A packaging method and packaging structure for a piezoelectric printed chip

Abstract

This invention discloses a packaging method and structure for a piezoelectric printed chip. The packaging method involves embedding metal balls on each pin of the piezoelectric printed chip. The piezoelectric printed chip includes a substrate and multiple chip pins, with at least some pins having different distances from the substrate on the side furthest from it. Before lamination, the thickness of the metal balls on the chip pins is greater than the maximum height difference, which is the maximum difference in distance between the sides of different chip pins furthest from the substrate. The circuit endpoints of a printed circuit board are aligned with the corresponding chip pins. The aligned printed circuit board and the piezoelectric printed chip are then laminated, connecting each circuit endpoint to its corresponding chip pin, ensuring that the distance between the metal balls on each chip pin and the substrate is the same on the side furthest from it after lamination. This invention improves the reliability of the piezoelectric printed chip packaging structure and increases the packaging yield.

Description

Technical Field

[0001] This invention relates to the field of printing technology, and in particular to a packaging method and packaging structure for a piezoelectric printing chip. Background Technology

[0002] Inkjet printing technology is becoming increasingly important in industrial and consumer printing, which has placed new demands on the packaging of piezoelectric printing chips.

[0003] However, due to their extremely thin thickness and flexibility, piezoelectric printed chips make it difficult to control the height of the protrusions formed by solder melting in traditional flip-chip packaging, failing to meet the requirements of ultra-thin packaging. In existing technologies, anisotropic conductive adhesives are often used to connect chip electrodes and pads to solve the problem of high-density pin interconnection. However, this method relies excessively on a single material system, and the small size of the conductive tin particles within the adhesive makes it extremely sensitive to the flatness of the chip surface, easily leading to insufficient bonding, poor contact, and low reliability of the packaging structure. Summary of the Invention

[0004] This invention provides a packaging method and packaging structure for piezoelectric printed chips, so as to improve the reliability of the packaging structure of piezoelectric printed chips and improve the packaging yield of piezoelectric printed chips.

[0005] In a first aspect, embodiments of the present invention provide a packaging method for a piezoelectric printed chip, comprising: Metal balls are implanted on each chip pin of the piezoelectric printed chip; wherein, the piezoelectric printed chip includes a substrate and multiple chip pins, and the multiple chip pins are located on the same side of the piezoelectric printed chip; at least some of the chip pins are at different distances from the substrate on the side away from the substrate, and the thickness of the metal balls on the chip pins before pressing is greater than the maximum height difference, the maximum height difference being the maximum difference in distance between the side of different chip pins away from the substrate and the substrate; Align the circuit endpoints of the printed circuit board with the corresponding chip pins; The aligned printed circuit board is pressed together with the piezoelectric printed chip, so that each circuit endpoint is connected to the corresponding chip pin, and after pressing, the metal ball on each chip pin is at the same distance from the substrate on the side away from the substrate.

[0006] Furthermore, the diameter of the metal ball on the chip pin before lamination is greater than the maximum height difference; the step of laminating the aligned printed circuit board with the piezoelectric printed chip, so that each circuit endpoint is connected to the corresponding chip pin, and after lamination, the side of the metal ball on each chip pin away from the substrate is at the same distance from the substrate, includes: The aligned printed circuit board and the piezoelectric printed chip are pressed together under preset pressure and preset temperature, causing the metal balls on each chip pin to deform, so that each circuit endpoint is connected to the corresponding chip pin, and the total thickness of the metal balls on each chip pin and the corresponding chip pin is the same.

[0007] Furthermore, the chip pins include multiple functional pins and ground pins. The side of each functional pin away from the substrate is at the same distance from the substrate, while the distance between the side of the functional pin away from the substrate and the substrate is different from the distance between the side of the ground pin away from the substrate and the substrate. The step of pressing the aligned printed circuit board to the piezoelectric printed chip, connecting each circuit endpoint to the corresponding chip pin, and ensuring that the metal ball on each chip pin is at the same distance from the substrate on the side furthest from the substrate after pressing, includes: The aligned printed circuit board and the piezoelectric printed chip are pressed together under preset pressure and preset temperature, so that each circuit endpoint is connected to the corresponding chip pin. The distance between the metal ball on the functional pin away from the substrate and the substrate is the same as the distance between the metal ball on the ground pin away from the substrate and the substrate.

[0008] Furthermore, the printed circuit board is provided with an upper alignment mark, and the piezoelectric printing chip is provided with a lower alignment mark. Aligning the circuit endpoints of the printed circuit board with the corresponding chip pins includes: Move the printed circuit board until the projection of the upper alignment mark on the piezoelectric printed chip overlaps with the lower alignment mark, so that the circuit endpoints of the printed circuit board are aligned with the corresponding chip pins.

[0009] Furthermore, the aligned printed circuit board is pressed together with the piezoelectric printed chip, so that each circuit endpoint is connected to the corresponding chip pin, and after pressing, the metal ball on each chip pin is at the same distance from the substrate on the side away from the substrate, including: The aligned printed circuit board and the piezoelectric printed chip are pressed together under preset pressure and preset temperature, so that each circuit endpoint is connected to the corresponding chip pin, and the distance between each circuit endpoint and the substrate is the same.

[0010] Furthermore, the preset temperature includes 300℃-400℃, and the preset pressure includes 0.4MPa-0.6MPa; The step of pressing the aligned printed circuit board and the piezoelectric printed chip together under a preset pressure and a preset temperature includes: The aligned printed circuit board and the piezoelectric printed chip are heated to 300℃-400℃, and a pressure of 0.4MPa-0.6MPa is applied to the printed circuit board.

[0011] Furthermore, after pressing the aligned printed circuit board and the piezoelectric printing chip together, the process further includes: Apply adhesive to the connection points between each circuit endpoint and the corresponding chip pin; The adhesive is then cured.

[0012] Furthermore, the metal balls include gold balls, and the embedding of metal balls on each of the chip pins includes: Gold wires are melted onto the chip pins using a wire bonding process to form gold balls embedded on the chip pins.

[0013] Secondly, embodiments of the present invention also provide a packaging structure for a piezoelectric printed chip, wherein the packaging structure is formed by a packaging method for a piezoelectric printed chip according to any embodiment of the present invention, and the packaging structure includes: A piezoelectric printed chip includes a substrate and a plurality of chip pins, wherein the plurality of chip pins are located on the same side of the piezoelectric printed chip; wherein, at least some of the chip pins are located at a different distance from the substrate on the side away from the substrate; A printed circuit board, wherein each circuit endpoint on the printed circuit board is connected to the corresponding chip pin by a metal ball embedded on the chip pin, and the side of the metal ball on each chip pin away from the substrate is at the same distance from the substrate.

[0014] Optionally, the metal ball includes a gold ball, the chip pins include multiple functional pins and ground pins, the functional pins include a first top electrode layer, a piezoelectric material layer and a first bottom electrode layer stacked together, and the ground pins include a second bottom electrode layer; The distance between the side of each functional pin away from the substrate and the substrate is the same, but the distance between the side of the functional pin away from the substrate and the substrate is different from the distance between the side of the ground pin away from the substrate and the substrate. The distance between the metal ball on the functional pin and the substrate on the side away from the substrate is the same as the distance between the metal ball on the ground pin and the substrate on the side away from the substrate.

[0015] This invention provides a packaging method and structure for a piezoelectric printed chip. Metal balls are implanted on each pin of the piezoelectric printed chip. The piezoelectric printed chip includes a substrate and multiple chip pins located on the same side of the chip. At least some chip pins have different distances from the substrate on the side furthest from the substrate. Before bonding, the thickness of the metal balls on the chip pins is greater than the maximum height difference, which is the maximum difference in distance between the sides of different chip pins furthest from the substrate. To avoid poor electrical connections and open circuits in the packaging structure due to height differences between different chip pins during packaging, the printing process is improved. The circuit endpoints of the circuit board are aligned with the corresponding chip pins. The aligned printed circuit board and the piezoelectric printed chip are then pressed together. The large metal ball deforms after pressing, allowing each circuit endpoint to connect with the corresponding chip pin. After pressing, the side of the metal ball on each chip pin away from the substrate is at the same distance from the substrate, ensuring that each circuit endpoint of the printed circuit board and the corresponding chip pin can make full contact and achieve effective electrical connection. This overcomes the influence of different chip pin heights caused by process reasons on the piezoelectric printed chip, improves the reliability of the piezoelectric printed chip packaging structure, and increases the packaging yield of the piezoelectric printed chip. Attached Figure Description

[0016] Figure 1 A flowchart illustrating a packaging method for a piezoelectric printed chip provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the piezoelectric printing chip provided in an embodiment of the present invention; Figure 3 A flowchart illustrating another packaging method for a piezoelectric printed chip provided in an embodiment of the present invention; Figure 4 A schematic diagram of the packaging structure of a piezoelectric printing chip provided in an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the alignment of a printed circuit board and a piezoelectric printing chip according to an embodiment of the present invention. Figure 6 This is an enlarged schematic diagram of region A during the alignment of the printed circuit board and the piezoelectric printing chip according to an embodiment of the present invention. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0018] In related technologies, the packaging of piezoelectric printed chips relies on anisotropic conductive adhesives to connect the chip electrodes to the pads. However, the maximum size of the tin particles in the anisotropic conductive adhesive is 5µm. If the particle size is too large, it reduces the number of particles that contact each electrode and also easily causes short circuits due to contact between conductive particles on adjacent electrodes. Therefore, it is not possible to further increase the size of the tin particles in the anisotropic conductive adhesive. For uneven piezoelectric printed chips, such as those with height differences between chip leads, if the height difference is greater than the size of the tin particles, the anisotropic conductive adhesive may fail to bond properly, resulting in some chip leads not effectively connecting to the pads. Furthermore, because the tin particles in the anisotropic conductive adhesive are too small, there may be instances where the chip leads and pads do not contact simultaneously during bonding, leading to poor electrical connections. Additionally, random movement of the tin particles in the anisotropic conductive adhesive during packaging can also cause poor electrical connections, resulting in low reliability and low yield of the piezoelectric printed chip packaging structure.

[0019] To address the aforementioned technical problems, embodiments of the present invention provide a packaging method for a piezoelectric printed chip. Figure 1 A flowchart illustrating a piezoelectric printed chip packaging method provided in an embodiment of the present invention is shown below. Figure 1 As shown, the packaging method for piezoelectric printed chips includes: S110. Metal balls are implanted on each chip pin of the piezoelectric printed chip; wherein, the piezoelectric printed chip includes a substrate and multiple chip pins, and the multiple chip pins are located on the same side of the piezoelectric printed chip; at least some chip pins have different distances from the substrate on the side away from the substrate, and the thickness of the metal balls on the chip pins before pressing is greater than the maximum height difference, the maximum height difference being the maximum difference in distance between the side of different chip pins away from the substrate and the substrate.

[0020] in, Figure 2 This is a schematic diagram of the structure of the piezoelectric printing chip provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the piezoelectric printed chip 100 includes a substrate 110 and multiple chip pins 120. The chip pins 120 are disposed on the same side of the substrate 110, and some chip pins 120 have different heights. The maximum difference in distance between the side of different chip pins 120 furthest from the substrate 110 and the substrate 110 is the maximum height difference H. The metal ball can be made of a highly ductile metal, such as gold, platinum, or silver, to allow the pressed metal ball to undergo controlled plastic deformation, connecting the printed circuit board and the piezoelectric printed chip.

[0021] Specifically, after fixing the piezoelectric printing chip 100, metal balls can be implanted on each chip pin 120 of the piezoelectric printing chip 100. Before pressing, the height of a single metal ball is set to be greater than the maximum height difference H between the chip pins 120, ensuring that even the lowest chip pin 120 in the piezoelectric printing chip 100, the total height of the top of the chip pin 120 plus the metal ball can exceed that of the highest chip pin 120, providing sufficient deformation margin for subsequent coplanar pressing.

[0022] S120. Align the circuit endpoints of the printed circuit board with the corresponding chip pins.

[0023] Specifically, the printed circuit board can be made of polyimide material. With the assistance of an optical vision system, the printed circuit board with circuit endpoints can be precisely aligned with the piezoelectric printed chip 100. The circuit endpoints of the printed circuit board are also the pads of the printed circuit board. Each circuit endpoint on the printed circuit board is precisely aligned with its corresponding chip pin in the vertical projection direction so that the chip pin 120 of the piezoelectric printed chip 100 and the circuit endpoints of the printed circuit board can be connected by a metal ball.

[0024] S130. Press the aligned printed circuit board with the piezoelectric printing chip so that each circuit endpoint is connected to the corresponding chip pin, and after pressing, the metal ball on each chip pin is at the same distance from the substrate on the side away from the substrate.

[0025] Specifically, the printed circuit board is pressed towards the piezoelectric printed chip 100. Under the action of the pressing force, the metal balls on each chip pin 120 undergo controlled plastic deformation. Since the initial height of the metal balls compensates for the height difference of the chip pins 120, after pressing, the side of the metal ball on each chip pin 120 away from the substrate 110 is at the same distance from the substrate 110. The chip pins 120, which originally had different heights, achieve complete coplanarization of the contact interface with the printed circuit board through the differentiated compression of the metal balls. This results in a uniform and reliable electrical connection between each circuit endpoint and the corresponding chip pin 120. This solves the technical problem of low reliability and low packaging yield of piezoelectric printed chips when using anisotropic conductive adhesive for encapsulation in the prior art. It ensures that each circuit endpoint of the printed circuit board can fully contact and effectively connect with the corresponding chip pin 120, thereby overcoming the influence of different chip pin heights 120 caused by process reasons on the piezoelectric printed chip, improving the reliability of the piezoelectric printed chip packaging structure, and improving the packaging yield of the piezoelectric printed chip.

[0026] This invention provides a packaging method for a piezoelectric printed chip. Metal balls are implanted on each pin of the piezoelectric printed chip. The piezoelectric printed chip includes a substrate and multiple chip pins located on the same side of the chip. At least some chip pins have different distances from the substrate on the side furthest from the substrate. Before bonding, the thickness of the metal balls on the chip pins is greater than the maximum height difference, which is the maximum difference in distance between the sides of different chip pins furthest from the substrate. To avoid poor electrical connections and open circuits in the packaging structure due to height differences between different chip pins during packaging, the method involves printing metal balls onto the chip pins. The circuit endpoints of the circuit board are aligned with the corresponding chip pins. The aligned printed circuit board and the piezoelectric printed chip are then pressed together. The large metal ball deforms after pressing, allowing each circuit endpoint to connect with the corresponding chip pin. After pressing, the side of the metal ball on each chip pin away from the substrate is at the same distance from the substrate, ensuring that each circuit endpoint of the printed circuit board and the corresponding chip pin can make full contact and achieve effective electrical connection. This overcomes the influence of different chip pin heights caused by process reasons on the piezoelectric printed chip, improves the reliability of the piezoelectric printed chip packaging structure, and increases the packaging yield of the piezoelectric printed chip.

[0027] In an embodiment of the present invention, reference is made to Figure 2 If the metal ball on the chip pin 120 can be spherical, then the thickness of the metal ball on the chip pin 120 before pressing is equal to the diameter of the metal ball. By setting the diameter of the metal ball on the chip pin 120 before pressing to be greater than the maximum height difference, it can be further ensured that the side of the metal ball on each chip pin 120 away from the substrate 110 after pressing is the same as the distance from the substrate 110, ensuring that each circuit endpoint of the printed circuit board can fully contact the corresponding chip pin 120 for effective electrical connection.

[0028] To further achieve reliable packaging of piezoelectric printed chips, this invention also provides another packaging method for piezoelectric printed chips. Figure 3 A flowchart of another piezoelectric printed chip packaging method provided by an embodiment of the present invention is shown below. Figure 3 As shown, the packaging method for piezoelectric printed chips includes: S210. Metal balls are implanted on each chip pin of the piezoelectric printed chip; wherein, the piezoelectric printed chip includes a substrate and multiple chip pins, and the multiple chip pins are located on the same side of the piezoelectric printed chip; at least some chip pins have different distances from the substrate on the side away from the substrate, and the thickness of the metal balls on the chip pins before pressing is greater than the maximum height difference, and the maximum height difference is the maximum difference in distance between the side of different chip pins away from the substrate and the substrate.

[0029] S220. Align the circuit endpoints of the printed circuit board with the corresponding chip pins.

[0030] S230. Under preset pressure and preset temperature, the aligned printed circuit board and the piezoelectric printed chip are pressed together, so that the metal balls on each chip pin are deformed, so that each circuit endpoint is connected to the corresponding chip pin, and the total thickness of the metal balls on each chip pin and the corresponding chip pin is the same.

[0031] Specifically, by applying preset pressure and temperature to the printed circuit board, the metal balls on each chip pin 120 deform, compensating for the height differences of each chip pin 120. Under pressure, the metal balls also conduct electricity, connecting each circuit endpoint to the corresponding chip pin 120, thus achieving electrical connection between the chip pin 120 and the circuit endpoints of the printed circuit board. In this process, the metal balls can be gold balls, which, as the electrical connection material between the chip and the flexible circuit board, offer advantages such as reliable conductivity and long service life. Simultaneously, this packaging method is simple, efficient, and low-cost. This packaging structure can address the impact of varying chip pin heights 120 caused by process variations on thin-film piezoelectric printed chips, improving packaging reliability and yield.

[0032] S240. Apply glue to the connection points between each circuit endpoint and the corresponding chip pin.

[0033] Specifically, Figure 4 This is a schematic diagram of the packaging structure of a piezoelectric printing chip provided in an embodiment of the present invention, as shown below. Figure 4 As shown, the connection points between each circuit endpoint of the printed circuit board 200 and the corresponding chip pin 120 constitute the connection area 400 between the printed circuit board 200 and the piezoelectric printed chip 120. Although the metal ball 300 can also achieve electrical connection between the printed circuit board 200 and the piezoelectric printed chip 100, it cannot go further. In order to further fix the connection between the printed circuit board 200 and the piezoelectric printed chip 100, glue can be applied to the connection area 400 between the printed circuit board 200 and the piezoelectric printed chip 100 so that the space between the printed circuit board 200 and the piezoelectric printed chip 100 is filled with glue.

[0034] S250, cure the adhesive.

[0035] Specifically, the adhesive cures after being heated and cooled. After curing, the connection between the printed circuit board 200 and the piezoelectric printed chip 100 is more secure, and the connection between the metal ball 300 and the printed circuit board 200 or the piezoelectric printed chip 100 is prevented from falling off, thereby further improving the reliability of the piezoelectric printed chip packaging structure.

[0036] In some embodiments of the present invention, the preset temperature includes 300℃-400℃, and the preset pressure includes 0.4MPa-0.6MPa.

[0037] The aligned printed circuit board and piezoelectric printed chip are pressed together under preset pressure and temperature, including: The aligned printed circuit board and piezoelectric printed chip are heated to 300℃-400℃, and a pressure of 0.4MPa-0.6MPa is applied to the printed circuit board.

[0038] Specifically, the aligned printed circuit board 200 and piezoelectric printed chip 100 are heated to 300℃-400℃, and a pressure of 0.4MPa-0.6MPa is applied to the printed circuit board 200. The direction of the pressure application is that the printed circuit board 200 is facing the piezoelectric printed chip 100.

[0039] In some embodiments of the present invention, reference is made to Figure 2 and Figure 4 The chip pin 120 includes multiple functional pins 121 and ground pins 122. The side of each functional pin 121 away from the substrate 110 is at the same distance from the substrate 110. The distance between the side of the functional pin 121 away from the substrate 110 and the substrate 110 is different from the distance between the side of the ground pin 122 away from the substrate 121 and the substrate 110.

[0040] Specifically, each independent functional electrode 121 is electrically connected to a unique corresponding circuit terminal on the printed circuit board 200, ensuring that the external driving circuit can apply an independent control signal to each functional electrode 121 to achieve precise control of the droplet ejection of the piezoelectric printing chip. There is a height difference between the functional pin 121 and the ground pin 122; during packaging, the packaging problem caused by this height difference needs to be addressed.

[0041] In this embodiment of the invention, the aligned printed circuit board and the piezoelectric printed chip are pressed together, so that each circuit endpoint is connected to the corresponding chip pin, and after pressing, the metal ball on each chip pin is at the same distance from the substrate on the side away from the substrate, including: Under preset pressure and temperature, the aligned printed circuit board and piezoelectric printed chip are pressed together, so that each circuit endpoint is connected to the corresponding chip pin. The distance between the metal ball on the functional pin away from the substrate and the substrate is the same as the distance between the metal ball on the ground pin away from the substrate and the substrate.

[0042] Specifically, after the aligned printed circuit board 200 and piezoelectric printed chip 100 are pressed together under preset pressure and temperature, each circuit endpoint is connected to the corresponding chip pin 120. The metal balls on each functional pin 120 deform after pressing. The distance between the side of the metal ball on functional pin 121 away from the substrate 110 and the substrate 110 is the same as the distance between the side of the metal ball on ground pin 122 away from the substrate 110 and the substrate 110. The functional pins 121 and ground pins 122, which originally had different heights, achieve complete convergence of their contact interfaces with the printed circuit board through the differentiated compression of the metal balls. By surface-mounting the circuit, a uniform and reliable electrical connection is formed between each circuit endpoint and the functional pin 121 or ground pin 122. This solves the technical problem of low reliability and low yield of piezoelectric printed chips when using anisotropic conductive adhesive for encapsulation in the prior art. It ensures that each circuit endpoint of the printed circuit board can make full contact with the corresponding functional pin 121 or ground pin 122 and form an effective electrical connection. This overcomes the influence of the different heights of the functional pin 121 and ground pin 122 on the piezoelectric printed chip due to process reasons, improves the reliability of the piezoelectric printed chip's encapsulation structure, and improves the packaging yield of the piezoelectric printed chip.

[0043] In some embodiments of the present invention Figure 5 This is a schematic diagram illustrating the alignment of a printed circuit board and a piezoelectric printing chip according to an embodiment of the present invention. Figure 6 This is an enlarged schematic diagram of region A during the alignment of the printed circuit board and the piezoelectric printing chip according to an embodiment of the present invention, as shown below. Figure 5 and Figure 6 As shown, the printed circuit board 200 is provided with an upper alignment mark 201, and the piezoelectric printing chip 100 is provided with a lower alignment mark 101.

[0044] Aligning the circuit endpoints of the printed circuit board with the corresponding chip pins includes: Move the printed circuit board until the projection of the upper alignment mark on the piezoelectric printed chip overlaps with the lower alignment mark, thus aligning the circuit endpoints of the printed circuit board with the corresponding chip pins.

[0045] The printed circuit board 200 may have multiple upper alignment marks 201, and the piezoelectric printing chip 100 may have multiple lower alignment marks 101 corresponding to the upper alignment marks 201. For example, the printed circuit board 200 and the piezoelectric printing chip 100 are provided with upper alignment marks 201 on both the left and right sides for alignment, and the piezoelectric printing chip 100 may have lower alignment marks 101 corresponding to the upper alignment marks 201, to prevent the position of the printed circuit board 200 from shifting during alignment, so as to further improve the alignment accuracy between the circuit endpoints of the printed circuit board 200 and the corresponding chip pins 120, and further improve the reliability of the package structure.

[0046] Specifically, by moving the printed circuit board 200 until the projection of the upper alignment mark 201 on the piezoelectric printed chip 100 overlaps with the lower alignment mark 101, the circuit endpoints of the printed circuit board 200 are aligned with the corresponding chip pins 120, preventing any misalignment between the circuit endpoints of the printed circuit board 200 and the corresponding chip pins 120.

[0047] In this embodiment of the invention, the metal ball includes a gold ball, and metal balls are implanted on each chip pin, including: Gold wires are melted onto the chip pins using a wire bonding process, forming gold balls embedded on the chip pins.

[0048] Specifically, the metal spheres include gold spheres. Gold spheres serve as electrical connection materials between the printed circuit board 200 and the piezoelectric printed chip 100. They have the advantages of reliable conductivity and long service life. Through wire bonding technology, gold wires can be melted onto each chip pin 120 to form gold spheres embedded on each chip pin 120. Adjacent gold spheres can be spaced at a preset distance.

[0049] This invention provides a packaging method for piezoelectric printed chips. By implanting gold balls into the chip pins of the piezoelectric printed chip, the gold balls can undergo controlled plastic deformation after lamination, effectively electrically connecting the printed circuit board and the piezoelectric printed chip. This overcomes the influence of different chip pin heights caused by process reasons on the piezoelectric printed chip, improving the reliability and packaging yield of the piezoelectric printed chip packaging structure. This packaging method is simple, efficient, and low-cost, does not rely on special equipment, and has no production capacity limitations.

[0050] This invention also provides a packaging structure for a piezoelectric printed chip, which is formed by the packaging method of the piezoelectric printed chip according to any embodiment of this invention, such as... Figure 4 As shown, the packaging structure of the piezoelectric printing chip includes: The piezoelectric printed chip 100 includes a substrate 110 and a plurality of chip pins 120, the plurality of chip pins 120 being located on the same side of the piezoelectric printed chip 100; wherein, the piezoelectric printed chip 100 includes a substrate 110 and a plurality of chip pins 120, the plurality of chip pins 120 being located on the same side of the piezoelectric printed chip 100; at least some of the chip pins 120 being at a different distance from the substrate 110 on the side away from the substrate 110.

[0051] The printed circuit board 200 has circuit endpoints on it connected to corresponding chip pins 120 via metal balls 300 embedded on the chip pins. The side of the metal ball 300 on each chip pin 120 that is away from the substrate 110 is at the same distance from the substrate 110.

[0052] Specifically, the packaging structure of the piezoelectric printed chip is formed by pressing the printed circuit board 200 and the piezoelectric printed chip 100 together. The printed circuit board 200 is pressed toward the piezoelectric printed chip 100. Under the action of the pressing force, the metal balls 300 on each chip pin 120 undergo controlled plastic deformation. Because the initial height of the metal ball 300 compensates for the height difference of the chip pins 120, after lamination, the side of the metal ball on each chip pin 120 away from the substrate 110 is at the same distance from the substrate 110. The chip pins 120, which originally had different heights, are now at the same distance from the substrate 110 on the side of the metal ball 300 away from the substrate 110 through the differentiated compression of the metal ball 300. This achieves complete coplanarization of the contact interface with the printed circuit board 200, thereby forming a uniform and reliable electrical connection between each circuit endpoint and the corresponding chip pin 120. This solves the technical problem of low reliability and low packaging yield of piezoelectric printed chips when using anisotropic conductive adhesive for encapsulation in the prior art. It ensures that each circuit endpoint of the printed circuit board can make full contact with the corresponding chip pin 120 and form an effective electrical connection, thereby overcoming the influence of different chip pin heights 120 caused by process reasons on the piezoelectric printed chip, improving the reliability of the piezoelectric printed chip packaging structure, and improving the packaging yield of the piezoelectric printed chip.

[0053] The piezoelectric printing chip packaging structure provided in this embodiment of the invention is formed by the piezoelectric printing chip packaging method of any of the above embodiments, and has the beneficial effects of the piezoelectric printing chip packaging method proposed in the above embodiments, which will not be repeated here.

[0054] In this embodiment of the invention, the metal ball 300 includes a gold ball, the chip pin 120 includes a plurality of functional pins 121 and ground pins 122, the functional pins 121 include a first top electrode layer 1211, a piezoelectric material layer 1212 and a first bottom electrode layer 1213 stacked together, and the ground pins 122 include a second bottom electrode layer 1221.

[0055] The side of each functional pin 121 away from the substrate 110 is at the same distance from the substrate 110, but the distance between the side of the functional pin 121 away from the substrate and the substrate 110 is different from the distance between the side of the ground pin 122 away from the substrate 110 and the substrate 110.

[0056] The distance between the metal ball 300 on the side away from the substrate 110 on the functional pin 121 and the substrate 110 is the same as the distance between the metal ball 300 on the side away from the substrate 110 on the ground pin 122.

[0057] The connection area 400 between the printed circuit board 200 and the piezoelectric printed chip 100 is also provided with cured adhesive to prevent the metal ball 300 from falling off, thereby further improving the reliability of the piezoelectric printed chip's packaging structure.

[0058] Specifically, such as Figure 4 As shown, the functional pin 121 is composed of a first top electrode layer 1211, a piezoelectric material layer 1212, and a first bottom electrode layer 1213. The first top electrode layer 1211, the piezoelectric material layer 1212, and the first bottom electrode layer 1213 are integrally formed. The piezoelectric material layer 1212 is made of piezoelectric ceramic material, such as lead zirconate titanate (chemical formula Pb(Zr,Ti)O3, abbreviated as PZT). The ground pin 122 includes a second bottom electrode layer 1221. The first top electrode layer 1211, the first bottom electrode layer 1213, and the second bottom electrode layer 1221 can all be made of platinum. The distance between the side of the functional pin 121 away from the substrate and the substrate 110 is different from the distance between the side of the ground pin 122 away from the substrate 110 and the substrate 110. By setting the metal ball 300, after lamination, the distance between the side of the metal ball 300 on the functional pin 121 away from the substrate 110 and the substrate 110 is the same as the distance between the side of the metal ball 300 on the ground pin 122 away from the substrate 110. This further overcomes the influence of different chip pin heights 120 caused by process reasons on the piezoelectric printed chip, improves the reliability of the piezoelectric printed chip packaging structure, and improves the packaging yield of the piezoelectric printed chip.

[0059] This invention provides a packaging structure for a piezoelectric printed chip. Metal balls are implanted on each chip pin of the piezoelectric printed chip, connecting each circuit endpoint to its corresponding chip pin. After lamination, the metal balls on each chip pin are at the same distance from the substrate on the side furthest from the substrate. This ensures that each circuit endpoint of the printed circuit board can fully contact its corresponding chip pin for effective electrical connection. This overcomes the influence of varying chip pin heights caused by process limitations on the piezoelectric printed chip, improving the reliability of the packaging structure and increasing the packaging yield of the piezoelectric printed chip.

[0060] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method of packaging a piezoelectric printing chip, characterized by, include: Metal balls are implanted on each chip pin of the piezoelectric printed chip; wherein, the piezoelectric printed chip includes a substrate and multiple chip pins, and the multiple chip pins are located on the same side of the piezoelectric printed chip; at least some of the chip pins are at different distances from the substrate on the side away from the substrate, and the thickness of the metal balls on the chip pins before pressing is greater than the maximum height difference, the maximum height difference being the maximum difference in distance between the side of different chip pins away from the substrate and the substrate; Align the circuit endpoints of the printed circuit board with the corresponding chip pins; The aligned printed circuit board is pressed together with the piezoelectric printed chip, so that each circuit endpoint is connected to the corresponding chip pin, and after pressing, the metal ball on each chip pin is at the same distance from the substrate on the side away from the substrate.

2. The method of packaging a piezoelectric printing chip according to claim 1, wherein, Before lamination, the diameter of the metal ball on the chip pin is greater than the maximum height difference; the step of laminating the aligned printed circuit board with the piezoelectric printed chip, connecting each circuit endpoint to the corresponding chip pin, and ensuring that the side of the metal ball on each chip pin away from the substrate after lamination is at the same distance from the substrate, includes: The aligned printed circuit board and the piezoelectric printed chip are pressed together under preset pressure and preset temperature, causing the metal balls on each chip pin to deform, so that each circuit endpoint is connected to the corresponding chip pin, and the total thickness of the metal balls on each chip pin and the corresponding chip pin is the same.

3. The method of packaging a piezoelectric printing chip according to claim 1, wherein, The chip pins include multiple functional pins and ground pins. The side of each functional pin away from the substrate is at the same distance from the substrate, while the distance between the side of the functional pin away from the substrate and the substrate is different from the distance between the side of the ground pin away from the substrate. The step of pressing the aligned printed circuit board to the piezoelectric printed chip, connecting each circuit endpoint to the corresponding chip pin, and ensuring that the metal ball on each chip pin is at the same distance from the substrate on the side furthest from the substrate after pressing, includes: The aligned printed circuit board and the piezoelectric printed chip are pressed together under preset pressure and preset temperature, so that each circuit endpoint is connected to the corresponding chip pin. The distance between the metal ball on the functional pin away from the substrate and the substrate is the same as the distance between the metal ball on the ground pin away from the substrate and the substrate.

4. The packaging method for a piezoelectric printed chip according to claim 1, characterized in that, The printed circuit board has an upper alignment mark, and the piezoelectric printing chip has a lower alignment mark. Aligning the circuit endpoints of the printed circuit board with the corresponding chip pins includes: Move the printed circuit board until the projection of the upper alignment mark on the piezoelectric printed chip overlaps with the lower alignment mark, so that the circuit endpoints of the printed circuit board are aligned with the corresponding chip pins.

5. The packaging method for a piezoelectric printed chip according to claim 1, characterized in that, The aligned printed circuit board is pressed together with the piezoelectric printed chip, so that each circuit terminal is connected to the corresponding chip pin, and after pressing, the metal ball on each chip pin is at the same distance from the substrate on the side away from the substrate, including: The aligned printed circuit board and the piezoelectric printed chip are pressed together under preset pressure and preset temperature, so that each circuit endpoint is connected to the corresponding chip pin, and the distance between each circuit endpoint and the substrate is the same.

6. The packaging method for a piezoelectric printed chip according to claim 5, characterized in that, The preset temperature includes 300℃-400℃, and the preset pressure includes 0.4MPa-0.6MPa; The step of pressing the aligned printed circuit board and the piezoelectric printed chip together under a preset pressure and a preset temperature includes: The aligned printed circuit board and the piezoelectric printed chip are heated to 300℃-400℃, and a pressure of 0.4MPa-0.6MPa is applied to the printed circuit board.

7. The packaging method for a piezoelectric printed chip according to claim 1, characterized in that, After pressing the aligned printed circuit board and the piezoelectric printed chip together, the process further includes: Apply adhesive to the connection points between each circuit endpoint and the corresponding chip pin; The adhesive is then cured.

8. The packaging method for a piezoelectric printed chip according to any one of claims 1-7, characterized in that, The metal spheres include gold spheres, and the embedding of metal spheres on each of the chip pins includes: Gold wires are melted onto the chip pins using a wire bonding process to form gold balls embedded on the chip pins.

9. A packaging structure for a piezoelectric printed chip, characterized in that, The packaging structure of the piezoelectric printing chip is formed by the packaging method of the piezoelectric printing chip according to any one of claims 1-8, and the packaging structure of the piezoelectric printing chip includes: A piezoelectric printed chip includes a substrate and a plurality of chip pins, wherein the plurality of chip pins are located on the same side of the piezoelectric printed chip; wherein, at least some of the chip pins are located at a different distance from the substrate on the side away from the substrate; A printed circuit board, wherein each circuit endpoint on the printed circuit board is connected to the corresponding chip pin by a metal ball embedded on the chip pin, and the side of the metal ball on each chip pin away from the substrate is at the same distance from the substrate.

10. The packaging structure of the piezoelectric printed chip according to claim 9, characterized in that, The metal ball includes a gold ball, the chip pins include multiple functional pins and ground pins, the functional pins include a first top electrode layer, a piezoelectric material layer and a first bottom electrode layer stacked together, and the ground pins include a second bottom electrode layer; The distance between the side of each functional pin away from the substrate and the substrate is the same, but the distance between the side of the functional pin away from the substrate and the substrate is different from the distance between the side of the ground pin away from the substrate and the substrate. The distance between the metal ball on the functional pin and the substrate on the side away from the substrate is the same as the distance between the metal ball on the ground pin and the substrate on the side away from the substrate.

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