the requirements of the absorption band, the upper metal layer (15), the dielectric Layer (16), and underlying metal layer (17) geometry and dimensions.

When the plasmonic metamaterial absorption layer (22) is designed in the coupling region, that is, the electric dipole moments of the plasmonic metamaterial absorption layer (22) and the intermediate dielectric layer are generated at the same time, and the two have Coulomb force to generate coupling It is a phenomenon that the absorption wavelength does not increase linearly with the geometric size of the antenna, but is determined by the coupling of the two electric dipole moments to generate two characteristic frequencies. The absorption peak and peak spacing of the plasmonic metamaterial absorption layer (22) can be calculated and adjusted using the following formulas.

△ω為兩特徵頻率的間距，在偶合區的吸收頻率將受偶合強度V及金 屬層-介電層-金屬層(MIM)超材吸收層(22)與介電層(16)在非偶合區的性質(ω_MIM、ω₀、γ_MIM、γ₀)影響，因此可透過設計這些參數來調整超材料吸收層(22)在偶合區的吸收峰值和峰值間距。

△ω is the distance between the two characteristic frequencies, the absorption frequency in the coupling region will be affected by the coupling strength V and the metal-dielectric-metal (MIM) metamaterial absorption layer (22) and the dielectric layer (16) in the non-coupling region. The properties of the region (ω _MIM , ω ₀ , γ _MIM , γ ₀ ) are affected, so the absorption peak and peak spacing of the metamaterial absorber layer (22) in the coupling region can be adjusted by designing these parameters.

The uppermost metal layer (15) comprises an array of metal geometric pattern combinations (40), as shown in FIG. 4 . The array metal geometric pattern combination (40) includes a plurality of array metal geometric patterns (41), (42) with specific sizes and shapes, and the pattern may be a cross pattern (41) or a circular pattern (42), but not only limited. The cross-shaped pattern (41) is a pair of vertical axes, the line width d of the axes is between 0.5 and 1.5 micrometers, and the line length l is between 1.5 and 4 micrometers; and the diameter D of the circular pattern (42) It is between 1.5 and 4 microns, and its simulated spectrum shows three absorption peaks, as shown in Figures 9A-9B.

When the line width d of the axis is between 0.5 and 1.5 microns, and the line length l is between 1.5 and 4 microns, or the diameter D of the circular pattern is between 1.5 and 4 microns, and the upper metal layer ( When the dielectric layer (16) between 15) and the lower metal layer (17) is silicon dioxide (as shown in Figure 5), the resulting coupling absorption peak is between 12 and 19 microns, while the silicon dioxide dielectric The electric layer (16) absorbs infrared light by utilizing the resonance characteristic of molecular bonds, and has an absorption phenomenon at wavelengths of 8.14 microns and 9.51 microns. It can be seen from this that if the wavelength band of the metamaterial absorption layer (22) is designed to be in the 8 to 14 micron band (as shown in Figure 10), the dielectric layer ( 16) There will also be an absorption phenomenon, so the coupling effect can be taken into consideration when fabricating the plasmonic metamaterial absorption layer (22).

Therefore, the cross-shaped pattern (41) (as shown in Figs. 6A-6B) is selected to have an axis line width d between 0.5 and 1.5 microns, a line length l of 2.5 microns, and a circular pattern with a diameter D of 1.5 microns ( 42) (as shown in Figures 7A-7B), the transmission spectrum is linearly superimposed to achieve a relatively flat absorption spectrum in the wavelength range of 8 to 14 microns. The 8 to 14 micron waveband is required for human body sensing, and the axis line width d is 1 micron, the line length l is 2.5 microns, and with a circular pattern (42) with a diameter D of 1.5 microns, it is the best value . Through the plasmonic metamaterial absorbing layer (22) of different pattern arrays, the infrared absorption rate can be improved in the target wavelength band between 8 and 14 microns, and compared with the design without the plasmonic metamaterial absorbing layer (22), the absorption rate of infrared rays can be improved. The loudness of the element is improved by more than 20%, and the detection capability is improved by 21% compared with the design without the plasmonic metamaterial absorption layer (22).

The upper metal layer (15) and the upper metal layer (17) in the infrared energy absorption unit (20) may be aluminum-copper alloys, but not limited thereto. The dielectric layer (16) can be silicon dioxide SiO ₂ or silicon nitride Si ₃ N ₄ , but not limited thereto, and silicon dioxide SiO ₂ is commonly used as the material of the dielectric layer ( 16 ), and silicon dioxide SiO 2 ₂ has an absorption wavelength between 8.14 microns and 9.51 microns. In order to increase the range of absorption wavelengths, the plasmonic metamaterial absorption layer (22) in the infrared energy absorption unit (20) is used to repeatedly resonate the incident light in the absorption layer (22) to achieve absorption in a specific wavelength band. In the present invention, the metal layer (15) on the uppermost layer is used to etch metal geometric patterns (41), (42) with specific sizes and shapes, and the size and size of the metal geometric patterns (41) and (42) are adjusted. shape to achieve the absorption of a specific waveband.

The manufacturing process of the pyroelectric infrared temperature sensing unit (30) is shown in the figure 8A-8D shown. As shown in FIG. 8A , a CMOS wafer is subjected to wet etching of metal using sulfuric acid etchant and hydrogen peroxide at 150 degrees Celsius, and the metal sacrificial layer in the wafer is removed to define the area of the pyroelectric infrared sensor, as shown in the figure 8B. Then, isotropic dry etching of xenon fluoride (XeF2) is performed on the area defined by the previous process, and the silicon substrate under the infrared absorption unit (20) is hollowed out by dry etching, so that the infrared absorption unit (20) is hollowed out by dry etching. ) is suspended to achieve the effect of thin film thermal insulation, as shown in FIG. 8C , so that the sensitivity of the temperature sensing unit (30) can be improved. Finally, the silicon dioxide above the infrared absorption unit (20) is removed by reactive ion etching to form an upper metal layer (15), and the metal geometric patterns (41), (42) with special shapes and sizes are exposed , as shown in FIG. 8D, then connect the external metal trace (14) for signal measurement.

Example:

1. A sensing device comprising:

a substrate having a first side and a second side opposite to the first side, wherein the first side has a groove;

An infrared energy absorbing unit is disposed on the trench, and includes a plurality of metal layers and a plurality of dielectric layers stacked alternately with each other, and a thermocouple, wherein the uppermost metal layer includes an array of metal geometric pattern combinations, and the array Metal geometric pattern set contains multiple tools Arrayed metallic geometric patterns of specified size and shape; and

A temperature sensing unit is disposed around the first side, wherein the thermoelectric coupling is coupled to the temperature sensing unit.

2. The sensing device of embodiment 1, wherein:

The temperature sensing unit has a thermocouple structure and a heat transfer structure;

The thermocouple structure includes an aluminum-copper metal, an N-type polysilicon, or a P-type polysilicon, and is a long strip thermal resistance or a winding thermal resistance; and

The heat transfer structure conducts current to the outside of the sensing device.

3. The sensing device according to embodiments 1-2, wherein the material of the dielectric layer is SiO ₂ or Si ₃ N ₄ .

4. The sensing device according to embodiments 1-3, wherein the array metal geometric pattern is a cross-shaped pattern or a circular pattern.

5. The sensing device of embodiments 1-4, wherein:

The size of the cross-shaped pattern is 1.5-4 microns;

The line width of the cross-shaped pattern is 0.5-1.5 microns; and

The diameter of the circular pattern is 1.5-4 microns.

6. The sensing device of embodiments 1-5, wherein the infrared energy absorption unit enables the dielectric layer to absorb infrared energy with wavelengths ranging from 7 to 15 microns by using the array of metal geometric patterns.

7. A method of manufacturing a sensing device, comprising the steps of:

providing a substrate, the substrate has a first side and a second side opposite to the first side, and the first side has a groove;

forming an infrared energy absorbing unit on the trench, wherein the infrared energy absorbing unit includes a plurality of metal layers and a plurality of dielectric layers and a thermocouple stacked alternately with each other, and the uppermost metal layer includes an array of metal geometric pattern combinations, and the array metal geometric pattern combination includes a plurality of array metal geometric patterns having a specific size and shape; and

A temperature sensing unit is formed around the first side, wherein the thermoelectric coupling is coupled to the temperature sensing unit.

8. The method of embodiment 7, wherein:

The temperature sensing unit has a thermocouple structure and a heat transfer structure;

The thermocouple structure includes an aluminum-copper metal, an N-type polysilicon, or a P-type polysilicon, and is a long strip thermal resistance or a winding thermal resistance;

the heat transfer structure conducts current to the outside of the sensing device;

The material of the dielectric layer is SiO ₂ or Si ₃ N ₄ ;

The array metal geometric pattern is a cross pattern or a circular pattern;

The infrared energy absorption unit enables the dielectric layer to absorb infrared energy with wavelengths ranging from 7 to 15 microns by using the array metal geometric pattern array;

The size of the cross-shaped pattern is 1.5-4 microns;

The line width of the cross-shaped pattern is 0.5-1.5 microns; and

The diameter of the circular pattern is 1.5-4 microns.

9. A sensing device comprising:

a substrate;

An infrared energy absorbing unit having an upper portion, wherein the upper portion includes:

a metal layer;

next metal layer;

a dielectric layer disposed between the upper and lower metal layers; and

a plurality of electric dipole moment resonant media, disposed between the upper and lower metal layers, so that each of the electric dipole moment resonance media respectively enables the dielectric layer to absorb light energy in a desired spectral range; and

A thermocouple is arranged between the substrate and the infrared energy absorption unit.

10. The sensing device of embodiment 9, wherein each of the electric dipole moment resonance mediators is a patterned cell on the upper metal layer.

11: Substrate

13: Metal layer

14: External metal traces

15: Upper metal layer

16: Dielectric layer

17: Lower metal layer

19: Connecting Metals

20: Infrared absorption unit

21: The upper part of the infrared absorption unit

22: Plasmonic metamaterial absorber layer

35: Groove

Claims (10)

A sensing device, comprising: a substrate having a first side and a second side opposite to the first side, wherein the first side has a groove; An infrared energy absorbing unit is disposed on the trench, and includes a plurality of metal layers and a plurality of dielectric layers stacked alternately with each other, and a thermocouple, wherein the uppermost metal layer includes an array of metal geometric pattern combinations, and the array The metal geometric pattern combination includes a plurality of arrayed metal geometric patterns having a specific size and shape; and A temperature sensing unit is disposed around the first side, wherein the thermoelectric coupling is coupled to the temperature sensing unit. The sensing device of claim 1, wherein: The temperature sensing unit has a thermocouple structure and a heat transfer structure; The thermocouple structure includes an aluminum-copper metal, an N-type polysilicon, or a P-type polysilicon, and is a long strip thermal resistance or a winding thermal resistance; and The heat transfer structure conducts current to the outside of the sensing device. The sensing device according to claim 1, wherein the material of the dielectric layer is SiO ₂ or Si ₃ N ₄ . The sensing device of claim 1, wherein the array metal geometric pattern is a cross-shaped pattern or a circular pattern. The sensing device of claim 4, wherein: The size of the cross-shaped pattern is 1.5-4 microns; The line width of the cross-shaped pattern is 0.5-1.5 microns; and The diameter of the circular pattern is 1.5-4 microns. The sensing device of claim 1, wherein the infrared energy absorption unit enables the dielectric layer to absorb infrared energy with wavelengths ranging from 7 to 15 microns by using the array metal geometric pattern array. A method of manufacturing a sensing device, comprising the following steps: providing a substrate, the substrate has a first side and a second side opposite to the first side, and the first side has a groove; forming an infrared energy absorbing unit on the trench, wherein the infrared energy absorbing unit includes a plurality of metal layers and a plurality of dielectric layers and a thermocouple stacked alternately with each other, and the uppermost metal layer includes an array of metal geometric pattern combinations, and the array metal geometric pattern combination includes a plurality of array metal geometric patterns having a specific size and shape; and A temperature sensing unit is formed around the first side, wherein the thermoelectric coupling is coupled to the temperature sensing unit. The method of claim 7, wherein: The temperature sensing unit has a thermocouple structure and a heat transfer structure; The thermocouple structure includes an aluminum-copper metal, an N-type polysilicon, or a P-type polysilicon, and is a long strip thermal resistance or a winding thermal resistance; the heat transfer structure conducts current to the outside of the sensing device; The material of the dielectric layer is SiO ₂ or Si ₃ N ₄ ; The array metal geometric pattern is a cross pattern or a circular pattern; The infrared energy absorption unit enables the dielectric layer to absorb infrared energy with wavelengths ranging from 7 to 15 microns by using the array metal geometric pattern array; The size of the cross-shaped pattern is 1.5-4 microns; The line width of the cross-shaped pattern is 0.5-1.5 microns; and The diameter of the circular pattern is 1.5-4 microns. A sensing device, comprising: a substrate; An infrared energy absorbing unit having an upper portion, wherein the upper portion includes: a metal layer; next metal layer; a dielectric layer disposed between the upper and lower metal layers; and a plurality of electric dipole moment resonant media, disposed between the upper and lower metal layers, such that each of the electric dipole moment resonance media respectively enables the dielectric layer to absorb light energy in our desired spectral range; and A thermocouple is arranged between the substrate and the infrared energy absorption unit. The sensing device of claim 9, wherein each of the electric dipole moment resonant media is at the One of the patterned cells on the upper metal layer.

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