Preparation method of infrared detector and infrared detector

Abstract

The invention relates to a preparation method of an infrared detector and the infrared detector. The method comprises the following steps: S1, sequentially forming a reflector metal layer and a first passivation layer on a substrate; s2, forming a reflector pattern on the first passivation layer; s3, etching and removing part of the first passivation layer according to the reflector pattern to form an anchor post generation region; s4, sequentially forming an anchor column metal layer on the substrate, wherein the anchor column metal layer fills the anchor column generation region and covers the first passivation layer; s5, forming an anchor column base pattern on the anchor column metal layer, wherein the anchor column base pattern surrounds the outer side of the reflector pattern; and S6, etching the anchor post metal layer and the reflector metal layer through the anchor post base pattern and the reflector pattern to form an anchor post base and a reflector. According to the preparation method, the curing operation in the prior art is broken through, and the problem of overlay errors caused by step-by-step photoetching of the anchor post base and the reflector in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and more particularly, to a method for manufacturing an infrared detector and an infrared detector. Background Art

[0002] As a core component of current thermal imaging technology, the uncooled vanadium oxide infrared detector has high performance that is inseparable from its precise structure design. The detector typically includes multiple key components such as a readout circuit, a mirror, an optical resonator, anchor posts, support legs, and a thermistor. Among these components, the thermistor is suspended above the mirror through the anchor posts to construct a resonator that is precisely adjusted to a quarter of the incident infrared wavelength. This structure enhances the absorption efficiency of infrared radiation, thereby improving the sensitivity and performance of the detector.

[0003] In the design of the anchor posts 200, the prior art mainly includes two forms: fully hollow (as shown in Figure 1-1 ) and partially hollow (as shown in Figure 1-2 ). Among them, as shown in Figure 1-2 , the partially hollow anchor posts 200 (characterized by a solid lower end, which can be called the anchor post base 201, and a hollow upper end, which can be called the hollow anchor post part 202) have occupied a dominant position in practical applications due to their excellent mechanical stability. Some of the preparation methods for infrared detectors with partially hollow anchor posts in the prior art include:

[0004] Please refer to Figure 3-1 and Figure 3-2 , deposit an anchor post metal layer 20 (made of aluminum) on a substrate 100 through sputtering technology, and then perform coating, exposure, and development steps to form an anchor post pattern 30;

[0005] Please refer to Figure 3-3 and Figure 3-4 , through etching and stripping processes, form the anchor post base 201, and at the same time form a reflective layer metal 40 (made of aluminum) on the anchor post base 201;

[0006] Please refer to Figure 3-5 and Figure 3-6 , through coating, exposure, and development steps, form a mirror pattern 50; through etching and stripping steps, form a mirror 300.

[0007] However, although the locally hollow anchor posts have many structural advantages, the existing preparation process has the following problems: First, since the height of the anchor posts (especially aluminum posts) usually reaches 1000 - 1200 nm, this height will hinder the fluidity of the photoresist during the photolithography coating of the mirror, easily leading to problems such as uneven or poor coating. Second, the overlay accuracy requirements between the mirror and the anchor posts are extremely high, and any minor deviation may cause damage to the anchor posts during the etching process, thereby making their size smaller than the designed value, adding difficulty to the subsequent overlay for fabricating the hollow anchor post part. In addition, the high step effect of the anchor posts also requires a relatively thick photoresist layer for mirror photolithography. However, an overly thick photoresist layer not only increases the exposure difficulty and is prone to incomplete exposure problems, resulting in short circuits between the anchor posts and the mirror, thus causing the detector to fail; at the same time, an overly thick photoresist may also exceed the resolution capability range of the lithography machine, making it difficult to effectively control the uniformity of the lithography line width. Summary of the Invention

[0008] The object of the present invention is to provide a preparation method for an infrared detector, which can avoid overlay errors and also reduce the manufacturing difficulty of the mirror.

[0009] To achieve the above object, the present invention provides the following technical solution: A preparation method for an infrared detector, comprising:

[0010] S1: Sequentially form a mirror metal layer and a first passivation layer on a substrate;

[0011] S2: Form a mirror pattern on the first passivation layer;

[0012] S3: According to the mirror pattern, etch away part of the first passivation layer to form an anchor post generation area;

[0013] S4: Then sequentially form an anchor post metal layer on the substrate, and the anchor post metal layer fills the anchor post generation area and covers the first passivation layer;

[0014] S5: Form an anchor post base pattern on the anchor post metal layer;

[0015] S6: Etch the anchor post metal layer and the mirror metal layer through the anchor post base pattern and the mirror pattern to form an anchor post base and a mirror.

[0016] Further, in step S6, it specifically includes:

[0017] According to the anchor post base pattern, use a first etching gas to etch the anchor post metal layer until the etching position reaches the first passivation layer;

[0018] Use a second etching gas to continue etching the mirror metal layer until an anchor post base and a mirror are formed;

[0019] Among them, the first etching gas is a chlorine-based highly active etching agent; the second etching gas is a chlorine-bromine composite selective etching agent.

[0020] Furthermore, the total deposition thickness H of the first passivation layer satisfies:

[0021] H = H1 + H2;

[0022] wherein, H1 represents the thickness of the first passivation layer to be retained after etching with the second etching gas; H2 represents the loss thickness of the first passivation layer during the etching process with the second etching gas.

[0023] Furthermore, the total deposition thickness of the first passivation layer is 250 - 300 nm.

[0024] Furthermore, the first etching gas is a mixed gas containing chlorine and boron trichloride, and the second etching gas is specifically a mixed gas containing chlorine, boron trichloride, and hydrogen bromide.

[0025] Furthermore, the ratio of chlorine to boron trichloride in the first etching gas is 2:1 - 4:3; the ratio of chlorine to boron trichloride to hydrogen bromide in the second etching gas is 2:1:1 - 4:3:1.

[0026] Furthermore, the materials selected for the mirror metal layer and the anchor post metal layer are aluminum.

[0027] Furthermore, the material selected for the first passivation layer is silicon dioxide or silicon nitride.

[0028] Furthermore, the preparation method further includes:

[0029] S7: Form a sacrificial layer and a photoresist layer on the substrate;

[0030] S8: Etch the photoresist layer and the sacrificial layer to thin the sacrificial layer;

[0031] S9: Perform photolithography and etching on the sacrificial layer to form an anchor post hollow hole;

[0032] S10: Deposit a second passivation layer, the second passivation layer fills the anchor post hollow hole, and perform photolithography and etching on the second passivation layer to form a wiring pattern;

[0033] S11: Deposit a third metal layer, and perform photolithography and etching on the third metal layer to fabricate a hollow anchor post portion.

[0034] This application also provides an infrared detector, which is fabricated by using the above preparation method of the infrared detector.

[0035] The beneficial effects of the present invention are as follows:

[0036] 1. The preparation method of the infrared detector of the present application forms the mirror metal layer and the first passivation layer first, and then forms the anchor post base and the mirror by synchronous etching, breaking the curing operation of the prior art, avoiding the interference of the anchor post base when manufacturing the mirror, and moreover, when manufacturing the mirror, there is no need to use a too thick photoresist layer to cope with the high step effect in the prior art, reducing the exposure difficulty, avoiding the risks of incomplete exposure and short circuit between the anchor post and the mirror; more importantly, this preparation method eliminates the problem of overlay error caused by lithographing the anchor post base and the mirror step by step in the existing process; at the same time, it can also avoid etching damage to the anchor post due to overlay deviation.

[0037] 2. The present application uses the mirror pattern and the anchor post generation area to ensure the positions of the subsequent anchor post base and the mirror, enabling precise alignment of the anchor post base etching and the mirror etching without additional calibration steps.

[0038] 3. By adopting the preparation method of the infrared detector of the present application, the problem of overlay error is solved and precise positioning of the anchor post base and the mirror is achieved, which helps to improve the device performance and reduce the manufacturing cost.

[0039] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly and implement it according to the content of the specification, the following takes the preferred embodiments of the present invention and describes them in detail in conjunction with the drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1-1 、 Figure 1-2 is a schematic structural diagram of the anchor posts of two infrared detectors in the prior art;

[0041] Figure 2 is a schematic structural diagram of the infrared detector in the present application;

[0042] Figures 3-1 to 3-6 A schematic preparation process diagram of a part of the structure of an infrared detector in the prior art.

[0043] Figure 4 is a flowchart of the preparation method of the infrared detector shown in an embodiment of the present application;

[0044] Figures 5-1 to 5-11 A schematic preparation process diagram of the infrared detector shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the protection scope of the present invention.

[0046] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0047] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0048] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0049] Please refer to Figure 2 the structural schematic diagram of the infrared detector in, the infrared detector includes a substrate 100, a local hollow anchor post 200 formed on the substrate 100, a mirror 300 formed inside the local hollow anchor post 200, and a thermistor 400 supported by the local hollow anchor post 200. The mirror 300 is located below the thermistor 400. The local hollow anchor post 200 includes an anchor post base 201 and a hollow anchor post portion 202 formed on the anchor post base 201.

[0050] As described in the background art, the current manufacturing process of infrared detectors faces a series of challenges, and the problem of registration error is particularly prominent. To solve this problem, the conventional practice in the industry is to compensate for the registration error to solve this problem. For example, according to the discussion in "Advanced Lithography Theory and Applications for Very Large Scale Integrated Circuits" (written by Wei Yayi, the first edition in June 2016), those skilled in the art have tried to solve this problem by establishing an analysis model and compensating and feedback for the registration error, but there are still many difficulties in actual operation.

[0051] Specifically, differences in overlay problems may occur between different wafers in the same batch, between different regions of the same wafer, and between the status changes of the lithography machine before and after maintenance, which makes it extremely difficult to use a single or multiple models for accurate compensation. Therefore, existing overlay error solutions often fail to achieve ideal results in practical applications.

[0052] In addition, in the process of manufacturing infrared detectors, the incompatibility between vanadium oxide and ASIC also limits the innovation of the manufacturing process. Due to the solidification of the distribution manufacturing method of reflectors and anchor columns in the existing technology, the existing optimization process is often limited to the following aspects:

[0053] 1. Edge Bead Removal (EBR): Although this method can improve the uniformity of the glue layer to a certain extent, it cannot fundamentally eliminate the mutation effect of the anchor column area morphology, so its effect is limited.

[0054] 2. Multi-layer Resist: By introducing a bottom-layer planarizing glue (such as PMGI) to reduce the step height, although this method can alleviate the overlay error problem to a certain extent, it undoubtedly increases the complexity and cost of the process and is not conducive to large-scale production.

[0055] 3. Electron beam lithography (E-beam Lithography): Although electron beam lithography technology can significantly improve overlay accuracy, its high equipment cost makes this method difficult to meet mass production needs, and therefore is limited in practical applications.

[0056] In order to overcome the technical problems existing in the prior art and to overcome the rigid operation of the manufacturing process caused by the incompatibility between vanadium oxide and ASIC, the manufacturing method of the infrared detector of the present application first forms a reflector metal layer and a first passivation layer, and then forms the anchor column base 201 and the reflector 300 by synchronous etching, thereby eliminating the problem of overlay error caused by the step-by-step photolithography of the anchor column base 201 and the reflector 300 in the prior art.

[0057] Please combine Figure 4 , the preparation method of the infrared detector of the present application comprises:

[0058] S1: Please combine Figure 5-1 , forming a reflector metal layer 310 and a first passivation layer 510 in sequence on the substrate 100;

[0059] S2: Please combine Figure 5-2 , forming a reflector pattern on the first passivation layer 510, the reflector pattern being formed by exposing the first photoresist layer 610;

[0060] S3: Please combine with Figure 5-3 , etch away part of the first passivation layer 510 according to the mirror pattern to form an anchor post generation region 203 on the first passivation layer 510, and stop etching on the mirror metal layer 310;

[0061] S4: Please combine with Figure 5-4 , and then sequentially form an anchor post metal layer 210 and a second photoresist layer 520 on the substrate 100. The anchor post metal layer 210 fills the anchor post generation region 203 and covers the first passivation layer 510;

[0062] S5: Please combine with Figure 5-5 , form an anchor post base pattern on the anchor post metal layer 210. The anchor post base pattern is formed by exposing the second photoresist layer 520. In the projection direction perpendicular to the surface of the substrate 100, the anchor post base pattern surrounds the outside of the mirror pattern, and the anchor post base pattern is correspondingly formed above the anchor post generation region 203;

[0063] S6: Please combine with Figure 5-5 and Figure 5-6 , etch the anchor post metal layer 210 and the mirror metal layer 310 through the anchor post base pattern and the mirror pattern to form an anchor post base 201 and a mirror 300;

[0064] S7: Please combine with Figure 5-7 , form a sacrificial layer 710 and a third photoresist layer 620 on the substrate 100. The material of the sacrificial layer 710 is polyimide (PI). Specifically, form the sacrificial layer 710 on the substrate 100 and perform high-temperature curing for 30 min. The thickness of the cured sacrificial layer 710 is 4000 ± 400 nm; coat a photoresist material on the sacrificial layer 710, and the thickness of the formed third photoresist layer 620 is 1200 ± 120 nm;

[0065] S8: Please combine with Figure 5-8 , etch the third photoresist layer 620 and the sacrificial layer 710 to thin the sacrificial layer 710. The thickness of the etched sacrificial layer 710 is 2000 ± 200 nm; The purpose of forming the sacrificial layer and the third photoresist layer through step S7 is to planarize the entire wafer, solve the problem that the anchor post base 201 affects the coating uniformity, and ensure that the thickness of the sacrificial layer 710 on the mirror 300 is within the range of 2000 ± 200 nm to ensure the optical performance;

[0066] S9: Please combine with Figure 5-9 , perform photolithography and etching on the sacrificial layer 710 to form an anchor post hollow hole 204;

[0067] S10: Please combine with Figure 5-10, depositing a second passivation layer 530, the second passivation layer 530 filling the anchor column hollow hole 204, performing photolithography and etching on the second passivation layer 530 to form a wiring pattern;

[0068] S11: Please combine Figure 5-11 , deposit a third metal layer, perform photolithography and etching on the third metal layer to form a hollow anchor column portion 202 and a thermistor region 410. The hollow anchor column portion 202 and the anchor column base 201 are combined to form a partial hollow anchor column, and the thermistor region 410 can be used to manufacture a thermistor later.

[0069] The preparation method of the infrared detector first forms the reflector metal layer 310 and the first passivation layer 510, and then forms the anchor column base 201 and the reflector 300 by synchronous etching, breaking the curing operation of the prior art, avoiding the interference of the anchor column base 201 when manufacturing the reflector 300, and no excessively thick photoresist layer is needed to cope with the high step effect in the prior art when manufacturing the reflector 300, thereby reducing the exposure difficulty, avoiding the risk of incomplete exposure and short circuit between the local hollow anchor column 200 and the reflector 300; more importantly, the preparation method eliminates the problem of overlay error caused by the step-by-step photolithography of the anchor column base 201 and the reflector 300 in the prior art; and at the same time, it can also avoid etching damage to the local hollow anchor column 200 due to overlay deviation. The preparation method uses the reflector pattern and the anchor column generation area to ensure the position of the subsequent anchor column base 201 and the reflector 300, so that the etching of the anchor column base 201 and the etching of the reflector 300 are accurately aligned without the need for additional calibration steps.

[0070] In one embodiment, the materials selected for the reflector metal layer 310, the anchor metal layer 210, and the third metal layer are aluminum, and the materials selected for the first passivation layer 510 and the second passivation layer 530 are silicon dioxide (SiO2) or silicon nitride (SiN x Of course, in other embodiments, the reflector metal layer 310 and the anchor metal layer 210 may also be made of other metal materials, such as silver, copper, etc., and the first passivation layer 510 and the second passivation layer 530 may also be made of aluminum oxide (Al2O3), other nitrides or oxides, such as aluminum nitride (AlN), hafnium oxide (HfO2), etc.

[0071] Step S2 is specifically as follows: a first photoresist layer 610 is coated on the first passivation layer 510 with a positive resist and exposed and developed using a mask plate having a reflector pattern (hereinafter referred to as the first mask plate) to form a reflector pattern. The corresponding exposure area is the anchor column forming area 203, and the area outside 203 is the area for subsequent production of the reflector 300.

[0072] Step S5 is specifically as follows: Positive photoresist is coated on the anchor post metal layer 210 to form a second photoresist layer 520, and exposure and development are performed using a photomask plate with an anchor post base pattern (hereinafter referred to as the second photomask plate) to form an anchor post base pattern. This anchor post base pattern is the non-exposed area, and its photoresist is retained, while the photoresist outside the anchor post base pattern is exposed and removed during development.

[0073] In the above steps S2 and S5, the first photomask plate and the second photomask plate are respectively used, that is, two sets of photomask plates are used. In another alternative embodiment, only the first photomask plate can be used. In this embodiment, by only using the first photomask plate, it helps to save manufacturing costs. Specifically:

[0074] S2’: Positive photoresist is coated on the first passivation layer 510 to form a first photoresist layer 610, and exposure and development are performed using the first photomask plate to form an anchor post base pattern. At this time, the area 203 where the anchor post base pattern is located is light-transmissive, and other areas are light-impermeable. According to the characteristics of the positive photoresist, the photoresist in the area 203 where the anchor post base pattern is located is removed by the developer due to being irradiated by light, forming an anchor post formation area 203. Among them, the exposure energy is appropriately increased to increase the line width of 203, and it is advisable that the unilateral is more than 1.5 times the alignment accuracy of the lithography machine, so as to prepare for the subsequent formation of the anchor post 201.

[0075] S5’: Negative photoresist is coated on the anchor post metal layer 210 to form a second photoresist layer 520, and exposure and development are performed using the first photomask plate to form an anchor post base pattern. At this time, the area 203 where the anchor post base pattern is located is light-transmissive, and other areas are light-impermeable. According to the characteristics of the negative photoresist, the photoresist in the area 203 where the anchor post base pattern is located is retained after development due to being irradiated by light, forming an anchor post base pattern.

[0076] In step S6, when etching to form the anchor post base 201 and the mirror 300, a portion of the first passivation layer 510 above the mirror 300 is retained as an etch stop layer, which will serve as a protective layer on the mirror 300. In this way, the mirror 300 is protected by the first passivation layer to avoid being damaged by etching when the anchor post base 201 is formed. However, since the thickness of the metal layer to be etched on the mirror 300 is only the thickness of the anchor post base 201 (usually 1000 nm - 1200 nm), while the total thickness of the anchor post metal layer 210 is the sum of the thicknesses of the anchor post base 201 and the mirror metal layer 310 (the former 1000 nm - 1200 nm plus the latter 200 nm - 300 nm), this will result in: when the metal layer in the anchor post area is etched to the mirror metal layer 310, the protective layer on the mirror 300 may be etched simultaneously. Due to the existence of this problem, in order to ensure that the metal in the anchor post area is completely etched without damaging the mirror 300, those skilled in the art often do not think of using synchronous etching to form the mirror 300 and the anchor post base 201, but choose to fabricate the anchor post first and then fabricate the mirror 300.

[0077] Given that both the mirror metal layer 310 and the anchor post metal layer 210 are made of aluminum, common etching gases include Cl2, BCl3, Ar, and N2. However, due to the difference in thickness between the mirror metal layer 310 and the anchor post base 201, how to avoid etching the mirror 300 while forming the anchor post base 201 has also become one of the technical problems of this application.

[0078] To solve this problem, step S6 specifically includes:

[0079] According to the anchor post base pattern, etch the anchor post metal layer 210 with the first etching gas until the etching position reaches the first passivation layer 510;

[0080] Continue to etch the mirror metal layer 310 with the second etching gas until the anchor post base 201 and the mirror 300 are formed;

[0081] Among them, the first etching gas is a chlorine-based highly active etchant; the second etching gas is a chlorine-bromine composite selective etchant. In one embodiment, the first etching gas is a mixed gas containing chlorine gas (Cl2) and boron trichloride (BCl3), and the second etching gas is specifically a mixed gas containing chlorine gas (Cl2), boron trichloride (BCl3), and hydrogen bromide (HBr). Specifically, the ratio of chlorine gas to boron trichloride in the first etching gas is 2:1 - 4:3; the ratio of chlorine gas to boron trichloride to hydrogen bromide in the second etching gas is 2:1:1 - 4:3:1.

[0082] By using different etching gases in stages, first, the anchor post metal layer 210 is efficiently etched with the first etching gas to form the anchor post base 201. Subsequently, hydrogen bromide (HBr) in the second etching gas has a weaker volatility of silicon tetrabromide (SiBr4) generated therefrom than silicon tetrachloride (SiCl4), and the H element combines with the Cl element, which also reduces the concentration of the Cl element in the reaction gas, thereby improving the selectivity ratio between the first passivation layer 510 and the mirror metal layer 310.

[0083] In addition, in this embodiment, the mirror 300 is further prevented from being etched during the etching process by setting the thickness of the first passivation layer 510. In this way, while ensuring that the anchor post metal layer 210 is etched clean, the mirror 300 is protected from damage. Specifically: the total deposition thickness H of the first passivation layer 510 satisfies:

[0084] H = H1 + H2;

[0085] wherein, H1 represents the thickness of the first passivation layer 510 to be retained after etching with the second etching gas; H2 represents the loss thickness of the first passivation layer 510 during the etching process with the second etching gas, and H2 is determined by calibrating the etching rate and time through preliminary experiments. Through experimental optimization, H is preferably 250 - 300 nm, H1 is preferably 50 - 100 nm, and H2 is preferably 150 - 200 nm.

[0086] This application also provides an infrared detector prepared by the above preparation method. It should be noted that the structure of the manufactured infrared detector is the same as that of the existing infrared detector, and no detailed description thereof will be given here. By adopting the preparation method of the infrared detector of this application, the problem of overlay error is solved and the precise positioning of the anchor post base 201 and the mirror 300 is achieved, which helps to improve the device performance and reduce the manufacturing cost.

[0087] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0088] The above-described embodiments merely represent several implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A method for preparing an infrared detector, characterized in that: include: S1: forming a reflector metal layer and a first passivation layer on a substrate in sequence; S2: forming a reflective mirror pattern on the first passivation layer; S3: etching and removing a portion of the first passivation layer according to the reflector pattern to form an anchor column generation area; S4: forming an anchor pillar metal layer on the substrate in sequence, wherein the anchor pillar metal layer fills the anchor pillar generation area and covers the first passivation layer; S5: forming an anchor column base pattern on the anchor column metal layer; S6: etching the anchor post metal layer and the reflector metal layer through the anchor post base pattern and the reflector pattern to form an anchor post base and a reflector.

2. The method for preparing an infrared detector according to claim 1, characterized in that: The step S6 specifically includes: According to the anchor column base pattern, etching the anchor column metal layer using a first etching gas until the etching position reaches the first passivation layer; Using the second etching gas to continue etching the reflector metal layer until the anchor column base and the reflector are formed; Wherein, the first etching gas is a chlorine-based high-activity etchant; and the second etching gas is a chlorine-bromine composite selective etchant.

3. The method for preparing an infrared detector according to claim 2, characterized in that: The total deposition thickness H of the first passivation layer satisfies: H=H1+H2; Wherein, H1 represents the thickness of the first passivation layer to be retained after etching by the second etching gas; H2 represents the loss thickness of the first passivation layer during the etching process of the second etching gas.

4. The method for preparing an infrared detector according to claim 3, characterized in that: The total deposition thickness of the first passivation layer is 250-300 nm.

5. The method for preparing an infrared detector according to claim 2, characterized in that: The first etching gas is a mixed gas containing chlorine and boron trichloride, and the second etching gas is specifically a mixed gas containing chlorine, boron trichloride and hydrogen bromide.

6. The method for preparing an infrared detector according to claim 5, characterized in that: The ratio of chlorine to boron trichloride in the first etching gas is 2:1-4:3; the ratio of chlorine to boron trichloride to hydrogen bromide in the second etching gas is 2:1:1-4:3:

1.

7. The method for preparing an infrared detector according to claim 1, characterized in that: The material used for the reflector metal layer and the anchor column metal layer is aluminum.

8. The method for preparing an infrared detector according to claim 1, characterized in that: The material of the first passivation layer is silicon dioxide or silicon nitride.

9. The method for preparing an infrared detector according to claim 1, characterized in that: The preparation method further comprises: S7: forming a sacrificial layer and a photoresist layer on the substrate; S8: etching the photoresist layer and the sacrificial layer to thin the sacrificial layer; S9: performing photolithography and etching on the sacrificial layer to form a hollow hole for the anchor column; S10: depositing a second passivation layer, the second passivation layer filling the hollow hole of the anchor column, and performing photolithography and etching on the second passivation layer to form a wiring pattern; S11: depositing a third metal layer, and performing photolithography and etching on the third metal layer to produce a hollow anchor column portion.

10. An infrared detector, characterized in that: The infrared detector is manufactured by the method for manufacturing an infrared detector according to any one of claims 1 to 9.

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