Long-strip-shaped molding compound through hole structure and manufacturing method thereof

Abstract

According to the long-strip-shaped plastic packaging material through hole structure provided by the invention, by changing the geometrical shapes of the through holes, electrical connection is provided in the vertical direction, and meanwhile, through the staggered plastic packaging material through holes, a directional stress management capability is provided for a packaging structure, and remarkable mechanical support is provided for a packaging body in the plane direction; the rigidity of the packaging structure is greatly enhanced, and packaging warping caused by mismatching of thermal expansion coefficients is inhibited. The plastic package structure comprises a plastic package material, a long-strip-shaped through hole penetrating in the thickness direction is formed in the surface area of the plastic package material, the length of the long-strip-shaped through hole is larger than the width of the long-strip-shaped through hole, and the length direction of the long-strip-shaped through hole is a long axis.

Description

Technical Field

[0001] This invention relates to the technical field of semiconductor chip packaging, specifically to a long strip-shaped through-hole structure for molding compound. The invention also provides a method for manufacturing the long strip-shaped through-hole structure for molding compound. Background Technology

[0002] In advanced packaging, to protect the chip and achieve standard package dimensions, epoxy molding compound is typically used to encapsulate the chip and the bottom interconnect structure (interface board or redistribution layer). After molding, vias may need to be fabricated on the package to achieve electrical connections. Existing technologies typically create circular vias on the molding compound. However, due to the significant differences in the coefficients of thermal expansion of materials such as molding compound, silicon chip, metal, and dielectric materials, significant thermal stress is generated during subsequent reflow soldering and other thermal processes, causing the package to warp. The cylindrical vias in existing technologies have consistent mechanical properties in all directions, and multiple circular vias are distributed in a point-like manner, which cannot effectively suppress the large warping deformation of the package caused by thermal stress, seriously affecting the package yield and reliability. In addition, the cross-sectional area of ​​a single circular via is limited, and a large number of vias need to be connected in parallel to reduce resistance, occupying valuable wiring space and hindering further improvements in interconnect density and transmission efficiency. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a long strip-shaped molding compound through-hole structure. By changing the geometry of the through-holes, it provides electrical connection in the vertical direction while providing directional stress management capability for the packaging structure through the staggered arrangement of molding compound through-holes. It also provides significant mechanical support for the package in the planar direction, greatly enhancing the rigidity of the packaging structure and suppressing package warping caused by mismatch in thermal expansion coefficients.

[0004] A long strip-shaped through-hole structure for molding compound, characterized in that: it includes molding compound, and a long strip-shaped through-hole extending through the thickness direction is provided on the surface area of ​​the molding compound, the length of the long strip-shaped through-hole is greater than its width, and the length direction of the long strip-shaped through-hole is the major axis.

[0005] Its further features are: The cross-sectional shape of the elongated through hole is specifically a chamfered rectangle with chamfered corners or an elongated ellipse; Corresponding to the four corners of the package that are prone to warping, several elongated through holes are arranged at the four corners of the molding compound, with the inner end of the long axis of each group of elongated through holes pointing towards the center of the package. Corresponding to the four sides of the encapsulated body where warping is likely to occur, when bowl-shaped warping is likely to occur, the long axis of the elongated through holes on the corresponding side is arranged parallel to the corresponding side; when unidirectional warping is likely to occur, the long axis of all elongated through holes in the side area is arranged parallel to the long side. While ensuring electrical continuity, elongated through holes should be arranged in a staggered manner along their length to avoid discontinuities in the support structure in the direction of maximum warping.

[0006] A method for fabricating a long strip-shaped through-hole structure in a molding compound includes a chip, a bottom interconnect structure, a bottom filler, and a molding compound. The method is characterized by: fabricating long strip-shaped through-holes arranged at corresponding positions prone to warping on the molding compound located around the chip, and forming a metal connection structure within the long strip-shaped through-holes.

[0007] Its further features are: There are three methods for forming elongated through-holes with molding compound: molding first and then electroplating, electroplating first and then molding, and replacing the molding compound with a dielectric material such as dry film or organic polymer material before drilling and electroplating. The manufacturing process of molding followed by electroplating is as follows: After molding, a long through hole is made by laser drilling and the hole is cleaned; then an insulating layer is grown in the long through hole and a barrier layer and a seed layer are deposited, and the through hole is filled with electroplated copper; then chemical mechanical polishing is performed to remove excess insulating and metal layers and flatten the surface of the molding compound. The manufacturing process of electroplating followed by molding is as follows: a graphic pattern is created using photolithography to determine the location of the through-holes in the molding compound, and then an electroplating process is used to create the electroplated copper pillars; finally, the photoresist is removed, and the entire assembly, including the copper pillars, is molded; finally, the surface of the metal copper pillars is ground to expose them. The manufacturing process of drilling and electroplating after replacing plastic encapsulation with dielectric materials such as dry film or organic polymer materials is as follows: The outer periphery of the chip is covered with a sufficiently thick dielectric material by means of lamination or coating technology, thereby replacing the plastic encapsulation material. Then, laser drilling is used to create elongated through holes with graphic patterns on the dielectric material. Finally, electroplating process is used to create electroplated copper pillars.

[0008] By adopting the above technical solution, by changing the circular through-holes to elongated through-holes, electrical connections are provided in the vertical direction, while several rows of staggered elongated through-holes provide directional stress management capabilities for the package structure and significant mechanical support for the package in the planar direction. This greatly enhances the rigidity of the package structure, suppresses package warpage caused by mismatch in thermal expansion coefficients, and the copper pillars embedded in the elongated through-holes, with their larger cross-sectional area, provide lower resistance and inductance, making them particularly suitable for power and ground networks and improving electrical performance. Furthermore, the design of the elongated through-holes optimizes the layout, which is conducive to achieving higher interconnect density. Attached Figure Description

[0009] Figure 1 This is a schematic diagram showing the arrangement of the elongated through holes in the encapsulation body, which is prone to warping at the four corners and bowl-shaped warping at the four sides, in accordance with the present invention. Figure 2 This is a schematic diagram showing the arrangement of the elongated through holes in the encapsulation body, which is prone to warping at the four corners and unidirectional warping at the four sides, as described in this invention. Figure 3 A cross-sectional view of the package obtained by the method of the present invention; Figure 4 This is a cross-sectional view of the pre-molding and post-electroplating method in a specific embodiment of the present invention after the hole is opened following the molding process; Figure 5 This is a top view of the encapsulation-then-electroplating method in a specific embodiment of the present invention, after the hole is opened following encapsulation. Figure 1 ; Figure 6 This is a top view of the encapsulation-then-electroplating method in a specific embodiment of the present invention, after the hole is opened following encapsulation. Figure 2 ; Figure 7 This is a top view of the pre-molding and post-electroplating method in a specific embodiment of the present invention after electroplating. Figure 1 ; Figure 8 This is a top view of the pre-molding and post-electroplating method in a specific embodiment of the present invention after electroplating. Figure 2 ; The names corresponding to the serial numbers in the diagram are as follows: 1. Long through hole; 101. Chamfered rectangle; 102. Long oval; 2. Electroplated copper. Molding compound 10, chip 20, bottom interconnect structure 30, underfill 40. Detailed Implementation

[0010] A long strip-shaped through-hole structure for molding compound, see Figures 1-3 It includes molding compound 10, and the surface area of ​​molding compound 10 is provided with an elongated through hole 1 extending through the thickness direction. The length of the elongated through hole 1 is greater than its width, and the length direction of the elongated through hole 1 is the major axis.

[0011] In specific implementation, the cross-sectional shape of the elongated through hole 1 is a chamfered rectangle 101 with chamfered corners or an elongated ellipse 102. Corresponding to the four corners of the package 10 where warping is likely to occur, see... Figure 1 and Figure 2 Several elongated through holes 1 are arranged at the four corners of the molding compound 10, and the inner end of the long axis of each group of elongated through holes 1 points to the center of the package body. Corresponding to the four sides of the molded body 10 where warping is likely to occur, when bowl-shaped warping is likely to occur, see... Figure 1 The long axis of the elongated through-hole 1 located on the corresponding side is arranged parallel to the corresponding side. When unidirectional warping is prone to occur, see... Figure 2 All the elongated through holes 1 located in the edge area are arranged with their long axes parallel to the long side.

[0012] While ensuring electrical continuity, the elongated through-hole 1 should be arranged in a staggered manner in the length direction of adjacent rows of elongated through-holes 1 to avoid discontinuity of the support structure in the direction of maximum warping.

[0013] A method for fabricating a long strip-shaped through-hole structure in a molding compound includes a chip 20, a bottom interconnect structure 30, a bottom filler 40, and a molding compound 10. Long strip-shaped through-holes 1 are fabricated on the molding compound 10 located around the chip 20 at corresponding positions prone to warping, and a metal connection structure is formed within the long strip-shaped through-holes 1.

[0014] In practice, there are three methods for forming elongated through-holes with molding compound: molding first and then electroplating, electroplating first and then molding, and replacing the molding compound with a dielectric material such as dry film or organic polymer material before drilling and electroplating.

[0015] The manufacturing process of encapsulation followed by electroplating is as follows: After encapsulation with encapsulating material 10, elongated through-holes 1 are created using laser drilling, and the inside of the holes is cleaned; then, an insulating layer is grown inside the elongated through-hole 1, and a barrier layer and a seed layer are deposited; the through-hole is then filled with electroplated copper 2; finally, chemical mechanical polishing is performed to remove excess insulating and metal layers, making the surface of the encapsulating material planar. See the specific embodiment below. Figures 4-8 The four corners of the package 10 are prone to warping, and the four sides are prone to bowl-shaped warping. The layout of the elongated through-hole 1 is shown in the figure. Figures 5-8 The elongated through hole 1 has two designs: a chamfered rectangle 101 or an elongated oval 102.

[0016] The manufacturing process of electroplating followed by molding is as follows: a graphic pattern is created using photolithography to determine the location of the through-holes in the molding compound, and then an electroplating process is used to create the electroplated copper pillars; finally, the photoresist is removed, and the entire assembly, including the copper pillars, is molded; finally, the surface of the metal copper pillars is exposed by grinding.

[0017] The manufacturing process of drilling and electroplating after replacing plastic encapsulation with dielectric materials such as dry film or organic polymer materials is as follows: The outer periphery of the chip is covered with a sufficiently thick dielectric material by means of lamination or coating technology, thereby replacing the plastic encapsulation material. Then, laser drilling is used to create elongated through holes with graphic patterns on the dielectric material. Finally, electroplating process is used to create electroplated copper pillars.

[0018] By replacing circular vias with elongated vias, this design provides electrical connectivity in the vertical direction while offering directional stress management capabilities through several rows of staggered elongated vias. It also provides significant mechanical support for the package in the planar direction, greatly enhancing the rigidity of the package structure and suppressing package warpage caused by thermal expansion mismatch. The elongated vias contain embedded copper pillars, whose larger cross-sectional area provides lower resistance and inductance, making them particularly suitable for power and ground networks and improving electrical performance. Furthermore, the elongated via design optimizes the layout, facilitating higher interconnect density.

[0019] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0020] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A long strip-shaped through-hole structure for molding compound, characterized in that: It includes a molding compound, on the surface of which is provided an elongated through-hole extending through the thickness direction, the length of which is greater than its width, and the length direction of which is the major axis.

2. The elongated through-hole structure of molding compound according to claim 1, characterized in that: The cross-sectional shape of the elongated through hole is specifically a chamfered rectangle with chamfered corners or an elongated ellipse.

3. The elongated through-hole structure of molding compound according to claim 2, characterized in that: Corresponding to the four corners of the package that are prone to warping, several elongated through holes are arranged at the four corners of the molding compound, with the inner end of the long axis of each group of elongated through holes pointing towards the center of the package.

4. The elongated through-hole structure of molding compound according to claim 2, characterized in that: Corresponding to the four sides of the encapsulated body where warping is likely to occur, when bowl-shaped warping is likely to occur, the long axis of the elongated through holes located on the corresponding side is arranged parallel to the corresponding side. When unidirectional warping is likely to occur, the long axis of all elongated through holes located in the side area is arranged parallel to the long side.

5. The elongated through-hole structure of molding compound according to claim 2, characterized in that: While ensuring electrical continuity, elongated through holes should be arranged in a staggered manner along their length to avoid discontinuities in the support structure in the direction of maximum warping.

6. A method for fabricating an elongated through-hole structure for molding compound, comprising a chip, a bottom interconnect structure, a bottom filler, and molding compound, wherein the method employs an elongated through-hole structure for molding compound as described in any one of claims 1-5, characterized in that: Long, narrow through-holes are fabricated on the molding compound surrounding the chip, according to the corresponding positions where warping is likely to occur, and a metal connection structure is formed within the long, narrow through-holes.

7. The method for manufacturing a long strip-shaped through-hole structure for molding compound according to claim 6, characterized in that: There are three methods for forming elongated through-holes with molding compound: molding first and then electroplating, electroplating first and then molding, and replacing the molding compound with a dielectric material such as dry film or organic polymer material before drilling and electroplating.

8. The method for manufacturing a long strip-shaped through-hole structure for molding compound according to claim 7, characterized in that, The manufacturing process of molding followed by electroplating is as follows: After molding, a long through hole is made by laser drilling and the hole is cleaned; then an insulating layer is grown in the long through hole and a barrier layer and a seed layer are deposited, and the through hole is filled with electroplated copper; then chemical mechanical polishing is performed to remove excess insulating and metal layers and flatten the surface of the molding compound.

9. A method for manufacturing a long strip-shaped through-hole structure for molding compound according to claim 7, characterized in that, The manufacturing process of electroplating followed by molding is as follows: a graphic pattern is created using photolithography to determine the location of the through-holes in the molding compound, and then an electroplating process is used to create the electroplated copper pillars; finally, the photoresist is removed, and the entire assembly, including the copper pillars, is molded; finally, the surface of the metal copper pillars is exposed by grinding.

10. A method for manufacturing a long strip-shaped through-hole structure for molding compound according to claim 7, characterized in that, The manufacturing process of drilling and electroplating after replacing plastic encapsulation with dielectric materials such as dry film or organic polymer materials is as follows: The outer periphery of the chip is covered with a sufficiently thick dielectric material by means of lamination or coating technology, thereby replacing the plastic encapsulation material. Then, laser drilling is used to create elongated through holes with graphic patterns on the dielectric material. Finally, electroplating process is used to create electroplated copper pillars.

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