Preparation method of Y-shaped gate and prepared Y-shaped gate

Abstract

The invention provides a preparation method of a Y-shaped gate and the prepared Y-shaped gate, which can be applied to the technical field of microelectronics. The method comprises the following steps: performing deep ultraviolet irradiation treatment on first electron beam photoresist on the upper surface of a substrate to obtain a first photoresist layer; spin-coating second electron beam photoresist on the surface of the first photoresist layer to obtain a second photoresist layer; performing first exposure and development operation on the first photoresist layer and the second photoresist layer to obtain a gate cap structure of a Y-shaped gate; performing second exposure and development operation on the first photoresist layer after the first exposure and development operation to obtain a gate pin structure of the Y-shaped gate; and filling the gate cap structure and the gate pin structure with a target metal material by using a metal evaporation method to obtain the Y-shaped gate.

Description

Technical Field

[0001] The present disclosure relates to the field of microelectronic technology, and in particular to a method for preparing a Y-type gate and a Y-type gate prepared therefrom. Background Art

[0002] In semiconductor technology, the morphology of the metal gate in a field effect transistor (FET) can not only change the gate resistance, but also affect the parasitic capacitance between the gate and the source and drain, thus having a very significant impact on the operating frequency and noise of the device. Up to now, the T-type gate and Y-type gate are basically prepared to reduce the parasitic effect between the gate and the source and drain to achieve the improvement of device performance. Compared with the T-type gate, the Y-type gate has the characteristics of high mechanical strength and small parasitic capacitance, so it has a higher application prospect.

[0003] However, in the related art, compared with the mature preparation process of T-type gate, the preparation of Y-type gate has the problems of fewer preparation schemes, high process requirements and great preparation difficulty. Summary of the invention

[0004] In view of the above problems, the present disclosure provides a method for preparing a Y-type gate and a Y-type gate prepared therefrom.

[0005] According to a first aspect of the present disclosure, a method for preparing a Y-type gate is provided, comprising:

[0006] Performing deep ultraviolet light irradiation treatment on the first electron beam photoresist located on the upper surface of the substrate to obtain a first photoresist layer;

[0007] Spin coating a second electron beam photoresist on the surface of the first photoresist layer to obtain a second photoresist layer, wherein the second electron beam photoresist has a higher sensitivity than the first electron beam photoresist;

[0008] Performing a first exposure and development operation on the first photoresist layer and the second photoresist layer to obtain a gate cap structure of a Y-type gate;

[0009] Performing a second exposure and development operation on the first photoresist layer after the first exposure and development operation to obtain the gate foot structure of the Y-type gate;

[0010] The target metal material is filled into the gate cap structure and the gate foot structure by using a metal evaporation method to obtain the Y-type gate.

[0011] According to an embodiment of the present disclosure, the first electron beam photoresist located on the upper surface of the substrate is subjected to deep ultraviolet light irradiation treatment to obtain a first photoresist layer, including:

[0012] The molecular weight of the first electron beam photoresist is degraded by the deep ultraviolet light irradiation treatment to obtain the first photoresist layer, wherein the degradation degree of the molecular weight of the first electron beam photoresist in the first photoresist layer gradually decreases from top to bottom.

[0013] According to an embodiment of the present disclosure, the first exposure and development operation is performed on the first photoresist layer and the second photoresist layer to obtain a gate cap structure of a Y-type gate, including:

[0014] Based on the first exposure size set for the second photoresist layer, performing an exposure operation on the second photoresist layer to obtain a first exposure area of ​​the second photoresist layer;

[0015] A development operation is performed on the first exposure area to obtain the development structure of the second photoresist layer and the gate cap structure of the first photoresist layer.

[0016] According to an embodiment of the present disclosure, the development operation is performed on the first exposure area to obtain the development structure of the second photoresist layer and the gate cap structure of the first photoresist layer, including:

[0017] Using a first developer, developing the first exposure area of ​​the second photoresist layer to obtain the developed structure of the second photoresist layer; and

[0018] After obtaining the above-mentioned development structure, the above-mentioned first photoresist layer is developed using the above-mentioned first developer based on the degree of degradation of the molecular weight of the above-mentioned first electron beam photoresist in the above-mentioned first photoresist layer to obtain the above-mentioned gate cap structure, wherein the above-mentioned gate cap structure is an inverted trapezoidal structure.

[0019] According to an embodiment of the present disclosure, the first photoresist layer subjected to the first exposure and development operation is subjected to a second exposure and development operation to obtain the gate foot structure of the Y-type gate, including:

[0020] Based on the second exposure size set for the first photoresist layer, performing an exposure operation on the first photoresist layer after the first exposure and development operation, to obtain a second exposure area of ​​the second photoresist layer;

[0021] The second exposure area is developed using a second developer to obtain the gate foot structure.

[0022] According to an embodiment of the present disclosure, the target metal material includes a first target metal material and a second target metal material, and the target metal material is filled into the gate cap structure and the gate foot structure by a metal evaporation method to obtain the Y-type gate, including:

[0023] Using a metal evaporation method, forming an adhesion layer composed of the first target metal material on the surface of the substrate located in the gate foot structure;

[0024] The second target metal material is filled into the gate cap structure and the gate foot structure by using the metal evaporation method to obtain a target structure, wherein the target structure includes the Y-type gate composed of the first target metal material and the second target metal material.

[0025] According to an embodiment of the present disclosure, the method for preparing the Y-type gate further includes:

[0026] The first photoresist layer, the second photoresist layer and the metal layer on the second photoresist layer obtained by the metal evaporation method in the target structure are peeled off to obtain the Y-type gate.

[0027] According to an embodiment of the present disclosure, the selection of the first target metal material is related to the material of the substrate.

[0028] According to an embodiment of the present disclosure, the thickness of the first photoresist layer is greater than the thickness of the Y-type gate, and the first electron beam photoresist is PMMA photoresist.

[0029] According to a second aspect of the present disclosure, a Y-type gate prepared by the above-mentioned Y-type gate preparation method is provided.

[0030] According to the preparation method of the Y-type grid and the Y-type grid prepared by the present invention, a first electron beam photoresist located on the upper surface of the substrate is subjected to deep ultraviolet light irradiation treatment to obtain a first photoresist layer, so that the molecular weight of the first electron beam photoresist is degraded by deep ultraviolet light irradiation treatment, and a second electron beam photoresist is spin-coated on the surface of the first photoresist layer to obtain a second photoresist layer, wherein the sensitivity of the second electron beam photoresist is higher than that of the first electron beam photoresist, and the preparation of the Y-type grid is realized by a double-layer glue process, thereby avoiding the mutual influence between the photoresists caused by the multi-layer glue process, and due to the first photoresist layer in the first photoresist layer after deep ultraviolet light irradiation treatment, the second electron beam photoresist is degraded by deep ultraviolet light irradiation treatment, and the second electron beam photoresist is degraded by deep ultraviolet light irradiation treatment. The degree of degradation of the molecular weight of an electron beam photoresist gradually decreases from top to bottom, and a first exposure and development operation is performed on a first photoresist layer and a second photoresist layer, so that a gate cap structure of a Y-type gate can be obtained. Then, a second exposure and development operation is performed on the first photoresist layer after the first exposure and development operation, so as to obtain a gate foot structure of the Y-type gate. Since the exposure and development operation is performed directly on the first photoresist layer after the first exposure and development operation, the thickness of the photoresist during the exposure of the gate foot is reduced, and a smaller gate foot can be prepared. Finally, a metal evaporation method is used to fill the target metal material into the gate cap structure and the gate foot structure, so as to obtain a Y-type gate. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above contents and other purposes, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0032] Figure 1 A flow chart schematically shows a method for preparing a Y-type gate according to an embodiment of the present disclosure;

[0033] Figure 2 A schematic diagram of performing deep ultraviolet light irradiation treatment on a first electron beam photoresist according to an embodiment of the present disclosure is schematically shown;

[0034] Figure 3 Schematically shows a schematic diagram of a substrate, a first photoresist layer, and a second photoresist layer according to an embodiment of the present disclosure;

[0035] Figure 4 A schematic diagram of a gate cap structure of a Y-type gate obtained after a first exposure and development operation according to an embodiment of the present disclosure is schematically shown;

[0036] Figure 5 A schematic diagram of a gate foot structure of a Y-type gate obtained after a second exposure and development operation according to an embodiment of the present disclosure is schematically shown;

[0037] Figure 6 Schematically shows a schematic diagram after metal evaporation according to an embodiment of the present disclosure;

[0038] Figure 7 A schematic diagram of a Y-type gate according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0039] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0040] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0041] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0042] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0043] In the technical solution of the present disclosure, the collection, storage, use, processing, transmission, provision, disclosure and application of the data involved (including but not limited to user personal information) comply with the provisions of relevant laws and regulations, take necessary confidentiality measures, and do not violate public order and good morals.

[0044] In the process of implementing the present disclosure, it is found that among the many factors that affect the performance of high electron mobility devices (HEMT, High Electron Mobility Transistor), the length and morphology of the gate are extremely important for improving the operating frequency of the device and suppressing noise. The Y-type gate has both a large cross-sectional area and a small gate foot size, and the distance between the gate cap and the source and drain is relatively large. Therefore, it can not only reduce the gate resistance, but also effectively reduce the parasitic capacitance between the gate and the source and drain, thereby contributing to the high-frequency characteristics of the device. At present, the deep submicron Y-type gate in the high electron mobility device is realized by electron beam exposure technology. The specific technical solutions include controlling the exposure method of the electron beam, utilizing the anisotropic corrosion characteristics of the crystal material, and using electron beam glues of different sensitivities. However, in the related art, there are problems such as fewer preparation schemes, high process requirements, extremely high requirements for electron beam glue, and great difficulty in preparation for the preparation of the Y-type gate.

[0045] To this end, an embodiment of the present disclosure provides a method for preparing a Y-type gate, comprising: performing deep ultraviolet light irradiation treatment on a first electron beam photoresist located on an upper surface of a substrate to obtain a first photoresist layer; spin-coating a second electron beam photoresist on the surface of the first photoresist layer to obtain a second photoresist layer, wherein the second electron beam photoresist has a higher sensitivity than the first electron beam photoresist; performing a first exposure and development operation on the first photoresist layer and the second photoresist layer to obtain a gate cap structure of the Y-type gate; performing a second exposure and development operation on the first photoresist layer after the first exposure and development operation to obtain a gate foot structure of the Y-type gate; and using a metal evaporation method to fill the target metal material into the gate cap structure and the gate foot structure to obtain a Y-type gate.

[0046] The following Figure 1 to Figure 7 The preparation method of the Y-type gate according to the embodiment of the present disclosure is described in detail.

[0047] Figure 1 The flowchart of the method for preparing the Y-type gate according to the embodiment of the present disclosure is schematically shown.

[0048] like Figure 1 As shown, the method 100 includes operations S110 to S150.

[0049] In operation S110, a first electron beam photoresist on an upper surface of the substrate is irradiated with deep ultraviolet light to obtain a first photoresist layer.

[0050] According to the embodiments of the present disclosure, the first electron beam photoresist may be spin-coated on the substrate surface and the first electron beam photoresist may be baked. For example, a hot plate may be used for baking, the baking temperature may be set to 180° C., and the baking time may be set to 2-3 minutes.

[0051] According to the embodiments of the present disclosure, the first electron beam photoresist can be subjected to deep ultraviolet light irradiation treatment, and the deep ultraviolet light has a certain photolysis effect on the first electron beam photoresist, which can degrade the macromolecules in the first electron beam photoresist into low molecules. For example, the light source power used for the deep ultraviolet light irradiation treatment can be set to 60W, and the irradiation time can be set to 1 hour; alternatively, the light source power used for the deep ultraviolet light irradiation treatment can also be set to between 40-70W, and the irradiation time can be set to between 0.5-2 hours according to the selection of the light source power.

[0052] In operation S120, a second electron beam photoresist is spin-coated on the surface of the first photoresist layer to obtain a second photoresist layer.

[0053] According to an embodiment of the present disclosure, a second electron beam photoresist can be spin-coated on the surface of the first photoresist after deep ultraviolet light irradiation, and the second electron beam photoresist can be baked. For example, a hot plate can be used for baking, the baking temperature can be set to 180° C., and the baking time can be set to 2 minutes.

[0054] According to the embodiments of the present disclosure, the sensitivity of the second electron beam photoresist needs to be higher than that of the first electron beam photoresist, that is, the second electron beam photoresist needs a smaller photosensitivity dose than the first electron beam photoresist, that is, the second electron beam photoresist needs a smaller electron beam dose and is more easily exposed by the electron beam, that is, fewer electron beams are needed to expose the second electron beam photoresist. Therefore, the first electron beam photoresist with low sensitivity is placed on the first layer to obtain the first photoresist layer; the second electron beam photoresist with high sensitivity is placed on the second layer to obtain the second photoresist layer.

[0055] In operation S130 , a first exposure and development operation is performed on the first photoresist layer and the second photoresist layer to obtain a gate cap structure of a Y-type gate.

[0056] According to an embodiment of the present disclosure, an electron beam lithography machine can be used to expose the first photoresist layer and the second photoresist layer according to a preset size of the second photoresist layer to be exposed and a preset exposure dose, and the exposed first photoresist layer and the second photoresist layer can be developed with a developer, fixed with a fixer, and blown dry to obtain a gate cap structure of a Y-type gate.

[0057] According to an embodiment of the present disclosure, the preset size of the second photoresist layer to be exposed can represent the size of the opening required in the second photoresist layer, wherein the opening of the second photoresist layer is only limited by a window, so that the first photoresist layer can be directly exposed and developed through the opening. The preset exposure dose can represent the number of preset electron beams.

[0058] In operation S140, a second exposure and development operation is performed on the first photoresist layer after the first exposure and development operation to obtain a gate foot structure of a Y-type gate.

[0059] According to the embodiments of the present disclosure, after the first exposure and development operation is performed, the first photoresist layer may be directly subjected to a second exposure and development operation through the opening of the second photoresist layer to obtain a gate foot structure of a Y-type gate.

[0060] According to the embodiments of the present disclosure, an electron beam lithography machine can be used to expose the first photoresist layer after the first exposure and development operation according to the preset gate foot size and the preset exposure dose, and the exposed second photoresist layer can be developed with a developer, fixed with a fixer, and blown dry to obtain a Y-type gate foot structure.

[0061] In operation S150 , a target metal material is filled into the gate cap structure and the gate foot structure by using a metal evaporation method to obtain a Y-type gate.

[0062] According to the embodiments of the present disclosure, a metal evaporation method can be used to fill the target metal material into the obtained gate cap structure and gate foot structure, thereby obtaining a Y-type gate. The obtained gate cap structure and gate foot structure are equivalent to the model of the Y-type gate to be prepared.

[0063] According to an embodiment of the present disclosure, a first electron beam photoresist located on the upper surface of a substrate is subjected to deep ultraviolet light irradiation treatment to obtain a first photoresist layer, so that the molecular weight of the first electron beam photoresist is degraded by deep ultraviolet light irradiation treatment, and a second electron beam photoresist is spin-coated on the surface of the first photoresist layer to obtain a second photoresist layer, wherein the sensitivity of the second electron beam photoresist is higher than that of the first electron beam photoresist, and a double-layer glue process is used to realize the preparation of a Y-type gate, thereby avoiding the mutual influence between photoresists caused by a multi-layer glue process, and due to the first electron beam photoresist in the first photoresist layer after deep ultraviolet light irradiation treatment The degree of molecular weight degradation gradually decreases from top to bottom, and the first photoresist layer and the second photoresist layer are subjected to a first exposure and development operation to obtain a gate cap structure of a Y-type gate. The first photoresist layer subjected to the first exposure and development operation is then subjected to a second exposure and development operation to obtain a gate foot structure of the Y-type gate. Since the exposure and development operation is directly performed on the first photoresist layer after the first exposure and development operation, the thickness of the photoresist during the exposure of the gate foot is reduced, and a smaller gate foot can be prepared. Finally, a metal evaporation method is used to fill the target metal material into the gate cap structure and the gate foot structure to obtain a Y-type gate.

[0064] According to an embodiment of the present disclosure, the thickness of the first photoresist layer is greater than the thickness of the Y-type gate, and the first electron beam photoresist is PMMA photoresist.

[0065] According to an embodiment of the present disclosure, the first electron beam photoresist may be PMMA (Poly Methyl Methacrylate) photoresist, for example, the first electron beam photoresist may be PMMA950 or PMMA495. Among them, PMMA photoresist has a longer molecular weight and is more resistant to degradation by deep ultraviolet light.

[0066] According to the embodiment of the present disclosure, the prepared Y-type gate is in the first photoresist layer, therefore, it is necessary to ensure that the thickness of the first photoresist layer is greater than the thickness of the Y-type gate to be prepared. The second photoresist layer is to obtain an opening so that the first photoresist layer can be directly exposed and developed for the second time, therefore, the thickness of the second photoresist layer can be appropriate. For example, the thickness of the first photoresist layer can be set to 550-650nm, and the thickness of the second photoresist layer can be set to 200-300nm.

[0067] According to an embodiment of the present disclosure, since the second electron beam photoresist has higher sensitivity than the first electron beam photoresist, the second electron beam photoresist may be selected to have higher sensitivity than PMMA photoresist. For example, the second electron beam photoresist may be selected to be ZEP520 photoresist.

[0068] According to an embodiment of the present disclosure, the thickness of the first photoresist layer is greater than the thickness of the Y-type grating, so that the prepared Y-type grating can be formed in the first photoresist layer. The first electron beam photoresist is PMMA photoresist, so that after the first electron beam photoresist is treated with deep ultraviolet light, the molecular weight in the first electron beam photoresist can be degraded to a certain extent, so as to facilitate subsequent exposure and development operations.

[0069] According to an embodiment of the present disclosure, a first electron beam photoresist located on an upper surface of a substrate is subjected to deep ultraviolet light irradiation treatment to obtain a first photoresist layer, including: utilizing deep ultraviolet light irradiation treatment to degrade the molecular weight of the first electron beam photoresist to obtain the first photoresist layer, wherein the degree of degradation of the molecular weight of the first electron beam photoresist in the first photoresist layer gradually decreases from top to bottom.

[0070] According to the embodiments of the present disclosure, the first photoresist layer has a certain thickness, and is irradiated with deep ultraviolet light because deep ultraviolet light has a photodegradation effect on the polymer in the first electron beam photoresist, thereby breaking the polymer chains in the first electron beam photoresist to obtain low molecular chains, that is, degrading the polymer into low molecular weight molecules.

[0071] According to the embodiments of the present disclosure, since the first photoresist layer has a certain thickness, the intensity of deep ultraviolet light irradiating the surface of the first photoresist layer will be stronger. As the depth increases, the light intensity received by the first electron beam photoresist in the first photoresist layer will be weaker, and the degree of damage to the polymer chain will be smaller, which ultimately makes the first electron beam photoresist closer to the surface of the first photoresist layer decompose more strongly, and the first electron beam photoresist in the lower layer decomposes more weakly. Therefore, in the case of the subsequent first exposure and development operation, since the degree of degradation of the molecular weight of the first electron beam photoresist in the first photoresist layer gradually decreases from top to bottom, the degree of development of the first electron beam photoresist in the first photoresist layer during development is also gradually reduced from top to bottom, so that the width of the structure in the first photoresist layer obtained after the first exposure and development operation is gradually reduced from top to bottom, that is, an inverted trapezoid can be formed, and a gate cap structure that conforms to the Y-type gate can be obtained.

[0072] According to the embodiments of the present disclosure, assuming that the first electron beam photoresist is not subjected to deep ultraviolet light irradiation treatment, when the first exposure and development operation is subsequently performed, no pattern will appear in the first photoresist layer, that is, it will not be developed. Since the deep ultraviolet light will reduce the molecular weight of the first electron beam photoresist, the first electron beam photoresist will be dissolved to a certain extent by the developer during development, and a corresponding pattern will be obtained. In the case where the polymer chain of the first electron beam photoresist is not completely destroyed, when the first exposure and development operation is performed, the developer has no effect on the first electron beam photoresist and will not dissolve the corresponding pattern; and after the first electron beam photoresist is subjected to deep ultraviolet light irradiation treatment, part of the polymer chains in the first electron beam photoresist are destroyed, and the developer will partially dissolve the first electron beam photoresist, and the closer to the surface of the first photoresist layer, the stronger the dissolution, and the lower the first electron beam photoresist, the weaker the dissolution, so an inverted trapezoidal structure with a wide top and a narrow bottom can be obtained.

[0073] According to the embodiments of the present disclosure, the molecular weight of the first electron beam photoresist is degraded by deep ultraviolet light irradiation treatment to obtain a first photoresist layer, so that during subsequent exposure and development operations, the developer will partially dissolve the first electron beam photoresist, and the closer the first electron beam photoresist is to the surface of the first photoresist layer, the stronger the dissolution, and the closer the first electron beam photoresist is to the bottom, the weaker the dissolution, thereby obtaining an inverted trapezoidal structure that is wide at the top and narrow at the bottom.

[0074] Figure 2 A schematic diagram of performing deep ultraviolet light irradiation treatment on a first electron beam photoresist according to an embodiment of the present disclosure is schematically shown.

[0075] like Figure 2 As shown, the first layer is a Substrate layer, and the second layer is a first electron beam photoresist spin-coated on the surface of the substrate, wherein the first electron beam photoresist can be a PMMA photoresist.

[0076] According to an embodiment of the present disclosure, a first electron beam photoresist located on the upper surface of the substrate is subjected to deep ultraviolet (DUV) irradiation treatment to obtain a first photoresist layer, that is, the above operation S110 is performed.

[0077] Figure 3 A schematic diagram of a substrate, a first photoresist layer and a second photoresist layer according to an embodiment of the present disclosure is schematically shown.

[0078] According to an embodiment of the present disclosure, the first photoresist layer on the substrate layer may be PMMA photoresist, and the second photoresist layer on the substrate layer may be ZEP photoresist.

[0079] According to the embodiments of the present disclosure, the sensitivity of the second photoresist layer needs to be higher than that of the first photoresist layer, that is, the first photoresist layer needs a larger electron beam dose than the second photoresist layer. If the first photoresist layer needs a smaller electron beam dose than the second photoresist layer, the first photoresist layer will be dissolved by the developer during the first exposure and development operation, and a gate cap structure will not be formed on the first photoresist layer, and there will be no second exposure and development operation.

[0080] According to an embodiment of the present disclosure, by performing the above operations S110 and S120, Figure 3 The substrate, the first photoresist layer and the second photoresist layer are shown.

[0081] According to an embodiment of the present disclosure, a first exposure and development operation is performed on the first photoresist layer and the second photoresist layer to obtain a gate cap structure of the Y-type gate, including: based on a first exposure size set for the second photoresist layer, an exposure operation is performed on the second photoresist layer to obtain a first exposure area of ​​the second photoresist layer; and a development operation is performed on the first exposure area to obtain a development structure of the second photoresist layer and a gate cap structure of the first photoresist layer.

[0082] According to an embodiment of the present disclosure, the photoresist in the exposed area can be dissolved by a developer; and the photoresist in the unexposed area cannot be dissolved by the developer.

[0083] According to an embodiment of the present disclosure, based on the first exposure size set for the second photoresist layer, the second photoresist layer is exposed to obtain a first exposure area of ​​the second photoresist layer. The first exposure size can characterize the size of the opening required in the second photoresist layer. For the second photoresist layer, which part is exposed by the electron beam, which part will only be developed using the developer. The first exposure area is developed, and a development structure portion corresponding to the first exposure area can be obtained in the second photoresist layer.

[0084] According to an embodiment of the present disclosure, the first exposure size is consistent with the required size of the opening of the second photoresist layer. For example, if the required size of the opening of the second photoresist layer is 30 nm×20 nm, the first exposure size can be set to 30 nm×20 nm.

[0085] According to the embodiments of the present disclosure, the developer also has a certain dissolving effect on the first electron beam photoresist irradiated with deep ultraviolet light. The stronger the intensity of the photoresist irradiated with deep ultraviolet light, the greater the degree of degradation of its molecular weight and the easier it is to be dissolved by the developer.

[0086] According to the embodiments of the present disclosure, during the process of deep ultraviolet light irradiation treatment of the first electron beam photoresist, as the depth of the first photoresist layer increases, the irradiation intensity of the deep ultraviolet light on the first electron beam photoresist in the first photoresist layer becomes weaker, and the developer dissolves the first electron beam photoresist closer to the surface of the first photoresist layer to a greater extent. At the same time, since the developer takes a longer time to dissolve the upper top layer of the first photoresist layer than the lower layer, the dissolved area will expand to both ends, so that the upper width of the inverted trapezoid formed is wider than the width of the opening of the second photoresist layer, thereby obtaining a Y-type gate cap structure.

[0087] According to the embodiments of the present disclosure, the exposed photoresist can be developed with a developer, fixed with a fixer, and then blown dry to obtain a gate cap structure of a Y-type gate. For example, the developer can be N50, the development time can be set to 3-4 minutes, the fixer can be isopropyl alcohol (IPA), the fixation time can be set to 30-60 seconds, and nitrogen is blown dry to obtain a development structure and a gate cap structure, wherein the selection of the developer and the fixer is related to the selection of the photoresist.

[0088] According to an embodiment of the present disclosure, based on the first exposure size set for the second photoresist layer, an exposure operation is performed on the second photoresist layer to obtain a first exposure area of ​​the second photoresist layer, and thus a development structure of the second photoresist layer and a gate cap structure of the first photoresist layer can be obtained by performing a development operation on the first exposure area.

[0089] Figure 4 A schematic diagram of a gate cap structure of a Y-type gate obtained after a first exposure and development operation according to an embodiment of the present disclosure is schematically shown.

[0090] like Figure 4 As shown, the structure obtained after development in the second photoresist layer (ZEP) is a developed structure, that is, an opening is obtained in the second photoresist layer. The structure obtained after development in the first photoresist layer (PMMA) is a gate cap structure of a Y-type gate.

[0091] According to the embodiments of the present disclosure, since the first photoresist layer has a certain thickness, the intensity of deep ultraviolet light irradiating the surface of the first photoresist layer will be stronger. As the depth increases, the light intensity received by the first electron beam photoresist in the first photoresist layer will be weaker, and the degree of damage to the polymer chain will be smaller, which ultimately makes the first electron beam photoresist closer to the surface of the first photoresist layer decompose more strongly, and the first electron beam photoresist in the lower layer decomposes more weakly. Therefore, in the case of the subsequent first exposure and development operation, since the degree of degradation of the molecular weight of the first electron beam photoresist in the first photoresist layer gradually decreases from top to bottom, the degree of development of the first electron beam photoresist in the first photoresist layer during development is also gradually reduced from top to bottom, so that the width of the structure in the first photoresist layer obtained after the first exposure and development operation is gradually reduced from top to bottom, that is, an inverted trapezoid can be formed, and a gate cap structure that conforms to the Y-type gate can be obtained.

[0092] According to an embodiment of the present disclosure, by performing the above operation S130, the following can be obtained: Figure 4 The development structure and gate cap structure shown.

[0093] According to an embodiment of the present disclosure, a development operation is performed on the first exposure area to obtain a development structure of the second photoresist layer and a gate cap structure of the first photoresist layer, including: using a first developer to perform a development operation on the first exposure area of ​​the second photoresist layer to obtain the development structure of the second photoresist layer; after obtaining the development structure, using the first developer to perform a development operation on the first photoresist layer based on the degree of degradation of the molecular weight of the first electron beam photoresist in the first photoresist layer to obtain a gate cap structure, wherein the gate cap structure is an inverted trapezoidal structure.

[0094] According to the embodiments of the present disclosure, since the exposed area of ​​the second photoresist layer will only be developed during the development process, the first exposed area of ​​the second photoresist layer can be developed using the first developer to obtain a development structure of the second photoresist layer.

[0095] According to the embodiments of the present disclosure, during the deep ultraviolet light irradiation treatment of the first electron beam photoresist, as the depth of the first photoresist layer increases, the irradiation intensity of the deep ultraviolet light on the first electron beam photoresist in the first photoresist layer becomes weaker, and the first developer dissolves the first electron beam photoresist closer to the surface of the first photoresist layer to a greater extent, thereby obtaining a gate cap structure of an inverted trapezoidal structure. For example, the first developer may be N50. The selection of the first developer is related to the selection of the photoresist.

[0096] According to the embodiments of the present disclosure, since the degree of degradation of the molecular weight of the first electron beam photoresist in the first photoresist layer gradually decreases from top to bottom, during the development operation, the developer dissolves the first electron beam photoresist closer to the surface of the first photoresist layer to a greater extent, thereby obtaining an inverted trapezoidal gate cap structure.

[0097] According to an embodiment of the present disclosure, a second exposure and development operation is performed on the first photoresist layer after the first exposure and development operation to obtain a gate foot structure of a Y-type gate, including: based on a second exposure size set for the first photoresist layer, an exposure operation is performed on the first photoresist layer after the first exposure and development operation to obtain a second exposure area of ​​the second photoresist layer; using a second developer, a development operation is performed on the second exposure area to obtain a gate foot structure.

[0098] According to an embodiment of the present disclosure, based on the second exposure size set for the first photoresist layer, the first photoresist layer after the first exposure and development operation can be exposed to obtain a second exposure area of ​​the second photoresist layer, and the second exposure area can be developed using a second developer, thereby obtaining a gate foot structure. The second exposure size is consistent with the size of the gate foot to be prepared. For example, if the size of the gate foot to be prepared is 30nm×20nm, the second exposure size can be set to 30nm×20nm.

[0099] According to the embodiments of the present disclosure, the first photoresist layer after exposure can be developed with a developer, fixed with a fixer, and then blown dry to obtain a gate foot structure of a Y-type gate. For example, the developer can be MIBK:IPA (1:3), the development time can be set to 40-60 seconds, the fixer can be isopropyl alcohol, the fixation time can be set to 30-60 seconds, and nitrogen can be blown dry to obtain a gate foot structure.

[0100] According to the embodiments of the present disclosure, since the exposure and development operations are directly performed on the first photoresist layer after the first exposure and development operations, the thickness of the photoresist during the gate foot exposure is reduced, thereby enabling the preparation of a smaller gate foot.

[0101] Figure 5 A schematic diagram of a gate foot structure of a Y-type gate obtained after a second exposure and development operation according to an embodiment of the present disclosure is schematically shown.

[0102] like Figure 5 As shown, the first photoresist layer after the first exposure and development operation can be directly subjected to a second exposure and development operation through the opening area (development structure portion) on the second photoresist layer to obtain a gate foot structure under the gate cap structure in the first photoresist layer.

[0103] According to the embodiments of the present disclosure, Figure 5The inverted trapezoidal structure in the first photoresist layer is the gate cap structure of the Y-type gate, and the rectangular area below is the gate foot structure of the Y-type gate. Figure 5 All developed structures in the first photoresist layer are complete Y-type gate structures.

[0104] According to an embodiment of the present disclosure, by performing the above operation S140, the following can be obtained: Figure 5 The complete Y-type gate structure is shown.

[0105] According to an embodiment of the present disclosure, the target metal material may include a first target metal material and a second target metal material, and the target metal material is filled into a gate cap structure and a gate foot structure by a metal evaporation method to obtain a Y-type gate, including: forming an adhesion layer composed of the first target metal material on the surface of a substrate located in the gate foot structure by a metal evaporation method; filling the second target metal material into the gate cap structure and the gate foot structure by a metal evaporation method to obtain a target structure, wherein the target structure may include a Y-type gate composed of the first target metal material and the second target metal material.

[0106] According to an embodiment of the present disclosure, a metal evaporation method can be used to first form an adhesion layer composed of a first target metal material on the surface of a substrate located in a gate foot structure, and then a second target metal material can be filled into the gate cap structure and the gate foot structure by the metal evaporation method to obtain a target structure.

[0107] According to an embodiment of the present disclosure, the obtained Y-type gate can be composed of a first target metal material and a second target metal material. The second target metal material can include at least one metal material, and each metal material can be filled into the gate cap structure and the gate foot structure in turn by a metal evaporation method according to requirements, thereby obtaining a Y-type gate.

[0108] According to the embodiments of the present disclosure, for example, Ti / Au metal evaporation can be performed on the obtained gate cap structure and gate foot structure to obtain a sample of evaporated metal, i.e., a target structure. The thickness of the metal Ti (titanium) can be set to 10 nm, and as an adhesion layer between the metal Au (gold) and the substrate, the thickness of Au can be set to 300 nm.

[0109] According to the embodiments of the present disclosure, the selection of the first target metal material is related to the material of the substrate, that is, it is related to the material on which the Y-type gate is prepared. The adhesion layer can make the Y-type gate adhere to the substrate more firmly, and will not fall off the substrate layer during the debonding process. During the debonding process, if there is no adhesion layer, the metal Y-type gate may fall off the substrate layer, and the bonding part between the gate foot structure of the Y-type gate and the substrate is relatively small, and it may fall off easily during the peeling process.

[0110] According to the embodiments of the present disclosure, a metal evaporation method may be used to fill a target metal material into a gate cap structure and a gate foot structure, thereby obtaining a Y-type gate.

[0111] According to an embodiment of the present disclosure, the selection of the first target metal material is related to the material of the substrate.

[0112] According to the embodiments of the present disclosure, the substrate material is not specific and can be selected from conventional materials such as silicon, silicon oxide, glass, quartz, diamond, silicon carbide, indium phosphide, gallium nitride, sapphire, etc. commonly used in semiconductor processes, and is also applicable to new two-dimensional materials such as graphene, carbon nanotubes, fullerenes or molybdenum disulfide. Similarly, the metal material of the prepared Y-type gate is not specific and can be selected from metal materials including gold, silver, copper, titanium, chromium, nickel, molybdenum, platinum, palladium, etc. The metal material of the Y-type gate can be a metal material selected according to the preparation requirements.

[0113] According to the embodiments of the present disclosure, the first target metal material for the adhesion layer is selected according to the substrate material, so that the Y-type gate can be more firmly adhered to the substrate and will not fall off the substrate layer during the debonding process.

[0114] Figure 6 The schematic diagram after metal evaporation according to an embodiment of the present disclosure is schematically shown.

[0115] like Figure 6 As shown, a Y-type grid with a preset thickness can be obtained by a metal evaporation method.

[0116] According to an embodiment of the present disclosure, Figure 6 All parts in the gate can constitute the target structure. When the metal is evaporated, metal will be evaporated on all surface planes, and the metal can be evaporated into the gate cap structure and the gate foot structure from the opening area of ​​the second photoresist layer, wherein the thickness of the metal layer on the second photoresist layer is consistent with the thickness of the Y-type gate.

[0117] According to the embodiments of the present disclosure, since the metal evaporation is not a straight line but may be curved, the shape of the upper surface of the Y-shaped gate can be any shape obtained by metal evaporation, for example, a straight line, a slant line, Figure 6 The groove shape shown in the figure can be used, as long as the edge portion of the gate cap structure and the gate foot structure in the first photoresist layer obtained after development is Y-shaped.

[0118] According to an embodiment of the present disclosure, by performing the above operation S150, the following can be obtained: Figure 6 The target structure in the photoresist layer and the Y-type gate in the first photoresist layer.

[0119] According to an embodiment of the present disclosure, the method for preparing the Y-type gate further includes: stripping off the first photoresist layer, the second photoresist layer and the metal layer on the second photoresist layer obtained by a metal evaporation method in the target structure to obtain the Y-type gate.

[0120] According to the embodiments of the present disclosure, the target structure can be stripped to remove the residual electron beam glue and the metal on its surface, that is, the first photoresist layer, the second photoresist layer and the metal layer on the second photoresist layer obtained by the metal evaporation method in the target structure are stripped, so that a Y-type gate can be obtained. The stripping is performed using an NMP solution, the stripping temperature can be set to 60°C, and the stripping time can be set to 1 hour. There is no adhesion between the metal on the upper surface of the second photoresist layer and the lower second photoresist layer, so it can be stripped off.

[0121] According to an embodiment of the present disclosure, the first photoresist layer, the second photoresist layer and the metal layer on the second photoresist layer obtained by a metal evaporation method in the target structure are stripped off to obtain a Y-type gate.

[0122] Figure 7 A schematic diagram of a Y-type gate according to an embodiment of the present disclosure is schematically shown.

[0123] like Figure 7 As shown, a Y-type gate structure on the substrate layer is obtained through the above operations S110 to S150.

[0124] According to an embodiment of the present disclosure, the Y-type gate may be formed of a variety of metal materials.

[0125] Of course, according to actual needs, the preparation method of the Y-type grid disclosed in the present invention also includes other processes and steps, which are irrelevant to the innovation of the present invention and will not be described here.

[0126] So far, the embodiments of the present disclosure have been described in detail in conjunction with the accompanying drawings. It should be noted that the implementation methods not shown or described in the drawings or the body of the specification are all forms known to ordinary technicians in the relevant technical field and are not described in detail. In addition, the above definitions of each element and method are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and ordinary technicians in the field can simply change or replace them.

[0127] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure.

[0128] In addition, unless the steps are specifically described or must occur in sequence, the order of the above steps is not limited to the above list, and can be changed or rearranged according to the required design. And the above embodiments can be mixed and matched with each other or with other embodiments based on design and reliability considerations, that is, the technical features in different embodiments can be freely combined to form more embodiments.

[0129] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A method for preparing a Y-type gate, comprising: Performing deep ultraviolet light irradiation treatment on the first electron beam photoresist located on the upper surface of the substrate to obtain a first photoresist layer; Spin coating a second electron beam photoresist on the surface of the first photoresist layer to obtain a second photoresist layer, wherein the second electron beam photoresist has a higher sensitivity than the first electron beam photoresist; Performing a first exposure and development operation on the first photoresist layer and the second photoresist layer to obtain a gate cap structure of a Y-type gate; Performing a second exposure and development operation on the first photoresist layer after the first exposure and development operation to obtain a gate foot structure of the Y-type gate; The target metal material is filled into the gate cap structure and the gate foot structure by using a metal evaporation method to obtain the Y-type gate.

2. The method according to claim 1, wherein: The method of subjecting the first electron beam photoresist located on the upper surface of the substrate to deep ultraviolet light irradiation to obtain a first photoresist layer comprises: The molecular weight of the first electron beam photoresist is degraded by the deep ultraviolet light irradiation treatment to obtain the first photoresist layer, wherein the degradation degree of the molecular weight of the first electron beam photoresist in the first photoresist layer gradually decreases from top to bottom.

3. The method according to claim 1, wherein: The first exposure and development operation is performed on the first photoresist layer and the second photoresist layer to obtain a gate cap structure of a Y-type gate, including: Based on a first exposure size set for the second photoresist layer, performing an exposure operation on the second photoresist layer to obtain a first exposure area of ​​the second photoresist layer; A development operation is performed on the first exposure area to obtain a development structure of the second photoresist layer and the gate cap structure of the first photoresist layer.

4. The method according to claim 2 or 3, wherein: The developing operation is performed on the first exposure area to obtain the developed structure of the second photoresist layer and the gate cap structure of the first photoresist layer, including: Using a first developer, developing the first exposed area of ​​the second photoresist layer to obtain the developed structure of the second photoresist layer; and After obtaining the development structure, the first photoresist layer is developed using the first developer based on the degree of degradation of the molecular weight of the first electron beam photoresist in the first photoresist layer to obtain the gate cap structure, wherein the gate cap structure is an inverted trapezoidal structure.

5. The method according to claim 1, wherein: The step of performing a second exposure and development operation on the first photoresist layer after the first exposure and development operation to obtain the gate foot structure of the Y-type gate comprises: Based on a second exposure size set for the first photoresist layer, performing an exposure operation on the first photoresist layer after the first exposure and development operation to obtain a second exposure area of ​​the second photoresist layer; The second exposure area is developed using a second developer to obtain the gate foot structure.

6. The method according to claim 1, wherein: The target metal material includes a first target metal material and a second target metal material. The target metal material is filled into the gate cap structure and the gate foot structure by a metal evaporation method to obtain the Y-type gate, including: Using a metal evaporation method, forming an adhesion layer composed of the first target metal material on the surface of the substrate located in the gate pin structure; The second target metal material is filled into the gate cap structure and the gate foot structure by using the metal evaporation method to obtain a target structure, wherein the target structure includes the Y-type gate composed of the first target metal material and the second target metal material.

7. The method according to claim 6, further comprising: The first photoresist layer, the second photoresist layer and the metal layer on the second photoresist layer obtained by the metal evaporation method in the target structure are peeled off to obtain the Y-type gate.

8. The method according to claim 6, wherein: The selection of the first target metal material is related to the material of the substrate.

9. The method according to claim 1, wherein: The thickness of the first photoresist layer is greater than the thickness of the Y-type gate, and the first electron beam photoresist is PMMA photoresist.

10. A Y-type gate prepared by the method according to any one of claims 1 to 9.

Images