Three-dimensional packaging glass bonding method and glass bonding structure

Abstract

The embodiment of the invention provides a three-dimensional packaging glass bonding method and a glass bonding structure, which are used for solving the technical problems of long time consumption in the bonding process and low production efficiency of the existing glass bonding method. The three-dimensional packaging glass bonding method comprises the steps of pretreatment of a glass substrate, preparation of a composite film layer serving as a positive high-valence active ion source, formation of a to-be-bonded multi-layer glass structure and laser-induced chemical bonding. According to the method, under the room temperature condition without preheating, the multi-layer glass bonding structure is rapidly and efficiently formed in the mode of inducing ion migration and diffusion through ultraviolet ultrafast laser irradiation and carrying out chemical bonding, annealing treatment is not needed, the technological process is remarkably shortened, and the technological controllability and the production efficiency are improved. The bonding interface of the finally obtained glass bonding structure has the characteristics of uniformity, continuity, compactness, low defect density and high bonding strength, and can meet the requirements on high performance and high reliability in a glass-based three-dimensional packaging scene.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuit packaging, and in particular to a three-dimensional packaging glass bonding method and a glass bonding structure. Background Art

[0002] 3D Packaging uses technologies such as through-holes and adapter plates to vertically stack multiple chips and circuit layers with different functions to build a high-density integrated three-dimensional structure. Compared with traditional two-dimensional packaging methods, 3D packaging has significant advantages in integration, performance, reliability and power consumption.

[0003] The adapter boards used for three-dimensional packaging include silicon-based adapter boards, ceramic-based adapter boards, and glass-based adapter boards. At present, silicon-based adapter boards are widely used due to their high integration, but their high-frequency performance has certain limitations. In contrast, ceramic-based adapter boards excel in high-frequency performance, but their integration has declined. Glass-based adapter boards have both the high-frequency performance advantages of ceramic-based adapter boards and the high integration of silicon-based adapter boards, while being more competitive in terms of process implementation costs. Therefore, glass-based adapter boards are regarded as an important direction for the future development of adapter board technology.

[0004] The three-dimensional packaging process based on the glass-based transfer plate includes the following steps: First, the surfaces of the upper glass transfer plate, the device to be packaged, and the lower glass transfer plate are pretreated to ensure that they are clean and flat. Next, these components are stacked up and down, and their positions are precisely adjusted to achieve alignment. Subsequently, the fluidity and adhesion of the glass material under specific temperature and pressure conditions are utilized, and thermal bonding techniques such as anodic bonding, thermal compression bonding, or eutectic bonding are used to activate the bonding interface so that the materials of the upper glass transfer plate and the lower glass transfer plate are tightly bonded to form a stable multi-layer packaging structure. Finally, the multi-layer packaging structure is annealed to eliminate the thermal stress formed inside.

[0005] However, in the process of implementing the technical solution in the embodiment of the present invention, the inventors found that the existing three-dimensional packaging glass bonding method has at least the following technical problems:

[0006] The bonding process is time-consuming and has low production efficiency. Summary of the invention

[0007] In view of this, an object of the embodiments of the present invention is to provide a three-dimensional packaging glass bonding method and a glass bonding structure to solve the technical problems of the existing glass bonding method, such as the bonding process is time-consuming and the production efficiency is low.

[0008] In order to achieve the above purpose, the technical solutions adopted in the embodiments of the present invention are as follows:

[0009] In a first aspect, an embodiment of the present invention provides a three-dimensional packaging glass bonding method, comprising the following steps:

[0010] Two glass substrates of the same size are prepared, namely a first glass substrate and a second glass substrate; the first glass substrate is subjected to ultrasonic cleaning; the second glass substrate is first subjected to polishing and then subjected to ultrasonic cleaning;

[0011] sequentially coating a seed film layer, a conductive film layer and a titanium film layer on the coating surface of the first glass substrate by magnetron sputtering technology to obtain the first glass substrate having a composite film layer;

[0012] Placing the first glass substrate coated with the titanium thin film layer in an atmospheric environment at room temperature and performing a surface oxidation treatment for a predetermined time to obtain a composite film layer whose outermost film layer is a titanium dioxide film layer;

[0013] The first glass substrate and the second glass substrate are aligned and stacked in a bonding fixture in such a way that the titanium dioxide thin film layer of the first glass substrate directly contacts the polished surface of the second glass substrate, and a predetermined pressure is applied to the first glass substrate and the second glass substrate by adjusting a locking device of the bonding fixture to form a multi-layer glass structure to be bonded;

[0014] The multi-layer glass structure to be bonded is placed on an ultraviolet ultrafast laser bonding device, and the second glass substrate is scanned and irradiated from top to bottom in a manner that the laser focus is focused on the titanium dioxide thin film layer of the first glass substrate, so that the titanium dioxide thin film layer generates positive tetravalent titanium ions and migrates and diffuses toward the second glass substrate, and the second glass substrate generates negative divalent silicon ions and migrates and diffuses toward the titanium dioxide thin film layer, and the positive tetravalent titanium ions are combined with the negative divalent silicon ions to form a titanium disilicide bonding interface between the first glass substrate and the second glass substrate, thereby obtaining a glass bonding structure.

[0015] Optionally, in the step of obtaining the first glass substrate having the composite film layer, the seed film layer has a thickness of 20 to 80 nanometers.

[0016] Optionally, in the step of obtaining the first glass substrate having the composite film layer, the thickness of the conductive film layer is 2 to 4 micrometers.

[0017] Optionally, in the step of obtaining the first glass substrate having the composite film layer, the thickness of the titanium thin film layer is 100 to 300 nanometers.

[0018] Optionally, in the step of obtaining a composite film layer whose outermost film layer is a titanium dioxide film layer, the predetermined time for performing the surface oxidation treatment is 15 to 30 minutes.

[0019] Optionally, in the step of obtaining a composite film layer whose outermost film layer is a titanium dioxide film layer, the structure of the composite film layer obtained is seed film layer / conductive film layer / titanium dioxide film layer.

[0020] Optionally, the step of forming the multi-layer glass structure to be bonded further includes:

[0021] A thin film pressure sensor is installed at the bottom of the bonding fixture, and the contact pressure between the first glass substrate and the second glass substrate is monitored in real time by the thin film pressure sensor.

[0022] In a second aspect, an embodiment of the present invention further provides a glass bonding structure, which is manufactured by the aforementioned three-dimensional packaging glass bonding method.

[0023] Compared with the existing melt bonding method that relies on high temperature and high pressure to enhance the intermolecular forces, the three-dimensional encapsulation glass bonding method in the embodiment of the present invention forms a multi-layer glass bonding structure quickly and efficiently under room temperature conditions without preheating, by inducing ion migration and diffusion through ultraviolet ultrafast laser irradiation and chemical bonding, and does not require annealing treatment, which significantly shortens the process flow and improves process controllability and production efficiency. The bonding interface of the glass bonding structure finally obtained has the characteristics of uniformity, continuity, density, low defect density and high bonding strength, which can meet the requirements of high performance and high reliability in glass-based three-dimensional packaging scenarios. This method effectively solves the technical problems of the existing glass bonding method, such as the long bonding process and low production efficiency, while avoiding the thermal damage that high temperature may cause to the packaged functional devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A schematic flow chart of a three-dimensional encapsulation glass bonding method in an embodiment of the present invention is shown;

[0026] Figure 2 A schematic structural diagram of a three-dimensional encapsulation glass bonding structure in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with practical applications and with reference to the drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. 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 glass bonding structure manufactured by the three-dimensional packaging glass bonding method in the embodiment of the present invention is applied to three-dimensional packaging technology and is particularly suitable for the needs of high-performance and high-reliability packaging.

[0029] The existing glass bonding method has technical problems such as a long bonding process and low production efficiency, which limits the application of glass-based adapter plates in three-dimensional packaging.

[0030] After conducting an in-depth study of the existing glass bonding method, the inventors found that the reason why the existing glass bonding method takes a long time to complete and has low production efficiency is mainly because the existing glass bonding method uses high-temperature hot-pressing melt bonding, which requires a long period of heating to form a high-temperature environment of 300-450°C. Moreover, the glass substrate is prone to deformation under high temperature and high pressure conditions, and the thermal stress formed during the thermal bonding process must also be eliminated through annealing, which further prolongs the process flow.

[0031] In the research of bonding technology, it is found that the bonding between glass substrates can be achieved by melting the glass material in the bonding interface area by laser melting. Laser melting bonding takes a short time and the process is controllable, but it still inevitably forms thermal stress in the final glass bonding structure, which needs to be eliminated by subsequent annealing treatment. The whole process is still too long.

[0032] The inventors further discovered that laser scanning and irradiation of glass substrates can induce the generation of negative divalent silicon ions, forming a low voltage on the glass substrate; laser scanning and irradiation of specific material substrates can induce the generation of positive high-valent ions, forming a high voltage on the specific material substrate; the two substrates are combined, and under the action of the electric field, the positive high-valent ions migrate and diffuse into the glass substrate, and the negative divalent silicon ions migrate and diffuse into the specific material substrate. If the high-valent ions combine with the divalent silicon ions to form a covalent bond, a continuous, uniform, high-quality bonding interface can be constructed between the specific material substrate and the glass substrate, thereby achieving low-temperature rapid chemical bonding between the two. This bonding method is fast and does not require annealing, greatly improving production efficiency.

[0033] In the process of implementing the technical solution in the embodiment of the present invention, the inventors found that a conductive film layer is deposited on a glass substrate used in three-dimensional packaging to provide a conductive function. If a film layer of a specific material is deposited on the conductive film layer as an active ion source, the film layer of the specific material can be irradiated by laser focusing scanning to induce the generation of positive high-valent ions and form a high voltage in the film layer of the specific material; the high voltage and the low voltage of the glass substrate formed by the negative divalent silicon ions generated by the laser scanning irradiation of another glass substrate constitute an electric field. The electric field causes the positive high-valent ions and the negative divalent silicon ions to migrate and diffuse toward each other, and combine at the bonding interface to form a covalent bond structure, so that a continuous and dense bonding interface can be quickly formed between the two glass substrates, thereby achieving efficient glass bonding.

[0034] Based on the above understanding, the inventor provides a three-dimensional packaging glass bonding method, which achieves low-temperature rapid chemical bonding at room temperature by scanning the bonding interface area of ​​two glass substrates with ultraviolet ultrafast laser, significantly shortening the bonding time, improving production efficiency, and effectively avoiding high temperature damage to the packaging functional devices, meeting the needs of high-performance and high-reliability packaging.

[0035] The technical solution of the present invention will be described below in conjunction with the accompanying drawings and embodiments.

[0036] Figure 1 A schematic flow chart of a three-dimensional encapsulation glass bonding method in an embodiment of the present invention is shown;

[0037] Now refer to Figure 1 As shown, an embodiment of the present invention provides a three-dimensional packaging glass bonding method, comprising the following steps:

[0038] S110: preparing two glass substrates of the same size, namely a first glass substrate and a second glass substrate; performing ultrasonic cleaning on the first glass substrate; performing polishing on the second glass substrate and then performing ultrasonic cleaning;

[0039] In the embodiment of the present invention, the first glass substrate and the second glass substrate are made of glass materials used in the field of three-dimensional packaging technology.

[0040] The specific implementation process of step S110 may be:

[0041] Two glass substrates of the same size are prepared, which are referred to as a first glass substrate and a second glass substrate respectively.

[0042] The first glass substrate is placed in a cleaning tank of an ultrasonic cleaning device, a cleaning medium such as a cleaning liquid, ethanol and deionized water is added, and a cleaning time and frequency are set; then, the ultrasonic cleaning device is started, and the first glass substrate is ultrasonically cleaned for a predetermined time using micro-flows and impact forces generated by a cavitation effect of high-frequency vibration to remove impurities and dust on its surface.

[0043] First, a suitable polishing liquid and polishing pad are selected, and the second glass substrate is polished using a polishing device at a predetermined polishing pressure and time to improve its flatness and finish. Then, the polished second glass substrate is placed in a cleaning tank of an ultrasonic cleaning device, and the second glass substrate is ultrasonically cleaned for a predetermined time using the same process and method to remove impurities, processing residues, and residual polishing liquid on its surface.

[0044] Exemplarily, the ultrasonic cleaning time of the first glass substrate and the second glass substrate is 15 to 20 minutes.

[0045] It should be understood that, in the specific implementation process, the first glass substrate and the second glass substrate are further dried after ultrasonic cleaning to ensure that no moisture remains on their surfaces.

[0046] In step S110, the first glass substrate is ultrasonically cleaned to improve its surface cleanliness, thereby enhancing the interface bonding force of its magnetron sputtering coating; the second glass substrate is ultrasonically cleaned to improve its surface cleanliness and enhance its interface bonding performance during the bonding process.

[0047] S120, sequentially coating a seed film layer, a conductive film layer, and a titanium film layer on a coating surface of the first glass substrate by magnetron sputtering technology to obtain the first glass substrate having a composite film layer;

[0048] In the embodiment of the present invention, the thin film deposition technology used is magnetron sputtering technology. Magnetron sputtering technology is to bombard the sputtering target with high-energy ions so that the atoms of the sputtering target are sputtered onto the surface of the first glass substrate to form a thin film layer. Compared with other thin film deposition technologies, the thin film layer formed by magnetron sputtering technology is uniform, has good adhesion, and has strong thickness controllability.

[0049] During the magnetron sputtering process, the working parameters of the magnetron sputtering equipment, such as sputtering power, sputtering time and sputtering gas pressure, need to be precisely controlled to ensure the formation of a uniform thin film layer of predetermined thickness. The selection of working parameters needs to take into account the characteristics of the sputtering target and the sputtering efficiency, while the sputtering time needs to be determined based on the sputtering rate and the required film thickness. The sputtering gas pressure will also affect the sputtering process and the film quality.

[0050] The specific implementation process of step S120 may be:

[0051] A suitable metal or alloy material is selected as the seed film layer material, the first glass substrate is placed in a vacuum chamber of a magnetron sputtering device, and a seed film layer of a certain thickness is deposited on the coating surface of the first glass substrate at a predetermined sputtering power and time.

[0052] A material with good electrical conductivity is selected as the conductive film layer material, and a conductive film layer of a certain thickness is deposited on the seed film layer at a predetermined sputtering power and time.

[0053] High-purity titanium is selected as the material of the titanium thin film layer, and a titanium thin film layer of a certain thickness is deposited on the conductive thin film layer with a predetermined sputtering power and time, so as to finally obtain the first glass substrate with a composite film layer.

[0054] In the embodiment of the present invention, the seed film layer is used to connect the first glass substrate and the subsequently deposited conductive film layer to ensure that the conductive film layer has good adhesion and uniformity.

[0055] In order to improve the adhesion between the subsequently deposited conductive film layer and the first glass substrate, the material of the seed film layer is preferably one of titanium, chromium and tungsten metals. Multiple experiments have shown that the thickness of the seed film layer is 20 to 80 nanometers, which allows the seed film layer to better connect the first glass substrate and the conductive film layer.

[0056] In the embodiment of the present invention, the conductive film layer is used to provide the conductive function for the glass bonding structure finally formed, so as to facilitate the subsequent circuit connection and signal transmission. The material selection and thickness control of the conductive film layer are very important for its conductive performance.

[0057] In order to ensure that the formed conductive film layer has good conductivity, the conductive film layer is preferably one of a copper film layer and a gold film layer. In order to ensure that the conductive film layer has sufficient conductivity, the thickness of the conductive film layer is 2 to 4 microns.

[0058] In the embodiment of the present invention, the titanium film layer is both a base film layer for forming a bonding interface and a precursor film layer for forming a titanium dioxide film layer. The titanium film layer has excellent mechanical properties and structural stability. Using it as a base film layer for forming a bonding interface is beneficial to improving the bonding strength of the bonding interface. The thickness of the titanium film layer is directly related to the thickness of the titanium dioxide film layer formed by subsequent surface oxidation treatment at room temperature.

[0059] Multiple experiments have shown that the titanium dioxide film layer formed when the thickness of the titanium film layer is 100 nanometers or more can serve as an active ion source for ion migration and diffusion, and increasing the thickness of the titanium film layer to more than 300 nanometers has no substantial effect on the quality improvement of the titanium disilicide bonding interface formed.

[0060] A composite film layer consisting of a seed film layer, a conductive film layer and a titanium film layer is formed on the coating surface of the first glass substrate through step S120, wherein the titanium film layer with good mechanical properties and structural stability is used as a base film layer for forming a bonding interface.

[0061] S130, placing the first glass substrate coated with the titanium thin film layer in an atmospheric environment at room temperature, and performing a surface oxidation treatment for a predetermined time to obtain a composite film layer whose outermost film layer is a titanium dioxide film layer;

[0062] The specific implementation process of step S130 may be:

[0063] The first glass substrate coated with the titanium thin film layer is placed in an atmospheric environment at room temperature, the titanium thin film layer is fully in contact with the atmosphere, and the surface of the titanium thin film layer reacts with oxygen in the air to form a titanium dioxide film layer.

[0064] The start time is recorded. After a predetermined period of surface oxidation, the titanium thin film layer of the composite film layer is partially or entirely converted into a titanium dioxide film layer, thereby obtaining a composite film layer whose outermost film layer is a titanium dioxide film layer.

[0065] In the embodiment of the present invention, by controlling the surface oxidation treatment time, the thickness and performance of the titanium dioxide film layer can be controlled to meet different bonding requirements. The surface oxidation treatment time is preferably 15 to 30 minutes.

[0066] If the surface oxidation treatment lasts for less than 15 minutes, the thickness of the titanium dioxide film layer formed is insufficient, which will affect the bonding quality. Generally, the surface oxidation treatment lasting 30 minutes can ensure that the titanium thin film layer is completely converted into a titanium dioxide film layer.

[0067] If the titanium film layer is partially converted into a titanium dioxide film layer, the structure of the composite film layer is seed film layer / conductive film layer / titanium film layer / titanium dioxide film layer. The titanium dioxide film layer serves as a bonding interface for ion migration bonding during the bonding process.

[0068] If the titanium thin film layer is completely converted into a titanium dioxide film layer, the structure of the composite film layer is a seed film layer / conductive film layer / titanium dioxide film layer. Since the titanium thin film layer is completely converted into a titanium dioxide film layer, more active tetravalent titanium ions can be generated. In the subsequent bonding process, the titanium disilicide bonding interface formed by ion migration chemical bonding is thicker, and the first glass substrate and the second glass substrate can be more firmly bonded together.

[0069] The outermost film layer of the composite film layer is converted into a titanium dioxide film layer through step S130. The titanium dioxide film layer has good adhesion and mechanical properties, and can generate active tetravalent titanium ions and migrate and diffuse under laser irradiation.

[0070] S140, placing the first glass substrate and the second glass substrate in a bonding fixture in an aligned manner such that the titanium dioxide thin film layer of the first glass substrate directly contacts the polished surface of the second glass substrate, and applying a predetermined pressure to the first glass substrate and the second glass substrate by adjusting a locking device of the bonding fixture to form a multi-layer glass structure to be bonded;

[0071] The specific implementation process of step S140 may be:

[0072] The first glass substrate with the titanium dioxide thin film layer and the polished second glass substrate are stacked and placed in a bonding fixture in such a way that the titanium dioxide thin film layer of the first glass substrate directly contacts the polished surface of the second glass substrate; and are aligned by a high-precision alignment system until the alignment marks of the first glass substrate and the second glass substrate are completely overlapped.

[0073] By adjusting the locking device of the bonding fixture, such as the locking bolt, pressure is gradually applied to the first glass substrate and the second glass substrate until the required contact pressure is reached, so that the two glass substrates are closely attached to form a multi-layer glass structure to be bonded.

[0074] In the embodiment of the present invention, by applying a predetermined pressure to make the two glass substrates closely fit together, bubbles or voids at the contact interface are effectively reduced, and the effective contact area between the titanium dioxide film layer and the polished surface of the second glass substrate is increased, so as to improve the ion migration and diffusion efficiency at the bonding interface during the bonding process. At the same time, in the subsequent bonding process, the pressure of the first glass substrate and the second glass substrate set in the bonding fixture is kept uniform and appropriate, which is conducive to forming a uniform, continuous, high-quality bonding interface and improving the firmness of the bonding between the first glass substrate and the second glass substrate.

[0075] Overpressure may have an adverse effect on the structures of the two glass substrates, while underpressure is not conducive to effective contact between the titanium dioxide film layer and the polished surface of the second glass substrate.

[0076] In order to ensure that the pressure applied to the first glass substrate and the second glass substrate is controlled within a predetermined range, step S140 also includes: installing a thin film pressure sensor at the bottom of the bonding fixture to monitor the contact pressure between the first glass substrate and the second glass substrate in real time through the thin film pressure sensor.

[0077] In the embodiment of the present invention, the thin film pressure sensor used has high sensitivity and high stability, and ensures that its measurement range can cover the expected contact pressure. The contact pressure data between the first glass substrate and the second glass substrate are collected in real time by the thin film pressure sensor, and the pressure of the bonding fixture is adjusted in time according to the pressure data to ensure that the contact pressure between the first glass substrate and the second glass substrate is maintained within a predetermined range.

[0078] In step S140 , the first glass substrate and the second glass substrate are closely attached to each other to form a multi-layer glass structure to be bonded in a manner that facilitates ion migration and diffusion.

[0079] S150, placing the multi-layer glass structure to be bonded on an ultraviolet ultrafast laser bonding device, and scanning and irradiating the second glass substrate from top to bottom in a manner that the laser focus is focused on the titanium dioxide thin film layer of the first glass substrate, so that the titanium dioxide thin film layer generates positive tetravalent titanium ions and migrates and diffuses toward the second glass substrate, and the second glass substrate generates negative divalent silicon ions and migrates and diffuses toward the titanium dioxide thin film layer, and the positive tetravalent titanium ions are combined with the negative divalent silicon ions to form a titanium disilicide bonding interface between the first glass substrate and the second glass substrate, thereby obtaining a glass bonding structure.

[0080] The laser used in the embodiment of the present invention is an ultraviolet ultrafast laser. Compared with other lasers, the ultraviolet ultrafast laser has the characteristics of high energy density and high processing precision, and is very suitable for the rapid migration and diffusion of ions.

[0081] The specific implementation process of step S150 may be:

[0082] The bonding fixture containing the multi-layer glass structure to be bonded is placed on the workbench of the ultraviolet ultrafast laser bonding equipment in a manner that the second glass substrate is on top, ensuring that the multi-layer glass structure is located on the laser scanning path.

[0083] Adjust the working parameters of the ultraviolet ultrafast laser bonding equipment, including laser irradiation power, laser pulse number, processing type, scanning speed, acceleration and scanning path. The laser focus needs to be focused on the titanium dioxide thin film layer of the first glass substrate.

[0084] Start the ultraviolet ultrafast laser bonding equipment, scan and irradiate the second glass substrate from top to bottom, and the laser penetrates the second glass substrate and irradiates the titanium dioxide thin film layer of the first glass substrate. Under laser irradiation, the titanium dioxide thin film layer at the laser focus rapidly heats up, generating positive tetravalent titanium ions, forming a high voltage in the titanium dioxide thin film layer, and the second glass substrate near the laser focus rapidly heats up, generating negative divalent silicon ions, forming a low voltage in the second glass substrate; under the action of the electric field, the positive tetravalent titanium ions migrate and diffuse toward the second glass substrate, and the negative divalent silicon ions migrate and diffuse toward the titanium dioxide thin film layer, and the two combine to form a covalent bond structure of titanium disilicide (TiSi2), thereby forming a continuous and dense titanium disilicide bonding interface between the first glass substrate and the second glass substrate. The first glass substrate and the second glass substrate are firmly bonded as a whole through the titanium disilicide bonding interface to obtain a glass bonding structure.

[0085] It can be seen that the three-dimensional encapsulation glass bonding method in the embodiment of the present invention forms the titanium dioxide film layer on the bonding surface of the first glass substrate as an active ion source for ion migration and diffusion. Under room temperature conditions without preheating, ultraviolet ultrafast laser with high energy density and short pulse characteristics is used to penetrate the second glass substrate, and the titanium dioxide film layer of the first glass substrate is focused and scanned to form a local high temperature in the bonding interface area, inducing the titanium dioxide film layer to generate positive tetravalent titanium ions, forming a high voltage in the titanium dioxide film layer, inducing the second glass substrate to generate negative divalent silicon ions, forming a low voltage in the second glass substrate, and under the action of the electric field, the positive tetravalent titanium ions migrate and diffuse to the second glass substrate, and the negative divalent silicon ions migrate and diffuse to the titanium dioxide film layer, and the two are chemically bonded to form a covalent bond structure of titanium disilicide, so as to achieve low-temperature rapid bonding, and form a continuous, uniform, dense, and high-quality bonding interface between the first glass substrate and the second glass substrate.

[0086] First, the first glass substrate is ultrasonically cleaned to enhance the interface bonding strength of its coating surface, and the polished second glass substrate is ultrasonically cleaned to enhance its interface bonding performance during the bonding process.

[0087] Secondly, a seed film layer, a conductive film layer and a titanium film layer are sequentially coated on the coating surface of the first glass substrate by magnetron sputtering technology, and the titanium film layer is partially or wholly converted into the titanium dioxide film layer by surface oxidation treatment, which serves as an active ion source for laser irradiation-induced ion migration and diffusion.

[0088] Subsequently, the titanium dioxide thin film layer of the first glass substrate is directly contacted with the polished surface of the second glass substrate, and is aligned and stacked by a bonding fixture, and a predetermined pressure is applied to make the titanium dioxide thin film layer fit tightly with the polished surface of the second glass substrate, thereby increasing the effective contact area and improving the ion migration and diffusion efficiency in the subsequent laser bonding process.

[0089] Finally, a high-energy-density, short-pulse ultraviolet ultrafast laser is used to scan and irradiate the titanium dioxide thin film through the second glass substrate, forming local high-temperature areas on both sides of the contact surface, inducing the titanium dioxide thin film layer to generate positive tetravalent titanium ions to form a high voltage, and inducing the second glass substrate to generate negative divalent silicon ions to form a low voltage; under the action of the electric field, the positive tetravalent titanium ions migrate and diffuse toward the second glass substrate, and the negative divalent silicon ions migrate and diffuse toward the titanium dioxide thin film layer, and the two combine to form a covalent bond structure of titanium disilicide, thereby forming a continuous, uniform, dense, high-quality titanium disilicide bonding interface at room temperature, and firmly bonding the two glass substrates into a whole.

[0090] Compared with the existing melt bonding method that relies on high temperature and high pressure to enhance the intermolecular forces, the three-dimensional encapsulation glass bonding method in the embodiment of the present invention forms a multi-layer glass bonding structure quickly and efficiently under room temperature conditions without preheating, by inducing ion migration and diffusion through ultraviolet ultrafast laser irradiation and chemical bonding, and does not require annealing treatment, which significantly shortens the process flow and improves process controllability and production efficiency. The bonding interface of the glass bonding structure finally obtained has the characteristics of uniformity, continuity, density, low defect density and high bonding strength, which can meet the requirements of high performance and high reliability in glass-based three-dimensional packaging scenarios. This method effectively solves the technical problems of the existing glass bonding method, such as the long bonding process and low production efficiency, while avoiding the thermal damage that high temperature may cause to the packaged functional devices.

[0091] Figure 2 A schematic structural diagram of a three-dimensional encapsulation glass bonding structure in an embodiment of the present invention is shown.

[0092] Now refer to Figure 2 As shown, a glass bonding structure is also provided in an embodiment of the present invention, and the glass bonding structure is manufactured by the above-mentioned three-dimensional packaging glass bonding method.

[0093] The glass bonding structure comprises

[0094] A first glass substrate; a composite film layer including a seed film layer and a conductive film layer is deposited on the bonding surface of the first glass substrate; the conductive film layer is used to provide a conductive path;

[0095] A second glass substrate; the bonding surface of the second glass substrate is polished before bonding;

[0096] The titanium disilicide bonding interface is used to bond the first glass substrate and the second glass substrate; the titanium disilicide bonding interface is a chemical bonding bonding interface formed by focusing, scanning and irradiating the titanium dioxide thin film layer of the composite film layer using ultraviolet ultrafast laser technology.

[0097] The glass bonding structure in the embodiment of the present invention is applied to three-dimensional packaging technology to perform three-dimensional packaging of functional chips and circuits.

[0098] It should be understood that the glass bonding structure in the embodiment of the glass bonding structure of the present invention is a glass bonding structure manufactured by the bonding method in the embodiment of the three-dimensional packaging glass bonding method of the present invention. For the convenience and simplicity of description, the manufacturing method and material selection in the embodiment of the glass bonding structure of the present invention can refer to the relevant description in the embodiment of the three-dimensional packaging glass bonding method, and will not be repeated here.

Claims

1. A three-dimensional encapsulation glass bonding method, characterized in that: The following steps are involved: preparing two glass substrates of the same size, namely a first glass substrate and a second glass substrate; performing ultrasonic cleaning on the first glass substrate; The second glass substrate is firstly polished and then ultrasonically cleaned; sequentially coating a seed film layer, a conductive film layer and a titanium film layer on the coating surface of the first glass substrate by magnetron sputtering technology to obtain the first glass substrate having a composite film layer; Placing the first glass substrate coated with the titanium thin film layer in an atmospheric environment at room temperature and performing a surface oxidation treatment for a predetermined time to obtain a composite film layer whose outermost film layer is a titanium dioxide film layer; The first glass substrate and the second glass substrate are aligned and stacked in a bonding fixture in such a way that the titanium dioxide thin film layer of the first glass substrate directly contacts the polished surface of the second glass substrate, and a predetermined pressure is applied to the first glass substrate and the second glass substrate by adjusting a locking device of the bonding fixture to form a multi-layer glass structure to be bonded; The multi-layer glass structure to be bonded is placed on an ultraviolet ultrafast laser bonding device, and the second glass substrate is scanned and irradiated from top to bottom in a manner that the laser focus is focused on the titanium dioxide thin film layer of the first glass substrate, so that the titanium dioxide thin film layer generates positive tetravalent titanium ions and migrates and diffuses toward the second glass substrate, and the second glass substrate generates negative divalent silicon ions and migrates and diffuses toward the titanium dioxide thin film layer, and the positive tetravalent titanium ions are combined with the negative divalent silicon ions to form a titanium disilicide bonding interface between the first glass substrate and the second glass substrate, thereby obtaining a glass bonding structure.

2. The three-dimensional encapsulation glass bonding method according to claim 1, characterized in that: In the step of obtaining the first glass substrate having the composite film layer, the thickness of the seed film layer is 20 to 80 nanometers.

3. The three-dimensional encapsulation glass bonding method according to claim 1, characterized in that: In the step of obtaining the first glass substrate having the composite film layer, the thickness of the conductive film layer is 2 to 4 micrometers.

4. The three-dimensional packaging glass bonding method according to claim 1, characterized in that: In the step of obtaining the first glass substrate having the composite film layer, the thickness of the titanium thin film layer is 100 to 300 nanometers.

5. The three-dimensional encapsulation glass bonding method according to any one of claims 1 to 4, characterized in that: In the step of obtaining a composite film layer whose outermost film layer is a titanium dioxide film layer, the predetermined time for performing the surface oxidation treatment is 15 to 30 minutes.

6. The three-dimensional encapsulation glass bonding method according to any one of claims 1 to 4, characterized in that: In the step of obtaining a composite film layer whose outermost film layer is a titanium dioxide film layer, the structure of the composite film layer obtained is a seed film layer / conductive film layer / titanium dioxide film layer.

7. The three-dimensional encapsulation glass bonding method according to any one of claims 1 to 4, characterized in that: The step of forming the multi-layer glass structure to be bonded also includes: A thin film pressure sensor is installed at the bottom of the bonding fixture, and the contact pressure between the first glass substrate and the second glass substrate is monitored in real time by the thin film pressure sensor.

8. A glass bonding structure, characterized in that: The glass bonding structure is manufactured by the three-dimensional packaging glass bonding method according to any one of claims 1 to 7.

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