Vacuum packaged chip atomic clock getter activation device and use method thereof

Abstract

The invention relates to a vacuum packaged chip atomic clock getter activation device and a use method thereof.The getter activation device is arranged to be of a structure with a heating module on the upper portion and a heat dissipation module on the lower portion, and the heating module and the heat dissipation module are not in contact during use; an inner cavity of an upper groove in the heating module is fully attached to a ceramic sealing cap of the chip atomic clock, the upper groove is heated to the optimal activation temperature of the getter through a PTC heating piece, and then heat preservation is conducted for a period of time, so that it is guaranteed that the getter on the inner wall of the ceramic sealing cap is fully activated; in the activation process, the semiconductor cooler and the water cooling plate in the heat dissipation module are started at the same time, the double heat dissipation structure effectively ensures that the In0. 97Ag0. 03 welding ring located in the lower groove is not melted due to overheating, and therefore the long-term stability of the vacuum degree of the chip atomic clock vacuum packaging cavity is guaranteed. The getter activating device has the advantages of being high in heating speed, good in heat dissipation effect, simple in design, convenient to operate, capable of saving cost and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of chip atomic clock processing, and particularly relates to an getter activation device for a vacuum-packaged chip atomic clock and a using method thereof. Background Art

[0002] Due to its characteristics of low power consumption and good frequency stability, a chip atomic clock can deduce accurate time information within a relatively long time, making up for the deficiency of long-term instability existing in traditional crystal oscillators. The chip atomic clock is widely used because it can improve the positioning, navigation, and timing accuracy, and is a key part of autonomous positioning, navigation, and timing.

[0003] A chip atomic clock needs to operate in a high-vacuum environment, so eutectic solder ring vacuum packaging is required for the chip atomic clock. In order to protect the devices inside the chip atomic clock from being damaged by high temperature during the eutectic soldering process, the solder ring material for eutectic soldering usually uses In 0.97 Ag 0.03 . The melting point of In 0.97 Ag 0.03 material is 143°C, and the temperature of eutectic soldering is usually selected at 185°C.

[0004] The maintenance of the vacuum degree after its vacuum packaging affects the performance of the device. Therefore, in order to maintain the long-term stability of the vacuum degree of the chip atomic clock vacuum packaging chamber, a thin film getter needs to be sputtered inside the chamber. Generally, the getter applicable to the chip atomic clock vacuum packaging is a non-evaporable getter (NEG), which does not need to go through an evaporation process and change its shape during the activation process. Currently, the activation temperature of the getter is basically above 200°C, and the optimal activation temperature is generally around 300°C. If the directly heating activation method is used for the chip atomic clock after vacuum packaging, it will cause the In0.97Ag0.03 solder ring material to melt, thus damaging the entire vacuum packaging.

[0005] Therefore, in order to ensure the activation of the chip atomic clock getter after vacuum packaging on the premise that the In 0.97 Ag 0.03 solder ring material is not damaged, it is urgent to design a getter activation device for a vacuum-packaged chip atomic clock and a using method thereof to solve the problems existing in the above-mentioned prior art. Summary of the Invention

[0006] In view of this, the present invention provides a getter activation device for a vacuum-packaged chip atomic clock and a using method thereof, aiming to activate the chip atomic clock getter on the premise that the In 0.97 Ag 0.03 solder ring material is not damaged, and ensure the vacuum degree of the chip atomic clock during use.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A getter activation device for a vacuum-packaged chip atomic clock, characterized in that the getter activation device comprises a controller, a heating module and a heat dissipation module;

[0009] The controller controls the heating module and the heat dissipation module respectively;

[0010] The heating module includes an upper groove, a Pt100 temperature-sensing resistor and a PTC heating sheet. The Pt100 temperature-sensing resistor is fixedly installed on the top of the upper groove, and the PTC heating sheet is attached to the top of the upper groove during use;

[0011] The heat dissipation module includes a lower groove, a semiconductor refrigerator and a water-cooled plate. During use, first attach the heat dissipation surface of the semiconductor refrigerator to the water-cooled plate, and then attach the bottom of the lower groove to the refrigeration surface of the semiconductor refrigerator;

[0012] During use, first place the chip atomic clock in the lower groove, and then cover the upper groove on the chip atomic clock, and ensure that the upper groove and the lower groove do not contact.

[0013] Further, the inner cavity depth of the lower groove is designed according to the position of the In 0.97 Ag 0.03 solder ring of the chip atomic clock. Its depth needs to ensure that when the chip atomic clock is placed in the lower groove, the In 0.97 Ag 0.03 solder ring is located within the lower groove.

[0014] Further, the upper groove is made of copper material, and the shape of the inner cavity of the upper groove matches the shape of the upper part of the chip atomic clock.

[0015] Further, the lower groove is made of copper material, and the shape of the inner cavity of the lower groove matches the shape of the lower part of the chip atomic clock.

[0016] Further, the Pt100 temperature-sensing resistor is used to monitor the temperature of the upper groove in real time and transmit the temperature information to the controller. The controller controls whether the PTC heating sheet works according to the temperature information; the controller controls the semiconductor refrigerator and the water-cooled plate to generate a refrigeration effect, which is used to dissipate heat from the lower part of the chip atomic clock during the getter activation process.

[0017] Further, the PTC heating sheet is attached to the top of the upper groove through silicone grease during use; the heat dissipation surface of the semiconductor refrigerator is attached to the water-cooled plate through silicone grease, and the bottom of the lower groove is attached to the refrigeration surface of the semiconductor refrigerator through silicone grease.

[0018] Further, the water-cooling plate is provided with a water inlet and a water outlet. When the water-cooling plate starts to work, the cooling water enters the water-cooling plate through the water inlet and flows out through the water outlet for circulating heat dissipation.

[0019] The present invention also provides a method for using the getter activation device of the chip atomic clock based on the above-mentioned vacuum encapsulation. The method includes the following steps:

[0020] S1. Place the packaged chip atomic clock into the lower groove of the getter activation device, and then cover the upper groove on the chip atomic clock, ensuring that the upper groove and the lower groove do not contact.

[0021] S2. The controller controls the PTC heating sheet to electrically heat, so that the upper groove quickly heats up. The Pt100 temperature-sensing resistor real-time monitors the temperature of the upper groove and transmits the temperature information to the controller. When the Pt100 temperature-sensing resistor monitors that the temperature reaches the optimal activation temperature of the getter, the controller controls the PTC heating sheet to keep the temperature of the upper groove maintained at the optimal activation temperature for a period of time to ensure that the getter on the inner wall of the ceramic cap is fully activated.

[0022] S3. At the same time, the controller controls the semiconductor refrigerator to generate a refrigeration effect and controls the water-cooling plate to start working. The refrigerating surface of the semiconductor refrigerator absorbs the heat at the lower part of the chip atomic clock and transfers the heat to the water-cooling plate through the heat dissipation surface of the semiconductor refrigerator to ensure that the In 0.97 Ag 0.03 solder ring does not melt due to overheating.

[0023] S4. After the heat preservation is completed, the controller first controls the PTC heating sheet to stop working. When the Pt100 temperature-sensing resistor monitors that the temperature of the upper groove is lower than the melting point of the solder ring material, the controller controls the semiconductor refrigerator and the water-cooling plate to stop working.

[0024] S5. Remove the upper groove from the chip atomic clock and take out the chip atomic clock with the getter activated.

[0025] Further, the heat preservation time of the upper groove in step S2 is thirty minutes.

[0026] Further, the optimal activation temperature of the getter in step S2 is 300 °C, and the melting point of the solder ring material in step S4, that is, the melting point of the In 0.97 Ag 0.03 material is 143 °C. Compared with the prior art, the beneficial effects of the present invention are:

[0027] (1) By setting the getter activation device with a structure where the upper part is a heating module and the lower part is a cooling module, and the heating module and the cooling module do not contact during use. The inner cavity of the upper groove in the heating module fully fits the ceramic cap of the chip atomic clock. Use the PTC heating sheet to heat the upper groove to the optimal activation temperature of the getter and keep it warm for a period of time to ensure that the getter on the inner wall of the ceramic cap is fully activated. During the activation process, simultaneously start the semiconductor refrigerator and the water-cooled plate in the cooling module. The dual cooling structure effectively ensures that the In 0.97 Ag 0.03 solder ring will not melt due to overheating, thus ensuring the long-term stability of the vacuum degree of the vacuum encapsulation chamber of the chip atomic clock. The getter activation device in the present invention has the characteristics of fast heating speed, good cooling effect, simple design, convenient operation, cost saving, etc. And it can be applied to the getter activation process of other vacuum encapsulation structures of the same type.

[0028] (2) The upper groove is made of copper material with good thermal conductivity, and the inner cavity of the upper groove is designed according to the shape of the upper part of the chip atomic clock, ensuring that the inner cavity of the upper groove fully fits the lower part of the chip atomic clock, which helps to quickly conduct the heat generated by the PTC heating sheet to the chip atomic clock, so as to more effectively activate the getter sputtered in the ceramic cap of the chip atomic clock.

[0029] (3) The inner cavity depth of the lower groove is designed according to the position of the In 0.97 Ag 0.03 solder ring of the chip atomic clock. Its depth needs to ensure that when the chip atomic clock is placed in the lower groove, the In 0.97 Ag 0.03 solder ring of the chip atomic clock is located within the lower groove. At the same time, the lower groove is made of copper material with good thermal conductivity, and the inner cavity of the lower groove is designed according to the shape of the lower part of the chip atomic clock, ensuring that the inner cavity of the lower groove fully fits the lower part of the chip atomic clock, which helps to quickly conduct the heat of the chip atomic clock to the semiconductor refrigerator, thus effectively protecting the In 0.97 Ag 0.03 solder ring from melting due to overheating.

[0030] Other features and advantages of the present invention will be described in the subsequent specification, and, in part, will become apparent from the specification or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures pointed out in the specification and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0032] Figure 1 Fig. 4 shows a three-dimensional structural schematic diagram of the getter activation device of the chip atomic clock with vacuum packaging according to the embodiment of the present invention;

[0033] Figure 2 Fig. 8 shows a three-dimensional structural schematic diagram of the appearance of the chip atomic clock after vacuum packaging according to the embodiment of the present invention. In the figure: 1, Pt100 temperature-sensing resistor; 2, PTC heating sheet; 3, upper groove; 4, chip atomic clock; 4-1, ceramic sealing cap; 4-2, ceramic tube shell; 4-3, In 0.97 Ag 0.03 solder ring; 5, lower groove; 6, semiconductor refrigerator; 7, water-cooling plate; 7-1, water inlet; 7-2, water outlet. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0035] An embodiment of the present invention provides a getter activation device for a chip atomic clock with vacuum packaging. As shown in the attached Figure 1-2 figures, the getter activation device includes a controller, a heating module and a heat dissipation module;

[0036] The controller controls the heating module and the heat dissipation module respectively;

[0037] The heating module includes an upper groove 3, a Pt100 temperature-sensing resistor 1 and a PTC heating sheet 2. The Pt100 temperature-sensing resistor 1 is fixedly installed on the top of the upper groove 3, and the PTC heating sheet 2 is attached to the top of the upper groove 3 during use;

[0038] The heat dissipation module includes a lower groove 5, a semiconductor refrigerator 6 and a water-cooling plate 7. During use, first attach the heat dissipation surface of the semiconductor refrigerator 6 to the water-cooling plate 7, and then attach the bottom of the lower groove 5 to the refrigeration surface of the semiconductor refrigerator 6;

[0039] During use, first place the chip atomic clock 4 into the lower groove 5, and then cover the upper groove 3 on the chip atomic clock 4, ensuring that the upper groove 3 and the lower groove 5 do not come into contact.

[0040] The inner cavity depth of the lower groove 5 is designed according to the position of the In 0.97 Ag 0.03 solder ring 4-3 of the chip atomic clock 4. Its depth should be ensured so that when the chip atomic clock 4 is placed in the lower groove 5, the In 0.97 Ag 0.03 solder ring 4-3 of the chip atomic clock 4 is located within the lower groove 5.

[0041] The upper groove 3 is made of copper material, and the shape of the inner cavity of the upper groove 3 matches the shape of the upper part of the chip atomic clock 4. The upper groove is made of copper material with good thermal conductivity, and the inner cavity of the upper groove is designed according to the shape of the upper part of the chip atomic clock, ensuring that the inner cavity of the upper groove fits closely with the upper part of the chip atomic clock, which helps to quickly conduct the heat generated by the PTC heating sheet to the chip atomic clock, so as to more effectively activate the getter sputtered in the ceramic cap of the chip atomic clock.

[0042] The lower groove 5 is made of copper material, and the shape of the inner cavity of the lower groove 5 matches the shape of the lower part of the chip atomic clock 4. The lower groove is made of copper material with good thermal conductivity, and the inner cavity of the lower groove is designed according to the shape of the lower part of the chip atomic clock, ensuring that the inner cavity of the lower groove fits closely with the lower part of the chip atomic clock, which helps to quickly conduct the heat of the chip atomic clock to the semiconductor refrigerator, thereby effectively protecting the In 0.97 Ag 0.03 solder ring from melting due to overheating.

[0043] The Pt100 temperature sensing resistor 1 is used to monitor the temperature of the upper groove 3 in real time and transmit the temperature information to the controller. The controller controls whether the PTC heating sheet 2 works according to the temperature information; the controller controls the semiconductor refrigerator 6 and the water cooling plate 7 to produce a refrigeration effect, which is used to dissipate heat from the lower part of the chip atomic clock during the activation process of the getter.

[0044] The PTC heating sheet 2 is attached to the top of the upper groove 3 with silicone grease during use; the heat dissipation surface of the semiconductor refrigerator 6 is attached to the water cooling plate 7 with silicone grease, and the bottom of the lower groove 5 is attached to the refrigeration surface of the semiconductor refrigerator 6 with silicone grease. When connecting the above parts, silicone grease is applied to the contact surface, which can make the heat conduction effect better.

[0045] The water cooling plate 7 is provided with a water inlet 7-1 and a water outlet 7-2. When the water cooling plate 7 starts to work, the cooling water enters the water cooling plate 7 through the water inlet 7-1 and flows out through the water outlet 7-2 for circulating heat dissipation.

[0046] The present invention also provides a method for using the vacuum-encapsulated chip atomic clock getter activation device, which is as follows:

[0047] The packaging module of the chip atomic clock 4 of the present invention mainly consists of a ceramic sealing cap 4-1, a ceramic tube shell 4-2 and an In 0.97 Ag 0.03 Before packaging, the inner wall of the ceramic cap 4-1 is pre-sputtered with a getter, the activation temperature of which is above 200°C, and the optimal activation temperature is 300°C. 0.97 Ag 0.03 The material is welded to the ceramic tube shell 4-2 and the ceramic cap 4-1 by vacuum eutectic welding process, and the packaging vacuum degree is 10 -5 Pa, In 0.97 Ag 0.03 The optimal packaging temperature of the material is 185°C, but at this packaging temperature, the getter activation conditions cannot be met. In order to activate the getter, after packaging is completed, the chip atomic clock is activated by a getter activation device. The method of use includes the following steps:

[0048] S1. Place the packaged chip atomic clock 4 into the lower groove 5 of the getter activation device, then cover the upper groove 3 on the chip atomic clock 4, and ensure that the upper groove 3 and the lower groove 5 do not touch;

[0049] S2. The controller controls the PTC heater 2 to electrically heat the upper groove 3, rapidly heating it. The Pt100 temperature-sensing resistor 1 monitors the temperature of the upper groove 3 in real time and transmits the temperature information to the controller. When the Pt100 temperature-sensing resistor 1 detects that the temperature has reached the optimal activation temperature of the getter, the controller controls the PTC heater 2 to maintain the temperature of the upper groove 3 at the optimal activation temperature for a period of time to ensure that the getter on the inner wall of the ceramic cap 4-1 is fully activated.

[0050] S3. At the same time, the controller controls the semiconductor cooler 6 to produce a cooling effect, and at the same time controls the water-cooled plate 7 to start working. The cooling surface of the semiconductor cooler 6 absorbs the heat from the lower part of the chip atomic clock 4 and transfers the heat to the water-cooled plate 7 through the heat dissipation surface of the semiconductor cooler 6 to ensure that the In in the lower groove 5 is 0.97 Ag 0.03 The welding ring 4-3 does not melt due to overheating;

[0051] S4. After the insulation is completed, the controller first controls the PTC heater 2 to stop working. When the Pt100 temperature-sensing resistor 1 detects that the temperature of the upper groove 3 is lower than the melting point of the welding ring material, the controller controls the semiconductor cooler 6 and the water-cooled plate 7 to stop working.

[0052] S5. Remove the upper groove 3 from the chip atomic clock 4, and take out the chip atomic clock 4 for which the getter activation is completed.

[0053] In step S2, the heat preservation time of the upper groove 3 is thirty minutes.

[0054] In step S2, the optimal activation temperature of the getter is 300 °C. The melting point of the solder ring material in step S4, that is, the melting point of the In 0.97 Ag 0.03 material is 143 °C.

[0055] In the present invention, the getter activation device is configured such that the upper part is a heating module and the lower part is a heat dissipation module, and the heating module and the heat dissipation module do not contact during use. The inner cavity of the upper groove in the heating module fully fits the ceramic cap of the chip atomic clock. After heating the upper groove to the optimal activation temperature of the getter by using a PTC heating sheet and keeping it warm for a period of time, it is ensured that the getter on the inner wall of the ceramic cap is fully activated; during the activation process, the semiconductor refrigerator and the water-cooled plate in the heat dissipation module are started simultaneously, and the dual heat dissipation structure effectively ensures that the In 0.97 Ag 0.03 solder ring in the lower groove does not melt due to overheating, thereby ensuring the long-term stability of the vacuum degree of the vacuum encapsulation chamber of the chip atomic clock. The getter activation device in the present invention has the characteristics of fast heating speed, good heat dissipation effect, simple design, convenient operation, cost saving, etc. And it can be applied to the getter activation process of other vacuum encapsulation structures of the same type.

[0056] Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A getter activation device for a vacuum-packaged chip atomic clock, characterized in that The getter activation device includes a controller, a heating module, and a heat dissipation module; The controller controls the heating module and the heat dissipation module respectively; The heating module includes an upper groove (3), a Pt100 temperature sensor resistor (1), and a PTC heating sheet (2). The Pt100 temperature sensor resistor (1) is fixedly installed on the top of the upper groove (3), and the PTC heating sheet (2) is attached to the top of the upper groove (3) during use; The heat dissipation module includes a lower groove (5), a semiconductor refrigerator (6), and a water cooling plate (7). During use, first attach the heat dissipation surface of the semiconductor refrigerator (6) to the water cooling plate (7), and then attach the bottom of the lower groove (5) to the refrigeration surface of the semiconductor refrigerator (6); During use, first place the chip atomic clock (4) into the lower groove (5), and then cover the upper groove (3) on the chip atomic clock (4), ensuring that the upper groove (3) and the lower groove (5) do not touch.

2. The getter activation device for the vacuum-packaged chip atomic clock according to claim 1, wherein The inner cavity depth of the lower groove (5) is designed according to the position of the In 0.97 Ag 0.03 solder ring (4-3) of the chip atomic clock (4). Its depth needs to ensure that when the chip atomic clock (4) is placed in the lower groove (5), the In 0.97 Ag 0.03 solder ring (4-3) is located within the lower groove (5).

3. The getter activation device for a vacuum-packaged chip atomic clock according to claim 2, wherein The upper groove (3) is made of copper material, and the inner cavity shape of the upper groove (3) matches the upper part shape of the chip atomic clock (4).

4. The getter activation device for a vacuum-packaged chip atomic clock according to claim 3, wherein, The lower groove (5) is made of copper material, and the inner cavity shape of the lower groove (5) matches the lower part shape of the chip atomic clock (4).

5. The getter activation device for a vacuum-packaged chip atomic clock according to claim 4, wherein The Pt100 temperature sensor resistor (1) is used to monitor the temperature of the upper groove (3) in real time and transmit the temperature information to the controller. The controller controls whether the PTC heating sheet (2) works according to the temperature information; the controller controls the semiconductor refrigerator (6) and the water cooling plate (7) to generate a refrigeration effect, which is used to dissipate heat from the lower part of the chip atomic clock during the getter activation process.

6. The getter activation device for a vacuum-packaged chip atomic clock according to claim 5, wherein, The PTC heating sheet (2) is attached to the top of the upper groove (3) with silicone grease during use; the heat dissipation surface of the semiconductor refrigerator (6) is attached to the water cooling plate (7) with silicone grease, and the bottom of the lower groove (5) is attached to the refrigeration surface of the semiconductor refrigerator (6) with silicone grease.

7. The getter activation device for a vacuum-packaged chip atomic clock according to claim 1, characterized in that, The water cooling plate (7) is provided with a water inlet (7-1) and a water outlet (7-2). When the water cooling plate (7) starts to work, cooling water enters the water cooling plate (7) through the water inlet (7-1) and flows out through the water outlet (7-2) for circulating heat dissipation.

8. A method for using the getter activation device of the vacuum-packaged chip atomic clock according to any one of claims 1-7, characterized in that, The usage method includes the following steps: S1. Place the packaged chip atomic clock (4) into the lower groove (5) of the getter activation device, and then cover the upper groove (3) on the chip atomic clock (4), ensuring that the upper groove (3) and the lower groove (5) do not touch; S2. The controller controls the PTC heating sheet (2) to electrically heat, so that the upper groove (3) quickly heats up. The Pt100 temperature sensor resistor (1) monitors the temperature of the upper groove (3) in real time and transmits the temperature information to the controller. When the Pt100 temperature sensor resistor (1) monitors that the temperature reaches the optimal activation temperature of the getter, the controller controls the PTC heating sheet (2) to keep the temperature of the upper groove (3) maintained at the optimal activation temperature for a period of time to ensure that the getter on the inner wall of the ceramic cap (4-1) is fully activated; S3. Meanwhile, the controller controls the semiconductor refrigerator (6) to generate a refrigeration effect and simultaneously controls the water-cooled plate (7) to start working. The refrigerating surface of the semiconductor refrigerator (6) absorbs the heat from the lower part of the chip atomic clock (4), and transfers the heat to the water-cooled plate (7) through the heat dissipation surface of the semiconductor refrigerator (6), so as to ensure that the In 0.97 Ag 0.03 welding ring (4-3) will not melt due to overheating; S4. After the heat preservation is completed, the controller first controls the PTC heating sheet (2) to stop working. When the Pt100 temperature sensing resistor (1) monitors that the temperature of the upper groove (3) is lower than the melting point of the welding ring material, the controller controls the semiconductor refrigerator (6) and the water cooling plate (7) to stop working; S5. Remove the upper groove (3) from the chip atomic clock (4) and take out the chip atomic clock (4) for which the getter activation has been completed.

9. The method of using the getter activation device according to claim 8, characterized in that, In the step S2, the heat preservation time of the upper groove (3) is thirty minutes.

10. The method of using the getter activation device according to claim 8, characterized in that, The optimal activation temperature of the getter in step S2 is 300 °C, and the melting point of the solder ring material in step S4, that is, In 0.97 Ag 0.03 The melting point of the material is 143 °C.

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