TWI422080B - Enhanced gas - tightness of the oscillator device wafer - level package structure - Google Patents

Description

Enhanced airtight vibrator device wafer level package structure

The invention relates to a vibrator device, which is applied to various electronic products such as mobile phones, notebook computers, automobile electronics, etc., in particular to a wafer level packaging structure of a vibrator device for enhancing airtightness.

Quartz components have stable piezoelectric characteristics, providing accurate and wide reference frequency, clock control, timing functions and filtering noise. In addition, quartz components can also be used as sensors for motion and pressure, as well as important Optical components; therefore, for electronic products, quartz components play a pivotal role.

For the encapsulation of quartz crystal oscillator crystals, many proposals have been made in the prior art, such as the "sacrificial quartz-crystal mount" of the US Patent Publication No. 5030875, which belongs to the early metal cap (Metal Cap). The package method has a complicated package structure and cannot be reduced in size. U.S. Patent No. 6,654,392, "Package structure for a piezoelectric resonator", which mainly uses a ceramic package to encapsulate a quartz tuning fork vibrator, and improves the ceramic package and the lid structure. Therefore, the quartz tuning fork vibrator has better shock resistance, however, the package is costly and the size cannot be further reduced.

U.S. Patent No. 6,531,807, "Piezoelectric Device", which is mainly used for encapsulating a quartz crystal oscillator and an oscillating circuit chip on ceramic pedestals in different regions, and electrically connecting the wires on the ceramic pedestal while oscillating The circuit chip is packaged in resin, and the quartz vibrator is covered by the above cover; however, since the two wafers are placed in different blocks and the ceramic base is used as the package, the area is increased and the manufacturing cost is high. No less.

In addition, the "Piezoelectric Oscillator" of the Japanese Patent Publication No. 7098580, which mainly encapsulates a quartz wafer and an integrated circuit in a ceramic package, and then performs an electrical connection operation, can effectively reduce the area problem. However, the overall volume cannot be effectively reduced, and the manufacturing cost of the packaging method is relatively high.

The US Patent Publication No. 7608986 "Quartz crystal resonator" is mainly a wafer-level package form, which mainly uses a blue plate glass upper cover and a lower base, and a quartz wafer. Anode bonding completes a sandwich structure. However, this sandwich structure differs in thermal expansion coefficient between the substrate and the quartz, so that when the temperature changes, the internal quartz wafer generates thermal stress, so that the frequency shifts with temperature. Therefore, it is necessary to specifically select the chamfer angle of the quartz wafer and the thermal expansion coefficient of the upper and lower base materials in order to overcome this difficulty, but it is laborious in terms of production and cost.

The prior art of the above patents cannot escape the current dilemma of using a ceramic pedestal package, which not only has high product cost and unstable supply, but also the thermal stress problem caused by the sandwich-like package structure cannot be effectively solved.

In view of the above problems, the main object of the present invention is to provide a wafer-level package structure of a vibrator device which is enhanced in airtightness, which is suitable for the current use of a ceramic base package, which has reduced product cost and stable supply, and improves the sandwich package structure. The thermal stress problem caused by the through-hole connection method enables the process to be batch-produced and complete packaged on the wafer. At the same time, the groove-like package ring structure design, in addition to assisting the alignment, has a metal joint. The combination of anodic bonding and oxidative bonding regions enhances the strength and airtightness of the package and increases the reliability of the product.

Therefore, in order to achieve the above object, a wafer level package structure of a vibrator device for enhancing airtightness disclosed in the present invention includes a vibrator unit, an upper cover, a base, a package ring groove, and a conductive through hole, and the vibrator unit is disposed at the base. a socket, and the package ring groove is disposed adjacent to the outer edge of the base, and the base ring is provided in the package ring groove for engaging the cover ring of the upper cover and covering the vibrator unit, and sealing the air unit. The conductive via extends vertically through the pedestal and is electrically connected to the vibrator unit to provide signal output/input of the vibrator unit. Therefore, by vertically penetrating through the conductive vias, the length of the connection lines is reduced, thereby reducing the parasitic capacitance/inductance effect caused by the high frequency; and at the same time, the design of the package ring groove and the upper cover package ring and the base package ring In addition to assisting the alignment, it also cooperates with the joint area of the upper cover and the base, and can provide various joint areas, strengthen the strength and airtightness of the package, and increase the reliability of the product; on the other hand, the upper cover ring and the cover After the pedestal encapsulation ring is joined, the pedestal and the edge of the upper cover form a complete plane, reducing the accumulation of contaminants.

In order to further understand the purpose, features and functions of the present invention, the drawings are described in detail as follows:

According to the wafer level packaging structure of the vibrator device for enhancing airtightness disclosed in the present invention, first, referring to FIGS. 1A and 1B, FIG. 1 is a schematic view showing a first embodiment of a wafer level package structure of a vibrator device for enhancing airtightness according to the present invention.

The vibrator device of the enhanced airtightness according to the present invention includes a vibrator unit 20, an upper cover 10, a base 40, a package ring groove 30, and a conductive via 50. The vibrator unit 20 can be a temperature stable chamfer. (AT-cut) a quartz crystal vibrator such as a quartz crystal vibrator or a tuning fork quartz crystal vibrator or other mechanical resonance type vibrator, and the upper surface and the lower surface of the vibrator unit 20 have an upper surface electrode 21 and a lower surface electrode 22, respectively (see FIG. 2) Therefore, the vibrator unit 20 is excited and electrically connected to the base metal pad 41 of the bottom base 40 through the conductive bumps 23. The upper surface electrode 21 and the lower surface electrode 22 are respectively located on opposite sides of the vibrator unit 20, and the conductive bumps 23 may be conductive rubber materials or metal bumps composed of silver powder particles and resin, wherein the metal bumps may be gold or copper. One of tin, silver, indium or one of its alloys.

Therefore, the vibrator unit 20 is disposed on the base 40, and the package ring groove 30 is disposed adjacent to the outer edge of the base 40, the base ring 32 is provided in the package ring groove 30, and the upper cover 10 has a corresponding upper cover ring. 31; the upper cover ring 31 and the base package ring 32 may be made of copper, tin, gold, silver, indium, and an alloy of the above metals, an organic polymer, an oxide or the like; if the upper cover ring 31 and the base package The ring 32 is made of metal, and if the upper cover 10 and the base 40 are electrically conductive, a layer of insulation must be provided between the two to prevent the upper cover 10 and the base 40 from being electrically connected. Therefore, the function of the alignment can be provided by the design of the package ring groove 30 and the upper cover package ring 31. The upper cover package ring 31 is inserted into the package ring groove 30 and engaged with the base package ring 32, and the upper cover 10 has The recess 11 accommodates the vibrator unit 20 and provides a package for the vibrator assembly. Therefore, the upper cover 10 and the base 40 are transmitted through the package ring groove 30, the upper cover ring 31 and the base package ring 32, and the vibrator unit 20 can be hermetically sealed, and the internal environment can be vacuum or filled with nitrogen; The material may be bismuth, glass, quartz, ceramic, metal material, etc. The material of the susceptor 40 may also be non-conductive materials such as enamel, glass, quartz, ceramic, etc., and if both are used (top cover 10 and pedestal 40) The same material is used to further prevent thermal stress.

At the same time, after the upper cover ring 31 is engaged with the base package ring 32, the upper cover 10 and the edge of the base 40 are closely combined and aligned to form a complete plane to reduce the accumulation of contaminants.

The conductive vias 50 are vertically disposed through the susceptor 40 and may be made of a metal conductive material such as copper, tungsten, aluminum, silver, gold, or an alloy of the above metals. Alternatively, the conductive vias 50 may be polysilicon or conductive. Molecules, as long as they can conduct electricity, are formed by using a through silicon via (TSV) technique. The conductive via 50 is electrically connected to the upper surface electrode 21 and the lower surface electrode 22 of the vibrator unit 20, and is electrically connected to the pedestal metal pad 41 so as to be electrically connected to the outside to provide electrical energy. Signal input and output.

Wherein, when the upper cover ring 31 and the base package ring 32 are alloys of copper, tin, gold, silver, indium and the above metal, they may be bonded by means of metal fusion bonding or thermal-compression bonding. When the upper cover ring 31 and the base package ring 32 are organic polymers, the package can be achieved by a bonding technique; and when the upper cover ring 31 and the base package ring 32 are made of an oxidizing material such as cerium oxide, The package can be achieved by anodic bonding. At the same time, when the upper cover ring 31 is engaged with the base package ring 32, the contact faces of the base 40 and the upper cover 10 are simultaneously joined. When the base 40 and the upper cover 10 are made of enamel, quartz and glass, the anodic bonding is possible. The technology is bonded; when the susceptor 40 and the upper cover 10 are made of bismuth oxide or the like, they can be joined by an oxide bonding technique; when the susceptor 40 is made of a ceramic material and the upper cover 10 is made of a metal material, it is permeable. Metal fusion technology is used to join the completed package. Therefore, the package structure has multiple joint areas such as the upper cover 10, the base 40, and the upper cover package ring 31 and the base package ring 32, thereby enhancing the strength and airtightness of the package and increasing the reliability of the product. Further, when the base package ring 32 is made of a metal having a low melting point, when it is welded to the upper cover ring 31, a fusion coating effect or a metal eutectic bonding can be produced, thereby increasing the package strength and airtightness.

On the other hand, in addition to the above-described upper surface electrode 21 and lower surface electrode 22 being located on opposite sides of the vibrator unit 20, they may be designed to be located on the same side. Please refer to FIG. 3 , which is a schematic diagram of a second embodiment of a wafer level package structure of a vibrator device for enhancing airtightness according to the present invention; wherein the upper surface electrode 21 and the lower surface electrode 22 are located on the same side of the vibrator unit 20 (see Figure 4).

Similarly, the recess 11 of the upper cover 10 is designed to accommodate the vibrator unit 20, so that the base 40 can also be designed with a recess 42 and the upper cover 10 is designed to be flat, and the same effect can be achieved. 5A, 5B, respectively, corresponding to the first embodiment and the second embodiment; in this case, the inner edge of the package ring 30 is cut at the edge of the groove 42 of the base 40, too, It can also serve as a mask for forming the recess 42 of the susceptor 40.

The wafer-level package structure of the vibrator device for enhancing airtightness disclosed in the present invention electrically connects the vibrator unit to the base metal pad of the bottom portion by vertically penetrating through the conductive via hole opened in the base. The current dip environment of ceramic base package (including high product cost and unstable supply), and improve the thermal stress caused by the sandwich package structure; at the same time, reduce the use of precious metal materials and further shrinkage, reduce the connection line Length, thereby reducing parasitic capacitance/inductance effects due to high frequency. And through the wafer bonding technology, quartz crystal oscillators can be batch-produced, reducing labor and production time and reducing production costs. At the same time, the package ring groove and the upper cover package ring have the concave-convex auxiliary positioning effect, which increases the reliability of the positioning when the package is packaged; at the same time, the design of the package ring groove makes it not overflow due to the liquid package ring material during the packaging process. Furthermore, the upper cover, the base, and the multiple joint areas such as the upper cover package ring and the base package ring enhance the strength and airtightness of the package and increase the reliability of the product; and the upper cover ring and the base package ring After joining, the upper cover is closely combined with the edge of the base to form a complete plane to reduce the accumulation of contaminants.

Although the present invention has been disclosed above in the foregoing embodiments, it is not intended to limit the invention. It is within the scope of the invention to be modified and modified without departing from the spirit and scope of the invention. Please refer to the attached patent application for the scope of protection defined by the present invention.

10. . . Upper cover

11. . . Groove

20. . . Vibrator unit

twenty one. . . Upper surface electrode

twenty two. . . Lower surface electrode

twenty three. . . Conductive bump

30. . . Package ring groove

31. . . Top cover ring

32. . . Base package ring

40. . . Pedestal

41. . . Base metal pad

42. . . Groove

50. . . Conductive through hole

1A and 1B are schematic views showing a first embodiment of a wafer level package structure of a vibrator device for enhancing airtightness according to the present invention.

2 is a schematic view showing the upper and lower electrodes of the vibrator unit in the first embodiment of the wafer level package structure of the vibrator device for enhancing airtightness according to the present invention.

Fig. 3 is a schematic view showing a second embodiment of the wafer level package structure of the vibrator device for enhancing airtightness according to the present invention.

4 is a schematic view showing the upper and lower electrodes of the vibrator unit in the second embodiment of the wafer level package structure of the vibrator device for enhancing airtightness according to the present invention.

FIG. 5A is a schematic view showing a variation of the groove in the first embodiment of the wafer level package structure of the vibrator device for enhancing airtightness according to the present invention.

FIG. 5B is a schematic view showing a variation of the groove in the second embodiment of the wafer level package structure of the vibrator device for enhancing airtightness according to the present invention.

10. . . Upper cover

11. . . Groove

20. . . Vibrator unit

twenty one. . . Upper surface electrode

twenty two. . . Lower surface electrode

twenty three. . . Conductive bump

30. . . Package ring groove

31. . . Top cover ring

32. . . Base package ring

40. . . Pedestal

41. . . Base metal pad

50. . . Conductive through hole

Claims (10)

A wafer-level package structure for enhancing a gas-tight vibrator device, comprising: a vibrator unit; a base for the vibrator unit; a package ring groove disposed on the base and adjacent to the base An edge of the package ring is provided with a base encapsulation ring; an upper cover is disposed on the base and is disposed on the vibrator unit, and the vibrator unit is packaged, and an upper cover encapsulation ring is disposed on the bottom of the upper cover. Corresponding to the package ring groove and engaging with the base package ring; and at least one conductive through hole vertically disposed on the base and electrically connected to the vibrator unit to provide signal input/output. The wafer-level package structure of the vibrator device for enhancing airtightness according to claim 1, wherein the vibrator unit is a quartz crystal vibrator or a mechanical resonance type vibrator, and the quartz crystal vibrator is a temperature stable chamfer. (AT-cut) Quartz crystal vibrator or tuning fork type quartz crystal vibrator. The wafer-level package structure of the vibrator device for enhancing airtightness according to claim 1, wherein the upper cover is composed of one of bismuth, glass, quartz, ceramic or metal material, and the upper cover ring and the base The encapsulation ring is composed of one of materials of copper, tin, gold, silver, indium or the above alloy, organic polymer or oxide, and the base is composed of one of bismuth, glass, quartz or ceramic materials, and the The conductive vias are selected from the group consisting of copper, silver, gold, tungsten, or alloys thereof. The wafer-level package structure of the vibrator device for enhancing airtightness according to claim 1, wherein the vibrator unit comprises an upper surface electrode and a lower surface electrode, wherein the upper surface electrode and the lower surface electrode system are respectively A conductive bump is electrically connected to the conductive via, and the conductive bump is formed by one of a mixed conductive paste or a metal bump of silver powder particles and a resin, and the metal bump may be made of gold, copper, tin or silver. One of, indium or one of its alloys. The vibrator device wafer level package structure of claim 4, wherein the upper surface electrode and the lower surface electrode are disposed on the same side or opposite sides of the vibrator unit. The wafer-level package structure of the vibrator device for enhancing airtightness according to the first aspect of the invention, wherein the upper cover has a recess for accommodating the vibrator unit. The wafer-level package structure of the vibrator device for enhancing airtightness according to claim 1, wherein the base has a recess for accommodating the vibrator unit. The wafer-level package structure of the vibrator device for enhancing airtightness according to claim 1, wherein the conductive via is formed by a via via technology. The wafer-level package structure of the vibrator device according to claim 1, wherein the bottom of the base further comprises a base metal pad for electrically connecting to the conductive via. The wafer-level package structure of the vibrator device according to claim 1, wherein the upper cover and the base package ring are joined to each other, and the upper cover is closely combined with the edge of the base. .