High-temperature-resistant thermosensitive crystal resonator without sealing cover

Abstract

The invention relates to a high-temperature-resistant thermosensitive crystal resonator without a sealing cover, which comprises a lower base, a quartz chip and a thermistor, an upper base is arranged at the upper end of the lower base, the middle part of the upper end of the lower base and the middle part of the lower end of the upper base are respectively provided with a groove, and the two grooves are butted up and down to form an inner cavity; a quartz chip is installed in the lower groove, a thermistor is installed in the upper groove, and external electrodes connected with the quartz chip and the thermistor in a one-to-one correspondence mode are arranged at the lower end of the lower base. The upper base is used for replacing a metal upper cover for sealing, so that the thermal stress of the thermosensitive crystal resonator is effectively reduced, the problem that gold-tin alloy overflows due to packaging of a traditional metal upper cover is solved, meanwhile, the sealing performance of the resonator is improved, and accurate real-time temperature signals can be provided; the purpose of stable work in a high-temperature environment is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of quartz crystal frequency components, in particular to a high-temperature resistant thermistor crystal resonator without a sealing cover. Background Art

[0002] Thermistor crystal resonator is usually composed of piezoelectric quartz chip, thermistor, conductive glue, ceramic base and metal cover. The piezoelectric quartz chip is usually rectangular or circular. The ceramic base usually needs to sacrifice a part of the area of ​​​​the spot tin pad on the back to reserve a groove for placing the thermistor. The piezoelectric quartz chip is plated with electrodes on the upper and lower sides and fixed in the package shell by conductive glue. The electrodes are connected to the base pins of the package shell through the leads of the sealed package. The AC voltage is connected to the upper and lower electrodes of the quartz chip through the pins, causing the quartz chip to produce an inverse piezoelectric effect, thereby generating oscillation. At the same time, the thermistor senses the surrounding temperature and transmits the temperature signal to the IC. The IC adjusts the frequency output of the crystal oscillation circuit in time through the internal circuit to stabilize it within a controllable range.

[0003] With the continuous development of microelectronic products, stringent requirements are also put forward for thermistor crystal resonators. First of all, the ceramic base and the metal cover are made of different materials, which will generate large thermal stress during the thermal process. At the same time, due to the structure of the metal cover, overflow of gold-tin alloy will occur during packaging, causing the risk of short circuit; secondly, the chip is fixed on the base by conductive glue. With the miniaturization of glue points, the conductive particles in the conductive glue are also getting smaller, and the smaller conductive particles cannot play a better supporting effect, resulting in high instability of chip mounting, and the glue thickness between the quartz chip and the glue pad fluctuates; finally, the thermistor and the quartz chip are designed separately in different grooves, which makes the thermistor sense the temperature and the quartz chip with a certain hysteresis, and the area of ​​the tin pad is sacrificed for the groove design, resulting in poor welding strength. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a high-temperature resistant thermistor crystal resonator without a sealing cover, which can reduce the thermal stress of the thermistor crystal resonator and improve the impact resistance of the resonator. At the same time, it completely solves the overflow problem in the gold-tin alloy and can provide accurate real-time temperature signals, so as to achieve the purpose of stable operation in harsh temperature environments.

[0005] The technical solution adopted by the present invention to solve its technical problem is: to provide a high-temperature resistant thermistor crystal resonator without a sealing cover, comprising a lower base, a quartz chip and a thermistor, wherein an upper base is installed at the upper end of the lower base, a groove is provided in the middle of the upper end of the lower base and in the middle of the lower end of the upper base, the two grooves are butted up and down to form an inner cavity, a quartz chip is installed in the lower groove, a thermistor is installed in the upper groove, and an external electrode connected to the quartz chip and the thermistor in a one-to-one correspondence is provided at the lower end of the lower base.

[0006] As a supplement to the technical solution described in the present invention, the upper end of the lower base is located inside the groove and has two glue-dispensing pads arranged in parallel, and the quartz chip is fixed on the glue-dispensing pads by conductive glue.

[0007] As a supplement to the technical solution described in the present invention, a support portion is provided in the middle of the upper end of each glue pad, and the support portion is an isosceles trapezoidal block structure, and the width of the support portion gradually increases from top to bottom. The conductive glue has a plurality of conductive particles inside, and the conductive particles and the support portion jointly support the quartz chip, and the glue thickness between the quartz chip and the glue pad is 13um~15um.

[0008] As a supplement to the technical solution described in the present invention, the lower end of the upper base is located inside the groove and has two tin pads arranged side by side. The thermistor is mounted on the two tin pads through solder paste, and the two tin pads are respectively connected to the corresponding external electrodes.

[0009] As a supplement to the technical solution described in the present invention, the upper base is provided with upper conductive holes connected one-to-one with the two tin soldering pads, and the lower base is provided with lower conductive holes for connecting the upper conductive holes and the external electrodes. The upper conductive holes and the lower conductive holes are filled with conductive materials, and the two tin soldering pads are connected to the corresponding external electrodes through the conductive materials in the upper conductive holes and the conductive materials in the lower conductive holes.

[0010] As a supplement to the technical solution described in the present invention, the lower base and the upper base are sealed by a gold-tin alloy.

[0011] As a supplement to the technical solution described in the present invention, a circle of convex rings is arranged around the inner side of the groove opening at the lower end of the upper base, and the convex rings and the end face of the upper base form a step structure. The upper end face of the lower base is provided with a boss structure inserted into the corresponding convex ring.

[0012] As a supplement to the technical solution described in the present invention, the distance between the thermistor and the quartz chip ranges from 60um to 90um.

[0013] As a supplement to the technical solution described in the present invention, the upper and lower surfaces of the quartz chip are both covered with an electrode surface, which overlaps with the upper surface or the lower surface of the quartz chip to form a main vibration area, and the two electrode surfaces are respectively connected to corresponding external electrodes.

[0014] Beneficial effects: The present invention relates to a high-temperature resistant thermistor crystal resonator without a sealing cover. The upper base is used to replace the traditional metal upper cover for sealing, which can effectively reduce the thermal stress of the product, greatly improve the high-temperature resistance of the thermistor crystal resonator, and meet the customer's demanding use environment; at the same time, the upper base is provided with a convex ring around the inner side of the groove opening to prevent the internal overflow of the gold-tin alloy, which solves the problem of internal overflow of the gold-tin alloy caused by the traditional metal upper cover, and completely solves the problem of short circuit caused by internal overflow of the gold-tin alloy; the support part on the dispensing pad is matched with the conductive particles in the conductive glue to effectively control the glue thickness between the quartz chip and the dispensing pad, thereby improving the impact resistance of the product; by The thermistor and quartz chip are designed in the same cavity, which can accurately measure the real-time temperature of the quartz chip and provide accurate temperature data for IC compensation; through the optimization of the lower base and the upper base structure, the lower end surface of the upper base is designed to be a step structure, and the lower base is designed with a boss structure matching the step structure, which can effectively improve the positioning accuracy between the lower base and the upper base and improve their welding strength; by separately designing the quartz chip groove and the thermistor groove, the existing series production process of first carrying the quartz chip and then carrying the thermistor is optimized to a parallel production process of carrying the quartz chip and the thermistor at the same time, which effectively shortens the product production cycle and increases the efficiency of production capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a cross-sectional view of the main viewing direction of the present invention; Figure 2 is a top view of the lower base of the present invention; Figure 3 is a top view of the upper base of the present invention; Figure 4 The present invention Figure 1 A partial enlarged view of middle A; Figure 5 It is a bottom view of the lower base of the present invention.

[0016] Illustration: 1. Lower base, 2. Glue pad, 3. Support part, 4. Lower conductive hole, 5. Boss structure, 6. External electrode, 7. Conductive glue, 8. Conductive particles, 9. Quartz chip, 10. Electrode surface, 11. Upper base, 12. Tin pad, 13. Upper conductive hole, 14. Boss ring, 15. Solder paste, 16. Thermistor, 17. Gold-tin alloy, 18. Inner cavity. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0018] The embodiment of the present invention relates to a high temperature resistant thermosensitive crystal resonator without a sealing cover, such as Figure 1-5 As shown, it includes a lower base 1, a quartz chip 9 and a thermistor 16. The upper end of the lower base 1 is installed with an upper base 11. A groove is provided in the middle of the upper end of the lower base 1 and the middle of the lower end of the upper base 11. The two grooves are connected up and down to form an inner cavity 18. The quartz chip 9 is installed in the lower groove, and the thermistor 16 is installed in the upper groove. The lower end of the lower base 1 is provided with an external electrode 6 connected to the quartz chip 9 and the thermistor 16 in a one-to-one correspondence. The lower base 1 and the upper base 11 are sealed together by a gold-tin alloy 17 to replace the traditional metal cover. The thermal stress generated by the product after the thermal process mainly comes from the heterogeneous materials, which can effectively reduce the thermal stress of the product.

[0019] The conventional quartz chip 9 is fixed on the glue pad 2 by the conductive glue 7. Affected by the structure, the glue thickness between the quartz chip 9 and the glue pad 2 can only be controlled by the conductive particles 8 in the conductive glue 7. However, with the miniaturization of the product, the particle size of the conductive particles 8 is also constantly miniaturized. The smaller conductive particles 8 cannot play a better supporting effect, which will cause the glue thickness between the quartz chip 9 and the glue pad 2 to be smaller, and it will not play a good buffering role when the product is impacted by external force, which will eventually lead to a large change in RR when subjected to mechanical impact. The upper end of the lower base 1 of the present invention is located inside the groove and has two Glue dispensing pad 2, the quartz chip 9 is fixed on the glue dispensing pad 2 by conductive glue 7, and a support part 3 is provided in the middle of the upper end of each glue dispensing pad 2. A support part 3 is designed on the glue dispensing pad 2. The advantage of this is that the mounting of the quartz chip 9 can be completely controlled according to the height of the support part 3 and the particle size of the conductive particles 8, ensuring that the glue thickness between the quartz chip 9 and the glue dispensing pad 2 is 13um~15um. When the product is subjected to mechanical impact, the conductive glue 7 can play a good buffering role, reduce internal stress, effectively reduce the RR change during impact, and greatly improve the stability of the product's conductivity and impact resistance.

[0020] As a preferred embodiment of the support portion 3, the support portion 3 is an isosceles trapezoidal block structure, and the width of the support portion 3 gradually increases from one end of the support portion 3 connected to the conductive glue 7 to the other end of the support portion 3 connected to the glue pad 2. Such a shape design of the support portion 3 can increase the contact area with the conductive glue 7, thereby effectively improving the bonding strength of the quartz chip 9.

[0021] As an illustration of the installation method of the thermistor 16, the lower end of the upper base 11 is located inside the groove and has two tin pads 12 arranged side by side. The thermistor 16 is mounted on the two tin pads 12 through solder paste 15, and the two tin pads 12 are respectively connected to the corresponding external electrodes 6; the upper base 11 is provided with an upper conductive hole 13 connected one-to-one with the two tin pads 12, and the lower base 1 is provided with a lower conductive hole 4 for connecting the upper conductive hole 13 with the external electrode 6. The upper conductive hole 13 and the lower conductive hole 4 are filled with conductive material. When the lower base 1 and the upper base 11 are sealed, the two tin pads 12 are respectively connected to the corresponding external electrodes 6 through the conductive material in the upper conductive hole 13 and the conductive material in the lower conductive hole 4, thereby realizing circuit conduction between the thermistor 16 and the external electrode 6.

[0022] As an installation instruction for the lower base 1 and the upper base 11, a convex ring 14 is provided at the lower end of the upper base 11 around the inner side of the groove opening, and the convex ring 14 forms a step structure with the open end face of the upper base 11. The upper end of the lower base 1 is provided with a boss structure 5 inserted into the corresponding convex ring 14; the lower base 1 and the upper base 11 are sealed by a gold-tin alloy 17; high-precision positioning is achieved by the combination of the boss structure 5 and the step structure, and this structure can also improve the welding strength, and after positioning, the gold-tin alloy 17 is used to achieve The convex ring 14 can prevent the gold-tin alloy 17 from overflowing when sealing; the height of the gold-tin alloy 17 is 8~10um; the thickness of the lower base 1 is 0.22~0.24mm; the thickness of the upper base 11 is 0.25~0.27mm, and the total thickness of the resonator is 0.46~0.48mm; the boss structure 5 cooperates with the step structure to avoid the short circuit problem between the conductive material of the lower conductive hole 4 and the gold-tin alloy 17 when the lower base 1 and the upper base 11 are sealed.

[0023] As an explanation of the setting of the thermistor 16 and the quartz chip 9, the spacing between the thermistor 16 and the quartz chip 9 is in the range of 60um to 90um. Within this spacing range, the real-time temperature signal of the sensing quartz chip 9 can be relatively close. At the same time, the thermistor is sealed in the cavity to reduce the damage of the external environment to the thermistor 16 and the solder paste 15.

[0024] The upper and lower surfaces of the quartz chip 9 are both covered with an electrode surface 10 , which overlaps with the upper or lower surface of the quartz chip 9 to form a main vibration area. The two electrode surfaces 10 are connected to the corresponding external electrodes 6 , respectively.

[0025] On the one hand, the present invention separately designs the groove for carrying the quartz chip and the groove for carrying the thermistor into independent lower base 1 and upper base 11. The upper base 11 replaces the traditional metal upper cover to play a sealing role and greatly reduces the thermal stress of the product. At the same time, the upper base 11 is provided with a circle of convex ring 14 around the inner side of the groove opening, which can effectively prevent the problem of internal overflow of the gold-tin alloy 17 during packaging. By separately designing the lower base 1 and the upper base 11, in the assembly process of the product, the process of fixing the quartz chip 9 on the lower base 1 and the process of fixing the thermistor 16 on the upper base 11 can be carried out simultaneously, which greatly shortens the production cycle and improves the production efficiency. On the other hand, by designing the support part 3 on the glue pad 2 and matching the conductive particles 8 in the conductive glue 7, the glue thickness between the quartz chip 9 and the glue pad 2 is effectively controlled, thereby improving the impact resistance of the product. At the same time, the thermistor 16 and the quartz chip 9 are designed in the same cavity. Such a setting can accurately obtain the real-time temperature signal of the quartz chip 9, and provide an accurate temperature signal for the IC to achieve the effect of accurate compensation. In summary, the present invention can reduce the thermal stress of the thermistor crystal resonator, improve the impact resistance of the resonator, and at the same time completely solve the overflow problem in the gold-tin alloy and provide accurate real-time temperature signals, so as to achieve the purpose of stable operation in a high temperature environment.

[0026] As an explanation of the separate arrangement of the upper base 11 and the lower base 1, the base structure of the traditional thermistor crystal resonator is H-shaped, with two grooves formed on the upper and lower sides for carrying the quartz chip and the thermistor. The groove for carrying the quartz chip is sealed with a metal upper cover, and the groove for carrying the thermistor is exposed. At the same time, the external electrode is arranged around the end face of the thermistor groove. Affected by the thermistor groove, the external electrode area is small, which will reduce the welding strength between the product and the PCB board; the advantages of designing the upper base 11 and the lower base 1 separately are: first, the upper base 11 replaces the metal upper cover to achieve sealing, and at the same time greatly reduces thermal stress; second, the thermistor 16 is arranged inside the cavity to improve the sealing of the product; third, the external electrode 6 is designed on the bottom platform of the lower base 1, the area of ​​the external electrode 6 is increased, and the welding strength between the product and the PCB board is effectively improved; fourth, the series production process of first carrying the quartz chip 9 and then carrying the thermistor 16 is optimized to a parallel production process of carrying the quartz chip 9 and carrying the thermistor 16 synchronously, which greatly shortens the production cycle and improves production efficiency.

[0027] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0028] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0029] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0030] The above is a detailed introduction to a high-temperature resistant thermistor crystal resonator without a sealing cover provided by the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A high temperature resistant thermistor crystal resonator without a sealing cover, comprising a lower base (1), a quartz chip (9) and a thermistor (16), characterized in that: An upper base (11) is mounted on the upper end of the lower base (1), a groove is provided in the middle of the upper end of the lower base (1) and the middle of the lower end of the upper base (11), the two grooves are connected up and down to form an inner cavity (18), a quartz chip (9) is installed in the lower groove, and a thermistor (16) is installed in the upper groove, and an external electrode (6) connected to the quartz chip (9) and the thermistor (16) in a one-to-one correspondence is provided at the lower end of the lower base (1).

2. The high temperature resistant thermistor crystal resonator without sealing cover according to claim 1, characterized in that: The upper end of the lower base (1) is located inside the groove and has two glue-dispensing pads (2) arranged in parallel. The quartz chip (9) is fixed on the glue-dispensing pads (2) by means of conductive glue (7).

3. The high temperature resistant thermistor crystal resonator without sealing cover according to claim 2, characterized in that: A support portion (3) is provided in the middle of the upper end of each glue dispensing pad (2); the support portion (3) is an isosceles trapezoidal block structure, and the width of the support portion (3) gradually increases from top to bottom.

4. The high temperature resistant thermistor crystal resonator without sealing cover according to claim 2, characterized in that: The glue thickness between the quartz chip (9) and the glue pad (2) is 13um-15um.

5. The high temperature resistant thermistor without sealing cover according to claim 1, characterized in that: The lower end of the upper base (11) is located inside the groove and has two tin pads (12) arranged side by side. The thermistor (16) is mounted on the two tin pads (12) via solder paste (15). The two tin pads (12) are respectively connected to corresponding external electrodes (6).

6. The high temperature resistant thermistor crystal resonator without sealing cover according to claim 5, characterized in that: The upper base (11) is provided with an upper conductive hole (13) connected to the two spot tin soldering pads (12) in a one-to-one correspondence, and the lower base (1) is provided with a lower conductive hole (4) for connecting the upper conductive hole (13) and the external electrode (6). The upper conductive hole (13) and the lower conductive hole (4) are filled with conductive material, and the two spot tin soldering pads (12) are connected to the corresponding external electrode (6) through the conductive material in the upper conductive hole (13) and the conductive material in the lower conductive hole (4).

7. The high temperature resistant thermistor crystal resonator without sealing cover according to claim 1, characterized in that: The lower base (1) and the upper base (11) are sealed by a gold-tin alloy (17).

8. A high temperature resistant thermosensitive crystal resonator without sealing cover according to claim 1 or 7, characterized in that: A convex ring (14) is arranged on the inner side of the groove opening around the lower end of the upper base (11), and the convex ring (14) and the end surface of the upper base (11) form a stepped structure. The upper end surface of the lower base (1) is provided with a boss structure (5) inserted into the corresponding convex ring (14).

9. The high temperature resistant thermistor crystal resonator without sealing cover according to claim 1, characterized in that: The distance between the thermistor (16) and the quartz chip (9) ranges from 60 um to 90 um.

10. The high temperature resistant thermistor crystal resonator without sealing cover according to claim 1, characterized in that: The upper and lower surfaces of the quartz chip (9) are both coated with a layer of electrode surface (10), and the electrode surface (10) overlaps with the upper surface or the lower surface of the quartz chip (9) to form a main vibration area. The two electrode surfaces (10) are respectively connected to corresponding external electrodes (6).

Images