Multilayer multicolor micro-display chip based on color conversion

Abstract

The utility model relates to a multi-layer multi-color micro-display chip based on color conversion, which comprises a driving wafer, a first pixel layer and a second pixel layer, and an anode contact is arranged on the driving wafer; the first pixel layer and the second pixel layer are sequentially stacked on the driving wafer in the Z direction, and excitation pixels are arranged in the first pixel layer; the second pixel layer is internally provided with a color conversion piece and a sub-pixel with a light emitting color different from that of the color conversion piece; the excitation pixels and the sub-pixels each comprise a pixel body, a bonding metal piece is arranged on the side, close to the driving wafer, of each pixel body, and the bonding metal pieces of the sub-pixels in the second pixel layer are electrically connected to the corresponding anode contacts through anode connecting pieces penetrating through the first pixel layer. The bonding metal piece of the sub-pixel in the second pixel layer is provided with a first contact surface, the first contact surface is a non-flat surface, the first contact surface is embedded in the first pixel layer and is in contact with the anode connecting piece, or the anode connecting piece is embedded in the first contact surface. According to the utility model, the reliability of anode current transmission is effectively ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, in particular to a multi-layer multi-color micro-display chip based on color conversion. Background Art

[0002] In the field of LED display, micro-display technology has been widely developed in recent years, especially Micro-LED display technology, which has the advantages of high efficiency, low power consumption, high integration and high stability, and is considered to be one of the most promising next-generation new display and light-emitting devices. Micro-LED display technology has now been widely applied to near-eye display terminal products, including virtual reality (VR), augmented reality (AR), mixed reality (MR), etc. The display area of the existing micro-display chip is usually arranged with a plurality of pixel units arranged in an array. In order to further reduce the horizontal size of the micro-display chip and increase the pixel density, in the prior art, the chip can be set into a vertically stacked multi-layer structure. In this multi-layer structure, adjacent two layers generally need to be bonded through a bonding layer, and the pixel units of the upper layer are connected to the anode connectors of the lower layer through the bonding layer, so as to realize the connection between the pixel units and the anode of the driving wafer through the anode connectors. However, in the existing structure, gaps are easily generated between the bonding layer and the anode connectors in adjacent two layers, resulting in poor contact between the two and affecting electrical transmission, which cannot meet the use requirements. Summary of the Utility Model

[0003] Therefore, the technical problem to be solved by the utility model is to overcome the defect that the contact between the bonding layer and the anode connectors is easily poor and affects electrical transmission in the prior art.

[0004] To solve the above technical problem, the utility model provides a multi-layer multi-color micro-display chip based on color conversion, including,

[0005] A driving wafer, on which anode contacts are arranged;

[0006] A first pixel layer, which is stacked on the driving wafer along the Z direction, and excitation pixels are arranged in the first pixel layer;

[0007] A second pixel layer, which is stacked on the first pixel layer along the Z direction, and color conversion components and sub-pixels with light emission colors different from those of the color conversion components are arranged in the second pixel layer;

[0008] Each of the color conversion components corresponds to an excitation pixel one by one, and the color conversion component is located on the light output path of the corresponding excitation pixel;

[0009] The excitation pixel and the sub-pixel both include a pixel body, and a bonding metal piece is disposed on one side of each pixel body close to the driving wafer. The bonding metal piece of the sub-pixel in the second pixel layer is electrically connected to the corresponding anode contact through an anode connecting piece passing through the first pixel layer. The bonding metal piece of the sub-pixel in the second pixel layer has a first contact surface for contacting the anode connecting piece. The first contact surface is a non-flat surface. The first contact surface is embedded in the first pixel layer and contacts the anode connecting piece, or the anode connecting piece is embedded in the first contact surface.

[0010] In an embodiment of the present invention, the light output color of the color conversion member is red, and the light output color of the excitation pixel is blue.

[0011] In an embodiment of the present invention, sub-pixels are also provided in the first pixel layer. The light output color of the sub-pixels in the first pixel layer is blue, and the light output color of the sub-pixels in the second pixel layer is green.

[0012] In an embodiment of the present invention, an anode hole is formed on the interface between the first pixel layer and the second pixel layer. The anode hole is filled with an anode connecting piece. The top surface of the anode connecting piece filled in the anode hole is lower than the interface to form a recessed portion. An embedding protrusion is formed on the first contact surface. The embedding protrusion of the sub-pixel in the second pixel layer is embedded in the recessed portion of the corresponding anode hole in the first pixel layer to be electrically contacted with the anode connecting piece; or,

[0013] The top surface of the anode connecting piece filled in the anode hole is higher than the interface to form a protruding portion. An embedding recess is formed on the first contact surface. The embedding recess of the sub-pixel in the second pixel layer is engaged with the protruding portion of the corresponding anode connecting piece in the first pixel layer.

[0014] In an embodiment of the present invention, the height of the recessed portion is 10 nm to 300 nm, and the height of the protruding portion is 10 nm to 300 nm.

[0015] In an embodiment of the present invention, the inclination angle of the inner wall of the anode hole with respect to the top surface of the driving wafer is 90° to 120°.

[0016] In an embodiment of the present utility model, a cathode contact is further provided on the driving wafer. The first pixel layer and the second pixel layer both include an insulating body. The pixel bodies in the first pixel layer and the second pixel layer are all located inside the insulating body. An insulating passivation layer is coated outside each pixel body. The bonding metal part is located inside the insulating passivation layer. An opening is formed in the upper part of the insulating passivation layer. A common cathode layer is coated outside the insulating passivation layer. The pixel body is electrically connected to the common cathode layer through the opening, and the common cathode layer is used to be electrically connected to the cathode contact.

[0017] In an embodiment of the present utility model, each pixel body includes a P-type semiconductor layer, an active layer, and an N-type semiconductor layer which are sequentially arranged along the Z direction. The bonding metal part is provided on one side of the P-type semiconductor layer close to the driving wafer, and the N-type semiconductor layer is electrically connected to the common cathode layer through the opening.

[0018] In an embodiment of the present utility model, a cathode hole is formed on the interface between the first pixel layer and the second pixel layer. The cathode hole is filled with a cathode connecting piece, and the cathode connecting pieces are all electrically connected to the cathode contact. The common cathode layer in the second pixel layer is electrically connected to the cathode contact through the cathode connecting piece in the first pixel layer.

[0019] In an embodiment of the present utility model, filling holes are provided in the second pixel layer, and each filling hole is filled with the color conversion piece.

[0020] In an embodiment of the present utility model, the length of the filling hole along the X direction is not less than the maximum length of the excitation pixel in the X direction, and the X direction is perpendicular to the Z direction.

[0021] In an embodiment of the present utility model, an isolation layer is formed on the inner wall of the filling hole, and the isolation layer is a metal reflection layer or an absorption layer.

[0022] In an embodiment of the present utility model, the pixel body is trapezoidal or cylindrical.

[0023] In an embodiment of the present utility model, at least one lens is connected to the upper part of the second pixel layer. The sub-pixels and the color conversion pieces respectively correspond to different lenses, or all the multiple sub-pixels and the color conversion pieces commonly correspond to the same lens.

[0024] The above technical solutions of the present utility model have the following advantages compared with the prior art:

[0025] The multi-layer multi-color microdisplay chip based on color conversion according to the present utility model enables the bonding metal part and the anode connecting part to be in full contact through an interlocking manner, thereby effectively ensuring the reliability of anode current transmission; and also effectively ensuring the connection strength between the bonding metal part and the anode connecting part. Description of the Drawings

[0026] In order to make the content of the present utility model easier to be clearly understood, the following further describes the present utility model in detail according to the specific embodiments of the present utility model in conjunction with the drawings.

[0027] Figure 1 It is a comparison schematic diagram of trapezoidal pixels and hemispherical pixels;

[0028] Figure 2 It is the internal structure diagram of the first multi-layer multi-color microdisplay chip based on color conversion of the present utility model;

[0029] Figure 3 It is Figure 2 The internal enlarged schematic diagram at U in

[0030] Figure 4 It is Figure 2 The structural schematic diagram of the first pixel layer in

[0031] Figure 5 It is the internal structure diagram of the second microdisplay chip of the present utility model;

[0032] Figure 6 It is Figure 5 The internal enlarged schematic diagram at V in

[0033] Figure 7 It is Figure 5 The structural schematic diagram of the first pixel layer in

[0034] Figure 8 It is the internal structure diagram of the third microdisplay chip of the present utility model;

[0035] Figure 9 It is the partial preparation flow chart of the chip of the present utility model;

[0036] Figure 10 It is Figure 8 The preparation flow chart of the structure shown;

[0037] Explanation of the reference numerals in the drawings of the specification:

[0038] 10. Driving wafer; 101. Anode contact; 102. Cathode contact;

[0039] 20. Sub-pixel; 201. Pixel main body; 2011. P-type ohmic contact layer; 2012. P-type semiconductor layer; 2013. Active layer; 2014. N-type semiconductor layer; 2015. N-type ohmic contact layer;

[0040] 30. First pixel layer; 301. Insulating body; 302. Bonding layer; 3021. Bonding metal part; 30211. First contact surface; 30212. Embedded protrusion; 30213. Embedded depression; 303. Insulating passivation layer; 3031. Opening; 304. Common cathode layer; 305. Anode hole; 3051. Depressed part; 306. Anode connecting part; 3061. Protruding part; 307. Cathode hole; 308. Cathode connecting part;

[0041] 40. Second pixel layer; 401. Filling hole; 402. Isolation layer;

[0042] 50. Interface;

[0043] 60. Excitation pixel;

[0044] 70. Color conversion part;

[0045] 80. Compound semiconductor; 801. Substrate;

[0046] 90. Lens. Detailed implementation manners

[0047] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the exemplified embodiments are not used as a limitation to the present invention. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restricts the present disclosure, its application or use.

[0048] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "vertical", "upper", "lower", "top", "side", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present specification 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 thus cannot be understood as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0049] The following will be combined with Figures 1 - 10 to further describe the structure of the color conversion-based multi-layer and multi-color microdisplay chip of this embodiment.

[0050] It should be noted that for convenience of description, in the present utility model, the microdisplay chip has mutually perpendicular Z and X directions, where the Z direction is generally the direction away from the driving wafer. In the present utility model, "up" and "down" are relative in the Z direction. Similarly, "top", "bottom" or "high", "low" are also relative in the Z direction.

[0051] Embodiment

[0052] Referring to Figures 2 - 4 , this embodiment discloses a color conversion-based multi-layer and multi-color microdisplay chip, including a driving wafer 10, a first pixel layer 30 and a second pixel layer 40; the driving wafer 10 can adopt a CMOS driving wafer 10 for controlling sub-pixels 20 and excitation pixels 60 in the pixel layer to emit light;

[0053] Wherein, an anode contact 101 is provided on the driving wafer 10;

[0054] The first pixel layer 30 is stacked on the driving wafer 10 along the Z direction, and excitation pixels 60 are provided in the first pixel layer 30;

[0055] The second pixel layer 40 is stacked on the first pixel layer 30 along the Z direction, and color conversion components 70 and sub-pixels 20 with different light-emitting colors from the light-emitting color of the color conversion components 70 are provided in the second pixel layer 40;

[0056] Each color conversion component 70 corresponds to an excitation pixel 60 one by one, and the color conversion component 70 is located on the light-emitting path of the corresponding excitation pixel 60 to excite the color conversion component 70 to emit light of a corresponding color; when the light emitted by the excitation pixel 60 irradiates the corresponding color conversion component 70, the color conversion component 70 will be excited to emit a certain color of light;

[0057] Both the excitation pixel 60 and the sub-pixel 20 include a pixel body 201, and a bonding metal part 3021 is provided on one side of each pixel body 201 close to the driving wafer 10. The bonding metal part 3021 of the sub-pixel 20 in the second pixel layer 40 is electrically connected to the corresponding anode contact 101 through an anode connecting part 306 passing through the first pixel layer 30 to achieve anode connection;

[0058] The bonding metal part 3021 of the sub-pixel 20 in the second pixel layer 40 has a first contact surface 30211, and the first contact surface 30211 is used to contact the anode connecting part 306. The first contact surface 30211 is a non-flat surface. As Figure 2 shown, the first contact surface 30211 is embedded in the first pixel layer 30 and contacts the anode connecting part 306, or, asFigure 5 As shown, the anode connection member 306 is embedded in the first contact surface 30211.

[0059] Among them, the color conversion member 70 can be made of a quantum dot material or a phosphor material, so as to be excited by external light to undergo color conversion and emit light of a certain specific color.

[0060] In the above structure, when the bonding metal member 3021 of the sub-pixel 20 in the second pixel layer 40 is connected to the anode connection member 306 of the underlying first pixel layer 30, the contact surface between the bonding metal member 3021 and the anode connection member 306 is a non-flat surface, so that the first contact surface 30211 is embedded in the first pixel layer 30 and contacts the anode connection member 306, or the anode connection member 306 is embedded in the first contact surface 30211. This form of fitting structure can effectively prevent the occurrence of bonding gaps or voids between the bonding metal member 3021 and the anode connection member 306, enabling the bonding metal member 3021 and the anode connection member 306 to be in full contact, thereby effectively ensuring the reliability of anode current transmission; in addition, adopting the above mutually fitting structure also effectively ensures the connection strength between the bonding metal member 3021 and the anode connection member 306, and is also more conducive to alignment and positioning.

[0061] Among them, the bonding metal member 3021 can correspond one-to-one with the anode contact 101, or multiple anode contacts 101 can correspond to one bonding metal member 3021.

[0062] In some embodiments, the light-emitting color of the color conversion member 70 is red, and the light-emitting color of the excitation pixel 60 is blue.

[0063] It should be noted that the light-emitting wavelength of the excitation pixel 60 is shorter than the red light wavelength, so as to use light with a shorter wavelength to excite the color conversion member 70 to undergo color conversion and emit red light. The color conversion member 70 is made of a quantum dot material or a red phosphor material.

[0064] Furthermore, as Figure 2 shown, sub-pixels 20 are also provided in the first pixel layer 30. The light-emitting color of the sub-pixels 20 in the first pixel layer 30 is blue, and the light-emitting color of the sub-pixels 20 in the second pixel layer 40 is green.

[0065] The blue light emitted by the sub-pixels 20 in the first pixel layer 30 is emitted through the second pixel layer 40, the green light emitted by the sub-pixels 20 in the second pixel layer 40 is emitted through the second pixel layer 40, and the red light emitted by the color conversion member 70 under excitation is also emitted through the second pixel layer 40. Then, the light finally emitted through the second pixel layer 40 includes: green light, blue light, and red light, thus achieving a three-color configuration.

[0066] Specifically, as Figure 2 and Figure 5As shown, two excitation pixels 60 and one sub-pixel 20 with a blue light-emitting color are provided in the first pixel layer 30, and two color conversion components 70 and one sub-pixel 20 with a green light-emitting color are correspondingly provided in the second pixel layer 40.

[0067] In some embodiments, the red color conversion component 70 can be made of a quantum dot material, such as indium phosphide (InP); or it can be made of a phosphor material, such as fluoride-based phosphor-KSF red phosphor

[0068] (K2SiF6:Mn4+), or nitride Eu2+-doped CaAlSiN3-based red phosphor, etc.

[0069] The above-mentioned sub-pixel 20 and excitation pixel 60 are both electrically connected to the driving wafer 10, and the driving wafer 10 has a driving circuit to control the light emission of the sub-pixel 20 and excitation pixel 60 by using the driving circuit.

[0070] In some embodiments, the projections of the excitation pixel 60 and the color conversion component 70 on the driving wafer 10 overlap each other, and they can be coaxially arranged, so that the light emitted by the excitation pixel 60 can reach the color conversion component 70 well, thereby exciting the color conversion component 70 to emit light of a specific color.

[0071] In some embodiments, an anode hole 305 is formed on the interface 50 between the first pixel layer 30 and the second pixel layer 40, and the anode hole 305 is filled with an anode connector 306, such as Figures 2 - 4 As shown, the top surface of the anode connector 306 filled in the anode hole 305 is lower than the interface 50 to form a recess 3051. An embedding protrusion 30212 is formed on the first contact surface 30211. The embedding protrusion 30212 of the sub-pixel 20 in the second pixel layer 40 is embedded in the recess 3051 of the corresponding anode hole 305 in the first pixel layer 30 to be in electrical contact with the anode connector 306; or,

[0072] As Figures 5 - 7 shown, the top surface of the anode connector 306 filled in the anode hole 305 is higher than the interface 50 to form a protrusion 3061. An embedding recess 30213 is formed on the first contact surface 30211. The embedding recess 30213 of the sub-pixel in the second pixel layer 40 is fitted with the protrusion 3061 of the corresponding anode connector 306 in the first pixel layer 30. This method is more convenient for processing. Through the above-mentioned convex-concave fitting method, good electrical transmission effects can be effectively guaranteed.

[0073] In addition, compared with making the interface between adjacent two pixel layers into a completely flat structure, the above-mentioned interface with convex-concave characteristics is easier to process, simplifies the processing technology, and is more conducive to the mass production of products.

[0074] In some embodiments, such as Figure 4 shown, the height h1 of the recess 3051 is 10 nm to 300 nm. As Figure 7 shown, the height h2 of the protrusion 3061 is 10 nm to 300 nm. To better avoid bonding voids and ensure the electrical transmission effect. The above heights should not be too large, as too large a height is likely to increase the process difficulty, and if the height is too small, the electrical transmission effect cannot be better ensured.

[0075] In some embodiments, the top length (in the X direction) of the anode hole 305 is greater than the bottom length.

[0076] In some embodiments, such as Figure 4 shown, the inclination angle φ of the inner wall of the anode hole 305 relative to the top surface of the driving wafer 10 is 90° to 120°.

[0077] Furthermore, the anode hole 305 can be trapezoidal; it can also be Y-shaped.

[0078] In some embodiments, a cathode contact 102 is further provided on the driving wafer 10. The first pixel layer 30 and the second pixel layer 40 both include an insulating body 301. The pixel bodies 201 in the first pixel layer 30 are all coated inside the insulating body 301 of this layer. Similarly, the pixel bodies 201 in the second pixel layer 40 are all coated inside the insulating body 301 of this layer;

[0079] Among them, an insulating passivation layer 303 is coated outside each pixel body 201. The bonding metal part 3021 is located inside the insulating passivation layer 303. The upper part of the insulating passivation layer 303 has an opening 3031. The outside of the insulating passivation layer 303 is coated with a common cathode layer 304. The pixel body 201 is electrically connected to the common cathode layer 304 through the opening 3031. The common cathode layer 304 is used to be electrically connected to the cathode contact 102.

[0080] Among them, each pixel body 201 includes a P-type semiconductor layer 2012, an active layer 2013, and an N-type semiconductor layer 2014 arranged in sequence along the Z direction. The active layer 2013 is used to emit light. The P-type semiconductor layer 2012 is used to connect to the anode of the driving wafer 10 to achieve anode connection, and the N-type semiconductor layer 2014 is used to connect to the cathode of the driving wafer 10 to achieve cathode connection.

[0081] Further, bonding metal parts 3021 are disposed on the side of the P-type semiconductor layer 2012 close to the driving wafer 10, and a P-type ohmic contact layer 2011 is disposed between the P-type semiconductor layer 2012 and the bonding metal parts 3021, so as to achieve ohmic contact between the P-type semiconductor layer 2012 and the bonding metal parts 3021. Eventually, the P-type semiconductor layer 2012 is electrically connected to the corresponding anode contact 101 through the bonding metal parts 3021 to achieve anode connection; the N-type semiconductor layer is exposed at the opening 3031, and the exposed part is electrically connected to the common cathode layer 304, and the common cathode layer 304 is used to connect to the cathode contact 102 of the driving wafer 10 to achieve cathode connection. The insulating passivation layer 303 is used to insulate and isolate the N-type semiconductor layer 2014 and the P-type semiconductor layer 2012 in the pixel main body 201 to avoid short circuit.

[0082] Further, the above-mentioned anode hole 305 is formed in the insulating body 301 of the first pixel layer 30.

[0083] In some embodiments, as Figure 4 shown, the height D of the pixel main body 201 in the Z direction is 0.3 um to 5 um; preferably, D is 0.3 um to 1.5 um; wherein, the height of the pixel main body 201 is the distance between its P-type semiconductor layer 2012 and N-type semiconductor layer 2014 (including the thicknesses of the P-type semiconductor layer 2012 and N-type semiconductor layer 2014 themselves).

[0084] Further, the inclination angle θ of the side wall of the pixel main body 201 relative to the driving wafer 10 is 45° to 135°; it can be understood that the side wall of the pixel main body 201 here refers to the wall surface between the top surface and the bottom surface of the pixel main body 201;

[0085] The above inclination angle can reduce total reflection and is more conducive to light extraction. Beyond this range, the light extraction efficiency will be reduced; in addition, due to limited horizontal space, a certain space needs to be reserved for subsequent processes. When the inclination angle is too small, the bottom surface of the pixel occupies too much horizontal space, which will increase the difficulty of pixel pitch arrangement.

[0086] Preferably, the inclination angle θ of the side wall of the pixel main body 201 relative to the driving wafer 10 is 75° to 105°, which has the best light extraction efficiency and the best pixel pitch design.

[0087] In some embodiments, the thickness of the P-type ohmic contact layer 2011 is 10 nm to 300 nm, and its material can be a transparent conductive film such as indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), etc., or a metal alloy film such as AuBe, AnZn, etc.

[0088] In some embodiments, the thickness of the insulating and passivating layer 303 is 30 nm to 500 nm to preferably ensure the insulating and passivating capabilities.

[0089] In some embodiments, the thickness of the common cathode layer 304 is 50 nm to 500 nm to increase its transmittance as much as possible while ensuring the current spreading ability. The thicker the common cathode layer 304 is, the better the current spreading is, but the lower the transmittance is, which will cause greater light loss and also increase the processing difficulty. If the thickness is too thin, the metal current spreading ability will be affected.

[0090] In one of the embodiments, the length of the top end of the anode connector 306 in the X direction is greater than that of the bottom end, that is, it has a structure form that is wider at the top and narrower at the bottom. When the length of the bottom end is the same, compared with the structure that is narrower at the top and wider at the bottom, this shape of the structure can obtain a thicker anode connector, thereby enhancing the anode electrical transmission ability. Among them, the X direction and the Z direction are perpendicular to each other.

[0091] In some embodiments, cathode holes 307 are formed on the interface 50 between the first pixel layer 30 and the second pixel layer 40. The cathode holes 307 are filled with cathode connectors 308, and the cathode connectors 308 are all electrically connected to the cathode contacts 102. The common cathode layer 304 in the second pixel layer 40 is electrically connected to the cathode contacts 102 through the cathode connectors 308 and the cathode contacts 102 in the first pixel layer 30.

[0092] The common cathode layer 304 of the first pixel layer 30 can be directly electrically connected to the cathode contacts 102.

[0093] Further, as Figure 4 and Figure 7 shown, cathode holes 307 are also formed on the interface 50 between the first pixel layer 30 and the second pixel layer 40. The top surface of the cathode connector 308 filled in the cathode holes 307 is lower than the interface 50 to form a recessed portion 3051, or the top surface of the cathode connector 308 filled in the cathode holes 307 is higher than the interface 50 to form a protruding portion 3061. This is similar to the setting method of the anode connector 306 and will not be elaborated here.

[0094] In some embodiments, filling holes 401 are provided in the second pixel layer 40, and each filling hole 401 is filled with a color conversion member 70.

[0095] Among them, the filling holes 401 are formed in the insulating body 301 of the second pixel layer 40.

[0096] Further, as Figure 2 shown, the inner wall of the filling hole 401 is inclined with respect to the driving wafer 10, and the inclination angle C is 60° to 90° to be more convenient for etching and also ensure the filling effect.

[0097] In some embodiments, the length Ls of the filling hole 401 in the X direction is not less than the maximum length of the excitation pixel 60 in the X direction, and the X direction is perpendicular to the Z direction. In this way, a good optical channel can be provided for the underlying excitation pixel 60 and optical crosstalk is not likely to occur, thus ensuring the color conversion effect to the greatest extent.

[0098] In some embodiments, an isolation layer 402 is formed on the inner wall of the filling hole 401, and the isolation layer 402 is used to shield the light interference from the pixels below the non-filling space, so that the color conversion element 70 inside the filling hole 401 can have a better color conversion effect.

[0099] Among them, the isolation layer 402 is a metal reflection layer or a light absorption layer.

[0100] The material of the metal reflection layer can be one or more of metals Al, Ti, Pt, Au, Cr, and Ni to shield light interference through metal reflection; the material of the light absorption layer can be light-absorbing materials such as carbon film, black glue, and polysilicon to shield light interference through light absorption.

[0101] Furthermore, the thickness of the isolation layer 402 is 50 nm to 2 μm. If the thickness is too thin, it is easy to leak electricity, and if it is too thick, the cost will increase.

[0102] Specifically, it can be carried out according to the thickness required to achieve light interference shielding for different materials. For example, Al ≥ 50 nm and black glue ≥ 1 μm.

[0103] In some embodiments, the pixel body 201 is trapezoidal or cylindrical.

[0104] As Figure 2 shown, the pixel body 201 is trapezoidal or cylindrical. Compared with pixels having a hemispherical structure or a semi-ellipsoidal structure, the trapezoidal or cylindrical pixels can effectively increase the light-emitting area of the pixels, thereby increasing the light-emitting intensity; generally, there is an active layer in the pixel to emit light. As Figure 1 can be seen, when the bottom size of the pixels is the same, the area of the active layer 2013 in the trapezoidal pixel (the entire shaded part) is larger than the area of the active layer in the hemispherical pixel (the shaded part inside the hemisphere), thereby effectively increasing the light-emitting intensity. Similarly, compared with the hemispherical pixel, the cylindrical pixel can also increase the area of the active layer, thereby effectively increasing the light-emitting intensity.

[0105] In some embodiments, as Figure 8 shown, at least one lens 90 is connected to the upper part of the second pixel layer 40, and the sub-pixels 20 and the color conversion elements 70 respectively correspond to different lenses to better collimate the emitted light of each sub-pixel 20 and further reduce the light interference between the pixels; alternatively, all the multiple sub-pixels 20 and the color conversion elements 70 commonly correspond to the same lens.

[0106] This embodiment also discloses a method for manufacturing the above-mentioned microdisplay chip, including the following steps:

[0107] Step M1: Prepare a driving wafer 10, on which an anode contact 101 is provided;

[0108] Step M2: Stack a first pixel layer 30 and a second pixel layer 40 on the driving wafer 10 in the Z direction in sequence, such that an excitation pixel 60 is provided in the first pixel layer 30, a color conversion element 70 and a sub-pixel 20 with a light output color different from that of the color conversion element 70 are provided in the second pixel layer 40, each color conversion element 70 corresponds to an excitation pixel 60 one by one, and each color conversion element 70 is located on the light output path of the corresponding excitation pixel 60; wherein, both the excitation pixel 60 and the sub-pixel 20 include a pixel body 201, a bonding metal part 3021 is provided on one side of each pixel body 201 close to the driving wafer 10, and the bonding metal part 3021 of the sub-pixel 20 in the second pixel layer 40 is electrically connected to the corresponding anode contact 101 through an anode connecting part 306 passing through the first pixel layer 30. The bonding metal part 3021 has a first contact surface 30211 for contacting the anode connecting part 306, the first contact surface 30211 is a non-flat surface, the first contact surface 30211 is embedded in the first pixel layer 30 and contacts the anode connecting part 306, or the anode connecting part 306 is embedded in the first contact surface 30211.

[0109] In one implementation, after step M2, as Figure 10 shown in the f stage, a dielectric layer is further deposited on the upper part of the second pixel layer 40, and the dielectric layer is patterned and etched to form a lens 90, such that each sub-pixel 20 and color conversion element 70 respectively correspond to different lenses, or all the multiple sub-pixels 20 and color conversion elements 7 together correspond to the same lens;

[0110] In some implementations, step M2 includes:

[0111] Step M21: As Figure 9 shown, bond a compound semiconductor 80 on the driving wafer 10; for example, the compound semiconductor 80 can be bonded on the driving wafer 10 through a bonding layer 302;

[0112] The above-mentioned compound semiconductor 80 includes a P-type ohmic contact layer 2011, a P-type semiconductor layer 2012, an active layer 2013, an N-type semiconductor layer 2014 and a substrate 801 arranged in sequence in a direction away from the driving wafer 10. After bonding the compound semiconductor 80 on the driving wafer 10, the substrate 801 needs to be removed to expose the N-type semiconductor layer 2014; after removing the substrate 801, an N-type ohmic contact layer 2015 can also be provided on the N-type semiconductor layer 20142014;

[0113] Further, the thickness of the N-type ohmic contact layer 2015 is 10 nm to 300 nm, and its material may be a transparent conductive thin film such as indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), etc., or a metal alloy thin film such as gold germanium alloy (AuGe), gold nickel alloy (AuNi), etc.

[0114] Preferably, the thickness of the N-type ohmic contact layer 2015 is 10 nm to 100 nm to ensure ohmic contact while also having a high transmittance, thereby reducing light loss.

[0115] Step M22: Pattern-etch the compound semiconductor 80 to obtain at least one group of pixels. In this group of pixels, there are excitation pixels 60 and sub-pixels 20 with a blue light-emitting color. Both the excitation pixels 60 and the sub-pixels 20 with a blue light-emitting color include pixel bodies 201, and each pixel body 201 is electrically connected to the corresponding anode contact 101 through the corresponding bonding metal part 3021; each pixel body 201 corresponds to one bonding metal part 3021; wherein, the bonding metal part 3021 can be obtained by etching the bonding layer 302.

[0116] Step M23: Deposit an insulating passivation layer 303 outside the pixel body 201, and set an opening 3031 on the upper part of the insulating passivation layer 303 to expose the N-type semiconductor layer 2014 or the N-type ohmic contact layer 2015 of the pixel body 201.

[0117] Step M24: Deposit a common cathode layer 304 outside the insulating passivation layer 303, so that the pixel body 201 is electrically connected to the common cathode layer 304 through the opening 3031, and the common cathode layer 304 is used to be electrically connected to the cathode contact 102.

[0118] That is, the N-type semiconductor layer 20, of the pixel body 201 is electrically connected to the cathode contact 102 through the common cathode layer 304 to achieve cathode connection.

[0119] Among them, only one cathode contact 102 can be provided on the driving wafer 10, or the number of cathode contacts 102 can be determined according to needs.

[0120] Step M25: Fill an insulating body 301 outside the common cathode layer 304, so that all pixel bodies 201 are located inside the insulating body 301, and an anode connecting part 306 is prepared in the first pixel layer 30, thereby obtaining the first pixel layer 30 as shown in Figure 10 stage c.

[0121] It can be understood that the insulating passivation layer 303 and the common cathode layer 304 outside the pixel body 201 are also located inside the insulating body 301.

[0122] Step M26: Bond another compound semiconductor 80 on top of the first pixel layer 30, perform patterning etching on the compound semiconductor 80 to obtain a sub-pixel 20 - green sub-pixel with a green light-emitting color. The sub-pixel with a green light-emitting color also includes a pixel body 201. The bonding metal part 3021 of the green sub-pixel in the second pixel layer 40 is electrically connected to the corresponding anode contact 101 by the anode connecting part 306 passing through the first pixel layer 30. The bonding metal part 3021 has a first contact surface 30211 for contacting the anode connecting part 306. The first contact surface 30211 is a non-flat surface. The first contact surface 30211 is embedded in the first pixel layer 30 and contacts the anode connecting part 306, or the anode connecting part 306 is embedded in the first contact surface 30211; then repeat steps M23 - M24;

[0123] Step M27: Fill an insulating body 301 outside the common cathode layer 304 so that the pixel bodies 201 are all located inside the insulating body 301, and as Figure 10 shown in stage d in Figure 10 , set a filling hole 401 on the insulating body 301, and fill a color conversion material in the filling hole 401 to form a color conversion part 70. As

[0124] shown in stage e in

[0125] shown in

[0126] thereby completing the preparation of the second pixel layer 40.

[0127] It can be understood that the position of the filling hole 401 should be on the light-emitting path of the excitation pixel 60 so that the light emitted by the excitation pixel 60 can pass through the color conversion part 70 in the hole, thereby exciting the red light color conversion part 70 to emit color conversion and generate red light.

[0128] It can be understood that since the light-emitting colors of the sub-pixels 20 in the two pixel layers are different, the materials of the compound semiconductors 80 used in the preparation of the two pixel layers are also different, so that the light-emitting colors of the compound semiconductors 80 used are different.

[0129] In one embodiment, the common cathode layer 304 includes one or more of indium tin oxide (ITO), indium zinc oxide (IZO), aluminum-doped zinc oxide (AZO), aluminum-doped indium tin oxide, silver-doped indium tin oxide, and gold-doped indium tin oxide;

[0130] In one embodiment, the material of the anode connector 306 can be one or more of aluminum, copper, and tungsten.

[0131] Furthermore, the material of the cathode connector 308 can be the same as that of the anode connector 306, as long as it is a conductive material.

[0132] In one embodiment, the material of the bonding metal part 3021 can be one of Al, Au, and Cu, or a laminated structure of Ni, Au, Cu, etc. and Sn, or a bonded laminate of Au and In, Ge, or a bonded laminate of Au and Si.

[0133] Furthermore, the above bonding metal part 3021 can adopt the following structural form: Cr2nm / Pt50nm / Ti 10nm / Pt50nm / Au100nm / Sn150nm / Au50nm, where Cr is the adhesion layer and Pt / Ti / Pt is the barrier layer.

[0134] In some other embodiments, only the excitation pixels 60 can be provided in the first pixel layer 30. At this time, there are only two colors of light emitted from the entire chip through the second pixel layer 40.

[0135] For example, if the light emission color of the excitation pixels 60 in the first pixel layer 30 is also blue, when the blue light emitted by the laser pixels passes through the corresponding red color conversion component above, it will excite the red color conversion component to emit red light. Then, the light finally emitted from the chip through the second pixel layer 40 is only the red light and the green light emitted by the green sub-pixels. At this time, the chip product is a two-color product.

[0136] In the multi-layer multi-color microdisplay chip of the above embodiment, through the mutually embedded method, the bonding metal part and the anode connector are in full contact, thus effectively ensuring the reliability of the anode current transmission; it also effectively ensures the connection strength between the bonding metal part and the anode connector, and at the same time is more conducive to the alignment and positioning of the two.

[0137] All the above optional technical solutions can be combined arbitrarily to form optional embodiments of the present invention, that is, any number of embodiments can be combined to meet the requirements of different application scenarios, and all are within the protection scope of this application, and will not be elaborated here one by one.

[0138] It should be noted that the above embodiments are merely examples for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A multi-layer and multi-color microdisplay chip based on color conversion, characterized in that: Including, a driving wafer, on which an anode contact is provided; a first pixel layer, which is stacked on the driving wafer along the Z direction, and excitation pixels are provided in the first pixel layer; a second pixel layer, which is stacked on the first pixel layer along the Z direction, and color conversion elements and sub-pixels with light emission colors different from those of the color conversion elements are provided in the second pixel layer; each of the color conversion elements corresponds to an excitation pixel one by one, and the color conversion element is located on the light emission path of the corresponding excitation pixel; both the excitation pixel and the sub-pixel include a pixel body, and a bonding metal part is provided on one side of each pixel body close to the driving wafer. The bonding metal part of the sub-pixel in the second pixel layer is electrically connected to the corresponding anode contact by an anode connecting part passing through the first pixel layer. The bonding metal part of the sub-pixel in the second pixel layer has a first contact surface for contacting the anode connecting part. The first contact surface is a non-flat surface. The first contact surface is embedded in the first pixel layer and contacts the anode connecting part, or the anode connecting part is embedded in the first contact surface.

2. The multi-layer and multi-color microdisplay chip based on color conversion according to claim 1, wherein: The light emission color of the color conversion element is red, and the light emission color of the excitation pixel is blue.

3. The multi-layer and multi-color microdisplay chip based on color conversion according to claim 2, wherein: Sub-pixels are also provided in the first pixel layer. The light emission color of the sub-pixel in the first pixel layer is blue, and the light emission color of the sub-pixel in the second pixel layer is green.

4. The multi-layer and multi-color microdisplay chip based on color conversion according to claim 1, characterized in that: An anode hole is formed on the interface between the first pixel layer and the second pixel layer. The anode hole is filled with an anode connecting part. The top surface of the anode connecting part filled in the anode hole is lower than the interface to form a recessed part. An embedding protrusion is formed on the first contact surface. The embedding protrusion of the sub-pixel in the second pixel layer is embedded in the recessed part of the corresponding anode hole in the first pixel layer to be electrically connected to the anode connecting part; or, the top surface of the anode connecting part filled in the anode hole is higher than the interface to form a protruding part. An embedding recess is formed on the first contact surface. The embedding recess of the sub-pixel in the second pixel layer is engaged with the protruding part of the corresponding anode connecting part in the first pixel layer.

5. The multi-layer and multi-color microdisplay chip based on color conversion according to claim 4, wherein: The height of the recessed part is 10nm - 300nm, and the height of the protruding part is 10nm - 300nm.

6. The multi-layer and multi-color microdisplay chip based on color conversion according to claim 4, characterized in that: The inclination angle of the inner wall of the anode hole relative to the top surface of the driving wafer is 90° - 120°.

7. The multi-layer and multi-color microdisplay chip based on color conversion according to claim 1, characterized in that: A cathode contact is also provided on the driving wafer. Both the first pixel layer and the second pixel layer include an insulating body. The pixel bodies in the first pixel layer and the second pixel layer are both located inside the insulating body. Each pixel body is coated with an insulating passivation layer on the outside. The bonding metal part is located inside the insulating passivation layer. The upper part of the insulating passivation layer has an opening. The outside of the insulating passivation layer is coated with a common cathode layer. The pixel body is electrically connected to the common cathode layer through the opening. The common cathode layer is used to be electrically connected to the cathode contact.

8. The multi-layer and multi-color microdisplay chip based on color conversion according to claim 7, wherein: Each of the pixel bodies includes a P-type semiconductor layer, an active layer, and an N-type semiconductor layer arranged in sequence along the Z direction. The bonding metal pieces are provided on one side of the P-type semiconductor layer close to the driving wafer. The N-type semiconductor layer is electrically connected to the common cathode layer through the opening.

9. The multi-layer and multi-color microdisplay chip based on color conversion according to claim 7, wherein: Cathode holes are formed on the interface between the first pixel layer and the second pixel layer. The cathode holes are filled with cathode connectors, and the cathode connectors are electrically connected to the cathode contacts. The common cathode layer in the second pixel layer is electrically connected to the cathode contacts through the cathode connectors in the first pixel layer.

10. The multi-layer and multi-color microdisplay chip based on color conversion according to claim 1, characterized in that: Filling holes are provided in the second pixel layer, and each of the filling holes is filled with the color conversion member.

11. The multi-layer and multi-color microdisplay chip based on color conversion according to claim 10, wherein: The length of the filling hole in the X direction is not less than the maximum length of the excitation pixel in the X direction, and the X direction is perpendicular to the Z direction.

12. The multi-layer multi-color microdisplay chip based on color conversion according to claim 10, wherein: An isolation layer is formed on the inner wall of the filling hole, and the isolation layer is a metal reflection layer or a light absorption layer.

13. The multi-layer and multi-color microdisplay chip based on color conversion according to claim 1, characterized in that: The pixel body is trapezoidal or cylindrical.

14. The multi-layer and multi-color micro-display chip based on color conversion according to claim 1, wherein: At least one lens is connected to the upper part of the second pixel layer, and the sub-pixels and the color conversion members respectively correspond to different lenses, or all the multiple sub-pixels and the color conversion members commonly correspond to the same lens.

Images