Waveguide film imprinting method and waveguide film

Abstract

This application discloses a waveguide sheet imprinting method and a waveguide sheet. The imprinting method includes: providing a carrier film and a wafer, the carrier film containing a grating pattern; forming a coating of 3 μm or more on the surface of the carrier film facing the wafer; forming an adhesive layer of 3 μm or more on the surface of the wafer facing the carrier film; attaching the carrier film to the wafer, such that the coating on the surface of the carrier film contacts the adhesive layer on the surface of the wafer; applying pressure to transfer the grating pattern on the carrier film to the wafer; curing the wafer; and peeling the carrier film off the wafer, leaving the wafer containing the grating pattern, thus completing the transfer. By precisely controlling the thickness of the coating and adhesive layer, the thickened coating and adhesive layer can effectively fill and cover defects on the surface of the carrier film and the wafer during the transfer process, significantly improving the appearance quality of the product, reducing the scrap rate caused by surface defects, and improving the appearance yield.

Description

Technical Field

[0001] This application relates to the field of transfer printing technology, and in particular to a waveguide sheet soft film imprinting method and waveguide sheet. Background Technology

[0002] Current nanoimprint technology is prone to defects such as scratches, foreign objects, and bumps on the wafer surface during the transfer process, resulting in poor appearance quality of the transferred product and affecting product performance. Summary of the Invention

[0003] In view of this, this application proposes a waveguide sheet soft film imprinting method and a waveguide sheet, which can effectively fill and cover defects on the surface of the carrier film and the wafer surface during the transfer process, greatly improving the appearance quality of the product, reducing the scrap rate caused by surface defects, and improving the appearance yield.

[0004] The first aspect of this application proposes a method for imprinting a waveguide sheet with a soft film, comprising:

[0005] A carrier film and a wafer are provided, wherein the carrier film contains a grating pattern;

[0006] A coating of 3 μm or more is formed on the surface of the carrier film facing the wafer.

[0007] A photoresist layer of 3 μm or more is formed on the surface of the wafer facing the carrier film.

[0008] The carrier film is attached to the wafer such that the coating on the surface of the carrier film comes into contact with the adhesive layer on the surface of the wafer.

[0009] Pressure is applied to transfer the grating pattern on the carrier film to the wafer;

[0010] The wafer is cured to remove the carrier film from the wafer, leaving a wafer containing the grating pattern, thus completing the transfer process.

[0011] In some embodiments, forming a coating of 3 μm or more on the surface of the carrier film facing the wafer includes:

[0012] A uniform coating with a thickness of 3μm-5μm is formed on the surface of the carrier film using a micro-groove coating process or a slot coating process.

[0013] In some embodiments, forming an adhesive layer of 3 μm or more on the surface of the wafer facing the carrier film includes:

[0014] A uniform adhesive layer with a thickness of 3μm-5μm is formed on the surface of the wafer using a spin coating process.

[0015] In some embodiments, the process of applying a spin coating to the wafer surface to form a 3μm-5μm thick adhesive layer includes:

[0016] Provide liquid coating materials;

[0017] Liquid coating material is dropped onto the surface of the wafer so that it can uniformly cover the entire wafer surface.

[0018] The rotation speed is controlled at 1000rpm-2000rpm to drive the wafer to rotate so as to coat the wafer surface with a uniform adhesive layer with a thickness of 3μm-5μm.

[0019] In some embodiments, the application of pressure to transfer the grating pattern on the carrier film to the wafer includes:

[0020] The carrier film and the wafer are placed in an imprinting device;

[0021] Set the imprinting parameters;

[0022] After aligning the carrier film with the wafer, the imprinting equipment is started to transfer the grating pattern on the carrier film to the wafer.

[0023] In some embodiments, setting the imprinting parameters includes:

[0024] Adjust the imprinting pressure to within 5000Pa, set the imprinting speed to 1mm / s-2mm / s, and adjust the imprinting angle to 5°-10°.

[0025] In some embodiments, the carrier film is a polycarbonate film.

[0026] In some embodiments, the coating is at least one of acrylate, vinyl ester, and polyurethane.

[0027] In some embodiments, the step of peeling the carrier film off the wafer includes:

[0028] Adjust the demolding angle to 5°-10° to match the imprinting angle.

[0029] The second aspect of this application provides a waveguide sheet, which is prepared by the above-described imprinting method.

[0030] The waveguide sheet imprinting method and waveguide sheet proposed in this application, by precisely controlling the thickness of the coating and adhesive layers, enable the thickened coating and adhesive layers to effectively fill and cover defects on the surface of the carrier film and the wafer surface during the transfer process, which greatly improves the appearance quality of the product, reduces the scrap rate caused by surface defects, and improves the appearance yield. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the structure of the carrier thin film coating proposed in this application;

[0033] Figure 2 This is a schematic diagram of the wafer coating adhesive layer proposed in this application;

[0034] Figure 3 This is a flowchart illustrating the imprinting method proposed in this application.

[0035] Explanation of reference numerals in the attached figures:

[0036] 10. Carrier film; 11. Coating; 20. Adhesive layer; 30. Wafer. Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] It should be understood that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0039] It should also be understood that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or may be connected to an intermediary element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element through an intermediary element.

[0040] The terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. Descriptions using terms such as "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0041] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0042] Current nanoimprint technology is prone to defects such as scratches, foreign objects, and bumps on the wafer surface during the transfer process, resulting in poor appearance quality of the transferred product and affecting product performance.

[0043] In the field of AR diffractive waveguides, when fabricating a diffractive waveguide, a diffraction grating pattern needs to be set on a carrier film and a coating is applied to the carrier film. The coating thickness commonly used in the industry is generally 0.2μm-0.3μm. An adhesive layer also needs to be applied to the wafer surface. The adhesive layer thickness commonly used in the industry is generally 1μm-2μm. The diffraction grating pattern on the carrier film is transferred to the wafer surface using an imprinting device.

[0044] However, the above-mentioned coating configuration is prone to defects such as scratches, foreign objects and bumps on the surface during the transfer process. Furthermore, due to the thinness of the adhesive layer, it cannot effectively fill and cover surface defects, resulting in poor appearance quality of the transferred product, affecting product performance and causing a high scrap rate.

[0045] Specifically, surface defects mainly include bumps, foreign objects (dust particles, etc.), and dirt (oil stains, etc.) on the carrier film and wafer. These defects are inherent to the carrier film material and introduced by the wafer surface processing (dust particles, oil stains, etc.).

[0046] Therefore, this application proposes a waveguide sheet soft film imprinting method and waveguide sheet, which can effectively fill and cover defects on the surface of the carrier film and the wafer surface during the transfer process, greatly improving the appearance quality of the product, reducing the scrap rate caused by surface defects, and improving the appearance yield.

[0047] Please see Figures 1 to 3 This application provides a method for imprinting a waveguide sheet with a soft film, comprising:

[0048] S1, providing a carrier film 10 and a wafer 30, wherein the carrier film 10 contains a grating pattern;

[0049] S2, a coating 11 of 3 μm or more is formed on the surface of the carrier film 10 facing the wafer 30;

[0050] S3, forming an adhesive layer 20 of 3μm or more on the surface of wafer 30 facing the carrier film 10;

[0051] S4, attach the carrier film 10 to the wafer 30 so that the coating 11 on the surface of the carrier film 10 comes into contact with the adhesive layer 20 on the surface of the wafer 30.

[0052] S5, apply pressure to transfer the grating pattern on the carrier film 10 to the wafer 30;

[0053] S6, the wafer 30 is cured and the carrier film 10 is peeled off from the wafer 30 to leave the wafer 30 containing the grating pattern, thus completing the transfer.

[0054] The imprinting method of this application fills and reduces surface defects by covering the coating 11 on the thickened carrier film 10 and the adhesive layer 20 on the wafer 30, so that the two opposing surfaces of the carrier film 10 and the wafer 30 can obtain a flat plane. Therefore, no defect marks will be generated due to particles or oil stains during imprinting. At the same time, by setting the coating thickness on the surface of the wafer 30 to more than 3μm, the influence of dust and oil stains can be eliminated, and the imprinting effect can be guaranteed. The waveguide sheet after imprinting will not suffer from problems such as deterioration of optical performance, uniformity, and MTF due to excessive thickness. This ensures the optical performance of the product, greatly improves the appearance quality of the product, reduces the scrap rate caused by surface defects, and improves the appearance yield. After quality appearance inspection, the appearance performance has improved from the original 50% yield to 90% yield.

[0055] In some embodiments, the imprinting method of this application can be applied to the field of AR diffraction waveguides, in which case the carrier film 10 can be a polymer film such as polycarbonate film (PC film), and the adhesive layer 20 is a photoresist.

[0056] In some embodiments, the coating 11 may be made of at least one of acrylate, vinyl ester, and polyurethane. These materials possess good adhesion, abrasion resistance, and high-temperature resistance to ensure that the grating pattern can be transferred onto the wafer 30 with high quality.

[0057] In some embodiments, step S2 involves forming a coating 11 with a thickness of 3 μm or more on the surface of the carrier film 10 facing the wafer 30. This includes coating the surface of the carrier film 10 with a uniform coating 11 of 3 μm to 5 μm thickness using a gravure coating process or a slot coating process. Ensuring the thickness and uniformity of the coating 11 during processing is challenging. Therefore, the embodiments of this application utilize gravure coating or slot coating processes to meet the requirements of high-precision coating, thereby forming a coating 11 with uniform thickness.

[0058] For example, the microgravure coating process uses a small-diameter gravure roller and a reverse coating method, instead of the traditional pressing back roller coating method. Instead, two closely spaced rollers with the same (or similar) diameter are used to fully flatten the carrier film 10 and bring it into slight contact with the gravure roller. The coating, after being metered and applied by a doctor blade, is evenly spread on the surface of the gravure roller. As the gravure roller rotates, it continuously contacts the carrier film 10, forming wetting lines. The relative movement between the carrier film 10 and the gravure roller completes the uniform transfer of coating from the gravure roller to the carrier film 10, thereby forming a coating 11 of uniform thickness.

[0059] For example, slot coating technology is a high-precision coating method that uses an extremely fine nozzle and a high-precision coating system to expel viscous liquid or paste materials through the slots of the coating mold under certain pressure and flow rate, thereby transferring them onto the carrier film 10, thus forming a coating 11 with uniform thickness.

[0060] For example, the thickness of the coating 11 can be 3μm, 4μm or 5μm, etc. Setting the thickness of the coating 11 within the above range can effectively fill and cover the defects on the surface of the carrier film 10, greatly improve the appearance quality of the product, reduce the scrap rate caused by surface defects, and reduce production costs.

[0061] In some embodiments, step S3, forming an adhesive layer 20 with a thickness of 3 μm or more on the surface of the wafer 30 facing the carrier film 10, includes: coating a uniform adhesive layer 20 with a thickness of 3 μm-5 μm onto the surface of the wafer 30 using a spin coating process. Ensuring the thickness and uniformity of the adhesive layer 20 during processing is quite challenging. Therefore, this embodiment of the application utilizes a spin coating process to achieve high-precision preparation of the adhesive layer 20, effectively controlling its thickness and uniformity.

[0062] For example, the spin coating process relies on the centrifugal force and gravity generated when the wafer 30 rotates to spread liquid coating material (such as photoresist) evenly on the surface of the wafer 30, forming a uniform adhesive layer 20. By controlling parameters such as the rotation speed, the thickness and uniformity of the adhesive layer 20 can be precisely controlled.

[0063] For example, the thickness of the adhesive layer 20 can be 3μm, 4μm or 5μm, etc. Setting the thickness of the adhesive layer 20 within the above range can effectively fill and cover the defects on the surface of the wafer 30, greatly improve the appearance quality of the product, reduce the scrap rate caused by surface defects, and reduce production costs.

[0064] The imprinting method of this application optimizes the thickness of the coating 11 on the surface of the carrier film 10 and the adhesive layer 20 on the surface of the wafer 30. By selecting specific processes (micro-grooving coating, slot coating, or spin coating), the two opposing surfaces of the carrier film 10 and the wafer 30 can obtain a flat plane. Therefore, no defects are caused by particles or oil stains during imprinting. At the same time, by setting the coating thickness on the surface of the wafer 30 to 3-5 micrometers, the influence of dust and oil stains can be eliminated, and the imprinting effect can be guaranteed. Excessive thickness will not cause problems such as deterioration of optical performance, uniformity, and MTF of the waveguide after imprinting.

[0065] In some embodiments, step S3 involves using a spin coating process to coat a uniform adhesive layer 20 with a thickness of 3μm-5μm onto the surface of the wafer 30, including:

[0066] S31 provides liquid coating materials, such as photoresist.

[0067] S32, drop liquid coating material onto the surface of wafer 30 so that the liquid coating material can uniformly cover the entire surface of wafer 30;

[0068] S33, with a control rotation speed of 1000rpm-2000rpm, can drive the wafer 30 to rotate via a rotating device to coat the surface of the wafer 30 with a uniform adhesive layer of 3μm-5μm thickness.

[0069] During spin coating, the rotation speed has a significant impact on the thickness of the adhesive layer 20. Generally, the higher the rotation speed, the greater the centrifugal force, and the thinner the adhesive layer 20. Too low a rotation speed may lead to uneven thickness of the adhesive layer 20 and edge effects; while too high a rotation speed may make the adhesive layer 20 too thin, or even cause it to crack. In this embodiment, the rotation speed is limited to a range of 1000 rpm to 2000 rpm. Within this range, the thickness and uniformity of the adhesive layer 20 can be precisely controlled to obtain a high-quality adhesive layer 20.

[0070] Therefore, by controlling the rotation speed within the range of 1000rpm-2000rpm, it is possible to control the coating of the wafer 30 surface to form an adhesive layer 20 with a thickness of 3μm-5μm, thereby effectively filling and covering defects on the surface of the wafer 30, significantly improving the appearance quality of the product, reducing the scrap rate caused by surface defects, and lowering production costs.

[0071] For example, the rotation speed can be controlled to 1000 rpm, 1100 rpm, 1200 rpm, 1300 rpm, 1400 rpm, 1500 rpm, 1600 rpm, 1700 rpm, 1800 rpm, 1900 rpm, or 2000 rpm, etc. The thickness of the adhesive layer 20 can be precisely controlled within the range of 3 μm to 5 μm by adjusting the rotation speed.

[0072] In some embodiments, step S5, applying pressure to transfer the grating pattern on the carrier film 10 to the wafer 30, includes:

[0073] S41, the carrier film 10 and the wafer 30 are placed in the imprinting equipment;

[0074] S42, set the imprinting parameters, such as imprinting pressure, imprinting speed, and imprinting angle.

[0075] S43, after aligning the carrier film 10 with the wafer 30, start the imprinting equipment to transfer the grating pattern on the carrier film 10 to the wafer 30.

[0076] In some embodiments, step S42, setting the imprinting parameters includes: adjusting the imprinting pressure to within 5000 Pa, setting the imprinting speed to 1 mm / s-2 mm / s, and adjusting the imprinting angle to 5°-10°. Thus, adjusting the imprinting pressure to within 5000 Pa ensures that the grating pattern can be completely and clearly transferred onto the wafer, while avoiding wafer damage. Setting the imprinting speed to 1 mm / s-2 mm / s ensures that the pattern can be transferred uniformly and stably onto the wafer during the imprinting process. Adjusting the imprinting angle to 5°-10° ensures the uniformity and accuracy of the grating pattern transfer. Through the adjustment of the above parameters, the performance of the imprinted product meets the standards and is stable.

[0077] For example, the imprinting angle can be adjusted to 5°, 6°, 7°, 8°, 9° or 10°. By setting the imprinting angle, the fluidity of the material can be improved, so that the material can fill the nanostructure in the mold more evenly. This means that the adhesive layer 20 can flow smoothly and fill the nanostructure formed by the grating pattern of the carrier film 10 evenly, thereby helping to reduce the formation of bubbles and other defects and ensuring the accurate reproduction of the grating pattern.

[0078] In addition, since the material may be subjected to uneven stress distribution during the imprinting process, leading to stress concentration, which in turn can cause cracks or other forms of material failure, the above risks can be effectively reduced by adjusting the imprinting angle to 5°-10°.

[0079] In some embodiments, in step S6, the wafer 30 is cured by means of heating, ultraviolet irradiation, etc., to enhance the bonding force between the grating pattern and the wafer.

[0080] In some embodiments, step S6, the step of peeling the carrier film 10 from the wafer 30, includes adjusting the demolding angle to 5°-10° to match the imprinting angle, so as to reduce deformation or damage to the pattern during demolding. Exemplarily, the demolding angle can be adjusted to 5°, 6°, 7°, 8°, 9° or 10°.

[0081] In practical applications, the imprinting process and the demolding process are completed on the same platform. The process involves imprinting first, followed by UV curing, and finally demolding. The entire process does not require changing the platform. The imprinting and demolding processes can be performed at an upward or downward angle of 5°-10° relative to the horizontal plane. Demolding can be performed at any angle within the range of 5°-10° according to specific needs.

[0082] Matching the demolding angle and the imprinting angle means that both the demolding angle and the imprinting angle are kept within the range of 5°-10°. The specific values ​​of the demolding angle and the imprinting angle can be the same or different, as long as they are kept within the range of 5°-10°.

[0083] This application also proposes a waveguide sheet manufactured using the above-described imprinting method. Therefore, the imprinting method improves the appearance quality of the manufactured waveguide sheet, reduces the scrap rate due to surface defects, and increases the overall yield.

[0084] Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples.

[0085] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for imprinting a waveguide sheet with a soft film, characterized in that, include: A carrier film and a wafer are provided, wherein the carrier film contains a grating pattern; A coating of 3 μm or more is formed on the surface of the carrier film facing the wafer. A photoresist layer of 3 μm or more is formed on the surface of the wafer facing the carrier film. The carrier film is attached to the wafer such that the coating on the surface of the carrier film comes into contact with the adhesive layer on the surface of the wafer. Pressure is applied to transfer the grating pattern on the carrier film to the wafer; The wafer is cured to remove the carrier film from the wafer, leaving a wafer containing the grating pattern, thus completing the transfer process.

2. The imprinting method as described in claim 1, characterized in that, The process of forming a coating of 3 μm or more on the surface of the carrier film facing the wafer includes: A uniform coating with a thickness of 3μm-5μm is formed on the surface of the carrier film using a micro-groove coating process or a slot coating process.

3. The imprinting method as described in claim 2, characterized in that, The process of forming an adhesive layer of 3 μm or more on the surface of the wafer facing the carrier film includes: A uniform adhesive layer with a thickness of 3μm-5μm is formed on the surface of the wafer using a spin coating process.

4. The imprinting method as described in claim 3, characterized in that, The process of applying a spin coating to the wafer surface to form a 3μm-5μm thick adhesive layer includes: Provide liquid coating materials; Liquid coating material is dropped onto the surface of the wafer so that it can uniformly cover the entire wafer surface. The rotation speed is controlled at 1000rpm-2000rpm to drive the wafer to rotate so as to coat the wafer surface with a uniform adhesive layer with a thickness of 3μm-5μm.

5. The imprinting method as described in claim 4, characterized in that, The process of applying pressure to transfer the grating pattern on the carrier film to the wafer includes: The carrier film and the wafer are placed in an imprinting device; Set the imprinting parameters; After aligning the carrier film with the wafer, the imprinting equipment is started to transfer the grating pattern on the carrier film to the wafer.

6. The imprinting method as described in claim 5, characterized in that, The setting of the imprinting parameters includes: Adjust the imprinting pressure to within 5000Pa, set the imprinting speed to 1mm / s-2mm / s, and adjust the imprinting angle to 5°-10°.

7. The imprinting method according to any one of claims 1-6, characterized in that, The carrier film is a polycarbonate film.

8. The imprinting method according to any one of claims 1-6, characterized in that, The coating is at least one of acrylate, vinyl ester, and polyurethane.

9. The imprinting method as described in claim 6, characterized in that, The step of peeling the carrier film off the wafer includes: Adjust the demolding angle to 5°-10° to match the imprinting angle.

10. A waveguide sheet, characterized in that, It is prepared by the imprinting method as described in any one of claims 1-9.

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