CN102931201A - Energy-gathering micro-mirror array based on infrared focal plane array and manufacturing method thereof - Google Patents

Abstract

The present invention provides an infrared focal plane array-based energy-concentrating micromirror array, which includes a plurality of energy-concentrating micromirror units located on the base, and the energy-concentrating micromirror unit includes a through hole and a microlens. The port is not smaller than the lower port, and the side wall of the through hole is between the upper port and the lower port; the microlens covers the upper port of the through hole; wherein the upper port of the through hole in at least one energy-gathering micromirror unit is larger than the lower port The port also includes a micro-mirror covering the inner sidewall of the through hole, and the micro-mirror reflects the light incident on the micro-mirror through the micro-lens to the lower port of the through-hole; The lower port of the middle through hole corresponds to the photosensitive absorption region of the infrared focal plane array. Correspondingly, the present invention also provides a method for manufacturing an energy-concentrating micromirror array based on an infrared focal plane array. The invention can reduce the waste of incident light and improve the filling factor of the infrared focal plane array integrated with the energy-concentrating micromirror array.

Description

Energy-concentrating micromirror array based on infrared focal plane array and its manufacturing method

technical field

The invention relates to the field of infrared imaging energy gathering, in particular to an energy gathering micromirror array based on an infrared focal plane array and a manufacturing method thereof.

Background technique

Infrared imaging technology has a very wide range of applications in both civilian and military fields, and has always been one of the irreplaceable practical technologies in the military field, such as for long-distance warning systems and weapon targeting systems, individual portable night vision devices, helmet night vision devices And infrared search and tracking system, etc., and the design of IRFPA (infrared focal plane array, infrared focal plane array) is the most core technology in infrared imaging system. The photosensitive element array is arranged on the focal plane of the IRFPA, and the infrared rays emitted from infinity are imaged on these photosensitive elements on the infrared focal plane through the optical system, and the detector including the IRFPA converts the received light signal into an electrical signal and integrates it. Amplify, sample and hold, through the output buffer and multiplex transmission system, and finally sent to the monitoring system to form an image.

The photosensitive absorption region range of the photosensitive element of the IRFPA that has been developed at present is relatively small, see Fig. 1, is a schematic diagram of a photosensitive element of IRFPA among the figure, the photosensitive absorption region 102 of photosensitive element 101 only accounts for about 40% of photosensitive element area, incident About 40% of the light 103 is absorbed by the photosensitive element, and about 60% of the incident light cannot be used by the photosensitive element. This part of wasted light is called "dead light". The filling factor of the infrared focal plane array is the ratio of the light effectively utilized by the infrared focal plane array to the incident light, and the existing filling factor of the infrared focal plane array is about 40%. With the further research of the infrared focal plane array, the area ratio of the photosensitive absorption region in the focal plane will become smaller and smaller, so how to collect the "dead light" that cannot be used and improve the fill factor of the IRFPA is an urgent problem to be solved. . The monolithic integration of microlens array and IRFPA is the best way to solve this problem. Monolithic forward integration of energy-concentrating microlenses on infrared detectors and infrared focal plane arrays is the development trend of miniaturization of infrared detectors and infrared focal plane array devices. Figure 2 is a schematic diagram of the principle of integrating energy-concentrating microlenses in the forward direction of the photosensitive element. Absorption zone 102. The integration of energy-gathering microlenses can gather the "dead light" that cannot be utilized to the photosensitive absorption area, and theoretically can make the fill factor of the photosensitive element reach 100%.

In the development of the current energy-concentrating microlens array, the "photoresist thermal melting-etching transfer" method is used to fabricate the energy-concentrating microlens array. array, and then transfer the photoresist pattern to the silicon substrate by etching with argon ions, etc., and finally obtain a microlens array made of silicon. As shown in Figure 3, the energy-concentrating microlens array includes multiple microlens units 201 (shown in the dotted line box), the lenses in such an energy-concentrating micromirror unit include a convex lens 202 that can converge light in the middle and a planar lens 203 that cannot converge incident light at the edge. The problem in the prior art is that the microlens unit manufactured by this method has a plane lens whose edge cannot gather the incident light, and the light incident on the plane lens of the microlens unit cannot be refracted to the photosensitive absorption area of the photosensitive element and be absorbed. Waste, when the microlens array obtained by this method is integrated with other devices such as CCD (Charge-coupled Device, charge-coupled device), FPA (focal plane array, focal plane array) and other detectors, it cannot fully gather the incident light energy to the device. In the photosensitive absorption region, the maximum filling factor is 78.5%, which is far from the theoretical maximum filling factor of 100%.

Contents of the invention

The invention provides an energy-concentrating micromirror array based on an infrared focal plane array, which can improve the filling factor of the infrared focal plane array integrated with the microlens array in the forward direction.

In order to solve the above problems, the present invention provides a kind of energy-concentrating micromirror array based on infrared focal plane array, including a plurality of energy-concentrating micromirror units located at the base,

The energy-concentrating micromirror unit includes a through hole and a microlens, wherein,

The upper port of the through hole is not smaller than the lower port, and the side wall of the through hole is between the upper port and the lower port;

The microlens covers the upper port of the through hole;

Wherein, at least one energy-concentrating micromirror unit includes a microreflector,

The micro-mirror covers the side wall of the through hole, and the micro-mirror reflects the light incident on the micro-mirror through the micro-lens to the lower port of the through-hole;

The upper port of the through hole of the energy-concentrating micromirror unit comprising the microreflector is larger than the lower port;

The lower port of the through hole in the energy-concentrating micromirror unit corresponds to the photosensitive absorption area of the infrared focal plane array.

Preferably, the upper ports of the through holes in the plurality of energy-concentrating micromirror units are closely arranged to form a plane without gaps.

Preferably, the upper port of the through hole in the energy-concentrating micromirror unit is parallelogram, square or regular hexagon.

Preferably, the energy-concentrating micro-mirror units all include micro-mirrors.

Wherein, the lower port and the upper port of the through hole in the energy-concentrating micromirror unit have the same shape, and the side walls of the through hole include multiple planes.

Wherein, the lower port of the through hole in the energy-concentrating micromirror unit is circular, and the inner sidewall of the through hole is a curved surface.

Wherein, the microlenses in the energy concentrating micromirror unit include microlenses in the middle that can converge incident light and microlenses that cannot converge incident light at the edge.

Wherein, the energy-concentrating micromirror unit also includes a second through hole and a second microlens located in the substrate in addition to the first through hole and the first microlens, wherein,

The upper port of the second through hole shares a side with the upper port of the first through hole;

The second microlens covers the upper port of the second through hole, and refracts all the light incident on the second microlens to the lower port of the second through hole;

The lower port of the second through hole corresponds to the photosensitive absorption area of the infrared focal plane array.

Wherein, in the energy-concentrating micromirror unit, except the first micromirror covered on the inner wall of the through hole, the second micromirror whose surface is a reflective surface is also included between the upper port of the through hole and the microlens. The two micro mirrors are perpendicular to the base, the upper port and the lower port have the same shape, and the lower port coincides with the upper port of the through hole.

Preferably, the material of the micro-mirror in the energy-concentrating micro-mirror unit is aluminum, copper, iron or nickel alloy.

Preferably, the microlenses in the energy concentrating micromirror unit are refractive lenses or diffractive lenses.

Preferably, the microlenses in the energy concentrating micromirror unit are convex lenses.

Preferably, the material of the convex lens in the energy-concentrating micromirror unit is silicon.

Preferably, the microlens in the energy concentrating micromirror unit is a shell spherical lens or a shell planar lens.

Preferably, the microlens material in the energy-focusing micromirror unit is polycarbonate PC or polystyrene PS.

Correspondingly, a method for manufacturing an infrared focal plane array-based energy-concentrating micromirror array is also provided, including:

A plurality of through holes with upper ports not smaller than the lower ports are etched on the substrate, and the lower ports of the through holes correspond to the photosensitive absorption regions of the IRFPA;

Making a micro-mirror and a micro-mirror protective layer on the side wall of the through hole where the upper port is larger than the lower port;

filling the microlens sacrificial material in the through hole of the substrate;

Fabricating microlenses on via holes filled with microlens sacrificial material;

The microlens sacrificial material and micromirror protective layer inside the vias are released.

Wherein, the manufacturing method of the described energy-concentrating micromirror array based on the infrared focal plane array also includes:

The base made of the micro-reflector and the micro-lens is glued to the infrared focal plane array by using optical glue, so that the lower port of the through hole corresponds to the photosensitive absorption area of the infrared focal plane.

Wherein, the manufacturing method of the described energy-concentrating micromirror array based on the infrared focal plane array includes the substrate manufacturing step:

The substrate is the infrared focal plane array that has not been etched to remove the sacrificial layer of the photosensitive absorption region;

A polysilicon layer is deposited on the above substrate.

Wherein, in the manufacturing method of the energy-concentrating micromirror array based on the infrared focal plane array, a plurality of through holes with upper ports not smaller than the lower ports are etched in the polysilicon layer, and the lower ports of the through holes expose infrared light. The photosensitive absorbing region of the focal plane array;

Wherein, the manufacturing method of the infrared focal plane array-based energy-concentrating micromirror array also includes releasing the sacrificial layer of the photosensitive absorption region of the infrared focal plane array.

Compared with the prior art, the present invention has the following advantages:

The energy-concentrating micromirror array based on the infrared focal plane array of the present invention includes a plurality of energy-concentrating micromirror units located at the base, and the energy-concentrating micromirror unit includes a through hole and a microlens whose upper port is not smaller than the lower port, and the microlens Covering the upper port of the through hole; wherein at least one energy-gathering micro-mirror unit includes a micro-mirror, and the through-hole upper port of the energy-gathering micro-mirror unit comprising the micro-mirror is larger than the lower port, and the micro-mirror covers the On the side wall between the upper port and the lower port of the through hole, the microreflector reflects the light incident on the microreflector through the microlens to the lower port of the through hole; The photosensitive absorption region corresponds to the infrared focal plane array. The microlenses arranged on the upper port of the through hole can make the incident light be refracted below it by the microlens. The light from the through hole is reflected to the lower port of the through hole. After the energy-concentrating micromirror array is integrated with the infrared focal plane array, the light passing through the lower port of the through hole in the substrate is absorbed by the photosensitive absorption area of the infrared focal plane array. In this way, the incident light is concentrated in the photosensitive absorption area of the infrared focal plane array after passing through the action of the energy-concentrating micromirror array, so that the wasted "dead light" in the incident light is reduced, and the filling factor of the infrared focal plane array can be improved.

In addition, the energy-concentrating micromirror array of the present invention can be pasted together with the infrared focal plane array by using optical glue, or can directly make the energy-concentrating micromirror array on the infrared focal plane to facilitate the realization of the energy-concentrating micromirror array and the infrared focal plane integrated.

Description of drawings

The above and other objects of the present invention are more clearly shown by the accompanying drawings. Like reference numerals designate like parts throughout the drawings. The drawings are not deliberately scaled and drawn according to the actual size, and the emphasis is on illustrating the gist of the present invention.

Fig. 1 is a schematic diagram of the position of the photosensitive absorption region in the photosensitive element in the infrared focal plane array;

Fig. 2 is the energy-concentrating schematic diagram of increasing the energy-concentrating lens above the photosensitive element of the infrared focal plane array;

Fig. 3 is the top view of existing energy-concentrating micromirror array;

4 to 10 are schematic diagrams of the first embodiment of the present invention;

11 to 12 are schematic diagrams of a second embodiment of the present invention;

Fig. 13 is the production flowchart of the energy-concentrating micromirror array based on the infrared focal plane array of the present invention;

Fig. 14 to Fig. 20 are the flow schematic diagrams of making an energy-gathering micromirror unit among the present invention;

Fig. 21 is a schematic cross-sectional view of the energy-concentrating micromirror array and the infrared focal plane of the present invention pasted together;

22 is a schematic diagram of a third embodiment of the present invention;

Fig. 23 is a schematic diagram of a fourth embodiment of the present invention.

Detailed ways

In the existing infrared focal plane monolithic integrated microlens array technology, the microlens unit in the energy-concentrating microlens array prepared by the "photoresist thermal melting-etching transfer" method has a plane lens that cannot converge the incident light. Only the incident light incident on the convex lens that can converge the incident light in the middle of the unit is concentrated to the photosensitive absorption area of the infrared focal plane, and the incident light irradiated to the flat lens cannot be refracted to the photosensitive absorption area and be wasted. Therefore, the existing monolithic positive The maximum filling factor of the infrared focal plane array integrated microlens array can only reach 78.5%. The microlens in the present invention refers to all devices capable of transmitting light, and is not limited to convex lenses and concave lenses.

The present invention proposes an energy-concentrating micromirror array based on an infrared focal plane array. The incident light irradiated to the energy-concentrating micromirror array is converged to the photosensitive absorption area of the infrared focal plane array by combining a microlens and a microreflector. , which can improve the fill factor of the infrared focal plane. In order to make the above objects, features and advantages of the present invention more comprehensible, specific implementations of the present invention will be described in detail below in conjunction with the accompanying drawings.

In the following description, a lot of specific details are set forth in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described here, and those skilled in the art can do it without departing from the meaning of the present invention. By analogy, the present invention is therefore not limited to the specific examples disclosed below.

Secondly, the present invention is described in detail in combination with schematic diagrams. When describing the embodiments of the present invention in detail, for the convenience of explanation, the cross-sectional view showing the device structure will not be partially enlarged according to the general scale, and the schematic diagram is only an example, and it should not be limited here. The protection scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in actual manufacturing.

Embodiment one:

In this embodiment, the microlenses are thin-layer convex lenses, and the substrate is bulk silicon, but other materials can also be used.

The schematic top view of the energy-concentrating micromirror array based on the infrared focal plane array of the present invention is shown in Fig. In the through hole in bulk silicon, the size of the upper port 301 of the through hole is larger than that of the lower port 302, and the inner wall of the through hole is covered with a microreflector 303, and the microlens covers the upper port of the through hole, where the microlens is thin laminar lens. In this embodiment, the upper and lower ports of the through hole are both square, and the inner surface of the through hole includes four planes. In order to show the structure of the concentrated micromirror array more clearly, FIG. 5 is a cross-sectional view along line AB in FIG. 4 . Wherein, the energy-concentrating micromirror array includes an energy-concentrating micromirror unit 300 (shown in a dashed box), and the energy-concentrating micromirror unit 300 includes bulk silicon 304 , microreflectors 303 and microlenses 306 . The bulk silicon 304 includes a through hole 305, the micro mirror 303 covers the inner side wall of the through hole, the upper port of the through hole is larger than the lower port, and the microlens 306 is a thin layer convex lens, and the edge of the thin layer convex lens is aligned with the upper port of the through hole. coincide. The thin-layer convex lens in this embodiment refracts the parallel incident light to the lower port of the through hole or the inner wall of the micro-reflector, and the micro-reflector reflects the light irradiated on the micro-mirror to the lower port of the through-hole.

After the energy-concentrating micromirror array and the infrared focal plane array of the present embodiment are forwardly integrated, see FIG. The light at the port under the hole can be absorbed by the photosensitive absorption area of the infrared focal plane array, and the invention can reduce the wasted "dead light" in the incident light and improve the filling factor of the infrared focal plane array.

The shape of the lower port of the through hole in the substrate of this embodiment can be different from that of the upper port, for example, it can be circular, and the side wall of the through hole is arc-shaped; the micro-mirror can partially cover the inner side wall of the through hole, for example, only cover the inner side wall of the through hole. near the inner side of the upper port.

According to the arrangement of the photosensitive absorption regions in the infrared focal plane array, the shape of the bottom end of the thin-layer convex lens in this embodiment can be a square, a rectangle or a parallelogram. In the energy-concentrating micromirror array of this embodiment, when the ports on the through holes of adjacent energy-concentrating micromirrors are connected together, they may be closely arranged, or may not be closely arranged according to the arrangement of the photosensitive absorption regions.

The reflective surface material of the microreflector in this embodiment is metals such as aluminum, copper or iron, such as polished aluminum, rough surface aluminum, common aluminum, polished copper, bronze, copper oxide, ferrous oxide, iron oxide, polished iron, Galvanized shiny iron etc. The material of the reflective surface may also be an alloy material, such as copper-nickel alloy, Inconel alloy, and the like. The microlens material is silicon or organic, such as polycarbonate PC, polystyrene PS or photoresist.

The microlens in the present embodiment also can adopt the shell lens of other shapes, and Fig. 7 is the sectional schematic view that adopts shell spherical lens as microlens, and shell elliptic lens 315 is positioned at the upper port of the through hole in bulk silicon 314 , whose edge coincides with the upper port of the via. 8 is a schematic cross-sectional view of using a shell-shaped planar lens as a microlens. The shell-shaped planar lens 325 is located at the upper port of the through-hole of the bulk silicon 324, and its edge coincides with the upper port of the through-hole. The shell-shaped ellipsoid lens and the shell-shaped planar lens are made of polycarbonate PC or polystyrene PS. 9 is a schematic cross-sectional view of a diffractive microlens. The diffractive microlens 335 is located at the upper port of the through hole in the bulk silicon 334, and its edge coincides with the upper port of the through hole. The material of the diffractive microlens is polyolefin or glass, one surface of which is flat, and the other side is engraved with concentric circles ranging from small to large. The top view of the diffractive microlens is shown in Figure 10.

Embodiment two:

The microlenses used in this embodiment include microlenses in the middle that can converge incident light and microlenses that cannot converge incident light at the edge. The through holes covered with microreflectors are made in bulk silicon, and can also be made in other materials.

The sectional view of the energy-gathering micromirror array based on the infrared focal plane array of the present embodiment is shown in Fig. 11, and the energy-gathering micromirror array comprises the energy-gathering micromirror unit 400 (shown in the dotted line frame), and the energy-gathering micromirror unit 400 includes Vias in bulk silicon 401, micromirrors 402 and microlenses 403. Wherein, the lower surface of the microlens 403 is flat; the edge of the upper surface is flat, and the middle part is convex upward. The middle part of the microlens 403 is a convex lens capable of converging incident light, and the edge is a flat lens that cannot converging light. The micro-mirror 402 covers the inner surface of the through-hole whose upper port is larger than the lower port, and the outer edge of the micro-lens 403 coincides with the upper port of the through-hole. The micro lens 403 in this embodiment refracts the parallel incident light to the lower port of the through hole or the micro mirror, and the micro mirror reflects the light irradiated on it to the lower port of the through hole. After the energy-concentrating micromirror array of this embodiment is integrated with the infrared focal plane array, the light passing through the lower port of the microreflector can be absorbed by the photosensitive absorption area of the infrared focal plane array. Light" is reduced, improving the fill factor of the infrared focal plane array. The shape of the bottom end of the convex lens in the middle of the microlens can be circular, regular hexagonal, square or the like.

The microlens of this embodiment can also use an organic thin-shell lens. FIG. 12 is a schematic cross-sectional view of using an organic thin-shell lens as a microlens. The middle part of the organic shell-shaped lens 413 is a shell-shaped convex lens capable of converging incident light rays, and the edge is a plane lens that cannot converge light rays. The microlens is located at the upper port of the through-hole in the bulk silicon 411 , and its outer edge coincides with the upper port of the through-hole.

The process flow of the manufacturing method of the infrared focal plane array-based energy-concentrating micromirror array of the present invention is shown in Figure 13, including:

Step S1, etching a plurality of through holes with upper ports not smaller than the lower ports on the substrate, and the lower ports of the through holes correspond to the photosensitive absorption regions of the IRFPA;

Step S2, making a micro-mirror and a micro-mirror protective layer on the side wall of the through hole where the upper port is larger than the lower port;

Step S3, filling the microlens sacrificial material in the through hole of the substrate;

Step S4, fabricating a microlens on the through hole filled with a microlens sacrificial material;

Step S5 , releasing the sacrificial material of the microlens and the protective layer of the micromirror in the through hole.

In order to realize the fabrication of the energy-concentrating micromirror array based on the infrared focal plane array of the present invention, two kinds of substrates can be used to realize the fabrication of the energy-concentrating micromirror array of the present invention. One is based on bulk silicon or other materials, on which the energy-concentrating micromirror array based on the infrared focal plane array of the present invention is fabricated; A sacrificial layer in the area, a polysilicon layer is deposited on the photosensitive absorption area of the infrared focal plane, and an energy-concentrating micromirror array is fabricated on the multi-layer silicon as a base.

When making energy-concentrating microlenses, the fabrication methods of microlenses include photoresist thermal melting-etching transfer method and organic compound thermal melting expansion method. Below in conjunction with accompanying drawing, take an energy-gathering micromirror unit of the present embodiment as an example to specifically introduce the manufacturing steps of the present invention:

Step S1, etching a plurality of through holes on the substrate with upper ports not smaller than the lower ports, and the lower ports of the through holes correspond to the photosensitive absorption regions of the IRFPA.

As shown in FIG. 14 , a photoresist 501 is spin-coated on the double-sided polished bulk silicon 500 and photoetched into a parallelogram or a regular hexagon. A KOH solution is used to etch through holes 502 closely arranged in the bulk silicon, including through holes with upper ports larger than lower ports. Here the edge thickness of the port on the via is exaggerated, in reality the edge of the port on the via is very small.

Step S2, fabricating a micro-mirror and a micro-mirror protective layer on the side wall of the through hole where the upper port is larger than the lower port.

Referring to FIG. 15 , a metal aluminum layer 503 is sputtered in the through hole 502 in the bulk silicon, and the thickness of the metal aluminum layer is about 200 nm. Copper, iron or nickel alloy materials can also be used as the mirror material, and the surface of the mirror can be a mirror surface, a matte surface, or the like.

Then a silicon dioxide layer 504 is deposited on the surface of the reflector using a low temperature deposition method. The function of this layer of silicon dioxide is to protect the metal aluminum layer in the subsequent manufacturing process. Then the metal aluminum and silicon dioxide at the lower port of the through hole are etched away, and finally the photoresist 501 on the upper surface of the bulk silicon is etched away.

Step S3, filling the microlens sacrificial material in the through hole of the substrate;

As shown in FIG. 16 , the organic glass polymer 505 is filled in the through hole deposited with the silicon dioxide layer 504 as a microlens sacrificial layer, the organic glass polymer remaining outside the through hole is removed, and the organic glass polymer is subjected to exposure treatment 506.

Step S4, fabricating a microlens on the through hole filled with a microlens sacrificial material;

Firstly, the photoresist thermal melting-etching transfer method for fabricating microlenses is described in detail.

The microlens will be made below. The middle part of the microlens made in this embodiment is a convex lens that can converge the incident light, and the edge is a plane lens that cannot converge the incident light. It is made by photoresist thermal melting-etching transfer method.

As shown in FIG. 17 , a silicon substrate 507 is deposited on the surface of the exposed organic glass polymer and etched into a designed shape. The height of the silicon substrate is determined by the height of the designed microlens. The photoresist 508 is spin-coated on the silicon substrate layer, and after the photoresist is planarized, it is etched into the shape of the bottom end of the microlens.

A layer of ZnS can also be deposited on the finished microlens to increase the transmittance of silicon to infrared rays.

Put the above-treated bulk silicon into a gradient incubator, keep the temperature within the temperature range of photoresist thermal melting and heat for two hours, the photoresist is melted to form a photoresist micro-lens, and then use argon ions to etch the transfer pattern On the silicon substrate, a microlens 509 as shown in FIG. 18 is formed, the middle of the microlens is a convex lens, and the edge is a plane mirror.

For the fabrication of microlenses by thermally melting and expanding organic materials, the fabrication process will be described in detail below.

As shown in Figure 19, an organic substance 516 is spin-coated on the surface of the exposed plexiglass polymer 505, the organic substance is polycarbonate PC or polystyrene PS, and the above-mentioned treated bulk silicon is placed in a constant temperature box, and the temperature is kept After heating for a period of time within the temperature range of the thermal melting of the organic matter, the organic matter melts and expands to form organic microlenses, as shown in Figure 20.

Finally, release the sacrificial material organic glass polymer under the microlens to form a cavity under the microlens, and use CF4 (carbon tetrafluoride) and CHF3 (trifluoromethane) dry etching to remove the protective layer silicon dioxide of the microreflector. So far, the energy-concentrating micromirror unit of the present invention has been fabricated.

After the energy-concentrating micromirror array of the present invention is made using bulk silicon as the substrate, the energy-concentrating micromirror array and the infrared focal plane array can be pasted together with optical glue, as shown in Figure 21, and the energy-concentrating micromirror array is glued together with optical glue 512. 513 is pasted together with the infrared focal plane array 510, so that the lower port of the through hole 514 in the energy-concentrating micromirror unit corresponds to the photosensitive absorption region 511 of the infrared focal plane array, and the incident light is incident on the through hole through the microlens and the microreflector All light from the lower port is incident on the photosensitive absorption area, and the readout circuit and transmission circuit layer 513 under the photosensitive absorption area passing through the infrared focal plane read out the detection results of the infrared focal plane. The integration of the energy-gathering micromirror array and the infrared focal plane reduces the wasted "dead light" in the incident light, which is beneficial to improving the filling factor of the infrared focal plane array.

It is also possible to deposit a polysilicon layer on the photosensitive absorption area of the infrared focal plane without releasing the sacrificial layer of the photosensitive absorption area after the photosensitive absorption area of the infrared focal plane is made, and use the polysilicon as a base to fabricate an energy-concentrating micromirror array thereon. In this method, the lower port of the through hole etched in polysilicon needs to expose the photosensitive absorption region. After the micro-mirrors and microlenses are fabricated, the sacrificial layer under the microlens and the photosensitive absorption region sacrificial layer under the photosensitive absorption region are released together.

Embodiment three:

In this embodiment, in addition to the first through hole and the first microlens, the energy-concentrating micromirror unit also includes the second through hole and the second microlens in the substrate, and the upper port of the second through hole is connected to the first through hole. The upper port of the through hole has one side; the second microlens covers the upper port of the second through hole, and refracts all the light incident on the second microlens to the lower port of the second through hole; The lower port of the second through hole corresponds to the photosensitive absorption area of the infrared focal plane array. A schematic cross-sectional view of the energy-concentrating micromirror array based on the infrared focal plane array of this embodiment is shown in FIG. 21 . The energy-concentrating micromirror unit 600 (shown in the dotted line frame) includes a micromirror 601 covering the sidewall of the first through hole, a microlens 602 covering the upper port of the first through hole, a second through hole adjacent to the first through hole A hole 603 and a second microlens 604 covering the port on the second through hole. The microlens in this embodiment includes a lens that can converge light in the middle and a lens that cannot converge light at the edge. The upper port of the micromirror 601 covering the through hole coincides with the edge of the lens that cannot converge light around the microlens 602 . After the energy-concentrating micromirror array of this embodiment is integrated forwardly with the infrared focal plane array, the light that passes through the microlens 602 is refracted to the lower port of the through hole or the micromirror 601, and the light irradiated on it by the microreflector Reflected to the lower port of the covered through hole, the lens in the middle of the microlens 604 capable of converging light converges the light irradiated on it to the photosensitive absorption region of the focal plane below it. The energy-concentrating micromirror array of this embodiment can reduce the wasted "dead light" in the incident light, and improve the filling factor of the infrared focal plane array.

Embodiment four:

In this embodiment, in addition to the first micro-mirror covering the inner wall of the through-hole in the energy-concentrating micro-mirror unit, a second micro-mirror with a reflective surface is included between the upper port of the through-hole and the micro-lens. The sectional view of the energy-concentrating micromirror array based on the infrared focal plane array of the present embodiment is shown in FIG. Microlens 702 and the second microreflector 703, the microlens in this embodiment is to comprise the lens that can converge light in the middle and the lens that edge can't converge light, the upper port of the second microreflector 703 coincides with the edge of microlens 702 , the lower port of the second micro-mirror 703 coincides with the upper port of the micro-mirror 701, and the side surface of the second micro-mirror 703 is a reflective surface.

The above descriptions are only preferred embodiments of the present invention, and do not limit the present invention in any form.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person familiar with the art, without departing from the scope of the technical solution of the present invention, can use the methods and technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent implementation of equivalent changes example. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention, which do not deviate from the technical solution of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims (20)

1. the cumulative micro mirror array based on infrared focal plane array is characterized in that, comprises a plurality of cumulative micro mirror unit that are positioned at substrate,

Described cumulative micro mirror unit comprises through hole, lenticule, wherein,

The upper port of described through hole is not less than lower port, is the sidewall of through hole between upper port and the lower port;

Described lenticule covers the upper port of described through hole;

Wherein, comprise micro-reflector at least one cumulative micro mirror unit,

The through hole upper port of the described cumulative micro mirror unit that comprises micro-reflector is greater than lower port;

Micro-reflector covers the sidewall of described through hole, and described micro-reflector will be incident on light reflection on the micro-reflector to the lower port of through hole by lenticule;

The through hole lower port is corresponding with the photosensitive uptake zone of infrared focal plane array in the described cumulative micro mirror unit.

2. the cumulative micro mirror array based on infrared focal plane array according to claim 1 is characterized in that, the upper port close-packed arrays of through hole forms void-free plane in a plurality of described cumulative micro mirror unit.

3. the cumulative micro mirror array based on infrared focal plane array according to claim 2 is characterized in that, the upper port of through hole is parallelogram, square or regular hexagon in the described cumulative micro mirror unit.

4. the cumulative micro mirror array based on infrared focal plane array according to claim 1 is characterized in that, all comprises micro-reflector in the described cumulative micro mirror unit.

5. the cumulative micro mirror array based on infrared focal plane array according to claim 2 is characterized in that, the lower port of through hole is identical with the upper port shape in the described cumulative micro mirror unit, and the sidewall of through hole comprises a plurality of planes.

6. the cumulative micro mirror array based on infrared focal plane array according to claim 2 is characterized in that, the lower port of through hole is circular in the described cumulative micro mirror unit, and the madial wall of through hole is curved surface.

7. according to claim 1 to 6 each described cumulative micro mirror arrays based on infrared focal plane array, it is characterized in that, can converge the lenticule of incident light and the lenticule that the edge can not converge incident light in the middle part of the lenticule in the described cumulative micro mirror unit comprises.

8. the cumulative micro mirror array based on infrared focal plane array according to claim 7 is characterized in that, described cumulative micro mirror unit also comprises the second through hole and the second lenticule that is arranged in substrate except the first through hole and the first lenticule, wherein,

The upper port of the upper port of described the second through hole and the first through hole has a limit;

Described the second lenticule covers the upper port of described the second through hole, will incide light on the second lenticule and all be refracted to the lower port of the second through hole;

The lower port of described the second through hole is corresponding with the photosensitive uptake zone of infrared focal plane array.

9. according to claim 1 to 6 each described cumulative micro mirror arrays based on infrared focal plane array, it is characterized in that, in the described cumulative micro mirror unit except the first micro-reflector that covers the through hole madial wall, comprise also between through hole upper port and the lenticule that the surface is the second micro-reflector of reflecting surface, this second micro-reflector is perpendicular to substrate, upper port is identical with the lower port shape, and lower port overlaps with the upper port of through hole.

10. according to claim 1 to 6 each described cumulative micro mirror arrays based on infrared focal plane array, it is characterized in that, the micro-reflector material in the described cumulative micro mirror unit is aluminium, copper, iron or nickel alloy.

11. to 6 each described cumulative micro mirror arrays based on infrared focal plane array, it is characterized in that according to claim 1, the lenticule in the described cumulative micro mirror unit is refractive lenses or diffraction type lens.

12. to 6 each described cumulative micro mirror arrays based on infrared focal plane array, it is characterized in that according to claim 1, the lenticule in the described cumulative micro mirror unit is convex lens.

13. the cumulative micro mirror array based on infrared focal plane array according to claim 11 is characterized in that the convex lens material in the described cumulative micro mirror unit is silicon.

14. to 6 each described cumulative micro mirror arrays based on infrared focal plane array, it is characterized in that according to claim 1, the lenticule in the described cumulative micro mirror unit is shelly dome shape lens or the plane lens of shelly.

15. to 6 each described cumulative micro mirror arrays based on infrared focal plane array, it is characterized in that according to claim 1, the microlens material in the described cumulative micro mirror unit is polycarbonate or polystyrene PS.

16. the manufacture method based on the cumulative micro mirror array of infrared focal plane array is characterized in that, comprising:

Etch the through hole that a plurality of upper port are not less than lower port in substrate, the lower port of through hole is corresponding with the photosensitive uptake zone of IRFPA;

Make micro-reflector and micro-reflector protective layer in upper port greater than the through-hole side wall of lower port;

In the through hole of substrate, fill the lenticule expendable material;

Make lenticule in the through hole upper port that is filled with the lenticule expendable material;

Discharge lenticule expendable material and micro-reflector protective layer in the through hole.

17. the cumulative micro mirror array manufacture method based on infrared focal plane array according to claim 16 is characterized in that, also comprises:

Adopt optical cement will be manufactured with micro-reflector and lenticular substrate and infrared focal plane array and paste, make the lower port of through hole corresponding with the photosensitive uptake zone of infrared focus plane.

18. the manufacture method of the cumulative micro mirror array based on infrared focal plane array according to claim 16 is characterized in that, comprises the substrate fabrication step:

Remove the infrared focal plane array of photosensitive uptake zone sacrifice layer as substrate take etching not;

Deposit spathic silicon layer on above-mentioned substrate.

19. the manufacture method of the cumulative micro mirror array based on infrared focal plane array according to claim 18 is characterized in that,

Etch the through hole that a plurality of upper port are not less than lower port in described polysilicon layer, the lower port of described through hole is exposed the photosensitive uptake zone of infrared focal plane array.

20. according to claim 18 or the manufacture method of 19 described cumulative micro mirror arrays based on infrared focal plane array, it is characterized in that, also comprise the sacrifice layer of the photosensitive uptake zone that discharges infrared focal plane array.

Images