CN108834336B - Manufacturing method of PCB - Google Patents

Abstract

The invention relates to the technical field of circuit board production, and discloses a manufacturing method of a PCB, which comprises the following steps: s1, providing a first substrate provided with a first through groove, a second substrate, a third substrate provided with a second through groove and a fourth substrate, and manufacturing a circuit pattern on the surface of the fourth substrate; s2, sequentially laminating the first substrate, the second substrate, the third substrate and the fourth substrate, and pressing to obtain a multilayer board; s3, carrying out copper deposition and electroplating treatment on the multilayer board to metalize the groove wall and the groove bottom of the first groove; s4, milling the bottom of the first groove at the top of the second through groove to form a second groove; and S5, opening a third through groove at the bottom of the second groove. The manufacturing method of the PCB realizes the mounting of the special-shaped component and various components with different sizes, reduces the occupied space of the PCB, manufactures the circuit pattern at the bottom of the stepped groove and is beneficial to further miniaturization of the PCB.

Description

A kind of manufacturing method of PCB

technical field

The invention relates to the technical field of circuit board production, in particular to a method for manufacturing a PCB.

Background technique

Printed circuit board (PCB for short) is the provider of electrical connection for electronic components. Before the appearance of printed circuit boards, the interconnection between electronic components relied on the direct connection of wires to form a complete circuit. In contemporary times, circuit panels only exist as effective experimental tools, and printed circuit boards have occupied an absolute dominant position in the electronics industry.

In order to meet the high-density mounting or crimping requirements of printed circuit boards, multi-layer printed circuit boards are designed to open stepped grooves to reduce the assembly volume. The current stepped groove design mostly shows first-order metallization or non-metallization Step slots are used in microwave radio frequency products or embedded power amplifier components in step positions. The existing design has the following shortcomings:

1) The shape of the first-order stepped groove is single, and it is impossible to mount components with special-shaped structures;

2) A single metallized or non-metallized stepped groove cannot meet the special assembly requirements of components at the same time, or integrate other more power amplifier devices.

Therefore, a PCB manufacturing method is needed to solve the above problems by manufacturing stepped grooves with multi-layer steps.

Contents of the invention

The purpose of the present invention is to provide a method for manufacturing PCB, to form a stepped groove with multi-layer steps on the PCB, to realize the mounting of special-shaped components and components of different sizes, and to reduce the occupied space of the PCB. The circuit pattern is made at the bottom of the groove, which is conducive to the further miniaturization of the PCB.

For reaching this purpose, the present invention adopts following technical scheme:

A method for manufacturing a PCB, comprising the steps of:

S1. Provide a first substrate with a first through groove, a second substrate, a third substrate with a second through groove, and a fourth substrate, and make a circuit pattern on the surface of the fourth substrate;

S2, stacking the first substrate, the second substrate, the third substrate and the fourth substrate in sequence, so that the first through groove and the second substrate form a first groove, and the circuit on the fourth substrate The pattern is located at the bottom of the second through-groove of the third substrate, and the second through-groove of the third substrate is located under the first groove, and is laminated to form a multi-layer board;

S3, performing copper sinking and electroplating treatment on the multi-layer board, so as to metallize the groove wall and the groove bottom of the first groove;

S4. Milling off the bottom of the first groove at the top of the second through groove to form a second groove;

S5. Opening a third through groove at the bottom of the second groove.

Specifically, first of all, three-level stepped grooves are set on the laminated multi-layer board, which can realize the mounting of components with special-shaped structures, and can also realize the assembly of components with different structures and mount them on the PCB. The components or assembled components are placed in the stepped groove, which not only makes full use of the space of the stepped groove, but also saves the installation space of the PCB and greatly reduces the assembly volume of the PCB; secondly, the groove wall of the first groove is made of metal It is easy to mount components, which is beneficial to signal shielding of components, metallizes the bottom of the first groove, and improves the heat dissipation efficiency of components; finally, the bottom of the second groove is provided with a circuit pattern , which is conducive to the further miniaturization of PCB.

As a preferred technical solution, the horizontal cross-sectional projection of the first groove covers the horizontal cross-sectional projection of the second groove.

As a preferred technical solution, between step S2 and step S3 includes: step S21, processing a via hole at the bottom of the first groove, and the via hole does not pass through the second through groove.

As a preferred technical solution, in step S3, copper sinking and electroplating are performed on the multi-layer board to metallize the walls of the via holes.

Specifically, a via hole is processed at the bottom of the first groove, and the hole wall of the via hole is metallized by sinking copper and electroplating, and the hole wall metallized via hole is used to connect the inner circuit pattern of the multilayer board.

As a preferred technical solution, the horizontal cross-sectional projection of the second groove covers the horizontal cross-sectional projection of the third through groove.

Specifically, the horizontal cross-sectional areas of the first groove, the second groove and the third through groove decrease in order to form a "T"-shaped stepped groove, which is suitable for installing special-shaped components.

As a preferred technical solution, in step S2, a prepreg with a through groove is stacked between the second substrate and the first substrate, and the horizontal cross-sectional profile of the through groove on the prepreg is larger than that of the first substrate. Horizontal cross-sectional profile of the first through-slot on the substrate.

As a preferred technical solution, in step S2, a prepreg with a through groove is stacked between the third substrate and the second substrate, and the horizontal cross-sectional profile of the through groove on the prepreg is larger than that of the third substrate Horizontal cross-sectional profile of the upper second slot.

As a preferred technical solution, in step S2, a prepreg with a through groove is stacked between the third substrate and the fourth substrate, and the horizontal cross-sectional profile of the through groove on the prepreg is larger than that of the third substrate Horizontal cross-sectional profile of the upper second slot.

Specifically, the prepreg is used to bond the third substrate to the second substrate and the third substrate to the fourth substrate, so that the through groove on the prepreg is slightly larger than the second through groove on the third substrate, so as to avoid glue flow when pressing the prepreg. into the second channel.

Specifically, the prepreg can be a single prepreg or multiple prepregs, and the prepregs are stacked according to the actual lamination situation.

As a preferred technical solution, the first substrate, the second substrate, the third substrate and the fourth substrate are a core board and/or a sub-board formed by laminating a plurality of core boards.

Beneficial effects of the present invention: firstly, three-level stepped grooves are set on the laminated multi-layer board, which can realize the mounting of components with special-shaped structures, and can also realize the assembly and mounting of components with different structures on the PCB , The components with special-shaped structure or assembled components are placed in the stepped groove, which not only makes full use of the space of the stepped groove, but also saves the installation space of the PCB, greatly reducing the assembly volume of the PCB; secondly, making the first groove The metallization of the groove wall facilitates the mounting of components, which is conducive to signal shielding of components, metallizes the groove bottom of the first groove, and improves the heat dissipation efficiency of components; finally, the groove bottom of the second groove is designed There are circuit patterns, which is conducive to the further miniaturization of PCB.

Description of drawings

Fig. 1 is the flow chart of the manufacturing method of PCB described in the embodiment of the present invention;

Fig. 2 is a schematic diagram of the stacked state of the first substrate, the second substrate, the third substrate and the fourth substrate described in the embodiment of the present invention;

Fig. 3 is a schematic diagram of the state after the copper plating of the multilayer board described in the embodiment of the present invention;

Fig. 4 is a schematic diagram of the state of forming stepped grooves on a multi-layer board according to an embodiment of the present invention.

In the picture:

1. The fourth substrate; 2. The third substrate; 3. The second substrate; 4. The first substrate; 5. The first groove; 6. The second groove; 7. The third through groove; 8. Copper layer; 9. Second slot; 10. First slot; 11. Prepreg.

Detailed ways

The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation methods. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, only the parts related to the present invention are shown in the drawings but not all of them.

As shown in Figure 1, a method for manufacturing a PCB includes the following steps:

Step 1. Provide the first substrate 4 with the first through groove 10, the second substrate 3, the third substrate 2 with the second through groove 9, and the fourth substrate 1, and fabricate on the surface of the fourth substrate 1. Line graphics.

The first substrate 4, the second substrate 3, the third substrate 2 and the fourth substrate 1 are respectively a core board or a sub-board formed by laminating multiple core boards, and the core board and/or The sub-boards are combined to obtain the required number of copper layers; and the combination of these core boards and/or sub-boards can be pressed into a laminated board in this step, or can be laminated and pressed together in a subsequent step. The first through groove 10 on the first substrate 4 and the second through groove 9 on the third substrate 2 can be processed by a milling machine.

In this embodiment, the horizontal cross-sectional projection of the second through-groove 9 on the third substrate 2 is located within the range of the horizontal cross-sectional projection of the first through-groove 10 on the first substrate 4 . In addition, circuit patterns are formed on the upper surface of the fourth substrate 1 , but not limited to the circuit patterns on the upper surface of the fourth substrate 1 , circuit patterns can also be formed on the lower surface of the fourth substrate 1 .

In this embodiment, one first through-slot 10 is opened on the first substrate 4 . In addition, multiple first through-slots 10 may also be opened on the first substrate 4 according to the number of mounted components.

Step 2, sequentially stack the first substrate 4, the second substrate 3, the third substrate 2 and the fourth substrate 1, as shown in Figure 2, make the first through groove 10 on the first substrate 4 and the second substrate 3 form the first groove 5, the circuit pattern on the fourth substrate 1 is located at the bottom of the second through groove 9 of the third substrate 2, and the second through groove 9 of the third substrate 2 is located at the first Below the groove 5, it is laminated to form a multi-layer board. Wherein, the first through groove 10 and the second through groove 9 can optionally be filled with resist blocks to prevent the prepreg from flowing into the groove during pressing.

Specifically, the third substrate 2 is provided with a second through groove 9, and when the first substrate 4, the second substrate 3, the third substrate 2 and the fourth substrate 1 are stacked together, the second through groove 9 The horizontal cross-sectional area is smaller than the horizontal cross-sectional area of the first groove 5 .

Specifically, a prepreg 11 with a through-groove is stacked between the second substrate 3 and the first substrate 4, and the horizontal cross-sectional profile of the through-groove on the prepreg 11 is larger than that on the first substrate 4. The horizontal cross-sectional profile of the first through groove 10.

A prepreg 11 with a through-groove is stacked between the third substrate 2 and the second substrate 3 , and the horizontal cross-sectional profile of the through-groove on the prepreg 11 is larger than the horizontal cross-sectional profile of the second through-groove 9 on the third substrate 2 .

A prepreg 11 with a through-groove is stacked between the third substrate 2 and the fourth substrate 1 , and the horizontal cross-sectional profile of the through-groove on the prepreg 11 is larger than the horizontal cross-sectional profile of the second through-groove 9 on the third substrate 2 . The outlines described above have the same shape.

The above-mentioned prepreg 11 can be one prepreg 11 or a plurality of prepregs 11 stacked together, and the prepregs 11 are stacked according to the actual lamination situation.

Step 3, machining a via hole at the bottom of the first groove 5 , and the via hole does not pass through the second through slot 9 .

As shown in FIG. 3 , in this embodiment, a via hole is processed at the bottom of the first groove 5 , and the via hole is processed by mechanical drilling. In addition, the number of processed via holes is not limited to one, but can also be multiple.

Step 4: Carry out copper sinking and electroplating treatment on the multi-layer board, metallize the groove wall and groove bottom of the first groove 5, and metallize the hole walls of the via holes to form hole wall copper.

As shown in Figure 3, metallization of the groove wall and groove bottom of the first groove 5 forms a connected copper layer 8 through copper sinking and electroplating, and the metallization of the groove wall realizes the placement of components, which is beneficial to Signal shielding makes the bottom of the first groove 5 metallized, which improves the heat dissipation efficiency of components.

Metallize the hole wall of the via hole by sinking copper and electroplating, and the metallized via hole is used to connect the inner circuit pattern of the multilayer board. Described copper layer 8 is communicated with hole wall copper, also can make circuit pattern on the copper layer 8 at the bottom of the groove 5 of the first groove, and the circuit pattern on the bottom of the groove 5 of the first groove and each on the multilayer board Layer circuit graphics to achieve electrical connectivity.

Step 5, milling off the bottom of the first groove 5 at the top of the second through groove 9 to form the second groove 6 .

Specifically, as shown in Figure 4, the horizontal section projection of the second groove 6 is located within the horizontal section projection range of the first groove 5, the groove wall of the second groove 6 is non-metallized, and the bottom of the groove is With a circuit pattern, the components are placed in the second groove 6 and connected with the circuit pattern, which is beneficial to the further miniaturization of the PCB.

Before milling off the bottom of the first groove 5 at the top of the second through groove 9, the multi-layer board is subjected to copper sinking and electroplating, which is beneficial to protect the circuit pattern at the bottom of the second groove 6, and can also ensure The groove wall of the second groove 6 is non-metallized, which improves the efficiency of processing the stepped groove.

In this embodiment, one second groove 6 is provided below the first groove 5 , and multiple second grooves 6 may also be provided below the first groove 5 .

Step 6, opening a third through groove 7 at the bottom of the second groove 6 .

Specifically, as shown in FIG. 4, the horizontal section projection of the third through groove 7 is located within the range of the horizontal section projection of the second groove 6, and the groove wall of the third through groove 7 is non-metallized, which can realize Submerged assembly of components greatly reduces the assembly volume of PCB.

In this embodiment, one third through-slot 7 is provided below the second groove 6 , and multiple third through-slots 7 may also be provided below the second groove 6 .

In this embodiment, the horizontal cross-sectional areas of the first groove 5, the second groove 6 and the third through groove 7 are successively reduced to form a "T"-shaped stepped groove, which is suitable for installing special-shaped components, groove walls and grooves The metallization or non-metallization of the bottom not only improves the power amplifier efficiency of the components, but also improves the transmission speed of the signal and reduces the loss of the signal. In addition, the stepped grooves on the PCB are not limited to three-level stepped grooves, but can also be more than three-level stepped grooves.

The step grooves opened on the PCB in this embodiment can realize the mounting of components with special-shaped structures and components of various sizes, reduce the space occupied by the PCB, and improve the reliability of the components installed in the step grooves. The speed of signal transmission can reduce the loss of signal, and the manufacturing method of this PCB is simple and feasible, and it is mass-producible.

Apparently, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (9)

1. A manufacturing method of PCB, is characterized in that, comprises the following steps: S1. Provide a first substrate with a first through groove, a second substrate, a third substrate with a second through groove, and a fourth substrate, and make a circuit pattern on the surface of the fourth substrate; S2, stacking the first substrate, the second substrate, the third substrate and the fourth substrate in sequence, so that the first through groove and the second substrate form a first groove, and the circuit on the fourth substrate The pattern is located at the bottom of the second through-groove of the third substrate, and the second through-groove of the third substrate is located under the first groove, and is laminated to form a multi-layer board; S3, performing copper sinking and electroplating treatment on the multi-layer board, so as to metallize the groove wall and the groove bottom of the first groove; S4. Milling off the bottom of the first groove at the top of the second through groove to form a second groove; S5. Opening a third through groove at the bottom of the second groove. 2 . The PCB manufacturing method according to claim 1 , wherein the horizontal cross-sectional projection of the first groove covers the horizontal cross-sectional projection of the second groove. 3 . 3. The manufacturing method of PCB according to claim 2, characterized in that, between step S2 and step S3, it comprises: step S21, processing a via hole at the bottom of the first groove, and the via hole does not through the second slot. 4 . The PCB manufacturing method according to claim 3 , wherein, in step S3 , copper sinking and electroplating are performed on the multi-layer board to metallize the walls of the via holes. 5 . 5 . The manufacturing method of PCB according to claim 1 , wherein the horizontal cross-sectional projection of the second groove covers the horizontal cross-sectional projection of the third through groove. 6. The manufacturing method of PCB according to claim 1, characterized in that, in step S2, a prepreg with a through groove is stacked between the second substrate and the first substrate, and the prepreg The horizontal cross-sectional profile of the through groove on the upper substrate is larger than the horizontal cross-sectional profile of the first through groove on the first substrate. 7. The manufacturing method of PCB according to claim 1, characterized in that, in step S2, a prepreg with a through groove is stacked between the third substrate and the second substrate, and the prepreg The horizontal cross-sectional profile of the upper through groove is larger than the horizontal cross-sectional profile of the second through groove on the third substrate. 8. The manufacturing method of PCB according to claim 1, characterized in that, in step S2, a prepreg with a through groove is stacked between the third substrate and the fourth substrate, and the prepreg The horizontal cross-sectional profile of the upper through groove is larger than the horizontal cross-sectional profile of the second through groove on the third substrate. 9. The manufacturing method of PCB according to claim 1, characterized in that, the first substrate, the second substrate, the third substrate and the fourth substrate are core boards or sub-substrates formed by laminating multiple core boards. plate.