Dewar heating and outgassing apparatus and method

Abstract

The application discloses a Dewar heating and degassing device and a degassing method, which comprises a degassing furnace cavity, an optical fiber penetrating through the side wall of the cavity, a water-cooling pipe spirally wound on the periphery of the optical fiber, one end of the optical fiber outside the cavity being connected with a laser, and a supporting component for fixing degassing parts in the degassing furnace cavity, wherein the supporting component is provided with a base plate, a rotating shaft for driving the base plate to move horizontally or rotate, and a lifting component for driving the base plate to move vertically. The application can degas different heat-resistant parts in the same batch, and greatly improves the degassing efficiency of the degassing furnace on the parts. Through the partition heating method, the degassing effect of a single part is greatly improved, and is not affected by the heat resistance of other model parts in the same batch.

Description

Technical Field

[0001] This invention relates to the field of infrared detector packaging technology, and in particular to a Dewar heating degassing device and degassing method. Background Technology

[0002] An infrared detector mainly consists of three parts: a chip, a Dewar assemblies, and a cooler. The Dewar assemblies of an infrared detector provide a vacuum operating environment for the chip. Vacuum life is a crucial reliability indicator for the Dewar assemblies of an infrared detector. Material outgassing is a major factor affecting vacuum life. To reduce the rate and amount of outgassing into the Dewar cavity after encapsulation, the components need to be heated and baked during the encapsulation process to remove gas. Heating degassing allows for the desorption of partially adsorbed gases on the material surface and the precipitation of atoms of the constituent gases within the material.

[0003] Currently, all heating and degassing methods involve heating the entire material. Because multiple components, or even a single component, contain materials with various heat-resistant properties, the degassing process must be designed with the lowest heat-resistant material at the highest degassing temperature. Therefore, the more heat-resistant materials on the components are not adequately degassed. Furthermore, for components made of different materials and at different packaging stages, multiple degassing processes at different temperatures are required to ensure low gas uptake in the final packaging step. These traditional component heating and degassing methods significantly impact the overall packaging efficiency of the Dewar assemblies. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a Dewar heating degassing device, comprising: Degassing furnace cavity; Optical fiber penetrating the sidewall of the cavity; A water-cooling pipe spirally wound around the outer edge of the optical fiber; A laser is connected to one end of the optical fiber outside the cavity. A support component located inside the gas furnace cavity for fixing the degassing parts, the support component having a chassis, a rotating shaft for driving the chassis to move horizontally or rotate, and a lifting component for driving the chassis to move vertically.

[0005] Optionally, a mask device is also included, which is located closest to the degassing component and is made of opaque metal or glass with a certain light transmittance.

[0006] Optionally, it also includes a beam splitter assembly, which is installed inside the degassing furnace and located near the optical fiber. After the beam splitter scatters the light, it obtains multiple beams of light with the same or different preset energies.

[0007] Optionally, it also includes a laser head, which is disposed inside the degassing furnace, located closest to the optical fiber or between the beam splitter group and the degassing components. The laser head includes one or more conical lenses or cylindrical mirrors for receiving the emitted laser and adjusting the shape of the laser to determine whether the emitted laser is point-shaped, ring-shaped, line-shaped or area-shaped.

[0008] Optionally, it may also include one or more galvanometers, which are disposed on the XYZ movable platform and located between the laser head and the mask device or between the laser head and the degassing component.

[0009] Optionally, the laser operates in pulse irradiation or continuous irradiation mode. When operating in pulse irradiation mode, the emitted laser is a pulsed laser; when operating in continuous irradiation mode, the emitted laser is a continuous laser.

[0010] Optionally, the illumination beam of at least one laser is a Gaussian beam.

[0011] Optionally, the laser head is equipped with a magnetic attraction structure, and the support component is equipped with a magnetic attraction structure corresponding to the laser head.

[0012] Optionally, the bottom of the degassing furnace cavity is provided with a positioning slot; the bottom of the support component is provided with a locking kit corresponding to the positioning slot.

[0013] Optionally, a dual-color laser is also included for measuring the temperature of the surface of the degassed parts.

[0014] The present invention also provides a degassing method using the above-mentioned Dewar heating degassing device, comprising the following steps: Place the degassing components into the degassing furnace cavity; A low temperature is provided to the glass furnace wall through heating wires; The laser is aimed at the heating area to heat it. By adjusting the support components, galvanometer, or mask device, different parts or different areas of the same part are heated and degassed at different temperatures simultaneously. The heating process described above also includes using a dual-color laser to measure the temperature of the heated area on the surface of the degassing part. If the temperature does not reach the rated temperature, heating continues; if the temperature reaches the rated temperature, the laser heating power is reduced to maintain the temperature of the heated area at the rated temperature. After degassing the heating area, the heating position is adjusted by adjusting the support components, galvanometer, or mask device. Continue heating and degassing.

[0015] Optionally, the laser operates in pulse irradiation or continuous irradiation mode. When operating in pulse irradiation mode, the emitted laser is a pulsed laser; when operating in continuous irradiation mode, the emitted laser is a continuous laser.

[0016] Optionally, the illumination beam of at least one laser is a Gaussian beam.

[0017] Optionally, the laser head is equipped with a magnetic attraction structure, and the support component is equipped with a magnetic attraction structure corresponding to the laser head.

[0018] Optionally, the bottom of the degassing furnace cavity is provided with a positioning slot; the bottom of the support component is provided with a locking kit corresponding to the positioning slot.

[0019] The present invention also provides a degassing method using the above-mentioned Dewar heating degassing device, comprising the following steps: Place the degassing components into the degassing furnace cavity; A low temperature is provided to the glass furnace wall through heating wires; The laser is aimed at the heating area to heat it. By adjusting the support components, galvanometer, or mask device, different parts or different areas of the same part are heated and degassed at different temperatures simultaneously. The heating process described above also includes using a dual-color laser to measure the temperature of the heated area on the surface of the degassing part. If the temperature does not reach the rated temperature, heating continues; if the temperature reaches the rated temperature, the laser heating power is reduced to maintain the temperature of the heated area at the rated temperature. After degassing the heating area, the heating position is adjusted by adjusting the support components, galvanometer, or mask device. Continue heating and degassing.

[0020] Compared with existing technologies, the advantages of this invention are as follows: the laser beam path of the degassing device in this application directly irradiates the surface of the workpiece without refraction through the glass furnace wall, avoiding changes in the spatiotemporal characteristics of the laser and enabling accurate irradiation at the set position. After chip bonding, the Dewar can still thoroughly degas the adhesive (the material with the highest gas content) through zoned heating. Degassing the adhesive effectively improves the vacuum life without affecting the chip's performance. This invention can simultaneously and thoroughly degas components with different heat resistance and different heat-resistant materials on the components, greatly improving the degassing efficiency of the degassing furnace. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a Dewar heating and degassing device according to the present invention; Figure 2 Here is a schematic diagram of the structure of the laser head and galvanometer module in this invention; Figure 3 This is a schematic diagram of another Dewar heating and degassing device of the present invention; Figure 4 This is a schematic diagram of another Dewar heating and degassing device of the present invention; Figure 5This is a schematic diagram of another degassing furnace and supporting device according to the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the scope of protection of the present invention. Obviously, the embodiments described in this invention are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1

[0024] Please refer to Figure 1 In a preferred embodiment of the present invention, based on the aforementioned problems existing in the prior art, a Dewar heating degassing device is provided, comprising: a degassing furnace cavity 100; a furnace door 101 and a sealing rubber ring 102; an optical fiber 121 penetrating the side wall of the cavity; a water-cooling pipe 130 wound around the outer periphery of the optical fiber, wherein in this embodiment, the water-cooling pipe 130 is spirally wound; a beam splitter assembly 210; a support component 300 located within the degassing furnace cavity 100 for fixing the degassing components; a galvanometer module 200 located within the degassing furnace cavity for adjusting the irradiation position of the emitted beam; and a laser head 110 located within the degassing furnace cavity for adjusting the shape and size of the emitted beam. The beam splitter assembly 210 is positioned closest to the laser and can split the emitted laser into multiple laser beams of the same or different preset energies, allowing simultaneous heating of heating areas with different or dispersed heating requirements for the same component, or simultaneous heating of different components. In this embodiment, the beam splitter assembly 210 can split the emitted laser into three laser beams of different energies.

[0025] Please refer to Figure 2 When the laser passes through the laser head 110 equipped with a conical lens 111, the laser head 110 shapes the laser to form an annular laser irradiation area as shown in 1111; when the laser passes through the laser head 110 equipped with a cylindrical mirror 112, the laser head 110 shapes the laser to form a linear laser irradiation area as shown in 1121; when the laser passes through the laser head 110 equipped with cylindrical mirrors 112 arranged in a cross pattern, the laser head 110 shapes the laser to form a planar laser irradiation area as shown in 1122.

[0026] Please continue to refer to this. Figure 2The galvanometer module 200 includes multiple galvanometers 201, two in this embodiment. In other embodiments, the number of galvanometers used can be increased or decreased as needed. All galvanometers 201 are mounted on the XYZ movable platform (not shown). The galvanometer module 200 is used to change the laser transmission path, thereby changing the laser irradiation range. Furthermore, the galvanometers 201 themselves can move or rotate, thereby further changing the position of the laser irradiation range according to the processing needs.

[0027] In this embodiment, specifically, the glass degassing furnace cavity is made of glass, and the optical fiber and cavity wall, the XYZ movable platform of the galvanometer module and the base are encapsulated by brazing; specifically, there is a sealing structure at the connection position of the optical fiber and cavity wall, the XYZ movable platform of the galvanometer module and the base, which is sealed after installation and brazing.

[0028] In this embodiment, specifically, a laser (not shown) is also included, which is used to provide a point-like initial light source.

[0029] In this embodiment, specifically, it also includes a support component 300; the support component 300 has a chassis, a fixed clamp, a rotating shaft that drives the chassis to move horizontally or rotate, and a lifting component that drives the chassis to move vertically, used to fix the degassing parts during degassing work and adjust the position of the degassing parts according to the processing needs; when processing a cylindrical degassing part 502, the support component 300 drives it to rotate horizontally and move vertically, and when processing a rectangular degassing part 501, the support component 300 drives it to reciprocate horizontally and move vertically.

[0030] In this embodiment, optionally, the laser operates in pulsed irradiation mode. When the operating mode is continuous irradiation, the emitted laser is a continuous laser. During degassing, prolonged heating of one area can cause temperature increases in surrounding areas. By outputting pulsed lasers, an alternating hot and cold state is achieved in the irradiated area, reducing the efficiency of heat conduction in the degassing components. This allows for effective heating of only the laser-irradiated area without significantly affecting the temperature of the surrounding area. When the surrounding area is also made of a material with good heat resistance, but with lower heat resistance than the irradiated area, continuous laser irradiation can be used to heat the components; the residual heat conducted to the surrounding area then provides residual heating.

[0031] In this embodiment, optionally, when the laser emits a planar laser in a pulsed irradiation mode, the planar laser is preferably a laser with a pulse width of 10-50ms and a frequency of 20-60Hz.

[0032] In this embodiment, optionally, one of the lasers emits a Gaussian beam; the beam expander located in the laser head 110 can adjust the spot size according to the irradiation area to directly irradiate and heat the circular area; alternatively, the conical lens 111 in the laser head 110 can shape the spot into a ring-shaped spot to heat the annular heating area; or the two cross-shaped cylindrical mirrors 112 in the laser head 110 can shape the laser into a planar shape to heat the entire surface; in this case, the laser power needs to be increased to make the entire irradiation area significantly heated.

[0033] In this embodiment, optionally, the laser head 110 is equipped with a magnetic attraction structure (not shown), and the corresponding support component 300 is also equipped with a magnetic attraction structure, so that the laser head 110 can be fixed by proximity and self-adsorption, which facilitates alignment with the irradiation heating area.

[0034] In this embodiment, optionally, a dual-color laser (not shown) is also included, which is used to measure the temperature of the surface of the degassing parts, thereby ensuring real-time monitoring of the heating temperature of the degassing parts in a non-contact manner.

[0035] In this embodiment, optionally, the two wavelengths of the two-color laser emitted by the dual-color laser are 0.8 micrometers and 1.0 micrometers, respectively.

[0036] In this embodiment, optionally, a heating wire is also provided in the degassing furnace cavity 100 to provide a low temperature for the degassing furnace. Therefore, in other embodiments, the heating wire may not be provided.

[0037] In this embodiment, optionally, the support component 300 also includes a clamp (not shown), which can better fix the degassing component.

[0038] Example 2

[0039] Please refer to Figure 3 The present invention also provides a Dewar heating degassing device, including the Dewar heating degassing device of Embodiment 1, and further including a mask device 401. The mask device 401 is located closest to the support component 300. Depending on the processing requirements, the material selected is an opaque, high-temperature resistant metal or glass with a certain light transmittance. In this embodiment, the beam splitter group 210 divides the emitted laser into 6 laser beams with different energies. Three of these beams are shaped into planar lasers by the laser head 110. The mask device 401 is provided on the optical path of each of these three planar laser beams. During the degassing process, the mask device 401 is used to shield areas that do not require superimposed heating or areas with low temperature (80-200℃) heating, thereby achieving the effect of full and partial shielding of laser thermal radiation.

[0040] In this embodiment, the mask device 401 is specifically mounted on the XYZ movable platform (not shown), allowing the mask device 401 to move during processing, thereby enabling the masking of different parts as needed during processing. The XYZ movable platform of the mask device is encapsulated with the base by brazing, similar to the encapsulation method between the galvanometer module and the base in Embodiment 1. Specifically, a sealing structure is provided at the connection position between the XYZ movable platform of the mask device and the base, and sealing is performed after installation and brazing.

[0041] Please refer to Figure 4 An even number of lasers in different directions can be set inside the degassing furnace cavity 100 to achieve more uniform heating of the degassed parts; the mask device 401 can also be set only on one side, or multiple mask devices 401 of different sizes, materials and shapes can be set to simultaneously heat the heating areas of the same part with different temperature requirements, while no mask device is set on the other side, and point laser is used for heating the heating areas of the degassed parts with high temperature requirements; and the heating area can be changed by moving the part by the support component 300 or by the galvanometer module 200.

[0042] This embodiment uses a mask device 401 to shield irregular areas from heating zones that do not require overlapping or areas requiring low-temperature (80-200℃) heating, achieving both full and partial shielding of laser thermal radiation. This allows for zoned heating of the same part. Furthermore, the mask device 401 can be installed on only one side of the fireplace, such as... Figure 4 As shown, the laser emitted by the laser measuring device becomes a parallel laser after passing through the galvanometer module, resulting in a large irradiation area. A mask device is used to shield areas that do not require heating, effectively achieving simultaneous degassing of multiple parts on the degassing component while protecting areas resistant to lower degassing temperatures. On the other side, a high-power point laser is used for direct heating to meet the needs of special processing of certain parts, such as the adhesive portion of a bonded chip. In this embodiment, the mask device can be a device with transparent and opaque areas. Preferably, the transparent areas are set with different transmittances, such as 10%, 20%, 50%, and 80%, so that the heating temperature will be different under different transmittances. This achieves simultaneous degassing of different areas of the same component. In this embodiment, the preferred mask device is a glass plate.

[0043] Example 3

[0044] refer to Figure 5The present invention also provides a degassing furnace cavity 100 and a supporting component 300; the difference from embodiment 1 is that a positioning groove 1001 is provided on the bottom surface of the degassing furnace cavity 100, and a locking kit 310 corresponding to the positioning groove 1001 is provided on the bottom surface of the supporting component 300; the locking kit 310 is composed of a locking spring 311 and a locking slot 312; the positioning groove 1001 is a concave pit with an arc; the locking kit 310 has a locking spring 311 and a locking slot 312 with an arc protrusion corresponding to the groove; when the degassing component is installed, the degassing component is locked by the locking spring 311, and then the component and the supporting component 300 are slid into the cavity, so that the arc protrusion is located in the arc concave pit for fixation.

[0045] In this embodiment, the separation of the degassing furnace cavity 100 and the support component 300 is achieved through the positioning slot 1001 and the locking kit 310, which facilitates the placement, fixing and collection of the degassing parts after processing, and also makes it easy to replace the appropriate support component according to the volume of the degassing parts.

[0046] Example 4

[0047] The present invention also provides a degassing method using a Dewar heating degassing device, comprising the following steps: Place the degassing components into the degassing furnace cavity; A low temperature is provided to the glass furnace wall through heating wires; The laser is aimed at the heating area to heat it. By adjusting the support components, galvanometer, or mask device, different parts or different areas of the same part are heated and degassed at different temperatures simultaneously. During the heating process, a dual-color laser is used to measure the temperature of the heated area on the surface of the degassing part. If the temperature does not reach the rated temperature, heating continues; if the temperature reaches the rated temperature, the laser heating power is reduced so that the temperature of the heated area is maintained at the rated temperature. After degassing the heating area, the heating position is adjusted by adjusting the support components, galvanometer, or mask device. Continue heating and degassing.

[0048] In this embodiment, the method for measuring the temperature of the degassing component surface using a dual-color laser is to determine the temperature by utilizing the ratio of the infrared radiation energy of the two bands in adjacent channels. Since it can overcome the signal attenuation caused by reflection and absorption from the glass wall, the dual-color laser can still perform accurate non-contact temperature measurement of the component surface outside the glass wall. The power-temperature relationships obtained under different laser power irradiation for different materials are summarized into a laser power-material temperature relationship library.

[0049] The degassing device of this application will be further described below in conjunction with its working method.

[0050] First, a minimum temperature of 50-80°C is provided to the glass furnace wall via heating wires. Based on this minimum temperature, lasers then apply additional heating to different parts or areas.

[0051] Specifically, static heating can be used, which involves heating different parts at different temperatures. Each part is heated by an independent laser, using the power required to reach the target temperature from the laser to irradiate and degas each part. To prevent reflected infrared laser light from irradiating other parts and causing abnormal temperatures, heat insulation baffles can be installed between each part to separate them.

[0052] Alternatively, the same part can be heated in sections. Different sections of the same part are often irregular, involving light sources with complex shapes. Circular and annular heating areas can be achieved through beam shaping. Rectangular heating areas can use lasers emitted from the surface of a vertical resonant cavity or be shaped into planar heating using two cross-shaped cylindrical lenses. In more complex and irregular areas, masking is needed to shield areas that do not require overlapping heating or areas requiring low-temperature (80-200℃) heating, achieving full or partial shielding of laser thermal radiation. The shielding material can be an opaque, high-temperature resistant metal or glass with a certain transmittance (the transmittance is customized according to the required temperature of the masked area).

[0053] Secondly, dynamic heating can be employed. Static heating methods, due to heat accumulation and conduction, can lead to higher temperatures in adjacent areas of the directly irradiated region. Therefore, it's necessary to reduce the actual heating range to minimize the impact of heat conduction. Dynamic heating avoids this problem, preventing heat accumulation and conduction from causing excessively high temperatures in adjacent areas. The moving laser or component only reaches its target temperature within its irradiated area; in unirradiated areas, the temperature decreases rapidly, and the thermal impact on adjacent areas is negligible.

[0054] Specifically, heating can be achieved through the motion of parts, which are clamped (magnetically-adhesive parts can also be magnetically attracted) onto a fixture. The laser source remains stationary; cylindrical parts rotate via a pivot, while planar parts reciprocate in a single direction, thus achieving heating through motion. After chip packaging, a heating laser can be used to locally heat the adhesive surface without causing the chip temperature to exceed its heat resistance threshold.

[0055] The heating lasers used are of two types: point laser and surface laser. The point laser continuously irradiates the adhesive between the two planes, causing the irradiated area to rapidly heat up to the maximum degassing temperature, while the Dewar is clamped and rotated by a fixture. The surface laser is a pulsed laser with a pulse width of 10-50ms and a frequency of 20-60Hz. Through continuous flashing, the irradiated area undergoes a rapid heating and cooling process, thereby degassing the adhesive.

[0056] Alternatively, laser motion heating can be used. For planar parts, the laser irradiates the surface of the part through a galvanometer, and the laser's motion is achieved by rotating the galvanometer. For cylindrical parts, the laser moves in a circular motion via a ring-shaped slide rail. In actual production, the choice between component motion heating and laser motion heating depends on the degree of degassing required for the parts and the complexity of the process equipment.

[0057] The degassing device in this application avoids laser refraction through the glass furnace wall, thus preventing changes in the laser's spatiotemporal characteristics and ensuring accurate irradiation at the designated location. Even after chip bonding, the Dewar radiator can still effectively degas the adhesive (the material with the highest gas content) through zoned heating. Degassing the adhesive effectively improves vacuum life without affecting chip performance. This invention allows for batch degassing of components with different heat resistances, significantly improving the degassing rate and efficiency of the degassing furnace. The zoned heating method significantly improves the degassing effect of individual components without being affected by the heat resistance of other components in the same batch. Furthermore, by using lenses to shape the laser's spatiotemporal characteristics and employing masking methods, accurate degassing of small areas like adhesive and large areas with complex shapes is achieved. The zoned heating method again significantly improves the degassing effect of individual components without being affected by the heat resistance of other components in the same batch.

[0058] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made using the content of this specification and figures should be included within the protection scope of the present invention.

Claims

1. A Dewar heating and degassing device, characterized in that, include: Degassing furnace cavity; Optical fiber penetrating the sidewall of the cavity; A water-cooling pipe spirally wound around the outer edge of the optical fiber; A laser is connected to one end of the optical fiber outside the cavity. The beam splitter assembly is located inside the degassing furnace cavity, at the position closest to the optical fiber, and is used to split the emitted laser into multiple laser beams with the same or different preset energies. The laser head is set inside the degassing furnace cavity, between the beam splitter group and the degassing components. It includes one or more conical lenses or cylindrical mirrors for receiving the emitted laser and adjusting the shape of the laser so that the emitted laser is a point, ring, line or surface. The galvanometer is mounted on the XYZ movable platform and is located between the laser head and the degassing components. The mask device is located closest to the degassing parts and is made of opaque metal or glass with a certain degree of light transmittance. A support component located inside the gas furnace cavity for fixing the degassing parts, the support component having a chassis, a rotating shaft for driving the chassis to move horizontally or rotate, and a lifting component for driving the chassis to move vertically. And a dual-color laser, used to measure the temperature of the surface of the degassing parts.

2. The Dewar heating and degassing device according to claim 1, characterized in that, The laser operates in either pulsed irradiation or continuous irradiation mode. When operating in pulsed irradiation mode, the emitted laser is a pulsed laser; when operating in continuous irradiation mode, the emitted laser is a continuous laser.

3. The Dewar heating and degassing device according to claim 2, characterized in that, The irradiation beam of at least one laser is a Gaussian beam.

4. The Dewar heating and degassing device according to claim 3, characterized in that, The laser head is equipped with a magnetic attraction structure, and the support component is equipped with a magnetic attraction structure corresponding to the laser head.

5. The Dewar heating and degassing device according to claim 4, characterized in that, The bottom of the degassing furnace cavity is provided with a positioning slot; the bottom of the support component is provided with a locking kit corresponding to the positioning slot.

6. A degassing method using the Dewar heating degassing device according to claim 1, characterized in that, Including the following steps: Place the degassing components into the degassing furnace cavity; A low temperature is provided to the glass furnace wall by heating wires; The laser is aimed at the heating area to heat it. By adjusting the support components, galvanometer, or mask device, different parts or different areas of the same part are heated and degassed at different temperatures simultaneously. The heating process described above also includes using a dual-color laser to measure the temperature of the heated area on the surface of the degassing part. If the temperature does not reach the rated temperature, heating continues; if the temperature reaches the rated temperature, the laser heating power is reduced to maintain the temperature of the heated area at the rated temperature. After degassing the heating area is completed, the heating position is adjusted by adjusting the support components, galvanometer, or mask device. Continue heating and degassing.

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