TWI389610B - Method for manufacturing printed circuit board - Google Patents

Description

Circuit board manufacturing method

The present invention relates to the field of circuit boards, and in particular, to a method of fabricating a circuit board.

Printed circuit boards are widely used due to their high assembly density. For applications on high-density interconnect boards, see 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.

An insulating solder mask is usually required on the surface of the conductive line of the circuit board for shielding a portion of the conductive line that does not need to be in communication with the mounting component or the conductive line, and will need to communicate with other mounting components or conductive lines. Partially exposed. In the prior art, the above-mentioned insulating solder resist layer is usually formed by printing a photosensitive material. After the photosensitive material is printed, it is exposed and developed, so that the portion to be retained remains on the surface of the circuit board conductive line, and the portion that needs to be retained, that is, the portion that needs to communicate with other components or lines from the solder resist layer Exposed. As the size of the board continues to decrease, the distribution of the conductive lines on the surface of the board becomes more and more dense, and the distance between the portion of the line to be exposed and the line to be shielded becomes smaller. During the exposure process, due to the existence of the exposure deviation, in the process of developing, it is easy to expose the portion of the conductive line that needs to be shielded, so that the printed conductive paste such as solder paste and the like are in the process of the subsequent surface mount component. The conductive lines that need to be shielded are connected, and during the subsequent detection process, the conductive lines of the circuit board are short-circuited, resulting in a bad circuit board.

In view of the above, it is necessary to provide a method of manufacturing a circuit board that can detect the deviation of exposure after exposure.

A method of fabricating a circuit board will be described below by way of example.

A circuit board manufacturing method includes the steps of: providing a circuit substrate including a first copper foil layer and an insulating layer; forming a first conductive pattern and a first detecting hole in the first copper foil layer, the first conductive pattern including the first a first cover film, the first cover film is provided with a first opening corresponding to the first pad and a second opening corresponding to the first detecting hole; The film is pressed into the first conductive pattern, so that the first pad is exposed from the first opening, the first detecting hole is exposed from the second opening; the first opening and the second opening are filled with the photosensitive material; and part of the photosensitive in the first opening is removed a material, thereby forming a first via hole exposing the first pad, removing a photosensitive material in a portion of the second opening, thereby forming a second detecting hole; detecting a relative position of the second detecting hole and the first detecting hole, thereby determining Whether the deviation of a via from the first pad satisfies the requirement of the offset tolerance.

Compared with the prior art, the circuit board manufacturing method provided by the technical solution can detect the deviation of exposure and development during the manufacturing process, thereby avoiding the surface of the circuit board from being exposed due to the deviation of exposure and development. If the circuit board is exposed and the deviation does not meet the requirements, the circuit board flows into the subsequent process, causing short circuit during the detection or use of the circuit board, thereby improving the manufacturing yield of the circuit board and reducing the production cost of the circuit board.

The method for fabricating the circuit board provided by the technical solution is further described below with reference to the accompanying drawings and embodiments.

A circuit board manufacturing method provided by the embodiment of the technical solution includes the following steps:

In the first step, referring to FIG. 1, a circuit substrate 100 is provided.

In this embodiment, the circuit substrate 100 is a double-sided adhesive copper foil commonly used in the technical field, that is, the first copper foil layer 110, the second copper foil layer 130, and the first copper foil layer 110 and the second layer. An insulating layer 120 between the copper foil layers 130.

In the second step, referring to FIG. 2 to FIG. 4, the first conductive pattern 111 and the first detecting hole 112 are formed in the first copper foil layer 110 of the circuit substrate 100, and the second detecting layer 112 is formed in the second copper foil layer 130. The conductive pattern 131 and the first light transmission hole 132 corresponding to the first detection hole 112.

In this embodiment, the first conductive pattern 111 is formed in the first copper foil layer 110 by using an image transfer process-etching process, and one or more of the regions of the first copper foil layer 110 except the first conductive pattern 111 are etched. The first detection hole 112. The first conductive pattern 111 includes a first pad 1111 and a first conductive line 1112 for communicating with external or other layer conductive lines. In this embodiment, the first detecting hole 112 is annular and has an outer diameter of 1.0 mm. It can be understood that the outer diameter of the first detecting hole 112 can be set according to the actual circuit board. In addition, the shape of the first detecting hole 112 is not limited to a circular shape, and may be circular inside, and the outside may be designed into other shapes such as a square. In order to facilitate the deviation tolerance of the circuit formed by the marking, a offset bit tolerance mark may be formed in the inner circular copper region 113 of the first detecting hole 112 of the circular ring to facilitate subsequent detection operations.

In addition, four connecting segments in which the copper foil is not etched may be disposed in two mutually perpendicular diameter directions of the first detecting hole 112, and each connecting segment is connected to the outer side of the circular copper region and the first detecting hole 112. Between a copper foil layer 110. When performing the test, it is convenient to observe the direction of the deviation.

The second conductive pattern 131 and the first light-transmissive hole 132 are formed in the second copper foil layer 130 simultaneously with or after the first conductive pattern 111 and the first detecting hole 112 are formed by the image transfer process and the etching process. The second conductive pattern 131 has a second pad 1311 and a second conductive line 1312 for communicating with other elements or additional circuit layers. The first light transmission hole 132 and the first detection hole 112 correspond to each other in a direction perpendicular to the circuit substrate 100. Preferably, the first light transmission hole 132 is disposed coaxially with the first detection hole 112, and the first light transmission hole 132 is disposed. The aperture is larger than the inner diameter of the first detection hole 112. Therefore, the region corresponding to the circuit substrate 100 corresponding to the first detecting hole 112 has only the insulating layer 120, and the strong light can be transmitted from one side of the first light transmitting hole 132 to one side of the first detecting hole 112. In this embodiment, the first light transmission hole 132 has a hole diameter of 1.5 mm. It can be understood that the first light transmission hole 132 is used for transmitting light to the first detection hole 112, and the shape of the opening is not limited to the circular shape in the embodiment, and may be other shapes such as a polygon or an irregular shape.

In the third step, referring to FIG. 5 and FIG. 6, the first cover film 200 and the second cover film 300 are provided.

The first cover film 200 is for covering an area of the first conductive pattern 111 that does not need to communicate with the outside, and the second cover film 300 is for covering an area of the second conductive pattern 131 that does not need to communicate with the outside. In the first embodiment, a first opening 210 corresponding to the first pad 1111 of the first conductive pattern 111 and a second opening 220 corresponding to the first detecting hole 112 are defined in the first cover film 200. A third opening 310 corresponding to the second pad 1311 of the second conductive pattern 131 and a fourth opening 320 corresponding to the first light transmission hole 132 are defined in the second cover film 300. Since the manufacturing precision of the openings of the first cover film 200 and the second cover film 300 is insufficient to ensure that the shape, the size, and the position of the opening of the opening formed by the opening and the conductive line are precisely matched, the first cover film 200 and the second cover film The size of the opening formed in the cover film 300 is slightly larger than the size of the conductive line region, the test pattern, and the light transmission hole corresponding to the external communication. In this embodiment, the second opening 220 and the fourth opening 320 are all circular in shape and have a diameter of 1.5 mm.

In the fourth step, referring to FIG. 7 , the first cover film 200 is pressed onto the first conductive pattern 111 side of the circuit substrate 100 , and the second cover film 300 is pressed onto the second conductive pattern 131 side of the circuit substrate 100 . .

The first cover film 200 is pressed against the first conductive pattern 111 side of the circuit substrate 100 by laminating and then heating at a high temperature, and the second cover film 300 is pressed against the second conductive pattern 131 of the circuit substrate 100. side. The first opening 1111 of the first conductive pattern 111 of the first conductive pattern 111 is exposed, and the first detecting hole 112 is exposed from the second opening 220. The second pad 1311 of the second conductive pattern 131 is exposed from the third opening 310, and a region of the first light-transmissive hole 132 corresponding to the insulating layer 120 is exposed from the fourth opening 320.

In the fifth step, referring to FIG. 8 , the photosensitive material 400 is filled in the first opening 210 and the second opening 220 of the first cover film 200 .

The photosensitive material 400 is filled in the first opening 210 and the second opening 220 of the first cover film 200. The photosensitive material 400 can be formed by printing such that the photosensitive material 400 is in close contact with the exposed regions of the first opening 210 and the second opening 220, so that the uncovered region of the first cover film 200 can be covered. Specifically, the area of the photosensitive material 400 formed at the corresponding position of the first opening 210 is larger than the area of the corresponding first opening 210, so that the photosensitive material 400 formed in the first opening 210 completely covers the first opening 210. The photosensitive material 400 formed in the second opening 220 completely covers the second opening 220. In this embodiment, the photosensitive material 400 in the second opening 220 is circular, and is disposed coaxially with the second opening 220 and has a diameter larger than the diameter of the second opening 220, and has a diameter of 1.7 mm. In this embodiment, the photosensitive material 400 may be a photosensitive ink commonly used in the art, which may be formed of a positive photoresist material or a negative photoresist material.

In the sixth step, referring to FIG. 9, a portion of the photosensitive material 400 in the first opening 210 is removed, thereby forming a first via 411 exposing the first pad 1111, and removing the photosensitive material 400 in the portion of the second opening 220. The second detecting hole 421 exposes the first detecting hole 112 from the second detecting hole 421.

The photosensitive material 400 is exposed and developed by using a negative film having a light-transmitting region corresponding to the shape and position of the first pad 1111 and the first detecting hole 112 of the first conductive pattern 111. The diameter of the light transmitting region of the negative film corresponding to the first detecting hole 112 is larger than the diameter of the inner circular copper portion 113 of the first detecting hole 112. The first detecting hole 411 is formed in the photosensitive material 400 in the first opening 210, and the second detecting hole 421 is formed in the photosensitive material 400 in the second opening 220, and the first detecting hole 112 is exposed from the second detecting hole 421. . The first detecting hole 112 may be partially exposed from the second detecting hole 421 or may be entirely exposed from the second detecting hole 421 to ensure that the light that is directed from the first detecting hole 112 toward the second detecting hole 421 may pass through the first detecting hole. 112 is emitted from the second detection hole 421. In this embodiment, the diameter of the second detecting hole 421 formed is equal to the sum of the diameter of the inner circular copper region 113 and the absolute value of the offset tolerance of twice.

In the seventh step, referring to FIG. 10, the relative position of the first detecting hole 112 and the second detecting hole 421 is detected, thereby determining whether the deviation of exposure and development meets the requirement of the offset tolerance, thereby obtaining a circuit board with a bias tolerance meeting the requirement. 10.

Since the second detecting hole 421 is formed simultaneously with the first via hole 411, the deviation between the second detecting hole 421 and the first detecting hole 112 and the first via hole 411 and the first pad 1111 of the first conductive pattern 111 The deviation between them is equal. Therefore, by detecting the relative positions of the first detecting hole 112 and the second detecting hole 421, it can be determined whether the deviation between the first via 411 and the first pad 1111 of the first conductive pattern 111 satisfies the requirement of the offset tolerance.

In the present embodiment, the relative position of the first detecting hole 112 and the second detecting hole 421 is detected by a visual inspection table device (not shown). The circuit board 10 is placed in parallel on the carrier 20 of the visual inspection table device such that the second cover film 300 of the circuit board 10 is in contact with the carrier 20. Light from the visual inspection station device is transmitted through the stage 20 to the circuit board 10. The light is transmitted to the first detecting hole 112 through the insulating layer 120 through the fourth opening 320 and the first light transmitting hole 132. Since the first detecting hole 112 does not have a copper foil, the light is permeable, and the aperture of the second detecting hole 421 is larger than the diameter of the inner circular copper region 113 of the first detecting hole 112.

Referring to FIG. 11, when the deviation of the exposure development satisfies the requirement of the offset tolerance, a circular transparent region can be observed on one side of the first cover film 200. Referring to FIG. 12, when the deviation of the exposure development does not satisfy the requirement of the offset tolerance, the portion of the first detection hole 112 overlaps with the second detection hole 421, so that a complete circle cannot be observed on one side of the first cover film 200. The light-transmissive area of the ring. Of course, it is also possible to measure the size of different positions of the light-transmitting area by using the detecting device of the visual inspection table device, thereby judging whether the exposure developing deviation satisfies the requirement of the offset tolerance. Thereby, the circuit board 10 with the exposure development deviation meeting the offset tolerance requirement is obtained, so as to avoid the circuit board 10 that cannot meet the offset tolerance requirement flow into the subsequent process or application.

Of course, the circuit board manufacturing method provided by the technical solution can also be used to form the third detecting hole in the second copper foil layer 130 when the second conductive pattern 131 is formed, or to form the first conductive layer when the second conductive pattern 131 is formed. The pattern 111 further forms a second light transmission hole corresponding to the third detection hole in the first copper foil layer 110, and the second cover film 300 further has a sixth opening corresponding to the third detection hole, the first The cover film 200 further has a fifth opening corresponding to the second pad. When the first cover film 200 is pressed against the first conductive pattern 111, the second pad is exposed from the fifth opening, and the second conductive pattern is exposed. When the second cover film is pressed on the 131, the third detecting hole is exposed from the sixth opening, and when the first opening 210 and the second opening 220 are filled with the photosensitive material, the photosensitive material is filled into the fifth opening and the sixth opening. Removing a portion of the photosensitive material in the first opening 210 to remove a portion of the photosensitive material in the fifth opening to form a second via hole in the photosensitive material in the fifth opening, and removing a portion of the photosensitive material in the second opening 220 Part of the sixth opening The material forms a fourth detecting hole in the photosensitive material of the sixth opening, and detects the relative position of the third detecting hole and the fourth detecting hole simultaneously or after detecting the relative position of the second detecting hole and the first detecting hole. And determining whether the deviation between the second via formed on one side of the second cover film and the second pad satisfies the requirement of the offset tolerance.

In addition, the circuit board 100 can also be a single-sided adhesive copper foil. During the manufacturing process, the manufacturing process of the second copper foil layer 130 side is not required. The circuit board manufacturing method provided by the technical solution can also form more layers of circuit boards. Specifically, it is only necessary to press the single-sided adhesive copper foil on the side of the first cover film 200, so that the insulating layer of the single-sided adhesive copper foil is in contact with the first cover film 200, and the single-sided adhesive is pressed on the single side. The copper foil layer of the copper foil forms a conductive pattern and forms a light-transmissive hole in a region corresponding to the first detecting hole, and then conforms to the cover film and forms a photosensitive material, and exposes the photosensitive material to expose the pressed single Whether the surface of the surface adhesive copper foil surface exposure development meets the requirements of the offset tolerance, so that more layers of the circuit board with the exposure deviation satisfying the offset tolerance requirement can be obtained.

The manufacturing method of the circuit board provided by the technical solution can detect the deviation of the exposure and the development during the manufacturing process, thereby avoiding the exposure of the circuit area on the surface of the circuit board which is not exposed due to the deviation of the exposure and the development. The circuit board that causes the deviation does not meet the requirements flows into the subsequent process, and causes a short circuit during the detection or use of the circuit board, thereby improving the manufacturing rate of the circuit board and reducing the production cost of the circuit board.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

10‧‧‧ boards

20‧‧‧Loading station

100‧‧‧ circuit board

110‧‧‧First copper foil layer

111‧‧‧First conductive pattern

1111‧‧‧First pad

1112‧‧‧First conductive line

112‧‧‧First detection hole

113‧‧‧ Copper Zone

120‧‧‧Insulation

130‧‧‧Second copper foil layer

131‧‧‧Second conductive pattern

1311‧‧‧second pad

1312‧‧‧Second conductive line

132‧‧‧First light transmission hole

200‧‧‧First cover film

210‧‧‧ first opening

220‧‧‧second opening

300‧‧‧second cover film

310‧‧‧ third opening

320‧‧‧fourth opening

400‧‧‧Photosensitive materials

411‧‧‧First via

421‧‧‧Second detection hole

FIG. 1 is a schematic diagram of a circuit substrate provided by an embodiment of the present technical solution.

2 is a top plan view of a circuit substrate forming a conductive line provided by an embodiment of the present technical solution.

3 is a bottom view of a circuit substrate forming a conductive line provided by an embodiment of the present technical solution.

Figure 4 is a schematic cross-sectional view of Figure 2 taken along line -V-IV.

FIG. 5 is a schematic diagram of a first cover film provided by an embodiment of the present technical solution.

FIG. 6 is a schematic diagram of a second cover film provided by an embodiment of the present technical solution.

FIG. 7 is a schematic view showing the surface of the conductive circuit provided by the embodiment of the present technical solution after the cover film is pressed.

FIG. 8 is a schematic view showing the formation of a photosensitive material layer provided by an embodiment of the present technical solution.

FIG. 9 is a schematic view of the photosensitive material layer provided by the embodiment of the present technical solution after development.

FIG. 10 is a schematic diagram of detecting the development deviation of the developed circuit board provided by the embodiment of the present technical solution.

FIG. 11 is a positional relationship between a first detecting hole and a second detecting hole in which the post-development deviation provided by the embodiment of the present invention satisfies the deviation tolerance requirement.

FIG. 12 is a positional relationship between a first detecting hole and a second detecting hole which are not satisfied by the deviation tolerance after the developing deviation provided by the embodiment of the present technical solution.

10‧‧‧ boards

20‧‧‧Loading station

1111‧‧‧First pad

112‧‧‧First detection hole

120‧‧‧Insulation

132‧‧‧First light transmission hole

320‧‧‧fourth opening

411‧‧‧First via

421‧‧‧Second detection hole

Claims (10)

A circuit board manufacturing method includes the steps of:
Providing a circuit substrate including a first copper foil layer and an insulating layer;
Forming a first conductive pattern and a first detecting hole in the first copper foil layer, the first conductive pattern comprising a first conductive line and a first pad;
Providing a first cover film, the first cover film is provided with a first opening corresponding to the first pad and a second opening corresponding to the first detecting hole;
Pressing the first cover film to the first conductive pattern such that the first pad is exposed from the first opening, and the first detecting hole is exposed from the second opening;
Filling the first opening and the second opening with a photosensitive material;
Removing a portion of the photosensitive material in the first opening to form a first via hole exposing the first pad, removing the photosensitive material in the portion of the second opening, thereby forming a second detecting hole and making the first detecting hole from the second The detection hole is exposed; and the relative position of the second detection hole and the first detection hole is detected, thereby determining whether the deviation of the first via hole from the first pad satisfies the requirement of the offset tolerance. The method of fabricating a circuit board according to claim 1, wherein the diameter of the first opening is larger than the diameter of the first pad, and the diameter of the second opening is larger than the maximum diameter of the first detecting hole. The method for manufacturing a circuit board according to claim 1, wherein detecting the relative position of the second detecting hole and the first detecting hole comprises the steps of:
Light is incident from one side of the insulating layer such that light is incident on the first detecting hole through the insulating layer and is emitted from the second detecting hole; and observing whether a shape formed by the light emitted from the second detecting hole conforms to a predetermined shape. The method for manufacturing a circuit board according to claim 1, wherein the first detecting hole is an annular opening formed in the first copper foil layer, and the second detecting hole has a hole diameter equal to the first detecting hole. The sum of the inner diameter and the absolute value of the offset tolerance of twice. The method of manufacturing a circuit board according to the fourth aspect of the invention, wherein, when detecting the relative position of the first detecting hole and the second detecting hole, the light is incident from the insulating layer side to the first detecting hole and the second detecting hole. When the light transmission through the first detection hole and the second detection hole is detected to be a circular shape, the deviation between the first via formed by the exposure and the first pad is satisfied. Requirements for offset tolerances. The circuit board manufacturing method of claim 4, wherein the first detecting hole has a circular copper area inside, and the circular copper area is formed with a deviation bit tolerance mark for indicating the The offset tolerance of the first via and the first pad is required. The circuit board manufacturing method of claim 1, wherein the circuit substrate further comprises a second copper foil layer, the insulating layer being located between the first copper foil layer and the second copper foil layer to form Forming a second conductive pattern and a first light-transmissive hole in the second copper foil layer simultaneously or after the first conductive pattern and the first detecting hole, the first light-transmitting hole corresponding to the first detecting hole, the first The light transmission hole is disposed coaxially with the first detection hole, and the diameter of the first light transmission hole is larger than the maximum diameter of the first detection hole. The circuit board manufacturing method of claim 7, wherein the second conductive pattern comprises a second pad, and the circuit board manufacturing method further comprises the steps of:
Providing a second cover film, the second cover film is provided with a third opening corresponding to the second pad and a fourth opening corresponding to the first light transmission hole; and pressing on the second conductive pattern The second cover film is combined such that the second pad is exposed from the third opening, and the exposed region of the first light-transmissive hole is exposed from the fourth opening. The circuit board manufacturing method of claim 8, wherein the fourth opening has a larger diameter than the first light transmission hole, and the third opening has a larger diameter than the second surface. The method for fabricating a circuit board according to the eighth aspect of the invention, wherein the second conductive pattern is further formed in the second copper foil layer when the second conductive pattern is formed, or the first conductive pattern is formed in the second conductive pattern. And forming a second light transmission hole corresponding to the third detection hole in the first copper foil layer, the second cover film further having a fifth opening corresponding to the third detection hole, the first cover film And a sixth opening corresponding to the second pad, the second pad is exposed from the sixth opening when the first cover film is pressed into the first conductive pattern, and the second conductive pattern is pressed on the second conductive pattern When the second cover film is exposed, the third detecting hole is exposed from the fifth opening, and when the first opening and the second opening are filled with the photosensitive material, the photosensitive material is further filled with the fifth opening and the sixth opening, and the part inside the first opening is removed. The photosensitive material further removes a portion of the photosensitive material in the fifth opening to form a second via hole in the photosensitive material in the fifth opening, and removes part of the photosensitive material in the sixth opening when removing the photosensitive material in the second opening. Sense of the sixth opening Forming a fourth detecting hole in the optical material, and detecting the relative position of the second detecting hole and the first detecting hole, or after detecting the relative position of the third detecting hole and the fourth detecting hole, determining the second covering film Whether the deviation of the second via formed on the side and the second pad satisfies the requirement of the offset tolerance.