Microlens integrated structure and manufacturing method thereof

Abstract

The application discloses a microlens integrated structure and a manufacturing method thereof. The microlens integrated structure comprises a substrate, at least one microlens and at least two supporting blocks; the microlens and the supporting blocks are distributed on the surface of the substrate and are integrally arranged with the substrate; two sides of one of the microlenses are respectively provided with at least one of the supporting blocks, and the height of the top end of the supporting block is higher than the height of the top end of the microlens. The microlens and the supporting block are integrated on one device, the device is formed at one time through a semiconductor etching process, the height and position accuracy can be ensured, and the coupling optical power loss caused by the mounting process is reduced.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor chip manufacturing technology, specifically relating to a microlens integrated structure and its fabrication method. Background Technology

[0002] Silicon microlenses are used in the field of optical communication. When used in optical communication modules, square pads are generally used as support blocks to mount the microlenses. The positional accuracy deviation and mounting height of the mounting process have a significant impact on the coupling optical power of the product. Summary of the Invention

[0003] The main objective of this invention is to provide a microlens integrated structure and its fabrication method to overcome the shortcomings of the prior art.

[0004] To achieve the aforementioned objectives, the technical solutions adopted in the embodiments of the present invention include:

[0005] This invention provides a microlens integrated structure, including a substrate, at least one microlens, and at least two support blocks; the microlens and support blocks are distributed on the surface of the substrate and are integrally formed with the substrate; at least one support block is provided on both sides of one of the microlenses, and the height of the top of the support block is higher than the height of the top of the microlens.

[0006] Furthermore, the microlens integrated structure includes one or more microlens groups, each microlens group comprising multiple microlenses, and at least one support block is provided on each side of one of the microlens groups.

[0007] Furthermore, the microlens is hemispherical.

[0008] This invention also provides a method for fabricating the aforementioned microlens integrated structure, comprising:

[0009] S1. Provide a substrate and define a first region and a second region on the surface of the substrate. The first region is used to set at least two support blocks, and the second region is used to set at least one microlens. At least one support block is set on each side of one of the microlenses.

[0010] S2. A metal mask is disposed in the first region of the substrate surface;

[0011] S3. A photoresist layer is deposited on the surface of the substrate, and then the photoresist layer is exposed and developed to remove the photoresist layer that is not distributed in the second region.

[0012] S4. The photoresist layer remaining on the second region is formed into a glue ball by photoresist hot melting method;

[0013] S5. Etching the surface of the gel ball and the substrate, wherein the etching rate of the etching reagent on the metal mask is less than the etching rate of the etching reagent on the gel ball, and the ratio of the etching rate of the etching reagent on the gel ball to the etching rate of the etching reagent on the substrate material is 0.9 to 1.1:1, so that after the gel ball is completely etched, the pattern of the gel ball is completely transferred to the substrate, thereby forming the microlens in the second region on the substrate surface;

[0014] S6. Remove the metal mask to form the support block in a first region on the substrate surface.

[0015] Furthermore, in step S2, the thickness of the metal mask is 3-4 μm.

[0016] Furthermore, in step S3, the thickness of the photoresist layer can be determined by the formula... The calculation is performed, where h is the thickness of the photoresist layer, R is the radius of curvature of the prepared sphere, and D is the bottom diameter of the prepared sphere.

[0017] Furthermore, in step S4, the heating temperature of the photoresist hot melt method is 150-200°C, and the heating time is 10-20 minutes.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention integrates a microlens and a support block onto a single device. The device is formed in one step using a semiconductor etching process, which ensures its height and positional accuracy and reduces the loss of coupled optical power caused by the mounting process. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the microlens integrated structure in Embodiment 1 of this application.

[0022] Figures 2-10 This is a schematic diagram of the fabrication process of the microlens integrated structure.

[0023] Figure 11 This is a schematic diagram of the microlens integrated structure in Embodiment 2 of this application.

[0024] Explanation of reference numerals in the attached figures: 1. Silicon substrate, 2. Microlens, 3. Support block, 4. Photoresist, 5. First photoresist protrusion, 6. Metal mask, 7. Second photoresist protrusion, 8. Heating plate, 9. Photoresist ball. Detailed Implementation

[0025] In view of the shortcomings of existing technologies, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. Its main function is to integrate the microlens and the support block into one unit, and to form the device in a single step using a semiconductor etching process. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0026] One aspect of the present invention provides a microlens integrated structure, including a substrate, at least one microlens and at least two support blocks; the microlens and support blocks are distributed on the surface of the substrate and are integrally formed with the substrate; at least one support block is provided on both sides of one of the microlenses, and the height of the top of the support block is higher than the height of the top of the microlens.

[0027] In some preferred embodiments, the microlens integrated structure includes one or more microlens groups, each microlens group comprising a plurality of microlenses, and at least one support block is provided on each side of one of the microlens groups.

[0028] In some preferred embodiments, the microlens is hemispherical.

[0029] In some preferred embodiments, the substrate is a silicon substrate.

[0030] This invention also provides a method for fabricating the aforementioned microlens integrated structure, comprising:

[0031] S1. Provide a substrate and define a first region and a second region on the surface of the substrate. The first region is used to set at least two support blocks, and the second region is used to set at least one microlens. At least one support block is set on each side of one of the microlenses.

[0032] S2. A metal mask is disposed in the first region of the substrate surface;

[0033] S3. A photoresist layer is deposited on the surface of the substrate, and then the photoresist layer is exposed and developed to remove the photoresist layer that is not distributed in the second region.

[0034] S4. The photoresist layer remaining on the second region is formed into a glue ball by photoresist hot melting method;

[0035] S5. Etching the surface of the gel ball and the substrate, wherein the etching rate of the etching reagent on the metal mask is less than the etching rate of the etching reagent on the gel ball, and the ratio of the etching rate of the etching reagent on the gel ball to the etching rate of the etching reagent on the substrate material is 0.9 to 1.1:1, so that after the gel ball is completely etched, the pattern of the gel ball is completely transferred to the substrate, thereby forming the microlens in the second region on the substrate surface;

[0036] S6. Remove the metal mask to form the support block in a first region on the substrate surface.

[0037] In some preferred embodiments, in step S2, the thickness of the metal mask is 3-4 μm.

[0038] In some preferred embodiments, in step S3, the thickness of the photoresist layer can be determined by the formula... The calculation is performed, where h is the thickness of the photoresist layer, R is the radius of curvature of the prepared sphere, and D is the bottom diameter of the prepared sphere.

[0039] In some preferred embodiments, in step S4, the heating temperature of the photoresist hot melt method is 150-200°C, and the heating time is 10-20 minutes.

[0040] The present invention integrates a microlens and a support block onto a single device. The device is formed in one step using a semiconductor etching process, which ensures its height and positional accuracy and reduces the loss of coupled optical power caused by the mounting process.

[0041] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0042] Example 1

[0043] This invention provides a microlens integrated structure, such as... Figure 1 As shown, the device includes a silicon substrate 1, a microlens group, and two support blocks 3. In this embodiment, the microlens group includes two microlenses 2, and a support block 3 is provided on each side of the microlens group. The microlenses 2 and the support blocks 3 are distributed on the surface of the silicon substrate 1 and are integrally formed with the silicon substrate 1. The height of the top of the support block 3 is higher than the height of the top of the microlenses 2, and the support block 3 is spaced a certain distance from the edge of the silicon substrate 1.

[0044] The microlens integrated structure in this embodiment is fabricated through the following steps:

[0045] Step 1: As Figure 2 As shown, a photoresist 4 with a thickness of 3-5 μm is uniformly coated on the surface of silicon substrate 1 using a spin coater;

[0046] Step 2: As Figure 3 As shown, a photolithography machine is used to expose a silicon substrate 1 coated with photoresist 4. After exposure, the silicon substrate 1 is placed in a developing solution. In the areas of the silicon substrate 1 that are irradiated by UV light, the photoresist 4 dissolves in the developing solution, exposing the underlying substrate. In the areas of the silicon substrate 1 that are not irradiated by UV light, the photoresist 4 remains, forming first photoresist protrusions 5 in the middle and on both sides of the surface of the silicon substrate 1. The first photoresist protrusion 5 in the middle is defined as the second region, and the area between the first photoresist protrusions 5 is defined as the first region.

[0047] Step 3: As Figure 4 As shown, after development, a magnetron sputtering device is used to perform metal Cr sputtering deposition, depositing metal on the surface of the first photoresist protrusion 5 and the silicon substrate 1. Then, through a metal stripping process, the metal on the first photoresist protrusion 5 and the surface is removed, while the metal in direct contact with the silicon substrate 1 is retained, forming a metal mask 6 with a thickness of 3-4 μm in the first region.

[0048] Step 4: As Figure 5 As shown, a layer of photoresist 4 with a thickness of 15 μm is uniformly coated on the surface of the silicon substrate 1 to encapsulate the metal mask 6. This thickness is determined by the formula... The calculation yields h, where h is the thickness of the photoresist layer, R is the radius of curvature of the prepared sphere, and D is the bottom diameter of the prepared sphere.

[0049] Step 5: As Figure 6 As shown, a photolithography machine is used to expose the silicon substrate 1 coated with photoresist 4. After exposure, the silicon substrate 1 is placed in a developer. In the area of ​​the silicon substrate 1 that is irradiated by UV light, the photoresist 4 dissolves in the developer, exposing the underlying substrate. In the area of ​​the silicon substrate 1 that is not irradiated by UV light, a second photoresist protrusion 7 is formed in the second region.

[0050] Step 6: As Figure 7 As shown, the silicon substrate 1 with the second photoresist protrusion 7 is placed on the heating plate 8, and the heating temperature is 150-200℃ for 10-20 minutes. Figure 8 As shown, the second photoresist protrusion 7 is formed into a glue ball 9 by photoresist hot melting method;

[0051] Step 7: As Figure 9 and Figure 10As shown, the prepared silicon substrate 1 is placed in a dry etching apparatus. The etching rate of the silicon substrate 1 is required to be 0.9 to 1.1:1 with the etching rate of the photoresist 4. The etching rate of the metal material in this etching environment is much lower than that of the silicon substrate. After the photoresist ball 9 is completely etched, its pattern has been completely transferred to the silicon substrate 1. The metal layer covering area on both sides of the photoresist ball 9 is protected by the metal mask 6. The silicon substrate 1 is not etched, thus forming a raised support block 3. The remaining metal layer is removed by the chemical agent chromium etching solution to form a microlens 2 with a height lower than the support block 3.

[0052] Example 2

[0053] This invention provides a microlens integrated structure, such as... Figure 11 As shown, the device includes a silicon substrate 1, a microlens group, and two support blocks 3. In this embodiment, the microlens group includes two microlenses 2, and a support block 3 is provided on each side of the microlens group. The microlenses 2 and the support blocks 3 are distributed on the surface of the silicon substrate 1 and are integrally formed with the silicon substrate 1. The height of the top of the support block 3 is higher than the height of the top of the microlens 2, and the support block 3 is located at the edge of the surface of the silicon substrate 1.

[0054] The fabrication method of the microlens integrated structure in this embodiment is basically the same as that of the microlens integrated structure in Embodiment 1. The difference lies in step 2, which is as follows: using a photolithography machine, the silicon substrate 1 coated with photoresist 4 is exposed. After exposure, the silicon substrate 1 is placed in a developing solution. In the area of ​​the silicon substrate 1 irradiated by UV light, the photoresist 4 dissolves in the developing solution, exposing the underlying substrate. In the area of ​​the silicon substrate 1 not irradiated by UV light, the photoresist 4 remains and forms a first photoresist protrusion 5 in the middle of the surface of the silicon substrate 1. The first photoresist protrusion 5 is defined as the second region, and the areas on both sides of the first photoresist protrusion 5 are defined as the first region.

[0055] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0056] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. A method for fabricating a microlens integrated structure, characterized in that... include: The microlens integrated structure includes a substrate, one or more microlens groups, and at least two support blocks. Each microlens group includes two microlenses. The microlenses and support blocks are distributed on the surface of the substrate and are integrally formed with the substrate. At least one support block is provided on each side of one of the microlens groups, and the height of the top of the support block is higher than the height of the top of the microlens. The microlens is hemispherical. The specific production method is as follows: S1. Provide a substrate and define a first region and a second region on the surface of the substrate. The first region is used to set at least two support blocks, and the second region is used to set at least one microlens group. At least one support block is set on each side of one of the microlens groups. S2. A metal mask is disposed in a first region on the surface of the substrate, the thickness of the metal mask being 3-4 μm; S3. A photoresist layer is deposited on the surface of the substrate, and then the photoresist layer is exposed and developed to remove the photoresist layer that is not distributed in the second region. The thickness of the photoresist layer can be calculated by the formula, where h is the thickness of the photoresist layer, R is the radius of curvature of the prepared gel ball, and D is the bottom diameter of the prepared gel ball. S4. The photoresist layer remaining on the second region is formed into a ball by photoresist hot melting method. The heating temperature of the photoresist hot melting method is 150~200℃ and the heating time is 10~20min. S5. Etching the surface of the gel ball and the substrate, wherein the etching rate of the etching reagent on the metal mask is less than the etching rate of the etching reagent on the gel ball, and the ratio of the etching rate of the etching reagent on the gel ball to the etching rate of the etching reagent on the substrate material is 0.9~1.1:1, so that after the gel ball is completely etched, the pattern of the gel ball is completely transferred to the substrate, thereby forming the microlens in the second region on the substrate surface; S6. Remove the metal mask to form the support block in a first region on the substrate surface.

Images