CN115379661A - Printed circuit board and preparation method thereof - Google Patents

Abstract

The invention discloses a printed circuit board and a preparation method thereof, wherein the preparation method of the printed circuit board comprises the following steps: obtaining a plate to be processed; thickening a first preset position of the metal layer of the plate to be processed to form a boss; arranging a solder mask on the surface of one side of the plate to be processed, wherein the boss is formed on the surface of the plate to be processed, and the solder mask covers the whole surface of the surface of one side of the plate to be processed; and grinding the solder mask layer to expose the surface of one side of the boss far away from the metal layer. By the mode, the solder mask exposure efficiency of the printed circuit board can be greatly improved, the exposure requirement is reduced, the printed circuit board after solder mask is prevented from being developed, the problem that the solder mask printed circuit board is likely to have bottom lateral erosion is solved from the source, and the quality of the printed circuit board is improved.

Description

Printed circuit board and preparation method thereof

Technical Field

The invention is applied to the technical field of processing printed circuit boards, and particularly relates to a printed circuit board and a preparation method thereof.

Background

A Printed Circuit Board (PCB), also called Printed Circuit Board or Printed Circuit Board, is an important electronic component used in a wide range of applications, is a support for electronic components, and is also a carrier for electrical connection of electronic components.

In the existing preparation method of the printed circuit board, the solder mask layer is often processed in a film exposure and development mode so as to expose the part to be soldered. However, when exposure is carried out, the solder mask can be because of its thickness makes the easy solidification of solder mask bottom incomplete, leads to follow-up developing liquid medicine to cause the bottom undercut of certain degree to the solder mask bottom easily when developing the plate to lead to solder mask edge to drop or bottom undercut position to hide liquid medicine/foreign matter, and then influence printed circuit board quality.

Disclosure of Invention

The invention provides a printed circuit board and a preparation method thereof, which aim to solve the problem of side etching of the bottom of the printed circuit board.

In order to solve the technical problem, the invention provides a method for preparing a printed circuit board, which comprises the following steps: obtaining a plate to be processed; thickening a first preset position of a metal layer of a plate to be processed to form a boss; arranging a solder mask on the surface of one side of the plate to be processed, wherein the boss is formed on the surface of the plate to be processed, and the solder mask covers the whole surface of the surface of one side of the plate to be processed; and carrying out whole-plate grinding on the solder mask layer to expose the surface of one side of the boss far away from the metal layer.

Wherein, be formed with the solder mask in the side surface of boss at the board of waiting to process, wherein, the solder mask covers the step of the whole face of the side surface of waiting to process the board and includes: printing ink on the whole plate on the surface of one side of the plate to be processed, which is provided with the boss, until the ink completely covers the surface of one side of the plate to be processed, which is provided with the boss; and carrying out whole-surface exposure on the surface of one side of the plate to be processed, which is printed with the ink, so as to solidify the ink and form a solder mask.

Wherein, be formed with the solder mask in the side surface of boss at the board of waiting to process, wherein, the solder mask covers the step of the whole face of the side surface of waiting to process the board and includes: and (5) pasting the whole solder mask dry film plate on the surface of one side of the plate to be processed, which is provided with the boss, so as to form a solder mask layer.

Wherein, carry out whole board to grind to the solder mask to the step that exposes the boss and keeps away from the one side surface of metal level includes: and (3) carrying out surface layer grinding on the solder mask layer from one side of the solder mask layer far away from the boss to the direction of the solder mask layer by means of leveling, plate brushing, laser ablation, ion cutting, ion polishing or water jet until the side surface of the exposed boss far away from the metal layer.

Wherein, the step of obtaining the plate to be processed comprises: obtaining a copper-clad plate; forming at least one hole on the copper-clad plate by drilling, wherein the hole comprises a through hole and a micro blind hole; and carrying out hole treatment on at least one hole to obtain the plate to be processed.

Wherein the hole treatment comprises copper deposition treatment, black hole treatment or shadow treatment.

The method comprises the following steps of thickening a first preset position of a metal layer of a plate to be processed to form a boss: pasting a first photosensitive film on a metal layer of a plate to be processed, and exposing a first preset position; electroplating a first preset position of a plate to be processed to form a boss at the first preset position; and removing the first photosensitive film on the plate to be processed.

Wherein, treat the first preset position of the metal level of processing plate and carry out the bodiness to after the step of formation boss, including before the step of setting up the solder mask at the side surface that is formed with the boss of treating processing plate: pasting a second photosensitive film on a second preset position of the plate to be processed, and etching the plate to be processed to form a conductive circuit on the plate to be processed; and removing the second photosensitive film on the plate to be processed.

Wherein, carry out whole board to grind to the solder mask to the step of exposing the boss and keeping away from the one side surface of metal level includes afterwards: and controlling the depth of the boss until the thickness of the boss meets the preset height.

In order to solve the technical problem, the invention also provides a printed circuit board which is prepared by the preparation method of any one of the printed circuit boards.

The invention has the advantages that; different from the situation of the prior art, the first preset position of the metal layer of the plate to be processed is thickened to form a boss; and arranging a solder mask layer on the whole surface of one side of the plate to be processed, wherein the boss is formed on the whole surface, and finally, carrying out whole-plate grinding on the solder mask layer to expose one side surface of the boss, which is far away from the metal layer, so that the solder mask operation of a first preset position of the printed circuit board is completed in a mode of carrying out directional thickening, whole-plate solder mask and whole-plate grinding on the boss, the step of carrying out film development on the printed circuit board is avoided, the problem that the bottom of the solder mask layer is subjected to lateral erosion due to development is solved fundamentally, and the quality and the reliability of the printed circuit board are improved.

Drawings

FIG. 1 is a schematic flow chart of an embodiment of a method for manufacturing a printed wiring board according to the present invention;

FIG. 2 is a schematic flow chart showing another embodiment of the method for manufacturing a printed wiring board according to the present invention;

FIG. 3a is a schematic structural diagram of an embodiment of the plate to be processed in step S21;

fig. 3b is a schematic structural diagram of an embodiment of the board to be processed after the first photosensitive film is attached in step S22;

fig. 3c is a schematic structural diagram of an embodiment of the to-be-processed plate after the first photosensitive film is removed in step S22;

fig. 3d is a schematic structural diagram of an embodiment of the to-be-processed plate after the second photosensitive film is attached in step S23;

fig. 3e is a schematic structural diagram of an embodiment of the plate to be processed after the second photosensitive film is removed in step S23;

fig. 3f is a schematic structural diagram of the embodiment after the solder mask layer is formed in step S24;

fig. 4 is a schematic structural diagram of an embodiment of the printed wiring board of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative position relationship between the components, the motion situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In addition, technical solutions between the embodiments may be combined with each other, but must be based on the realization of the technical solutions by a person skilled in the art, and when the technical solutions are contradictory to each other or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

Referring to fig. 1, fig. 1 is a schematic flow chart of an embodiment of a method for manufacturing a printed circuit board according to the present invention.

Step S11: and obtaining the plate to be processed.

The board to be processed in this embodiment may be a single-layer circuit board or a multilayer circuit board, where the multilayer circuit board in this embodiment includes two layers of circuit boards and more than two layers of circuit boards.

In a specific application scenario, the plate to be processed can be a copper-clad plate, and can also be a multi-layer circuit board which is already pressed in the processing process. Among them, a Copper Clad Laminate (CCL) is an original plate-shaped material prepared by impregnating an electronic glass fabric or other reinforcing materials with resin, coating one or both surfaces with Copper foil, and hot-pressing.

Step S12: and thickening the first preset position of the metal layer of the plate to be processed to form a boss.

And directionally thickening the first preset position of the metal layer of the plate to be processed to form a boss. The metal layer of the plate to be processed is arranged on at least one side of the plate to be processed. In a specific application scenario, the metal layer may be disposed on one side of the board to be processed. In another specific application scenario, the metal layers may also be disposed on opposite sides of the board to be processed.

The first preset position of the embodiment refers to a part of the board to be processed, where solder resist is required to be performed. The first preset position may be a plurality of spaced positions or a single position, and may be specifically set based on the solder resist requirement, which is not limited herein.

In a specific application scenario, the copper-containing electroplating solution is coated at the first preset position, and the first preset position is electroplated, so that the metal layer is thickened at the first preset position to form the boss.

In a specific application scenario, copper deposition can be performed at a first preset position of a plate to be processed, so that a metal layer is thickened at the first preset position, and a boss is formed at the first preset position. And are not limited herein.

Step S13: and arranging a solder mask on the surface of one side of the plate to be processed, wherein the boss is formed on the surface of one side of the plate to be processed, and the solder mask covers the whole surface of the surface of one side of the plate to be processed.

The plate to be processed is subjected to resistance welding processing, a resistance welding layer is arranged on one side surface of the plate to be processed, which is provided with the boss, and the resistance welding layer covers the whole side of one side surface of the plate to be processed, which is provided with the boss, after the resistance welding is finished.

In a specific application scenario, when the side surface of the board to be processed, on which the boss is formed, is a single-side surface, the solder resist layer covers the whole surface of the single-side surface of the board to be processed, on which the boss is formed. In another specific application scenario, when the bosses are formed on the two opposite side surfaces of the board to be processed, the solder resist layer covers the whole surfaces of the two opposite side surfaces of the board to be processed, on which the bosses are formed.

Step S14: and grinding the solder mask layer to expose the surface of one side of the boss far away from the metal layer.

And carrying out whole-plate grinding on the solder mask layer on the plate to be processed so as to thin the whole solder mask layer on the plate to be processed until the surface of one side of the lug boss, which is far away from the metal layer, is exposed. At the moment, the surface of one side of the boss, which is far away from the metal layer, is flush with the solder mask layer on the same side of the boss. And the residual solder mask layer on the same side as the boss covers the first preset position on the plate to be processed, so that the solder mask operation of the first preset position of the plate to be processed is completed.

In a specific application scenario, when the single boss of the plate to be processed is multiple, after grinding is finished, the surface of one side, away from the metal layer, of each boss is flush with the solder mask layer on the same side of the boss.

In such a way, according to the preparation method of the printed circuit board, the first preset position of the metal layer of the plate to be processed is thickened to form the boss; and arranging a solder mask layer on the whole surface of one side of the plate to be processed, wherein the boss is formed on the whole surface, and finally, carrying out whole-plate grinding on the solder mask layer to expose the surface of one side of the boss, which is far away from the metal layer, so that the solder mask operation of a first preset position of the printed circuit board is completed in a mode of carrying out directional thickening, whole-plate solder mask and whole-plate grinding on the boss, the step of carrying out film development on the printed circuit board is avoided, the problem that the bottom of the solder mask layer is subjected to lateral erosion possibly caused by development is solved fundamentally, and the quality and the reliability of the printed circuit board are improved.

Referring to fig. 2, fig. 2 is a schematic flow chart of another embodiment of a method for manufacturing a printed circuit board according to the present invention. In this embodiment, a board to be processed is taken as an example of a single-layer circuit board, where the preparation of the multi-layer circuit board is similar to the single-layer circuit board and is not described again.

Step S21: and drilling the obtained copper-clad plate to form at least one hole on the copper-clad plate, and carrying out hole treatment on the at least one hole to obtain the plate to be processed.

And obtaining the copper-clad plate. The copper-clad plate comprises a dielectric layer and a metal layer, wherein one side of the dielectric layer can be covered with the metal layer, and the other side of the dielectric layer can be covered with the metal layer. In this embodiment, a double-sided metal layer covering a dielectric layer of a copper-clad plate will be taken as an example for explanation. The dielectric layer is made of epoxy resin, polyimide, BT, ABF, ceramic and other material.

And drilling the copper-clad plate to drill at least one hole on the copper-clad plate. In a specific application scenario, the copper-clad plate may be drilled by mechanical drilling to drill at least one hole in the copper-clad plate. In a specific application scenario, the copper-clad plate can be drilled through the laser drilling hole, so that at least one hole is drilled in the copper-clad plate.

The holes in this step include through holes and blind micro-vias. The through hole is a hole which penetrates through the whole copper-clad plate and is penetrated up and down; the micro blind hole refers to a through hole which connects two adjacent layers without being penetrated. In the step, the through hole and the micro blind hole on the copper-clad plate both penetrate through the dielectric layer of the copper-clad plate, the through hole penetrates through the whole copper-clad plate, and the micro blind hole penetrates through the metal layer on one side of the copper-clad plate and the middle dielectric layer without penetrating through the metal layer on the other side of the copper-clad plate.

And drilling the copper-clad plate to drill at least one hole on the copper-clad plate. In a specific application scenario, a plurality of through holes or micro blind holes can be drilled on a copper-clad plate, for example: 3, 5 and 10, the specific number of the holes can be set according to the conduction requirement of the printed circuit board, and is not limited herein. In a specific application scenario, after laser drilling or mechanical drilling is performed on the copper-clad plate and at least one hole is drilled in the copper-clad plate, resin residues, copper residues and the like possibly remain in the hole in the copper-clad plate and are subjected to dirt drilling treatment, so that the hole in the copper-clad plate needs to be subjected to dirt drilling removal treatment in the step so as to clean the hole in the copper-clad plate.

And carrying out hole treatment on the hole on the copper-clad plate to obtain the plate to be processed in the embodiment. Wherein the hole treatment comprises copper deposition treatment, black hole treatment or shadow treatment. The hole on the copper-clad plate is subjected to hole treatment, so that the hole wall or/and the hole bottom of the hole is/are covered with a layer of conductive material, and subsequent electroplating is facilitated. Wherein, the black hole treatment refers to that fine graphite or carbon black coating (black hole liquid) is coated on the hole wall or/and the hole bottom of the hole in a dipping way to form a conductive layer; the shadow treatment refers to that the shadow solution containing the unique additive and the conductive colloidal substance is coated on the hole wall or/and the hole bottom of the hole in a dipping way, so that a conductive layer is formed on the hole wall or/and the hole bottom; the copper deposition treatment is to deposit a thin layer of chemical copper on the hole wall and/or the hole bottom of the hole by a chemical method to serve as a substrate for electroplating.

Referring to fig. 3a, fig. 3a is a schematic structural diagram of an embodiment of the plate to be processed in step S21.

The board 100 to be processed of the present embodiment includes an upper metal layer 1021, a dielectric layer 101, and a lower metal layer 1022. The upper metal layer 1021, the dielectric layer 101, and the lower metal layer 1022 are sequentially stacked and attached to each other. The plate 100 to be processed is provided with a micro blind hole 103 and a through hole 104. The micro blind hole 103 penetrates through the upper metal layer 1021 and the dielectric layer 101, the bottom of the micro blind hole 103 is formed by the lower metal layer 1022, and the through hole 104 penetrates through the upper metal layer 1021, the dielectric layer 101 and the lower metal layer 1022.

The embodiment only shows the structures of the through holes and the micro blind holes, and does not limit the number and the structures of the holes on the plate to be processed in the actual production process.

Step S22: and attaching a first photosensitive film on the metal layer of the plate to be processed, exposing the first preset position, electroplating the first preset position of the plate to be processed to form a boss at the first preset position, and removing the first photosensitive film on the plate to be processed.

And pasting a first photosensitive film on the metal layer of the plate to be processed, and exposing the first preset position. In a specific application scenario, the first photosensitive film may be a photosensitive resist film or other photosensitive films, wherein the photosensitive resist film is a high molecular compound, and can generate a polymerization reaction (a reaction process of synthesizing a polymer from a monomer) after being irradiated by a specific light source to form a stable substance to be attached to the surface of the board, thereby achieving the function of blocking electroplating.

The first preset position of the embodiment refers to a part of the board to be processed, where solder resist is not needed. The first predetermined location includes, but is not limited to, the orifice of each hole and the vicinity of the perimeter of the hole.

Electroplating the first preset position of the plate to be processed, so that the first preset position is directionally thickened, a boss is formed at the first preset position, and the first photosensitive film on the plate to be processed is removed after the boss is formed.

After the holes in the plates to be processed are electroplated, the holes can be metallized, and interlayer interconnection among the plates is realized.

Referring to fig. 3b, fig. 3b is a schematic structural diagram of an embodiment of the board to be processed after the first photosensitive film is attached in step S22.

The board 200 to be processed in this embodiment includes an upper first photosensitive film 2051, an upper metal layer 2021, a dielectric layer 201, a lower metal layer 2022, and a lower first photosensitive film 2052. The upper first photosensitive film 2051, the upper metal layer 2021, the dielectric layer 201, the lower metal layer 2022, and the lower first photosensitive film 2052 are sequentially stacked and attached to each other. The plate 200 to be processed is provided with a micro blind hole 203 and a through hole 204. The upper and lower first photosensitive films 2051 and 2052 do not cover the first preset position 206. The specific position of the first preset position 206 may depend on the solder mask requirement.

Electroplating is performed on a first preset position 206 of the plate 200 to be processed, so as to perform hole metallization on the micro blind holes 203 and the through holes 204, and simultaneously, the copper thickness of the first preset position 206 is directionally increased, so as to form a boss (not shown in the figure) on the first preset position 206, and after the electroplating is completed, the upper first photosensitive film 2051 and the lower first photosensitive film 2052 on the plate 200 to be processed are removed.

In this step, after a first photosensitive film is attached to the surface of the plate to be processed, a first predetermined position of the plate to be processed is electroplated to thicken the metal layer at the first predetermined position, thereby forming a boss (also called copper pillar or copper base). And after the electroplating is finished, removing the first photosensitive film on the plate to be processed.

Referring to fig. 3c, fig. 3c is a schematic structural diagram of an embodiment of the to-be-processed board after the first photosensitive film is removed in step S22.

The plate member to be processed 300 of the present embodiment includes: a plurality of mesas 307, an upper metal layer 3021, a dielectric layer 301, and a lower metal layer 3022. The upper metal layer 3021, the dielectric layer 301, and the lower metal layer 3022 are sequentially stacked and attached to each other. Wherein, the upper metal layer 3021 is provided with a boss 307 on the side away from the dielectric layer 301. The side of the lower metal layer 3022 away from the dielectric layer 301 is provided with a boss 307. The thickness of the mesa 307 on the upper metal layer 3021 is greater than the thickness of the upper metal layer 3021. The thickness of the mesa 307 on the lower metal layer 3022 is greater than the thickness of the lower metal layer 3022.

Step S23: and pasting a second photosensitive film on a second preset position of the plate to be processed, etching the plate to be processed to form a conductive circuit on the plate to be processed, and removing the second photosensitive film on the plate to be processed.

Based on the demand of figure transfer, paste on the second preset position of waiting to process the plate and cover the second photosensitive film, that is, paste on the second preset position of the upper metal level of waiting to process the plate and lower floor's metal level and cover the second photosensitive film to treat to process the plate and carry out the figure etching, form the conducting wire on the upper metal level of waiting to process the plate and lower floor's metal level, in order to realize waiting to process the function that switches on of plate. And after the pattern etching is finished, removing the second photosensitive film on the plate to be processed. The second photosensitive film may be a photosensitive resist film, which is a high molecular compound capable of generating a polymerization reaction (a reaction process of synthesizing a polymer from a monomer) after being irradiated by a specific light source to form a stable substance attached to the plate surface, thereby achieving the function of etching barrier. The second preset position is the position where the conducting circuit and the boss need to be manufactured on the plate to be processed.

And after the conductive circuit is formed on the plate to be processed, removing the second photosensitive film on the plate to be processed.

Referring to fig. 3d, fig. 3d is a schematic structural diagram of an embodiment of the board to be processed after the second photosensitive film is attached in step S23.

The board 400 to be processed in this embodiment includes a second photosensitive film 408, an upper metal layer 4021, a boss 407, a dielectric layer 401, and a lower metal layer 4022. The second photosensitive film 408, the boss 407, the upper metal layer 4021, the dielectric layer 401, the lower metal layer 4022, the boss 407, and the second photosensitive film 408 are sequentially stacked and attached. A plurality of second photosensitive films 408 are disposed on the upper metal layer 4021 and one side of the corresponding boss 407 away from the dielectric layer 401. A plurality of second photosensitive films 408 are disposed on the lower metal layer 4022 and one side of the corresponding boss 407 away from the dielectric layer 401. The surface of each boss 407 away from the dielectric layer 401 is covered with a second photosensitive film 408 to protect the boss 407. The upper metal layer 4021 and the lower metal layer 4022 are far away from one side of the dielectric layer 401, and the positions not covered by the second photosensitive film 408 are positions where conductive traces and bosses do not need to be manufactured.

The board 400 to be processed is etched to etch conductive traces on the upper metal layer 4021 and the lower metal layer 4022. After the etching is completed, the second photosensitive film 408 on the board 400 to be processed is removed.

Referring to fig. 3e, fig. 3e is a schematic structural diagram of an embodiment of the to-be-processed board after the second photosensitive film is removed in step S23.

The plate 500 to be processed in this embodiment includes a boss 507, a dielectric layer 501, and a conductive trace 5122. The thickness of land 507 is greater than the thickness of conductive trace 5122. The upper metal layer and the lower metal layer are patterned to form the conductive traces 5122 on the board 500 to be processed. While each land 507 is unaffected by the pattern etch.

Step S24: printing ink on the whole surface of one side of the plate to be processed, which is provided with the boss, until the ink completely covers the surface of one side of the plate to be processed, which is provided with the boss, and carrying out whole-surface exposure on the surface of one side of the plate to be processed, which is printed with the ink, so as to solidify the ink and form a solder mask.

And printing ink on the whole plate on the surface of the side, provided with the boss, of the plate to be processed until the ink completely covers the surface of the side, provided with the boss, of the plate to be processed. And after printing, carrying out whole-surface exposure on the surface of the side, printed with the ink, of the plate to be processed so as to solidify the ink and form a solder mask.

The exposure of the step does not use film, and the whole surface exposure is directly carried out, so that the printing ink is completely reacted and solidified.

Referring to fig. 3f, fig. 3f is a schematic structural diagram of the embodiment after the solder mask layer is formed in step S24.

The outermost layer of the board 600 to be processed of the present embodiment is entirely covered with the solder resist layers 608 on opposite sides. The solder mask 608 covers two opposite sides of the board 600 to be processed, and includes the exposed bosses 607, the conductive traces 6122 and the dielectric layer 601 on the two opposite sides of the board 600 to be processed.

Other structures of the plate 600 to be processed in this embodiment, for example, the structure, the thickness, and the like between the boss 607 and the conductive trace 6122, are the same as those of the plate 500 to be processed in fig. 3e, and please refer to the foregoing, which is not described herein again.

Step S25: and (3) carrying out surface layer grinding on the solder mask layer from one side of the solder mask layer far away from the boss to the direction of the solder mask layer by means of leveling, plate brushing, laser ablation, ion cutting, ion polishing or water jet until the side surface of the exposed boss far away from the metal layer.

After a solder mask layer is formed on the whole surface of one side of the plate to be processed, which is provided with the boss, the solder mask layer is subjected to surface layer grinding in a shoveling, brushing, laser ablation, ion cutting, ion polishing or water jet mode from one side of the solder mask layer far away from the boss to the direction of the solder mask layer until the side surface of the boss far away from the metal layer is exposed. After the grinding is finished, the surface of one side, away from the metal layer, of each boss is flush with the solder mask layer on the same side of the boss.

After grinding, the solder mask still covers the conducting circuit and the dielectric layer, so that the conducting circuit and the dielectric layer are protected through the solder mask.

This step exposes the surface of first boss through the mode that whole board ground, because first boss has carried out directional bodiness in advance, consequently, when this step ground out the surface of first boss, accomplish promptly and set up the solder mask in the operation of hindering of corresponding position, and expose first boss, in order to be used for the welding, this step need not to develop the plate and makes the solder mask expose the surface of first boss, avoided the etching of developer solution to the solder mask, consequently, the solder mask of this embodiment has solved the problem of welding mask bottom undercut from the root cause.

In such a way, according to the preparation method of the printed circuit board, the first preset position of the metal layer of the plate to be processed is thickened to form the boss; and arranging a solder mask layer on the whole surface of one side of the plate to be processed, wherein the boss is formed on the whole surface, and finally, carrying out whole-plate grinding on the solder mask layer to expose one side surface of the boss, which is far away from the metal layer, so that the solder mask operation of a first preset position of the printed circuit board is completed in a mode of carrying out directional thickening, whole-plate solder mask and whole-plate grinding on the boss, the step of carrying out film development on the printed circuit board is avoided, the problem that the bottom of the solder mask layer is subjected to lateral erosion due to development is solved fundamentally, and the quality and the reliability of the printed circuit board are improved.

In other embodiments, the manner of forming the solder resist layer in step S24 may further include: and (5) pasting the whole solder mask dry film plate on the surface of one side of the plate to be processed, which is provided with the boss, so as to directly form a solder mask layer. The solder resist dry film is a kind of photo solder resist, is in a semi-solidified state, has certain fluidity and filling property when being pressed, is a protective layer, and is attached to a circuit and a base material which are not required to be welded on a plate. The purpose is to protect the formed conductive circuit for a long time.

In a specific application scene, a solder mask dry film can be attached to the whole surface of one side of the plate to be processed, which is provided with the boss, in a vacuumizing mode, so that the solder mask dry film is attached to the exposed boss, the dielectric layer and the conducting circuit.

In other embodiments, the step after the step S25 may further include controlling the depth of the projection on the surface of the side away from the metal layer until the thickness of the projection satisfies a preset height. Wherein, the setting of the preset height can be determined based on the welding requirement of the printed circuit board. And whether depth control of the boss is required can also be determined based on welding requirements.

In this step, the height of the boss is reduced, and the thickness of the solder resist layer is not reduced. And after depth control, the height of the solder mask is higher than that of the lug boss.

In a specific application scenario, the thickness of the boss may be reduced to a predetermined height by microetching or other chemical copper reduction. In another specific application scenario, the thickness of the boss may be reduced to a predetermined height by UV laser drill ablation or laser milling. In another specific application scenario, the thickness of the boss can be reduced to a preset height by means of CO2 laser drill ablation.

Referring to fig. 4, fig. 4 is a schematic structural diagram of a printed wiring board according to an embodiment of the present invention.

Printed wiring board 700 of the present embodiment includes dielectric layer 701, conductive line 7122, a plurality of bosses 707, and solder resist layer 708. A plurality of bosses 707, a conductive trace 7122, and a solder resist layer 708 are disposed on opposite sides of the dielectric layer 701. Solder mask 708 fills in the opposite sides of printed wiring board 700 to cover the exposed dielectric layer 701 and conductive traces 7122, and is flush with the surface of the side of boss 707 remote from dielectric layer 701. And the thickness of boss 707 is greater than the thickness of conductive trace 7122.

Here, the printed wiring board 700 of the present embodiment is obtained by the method for manufacturing a printed wiring board according to any one of the above embodiments.

The solder mask layer of the printed circuit board of the embodiment is not developed, bottom side etching does not exist at the bottom of the solder mask layer, the solder mask layer of the embodiment can well protect the conductive circuit, and the quality and the reliability of the printed circuit board are improved.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (10)

1. A method for manufacturing a printed wiring board is characterized by comprising the following steps:

obtaining a plate to be processed;

thickening a first preset position of the metal layer of the plate to be processed to form a boss;

arranging a solder mask on the surface of one side of the plate to be processed, wherein the boss is formed on the surface of the plate to be processed, and the solder mask covers the whole surface of the surface of one side of the plate to be processed;

and carrying out whole-plate grinding on the solder mask layer to expose the surface of one side of the boss, which is far away from the metal layer.

2. The method for manufacturing a printed wiring board according to claim 1, wherein a solder resist layer is provided on a surface of the board to be processed on which the boss is formed, and wherein the step of covering an entire surface of the board to be processed with the solder resist layer comprises:

printing ink on the whole surface of one side of the plate to be processed, which is provided with the boss, until the ink completely covers the surface of one side of the plate to be processed, which is provided with the boss;

and carrying out whole surface exposure on the surface of one side of the plate to be processed, on which the printing ink is printed, so as to solidify the printing ink and form the solder mask.

3. The method for manufacturing a printed wiring board according to claim 1, wherein a solder resist layer is provided on a surface of the board to be processed on which the boss is formed, and wherein the step of covering an entire surface of the board to be processed with the solder resist layer comprises:

and (3) pasting the whole solder mask dry film plate on the surface of one side of the plate to be processed, which is provided with the boss, so as to form the solder mask layer.

4. The method for manufacturing a printed wiring board according to claim 1, wherein the step of performing full-plate grinding on the solder resist layer to expose a surface of the boss on a side away from the metal layer comprises:

and (3) carrying out surface layer grinding on the solder mask layer in a direction from one side of the solder mask layer far away from the boss to the solder mask layer in a mode of leveling, brushing a plate, laser ablation, ion cutting, ion polishing or water jet cutting until the side surface of the boss far away from the metal layer is exposed.

5. The method for manufacturing a printed wiring board according to claim 1, wherein the step of obtaining the board to be processed comprises:

obtaining a copper-clad plate;

forming at least one hole on the copper-clad plate by drilling, wherein the hole comprises a through hole and a micro blind hole;

and carrying out hole treatment on at least one hole to obtain the plate to be processed.

6. The method for producing a printed wiring board according to claim 5,

the hole treatment comprises copper deposition treatment, black hole treatment or shadow treatment.

7. The method for manufacturing a printed wiring board according to claim 5, wherein the step of thickening the first predetermined position of the metal layer of the board to be processed to form the boss comprises:

pasting a first photosensitive film on the metal layer of the plate to be processed, and exposing the first preset position;

electroplating a first preset position of the plate to be processed to form a boss at the first preset position;

and removing the first photosensitive film on the plate to be processed.

8. The method for manufacturing a printed wiring board according to claim 1, wherein after the step of thickening the first preset position of the metal layer of the board to be processed to form the boss, the step of providing a solder resist layer on the surface of the board to be processed on the side where the boss is formed comprises:

attaching a second photosensitive film on a second preset position of the plate to be processed, and etching the plate to be processed to form a conductive circuit on the plate to be processed;

and removing the second photosensitive film on the plate to be processed.

9. The method for manufacturing a printed wiring board according to claim 1, wherein the step of performing full-plate grinding on the solder resist layer to expose a surface of the boss on a side away from the metal layer is followed by:

and controlling the depth of the boss until the thickness of the boss meets the preset height.

10. A printed wiring board produced by the method for producing a printed wiring board according to any one of claims 1 to 9.

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