Multi-layer stacked packaging structure based on window type ball grid array and method thereof

Abstract

The invention relates to the technical field of semiconductors, in particular to a multi-layer stacked packaging structure based on a window type ball grid array and a method of the multi-layer stacked packaging structure. The front surface of the first chip is provided with a wire bonding pad, the first bonding wire is connected to the joint bonding pad on the lower surface of the substrate from the wire bonding pad on the first chip, the front surface of the first chip is provided with a lower-layer colloid, and the lower-layer colloid covers the joint bonding pad connected with the first chip, the first bonding wire and the wire bonding pad of the first chip, and the back surface of the first chip is bonded with the back surface of the second chip; according to the number of nth chips needing to be stacked, the front faces of the nth chips face upwards, and the nth chips are bonded to the upper surface of an upper layer of upper colloid through a die bonding adhesive film material; a bonding wire is connected to the bonding pad on the upper surface of the substrate from the routing pad on the nth chip; and the nth chip, the bonding wires and the upper layer of upper colloid are covered with epoxy plastic packaging materials in a glue injection mode to form a new layer of upper colloid. Compared with the prior art, through multiple times of glue injection and adjustment of the glue injection height, the problem that a wire arc is extruded and deformed is solved, and therefore stacking of multiple layers of chips is achieved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, in particular to a multi-layer stacking packaging structure based on a window ball grid array (Window BGA) and a method thereof. Background Art

[0002] The common window ball grid array multi-layer stacking packaging structure is often used for stacking 2 layers of chips. The reason is that the chip wire pads of the window ball grid array are distributed at the center line of the chip. Due to structural limitations, the chip bonding wires in the upper colloid are long and the bonding wire height is very high, making it difficult to stack other chips on top. It is necessary to solve the problem that the bonding wires of the second layer and above are squeezed and deformed by the colloid and cannot realize multi-layer chip stacking. Summary of the invention

[0003] In order to solve the problems raised in the above background technology, the purpose of the present invention is to provide a multi-layer stacked packaging structure based on a window ball grid array (Window BGA), comprising a substrate, a plurality of chips, and a multi-layer upper colloid, wherein the upper surface of the substrate is provided with a plurality of bonding pads, and the lower surface is provided with a plurality of solder balls and bonding pads; The front side of the first chip is provided with a wire bonding pad, the front side of the first chip is bonded to the substrate by epoxy resin glue, the first bonding wire is connected from the wire bonding pad on the first chip to the bonding pad on the lower surface of the substrate, the front side of the first chip is provided with a lower layer of colloid, the lower layer of colloid covers the bonding pad connected to the first chip, the first bonding wire and the wire bonding pad of the first chip, and the back side of the first chip is bonded to the back side of the second chip by a die attach film (DAF) material; The front side of the second chip is provided with two rows of wire bonding pads, the second bonding wires are connected from the wire bonding pads on the second chip to the bonding pads on the upper surface of the substrate, the front side of the second chip is provided with a first layer of upper colloid, the first layer of upper colloid covers the bonding pads connected to the second chip, the second bonding wires, and the wire bonding pads of the second chip, and the upper surface of the first layer of upper colloid is bonded to the back side of the third chip through a die attach film (DAF) material; The front side of the third chip is provided with two rows of wire bonding pads, the third bonding wires are connected from the wire bonding pads on the third chip to the bonding pads on the upper surface of the substrate, the front side of the third chip is provided with a second layer of upper colloid, the second layer of upper colloid covers the bonding pads connected to the third chip, the third bonding wires, and the wire bonding pads of the third chip, and the upper surface of the second layer of upper colloid is bonded to the back side of the fourth chip through a die attach film (DAF) material; The fourth chip is provided with two rows of wire bonding pads on the front side, and the fourth bonding wires are connected from the wire bonding pads on the fourth chip to the bonding pads on the upper surface of the substrate. The fourth chip is provided with a third layer of upper colloid on the front side, and the third layer of upper colloid covers the bonding pads, the fourth bonding wires, and the wire bonding pads of the fourth chip connected to the fourth chip.

[0004] The method includes the following steps: S1, facing the first chip face down, and bonding it to the upper surface of the substrate by epoxy resin glue; S2, connecting the wire bonding pad on the first chip to the bonding pad on the lower surface of the substrate by a first welding wire along the groove channel of the substrate; S3, facing the second chip face up, and bonding it to the back of the first chip by a die bonding film (DAF) material; S4, connecting the wire bonding pad on the second chip to the bonding pad on the upper surface of the substrate by a second welding wire; S5, using epoxy mold compound material to cover the first chip, the second chip, the first welding wire, and the second welding wire to form a first layer of upper colloid and a lower layer of colloid; S6, facing the third chip face up, and bonding it to the upper surface of the first layer of upper colloid by a die bonding film (DAF) material; S7, connecting the wire bonding pad on the third chip to the bonding pad on the upper surface of the substrate by a third welding wire; S8, using epoxy mold compound material to seal the first chip, the second chip, the first welding wire, and the second welding wire to form a first layer of upper colloid and a lower layer of colloid. Inject glue to cover the third chip, the third bonding wire and the first upper layer of the colloid to form a second upper layer of the colloid; S9, place the fourth chip with the front side facing up and adhere it to the upper surface of the second upper layer of the colloid through a die attach film (DAF) material; S10, use a fourth bonding wire to connect the wire bonding pad on the fourth chip to the bonding pad on the upper surface of the substrate; S11, inject glue to cover the fourth chip, the fourth bonding wire and the second upper layer of the colloid to form a third upper layer of the colloid.

[0005] The number of the multiple chips is greater than or equal to 3.

[0006] The first upper colloid, the second upper colloid and the third upper colloid are provided with heat dissipation blocks.

[0007] The method repeats step S12 according to the number of n-th chips to be stacked (n≥3), and places the n-th chip with the front side facing upward, and adheres it to the upper surface of the upper layer of the upper body through a die attach film (DAF) material; S13, uses a bonding wire to connect the wire bonding pad on the n-th chip to the bonding pad on the upper surface of the substrate; and S14, uses an epoxy mold compound material to inject glue to cover the n-th chip, the bonding wire and the upper layer of the upper body to form a new layer of the upper body.

[0008] Compared with the prior art, the present invention performs multiple glue injections and adjusts the glue injection height to solve the problem of wire arc deformation due to extrusion, thereby realizing multi-layer chip stacking, adding heat dissipation blocks, and enhancing the heat dissipation performance of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic cross-sectional structural diagram of this embodiment; Figure 2 This is a top view of the substrate during glue injection in this embodiment; Figure 3This is a cross-sectional view of part of the substrate during glue injection in this embodiment; See also Figure 1 , 1. First chip; 2. Second chip; 3. Third chip; 4. Fourth chip; 5. Lower layer colloid; 6. First layer upper colloid; 7. Second layer upper colloid; 8. Third layer upper colloid; 9. Epoxy resin glue; 10. Die attaching film (DAF) material; 11. First welding wire; 12. Bonding pad; 13. Solder ball; 14. Wire bonding pad; 15. Second welding wire; 16. Third welding wire; 17. Fourth welding wire; 18. Substrate. DETAILED DESCRIPTION

[0010] The present invention will be further described below with reference to the accompanying drawings.

[0011] like Figure 1 , a multi-layer stacked packaging structure based on a window ball grid array (Window BGA), a substrate 18 has a plurality of bonding pads 12 on its upper surface, and a plurality of solder balls 13 and bonding pads 12 on its lower surface; A bonding pad is provided on the front side of the first chip 1, and the front side of the first chip 1 is bonded to the substrate 18 by epoxy resin glue, and a first bonding wire 11 is connected from the bonding pad on the first chip 1 to a bonding pad 12 on the lower surface of the substrate 18, and a lower layer of colloid 5 is provided on the front side of the first chip 1, and the lower layer of colloid 5 covers the bonding pad 12 connected to the first chip 1, the first bonding wire 11 and the bonding pad 14 of the first chip 1, and the back side of the first chip 1 is bonded to the back side of the second chip 2 by a die attach film (DAF) material; The front side of the second chip 2 is provided with two rows of wire bonding pads 14, and the second bonding wires 15 are connected from the wire bonding pads 14 on the second chip 2 to the bonding pads 12 on the upper surface of the substrate 18. The front side of the second chip 2 is provided with a first layer of upper colloid 6, and the first layer of upper colloid 6 covers the bonding pads 12 connected to the second chip 2, the second bonding wires 15, and the wire bonding pads 14 of the second chip 2. The upper surface of the first layer of upper colloid 6 is bonded to the back side of the third chip 3 through a die attach film (DAF) material. The front side of the third chip 3 is provided with two rows of wire bonding pads 14, the third bonding wires 16 are connected from the wire bonding pads 14 on the third chip 3 to the bonding pads 12 on the upper surface of the substrate 18, the front side of the third chip 3 is provided with a second layer of upper colloid 7, the second layer of upper colloid 7 covers the bonding pads 12 connected to the third chip 3, the third bonding wires 16, and the wire bonding pads 14 of the third chip 3, and the upper surface of the second layer of upper colloid 7 is bonded to the back side of the fourth chip 4 through a die attach film (DAF) material; Two rows of bonding pads 14 are provided on the front side of the fourth chip 4, and fourth bonding wires 17 are connected from the bonding pads 14 on the fourth chip 4 to the bonding pads 12 on the upper surface of the substrate 18. A third layer of upper glue 8 is provided on the front side of the fourth chip 4, and the third layer of upper glue 8 covers the bonding pads 12 connected to the fourth chip 4, the fourth bonding wires 17, and the bonding pads 14 of the fourth chip 4.

[0012] The method includes the following steps: S1, facing down the first chip 1, and bonding it to the upper surface of the substrate 18 by epoxy resin glue; S2, connecting the wire bonding pad 14 on the first chip 1 to the bonding pad 12 on the lower surface of the substrate 18 by using a first bonding wire 11 along the groove channel of the substrate 18; S3, facing up the second chip 2, and bonding it to the back of the first chip 1 by using a die bonding film (DAF) material; S4, connecting the wire bonding pad 14 on the second chip 2 to the bonding pad 12 on the upper surface of the substrate 18 by using a second bonding wire 15; S5, using an epoxy mold compound to seal the second chip 2 with the bonding pad 14 on the second chip 2. The material is injected to cover the first chip 1, the second chip 2, the first bonding wire 11, and the second bonding wire 15 to form a first layer of upper colloid 6 and a lower layer of colloid 5; S6, the third chip 3 is facing up and bonded to the upper surface of the first layer of upper colloid 6 through a die bonding film (DAF) material; S7, the third bonding wire 16 is used to connect the wire bonding pad 14 on the third chip 3 to the bonding pad 12 on the upper surface of the substrate 18; S8, the third chip 3, the third bonding wire 16 and the first layer of upper colloid 6 are injected with epoxy mold compound material to form a second layer of upper colloid 7; S9, the fourth chip 4 is facing up and bonded to the upper surface of the second layer of upper colloid 7 through a die bonding film (DAF) material; S10, the fourth bonding wire 17 is used to connect the wire bonding pad 14 on the fourth chip 4 to the bonding pad 12 on the upper surface of the substrate 18; S11, the epoxy mold compound is used to The material is injected to cover the fourth chip 4 , the fourth bonding wire 17 and the second upper glue layer 7 to form a third upper glue layer 8 .

[0013] The number of multiple chips is greater than or equal to 3.

[0014] Heat dissipation blocks are arranged inside the first upper colloid, the second upper colloid and the third upper colloid.

[0015] The method repeats step S12 according to the number of n-th chips to be stacked (n≥3), places the n-th chip with its front side facing upward and adheres it to the upper surface of the previous upper layer of colloid through a die attach film (DAF) material; S13, connects the wire bonding pad 14 on the n-th chip to the bonding pad 12 on the upper surface of the substrate 18 through a bonding wire; S14, covers the n-th chip, the bonding wire and the previous upper layer of colloid with an epoxy mold compound material to form a new upper layer of colloid.

[0016] like Figures 2 to 3 In this embodiment, multiple injections are required to divide the substrate 18 into multiple units. Each injection is performed once for each unit. The colloid between units is separated. The latter injection is based on the former injection and covers the former injection in each unit. By injecting glue multiple times and adjusting the injection height, the problem of extrusion and deformation of the bonding wire is solved, thereby realizing multiple injections of multi-layer chip stacking products. The thickness of the colloid may be relatively thick. Heat dissipation blocks are added to the colloid to enhance the heat dissipation performance of the product.

Claims

1. A multi-layer stacked packaging structure based on a window-type ball grid array, comprising a substrate, a plurality of chips, and a multi-layer colloid, characterized in that: The upper surface of the substrate is provided with a plurality of bonding pads, and the lower surface is provided with a plurality of solder balls and bonding pads; The front side of the first chip is provided with a wire bonding pad, the front side of the first chip is bonded to the substrate by epoxy resin glue, the first bonding wire is connected from the wire bonding pad on the first chip to the bonding pad on the lower surface of the substrate, the front side of the first chip is provided with a lower layer of colloid, the lower layer of colloid covers the bonding pad connected to the first chip, the first bonding wire and the wire bonding pad of the first chip, and the back side of the first chip is bonded to the back side of the second chip by a die attach film (DAF) material; The front side of the second chip is provided with two rows of wire bonding pads, the second bonding wires are connected from the wire bonding pads on the second chip to the bonding pads on the upper surface of the substrate, the front side of the second chip is provided with a first layer of upper colloid, the first layer of upper colloid covers the bonding pads connected to the second chip, the second bonding wires, and the wire bonding pads of the second chip, and the upper surface of the first layer of upper colloid is bonded to the back side of the third chip through a die attach film (DAF) material; The front side of the third chip is provided with two rows of wire bonding pads, the third bonding wires are connected from the wire bonding pads on the third chip to the bonding pads on the upper surface of the substrate, the front side of the third chip is provided with a second layer of upper colloid, the second layer of upper colloid covers the bonding pads connected to the third chip, the third bonding wires, and the wire bonding pads of the third chip, and the upper surface of the second layer of upper colloid is bonded to the back side of the fourth chip through a die attach film (DAF) material; The fourth chip is provided with two rows of wire bonding pads on the front side, and the fourth bonding wires are connected from the wire bonding pads on the fourth chip to the bonding pads on the upper surface of the substrate. The fourth chip is provided with a third layer of upper colloid on the front side, and the third layer of upper colloid covers the bonding pads, the fourth bonding wires, and the wire bonding pads of the fourth chip connected to the fourth chip.

2. And the method comprises the following steps: S1, placing the first chip with the front side facing downward and bonding it to the upper surface of the substrate by epoxy resin glue; S2, connecting the first bonding wire from the wire bonding pad on the first chip to the bonding pad on the lower surface of the substrate along the grooved channel of the substrate; S3, placing the second chip with the front side facing upward and bonding it to the back side of the first chip through a die attach film (DAF) material; S4, connect the wire bonding pad on the second chip to the bonding pad on the upper surface of the substrate with a second bonding wire; S5, use epoxy mold compound material to inject glue to cover the first chip, the second chip, the first bonding wire, and the second bonding wire to form a first layer of upper glue and a lower layer of glue; S6, place the third chip with the front side facing up and adhere it to the upper surface of the first layer of upper glue through a die bonding film (DAF) material; S7, connect the wire bonding pad on the third chip to the bonding pad on the upper surface of the substrate with a third bonding wire; S8, use epoxy mold compound material to inject glue to cover the third chip, the third bonding wire, and the first layer of upper glue to form a second layer of upper glue; S9, place the fourth chip with the front side facing up and adhere it to the upper surface of the second layer of upper glue through a die bonding film (DAF) material; S10, connect the wire bonding pad on the fourth chip to the bonding pad on the upper surface of the substrate with a fourth bonding wire; S11, use epoxy mold compound The material is injected to cover the fourth chip, the fourth bonding wire and the second upper layer of glue to form a third upper layer of glue.

3. The multi-layer stacked package structure based on a window-type ball grid array according to claim 1, characterized in that: The number of the multiple chips is greater than or equal to 3.

4. The multi-layer stacked package structure based on a window-type ball grid array according to claim 1, characterized in that: The first upper colloid, the second upper colloid and the third upper colloid are provided with heat dissipation blocks.

5. The multi-layer stacked package structure based on a window-type ball grid array according to claim 1, characterized in that: The method repeats step S12 according to the number of n-th chips to be stacked (n≥3), and places the n-th chip with the front side facing upward, and adheres it to the upper surface of the upper layer of the upper body through a die attach film (DAF) material; S13, uses a bonding wire to connect the wire bonding pad on the n-th chip to the bonding pad on the upper surface of the substrate; and S14, uses an epoxy mold compound material to inject glue to cover the n-th chip, the bonding wire and the upper layer of the upper body to form a new layer of the upper body.

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