Step-type stacked chip packaging structure based on resin spacer and preparation process

Abstract

A step-type stacked chip packaging structure based on a resin spacer that includes: a plastic packaging material, a circuit board, a resin spacer, a first chip, a second chip and an electrical connection assembly. The resin spacer, the first chip, and the second chip are stacked on the circuit board respectively. The second chip is stacked on the first chip in a stepped manner. The circuit board, the first chip and the second chip are electrically connected together through the electrical connection assembly. The resin spacer uses a fiber glass fabric as its base material, a weight percent of the fiber glass fabric is 10-60 wt %, and the following components are attached to the fiber glass fabric as a percentage by the total weight of the resin spacer: 8-40 wt % of epoxy resin, 10-30 wt % of quartz powder, 2-10 wt % of aluminum oxide, 1-8 wt % of calcium oxide, and 1-8 wt % of curing agent.

Claims

1. A step-type stacked chip packaging structure based on a resin spacer comprising: a plastic packaging material, a circuit board, a resign spacer, a first chip, a second chip, and an electrical connection assembly, wherein the resin spacer, the first chip and the second chip are stacked on the circuit board in sequence, wherein the second chip is stacked on the first chip in a stepped manner; the electrical connection assembly comprises a first bonding wire connected to a second bonding wire in series, wherein a plurality of bonding pads are provided on upper surface edges of the circuit board, the first chip and the second chip at the same side, a bonding pad of the first chip and a bonding pad of the circuit board are electrically connected by the first bonding wire, and a bonding pad of the second chip and the bonding pad of the first chip are electrically connected by the second bonding wire; the circuit board, the resin spacer, the first chip, and the second chip are adhered together by an adhesive layer; the resin spacer, the first chip, the second chip, the electrical connection assembly, and the adhesive layer are sealed on the circuit board by the plastic packaging material; and the resin spacer has a base material of a fiber glass fabric, a weight percent of the fiber glass fabric is 10-60 wt %, and the resin spacer further comprises: 8-40 wt % of epoxy resin, 10-30 wt % of quartz powder, 2-10 wt % of aluminum oxide, 1-8 wt % of calcium oxide, and 1-8 wt % of curing agent.

2. The step-type stacked chip packaging structure according to claim 1, wherein the resin spacer has the base material of the fiber glass fabric, the weight percent of the fiber glass fabric is 40-60 wt %, and the resin spacer further comprises: 30-40 wt % of the epoxy resin, 10-20 wt % of the quartz powder, 5-10 wt % of the aluminum oxide, 2-8 wt % of the calcium oxide, and 4-8 wt % of the curing agent.

3. The step-type stacked chip packaging structure according to claim 2, wherein the epoxy resin is at least one selected from the group of a phosphating epoxy resin, a biphenyl epoxy resin, a bisphenol epoxy resin, a novolac epoxy resin, a glycerin epoxy resin, an O-methyl novolac epoxy resin, a naphthol epoxy resin, and a dicyclopentadiene epoxy resin, and the curing agent is at least one selected from the group of aliphatic amines, alicyclic amines, aromatic amines, polyamides, dicyandiamides, and imidazole compounds.

4. The step-type stacked chip packaging structure according to claim 2, wherein the resin spacer has a thickness of 0.07-0.13 mm, wherein the glass fiber fabric has a mesh size of 100-200 mesh, wherein the quartz powder has a mesh size of 200-400 mesh, the aluminum oxide has a mesh size of 400-600 mesh, and the calcium oxide has a mesh size of 200-400 mesh.

5. The step-type stacked chip packaging structure according to claim 2, wherein the resin spacer further comprises a pigment, with a weight percent of 1-3 wt %, wherein the pigment is at least one selected from the group of white carbon black and pearl powder.

6. The step-type stacked chip packaging structure according to claim 2, wherein at least one chips are stacked on the second chip in the stepped type, the plurality of bonding pads on adjacent chips are electrically connected through bonding wires, and adjacent bonding wires are connected in series.

7. The step-type stacked chip packaging structure according to claim 1, wherein the epoxy resin is at least one selected from the group of a phosphating epoxy resin, a biphenyl epoxy resin, a bisphenol epoxy resin, a novolac epoxy resin, a glycerin epoxy resin, an O-methyl novolac epoxy resin, a naphthol epoxy resin, and a dicyclopentadiene epoxy resin, and the curing agent is at least one selected from the group of aliphatic amines, alicyclic amines, aromatic amines, polyamides, dicyandiamides, and imidazole compounds.

8. The step-type stacked chip packaging structure according to claim 7, wherein the resin spacer has a thickness of 0.07-0.13 mm, wherein the glass fiber fabric has a mesh size of 100-200 mesh, wherein the quartz powder has a mesh size of 200-400 mesh, the aluminum oxide has a mesh size of 400-600 mesh, and the calcium oxide has a mesh size of 200-400 mesh.

9. The step-type stacked chip packaging structure according to claim 7, wherein the resin spacer further comprises a pigment, with a weight percent of 1-3 wt %, wherein the pigment is at least one selected from the group of white carbon black and pearl powder.

10. The step-type stacked chip packaging structure according to claim 7, wherein at least one chips are stacked on the second chip in the stepped type, the plurality of bonding pads on adjacent chips are electrically connected through bonding wires, and adjacent bonding wires are connected in series.

11. The step-type stacked chip packaging structure according to claim 1, wherein the resin spacer has a thickness of 0.07-0.13 mm, wherein the glass fiber fabric has a mesh size of 100-200 mesh, wherein the quartz powder has a mesh size of 200-400 mesh, the aluminum oxide has a mesh size of 400-600 mesh, and the calcium oxide has a mesh size of 200-400 mesh.

12. The step-type stacked chip packaging structure according to claim 11, wherein the resin spacer further comprises a pigment, with a weight percent of 1-3 wt %, wherein the pigment is at least one selected from the group of white carbon black and pearl powder.

13. The step-type stacked chip packaging structure according to claim 11, wherein at least one chips are stacked on the second chip in the stepped type, the plurality of bonding pads on adjacent chips are electrically connected through bonding wires, and adjacent bonding wires are connected in series.

14. The step-type stacked chip packaging structure according to claim 1, wherein the resin spacer further comprises a pigment, with a weight percent of 1-3 wt %, wherein the pigment is at least one selected from the group of white carbon black and pearl powder.

15. The step-type stacked chip packaging structure according to claim 14, wherein at least one chips are stacked on the second chip in the stepped type, the plurality of bonding pads on adjacent chips are electrically connected through bonding wires, and adjacent bonding wires are connected in series.

16. The step-type stacked chip packaging structure according to claim 1, wherein at least one chips are stacked on the second chip in the stepped manner, the plurality of bonding pads on adjacent chips are electrically connected through bonding wires, and adjacent bonding wires are connected in series.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The present invention will be further described hereinafter in conjunction with the drawing and embodiments.

(2) FIG. 1 is a section view of a step-type stacked chip packaging structure based on a resin spacer;

(3) The reference designators in FIG. 1 are: 1: plastic packaging material, 2: circuit board, 3: resin spacer, 4: first chip, 5: second chip, 6: electrical connection assembly, 61: first bonding wire, 62: second bonding wire, and 7: adhesive layer.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(4) Hereinafter, the present invention is further described in detail in conjunction with the FIGURE. The FIGURE is a simplified schematic diagram, which merely illustrates a basic structure of the present invention in a schematic manner, and it only shows the constitutions related to the present invention.

Embodiment 1

(5) The present embodiment provides a step-type stacked chip packaging structure based on a resin spacer, as shown in FIG. 1. The step-type stacked chip packaging structure includes: plastic packaging material 1, circuit board 2, resign spacer 3, first chip 4, second chip 5, and electrical connection assembly 6.

(6) The resin spacer 3, the first chip 4, and the second chip 5 are stacked on the circuit board 2 in respectively, the second chip 5 is stacked on the first chip 4 in a stepped manner, which does not obstruct the bonding of a bonding pad of the first chip 4. The resin spacer 3 protects an ultra-thin chip from cracking caused by unevenness of the circuit board 2.

(7) The electrical connection assembly 6 includes a first bonding wire 61 that is connected in series with a second bonding wire 62. Upper surface edges of the circuit board 2, the first chip 4 and the second chip 5 are provided with a plurality of bonding pads at the same side. For example, the plurality of bonding pads are arranged on upper surfaces of the circuit board 2, the first chip 4, and the second chip 5 at the same side, respectively, to form at least one row. A bonding pad of the first chip 4 and a bonding pad of the circuit board 2 are electrically connected by the first bonding wire 61, and a bonding pad of the second chip 5 and the bonding pad of the first chip 4 are electrically connected by the second bonding wire 62.

(8) The stacked chip packaging structure further includes a plurality of adhesive layers 7 that are respectively located between the circuit board 2 and the resin spacer 3, between the first chip 4 and the resin spacer 3, and between the first chip 4 and the second chip 5, such that the circuit board 2, the resin spacer 3, the first chip 4 and the second chip 5 are adhered together. The plurality of adhesive layers 7 in the present embodiment are adhesive and insulating films. The adhesive layers 7 are pre-attached to the back surfaces of the resin spacer 3, the first chip 4, and the second chip 5, respectively, before stacking and assembling; each of the adhesive layers 7 and the back surfaces of the corresponding components approximately have the same length and width. A thickness of the adhesive layer 7 is preferably 10-25 μm.

(9) The resin spacer 3, the first chip 4, the second chip 5, the electrical connection assembly 6, and the adhesive layer 7 are sealed on the circuit board 2 by the plastic packaging material 1.

(10) The resin spacer 3 uses a fiber glass fabric as a base material, the weight percent of the fiber glass fabric is 10-60 wt %, and the following components are attached to the fiber glass fabric as a percentage by the total weight of the resin spacer 3: 8-40 wt % of epoxy resin, 10-30 wt % of quartz powder, 2-10 wt % of aluminum oxide, 1-8 wt % of calcium oxide, and 1-8 wt % of curing agent.

(11) Preferably, the resin spacer 3 uses the fiber glass fabric as the base material, the weight percent of the fiber glass fabric is 40-60 wt %, and the following components are attached to the fiber glass fabric as a percentage by the total weight of the resin spacer 3: 30-40 wt % of epoxy resin, 10-20 wt % of quartz powder, 5-10 wt % of aluminum oxide, 2-8 wt % of calcium oxide, and 4-8 wt % of curing agent.

(12) Preferably, the resign spacer used for chip stacking and packaging further includes a pigment, the weight percent of the pigment is 1-3 wt %, and the pigment is preferably at least one of white carbon black and pearl powder.

(13) Preferably, the epoxy resin is at least one selected from a phosphating epoxy resin, a biphenyl epoxy resin, a bisphenol epoxy resin, a novolac epoxy resin, a glycerin epoxy resin, an O-methyl novolac epoxy resin, a naphthol epoxy resin, and a dicyclopentadiene epoxy resin.

(14) Preferably, the mesh size of the glass fiber fabric is 100-200 mesh (e.g., 100 mesh, 150 mesh, 200 mesh), the mesh size of the quartz powder is 200-400 mesh (e.g., 200 mesh, 300 mesh, 400 mesh), the mesh size of the aluminum oxide is 400-600 mesh (e.g., 400 mesh, 500 mesh, 600 mesh), and the mesh size of the calcium oxide is 200-400 mesh (e.g., 200 mesh, 300 mesh, 400 mesh).

(15) Preferably, the curing agent is at least one selected from aliphatic amines, alicyclic amines, aromatic amines, polyamides, dicyandiamides, and imidazole compounds.

(16) Preferably, the resin spacer has a thickness of 0.07-0.13 mm (e.g., 0.07 mm, 0.1 mm, 0.13 mm).

(17) Preferably, one or more layers of chips are stacked above the second chip 5 in a stepped manner, bonding pads on adjacent chips are electrically connected through bonding wires, and the adjacent bonding wires are connected in series.

Embodiment 2

(18) The present embodiment further provides a preparation process of the step-type stacked chip packaging structure based on the resin spacer, which includes the following steps: adhering the adhesive film to the back surface of the resin spacer, and then cutting the resin spacer to obtain the resin spacer adhered with the adhesive film of the required size; providing a circuit board, a first chip, and a second chip, stacking the resin spacer, the first chip, and the second chip on the circuit board, respectively, stacking the second chip on the first chip in a stepped manner, and adhering the circuit board, the resin spacer, the first chip, and the second chip together through the adhesive film; electrically connecting a bonding pad of the first chip and a bonding pad of the circuit board by using the first bonding wire, and electrically connecting a bonding pad of the second chip and the bonding pad of the first chip by using the second bonding wire, connecting the first bonding wire and the second bonding wire in series; and sealing the resin spacer, the first chip, the second chip, the first bonding wire, and the second bonding wire on the circuit board by using the plastic packaging material.

(19) At present, the preparation method of the silicon-based spacer applied for the stacked chip packaging structure is: providing a wafer, and adhering a protection film to a front surface of the wafer; backgrinding the back surface of the wafer by using a polisher to a required thickness, where the back surface is not adhered with the protection film; adhering an adhesive tape to the back surface of the wafer, and fixing the wafer to a substrate; tearing off the protection film on the back surface, and cutting it to a required size by using a cutter; and curing the adhesive tap by ultraviolet (UV) radiation. Accordingly, compared with the silicon-based spacer, the preparation of the resin spacer with a small size applied to the stacked chip packaging structure no longer require the use of a film laminator, a thinning grinder, and other apparatuses forming, and reduces the production cost, shortens the manufacturing cycle, and enhances the reliability of the stacking and packaging.

(20) The preparation method of the resin spacer includes the following steps:

(21) S1: mixing: adding 8-40 parts by weight of epoxy resin, 10-30 parts by weight of quartz powder, 2-10 parts by weight of aluminum oxide, and 1-8 parts by weight of calcium oxide into a solvent, stirring for dissolving them, adding 1-8 parts by weight of curing agent, and dispersing them uniformly to obtain a resin gelatinous solution;

(22) S2: impregnating: impregnating 10-60 parts by weight of the fiber glass fabric into the prepared resin gelatinous solution to obtain an impregnated fabric, and controlling an impregnating amount to be 50-70 g/m.sup.2 (e.g., 50 g/m.sup.2, 60 g/m.sup.2, 70 g/m.sup.2);

(23) S3: partially curing: drying the impregnated fabric at 70-120° C. (e.g., 70° C., 100° C., 120° C.), and controlling a pre-curing degree at 30-50% (e.g., 30%, 40%, 50%) to obtain a prepreg;

(24) S4: stacking and pressing: laminating a plurality of prepregs, then heating them at a temperature of 150-180° C. (e.g., 150° C., 160° C., 180° C.), pressing them at a pressure of 3-10 MPa simultaneously, stopping the heating after 8-12 h (e.g., 8 h, 10 h, 12 h) of heat preservation, and obtaining a resign spacer with a certain thickness after cooling.

(25) Preferably, the solvent is at least one selected from acetone, butanone, ethyl acetate, butyl acetate, ethanol, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone.

(26) Based on the above ideal embodiments and descriptions of the present invention, the person skilled in the prior art can make various changes and modifications without departing from the scope of the technical concept of the present invention. The technical scope of the present invention is not limited to the contents of the description, and the technical scope must be determined according to the scope of the claims.