Manufacturing method of ultrathin packaging structure
阅读说明:本技术 超薄封装结构的制作方法 (Manufacturing method of ultrathin packaging structure ) 是由 孔德荣 阙燕洁 于 2019-04-28 设计创作,主要内容包括:本发明提供了一种超薄封装结构的制作方法,在注塑阶段,注入大量液态塑封料,使得液态塑封料充分流动至待封装半导体结构的各个间隙后再固化,避免空气间隙产生;之后再进行固态塑封料的厚度减薄。好处在于,既满足了超薄封装结构中固态塑封料无空气间隙的需求,又成本较低。(The invention provides a manufacturing method of an ultrathin packaging structure, which is characterized in that a large amount of liquid plastic packaging material is injected in an injection molding stage, so that the liquid plastic packaging material is solidified after fully flowing to each gap of a semiconductor structure to be packaged, and air gaps are avoided; and then thinning the solid plastic package material. The method has the advantages of meeting the requirement that the solid plastic package material in the ultrathin packaging structure has no air gap and being low in cost.)
1. A manufacturing method of an ultrathin packaging structure is characterized by comprising the following steps:
providing a semiconductor structure to be packaged, and carrying out injection molding on the semiconductor structure to be packaged to form an initial packaging structure; in the injection molding, the injection amount of the liquid plastic packaging material is greater than that of the solid plastic packaging material in the ultrathin packaging structure, so that the liquid plastic packaging material is solidified after flowing fully;
and thinning the solid plastic package material in the initial packaging structure to form the ultrathin packaging structure.
2. The method for manufacturing the ultrathin packaging structure as claimed in claim 1, wherein the semiconductor structure to be packaged comprises a lead frame and a chip after bonding; the lead frame comprises an outer lead, the chip comprises a bonding pad, and the outer lead is bonded with the bonding pad through a lead.
3. The method for manufacturing the ultrathin packaging structure as claimed in claim 1, wherein the semiconductor structure to be packaged comprises a lead frame and a chip after bonding; the lead frame comprises an outer pin, the chip comprises a bonding pad, and the outer pin is bonded with the bonding pad through a copper clamp.
4. The method for manufacturing the ultra-thin package structure as claimed in any one of claims 1 to 3, wherein the thickness reduction of the solid molding compound is performed by mechanical grinding.
5. The method for manufacturing the ultra-thin package structure of claim 4, wherein the mechanical grinding is grinding by a grinding wheel.
6. The method for manufacturing the ultra-thin package structure of claim 1, wherein the solid molding compound is made of epoxy resin, polyimide resin, benzocyclobutene resin, polybenzoxazole resin, polybutylene terephthalate, polycarbonate, polyethylene terephthalate, polyethylene, polypropylene, polyolefin, polyurethane, polyolefin, polyethersulfone, polyamide, polyurethane, ethylene-vinyl acetate copolymer, or polyvinyl alcohol.
7. The method of claim 1, wherein the thickness of the initial package structure is greater than 100 μm.
8. The method for manufacturing the ultra-thin package structure of claim 6, wherein in the step of injection molding, the temperature range of the mold for curing is as follows: 170-180 ℃, and/or the injection rate range of the liquid plastic package material is as follows: 0.1 mm/s-5 mm/s.
9. The method for manufacturing the ultra-thin package structure of claim 2, wherein the distance between the highest point of the lead and the upper surface of the chip is in the range of: 20-35 μm; the distance range between the upper surface of the ultrathin packaging structure and the upper surface of the chip is as follows: 50-80 μm.
10. The method of claim 1, wherein the ultra-thin package structure has a thickness of less than 100 μm.
Technical Field
The invention relates to the technical field of chip packaging, in particular to a manufacturing method of an ultrathin packaging structure.
Background
In recent years, with the trend of miniaturization of devices, there is a demand for a low package height, i.e., an ultra-thin package, of a package structure in the industry.
To meet the above requirements, one solution is to use a compression plastic package technique. However, the compression molding technique requires high cost of equipment and materials, and cannot be applied in large scale.
The other solution is to adopt an injection molding plastic package technology. However, after the ultra-thin package is completed by the conventional injection molding process, air gaps are often found in the solid-state package material, which affects the yield and performance reliability of the package structure.
In view of the above, the present invention provides a novel method for fabricating an ultra-thin package structure, which is capable of fabricating an ultra-thin package structure with high yield and reliable performance in a low-cost manner.
Disclosure of Invention
The invention aims to provide a manufacturing method of an ultrathin packaging structure, which is used for manufacturing the ultrathin packaging structure with high yield and reliable performance in a low-cost mode.
In order to achieve the above object, the present invention provides a method for manufacturing an ultra-thin package structure, comprising:
providing a semiconductor structure to be packaged, and carrying out injection molding on the semiconductor structure to be packaged to form an initial packaging structure, wherein in the injection molding, the injection amount of the liquid plastic packaging material is greater than the amount of the solid plastic packaging material in the ultrathin packaging structure, so that the liquid plastic packaging material is solidified after flowing fully;
and thinning the solid plastic package material in the initial packaging structure to form the ultrathin packaging structure.
Optionally, the semiconductor structure to be packaged includes a lead frame and a chip after bonding; the lead frame comprises an outer lead, the chip comprises a bonding pad, and the outer lead is bonded with the bonding pad through a lead.
Optionally, the semiconductor structure to be packaged includes a lead frame and a chip after bonding; the lead frame comprises an outer pin, the chip comprises a bonding pad, and the outer pin is bonded with the bonding pad through a copper clamp.
Optionally, the thickness reduction of the solid molding compound is performed by mechanical grinding.
Optionally, the mechanical grinding is wheel grinding.
Optionally, the solid molding compound is made of epoxy resin, polyimide resin, benzocyclobutene resin, polybenzoxazole resin, polybutylene terephthalate, polycarbonate, polyethylene terephthalate, polyethylene, polypropylene, polyolefin, polyurethane, polyolefin, polyethersulfone, polyamide, polyurethane, ethylene-vinyl acetate copolymer, or polyvinyl alcohol.
Optionally, the thickness of the initial package structure is greater than 100 μm.
Optionally, in the injection molding step, the temperature range of the mold for curing is as follows: 170-180 ℃, and/or the injection rate range of the liquid plastic package material is as follows: 0.1 mm/s-5 mm/s.
Optionally, the distance between the highest point of the lead and the upper surface of the chip is in a range of: 20-35 μm; the distance range between the upper surface of the ultrathin packaging structure and the upper surface of the chip is as follows: 50-80 μm.
Optionally, the thickness of the ultra-thin package structure is less than 100 μm.
Compared with the prior art, the invention has the beneficial effects that:
1) In the injection molding stage, a large amount of liquid plastic packaging material is injected, so that the liquid plastic packaging material is solidified after fully flowing to each gap of the semiconductor structure to be packaged, and air gaps are avoided; and then thinning the solid plastic package material. Has the advantages that: the requirement that the solid plastic packaging material in the ultrathin packaging structure has no air gap is met, and the cost is low.
2) In one alternative, the semiconductor structure to be packaged comprises a lead frame and a chip after being bonded; the lead frame comprises an outer lead, the chip comprises a bonding pad, and the outer lead is bonded with the bonding pad through a lead. In another alternative, the lead frame includes outer leads, and the chip includes a bonding pad, the outer leads being bonded to the bonding pad by copper clips. In other alternatives, the semiconductor structure to be packaged may further include a substrate and a chip after bonding. The manufacturing method of the ultrathin packaging structure can be used for various bonding processes and semiconductor structures to be packaged with various outer pins, and is high in compatibility.
3) In an alternative, the thickness reduction of the solid molding compound is performed by mechanical grinding. Preferably, the mechanical grinding is wheel grinding. The mechanical grinding, especially the grinding wheel grinding, has lower cost.
4) In the alternative, the solid plastic package material is made of epoxy resin, polyimide resin, benzocyclobutene resin, polybenzoxazole resin, polybutylene terephthalate, polycarbonate, polyethylene terephthalate, polyethylene, polypropylene, polyolefin, polyurethane, polyolefin, polyethersulfone, polyamide, polyurethane, ethylene-vinyl acetate copolymer or polyvinyl alcohol. In other words, any kind of liquid plastic packaging material which needs to be solidified by changing the temperature can be encapsulated by adopting the scheme of firstly injecting a large amount of liquid plastic packaging material to fully flow and solidify and then thinning the solid plastic packaging material.
5) In an alternative, the thickness of the initial package structure is greater than 100 μm. Research shows that under the condition that the liquid plastic packaging material flows sufficiently, the thickness of an initial packaging structure formed after curing is larger than 100 mu m.
6) In an alternative scheme, in the injection molding step, the temperature range of the mold for curing is as follows: 170-180 ℃. For epoxy resin or similar plastic packaging material, the complete curing can be ensured by combining the temperature of the die.
7) In an alternative scheme, in the injection molding step, the injection rate range of the liquid plastic package material is as follows: 0.1 mm/s-5 mm/s. The injection rate is combined with a mold with the temperature ranging from 170 ℃ to 180 ℃, so that the liquid plastic packaging material of the epoxy resin or the similar material can be ensured to be solidified at the same time or after the liquid plastic packaging material fully flows to each gap between the chip and the lead frame, and the generation of air gaps is avoided.
8) In an alternative, the distance between the highest point of the lead and the upper surface of the chip is in the range of: 20-35 μm; the distance range between the upper surface of the ultrathin packaging structure and the upper surface of the chip is as follows: 50-80 μm. The 50-80 μm can not only meet the requirement of not exposing the lead, but also fully fix and protect the lead.
9) In the alternative, for copper clip bonding, the distance between the upper surface of the ultrathin packaging structure and the upper surface of the chip is 50-80 μm. 50-80 μm can not only prevent the copper clip from being exposed, but also fully fix and protect the copper clip.
10) In an alternative, the thickness of the ultra-thin package structure is less than 100 μm. The above thicknesses satisfy the demand for ultra-thin packaging in the industry.
Drawings
Fig. 1 is a flowchart corresponding to a method for manufacturing an ultra-thin package structure according to an embodiment of the invention;
fig. 2 to 7 are intermediate schematic diagrams corresponding to the flow in fig. 1.
To facilitate an understanding of the invention, all reference numerals appearing in the invention are listed below:
lead frame 11 of semiconductor structure 10 to be packaged
Base
Initial packaging structure 1 of solid
Ultra-thin packaging structure 2
Detailed Description
The inventor discovers that the injection molding and plastic packaging process comprises the following steps: when the thickness of the packaging structure is larger than 100 micrometers, the amount of the injected liquid plastic packaging material is larger, the fluidity of the plastic packaging material can uniformly cover the surface of the chip and can well wrap the metal lead, and the damage possibly caused by the exposure of the metal lead outside is effectively avoided; with the decrease of the amount of the injected liquid molding compound, an air gap occurs in the solid molding compound, and the yield of the package structure is gradually reduced.
Through analysis, it is found that one reason for the generation of the air gap is: since the injection mold has a high temperature and the injected liquid molding compound has a low temperature, if a small amount of liquid molding compound is injected to realize ultra-thin packaging, the injected liquid molding compound is solidified before flowing to each gap of the semiconductor structure to be packaged.
Based on the above analysis, the present invention proposes: in the injection molding stage, a large amount of liquid plastic packaging material is injected, so that the liquid plastic packaging material fully flows to each gap of the semiconductor structure to be packaged and is solidified, and air gaps are avoided; and then thinning the solid plastic package material. Therefore, the requirements of low packaging height and no air gap of the solid plastic packaging material are met, and the cost is lower.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
Fig. 1 is a flowchart corresponding to a method for manufacturing an ultra-thin package structure according to an embodiment of the invention. Fig. 2 to 7 are intermediate schematic diagrams corresponding to the flow in fig. 1.
First, referring to step S1 in fig. 1 and fig. 2 to 5, providing a semiconductor structure 10 to be packaged, and injection molding the semiconductor structure 10 to be packaged to form an initial package structure 1; in the injection molding, the injection amount of the liquid molding compound is greater than the amount of the solid molding compound 15' (shown in fig. 6 and 7) in the ultra-thin package structure 2, so that the liquid molding compound is solidified after flowing sufficiently.
In one alternative, referring to fig. 2, a semiconductor structure 10 to be packaged includes a lead frame 11 and a
The material of the
The
The backside of the
In a specific implementation process, in the semiconductor structure 10 to be packaged, as shown in fig. 2, the outer leads 111 and the
In other alternatives, the semiconductor structure 10 to be packaged may also include a substrate and a chip after bonding. The invention is not limited to the specific structure of the semiconductor structure 10 to be packaged.
Next, referring to fig. 4 and 5, the semiconductor structure 10 to be packaged is placed in a mold, and in one example, the mold is heated to a temperature range of: 170-180 ℃; then, a large amount of liquid molding compound at normal temperature is injected into the mold, and the injected liquid molding compound can be but is not limited to epoxy resin.
In one example, the height of the mold cavity is greater than 100 μm, which ensures that the liquid molding compound is solidified while or after flowing sufficiently into the respective gaps between the
In one example, the injection rate range of the liquid molding compound is: 0.1 mm/s-5 mm/s. It will be appreciated that for a certain height of the mould cavity: if the liquid plastic packaging material is injected too slowly, the liquid plastic packaging material can not flow to each gap and is solidified; if the liquid molding compound is injected too fast, it will not be time to wet some gaps, and air gaps will appear in the solidified
For other molding compounds, such as polyimide resins, benzocyclobutene resins, polybenzoxazole resins, polybutylene terephthalate, polycarbonate, polyethylene terephthalate, polyethylene, polypropylene, polyolefins, polyurethanes, polyolefins, polyethersulfones, polyamides, polyurethanes, ethylene vinyl acetate copolymers, or polyvinyl alcohol, the appropriate mold cavity height, mold temperature, and injection molding rate can be selected to allow sufficient flow and then cure.
Thereafter, referring to step S2 in fig. 1 and fig. 6 and 7, the thickness of the
The thinned
In this step, the thickness of the
In one alternative, the mechanical grinding is wheel grinding.
The solid
Referring to fig. 6, the distance between the upper surface of the ultra-thin package structure 2 and the upper surface of the
Referring to fig. 7, the distance between the highest point of the lead 14 and the upper surface of the
The thickness of the ultra-thin package structure formed in step S2 is preferably less than 100 μm.
It can be seen that in the injection molding stage, a large amount of liquid molding compound is injected, so that the liquid molding compound is fully flowed to each gap between the
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
- 上一篇:一种医用注射器针头装配设备
- 下一篇:半导体封装方法