Package substrate and forming method thereof, package structure and forming method thereof

Abstract

The present invention relates to a packaging substrate and a method for forming the same, and a packaging structure and a method for forming the same. The packaging substrate comprises: a substrate having a first surface and a second surface opposite to each other; at least one exhaust hole penetrating the first surface and the second surface of the substrate, wherein the exhaust hole comprises at least one long strip-shaped hole. The packaging substrate is conducive to improving the filling effect of the molding compound in the injection molding process and improving the reliability of the formed packaging structure.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a packaging substrate and a forming method thereof, and a packaging structure and a forming method thereof. Background Art

[0002] After the chip is packaged, it needs to be wrapped by injection molding to protect the chip.

[0003] For chips packaged by flip chip process, the chip and the substrate are connected to the circuit on the substrate through solder balls. In the plastic encapsulation process, the entire chip needs to be wrapped with plastic encapsulation material to fill the gap between the chip and the substrate. Since the chip and the substrate are directly connected through solder balls or other solder bumps, the gap is small and the distance between the connection points is also small. Therefore, it is difficult for the air to be discharged when the plastic encapsulation material is filled, which is prone to the problem of unreliable packaging structure.

[0004] In the prior art, in order to facilitate the discharge of gas during the injection molding process, air holes are set on the packaging substrate, so that during the injection molding process, as the plastic molding compound is filled, the gas is discharged from the air holes on the substrate, thereby improving the filling effect of the plastic molding compound fluid and reducing the phenomenon of unfilled air holes and punching. However, the existing chips are usually designed with non-square dimensions, and a single exhaust hole is easy to achieve the expected effect in the short side direction of the chip, but it is often difficult to achieve the expected effect in the long side direction of the chip, and there will still be many air holes, and the plastic molding compound filling effect is poor, affecting the reliability of the product.

[0005] How to further improve the filling effect of the plastic sealing compound during the injection molding process is a problem that needs to be solved urgently. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a packaging substrate and a forming method thereof, a packaging structure and a forming method thereof, so as to improve the filling effect of the plastic packaging material during the packaging injection molding process.

[0007] In order to solve the above problems, the present invention provides a packaging substrate, including: a substrate having a first surface and a second surface opposite to each other; at least one exhaust hole penetrating the first surface and the second surface of the substrate, and the exhaust hole includes at least a long strip hole.

[0008] Optionally, the exhaust hole includes more than two cross-connected long strip holes.

[0009] Optionally, more than two exhaust holes are included and are evenly distributed in the length direction of the packaging substrate.

[0010] Optionally, the exhaust hole is symmetrical about the symmetry axis of the packaging substrate.

[0011] Optionally, the cross-sectional edge of the exhaust hole parallel to the substrate surface is a smooth line.

[0012] Optionally, the elongated hole is formed by connecting a number of continuous circular holes.

[0013] Optionally, the inner wall of the exhaust hole has a passivated surface.

[0014] Optionally, the width-to-length ratio of the elongated holes is in the range of 1:1.3 to 1:15.

[0015] Optionally, it also includes: at least one circular hole distributed on the central axis of the substrate.

[0016] In order to solve the above problems, a specific embodiment of the present invention also provides a method for forming a packaging substrate, including: providing a substrate, the substrate having a first surface and a second surface; forming at least one exhaust hole, the exhaust hole passing through the first surface and the second surface of the substrate, and the exhaust hole includes at least one long strip-shaped hole.

[0017] Optionally, the exhaust hole includes more than two cross-connected long strip holes.

[0018] Optionally, more than two exhaust holes are included and are evenly distributed in the length direction of the packaging substrate.

[0019] Optionally, the exhaust hole is symmetrical about the symmetry axis of the packaging substrate.

[0020] Optionally, the cross-sectional edge of the exhaust hole parallel to the substrate surface is a smooth line.

[0021] Optionally, the method for forming the elongated hole includes: forming a plurality of continuous circular holes penetrating the substrate, and the plurality of continuous circular holes are interconnected to form the elongated hole.

[0022] Optionally, the method further includes: passivating the inner wall surface of the exhaust hole.

[0023] Optionally, the width-to-length ratio of the elongated holes is in the range of 1:1.3 to 1:15.

[0024] Optionally, it further includes: forming at least one circular hole, wherein the circular hole is distributed on the central axis of the substrate.

[0025] The technical solution of the present invention also provides a packaging structure, comprising: a packaging substrate as described in any one of the above items; a chip, the chip is flip-chip fixed on the first surface of the substrate through welding bumps, an electrical connection is formed between the chip and the substrate through the welding bumps, and the exhaust hole is located within the projection of the chip on the substrate; a plastic encapsulation material wraps the chip and fills the gap between the chip and the first surface of the substrate and the exhaust hole.

[0026] The technical solution of the present invention also provides a method for forming a packaging structure, comprising: providing a packaging substrate as described in any one of the above items; using a flip-chip process to flip-chip fix a chip on the first surface of the substrate through welding bumps, forming an electrical connection between the welding bumps and the substrate, and the exhaust holes in the substrate are located within the projection of the chip on the substrate; injection molding the chip flipped on the substrate, wrapping the chip with a plastic encapsulation material, and filling the gap between the chip and the first surface of the substrate and the exhaust holes.

[0027] The package substrate of the present invention has exhaust holes penetrating the substrate, and the exhaust holes include long strip holes, which can improve the exhaust effect and reduce the risk of the exhaust holes being blocked during the injection molding process. In addition, while improving the exhaust effect, the number of exhaust holes is reduced, so that the welding area between the substrate and the chip is more concentrated, avoiding waste of design area. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of pores on a substrate being blocked by impurities;

[0029] Figure 2a to Figure 2e It is a structural schematic diagram of a packaging substrate according to a specific embodiment of the present invention;

[0030] Figure 3 It is a structural schematic diagram of a packaging substrate according to a specific embodiment of the present invention;

[0031] Figure 4a It is a structural schematic diagram of a packaging substrate according to a specific embodiment of the present invention;

[0032] Figure 4b It is a structural schematic diagram of a packaging substrate according to a specific embodiment of the present invention;

[0033] Figure 5 It is a structural schematic diagram of a packaging substrate according to a specific embodiment of the present invention;

[0034] Figure 6 It is a structural schematic diagram of a packaging substrate according to a specific embodiment of the present invention;

[0035] Figure 7 It is a structural schematic diagram of a packaging substrate according to a specific embodiment of the present invention;

[0036] Figures 8a to 8c It is a structural schematic diagram of a packaging substrate according to a specific embodiment of the present invention;

[0037] Fig. 9 It is a schematic structural diagram of a packaging structure according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0038] As described in the background art, the pores formed on the substrate in the prior art are conducive to the discharge of gas in the short side direction of the chip during the injection molding process, thereby improving the filling effect of the plastic encapsulation material in the short side direction. However, there are still filling problems such as bubbles in the long side direction of the chip.

[0039] The inventors have found that in the long side direction of the chip, since the plastic encapsulation material needs to flow through more solder bump areas, it will produce a more obvious peristaltic flow (Re<<1 in fluid mechanics, or low Reynolds number flow), causing a turbulent influx of plastic encapsulation material containing more bubbles, so the exhaust effect through a single circular hole is poor; the above problem can be improved by arranging more air holes in the long side direction of the chip, but the increase in air holes will occupy the soldering area between the chip and the substrate, making the soldering area dispersed and wasting the design area.

[0040] The inventors further discovered that the existing air holes are all set in a circular shape. When the plastic packaging material contains solid or semi-solid impurities, it will be difficult for them to pass through, or the air holes will be blocked, resulting in greater filling abnormalities. Please refer to Figure 1 , the substrate 100 is provided with an air hole 101 at the center. When the impurities 102 in the plastic encapsulation material are larger than the diameter of the air hole 101 or are equal to the diameter of the air hole 101, no matter how the impurities 102 change their positions, it is difficult to be discharged or separated from the air hole 101, and they are easily stuck in the air hole 101, which makes it impossible to discharge the gas. Although the air hole diameter can be directly enlarged to improve the problems of bubbles and blockage, it will also excessively occupy the soldering bumps of the chip and the soldering area of ​​the substrate, and the plastic encapsulation material may directly fall and flow out from the large-diameter air hole, resulting in the situation that the plastic encapsulation material is not fully filled in the area around the air hole.

[0041] Based on the above research, the inventors have proposed a new packaging substrate and a method for forming the same, as well as a packaging structure based on the packaging substrate and a method for forming the same, to solve the above problems.

[0042] The specific implementation methods of the packaging substrate and the forming method thereof, the packaging structure and the forming method thereof provided by the present invention are described in detail below with reference to the accompanying drawings.

[0043] Please refer to Figures 2a to 2c, is a schematic diagram of the structure of a packaging substrate according to a specific embodiment of the present invention. Figure 2a is a schematic top view of the substrate 200, Figure 2b For along Figure 2a Schematic diagram of the cross section of the secant line AA'; Figure 2c For along Figure 2a Schematic cross-section of the secant line BB'.

[0044] The packaging substrate includes: a substrate 200 and an exhaust hole 210 penetrating the substrate 200 .

[0045] The substrate 200 has a first surface 201 and a second surface 202 opposite to each other. The substrate 200 may be a circuit board, and an interconnection circuit, a pad and other electrical connection structures are formed on the surface and / or inside of the substrate 200, which are used to form an electrical connection with the chip, input an electrical signal to the chip or output an electrical signal generated by the chip. The shape of the substrate 200 usually corresponds to the shape of the chip to be packaged, and is a square or a rectangle. In this specific embodiment, the substrate 200 is a rectangle, with the length direction along the Y direction and the width direction along the X direction.

[0046] The exhaust hole 210 is a long strip hole that passes through the first surface 201 and the second surface 202 of the substrate 200. The first surface 201 of the substrate 200 is a welding area outside the exhaust hole 210, and a metal connection layer is formed for welding with the chip to be packaged. In other specific embodiments, the exhaust hole 210 includes at least one long strip hole, and other hole structures connected to the long strip hole. In this specific embodiment, the exhaust hole 210 is in the shape of a long straight line. In other specific embodiments, the exhaust hole 210 can also be a broken line or a curve. Specifically, the shape of the exhaust hole can be set according to the distribution of the welding bumps. While improving the exhaust effect, it is possible to avoid making the welding area on the substrate 200 too dispersed, thereby reducing the waste of area.

[0047] When the exhaust hole 210 is in the shape of an elongated strip, the aperture area is larger and the exhaust effect is better; and, if the molding compound contains solid or semi-solid impurities, as the molding compound flows, the impurities are not easily stuck in the exhaust hole, thereby reducing the possibility of the exhaust hole 210 being blocked; and, even if the impurities are stuck in the exhaust hole 210, since the exhaust hole 210 is in the shape of an elongated strip, the gas can also be discharged from both sides of the impurities, thereby preventing the exhaust hole from being completely blocked.

[0048] In this specific embodiment, the length direction of the exhaust hole 210 is consistent with the length direction of the substrate 200. Since the distance that the plastic encapsulation material flows in the Y-axis direction of the substrate 200 during the injection molding process is relatively long and passes through more welding bumps, the exhaust hole 210 is relatively long in the Y-direction, which can improve the exhaust effect in the Y-direction. In addition, the exhaust hole 210 is arranged along the symmetry axis of the substrate 200 and is symmetrical about the alignment axis. Since the plastic encapsulation material usually flows from the edge to the center of the substrate 200 during the injection molding process, the exhaust hole 210 is arranged at the symmetry axis, which can improve the uniformity of exhaust.

[0049] The width-to-length ratio of the exhaust hole 210 is in the range of 1:1.3 to 1:15 to obtain a better exhaust effect. Preferably, the width-to-length ratio of the exhaust hole 210 is in the range of 1:2 to 1:7, which can achieve a better exhaust effect while avoiding occupying more substrate area.

[0050] In other specific implementations, two or more exhaust holes may be formed in the substrate 200 .

[0051] Please refer to Figure 3 , is a top view schematic diagram of a packaging substrate according to another specific embodiment of the present invention. In this specific embodiment, two exhaust holes 310 are formed in the substrate 300, and the exhaust holes 310 are long strip holes. The length direction of the exhaust holes 310 is consistent with the length direction of the substrate 300, and they are distributed along the symmetry axis.

[0052] Please refer to Figure 4a , is a schematic top view of a packaging substrate according to another specific embodiment of the present invention. In this specific embodiment, three exhaust holes 410 are formed in the substrate 400, and the length direction of the exhaust holes 410 can be consistent with the width direction of the substrate 400, and are evenly distributed in the width direction of the substrate 400.

[0053] Please refer to Figure 4b , is a top view schematic diagram of a packaging substrate according to another specific embodiment, wherein two exhaust holes 420 are arranged at an angle.

[0054] In other specific embodiments, the number and distribution of the exhaust holes 410 and the exhaust holes 420 on the substrate 200 can be reasonably set according to the distribution of the welding area on the substrate 200 and the simulation effect of the flow rate of the plastic packaging material fluid. The length-to-width ratio of the long strip holes of the exhaust holes 410 and 420 is 1:1.3 to 1:15, which has a good effect of exhausting and avoiding impurity clogging.

[0055] In other specific embodiments, at least one circular hole may be formed on the substrate, penetrating the first surface and the second surface of the substrate. The circular hole may be distributed on the central axis of the substrate, preferably, distributed on the central axis along the length direction of the substrate.

[0056] Please refer to Figure 5 , is a schematic top view of a packaging substrate according to another specific embodiment of the present invention.

[0057] In this specific embodiment, the exhaust holes 510 in the substrate 500 include two cross-connected long strip holes 510 and holes 520, which are in a cross shape. In this specific embodiment, the hole 501 and the hole 502 have the same size, and the length directions of the two holes are respectively consistent with the length and width directions of the substrate 500. And the hole 510 is located at the center of the substrate 500. In another specific embodiment, the size of the hole 501 and the hole 502 can also be different. Preferably, the length of the hole 501 extending along the long side of the substrate 500 is greater than the length of the hole 502 extending along the short side of the substrate 500.

[0058] In other specific embodiments, the exhaust hole may also include three or more cross-connected long strip holes, the cross angles may be perpendicular or inclined to each other, and the cross position may be in the middle or at the end, which is not limited here.

[0059] Please continue to refer to Figure 2a , the exhaust hole 210 has a smooth inner wall edge. Specifically, the cross-sectional edge of the exhaust hole 210 parallel to the surface of the substrate 200 is a smooth line, and is connected in an arc shape at the length and width corner position to avoid sharp protrusions inside the exhaust hole 210 causing turbulence when the gas or fluid passes through, affecting the filling effect of the plastic packaging material. The exhaust hole 210 can be formed by drilling, laser etching or etching. Furthermore, the inner wall surface of the exhaust hole 210 can also be passivated so that the inner wall surface of the exhaust hole 210 has a passivated surface to ensure that the exhaust hole 210 has a smooth inner wall edge. The passivated surface can be a passivation layer surface covering the side wall of the exhaust hole 210.

[0060] In this specific embodiment, the sidewall of the exhaust hole 210 is perpendicular to the surface of the substrate 200. In other specific embodiments, the exhaust hole 210 may also have an inclined sidewall (see Figure 2d The middle vent hole 210a), or the middle part is larger and the two ends are smaller (please refer to Figure 2e The middle exhaust hole 210b) is not limited here.

[0061] Please refer to Figure 6, is a schematic top view of a packaging substrate according to a specific embodiment of the present invention.

[0062] The exhaust hole 610 in the substrate 600 of the package substrate is formed by connecting a plurality of continuous circular holes 601. The size of each circular hole 601 is the same, and the size and shape of the exhaust hole 610 can be adjusted by controlling the number and arrangement of the circular holes 601, which is convenient for implementation.

[0063] In this specific implementation, the exhaust hole 610 is formed by a plurality of circular holes connected to each other, and there is a protruding sharp corner at the intersection of the edges of adjacent circular holes, so that the smoothness of the exhaust hole 610 needs to be improved.

[0064] Please refer to Figure 7 , is a schematic diagram of a packaging substrate according to another specific embodiment of the present invention.

[0065] exist Figure 6 Based on the packaging substrate shown, a passivation layer 710 is also formed on the inner wall surface of the exhaust hole 610. The passivation layer 710 makes the protruding sharp corners of the inner wall of the exhaust hole 610 smooth and the surface is arc-shaped, thereby reducing the risk of turbulence when gas or fluid passes through the exhaust hole 610.

[0066] The passivation layer 710 may be formed by a metallization process. In some specific embodiments, the passivation layer 710 may be a metal layer formed by a sputtering process, such as a Cu layer, a W layer, etc.

[0067] In other specific implementations, the passivation layer 710 may also be formed on the inner wall surface of the exhaust hole 610 by chemical deposition. The passivation layer 710 may also be made of other materials that are easy to cover the inner wall of the exhaust hole.

[0068] In other specific implementations, the inner wall of the exhaust hole 610 may be ground to remove protruding corners, so that the inner wall of the exhaust hole 610 is smooth without sharp protrusions.

[0069] The package substrate in the above specific embodiment has a long strip of vent holes, which can improve the venting effect and reduce the risk of the vent holes being blocked during the injection molding process. In addition, while improving the venting effect, the number of vent holes is reduced, so that the welding area between the substrate and the chip is more concentrated, avoiding waste of design area.

[0070] A specific embodiment of the present invention further provides a structural schematic diagram of the formation process of the above-mentioned packaging substrate.

[0071] by Figure 2a The package substrate is shown as an example.

[0072] First, a substrate 200 is provided, and the substrate 200 has a first surface 201 and a second surface 202 opposite to each other. The substrate 200 may be a circuit board, and an interconnection circuit, a pad and other electrical connection structures are formed on the surface and / or inside of the substrate 200, which are used to form an electrical connection with the chip, input an electrical signal to the chip or output an electrical signal generated by the chip. The shape of the substrate 200 usually corresponds to the shape of the chip to be packaged, and is a square or a rectangle.

[0073] Then, an exhaust hole 210 is formed in the substrate 200 . The exhaust hole 210 passes through the first surface 201 and the second surface 202 of the substrate 200 . The exhaust hole 210 is a long strip-shaped hole.

[0074] The first surface 201 of the substrate 200 is a welding area outside the exhaust hole 210, and a metal connection layer is formed thereon for welding with the chip to be packaged. In other specific embodiments, the exhaust hole 210 includes at least one long strip hole, and other hole structures connected to the long strip hole. In this specific embodiment, the exhaust hole 210 is in the shape of a long straight line, and in other specific embodiments, the exhaust hole 210 can also be a broken line or a curve. While improving the exhaust effect, it is possible to avoid making the welding area on the substrate 200 too dispersed, thereby reducing the waste of area.

[0075] In this specific embodiment, the length direction of the exhaust hole 210 is consistent with the length direction of the substrate 200. In other specific embodiments, the length direction of the exhaust hole 210 may also be consistent with the width direction of the substrate 200, or may be inclined.

[0076] In other specific embodiments, two or more exhaust holes may be formed in the substrate 200. The exhaust holes may include two or more cross-connected long strip holes.

[0077] The width-to-length ratio of the long strip-shaped holes is 1:1.3 to 1:15, preferably 1:2 to 1:7.

[0078] In other specific embodiments, at least one circular hole may be formed on the substrate, penetrating the first surface and the second surface of the substrate. The circular hole may be distributed on the central axis of the substrate, preferably, distributed on the central axis along the length direction of the substrate.

[0079] Those skilled in the art can reasonably set the number, position, shape and size of the exhaust holes as needed, which are not limited here.

[0080] Please refer to Figures 8a to 8c , is a schematic diagram of the formation process of the exhaust hole according to a specific embodiment of the present invention.

[0081] Please refer to Figure 8a , a circular hole 801 is formed on the substrate 800, Figure 8a The figure includes a top view schematic diagram after the circular hole 801 is formed by drilling, and a cross-sectional schematic diagram along the secant line CC' in the top view schematic diagram;

[0082] Please refer to Figure 8b , a circular hole 802 of the same size is formed by drilling at the edge of the circular hole 801 , and the circular hole 802 overlaps with the circular hole 801 , so that the circular hole 802 is connected with the circular hole 801 .

[0083] Please refer to Figure 8c , and continue to form a circular hole 803 and a circular hole 804 along the same straight line. The circular holes 801-804 are interconnected to form a long strip-shaped exhaust hole 810.

[0084] Subsequently, the inner wall surface of the exhaust hole 810 may be passivated, for example, by forming a passivation layer or performing a grinding layer treatment, so that the inner wall surface of the exhaust hole 810 is smoother and has no sharp protrusions.

[0085] The passivation treatment may be a metallization treatment. In a specific embodiment, the metallization treatment includes: forming a metal layer on the inner wall surface of the exhaust hole 810 and the surface of the substrate 800 by sputtering, electroplating or metal organic vapor deposition (MOCVD) process; then removing the metal layer on the surface of the substrate 800 by grinding or etching, leaving only the metal layer covering the inner wall of the exhaust hole 810 as a passivation layer. If the thickness of the metal layer covering the exhaust hole 810 is too large after grinding or etching, it can be re-drilled with a drill bit of a smaller aperture, leaving only a thinner metal layer as a passivation layer. The material of the metal layer may be a metal material commonly used in semiconductor processes such as W or Cu.

[0086] A specific embodiment of the present invention further provides a packaging structure using the above packaging substrate.

[0087] Please refer to Fig. 9 , which is a schematic structural diagram of a packaging structure according to a specific embodiment of the present invention.

[0088] In this specific implementation, Figure 2b The packaging substrate described in is taken as an example.

[0089] The packaging structure includes: a packaging substrate, the packaging substrate includes a substrate 200 and an exhaust hole 210 passing through the substrate 200; a chip 900, the chip 900 is flip-chip fixed on the first surface 201 of the substrate 200 through a welding bump 901, an electrical connection is formed between the welding bump 901 and the substrate 200, and the exhaust hole 210 is located within the projection of the chip 900 on the substrate 200; a plastic encapsulation material 910, wrapping the chip 900 and filling the gap between the chip 900 and the first surface 201 of the substrate 200 and the exhaust hole 210.

[0090] The exhaust hole 210 in the package is a long strip-shaped hole that passes through the first surface 201 and the second surface 202 of the substrate 200 .

[0091] The package structure further includes solder balls 920 formed on the second surface 202 of the substrate 200 .

[0092] In the above-mentioned packaging structure, since long strip-shaped exhaust holes are formed in the packaging substrate, the filling effect of the plastic encapsulation material 910 can be effectively improved in all directions, so that the plastic encapsulation material 910 can fully fill the gap between the chip 900 and the substrate 200, reduce the problem of poor filling such as air holes, and improve the reliability of the packaging structure.

[0093] The exhaust holes in the packaging substrate of the packaging structure may also adopt other structures. Please refer to the description in the aforementioned specific implementation manner for details, which will not be repeated here.

[0094] A specific embodiment of the present invention further provides a method for forming the above-mentioned packaging structure.

[0095] The method for forming the packaging structure comprises the following steps:

[0096] Step 1: providing a packaging substrate, wherein the packaging substrate has a first surface and a second surface opposite to each other; at least one exhaust hole passes through the first surface and the second surface of the substrate, wherein the exhaust hole comprises at least one long strip-shaped hole.

[0097] Step 2: Through a flip-chip process, the chip is flip-chip fixed on the first surface of the substrate through solder bumps, an electrical connection is formed between the solder bumps and the substrate, and the exhaust holes in the substrate are located within the projection of the chip on the substrate.

[0098] Step 3: performing injection molding on the chip flipped on the substrate, wrapping the chip with a molding compound, and filling the gap between the chip and the first surface of the substrate and the exhaust hole.

[0099] A substrate with a flip chip on its surface can be placed in a cavity of an injection mold, with the second surface of the substrate located on the bottom surface of the cavity; liquid molding compound is then injected into the cavity and cured, so that the molding compound fills the cavity, wraps the chip, and fills the gap between the chip and the substrate surface.

[0100] During the injection of the molding compound, the gas in the cavity is discharged through at least part of the exhaust holes. The bottom of the cavity may have a groove connected to the exhaust holes in the substrate, and the groove is connected to the outside of the packaging mold to discharge the gas out of the cavity.

[0101] Since the exhaust hole comprises a long strip hole, it is not easy to be blocked and has a large aperture, which improves the exhaust efficiency. Therefore, before the molding compound completely fills the cavity, it can continue to serve as a gas exhaust channel to improve the filling effect of the molding compound.

[0102] Step 4: forming solder balls on the second surface of the substrate.

[0103] After the injection molding process is completed, solder balls are formed on the second surface of the substrate, and the solder balls can be lead solder balls or lead-free solder balls, etc. Subsequently, the package structure can be mounted on other electronic components such as other circuit boards through the solder balls through a reflow process.

[0104] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A packaging substrate, characterized in that: include: A substrate having a first surface and a second surface opposite to each other, wherein the shape of the substrate corresponds to the shape of the chip to be packaged, and is a square or a rectangle; At least one exhaust hole, passing through the first surface and the second surface of the substrate, the exhaust hole at least comprising a long strip hole; The inner wall of the exhaust hole has a passivation surface.

2. The packaging substrate according to claim 1, characterized in that: The exhaust hole includes at least two or more cross-connected long strip holes.

3. The packaging substrate according to claim 1, characterized in that: It comprises more than two exhaust holes which are evenly distributed in the length direction of the packaging substrate.

4. The packaging substrate according to claim 1, characterized in that: The exhaust hole is symmetrical about a symmetry axis of the packaging substrate.

5. The packaging substrate according to claim 1, characterized in that: The cross-sectional edge of the exhaust hole parallel to the substrate surface is a smooth line.

6. The packaging substrate according to claim 1, characterized in that: The long strip-shaped hole is formed by connecting a number of continuous circular holes.

7. The packaging substrate according to claim 1, characterized in that: The width-to-length ratio of the long strip holes is in the range of 1:1.3 to 1:

15.

8. The packaging substrate according to claim 1, characterized in that: Also includes: At least one circular hole is distributed on the central axis of the substrate.

9. A method for forming a packaging substrate, characterized in that: include: Providing a substrate, wherein the substrate has a first surface and a second surface, and the shape of the substrate corresponds to the shape of the chip to be packaged, and is a square or a rectangle; forming at least one exhaust hole, the exhaust hole penetrating through the first surface and the second surface of the substrate, the exhaust hole comprising at least one long strip-shaped hole; The inner wall surface of the exhaust hole is passivated.

10. The method for forming a package substrate according to claim 9, wherein: The exhaust hole includes two or more cross-connected long strip holes.

11. The method for forming a package substrate according to claim 9, wherein: It comprises more than two exhaust holes which are evenly distributed in the length direction of the packaging substrate.

12. The method for forming a package substrate according to claim 9, wherein: The exhaust hole is symmetrical about a symmetry axis of the packaging substrate.

13. The method for forming a package substrate according to claim 9, wherein: The cross-sectional edge of the exhaust hole parallel to the substrate surface is a smooth line.

14. The method for forming a package substrate according to claim 9, wherein: The method for forming the long strip-shaped hole comprises: forming a plurality of continuous circular holes penetrating the substrate, and the plurality of continuous circular holes are interconnected to form the long strip-shaped hole.

15. The method for forming a package substrate according to claim 9, wherein: The width-to-length ratio of the long strip holes is in the range of 1:1.3 to 1:

15.

16. The method for forming a package substrate according to claim 9, wherein: Also includes: At least one circular hole is formed, and the circular hole is distributed on the central axis of the substrate.

17. A packaging structure, characterized in that: include: The packaging substrate according to any one of claims 1 to 8; A chip, wherein the chip is flip-chip fixed on the first surface of the substrate through solder bumps, and an electrical connection is formed between the chip and the substrate through the solder bumps, and the exhaust hole is located within the projection of the chip on the substrate; The molding compound wraps the chip and fills the gap between the chip and the first surface of the substrate and the exhaust hole.

18. A method for forming a packaging structure, characterized in that: include: Providing a packaging substrate according to any one of claims 1 to 8; The chip is flip-chip fixed on the first surface of the substrate through welding bumps by a flip-chip process, the welding bumps are electrically connected to the substrate, and the exhaust holes in the substrate are located within the projection of the chip on the substrate; The chip flipped on the substrate is injection molded to wrap the chip with a molding compound and fill the gap between the chip and the first surface of the substrate and the exhaust hole.

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