High-temperature-resistant small optical system packaging structure and packaging method

Abstract

The invention provides a high-temperature-resistant small optical system packaging structure and packaging method, and relates to the technical field of optical system packaging. According to the packaging method, firstly, high-temperature-resistant ceramic is used for preparing a high-temperature-resistant ceramic packaging structure base, and then small optical systems formed through sequential stacking are bonded to the high-temperature-resistant ceramic packaging structure base; and then, in a water-free and oxygen-free environment, an indium-based sealing welding ring is used, and welding among the high-temperature-resistant ceramic packaging shell, the indium-based sealing welding ring and the high-temperature-resistant ceramic packaging structure base is completed at low temperature. The thermal damage of low-temperature welding to devices in a small optical system is small, the residual thermal stress is small, the air tightness of a physical system is good, and the obtained packaging structure can keep high stability and air tightness in a high-temperature environment. The packaging structure base and the packaging shell of the packaging structure are both made of high-temperature-resistant ceramic, the overall thermal expansion of the packaging structure is consistent, and damage caused by inconsistent stress when the packaging structure works in a high-temperature environment is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of optical system packaging, and in particular to a high-temperature resistant small optical system packaging structure and a packaging method. Background Art

[0002] In optical systems, the stability and airtightness of the packaging structure are key factors. The quality of the packaging effect of components directly determines the performance of the optical system. Component packaging performed at room temperature is prone to aging and decomposition of packaging materials when working in a high-temperature environment. In addition, under high-temperature conditions, the contact surface of solder with different packaging materials is prone to large thermal mismatch due to the different thermal expansion coefficients, thereby causing residual thermal stress and directly reducing packaging reliability.

[0003] At present, electronic components packaged in plastic cannot withstand high temperature environments, while electronic components packaged in metal are large and bulky, making it difficult to meet usage requirements. Although high-temperature / low-temperature co-fired ceramic substrates can be used for hermetic packaging of high-temperature microsystems, due to the low circuit accuracy of these substrates, it is difficult to meet the packaging requirements of miniaturization and integration of high-temperature microsystems. In high-temperature environments, traditional packaging structures may not be able to maintain stability and may have airtightness issues.

[0004] In some applications, such as atomic clock physics systems or other high-precision optical systems, it is necessary to package optical components and related devices in a miniaturized structure and maintain high stability and airtightness in high temperature environments. However, existing packaging technologies have problems such as insufficient stability and poor airtightness in high temperature environments, which cannot meet the needs of long-term use.

[0005] In view of this, it is necessary to design an improved high temperature resistant small optical system packaging structure and packaging method to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide a high-temperature resistant small optical system packaging structure and packaging method. The packaging method selects a high-temperature resistant ceramic packaging shell and a structural base that are light in weight, resistant to high temperatures, resistant to corrosion, and have a low thermal expansion coefficient as packaging materials. The packaging shell and the structural base are made of the same packaging material, so that the overall thermal expansion of the packaging structure is consistent, avoiding damage caused by inconsistent stress when working in a high-temperature environment; an indium-based sealing welding ring is used to weld high-temperature resistant ceramics in a water-free and oxygen-free environment to prepare a packaging structure base and a packaging shell. The indium-based sealing welding ring requires a low welding temperature, has little thermal damage to other devices in the small optical system, has little residual thermal stress, has good airtightness of the physical system, and can achieve long-term operation; the obtained packaging structure can maintain high stability and airtightness in a high-temperature environment.

[0007] To achieve the above-mentioned object of the invention, the present invention provides a high temperature resistant small optical system packaging method, comprising the following steps:

[0008] S1, laser drilling is performed on the ceramic plate to form small-diameter through holes, followed by surface cleaning;

[0009] S2, depositing a Ti / Cu metal layer as a seed layer on the surface of the ceramic plate obtained in step S1 by using a sputtering coating process;

[0010] S3, using photolithography and development processes to form a mask pattern, then using an electroplating process to fill the through holes and thicken the surface copper layer, then leveling the electroplated copper layer by surface grinding, and forming a Ni / Au layer by surface treatment technology;

[0011] S4, removing the dry film and etching the seed layer to obtain a high temperature resistant ceramic packaging structure base;

[0012] S5, bonding the small optical system to the high temperature resistant ceramic packaging structure base with glue;

[0013] S6, placing the high temperature resistant ceramic packaging shell, the high temperature resistant ceramic packaging structure base with a small optical system obtained in step S5, and the indium-based sealing welding ring in a vacuum box;

[0014] S7, in a water-free and oxygen-free environment, open the vacuum-packed indium-based sealing welding ring, place the indium-based sealing welding ring on the Ni / Au layer of the high-temperature resistant ceramic packaging structure base, and then cover the high-temperature resistant ceramic packaging shell on the high-temperature resistant ceramic packaging structure base with the indium-based sealing welding ring; heat to the welding temperature to completely melt the indium-based sealing welding ring, and complete the welding between the high-temperature resistant ceramic packaging shell-indium-based sealing welding ring-high-temperature resistant ceramic packaging structure base.

[0015] As a further improvement of the present invention, in step S7, the following process is included: using a vacuum pump to evacuate the air in the vacuum box, and then filling the vacuum box with protective gas to form a water-free and oxygen-free environment to prevent the indium-based sealing welding ring from oxidizing; opening the vacuum-packed indium-based sealing welding ring in the protective gas atmosphere, and then covering the high-temperature resistant ceramic packaging shell with the indium-based sealing welding ring on the high-temperature resistant ceramic packaging structure base; then, using a vacuum pump to evacuate the protective gas in the vacuum box, and controlling the vacuum degree to be less than 10Pa; and then heating to the welding temperature through a heating table in the vacuum box to completely melt the indium-based sealing welding ring, thereby completing the welding between the high-temperature resistant ceramic packaging shell-the indium-based sealing welding ring-the high-temperature resistant ceramic packaging structure base.

[0016] As a further improvement of the present invention, in step S7, the welding temperature is 180-200° C. In practical applications, the specific welding temperature can be adjusted according to the equipment status.

[0017] As a further improvement of the present invention, the protective gas is high-purity nitrogen or high-purity argon.

[0018] As a further improvement of the present invention, the small optical system includes a laser light source, an optical lens, a light-atom interaction gas chamber, a heating and temperature control component, a support frame, and a photoelectric signal collector, which are stacked and bonded in sequence.

[0019] As a further improvement of the present invention, in step S1, the diameter of the through hole is 100 um.

[0020] As a further improvement of the present invention, in step S1, the surface cleaning treatment includes the following processes: soaking and ultrasonically oscillating with acetone and anhydrous ethanol in sequence to clean the surface of the ceramic plate, and blowing the surface dry with dry nitrogen to remove organic contamination on the surface of the ceramic plate.

[0021] To achieve the above-mentioned purpose of the invention, the present invention also provides a high-temperature resistant small optical system packaging structure prepared by the above-mentioned scheme, including a high-temperature resistant ceramic packaging structure base, a small optical system bonded to the high-temperature resistant ceramic packaging structure base, a high-temperature resistant ceramic packaging shell covering the high-temperature resistant ceramic packaging structure base, and an indium-based sealing welding ring connecting the high-temperature resistant ceramic packaging structure base and the high-temperature resistant ceramic packaging shell; the contact surface between the high-temperature resistant ceramic packaging structure base and the indium-based sealing welding ring is formed with a Ni / Au layer through surface treatment technology.

[0022] The beneficial effects of the present invention are:

[0023] The packaging structure obtained by the present invention can maintain high stability and air tightness in a high temperature environment, low-temperature welding causes little thermal damage to devices in a small optical system, has little residual thermal stress, and has good air tightness of the physical system.

[0024] The method for packaging a high-temperature resistant small optical system of the present invention first uses high-temperature resistant ceramics to prepare a high-temperature resistant ceramic packaging structure base, and then adheres the small optical system stacked in sequence to the high-temperature resistant ceramic packaging structure base; then, in a water-free and oxygen-free environment, an indium-based sealing welding ring is used to complete the welding between the high-temperature resistant ceramic packaging shell-the indium-based sealing welding ring-the high-temperature resistant ceramic packaging structure base at low temperature. Low-temperature welding causes little thermal damage to the devices in the small optical system, has little residual thermal stress, and has good air tightness of the physical system. The obtained packaging structure can maintain high stability and air tightness in a high-temperature environment. The packaging structure base and the packaging shell of the packaging structure are both made of high-temperature resistant ceramics, and the overall thermal expansion of the packaging structure is consistent, thereby avoiding damage caused by inconsistent stress when working in a high-temperature environment.

[0025] 1. The present invention uses high temperature resistant ceramics to prepare the packaging structure base and the packaging shell. Based on the high temperature tolerance and corrosion resistance of high temperature resistant ceramics, the use of high temperature resistant ceramics to prepare the packaging structure base and the packaging shell can achieve high air tightness and high reliability of the physical system in a high temperature environment, and can meet the needs of long-term use.

[0026] 2. In the present invention, the base and the packaging shell of the packaging structure are both made of high-temperature resistant ceramics, and the overall thermal expansion of the packaging structure is consistent, thereby avoiding damage caused by inconsistent stress when working in a high-temperature environment.

[0027] 3. The packaging method provided by the present invention utilizes an indium-based sealing welding ring to weld high-temperature resistant ceramics to prepare a packaging structure base and a packaging shell during the physical system packaging process. The indium-based sealing welding ring requires a low welding temperature, causes little thermal damage to other devices in the small optical system, has little residual thermal stress, has good airtightness of the physical system, and can achieve long-term operation.

[0028] 4. The present invention utilizes MEMS processes such as sputtering coating and photolithography development to manufacture electrical connection pins in the base of the high-temperature resistant ceramic packaging structure, with high circuit accuracy, which can meet the needs of miniaturization and integration of high-temperature microsystems.

[0029] 5. The small optical system in the present invention is flexible and can be adjusted accordingly according to the specific requirements of the optical system, and can be applied to the fields of atomic clocks, magnetometers, etc. Correspondingly, the size and shape of the high-temperature resistant ceramic packaging shell are flexible and have different heights, which can be adjusted according to the size of the small optical system, which can reduce the volume of the physical system, reduce the weight of the physical system, and make each device have a higher structural density. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a three-dimensional diagram of the high temperature resistant small optical system packaging structure of the present invention.

[0031] Figure 2 It is a schematic diagram of the internal structure of the high temperature resistant small optical system packaging structure of the present invention.

[0032] Figure 3 Schematic diagram of the preparation process of the high temperature resistant ceramic packaging structure base.

[0033] Figure 4 It is a schematic structural diagram of the high temperature resistant small optical system packaging device used in the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the scheme of the present invention are shown in the drawings, while other details that are not closely related to the present invention are omitted.

[0036] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0037] Existing packaging technologies have problems with insufficient stability and poor airtightness in high-temperature environments and cannot meet the needs of long-term use.

[0038] See also Figures 2 to 4 As shown, in order to solve the problem of packaging and miniaturization of optical systems under high temperature conditions, the present invention provides a high temperature resistant small optical system packaging method, comprising the following steps:

[0039] S1, laser drilling is performed on the ceramic plate to form a small aperture through hole of 100um, and then the surface is cleaned;

[0040] The surface cleaning process includes the following steps: sequentially using acetone and anhydrous ethanol to soak and ultrasonically vibrate to clean the surface of the ceramic plate, and blowing the surface dry with dry nitrogen to remove organic contamination on the surface of the ceramic plate.

[0041] S2, depositing a Ti / Cu metal layer as a seed layer on the surface of the ceramic plate obtained in step S1 by using a sputtering coating process;

[0042] S3, using photolithography and development processes to form a mask pattern, then using an electroplating process to fill the through holes and thicken the surface copper layer, then leveling the electroplated copper layer by surface grinding, and forming a Ni / Au layer by surface treatment technology;

[0043] S4, removing the dry film and etching the seed layer to obtain a high temperature resistant ceramic packaging structure base 1; the dry film is the photoresist applied in the previous stage;

[0044] S5, bonding the small optical system to the high temperature resistant ceramic packaging structure base 1 with glue;

[0045] Among them, the small optical system is a small optical system 4, which includes a laser light source 41, a support frame 42, an optical lens, a light-atom interaction chamber 45, a heating and temperature control component 46, and a photoelectric signal collector 47, which are stacked and bonded in sequence by glue. The optical lens includes an attenuation plate 43 and a 1 / 4 wave plate 44. The glue can be EPO-TEK 353ND.

[0046] S6, placing the high temperature resistant ceramic packaging shell 3, the high temperature resistant ceramic packaging structure base with a small optical system obtained in step S5, and the indium-based sealing welding ring 2 in a vacuum box 51;

[0047] See also Figure 4 As shown, the vacuum box 51 is used to provide a water-free and oxygen-free environment, and the vacuum box 51 is provided with a heating platform 55, a shell clamping seat 52 arranged above the heating platform 55, a three-dimensional moving platform 53 connected to the shell clamping seat 52, a vacuum pump 54, an air inlet 57, a gas cylinder 56 connected to the air inlet 57, and an injection port 58. The gas cylinder 56 is filled with a protective gas, such as an inert gas such as high-purity nitrogen or high-purity argon.

[0048] S7, in a water-free and oxygen-free environment, open the vacuum-packed indium-based sealing welding ring, place the indium-based sealing welding ring on the Ni / Au layer of the high-temperature resistant ceramic packaging structure base, and then cover the high-temperature resistant ceramic packaging shell on the high-temperature resistant ceramic packaging structure base with the indium-based sealing welding ring; heat to the welding temperature to completely melt the indium-based sealing welding ring, and complete the welding between the high-temperature resistant ceramic packaging shell-indium-based sealing welding ring-high-temperature resistant ceramic packaging structure base.

[0049] Specifically, step S7 includes the following processes: using a vacuum pump 54 to extract the air in the vacuum box 51, and then filling the vacuum box 51 with a protective gas to form a water-free and oxygen-free environment to prevent the indium-based sealing welding ring 2 from oxidizing; opening the vacuum-packed indium-based sealing welding ring 2 in the protective gas atmosphere, and then covering the high-temperature resistant ceramic packaging shell 3 on the high-temperature resistant ceramic packaging structure base 1 with the indium-based sealing welding ring 2; then, using the vacuum pump 54 to extract the protective gas in the vacuum box 51, and controlling the vacuum degree to be less than 10Pa; and then heating to the welding temperature through the heating table 55 in the vacuum box 51 to completely melt the indium-based sealing welding ring, thereby completing the welding between the high-temperature resistant ceramic packaging shell-the indium-based sealing welding ring-the high-temperature resistant ceramic packaging structure base.

[0050] The welding temperature is 180-200°C. The indium-based sealing welding ring requires a low welding temperature, has little thermal damage to other components in the small optical system, has little residual thermal stress, has good airtightness of the physical system, and can achieve long-term operation.

[0051] See also Figure 1 to Figure 2As shown, the present invention provides a high temperature resistant small optical system packaging structure, including a high temperature resistant ceramic packaging structure base 1, a small optical system 4 bonded to the high temperature resistant ceramic packaging structure base 1, a high temperature resistant ceramic packaging shell 3 covered on the high temperature resistant ceramic packaging structure base 1, and an indium-based sealing welding ring 2 connecting the high temperature resistant ceramic packaging structure base 1 and the high temperature resistant ceramic packaging shell 3. The contact surface between the high temperature resistant ceramic packaging structure base 1 and the indium-based sealing welding ring 2 is formed with a Ni / Au layer through surface treatment technology.

[0052] The present invention uses high temperature resistant ceramics as packaging materials. High temperature resistant ceramics have high temperature tolerance and corrosion resistance. Using high temperature resistant ceramics to prepare the packaging structure base and the packaging shell can achieve high air tightness and high reliability of the physical system in a high temperature environment, and can meet the needs of long-term use. In addition, the high temperature resistant ceramic packaging structure base 1 and the high temperature resistant ceramic packaging shell 3 are made of the same material, and the overall thermal expansion is consistent, avoiding damage caused by inconsistent stress when working in a high temperature environment.

[0053] The present invention selects an indium-based sealing welding ring 2 and welds high-temperature resistant ceramics in a water-free and oxygen-free environment to prepare a packaging structure base 1 and a high-temperature resistant ceramic packaging shell 3. The obtained packaging structure can maintain high stability and airtightness in a high-temperature environment.

[0054] The high temperature resistant small optical system packaging method provided by the present invention is described below in conjunction with specific embodiments.

[0055] Example 1

[0056] A high temperature resistant small optical system packaging method mainly comprises the following steps:

[0057] S1, laser drilling is performed on the ceramic plate to form a through hole with a hole diameter of 100um; then the surface of the ceramic plate is cleaned: acetone and anhydrous ethanol are used to soak and ultrasonically vibrate in sequence to clean the surface of the ceramic plate, and the surface is blown dry with dry nitrogen to remove organic contamination on the surface of the ceramic plate;

[0058] S2, depositing a Ti / Cu metal layer as a seed layer on the surface of the ceramic plate obtained in step S1 by using a sputtering coating process;

[0059] S3, using photolithography and development processes to form a mask pattern, and then using an electroplating process to fill the through hole and thicken the surface copper layer; then, the electroplated copper layer is leveled by surface grinding, and a Ni / Au layer is formed by surface treatment technology;

[0060] S4, removing the dry film and etching the seed layer to complete the preparation of the high temperature resistant ceramic packaging structure base 1;

[0061] S5, according to the installation order of laser light source 41, support frame 42, optical lens (attenuation plate 43, 1 / 4 wave plate 44), light-atom interaction gas chamber 45, heating temperature control component 46, and photoelectric signal collector 47, use adhesive glue to bond to obtain a small optical system 4, and bond the small optical system 4 to the high temperature resistant ceramic packaging structure base 1 with glue;

[0062] S6, placing the high temperature resistant ceramic packaging shell 3, the high temperature resistant ceramic packaging structure base (including the small optical system), and the indium-based sealing welding ring 2 in the vacuum box 51 through the injection port 58;

[0063] S7, install the high temperature ceramic packaging structure base (including the small optical system) in the groove part of the heating platform 55, and install the high temperature ceramic packaging shell 3 on the shell clamping seat 52; the vacuum pump 54 extracts the air in the vacuum box 51, and fills the protective gas high purity nitrogen in the gas cylinder 56 into the vacuum box 51 to form a water-free and oxygen-free environment to prevent the indium-based sealing welding ring from oxidizing; open the vacuum-packed indium-based sealing welding ring in the protective gas atmosphere, and place it on the Ni / Au layer of the high temperature ceramic packaging structure base. Move the high temperature ceramic packaging shell 3 to the high temperature ceramic packaging structure base 1 with the indium-based sealing welding ring 2 through the three-dimensional moving platform 53;

[0064] The vacuum pump 54 extracts the protective gas in the vacuum box 51, and the vacuum degree is less than 10 Pa. The heating table 55 is heated to the welding temperature of 180-200° C. After the indium-based sealing welding ring is completely melted, the welding between the high-temperature resistant ceramic packaging shell-the indium-based sealing welding ring-the high-temperature resistant ceramic packaging structure base is completed.

[0065] Comparative Example 1

[0066] The difference between Comparative Example 1 and Example 1 is that in step S7, no vacuum box is used, that is, no indium-based sealing solder ring is used in a water-free and oxygen-free environment. The rest is substantially the same as Example 1 and will not be described again.

[0067] Experiments show that if a vacuum box environment is not used for indium-based sealing welding rings, the welding rings are prone to oxidation in the atmospheric environment, resulting in poor sealing effects for the entire package, and even causing failure of the entire device.

[0068] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A high temperature resistant small optical system packaging method, characterized in that: The steps include: S1, laser drilling is performed on the ceramic plate to form through holes, and then the surface is cleaned; S2, depositing a Ti / Cu metal layer as a seed layer on the surface of the ceramic plate obtained in step S1 by using a sputtering coating process; S3, using photolithography and development processes to form a mask pattern, then using an electroplating process to fill the through holes and thicken the surface copper layer, then leveling the electroplated copper layer by surface grinding, and forming a Ni / Au layer by surface treatment technology; S4, removing the dry film and etching the seed layer to obtain a high temperature resistant ceramic packaging structure base; S5, bonding the small optical system to the high temperature resistant ceramic packaging structure base with glue; S6, placing the high temperature resistant ceramic packaging shell, the high temperature resistant ceramic packaging structure base with a small optical system obtained in step S5, and the indium-based sealing welding ring in a vacuum box; S7, in a water-free and oxygen-free environment, open the vacuum-packed indium-based sealing welding ring, place the indium-based sealing welding ring on the Ni / Au layer of the high-temperature resistant ceramic packaging structure base, and then cover the high-temperature resistant ceramic packaging shell on the high-temperature resistant ceramic packaging structure base with the indium-based sealing welding ring; heat to the welding temperature to completely melt the indium-based sealing welding ring, and complete the welding between the high-temperature resistant ceramic packaging shell-indium-based sealing welding ring-high-temperature resistant ceramic packaging structure base.

2. The high temperature resistant small optical system packaging method according to claim 1, characterized in that: In step S7, The method comprises the following steps: using a vacuum pump to extract the air in the vacuum box, and then filling the vacuum box with a protective gas to form a water-free and oxygen-free environment to prevent the indium-based sealing welding ring from being oxidized; opening the vacuum-packed indium-based sealing welding ring in the protective gas atmosphere, and then covering the high-temperature resistant ceramic packaging shell with the indium-based sealing welding ring on the high-temperature resistant ceramic packaging structure base; subsequently, using a vacuum pump to extract the protective gas in the vacuum box, and controlling the vacuum degree to be less than 10Pa; and then heating the indium-based sealing welding ring to a welding temperature through a heating table in the vacuum box to completely melt the indium-based sealing welding ring, thereby completing the welding between the high-temperature resistant ceramic packaging shell, the indium-based sealing welding ring, and the high-temperature resistant ceramic packaging structure base.

3. The high temperature resistant small optical system packaging method according to claim 1, characterized in that: In step S7, the welding temperature is 180-200°C.

4. The high temperature resistant small optical system packaging method according to claim 2, characterized in that: The protective gas is high-purity nitrogen or high-purity argon.

5. The high temperature resistant small optical system packaging method according to claim 1, characterized in that: The small optical system comprises a laser light source, an optical lens, a light-atom interaction gas chamber, a heating and temperature control component, a support frame and a photoelectric signal collector which are stacked and bonded in sequence.

6. The high temperature resistant small optical system packaging method according to claim 1, characterized in that: In step S1, the diameter of the through hole is 100 um.

7. The high temperature resistant small optical system packaging method according to claim 1, characterized in that: In step S1, the surface is cleaned. The method comprises the following steps: sequentially using acetone and anhydrous ethanol to soak and ultrasonically vibrate to clean the surface of the ceramic plate, and blowing the surface dry with dry nitrogen to remove organic contamination on the surface of the ceramic plate.

8. A high temperature resistant small optical system packaging structure, characterized in that: Obtained by the packaging method described in any one of claims 1 to 7, comprising a high-temperature resistant ceramic packaging structure base, a small optical system bonded to the high-temperature resistant ceramic packaging structure base, a high-temperature resistant ceramic packaging shell covering the high-temperature resistant ceramic packaging structure base, and an indium-based sealing welding ring connecting the high-temperature resistant ceramic packaging structure base and the high-temperature resistant ceramic packaging shell; a Ni / Au layer is formed on the contact surface between the high-temperature resistant ceramic packaging structure base and the indium-based sealing welding ring by surface treatment technology.

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