A method of manufacturing a metal electrode having a grating-like structure and the electrode

Abstract

The application provides a kind of grating-like structure metal electrode manufacturing method and electrode, first particle beam is emitted with IBE ion beam etching equipment to first angle under the shelter of mask etching metal layer to obtain rough grating-like structure metal electrode, second particle beam is emitted with IBE ion beam etching equipment to second angle under the shelter of mask etching rough grating-like structure metal electrode to obtain final grating-like structure metal electrode. That is, first etching with small angle can be used to preliminarily open metal layer to obtain rough grating-like structure metal electrode, then large angle is used to modify the top of metal layer by using the shelter of mask, when the mask is gradually consumed, particle beam can be gradually etched to the bottom of metal layer. In this way, the side wall metal dirt generated by small angle etching can be effectively removed, and at the same time, the metal side wall with special angle can be formed due to the time difference between the top and bottom of metal layer, so that the final grating-like structure metal electrode with regular appearance and low roughness is obtained.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a method for manufacturing a grating-like metal electrode and the electrode itself. Background Technology

[0002] In the integrated circuit (IC) or microelectronics industry, thin films of noble metals such as silver and gold have shown great potential in forming metal electrodes due to their low resistivity and good electromigration resistance. However, due to the limited volatility of these noble metals, it is difficult to form grating-like metal electrodes with good morphology through reactive plasma etching. Similarly, wet etching technology also suffers from irregular etching morphology and high roughness.

[0003] Therefore, how to improve the regularity and reduce the roughness of the manufactured grating-like metal electrodes is a technical problem that needs to be solved in this field. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a method for manufacturing a grating-like structure metal electrode and an electrode that can produce a grating-like structure metal electrode at a specific angle with high morphological regularity and low roughness.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] In a first aspect, embodiments of this application provide a method for manufacturing a grating-like structure metal electrode, including:

[0007] It provides a substrate, a metal layer, and a photomask stacked sequentially;

[0008] An IBE ion beam etching device is used to emit a first particle beam at a first angle to etch the metal layer under the cover of the mask to obtain a coarse grating-like metal electrode.

[0009] The IBE ion beam etching equipment is used to emit a second particle beam at a second angle to etch the coarse grating-like metal electrode under the cover of the mask to obtain the final grating-like metal electrode;

[0010] The first angle is smaller than the second angle. The first angle is the angle formed by the first particle beam and the normal to the substrate surface, and the second angle is the angle formed by the second particle beam and the normal to the substrate surface.

[0011] In one possible implementation, the first angle is greater than or equal to 0° and less than or equal to 20°, and the second angle is greater than or equal to 50° and less than or equal to 80°.

[0012] In one possible implementation, the first particle beam and the second particle beam are obtained in advance through the following steps:

[0013] The first etching gas is introduced into the discharge chamber to obtain the first plasma beam, and the first plasma beam is neutralized to electrical neutrality using a neutralizer to obtain the first particle beam.

[0014] A second etching gas is introduced into the discharge chamber to obtain the second plasma beam, and the second plasma beam is neutralized to electrical neutrality using the neutralizer to obtain the second particle beam.

[0015] In one possible implementation, the first etching gas and the second etching gas comprise:

[0016] At least one of fluorine-based gases, nitrogen, and inert gases.

[0017] In one possible implementation, the material of the metal layer includes:

[0018] Precious metals or precious metal alloys.

[0019] In one possible implementation, the energies of the first and second particle beams are greater than or equal to 200V and less than or equal to 800V.

[0020] In one possible implementation, the material of the mask includes:

[0021] Photoresist, metal or optical media materials.

[0022] In one possible implementation, the substrate is made of the following material:

[0023] At least one of silicon oxide, silicon nitride, or silicon oxynitride.

[0024] Secondly, embodiments of this application provide a grating-like structure metal electrode, including the final grating-like structure metal electrode manufactured using the method described above.

[0025] In one possible implementation, the cross-section of the final grating-like metal electrode is an isosceles triangle.

[0026] Compared with the prior art, this application has the following beneficial effects:

[0027] This application provides a method and structure for manufacturing a grating-like metal electrode. The method includes: providing a substrate, a metal layer, and a mask stacked sequentially; using an IBE ion beam etching apparatus to emit a first particle beam at a first angle to etch the metal layer under the masking of the mask to obtain a coarse grating-like metal electrode; and using the same apparatus to emit a second particle beam at a second angle to etch the coarse grating-like metal electrode under the masking of the mask to obtain a final grating-like metal electrode. The first angle is smaller than the second angle, where the first angle is the angle between the first particle beam and the normal to the substrate surface, and the second angle is the angle between the second particle beam and the normal to the substrate surface. Specifically, utilizing the masking effect and the angled etching characteristic of IBE, a small-angle etching can be used to initially open the metal layer to obtain a coarse grating-like metal electrode, followed by a large-angle etching using the mask to refine the top of the metal layer. As the mask is gradually consumed, the particle beam can gradually etch to the bottom of the metal layer. In this way, the metal contaminants on the sidewalls caused by small-angle etching can be effectively removed, and the metal sidewalls with special angles can be formed due to the etching time difference between the top and bottom of the metal layer, thus obtaining a final grating-like metal electrode with regular morphology and low roughness. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A flowchart illustrating a method for manufacturing a grating-like metal electrode according to an embodiment of this application is shown.

[0030] Figure 2 This illustration shows a schematic diagram of a substrate, a metal layer, and a mask stacked sequentially for fabricating a grating-like metal electrode, according to an embodiment of this application.

[0031] Figure 3 This illustration shows a schematic diagram of the structure during the fabrication of a grating-like metal electrode according to an embodiment of this application;

[0032] Figure 4 This illustration shows a schematic diagram of the structure in another process of fabricating a grating-like metal electrode according to an embodiment of this application;

[0033] Figure 5 This illustration shows a schematic diagram of the structure in another process of fabricating a grating-like metal electrode according to an embodiment of this application;

[0034] Figure 6This illustration shows a schematic diagram of another fabrication process for a grating-like metal electrode provided in an embodiment of this application;

[0035] Figure 7 A schematic diagram of a grating-like metal electrode provided in an embodiment of this application is shown. Detailed Implementation

[0036] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0037] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0038] As described in the background section, the applicant has found that in the integrated circuit (IC) or microelectronics industry, thin films of noble metals such as silver and gold have great potential in forming grating-like metal electrodes due to their low resistivity and good electromigration resistance. However, due to the limited volatility of these noble metals, it is difficult to form grating-like metal electrodes with good morphology through reactive plasma etching. Similarly, wet etching technology also suffers from irregular etching morphology and high roughness.

[0039] Therefore, how to improve the regularity and reduce the roughness of the manufactured grating-like metal electrodes is a technical problem that needs to be solved in this field.

[0040] Specifically, if etching after noble metal deposition could replace the current damascus etching method, the size effect in metallization might be reduced, which would be beneficial for semiconductor chip formation. However, at room temperature, reactive plasma etching is difficult. For example, etching Ag and Au in chloride-based plasma requires increasing the temperature or enhancing the ion bombardment flux / energy, and suffers from severe lateral drilling, inability to control sidewall angles, and poor morphology. Wet etching also faces similar challenges; inert noble metals are difficult to form soluble salts, and even if a few paths are possible, they have inherent defects. For instance, the semiconductor industry commonly uses iodine-potassium iodide-aqueous solution to etch gold films. While this meets the requirements for etching rate uniformity and stability, the remaining electroplated gold film after etching with iodine-potassium iodide-aqueous solution exhibits severely irregular gold layer morphology and high roughness, hindering market application and acceptance.

[0041] To address the aforementioned technical problems, this application provides a method and structure for manufacturing a grating-like metal electrode. The method includes: providing a substrate, a metal layer, and a mask stacked sequentially; using an IBE (Ion Beam Etching) device to emit a first particle beam at a first angle to etch the metal layer under the masking of the mask to obtain a coarse grating-like metal electrode; and using the same device to emit a second particle beam at a second angle to etch the coarse grating-like metal electrode under the masking of the mask to obtain a final grating-like metal electrode. The first angle is smaller than the second angle, where the first angle is the angle between the first particle beam and the normal to the substrate surface, and the second angle is the angle between the second particle beam and the normal to the substrate surface. Specifically, utilizing the masking effect and the angled etching characteristic of IBE, a small-angle etching can be used to initially open the metal layer to obtain a coarse grating-like metal electrode, followed by a larger-angle etching using the mask to refine the top of the metal layer. As the mask is gradually consumed, the particle beam can gradually etch to the bottom of the metal layer. In this way, the metal contaminants on the sidewalls caused by small-angle etching can be effectively removed, and the metal sidewalls with special angles can be formed due to the etching time difference between the top and bottom of the metal layer, thus obtaining a final grating-like metal electrode with regular morphology and low roughness.

[0042] To better understand the technical solution and effects of this application, the specific embodiments will be described in detail below with reference to the accompanying drawings.

[0043] Exemplary methods

[0044] See Figure 1 As shown, this figure is a flowchart of a method for manufacturing a grating-like metal electrode according to an embodiment of this application. The method includes:

[0045] S101: Provides a substrate, a metal layer and a photomask stacked in sequence.

[0046] See Figure 2 The diagram shown is a schematic of a substrate, a metal layer, and a mask stacked sequentially for fabricating a grating-like metal electrode according to an embodiment of this application. In this embodiment, the substrate 1 can be made of a material with a slow etching rate that is close to 0, in order to prevent etching damage to the substrate 1 when etching the metal layer. Optionally, the material of the substrate 1 may include at least one of silicon oxide, silicon nitride, or silicon oxynitride. Depending on the specific etching requirements, the substrate 1 may be made of different materials.

[0047] It should be noted that the dimensional parameters between the substrate 1, the metal layer 2 and the mask 3 can be set according to actual needs. This application embodiment does not make specific limitations here, and can be set by those skilled in the art according to actual conditions.

[0048] Furthermore, since etching of the metal layer 2 is required to form the grating-like metal electrode, this application also includes a mask 3 disposed on the side of the metal layer 2 away from the substrate 1. The material of the mask 3 is a material with a slow etching rate, which is close to zero, to achieve a high selectivity between the metal layer 2 and the mask 3. A higher selectivity can ensure the etching morphology while obtaining an ideal etching depth. The material of the mask 3 may specifically include photoresist, metal, or optical dielectric material. For example, the material of the mask 3 provided in the embodiments of this application may be chromium. Depending on the shape of the grating-like metal electrode to be fabricated, different shapes of mask 3 can be used.

[0049] S102: Using an IBE ion beam etching device, a first particle beam is emitted at a first angle to etch the metal layer under the cover of the mask to obtain a coarse-etched grating-like metal electrode.

[0050] In this embodiment, IBE technology can be used to etch the metal layer 2. Ion beam etching (IBE) is a dry etching process developed in the 1970s. It utilizes ions emitted from an ion source to bombard the target material, causing sputtering on the material surface to remove the material. This purely physical bombardment method has shown great potential in the etching of difficult-to-react precious metals. During the etching process, etching gas is introduced into a quartz cavity discharge chamber, where high-frequency waves excited by an RF coil ionize and generate plasma. Ions are extracted by a grid, focused into a beam, and then neutralized by electrons emitted by a neutralizer into an electrically neutral particle beam with a certain energy, which bombards the wafer surface on the stage to achieve etching. Ion beam etching technology has become an important high-precision pattern transfer technology in the fabrication process of micro- and nano-structures for diffractive optical elements due to its advantages such as good anisotropy, low surface damage, independent control of etching parameters, and ability to etch any material.

[0051] An IBE ion beam etching device can be used to emit a first particle beam at a first angle to etch the metal layer 2 under the cover of the mask 3 to obtain a coarse grating-like metal electrode. That is, in this embodiment of the application, the metal layer 2 can be etched at a small angle first to open part of the metal layer.

[0052] See Figure 3 The diagram shown is a structural schematic of the metal layer 2 after part of it has been opened in an embodiment of this application. The dotted line with arrows represents the first particle beam, and the angle A formed by the first particle beam and the normal to the surface of the substrate 1 is the first angle. When etching the metal layer 2 with the first particle beam at the first angle, the downward etching to open the metal layer 2 and the removal of the deposit are carried out simultaneously. While gradually opening the metal layer 2, it is ensured that repeated metal deposition will not affect the steepness, thereby obtaining a nearly vertical morphology of the metal layer 2.

[0053] In one possible implementation, the first angle can be set to be greater than or equal to 0° and less than or equal to 20°, and the energy of the first particle beam can be greater than or equal to 200V and less than or equal to 800V, to initially etch open the metal layer 2 and obtain a coarse-etched grating-like metal electrode. See [link to relevant documentation]. Figure 4 As shown, the angle between the sidewall of the metal layer 2 of the coarse-grained grating structure metal electrode and the substrate 1 is θ1.

[0054] In one possible implementation, to obtain the first particle beam, a first etching gas can be introduced into the discharge chamber to obtain a first plasma beam. The first plasma beam is then neutralized to electrical neutrality using a neutralizer to obtain the first particle beam. Specifically, the first etching gas provided in this application embodiment may include at least one of fluorine-based gas, nitrogen, and inert gas, such as at least one of CHF3, CF4, SF6, Ar, and N2. When the first etching gas includes two or more gases, the ratio between the various types of etching gases can be adjusted by those skilled in the art according to the actual situation.

[0055] The particle beam provided in this application embodiment has a chemical reaction function and a certain physical bombardment function. When the particle beam interacts with the metal layer 2, physical and chemical reactions occur simultaneously. By adjusting the energy (BMV, BeamVoltage) of the particle beam, the bombardment intensity, reaction rate, etc. can be adjusted. In one possible implementation, the energy of the first particle beam is greater than or equal to 200V and less than or equal to 800V.

[0056] S103: The IBE ion beam etching equipment is used to emit a second particle beam at a second angle to etch the coarse grating-like metal electrode under the cover of the mask to obtain the final grating-like metal electrode; the first angle is smaller than the second angle, the first angle is the angle formed by the first particle beam and the normal of the substrate surface, and the second angle is the angle formed by the second particle beam and the normal of the substrate surface.

[0057] In this embodiment, to improve the regularity of the grating-like metal electrode and reduce its surface roughness, IBE technology can be used to continue etching the metal layer 2. At this time, a large angle, i.e., a second angle, is used for etching. The top of the metal layer 2 is first modified using a mask 3. As the mask 3 is gradually consumed, the second particle beam can gradually etch to the bottom of the metal layer 2. This effectively removes the sidewall metal contaminants generated by small-angle etching, and simultaneously forms metal sidewalls with a special angle due to the etching time difference between the top and bottom of the metal layer 2.

[0058] When the incident angle of the selected second particle beam is appropriate, such that the second particle beam etches precisely to the interface between metal layer 2 and mask layer 3, the etched area of ​​metal layer 2 increases as mask layer 3 is consumed. Because the etching rate of metal layer 2 differs at large angles compared to small angles, an angle transition occurs at the etched / unetched interface, where the main etching angle θ1 > the modification angle θ2. (See [reference needed]). Figure 5 As shown.

[0059] Etching of metal layer 2 can continue. As the time for the second particle beam to modify the sidewalls of metal layer 2 continues to increase, and the aspect ratio of the mask 3 is appropriate, a grating-like metal electrode structure will be formed. For example... Figure 6 As shown, the metal on both sides and the mask are continuously consumed, and the second particle beam continues to etch the metal layer 2 at a second angle under the cover of the mask 3. Figure 6 The oblique arrow in the middle represents the second particle beam, and the angle B formed by it and the normal to the surface of substrate 1 is the second angle.

[0060] A second particle beam at a second angle continuously etches the metal layer 2, consuming the metal and mask on both sides until it shrinks to a single point. In one possible implementation, due to the IBE rotation, the metal layer 2 exhibits a pyramidal shape and an isosceles triangular morphology in cross-section. This results in a final grating-like structure with highly regular metal electrodes and low surface roughness. (See [reference]). Figure 7 As shown. In one possible implementation, the cross-section of the final grating-like structure metal electrode provided in this application embodiment can also be an isosceles trapezoidal shape. The specific shape can be adjusted by those skilled in the art according to the actual situation, and this application embodiment does not make specific limitations here.

[0061] In one possible implementation, the second angle can be set to be greater than or equal to 50° and less than or equal to 800°, and the energy of the second particle beam can be greater than or equal to 200V and less than or equal to 800V, in order to etch a rough grating-like metal electrode to obtain the final grating-like metal electrode.

[0062] Optionally, the bias voltage used to accelerate the first and second particle beams can be 80V.

[0063] In one possible implementation, to obtain the second particle beam, a second etching gas can be introduced into the discharge chamber to obtain a second plasma beam. The second plasma beam is then neutralized to electrical neutrality using a neutralizer to obtain the second particle beam. Specifically, the second etching gas provided in this application embodiment may include at least one of fluorine-based gas, nitrogen, and inert gas, such as at least one of CHF3, CF4, SF6, Ar, and N2. When the second etching gas includes two or more gases, the ratio between the various types of etching gases can be adjusted by those skilled in the art according to the actual situation.

[0064] The particle beam provided in this application embodiment has both chemical reaction function and a certain physical bombardment function. When the particle beam interacts with the metal layer 2, physical and chemical reactions occur simultaneously. By adjusting the energy (BMV, BeamVoltage) of the particle beam, the bombardment intensity, reaction rate, etc. can be adjusted. In one possible implementation, the energy of the second particle beam is greater than or equal to 200V and less than or equal to 800V, depending on the required etching rate and the characteristics of the material itself.

[0065] This application provides a method for manufacturing a grating-like structure metal electrode. The method includes: providing a substrate, a metal layer, and a mask stacked sequentially; using an IBE (In-Beam Etching) device to emit a first particle beam at a first angle to etch the metal layer under the masking of the mask to obtain a coarse grating-like structure metal electrode; and using the same device to emit a second particle beam at a second angle to etch the coarse grating-like structure metal electrode under the masking of the mask to obtain a final grating-like structure metal electrode. The first angle is smaller than the second angle, where the first angle is the angle between the first particle beam and the normal to the substrate surface, and the second angle is the angle between the second particle beam and the normal to the substrate surface. Specifically, utilizing the masking effect and the angled etching characteristic of IBE, a small-angle etching can be used to initially open the metal layer to obtain a coarse grating-like structure metal electrode, followed by a larger-angle etching using the mask to refine the top of the metal layer. As the mask is gradually consumed, the particle beam can gradually etch to the bottom of the metal layer. In this way, the metal contaminants on the sidewalls caused by small-angle etching can be effectively removed, and the metal sidewalls with special angles can be formed due to the etching time difference between the top and bottom of the metal layer, thus obtaining a final grating-like metal electrode with regular morphology and low roughness.

[0066] Exemplary Structure

[0067] This application also provides a grating-like structure metal electrode, including the final grating-like structure metal electrode manufactured using the above-described method.

[0068] In one possible implementation, the cross-section of the final grating-like metal electrode is an isosceles triangle, see [reference needed]. Figure 7 As shown.

[0069] This application provides a grating-like structure metal electrode. The method for manufacturing this structure includes: providing a substrate, a metal layer, and a mask stacked sequentially; using an IBE (Ion Beam Etching) device to emit a first particle beam at a first angle to etch the metal layer under the masking of the mask to obtain a coarse grating-like structure metal electrode; and using the same device to emit a second particle beam at a second angle to etch the coarse grating-like structure metal electrode under the masking of the mask to obtain a final grating-like structure metal electrode. The first angle is smaller than the second angle, where the first angle is the angle between the first particle beam and the normal to the substrate surface, and the second angle is the angle between the second particle beam and the normal to the substrate surface. That is, utilizing the masking effect of the mask and the angled etching unique to IBE, a small-angle etching can be used first to initially open the metal layer to obtain a coarse grating-like structure metal electrode, and then a large-angle etching can be used to refine the top of the metal layer using the masking effect. As the mask is gradually consumed, the particle beam can gradually etch to the bottom of the metal layer. In this way, the metal contaminants on the sidewalls caused by small-angle etching can be effectively removed, and the metal sidewalls with special angles can be formed due to the etching time difference between the top and bottom of the metal layer, thus obtaining a final grating-like metal electrode with regular morphology and low roughness.

[0070] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, structural embodiments are generally similar to method embodiments and are therefore described simply; relevant details can be found in the descriptions of the method embodiments.

[0071] The above description is merely a preferred embodiment of this application. Although this application has disclosed preferred embodiments above, it is not intended to limit this application. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this application using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of this application. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall still fall within the protection scope of the technical solutions of this application.

Claims

1. A method for manufacturing a grating-like metal electrode, characterized in that, include: It provides a substrate, a metal layer, and a photomask stacked sequentially; An IBE ion beam etching device is used to emit a first particle beam at a first angle to etch the metal layer under the cover of the mask to obtain a coarse-etched grating structure metal electrode; in the coarse-etched grating structure metal electrode, the angle between the sidewall of the metal layer and the substrate is θ1; The IBE ion beam etching equipment emits a second particle beam at a second angle to etch the coarse grating-like metal electrode under the cover of the mask to obtain the final grating-like metal electrode. During the etching process using the second particle beam, the top of the metal layer is first modified by the mask, so that the sidewalls of the metal layer form an angle transition at the etched / unetched boundary, with the main etching forming angle θ1 > the modification forming angle θ2. The second particle beam continues to modify the sidewalls of the metal layer. As the mask is gradually consumed, the second particle beam can gradually etch to the bottom of the metal layer, thereby obtaining the final grating-like metal electrode. The cross-section of the final grating-like metal electrode is an isosceles triangle or an isosceles trapezoid. The first angle is smaller than the second angle. The first angle is the angle formed by the first particle beam and the normal to the substrate surface, and the second angle is the angle formed by the second particle beam and the normal to the substrate surface.

2. The method according to claim 1, characterized in that, The first angle is greater than or equal to 0° and less than or equal to 20°, and the second angle is greater than or equal to 50° and less than or equal to 80°.

3. The method according to claim 1, characterized in that, It also includes obtaining the first particle beam and the second particle beam in advance through the following steps: A first etching gas is introduced into the discharge chamber to obtain a first plasma beam, and a neutralizer is used to neutralize the first plasma beam to obtain the first particle beam. A second etching gas is introduced into the discharge chamber to obtain a second plasma beam, and the second plasma beam is neutralized to electrical neutrality using the neutralizer to obtain the second particle beam.

4. The method according to claim 3, characterized in that, The first etching gas and the second etching gas include: At least one of fluorine-based gases, nitrogen, and inert gases.

5. The method according to claim 1, characterized in that, The material of the metal layer includes: Precious metals or precious metal alloys.

6. The method according to claim 1, characterized in that, The material of the photomask includes: Photoresist, metal or optical media materials.

7. The method according to claim 1, characterized in that, The substrate is made of the following materials: At least one of silicon oxide, silicon nitride, or silicon oxynitride.

8. A grating-like metal electrode, characterized in that, include: The final grating-like structure metal electrode manufactured using the method described in any one of claims 1-7.

9. The electrode according to claim 8, characterized in that, The cross-section of the final grating-like structure metal electrode has an isosceles triangular shape.

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