Manufacturing method of flexible product

Abstract

The invention provides a manufacturing method of a flexible product, which comprises the following steps: a first film layer is formed on a substrate, a second film layer is formed on the first film layer, and the surface binding force between the first film layer and the second film layer is smaller than the surface binding force between the first film layer and the substrate; and then the second film layer is separated from the first film layer in a mechanical separation mode according to the difference of binding force between different film layers, and the flexible product comprising the second film layer is obtained. According to the invention, the aim of mechanically separating the film layer from the substrate is fulfilled by utilizing the binding force difference between different film layers and manufacturing a film layer interface with low binding force, so that the danger caused by a chemical mode of corroding and releasing a sacrificial layer through a high-risk chemical drug and the limiting influence of some materials are avoided; and compared with a mode of directly and physically tearing the film from the substrate for separation, the method provided by the invention needs smaller separation force, so that the film layer deformation caused by mechanical separation is smaller, and meanwhile, the thinner film layer can be separated without film layer breakage caused by tearing.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor processing, and in particular relates to a method for manufacturing a flexible product. Background Art

[0002] There are two main methods for separating the polyimide (PI) film layer from the substrate: chemical and physical. The chemical method usually adds a sacrificial layer, such as a silicon oxide layer, between the PI film layer and the substrate, and releases the PI film layer by corroding the silicon oxide with hydrofluoric acid. The physical method separates the PI film layer from the substrate by purely mechanical film tearing.

[0003] However, for some specific application areas, chemical methods cannot be accepted because they require the use of chemicals, especially strong acids such as hydrofluoric acid and highly dangerous chemicals. The physical method of pure mechanical film tearing is usually only applicable to a small area and thicker film layer, and it is difficult to achieve large-area separation of thin PI film layers with a thickness of less than 2um, such as achieving PI film separation on an 8-inch wafer. Summary of the invention

[0004] The purpose of the present invention is to provide a method for manufacturing a flexible product, which can at least solve some of the defects in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A method for manufacturing a flexible product, comprising the following steps:

[0007] forming a first film layer on a substrate, and then forming a second film layer on the first film layer, wherein the surface bonding force between the first film layer and the second film layer is smaller than the surface bonding force between the first film layer and the substrate;

[0008] The second film layer is separated from the first film layer by mechanical separation to obtain a flexible product including the second film layer.

[0009] Furthermore, the mechanical separation method is: applying a force from one side of the second film layer to cause the substrate to crack and bend and warp, thereby achieving interface separation between the second film layer and the first film layer.

[0010] Furthermore, a notch is etched on the first film layer, and the splitting is performed starting from the side of the substrate facing away from the first film layer, and the splitting position of the substrate corresponds to the notch.

[0011] Furthermore, the mechanical separation method is: grooves are made on the surface of the second film layer by dry etching or laser cutting, the groove depth is not less than the thickness of the second film layer, and then the second film layer is peeled off at the corners to achieve interface separation between the second film layer and the first film layer;

[0012] Alternatively, the second film layer, the first film layer and the substrate are cut by a hard knife to obtain cut pieces, and then the second film layer on the cut pieces is peeled off to achieve interface separation between the second film layer and the first film layer.

[0013] Furthermore, the second film layer is a polyimide film, the first film layer is a polyimide film, and both the first film layer and the second film layer are formed by a spin coating and curing process.

[0014] Furthermore, after forming the second film layer on the first film layer, a transfer film is processed on the surface of the second film layer, and after the second film layer is separated from the first film layer, the transfer film is removed.

[0015] Furthermore, the transfer film is a UV film.

[0016] Furthermore, after forming the second film layer on the first film layer, a protective glue is sprayed on the surface of the second film layer.

[0017] Furthermore, the second film layer is a flexible film with a thickness less than 2 um.

[0018] Furthermore, after the second film layer is formed on the first film layer and before mechanical separation, a device layer is prepared on the second film layer, and after the second film layer is separated from the first film layer, a flexible device based on the second film layer is obtained.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The manufacturing method of the flexible product provided by the present invention utilizes the difference in bonding force between different film layers and achieves the purpose of mechanically separating the film layer from the substrate by manufacturing a film layer interface with low bonding force, thereby effectively avoiding the dangers brought by the chemical method of releasing the sacrificial layer through corrosion by highly dangerous chemicals and the limiting effects of certain materials; and compared with the method of directly physically tearing the film from the substrate, the separation force required by the present invention is smaller, so the deformation of the film layer caused by mechanical separation will also be smaller, and at the same time, thinner film layers can also be separated without causing the film layer to break due to tearing.

[0021] (2) The present invention can obtain a flexible device product based on a film layer by completing the preparation of a device layer on the film layer and then separating the film layer from the substrate. The manufacturing method is simple and greatly improves the quality of the flexible device product.

[0022] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the process flow of the PI film preparation method in Example 1 of the present invention;

[0024] Figure 2Schematic diagram of the process flow of the PI film preparation method in Example 2 of the present invention;

[0025] Figure 3 Schematic diagram of the process flow of the PI film preparation method in Example 3 of the present invention;

[0026] Figure 4 It is a schematic diagram of the process flow of the method for preparing a film-based flexible device product in Example 4 of the present invention.

[0027] Explanation of the reference numerals: 1. substrate; 2. first film layer; 3. second film layer; 4. notch; 5. transfer film; 6. split position; 7. device layer. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, a conflicting connection or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0032] Embodiment 1:

[0033] like Figure 1As shown, this embodiment provides a method for manufacturing a flexible product, specifically taking the preparation of a PI film as an example, comprising the following steps:

[0034] S1. Forming a first film layer 2 on a substrate 1.

[0035] Specifically, the substrate 1 may be selected from but not limited to common semiconductor wafers such as silicon wafers and glass wafers. The selection of the material of the first film layer 2 needs to make the surface bonding force between the first film layer 2 and the second film layer 3 (i.e., PI film) smaller than the surface bonding force between the first film layer 2 and the substrate 1. For example, the material of the first film layer 2 may be PI (polyimide), so that the surface bonding force between PI and PI is lower than the bonding force between PI and surfaces such as silicon or silicon oxide (i.e., glass).

[0036] Optimally, the first film layer 2 may be etched to form a groove 4, so as to facilitate the subsequent mechanical separation of the first film layer 2 and the second film layer 3.

[0037] S2. Forming a second film layer 3 on the first film layer 2. In this embodiment, the second film layer is the PI film to be prepared.

[0038] Specifically, in this embodiment, the preparation of the first film layer 2 and the second film layer 3 can be obtained by a standard semiconductor spin coating and curing process. It is preferred to design the bonding force between the second film layer 3 and the first film layer 2 to be just in a suitable intermediate state, which can not only achieve effective mechanical separation between the second film layer 3 and the first film layer 2, but also ensure that the two film layers are not separated during the standard semiconductor process (such as film growth, photolithography, etching, cleaning, etc.) on the second film layer 3.

[0039] Preferably, in order to realize a controllable and effective transfer operation of the second film layer 3 after mechanical separation, a transfer film 5 can be processed on the surface of the second film layer 3 after the second film layer 3 is formed on the first film layer 2, so as to facilitate the transfer of the separated second film layer 3 to other substrates for subsequent processing. At the same time, the transfer film 5 can also protect the surface of the second film layer 3 to reduce the damage to the surface of the second film layer 3 caused by the subsequent force applied to the surface of the second film layer 3. Specifically, the sample after the second film layer 3 is processed can be laminated to the transfer film 5 by a laminating machine, and the transfer film 5 can be removed after the second film layer 3 is separated from the first film layer 2.

[0040] Furthermore, the size of the transfer film 5 is designed to completely cover the surface of the second film layer 3, and the edge of the transfer film 5 extends beyond the edge of the surface of the second film layer 3, so that after the second film layer 3 is separated from the first film layer 2, the second film layer 3 can be transferred by taking the edge of the transfer film 5, and the transfer process will not affect the second film layer 3. The material of the transfer film 5 can be, but is not limited to, a UV film, and can be selected according to subsequent specific needs.

[0041] In some embodiments, after forming the second film layer 3 on the first film layer 2, a protective glue (not shown in the figure) may be sprayed on the surface of the second film layer 3 to protect the surface of the second film layer 3, so as to reduce the damage to the surface of the second film layer 3 caused by the subsequent application of force to the surface of the second film layer 3. The protective glue may be, but is not limited to, photoresist, and the spraying thickness of the protective glue is such that the surface of the second film layer 3 is protected from deformation when the separation force is subsequently applied.

[0042] S3. Separate the second film layer 3 from the first film layer 2 by mechanical separation, and obtain the second film layer 3 (ie, PI film), a flexible product.

[0043] Optionally, a specific implementation process of the mechanical separation method is as follows: first, the side of the substrate 1 facing away from the first film layer 2 is split, wherein the splitting method can be achieved by slicing to a certain depth but not completely cutting through the sample, or by a splitting knife, but the splitting depth does not exceed the contact surface between the second film layer 3 and the first film layer 2; then, a force is applied to the splitting position 6 from above the second film layer 3, so that the substrate 1 begins to bend and warp from the splitting position 6. At this time, since the bonding force between the first film layer 2 and the substrate 1 is greater than the bonding force between the first film layer 2 and the second film layer 3, the first film layer 2 will be connected to the substrate 1, and interface separation will be achieved between the second film layer 3 and the first film layer 2, thereby obtaining a separate second film layer 3.

[0044] Preferably, when the substrate 1 is split, the splitting position 6 can be designed to correspond to the notch 4 opened on the first film layer 2, so that the interface separation between the second film layer 3 and the first film layer 2 can be made easier during the bending and separation process of the substrate 1.

[0045] After the second film layer 3 is separated from the first film layer 2, according to the actual final needs, the second film layer 3 can be transferred to other substrates for subsequent processes using the transfer film 5 processed on the surface of the second film layer 3, or the flexible second film layer 3 can be obtained by removing it from the transfer film 5. Specifically, if the transfer film 5 is a UV film, the second film layer 3 can be separated from the transfer film 5 by UV debonding; if a protective glue (such as photoresist) is sprayed on the surface of the second film layer 3, the protective glue can be stripped by soaking in an organic solvent (such as acetone).

[0046] The manufacturing method of the flexible product of this embodiment can be applied to separating the second film layer 3 with a thickness of less than 2 um from the substrate 1 .

[0047] The flexible product manufacturing method of the present embodiment utilizes the difference in bonding force between different film layers to achieve the purpose of mechanically separating the second film layer 3 from the substrate by manufacturing a film layer interface with low bonding force, thereby effectively avoiding the dangers brought by the chemical method of releasing the sacrificial layer through corrosion by highly dangerous chemicals and the limiting influence of certain materials; and compared with the method of directly physically tearing the film off the substrate, the separation force required by the present invention is smaller, so the deformation of the second film layer 3 caused by mechanical separation will also be smaller, and at the same time, a thinner second film layer 3 can also be separated without causing the PI film layer to break due to tearing.

[0048] Embodiment 2:

[0049] like Figure 2 As shown, this embodiment provides a method for manufacturing a flexible product, specifically taking the preparation of a PI film as an example, comprising the following steps:

[0050] S1. Forming a first film layer 2 on a substrate 1.

[0051] Specifically, the substrate 1 may be selected from but not limited to common semiconductor wafers such as silicon wafers and glass wafers. The selection of the material of the first film layer 2 requires that the surface bonding force between the first film layer 2 and the second film layer 3 (i.e., PI film) is smaller than the surface bonding force between the first film layer 2 and the substrate 1. For example, the material of the first film layer 2 may be PI (polyimide), so that the surface bonding force between PI and PI is lower than the bonding force between PI and the surface of silicon or silicon oxide (i.e., glass). The first film layer 2 can be obtained by spin coating and then high-temperature curing.

[0052] S2, forming a second film layer 3 on the first film layer 2. In this embodiment, the second film layer is the PI film to be prepared. Specifically, the second film layer 3 can also be obtained by spin coating and then high-temperature curing.

[0053] S3. Grooving is performed on the surface of the second film layer 3 by dry etching or laser cutting, and the groove depth is not less than the thickness of the second film layer 3, so as to divide the film layer into several small film layers; then the second film layer 3 is peeled off at the sharp corners of the small film layers to achieve interface separation between the second film layer 3 and the first film layer 2.

[0054] Specifically, the edge and corner of the second film layer 3 can be peeled off by using sharp objects such as pointed tweezers.

[0055] In order to realize a controllable and effective transfer operation of the second film layer 3 after mechanical separation, the front side of the sheet prepared in the above step S3 is attached to the transfer film 5, and then the transfer film 5 is peeled off along the edge of the peeling film. At this time, the second film layer 3 will be separated from the substrate 1 together with the transfer film 5, and then the second film layer is dissociated from the transfer film 5 to obtain the final flexible product.

[0056] Embodiment 3:

[0057] like Figure 3 As shown, this embodiment provides a method for manufacturing a flexible product, and its preparation process is basically the same as the preparation process of the second film layer 3 in the above-mentioned embodiment 2, except that, in the above-mentioned step S3, a hard knife is used to directly cut off the second film layer 3, the first film layer 2 and the substrate 1 to obtain cut pieces, and then the edges and corners of the second film layer 3 on the cut pieces are peeled off to achieve interface separation between the second film layer 3 and the first film layer 2.

[0058] Embodiment 4:

[0059] like Figure 4 As shown, this embodiment provides a film-based flexible device product, which specifically includes the following steps:

[0060] S1. Forming a first film layer 2 on a substrate 1.

[0061] Specifically, the substrate 1 may be selected from but not limited to common semiconductor wafers such as silicon wafers and glass wafers. The selection of the material of the first film layer 2 requires that the surface bonding force between the first film layer 2 and the second film layer 3 (i.e., PI film) is smaller than the surface bonding force between the first film layer 2 and the substrate 1. For example, the material of the first film layer 2 may be PI (polyimide), so that the surface bonding force between PI and PI is lower than the bonding force between PI and the surface of silicon or silicon oxide (i.e., glass). The first film layer 2 can be obtained by spin coating and then high-temperature curing.

[0062] S2, forming a second film layer 3 on the first film layer 2. In this embodiment, the second film layer is the PI film to be prepared. Specifically, the second film layer 3 can also be obtained by spin coating and then high-temperature curing.

[0063] S3. Process the device layer 7 on the second film layer 3 using standard semiconductor processing technology, such as preparing metal leads, electrodes, film growth, photolithography, etching, etc., to obtain a specific functional structure.

[0064] S4. According to the interface separation method of the second film layer 3 and the first film layer 2 in the above-mentioned embodiments 1-3, the second film layer 3 is mechanically separated to obtain the second film layer 3 with the device layer 7.

[0065] According to actual needs, the second film layer 3 with the device layer 7 after separation is further processed in appearance, such as laser cutting, to obtain a final complete flexible device based on the second film layer, such as a flexible sensor.

[0066] In addition, in some embodiments, for preparing the second film layer 3 with the device layer 7, after forming the second film layer 3 on the first film layer 2, the second film layer 3 may be mechanically separated according to the interface separation method of the second film layer 3 and the first film layer 2 in the above embodiments 1-3, and then the separated second film layer 3 may be transferred to another substrate, and then the device layer 7 may be manufactured on the second film layer 3. This preparation method may be used for the preparation of devices with complex device layer structures that are easily damaged during separation.

[0067] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A method for manufacturing a flexible product, characterized in that: The process includes the following: forming a first film layer on a substrate, and then forming a second film layer on the first film layer, wherein the surface bonding force between the first film layer and the second film layer is smaller than the surface bonding force between the first film layer and the substrate; The second film layer is separated from the first film layer by mechanical separation to obtain a flexible product including the second film layer.

2. The method for manufacturing a flexible product according to claim 1, characterized in that: The mechanical separation method is: applying a force from one side of the second film layer to cause the substrate to crack and bend and warp, thereby achieving interface separation between the second film layer and the first film layer.

3. The method for manufacturing a flexible product according to claim 2, characterized in that: A notch is etched on the first film layer, and the splitting is performed starting from the side of the substrate facing away from the first film layer, and the splitting position of the substrate corresponds to the notch.

4. The method for manufacturing a flexible product according to claim 1, characterized in that: The mechanical separation method is: grooves are made on the surface of the second film layer by dry etching or laser cutting, the groove depth is not less than the thickness of the second film layer, and then the edges and corners of the second film layer are peeled off to achieve interface separation between the second film layer and the first film layer; Alternatively, the second film layer, the first film layer and the substrate are cut by a hard knife to obtain cut pieces, and then the second film layer on the cut pieces is peeled off to achieve interface separation between the second film layer and the first film layer.

5. The method for manufacturing a flexible product according to claim 1, characterized in that: The second film layer is a polyimide film, the first film layer is a polyimide film, and both the first film layer and the second film layer are formed by a spin coating and curing process.

6. The method for manufacturing a flexible product according to claim 1, characterized in that: After forming the second film layer on the first film layer, a transfer film is processed on the surface of the second film layer, and after the second film layer is separated from the first film layer, the transfer film is removed.

7. The method for manufacturing a flexible product according to claim 6, characterized in that: The transfer film is a UV film.

8. The method for manufacturing a flexible product according to claim 1, characterized in that: After forming the second film layer on the first film layer, spraying protective glue on the surface of the second film layer.

9. The method for manufacturing a flexible product according to claim 1, characterized in that: The second film layer is a flexible film with a thickness less than 2 um.

10. The method for manufacturing a flexible product according to any one of claims 1 to 9, characterized in that: After the second film layer is formed on the first film layer and before mechanical separation, a device layer is prepared on the second film layer, and after the second film layer is separated from the first film layer, a flexible device based on the second film layer is obtained.

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