A fan-out stacked packaging structure using metal conductive columns and a preparation method thereof

Abstract

The present invention relates to a fan-out stacked packaging structure using metal conductive columns, wherein a plastic sealing layer and a rewiring layer are sequentially arranged from top to bottom, wherein a plurality of first chips or devices with metal contacts are plastic-sealed in the plastic sealing layer, and a plurality of metal conductive columns are also plastic-sealed at the upper contacts of the rewiring layer in the plastic sealing layer, wherein one end of the metal conductive column is flush with the surface of the plastic sealing layer, and the other end is in contact with the upper contacts of the rewiring layer, a tin ball is arranged on the lower contacts of the rewiring layer, and a second chip or device is also arranged at the exposed ends of the metal conductive columns on the upper surface of the plastic sealing layer. The present invention also discloses a method for preparing such a fan-out stacked packaging structure. The design scheme of the present invention greatly improves the flexibility and convenience of packaging, simplifies the entire process, and saves costs, compared with the method of making copper columns using a more complicated multi-step photolithography process used in the traditional method.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging, and in particular to a fan-out stacked packaging structure using metal conductive columns and a preparation method thereof. Background Art

[0002] The multifunctionality and miniaturization of semiconductor chips have become a major trend, and the types and number of chips that need to be integrated and packaged together are also increasing. For example, applications such as PA / PMU / IoT often require chips with different functions (bare wafers or passive components) to be assembled together to achieve a single package with certain functions, thereby forming a package module or sub-module.

[0003] The widely used fan-out packaging is to rewire the plastic package composed of the chips (including passive components and bare chips) that have been plastic-sealed together to achieve interconnection packaging between components. This type of packaging method has problems such as difficulty in controlling warpage, poor precision, large packaging area, and low reliability when dealing with the integrated packaging of a large number of complex and diverse chips and passive components. In addition, the copper pillars used for interconnection between the upper and lower chips are made through a process of photolithography and electroplating, which has many process steps, complex procedures and relatively high costs. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to solve the problem that the existing fan-out type multi-layer chip packaging method is to prepare a rewiring layer and a plastic packaging layer on the plastic packaging layer to achieve the purpose of multi-layer packaging, but when integrating and packaging a large number of complex and diverse chips and passive devices, there are problems such as difficulty in controlling warpage, poor precision, large packaging area, and low reliability.

[0005] Technical solution: To solve the above problems, the present invention adopts the following technical solution:

[0006] A fan-out stacked packaging structure using metal conductive columns, wherein a plastic sealing layer and a rewiring layer are sequentially arranged from top to bottom, wherein a plurality of first chips or devices with metal contacts are sealed in the plastic sealing layer, and a plurality of metal conductive columns are also sealed in the plastic sealing layer at positions corresponding to upper contacts of the rewiring layer, wherein one end of the metal conductive column is flush with the surface of the plastic sealing layer and the other end is in contact with the upper contact of the rewiring layer, a solder ball is arranged on the lower contact of the rewiring layer, and a second chip or device is also arranged on the upper surface of the plastic sealing layer corresponding to the exposed end of the metal conductive column.

[0007] Furthermore, the metal conductive column is a cylindrical copper column or silver column (or other types of metal materials), and has contact parts at both ends that can be connected to metal contacts. The diameter of the contact part is 1 to 2 μm smaller than the middle diameter of the metal conductive column, and the roughness of the end faces at both ends is about 1 μm.

[0008] If the diameter does not meet the requirements, there will be errors in the contact with the contacts, resulting in unstable installation. At the same time, the design of the end face roughness is not less than 1μm, so that the contact part and the contact have a certain friction to prevent the metal conductive column from slipping out of the contact during installation. However, due to the existence of roughness, the contact between the metal conductive column and the contact is not smooth, and there will be certain differences in the current collection. Therefore, it is necessary to control the end face diameter of the metal conductive column and the contact.

[0009] Furthermore, the rewiring layer includes a plurality of dielectric layers and metal interconnection layers.

[0010] A method for preparing a fan-out stacked package structure using metal conductive pillars comprises the following steps:

[0011] 1) Adhere a temporary bonding adhesive to the surface of the temporary carrier sheet;

[0012] 2) using a thin film process to make a rewiring layer on the surface of the temporary bonding adhesive obtained in step (1);

[0013] 3) attaching the first chip or device to be packaged on the rewiring layer, with the device surface of the first chip facing the rewiring layer and the metal pins of the first chip connected to the corresponding contacts on the rewiring layer;

[0014] 4) Making a metal conductive column, grinding the metal edge to form a cylindrical conductive column, and at the same time roughening the two end surfaces of the metal conductive column, and grinding the edges of the contact parts close to the two end surfaces;

[0015] 5) On the rewiring layer corresponding to the contact point, place the prepared metal conductive column on the corresponding contact point by screen printing;

[0016] 6) The metal conductive pillars attached to the rewiring layer, the first chip and the device are integrally plastic-encapsulated to form a plastic-encapsulation layer, and the thickness of the plastic-encapsulation layer is reduced to expose the end surface of the metal conductive pillar away from the rewiring layer, so that the end surface of the metal conductive pillar away from the rewiring layer and the end surface of the plastic-encapsulation layer away from the rewiring layer are in the same plane;

[0017] 7) Using laser or thermal stripping to separate the temporary carrier sheet from the plastic package body on it, and remove the temporary bonding glue, so that the rewiring layer on the package body is exposed;

[0018] 8) Planting balls on the rewiring layer of the plastic package and completing solder ball welding;

[0019] 9) attaching the remaining packaged second chip with conductive sheet and solder joints to the end surface of the plastic packaging layer away from the rewiring layer corresponding to the end surface of the metal conductive column away from the rewiring layer;

[0020] 10) The packaged chips are cut into units to obtain individual package units.

[0021] The second chip is directly disposed on the surface of the plastic packaging layer through metal conductive pillars, thus eliminating a rewiring layer.

[0022] Furthermore, after step 6), a rewiring layer may be fabricated again on the plastic packaging layer using a thin film process, and then chips or devices may be arranged on the rewiring layer to achieve stacking of more complex chips.

[0023] If you need to stack more than two layers of more complex chips or more than three layers of chips, you can use this method, using two layers of rewiring layers or two layers of rewiring layers and two layers of plastic packaging layers. The chip on the outermost layer is directly mounted on the outer plastic packaging layer through the contacts of the metal conductive pillars / rewiring layer.

[0024] Furthermore, the temporary bonding adhesive may be a thermal stripping adhesive, a UV adhesive or a laser debonding adhesive.

[0025] Furthermore, the temporary carrier sheet is a quartz sheet, a glass sheet, a metal sheet, a silicon sheet, or a ceramic sheet.

[0026] Furthermore, in the step 9), the completed package is placed on another temporary carrier sheet before attachment, and is bonded in the middle with temporary bonding glue, with the solder ball surface facing the temporary carrier sheet; after attachment, the temporary carrier sheet and temporary bonding glue are removed again.

[0027] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0028] Compared with the traditional method of using a relatively complex multi-step photolithography process to manufacture metal conductive pillars, the present invention greatly improves the flexibility and convenience of packaging, simplifies the entire process, and saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a state diagram after the packaging process step 1) of the present invention is completed;

[0030] Figure 2 This is a state diagram after the packaging process step 2) of the present invention is completed;

[0031] Figure 3 This is a state diagram after the packaging process step 5) of the present invention is completed;

[0032] Figure 4This is a state diagram after the plastic sealing layer is formed in step 6) of the packaging process of the present invention;

[0033] Figure 5 This is a state diagram of the packaging process of the present invention in step 6) thinning the thickness of the plastic packaging layer so that the end surface of the metal conductive column away from the rewiring layer is exposed;

[0034] Figure 6 This is a state diagram after the packaging process step 7) of the present invention is completed;

[0035] Figure 7 This is a state diagram after the packaging process step 8) of the present invention is completed;

[0036] Figure 8 This is a state diagram after the packaging process step 91) of the present invention is completed;

[0037] Fig. 9 This is a state diagram after the packaging process step 9) of the present invention is completed by attaching the second chip or device;

[0038] Fig.10 This is a state diagram after the packaging process step 92) of the present invention is completed;

[0039] Fig.11 A schematic diagram of the packaging process of the present invention using two rewiring layers to perform more complex chip packaging;

[0040] In the figure, 100 is a temporary carrier sheet, 110 is a temporary bonding adhesive, 120 is a rewiring layer, 130 is a first chip or device with metal contacts, 140 is a metal conductive column, 150 is a plastic encapsulation layer, 160 is a solder ball, and 170 is a second chip or device. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0042] Example 1

[0043] A fan-out stacked packaging structure using metal conductive columns, wherein a plastic encapsulation layer and a rewiring layer 120 are sequentially arranged from top to bottom, a plurality of first chips or devices 130 with metal contacts are encapsulated in the plastic encapsulation layer 150, a plurality of metal conductive columns 140 are also encapsulated in the plastic encapsulation layer 150 at the upper contacts corresponding to the rewiring layer 120, one end of the metal conductive column 140 is flush with the surface of the plastic encapsulation layer 150, and the other end is in contact with the upper contact of the rewiring layer 120, a solder ball 160 is arranged on the lower contact of the rewiring layer 120, and a second chip or device 170 is also arranged on the upper surface of the plastic encapsulation layer 150 corresponding to the exposed end of the metal conductive column 140.

[0044] The metal conductive column 140 is a cylindrical copper column or silver column, and has contact portions at both ends that can be connected to metal contacts. The diameter of the contact portion is 1-2 μm smaller than the middle diameter of the metal conductive column, and the roughness of the end surfaces at both ends is about 1 μm.

[0045] If the diameter does not meet the requirements, there will be errors in the contact with the contacts, resulting in unstable installation. At the same time, the design of the end face roughness is not less than 1μm, so that the contact part and the contact have a certain friction to prevent the metal conductive column from slipping out of the contact during installation. However, due to the existence of roughness, the contact between the metal conductive column and the contact is not smooth, and there will be certain differences in the current collection. Therefore, it is necessary to control the end face diameter of the metal conductive column and the contact.

[0046] The rewiring layer 120 includes a plurality of dielectric layers and metal interconnect layers.

[0047] Example 2

[0048] A method for preparing a fan-out stacked package structure using metal conductive pillars comprises the following steps:

[0049] 1) If Figure 1 , adhering a temporary bonding adhesive 110 on the surface of the temporary carrier sheet 100;

[0050] 2) If Figure 2 , using a thin film process to make a rewiring layer 120 on the surface of the temporary bonding adhesive 110 obtained in step (1);

[0051] 3) attaching the first chip or device 130 to be packaged on the rewiring layer 120, with the device surface of the first chip 130 facing the rewiring layer 120 and the metal pins of the first chip 130 connected to the corresponding contacts on the rewiring layer 120;

[0052] 4) Making a metal conductive column 140, grinding the metal edge to form a cylindrical conductive column, and at the same time roughening the two end surfaces of the metal conductive column, and grinding the edges of the contact parts close to the two end surfaces;

[0053] 5) If Figure 3 , on the rewiring layer 120 corresponding to the contact point, the prepared metal conductive column 140 is placed on the corresponding contact point by screen printing;

[0054] 6) If Figure 4 and 5, the metal conductive pillar 140 attached to the rewiring layer 120, the first chip and the device 130 are integrally encapsulated to form a plastic encapsulation layer 150, and the thickness of the plastic encapsulation layer 150 is thinned to expose the end surface of the metal conductive pillar 140 away from the rewiring layer 120, so that the end surface of the metal conductive pillar 140 away from the rewiring layer 120 and the end surface of the plastic encapsulation layer 150 away from the rewiring layer 120 are in the same plane;

[0055] 7) If Figure 6 , using laser or thermal stripping to separate the temporary carrier sheet 100 from the plastic package body thereon, and remove the temporary bonding adhesive 110, so that the rewiring layer 120 on the package body is exposed;

[0056] 8) If Figure 7 , planting balls on the rewiring layer 120 of the plastic package and completing solder ball welding;

[0057] 9) If Fig. 9 , attaching the remaining packaged second chip 170 with conductive sheets and solder joints to the end surface of the plastic encapsulation layer 150 away from the rewiring layer 120 corresponding to the end surface of the metal conductive column 140 away from the rewiring layer 120;

[0058] 91) Figure 8 Before attaching, the package body is placed on another temporary carrier sheet 100, and the temporary bonding adhesive 110 is used to bond the package body in the middle, and the solder ball 160 faces the temporary carrier sheet 100;

[0059] 92) Fig.10 , after attachment, the temporary carrier sheet 100 and the temporary bonding adhesive 110 are removed again;

[0060] 10) The packaged chips are cut into units to obtain individual package units.

[0061] The second chip 170 is directly disposed on the surface of the plastic packaging layer 150 through the metal conductive pillars 140 , thus eliminating the need for a rewiring layer 120 .

[0062] After step 6), a rewiring layer 120 may be fabricated again on the plastic encapsulation layer 150 by using a thin film process, and then chips or devices may be arranged on the rewiring layer 120 to achieve stacking of more complex chips.

[0063] If you need to stack more than two layers of more complex chips or more than three layers of chips, you can use this method, using two layers of rewiring layers or two layers of rewiring layers and two layers of plastic packaging layers. The chip on the outermost layer is directly mounted on the outer plastic packaging layer through the metal conductive pillars / rewiring layer contacts. Fig.11 .

[0064] Temporary bonding adhesive can be heat-peelable adhesive, UV adhesive or laser debonding adhesive.

[0065] The temporary carrier sheet is a quartz sheet, a glass sheet, a metal sheet, a silicon sheet or a ceramic sheet.

Claims

1. A fan-out stacked package structure using metal conductive pillars, characterized in that: A plastic encapsulation layer and a rewiring layer are sequentially arranged from top to bottom, a plurality of first chips or devices with metal contacts are encapsulated in the plastic encapsulation layer, a plurality of metal conductive pillars are also encapsulated in the plastic encapsulation layer at positions corresponding to upper contacts of the rewiring layer, two ends of the metal conductive pillars, one end is flush with the surface of the plastic encapsulation layer, and the other end is in contact with the upper contact of the rewiring layer, a solder ball is arranged on the lower contact of the rewiring layer, and a second chip or device is also arranged on the upper surface of the plastic encapsulation layer at positions corresponding to exposed ends of the metal conductive pillars; The metal conductive column is a cylindrical copper column or silver column, and has contact portions at both ends that can be connected to metal contacts. The diameter of the contact portion is 1-2 μm smaller than the diameter of the middle portion of the metal conductive column, and the roughness of the end surfaces at both ends is about 1 μm. The rewiring layer includes a plurality of dielectric layers and metal interconnection layers.

2. A method for preparing a fan-out stacked package structure using metal conductive pillars as claimed in claim 1, characterized in that: The following steps are involved: 1) Adhere a temporary bonding adhesive to the surface of the temporary carrier sheet; 2) using a thin film process to make a rewiring layer on the surface of the temporary bonding adhesive obtained in step (1); 3) attaching the first chip or device to be packaged on the rewiring layer, with the device surface of the first chip facing the rewiring layer and the metal pins of the first chip connected to the corresponding contacts on the rewiring layer; 4) manufacturing a metal conductive column, grinding the metal edge to form a cylindrical conductive column, and roughening the two end faces of the metal conductive column, and grinding the edges of the contact parts close to the two end faces; the metal conductive column is a cylindrical copper column or silver column, and has contact parts that can be connected to the metal contact at both ends, the diameter of the contact part is 1 to 2 μm smaller than the middle diameter of the metal conductive column, and the roughness of the end faces at both ends is about 1 μm; 5) On the rewiring layer corresponding to the contact point, place the prepared metal conductive column on the corresponding contact point by screen printing; 6) The metal conductive pillars attached to the rewiring layer, the first chip and the device are integrally plastic-encapsulated to form a plastic-encapsulation layer, and the thickness of the plastic-encapsulation layer is reduced to expose the end surface of the metal conductive pillar away from the rewiring layer, so that the end surface of the metal conductive pillar away from the rewiring layer and the end surface of the plastic-encapsulation layer away from the rewiring layer are in the same plane; 7) Using laser or thermal stripping to separate the temporary carrier sheet from the plastic package body on it, and remove the temporary bonding glue, so that the rewiring layer on the package body is exposed; 8) Planting balls on the rewiring layer of the plastic package and completing solder ball welding; 9) attaching the remaining packaged second chip with conductive sheet and solder joints to the end surface of the plastic packaging layer away from the rewiring layer corresponding to the end surface of the metal conductive column away from the rewiring layer; 10) Cut the packaged chips into units to obtain individual package units.

3. The method for preparing a fan-out stacked package structure using metal conductive pillars according to claim 2, characterized in that: After step 6), a rewiring layer can be made again on the plastic packaging layer using a thin film process, and then chips or devices are arranged on the rewiring layer to achieve multi-layer chip stacking.

4. The method for preparing a fan-out stacked package structure using metal conductive pillars according to claim 2, characterized in that: The temporary bonding adhesive can be a thermal stripping adhesive, a UV adhesive or a laser debonding adhesive.

5. The method for preparing a fan-out stacked package structure using metal conductive pillars according to claim 2, characterized in that: The temporary carrier sheet is a quartz sheet, a glass sheet, a metal sheet, a silicon sheet or a ceramic sheet.

6. The method for preparing a fan-out stacked package structure using metal conductive pillars according to claim 2, characterized in that: In the step 9), the completed package is placed on another temporary carrier sheet before attachment, and is bonded in the middle with temporary bonding glue, with the solder ball surface facing the temporary carrier sheet; after attachment, the temporary carrier sheet and temporary bonding glue are removed again.

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