CN102469703A - How to make a blind hole in a circuit board - Google Patents

Abstract

A method for manufacturing blind holes of a circuit board comprises the following steps: providing an inner-layer circuit board, wherein the inner-layer circuit board comprises a product area and a peripheral area, conductive circuits are formed in the product area, and at least two alignment marks are formed in the peripheral area; pressing a copper-clad substrate on one side of the inner-layer circuit board, which is provided with the conducting circuit and the alignment mark; forming at least one first alignment hole in the inner-layer circuit board laminated with the copper-clad substrate by adopting an X-ray target milling machine, wherein each first alignment hole corresponds to one alignment mark, and at least one alignment mark in at least two alignment marks does not form a corresponding first alignment hole; forming at least one second alignment hole in the copper-clad substrate by taking the at least one first alignment hole as an alignment reference, wherein each second alignment hole corresponds to the alignment mark without the first alignment hole and completely exposes the corresponding alignment mark; and manufacturing and forming a plurality of blind holes penetrating through the copper-clad substrate by taking the alignment mark exposed from the second alignment hole as an alignment reference.

Description

How to make a blind hole in a circuit board

technical field

The invention relates to the field of circuit board production, in particular to a method for producing blind holes in a circuit board.

Background technique

Printed circuit boards have been widely used due to their advantages such as high assembly density. For the application of the circuit board, please refer to the literature Takahashi, A.Ooki, N.Nagai, A.Akahoshi, H.Mukoh, A.Wajima, M.Res.Lab, High density multilayer printed circuit board for HITAC M-880, IEEE Trans. on Components, Packaging, and Manufacturing Technology, 1992, 15(4): 418-425.

In the prior art, the manufacturing method of blind holes in the circuit board usually adopts the following steps, providing an inner layer circuit board with alignment marks; pressing the outer layer copper clad substrate on the inner layer circuit board; usually using X-ray milling The target machine forms an alignment hole at the position corresponding to the alignment mark on the inner layer; then, using the alignment hole as a reference, laser ablation is used to form a blind hole through the copper-clad substrate. However, due to the limitation of the equipment capability of the X-ray target milling machine, the deviation of the alignment hole formed by it is ±20 microns, which leads to the alignment deviation of the blind hole formed by ±20 microns, which will lead to There is a positional deviation between the formed blind hole and the conductive trace on the inner circuit board. As the circuit density of the high-density circuit board increases, such a deviation will lead to poor reliability of the manufactured high-density circuit board and the problem of poor electrical measurement.

Contents of the invention

Therefore, it is necessary to provide a method for manufacturing blind holes on a circuit board, which can effectively improve the alignment accuracy between the formed blind holes and the conductive lines in the inner layer.

A manufacturing method of a circuit board blind hole will be described below with an embodiment.

A method for manufacturing blind holes in a circuit board, comprising the steps of: providing an inner circuit board, the inner circuit board includes a product area and a peripheral area, conductive lines are formed in the product area, and at least two alignment marks are formed in the peripheral area, so The conductive circuit and the at least two alignment marks are located on the same side of the inner circuit board; the side of the inner circuit board formed with the conductive circuit and the alignment mark is pressed to the copper-clad substrate; X- The ray milling target machine forms at least one first alignment hole in the inner circuit board laminated with the copper-clad substrate, and the at least one first alignment hole runs through the copper-clad substrate and the inner circuit board, each Each of the first alignment holes corresponds to an alignment mark, and at least one alignment mark in the at least two alignment marks does not form a corresponding first alignment hole; with the at least one first alignment hole As an alignment reference, at least one second alignment hole is formed in the copper-clad substrate, and each second alignment hole corresponds to an alignment mark not formed with the first alignment hole, and is completely exposed. the corresponding alignment mark; and using the alignment mark exposed from the second alignment hole as an alignment reference, making and forming a plurality of blind holes penetrating through the copper-clad substrate.

Compared with the prior art, the manufacturing method of the blind hole of the circuit board provided by this technical solution, by setting the alignment mark on the inner circuit board, after laminating the copper-clad substrate, only part of the alignment is done by the milling target machine. The corresponding position of the mark forms the first alignment hole, and with the first alignment hole as the alignment reference, a plurality of second alignment holes that can completely expose other alignment marks that have not formed the first alignment hole are formed. In the process of manufacturing the blind hole of the circuit board, the alignment mark exposed from the second alignment hole is used as the alignment reference, so as to ensure the precise alignment of the formed blind hole and the conductive circuit of the inner circuit board.

Description of drawings

Fig. 1 is a schematic plan view of an inner circuit board provided by an embodiment of the technical solution.

FIG. 2 is a schematic cross-sectional view of the inner circuit board in FIG. 1 along the line II-II.

FIG. 3 is a schematic cross-sectional view of the inner layer circuit board in FIG. 2 after the copper-clad substrate is laminated.

FIG. 4 is a schematic plan view of the first alignment hole formed in the inner circuit board laminated with the copper-clad substrate.

Fig. 5 is a schematic cross-sectional view along line V-V of Fig. 4 .

6 is a schematic plan view of the inner layer circuit board laminated with the copper-clad substrate in FIG. 4 after the second alignment holes are formed to expose the corresponding alignment marks.

FIG. 7 is a schematic cross-sectional view along line VII-VII of FIG. 6 .

FIG. 8 is a schematic plan view of a circuit board with blind holes formed.

Description of main component symbols

The first alignment hole 101

Second alignment hole 102

Blind hole 103

Inner circuit board 110

Product area 111

Outer area 112

Substrate 113

Conductive circuit 114

Alignment mark 115

Copper Clad Substrate                              

Insulation layer 121

Copper foil layer 122

Detailed ways

The manufacturing method of the circuit board blind hole provided by the technical solution will be further described below in conjunction with the accompanying drawings and embodiments.

The manufacturing method of the circuit board blind hole provided by the technical solution includes the following steps:

In the first step, please refer to FIG. 1 and FIG. 2 together to provide an inner circuit board 110 .

The inner circuit board 110 is a circuit board with conductive circuits. The inner circuit board 110 can be a single-sided circuit board or a double-sided circuit board, and it can also be a multi-layer circuit board. In this embodiment, the inner circuit board 110 is a single-sided circuit board as an example for illustration. The inner circuit board 110 is substantially rectangular, and includes four product areas 111 and a peripheral area 112 surrounding the product areas 111 and located between adjacent product areas 111 . Each product area 111 corresponds to the shape of the subsequent circuit board product, and the peripheral area 112 is an area that needs to be removed before the subsequent circuit board production. In this embodiment, the inner circuit board 110 includes a substrate 113 , a conductive circuit 114 formed on one surface of the substrate 113 and a plurality of alignment marks 115 . The conductive lines 114 are formed on the product area 111 of the inner circuit board 110 , and a plurality of alignment marks 115 are formed on the peripheral area 112 of the inner circuit board 110 . The number of alignment marks 115 can be set as required, and can be two or more. In this embodiment, the inner circuit board 110 has eight circular alignment marks 115 , each alignment mark 115 has the same size, and each alignment mark 115 has a diameter of 2.0 to 3.5 mm. Every two alignment marks 115 are adjacent to a product area 111 . The alignment marks 115 and the conductive lines 114 are formed by etching at the same time, and the relative positional relationship between the plurality of alignment marks 115 and the conductive lines 114 is fixed.

The second step, please refer to FIG. 3 , is to press-bond the copper clad substrate 120 on the side of the inner layer circuit board 110 provided with the conductive circuit 114 .

In this embodiment, the copper clad substrate 120 is a single-sided copper clad laminate (copper clad laminate), which only needs to include the insulating layer 121 and the copper foil layer 122 . The insulating layer 121 is opposite to the side of the inner layer circuit board 110 provided with the conductive circuit 114 and the alignment mark 115, and the inner layer circuit board 110 and the copper clad substrate 120 are combined into one by thermocompression. overall.

The third step, please refer to Fig. 4 and Fig. 5, is to form at least one alignment mark 115 in the inner layer circuit board 110 with the copper clad substrate 120 by X-ray milling machine. The alignment marks 115 correspond to the first alignment holes 101 one by one, and the first alignment holes 101 pass through the copper clad substrate 120 and the inner circuit board 110 .

The X-ray target milling machine scans the alignment mark 115 of the inner circuit board 110 from one side of the copper foil layer 122 of the copper-clad substrate 120, and passes the position corresponding to the alignment mark 115 scanned by the mechanical drill. The first alignment hole 101 is formed in the form of a hole. In this embodiment, by setting the program of the X-ray target milling machine, the first alignment holes 101 are formed at the positions corresponding to some of the alignment marks 115 among the plurality of alignment marks 115, while other alignment marks 115 correspond to The position does not form the first alignment hole 101 . In this embodiment, the position corresponding to one of the two alignment marks 115 adjacent to each product area 111 forms the first alignment hole 101, while the position corresponding to the other alignment mark 115 does not form the first alignment hole 101. Alignment hole 101. The first alignment hole 101 is a through hole penetrating through the copper clad substrate 120 and the inner circuit board 110 .

In the fourth step, please refer to FIG. 6 and FIG. 7 , using the first alignment hole 101 as an alignment reference, a plurality of second alignment holes 102 are formed in the copper clad substrate 120 by laser ablation, each The second alignment hole 102 corresponds to an alignment mark 115 not formed in the first alignment hole 101 , and fully exposes the corresponding alignment mark 115 .

The size of each second alignment hole 102 corresponds to the size of the alignment mark 115 . In this embodiment, the cross section of each second alignment hole 102 is square, and the side length of the cross section is larger than the diameter of the alignment mark 115 . Specifically, the side length of each second alignment hole 102 is 4.0 mm to 5.5 mm. In this way, even if there is a deviation in the position of the first alignment hole 101 formed by the X-ray milling target machine, since half of the difference between the side length of the second alignment hole 102 and the diameter of the alignment mark 115 is greater than that of the first alignment hole The position of 101 has an absolute value of deviation, therefore, it can be ensured that the formed second alignment hole 102 can completely expose the corresponding alignment mark 115 .

In this embodiment, for each product area 111, the first alignment hole 101 adjacent to it is used as the second alignment hole 102 formed at the corresponding position of another alignment mark 115 adjacent to the product area 111. Alignment reference, a second alignment hole 102 is formed in the copper-clad substrate 120 corresponding to the alignment mark 115 adjacent to each product area 111 without forming the first alignment hole 101, so that it is consistent with each product area An alignment mark 115 adjacent to 111 is completely exposed from its corresponding second alignment hole 102 , so that the deviation caused by expansion and contraction of the circuit board during the pressing process can be further reduced.

It can be understood that the shape of the cross-section of the second alignment hole 102 is not limited to the square provided in this embodiment, and it can also be designed as a circle or a polygon as required. For example, when the cross-section of the second alignment hole 102 is a circular hole, half of the difference between the hole diameter and the diameter of the alignment mark 115 should be greater than the absolute value of the deviation of the X-ray target milling machine.

The fifth step, please refer to FIG. 8 , taking the alignment mark 115 exposed from the second alignment hole 102 as the alignment reference, form a plurality of blind holes 103 penetrating the copper clad substrate 120 in the product area 111 , each blind hole 103 are all corresponding to the conductive lines 114 of the inner circuit board 110 .

In this step, in the formation process of the blind hole 103, the alignment mark 115 provided on the inner circuit board 110 is directly used as the alignment reference, therefore, the blind hole 103 formed by laser ablation can be guaranteed to be consistent with the inner circuit board. The alignment accuracy of the conductive lines 114 in the 110. In this embodiment, when forming the blind hole 103 in each product area 111, the alignment mark 115 adjacent to each product area 111 and exposed from the second alignment hole 102 can be used as an alignment reference, so , which can further reduce the deviation caused by the expansion and contraction of the circuit board during the pressing process.

The manufacturing method of the circuit board blind hole provided by this technical solution is to set the alignment mark 115 on the inner circuit board 110, and after the copper-clad substrate 120 is laminated, only part of the alignment mark 115 is made by an X-ray milling target machine. Form the first alignment hole 101 at the corresponding position, and use the first alignment hole 101 as the alignment reference to form a plurality of second alignment holes that can completely expose other alignment marks 115 that do not form the first alignment hole 101 102 , during the manufacturing process of the circuit board blind hole 103 , the exposed alignment mark 115 is used as an alignment reference, thereby ensuring precise alignment between the formed blind hole 103 and the conductive circuit of the inner circuit board 110 .

It can be understood that those skilled in the art can make various other corresponding changes and modifications according to the technical concept of the present invention, and all these changes and modifications should belong to the protection scope of the claims of the present invention.

Claims (10)

1. A method for making a circuit board blind hole, comprising steps: An inner layer circuit board is provided, the inner layer circuit board includes a product area and a peripheral area, a conductive circuit is formed in the product area, at least two alignment marks are formed in the peripheral area, the conductive circuit and the at least The two alignment marks are located on the same side of the inner circuit board; Pressing the copper-clad substrate on the side of the inner circuit board on which the conductive lines and alignment marks are formed; Using an X-ray milling target machine to form at least one first alignment hole in the inner layer circuit board laminated with the copper-clad substrate, the at least one first alignment hole runs through the copper-clad substrate and the inner layer On a circuit board, each of the first alignment holes corresponds to an alignment mark, and the position corresponding to at least one of the at least two alignment marks does not form a first alignment hole; Using the at least one first alignment hole as an alignment reference, at least one second alignment hole is formed in the copper-clad substrate, and each second alignment hole is connected to one without the first alignment hole. correspond to and fully expose the corresponding registration marks; and Taking the alignment mark exposed from the second alignment hole as an alignment reference, a plurality of blind holes penetrating through the copper-clad substrate are formed. 2 . The method for manufacturing blind holes on a circuit board according to claim 1 , wherein the alignment mark and the conductive circuit are formed by etching copper foil at the same time. 3 . 3. The method for making a blind hole in a circuit board according to claim 1, wherein the shape of the alignment mark is circular, the shape of the cross section of the second alignment hole is a square, and the shape of the second alignment hole is square. The side lengths of the cross sections of the two alignment holes are larger than the diameter of the alignment marks. 4. The method for making a blind hole in a circuit board according to claim 3, wherein half of the length difference between the side length of the cross section of the second alignment hole and the diameter of the alignment mark is greater than the The absolute value of the deviation of the X-ray target milling machine. 5. The method for making a blind hole in a circuit board according to claim 1, wherein the alignment mark is circular in shape, the cross-section of the second alignment hole is circular in shape, and the alignment mark is circular in shape. The diameter of the cross section of the second alignment hole is larger than the diameter of the alignment mark. 6. The method for making a blind hole in a circuit board according to claim 5, wherein half of the length difference between the diameter of the second alignment hole and the diameter of the alignment mark is greater than that of the X-ray milling machine. The absolute value of the deviation of the target machine. 7. The method for making a blind hole in a circuit board according to claim 1, wherein the inner layer circuit board includes a plurality of product areas, the peripheral area surrounds the product area, and each product area is connected to at least Two corresponding alignment marks are adjacent. 8. The method for making a blind hole in a circuit board according to claim 7, wherein in the step of forming the first alignment hole, the position corresponding to one of the alignment marks adjacent to each product area A first alignment hole is formed. 9. The method for making blind holes in a circuit board according to claim 8, wherein, in the step of forming the second alignment holes, the pairs adjacent to each product area that do not correspond to form the first alignment holes The positions corresponding to the bit marks form the second alignment holes. 10. The method for making blind holes in a circuit board according to claim 9, wherein when forming the second alignment hole, the first alignment hole adjacent to the same product area as the second alignment hole is used. The hole is used as an alignment reference. When forming a blind hole, the adjacent alignment mark exposed from the second alignment hole corresponding to each product area is used as an alignment reference.

Images