A silicon-based etching high aspect ratio structure based on ultrasonic magnetic field coupling effect and its research method

Abstract

The present invention discloses a silicon-based etching high aspect ratio structure based on ultrasonic magnetic field coupling and a research method thereof. By arranging an ultrasonic transducer probe and an electromagnet, the magnetic force of the electromagnet can enhance the etching rate and improve the perpendicularity of the etched holes. The ultrasonic and magnetic field coupling is used for high aspect ratio etching of silicon-based materials, reducing surface damage and mechanical stress, effectively ensuring the etching accuracy and the quality of the sidewalls, forming a silicon microchannel with a reasonable high aspect ratio, ensuring the use effect, and being beneficial to the popularization and application of the above-mentioned silicon-based etching high aspect ratio structure based on ultrasonic magnetic field coupling in the field of micro-nano manufacturing technology.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro-nano manufacturing, and specifically relates to a silicon-based etching high aspect ratio structure based on the coupling effect of ultrasonic wave and magnetic field and a research method thereof. Background Art

[0002] Magnetic conduction metal-assisted chemical etching is a wet etching technology for etching high aspect ratio (HAR) structures on a silicon substrate. Essentially, it is an oxidation-reduction reaction, and a noble metal is deposited on the silicon surface as a catalyst. When the silicon substrate deposited with a metal catalyst is immersed in an aqueous solution of hydrofluoric acid-hydrogen peroxide, an oxidation-reduction reaction occurs, and the silicon volume under the catalyst is dissolved. The catalyst will further move into the etched cavity to assist continuous etching and form a HAR structure. Electron holes (h+) are generated on the surface of the metal catalyst during the oxidation-reduction reaction, and the transport of electron holes may seriously affect the three-dimensional distribution of metal-assisted chemical etching (MaCE). We call the movement process of h+ the charge transport process. In magnetic conduction chemical etching, a magnetic three-layer metal catalyst (Au / Fe / Au) is used instead of a single noble metal layer. Then, under the action of an external magnetic field, the sample is electrochemically etched along the required etching direction, improving the etching rate and the etching perpendicularity. In order to enhance the kinetics and control the direction, a magnetic iron layer is deposited for magnetic-guided silicon etching.

[0003] However, the current magnetic field-assisted metal chemical etching method lacks the research on the coupling interaction between ultrasonic wave and magnetic field. During the structure forming process, the surface structure still has damage, resulting in uneven surface quality of the formed structure, and it is impossible to achieve silicon microchannels with high-precision, high-quality sidewalls and high aspect ratios. Summary of the Invention

[0004] In order to overcome the defects in the above-mentioned prior art, the first object of the present invention is to provide a silicon-based etching high aspect ratio structure based on the coupling effect of ultrasonic wave and magnetic field. This structure is ingenious and can effectively ensure the etching precision and the quality of the sidewalls, forming a silicon microchannel with a reasonable high aspect ratio. The second object of the present invention is to provide a research method for a silicon-based etching high aspect ratio structure based on the coupling effect of ultrasonic wave and magnetic field. This research method can also effectively ensure the etching precision and the quality of the sidewalls, forming a silicon microchannel with a reasonable high aspect ratio, ensuring the use effect, and being beneficial to the popularization and application of the above-mentioned silicon-based etching high aspect ratio structure based on the coupling effect of ultrasonic wave and magnetic field in the technical field of micro-nano manufacturing.

[0005] The above-mentioned silicon-based etching high aspect ratio structure based on the coupling effect of ultrasonic wave and magnetic field and the research method for the silicon-based etching high aspect ratio structure based on the coupling effect of ultrasonic wave and magnetic field are technically interrelated and belong to the same inventive concept.

[0006] To achieve the first above-mentioned invention object, the present invention adopts the following technical solution: A silicon-based etching high aspect ratio structure based on ultrasonic magnetic field coupling, comprising an ultrasonic transducer probe, a catalyst layer, a magnetic iron layer, a photoresist template, a silicon substrate and an electromagnet. The ultrasonic transducer probe is arranged above the silicon substrate. The catalyst layer is deposited above and below the magnetic iron layer. The photoresist template with a certain thickness is used as a mask plate and is covered on the surface of the silicon substrate. The electromagnet is arranged below the silicon substrate and is not in contact with the silicon substrate.

[0007] As a preferred solution of the present invention, the central axis of the ultrasonic transducer probe and the central axis of the silicon substrate are on the same straight line.

[0008] As a preferred solution of the present invention, the electromagnet is arranged directly below the silicon substrate.

[0009] As a preferred solution of the present invention, the photoresist template is made of a corrosion-resistant material.

[0010] To achieve the second above-mentioned invention object, the present invention adopts the following technical solution: A research method for a silicon-based etching high aspect ratio structure based on electromagnetic field action, comprising the following steps: S1, using the photoresist template as a mask to obtain the structure of cylindrical micropores of the catalyst layer etching the silicon substrate; S2, a controllable electromagnet is placed below the silicon substrate; S3, the ultrasonic wave of the ultrasonic transducer probe and the magnetic field of the electromagnet are coupled with each other to form a high aspect ratio etching of the silicon substrate.

[0011] As a preferred solution of the present invention, in S1, a photoresist template with high corrosion resistance to the catalyst layer is used as a mask. The catalyst layer is deposited above and below the magnetic iron layer. Before etching, an annealing treatment is first carried out.

[0012] As a preferred solution of the present invention, in S1, a cylindrical hole structure is etched on the surface of the silicon substrate.

[0013] As a preferred solution of the present invention, in S3, a micro ultrasonic machine is placed above the hole of the silicon substrate to be etched for processing tests. Using a solid cylindrical tungsten carbide rod as a tool, the ultrasonic transducer probe is aligned with the cylindrical hole of the silicon substrate, and the ultrasonic wave is used to process the silicon substrate by high-frequency etching process.

[0014] Compared with the prior art, a silicon-based etching high aspect ratio structure based on ultrasonic magnetic field coupling and its research method in the present invention have the following beneficial effects: A silicon-based etching high aspect ratio structure based on ultrasonic magnetic field coupling and its research method in the present invention, by setting an ultrasonic transducer probe and an electromagnet, the magnetic force of the electromagnet can enhance the etching rate and improve the verticality of the etched holes. The ultrasonic and magnetic field coupling acts on the high aspect ratio etching of silicon-based, reducing surface damage and mechanical stress, and can effectively ensure the etching accuracy and the quality of the sidewalls, forming a reasonable high aspect ratio silicon microchannel, ensuring the use effect, and being beneficial to the popularization and application of the above-mentioned silicon-based etching high aspect ratio structure based on ultrasonic magnetic field coupling in the field of micro-nano manufacturing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram of a silicon-based photonic crystal with an anti-corrosion photoresist mask layer on its surface in the embodiment;

[0016] Figure 2 is a schematic diagram of the formation of a high aspect ratio etched silicon-based under ultrasonic-magnetic field coupling in the embodiment;

[0017] Figure 3 is the schematic diagram of the principle of silicon-based etching under ultrasonic-magnetic field coupling in the embodiment.

[0018] Reference numerals: 1, ultrasonic transducer probe; 2, catalyst; 3, photoresist; 4, silicon-based; 5, electromagnet; 6, magnetic iron layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0020] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0021] The present invention will be further described below with reference to the drawings and specific embodiments, but it is not limited to the present invention.

[0022] Such as Figures 1 to 3As shown in the figure, a silicon-based etching high aspect ratio structure based on ultrasonic magnetic field coupling includes an ultrasonic transducer probe 1, a catalyst layer 2, a magnetic iron layer 6, a photoresist template 3, a silicon substrate 4, and an electromagnet 5. The ultrasonic transducer probe 1 is arranged above the silicon substrate 4. The catalyst layer 2 is deposited above and below the magnetic iron layer 6. The photoresist template 3 with a certain thickness is used as a mask and is coated on the surface of the silicon substrate 4. The electromagnet 5 is arranged below the silicon substrate 4 and is not in contact with the silicon substrate 4.

[0023] To ensure the etching effect of the silicon substrate, the central axis of the ultrasonic transducer probe 1 and the central axis of the silicon substrate 4 are arranged on the same straight line. The electromagnet 5 is arranged directly below the silicon substrate 4. The magnetic force of the electromagnet 5 enhances the etching rate and improves the verticality of the etched holes.

[0024] The photoresist template 3 is made of a corrosion-resistant material.

[0025] A research method for a silicon-based etching high aspect ratio structure based on ultrasonic magnetic field coupling includes the following steps:

[0026] S1: Using the photoresist template 3 as a mask, a cylindrical microporous structure of the silicon substrate 4 etched by the catalyst layer 2 is obtained. Specifically, the photoresist template 3 is used as a mask, and a photoresist with high corrosion resistance to the catalyst layer 2 is used to protect the surface of the silicon substrate 4 that does not need to be etched during the etching process. The noble metal catalyst layer 2 is deposited above and below the magnetic iron layer 6 to protect the magnetic iron layer 6 from being corroded by the etching solution during the etching process. Before etching, an annealing treatment is first performed to increase the magnetism of Fe or to make the surface of Au more likely to react with the etching solution.

[0027] S2: A controllable electromagnet 5 is placed below the silicon substrate 4. The magnetic force of the electromagnet 5 enhances the etching rate and improves the verticality of the etched holes. Specifically, when etching a cylindrical hole structure on the surface of the silicon substrate 4, since there are a large number of free electrons in the N-type silicon wafer, during the etching process, silicon loses electrons and the electrons enter the solution. A large number of electrons gather around the metal particles, so the metal particles are charged. The noble metal catalyst contains Fe in the middle, so under the action of the magnetic field, it will move downward, that is, in the direction of the electromagnet 5. By adjusting the magnetic force of the electromagnet 5, the best magnetic force effect can be obtained.

[0028] S3. The ultrasonic wave of the ultrasonic transducer probe 1 and the magnetic field of the electromagnet 5 are coupled with each other to form a silicon-based structure 4 with a high aspect ratio, reducing surface damage and mechanical stress. Specifically, a micro ultrasonic machine is placed above the silicon-based hole to be etched for processing tests. Using a solid cylindrical tungsten carbide rod as a tool, the ultrasonic transducer probe 1 is aligned with the silicon-based cylindrical hole, and the silicon-based high-frequency etching process is carried out under the action of ultrasonic waves. The ultrasonic wave action increases the etching depth. More importantly, the ultrasonic wave can improve the damage of the side wall of the etched silicon-based material, reduce surface roughness, overcut, stray cutting and other adverse corresponding parameters to etch high-precision and high-quality silicon microchannels. The electromagnet acts on the metal catalyst, and the magnetic force of the electromagnet 5 enhances the etching rate and guides vertical etching. The coupling action of ultrasonic waves and the magnetic field can achieve a further high aspect ratio etching and improve the surface finish and shape accuracy of the side wall.

[0029] In this embodiment, a silicon-based etching high aspect ratio structure and its research method based on the coupling action of ultrasonic waves and magnetic fields are provided. By setting the ultrasonic transducer probe 1 and the electromagnet 5, the magnetic force of the electromagnet 5 can enhance the etching rate and improve the verticality of the etched hole. The coupling action of ultrasonic waves and the magnetic field etches the silicon-based material with a high aspect ratio, reducing surface damage and mechanical stress, effectively ensuring the etching accuracy and the quality of the side wall, forming a silicon microchannel with a reasonable high aspect ratio, ensuring the use effect, and being beneficial to the promotion and application of the silicon-based etching high aspect ratio structure based on the coupling action of ultrasonic waves and magnetic fields in the field of micro-nano manufacturing technology.

[0030] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0031] Although terms such as 1. ultrasonic transducer probe; 2. catalyst; 3. photoresist; 4. silicon-based; 5. electromagnet; 6. magnetic iron layer and other terms are used more frequently in the figures in this article, the possibility of using other terms is not excluded. These terms are only used to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A research method for silicon-based etching of high aspect ratio structures based on ultrasonic magnetic field coupling, characterized in that: Silicon-based etching of high aspect ratio structures based on ultrasonic magnetic field coupling, including an ultrasonic transducer probe (1), a catalyst layer (2), a magnetic iron layer (6), a photoresist template (3), a silicon substrate (4), and an electromagnet (5). The ultrasonic transducer probe (1) is arranged above the silicon substrate (4). The catalyst layer (2) is deposited above and below the magnetic iron layer (6). The photoresist template (3) with a certain thickness is used as a mask and is coated on the surface of the silicon substrate (4). The electromagnet (5) is located below the silicon substrate (4) and is arranged without contacting the silicon substrate (4). The central axis of the ultrasonic transducer probe (1) and the central axis of the silicon substrate (4) are on the same straight line. The electromagnet (5) is arranged directly below the silicon substrate (4). The photoresist template (3) is made of a corrosion-resistant material. The research method includes the following steps: S1, using the photoresist template (3) as a mask to obtain the structure of cylindrical micropores in the silicon substrate (4) etched by the catalyst layer (2); S2, placing a controllable electromagnet (5) below the silicon substrate (4); S3, the ultrasonic waves of the ultrasonic transducer probe (1) and the magnetic field of the electromagnet (5) interact and couple to form high aspect ratio etching of the silicon substrate (4). In S1, a photoresist template (3) with high corrosion resistance to the catalyst layer (2) is used as a mask. The catalyst layer (2) is deposited above and below the magnetic iron layer (6). Before etching, an annealing treatment is carried out first. In S1, cylindrical hole structures are etched on the surface of the silicon substrate (4). In S3, a micro ultrasonic machine is placed above the silicon-based holes to be etched for processing tests. Using a solid cylindrical tungsten carbide rod as a tool, the ultrasonic transducer probe (1) is aligned with the silicon-based cylindrical holes, and ultrasonic high-frequency etching technology is used for processing.

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