Method for stripping material

Abstract

The invention provides a method for stripping a material. The method comprises the following steps: forming a photoresist pattern on the surface of a substrate; forming a predetermined material layer on the surface of the substrate exposed from the photoresist pattern and the surface of the photoresist pattern; heating the substrate to a preset temperature, and applying a viscous film on the surface of the preset material layer; and the thin film is removed, and the part, located on the surface of the photoresist pattern, of the preset material layer is removed along with the thin film. According to the present application, it is possible to reliably peel off a material using a simple method.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and particularly to a method for stripping materials. Background Art

[0002] The lift-off process is to obtain a patterned photoresist structure or a mask such as metal (shadow mask) on a substrate by photolithography. A target coating is deposited on the photoresist structure or the mask by a coating process, and then the photoresist is dissolved by a stripping solution (also known as a lift-off solution) or the mask such as metal is removed mechanically, so as to obtain a target graphic structure consistent with the pattern on the substrate surface.

[0003] In the lift-off process using photoresist, usually each type of photoresist has a corresponding stripping solution. Under normal processes, using the supporting stripping solution can well implement the lift-off process. In addition, the lift-off process usually uses ultrasonic assistance, and part of the stripping solution is heated to 50 - 80 °C to accelerate the stripping process. Among them, heating some organic solvents is dangerous and requires correct and careful operation. In the lift-off process, the method of dry etching is preferably not used to remove the photoresist, because the small graphic openings on the photoresist will hinder the ashing of the photoresist, making it difficult to achieve the effect of removing the glue. In addition, the oxygen plasma used in dry stripping may oxidize the target coating made of metal.

[0004] It should be noted that the above introduction to the technical background is only for the convenience of clearly and completely explaining the technical solutions of this application and facilitating the understanding of those skilled in the art. It cannot be considered that the above technical solutions are well-known to those skilled in the art just because these solutions are described in the background art part of this application. Summary of the Invention

[0005] The inventors of this application found that the existing stripping technologies have certain limitations. For example, in the manufacturing of microelectromechanical systems (MEMS), some devices of the microelectromechanical systems cannot accept the ultrasonic process. In addition, the conventional lift-off process is complex and has certain risks, and the service life of the stripping solution is short, etc. Another example is that when using a mask such as metal for the lift-off process, the cost is extremely high, the alignment difficulty is large, and mass production is not possible.

[0006] An embodiment of this application provides a method for stripping materials. In this method, a sticky film is used to paste the surface of the material layer, and the sticky film is removed under heating conditions, which can take away the materials on the surface of the photoresist, thereby realizing the lift-off process. Thus, the materials can be reliably stripped by a simple method.

[0007] According to one aspect of the embodiments of this application, a method for stripping materials is provided, and the method includes:

[0008] A photoresist pattern is formed on the surface of the substrate;

[0009] A predetermined material layer is formed on the surface of the substrate exposed from the photoresist pattern and on the surface of the photoresist pattern;

[0010] The substrate is heated to a predetermined temperature, and a sticky film is applied to the surface of the predetermined material layer; and

[0011] The film is removed, wherein the portion of the predetermined material layer located on the surface of the photoresist pattern is removed together with the film.

[0012] In at least one embodiment, when the substrate is heated to the predetermined temperature, the photoresist pattern softens, so that the adhesion force between the photoresist pattern and the surface of the substrate is less than the adhesion force between the surface of the predetermined material layer and the film.

[0013] In at least one embodiment, in the step of heating the substrate to the predetermined temperature, the chuck for supporting the substrate is heated to 60°C to 130°C.

[0014] In at least one embodiment, the film is at least one of a blue film, an ultraviolet (UV) film, a back grinding film / tape, a dicing film / tape, a packaging film, a chip attachment film, and a polyimide film.

[0015] In at least one embodiment, the thickness of the predetermined material layer is 100 angstroms to 5000 angstroms

[0016] In at least one embodiment, the method further includes:

[0017] Removing the photoresist remaining on the surface of the substrate by a wet photoresist removal process or a dry photoresist removal process.

[0018] The beneficial effect of the present application is that by using a sticky film to stick to the surface of the material layer and removing the sticky film under heating conditions, the material on the surface of the photoresist can be taken away, thereby realizing a peeling process. Thus, the material can be reliably peeled by a simple method.

[0019] Referring to the following description and the accompanying drawings, specific embodiments of the present application are disclosed in detail, indicating the ways in which the principles of the present application can be adopted. It should be understood that the embodiments of the present application are not limited in scope thereby. Within the spirit and terms of the appended claims, the embodiments of the present application include many changes, modifications, and equivalents.

[0020] Features described and / or illustrated for one embodiment can be used in the same or similar way in one or more other embodiments, combined with features in the other embodiments, or instead of features in the other embodiments.

[0021] It should be emphasized that the term "comprising / including" as used herein refers to the presence of features, whole things, steps or components, but does not exclude the presence or addition of one or more other features, whole things, steps or components. Brief Description of the Drawings

[0022] The accompanying drawings included are used to provide a further understanding of the embodiments of the present application, which form a part of the specification, and are used to illustrate the embodiments of the present application and, together with the written description, to explain the principles of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts. In the drawings:

[0023] Figure 1 is a schematic diagram of a method for peeling a material according to an embodiment of the present application;

[0024] Figures 2 to 5 is a schematic diagram of the steps of an example of the present application. Detailed Embodiments

[0025] Referring to the accompanying drawings, through the following description, the foregoing and other features of the present application will become apparent. In the description and drawings, specific embodiments of the present application are specifically disclosed, which show some embodiments in which the principles of the present application can be adopted. It should be understood that the present application is not limited to the described embodiments. On the contrary, the present application includes all modifications, variations and equivalents falling within the scope of the appended claims.

[0026] In the description of the embodiments of the present application, for convenience of description, the direction parallel to the surface of the substrate is referred to as "lateral", and the direction perpendicular to the surface of the substrate is referred to as "longitudinal".

[0027] Embodiments

[0028] An embodiment of the present application provides a method for peeling a material.

[0029] Figure 1 is a schematic diagram of a method for peeling a material according to an embodiment of the present application. As Figure 1 shown, the method for peeling the material includes:

[0030] Operation 101, forming a photoresist pattern on the surface of the substrate;

[0031] Operation 102: Form a predetermined material layer on the surface of the substrate exposed from the photoresist pattern and on the surface of the photoresist pattern;

[0032] Operation 103: Heat the substrate to a predetermined temperature and apply a sticky film on the surface of the predetermined material layer; and

[0033] Operation 104: Remove the film, wherein the portion of the predetermined material layer located on the surface of the photoresist pattern is removed together with the film.

[0034] According to the embodiments of the present application, by pasting the surface of the material layer with a sticky film and removing the sticky film under heating conditions, the material on the surface of the photoresist can be taken away, thereby realizing the stripping process. Thus, the material can be reliably stripped by a simple method.

[0035] In the present application, the substrate can be a wafer commonly used in the semiconductor field, for example, a silicon wafer, a silicon-on-insulator (SOI) wafer, a silicon-germanium wafer, a sapphire substrate, a glass substrate, etc. The surface of the substrate can be a polished surface, or microelectronic components and / or microelectromechanical system (MEMS) components, etc. can be provided on the surface of the substrate.

[0036] In Operation 101, a photoresist can be coated on the surface of the substrate. The photoresist can be a positive photoresist or a negative photoresist. Then, through processes such as exposure and development, the unnecessary photoresist is removed to form a photoresist pattern. Among them, the surface of the substrate is exposed at the portion where the photoresist is removed.

[0037] In Operation 102, a predetermined material layer is formed on the surface of the photoresist pattern. The thickness of the predetermined material layer is, for example, 100 angstroms to 5000 angstroms The predetermined material layer can be a metal layer, for example, CrAu (chromium gold), TiPt (titanium platinum), Al (aluminum), AlCu (aluminum copper), TiAu (titanium gold), etc. In addition, the predetermined material layer can also be a non-metal layer. The predetermined material layer can be a single-layer material layer or a composite material layer.

[0038] In Operation 102, the method for forming the predetermined material layer can be methods such as evaporation and sputtering. In addition, in some embodiments, before forming the predetermined material layer, plasma pretreatment, etc. can be performed on the surface of the substrate and the surface of the photoresist pattern.

[0039] Through Operation 102, the predetermined material layer can be formed on the surface of the substrate exposed from the photoresist pattern and on the surface of the photoresist pattern.

[0040] In operation 103, heating the substrate to a predetermined temperature and applying a sticky film on the surface of a predetermined material layer can be performed simultaneously or sequentially. For example, the substrate can be heated to the predetermined temperature first, and then a sticky film is applied on the surface of the predetermined material layer; alternatively, the order of the above two operations can be reversed.

[0041] In the step of heating the substrate to the predetermined temperature, the chuck for supporting the substrate can be heated to 60°C to 130°C. For example, the chuck is heated to 70°C to 100°C. Thus, the chuck transfers heat to the substrate, causing the substrate to be heated to the predetermined temperature.

[0042] In operation 103, when the substrate is heated to the predetermined temperature, the photoresist pattern on the surface of the substrate softens, resulting in a decrease in the adhesion force between the photoresist pattern and the substrate. For example, the adhesion force between the photoresist pattern and the surface of the substrate is less than the adhesion force between the surface of the predetermined material layer and the sticky film.

[0043] In the present application, the sticky film can be a film used for wafer dicing, substrate dicing, wafer thinning, or encapsulation in semiconductor processes. For example, at least one of a blue film, an ultraviolet (UV) film, a back grinding film / tape, a dicing film / tape, an encapsulation film, a die attach film (DAF), and a polyimide film, etc. In addition, the sticky film can be a single-layer film or a multi-layer film.

[0044] In operation 104, when the substrate is heated to the predetermined temperature, the sticky film can be removed. For example, the sticky film is torn off. Thus, during the process of removing the sticky film, a part of the predetermined material layer located on the surface of the photoresist pattern can be taken away, thereby realizing the peeling of the predetermined material layer. In addition, other parts of the predetermined material layer are in direct contact with the surface of the substrate and firmly cover the surface of the substrate. Therefore, the part of the predetermined material layer in direct contact with the surface of the substrate is retained on the surface of the substrate and will not be removed along with the sticky film.

[0045] As Figure 1 shown, the method further includes the following operations:

[0046] Operation 105: Removing the photoresist remaining on the surface of the substrate by a wet stripping process or a dry stripping process.

[0047] For example, after operation 104, if there is photoresist remaining on the surface of the substrate, the photoresist remaining on the surface of the substrate can be removed by operation 105 using a wet stripping process. In addition, in operation 105, if the predetermined material layer remaining on the surface of the substrate is an inert metal, a dry stripping process can also be used to remove the remaining photoresist. For the descriptions of the wet stripping process and the dry stripping process, reference can be made to the related technologies.

[0048] Next, a specific example will be used to illustrate the method for stripping materials of the present application. Figures 2 to 5 It is a schematic diagram of each step of this example. The method of this example includes:

[0049] Step 1: As Figure 2 shown, a photoresist pattern 30 is formed on the surface of the substrate 20. Here, the type of photoresist can be positive photoresist or negative photoresist.

[0050] Step 2: As Figure 3 shown, vapor deposition or sputtering of a predetermined material layer 40 is performed using a vapor deposition device. The predetermined material layer can be a metal, and the type of the metal is not limited, nor is the thickness. For example, the metal is at least one of materials such as Al, AlCu, TiAu, CrAu, or TiPt, and the thickness is from 100 angstroms to 5000 angstroms

[0051] Step 3: As Figure 4 shown, the substrate 20 is moved to a blue film laminating device (for example, a manual blue film laminating machine), the heating chuck of the blue film laminating device is heated to a certain temperature (for example, the temperature is from 60°C to 130°C, preferably, the temperature is from 70°C to 100°C), and an automatic laminating operation is performed, that is, the sticky side of the blue film 50 (i.e., a sticky film) is attached to the surface of the predetermined material layer 40.

[0052] Step 4: As Figure 5 shown, the blue film 50 is torn off on the blue film laminating device by a manual film tearing method, so that the photoresist pattern 30 together with the predetermined material layer 40 (for example, metal) on its surface is peeled off, and the predetermined material layer 40 in direct contact with the surface of the substrate 20 remains on the surface of the substrate 20.

[0053] Step 5: The stripped substrate 20 is subjected to wet stripping or dry stripping to complete the patterning step of the predetermined material layer 40.

[0054] According to the present application, by pasting the surface of a material layer with a sticky thin film and removing the sticky thin film under heating conditions, the material on the surface of the photoresist can be carried away, thereby realizing a stripping process. Thus, the material can be reliably stripped by a simple method. In addition, this method does not require ultrasonic treatment. Therefore, it is particularly suitable for the manufacture of certain microelectromechanical systems (MEMS) that cannot accept ultrasonic treatment.

[0055] The present application has been described in conjunction with specific embodiments, but those skilled in the art should understand that these descriptions are exemplary and not a limitation on the scope of protection of the present application. Those skilled in the art can make various variations and modifications to the present application according to the spirit and principle of the present application, and these variations and modifications are also within the scope of the present application.

Claims

1. A method for stripping a material, characterized in that, the method comprises: forming a photoresist pattern on the surface of a substrate; forming a predetermined material layer on the surface of the substrate exposed from the photoresist pattern and on the surface of the photoresist pattern; heating the substrate to a predetermined temperature and applying a sticky film on the surface of the predetermined material layer; and removing the film, wherein the portion of the predetermined material layer located on the surface of the photoresist pattern is removed together with the film.

2. The method for stripping a material according to claim 1, wherein, when the substrate is heated to the predetermined temperature, the photoresist pattern softens, so that the adhesion force between the photoresist pattern and the surface of the substrate is less than the adhesion force between the surface of the predetermined material layer and the film.

3. The method for stripping a material according to claim 2, wherein, in the step of heating the substrate to the predetermined temperature, the chuck for supporting the substrate is heated to 60°C to 130°C.

4. The method for stripping a material according to claim 1, wherein, the film is at least one of a blue film, an ultraviolet (UV) film, a back grinding film / tape, a dicing film / tape, a packaging film, a chip attachment film, and a polyimide film.

5. The method for stripping a material according to claim 1, wherein, The thickness of the predetermined material layer is 100 angstroms to 5000 angstroms 6. The method for stripping a material according to claim 1, wherein, the method further comprises: removing the photoresist remaining on the surface of the substrate by a wet photoresist stripping process or a dry photoresist stripping process.

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