Method for processing surface photonic crystal structure of mercury cadmium telluride infrared detector and application

Abstract

The application discloses a processing method and application of a surface photonic crystal structure of a mercury cadmium telluride infrared detector, and comprises the following steps: coating photoresist with a preset thickness on the surface of a mercury cadmium telluride chip; exposing and developing the part of the cadmium zinc telluride substrate of the mercury cadmium telluride chip that needs to be removed by using a photoetching device, so as to expose the part; removing the exposed part of the cadmium zinc telluride substrate; removing the photoresist; coating photoresist with a specified thickness on the surface of the mercury cadmium telluride chip again; transferring the pattern of the photonic crystal from a mask plate to the surface of the infrared detector chip by using mask exposure and development; and etching the cadmium zinc telluride substrate by using a cadmium zinc telluride etching solution, so as to remove the cadmium zinc telluride substrate with the specified thickness, and performing dry etching on the pattern of the photonic crystal. The method of the application realizes the replacement of the original antireflection film structure by the photonic crystal structure, realizes high-efficiency antireflection in the whole spectral response range of the detector, and greatly improves the performance of the mercury cadmium telluride infrared detector.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a method for fabricating a photonic crystal structure on the surface of a mercury cadmium telluride infrared detector and its application. Background Technology

[0002] Infrared focal plane array (FLA) detection technology boasts significant advantages such as a wide spectral response band, the ability to acquire more information about ground targets, and the capacity to operate day and night. It is widely used in fields such as agricultural and pastoral surveys, development and management of forest resources, weather forecasting, geothermal distribution, earthquake and volcanic activity detection, and space astronomical exploration. Mercury cadmium telluride (MDT) infrared detectors are one of the representative products of infrared detection technology and represent an important development direction for next-generation infrared detectors. To reduce the reflection of incident light signals on the surface of MDT infrared detectors and improve the detector's signal collection capability, an anti-reflection coating is typically fabricated on its surface. However, traditional anti-reflection coatings only achieve anti-reflection effects within a very small range around a specific wavelength corresponding to their thickness; therefore, the overall anti-reflection effect across the spectral response range of MDT infrared detectors is poor. Summary of the Invention

[0003] This application provides a method for fabricating a photonic crystal structure on the surface of a mercury cadmium telluride infrared detector and its application. The photonic crystal structure is fabricated on the surface of the mercury cadmium telluride infrared detector using a high-design-fit fabrication method, replacing the original antireflection film structure. This achieves efficient antireflection across the entire spectral response range of the detector, significantly improving the performance of the mercury cadmium telluride infrared detector.

[0004] This application provides a method for fabricating a photonic crystal structure on the surface of a mercury cadmium telluride infrared detector, including:

[0005] A photoresist of a predetermined thickness is coated on the surface of the mercury cadmium telluride chip;

[0006] The cadmium zinc telluride substrate of the mercury cadmium telluride chip that needs to be removed is exposed and developed using photolithography equipment to expose that area.

[0007] Remove the exposed cadmium zinc telluride substrate portion;

[0008] Remove photoresist;

[0009] Recoat the surface of the mercury cadmium telluride chip with a specified thickness of photoresist;

[0010] The pattern of a photonic crystal is transferred from a photomask to the surface of an infrared detector chip using photomask exposure and development.

[0011] The zinc-cadmium telluride (CdC) substrate is etched using a zinc-cadmium telluride etchant to remove the CdC telluride substrate of a specified thickness, and then dry etching of the photonic crystal pattern is performed.

[0012] Optionally, the thickness of the photoresist coated on the surface of the mercury cadmium telluride chip is comparable to the reserved thickness of the cadmium zinc telluride chip.

[0013] Optionally, the exposed cadmium zinc telluride substrate may be partially removed so that the remaining cadmium zinc telluride substrate thickness is comparable to the photoresist film thickness.

[0014] Optionally, after performing dry etching of the photonic crystal pattern, the following may also be included:

[0015] Remove photoresist;

[0016] The photonic crystal structure formed by the etching and etching process is modified using zinc-cadmium telluride etching solution to complete the structure processing.

[0017] This application also proposes a mercury cadmium telluride infrared detector chip, including a readout circuit, a mercury cadmium telluride chip, and a mercury cadmium telluride substrate.

[0018] The mercury cadmium telluride chip is flip-mounted on the readout circuit;

[0019] The mercury cadmium telluride substrate is disposed on the opposite side of the mercury cadmium telluride chip and the readout circuit;

[0020] A photonic crystal structure is fabricated on the mercury cadmium telluride substrate based on the aforementioned method for fabricating a photonic crystal structure on the surface of a mercury cadmium telluride infrared detector.

[0021] This application also proposes an infrared detector, including the aforementioned mercury cadmium telluride infrared detector chip.

[0022] The method in this application embodiment can fabricate a photonic crystal structure on the surface of a mercury cadmium telluride infrared detector using a high-design-fit processing method, replacing the original antireflection film structure. This achieves efficient antireflection across the entire spectral response range of the detector, significantly improving the performance of the mercury cadmium telluride infrared detector.

[0023] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0024] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0025] Figure 1This is an example of the state after coating with photoresist of a predetermined thickness in the photonic crystal structure processing method of this application embodiment;

[0026] Figure 2 This is an example of the exposure state of the photonic crystal structure fabrication method according to an embodiment of this application;

[0027] Figure 3 This is an example of the exposed cadmium zinc telluride substrate state in the photonic crystal structure fabrication method of this application embodiment;

[0028] Figure 4 This is an example of the state of removing the bare zinc-cadmium telluride substrate using a photonic crystal structure processing method according to an embodiment of this application;

[0029] Figure 5 This is an example of the photoresist removal state in the photonic crystal structure fabrication method of this application embodiment;

[0030] Figure 6 This is an example of the state after re-spraying and developing in the photonic crystal structure processing method of this application embodiment;

[0031] Figure 7 This is an example of the state after etching with cadmium zinc telluride solution in the photonic crystal structure fabrication method of this application embodiment;

[0032] Figure 8 This is an example of IPC ion etching, a method for fabricating photonic crystal structures, as described in this application.

[0033] Figure 9 This is an example of the photoresist removal state after IPC ion etching in the photonic crystal structure processing method of this application embodiment;

[0034] Figure 10 This is an example of etching process using an etchant in a photonic crystal structure fabrication method according to an embodiment of this application.

[0035] Figure 11 This is an example of a photonic crystal structure obtained by the photonic crystal structure processing method according to an embodiment of this application;

[0036] Figure 12 The transmittance curves of the photonic crystal structure in the embodiment of this application are within the spectral response range of the mercury cadmium telluride infrared detector. Detailed Implementation

[0037] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0038] This application provides a method for fabricating a photonic crystal structure on the surface of a mercury cadmium telluride infrared detector, such as... Figures 1-8 As shown, it includes the following steps:

[0039] A photoresist 4 of a predetermined thickness is coated on the surface of the mercury cadmium telluride (HCd) chip 2. In some embodiments, the HCd chip 2 is connected to the readout circuit 1, and the thickness of the photoresist coated on the surface of the HCd chip 2 is approximately equal to the reserved thickness of the cadmium zinc telluride (CZD) substrate 3. For example, a photoresist spraying device can be used to coat the surface of the HCd infrared detector with a photoresist thickness approximately equal to the final remaining thickness of the HCd chip.

[0040] Then, photolithography equipment is used to expose and develop a portion of the cadmium zinc telluride substrate that needs to be removed from the mercury cadmium telluride chip, thereby exposing that portion. Specifically, as follows... Figure 2 As shown, the exposure light 6 is exposed through the mask 5, as... Figure 3 The diagram shows at least a portion of the exposed cadmium zinc telluride substrate.

[0041] Remove the exposed cadmium zinc telluride substrate portion, such as Figure 4 As shown. Specifically, polishing equipment can be used to remove the exposed mercury cadmium telluride chips.

[0042] Remove photoresist, such as Figure 5 As shown.

[0043] Recoat the surface of the mercury cadmium telluride chip with a specified thickness of photoresist, such as... Figure 6 As shown.

[0044] The pattern of a photonic crystal is transferred from a photomask to the surface of an infrared detector chip using mask exposure and development.

[0045] The zinc-cadmium telluride substrate was etched using a zinc-cadmium telluride etchant, such as... Figure 7 As shown, a cadmium zinc telluride substrate of a specified thickness is removed, and dry etching of the photonic crystal pattern is performed, as follows. Figure 8 As shown. Specifically, after chip cleaning, the photonic crystal pattern can be transferred to the surface of the mercury cadmium telluride (MCH) chip using photolithography. A zinc cadmium telluride (CdC) etchant is then used to etch the CdC substrate to a certain depth. Then, inductively coupled plasma (ICP) etching is used to continue dry etching of the photonic crystal pattern.

[0046] The method in this application embodiment can fabricate a photonic crystal structure on the surface of a mercury cadmium telluride infrared detector using a high-design-fit processing method, replacing the original antireflection film structure. This achieves efficient antireflection across the entire spectral response range of the detector, significantly improving the performance of the mercury cadmium telluride infrared detector.

[0047] In some embodiments, the exposed cadmium zinc telluride (CZN) substrate is partially removed so that the remaining CZN substrate thickness is comparable to the photoresist film thickness. Due to the support of the photoresist on the chip surface, the remaining thickness of the CZN substrate is comparable to the photoresist thickness, thereby achieving precise control over the CZN substrate thickness.

[0048] In some embodiments, after performing dry etching of the photonic crystal pattern, the method further includes:

[0049] Remove photoresist, such as Figure 9 As shown.

[0050] The photonic crystal structure formed by etching and etching processes using zinc-cadmium telluride etchant is reshaped to complete the structural fabrication, such as... Figure 10 As shown. The photonic crystal structure fabrication method of this application combines the lateral etching effect of wet etching with the better steepness of dry etching patterns, ultimately obtaining a smooth photonic crystal structure with a certain tilt angle, as shown. Figure 11 As shown.

[0051] like Figure 12 As shown, the method of this application achieves efficient anti-reflection across the entire spectral response range of the detector, thus significantly improving the performance of the mercury cadmium telluride infrared detector. Specifically, the method of this application uses a photonic crystal structure to replace the anti-reflection film on the surface of the mercury cadmium telluride infrared detector, achieving high anti-reflection across the entire spectral response range of the infrared detector and improving its performance.

[0052] This application also proposes a mercury cadmium telluride infrared detector chip, including a readout circuit, a mercury cadmium telluride chip, and a mercury cadmium telluride substrate.

[0053] The mercury cadmium telluride chip is flip-mounted on the readout circuit;

[0054] The mercury cadmium telluride substrate is disposed on the opposite side of the mercury cadmium telluride chip and the readout circuit;

[0055] A photonic crystal structure is fabricated on the mercury cadmium telluride substrate based on the aforementioned method for fabricating a photonic crystal structure on the surface of a mercury cadmium telluride infrared detector.

[0056] This application also proposes an infrared detector, including the aforementioned mercury cadmium telluride infrared detector chip.

[0057] The method in this application embodiment can fabricate a photonic crystal structure on the surface of a mercury cadmium telluride infrared detector using a high-design-fit processing method, replacing the original antireflection film structure. This achieves efficient antireflection across the entire spectral response range of the detector, significantly improving the performance of the mercury cadmium telluride infrared detector.

[0058] It should be noted that, in the embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0059] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0060] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0061] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims. All of these forms are within the protection scope of this application.

Claims

1. A method for fabricating a photonic crystal structure on the surface of a mercury cadmium telluride infrared detector, characterized in that, include: A photoresist of a predetermined thickness is coated on the surface of a mercury cadmium telluride chip, wherein the mercury cadmium telluride chip is flip-chip mounted on a readout circuit, and the thickness of the photoresist coated on the surface of the mercury cadmium telluride chip is equivalent to the reserved thickness of the cadmium zinc telluride substrate. The cadmium zinc telluride substrate of the mercury cadmium telluride chip that needs to be removed is exposed and developed using photolithography equipment to expose that area. The exposed cadmium zinc telluride substrate is partially removed so that the remaining cadmium zinc telluride substrate thickness is comparable to the photoresist film thickness. Remove photoresist; Recoat the surface of the mercury cadmium telluride chip with a specified thickness of photoresist; The pattern of a photonic crystal is transferred from a photomask to the surface of an infrared detector chip using photomask exposure and development. The zinc-cadmium telluride substrate is etched using a zinc-cadmium telluride etchant to remove a specified thickness of the substrate, and a dry etching process is performed to pattern the photonic crystal. The zinc-cadmium telluride substrate is located on the opposite side of the mercury cadmium telluride chip from the readout circuit.

2. The method for fabricating a photonic crystal structure on the surface of a mercury cadmium telluride infrared detector as described in claim 1, characterized in that, After performing dry etching of the photonic crystal pattern, the following steps are also included: Remove photoresist; The photonic crystal structure formed by the etching and etching process is modified using zinc-cadmium telluride etching solution to complete the structure processing.

3. A mercury cadmium telluride infrared detection chip, characterized in that, This includes readout circuitry, mercury cadmium telluride (HCd) chips, and cadmium zinc telluride (CdZn) substrates. The mercury cadmium telluride chip is flip-mounted on the readout circuit; The zinc cadmium telluride substrate is disposed on the opposite side of the mercury cadmium telluride chip and the readout circuit; A photonic crystal structure is fabricated on the zinc cadmium telluride substrate based on the photonic crystal structure fabrication method for the surface of the mercury cadmium telluride infrared detector as described in claim 1 or 2.

4. An infrared detector, characterized in that, Including the mercury cadmium telluride infrared detection chip as described in claim 3.

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