A method of mounting an infrared detector cold shield component

Abstract

This invention proposes a method for installing a cold screen component for an infrared detector, comprising: preparing crosshairs on the top of an electroformed cold screen; bonding a filter to the opening of the cold screen and baking it until the adhesive cures; placing a Dewar semi-finished product with the infrared detector chip mounted on it under a microscope, adjusting the positioning marks on the infrared detector chip to completely coincide with the crosshairs of the microscope, and fixing the current position of the Dewar semi-finished product; placing the current cold screen at the installation station, adjusting the crosshairs under the microscope to completely coincide with the crosshairs of the microscope; bonding and fixing the cold screen component, and baking it in an oven after pre-curing. The method provided by this invention simplifies the packaging process of infrared detector components and significantly improves the packaging efficiency, cold screen installation accuracy, foreign matter control, and component rework costs.

Description

Technical Field

[0001] This invention relates to the field of infrared equipment manufacturing technology, and in particular to a method for installing a cold screen component of an infrared detector. Background Technology

[0002] With the continuous maturation of infrared photoelectric detection technology, cooled infrared focal plane detectors are widely used in various fields such as civil security systems, climate and meteorological information collection, astronomical research, fire early warning, and safety production monitoring. The demand for cooled infrared focal plane detectors in domestic and international markets is growing day by day, which puts forward higher requirements for the production capacity and product quality of infrared detector component suppliers.

[0003] The infrared detector Dewar is a key component that carries the infrared detector chip, providing a stable environment for its normal operation. The Dewar assembly involves various materials, including metals, ceramics, semiconductors, and organic polymers. Its fabrication process employs multiple techniques such as low-temperature brazing, high-temperature brazing, laser welding, resistance welding, electron beam welding, wire bonding, and high-strength bonding, resulting in a relatively long production cycle. Assuming a sufficient number of qualified chips, the Dewar assembly's packaging cycle directly determines the product's delivery capability. Currently, the cold screen mounting and filter mounting processes within the Dewar account for a significant portion of the production cycle. This is primarily because existing designs require the cold screen to be positioned and bonded under a microscope, and the filter can only be bonded to the cold screen opening after the adhesive has cured for a day. This sequential process wastes time waiting for the adhesive to cure. Therefore, it is necessary to optimize the cold screen design and improve the cold screen and filter mounting processes to shorten the assembly packaging cycle and increase packaging efficiency and production capacity.

[0004] Currently, the installation process for the cold screen and filter is a sequential assembly. First, the pre-assembled Dewar shaped device with the chip is fixed under a tooling microscope. The positioning marks on the chip are aligned perfectly with the crosshairs of the tooling microscope. The position of the Dewar shaped device is then fixed, and the cold screen is placed in its mounting position. Under the tooling microscope, the center of the cold screen's opening is aligned with the center of the crosshairs (this adjustment calculation process is tedious and inefficient for operators). The cold screen is then bonded to the Dewar shaped device with adhesive. After the adhesive has pre-cured, the device is transferred to an oven for baking and curing. The Dewar shaped device with the cold screen bonded is then placed under a microscope for filter bonding. After the filter is bonded, it also needs to be baked and cured before subsequent processes can proceed. The curing time for the filter and cold screen bonding has the potential to be reduced, but the reliability of the cold screen bonding and the horizontal and vertical installation accuracy with the chip's photosensitive area must be ensured. Summary of the Invention

[0005] The technical problem this invention aims to solve is how to ensure installation accuracy and shorten the process flow. In view of this, this invention provides an installation method for a cold shield component of an infrared detector.

[0006] The technical solution adopted in this invention is a method for installing the cold shield component of the infrared detector, comprising:

[0007] Step S1: Prepare the cold screen cross lines on the top of the electroformed cold screen;

[0008] Step S2: Adhere the filter to the opening of the cold screen and bake until the adhesive cures;

[0009] Step S3: Place the Dewar semi-finished product with the infrared detector chip attached under a microscope, adjust the positioning mark on the infrared detector chip to completely coincide with the crosshairs of the microscope, and fix the current position of the Dewar semi-finished product.

[0010] Step S4: Place the current cold screen at the installation station and adjust the crosshairs under the microscope so that the crosshairs are completely aligned with the crosshairs of the microscope.

[0011] Step S5: The cold screen is bonded and fixed, and after pre-curing, it is placed in an oven for baking and curing.

[0012] In one embodiment, step S1 includes:

[0013] The cross-shaped lines are prepared using an ultrafast laser precision scribing device, wherein the width of the cross-shaped lines is between 50 μm and 80 μm, and the scribing depth is between 50 μm and 80 μm.

[0014] In one embodiment, the method further includes:

[0015] The accuracy of the cross-shaped markings is checked.

[0016] By adopting the above technical solution, the installation method of the infrared detector cold shield component provided by the present invention has at least the following advantages:

[0017] The method provided by this invention can simplify the packaging process of infrared detector components. It changes the original serial process of installing the cold screen first and then the filter to assembling the filter and cold screen in advance, shortening the main process of infrared detector component packaging. It has a significant improvement in many aspects such as infrared detector component packaging efficiency, cold screen installation accuracy, foreign matter control, and component rework cost.

[0018] Furthermore, the method provided by this invention can ensure the horizontal and vertical installation accuracy of the cold screen opening installed using the etched line relative to the center of the chip's photosensitive area. Attached Figure Description

[0019] Figure 1 A flowchart illustrating the installation method of the cold shield component of an infrared detector according to an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of high-precision cold screen mounting markings according to an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of a high-precision cold screen engraving according to an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram illustrating the installation of a cold screen using high-precision markings according to an embodiment of the present invention;

[0023] Figure 5 This is a comparison of the embodiments of the present invention with the cold screen installation process in the prior art. Detailed Implementation

[0024] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

[0025] In the accompanying drawings, the thickness, size, and shape of the objects have been slightly exaggerated for ease of illustration. The drawings are for illustrative purposes only and are not drawn to scale.

[0026] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed feature, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0027] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] The steps described in the specification and the flowcharts in the accompanying drawings of this invention are not necessarily to be strictly followed according to the step numbers; the execution order of the steps can be changed. Furthermore, certain steps can be omitted, multiple steps can be combined into one step, and / or one step can be broken down into multiple steps.

[0030] In the first embodiment of the present invention, a method for installing a cold shield component of an infrared detector is provided, as follows: Figure 1 As shown, the specific steps include the following:

[0031] Step S1: Prepare the cold screen cross lines on the top of the electroformed cold screen;

[0032] Step S2: Attach the filter to the opening of the cold screen and bake until the adhesive cures.

[0033] Step S3: Place the Dewar semi-finished product with the infrared detector chip attached under a microscope, adjust the positioning mark on the infrared detector chip to completely coincide with the crosshairs of the microscope, and fix the current position of the Dewar semi-finished product.

[0034] Step S4: Place the current cold screen at the installation station and adjust the crosshairs under the microscope so that the crosshairs are completely aligned with the crosshairs of the microscope.

[0035] Step S5: Bond and fix the cold screen components, and place them in an oven for baking and curing after pre-curing.

[0036] Specifically, the cross-shaped lines are prepared using an ultrafast laser precision scribing device, wherein the width of the cross-shaped lines is between 50 μm and 80 μm, and the scribing depth is between 50 μm and 80 μm.

[0037] In this embodiment, the accuracy of the cross-shaped markings can also be checked.

[0038] The second embodiment of the present invention, with reference to Figures 2 to 5 This embodiment is an application example based on the first embodiment, and specifically includes the following steps:

[0039] In this embodiment, reference Figure 4 It involves infrared detector chip 1, cold screen 2, cold screen cross lines 3, and filter 4;

[0040] 1) Using an ultrafast laser precision scribing device, cross-shaped scribing lines 3 are prepared on the electroformed cold screen 2. The scribing line width is between 50μm and 80μm, and the scribing line depth is between 50μm and 80μm.

[0041] 2) Inspect the scribing accuracy of the cold-screen parts to ensure they meet design requirements before proceeding with subsequent processes;

[0042] 3) Batch processing: Adhere the filter 4 to the opening of the cold screen 2 and bake until the adhesive is cured;

[0043] 4) Place the Dewar semi-finished product with the chip attached under the tool microscope, adjust the positioning mark on the infrared detector chip 1 to completely coincide with the crosshairs of the tool microscope, and fix the position of the Dewar semi-finished product.

[0044] 5) Place the cold screen 2 component with the filter glued on in its installation position, and adjust the crosshair 3 on the top of the cold screen under the tool microscope so that the two perpendicular lines are completely aligned with the crosshair of the tool microscope.

[0045] 6) Use adhesive to bond and fix the cold screen components, and after pre-curing, place them in an oven for baking and curing;

[0046] Specifically, the pre-curing step mentioned above can refer to the process of waiting for the adhesive to solidify.

[0047] This invention uses an ultrafast laser combined with a visual recognition system and special tooling to prepare cold screen etched lines. However, the method for preparing etched lines is not limited to this method. The etched line width and depth designed in this invention are within 50μm-80μm, but are not limited to this size and can be changed according to product requirements.

[0048] In summary, compared with the prior art, the method provided in this embodiment has at least the following advantages:

[0049] 1) This embodiment can simplify the packaging process of infrared detector components. The original serial process of installing the cold screen first and then the filter is changed to assembling the filter and cold screen in advance, which shortens the main process of infrared detector component packaging. In this way, the packaging cycle of infrared detector components can be shortened by 1 working day, which greatly promotes the efficiency and production capacity of infrared detector packaging.

[0050] 2) This design method can ensure that the horizontal and vertical installation accuracy of the cold screen opening installed using this etched line relative to the center of the chip's photosensitive area is within ±20μm. This indicator cannot be measured in practice with previous installation methods.

[0051] 3) In some existing technologies, a cold screen needs to be installed first and left for a period of time to allow the adhesive to cure. During this process, there may be foreign objects falling into the cold screen and they cannot be effectively observed and cleaned, which affects the yield of the finished product after the component is packaged. However, in the embodiment of this application, the cold screen and the filter are assembled first and then installed on the cold head structure of the infrared detector. The chip and cold screen components can be thoroughly cleaned before the cold screen is installed, which further suppresses the occurrence of foreign object failure.

[0052] 4) In this embodiment, the cold screen and the filter are integrated components with positioning marks, which allows the original cold screen component to be reused when the infrared detector assembly is repaired. In contrast, the old method required replacing the cold screen and filter to ensure the installation accuracy of the cold screen. This greatly improves the repair efficiency of the assembly and reduces the repair cost.

[0053] Based on the above description of the advantages of the present invention, it is fully demonstrated that the present invention has greatly improved the packaging efficiency of infrared detector components, cold screen installation accuracy, foreign object control, component rework cost, and other aspects, and solved the key technical problems in the packaging process of infrared detector components, which is of great significance to the advancement of infrared detector packaging technology.

[0054] Through the description of specific embodiments, a more in-depth and specific understanding should be gained of the technical means and effects adopted by the present invention to achieve the intended purpose. However, the accompanying drawings are only provided for reference and illustration and are not intended to limit the present invention.

Claims

1. A method for installing a cold shield component of an infrared detector, characterized in that, include: Step S1: Prepare the cold screen cross lines on the top of the electroformed cold screen; Step S2: Adhere the filter to the opening of the cold screen and bake until the adhesive cures; Step S3: Place the Dewar semi-finished product with the infrared detector chip attached under a microscope, adjust the positioning mark on the infrared detector chip to completely coincide with the crosshairs of the microscope, and fix the current position of the Dewar semi-finished product. Step S4: Place the current cold screen at the installation station and adjust the crosshairs under the microscope so that the crosshairs are completely aligned with the crosshairs of the microscope. Step S5: The cold screen is bonded and fixed, and after pre-curing, it is placed in an oven for baking and curing.

2. The method for installing the cold shield component of the infrared detector according to claim 1, characterized in that, Step S1 includes: The cross-shaped lines are prepared using an ultrafast laser precision scribing device, wherein the width of the cross-shaped lines is between 50 μm and 80 μm, and the scribing depth is between 50 μm and 80 μm.

3. The method for installing the infrared detector cold shield component according to claim 1, characterized in that, The method further includes: The accuracy of the cross-shaped markings is checked.

Images