Circuit board capable of reducing pin welding short circuit risk and semiconductor assembly

Abstract

The utility model provides a circuit board capable of reducing pin welding short circuit risk and a semiconductor assembly, and belongs to the technical field of welding, the circuit board is printed with a plurality of bonding pads, the center distance between two adjacent bonding pads is not less than a preset distance threshold; a corresponding first solder mask area is arranged around the periphery of each bonding pad; and the second solder mask area is printed on at least a local area, except for the pads and the first solder mask area, on the circuit board and is positioned among the plurality of pads. The beneficial effects of the utility model are that the second solder mask area is printed on the circuit board, thereby effectively avoiding the problem of welding failure caused by excessive solder paste in the first solder mask area of the pad itself when the solder ball array package is welded, remarkably reducing the risk of short circuit caused by solder paste adhesion between the pins, improving the welding quality, and reducing the production cost. And the welding reliability is enhanced.

Description

Technical Field

[0001] The utility model relates to the technical field of welding, and in particular to a circuit board and a semiconductor component capable of reducing the risk of pin welding short circuit. Background Art

[0002] Circuit board, also known as printed circuit board (PCB), is the basic hardware platform in electronic equipment products, responsible for supporting and connecting various electronic components, including integrated circuit (IC), to build a complete circuit system.

[0003] The production process of circuit boards involves a series of complex and delicate steps, including etching copper foil to form circuit patterns, multi-layer lamination, drilling, and surface printing and silk screen printing. After the basic circuit board is completed, the manufactured circuit board needs to be soldered and assembled with the semiconductor components (or chips) of the integrated circuit.

[0004] In the welding and assembly process of circuit boards and semiconductor components, large-scale ball grid array (BGA) packaging technology is widely used in high-performance electronic devices due to its high pin density and excellent thermal management performance. However, the high pin density of BGA packaging also brings a significant problem: the overflow of solder paste during welding may cause short circuits between pins.

[0005] The solder paste overflow problem mainly stems from the large size and relatively heavy weight of the BGA package. During the soldering process, the gravity of the BGA itself will exert pressure on the pads below it, which may cause the solder paste on the pads to be squeezed out and overflow. Once the overflowed solder paste flows between adjacent pins, it will cause solder bridging, thus causing a short circuit between the pins, seriously affecting the performance and yield of the product.

[0006] At present, the industry has taken a series of preventive measures for the short circuit problem that may occur during BGA welding, mainly including the following aspects:

[0007] (1) Add a solder mask area around the pad to form a physical isolation to prevent solder paste from overflowing. The solder mask area is usually about 4 mils larger than the pad to ensure that the solder paste does not overflow to the adjacent pad within this range.

[0008] (2) Without affecting the soldering of the pad, try to increase the distance between the edges of the pad to leave enough buffer space for solder paste overflow to avoid the phenomenon of solder paste bridging when solder paste overflows, thereby reducing the risk of short circuit.

[0009] (3) Use a stencil to accurately control the amount of solder paste applied during the reflow soldering process. When opening the stencil, a thinner steel plate is used. When brushing solder paste, a thinner solder paste layer will form on the pad. Even if the weight of the BGA package exerts pressure on the pad, the amount of solder paste that overflows will be relatively small due to the thin solder paste layer, thereby reducing the risk of short circuit. However, although this method reduces the risk of solder paste overflow to a certain extent, it is difficult to accurately control in actual operation, and solder paste overflow is still difficult to completely avoid. Utility Model Content

[0010] In order to solve the above technical problems, the utility model provides a circuit board and a semiconductor component which reduce the risk of pin welding short circuit.

[0011] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0012] A circuit board for reducing the risk of pin welding short circuit, the circuit board is printed with:

[0013] A plurality of pads, wherein the center distance between two adjacent pads is not less than a preset distance threshold;

[0014] A corresponding first solder resist area is arranged around the periphery of each of the pads;

[0015] The second solder resist area is printed on at least a partial area of ​​the circuit board except the solder pads and the first solder resist area and is located between the plurality of solder pads.

[0016] Preferably, a first solder resist material is printed on the outer side of the first solder resist area to form the first solder resist area between the pad and the first solder resist material.

[0017] Preferably, the first solder resist material is printed on all areas of the circuit board except the solder pad and the first solder resist area.

[0018] Preferably, a second solder resist material is printed on an outer side of the second solder resist area to form the second solder resist area between the first solder resist area and the second solder resist material.

[0019] Preferably, the second solder resist material is printed on the first solder resist material.

[0020] Preferably, the second solder resist material is white paint.

[0021] Preferably, the printing shape of the second solder resist material is a circle or a square.

[0022] Preferably, the plurality of pads are regularly distributed.

[0023] The utility model also provides a semiconductor component, comprising a packaging substrate, wherein the bottom of the packaging substrate is welded on the circuit board as described above for reducing the risk of pin welding short circuit.

[0024] Preferably, the bottom of the packaging substrate is soldered on the circuit board using a solder ball array.

[0025] The advantages or beneficial effects of the technical solution of the utility model are:

[0026] The utility model prints the second solder resist area on the circuit board, thereby effectively avoiding the welding failure problem caused by excessive solder paste in the first solder resist area of ​​the pad itself when welding the solder ball array package, significantly reducing the risk of short circuit between pins due to solder paste adhesion, improving the welding quality, and enhancing the welding reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a circuit board in a preferred embodiment of the present utility model;

[0028] Figure 2 This is a partial enlarged schematic diagram of a circuit board in a preferred embodiment of the utility model;

[0029] Figure 3 This is a partial enlarged schematic diagram of a circuit board in a preferred embodiment of the present utility model.

[0030] Reference numerals:

[0031] 100, circuit board; 10, solder pad; 20, first solder resist area; 30, second solder resist area; 40, white paint; 50, white paint clearance area. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0033] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0034] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0035] See also Figure 1 , Figure 2 and Figure 3In a preferred embodiment of the utility model, based on the above problems existing in the prior art, a circuit board is provided to reduce the risk of pin welding short circuit. The circuit board 100 is a printed circuit board (PCB) on which are printed:

[0036] A plurality of pads 10, wherein the center distance between two adjacent pads 10 is not less than a preset distance threshold;

[0037] A corresponding first solder resist area 20 is disposed around the periphery of each pad 10;

[0038] The second solder resist area 30 is printed on at least a partial area of ​​the circuit board 100 except the solder pads 10 and the first solder resist area 20 and is located between the plurality of solder pads 10 .

[0039] In this embodiment, each pad 10 is used for welding connection with a pin of a semiconductor component.

[0040] In this embodiment, the center distance between two adjacent pads 10 is greater than or equal to a preset distance threshold. The preset distance threshold is preferably 1 mm to ensure sufficient space to prevent short circuits between pins caused by solder paste overflow. However, in fact, with the miniaturization of chips, there are more and more chips with small pitches, and the pitch can also be set to be less than 1 mm.

[0041] In this embodiment, a corresponding first solder resist area 20 is disposed around the periphery of each pad 10, and its diameter is slightly larger than the diameter of the pad 10. For example, when the diameter of the pad 10 is 0.5 mm, the diameter of the first solder resist area 20 may be 0.6016 mm to 0.7032 mm, that is, 2 mil to 4 mil larger than the pad 10 on one side. The first solder resist area 20 prevents solder paste from overflowing to adjacent pads 10 by physical isolation.

[0042] As a preferred embodiment, the first solder resist material is printed on the outer side of the first solder resist area 20 to form the first solder resist area 20 between the pad 10 and the first solder resist material.

[0043] As a preferred embodiment, the first solder resist material is printed on all areas of the circuit board 100 except the pads 10 and the first solder resist area 20 .

[0044] Furthermore, the first solder resist material preferably includes green solder resist. The green solder resist is printed at a certain distance outside the pad 10 , and the area between the pad 10 and the green solder resist is the first solder resist area 20 .

[0045] The area on the circuit board 100 except the pad 10 and the first solder resist area 20 has a green solder resist.

[0046] As a preferred embodiment, a second solder resist material is printed on the outer side of the second solder resist area 30 to form the second solder resist area 30 between the first solder resist area 20 and the second solder resist material.

[0047] As a preferred embodiment, the second solder resist material is printed on the first solder resist material. The top surface of the second solder resist area 30 is higher than the top surface of the first solder resist area 20. The top surface of the white paint 40 is higher than the top surface of the second solder resist area 30.

[0048] As a preferred embodiment, the second solder resist material is white paint 40 .

[0049] Specifically, white paint 40 is coated on the green solder resist at a certain distance outside the first solder resist area 20 , and the area between the white paint 40 and the first solder resist area 20 is the second solder resist area 30 .

[0050] The area outside the white paint 40 is the white paint clearance area 50, in which no solder resist material such as the white paint 40 is printed. In fact, the second solder resist area 30 is also a white paint clearance area.

[0051] Specifically, green solder resist and white paint 40 are printed on the periphery of each pad 10 on the circuit board 100. The green solder resist is used as a first barrier to block solder paste in the first solder resist area 20; the white paint 40 is used as a second barrier to block solder paste in the second solder resist area 30;

[0052] The white paint 40 has a certain thickness, which can hinder the flow of solder paste to a certain extent, so as to achieve a similar effect to solder resist, thereby reducing the risk of short circuit caused by solder paste overflow during large-scale BGA packaging.

[0053] Furthermore, in addition to using white paint 40 as the solder resist material, other solder resist materials such as green paint may also be used according to actual needs.

[0054] Specifically, considering that in the prior art, when soldering the solder ball array package, the first solder resist area 20 of the pad 10 itself cannot block the solder paste due to excessive solder (such as solder paste), resulting in the solder paste adhesion and short circuit. When the distance between the pad 10 and the edge of the pad 10 has reached the design maximum, such as the pitch of the BGA package is greater than or equal to 1mm and the pad 10 is regularly distributed, the second solder resist area 30 is printed on at least a local area of ​​the circuit board 100 except the pad 10 and the first solder resist area 20, and the second solder resist area 30 is located between adjacent pads 10. Due to the presence of the second solder resist material (white paint 40), the flow of solder paste can be hindered, effectively avoiding the welding failure problem caused by excessive solder paste in the first solder resist area 20 of the pad 10 itself when soldering the solder ball array package, significantly reducing the risk of short circuits caused by solder paste adhesion between pins, improving welding quality, and enhancing welding reliability.

[0055] Pin pitch Pitch refers to the center distance between two adjacent solder balls (tin balls) in the BGA package.

[0056] Specifically, due to the different process capabilities of various board factories, for the sake of safety, the BGA pitch must be greater than or equal to the preset spacing threshold, and the pin distribution must be relatively regular before printing the white paint 40, so as to ensure that the white paint 40 has a sufficient width (such as more than 6 mil) to block the solder paste. This reduces the risk of soldering short circuits during large-scale solder ball array packaging.

[0057] With the development trend of chip miniaturization, the pitch can also be set to less than 1mm.

[0058] As a preferred embodiment, the first preset distance is 6 mil.

[0059] Specifically, the second solder resist area 30 is about 6 mil away from the edge of the pad 10. 1 mil = 1 / 1000 inch = 0.0254 mm. 6 mil is 0.1524 mm.

[0060] Furthermore, the pad 10 , the first solder resist area 20 , the white paint 40 , and the white paint clearance area 50 are arranged in sequence from the inside to the outside.

[0061] As a preferred embodiment, the printing shape of the second solder resist material is a circle or a square.

[0062] Specifically, the printing shape of the second solder resist material includes but is not limited to a circle or a square. Figure 2 and Figure 3 Furthermore, the second solder resist material can also be printed into other regular shapes or irregular shapes.

[0063] Specifically, the second solder resist area 30 is spaced a certain distance from the first solder resist area 20 , that is, the second solder resist area 30 does not cover the first solder resist area 20 , and surrounds the first solder resist area 20 , so that the second solder resist area 30 has a sufficient width to block solder paste.

[0064] like Figure 1 and Figure 2 As shown, the embodiment of the present invention takes the pad 10 having a diameter of 0.5 mm and a pin pitch of 1 mm as an example, but in fact, the specific values ​​can be set according to the actual application scenario, and the present invention does not limit this.

[0065] Specifically, the radius of the first solder resist area 20 is 2 to 3 mils larger than that of the pad 10 .

[0066] The distance between the edge of the second solder resist area 30 and the edge of the pad 10 is 6-8 mil.

[0067] In the process of manufacturing PCBs in a board factory, in the step of printing the silk screen layer, a second layer of white paint 40 can be simultaneously printed between the pads 10 of the circuit board 100 to form a second solder resist area 30 between the first solder resist area 20 and the white paint 40. Therefore, when soldering the BGA package, if the first solder resist area 20 of the pad 10 itself fails due to excessive solder paste, the second layer of white paint 40 can block the solder paste to reduce the short circuit phenomenon caused by the adhesion of solder paste between pins.

[0068] As a preferred embodiment, the plurality of pads 10 are regularly distributed.

[0069] The plurality of pads 10 are distributed in an array.

[0070] Furthermore, the shape of the pad 10 is generally circular, oval, rectangular (including square). In practical applications, the shape of the pad 10 can be selected according to specific application requirements.

[0071] The utility model further provides a semiconductor component, including a packaging substrate, wherein the bottom of the packaging substrate is welded on the circuit board 100 as described above to reduce the risk of pin welding short circuit.

[0072] Furthermore, the packaging substrate is an insulating substrate to ensure the electrical performance and safety of the circuit board 100 .

[0073] As a preferred embodiment, the bottom of the package substrate is soldered on the circuit board 100 using a ball grid array (BGA).

[0074] During the soldering process, if the first solder resist area 20 of the pad 10 itself fails due to excessive solder paste, the white paint 40 will play an additional solder resist role, blocking the solder paste in the second solder resist area 30, reducing the short circuit caused by solder paste adhesion between pins.

[0075] The utility model optimizes the structural design of the circuit board 100, especially adds the second solder resist area 30, thereby effectively reducing the short circuit risk of pin welding and improving the quality and reliability of the product.

[0076] The technical solution of the utility model has been verified on mass-produced boards with good results.

[0077] The advantages or beneficial effects of adopting the above technical solution are: the utility model effectively avoids the welding failure problem caused by excessive solder paste in the first solder resist area of ​​the pad itself when welding the solder ball array package by printing the second solder resist area on the circuit board, significantly reduces the risk of short circuit between pins due to solder paste adhesion, improves welding quality, and enhances welding reliability.

[0078] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of this specification and illustrations should be included in the protection scope of the present invention.

Claims

1. A circuit board with reduced risk of pin welding short circuit, characterized in that: Printed on the circuit board are: A plurality of pads, wherein the center distance between two adjacent pads is not less than a preset distance threshold; A corresponding first solder resist area is arranged around the periphery of each of the pads; The second solder resist area is printed on at least a partial area of ​​the circuit board except the solder pads and the first solder resist area and is located between the plurality of solder pads.

2. The circuit board with reduced risk of pin welding short circuit according to claim 1, characterized in that: A first solder resist material is printed on the outer side of the first solder resist area to form the first solder resist area between the pad and the first solder resist material.

3. The circuit board with reduced risk of pin welding short circuit according to claim 2, characterized in that: The first solder resist material is printed on all areas of the circuit board except the pad and the first solder resist area.

4. The circuit board with reduced risk of pin welding short circuit according to claim 2, characterized in that: A second solder resist material is printed on the outer side of the second solder resist area to form the second solder resist area between the first solder resist area and the second solder resist material.

5. The circuit board with reduced risk of pin welding short circuit according to claim 4, characterized in that: The second solder resist material is printed on the first solder resist material.

6. The circuit board with reduced risk of pin welding short circuit according to claim 4, characterized in that: The second solder resist material is white paint.

7. The circuit board with reduced risk of pin welding short circuit according to claim 4, characterized in that: The printing shape of the second solder resist material is a circle or a square.

8. The circuit board with reduced risk of pin welding short circuit according to claim 1, characterized in that: The plurality of pads are regularly distributed.

9. A semiconductor component, characterized in that: It comprises a packaging substrate, the bottom of which is welded on a circuit board for reducing the risk of pin welding short circuit as claimed in any one of claims 1 to 8.

10. The semiconductor component according to claim 9, characterized in that The bottom of the packaging substrate is soldered on the circuit board using a solder ball array.

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