CN112004318B

CN112004318B - Packaging structure and manufacturing method thereof

Info

Publication number: CN112004318B
Application number: CN202010821041.2A
Authority: CN
Inventors: 不公告发明人
Original assignee: Wuxi Xianren Zhixin Microelectronics Technology Co ltd
Current assignee: Wuxi Xianren Zhixin Microelectronics Technology Co ltd
Priority date: 2020-08-14
Filing date: 2020-08-14
Publication date: 2022-02-18
Anticipated expiration: 2040-08-14
Also published as: CN112004318A

Abstract

The invention relates to the technical field of electronic part manufacturing, in particular to a packaging structure and a manufacturing method thereof, aiming at solving the problems that in the prior art, the growth of a metal layer can be stored on the side wall of a groove, the difference between the thermal expansion coefficients of the metal layer at the side wall and a circuit board is large, the metal layer and the circuit board are easy to extrude to generate cracks when being heated and expanded during working, and the metal flange is not beneficial to the subsequent regrowth. The invention can effectively improve the packaging reliability and the yield.

Description

Packaging structure and manufacturing method thereof

Technical Field

The invention relates to the technical field of electronic part manufacturing, in particular to a packaging structure and a manufacturing method thereof.

Background

Typically, the electronic components are mounted or inserted on a Printed Circuit Board (PCB), for example, by soldering through holes on the PCB. Under the condition, the heat generated by the electronic part during working is transmitted to the outside through the air around the electronic part and the PCB, so that the self heat dissipation is realized. Because the PCB and the air have poor heat conduction capability, the structure is not beneficial to heat dissipation of the electronic part, and particularly for the electronic part with high power, the heat dissipation effect is poorer. Therefore, it is necessary to improve the heat dissipation capability of the electronic component by optimizing the assembly design of the insertion device.

In the prior art, a groove for mounting a metal flange is etched on a printed circuit board, and the metal flange is connected with the printed circuit board through a metal layer. Because the thermal expansion coefficient difference between the printed circuit board and the metal flange is large, the heat generated by the electronic part during working can cause cracks to appear between the metal layer and the printed circuit board, and even can influence the transmission of metal signals of the circuit board on the side wall of the groove, thereby causing signal delay and causing signal interference if serious.

Disclosure of Invention

Therefore, the technical problem to be solved by the present invention is to overcome the problem in the prior art that the growth of the metal layer is preserved on the side wall of the groove, the difference between the thermal expansion coefficients of the metal layer at the side wall and the circuit board is large, and the metal layer and the circuit board are easily extruded to generate cracks when being heated and expanded during operation, thereby providing a package structure and a manufacturing method thereof.

The invention provides a packaging structure, which comprises a printed circuit board, a groove arranged on the printed circuit board, a metal flange embedded in the groove, and a plurality of electronic parts arranged on the metal flange, wherein a resin layer grows on the side wall of the groove, a metal layer grows on one side of the resin layer, which is opposite to the side wall of the groove, and the metal flange is fastened in the groove by the metal layer.

Optionally, the thickness of the resin layer is greater than the thickness of the metal layer; or

The thickness of the resin layer is twice of that of the metal layer.

Optionally, there is a gap between the metal layer and the printed circuit board.

Optionally, the metal layer and the metal flange are closely connected by heating at their contact portions, the heating process having a heating zone of 100-200 ℃.

Alternatively, the printed circuit board is a single plate sized to fit the metal flange and electronics.

Optionally, a protective cover is disposed above the printed circuit board and adjacent to the metal flange, and the protective cover covers and protects the electronic component.

Optionally, the metal flange is made of copper, copper tungsten or copper molybdenum; or

The resin layer covers a portion of a sidewall of the printed circuit board.

The second scheme of the invention provides a manufacturing method based on the packaging structure, which comprises the following steps:

a groove is formed in the printed circuit board, and the size of the groove is larger than that of the metal flange;

covering a layer of resin material on the groove wall of the groove to form a resin layer, and carrying out patterning treatment to etch a window required by the electronic part lead;

covering a layer of metal material on the side wall of the resin layer opposite to the groove to form a metal layer, wherein the thickness of the metal layer and the resin layer enables the size of a notch of the groove to be matched with that of the metal flange, and the thickness of the resin layer is larger than that of the metal layer;

embedding the metal flange into the groove, and tightly connecting the metal flange with the metal layer;

manufacturing input electrodes and output electrodes distributed on two sides of a metal flange on a printed circuit board, and mounting a plurality of electronic parts on the metal flange;

connecting the electronic parts through a lead process, and connecting the input ends and the output ends of the electronic parts to input electrodes and output electrodes on a printed circuit board;

and installing a protective cover above the area provided with the electronic part.

Optionally, when the input electrode and the output electrode distributed on two sides of the metal flange are manufactured on the printed circuit board, two electrode pads are arranged below the printed circuit board at positions corresponding to the input electrode and the output electrode, and the two electrode pads are insulated from the metal flange.

Optionally, after the metal layer is formed, a portion of the resin layer is etched to form a gap between the metal layer and the printed circuit board.

The technical scheme of the invention has the following advantages:

1. the resin layer has on the recess lateral wall in the printed circuit board, and the resin layer passes through metal level and metal flange joint, because printed circuit board's material also is epoxy and copper layer to the coefficient of thermal expansion difference of resin layer and printed circuit board is little, when the electron part work dispels the heat, can not appear the crack between resin layer and the printed circuit board, thereby has avoided the interference of signal.

2. According to the packaging structure, the metal flange is directly fixed in the printed circuit board, so that the metal flange is not subjected to position deviation, and the consistency of products is improved.

3. According to the packaging structure, the metal flange is filled into the groove, the temperature is raised, the two layers of metal are further fused to form a whole, the metal flange and the metal layer are combined more tightly, and the reliability of subsequent packaging is improved

4. The packaging structure can be used as an intermediate product to be matched with an external circuit board, and can also be directly manufactured into terminal products, such as surface mounted components, radio frequency devices and the like, so that the design freedom degree of the products is greatly improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic diagram of a package structure in the prior art;

FIG. 2 is a schematic structural diagram of a package structure according to an embodiment of the invention;

FIG. 3 is a flow chart of another embodiment of the present invention.

Description of reference numerals:

1. a printed circuit board; 11. a groove; 12. a metal flange; 13. an electronic part; 2. a resin layer; 21. a metal layer; 22. an input electrode; 23. an output electrode; 3. a protective cover.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in fig. 1, fig. 1 shows an electronic component mounting structure in the related art. The electronic part mounting structure comprises a printed circuit board 1, a metal flange 12 and a plurality of electronic parts 13 arranged on the metal flange 12, wherein a groove 11 is arranged on the printed circuit board 1, a metal layer 21 is coated on the groove wall of the groove 11, and the metal flange 12 is limited by the metal layer 21 on the groove wall so as to be fastened in the groove 11.

In the above solution, the electronic component 13 generates heat during operation, and due to the large difference between the thermal expansion coefficients of the metal layer 21 and the printed circuit board 1, cracks may occur, and even the transmission of metal (metal wiring in the printed circuit board) signals of the circuit board on the side wall of the recess 11 may be affected, so that signal delay may occur, and even signal interference may occur seriously. Also, the subsequently grown metal flange does not merge well with the metal layer 21, and thus a problem in terms of reliability may occur.

Example 1:

a packaging structure comprises a printed circuit board 1, a groove 11 is formed in the printed circuit board 1, a metal flange 12 is embedded in the groove 11, a plurality of electronic parts 13 are mounted on the metal flange 12, and the electronic parts 13 are connected through leads according to circuit functions to form a circuit with certain functions. In this embodiment, peripheral circuit components are arranged on the printed circuit board 1, which serve for connection, matching or output/output with respect to the electronics 13 on the metal flange 12. For example, a signal input circuit is provided in the peripheral circuit device to provide an input signal to the electronics 13, and the electronics 13 processes the received signal, such as amplifying, filtering, transforming, etc. For example, a load circuit is mounted in the peripheral circuit device, and the operation is performed based on a voltage signal and a current signal supplied from the electronic component 13. Or a simple connection circuit, which transmits the output signal provided by the electronic part 13 to a circuit arranged outside the printed circuit board 1. In any of the above-mentioned peripheral circuit devices, at least one input electrode 22 and one output electrode 23 are provided on the portion of the printed circuit board 1 adjacent to the metal flange 12, the input electrode 22 and the output electrode 23 are provided on the same side of the printed circuit board 1 as the electronic components 13, the input electrode 22 and the output electrode 23 are respectively connected to the electronic components 13 mounted on the metal flange 12 through leads, and the input electrode 22 and the output electrode 23 are electrically connected to the peripheral circuit of the device. Typically, the two electrodes need to be insulated from the metal flange 12, otherwise a short circuit is easily caused.

In order to solve the problem that the growth of the metal layer can be preserved on the side wall of the groove 11 in the prior art, the difference between the thermal expansion coefficients of the metal layer at the side wall and the printed circuit board 1 is large, the metal layer and the printed circuit board are easy to extrude to generate cracks during working, and the subsequent regrowth of the metal flange 12 is not facilitated, as shown in fig. 2, the side wall of the groove 11 is grown with the resin layer 2, the resin layer 2 covers part of the side wall of the printed circuit board 1, the metal layer 21 is grown on one side of the side wall of the resin layer 2, which is opposite to the groove 11, and the metal flange 12 is fastened in the groove 11 by the metal layer 21 and is subjected to temperature rise and heating treatment at the contact part of the metal layer and the metal flange to be tightly connected. The resin layer 2 can be phenolic resin, urea resin, epoxy resin and the like, and because the side wall of the printed circuit board 1 is directly contacted with the resin material and the printed circuit board 1 is also made of the epoxy resin material and the copper layer, the difference of the thermal expansion coefficients of the two is not large, thereby avoiding signal interference to the maximum extent during work. In addition, when the metal flange 12 is filled into the groove 11, the contact part between the metal flange 12 and the metal layer 21 is subjected to heating up and heating treatment, the heating up and heating treatment has a heating interval, the heating interval is 100-. It should be noted that the thickness of the resin layer 2 is greater than that of the metal layer 21, because the thermal expansion coefficient of metal is much greater than that of resin, if the thickness of the resin layer 2 is greater than that of the metal layer 21, even if the metal layer 21 expands due to heat generated by the operation of the electronic parts, the influence on the printed circuit board 1 can be minimized, thereby maximally preventing possible damage to the electrical signals. In the present embodiment, the thickness of the resin layer 2 is preferably twice the thickness of the metal layer 21. The resin layer 2 may be further etched, for example, the middle upper portion of the resin layer 2 is etched away, so as to form a gap between the metal layer 21 and the printed circuit board 1.

As shown in fig. 2, the printed circuit board 1 is a single plate and has a size that meets the mounting requirements of the metal flange 12 and the electronic component 13. A metal flange 12 is fastened in the recess 11, which metal flange 12 may serve for heat dissipation to the electronic component 13, while in some active device applications the metal flange 12 also serves for grounding. The material of the metal flange 12 depends on the electronic component 13, for example, when the power and heat generation of the electronic component 13 are large, a metal material with good heat dissipation performance may be selected, and when the electronic component 13 is a small power device, a common metal material may be selected to save cost. Generally, the material of the metal flange may be copper, copper tungsten, copper cobalt, or the like. During the preparation, can be earlier a bit bigger than what the notch of recess 11 was seted up, through set up resin layer 2 and metal level 21 on the cell wall of recess 11, adjust grooved size, make the size of notch and metal flange 12 match, then with this metal flange 12 embedding this notch in to installing the electron 13 on metal flange 12, just there is not the problem of offset, improved the stability of technology, make the electron device who makes have fine uniformity.

As shown in fig. 2, a protective cover 3 is added to the printed circuit board 1 in the area adjacent to the metal flange 12 to cover the electronic components 13, thereby protecting the electronic components 13. Preferably, the protective cover 3 is detachably disposed, so that when the electronic component 13 needs to be repaired or replaced or a new electronic component is added to change the operation function, only the protective cover 3 needs to be detached or opened, thereby increasing the flexibility of product design and making the electronic component mounting structure of the present invention have a reusable value. It should be noted that the protective cover 3 in the present invention, unlike the conventional packaging technique, covers the inner space filled with air and not with other insulating media. Air has a relatively low power-saving coefficient, and parasitic capacitance generated by a packaging medium can be reduced in some high-power devices such as radio frequency devices.

Example 2:

a method for manufacturing a package structure, as shown in fig. 3, includes the following steps:

s1, forming a groove 11 in the printed circuit board 1, wherein the size of the groove 11 is larger than that of the metal flange 12, and mechanical drilling or laser drilling can be adopted during grooving;

s2, covering a layer of resin material on the groove wall of the groove 11 to form a resin layer 2, and then carrying out patterning treatment to etch a window required by the lead of the electronic part 13;

s3, covering a layer of metal material on the side wall of the resin layer 2 opposite to the groove 11 to form a metal layer 21, wherein the thickness of the metal layer 21 and the resin layer 2 enables the size of the notch of the groove 11 to be matched with that of the metal flange 12;

in the above step, the thickness of the resin layer 2 is larger than the thickness of the metal layer 21, for example, the thickness of the resin layer 2 is twice or three times the thickness of the metal layer 21. By controlling the thicknesses of the resin layer 2 and the metal layer 21, precise control of the size of the notch of the groove 11 is achieved. Also, after the metal layer is formed, the resin layer 2 may be partially etched, for example, an upper middle portion of the resin layer 2 is etched, so that a gap is formed between the metal layer 21 and the printed circuit board 1.

S4, embedding the metal flange 12 into the groove 11, and tightly connecting the metal flange 12 with the metal layer 21;

in the above steps, the contact portion between the metal flange 12 and the metal layer 21 is subjected to a heating process, wherein the heating process promotes inter-diffusion of particles between the metal flange and the metal layer to form an integral body, and the heating process has a heating region with a temperature of 100 ℃ and 200 ℃.

S5, manufacturing input electrodes 22 and output electrodes 23 distributed on two sides of a metal flange 12 on a printed circuit board 1, and mounting a plurality of electronic parts 13 on the metal flange 12;

in the above steps, two electrode pads are arranged below the printed circuit board 1 at positions corresponding to the input electrode 22 and the output electrode 23, and the two electrode pads are insulated from the metal flange 12; the electronic component 13 is usually a combination of a plurality of electronic components, has a certain electrical function, can serve as a complete circuit, can serve as a certain module in a circuit, and can even serve as a certain electronic component, and when the electronic component 13 is mounted on the metal flange 12, a soldering process with a temperature lower than 250 ℃, such as a low-temperature silver soldering process, should be selected for mounting in consideration of the properties of the printed circuit board 1.

S6, connecting the respective electronic parts 13 through a wire-bonding process, and connecting the input and output terminals of the electronic parts 13 to the input electrode 22 and the output electrode 23 on the printed circuit board 1;

s7, the protective cover 3 is attached above the region where the electronic component 13 is provided. The protective cover 3 has functions of collision prevention, moisture prevention, dust prevention and the like to protect the electronic parts 13 inside from being damaged by the external environment.

In the steps S1 to S7 described in the above embodiment, the manufacturing method is not limited to be performed in the exact order of the steps, and the order of the steps may be changed appropriately.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims

1. A packaging structure comprises a printed circuit board (1), a groove (11) arranged on the printed circuit board (1), a metal flange (12) embedded in the groove (11), and a plurality of electronic parts (13) arranged on the metal flange (12), and is characterized in that a resin layer (2) grows on the side wall of the groove (11), a metal layer (21) grows on one side of the resin layer (2) opposite to the side wall of the groove (11), and the metal layer (21) fastens the metal flange (12) in the groove (11);

wherein the thickness of the resin layer (2) is larger than that of the metal layer (21), and a gap is formed between the metal layer (21) and the printed circuit board (1); and heating the contact part of the metal layer (21) and the metal flange (12) to tightly connect the metal layer and the metal flange.

2. The encapsulation structure according to claim 1, wherein the thickness of the resin layer (2) is twice the thickness of the metal layer (21).

3. The package structure as claimed in claim 1, wherein the temperature-raising heating process has a heating region of 100-200 ℃.

4. The encapsulation structure according to claim 1, characterized in that a protective cover (3) is arranged above the printed circuit board (1) and adjacent to the metal flange (12), wherein the protective cover (3) covers and protects the electronic component (13).

5. The encapsulation structure according to any one of claims 1 to 4, wherein the metal flange (12) is made of copper, copper tungsten or copper molybdenum; or

The resin layer (2) covers a part of a side wall of the printed circuit board (1).

6. A method for manufacturing a package structure according to any one of claims 1 to 5, comprising the steps of:

a groove (11) is formed in the printed circuit board (1), and the size of the groove (11) is larger than that of the metal flange (12);

covering a layer of resin material on the wall of the groove (11) to form a resin layer (2), carrying out patterning treatment, and etching a window required by a lead of the electronic part (13);

covering a layer of metal material on the side wall of the resin layer (2) opposite to the groove (11) to form a metal layer (21), wherein the thickness of the metal layer (21) and the resin layer (2) enables the size of a notch of the groove (11) to be matched with that of the metal flange (12), and the thickness of the resin layer is larger than that of the metal layer;

embedding a metal flange (12) into the groove (11), tightly connecting the metal flange (12) with a metal layer (21), and heating the contact part of the metal layer (21) and the metal flange (12) to tightly connect the metal flange (12);

manufacturing an input electrode (22) and an output electrode (23) which are distributed on two sides of a metal flange (12) on a printed circuit board (1), and installing a plurality of electronic parts (13) on the metal flange (12);

connecting the electronic parts (13) by a lead process, and connecting the input ends and the output ends of the electronic parts (13) to an input electrode (22) and an output electrode (23) on the printed circuit board (1);

a protective cover (3) is arranged above the area provided with the electronic part (13);

after the metal layer (21) is formed, etching is carried out on part of the resin layer (2) so that a gap is formed between the metal layer (21) and the printed circuit board (1).

7. The method as claimed in claim 6, wherein the temperature-raising heating process has a heating region of 100 ℃ to 200 ℃.

8. The manufacturing method of the package structure according to claim 6, wherein when the input electrode (22) and the output electrode (23) are manufactured on the printed circuit board (1) and distributed on two sides of the metal flange (12), two electrode pads are arranged below the printed circuit board (1) at positions corresponding to the input electrode (22) and the output electrode (23), and the two electrode pads are insulated from the metal flange (12).