Lcos device and method of manufacturing the same

Abstract

The application relates to an LCOS device and a manufacturing method thereof. In the manufacturing method, a first substrate is formed, the first substrate comprises a first substrate, a buffer medium layer formed on the surface of the first substrate, a plurality of pixel electrodes formed on the surface of the buffer medium layer, and a first hybrid bonding layer, then the first substrate is vertically hybrid bonded with a second substrate, the surface of the pixel electrode in contact with the buffer medium layer is a light reflection surface, the reflection performance is better, the pixel yield is improved, the pixel electrode and the pixel driving circuit are formed on the first substrate and the second substrate respectively, the selection of the specific manufacturing process and the process platform is more flexible, the cost and efficiency control are facilitated, the first substrate can be pre-screened before being bonded with the second substrate, and the yield of the LCOS device is improved. The LCOS device can be formed by using the manufacturing method.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to an LCOS device and a method for manufacturing an LCOS device. Background Technology

[0002] With the maturity of laser light source technology, the market share of projection products based on LCOS (Liquid Crystal on Silicon) chips is gradually increasing. In the LCOS chip process, a silicon substrate is typically used to form a CMOS active array, and then pixel electrodes (also known as reflective electrodes) with reflective functions are fabricated based on the CMOS active array substrate.

[0003] However, the pixel electrode surface formed by the current LCOS chip process is prone to defects such as hillocks or corrosion pits, which are difficult to solve by CMP (chemical mechanical polishing) because CMP will cause problems such as scratches and electrochemical corrosion on the metal surface. When other structures are made on the pixel electrode, the heat introduced can easily aggravate the surface defects of the pixel electrode, resulting in poor pixel electrode reflectivity and further affecting pixel yield. Summary of the Invention

[0004] To optimize the reflectivity of pixel electrodes and improve pixel yield, this invention provides a method for manufacturing an LCOS device and an LCOS device.

[0005] On one hand, the present invention provides a method for manufacturing an LCOS device, the method comprising:

[0006] A first substrate is formed, the first substrate including a first substrate, a buffer dielectric layer formed on the surface of the first substrate, a plurality of pixel electrodes formed on the surface of the buffer dielectric layer, and a first hybrid bonding layer. The first hybrid bonding layer includes a first passivation layer covering the buffer dielectric layer and the plurality of pixel electrodes, and a first metal connection structure formed within the first passivation layer and connecting each of the pixel electrodes. The surface of the pixel electrode in contact with the buffer dielectric layer is a light-reflecting surface.

[0007] The first substrate is vertically bonded to a second substrate. The second substrate includes a pixel driving circuit formed on the second substrate and a second hybrid bonding layer. The second hybrid bonding layer includes a second passivation layer formed on the second substrate and a second metal connection structure formed in the second passivation layer and connected to the pixel driving circuit. The first hybrid bonding layer and the second hybrid bonding layer are hybrid bonded.

[0008] Optionally, before or after the first substrate and the second substrate are vertically bonded together, the first substrate is thinned from the side of the first substrate away from the pixel electrode.

[0009] Optionally, after thinning the first substrate, the remaining first substrate is patterned to form a metasurface structure.

[0010] Optionally, after the first substrate and the second substrate are vertically bonded together, the first substrate is removed.

[0011] Optionally, forming the first substrate includes:

[0012] The buffer dielectric layer and the electrode material layer are sequentially stacked on the first substrate;

[0013] The electrode material layer is patterned to form the plurality of pixel electrodes;

[0014] A dielectric material is deposited and planarized to form the first passivation layer, the first passivation layer covering the buffer dielectric layer and the plurality of pixel electrodes; and

[0015] The first metal connection structure is formed in the first passivation layer to obtain the first substrate.

[0016] Optionally, forming the first metal connection structure in the first passivation layer includes:

[0017] Openings are formed in the first passivation layer to expose the plurality of pixel electrodes; and

[0018] Metal material is filled into the opening to form a first metal pillar, one end of which is connected to the pixel electrode below, and the other end is flush with the top surface of the first passivation layer.

[0019] Optionally, forming the first metal connection structure in the first passivation layer includes:

[0020] A groove is formed on the top of the first passivation layer corresponding to each pixel electrode;

[0021] The first passivation layer is etched from the bottom surface of the groove to form an opening exposing the plurality of pixel electrodes; and

[0022] Metal material is filled into the opening and the groove to form a metal bonding pad located in the groove and a first metal pillar located in the opening and connected to the pixel electrode. One end of the metal bonding pad is connected to the first metal pillar and the other end is flush with the top surface of the first passivation layer.

[0023] Optionally, the buffer medium layer includes a stacked structure of a nitrided layer and an oxide layer.

[0024] On the other hand, the present invention provides an LCOS device, the LCOS device comprising:

[0025] A first substrate includes a buffer dielectric layer, a plurality of pixel electrodes formed on one side surface of the buffer dielectric layer, and a first hybrid bonding layer. The first hybrid bonding layer includes a first passivation layer covering the buffer dielectric layer and the plurality of pixel electrodes, and a first metal connection structure formed within the first passivation layer and connecting each of the pixel electrodes.

[0026] A second substrate is vertically bonded to the first substrate. The second substrate includes a pixel driving circuit formed on a substrate and a second hybrid bonding layer. The second hybrid bonding layer includes a second passivation layer formed on the substrate and a second metal connection structure formed in the second passivation layer and connected to the pixel driving circuit. The first hybrid bonding layer and the second hybrid bonding layer form a hybrid bond. The surface of the pixel electrode that contacts the buffer dielectric layer is a light-reflecting surface.

[0027] Optionally, the first substrate further includes a first substrate located on the other side of the buffer medium layer.

[0028] Optionally, the first substrate is a patterned metasurface structure.

[0029] The manufacturing method and LCOS device provided by this invention have the following technical effects:

[0030] First, the pixel electrode is formed on the surface of the buffer medium layer and the surface of the pixel electrode in contact with the buffer medium layer (i.e., the bottom surface of the pixel electrode) is a light-reflecting surface. The surface of the pixel electrode in contact with the buffer medium layer has a lower defect density and better reflection performance than the top surface, which helps to improve pixel yield.

[0031] Secondly, the pixel electrode and the pixel driving circuit are formed on the first substrate and the second substrate respectively, and the first substrate and the second substrate are vertically bonded together. Without affecting the connection between the pixel electrode and the pixel driving circuit, the cross-influence of the manufacturing process can be avoided. Compared with forming the pixel electrode on the pixel driving circuit substrate, the specific manufacturing process and process platform selection are more flexible, which helps to control costs and performance.

[0032] Furthermore, since the first substrate does not have a pixel driving circuit, the manufacturing process is simpler and the cost is lower. Before bonding with the second substrate, the first substrate can be pre-screened, which helps to improve the yield of the LCOS device without significantly affecting the manufacturing cost and efficiency. Attached Figure Description

[0033] Figure 1 This is a schematic flowchart illustrating the manufacturing method of the LCOS device according to an embodiment of the present invention.

[0034] Figures 2A to 2G This is a cross-sectional schematic diagram of a method for manufacturing an LCOS device according to an embodiment of the present invention. Detailed Implementation

[0035] The LCOS device and its manufacturing method of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description. It should be noted that the terms "first," "second," etc., used in the specification are used to distinguish between similar elements and are not necessarily used to describe a specific order or chronological sequence. It should be understood that these terms can be replaced where appropriate. It should be understood that the accompanying drawings are in a very simplified form and use non-precise scales, and are only used to facilitate clarity in illustrating the embodiments of the present invention. Furthermore, spatial relative terms are intended to include different orientations in use or operation besides the orientation of the device as depicted in the figures. For example, if the structure in the figures is inverted or positioned in other different ways (e.g., rotated), the exemplary term "on" may also include "below" and other orientational relationships.

[0036] Reference Figure 1 The method for fabricating an LCOS device according to an embodiment of the present invention includes: step S1, forming a first substrate, the first substrate including a first substrate, a buffer dielectric layer formed on the surface of the first substrate, a plurality of pixel electrodes stacked on the surface of the buffer dielectric layer, and a first hybrid bonding layer, the first hybrid bonding layer including a first passivation layer covering the buffer dielectric layer and the plurality of pixel electrodes, and a first metal connection structure formed in the first passivation layer and connected to each of the pixel electrodes, the surface of the pixel electrode in contact with the buffer dielectric layer being a light-reflecting surface; step S2, vertically bonding the first substrate to a second substrate, and thinning the first substrate from the side of the first substrate away from the pixel electrodes, the second substrate including a pixel driving circuit formed on the second substrate and a second hybrid bonding layer, the second hybrid bonding layer including a second passivation layer formed on the second substrate and a second metal connection structure formed in the second passivation layer and connected to the pixel driving circuit, the first hybrid bonding layer and the second hybrid bonding layer being hybrid bonded.

[0037] The LCOS device described in this embodiment of the invention can be any LCOS structure or LCOS product including an LCOS pixel driving circuit and pixel electrodes, such as an LCOS pixel substrate or an LCOS chip. As an example, Figure 1In the method for manufacturing the LCOS device shown, step S1 may include the following process.

[0038] Reference Figure 2A First, a buffer dielectric layer 110 and an electrode material layer 120 are sequentially stacked on the first substrate 100.

[0039] The first substrate 100 can be a suitable support substrate, such as a silicon substrate, a germanium-silicon substrate, a silicon carbide substrate, a silicon-on-insulator (SOI) substrate, a germanium-on-insulator substrate, a germanium-silicon-on-insulator substrate, or a III-V compound substrate (e.g., a gallium nitride substrate or a gallium arsenide substrate), etc., but is not limited thereto. Since the first substrate 100 is not used to form a pixel driving circuit in this embodiment, the first substrate 100 can also be a support substrate made of a non-semiconductor material. Here, as an example, the first substrate 100 is a silicon substrate.

[0040] The buffer dielectric layer 110 serves as an isolation buffer between the first substrate 100 and the electrode material layer 120. In this embodiment, the surface of the pixel electrode subsequently formed that contacts the buffer dielectric layer 110 is a reflective surface. That is, when the LCOS device to be fabricated is operating, light passes through the buffer dielectric layer 110 and is incident on the pixel electrode surface and reflected, thus the buffer dielectric layer 110 also serves as a light transmission layer. The material and thickness of the buffer dielectric layer 110 can be specifically selected according to the characteristics such as the wavelength of the incident light, preferably to enhance light reflection. The buffer dielectric layer 110 may include, for example, a stacked structure of a nitride layer (such as silicon nitride) and an oxide layer (such as silicon oxide). Figure 2A As shown, in one embodiment, the buffer medium layer 110 includes a silicon nitride layer 111 and a silicon oxide layer 112 sequentially stacked on the surface of the first substrate 100.

[0041] The electrode material layer 120 is used to form the pixel electrode in the LCOS device. It may be made of a material with good reflectivity (such as aluminum and silver). For example, the electrode material layer 120 is made of aluminum.

[0042] Reference Figure 2B For example, photolithography and etching processes are performed to pattern the electrode material layer 120 to form multiple pixel electrodes 10.

[0043] Reference Figure 2C A dielectric material (such as silicon oxide) is deposited and planarized (such as CMP) to form a first passivation layer 130, which covers the buffer dielectric layer 110 and the plurality of pixel electrodes 10. The first passivation layer 130 may be a single-layer or multi-layer structure; as an example, the first passivation layer 130 is a silicon oxide layer.

[0044] During the formation of the pixel electrode 10 and the first passivation layer 130, due to the inherent properties of the metal (e.g., aluminum is reactive and has a low recrystallization temperature) and the influence of thermal parameters, at least one of the defects, such as hillocks 10a or corrosion pits, is easily generated on the surface of the pixel electrode 10 covered by the first passivation layer 130, which affects the reflection effect if the surface is used as a reflective surface. However, for the surface of each pixel electrode 10 that contacts the buffer dielectric layer 110, since it is attached to the buffer dielectric layer 110 when the electrode material layer 120 is formed, it does not change much during the formation of the pixel electrode 10 and the first passivation layer 130, thus exhibiting better flatness and lower defect density.

[0045] Subsequently, a first metal connection structure is formed in the first passivation layer 130. As an example, the first metal connection structure is formed using a damascus process. This process may include, for example, the following steps: First, using photolithography and etching processes, openings are formed in the first passivation layer 130 to expose multiple underlying pixel electrodes 10; then, for example, an electroplating or electroless plating process is performed to fill the openings with a metal material (such as copper or other suitable material), which may also be deposited outside the openings; then, a planarization process (such as CMP) is performed to remove the metal material outside the openings, leaving a first metal pillar 140 within the openings. One end of the first metal pillar 140 is connected to the underlying pixel electrode 10, and the other end is flush with the upper surface of the first passivation layer 130, thus forming the first metal connection structure with the first metal pillar 140 connected to each pixel electrode 10. In this embodiment, the first passivation layer 130 and the first metal pillar 140 form a first hybrid bonding layer HB1.

[0046] The specific structure of the first metal connection structure is not limited to... Figure 2D The first metal pillar 140 shown may, as needed, include at least one of the following metal structures: a metal pillar, a metal layer, and a metal pad. For example, in another embodiment, in... Figure 2C Based on the process shown, forming the first metal connection structure may include the following steps: forming a groove on the top of the first passivation layer 130 corresponding to each pixel electrode 10; then, etching the first passivation layer 130 downward from the bottom of the groove to form an opening exposing the plurality of pixel electrodes 10, the opening being smaller than the width of the groove; then, filling the opening and the groove with metal material, the metal material may also be deposited outside the groove, followed by a planarization process (such as CMP) to remove the metal material located outside the groove, the metal material in the groove forming a metal bonding pad, and forming a metal pillar connected to the metal bonding pad and the pixel electrode 10 in the opening below the groove, the upper surface of the metal bonding pad being flush with the upper surface of the first passivation layer 130.

[0047] In yet another embodiment, in Figure 2C Based on the process shown, forming the first metal connection structure may include the following steps: First, openings exposing each pixel electrode 10 are formed in the first passivation layer 130; then, the first passivation layer 130 around the openings is etched to widen the top of the openings; then, metal material is filled into the openings, and the metal material may also be deposited outside the openings; then, a planarization process (such as CMP) is performed to remove the metal material located outside the openings, forming a metal bonding pad at the top of the openings, and forming a metal pillar located below the metal bonding pad and connected to the pixel electrode 10 inside the openings, with the upper surface of the metal bonding pad flush with the upper surface of the first passivation layer 130.

[0048] Through the above process, a first substrate W1 is formed based on the first substrate 100.

[0049] Figure 2E A cross-sectional structure is shown after the first substrate W1 and the second substrate W2 are bonded together. (Refer to...) Figure 2E In this embodiment, step S2 vertically bonds the first substrate W1 to a second substrate W2. The second substrate W2 is used to house the pixel driving circuit of the LCOS device. The pixel driving circuit controls the pixels in the LCOS device. For each pixel, the corresponding pixel driving circuit includes, for example, at least one MOS transistor and at least one capacitor. The second substrate W2 can be formed using known logic processes. The second substrate 200 is, for example, a silicon substrate or other semiconductor substrate. The second substrate 200 may contain structures such as ion-doped regions and isolation regions (not shown). The pixel driving circuit may include logic devices formed on the surface region of the second substrate 200 and metal interconnect structures formed on the second substrate 200. Figure 2E The pixel driving circuit 210 shown indicates that a pixel driving circuit is formed on the second substrate 200, but does not constitute a limitation on the shape and position of the pixel driving circuit.

[0050] Reference Figure 2E The second substrate W2 includes a pixel driving circuit 210 formed on the second substrate 200 and a second hybrid bonding layer HB2. The second hybrid bonding layer HB2 may include a second passivation layer 220 formed on the second substrate 200 and a second metal connection structure formed within the second passivation layer 220 and connected to the pixel driving circuit 210. Depending on the specific design, the second metal connection structure may include at least one of metal structures such as metal pillars, metal layers, and metal pads. As an example, such as... Figure 2EAs shown, the second metal connection structure includes a second metal pillar 21 and a metal bonding pad 22 located within the second passivation layer 220. One end of the second metal pillar 21 extends toward the second substrate 200 to facilitate connection with the pixel driving circuit 210, and the other end is connected to the metal bonding pad 22. The surface of the metal bonding pad 22 away from the second metal pillar 21 is flush with the upper surface of the second passivation layer 220.

[0051] When bonding the first substrate W1 and the second substrate W2, the first hybrid bonding layer HB1 on the first substrate W1 and the second hybrid bonding layer HB2 on the second substrate W2 are aligned and hybrid bonding is performed. Through hybrid bonding, the first passivation layer 130, the second passivation layer 220, the first metal connection structure, and the second metal connection structure, which are positioned opposite each other, are bonded together. By bonding the first metal connection structure and the second metal connection structure together, each pixel electrode 10 formed on the first substrate W1 can be connected to the pixel driving circuit formed on the second substrate W2. In this embodiment, the cross-sectional area of ​​the pixel electrode 10 needs to meet the reflection requirements. Correspondingly, the connection density of the first metal pillars 140 connected to each pixel electrode 10 is low, which facilitates meeting the alignment accuracy and geometric dimension requirements during hybrid bonding.

[0052] Reference Figure 2F After the first substrate W1 and the second substrate W2 are bonded, or in another embodiment before the first substrate W1 and the second substrate W2 are bonded, the first substrate W1 can be thinned from the side of the first substrate 100 opposite to the pixel electrode 10. Since the side of the first substrate 100 opposite to the pixel electrode 10 is the side where light is incident during the operation of the LCOS device, the amount of thinning can be determined according to the optical path design. As an example, the first substrate 100 can be thinned or removed by employing a suitable thinning process.

[0053] like Figure 2F As shown, in one embodiment, the first substrate 100 is thinned while retaining a portion of its thickness by employing a suitable thinning process. Figure 2G A cross-sectional structure of the remaining thinned first substrate 100 is shown. (Refer to...) Figure 2GAfter the first substrate W1 and the second substrate W2 are mixed and bonded and the first substrate 100 is thinned, the remaining first substrate 100 can be patterned to form a metasurface structure 100a. In this embodiment, the metasurface structure 100a includes a series of micro-units formed from the first substrate 100. By patterning the first substrate 100, these micro-units are formed into geometric shapes and arrangements as needed. The metasurface structure 100a can be used to control the phase and amplitude of incident light to control the light beam, and thus can be used to optimize the performance of the LCOS device. The patterning process of the first substrate 100 can be specifically set as needed. For the conventional process of fabricating pixel electrodes on the pixel driving circuit substrate, the thermal budget will cause the reflective surface of the pixel electrode to deteriorate. Therefore, it is difficult to deposit semiconductor materials (such as silicon) to fabricate metasurface structures after the pixel electrode is formed. However, in this embodiment, after bonding, the first substrate 100 can be processed from the side away from the pixel electrode 10 to form the metasurface structure 100a. The process is simple and does not affect the reflective surface of the pixel electrode 10.

[0054] In the LCOS device fabrication method described in the above embodiments, on the one hand, by bonding the first substrate W1 and the second substrate W2, it is convenient to connect the pixel electrode 10 to the corresponding pixel driving circuit 210. On the other hand, the pixel electrode 10 is formed on the surface of the buffer dielectric layer 110, and the surface of the pixel electrode 10 in contact with the buffer dielectric layer 110 (i.e., the bottom surface of the pixel electrode 10) is the light-reflecting surface. Compared with the surface of the pixel electrode 10 away from the buffer dielectric layer 110, the reflection performance can be improved, which helps to improve the pixel yield. Moreover, by forming the pixel electrode 10 and the pixel driving circuit 210 on the first substrate W1 and the second substrate W2 respectively, the fabrication process can be simplified. Compared to the traditional process of fabricating pixel electrodes on the pixel driving circuit substrate, the cross-influence of processes in this embodiment allows for more flexible selection of specific manufacturing conditions and process platforms for the formation of the first substrate W1 and the second substrate W2, which helps in cost and performance control. In addition, the first substrate W1 does not have a pixel driving circuit, making the manufacturing process simpler and the cost lower. In some embodiments, the first substrate W1 can be pre-screened before bonding with the second substrate W2 to select the first substrate W1 that meets the requirements such as reflectivity. Using the first substrate W1 that meets the requirements to bond with the second substrate W2 can improve the product yield without significantly affecting the manufacturing cost and efficiency.

[0055] This invention also relates to an LCOS device, which can be formed using the LCOS device manufacturing method described in the above embodiments.

[0056] Reference Figure 2F and Figure 2GIn this embodiment of the invention, the LCOS device includes a first substrate W1 and a second substrate W2 that are vertically bonded together. Detailed description follows.

[0057] The first substrate W1 includes a buffer dielectric layer 110, a plurality of pixel electrodes 10 formed on one side surface of the buffer dielectric layer 110, and a first hybrid bonding layer HB1. The first hybrid bonding layer HB1 includes a first passivation layer 130 covering the buffer dielectric layer 110 and the plurality of pixel electrodes 10, and a first metal connection structure formed within the first passivation layer 130 and connecting the pixel electrodes 10. As an example, the first metal connection structure includes a plurality of first metal pillars 140, one end of which is connected to the pixel electrode 10 below, and the other end is flush with the surface of the first passivation layer 130 facing the second substrate W2.

[0058] like Figure 2F As shown, in some embodiments, the first substrate W1 further includes a first substrate 100 located on the other side of the buffer dielectric layer 110 (i.e., the side opposite to the pixel electrode 10). Optionally, the first substrate 100 is a patterned metasurface structure.

[0059] The second substrate W2 includes a pixel driving circuit 210 formed on a substrate (e.g., the second substrate 200 described above) and a second hybrid bonding layer HB2. The second hybrid bonding layer HB2 includes a second passivation layer 220 formed on the second substrate 200 and a second metal connection structure formed within the second passivation layer 220 and connected to the pixel driving circuit 210. As an example, the second metal connection structure includes a second metal pillar 21 and a metal bonding pad 22 located within the second passivation layer 220. One end of the second metal pillar 21 extends toward the second substrate 200 to facilitate connection with the pixel driving circuit 210, and the other end is connected to the metal bonding pad 22. The surface of the metal bonding pad 22 away from the second metal pillar 21 is flush with the surface of the second passivation layer 220 facing the first substrate W1.

[0060] The first substrate W1 and the second substrate W2 are bonded together by a first hybrid bonding layer HB1 and a second hybrid bonding layer HB2. The first metal connection structure and the second metal connection structure are bonded together, allowing each pixel electrode 10 formed on the first substrate W1 to be connected to the pixel driving circuit formed on the second substrate W2, thus ensuring circuit control of the pixel electrode 10 in the LCOS device. The material and thickness of the buffer dielectric layer 110 are preferably chosen to enhance light reflection. As an example, the buffer dielectric layer 110 includes a silicon nitride layer 111 and a silicon oxide layer 112, with each pixel electrode 10 formed on the surface of the silicon oxide layer 112. The surface of the pixel electrode 10 that contacts the buffer dielectric layer 110 is a light-reflecting surface.

[0061] In the LCOS device described in this embodiment of the invention, the pixel electrode 10 can be connected to the corresponding pixel driving circuit 210 by bonding the first substrate W1 and the second substrate W2. The surface of the pixel electrode 10 formed on the surface of the buffer dielectric layer 110 and in contact with the buffer dielectric layer 110 (i.e., the bottom surface of the pixel electrode 10) is a light-reflecting surface. The bottom surface of the pixel electrode 10 has a much better defect situation than the top surface, which can ensure that the pixel electrode 10 has better reflective performance and help improve the pixel yield. Furthermore, the first substrate W1 and the second substrate W2 are fabricated separately and then bonded, which helps to control costs and performance. In some embodiments, the first substrate W1 can be pre-screened before bonding with the second substrate W2, which helps to improve the product yield without significantly affecting the manufacturing cost and efficiency.

[0062] It should be noted that the embodiments in this specification are described in a progressive manner, with each part focusing on the differences from the preceding parts, and relevant parts can be understood by referring to them.

[0063] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for manufacturing an LCOS device, characterized in that, include: A first substrate is formed, the first substrate including a first substrate, a buffer dielectric layer formed on the surface of the first substrate, a plurality of pixel electrodes formed on the surface of the buffer dielectric layer, and a first hybrid bonding layer. The first hybrid bonding layer includes a first passivation layer covering the buffer dielectric layer and the plurality of pixel electrodes, and a first metal connection structure formed in the first passivation layer and connecting each of the pixel electrodes. The surface of the pixel electrode that contacts the buffer dielectric layer is a light-reflecting surface. as well as The first substrate is vertically bonded to a second substrate. The second substrate includes a pixel driving circuit formed on the second substrate and a second hybrid bonding layer. The second hybrid bonding layer includes a second passivation layer formed on the second substrate and a second metal connection structure formed in the second passivation layer and connected to the pixel driving circuit. The first hybrid bonding layer and the second hybrid bonding layer are hybrid bonded.

2. The manufacturing method as described in claim 1, characterized in that, Before or after vertically bonding the first substrate to the second substrate, the first substrate is thinned from the side of the first substrate away from the pixel electrode.

3. The manufacturing method as described in claim 2, characterized in that, After thinning the first substrate, the remaining first substrate is patterned to form a metasurface structure.

4. The manufacturing method as described in claim 1, characterized in that, After the first substrate and the second substrate are vertically bonded together, the first substrate is removed.

5. The manufacturing method as described in claim 1, characterized in that, The formation of the first substrate includes: The buffer dielectric layer and the electrode material layer are sequentially stacked on the first substrate; The electrode material layer is patterned to form the plurality of pixel electrodes; A dielectric material is deposited and planarized to form the first passivation layer, the first passivation layer covering the buffer dielectric layer and the plurality of pixel electrodes; and The first metal connection structure is formed in the first passivation layer to obtain the first substrate.

6. The manufacturing method as described in claim 1, characterized in that, Forming the first metal connection structure in the first passivation layer includes: Openings are formed in the first passivation layer to expose the plurality of pixel electrodes; and Metal material is filled into the opening to form a first metal pillar, one end of which is connected to the pixel electrode below, and the other end is flush with the top surface of the first passivation layer.

7. The manufacturing method as described in claim 1, characterized in that, Forming the first metal connection structure in the first passivation layer includes: A groove is formed on the top of the first passivation layer corresponding to each pixel electrode; The first passivation layer is etched from the bottom surface of the groove to form an opening exposing the plurality of pixel electrodes; and Metal material is filled into the opening and the groove to form a metal bonding pad located in the groove and a first metal pillar located in the opening and connected to the pixel electrode. One end of the metal bonding pad is connected to the first metal pillar and the other end is flush with the top surface of the first passivation layer.

8. The manufacturing method as described in claim 1, characterized in that, The buffer medium layer includes at least one nitride layer and at least one oxide layer stacked on the surface of the first substrate.

9. An LCOS device, characterized in that, include: A first substrate includes a buffer dielectric layer, a plurality of pixel electrodes formed on one side surface of the buffer dielectric layer, and a first hybrid bonding layer. The first hybrid bonding layer includes a first passivation layer covering the buffer dielectric layer and the plurality of pixel electrodes, and a first metal connection structure formed in the first passivation layer and connecting each of the pixel electrodes. as well as A second substrate is vertically bonded to the first substrate. The second substrate includes a pixel driving circuit formed on a substrate and a second hybrid bonding layer. The second hybrid bonding layer includes a second passivation layer formed on the substrate and a second metal connection structure formed in the second passivation layer and connected to the pixel driving circuit. The first hybrid bonding layer and the second hybrid bonding layer form a hybrid bond. The surface of the pixel electrode that contacts the buffer dielectric layer is a light-reflecting surface.

10. The LCOS device as claimed in claim 9, characterized in that, The first substrate further includes a first substrate located on the other side of the buffer medium layer.

11. The LCOS device as claimed in claim 10, characterized in that, The first substrate is a patterned metasurface structure.

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