Micro-LED display based on hybrid bonding process and preparation method thereof

Abstract

The invention discloses a Micro-LED display based on a hybrid bonding process and a preparation method thereof, and relates to the technical field of display preparation. The preparation method comprises the following steps: preparing a substrate of the Micro-LED display by using a silicon substrate and a polymer material; and carrying out hybrid bonding on the substrate and the Micro-LED chip by using a flip-chip bonding machine and applying pressure and temperature to obtain the Micro-LED display. The performance and reliability of the Micro-LED display device can be improved by introducing the polymer material.

Description

Technical Field

[0001] The present invention relates to the technical field of display preparation, and in particular to a Micro-LED display based on a hybrid bonding process and a preparation method thereof. Background Art

[0002] With the rapid progress of display technology, Micro-LED technology, as the future star in the display field, is gradually occupying the forefront of research and application with its excellent performance characteristics, including high brightness, low power consumption, ultra-long life and unparalleled high contrast. However, the pursuit of high performance of Micro-LED display devices has put forward unprecedented high standards for its manufacturing process, especially in the precision bonding link between the chip and the substrate. How to effectively deal with the stress concentration problem caused by the difference in the thermal expansion coefficient of the material, so as to ensure the structural integrity and long-term reliability of the device, has become a technical barrier that needs to be overcome.

[0003] At present, the bonding technologies of Micro-LED display devices mainly include traditional eutectic bonding, metal welding and emerging laser mass bonding. Although these methods have their own advantages, such as eutectic bonding can achieve strong bonding strength, but the accompanying thermal stress mismatch problem limits its long-term stability; although metal welding can reduce thermal stress, its high cost and complex process flow limit its wide application; laser mass bonding is known for its high precision and high efficiency, but the demand for high-precision equipment and high cost investment also pose challenges.

[0004] Polymer materials, such as benzocyclobutene (BCB) and polyimide (PI), have been widely used in the field of microelectronic packaging due to their good thermal and chemical stability. These materials can provide additional physical connections for device connections through bonding, providing new ideas for the bonding process of Micro-LED display devices. However, the current application of polymer materials in the hybrid bonding process of Micro-LED display devices still faces problems such as uneven interfaces and insufficient bonding strength, which requires further technological innovation and optimization. Summary of the invention

[0005] The purpose of the present invention is to provide a Micro-LED display based on a hybrid bonding process and a preparation method thereof, which can improve the performance and reliability of the Micro-LED display device by introducing polymer materials.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A Micro-LED display based on a hybrid bonding process, comprising:

[0008] A substrate for a Micro-LED display is prepared using a silicon substrate and a polymer material;

[0009] A flip-chip bonding machine is used to perform hybrid bonding between the substrate and the Micro-LED chip by applying pressure and temperature to obtain a Micro-LED display.

[0010] Optionally, the preparation process of the substrate of the Micro-LED display includes:

[0011] Step 101: Spin-coating a negative photoresist on a silicon substrate, and exposing a pixel region and a cathode strip through a photolithography process;

[0012] Step 102: manufacturing a Ti / Ni / Au common anode and a common cathode by electron beam evaporation;

[0013] Step 103: spin coating a polymer material on the silicon substrate and performing preliminary curing;

[0014] Step 104: Spin-coat a positive photoresist on the basis of the spin-coated polymer material, and perform exposure and development to complete patterning;

[0015] Step 105: completing the patterning of the dielectric layer by dry etching;

[0016] Step 106: using electron beam evaporation to deposit metal indium as bumps;

[0017] Step 107: Use a lift-off process to remove excess metal and photoresist.

[0018] Optionally, the thickness of the Ti / Ni / Au common anode and common cathode is 350 nm.

[0019] Optionally, the polymer material is benzocyclobutene or polyimide.

[0020] The present invention also discloses a Micro-LED display based on a hybrid bonding process, comprising: a substrate prepared based on a polymer material and a Micro-LED chip fixedly connected to the substrate using a hybrid bonding process.

[0021] Optionally, the substrate comprises, from bottom to top, a Si layer, a Ti / Ni / Au layer, a polymer material layer and an indium layer.

[0022] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0023] The present invention discloses a Micro-LED display based on a hybrid bonding process and a preparation method thereof, wherein the preparation method comprises preparing a substrate of the Micro-LED display using a silicon substrate and a polymer material; using a flip-chip bonding machine, and hybrid bonding the substrate with a Micro-LED chip by applying pressure and temperature to obtain a Micro-LED display. The present invention can solve the problems of thermal stress shock and uneven interface in the bonding process of the Micro-LED chip and the substrate in the prior art by introducing polymer materials and using a hybrid bonding process, thereby improving the performance and reliability of the Micro-LED display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 Schematic diagram of the preparation process of the substrate in this embodiment.

[0026] Figure 2 Schematic diagram of the cross-sectional structure of the device after hybrid bonding in this embodiment. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The purpose of the present invention is to provide a Micro-LED display based on a hybrid bonding process and a preparation method thereof, which can improve the performance and reliability of the Micro-LED display device by introducing polymer materials.

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1 As shown, the present invention provides a Micro-LED display based on a hybrid bonding process, comprising:

[0031] Step 100: preparing a substrate for a Micro-LED display using a silicon substrate and a polymer material;

[0032] Step 200: Use a flip-chip bonding machine to perform hybrid bonding between the substrate and the Micro-LED chip by applying pressure and temperature to obtain a Micro-LED display.

[0033] As a specific implementation method, specifically:

[0034] Step 101: Spin-coating a negative photoresist on a silicon substrate, and exposing a pixel region and a cathode strip through a photolithography process;

[0035] Step 102: manufacturing a Ti / Ni / Au common anode and a common cathode with a thickness of 350 nm by electron beam evaporation;

[0036] Step 103: spin coating a polymer material, such as benzocyclobutene (BCB), polyimide (PI), etc., on the silicon substrate, and performing preliminary curing;

[0037] Step 104: Spin-coat a positive photoresist on the basis of the spin-coated polymer material, and perform exposure and development to complete patterning;

[0038] Step 105: completing the patterning of the dielectric layer by dry etching;

[0039] Step 106: Electron beam evaporation of metal indium (In) as bumps;

[0040] Step 107: Lift-off process to remove excess metal and photoresist. The above steps of substrate preparation flow chart is as follows Figure 1 As shown;

[0041] Step 108: Use a flip-chip bonding machine to achieve hybrid bonding of the Micro-LED by applying pressure and temperature. The schematic diagram of the cross-sectional structure of the device after hybrid bonding is as follows: Figure 2 shown.

[0042] Due to the small size of Micro LED, spin coating has several significant advantages over traditional dispensing processes during the preparation process. For example, (1) High efficiency: The main advantage of spin coating is that it takes a short time, usually tens of seconds, which improves production efficiency. (2) The film is uniform and smooth: Spin coating technology can obtain very smooth films and can control the thickness very accurately and repeatedly. This uniformity and smoothness are crucial to the preparation of Micro LED because it ensures uniform light emission and high-quality display of each pixel. (3) Suitable for tiny sizes: Due to the very small size of Micro LED, spin coating technology can better adapt to this tiny preparation environment. Traditional dispensing processes may encounter problems with accuracy and uniformity when dealing with such tiny sizes, while spin coating technology can more accurately control the distribution of glue.

[0043] In addition, this embodiment proposes a hybrid bonding process for Micro-LED display devices based on polymer materials and metal bumps according to the hybrid bonding process steps of spin coating and dry etching, aiming to improve the structural strength and reliability of Micro-LED display devices by increasing bonding strength and reducing thermal stress shock.

[0044] Therefore, this embodiment has the following beneficial effects:

[0045] (1) Enhanced structural strength: Polymer materials have good physical connection properties and can form a stable connection between the Micro-LED chip and the substrate, thus enhancing the structural strength of the device.

[0046] (2) Prolonging service life: Under long-term working conditions, the hybrid bonding process of the present invention can reduce performance degradation caused by thermal stress, reduce the generation of bad pixels, and extend the service life of Micro-LED display devices.

[0047] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0048] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for preparing a Micro-LED display based on a hybrid bonding process, characterized in that: include: A substrate for a Micro-LED display is prepared using a silicon substrate and a polymer material; A flip-chip bonding machine is used to perform hybrid bonding between the substrate and the Micro-LED chip by applying pressure and temperature to obtain a Micro-LED display.

2. The method for preparing a Micro-LED display based on a hybrid bonding process according to claim 1, characterized in that: The preparation process of the substrate of the Micro-LED display includes: Step 101: Spin-coating a negative photoresist on a silicon substrate, and exposing a pixel region and a cathode strip through a photolithography process; Step 102: manufacturing a Ti / Ni / Au common anode and a common cathode by electron beam evaporation; Step 103: spin coating a polymer material on the silicon substrate and performing preliminary curing; Step 104: Spin-coat a positive photoresist on the basis of the spin-coated polymer material, and perform exposure and development to complete patterning; Step 105: completing the patterning of the dielectric layer by dry etching; Step 106: using electron beam evaporation to deposit metal indium as bumps; Step 107: Use a lift-off process to remove excess metal and photoresist.

3. The method for preparing a Micro-LED display based on a hybrid bonding process according to claim 2, characterized in that: The thickness of the Ti / Ni / Au common anode and common cathode is 350nm.

4. The method for preparing a Micro-LED display based on a hybrid bonding process according to claim 2, characterized in that: The polymer material is benzocyclobutene or polyimide.

5. A Micro-LED display based on a hybrid bonding process, characterized in that: include: A substrate made of polymer material and a Micro-LED chip fixedly connected to the substrate using a hybrid bonding process.

6. The Micro-LED display based on hybrid bonding process according to claim 5, characterized in that: The substrate comprises a Si layer, a Ti / Ni / Au layer, a polymer material layer and an indium layer from bottom to top.

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