Infrared detector responsivity non-uniformity correction method and system
By preparing microlens structures and metal light-shielding structures on the pixel surface of the infrared detector, adjusting the signal response, solving the problem of response rate inhomogeneity and improving the imaging quality and application range.
Patent Information
- Application Number
- CN202411611961.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2025-02-28
AI Technical Summary
The nonuniformity of the response rate of mercury cadmium telluride infrared detectors will affect the imaging quality and limit their application range.
By preparing a microlens structure on the pixel surface where signal enhancement is required, and a metal light-shielding structure is prepared at the edges of pixels where signal is needed to be reduced, the pixel signal response size is adjusted, and the response rate non-uniformity correction is performed.
It effectively improves the imaging quality of infrared detectors and expands its application range.
Smart Images
Figure CN119533679A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor technology, and in particular to a method and system for correcting non-uniformity of response rate of an infrared detector. Background Art
[0002] Infrared focal plane detection technology has significant advantages such as wide spectral response band, more ground target information, and day and night operation. It is widely used in agriculture, animal husbandry, forest resource survey, development and management, weather forecast, geothermal distribution, earthquake, volcanic activity, space astronomical detection and other fields. The non-uniformity of the response rate of mercury cadmium telluride infrared detector is one of the important technical indicators of infrared detection, which directly affects the infrared detector's ability to detect targets.
[0003] Mercury cadmium telluride infrared detector is one of the representative products of infrared detection technology, such as Figure 1 As shown in the figure, it is made of infrared photosensitive materials (mercury cadmium telluride chip) and silicon-based readout circuits through inverted interconnection of equipment. Its working principle is: the mercury cadmium telluride chip receives the infrared radiation of the target, causing electron transitions inside the chip to generate photogenerated electrons and photogenerated holes to form a weak current, and then the readout circuit reads this weak current and converts it into a voltage signal output. Affected by the growth of mercury cadmium telluride materials and the device preparation process, different pixels of the infrared detector generate different signals for infrared radiation of the same intensity, so the non-uniformity of the response rate will affect the imaging quality. Figure 2 The non-uniformity of the response rate of the infrared detector is very poor, which limits the application range of the infrared detector. Therefore, it is necessary to correct the non-uniformity of the response rate of the infrared detector, which is a key technical issue to improve the performance of the infrared detector. Summary of the invention
[0004] The embodiments of the present application provide a method and system for correcting the non-uniformity of the response rate of an infrared detector, which enables the preparation of a microlens structure on the surface of a pixel where signal enhancement is required to enhance the signal, and the preparation of a metal shading structure on the edge of a pixel where the signal needs to be reduced. By adjusting the pixel signal response size, the non-uniformity of the response rate of the infrared detector is corrected to improve its performance.
[0005] The present application provides a method for correcting non-uniformity of infrared detector response rate, including:
[0006] Get infrared detector test level data;
[0007] Calculate the optimal value interval of the infrared detector signal response based on the infrared detector test level data; and
[0008] generating a coefficient matrix corresponding to the pixel positions of the infrared detector;
[0009] According to the calculated optimal value interval and the coefficient matrix, negative coefficients are configured for pixels that need to reduce the response, and positive coefficients are configured for pixels that need to increase the response, wherein the more the response is reduced, the greater the absolute value of the negative coefficient is;
[0010] The photolithography pattern design is performed according to the configured coefficient matrix.
[0011] Optionally, according to the calculated optimal value interval and the coefficient matrix, the method further includes: configuring coefficients of 0 for pixels that do not require correction.
[0012] Optionally, performing lithography pattern design according to the configured coefficient matrix includes:
[0013] A pixel edge shading structure is provided for negative coefficients, and a pixel-aligned microlens structure is provided for positive coefficients.
[0014] Optionally, a pixel edge shading structure is set for a negative coefficient, wherein the greater the absolute value of the negative coefficient is, the greater the size of the shading structure is; and,
[0015] A pixel-aligned microlens structure set for a positive coefficient, wherein the larger the positive coefficient, the larger the size of the microlens structure.
[0016] Optionally, the pixel edge shading structure set for the negative coefficient includes:
[0017] At the edge of the pixel, a shading structure is set according to the size of the negative coefficient, and the remaining area of the pixel is in the middle;
[0018] Microlens structures with pixel alignment for positive coefficients include:
[0019] A microlens structure is set at the middle position of the pixel according to the size of the positive coefficient.
[0020] The embodiment of the present application also proposes an infrared detector response rate non-uniformity correction system, including a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the infrared detector response rate non-uniformity correction method as described above are implemented.
[0021] The embodiments of the present application can realize signal enhancement by preparing a microlens structure on the surface of pixels where signal enhancement is required, and prepare a metal shading structure at the edge of pixels where signal reduction is required. By adjusting the pixel signal response size, the non-uniformity of the response rate of the infrared detector is corrected to improve its performance.
[0022] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:
[0024] Figure 1 The figure is a schematic diagram of a mercury cadmium telluride infrared detector in the prior art;
[0025] Figure 2 It is a schematic diagram of the level response of an infrared detector with poor non-uniformity of response rate in the prior art to uniform radiation;
[0026] Figure 3 The basic process diagram of the infrared detector response rate non-uniformity correction method according to the embodiment of the present application is shown;
[0027] Figure 4 3×3 pixels are schematically shown for the infrared detector response rate non-uniformity correction method according to an embodiment of the present application;
[0028] Figure 5 A schematic diagram of a 3×3 pixel light shielding structure of the infrared detector response rate non-uniformity correction method according to an embodiment of the present application;
[0029] Figure 6 A schematic diagram of a 3×3 pixel microlens structure of an infrared detector response rate non-uniformity correction method according to an embodiment of the present application;
[0030] Figure 7 The application example of this application is to transfer microlens patterns on the surface of pixels that need signal enhancement;
[0031] Figure 8 Schematic diagram of the microlens structure etched by inductively coupled plasma etching in the application example of this application;
[0032] Fig. 9 The application example of this application requires a pixel surface with enhanced signal to complete the microlens signal enhancement structure preparation diagram;
[0033] Fig.10 The application example of this application is a schematic diagram of a metal film layer grown on the detector surface for preparing a light shielding structure;
[0034] Fig.11The application example of this application is to transfer the shading structure pattern on the pixel surface where the signal needs to be weakened;
[0035] Fig.12 The application example of this application uses a plasma etching method to remove the metal film layer in the light-transmitting area;
[0036] Fig.13 The application example of this application completes the schematic diagram of the preparation of the response rate non-uniformity correction structure. DETAILED DESCRIPTION
[0037] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.
[0038] The present application embodiment provides a method for correcting the non-uniformity of the response rate of an infrared detector, such as Figure 3 As shown, the following steps are included:
[0039] In step S101, infrared detector test level data is obtained.
[0040] The infrared detector test level data is analyzed. In step S102, the optimal value interval of the infrared detector signal response is calculated based on the infrared detector test level data.
[0041] In step S103, a coefficient matrix corresponding to the pixel positions of the infrared detectors is generated, that is, the positions of the infrared detector array and the matrix correspond to each other.
[0042] In step S104, based on the calculated optimal value interval and the coefficient matrix, negative coefficients are configured for pixels that need to reduce the response, and positive coefficients are configured for pixels that need to increase the response, wherein the more the response is reduced, the larger the absolute value of the negative coefficient is; pixels that need to increase the signal response are defined as positive coefficients, and the more the increase is, the larger the coefficient is.
[0043] In step S105, the photolithography pattern design is performed according to the configured coefficient matrix. In some specific examples, the photolithography pattern design can be performed according to the coefficient matrix using design software.
[0044] In some embodiments, according to the calculated optimal value interval and the coefficient matrix, the method further includes: configuring coefficients of pixels that do not require correction to be 0.
[0045] In some embodiments, performing lithography pattern design according to the configured coefficient matrix includes:
[0046] A pixel edge shading structure is provided for negative coefficients, and a pixel-aligned microlens structure is provided for positive coefficients.
[0047] In some embodiments, Figure 4 is a 3×3 pixel array structure, and is a pixel edge shading structure set by a negative coefficient, wherein the structure size is related to the coefficient, and the larger the absolute value of the negative coefficient, the larger the size of the shading structure. Figure 5 Shown is a 3×3 pixel array, with shading structures of different sizes prepared at the edge according to the negative coefficient value.
[0048] A pixel-aligned microlens structure set for a positive coefficient, where the structure size is related to the coefficient, and the larger the positive coefficient, the larger the size of the microlens structure. Figure 6 As shown, it is a 3×3 pixel array, and microlens structures of different sizes are prepared in the center according to the coefficient value.
[0049] In some embodiments, the pixel edge shading structure set for the negative coefficient includes:
[0050] At the edge of the pixel, a shading structure is set according to the size of the negative coefficient, and the remaining area of the pixel is in the middle;
[0051] Microlens structures with pixel alignment for positive coefficients include:
[0052] At the middle position of the pixel, set the microlens structure according to the size of the positive coefficient. For details, see Figure 5 , Figure 6 shown.
[0053] The present application also provides an example of device preparation using the infrared detector response rate non-uniformity correction method of the present application, including the following steps:
[0054] First, the software is used to complete the graphic design of each pixel according to the coefficient matrix, and the pixel array is arranged to add the alignment mark pattern corresponding to the detector to generate a photolithography graphic file. The designed microlens pattern is first transferred to the detector surface that needs to be corrected for response rate non-uniformity using a photolithography device, and the corresponding microlens structure is etched using an inductively coupled plasma etching device. Then, a metal coating device is used to perform metal coating (Cr: 50nm, Au: 100nm) on the detector surface, and the designed light-shielding structure is transferred to the detector surface using a photolithography device again, and finally a plasma etching device is used to remove the metal in the pixel light-transmitting area.
[0055] Specifically include:
[0056] Step 1: Transferring the microlens pattern on the pixel surface where signal enhancement is required;
[0057] Step 2: Inductively coupled plasma etching of microlens structure;
[0058] Step 3: growing a metal film layer for preparing a light-shielding structure on the surface of the detector;
[0059] Step 4: Use plasma etching method to remove the metal film layer in the light-transmitting area.
[0060] like Figure 7-Figure 13 As shown, Figure 7 The transfer of a microlens pattern on a pixel surface where signal enhancement is desired is shown.
[0061] Figure 8 A schematic diagram of the inductively coupled plasma etched microlens structure is shown.
[0062] Fig. 9 The schematic diagram of preparing the microlens signal enhancement structure for the pixel surface requiring signal enhancement is shown.
[0063] Fig.10 A schematic diagram of a metal film layer grown on the detector surface for preparing a light-shielding structure is shown.
[0064] Fig.11 The diagram shows a schematic diagram of transferring the light shielding structure pattern on the pixel surface where signal attenuation is required.
[0065] Fig.12 The schematic diagram shows the use of plasma etching method to remove the metal film layer in the light-transmitting area.
[0066] Fig.13 A schematic diagram of the preparation of a response rate non-uniformity correction structure is shown.
[0067] The embodiments of the present application can realize signal enhancement by preparing a microlens structure on the surface of pixels where signal enhancement is required, and prepare a metal shading structure at the edge of pixels where signal reduction is required. By adjusting the pixel signal response size, the non-uniformity of the response rate of the infrared detector is corrected to improve its performance.
[0068] The embodiment of the present application also proposes an infrared detector response rate non-uniformity correction system, including a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the infrared detector response rate non-uniformity correction method as described above are implemented.
[0069] It should be noted that in the various embodiments of the present application, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.
[0070] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.
[0071] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.
[0072] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.
Claims
1. A method for correcting non-uniformity of infrared detector response rate, characterized in that: include: Get infrared detector test level data; The optimal value interval of the infrared detector signal response is calculated based on the infrared detector test level data; as well as, generating a coefficient matrix corresponding to the pixel positions of the infrared detector; According to the calculated optimal value interval and the coefficient matrix, negative coefficients are configured for pixels that need to reduce the response, and positive coefficients are configured for pixels that need to increase the response, wherein the more the response is reduced, the greater the absolute value of the negative coefficient is; The photolithography pattern design is performed according to the configured coefficient matrix.
2. The infrared detector response rate non-uniformity correction method according to claim 1, characterized in that: According to the calculated optimal value interval and the coefficient matrix, it also includes: configuring coefficients of 0 for pixels that do not need to be corrected.
3. The infrared detector response rate non-uniformity correction method according to claim 1, characterized in that: The lithography pattern design according to the configured coefficient matrix includes: A pixel edge shading structure is provided for negative coefficients, and a pixel-aligned microlens structure is provided for positive coefficients.
4. The infrared detector response rate non-uniformity correction method according to claim 3, characterized in that: A pixel edge shading structure set for a negative coefficient, wherein the greater the absolute value of the negative coefficient, the greater the size of the shading structure; and, A pixel-aligned microlens structure set for a positive coefficient, wherein the larger the positive coefficient, the larger the size of the microlens structure.
5. The infrared detector response rate non-uniformity correction method according to claim 4, characterized in that: The pixel edge shading structure set for negative coefficients includes: At the edge of the pixel, a shading structure is set according to the size of the negative coefficient, and the remaining area of the pixel is in the middle; Microlens structures with pixel alignment for positive coefficients include: A microlens structure is set at the middle position of the pixel according to the size of the positive coefficient.
6. An infrared detector response rate non-uniformity correction system, characterized in that: The method comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the steps of the infrared detector response rate non-uniformity correction method as claimed in any one of claims 1 to 5 are implemented.