TWI412167B - Modified oscillator wafer level package structure - Google Patents

Abstract

An improved oscillator wafer level package structure, mainly includes a cover, resonating unit, base, package ring and a conductive via, package ring disposed between the base and the cover, and between the top cover and a base for combining the resonating unit where hermetic mounted on the base, via vertical penetrates the base and resonating unit is electrically connected, to provide a resonating unit of the signal output / input, package ring and the outer edge of the base and a cover, alignment, cut to form a complete plane without the trench for avoiding deposit of contaminants.

Description

Improved vibrator 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 an improved vibrator wafer level package structure.

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 an improved vibrator wafer level package structure, which is currently in a ceramic substrate package, which has reduced product cost and stable supply, and improves thermal stress caused by the sandwich package structure. The problem is that the through-hole connection method allows the process to be batch-produced and complete packaged on the wafer; at the same time, the accumulation of contaminants is greatly reduced by the design of the rim-free planar surface.

Therefore, in order to achieve the above object, an improved vibrator wafer level package structure disclosed in the present invention includes a vibrator unit, an upper cover, a base, a package ring, and a conductive via, the vibrator unit is disposed on the base, and the package is The ring is disposed on the outer edge of the base, the upper cover is disposed to cover the vibrator unit, and the vibrator unit is hermetically sealed, and the conductive through hole vertically penetrates the base and is electrically connected to the vibrator unit, and provides 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 due to high frequency; and at the same time, by the outer edge of the package ring being aligned with the upper cover and the pedestal, A complete groove-free plane is formed to reduce the accumulation of contaminants; and the encapsulation ring is aligned with the edge of the upper cover or the groove of the base, which increases the area of the encapsulation ring and improves the joint strength and sealing effect.

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 improved vibrator wafer level package structure disclosed in the present invention, first, referring to FIG. 1 , it is a schematic diagram of a first embodiment of an improved vibrator wafer level package structure according to the present invention.

The improved vibrator wafer level package structure according to the present invention includes a vibrator unit 20, an upper cover 10, a susceptor 40, a package ring 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 respectively have an upper surface electrode 21 and a lower surface electrode 22 (see FIG. 2), thereby exciting The vibrator unit 20 is 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 outer edge of the base 40 is provided with a package ring 30. The package ring 30 can be made of copper, tin, gold, silver, indium, and an alloy of the above metals, an organic polymer. If the encapsulation ring 30 is made of a metal material and the upper cover 10 and the susceptor 40 are electrically conductive, a layer of insulation must be provided between the two to prevent the upper cover 10 and the susceptor 40 from being electrically connected. The package ring 30 is provided for providing the upper cover 10, and the upper cover 10 has a recess 11 for accommodating the vibrator unit 20. Therefore, the upper cover 10 and the base 40 are transmitted through the sealing ring 30, and the vibrator unit 20 can be hermetically sealed, and the internal environment can be vacuum or filled with nitrogen; the upper cover 10 can be made of bismuth, glass, quartz, ceramic, or metal. Materials, etc., the material of the susceptor 40 may also be non-conductive materials such as enamel, glass, quartz, ceramics, etc. Further, if the two materials (the upper cover 10 and the susceptor 40) are selected from the same material, the problem of thermal stress can be further prevented. .

The outer edge of the encapsulation ring 30 is aligned with the upper cover 10 and the base 40 to form a complete groove-free plane to reduce the accumulation of contaminants; and the inner edge of the encapsulation ring 30 is cut from the edge of the recess 11 of the upper cover 10. In alignment, the area of the package ring 30 can be increased to improve the joint strength and sealing effect.

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.

The manufacturing process of the package ring 30, as shown in FIGS. 3A and 3B, when the package ring 30 is formed on the upper cover 10 via patterning, the package ring 30 can be used as a mask and etched to form the groove 11 at the same time. And further encapsulation using the encapsulation ring 30 (see Figure 3B). In order to further simplify the production process and reduce production costs.

Wherein, when the package ring 30 is an alloy of copper, tin, gold, silver, indium or the above metal, it can be formed by metal fusion bonding or thermal-compression bonding; when the package ring 30 is In the case of an organic polymer, the encapsulation can be achieved by a bonding technique, and when the encapsulating ring 30 is made of an oxidizing material such as cerium oxide, the encapsulation can be achieved by anodic bonding.

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. 4 , which is a schematic diagram of a second embodiment of a modified vibrator wafer level package structure 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 FIG. 5 ). .

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. 6A, 6B, respectively, corresponding to the first embodiment and the second embodiment; in this case, the inner edge of the package ring 30 is aligned with the edge of the recess 42 of the base 40, too, It can also serve as a mask for forming the recess 42 of the susceptor 40.

Please refer to FIGS. 7 and 8 for a schematic view of a third embodiment of the improved vibrator wafer level package structure of the present invention. In the above embodiment, the conductive vias 50 are designed to extend under the conductive bumps 23 of the vibrator unit 20; in this embodiment, the conductive vias 50 are designed to penetrate vertically below the package ring 30 due to the conductive vias. 50 is formed by the via via technology, and the via is one of the factors affecting the internal airtightness. Therefore, in this embodiment, the conductive via 50 is opened in the package ring 30 by way of routing. Below, when the packaging process is performed, the factors affecting the hermeticity of the package are left, and only the bonding of the package ring 30 is left, and the internal package gas is not exchanged with the outside through the via hole. Therefore, the airtightness of the overall package structure will be more easily controlled. Of course, the change of the groove 11 and the relative position of the upper surface electrode 21 and the lower surface electrode 22 can also be changed as shown in the above embodiment (not shown).

The improved vibrator wafer level package structure disclosed in the present invention electrically connects the vibrator unit to the bottom base metal pad by vertically penetrating through the conductive through hole formed in the base, thereby jumping off The use of ceramic pedestal encapsulation (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, and reduce the length of the connection line, thereby Reduce 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 outer edge of the encapsulation ring is aligned with the upper cover and the base to form a complete groove-free plane to reduce the accumulation of contaminants; the inner edge of the encapsulation ring is aligned with the edge of the groove of the upper cover to increase the encapsulation ring. The area increases the joint strength and sealing effect.

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

21‧‧‧Upper surface electrode

22‧‧‧ lower surface electrode

23‧‧‧Electrical bumps

30‧‧‧Package ring

40‧‧‧Base

41‧‧‧Base metal pad

42‧‧‧ Groove

50‧‧‧ Conductive through hole

1 is a schematic view of a first embodiment of a modified vibrator wafer level package structure of the present invention.

2 is a schematic view of the upper and lower electrodes of the vibrator unit in the first embodiment of the improved vibrator wafer level package structure of the present invention.

3A and 3B are schematic views showing the manufacturing process of the package ring of the improved vibrator wafer level package structure according to the present invention.

4 is a schematic view showing a second embodiment of the improved vibrator wafer level package structure of the present invention.

FIG. 5 is a schematic view showing the upper and lower electrodes of the vibrator unit in the second embodiment of the improved vibrator wafer level package structure of the present invention.

FIG. 6A is a schematic view showing a variation of the groove in the first embodiment of the improved vibrator wafer level package structure of the present invention.

FIG. 6B is a schematic view showing a variation of the groove in the second embodiment of the improved vibrator wafer level package structure of the present invention.

Figure 7 is a schematic view showing a third embodiment of the improved vibrator wafer level package structure of the present invention.

FIG. 8 is a schematic diagram of the upper and lower electrodes and the package ring of the vibrator unit in the third embodiment of the improved vibrator wafer level package structure of 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

40. . . Pedestal

41. . . Base metal pad

50. . . Conductive through hole

Claims (10)

An improved vibrator wafer level package structure, comprising: a vibrator unit; a base for the vibrator unit; a package ring disposed on the base and aligned with the outer edge of the base; An upper cover is disposed on the package ring and disposed on the vibrator unit, and encapsulates the vibrator unit and is aligned with an outer edge of the package ring; and at least one conductive via is vertically disposed on the base and is The vibrator unit is electrically connected to provide signal input/output. The improved vibrator wafer level package structure 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 improved vibrator wafer level package structure according to claim 1, wherein the upper cover is composed of one of bismuth, glass, quartz, ceramic and metal materials, and the package ring is made of copper, tin, gold, Silver, indium and one of the above materials of the alloy, the organic polymer and the oxide, the pedestal is composed of one of bismuth, glass, quartz and ceramic materials, and the conductive via is selected from the group consisting of copper, silver and gold. A combination of tungsten, and alloys thereof, polycrystalline germanium, and conductive polymers. The improved vibrator wafer level package structure of 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 respectively comprise a conductive bump Electrically connected to the conductive via, and the conductive bump is composed of one of a mixed conductive paste of a silver powder particle and a resin, and a metal bump, which is made of gold, copper, tin, silver, indium, and One of its alloys. The improved vibrator 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 improved vibrator wafer level package structure of claim 1, wherein the upper cover has a recess for receiving the vibrator unit, and an inner edge of the encapsulation ring is aligned with the recess. The improved vibrator wafer level package structure of claim 1, wherein the base has a recess for receiving the vibrator unit, and an inner edge of the encapsulation ring is aligned with the recess . The improved vibrator wafer level package structure of claim 1, wherein the conductive via is disposed under the package ring. The improved vibrator wafer level package structure of claim 1, wherein the conductive via is formed by a via via technology. The improved vibrator wafer level package structure of claim 1, wherein the bottom of the base further comprises a base metal pad for electrically connecting to the conductive via.