A photolithography method

Abstract

The application provides a photolithography method. The method comprises the following steps: cleaning and depositing: cleaning a semiconductor substrate and depositing a growth medium on the surface of the semiconductor substrate; photolithography and metal evaporation: coating a photoresist on the surface of the growth medium, exposing and developing the surface of the growth medium by using a photolithography machine and a photolithography plate to form an exposure pattern, evaporating a metal film on the surface of the exposure pattern, removing the photoresist, and forming a metal mask pattern; repeating the photolithography and metal evaporation operation for N times; wherein N is greater than or equal to 2, at least two photolithography plates are used in the N times of photolithography and metal evaporation operation, and there is an overlapping area between the photolithography patterns corresponding to the photolithography plates, the shape and size of the area are determined by the target shape and size of the medium etching; etching and removing the metal: etching the growth medium by using the metal film as a mask, removing the metal film, and forming a medium etching pattern. The application combines multiple misaligned photolithography and metal evaporation mask to break through the line width limitation of the existing photolithography machine and obtain a small size line width pattern.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, and in particular to a photolithography method. BACKGROUND

[0002] High frequency miniaturization is an important direction of development of semiconductor devices and circuits. With the widespread application of wireless communication, to meet the demand for higher bandwidth, the line width required by the chip tends to be smaller in size to increase the radio frequency characteristics of the chip. The precision of the photolithography machine is an important factor affecting the line width. Although the electron beam photolithography machine and the step-and-scan photolithography machine can meet the line width requirement, they are expensive and have a low popularity rate in research institutions such as colleges. In order to break free from the limitations of the equipment and achieve small-size line width, it is urgent to develop a new photolithography technology. SUMMARY

[0003] Embodiments of the present application provide a photolithography method to break through the line width limitation of the existing photolithography machine and obtain a small-size line width pattern.

[0004] Embodiments of the present application provide a photolithography method, which comprises:

[0005] Cleaning and deposition: cleaning a semiconductor substrate and depositing a growth medium on the surface of the semiconductor substrate;

[0006] Photolithography and metal evaporation: coating a photoresist on the surface of the growth medium, exposing and developing the surface of the growth medium by using a photolithography machine and a photomask to form an exposure pattern, evaporating a metal film on the surface of the exposure pattern, removing the photoresist, and forming a metal mask pattern;

[0007] Repeating the photolithography and metal evaporation operation N times; wherein N is greater than or equal to 2, and at least two photomasks are used in the N times of photolithography and metal evaporation operation, the photolithography patterns corresponding to the at least two photomasks have a coincident area, and the shape and size of the coincident area are determined by the target shape and size of the medium etching;

[0008] Etching and removing metal: using the metal film on the surface of the metal mask pattern as a mask to etch the growth medium and remove the metal film to form a medium etching pattern.

[0009] In a possible implementation, the growth medium is deposited on the surface of the semiconductor substrate by using a chemical vapor deposition method.

[0010] In a possible implementation, the growth medium is a silicon nitride layer or a silicon oxide layer.

[0011] In a possible implementation, the photoresist is removed by using a wet photoresist stripper.

[0012] In a possible implementation, an electron beam evaporation vacuum coating machine is used to evaporate the metal film.

[0013] In a possible implementation, a plasma etching machine is used to etch the growth medium.

[0014] In a possible implementation, the photoetching machine is a contact photoetching machine.

[0015] In a possible implementation, the photoetching machine is a proximity photoetching machine.

[0016] The photoetching method provided by the present application has the following advantages:

[0017] Different from the conventional method, the photoetching method provided by the present application combines multiple misaligned photoetching and evaporated metal mask, so that the line width limit of the existing photoetching machine can be broken without using a higher precision photoetching machine, and a small size line width pattern can be obtained. Moreover, the present application is applicable to all photoetching technologies, especially to micron level contact photoetching technology, and can reduce the minimum size of the target pattern to nanometer level, which is an effective method for realizing high frequency device development. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 is a structure schematic diagram of the semiconductor substrate after depositing and growing the growth medium provided by the present application;

[0020] Figure 2 is a structure schematic diagram after the first coating of photoresist provided by the present application;

[0021] Figure 3 is a structure schematic diagram after the first exposure and development provided by the present application;

[0022] Figure 4 is a structure schematic diagram after the first evaporation of metal film provided by the present application;

[0023] Figure 5 is a structure schematic diagram after the first removal of photoresist provided by the present application;

[0024] Figure 6 is a structure schematic diagram after the second coating of photoresist provided by the present application;

[0025] Figure 7 is a structural schematic diagram of the structure after the second exposure and development provided by the embodiment of the present application;

[0026] Figure 8 is a structural schematic diagram of the structure after the second metal thin film evaporation provided by the embodiment of the present application;

[0027] Figure 9 is a structural schematic diagram of the structure after the second photoresist removal provided by the embodiment of the present application;

[0028] Figure 10 is a structural schematic diagram of the structure after the etching of the growth medium provided by the embodiment of the present application;

[0029] Figure 11 is a structural schematic diagram of the medium etching pattern provided by the embodiment of the present application.

[0030] In the above description, for the purpose of explanation and not for the purpose of limitation, specific details are set forth, such as specific system structures, techniques, and so on, in order to thoroughly understand the embodiments of the present application. However, it should be clear for those skilled in the art that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known matters are omitted in order not to obscure the description of the present application with unnecessary details. DETAILED DESCRIPTION

[0031] In the following description, for the purpose of explanation and not for the purpose of limitation, specific details are set forth, such as specific system structures, techniques, and so on, in order to thoroughly understand the embodiments of the present application. However, it should be clear for those skilled in the art that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known matters are omitted in order not to obscure the description of the present application with unnecessary details.

[0032] In order to make the objects, technical solutions and advantages of the present application clearer, the following will be described by specific embodiments in conjunction with the accompanying drawings.

[0033] The embodiment of the present application provides a photoetching method, comprising:

[0034] cleaning and depositing: cleaning a semiconductor substrate, and depositing a growth medium on the surface of the semiconductor substrate;

[0035] photoetching and metal evaporation: coating a photoresist on the surface of the growth medium, exposing and developing the surface of the growth medium by using a photoetching machine and a photoetching plate, forming an exposure pattern, evaporating a metal thin film on the surface of the exposure pattern, removing the photoresist, and forming a metal mask pattern;

[0036] repeating the photoetching and metal evaporation operation N times; wherein N≧2, and at least two photoetching plates are used in the N times of photoetching and metal evaporation operation, and there is an overlapping area between the photoetching patterns corresponding to the at least two photoetching plates, and the shape and size of the overlapping area are determined by the target shape and size of the medium etching;

[0037] Etching and removing metal: taking the metal film on the surface of the metal mask pattern as a mask, etching the growth medium, removing the metal film, and forming a medium etching pattern.

[0038] The photolithography method provided by the embodiment of the present application has a coincident area between the corresponding photolithography patterns on the photolithography plates used in two adjacent times of photolithography when the photolithography and metal evaporation operations are repeatedly performed, and the shape and size of the coincident area are determined according to the shape and size of the target medium etching pattern. The target medium etching pattern obtained can be used as a medium gate root pattern or a Schottky contact area pattern, which is not limited in the present application.

[0039] The photolithography method provided by the embodiment of the present application can effectively reduce the line width of the target medium etching pattern, obtain a small-size line width pattern, effectively reduce the error of the target medium etching pattern, break through the line width limitation of the existing photolithography machine without using a higher-precision photolithography machine, and obtain a smaller-size line width pattern while controlling the research and development cost. Moreover, the present application is suitable for all photolithography technologies, especially for micron-level contact photolithography technology, and can reduce the minimum size of the target pattern to nanometer level, which is an effective method for realizing high-frequency device development.

[0040] The embodiment of the present application takes twice misaligned photolithography and metal evaporation as an example to illustrate the technical solution of the present application, which is not limited thereto. Referring to Figures 1-11 The photolithography method provided by the embodiment of the present application first cleans a semiconductor substrate 1 and deposits a layer of growth medium 2 on the surface thereof; then coats photoresist 3 on the surface of the growth medium 2, exposes and develops the surface of the growth medium 2 by using a photolithography machine and a first photolithography plate to form an exposure pattern; evaporates a metal film 4 on the surface of the exposure pattern, and removes the photoresist 3 by using dry etching or wet cleaning to form a metal mask pattern; then coats photoresist 3 on the surface of the metal mask pattern for the second time, exposes and develops the surface of the metal mask pattern by using a photolithography machine and a second photolithography plate to form a new exposure pattern; evaporates a metal film 4 on the surface of the new exposure pattern for the second time, and removes the photoresist 3 by using dry etching or wet cleaning to form a new metal mask pattern; finally, takes the metal film 4 of the new metal mask pattern as a mask, etches the growth medium 2 by using dry etching or wet etching, removes the metal film 4 on the surface of the growth medium 2, and forms a target medium etching pattern.

[0041] The photoetching method provided in the above embodiment of the present application has overlapping regions between corresponding photoetching patterns on the first photoetching plate and the second photoetching plate. If the corresponding photoetching patterns on the first photoetching plate are divided into overlapping regions and misaligned regions, then through the two photoetching processes, the shape and size of the overlapping regions are the shape and size of the target medium etching pattern, and the shape and size of the misaligned regions are the shape and size of the medium etching pattern reduced by the two photoetching processes. The photoetching method provided in the embodiment of the present application uses two misaligned photoetching processes and a metal evaporation mask to break through the line width limitation of the existing photoetching machine and obtain a small-size line width pattern without using a higher-precision photoetching machine.

[0042] In a possible implementation, the growth medium is deposited on the surface of the semiconductor substrate by a chemical vapor deposition method.

[0043] In the embodiment, the growth medium 2 is deposited on the surface of the semiconductor substrate 1 by a chemical vapor deposition method.

[0044] In a possible implementation, the growth medium is a silicon nitride layer or a silicon oxide layer.

[0045] In the embodiment, the growth medium 2 can be a silicon nitride layer or a silicon oxide layer.

[0046] In a possible implementation, a wet stripping machine is used to remove the photoresist.

[0047] In the embodiment, the wet stripping machine is used to remove the photoresist 3, and a dry plasma etching method can also be used to remove the photoresist 3, which is not limited in the present application.

[0048] In a possible implementation, an electron beam evaporation vacuum coating machine is used to evaporate a metal film.

[0049] In the embodiment, the electron beam evaporation vacuum coating machine is used to evaporate the metal film 4.

[0050] In a possible implementation, a plasma etching machine is used to etch the growth medium.

[0051] In the embodiment, the plasma etching machine is used to etch the growth medium 2.

[0052] In a possible implementation, the photoetching machine is a contact type photoetching machine.

[0053] In the embodiment, the photoetching machine can be a contact type photoetching machine.

[0054] In a possible implementation, the photoetching machine is a proximity type photoetching machine.

[0055] In the embodiment, the photoetching machine can be a proximity type photoetching machine.

[0056] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A photolithography method, characterized in that: include: Cleaning and deposition: cleaning the semiconductor substrate and depositing a growth medium on the surface of the semiconductor substrate; Photolithography and metal evaporation: coating the surface of the growth medium with photoresist, exposing and developing the surface of the growth medium using a photolithography machine and a photomask to form an exposure pattern, evaporating a metal film on the surface of the exposure pattern, removing the photoresist, and forming a metal mask pattern; Repeating N times of photolithography and metal evaporation operations; wherein N ≥ 2, and at least two photomasks are used during the N times of photolithography and metal evaporation operations, and there is an overlapping area between the photolithographic patterns corresponding to the at least two photomasks, and the shape and size of the overlapping area are determined by the target shape and size of the dielectric etching; Etching and removing metal: using the metal film on the surface of the metal mask pattern as a mask, etching the growth medium, removing the metal film, and forming a medium etching pattern; The shape and size of the dielectric etching pattern are the shape and size of the overlapping area.

2. The photolithography method according to claim 1, wherein: The growth medium is deposited on the surface of the semiconductor substrate by using a chemical vapor deposition method.

3. The photolithography method according to claim 2, wherein: The growth medium is a silicon nitride layer or a silicon oxide layer.

4. The photolithography method according to claim 1, wherein: Use a wet stripper to remove the photoresist.

5. The photolithography method according to claim 1, wherein: Electron beam evaporation vacuum coating machine is used to evaporate metal thin film.

6. The photolithography method according to claim 1, wherein: A plasma etcher is used to etch the growth medium.

7. The photolithography method according to any one of claims 1 to 6, wherein: The photolithography machine is a contact photolithography machine.

8. The photolithography method according to any one of claims 1 to 6, wherein: The photolithography machine is a proximity photolithography machine.

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