WO2016095600A1

WO2016095600A1 - Three-dimensional temperature detector and manufacturing method thereof

Info

Publication number: WO2016095600A1
Application number: PCT/CN2015/091662
Authority: WO
Inventors: 费跃; 王旭洪; 张颖
Original assignee: 上海新微技术研发中心有限公司
Priority date: 2014-12-18
Filing date: 2015-10-10
Publication date: 2016-06-23
Also published as: CN104501970A; CN104501970B

Abstract

A three-dimensional temperature detector and a preparation method thereof, the vertical temperature detector comprising: a substrate (9); a first dielectric layer (10) on a surface of the substrate; a cavity (22) surrounded by the first dielectric layer (10), a first layer of a thermopile material structure (12), a second dielectric layer structure (14), a second layer of the thermopile material structure (17) and a third layer of the dielectric layer structure; a bottom of the cavity (22) has a sixth groove (18b) and an infrared absorbing layer structure (20) filling the sixth groove (18b), the infrared absorbing layer structure (20) having an eighth groove (21); the first layer of the thermopile material structure (12) is connected to the second layer of the thermopile material structure (17) via a fourth groove (16). The vertical temperature detector can increase thermocouple pairs of the thermopile and length of the thermopile heat insulation film, reducing thermal conductivity, thus increasing temperature difference between the heat junction and the cold junction and improving sensitivity of the temperature detector, furthermore, improving process stability and device performance in the manufacturing process.

Description

Three-dimensional temperature detector and manufacturing method thereof

Technical field

The present application relates to the field of semiconductor technology, and in particular, to a stereoscopic temperature detector and a method of fabricating the same.

Background technique

Temperature detection has always been a hot topic in the sensor industry, and infrared detection technology is more popular among designers, manufacturers and users for its non-contact temperature measurement. As a kind of infrared detector, thermopile temperature sensor is widely studied because of its simple manufacturing process, low cost, convenient use and no 1/f noise.

The main working principle of the thermopile temperature sensor is the Seebeck effect. The effect can be briefly described as follows: two materials with different Seebeck coefficients (α1, α2) are connected at one end and open at one end. If there is a temperature difference ΔT=T1-T2 at both ends, an open circuit potential ΔV will be generated at the open end. The Seebeck effect. The structure constitutes a thermocouple. If N thermocouples are connected in series to form a thermopile, a larger thermoelectric potential can be generated than a single thermocouple, that is, ΔV = N * (α1 - α2) * ΔT.

The thermopile temperature sensor has three types of closed membranes, cantilever beams and suspension structures according to its design. Among them, the cantilever beam and suspension structure process is difficult, and the yield is not high in large-scale production. Therefore, the prior art adopts a closed membrane structure for design and production.

In the prior art, the closed-film thermopile temperature sensor needs to pass through the double as shown in FIG. The back side of the surface process etches the silicon material 1 to form the recesses 6 or forms the cavity 8 by front opening wet etching or dry etching as shown in FIG. There is a

film

5 or 7 above the groove or cavity, and the hot junction of the thermopile 2 is placed in the center of the film to receive the heat generated by the infrared radiation on the absorption layer 3 on the

film

5 or 7, and the cold junction is placed on the silicon liner. Thermal short circuit on bottom 4 or 6a, keeping the same temperature as ambient.

It should be noted that the above description of the technical background is only for the purpose of facilitating a clear and complete description of the technical solutions of the present application, and is convenient for understanding by those skilled in the art. The above technical solutions are not considered to be well known to those skilled in the art simply because these aspects are set forth in the background section of this application.

Summary of the invention

The inventors of the present application have found that, for the structure of FIG. 1, the double-sided process lithography alignment accuracy is not high, and the actual manufacturing process is easy to be biased, resulting in device failure or performance degradation; for the structure of FIG. 2, the front etch technology is Wet etching (such as KOH, TMAH etching, etc.) or dry etching (such as XeF ₂ ) is difficult to accurately control the etching depth and width, thus affecting device performance. In addition, since the size of the sensor is limited in consideration of the device size and the yield of the sensor on the unit wafer, the size of the planar film is also limited, so the thermal conductivity between the hot junction and the cold junction is increased, the heat junction and The temperature difference of the cold junction is not large enough, and the sensitivity of the sensor to detect the temperature is not high.

The present application proposes a three-dimensional temperature detector and a manufacturing method thereof, and a cavity structure is formed by microfabrication sacrificial layer technology, and a hot junction and a cold junction are respectively disposed on the outer side of the top and bottom of the cavity structure, thereby Applied stereoscopic temperature detector and flat in the prior art Compared with the surface film type temperature detector, in the same area, the length of the thermopile thermocouple pair and the thermopile insulation film can be increased, the thermal conductivity is lowered, and the temperature difference between the hot junction and the cold junction is increased, and the temperature is increased. The sensitivity of the detector; and, in the manufacturing process of the stereoscopic temperature detector, the influence of the alignment error in the double-sided process can be avoided, and the influence of the over-etch in the front etching process can be avoided, thereby improving the device performance and Process stability.

According to an aspect of an embodiment of the present application, a method for manufacturing a stereoscopic temperature detector is provided, the method comprising:

Depositing a first dielectric layer (10) on the substrate (9);

Forming a sacrificial layer structure (11) on the first dielectric layer (10);

Forming a first layer of thermopile material structure (12) on an upper surface and a sidewall of the sacrificial layer structure (11), the first layer of thermopile material structure (12) having an upper surface of the sacrificial layer structure a portion of the exposed first recess (13), and the first layer of thermopile material structure (12) further has a first extension (12b), the first extension (12b) covering the sacrificial layer structure (11) a portion of the first dielectric layer (10) on the outside of the bottom;

Forming a second dielectric layer structure (14) to cover the surface of the first layer of thermopile material structure (12) and the exposed surface of the first dielectric layer (10), the second dielectric layer structure (14) having a second groove (14b), a third groove (15) and a fourth groove (16), wherein the second groove (14b) exposes the first groove (13), the third a recess (15) exposing a portion of the first extension (12b), the fourth recess (16) aligning the first layer of thermopile material structure outside the first recess (13) a part of (12) is exposed;

Forming a second layer of thermopile material structure (17) to cover the second dielectric layer structure (14), the second layer thermopile material structure (17) is connected to the first layer thermopile material structure (12) through the fourth groove (16), the second layer thermopile material structure (17) having a fifth groove (17b) and a second extension (17c), wherein the fifth groove (17b) exposes the first groove (13), the second extension ( 17c) a surface of the second dielectric layer structure (14) covering a portion of the first dielectric layer (10);

Forming a third dielectric layer structure (18) to cover the second layer thermopile structure (17), the third dielectric layer structure (18) having a sixth recess exposing the first recess (13) (18b), and a seventh recess (19) exposing a portion of the second extension (17c);

Forming an infrared absorbing layer structure (20) filling the sixth recess (18b), the infrared absorbing layer structure (20) having an eighth recess exposing a portion of an upper surface of the sacrificial layer structure (11) (twenty one);

The sacrificial layer structure is removed via the eighth recess (21) to form a cavity (22).

According to another aspect of the embodiments of the present application, wherein

The first layer of thermopile material structure (12) has adjacent at least two, the second layer of thermopile material structure (17) has adjacent at least two, and the second layer of thermopile material The structure (17) is coupled to the adjacent first layer of thermopile material structures (12) via the third recess (15) to form a series of thermocouple pairs.

The material of the infrared absorbing layer is titanium (Ti), titanium nitride (TiN), tantalum (Ta), tantalum nitride (TaN), gold black (black black), silicon black (silica black) and dielectric layer composite film. One or more of them.

The first layer thermopile material structure and the second layer thermopile material structure are doped polysilicon, bismuth (Sb) and its compound, bismuth (Bi) and its compound, titanium (Ti) and its compound, bismuth, respectively. (Ta) and one of its compounds, aluminum (Al) and gold (Au);

And, the first layer of thermopile material structure and the second layer of thermopile material structure have different Seebeck coefficients.

The ratio of the lateral area of the eighth groove (21) to the lateral area of the infrared absorbing layer structure (20) is 1:10000-1:1000000.

The sacrificial layer structure (11) has a thickness of 0.1 um to 100 um.

The lateral area of the sixth groove (18b) is smaller than the lateral area of the first groove (13).

According to still another aspect of the embodiments of the present application, a stereoscopic temperature detector is provided, including:

Substrate (9);

a first dielectric layer (10) on a surface of the substrate (9);

a first layer of thermopile material structure (12), a second dielectric layer structure (14), and a second layer of thermopile material structure (17) stacked on the surface of the first dielectric layer (10) in this order from bottom to top And a third dielectric layer structure (18), and the first dielectric layer (10), the second dielectric layer structure (14), and the third dielectric layer structure (18) are enclosed Cavity (22);

The top of the cavity has a sixth recess (18b) and an infrared absorbing layer structure (20) filling the sixth recess (18b), the infrared absorbing layer structure (20) having the cavity (22) An eighth groove (21) communicating with the outside;

The second dielectric layer structure (14) has a third recess (15) and a fourth recess (16), the fourth recess (16) being located at the top of the cavity (22) and located at the The outer side of the sixth recess (18b), the third recess (15) is located outside the bottom of the cavity (22), and the second layer of thermopile material structure (17) passes through the A four groove (16) is coupled to the first layer of thermopile material structure (12).

The utility model has the beneficial effects that the cavity structure is formed by the micro-machining sacrificial layer technology, and the hot junction and the cold junction are respectively disposed on the outer side of the top and bottom of the cavity structure, thereby increasing the temperature difference between the hot junction and the cold junction. Improve the sensitivity of the temperature detector and improve device performance and process stability.

Specific embodiments of the present application are disclosed in detail with reference to the following description and accompanying drawings, in which <RTIgt; It should be understood that the embodiments of the present application are not limited in scope. The embodiments of the present application include many variations, modifications, and equivalents within the scope of the appended claims.

Features described and/or illustrated with respect to one embodiment may be used in one or more other embodiments in the same or similar manner, in combination with, or in place of, features in other embodiments. .

It should be emphasized that the term "comprising" or "comprises" or "comprising" or "comprising" or "comprising" or "comprising" or "comprises"

DRAWINGS

The drawings are included to provide a further understanding of the embodiments of the present application, and are intended to illustrate the embodiments of the present application Obviously, the drawings in the following description are only some of the embodiments of the present application, and those skilled in the art can obtain other drawings according to the drawings without any inventive labor. In the drawing:

1 is a schematic perspective view showing a closed-film thermopile temperature sensor manufactured by a double-sided process;

2 is a schematic perspective view showing a closed-film thermopile temperature sensor manufactured by a front etching process;

3 is a schematic top plan view of a three-dimensional temperature detector according to an embodiment of the present application;

4 is a schematic longitudinal sectional structural view of a three-dimensional temperature detector according to an embodiment of the present application;

5 is a schematic side view showing the structure of a three-dimensional temperature detector according to an embodiment of the present application;

6 is a schematic flow chart of a method for manufacturing a stereoscopic temperature detector according to an embodiment of the present application;

7A-7O are schematic structural views of devices corresponding to each step of the method for manufacturing a three-dimensional temperature detector according to an embodiment of the present application.

detailed description

The foregoing and other features of the present application will be apparent from the description, The specific embodiments of the present application are specifically disclosed in the specification and the drawings, which illustrate some embodiments in which the principles of the present application may be employed, it should be understood that The application is not limited to the described embodiments, but rather, all modifications, variations and equivalents are intended to be included within the scope of the appended claims.

In the present application, for the convenience of explanation, the surface on which the respective dielectric layers of the substrate are disposed is referred to as "upper surface", and the surface of the substrate opposite to the "upper surface" is referred to as "lower surface", whereby " The "up" direction refers to the direction from the "lower surface" to the "upper surface", the "lower" direction is opposite to the "upper" direction, and the "upper" direction and the "down" direction are collectively referred to as "longitudinal". The direction in which the "upper surface" of the semiconductor is parallel is referred to as "lateral". It should be noted that, in the present application, the "upper" and "lower" settings are relative, but for convenience of explanation, and do not represent the orientation when the stereoscopic temperature detector is specifically used or manufactured.

Example 1

Embodiment 1 of the present application provides a method of manufacturing a stereoscopic temperature detector. 6 is a schematic flow chart of the manufacturing method of the three-dimensional temperature detector, and FIG. 7 is a schematic longitudinal cross-sectional view of the device structure corresponding to each step of the manufacturing method of the three-dimensional temperature detector. Next, a method of manufacturing the three-dimensional temperature probe of the present embodiment will be described with reference to Figs. 6 and 7.

Step S601: depositing a first dielectric layer 10 on the substrate 9, as shown in Fig. 7A.

In this embodiment, the substrate may be a wafer commonly used in the semiconductor manufacturing field, such as a silicon wafer, a silicon-on-insulator (SOI) wafer, a silicon wafer, a germanium wafer, or Gallium Nitride (GaN) wafers and the like are not limited in this embodiment.

In this embodiment, a thin film deposition method commonly used in a semiconductor manufacturing process can be employed. The first dielectric layer 10 is deposited on the substrate 9, and the first dielectric layer 10 is used to electrically insulate the substrate 9 from the thermopile structure.

Step S602: forming a sacrificial layer structure 11 on the first dielectric layer 10.

In this embodiment, the step S602 may include the following steps:

1) Spin coating the sacrificial layer.

A sacrificial layer 11a is formed by spin coating on the surface of the first dielectric layer 10 and curing at a high temperature, as shown in Fig. 7B.

2) Forming a sacrificial layer structure.

The sacrificial layer pattern is formed by reticle lithography, and the pattern is etched to form a sacrificial layer structure 11 for forming a cavity of a stereoscopic temperature detector to be described later, as shown in Fig. 7C.

In this embodiment, the lateral width of the sacrificial layer structure 11 is similar to that of the thermopile recess formed by the conventional process, and determines the lateral width of the cavity; the thickness of the sacrificial layer structure 11 determines the sensitivity gain of the thermopile structure, that is, The thicker the thickness, the larger the gain, whereby the sensitivity of the temperature detector can be improved by modulating the thickness of the sacrificial layer structure 11. It should be noted that, considering the influence of the thermal noise Vn=(4KTR) ^1/2 of the resistance value R of the thermocouple in the temperature detector on the signal-to-noise ratio, the thickness has an extreme value, and the extreme value limits the stereoscopic The maximum sensitivity of the temperature detector, for example, the thickness of the sacrificial layer structure 11 may be 0.1 um - 100 um, and more specifically, may be, for example, 50 um.

Step S603: forming a first layer of thermopile material structure 12.

In this embodiment, the step S603 may include the following steps:

1) Depositing a first layer of thermopile material 12a.

Depositing a layer of thermopile material 12a over the formed sacrificial layer structure 11 to cover the entire sacrificial layer structure, as shown in FIG. 7D; and, the first layer of thermopile material 12a may have a larger Seebeck coefficient To increase the overall sensitivity of the temperature detector.

2) Forming a first layer of thermopile material structure 12.

A first layer of thermopile material pattern is formed by reticle lithography, and the pattern is etched to form a first layer of thermopile material structure 12. As shown in FIG. 7E, the first layer of thermopile material structure 12 is formed on an upper surface and a sidewall of the sacrificial layer structure 11, and the first layer of thermopile material structure 12 has a structure of the sacrificial layer a portion of the upper surface of the first recess 13 is exposed, and the first layer of thermopile material structure 12 further has a first extension 12b covering a portion of the bottom of the bottom of the sacrificial layer structure 11. The first dielectric layer 10.

As shown in FIG. 7E, in a specific embodiment, the first groove 13 may be located at a center of the top of the sacrificial layer structure 11, thereby simplifying the process.

Step S604: Forming a second dielectric layer structure 14.

In this embodiment, the step S604 can include the following steps:

1) Depositing a second dielectric layer 14a.

A second dielectric layer 14a is deposited to cover the first layer of thermopile material structure 12 and fill the first recess 13 as shown in Figure 7F. The second dielectric layer 14a is used for electrical insulation of the first layer of thermopile material structure 12 and the second layer of thermopile material structure described later.

2) Forming a second dielectric layer structure 14.

A second dielectric layer pattern is formed by reticle lithography, and the pattern is etched to form a second dielectric layer structure 14. As shown in FIG. 7G, the second dielectric layer structure 14 covers the first a surface of the layer thermopile material structure 12 and the exposed surface of the first dielectric layer 10, the second dielectric layer structure 14 having a second recess 14b, a third recess 15 and a fourth recess 16, wherein The second groove 14b exposes the first groove 13, the third groove 15 exposes a portion of the first extension portion 12b, and the fourth groove 16 is located at the first groove 13 A portion of the outer first layer of thermopile material structure 12 is exposed; and, in a particular embodiment, the fourth groove 16 can be located at the edge of the top center of the sacrificial layer structure 11. Thus, the third recess 15 and the fourth recess 16 respectively become hot junction recesses and cold junction recesses for the electrical connection of the first layer of thermopile material and the second layer of thermopile material in series.

Step S605: Forming a second layer of thermopile material structure 17.

In this embodiment, the step S605 can include the following steps:

1) Depositing a second layer of thermopile material 17a.

A second layer of thermopile material 17a is deposited to cover the second recess 14a-fourth recess 16 as shown in Fig. 7H.

2) Forming a second layer of thermopile material structure 17.

A second layer of thermopile material structure pattern is formed by reticle lithography, and the pattern is etched to form a second layer of thermopile material structure 17. As shown in FIG. 7I, the second layer of thermopile material structure 17 covers the second dielectric layer structure 14, and the second layer of thermopile material structure 17 passes through the fourth recess 16 and the first layer of thermoelectricity. The stack of material structures 12 are joined, and the second layer of thermopile material structure 17 has a fifth recess 17b and a second extension 17c, wherein the fifth recess 17b exposes the first recess 13 The second extension portion 17c is located on a portion of the second dielectric layer structure 14 covering the first dielectric layer 10. surface.

In the present embodiment, the second layer thermopile material structure 17 and the first layer thermopile material structure 12 together form a thermocouple pair of the thermopile, and a thermal junction to be described later can be formed at the fourth groove 16. A cold junction can be formed at the other end of the pair of thermocouples. Wherein, at the cold junction, the pair of thermocouples may be an open circuit, whereby a pair of thermocouple materials of a second layer of thermopile material structure 17 and a first layer of thermopile material structure 12 may be used. In addition, in this embodiment, the first layer thermopile material structure (12) may be adjacent at least two, and the second layer thermopile material structure (17) may also be adjacent at least two, and The second layer of thermopile material structure (17) is connected to the adjacent first layer of thermopile material structure (12) via the third groove (15) to form a series of thermocouple pairs, with respect to the series For the connection form of the thermocouple pair, reference can be made to FIG. 7L which will be described later.

In this embodiment, the second layer of thermopile material 17 can also be used to fabricate the electrodes of the thermopile for subsequent packaging of leads and testing.

Step S606: Forming a third dielectric layer structure 18.

In this embodiment, the step S606 may include the following steps:

1) Depositing a third dielectric layer 18a.

A third dielectric layer 18a is deposited to cover the entire thermopile device structure, as shown in Figure 7J.

2) Forming a third dielectric layer structure 18.

A third dielectric layer structure pattern is formed by reticle lithography, and the pattern is etched to form a third dielectric layer structure 18. As shown in FIG. 7K, the third dielectric layer structure 18 covers the second layer thermopile structure 17, and the third dielectric layer structure 18 has a sixth recess 18b exposing the first recess 13 And making a part of the second extension 17c The seventh recess 19 of the dew.

7L is a plan view corresponding to FIG. 7K, and FIG. 7K is a cross-sectional view of FIG. 7L along the BB direction. As shown in FIGS. 7L and 7K, the second layer thermopile structure 17 is divided into a heat junction portion 17d and a strip-like conduction. a portion 17e, and a cold junction portion 17f, below the second layer thermopile structure 17, a second dielectric layer structure 14 and a first layer thermopile structure 12, wherein the conductive portion 17e will be the second layer of the thermopile structure 17 The heat junction portion 17d is connected to the cold junction portion 17f of the adjacent second layer thermopile structure, and the cold junction portion 17f is connected to the first thermopile structure 12 located thereunder via the third groove 15, thereby forming a series connection The pair of thermocouples; and the second dielectric layer structure 14 and the third dielectric layer structure 18 are distributed over the sidewalls and the upper surface of the sacrificial layer structure 11 to form a three-dimensional support film. In FIGS. 7L and 7K, 23 shows a portion of the thermocouple pair at the top of the

sacrificial layer structure

11, and 24 shows a portion of the thermocouple pair on the side wall and the bottom outer side of the sacrificial layer structure 11.

In this embodiment, the third dielectric layer structure 18 can be used for the passivation layer and the protective layer of the temperature detector; and the seventh recess 19 can serve as an electrode exposure recess of the temperature detector for Subsequent package leads and tests.

In addition, in this embodiment, as shown in FIG. 7K, the lateral area of the sixth groove 18b is smaller than the lateral area of the first groove 13, so that a part of the first groove 13 is exposed, Thus, the third dielectric layer structure 18 covers the sidewall of the sixth recess 18b to passivate and protect the sidewall of the sixth recess 18b.

Step S607: Forming the infrared absorbing layer structure 20.

In this embodiment, the step S607 may include the following steps:

1) The infrared absorbing layer 20a is deposited.

A layer of infrared absorbing layer 20a is deposited to cover the entire structure, as shown in Fig. 7M.

2) Forming the infrared absorbing layer structure 20.

An infrared absorbing layer structure pattern is formed by reticle lithography, and the pattern is etched to form an infrared absorbing layer structure 20. As shown in FIG. 7N, the infrared absorbing layer covering the seventh groove 19 is removed to expose a portion of the second extending portion 17c; the formed infrared absorbing layer structure 20 fills the sixth groove 18b for absorption. Infrared radiation; and the infrared absorbing layer structure 20 has an eighth recess 21 exposing a portion of the upper surface of the sacrificial layer structure 11 for releasing the sacrificial layer structure 11, for example, the eighth recess 21 A center of the infrared absorbing layer structure 20 may be formed.

In this embodiment, the ratio of the lateral area of the eighth recess 21 to the lateral area of the infrared absorbing layer structure 20 is very small, so the absorption of the infrared radiation of the temperature detector is not affected. For example, the ratio may be 1:10000-1:1000000, more specifically, for example, it may be 1:160000.

In addition, in the embodiment, the infrared absorbing layer structure 20 can not only fill the sixth recess 18b, but also cover a portion of the upper surface of the third dielectric layer structure 18, for example, as shown in FIG. 7N. The infrared absorbing layer structure 20 can also cover a portion of the third dielectric layer structure 18 corresponding to the fourth recess 16 , that is, a position corresponding to the thermal junction of the thermocouple pair, whereby the infrared absorbing layer structure 20 absorbs The heat can be quickly conducted to the hot junction, increasing the response speed of the stereoscopic temperature detector.

Step S608: removing the sacrificial layer structure 11 via the eighth recess 21 to form a cavity 22, as shown in FIG. 7O.

In this embodiment, the material of the sacrificial layer structure 11 may be a semiconductor fabrication worker. A sacrificial layer material commonly used in the art, such as one or more of materials such as polyimide, amorphous silicon, polycrystalline silicon, silicon oxide, and photoresist. In addition, the method for removing the sacrificial layer used in the step S608 is different, and the specific method may refer to the prior art, and details are not described in this embodiment.

In this embodiment, the material of the infrared absorbing layer may be titanium (Ti), titanium nitride (TiN), tantalum (Ta), tantalum nitride (TaN), gold black (black black), silicon black (Silicon black). And one or more of the dielectric layer composite film and the like.

In this embodiment, the first layer thermopile material structure and the second layer thermopile material structure may be doped polysilicon, bismuth (Sb) and its compound, bismuth (Bi) and its compound, and titanium (Ti, respectively). And a compound thereof, one of tantalum (Ta) and a compound thereof, aluminum (Al), and gold (Au); and the first layer of thermopile material structure and the second layer of thermopile material structure There are different Seebeck coefficients, whereby both can form a thermocouple pair for temperature detection.

According to the above description, compared with the conventional double-sided etching of the back surface groove, the manufacturing method of the present application produces a cavity by sacrificial layer spin coating, curing, photolithography etching, release, etc., and the alignment precision is far. It is higher than the double-sided process; compared with the conventional front etching technology, the manufacturing method of the present application can precisely control the etching width through the photoresist mask, and there is no over-etching phenomenon; therefore, the process of the manufacturing method of the present application High stability and guaranteed device performance.

Hereinafter, a specific embodiment of the packaging method of the present embodiment will be described in detail with reference to specific examples and FIG. 7. In the specific embodiment, the sacrificial layer structure 11 is made of polyimide (PI), the first dielectric layer 10 and the first The three dielectric layer structure 18 is made of silicon nitride (Si ₃ N ₄ ), the second dielectric layer structure 14 is made of silicon oxide (SiO ₂ ), the infrared absorption layer structure 20 is made of gold black, and the first layer of thermopile material structure is used. 12 is made of boron-doped polysilicon (PolySi: B), the second layer of thermopile material structure 17 is made of aluminum (Al), and the substrate 9 may be a silicon wafer.

Specific steps are as follows:

1) A silicon nitride film is deposited on the silicon wafer 9 by LPCVD or PECVD as the first dielectric layer 10 of the temperature detector.

2) Epoxy, silicone, high temperature curing of a polyimide sacrificial layer 11a on the silicon nitride 10; photoresist pattern coated on the sacrificial layer 11a by reticle lithography, etching by RIE or IBE This pattern forms a sacrificial layer structure 11.

3) depositing a polysilicon film by LPCVD or PECVD on the basis of the formed sacrificial layer structure 11, and doping a certain concentration of boron to form a boron-doped polysilicon film, that is, the first layer of thermopile material 12a, It covers the entire sacrificial layer structure 11. The photoresist pattern on the first layer of thermopile material 12a is photolithographically patterned by reticle, and the pattern is etched by RIE or IBE to form a first layer of thermopile material structure 12. The structure exposes a groove pattern on the upper surface of the sacrificial layer structure 11 as the first groove 13.

4) Continue to deposit a silicon oxide film 14a by LPCVD or PECVD to cover the boron doped polysilicon film structure 12 and fill the exposed first recess 13. The photoresist pattern on the silicon oxide film 14a is photolithographically coated by a reticle, and the pattern is etched by RIE or IBE to form a second dielectric layer structure 14. In addition to exposing the first recess 13, the structure also forms a recess 15 and a recess 16 at its junction with the first layer of thermopile material.

5) depositing a layer of aluminum film 17a by evaporation or sputtering to cover the above Three

grooves

13, 15, 16. The photoresist pattern on the aluminum thin film is photolithographically coated by a reticle, and the pattern is etched by RIE or IBE or wet etching to form a first layer of thermopile material structure 17, which is combined with a boron doped polysilicon film. 12 together form a pair of thermocouples and continue to expose the first recess 13.

6) A silicon nitride film 18a is deposited by LPCVD or PECVD to cover the entire thermopile device structure. The dielectric layer 18a is used for the passivation layer and the protective layer of the temperature detector. The photoresist pattern on the silicon nitride film 18a is photolithographically coated by a reticle, and the pattern is etched by RIE or IBE to form a third dielectric layer structure 18. The structure continues to expose the first recess 13 at the top. The groove 19 is exposed at the bottom.

7) A gold film 20a is deposited by evaporation under a low pressure atmosphere of nitrogen, for example, 100-300 Pa. The gold film is deposited in a nitrogen atmosphere and is black under macroscopic conditions for absorbing infrared radiation. The gold black film 20 covers the groove 13 and the groove 19. The photoresist pattern on the gold black film 20a is photolithographically coated by a reticle, and the pattern is etched by wet or RIE or IBE to expose the electrode, and an infrared absorbing layer 20 is formed on top of the sacrificial layer 11. . Further, a minute groove 21 is formed in the center of the infrared absorbing layer for the release of the sacrificial layer structure 11.

8) The sacrificial layer structure 11 is released by radio frequency or microwave extraction by oxygen plasma ashing to form the cavity 22.

9) Glue protection, cutting wafer, acetone solution to remove photoresist, stereoscopic temperature detector is completed.

Example 2

Embodiment 2 of the present application provides a stereoscopic temperature detector. 3 is a schematic top plan view of the three-dimensional temperature detector, FIG. 4 is a longitudinal sectional structural view taken along line A-A of FIG. 3, and FIG. 5 is a side view structural view of the three-dimensional temperature detector. As shown in Figure 3-5, the stereoscopic temperature detector includes:

Substrate (9);

a first dielectric layer 10 on the surface of the substrate (9);

A first layer of thermopile material structure 12, a second dielectric layer structure 14, a second layer of thermopile material structure 17, and a third dielectric layer structure 18 stacked in this order from the bottom to the top of the first dielectric layer 10 And the first dielectric layer 10, the second dielectric layer structure 14, and the third dielectric layer structure 18 enclose a cavity 22;

The top of the cavity has a sixth recess 18b and an infrared absorbing layer structure 20 filling the sixth recess 18b, the infrared absorbing layer structure 20 having an eighth recess 21 for communicating the cavity 22 with the outside. ;

The second dielectric layer structure 14 has a third recess 15 and a fourth recess 16 at the top of the cavity 22 and outside the sixth recess 18b. The third groove 15 is located outside the bottom of the cavity 22, and the second layer of thermopile material structure 17 is connected to the first layer of thermopile material structure 12 by the fourth groove 16.

In the present embodiment, the first dielectric layer 10 is responsible for the electrical insulation of the thermopile from the substrate 9, and the second dielectric layer structure 14 is responsible for the electrical insulation of the first layer of thermopile material structure 12 and the second layer of thermopile material structure 17, The third dielectric layer structure 18 is responsible for the passivation and protection of the thermopile structure, and the infrared absorbing layer structure 20 and the first layer of the thermopile material structure 12 and the second layer of thermopile material structure 17 are electrically insulated; and the second dielectric layer structure 14 and the third dielectric layer structure 18 are distributed over the sidewalls and the upper surface of the entire cavity to form a three-dimensional support layer; the first layer of thermopile material The structure 12 and the second layer of thermopile material structure 17 constitute a thermal junction and a cold junction of the thermopile for generating an electromotive force difference caused by the temperature difference; the infrared absorption layer structure 20 is responsible for absorption from the outside through the optical system to the surface of the thermopile detector The infrared radiation generates heat that is conducted to the thermopile; the cavity 22 is responsible for forming the thermopile insulation structure to reduce the amount of heat generated by the body effect.

In this embodiment, the first layer of thermopile material structure 12 may be adjacent at least two, and the second layer of thermopile material structure 17 may be adjacent at least two, wherein the second layer A thermopile material structure 17 is coupled to the adjacent first layer of thermopile material structure 12 via the third recess 15 to form a series of thermocouple pairs.

For a detailed description of the components of the stereoscopic temperature detector in Embodiment 2, reference may be made to Embodiment 1, and details are not described herein again.

For a thermocouple pair composed of a thermocouple double material, it is generally elongated and has a certain thickness, and its thermal conductivity expression is G=λS/L, where λ is thermal conductivity and S is cross-sectional area. L is the length of the object. Therefore, the thermal conductivity G _tc of the thermocouple pair is G _tc =N(λ ₁ S ₁ /L ₁ +λ ₂ S ₂ /L ₂ ), and it can be seen that the material, the thermocouple pair logarithm, and the material cross-sectional area In certain cases, increasing the length of the thermocouple pair can reduce thermal conductivity.

In addition, on the one hand, compared with the cantilever beam and the suspension structure, the closed membrane structure has an additional thermal conductivity, that is, the thermal conductivity of the support layer. Different shapes of support layers have different thermal conductivity expressions. In the present application, a square infrared absorption region structure may be employed, wherein a and b are respectively the distance from the center of the sealing film to the hot junction region and the cold junction region, λ _mem is the thermal conductivity of the support layer, and t _mem is the thickness thereof. Then there is G _men =8λ _mem *t _mem /Ln(b/a). For a stereo-type thermopile detector, the distance from the center of the closed film to the hot junction is the same as that of the conventional method. The distance to the cold junction region is increased to b + t _PI due to its three-dimensional structure, where t _PI refers to the thickness of the sacrificial layer. It can be seen from the above formula that the thermal conductivity value of the sealing film decreases as the length of the sealing film becomes longer.

On the other hand, the sensitivity or response rate Rv is an important indicator for evaluating the performance of the temperature detector, which is defined as the ratio of the output voltage ΔV to the incident radiant power P, in units of V/W, ie Rv = ΔV/P. ΔV is the potential difference generated by the Seebeck effect. The incident radiant power P can be expressed as P=G _total *ΔT/(η*t). The two equations can be combined to obtain the relationship between the response rate and the thermal conductivity. Rv=η*t*N *(α1-α2)/G _total . As the thermal conductivity decreases, the temperature difference generated by the thermopile increases, and the sensitivity or response rate of the detector increases accordingly.

It can be seen from the above analysis that the three-dimensional temperature detector of the present application increases the length of the support layer by forming a three-dimensional cavity, and the length of the film and the thermopile under the same size conditions as compared with the conventional thermopile. The length of the dual material is increased, which in turn reduces the total thermal conductivity of the thermopile device and increases the sensitivity of the temperature detector to detect temperature.

The present invention has been described in connection with the specific embodiments thereof, but it is to be understood that the description is intended to be illustrative and not restrictive. Various modifications and alterations of the present application are possible in light of the spirit and scope of the invention, which are also within the scope of the present application.

Claims

A method of manufacturing a stereoscopic temperature detector, the method comprising:

Depositing a first dielectric layer (10) on the substrate (9);

Forming a sacrificial layer structure (11) on the first dielectric layer (10);

Forming a first layer of thermopile material structure (12) on an upper surface and a sidewall of the sacrificial layer structure (11), the first layer of thermopile material structure (12) having an upper surface of the sacrificial layer structure a portion of the exposed first recess (13), and the first layer of thermopile material structure (12) further has a first extension (12b), the first extension (12b) covering the sacrificial layer structure (11) a portion of the first dielectric layer (10) on the outside of the bottom;

Forming a second dielectric layer structure (14) to cover the surface of the first layer of thermopile material structure (12) and the exposed surface of the first dielectric layer (10), the second dielectric layer structure (14) having a second groove (14b), a third groove (15) and a fourth groove (16), wherein the second groove (14b) exposes the first groove (13), the third a recess (15) exposing a portion of the first extension (12b), the fourth recess (16) aligning the first layer of thermopile material structure outside the first recess (13) a part of (12) is exposed;

Forming a second layer of thermopile material structure (17) to cover the second dielectric layer structure (14), the second layer of thermopile material structure (17) passing through the fourth groove (16) and the first A layer of thermopile material structure (12) is connected, the second layer of thermopile material structure (17) having a fifth groove (17b) and a second extension (17c), wherein the fifth groove (17b) The first recess (13) is exposed, and the second extension (17c) is located on a surface of the second dielectric layer structure (14) covering a portion of the first dielectric layer (10);

Forming a third dielectric layer structure (18) to cover the second layer thermopile structure (17), the third dielectric layer structure (18) having a sixth recess exposing the first recess (13) (18b), and a seventh recess (19) exposing a portion of the second extension (17c);

Forming an infrared absorbing layer structure (20) filling the sixth recess (18b), the infrared absorbing layer structure (20) having an eighth recess exposing a portion of an upper surface of the sacrificial layer structure (11) (twenty one);

The sacrificial layer structure is removed via the eighth recess (21) to form a cavity (22).
The method of manufacturing a three-dimensional temperature probe according to claim 1, wherein

The first layer of thermopile material structure (12) has adjacent at least two, the second layer of thermopile material structure (17) has adjacent at least two, and the second layer of thermopile material The structure (17) is coupled to the adjacent first layer of thermopile material structures (12) via the third recess (15) to form a series of thermocouple pairs.
The method of manufacturing a three-dimensional temperature probe according to claim 1, wherein

The material of the infrared absorbing layer is titanium (Ti), titanium nitride (TiN), tantalum (Ta), tantalum nitride (TaN), gold black (black black), silicon black (silica black) and dielectric layer composite film. One or more of them.
The method of manufacturing a three-dimensional temperature probe according to claim 1, wherein

The first layer thermopile material structure and the second layer thermopile material structure are doped polysilicon, bismuth (Sb) and its compound, bismuth (Bi) and its compound, titanium (Ti) and its compound, bismuth, respectively. (Ta) and one of its compounds, aluminum (Al) and gold (Au);

And, the first layer of thermopile material structure and the second layer of thermopile material structure have different Seebeck coefficients.
The method of manufacturing a three-dimensional temperature probe according to claim 1, wherein

The ratio of the lateral area of the eighth groove (21) to the lateral area of the infrared absorbing layer structure (20) is 1:10000-1:1000000.
The method of manufacturing a three-dimensional temperature probe according to claim 1, wherein

The sacrificial layer structure (11) has a thickness of 0.1 to 100 um.
The method of manufacturing a three-dimensional temperature probe according to claim 1, wherein

The lateral area of the sixth groove (18b) is smaller than the lateral area of the first groove (13).
A stereo temperature detector comprising:

Substrate (9);

a first dielectric layer (10) on a surface of the substrate (9);

a first layer of thermopile material structure (12), a second dielectric layer structure (14), and a second layer of thermopile material structure (17) stacked on the surface of the first dielectric layer (10) in this order from bottom to top And a third dielectric layer structure (18), and the first dielectric layer (10), the second dielectric layer structure (14), and the third dielectric layer structure (18) enclose a cavity ( twenty two);

The top of the cavity has a sixth recess (18b) and an infrared absorbing layer structure (20) filling the sixth recess (18b), the infrared absorbing layer structure (20) having the cavity (22) An eighth groove (21) communicating with the outside;

The second dielectric layer structure (14) has a third recess (15) and a fourth recess (16), the fourth recess (16) being located at the top of the cavity (22) and located at the The outer side of the sixth recess (18b), the third recess (15) is located outside the bottom of the cavity (22), and the second layer of thermopile material structure (17) passes through the A four groove (16) is coupled to the first layer of thermopile material structure (12).
The stereoscopic temperature probe according to claim 8, wherein

The first layer of thermopile material structure (12) has adjacent at least two, and the second layer of thermopile material structure (17) has adjacent at least two, wherein the second layer of thermoelectricity Heap material structure (17) and adjacent first layer thermopile material structure (12) connected via the third groove (15) to form a pair of thermocouples in series.
The stereoscopic temperature probe according to claim 8, wherein

The first layer thermopile material structure (12) and the second layer thermopile material structure (17) are doped polysilicon, bismuth (Sb) and its compound, bismuth (Bi) and its compound, and titanium (Ti), respectively. And one of its compounds, ruthenium (Ta) and its compounds, aluminum (Al) and gold (Au);

And, the first layer of thermopile material structure and the second layer of thermopile material structure have different Seebeck coefficients.