CN117706863A - Photoresist mask and manufacturing method thereof, and manufacturing method of metal structure - Google Patents

Abstract

The invention discloses a photoresist mask, a manufacturing method thereof and a manufacturing method of a metal structure. The photoresist mask includes: a first photoresist layer formed on the substrate, the first photoresist layer having a first opening exposing the substrate; the metal layer is formed on the first photoresist layer, and a limiting opening with the width smaller than that of the first opening is formed in the area, corresponding to the first opening, of the metal layer; and a second photoresist layer formed on the metal layer, the second photoresist layer being formed with a second opening completely exposing the defined opening, wherein the first photoresist layer and the second photoresist layer are sensitive to different light rays. The invention can ensure that the width of the metal structure is not affected after the residual glue is removed.

Description

Photoresist mask and manufacturing method thereof, and manufacturing method of metal structure

Technical Field

The present invention relates to the field of integrated circuit manufacturing technology, and in particular, to a photoresist mask, a method for manufacturing the same, and a method for manufacturing a metal structure.

Background

The fabrication of integrated circuits is not separated from the photolithographic process, in which photoresist is usually used as a mask, then an opening of a specific shape is obtained through exposure and development, and then a metal material is deposited based on the opening to obtain the desired metal structure. In order to facilitate subsequent mask stripping, the mask is usually a double-layer photoresist, and an opening of an undercut structure is formed in the double-layer photoresist, the opening of the upper-layer photoresist determines the width of the metal structure, and the width of the opening of the lower-layer photoresist is larger than that of the upper-layer photoresist, so that the adhesion between the metal structure and the lower-layer photoresist is avoided.

Because the process precision of exposure is limited, after the photoresist is exposed and developed to obtain an opening, residual photoresist exists in the opening, and the residual photoresist is usually removed by adopting a plasma (plasma) etching mode in the prior art. However, the inventor of the application has found through long-term research that plasma etching belongs to non-directional etching, and not only can residual glue be removed, but also the side wall of the opening can be etched, so that the opening widths of the upper photoresist layer and the lower photoresist layer are enlarged, and the width of the metal structure is larger than an expected value. As shown in fig. 1, which is a schematic diagram comparing the opening widths of the masks before and after removing the residual photoresist in the prior art, fig. 1a shows that the opening width of the upper photoresist L1 is D and the opening width of the lower photoresist L2 is D before removing the residual photoresist, and fig. 1b shows that the opening width of the upper photoresist L1 is d+x and the opening width of the lower photoresist L2 is d+x after removing the residual photoresist, and the opening widths are respectively enlarged by X and X, and the opening width of the upper photoresist L1 determines the width of the metal structure, so that the width of the finally obtained metal structure becomes larger.

Disclosure of Invention

The invention aims to provide a photoresist mask, a manufacturing method thereof and a manufacturing method of a metal structure, which are used for solving the problem that the width of the metal structure is increased after residual glue is removed in the prior art, and ensuring that the width of the metal structure is not affected after the residual glue is removed.

In order to solve the above technical problems, the present invention provides a photoresist mask, comprising:

a first photoresist layer formed on a substrate, the first photoresist layer being formed with a first opening exposing the substrate;

a metal layer formed on the first photoresist layer, wherein a limited opening with a width smaller than that of the first opening is formed in a region of the metal layer corresponding to the first opening;

and a second photoresist layer formed on the metal layer, the second photoresist layer being formed with a second opening that completely exposes the defined opening, wherein the first photoresist layer and the second photoresist layer are sensitive to different light rays.

Preferably, the first opening, the defined opening and the second opening are bilaterally symmetrical along the same symmetry line.

Preferably, the width of the second opening is greater than the width of the defined opening.

Preferably, the material of the first photoresist layer is ultraviolet photoresist, and the material of the second photoresist layer is electron beam photoresist.

In order to solve the technical problem, the invention also provides a method for manufacturing the photoresist mask, which comprises the following steps:

sequentially forming a first photoresist layer, a metal layer and a second photoresist layer on a substrate, wherein the first photoresist layer and the second photoresist layer are sensitive to different light rays;

photoetching the second photoresist layer to form a second opening exposing the metal layer;

etching the exposed metal layer to form a limiting opening exposing the first photoresist layer;

photoetching the exposed first photoresist layer to form an initial opening exposing the substrate;

and performing plasma etching on the first photoresist layer through the initial opening to expand the initial opening into a first opening with a width larger than that of the limiting opening.

Preferably, the first opening, the defined opening and the second opening are bilaterally symmetrical along the same symmetry line.

Preferably, the first photoresist layer is sensitive to ultraviolet light and the second photoresist layer is sensitive to electron beams.

Preferably, the metal layer is etched by adopting an ICP dry etching process.

In order to solve the above technical problems, the present invention further provides a method for manufacturing a metal structure, including:

providing a photoresist mask according to any one of the preceding claims on a substrate, or forming a photoresist mask according to a method of manufacturing a photoresist mask according to any one of the preceding claims on the substrate;

and performing evaporation coating through the first opening, the limiting opening and the second opening to form a metal structure with the width consistent with the width of the limiting opening on the substrate.

Preferably, the evaporating plating through the first opening, the limiting opening and the second opening includes:

performing oblique evaporation coating along a first direction with a preset included angle with the second photoresist layer through the limiting opening;

and performing oblique evaporation coating along a second direction which is symmetrical to the first direction in the normal direction of the second photoresist layer through the limiting opening.

Different from the situation of the prior art, the photoresist mask provided by the invention is provided with the metal layer between the double photoresist layers, the first photoresist layer is provided with the first opening, the metal layer is provided with the limiting opening, the second photoresist layer is provided with the second opening which is completely exposed out of the limiting opening, the limiting opening is formed in the metal layer, the metal layer is not influenced by removing residual photoresist, therefore, the width of the limiting opening is always kept unchanged, the width of a desired metal structure can be obtained based on the limiting opening, and therefore, after the residual photoresist is removed, the width of the metal structure is not influenced.

The manufacturing method of the photoresist mask, the manufacturing method of the metal structure and the photoresist mask provided by the invention belong to the same invention conception, have the same technical effects and are not repeated here.

Drawings

FIG. 1 is a diagram showing the comparison of the widths of the openings of the masks before and after removing the residual photoresist in the prior art.

Fig. 2 is a schematic structural diagram of a photoresist mask according to a first embodiment of the present invention.

Fig. 3a to 3e are process diagrams of a method for manufacturing a photoresist mask according to a second embodiment of the present invention.

Fig. 4a to fig. 4c are process diagrams illustrating a method for manufacturing a metal structure according to a third embodiment of the present invention.

Detailed Description

Specific embodiments of the present invention will be described in more detail below with reference to the drawings. Advantages and features of the invention will become more apparent from the following description and claims. It should be noted that the drawings are in a very simplified form and are all to a non-precise scale, merely for convenience and clarity in aiding in the description of embodiments of the invention.

In the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", etc., are based on the directions or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

Referring to fig. 2, a first embodiment of the present invention provides a photoresist mask. The photoresist mask includes: a first photoresist layer 11 formed on the substrate 100, the first photoresist layer 11 being formed with a first opening K1 exposing the substrate 100; a metal layer 12 formed on the first photoresist layer 11, wherein a limited opening K2 with a width smaller than that of the first opening K1 is formed in a region of the metal layer 12 corresponding to the first opening K1; a second photoresist layer 13 formed on the metal layer 12, the second photoresist layer 13 being formed with a second opening K3 completely exposing the defined opening K2, wherein the first photoresist layer 11 and the second photoresist layer 13 are sensitive to different light rays.

The photoresist mask of the embodiment is provided with two photoresist layers, a metal layer is arranged between the two photoresist layers, a first opening is formed in the first photoresist layer, a limiting opening is formed in the metal layer, a second opening which is completely exposed out of the limiting opening is formed in the second photoresist layer, the limiting opening is formed in the metal layer, the metal layer cannot be influenced by removing residual photoresist, therefore, the width of the limiting opening is always kept unchanged, when a metal structure is formed by depositing metal materials, the limiting opening is a region through which deposited materials pass, and therefore, the width of the metal structure can be expected based on the limiting opening, and the width of the metal structure can be prevented from being influenced after the residual photoresist is removed.

In the present embodiment, the first opening K1, the defining opening K2, and the second opening K3 are bilaterally symmetrical along the same symmetry line. The vertical distances from the two side walls of the first opening K1 to the two side walls defining the opening K2 are equal, and the vertical distances from the two side walls defining the opening K2 to the two side walls of the first opening K1 are also equal. Further, the width of the second opening K3 may be greater than the width defining the opening K2.

Since the first photoresist layer 11 and the second photoresist layer 13 are sensitive to different light, the second photoresist layer 13 is not affected when the first photoresist layer 11 performs photolithography, and similarly, the first photoresist layer 11 is not affected when the second photoresist layer 13 performs photolithography, so that the formation of the first opening K1 and the second opening K3 can be facilitated. In this embodiment, the material of the first photoresist layer 11 is ultraviolet photoresist, and the material of the second photoresist layer 13 is electron beam photoresist. The metal layer 12 may be made of any metal material, for example, the first photoresist layer 11 is a photoresist with a model number SPR955, the thickness is about 500nm, the metal layer 12 is aluminum, the thickness is about 200nm, and the second photoresist layer 13 is a photoresist with a model number PMMA A4 495, the thickness is about 500nm.

Referring to fig. 3a to 3e, and in combination with fig. 2, a second embodiment of the present application provides a method for manufacturing a photoresist mask. The manufacturing method comprises the following steps:

s11: and sequentially forming a first photoresist layer, a metal layer and a second photoresist layer on the substrate, wherein the first photoresist layer and the second photoresist layer are sensitive to different light rays. Wherein, as shown in fig. 3a, the first photoresist layer, the metal layer and the second photoresist layer are schematically formed. A first photoresist layer 11, a metal layer 12, and a second photoresist layer 13 are formed on a substrate 100. Specifically, a photoresist may be coated on the substrate 100 by a spin coating process to form a first photoresist layer 11, then a thermal evaporation coating process is performed on the first photoresist layer 11 to form a metal layer 12, and finally a spin coating process is performed on the photoresist layer 12 to form a second photoresist layer 13.

S12: and photoetching the second photoresist layer to form a second opening exposing the metal layer. The second photoresist layer can be exposed through a photoetching plate and then developed to form a second opening. As shown in fig. 3b, after the second opening is formed, the unexposed portion of the second photoresist layer 13 is remained after exposure and development, and the exposed portion is dissolved in the developing solution, thereby forming a second opening K3. In this embodiment, the second photoresist layer 13 is sensitive to the electron beam and only electron beam exposure can be performed.

S13: etching the exposed metal layer to form a limited opening exposing the first photoresist layer. As shown in fig. 3c, which is a schematic view after forming the defining opening, the metal layer 12 in the second opening K3 is etched away to form the defining opening K2. The metal layer 12 may be etched by various etching processes, for example, when aluminum is used for the metal layer 12, ICP (inductively coupled plasma) dry etching process may be used. Since the width of the limiting opening K2 does not exceed the width of the second opening K3 at the maximum, the width of the limiting opening K2 is determined by the second opening K3, the accuracy of the second opening K3 is determined by the accuracy of the exposure process, and the higher the accuracy of the exposure process is, the closer the width of the limiting opening K2 is to the desired value, so in the present invention, the second photoresist layer 13 is exposed by using a high-accuracy electron beam exposure process.

S14: and photoetching the exposed first photoresist layer to form an initial opening exposing the substrate. As shown in fig. 3d, is a schematic view after the initial opening is formed. Since the first photoresist layer 11 and the second photoresist layer 13 are sensitive to different light, and only the defining opening K3 exposes the first photoresist layer 11, the exposure of the first photoresist layer 11 within the defining opening K3 does not affect the second photoresist layer 13. After the exposure and development of the first photoresist layer 11, the unexposed portions remain, and the exposed portions are dissolved in a developing solution, thereby forming the initial opening K4. In this embodiment, the first photoresist layer 11 is sensitive to ultraviolet light and can be exposed only to ultraviolet light.

S15: and performing plasma etching on the first photoresist layer through the initial opening to expand the initial opening into a first opening with a width larger than that of the limiting opening. As shown in fig. 3e, a schematic view is provided after the first opening is formed. The plasma etching is non-directional etching, can etch photoresist, and hardly etches materials such as metal, substrate and the like. Since the two side walls of the initial opening K4 expose the first photoresist layer 11, the first photoresist layer 11 is etched laterally, so that the width of the initial opening K4 is widened, and finally the width of the initial opening K4 is widened to be larger than the width of the first opening K1 defining the opening K2, and meanwhile, the residual photoresist in the first opening K1, the first opening defining the opening K2 and the second opening K3 is removed by plasma etching. The first opening K1 and the defining opening K2 together form an undercut opening (undercut). Similarly, the width of the second opening K3 is also enlarged, and the second photoresist layer 13 is also thinned, but the width of the limiting opening K2 is not changed all the time, so that the change in the width of the second opening K3 does not affect.

In the present embodiment, the first opening K1, the defining opening K2, and the second opening K3 are bilaterally symmetrical along the same symmetry line. The vertical distances from the two side walls of the first opening K1 to the two side walls defining the opening K2 are equal, and the vertical distances from the two side walls defining the opening K2 to the two side walls of the first opening K1 are also equal. Further, the width of the second opening K3 may be greater than the width defining the opening K2.

Referring to fig. 4a to 4c, and in combination with fig. 2 and 3, a third embodiment of the present application provides a method for manufacturing a metal structure. The manufacturing method comprises the following steps:

s21: the photoresist mask of the foregoing embodiment is provided on a substrate, or the photoresist mask is formed on the substrate according to the manufacturing method of the photoresist mask of the foregoing embodiment. Taking the photoresist mask shown in fig. 2 or the photoresist mask formed according to the foregoing second embodiment as an example, as shown in fig. 4a, a schematic diagram is shown after the photoresist mask is formed, and the photoresist mask is formed on the substrate 100.

S22: and performing evaporation coating through the first opening, the limiting opening and the second opening to form a metal structure with the width consistent with the width of the limiting opening on the substrate. Wherein, as shown in fig. 4b, the metal structure is schematically formed. The first opening K1, the defining opening K2 and the second opening K3 expose the substrate 100, and the width of the defining opening K2 is the smallest, and during evaporation coating, the evaporation material can only be deposited on the substrate 100 through the defining opening K2, so that the metal structure 200 is finally formed, and the width of the metal structure 200 is consistent with the width of the defining opening K2.

In this embodiment, after the metal structure 200 is formed, the first photoresist layer 11 may be removed by a lift-off process, and then the metal layer 12 and the second photoresist layer 13 may be removed together with the first photoresist layer 11. Since the first opening K1 and the defining opening K2 constitute an undercut opening, the metal structure 200 does not adhere to the first photoresist layer 11, so that the first photoresist layer 11 can be directly peeled off without damaging the metal structure 200.

In some embodiments of the present application, the metal structure may be formed using a variety of evaporation coating processes, such as direct evaporation or oblique evaporation. Taking oblique evaporation as an example, the evaporation coating is performed through the first opening, the limiting opening and the second opening, that is, the step S22 specifically includes:

s221: and performing oblique evaporation coating along a first direction which forms a preset included angle with the second photoresist layer by limiting the opening. As shown in fig. 4b, the first direction a forms a predetermined angle with the second photoresist layer 13, the predetermined angle can be adjusted according to actual needs, and the evaporation material moves along the first direction a, and is finally deposited on the substrate 100.

S222: and performing oblique evaporation coating along a second direction symmetrical to the first direction in the normal direction of the second photoresist layer by limiting the opening. As shown in fig. 4B, the second direction B forms a predetermined angle with the second photoresist layer 13, but is symmetrical to the first direction a in the normal direction of the second photoresist layer 13, and the evaporated material moves along the second direction B, and is finally deposited on the substrate 100. The two oblique evaporation coatings can ensure the integrity and flatness of the metal structure 200.

The method of manufacturing the metal structure of the present embodiment can be applied to a superconducting quantum chip, for example, a josephson junction, the key structure of which is a superconducting wire, is manufactured using the method of manufacturing.

In the description of the present specification, a description of the terms "one embodiment," "some embodiments," "examples," or "particular examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments. Further, one skilled in the art can engage and combine the different embodiments or examples described in this specification.

The foregoing is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art will make any equivalent substitution or modification to the technical solution and technical content disclosed in the invention without departing from the scope of the technical solution of the invention, and the technical solution of the invention is not departing from the scope of the invention.

Claims (10)

1. A photoresist mask, comprising:

a first photoresist layer formed on a substrate, the first photoresist layer being formed with a first opening exposing the substrate;

a metal layer formed on the first photoresist layer, wherein a limited opening with a width smaller than that of the first opening is formed in a region of the metal layer corresponding to the first opening;

and a second photoresist layer formed on the metal layer, the second photoresist layer being formed with a second opening that completely exposes the defined opening, wherein the first photoresist layer and the second photoresist layer are sensitive to different light rays.

2. The photoresist mask of claim 1, wherein the first opening, the defined opening, and the second opening are bilaterally symmetric along the same line of symmetry.

3. The photoresist mask of claim 2, wherein a width of the second opening is greater than a width of the defined opening.

4. The photoresist mask of claim 1, wherein the material of the first photoresist layer is an ultraviolet photoresist and the material of the second photoresist layer is an electron beam photoresist.

5. A method of manufacturing a photoresist mask, comprising:

sequentially forming a first photoresist layer, a metal layer and a second photoresist layer on a substrate, wherein the first photoresist layer and the second photoresist layer are sensitive to different light rays;

photoetching the second photoresist layer to form a second opening exposing the metal layer;

etching the exposed metal layer to form a limiting opening exposing the first photoresist layer;

photoetching the exposed first photoresist layer to form an initial opening exposing the substrate;

and performing plasma etching on the first photoresist layer through the initial opening to expand the initial opening into a first opening with a width larger than that of the limiting opening.

6. The method of manufacturing of claim 5, wherein the first opening, the defined opening, and the second opening are bilaterally symmetric along the same line of symmetry.

7. The method of manufacturing according to claim 5, wherein the first photoresist layer is sensitive to ultraviolet light and the second photoresist layer is sensitive to electron beams.

8. The method of claim 5, wherein the metal layer is etched using an ICP dry etching process.

9. A method of manufacturing a metal structure, comprising:

providing a photoresist mask according to any one of claims 1 to 4 on a substrate, or forming a photoresist mask on the substrate according to the method of manufacturing a photoresist mask according to any one of claims 5 to 9;

and performing evaporation coating through the first opening, the limiting opening and the second opening to form a metal structure with the width consistent with the width of the limiting opening on the substrate.

10. The method of manufacturing according to claim 9, wherein the evaporation plating through the first opening, the defined opening, and the second opening comprises:

performing oblique evaporation coating along a first direction with a preset included angle with the second photoresist layer through the limiting opening;

and performing oblique evaporation coating along a second direction which is symmetrical to the first direction in the normal direction of the second photoresist layer through the limiting opening.