Sidewall Selective Light-Resistant Mold, Method for Fabricating Pattern of Step Groove and PCB

Abstract

The present invention relates to the technical field of PCBs, and discloses a sidewall selective light-blocking mold, a method for fabricating a pattern of a stepped groove, and a PCB. The sidewall selective light-blocking mold is applied to a groove body to achieve selective exposure of a first photosensitive film covering the sidewall of the groove body, and includes: a first light-transmitting body, which is matched with the structure of the groove body, and a light-blocking pattern is provided on its side surface, and the light-blocking pattern corresponds to the quasi-non-exposed area of the first photosensitive film; a light reflection unit, which is fixedly arranged in the first light-transmitting body and is used for reflecting the exposure light source incident from the top surface of the first light-transmitting body, so that the exposure light source exits through the area not covered by the light-blocking pattern on the side surface of the first light-transmitting body to the quasi-exposed area of the first photosensitive film. Based on this sidewall selective light-blocking mold, subsequent sidewall metal patterns that meet the requirements of various shape designs can be fabricated according to conventional processes such as development and etching, which not only has a simple process but also has high fabrication accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of PCB (Printed Circuit Boards), and particularly relates to a sidewall selective light-blocking mold, a method for fabricating a stepped groove pattern, and a PCB. Background Art

[0002] As Figure 1 shown, the current mainstream method for fabricating the sidewall pattern of a PCB stepped groove is to use an irregular convex drill or milling cutter to perform controlled drilling or controlled-depth milling. The fabricated sidewall metal pattern can only be a rectangular or square pattern, the pattern is too single, and the requirements for the depth control accuracy and position accuracy are very high, and the dimensional accuracy of the pattern is poor. Summary of the Invention

[0003] The purpose of the present invention is to provide a sidewall selective light-blocking mold, a method for fabricating a stepped groove pattern, and a PCB, so as to solve the problems of low fabrication accuracy and single pattern of the stepped groove sidewall pattern in the prior art.

[0004] To achieve this purpose, the present invention adopts the following technical solutions:

[0005] A sidewall selective light-blocking mold is applied to a groove body to realize selective exposure of a first photosensitive film covering the sidewall of the groove body. The sidewall selective light-blocking mold includes:

[0006] A first light-transmitting body, which is matched with the structure of the groove body, and a light-blocking pattern is provided on its side surface. The light-blocking pattern corresponds to the non-exposure area of the first photosensitive film.

[0007] A light reflection unit is fixedly arranged in the first light-transmitting body and is used to reflect the exposure light source incident from the top surface of the first light-transmitting body, so that the exposure light source exits from the area of the side surface of the first light-transmitting body that is not covered by the light-blocking pattern to the exposure area of the first photosensitive film.

[0008] Optionally, an installation cavity is provided in the first light-transmitting body. The installation cavity is a conical structure, a frustum of a cone structure, a pyramid structure, or a frustum of a pyramid structure, and the included angle between the side wall of the installation cavity and the bottom surface of the first light-transmitting body is within a preset included angle range. The central value of the preset included angle range is 45 degrees;

[0009] The light reflection unit includes a reflecting mirror, and the reflecting mirror is arranged around the side wall of the installation cavity.

[0010] Optionally, the installation cavity is in a triangular prism structure, the intersection line of the first side face and the second side face of the triangular prism structure is the midline of the top face of the first light-transmitting body, and the angles between the first side face and the top face of the first light-transmitting body, and between the second side face and the top face of the first light-transmitting body are both within a preset angle range, and the central value of the preset angle range is 45 degrees;

[0011] The light reflection unit includes a reflector, and the reflector is arranged on the first side face and the second side face of the installation cavity.

[0012] A method for manufacturing a pattern of a stepped groove includes the steps of:

[0013] Providing a PCB having a groove body and a sidewall selective light-blocking mold as described in any one of the above; a first metal layer is coated on the sidewall of the groove body, and a first photosensitive film is coated on the surface of the first metal layer, and the proposed exposure area of the first photosensitive film corresponds to the proposed sidewall metal pattern to be manufactured;

[0014] Placing the sidewall selective light-blocking mold into the groove body, and irradiating an exposure light source with the top face of the first light-transmitting body as the incident surface, so that after the exposure light source is reflected by the light reflection unit, it exits through the area of the side face of the first light-transmitting body that is not covered with the light-blocking pattern and reaches the proposed exposure area of the first photosensitive film, realizing the exposure of the proposed exposure area of the first photosensitive film;

[0015] After exposure, development, etching, and removal of the first photosensitive film are sequentially performed to obtain the corresponding sidewall metal pattern.

[0016] Optionally, the method for manufacturing the first photosensitive film on the surface of the first metal layer includes:

[0017] Pouring a liquid photosensitive material into the groove body, and the photosensitive material is a wet film or ink;

[0018] Pressing a film layer manufacturing mold into the groove body so that the photosensitive material flows to cover the entire surface of the first metal layer on the sidewall of the groove body;

[0019] Baking the photosensitive material covering the surface of the first metal layer at a high temperature until the photosensitive material is cured to form the first photosensitive film;

[0020] Taking out the film layer manufacturing mold.

[0021] Optionally, the film layer manufacturing mold includes: a mold body with a material receiving cavity provided therein;

[0022] The outer dimension of the mold body is smaller than the inner dimension of the groove body by a preset film layer thickness value on each side, and a flow channel communicating the inside and outside of the receiving cavity is provided at the top end of the sidewall of the mold body.

[0023] Optionally, the angle between the direction in which the flow channel points from its inlet end to its outlet end and the corresponding side wall is an acute angle.

[0024] Optionally, a positioning mechanism is formed by extending the top surface of the mold body outward along its four peripheral edges.

[0025] Optionally, the bottom surface of the groove body is covered with a second metal layer, and the surface of the second metal layer is covered with a second photosensitive film;

[0026] The method for manufacturing the pattern further includes:

[0027] Manufacturing a bottom-selective light-blocking mold adapted to the groove body, the bottom-selective light-blocking mold including a second light-transmitting body; in the region of the second light-transmitting body corresponding to the quasi-non-exposed region of the second photosensitive film, it is hollowed out and injected with a light-blocking substance along the thickness direction;

[0028] Placing the bottom-selective light-blocking mold into the groove body, and irradiating an exposure light source with the top surface of the second light-transmitting body as the incident surface, so that the exposure light source exits through the region of the second light-transmitting body where the light-blocking substance is not injected to the quasi-exposed region of the second photosensitive film, realizing the exposure of the quasi-exposed region of the second photosensitive film;

[0029] After exposure, development, etching, and removal of the second photosensitive film are performed in sequence to obtain the corresponding bottom metal pattern.

[0030] A PCB includes a stepped groove, and the stepped groove is made according to the pattern manufacturing method of the stepped groove described in any one of the above.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] The sidewall-selective light-blocking mold of the embodiment of the present invention provides a light reflection function to change the exit path of the exposure light source, and also provides a local light-blocking function through the light-blocking pattern arranged in a partial region on the side surface of the light-transmitting body. Therefore, in the exposure process, the sidewall-selective light-blocking mold placed in the groove body of the stepped groove can reflect the irradiated exposure light source to the side wall of the groove body, and under the cooperative action of the light-blocking pattern, the exposure light source only irradiates the quasi-exposed region of the first photosensitive film on the side wall of the groove body, thereby realizing the selective exposure function of the first photosensitive film on the side wall of the groove body. Based on this sidewall-selective light-blocking mold, subsequent sidewall metal patterns that meet various shape design requirements can be manufactured according to conventional processes such as development and etching, which not only has a simple process but also has a high manufacturing accuracy. Description of the Drawings

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0034] Figure 1 It is a schematic diagram of the manufacturing method of the metal pattern on the sidewall of a conventional stepped groove and its graphic effect.

[0035] Figure 2 It is a schematic structural diagram of a sidewall selective light-blocking mold provided by an embodiment of the present invention.

[0036] Figure 3 For Figure 2 It is a schematic diagram of the replaceable structure of the installation cavity of the sidewall selective light-blocking mold shown.

[0037] Figure 4 For Figure 2 It is a schematic diagram of the application effect of the sidewall selective light-blocking mold shown.

[0038] Figure 5 It is a schematic structural diagram of another sidewall selective light-blocking mold provided by an embodiment of the present invention.

[0039] Figure 6 For Figure 5 It is a schematic diagram of the application effect of the sidewall selective light-blocking mold shown.

[0040] Figure 7 It is a flowchart of the method for manufacturing the pattern of the stepped groove provided by an embodiment of the present invention.

[0041] Figure 8 It is a schematic diagram of the structure and application effect of the film layer manufacturing mold provided by an embodiment of the present invention.

[0042] Figure 9 It is a flowchart of the method for manufacturing the metal pattern at the bottom of the groove provided by an embodiment of the present invention.

[0043] Figure 10 It is a schematic structural diagram of the bottom of the groove selective light-blocking mold provided by an embodiment of the present invention.

[0044] Reference numerals:

[0045] Sidewall selective light-blocking mold 1, first light-transmitting body 11, light-blocking pattern 12, light reflection unit 13;

[0046] PCB 2, first metal layer 21, first photosensitive film 22, photosensitive material 23, second metal layer 24, second photosensitive film 25;

[0047] Film layer manufacturing mold 3, mold body 31, material receiving cavity 32, flow channel 33, positioning mechanism 34, positioning pin 35;

[0048] Bottom of the groove selective light-blocking mold 4, second light-transmitting body 41, light-blocking substance 42. Detailed implementation manners

[0049] To make the invention objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0050] Embodiment 1

[0051] To solve the problem of manufacturing the sidewall metal pattern of the stepped groove in the prior art, the embodiment of the present invention provides a sidewall selective light-blocking mold 1, which can be applied to the groove body to achieve selective exposure of the first photosensitive film 22 covering the sidewall of the groove body, so as to realize the manufacture of sidewall metal patterns with high precision and arbitrary shapes.

[0052] It should be noted that for the convenience of description, the first photosensitive film 22 covering the entire sidewall of the groove body is divided into two parts according to the exposure manufacturing requirements: one part is the area that needs to be exposed in the exposure process, simply referred to as the area to be exposed. The photosensitive film in this area cannot be removed by the developing solution in the subsequent developing process because it undergoes a polymerization reaction with the exposure light source; the other part is the area that does not need to be exposed in the exposure process, simply referred to as the area not to be exposed. The photosensitive film in this area can be dissolved and removed by the developing solution in the subsequent developing process because it has not been exposed.

[0053] Specifically, please refer to Figure 2 , the sidewall selective light-blocking mold 1 provided by the embodiment of the present invention includes:

[0054] The first light-transmitting body 11, which matches the groove body of the stepped groove, and a light-blocking pattern 12 is provided on its side surface. The light-blocking pattern 12 corresponds to the area not to be exposed of the first photosensitive film 22 on the inner sidewall of the groove body;

[0055] The light reflection unit 13 is fixedly arranged in the first light-transmitting body 11 and is used to reflect the exposure light source incident from the top surface of the first light-transmitting body 11, so that the exposure light source exits from the area not covered by the light-blocking pattern 12 on the side surface of the first light-transmitting body 11 to the area to be exposed of the first photosensitive film 22.

[0056] The sidewall selective light-blocking mold 1 of the embodiment of the present invention provides a light reflection function to change the emission path of the exposure light source, and also provides a partial light-blocking function through the light-blocking pattern 12 arranged in a partial area on the side of the light-transmitting body. Therefore, in the exposure process, the sidewall selective light-blocking mold 1 placed in the groove body of the stepped groove can reflect the irradiated exposure light source to the sidewall of the groove body, and under the cooperative action of the light-blocking pattern 12, the exposure light source only irradiates the area to be exposed of the first photosensitive film 22 on the sidewall of the groove body, thereby realizing the selective exposure function of the first photosensitive film 22 on the sidewall of the groove body. Based on this sidewall selective light-blocking mold 1, subsequent conventional processes such as development and etching can be used to manufacture sidewall metal patterns that meet various shape design requirements, which is not only simple in process but also high in manufacturing accuracy.

[0057] In an alternative embodiment, an installation cavity is provided in the first light-transmitting body 11. In addition to the frustum structure as Figure 2 shown, it can also be a conical structure, a pyramid structure or a prismoid structure as Figure 3 shown. The light reflection unit 13 includes a reflector, and the reflector surrounds the sidewalls of the installation cavity.

[0058] For a groove body in the shape of a conventional rectangular body, since it includes four symmetrically arranged sidewalls, the installation cavity in the first light-transmitting body 11 can be selectively set to a conical structure, a frustum structure, a quadrangular pyramid structure or a quadrangular prismoid structure accordingly. In this way, the sidewalls in all directions of the installation cavity can be arranged in one-to-one correspondence with the sidewalls of the stepped groove body, so as to realize the selective exposure of the photosensitive films on different sidewalls through one exposure process, as Figure 4 shown.

[0059] To reduce the difficulty of optical path adjustment and ensure the position consistency between the actual exposure area of the first photosensitive film 22 and the preset area to be exposed, the included angle between the sidewall of the installation cavity and the bottom surface of the first light-transmitting body 11 is preferably 45 degrees. Of course, a certain range of tolerances is allowed in actual applications. In this way, when the exposure light source is vertically irradiated with the top surface of the first light-transmitting body 11 as the incident surface, the reflector can reflect the exposure light source by 90 degrees, so that the exposure light source exits perpendicular to the side of the first light-transmitting body 11, ensuring that the vertically projected area of the light-blocking pattern 12 on the first photosensitive film 22 is completely consistent with the preset area not to be exposed on the first photosensitive film 22, that is, ensuring the high consistency of the position between the actual exposure area of the first photosensitive film 22 and the preset area to be exposed, thereby further ensuring the manufacturing accuracy of the sidewall circuit pattern.

[0060] In another alternative embodiment, as Figure 5As shown, the installation cavity is a triangular prism structure. The intersection line of the first side and the second side of the triangular prism structure is the midline of the top surface of the first light-transmitting body 11. The bottom surface of the triangular prism structure is located on the side surface of the first light-transmitting body 11. The light reflection unit 13 includes a reflecting mirror, and the reflecting mirror is arranged on the first side and the second side of the installation cavity.

[0061] Similarly, optionally, the included angle between the first side of the triangular prism structure and the top surface of the first light-transmitting body 11, and the included angle between the second side of the triangular prism structure and the top surface of the first light-transmitting body 11 are both within a preset included angle range. The central value of the preset included angle range is 45 degrees to ensure the high consistency of the position between the actual exposure area of the first photosensitive film 22 and the preset planned exposure area, thereby further ensuring the manufacturing accuracy of the sidewall circuit pattern.

[0062] Based on Figure 5 the sidewall selective light-blocking mold 1 described above, the selective exposure of the four sidewall photosensitive films can be realized through two exposure processes. As Figure 6 shown, each exposure process is only used to realize the selective exposure of the two opposite sidewall photosensitive films.

[0063] Embodiment 2

[0064] Please refer to Figure 7 , the embodiment of the present invention provides a method for manufacturing a stepped groove pattern, including the steps:

[0065] Step 101: Provide a PCB 2 having a groove body and the sidewall selective light-blocking mold 1 as described in Embodiment 1.

[0066] The sidewall of the groove body is coated with a first metal layer 21, and the surface of the first metal layer 21 is coated with a first photosensitive film 22. The planned exposure area of the first photosensitive film 22 corresponds to the planned sidewall metal pattern to be manufactured.

[0067] Step 102: Place the sidewall selective light-blocking mold 1 into the groove body, and irradiate the exposure light source with the top surface of the first light-transmitting body 11 as the incident surface, so that after the exposure light source is reflected by the light reflection unit 13, it exits through the area of the side surface of the first light-transmitting body 11 that is not covered by the light-blocking pattern 12 to the planned exposure area of the first photosensitive film 22, realizing the exposure of the planned exposure area of the first photosensitive film 22.

[0068] Step 103: After exposure, develop, etch, and remove the first photosensitive film 22 in sequence to obtain the corresponding sidewall metal pattern.

[0069] It should be noted that in this step 103, specifically, the unexposed area of the first photosensitive film 22 can be removed by dissolution with developing solution according to the conventional process, so that part of the first metal layer 21 is exposed. Then, the exposed part of the first metal layer 21 is etched away, and finally the remaining part of the first photosensitive film 22 is removed, so that the first metal layer 21 at its bottom is exposed to the outside, forming a sidewall circuit pattern.

[0070] The method for fabricating the pattern of the stepped groove provided by the embodiment of the present invention replaces the traditional film with the sidewall selective light-blocking mold 1. Only by first placing the sidewall selective light-blocking mold 1 into the groove body of the stepped groove and then performing conventional processes applicable to the fabrication of the circuit pattern on the board surface, such as exposure, development, and etching, the fabrication of the sidewall pattern of the stepped groove can be realized. The process is not only simple, but also has high fabrication accuracy, and can realize the fabrication of patterns of any shape.

[0071] To facilitate the fabrication of the first photosensitive film 22 on the sidewall of the groove body, the embodiment of the present invention also provides a method for fabricating the first photosensitive film 22 on the surface of the first metal layer 21, including the steps of: pouring a liquid photosensitive material 23 into the groove body, and the photosensitive material 23 is a wet film or ink; pressing a film layer fabrication mold 3 into the groove body so that the photosensitive material 23 flows to cover the entire surface of the first metal layer 21 on the sidewall of the groove body; baking the photosensitive material 23 covering the surface of the first metal layer 21 at a high temperature until the photosensitive material 23 is cured to form a photosensitive film; taking out the film layer fabrication mold 3. Different from the conventional method of coating the liquid photosensitive material 23 and laminating the solid photosensitive film, this embodiment adopts a pressing method to enable the liquid photosensitive material 23 at the bottom of the groove body to naturally flow to the sidewall of the groove body and be cured to form the first photosensitive film 22, and the operation is simple and reliable.

[0072] Specifically, as Figure 8 shown, the film layer fabrication mold 3 may include: a mold body 31 with a material receiving cavity 32 provided therein, and a positioning mechanism 34 extending outward along the four peripheral edges of the top surface of the mold body 31.

[0073] Among them, the external dimension of the mold body 31 is smaller than the internal dimension of the groove body by a preset film layer thickness value on each side, and a flow channel 33 communicating the inside and outside of the receiving cavity is opened at the top end of the sidewall of the mold body 31. The direction of the flow channel 33 from its inlet end to its outlet end forms an acute angle with the corresponding sidewall.

[0074] During the process of pressing the film layer fabrication mold 3 from the top of the groove body to the bottom, the liquid photosensitive material 23 will flow from the bottom of the groove to the surrounding gaps and rise; when the film layer fabrication mold 3 is pressed in place, the excess photosensitive material 23 will flow into the material receiving cavity 32 of the mold body 31 through the flow channel 33 at the top end, and will not overflow to the outside, reducing material residue and facilitating cleaning.

[0075] The positioning mechanism 34 provided around the top surface of the mold body 31 can not only achieve the basic positioning function, connect with the processing table through the positioning pins 35 to ensure that the pressing position of the mold will not shift left and right, but also precisely control the pressing depth of the mold by adjusting the positioning depth of the positioning pins 35.

[0076] In addition, after the production of the sidewall metal pattern is completed, the embodiment of the present invention can continue with the production of the metal pattern on the bottom of the groove, such as Figure 9 shown, specifically including:

[0077] Step 201: Provide a PCB 2 with a groove, the bottom surface of the groove is covered with a second metal layer 24, and the surface of the second metal layer 24 is covered with a second photosensitive film 25.

[0078] Step 202: Produce a bottom-of-groove selective light-blocking mold 4 adapted to the groove.

[0079] Among them, as Figure 10 shown, the bottom-of-groove selective light-blocking mold 4 includes a second light-transmitting body 41; in the second light-transmitting body 41, in the area corresponding to the quasi-non-exposed area of the second photosensitive film 25, it is hollowed out and filled with a light-blocking substance 42 along the thickness direction, and the light-blocking substance 42 can block the exposure light source from passing through.

[0080] Step 203: Place the bottom-of-groove selective light-blocking mold 4 into the groove, and irradiate the exposure light source with the top surface of the second light-transmitting body 41 as the incident surface, so that the exposure light source exits through the area of the second light-transmitting body 41 where the light-blocking substance 42 is not filled to the quasi-exposed area of the second photosensitive film 25, realizing the exposure of the quasi-exposed area of the second photosensitive film 25.

[0081] After exposure, develop, etch, and remove the second photosensitive film 25 in sequence to obtain the corresponding metal pattern on the bottom of the groove.

[0082] Compared with the conventional method of realizing image transfer through a film, the embodiment of the present invention adopts a bottom-of-groove selective light-blocking mold 4 that matches the groove mechanism and size. The bottom-of-groove selective light-blocking mold 4 can effectively improve the exposure accuracy of the second photosensitive film 25 at the bottom of the groove, thereby improving the production accuracy of the metal pattern at the bottom of the groove.

[0083] It can be understood that the second photosensitive film 25 at the bottom of the groove can be obtained simultaneously with the first photosensitive film 22 on the sidewall in the process of manufacturing the mold 3 for the film layer to make the first photosensitive film 22. In practical applications, only the pressing depth of the film layer manufacturing mold 3 in the groove needs to be adjusted according to the thickness requirement of the second photosensitive film 25.

[0084] Embodiment III

[0085] An embodiment of the present invention further provides a PCB, which includes a stepped groove made according to the graphic manufacturing method of the stepped groove described in Embodiment 2.

[0086] Due to the adoption of the above special graphic manufacturing method of the stepped groove, the PCB of the embodiment of the present invention has high sidewall metal graphic accuracy and bottom metal graphic accuracy, effectively improving the product quality.

[0087] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sidewall selective light-blocking mold is applied to the inside of a groove of a PCB stepped groove to achieve selective exposure of a first photosensitive film (22) covering the sidewall of the groove, and is characterized in that, The sidewall selectively light-blocking mold (1) includes: A first light-transmissive body (11), which is matched with the structure of the groove body, and a light-blocking pattern (12) is provided on its side surface. The light-blocking pattern (12) corresponds to the quasi-unexposed area of the first photosensitive film (22); A light reflection unit (13) is fixedly arranged in the first light-transmissive body (11) and is used for reflecting the exposure light source incident from the top surface of the first light-transmissive body (11), so that the exposure light source exits through the area not covered by the light-blocking pattern (12) on the side surface of the first light-transmissive body (11) to the quasi-exposed area of the first photosensitive film (22).

2. The sidewall selectively light-blocking mold according to claim 1, wherein An installation cavity is provided in the first light-transmissive body (11). The installation cavity is in a conical structure, a frustum of a cone structure, a pyramid structure or a frustum of a pyramid structure, and the included angle between the side wall of the installation cavity and the bottom surface of the first light-transmissive body (11) is within a preset included angle range. The central value of the preset included angle range is 45 degrees; The light reflection unit (13) includes a reflecting mirror, and the reflecting mirror is arranged around the side wall of the installation cavity.

3. The sidewall selectively light-blocking mold according to claim 1, wherein An installation cavity is provided in the first light-transmissive body (11). The installation cavity is in a triangular prism structure. The intersection line of the first side surface and the second side surface of the triangular prism structure is the median line of the top surface of the first light-transmissive body (11), and the included angle between the first side surface and the top surface of the first light-transmissive body (11) and the included angle between the second side surface and the top surface of the first light-transmissive body (11) are both within a preset included angle range. The central value of the preset included angle range is 45 degrees; The light reflection unit (13) includes a reflecting mirror, and the reflecting mirror is arranged on the first side surface and the second side surface of the installation cavity.

4. A method for fabricating a pattern of a stepped groove, characterized in that, It includes the steps: Providing a PCB (2) with a groove body and the sidewall selectively light-blocking mold (1) according to any one of claims 1 to 3; a first metal layer (21) is covered on the side wall of the groove body, and a first photosensitive film (22) is covered on the surface of the first metal layer (21). The quasi-exposed area of the first photosensitive film (22) corresponds to the quasi-sidewall metal pattern to be fabricated; Placing the sidewall selectively light-blocking mold (1) into the groove body, and irradiating the exposure light source with the top surface of the first light-transmissive body (11) as the incident surface, so that after the exposure light source is reflected by the light reflection unit (13), it exits through the area not covered by the light-blocking pattern (12) on the side surface of the first light-transmissive body (11) to the quasi-exposed area of the first photosensitive film (22), realizing the exposure of the quasi-exposed area of the first photosensitive film (22); After exposure, development, etching and removal of the first photosensitive film (22) are carried out in sequence to obtain the corresponding sidewall metal pattern.

5. The method for fabricating the pattern of the stepped groove according to claim 4, wherein The method for fabricating the first photosensitive film (22) on the surface of the first metal layer (21) includes: Pouring a liquid photosensitive material (23) into the groove body. The photosensitive material (23) is a wet film or ink; Pressing a film layer fabricating mold (3) into the groove body, so that the photosensitive material (23) flows to cover the entire surface of the first metal layer (21) on the side wall of the groove body; The photosensitive material (23) covering the surface of the first metal layer (21) is baked at a high temperature until the photosensitive material (23) is cured to form the first photosensitive film (22); Take out the film layer manufacturing mold (3).

6. The method for manufacturing the pattern of the stepped groove according to claim 5, wherein The film layer manufacturing mold (3) includes: a mold body (31) with a material receiving cavity (32) provided therein; The outer dimension of the mold body (31) is smaller than the inner dimension of the groove body by a preset film layer thickness value on each side, and a flow channel (33) communicating the inside and outside of the receiving cavity is provided at the top end of the side wall of the mold body (31).

7. The method for fabricating the pattern of the stepped groove according to claim 6, wherein The included angle between the direction of the flow channel (33) from its inlet end to its outlet end and the corresponding side wall is an acute angle.

8. The method for fabricating the pattern of the stepped groove according to claim 6, characterized in that, A positioning mechanism (34) is formed by extending the top surface of the mold body (31) outward along its four peripheries.

9. The method for fabricating the pattern of the stepped groove according to claim 4, wherein The bottom surface of the groove body is covered with a second metal layer (24), and the surface of the second metal layer (24) is covered with a second photosensitive film (25); The pattern manufacturing method further includes: Manufacturing a bottom groove selective light-blocking mold (4) adapted to the groove body, the bottom groove selective light-blocking mold (4) including a second light-transmitting body (41); in the area of the second light-transmitting body (41) corresponding to the quasi-non-exposed area of the second photosensitive film (25), it is hollowed out and injected with a light-blocking substance (42) along the thickness direction; Place the bottom groove selective light-blocking mold (4) into the groove body, and irradiate an exposure light source with the top surface of the second light-transmitting body (41) as the incident surface, so that the exposure light source exits through the area of the second light-transmitting body (41) where the light-blocking substance (42) is not injected to the quasi-exposed area of the second photosensitive film (25), realizing the exposure of the quasi-exposed area of the second photosensitive film (25); After exposure, development, etching, and removal of the second photosensitive film (25) are performed in sequence to obtain a corresponding bottom groove metal pattern.

10. A PCB, comprising a stepped groove, characterized in that, The stepped groove is made according to the pattern manufacturing method of the stepped groove according to any one of claims 4 to 9.

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