Chip on film, display device and manufacturing method

Abstract

The application provides a chip on film, a display device and a preparation method. The chip on film comprises a substrate, a patterned metal trace arranged on the substrate, an encapsulation layer arranged on a side of the metal trace away from the substrate, a metal pin arranged on a side of the encapsulation layer away from the substrate and fixedly connected to a side of the metal trace away from the substrate, and a barrier layer arranged on a side of the encapsulation layer away from the substrate and connected to the metal pin and configured to seal a gap between the metal pin and the encapsulation layer. The barrier layer can seal the gap between the encapsulation layer and the metal pin, avoid corrosion of the metal pin by acid liquid during a tin plating process, prevent the metal pin from peeling or separating from the surface, and improve the bending performance of the chip on film.

Description

Technical Field

[0001] This application relates to the field of flip-chip film technology, and in particular to a flip-chip film, a display device, and a method for preparing it. Background Technology

[0002] With the continuous development of technology, people have higher and higher requirements for display devices. Among them, display devices with good display effects and viewing experience often contain a large number of complex data channels to ensure stable transmission of data in the display device.

[0003] In related technologies, ChipOnFlex (or ChipOnFilm, COF) technology is a technique that uses thermoforming to bond metal pads on an Integrated Circuit Chip (IC) to metal leads of a flexible circuit. Typically, the metal leads on the COF are made of copper and are used to connect the metal traces in the COF to the metal pads of the IC chip, enabling data transmission between the IC chip and the COF. To prevent oxidation of the metal leads and ensure the reliability of the connection between the metal leads and the IC chip's metal pads, the metal leads need to undergo a tinning process. However, due to poor adhesion between the metal leads and the encapsulation layer in the COF, tiny gaps can form between them. The acid generated during the tinning process can easily enter these gaps, causing peeling at the bottom of the metal leads, affecting the bending performance of the COF, and reducing the yield rate of the COF. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a flip-chip thin film, a display device, and a method for its preparation.

[0005] To achieve the above objectives, this application provides a flip-chip thin film, comprising:

[0006] A substrate on which patterned metal traces are arranged;

[0007] An encapsulation layer is disposed on the side of the metal trace away from the substrate, and the orthographic projection of the metal trace on the substrate covers the orthographic projection of the metal trace on the substrate.

[0008] Metal pins are disposed on the side of the encapsulation layer away from the substrate and are fixedly connected to the side of the metal trace away from the substrate.

[0009] A barrier layer, disposed on the side of the encapsulation layer away from the substrate and connected to the metal pins, is configured to seal the gap between the metal pins and the encapsulation layer.

[0010] Optionally, the thickness of the barrier layer is 500-1000 Å.

[0011] Optionally, the barrier layer is made of at least one of silicon nitride and silicon oxide.

[0012] Optionally, multiple metal pins are arranged in an array on the packaging layer.

[0013] Optionally, the metal pin includes:

[0014] The first connecting portion is fixedly connected to the side of the metal trace away from the substrate, and the orthographic projection of the barrier layer on the substrate surrounds the orthographic projection of the first connecting portion on the substrate.

[0015] Optionally, the flip-chip film further includes:

[0016] The first adapter hole is disposed on the encapsulation layer, and its orthogonal projection on the substrate is located within the orthogonal projection of the metal trace on the substrate. The first connection portion is located within the first adapter hole.

[0017] The second adapter hole is disposed on the barrier layer, and its orthogonal projection on the substrate covers the orthogonal projection of the first adapter hole on the substrate. The first connecting portion is located inside the second adapter hole.

[0018] Optionally, the metal pin further includes:

[0019] The second connecting part is fixedly connected to the side of the first connecting part away from the substrate, and is also connected to the side of the barrier layer away from the substrate.

[0020] Optionally, the metal pin further includes:

[0021] The first contact surface is disposed on the side of the second connection portion near the substrate and connected to the side of the barrier layer away from the substrate.

[0022] Optionally, the metal pin further includes:

[0023] The second contact surface is disposed on the side of the second connection portion away from the substrate, and its orthographic projection on the substrate is located within the orthographic projection of the first contact surface on the substrate.

[0024] Optionally, the flip-chip film further includes:

[0025] The soldering green oil is disposed on the side of the encapsulation layer away from the substrate, and its orthogonal projection on the substrate is outside the range of the orthogonal projection of the second connection portion on the substrate.

[0026] Based on the same inventive concept, this application also provides a display device, including the flip-chip thin film described in any of the above embodiments.

[0027] Based on the same inventive concept, this application also provides a method for preparing a flip-chip thin film, comprising:

[0028] A substrate is provided, on which metal traces and a packaging layer are sequentially formed, and a first adapter hole is fabricated on the packaging layer by photolithography.

[0029] A barrier layer is formed on the side of the encapsulation layer away from the substrate by a deposition process, and a second adapter hole communicating with the first adapter hole is made on the barrier layer by a photolithography and etching process.

[0030] The first connection portion of the metal pin is fabricated sequentially in the first and second adapter holes by a seed layer deposition process, and the second connection portion of the metal pin is fabricated by photolithography and electroplating processes, and the second connection portion of the metal pin is connected to the barrier layer.

[0031] Optionally, the preparation method further includes:

[0032] The barrier layer outside the range of the orthogonal projection of the second connection portion on the substrate is removed by photolithography and etching processes.

[0033] Optionally, the thickness of the barrier layer is 500-1000 Å.

[0034] Optionally, the barrier layer is made of at least one of silicon nitride and silicon oxide.

[0035] As can be seen from the above, the flip-chip film, display device and preparation method provided in this application can seal the gap between the encapsulation layer and the metal pin by setting a barrier layer on the side of the encapsulation layer away from the substrate. This can block the acid liquid during the tinning process of the metal pin, prevent the acid liquid from entering the gap and corroding the surface of the metal pin, avoid the problem of surface peeling or falling off of the metal pin, and improve the bending performance of the flip-chip film and the yield of the product. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a diagram showing the usage state of the flip-chip film in the embodiments of this application;

[0038] Figure 2 This is a schematic diagram of the structure of the flip-chip thin film in the embodiments of this application;

[0039] Figure 3 This is a schematic diagram of the structure of the metal pins in the embodiments of this application;

[0040] Figure 4 This is a schematic flowchart of the method for preparing the flip-chip thin film in the embodiments of this application;

[0041] Figure 5 This is a schematic diagram illustrating the process of providing a substrate in an embodiment of this application;

[0042] Figures 6A-6G This is a schematic diagram illustrating the fabrication of the substrate in an embodiment of this application.

[0043] Wherein: 100, substrate; 110, base layer; 120, buffer layer; 200, metal trace; 300, metal pin; 310, first connection part; 320, second connection part; 330, first contact surface; 340, second contact surface; 400, encapsulation layer; 500, barrier layer; 610, first adapter hole; 620, second adapter hole; 710, IC chip; 720, metal pad; 800, soldering solder mask; 900, glass substrate. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0045] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0046] In related technologies, such as Figure 1As shown, in typical cases, the metal leads on the flip-chip film are made of copper and are used to connect the metal traces in the flip-chip film to the metal pads of the IC chip, enabling data transmission between the IC chip and the flip-chip film. The entire flip-chip film can be divided into bonding and unbonding areas; the metal leads are located within the bonding area, while the area surrounding the metal leads is the unbonding area. To prevent oxidation of the metal leads in the flip-chip film and to ensure a secure connection between the metal leads and the IC chip's metal pads for data transmission, a tinning process is required to treat the metal leads. However, due to the poor adhesion between the metal leads and the encapsulation layer in the flip-chip film, tiny gaps can form between them, reducing the strength of the metal lead connection within the flip-chip film. Furthermore, during the tinning process, the acid used can easily enter the gaps and corrode the metal leads, causing surface peeling at the bottom of the metal leads. In severe cases, the acid can even enter the connection between the metal leads and the metal traces, reducing the connection strength and leading to metal lead detachment. This affects the bending performance of the flip-chip film during use and reduces the yield rate of flip-chip film products.

[0047] In view of this, this application provides a flip-chip film, including a substrate 100 on which patterned metal traces 200 are arranged; an encapsulation layer 400 disposed on the side of the metal traces 200 away from the substrate 100, the orthographic projection of the metal traces 200 on the substrate 100 covering the orthographic projection of the metal traces 200 on the substrate 100; metal leads 300 disposed on the side of the encapsulation layer 400 away from the substrate 100 and fixedly connected to the side of the metal traces 200 away from the substrate 100; and a barrier layer 500 disposed on the side of the encapsulation layer 400 away from the substrate 100 and connected to the metal leads 300, configured to seal the gap between the metal leads 300 and the encapsulation layer 400.

[0048] Specifically, such as Figure 2 and Figure 3As shown, this application provides a flip-chip film, wherein the flip-chip film includes a substrate 100 for providing corresponding mounting positions for components in the flip-chip film, thereby supporting and protecting the components; patterned metal traces 200 formed by a patterning process are disposed on the substrate 100, serving as data transmission channels for the flip-chip film, and can be fixedly connected to the metal pads 720 of an IC chip 710 through metal pins 300, thereby realizing data transmission between the IC chip 710 and the flip-chip film; an encapsulation layer 400 is disposed on the side of the metal traces 200 away from the substrate 100, which can cover the metal traces 200 and connect the metal traces 200 and the metal pins 300. The connection points are wrapped to protect the metal traces 200 and their connection points with the metal pins 300, ensuring the stability and reliability of data transmission. By setting a barrier layer 500 on the side of the encapsulation layer 400 away from the substrate 100 and connecting the barrier layer 500 to the metal pins 300, the barrier layer 500 is located between the encapsulation layer 400 and the metal pins 300 and seals the gap between them. This can block the acid in the tin melting process, preventing the acid from flowing into the bottom of the metal pins 300 through the gap between the metal pins 300 and the encapsulation layer 400. This prevents the surface of the metal pins 300 from peeling off or detaching due to corrosion, ensuring the integrity of the metal pins 300 and effectively improving the yield of flip-chip thin film products.

[0049] Furthermore, due to the poor adhesion between the encapsulation layer 400 and the metal pin 300, when the flip-chip film is in a bent state, the metal pin 300 is prone to detach from the encapsulation layer 400 due to the surface stress of the encapsulation layer 400, affecting the firmness of the connection between the metal pin 300 and the encapsulation layer 400. Therefore, the barrier layer 500 can be formed of an adhesive material and placed between the metal pin 300 and the encapsulation layer 400, so that it is connected to the metal pin 300 and the encapsulation layer 400 respectively, thereby improving the firmness of the connection between the metal pin 300 and the encapsulation layer 400, preventing the metal pin 300 from falling off when the flip-chip film is in a bent state, and improving the bending performance of the flip-chip film. In addition, the encapsulation layer 400 mentioned above can be formed of a resin material with good photosensitivity and high ductility, such as a resin layer formed by one or more of polyimide resin, phenoxy resin and epoxy resin, thereby increasing the bending performance of the flip-chip film.

[0050] It should be noted that in the flip-chip film, the substrate 100 is used to support and protect the components in the flip-chip film. The substrate 100 may include at least one base layer 110 and at least one buffer layer 120, specifically as follows: Figure 2As shown; on the one hand, in order to improve the bending ability of the flip-chip film, the substrate 110 can be set as a flexible substrate 110, and can be formed by one or more of materials such as polyimide (PI) and polycarbonate, so that the substrate 110 has better impact resistance and water and oxygen barrier ability, effectively extending the service life of the display device.

[0051] On the other hand, by fabricating a buffer layer 120 on the substrate 100, the surface stress of the base layer 110 can be improved, preventing warping of the base layer 110 during fabrication, thereby ensuring the flatness of the substrate 100 in the flip-chip film; and the flip-chip film can also buffer and protect the internal components during use; wherein, the buffer layer 120 can be formed of inorganic materials such as silicon oxide (SiO) or silicon nitride (SiN), and can be formed on the base layer 110 by a deposition process so that it can cover the surface of the substrate 100; in addition, the specific number of application layers of the base layer 110 and the buffer layer 120 can be determined according to the actual fabrication of the flip-chip film, which will not be elaborated here.

[0052] In some embodiments, the thickness of the barrier layer 500 is 500-1000 Å; wherein, the thickness of the barrier layer 500 can be controlled within the range of 500-1000 Å, such as the barrier layer 500 being 500 Å, 750 Å, or 1000 Å; when the thickness of the barrier layer 500 is set to any thickness within 500-1000 Å, the overall thickness of the flip-chip film will not be too thick, while ensuring a good connection between it and the encapsulation layer 400 and the metal pin 300, so that it can play a good sealing role.

[0053] In some embodiments, the barrier layer 500 is made of at least one of silicon nitride and silicon oxide. By using silicon nitride and / or silicon oxide to make the barrier layer 500, it achieves good adhesion between the barrier layer 500 and the encapsulation layer 400 and the metal pin 300, thereby improving the reliability of the metal pin 300. At the same time, the barrier layer 500 formed of silicon nitride and / or silicon oxide can seal the gap between the encapsulation layer 400 and the bottom of the metal pin 300, preventing the metal pin 300 from being corroded by acid during the tinning process.

[0054] In some embodiments, multiple metal pins 300 are arranged in an array on the package layer 400, such as... Figure 2 As shown, by setting multiple metal pins 300 in the flip-chip film and arranging the multiple metal pins 300 in an array on the side of the encapsulation layer 400 away from the substrate 100, so as to fix them to the metal pads 720 of the IC chip 710, the connection of the IC chip 710 in the flip-chip film is improved. At the same time, the number of data channels used for data transmission can be increased or decreased to ensure stable data transmission.

[0055] In some embodiments, the metal pin 300 includes: a first connection portion 310, which is fixedly connected to the side of the metal trace 200 away from the substrate 100, and the orthographic projection of the barrier layer 500 on the substrate 100 surrounds the orthographic projection of the first connection portion 310 on the substrate 100.

[0056] Specifically, such as Figure 2 and Figure 3 As shown, in the flip-chip film, one side of the metal pin 300 is fixedly connected to the metal trace 200, and the other side is fixedly connected to the metal pad 720 of the IC chip 710, so that the IC chip 710 can transmit data between the flip-chip film and the metal trace 200. The barrier layer 500 is positioned so that its orthographic projection on the substrate 100 surrounds the orthographic projection of the first connection portion 310 on the substrate 100, thereby sealing the area around the first connection portion 310 and the first connection portion 310 of the metal pin 300. This prevents acid from corroding the surface of the first connection portion 310 and its connection with the metal trace 200, ensuring the strong connection of the metal pin 300 to the metal trace 200.

[0057] In some embodiments, the flip-chip film further includes: a first adapter hole 610 disposed on the encapsulation layer 400, the orthographic projection of which on the substrate 100 lies within the orthographic projection of the metal trace 200 on the substrate 100, and a first connection portion 310 located within the first adapter hole 610; and a second adapter hole 620 disposed on the barrier layer 500, the orthographic projection of which on the substrate 100 covers the orthographic projection of the first adapter hole 610 on the substrate 100, and the first connection portion 310 located within the second adapter hole 620.

[0058] Specifically, such as Figure 2 and Figure 3As shown, in the flip-chip film, by providing a first adapter hole 610 on the encapsulation layer 400, and ensuring that the orthographic projection of the first adapter hole 610 on the substrate 100 lies within the orthographic projection of the metal trace 200 on the substrate 100, even if the end of the first adapter hole 610 is located on the surface of the metal trace, the first connection portion 310 of the metal pin 300 disposed within the first adapter hole 610 can be fully connected to the metal trace 200 for data transmission; simultaneously, by providing a second adapter hole on the barrier layer 500... 620, and make the orthographic projection of the second adapter hole 620 on the substrate 100 cover the orthographic projection of the first adapter hole 610 on the substrate 100, so that the barrier layer 500 arranged around the second adapter hole 620 can seal the edge area of ​​the first connection portion 310, which can prevent the acid liquid used in the tin melting process, avoid the acid liquid from corroding the surface of the first connection portion 310 and the connection part between it and the metal trace 200, ensure the firmness of the connection between the metal pin 300 and the metal trace 200, and prevent short circuit.

[0059] In some embodiments, the metal pin 300 further includes a second connection portion 320, which is fixedly connected to the side of the first connection portion 310 away from the substrate 100, and connected to the side of the barrier layer 500 away from the substrate 100.

[0060] Specifically, such as Figure 2 and Figure 3 As shown, in the flip-chip film, one side of the metal pin 300 is fixedly connected to the metal trace 200, and the other side is fixedly connected to the metal pad 720 of the IC chip 710, so that the IC chip 710 can transmit data between the flip-chip film and the metal trace 200. The second connection portion 320 of the metal pin 300 is fixedly connected to one side of the first connection portion 310 for connection with the metal pad 720 of the IC chip 710. The radius of the second connection portion 320 can be set to be larger than the radius of the first connection portion 310, which can increase the connection between the second connection portion 320 and the metal pad 720, improving the strength of the connection with the IC chip 710. Furthermore, the second connection portion 320 is connected to the side of the barrier layer 500 away from the substrate 100, which can prevent acid from entering the gap and corroding the first connection portion 310, and also prevent acid from corroding the bottom of the second connection portion 320, thus preventing surface peeling of the bottom of the second connection portion 320.

[0061] In some embodiments, the metal pin 300 further includes a first contact surface 330 disposed on the side of the second connection portion 320 near the substrate 100 and connected to the side of the barrier layer 500 away from the substrate 100.

[0062] Specifically, such as Figure 2 and Figure 3As shown, by setting the first contact surface 330 on the side of the second connection portion 320 near the substrate 100 and connecting it to the side of the barrier layer 500 away from the substrate 100, the barrier layer 500 can adhere to the first contact surface 330 of the second connection portion 320 and cover at least a portion of the first contact surface 330. This prevents acid from entering the gap between the encapsulation layer 400 and the second connection portion 320 during the tinning process, ensuring that the first contact surface 330 will not peel off due to corrosion and ensuring that the metal pin 300 has good integrity.

[0063] In some embodiments, the metal pin 300 further includes a second contact surface 340 disposed on the side of the second connection portion 320 away from the substrate 100, and the orthographic projection of the second contact surface 330 on the substrate 100 is located within the orthographic projection of the first contact surface 330 on the substrate 100.

[0064] Specifically, such as Figure 2 and Figure 3 As shown, by setting the second contact surface 340 on the side of the second connection portion 320 away from the substrate 100, and making the orthographic projection of the second contact surface 340 on the substrate 100 located within the orthographic projection of the first contact surface 330 on the substrate 100, the second connection portion 320 forms a platform structure above the barrier layer 500. This allows the side and top surfaces of the second connection portion 320 to be covered with tin during the tinning process of the metal pin 300, forming a uniform protective layer on the surface of the second connection portion 320 to prevent oxidation of the metal pin 300. It also ensures a good connection between the metal pin 300 and the metal pad 720 of the IC chip 710.

[0065] In some embodiments, the flip-chip film further includes: soldering solder mask 800, disposed on the side of the encapsulation layer 400 away from the substrate 100, with its orthographic projection on the substrate 100 located outside the range of the orthographic projection of the second connection portion 320 on the substrate 100.

[0066] Specifically, such as Figure 2 and Figure 3As shown, by coating the side of the encapsulation layer 400 away from the substrate 100 with soldering solder 800, and distributing the soldering solder 800 outside the range of the orthogonal projection of the second connection portion 320 on the substrate 100, the soldering solder 800 is uniformly applied to the non-bonding area of ​​the flip-chip film and covers the non-bonding area. The soldering solder 800 can form a protective layer on the encapsulation layer 400, preventing damage to the encapsulation layer 400 when soldering the metal pins 300 and the metal pads 720 of the IC driver chip, ensuring the integrity of the flip-chip film. Furthermore, since the soldering solder 800 has good adhesion and ductility, it will not exert a restraining force on the flip-chip film in a bent state, allowing the flip-chip film to bend normally. In addition, the soldering solder 800 mentioned above can be made of materials such as hydroquinone epoxy resin, phenolic epoxy resin, phenolic epoxy resin, and ethyl aminocarbamate, which will not be described in detail here.

[0067] Based on the same inventive concept, this application also provides a display device including a flip-chip film of any of the above embodiments; wherein, since the display device may include the flip-chip film of any of the above embodiments, the display device has all the beneficial effects of the flip-chip film; in addition, the display device can be a mobile phone, or a tablet computer, television, smartwatch, VR glasses and other display devices, which will not be described in detail here.

[0068] Based on the same inventive concept, this application also provides a method for preparing a flip-chip thin film, specifically as follows: Figure 4 As shown, it includes:

[0069] Step S1: Provide a substrate 100, and sequentially form a metal trace 200 and a packaging layer 400 on the substrate 100. Then, fabricate a first adapter hole 610 on the packaging layer 400 using a photolithography process.

[0070] In this step, such as Figures 6A-6C As shown, metal traces 200 and encapsulation layer 400 can be sequentially fabricated on the provided substrate 100. When fabricating the metal traces 200, a sputtering device can be used to fabricate them, and a metal layer can be formed on the substrate 100 by sputtering deposition. The metal layer is then patterned by dry etching in the photolithography process to form patterned metal traces 200.

[0071] After that, as Figure 6D As shown, a coating process can be used to coat the substrate 100 with an encapsulation layer 400 so that the encapsulation layer 400 covers the metal traces 200, while adjusting the thickness and flatness of the substrate 100.

[0072] Finally, as Figure 6DAs shown, the first adapter hole 610 can be etched on the packaging layer 400 by photolithography, and the orthographic projection of the first adapter hole 610 on the substrate 100 is located within the orthographic projection of the metal trace 200 on the substrate 100, so that the metal pin 300 connected to the metal trace 200 can be fabricated in the first adapter hole 610 later.

[0073] In addition, the material of the metal trace 200 mentioned above can be formed from titanium (Ti) and aluminum (Al) and their alloys, and the specific number of layers can be selected according to the actual situation; the encapsulation layer 400 can be a resin material with good photosensitivity and strong ductility, such as one or more of polyimide resin, phenoxy resin and epoxy resin, which will not be elaborated here.

[0074] Step S2: A barrier layer 500 is formed on the side of the encapsulation layer 400 away from the substrate 100 by a deposition process, and a second transition hole 620 communicating with the first transition hole 610 is made on the barrier layer 500 by a photolithography process and an etching process.

[0075] In this step, such as Figure 6E As shown, after the metal trace 200 is fabricated, a barrier layer 500 can be formed on the side of the packaging layer 400 away from the substrate 100 by using a PECVD (Plasma Enhanced Chemical Vapor Deposition) device through vapor deposition. Using photoresist as a mask, the barrier layer 500 is etched through photolithography and etching processes to etch a second transition hole 620 on the barrier layer 500 that corresponds to and communicates with the first transition hole 610. In the future, a metal pin 300 connected to the metal trace 200 can be fabricated in the second transition hole 620.

[0076] Step S3: The first connecting portion 310 of the metal pin 300 is formed in the first adapter hole 610 and the second adapter hole 620 by means of a seed layer deposition process. The second connecting portion 320 of the metal pin 300 is formed by means of photolithography and electroplating processes, and the second connecting portion 320 of the metal pin 300 is connected to the barrier layer 500.

[0077] In this step, such as Figure 6F As shown, the first connection portion 310 of the metal pin 300 can be fabricated in the first adapter hole 610 and the second adapter hole 620 using the Supper device, and the first connection portion 310 of the metal pin 300 is located inside the first adapter hole 610 and the second adapter hole 620.

[0078] Then, the second connection portion 320 of the metal pin 300 is prepared by photolithography thick barrier process and electroplating thick metal process. To ensure that the metal pin 300 can be stably connected to the metal pad 720 of IC chip 710, the thickness of the second connection portion 320 of the metal pin 300 can be 5-10μm.

[0079] In some embodiments, such as Figure 5 As shown, a substrate 100 is provided, specifically including:

[0080] Step S11: Provide a glass substrate 900 and prepare a substrate 100 on the glass substrate 900 by a coating process;

[0081] In this step, the glass substrate 900 can be used as a carrier for fabricating the substrate 100. The substrate 100 may include a base layer 110 and a buffer layer 120 for supporting and protecting components within the flip-chip film, providing corresponding mounting positions for components disposed on its surface. The substrate 100 may include at least one base layer 110 and at least one buffer layer 120. Each base layer 110 may consist of at least one PI substrate, and the thickness of any base layer 110 may be 15-20 μm. For example, as... Figure 6A As shown, when the substrate 110 includes two PI substrates, a coating process can be used to coat the glass substrate 900 twice in sequence to prepare the stacked substrate 110. The thickness of any PI substrate can be 15 μm to form a substrate 110 with a thickness of 30 μm.

[0082] Step S12: A buffer layer 120 is fabricated on the substrate 100 by a deposition process;

[0083] In this step, by fabricating a buffer layer 120 on the substrate 100, the surface stress of the base layer 110 can be balanced and optimized, preventing warping of the base layer 110 during fabrication on the glass substrate 900 and ensuring the flatness of the substrate 100 in the flip-chip film. Furthermore, during the use of the flip-chip film, the buffer layer 120 can also provide buffer protection for the components disposed within the flip-chip film. For example, as... Figure 6B As shown, silicon oxide (SiO) or silicon nitride (SiN) can be used as the film material, and a buffer layer 120 with a thickness of 500-1500 Å can be prepared on the substrate 110 by a deposition process so that the buffer layer 120 covers the surface of the substrate 100.

[0084] In addition, such as Figure 6FAs shown, after the metal pin 300 is fabricated, in order to prevent the surface of the metal pin 300 in the flip-chip film from oxidizing and affecting the connection effect and data transmission capability between the metal pin 300 and the metal pad 720 of the IC chip 710, the metal pin 300 needs to be treated by a tinning process so that the surface of the metal pin 300 is covered with a protective layer formed by tin.

[0085] In some embodiments, the second connection portion 320 of the metal pin 300 is fabricated by photolithography and electroplating processes, and then the process further includes removing a barrier layer 500 outside the range of the orthographic projection of the second connection portion 320 on the substrate 100 by photolithography and etching processes.

[0086] Specifically, in order to maintain the thickness of the flip-chip film, a metal mask can be used, and the barrier layer 500 in the non-bonding area around the metal pin 300 can be removed by photolithography and etching processes, that is, the excess barrier layer 500 located outside the range of the orthogonal projection of the second connection portion 320 on the substrate 100 can be etched away.

[0087] In some embodiments, the thickness of the barrier layer 500 is 500-1000 Å; wherein, when fabricating the barrier layer 500, the thickness of the barrier layer 500 can be controlled within the range of 500-1000 Å, such as the barrier layer 500 being 500 Å, 750 Å, or 1000 Å; when the thickness of the barrier layer 500 is set within 500-1000 Å, the metal pin 300 will not be too thick, while also ensuring a good connection between it and the encapsulation layer 400 and the second connection portion 320, thus achieving a good sealing effect.

[0088] In some embodiments, the barrier layer 500 is made of at least one of silicon nitride and silicon oxide. For example, silicon nitride can be used to make the barrier layer 500. By using silicon nitride to make the barrier layer 500, the barrier layer 500 can have a better adhesion effect with the encapsulation layer 400 and the metal pins 300, thereby improving the connection effect of the metal pins 300. At the same time, the barrier layer 500 formed by silicon nitride can seal the gap between the encapsulation layer 400 and the metal pins 300, preventing the metal pins 300 from being corroded by acid during the tinning process, and ensuring that they will not fall off from the flip-chip film.

[0089] Furthermore, after the barrier layer 500 around the second connection portion 320 of the metal pin 300 is etched away using photolithography and mask etching processes, solder paste 800 can be applied to the side of the encapsulation layer 400 away from the substrate 100 using a coating process. This ensures that the solder paste 800 covers the area outside the orthographic projection of the second connection portion 320 onto the substrate 100, even if the solder paste 800 covers non-bonding areas, such as... Figure 6FAs shown; wherein, the soldering solder mask 800 can form a protective layer in the non-bonding area, preventing damage to the encapsulation layer 400 when soldering between the metal pin 300 and the metal pad 720 of the IC driver chip, thereby protecting the layer structure in the flip-chip film. In addition, the soldering solder mask 800 has good adhesion and ductility and will not exert a restraining force on the flip-chip film in a bent state.

[0090] For the flip-chip film in this application, after coating the non-bonding area of ​​the flip-chip film with solder solder mask 800, the IC chip 710 can be bonded using a eutectic bonding process. This securely connects the metal pins 300 on the flip-chip film to the metal pads 720 of the IC chip 710, enabling data transmission between them. Figure 6F As shown; in order to ensure the stability and reliability of data transmission and improve the robustness of IC chip 710 mounting, the metal pad 720 of IC chip 710 can be made of any one or more of the following metal materials: titanium (Ti), copper (Cu), nickel (Ni), platinum (Pt), silver (Ag) and gold (Au), which will not be elaborated here.

[0091] After the IC chip 710 is bonded and soldered, the glass substrate 900 can be peeled off using laser lift-off technology, such as... Figure 6G As shown, this allows the glass substrate 900 to detach from the flip-chip film, thereby completing the fabrication of the flip-chip film.

[0092] It should be noted that the above description describes some embodiments of this application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0093] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in the details for the sake of brevity.

[0094] Furthermore, to simplify the description and discussion, and to avoid obscuring the embodiments of this application, the apparatus may be shown in block diagram form in the provided drawings. This is to avoid making the embodiments of this application difficult to understand, and it also takes into account the fact that the details of the implementation of these block diagram apparatuses are highly dependent on the platform on which the embodiments of this application will be implemented (i.e., these details should be fully within the understanding of those skilled in the art). While specific details (e.g., circuitry) have been set forth to describe exemplary embodiments of this application, it will be apparent to those skilled in the art that the embodiments of this application can be implemented without these specific details or with variations thereof. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0095] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0096] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A flip-chip thin film, characterized in that, include: A substrate on which patterned metal traces are arranged; An encapsulation layer is disposed on the side of the metal trace away from the substrate, and the orthographic projection of the metal trace on the substrate covers the orthographic projection of the metal trace on the substrate. Metal pins are disposed on the side of the encapsulation layer away from the substrate and are fixedly connected to the side of the metal trace away from the substrate. A barrier layer is disposed on the side of the encapsulation layer away from the substrate and is connected to the metal pins; The metal pin includes a first connection portion and a second connection portion connected together. The first connection portion is fixedly connected to the side of the metal trace away from the substrate. The orthographic projection of the barrier layer on the substrate surrounds the orthographic projection of the first connection portion on the substrate. It also includes a first contact surface disposed on the side of the second connection portion near the substrate. The second connection portion is connected to the side of the barrier layer away from the substrate through the first contact surface. The barrier layer is configured to seal the gap between the metal pin and the package layer, so that a uniform tin protective layer is formed on the surface of the second connection portion during the tinning process, so as to prevent the acid solution used in the tinning process from corroding the surface of the first connection portion and its connection with the metal trace.

2. The flip-chip thin film according to claim 1, characterized in that, The thickness of the barrier layer is 500-1000 Å.

3. The flip-chip thin film according to claim 1, characterized in that, The barrier layer is made of at least one of silicon nitride and silicon oxide.

4. The flip-chip thin film according to claim 1, characterized in that, The metal pins are arranged in an array on the packaging layer.

5. The flip-chip thin film according to claim 1, characterized in that, Also includes: The first adapter hole is disposed on the encapsulation layer, and its orthogonal projection on the substrate is located within the orthogonal projection of the metal trace on the substrate. The first connection portion is located within the first adapter hole. The second adapter hole is disposed on the barrier layer, and its orthogonal projection on the substrate covers the orthogonal projection of the first adapter hole on the substrate. The first connection portion is located inside the second adapter hole.

6. The flip-chip thin film according to claim 1, characterized in that, The metal pins also include: The second contact surface is disposed on the side of the second connection portion away from the substrate, and its orthographic projection on the substrate is located within the orthographic projection of the first contact surface on the substrate.

7. The flip-chip thin film according to claim 1, characterized in that, Also includes: The soldering green oil is disposed on the side of the encapsulation layer away from the substrate, and its orthogonal projection on the substrate is outside the range of the orthogonal projection of the second connection portion on the substrate.

8. A display device, characterized in that, Including the flip-chip film as described in any one of claims 1-7.

9. A method for preparing a flip-chip thin film, suitable for preparing the flip-chip thin film as described in any one of claims 1-7, characterized in that, The preparation method includes: A substrate is provided, on which metal traces and a packaging layer are sequentially formed, and a first adapter hole is fabricated on the packaging layer by photolithography. A barrier layer is formed on the side of the encapsulation layer away from the substrate by a deposition process, and a second adapter hole communicating with the first adapter hole is made on the barrier layer by a photolithography and etching process. The first connection portion of the metal pin is fabricated sequentially in the first and second adapter holes by a seed layer deposition process, and the second connection portion of the metal pin is fabricated by photolithography and electroplating processes, and the second connection portion of the metal pin is connected to the barrier layer.

10. The preparation method according to claim 9, characterized in that, This also includes: The barrier layer outside the range of the orthogonal projection of the second connection portion on the substrate is removed by photolithography and etching processes.

11. The preparation method according to claim 9, characterized in that, in, The thickness of the barrier layer is 500-1000 Å.

12. The preparation method according to claim 9, characterized in that, in, The barrier layer is made of at least one of silicon nitride and silicon oxide.

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