CN216426756U - MEMS infrared light source - Google Patents

Abstract

The utility model provides an MEMS infrared light source, and belongs to the technical field of infrared light sources. The technical scheme is as follows: an MEMS infrared light source comprises a heating layer, wherein the heating layer comprises a heating source made of a Pt metal film as a conductor and connecting electrodes arranged at two ends of the heating source; the heating source comprises a plurality of groups of resistor structures which are arranged in parallel and connected in series end to end, and the connecting ends of the adjacent resistor structures are integrally connected; each resistance structure comprises at least two strip conductors which are arranged in parallel. The utility model has the beneficial effects that: the adopted heating source structure can not only improve the heating efficiency and provide enough heat for the light source, but also effectively heat the conductor and reduce the risk of conductor fracture caused by different thermal deformation amounts of different areas; the stability of the infrared light source is improved, and the service life is prolonged; the preparation process is simple, the production cost is low, and the method is suitable for mass production.

Description

MEMS infrared light source

Technical Field

The utility model relates to the technical field of infrared light sources, in particular to an MEMS infrared light source.

Background

The gas sensor based on the infrared optical principle is a gas sensing device which selects absorption characteristics based on near infrared spectra of different gas molecules, utilizes the relation between gas concentration and absorption intensity to identify gas components and determine the concentration of the gas components, and has the advantages of wide detection range, large detection range, strong anti-interference capability and the like.

The current infrared light source is more and more widely applied in the field of integration, for example, a non-dispersive infrared (NDIR) gas sensor module, the traditional infrared light source display cannot adapt to the field of integration, the realization of the infrared light source in the field of semiconductors is solved by combining an MEMS (micro-electromechanical systems) process, and a blackbody radiation layer is heated by a heating electrode to emit broad-spectrum thermal radiation infrared light; generally, the heating conductor is made of a metal film, but when the whole metal film is adopted, the structure is relatively stable, but the heating efficiency is poor; the metal wire heating conductor is manufactured through a patterning process, so that the heating efficiency is improved, but when the metal wire generates heat, the heat conduction efficiency of the metal wire is reduced, so that the heat deformation amount of the metal wire at different positions is different, and the metal wire is easy to break due to the generation of internal stress.

SUMMERY OF THE UTILITY MODEL

In view of the above problems in the prior art, an object of the present invention is to provide an MEMS infrared light source, in which a Pt metal film is set as a heating source on a supporting layer through a patterning process, and an overall structure of the heating source is composed of a plurality of sets of parallel and series resistor structures, so that not only is heating efficiency improved, but also the risk of conductor fracture caused by different thermal deformation during heating can be reduced, and structural stability of the heating source is ensured.

The utility model is realized by the following technical scheme: an MEMS infrared light source comprises a heating layer, wherein the heating layer comprises a heating source made of a Pt metal film as a conductor and connecting electrodes arranged at two ends of the heating source; the heating source comprises a plurality of groups of resistor structures which are arranged in parallel and connected in series end to end, and the connecting ends of the adjacent resistor structures are integrally connected; each resistance structure comprises at least two strip conductors which are arranged in parallel. The Pt metal film is made into a heating source through graphic processes such as plate making, photoetching, sputtering or deposition, the integral structure can improve the thermal stability of the structure in an integrated mode, the middle part of the Pt metal film is provided with the strip conductor structures which are arranged in parallel, the heating efficiency can be improved, and the heating effect is good.

The heating source is in the heating process, and the temperature distribution of each position is different, and each region is different by the internal stress that the temperature produced, through with the regional processing of middle part of heating source becomes a plurality of bar conductors that parallel, but wholly still is the structural setting of integration, reduces because the internal stress leads to the cracked risk of conductor.

Considering the processing precision of a photoetching machine and the thermal stress and the thermal expansion coefficient of materials, further, the gap between the adjacent strip conductors is not less than 20 μm.

Further, the connection electrode is made of a Pt metal film or an Au metal film. The connection electrode can be connected with an external circuit as a welding electrode and is manufactured through a patterning process.

In order to reduce the thermal contact resistance value of different metal film materials caused by the fact that the contact surface gap is enlarged in the heating process, the connection position of the connection electrode and the resistor structure is ensured to have a larger width, and further the connection width of the connection electrode and the resistor structure is not less than 200 μm.

In order to improve the emissivity of the heat source, the black body film is arranged on the heating layer and can cover the heating source, and the connecting electrode is arranged on the periphery of the black body film. The black body film is made of a gold black film, a platinum black film or a carbon black film and is deposited on the heating layer to serve as a black body radiation layer.

In combination with the MEMS process, the MEMS heat-generating device further comprises a substrate layer, wherein a supporting layer is arranged on the substrate layer, a titanium adhesion layer is arranged on the supporting layer, and the heating layer is arranged on the titanium adhesion layer through a patterning process.

Further, a cavity is formed in the middle of the substrate layer in an etching mode, and the coverage surface of the cavity is larger than that of the heating source. The substrate layer is processed into a cavity through a deep groove process, so that heat conduction is blocked, heat loss is reduced, and power consumption of the sensor is reduced.

Furthermore, the supporting layer is composed of two layers of compounds, and the upper layer of silicon nitride plays a supporting role; the lower layer of silicon oxide plays a role in heat insulation;

further, the substrate layer is double-polished monocrystalline silicon.

Furthermore, the supporting layer is prepared by methods such as LPCVD deposition and the like, and the thickness is 400-600 nm.

The utility model has the beneficial effects that: the heating source structure adopted by the utility model can not only improve the heating efficiency and provide enough heat for the light source, but also effectively heat the conductor and reduce the risk of conductor fracture caused by different thermal deformation amounts of different areas; the stability of the infrared light source is improved, and the service life is prolonged; the preparation process is simple, the production cost is low, and the method is suitable for mass production.

Drawings

Fig. 1 is a schematic view of the overall structure of the heating source.

Fig. 2 is a schematic structural diagram of an infrared light source.

Fig. 3 is a schematic view of the structure of the substrate layer.

FIG. 4 is a graph showing the temperature profile of the heating source at 3V.

FIG. 5 is a first simulation test chart of deformation of a heating source.

FIG. 6 is a second simulation testing chart of deformation of the heating source.

Fig. 7 is a third simulation test chart of deformation of the heating source.

Wherein the reference numerals are: 1. a substrate layer; 11. a cavity; 2. a support layer; 21. Silicon nitride; 22. silicon oxide; 3. a titanium adhesion layer; 4. a heat generating layer; 41. a heating source; 411. a strip conductor; 42. connecting the electrodes; 5. black body film.

Detailed Description

In order to clearly illustrate the technical features of the present solution, the present solution is explained below by way of specific embodiments.

Referring to fig. 1-4, the utility model is realized by the following technical scheme: an MEMS infrared light source comprises a heating layer 4, wherein the heating layer 4 comprises a heating source 41 made of a Pt metal film as a conductor and connecting electrodes 42 arranged at two ends of the heating source 41; the heating source 41 comprises a plurality of groups of resistor structures which are arranged in parallel and connected end to end in series, and the connecting ends of adjacent resistor structures are integrally connected; each resistor structure comprises at least two strip conductors 411 arranged in parallel. The Pt metal film is made into the heating source 41 through graphic processes such as plate making, photoetching, sputtering or deposition, the integral structure can improve the thermal stability of the structure in an integrated mode, the middle part of the structure is provided with the strip conductor structures which are arranged in parallel, the heating efficiency can be improved, and the heating effect is good.

As shown in fig. 4, in the heating source 41, the temperature distribution of each part is different in the heating process, the internal stress generated by the temperature in each region of the whole conductor is different, and the central region of the heating source 41 is processed into a plurality of parallel strip conductors, but the whole is still arranged in an integrated structure, so that the risk of conductor fracture caused by the internal stress can be reduced.

As shown in fig. 5-7, the deformation simulation test is performed when the heating source is set to different patterns, the test conditions are that the heating layer reaches the same temperature, the simulation geometry structure is different except for the electrode patterns, and the rest is the same; the test results were as follows: the maximum deformation in FIG. 5 is 109 nm; the maximum deformation in FIG. 6 is 173nm, and since the deformation is too large, it directly results in no void in the middle; the maximum deformation in FIG. 7 is 148 nm; it is apparent that the pattern used for the heating source 41 in the present invention is more effective in coping with the deformation generated during the heat generation.

The gap between the adjacent strip conductors 411 is not less than 20 μm in consideration of the processing accuracy of the photolithography machine and the thermal stress and thermal expansion coefficient of the material.

The connection electrode 42 is made of a Pt metal film or an Au metal film. The connection electrode 42 as a welding electrode can be connected to an external circuit, and is formed by a patterning process.

In order to reduce the thermal contact resistance value of different metal film materials due to the fact that the contact surface gap is enlarged in the heating process, the connection position of the connection electrode 42 and the resistor structure is ensured to have a larger width, and the connection width of the connection electrode 42 and the resistor structure is not smaller than 200 μm.

In order to improve the emissivity of the heat source 41, the black body film 5 is disposed on the heat generating layer 4 and can cover the heat source 41, and the connection electrode 42 is disposed on the periphery of the black body film 5. The black body film 5 is made of a gold black film, a platinum black film or a carbon black film and is deposited on the heating layer 4 to be used as a black body radiation layer.

The MEMS technology is combined, the MEMS technology further comprises a substrate layer 1, a supporting layer 2 is arranged on the substrate layer 1, a titanium adhesion layer 3 is arranged on the supporting layer 2, and a heating layer 4 is arranged on the titanium adhesion layer 3 through a patterning technology. Removing the residual photoresist on the surface of the supporting layer 2 by using a photoresist machine, etching for about 3 minutes, sputtering a layer of metal titanium with the thickness of 50nm as a titanium adhesion layer 3, sputtering metal Pt on the titanium adhesion layer 3 as a heating layer 4, wherein the titanium adhesion layer 3 plays a role in increasing the adhesion between the supporting layer 2 and the heating layer 4.

The middle part of the substrate layer 1 is etched to form a cavity 11, and the covering surface of the cavity 11 is larger than that of the heating layer 41.

The substrate layer 1 is processed into a cavity 11 through a deep groove process, so that heat conduction is blocked, heat loss is reduced, and power consumption of the sensor is reduced.

The supporting layer 2 is composed of two layers of composites, the supporting layer is composed of two layers of composites, and the upper layer of silicon nitride 21 plays a supporting role; the underlying silicon oxide 22 serves as thermal insulation.

The substrate layer 1 is double-polished monocrystalline silicon.

The support layer 2 is prepared by LPCVD deposition and the like, and the thickness is 400-600 nm.

The MEMS infrared light source manufactured by the semiconductor manufacturing process has the advantages of high integration level, stable heating, high heating efficiency and simple manufacturing process, and is suitable for batch production.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings, which are merely for convenience in describing the utility model and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be construed as limiting the utility model.

In the description of the utility model, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted", "connected" and "disposed" are to be construed broadly, e.g. as being fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the creation of the present invention can be understood by those of ordinary skill in the art through specific situations.

The technical features of the present invention which are not described in the above embodiments may be implemented by or using the prior art, and are not described herein again, of course, the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and variations, modifications, additions or substitutions which may be made by those skilled in the art within the spirit and scope of the present invention should also fall within the protection scope of the present invention.

Claims (8)

1. An MEMS infrared light source is characterized by comprising a heating layer, wherein the heating layer comprises a heating source and connecting electrodes, the heating source is made of a Pt metal film serving as a conductor, and the connecting electrodes are arranged at two ends of the heating source; the heating source comprises a plurality of groups of resistor structures which are arranged in parallel and connected in series end to end, and the connecting ends of the adjacent resistor structures are integrally connected; each resistance structure comprises at least two strip conductors which are arranged in parallel.

2. The MEMS infrared light source of claim 1 wherein a gap between adjacent ones of the strip conductors is not less than 20 μ ι η.

3. The MEMS infrared light source as claimed in claim 1, wherein the connection electrode is made of a Pt metal film or an Au metal film.

4. The MEMS infrared light source of claim 3 wherein the connection width of the connection electrode to the resistive structure is not less than 200 μ ι η.

5. The MEMS infrared light source as claimed in claim 1, further comprising a black body film disposed on the heat generating layer and capable of covering the heat source, wherein the connection electrode is disposed at a periphery of the black body film.

6. The MEMS infrared light source of claim 5, further comprising a substrate layer, wherein the substrate layer is provided with a support layer, the support layer is provided with a titanium adhesion layer, and the heating layer is arranged on the titanium adhesion layer through a patterning process.

7. The MEMS infrared light source of claim 6 wherein the middle portion of the substrate layer is etched to form a cavity, the cavity having a footprint larger than the heating source.

8. The MEMS infrared light source of claim 6 wherein the support layer is a two layer composite, the upper layer being silicon nitride and the lower layer being silicon oxide.

Images