Surface acoustic wave filter chip containing copper film and filter

Abstract

The invention discloses a copper film-containing surface acoustic wave filter chip and a filter. The copper film-containing surface acoustic wave filter chip comprises a substrate layer and an electrode layer arranged on the upper surface of the substrate layer, the electrode layer comprises a copper film layer, two electrode areas are arranged on the electrode layer, the area, except the electrode areas, of the electrode layer is a non-electrode area, a channel is etched in the non-electrode area on the electrode layer, a first protection layer is arranged in the non-electrode area, a second protection layer is arranged in the electrode area, and the first protection layer and the second protection layer are arranged on the electrode layer. Therefore, the electrode layer contains the copper film layer, the electrode layer has lower resistivity and stray capacitance, the power consumption and delay of the surface acoustic wave filter chip can be reduced, signal crosstalk is reduced, the non-electrode area is covered with the first protection layer, the copper film layer can be prevented from being oxidized and stripped, and the surface acoustic wave filter chip can be manufactured. Therefore, the stability of the surface acoustic wave filter chip is integrally improved.

Description

Technical Field

[0001] The invention belongs to the technical field of filter chips, and in particular relates to a copper-film surface acoustic wave filter chip and a filter. Background Art

[0002] Aluminum is a commonly used electrode material for surface acoustic wave filters. However, the relative bandwidth that surface acoustic wave filters prepared with aluminum electrodes can achieve is relatively small, and it is gradually difficult to meet the requirements of the communication field for large bandwidth. Surface acoustic wave filters prepared with copper film as electrodes can achieve a larger relative bandwidth, and they have lower resistivity and parasitic capacitance, which helps to reduce power consumption and delay of the circuit, reduce signal crosstalk, and at the same time, copper materials are more resistant to electromigration effects. With the increase in the operating frequency and power of surface acoustic wave filters, copper materials have become a better choice. At present, in order to prevent the oxidation of copper films, there is a structure in which copper films are plated inside the etched silicon oxide channel, and the surface is protected by aluminum films. However, the preparation of this structure requires high overlay accuracy, cumbersome operation, complex etching process, and poor adhesion of aluminum films on the surface of copper films, which is prone to film shedding. Summary of the invention

[0003] In order to solve the above technical problems, one of the objectives of the present invention is to provide a copper-containing membrane surface acoustic wave filter chip with simple structure, good performance and good stability between membrane layers.

[0004] In order to achieve the above-mentioned purpose, the technical solution of the present invention is as follows: a copper film surface acoustic wave filter chip, comprising a substrate layer and an electrode layer arranged on the upper surface of the substrate layer; the electrode layer contains a copper film layer, and the electrode layer has two electrode areas, the area of ​​the electrode layer other than the electrode area is a non-electrode area, a groove is etched on the electrode layer in the non-electrode area, the non-electrode area is provided with a first protective layer, and the electrode area is provided with a second protective layer.

[0005] The beneficial effect of the above technical solution is that the electrode layer contains a copper film layer, which makes the electrode layer have lower resistivity and parasitic capacitance, which helps to reduce the power consumption and delay of the surface acoustic wave filter chip and reduce signal crosstalk. The first protective layer is used to cover the non-electrode area, which can prevent the copper film layer from oxidizing and peeling off, thereby improving the overall stability of the surface acoustic wave filter chip.

[0006] In the above technical solution, the electrode layer includes a first titanium film layer and a second titanium film layer sequentially arranged in the up and down direction, and the copper film layer is sandwiched between the first titanium film layer and the second titanium film layer.

[0007] The beneficial effect of the above technical solution is that the copper film layer is sandwiched between the first titanium film layer and the second titanium film layer, forming a titanium-copper-titanium sandwich structure, so that the copper film layer can be wrapped and protected by the two titanium film layers, thereby further preventing the copper film layer from oxidizing and peeling off.

[0008] The channel in the above technical solution runs through the first titanium film layer, the copper film layer and the second titanium film layer.

[0009] The beneficial effects of the above technical solution are: its structure is simple and the overlay precision is high.

[0010] In the above technical solution, the first protective layer is a SiO2 film layer.

[0011] The beneficial effect of the above technical solution is that it can provide better isolation protection for the non-electrode area to prevent oxidation of the copper film layer.

[0012] In the above technical solution, the thickness of the first protective layer is 20-40nm.

[0013] The beneficial effect of the above technical solution is that its thickness is moderate.

[0014] In the above technical solution, the second protective layer includes an aluminum film layer and a third titanium film layer arranged in sequence from top to bottom.

[0015] The beneficial effect of the above technical solution is that the second protective layer composed of aluminum and titanium protects the electrode area.

[0016] In the above technical solution, the thickness of the aluminum film layer is 1000-1500nm, and the thickness of the third titanium film layer is 3-10nm.

[0017] The beneficial effect of the above technical solution is that the thickness of the second protective layer is sufficient to meet the needs of subsequent silicon aluminum wire pressure welding operations.

[0018] In the above technical solution, the first protective layer fully covers the non-electrode area.

[0019] The beneficial effect of the above technical solution is that it has a good protective effect.

[0020] The thickness of the electrode layer in the above technical solution is 10-1000nm.

[0021] The beneficial effects of the above technical solution are: its structure is simple and its thickness is moderate, and the thickness of the first titanium film layer, the copper film layer and the second titanium film layer are selected according to needs.

[0022] A second object of the present invention is to provide a filter with simple structure and good performance.

[0023] In order to achieve the above object, another technical solution of the present invention is as follows: a filter comprises the copper-containing film surface acoustic wave filter chip as described above.

[0024] The beneficial effects of the above technical solution are: good performance and excellent stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of the copper-film surface acoustic wave filter chip described in an embodiment of the present invention.

[0026] In the figure: 1, substrate layer; 2, electrode layer; 21, copper film layer; 22, first titanium film layer; 23, second titanium film layer; 3, electrode area; 4, non-electrode area; 41, channel; 5, first protective layer; 6, second protective layer; 61, aluminum film layer; 62, third titanium film layer. DETAILED DESCRIPTION

[0027] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention. The present invention is described in more detail by way of example with reference to the accompanying drawings in the following paragraphs. According to the following description and claims, the advantages and features of the present invention will be more clearly described. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.

[0028] Example 1

[0029] like Figure 1 As shown, the present embodiment provides a copper film surface acoustic wave filter chip, comprising a substrate layer 1 and an electrode layer 2 arranged on the upper surface of the substrate layer 1; the electrode layer 2 contains a copper film layer 21, and the electrode layer 2 has two electrode areas 3, the area of ​​the electrode layer 2 other than the electrode area 3 is a non-electrode area 4, a groove 41 is etched on the electrode layer 2 in the non-electrode area 4, the non-electrode area 4 is provided with a first protective layer 5, and the electrode area 3 is provided with a second protective layer 6, so that the electrode layer contains a copper film layer, so that the electrode layer has lower resistivity and parasitic capacitance, which helps to reduce the power consumption and delay of the surface acoustic wave filter chip and reduce signal crosstalk, and the non-electrode area is covered with the first protective layer, which can prevent the copper film layer from oxidizing and peeling off, thereby improving the overall stability of the surface acoustic wave filter chip.

[0030] In the above technical solution, the electrode layer 2 includes a first titanium film layer 22 and a second titanium film layer 23 arranged in sequence along the up and down directions, and the copper film layer 21 is sandwiched between the first titanium film layer 22 and the second titanium film layer 23, so that the copper film layer is sandwiched between the first titanium film layer and the second titanium film layer, that is, a titanium-copper-titanium sandwich structure is formed, so that the copper film layer can be wrapped and protected by two layers of titanium film layers, thereby further preventing the copper film layer from oxidizing and peeling off.

[0031] In the above technical solution, the channel 41 penetrates the first titanium film layer 22, the copper film layer 21 and the second titanium film layer 23, and has a simple structure and high overlay accuracy.

[0032] In the above technical scheme, the first protective layer 5 is a SiO2 film layer, and the thickness of the first protective layer 5 is 20-40nm (specifically, it can be any value among 20nm, 21nm, 22nm, 23nm, 24nm, 25nm, 26nm, 27nm, 28nm, 29nm, 30nm, 31nm, 32nm, 33nm, 34nm, 35nm, 36nm, 37nm, 38nm, 39nm and 40nm, or the corresponding range between any two values), and the first protective layer 5 fully covers the non-electrode area 4.

[0033] In the above technical solution, the second protective layer 6 includes an aluminum film layer 61 and a third titanium film layer 62 arranged in sequence from top to bottom, the thickness of the aluminum film layer 61 is 1000-1500nm (specifically, it can be any value among 1000nm, 1050nm, 1100nm, 1150nm, 1200nm, 1250nm, 1300nm, 1350nm, 1400nm, 1450nm and 1500nm, or a range corresponding to any two values), and the thickness of the third titanium film layer 62 is 3-10nm (specifically, it can be any value among 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm and 10nm, or a range corresponding to any two values).

[0034] The thickness of the electrode layer 2 in the above technical solution is 10-1000nm (specifically, it can be any value among 10nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm and 1000nm, or a range corresponding to any two values). Specifically, the thickness of the first titanium film layer and the second titanium film layer can be 1-10nm (specifically, it can be any value among 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm and 10nm, or a range corresponding to any two values). The thickness of the copper film layer can be determined as needed under the premise of satisfying the above conditions (on the premise that the thicknesses of the electrode layer, the first titanium film layer and the second titanium film layer meet the requirements).

[0035] In this embodiment, the electrode layer adopts a titanium-copper-titanium sandwich structure. At this time, the copper film layer is wrapped by two titanium film layers, so that the copper film layer is not easily oxidized and corroded during use. The non-electrode area of ​​the electrode layer is fully covered with a first protective layer, which can further protect the copper film layer from oxidation. In addition, the electrode area is thickened with an aluminum-titanium structure, which facilitates subsequent silicon-aluminum wire welding operations.

[0036] The process flow of the copper film surface acoustic wave filter chip provided in this embodiment is simple, which reduces the requirements for overlay accuracy. It also improves the protection effect of the copper film layer, prevents the copper film layer from oxidizing during use or subsequent heating, maintains the stability of the device performance, and improves the reliability and service life of the product.

[0037] Example 2

[0038] This embodiment provides a filter, including the copper-containing film surface acoustic wave filter chip as described in Embodiment 1.

[0039] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the drawings and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A copper film surface acoustic wave filter chip, characterized in that: The invention comprises a substrate layer (1) and an electrode layer (2) arranged on the upper surface of the substrate layer (1); the electrode layer (2) contains a copper film layer (21), and the electrode layer (2) has two electrode areas (3); the area of ​​the electrode layer (2) other than the electrode areas (3) is a non-electrode area (4); a channel (41) is etched on the electrode layer (2) in the non-electrode area (4); the non-electrode area (4) is provided with a first protective layer (5), and the electrode area (3) is provided with a second protective layer (6).

2. The copper film surface acoustic wave filter chip according to claim 1, characterized in that: The electrode layer (2) comprises a first titanium film layer (22) and a second titanium film layer (23) which are arranged in sequence in the up-down direction, and the copper film layer (21) is sandwiched between the first titanium film layer (22) and the second titanium film layer (23).

3. The copper film surface acoustic wave filter chip according to claim 2, characterized in that: The channel (41) penetrates the first titanium film layer (22), the copper film layer (21) and the second titanium film layer (23).

4. The copper film surface acoustic wave filter chip according to claim 1, characterized in that: The first protective layer (5) is a SiO2 film layer.

5. The copper film surface acoustic wave filter chip according to claim 4, characterized in that: The thickness of the first protective layer (5) is 20-40 nm.

6. The copper film surface acoustic wave filter chip according to claim 1, characterized in that: The second protective layer (6) comprises an aluminum film layer (61) and a third titanium film layer (62) which are arranged in sequence from top to bottom.

7. The copper film surface acoustic wave filter chip according to claim 6, characterized in that: The thickness of the aluminum film layer (61) is 1000-1500 nm, and the thickness of the third titanium film layer (62) is 3-10 nm.

8. The copper film surface acoustic wave filter chip according to claim 1, characterized in that: The first protective layer (5) fully covers the non-electrode area (4).

9. The copper film surface acoustic wave filter chip according to claim 1, characterized in that: The thickness of the electrode layer (2) is 10-1000 nm.

10. A filter, characterized in that: It comprises a copper-containing film surface acoustic wave filter chip as described in any one of claims 1 to 9.

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