Metal etching method

Abstract

The invention is applicable to the technical field of metal electrode preparation, and particularly relates to a metal etching method, which comprises the following steps of: performing metal growth on a clean substrate to obtain a substrate covered with a metal layer; generating a mask layer on the metal layer above the substrate, and performing photoetching treatment; after the metal layer is etched, the substrate is etched; and generating a passivation layer on the etched substrate, and etching an opening on the passivation layer to expose the required metal to obtain a finished product. According to the metal etching method provided by the invention, a stripping process is replaced by metal etching, the yield loss caused by the stripping process is avoided, parameter adjustment is carried out according to the used equipment, reasonable distribution and layout are carried out before the process is carried out, the method is simple, meanwhile, the process steps are shortened, and the operability is high.

Description

Technical Field

[0001] The invention belongs to the technical field of metal electrode preparation, and in particular relates to a metal etching method. Background Art

[0002] Electrode production is an important process in the semiconductor device manufacturing process. In many academic studies and process improvements, various studies have been conducted on how to prepare excellent electrodes. Since electrode growth is greatly affected by lithography and equipment, although there are many existing processes, whether they are suitable for current process conditions is an important issue. In addition, the complex structure on the device surface after etching further increases the difficulty of electrode lithography, resulting in frequent problems with electrode growth. Therefore, the present invention proposes a new electrode preparation process method to avoid the above problems. The morphology and line width after etching mentioned here include the morphology after etching of passivation layers such as silicon oxide and silicon nitride, and can also be the morphology after etching of other metal layers, GaAs and other material layers. The electrodes include a variety of metal shapes and types.

[0003] Currently, due to the limitations of the thickness of the grown metal and the equipment, metal pattern lithography needs to use single-layer or double-layer adhesive technology. However, after all the processes, due to the complex surface structure and many ups and downs, the metal lithography yield will be seriously affected, resulting in irreversible defects in metal growth, which will cause the device performance to drop significantly or even be scrapped. This method can solve the problems of no suitable metal growth equipment and difficulty in metal lithography. Summary of the invention

[0004] The purpose of the present invention is to provide a metal etching method, aiming to solve the problem in the prior art that the metal lithography yield is seriously affected due to the complex surface structure and many ups and downs, resulting in irreversible defects in metal growth, which leads to a significant decline in device performance or even scrapping.

[0005] The present invention is achieved by a metal etching method, the method comprising:

[0006] Performing metal growth on a clean substrate to obtain a substrate covered with a metal layer;

[0007] Generating a mask layer on the metal layer above the substrate and performing a photolithography process;

[0008] After etching the metal layer, etching the substrate;

[0009] A passivation layer is generated on the etched substrate, and an opening is etched on the passivation layer to expose the required metal to obtain a finished product.

[0010] Preferably, in the step of growing metal on a clean substrate, the type of the grown metal is any one of Ti, Pt, Pd, Al, Au, Zn and In.

[0011] Preferably, the mask layer is silicon oxide, silicon nitride, aluminum oxide or silicon oxynitride.

[0012] Preferably, when etching is performed, a metal etcher is used for etching or plasma bombardment is used for physical etching.

[0013] Preferably, during the etching of the substrate, a gas system that does not react with the metal is selected, and the metal surface is protected by a photoresist during the etching process.

[0014] Preferably, the substrate is covered with an InAs / GaSb material layer.

[0015] Another object of the present invention is to provide an application of the metal etching method as described above in the manufacture of metal electrodes.

[0016] The metal etching method provided by the present invention replaces the stripping process with metal etching, thereby avoiding the yield loss caused by the stripping process, adjusting parameters according to the equipment used, and reasonably allocating the layout before the process. The method is simple, shortens the process steps, and has strong operability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of a process flow of a metal etching method provided by an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of a first finished product of the metal etching method provided by an embodiment of the present invention;

[0019] Figure 3 A schematic diagram of a second finished product of the metal etching method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0021] Exposure and development: A micro-nano processing technology that mainly involves ultraviolet lithography, which is to apply photoresist on the surface of the substrate sample, and then irradiate ultraviolet light through the mask to the substrate surface, use photochemical reactions to change the properties of the photoresist exposed to light, and then dissolve the area that reacts with light into a specific solution to achieve the purpose of making a specific pattern on the substrate.

[0022] Lift-off technology refers to the process in which, after the substrate is coated with photoresist, exposed and developed, a photoresist with a certain pattern is used as a mask to deposit the required materials, such as metals, through evaporation and other methods. Then, while removing the photoresist, the non-required materials on the photoresist film are stripped off, leaving only the material structure with the original pattern on the substrate.

[0023] Etching: It is an etching process that transfers the photoresist pattern obtained by lithography to the thin film on the surface of the wafer. That is, the covering and protective effect of the photoresist film is used to remove the thin film without photoresist protection by chemical reaction or physical action to complete the purpose of pattern transfer.

[0024] like Figure 1 FIG. 1 is a flow chart of a metal etching method provided by an embodiment of the present invention, wherein the method comprises:

[0025] Performing metal growth on a clean substrate to obtain a substrate covered with a metal layer;

[0026] Generating a mask layer on the metal layer above the substrate and performing a photolithography process;

[0027] After etching the metal layer, etching the substrate;

[0028] A passivation layer is generated on the etched substrate, and an opening is etched on the passivation layer to expose the required metal to obtain a finished product.

[0029] In this embodiment, a metal etching process is utilized to change upward growth into downward etching, firstly, metal is grown on the surface of the substrate to achieve full coverage, a desired morphology is prepared by photolithography, and then the morphology is inherited by metal etching, and finally a passivation layer is grown to cover the material sidewalls and the metal surface. Specifically, the process includes first growing metal on the surface of a substrate (a material layer is covered on the surface of the substrate), optionally growing a mask layer on the metal surface to protect the metal, etching the metal after photolithography patterning to expose the InAs / GaSb material region, and then etching the material. After the material layer is etched, a passivation layer is grown to cover the metal and the material layer. According to the method of the claim, a photolithographic opening is formed in the passivation layer to expose the desired metal.

[0030] The growth metal types include but are not limited to Ti, Pt, Pd, Al, Au, Zn, In, etc.

[0031] Growth mask types include silicon oxide (SiOx), silicon nitride (SiNx), aluminum oxide or silicon oxynitride (SiON), etc.

[0032] There are two methods of metal etching: one is metal etching machine etching, which uses reactive etching; the other is plasma bombardment, which uses physical etching.

[0033] Material etching requires the selection of a gas system that does not react with metals, and the metal surface is protected by photoresist during the etching process.

[0034] In one embodiment of the present invention, a metal layer is first grown on a clean substrate, a growth mask is selected on the substrate after the metal is grown or a photoresist mask is used to perform metal etching, the substrate after metal etching is de-bonded and cleaned, a passivation layer protective material is grown on the cleaned substrate, a photolithography process is performed on the grown passivation layer, and the metal in the desired area is exposed by passivation opening etching.

[0035] like Figure 2 As shown, growing metallic aluminum:

[0036] 1. First grow 1 micron of metallic aluminum on a clean substrate.

[0037] 2. Grow a silicon oxide mask on the substrate after growing metallic aluminum.

[0038] 3. Perform photolithography on the silicon oxide mask to prepare the required pattern.

[0039] 4. After photolithography, the silicon oxide is etched first, and then the aluminum layer and InAs / GaSb material are etched.

[0040] like Figure 3 As shown, the growth of metal aluminum

[0041] 1. First grow 300nm gold on a clean substrate.

[0042] 2. Make waveguide lithography on the substrate after growing gold, using a Pr mask.

[0043] 3. After baking, the gold is directly etched, and Ar is used for physical bombardment etching during the etching process to obtain the desired structure.

[0044] The present invention also provides an application of the metal etching method described above in manufacturing a metal electrode.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A metal etching method, characterized in that: The method comprises: Growing metal on a clean substrate to obtain a substrate covered with a metal layer; Generating a mask layer on the metal layer above the substrate and performing a photolithography process; After etching the metal layer, etching the substrate; A passivation layer is generated on the etched substrate, and an opening is etched on the passivation layer to expose the required metal to obtain a finished product.

2. The metal etching method according to claim 1, characterized in that: In the step of growing metal on a clean substrate, the type of the grown metal is any one of Ti, Pt, Pd, Al, Au, Zn and In.

3. The metal etching method according to claim 1, characterized in that: The mask layer is silicon oxide, silicon nitride, aluminum oxide or silicon oxynitride.

4. The metal etching method according to claim 1, characterized in that: When etching is performed, a metal etcher is used for etching or plasma bombardment is used for physical etching.

5. The metal etching method according to claim 1, characterized in that: During the etching of the substrate, a gas system that does not react with the metal is selected, and the metal surface is protected by a photoresist during the etching process.

6. The metal etching method according to claim 1, characterized in that: The substrate is covered with an InAs / GaSb material layer.

7. Use of the metal etching method according to any one of claims 1 to 6 in manufacturing metal electrodes.

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