Ultrasonically resistant air bridge and method of making same

Abstract

Provided are a method for manufacturing an ultrasonic-resistant air bridge, comprising: forming an air bridge on a deposition surface; wherein the air bridge comprises a bridge pier part in contact with the deposition surface, and a bridge body part spanning on the bridge pier part; and forming a reinforcing part on the bridge pier part and the deposition surface. Also provided is an ultrasonic-resistant air bridge. The ultrasonic-resistant air bridge and the method for manufacturing the same have the advantages that the air bridge is more firm due to the deposition of the reinforcing material on the bridge pier part and the deposition surface, and the connection between the bridge pier part and the deposition surface is not easily broken by impact in an ultrasonic environment.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, specifically, it relates to an ultrasonic-resistant air bridge and its manufacturing method. Background Technology

[0002] An air bridge is a cross-connection technology that uses a three-dimensional bridge structure to bridge planar circuits. It can solve unwanted parasitic effects in circuits. Because the medium between the bridge surface and the circuit is air or vacuum, it is called an air bridge. Furthermore, air bridge structures are particularly common in the field of superconducting quantum chips.

[0003] The conventional method for preparing air bridges is roughly as follows: After coating and developing the photoresist on a material plane, the photoresist is heated and reflowed to form an arch shape as a bridge support. Then, a layer of conductive material is deposited on the photoresist, and another layer of photoresist is coated on the deposited layer. The photoresist is patterned to protect the bridge surface. The deposited material outside the bridge surface is then removed by etching. Finally, all the photoresist is removed to obtain the air bridge.

[0004] However, when using air bridges fabricated using the conventional methods described above, malfunctions often occur in devices. Microscopic observation reveals device damage due to air bridge collapse and breakage. Breakage is particularly common at the corner where the air bridge connects to the substrate, for two reasons: first, the air bridge has an arched structure, with the primary stress point being the corner where the bridge surface connects to the substrate; second, during the thin film deposition process on the air bridge "bridge surface," due to the arched structure, less material is deposited at the corner where the bridge surface connects to the substrate, making this corner weaker. In such cases, when the device fabrication involves ultrasonic processes, such as ultrasonic resist removal or cleaning, the instantaneous high-pressure impact of ultrasonic bubbles will almost always cause the air bridge to break, leading to device failure. This significantly limits the application range of air bridges. Summary of the Invention

[0005] To address the technical problems existing in the prior art, the present invention provides an ultrasonic-resistant air bridge capable of reinforcing weak points of an air bridge and a method for manufacturing the same.

[0006] A method for manufacturing an ultrasonic-resistant air bridge according to a first aspect of an embodiment of the present invention includes: forming an air bridge on a deposition surface; wherein the air bridge includes: a pier portion in contact with the deposition surface, and a bridge body portion spanning the pier portion; and forming a reinforcing portion on the pier portion and the deposition surface.

[0007] In one example of the manufacturing method provided in the first aspect above, the manufacturing method further includes: forming a reinforcing part at the connection between the pier part and the bridge body part.

[0008] In one example of the manufacturing method provided in the first aspect above, the method of forming an air bridge on a deposition surface includes: forming a bridge support structure conforming to the shape of the air bridge on the deposition surface; forming the air bridge on the bridge support structure; and removing the bridge support structure.

[0009] In one example of the manufacturing method provided in the first aspect above, the method of forming a bridging structure conforming to the shape of the air bridge on the deposition surface includes: depositing bridging material on the deposition surface; patterning the bridging material; and heating and reflowing the patterned bridging material to form the bridging structure including a bridging portion and a planar portion spaced apart from the bridging portion.

[0010] In one example of the fabrication method provided in the first aspect above, the method of forming the air bridge on the bridging structure includes: depositing a bridging material on the bridging structure and the deposition surface; spin-coating a photoresist material onto the bridging material; patterning the photoresist material, retaining only the photoresist material located on the bridging portion and in the gap between the bridging portion and the planar portion; removing the exposed bridging material; and removing the remaining photoresist material, the bridging portion, and the planar portion to form the air bridge.

[0011] In one example of the fabrication method provided in the first aspect above, the method of forming a reinforcing portion on the pier portion and the deposition surface includes: spin-coating a photoresist material on the bridge body portion and the deposition surface; wherein the photoresist material deposited on the deposition surface has a gap with the pier portion; depositing a reinforcing material on the pier portion, the deposition surface exposed by the gap, and the photoresist material; and removing the photoresist material and the reinforcing material thereon to form the reinforcing portion on the pier portion and the deposition surface.

[0012] In one example of the fabrication method provided in the first aspect above, the method of spin-coating photoresist material on the bridge body and the deposition surface includes: sequentially forming a first photoresist material and a second photoresist material stacked on the first photoresist material on the bridge support and the deposition surface; and patterning the first photoresist material and the second photoresist material to remove the first photoresist material and the second photoresist material located on the bridge pier and in the interval.

[0013] The ultrasonic-resistant air bridge provided according to a second aspect of an embodiment of the present invention is formed by the above-described manufacturing method.

[0014] A third aspect of an embodiment of the present invention provides an ultrasonic-resistant air bridge comprising: a pier portion on a deposition surface; a bridge body portion spanning the pier portion; and a reinforcement portion on the pier portion and extending to the deposition surface.

[0015] In one example of the ultrasonic-resistant air bridge provided in the third aspect above, the reinforcement extends to the joint between the pier and the bridge body.

[0016] Beneficial effects: The ultrasonic-resistant air bridge and its manufacturing method of the present invention are made more robust by depositing reinforcing materials on the bridge pier and the deposition surface, making the connection between the bridge pier and the deposition surface less prone to impact and breakage in an ultrasonic environment. Attached Figure Description

[0017] The above and other aspects, features, and advantages of embodiments of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0018] Figure 1 This is a schematic diagram of the structure of an ultrasonic-resistant air bridge according to an embodiment of the present invention;

[0019] Figure 2 This is a flowchart of a method for manufacturing an ultrasonic-resistant air bridge according to an embodiment of the present invention;

[0020] Figures 3A to 3M This is a detailed process diagram of an ultrasonic-resistant air bridge according to an embodiment of the present invention. Detailed Implementation

[0021] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can be implemented in many different forms, and should not be construed as limited to the specific embodiments set forth herein. Rather, these embodiments are provided to explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the various embodiments of the invention and various modifications suitable for particular intended applications.

[0022] As used herein, the term "comprising" and its variations are open terms meaning "including but not limited to". The terms "based on", "according to", etc., mean "at least partially based on" or "at least partially according to". The terms "one embodiment" and "an embodiment" mean "at least one embodiment". The term "another embodiment" means "at least one other embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other definitions, whether explicit or implicit, may be included below. Unless explicitly indicated by the context, the definition of a term remains consistent throughout the specification.

[0023] Figure 1This is a schematic diagram of the structure of an ultrasonic-resistant air bridge according to an embodiment of the present invention.

[0024] Reference Figure 1 According to an embodiment of the present invention, the ultrasonic-resistant air bridge 10 includes: a pier portion 11 on the deposition surface; a bridge body portion 12 spanning the pier portion 11; and a reinforcement portion 13 on the pier portion 11 and extending to the deposition surface.

[0025] Here, the deposition surface can be a surface of the substrate 20, or of course, the surface of other objects. The present invention does not make any specific limitation.

[0026] Furthermore, in another embodiment, the reinforcing part 13 extends to the junction (or corner) between the pier part 11 and the bridge body part 12.

[0027] Figure 2 This is a flowchart illustrating the fabrication process of an ultrasonic-resistant air bridge according to an embodiment of the present invention.

[0028] Refer to together Figure 1 and Figure 2 In step S210, an air bridge 10 is formed on the deposition surface; wherein the air bridge 10 includes: a pier portion 11 on the deposition surface; and a bridge body portion 12 spanning the pier portion 11.

[0029] In step S220, a reinforcement portion 13 is formed on the pier portion 11 and the deposition surface.

[0030] The following will refer to Figures 3A to 3M The detailed manufacturing process of the ultrasonic-resistant air bridge according to an embodiment of the present invention is described in detail, thereby further explaining... Figure 1 and Figure 2 .

[0031] Reference Figure 3A Step one: Provide a substrate 20. In this embodiment, the substrate 20 can be cleaned. As an example, the cleaning process can be: ultrasonically clean the substrate 20 with acetone and isopropanol for 5 minutes each, then ultrasonically clean the substrate 20 multiple times with deionized water, and finally dry the substrate 20 with nitrogen gas.

[0032] Reference Figure 3B Step two involves coating (or spin-coating) a layer of photoresist 100 onto the substrate 20. Here, photoresist 100 serves as the bridging material, and its thickness determines the height of the air bridge 10 to be formed. Therefore, a photoresist with high adhesion needs to be selected, ensuring a thickness greater than 3 μm. For example, photoresist 100 can be SPR220-3 photoresist.

[0033] Reference Figure 3CStep three involves patterning the photoresist 100 (i.e., exposure patterning, development, etching, etc.). The exposure process includes ultraviolet exposure or laser direct writing.

[0034] Reference Figure 3D Step four: The patterned photoresist 100 is heated and reflowed. Under the action of surface tension, the photoresist 100 forms an arch shape, resulting in a bridge structure composed of a bridge support portion 110 and a planar portion 120 spaced apart from the bridge support portion 110.

[0035] It should be noted that through steps one to four above, a bridging structure conforming to the shape of an air bridge is formed on the deposition surface (one surface of the substrate 20).

[0036] Reference Figure 3E Step five involves depositing bridging material 200 on the bridging structure and the deposition surface exposed by the interval. The bridging material can be a metallic material, such as aluminum or niobium. The bridging material can be deposited using methods such as electron beam evaporation or magnetron sputtering.

[0037] Reference Figure 3F Step six: Spin-coat photoresist 300 onto the bridge material 200. Here, the photoresist 300 needs to cover the bridge support 110, so the thickness of the photoresist 300 needs to be greater than the height of the bridge support 110. Therefore, the photoresist 300 should also be a photoresist with strong adhesion. For example, the photoresist 300 can be SPR220-3 photoresist.

[0038] Reference Figure 3G Step 7: Pattern the photoresist 300 (i.e., exposure patterning, development, etching, etc.), retaining only the photoresist 300 located on the bridge support portion 110 and the space between the bridge support portion 110 and the planar portion 120.

[0039] Reference Figure 3H Step 8: Remove the exposed bridge material 200.

[0040] It should be noted that through steps five to eight above, the air bridge 10 is formed on the bridge support structure.

[0041] Reference Figure 3I Step nine: Remove the remaining photoresist 300 and the bridge support structure.

[0042] Reference Figure 3J Step 10: A first layer of photoresist 400 and a second layer of photoresist 500 are sequentially spin-coated onto the surfaces of the air bridge 10 and the substrate 20. Since the first layer of photoresist 400 is spin-coated, and photoresist has fluidity, it can fill the space beneath the air bridge 10.

[0043] The thickness of the first layer of photoresist 400 needs to be greater than the height of the air bridge 10. For example, the first layer of photoresist 400 can be a LOR photoresist.

[0044] Reference Figure 3K Step eleven: pattern the first layer of photoresist 400 and the second layer of photoresist 500 (i.e., exposure patterning, development, etching, etc.) to remove the first layer of photoresist 400 and the second layer of photoresist 500 located on the pier portion 11 (which may also include the connection between it and the bridge body portion 12) and in the interval.

[0045] It should be noted that photoresist material is spin-coated onto the bridge body 12 and the deposition surface through steps ten and eleven; wherein the photoresist material deposited on the deposition surface has the aforementioned interval with the bridge pier 11.

[0046] Reference Figure 3L Step 12: Deposit reinforcing material 600 on the pier portion 11, the deposition surface (substrate 20 surface) exposed by the interval, and the second layer of photoresist 500.

[0047] Reference Figure 3M Step thirteen: Remove the remaining first layer of photoresist 400, second layer of photoresist 500 and the reinforcing material 600 thereon to form the reinforcing part 13 on the pier part 11 and the deposition surface.

[0048] Of course, if the joint between the pier portion 11 and the bridge body portion 12 is also exposed, then a reinforcing material is also formed at the joint between the pier portion 11 and the bridge body portion 12. That is, the reinforcing portion 13 extends from the joint between the pier portion 11 and the bridge body portion 12, covering the pier portion 11, and extends from the pier portion 11 to the deposition surface. Therefore, the air bridge manufactured by the method according to the embodiment of the present invention is more robust because a reinforcing material is deposited on the pier portion 11 and the deposition surface, and the joint between the pier portion 11 and the deposition surface is less likely to be impacted and broken in an ultrasonic environment.

[0049] The terms “exemplary,” “example,” etc., used throughout this specification mean “serving as an example, instance, or illustration” and do not imply “preferred” or “advantageous” than other embodiments. Detailed descriptions are included for the purpose of providing an understanding of the described techniques. However, these techniques can be practiced without these detailed descriptions. In some instances, well-known structures and apparatuses are shown in block diagram form to avoid obscuring the concepts of the described embodiments.

[0050] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

[0051] The foregoing description of this specification is provided to enable any person skilled in the art to implement or use the content of this specification. Various modifications to the content of this specification will be apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the scope of protection of this specification. Therefore, this specification is not limited to the examples and designs described herein, but is consistent with the widest scope of the principles and novel features disclosed herein.

Claims

1. A method for fabricating an ultrasonic-resistant air bridge, characterized in that, The manufacturing method includes: An air bridge is formed on the deposition surface; wherein the air bridge includes: a pier portion in contact with the deposition surface, and a bridge body portion spanning the pier portion; Reinforcing sections are formed on the bridge pier and the deposition surface. The method for forming the reinforcement portion on the bridge pier and the deposition surface includes: A first photoresist material and a second photoresist material stacked on the first photoresist material are sequentially formed on the bridge body and the deposition surface; The first photoresist material and the second photoresist material are patterned to remove the first photoresist material and the second photoresist material located on the pier portion and in the gap, wherein the gap is located between the first photoresist material retained on the deposition surface and the pier portion; A reinforcing material is deposited on the pier portion, the deposition surface exposed by the interval, and the second photoresist material; The remaining first photoresist material, second photoresist material, and reinforcing material thereon are removed to form the reinforcing portion on the pier portion and the deposition surface.

2. The manufacturing method according to claim 1, characterized in that, The manufacturing method further includes: A reinforcement section is formed at the connection between the pier section and the bridge body section.

3. The manufacturing method according to claim 1 or 2, characterized in that, The method for creating an air bridge on the deposition surface includes: A bridge support structure conforming to the shape of the air bridge is formed on the deposition surface; The air bridge is formed on the bridge support structure; Remove the bridge support structure.

4. The manufacturing method according to claim 3, characterized in that, The method for fabricating a bridging structure conforming to the shape of the air bridge on the deposition surface includes: A bridging material is deposited on the deposition surface; The bridge support material is patterned. The patterned bridge material is heated and reflowed to form the bridge structure, which includes a bridge support portion and a planar portion spaced apart from the bridge support portion.

5. The manufacturing method according to claim 4, characterized in that, The method of forming the air bridge on the bridge support structure includes: Deposit bridging material on the bridging structure and the deposition surface; A photoresist material is spin-coated onto the bridge material; The photoresist material is patterned, retaining only the photoresist material located on the bridge support portion and the space between the bridge support portion and the planar portion; Remove the exposed bridge material; The remaining photoresist material, the bridge support, and the planar portion are removed to form the air bridge.

6. An ultrasonic-resistant air bridge manufactured by the manufacturing method according to any one of claims 1 to 5.

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