PCB based on stress design and manufacturing method thereof

Abstract

The invention discloses a stress design-based PCB and a manufacturing method thereof, the stress design-based PCB comprises a substrate and a plurality of PCSs located on the substrate, the substrate is arranged in a rectangular shape and comprises four vertex angles distributed in a crossed manner, the substrate is provided with etching parts in the direction of a connecting line of two adjacent vertex angles, etching areas are formed among the plurality of etching parts, and the PCSs are arranged on the substrate. The etching area is arranged outside a plurality of PCSs in a surrounding mode, the assembling face of each PCS is defined as the front face of the substrate, the face, away from the PCSs, of each PCS is defined as the back face of the substrate, and the etching area comprises a first etching area located on the front face of the substrate and a second etching area located on the back face of the substrate. Rhombic separation lines which are arranged regularly are etched in the center of the first etching area, grid copper which is arranged in an array mode is etched in the center of the second etching area, and the rhombic separation lines correspond to the grid copper. Compared with the prior art, the stress on the two sides of the substrate can be balanced, so that the four corners of the substrate are prevented from tilting.

Description

Technical Field

[0001] The invention relates to a PCB board based on stress design and a manufacturing method thereof, belonging to the technical field of electronic equipment. Background Art

[0002] Since the PCS circuits are not symmetrical, substrates with multiple PCSs are prone to warping due to stress after the normal SMT heat processing process. The original warping problem of substrates with multiple PCBs can be solved by manual material loading and tape pasting, but as module factories tend to automate production lines, labor costs are constantly reduced, and there is no manual tape pasting. The unsolvable substrate warping problem will cause the cutting offset when multiple PCBs are cut into single pieces during the automation process, causing damage to the PCB.

[0003] In view of this, it is indeed necessary to improve the existing PCB board to solve the above problems. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a PCB board based on stress design, which can balance the stress on both sides of the substrate and prevent the four corners of the substrate from warping.

[0005] The technical solution of the present invention is:

[0006] A PCB board based on stress design includes a substrate and a plurality of PCS located on the substrate. The substrate is arranged in a rectangular shape and includes four cross-distributed vertices. In the direction of the line connecting two adjacent vertices, the substrate is provided with an etching portion, and an etching area is formed between the etching portions. The etching area is surrounded by the outside of the plurality of PCSs. The assembly surface of the PCS is defined as the front side of the substrate, and the side away from the PCS is the back side of the substrate. The etching area includes a first etching area located on the front side of the substrate, and a second etching area located on the back side of the substrate. The center of the first etching area is etched with regularly arranged diamond separators, and the center of the second etching area is etched with array-arranged grid copper, and the diamond separators and the grid copper correspond to each other. In this way, the stress arm of the substrate edge solder mask shrinkage on the front side of the substrate is interrupted by the diamond separator, and the stress moment on the front side of the substrate is reduced, so that the solder mask stress of the substrate edge on the front side of the substrate is less than that of the substrate edge on the back side of the substrate; and the design of the grid copper can weaken the strength of the substrate edge on the back side of the substrate, so that the substrate is more easily bent toward the back side.

[0007] As a further improvement of the present invention, in the direction of the line connecting two adjacent vertices, the extension length of the diamond-shaped dividing line is one third of the length of the side of the substrate in this direction.

[0008] As a further improvement of the present invention, in the direction of the line connecting two adjacent vertices, the extension length of the mesh copper is two-thirds of the length of the side of the substrate in this direction.

[0009] As a further improvement of the present invention, a third etching region is formed between two adjacent PCSs on the front side of the substrate, and a separator line connecting two adjacent PCSs is provided in the third etching region. In this way, the stress arm of the substrate when the solder mask shrinks on the front side of the substrate is interrupted by the separator line, thereby reducing the stress moment on the front side of the substrate.

[0010] As a further improvement of the present invention, two partition lines are connected between two adjacent PCSs in the direction of the line connecting two adjacent vertices.

[0011] As a further improvement of the present invention, at least one end of one of the partition lines close to one of the PCSs shrinks toward another partition line.

[0012] The invention also discloses a manufacturing method of a PCB board based on stress design, which is used for manufacturing the above-mentioned PCB board.

[0013] As a further improvement of the present invention, the following steps are included:

[0014] Etching a diamond-shaped partition line at a middle position of the first etching region, wherein an extending direction of the diamond-shaped partition line is the same as an extending direction of the first etching region;

[0015] Etching a mesh copper at a middle position of the second etching region, wherein an extension direction of the mesh copper is the same as an extension direction of the second etching region;

[0016] A separation line connecting two adjacent PCSs is etched in the third etching region.

[0017] As a further improvement of the present invention, etching a separator line connecting two adjacent PCSs in the third etching region includes: etching two separator lines connecting two adjacent PCSs in the third etching region, and at least one end of one of the separator lines close to one of the PCSs shrinks toward the other separator line.

[0018] As a further improvement of the present invention, at most two spacer lines are connected to the same PCS.

[0019] The beneficial technical effect of the present invention is: a PCB board based on stress design of the present invention etches regularly arranged diamond spacers on the first etching area on the front side of the substrate, and etches array-arranged grid copper in the center of the second etching area on the back side of the substrate, so that the diamond spacers and the grid copper correspond to each other, so as to balance the stress on the front and back sides of the substrate to avoid warping of the four corners of the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1The present invention is in accordance with a preferred embodiment of the present invention, a process flow chart of a method for manufacturing a PCB board based on stress design.

[0021] Figure 2 yes Figure 1 Schematic diagram of the local structure after etching diamond-shaped separators in the first etching area.

[0022] Figure 3 yes Figure 1 Schematic diagram of the local structure after etching the grid copper in the second etching area.

[0023] Figure 4 yes Figure 1 Schematic diagram of the local structure after etching the isolation lines in the third etching area.

[0024] Figure 5 It is a test comparison chart. DETAILED DESCRIPTION

[0025] In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples. The following examples are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0026] See also Figures 1 to 4 As shown, the present invention discloses a PCB board based on stress design, the PCB board includes a substrate 1 and a plurality of PCS2 located on the substrate 1, the substrate 1 is arranged in a rectangular shape and includes four cross-distributed vertices, the substrate 1 is provided with an etching portion in the direction of the line connecting two adjacent vertices, an etching area is formed between the plurality of etching portions, the etching area is surrounded by the outside of the plurality of PCS2, the assembly surface of the PCS2 is defined as the front side (i.e., C side) of the substrate 1, the side away from the PCS2 is the back side (i.e., S side) of the substrate 1, the etching area includes a first etching area 12 located on the front side of the substrate 1, and a second etching area 13 located on the back side of the substrate 1, the center of the first etching area 12 is etched with regularly arranged rhombus separators 3, the center of the second etching area 13 is etched with array-arranged grid copper 4, the rhombus separators 3 and the grid copper 4 correspond to each other.

[0027] In this way, the stress arm of the substrate 1 edge on the front side of the substrate 1 is interrupted by the diamond-shaped separator line when the solder mask shrinks, thereby reducing the stress moment on the front side of the substrate 1, so that the solder mask stress of the substrate 1 edge on the front side of the substrate 1 is smaller than that of the substrate 1 edge on the back side of the substrate 1; and the design of the grid copper 4 can weaken the strength of the substrate 1 edge on the back side of the substrate 1, so that the substrate 1 is easier to bend toward the back side.

[0028] Preferably, in the direction of the line connecting two adjacent vertices, the extension length of the diamond-shaped separator line 3 is one third of the side length of the substrate 1 in this direction. The width of the diamond-shaped separator line 3 is 50 um and the length is 2 mm.

[0029] In the direction of the line connecting two adjacent vertices, the extension length of the mesh copper 4 is two-thirds of the side length of the substrate 1 in this direction. The mesh copper 4 is arranged in an array, and the spacing between two adjacent copper sheets is 0.3*0.3mm.

[0030] On the front side of the substrate 1, a third etching area 14 is formed between two adjacent PCS2, and a separator line 5 connecting two adjacent PCS2 is etched in the third etching area 14. In this way, the stress arm of the substrate 1 on the front side of the substrate 1 when the solder mask shrinks is interrupted by the separator line 5, thereby reducing the stress moment on the front side of the substrate 1. In other words, by etching the diamond separator line 3 on the first etching area 12 and the separator line 5 on the third etching area 14, the stress on the front side of the substrate 1 is reduced, and by etching the grid copper 4 on the second etching area 13, the stress on the back side of the substrate 1 is increased. In this way, the balance of stress on both sides is achieved, and the substrate 1 can be prevented from being easily bent due to stress after the normal SMT thermal processing process.

[0031] Preferably, in the direction of the line connecting two adjacent vertices, two separators 5 are connected between two adjacent PCS2, and at least one end of the separator 5 close to one PCS2 shrinks toward the other separator 5. The shrinking distance of the separator 5 is 50 um.

[0032] The present invention also discloses a method for manufacturing a PCB board based on stress design, comprising the following steps:

[0033] Etching a diamond-shaped partition line 3 at a middle position of the first etching region 12, wherein the extending direction of the diamond-shaped partition line 3 is the same as the extending direction of the first etching region;

[0034] Etching a copper mesh 4 at a middle position of the second etching region 13, wherein an extension direction of the copper mesh 4 is the same as an extension direction of the second etching region;

[0035] In the third etching area 14, a separation line 5 connecting two adjacent PCS2 is etched.

[0036] In this embodiment, etching a separator line 5 connecting two adjacent PCS2 in the third etching region includes: etching two separator lines 5 connecting two adjacent PCS2 in the third etching region, and at least one end of one of the separator lines 5 close to one of the PCS2 shrinks toward the other separator line 5.

[0037] Preferably, at most two partition lines 5 are connected to the same PCS2. That is, a plurality of PCS2 are connected in pairs, and there will not be a situation where one PCS2 is connected to two different PCS2s at the same time.

[0038] See also Figure 5 As shown, in this embodiment, various conditions such as the solder mask design on the four sides of the front side of the substrate 1, the copper plating design on the four sides of the back side of the substrate 1, the PCS partition line window opening on the front side of the substrate 1, direct baking (without sandwich baking), sandwich baking, and after the furnace are tested. Among them, direct baking (without sandwich baking) represents the simultaneous action of structural stress and external stress, sandwich baking represents the elimination of part of the structural stress and external stress by external force, and after the furnace represents the release of structural stress. According to the experimental results, all test boards are warped toward the back side of the substrate 1, and it is effective to reversely pull it by balancing the stress. The best effect is achieved when a diamond partition line 3 is adopted on the front side of the substrate 1, a mesh copper 4 is adopted on the back side of the substrate 1, and a window opening process is performed on the partition line 5 on the front side of the substrate 1.

[0039] In summary, a PCB board based on stress design and a manufacturing method thereof of the present invention etches regularly arranged diamond spacers 3 on the first etching area 12 on the front side of the substrate 1, and etches array-arranged grid copper 4 at the center of the second etching area 13 on the back side of the substrate 1, so that the diamond spacers 3 and the grid copper 4 correspond to each other, so as to balance the stress on the front and back sides of the substrate 1, thereby avoiding warping of the four corners of the substrate 1.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A PCB board based on stress design, characterized in that: The invention comprises a substrate and a plurality of PCSs located on the substrate, wherein the substrate is arranged in a rectangular shape and comprises four cross-distributed vertices, wherein the substrate is provided with an etching portion in the direction of a line connecting two adjacent vertices, wherein an etching region is formed between the plurality of etching portions, wherein the etching region is surrounded by the outside of the plurality of PCSs, wherein the assembly surface of the PCS is defined as the front side of the substrate, and the side away from the PCS is defined as the back side of the substrate, wherein the etching region comprises a first etching region located on the front side of the substrate, and a second etching region located on the back side of the substrate, wherein the center of the first etching region is provided with regularly arranged rhombus separators, and the center of the second etching region is provided with array-arranged grid copper, and the rhombus separators and the grid copper correspond to each other.

2. The PCB board based on stress design according to claim 1, characterized in that: In the direction of the line connecting two adjacent vertices, the extending length of the diamond-shaped dividing line is one third of the side length of the substrate in this direction.

3. The PCB board based on stress design according to claim 1, characterized in that: In the direction of the line connecting two adjacent vertices, the extension length of the mesh copper is two-thirds of the length of the side of the substrate in this direction.

4. The PCB board based on stress design according to claim 1, characterized in that: On the front side of the substrate, a third etching region is formed between two adjacent PCSs, and a partition line connecting two adjacent PCSs is provided in the third etching region.

5. The PCB board based on stress design according to claim 4, characterized in that: In the direction of the line connecting two adjacent vertices, two partition lines are connected between two adjacent PCSs.

6. The PCB board based on stress design according to claim 5, characterized in that: At least one end of one of the partition lines close to one of the PCSs is contracted toward the other partition line.

7. A method for manufacturing a PCB board based on stress design, characterized in that: Used to manufacture a PCB board as described in any one of claims 1-6.

8. The method for manufacturing a PCB board based on stress design according to claim 7, characterized in that: The following steps are involved: Etching a diamond-shaped partition line at a middle position of the first etching region, wherein an extending direction of the diamond-shaped partition line is the same as an extending direction of the first etching region; Etching a mesh copper at a middle position of the second etching region, wherein an extension direction of the mesh copper is the same as an extension direction of the second etching region; A separation line connecting two adjacent PCSs is etched in the third etching region.

9. The method for manufacturing a PCB board based on stress design according to claim 8, characterized in that: Etching a separation line connecting two adjacent PCSs in the third etching region includes: etching two separation lines connecting two adjacent PCSs in the third etching region, and at least one end of one of the separation lines close to one of the PCSs shrinks toward the other separation line.

10. The method for manufacturing a PCB board based on stress design according to claim 8, characterized in that: A maximum of two separator lines can be connected to the same PCS.

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