CN114222420A - Circuit board local metallization edge-covering lamination structure and processing technology thereof - Google Patents

Abstract

The invention provides a circuit board local metallization edge-covering laminated structure and a processing technology thereof, wherein the circuit board local metallization edge-covering laminated structure comprises the following steps: first core, first fluidity PP layer, second core, the fluidity PP layer of second and third core that from top to bottom set gradually, all be formed with electrically conductive metal strip on first core, second core and the third core, the orientation of first core the second core one side be formed with first blind groove on the surface, the orientation of third core the second core one side be formed with the blind groove of second on the surface, first logical groove has been seted up on the fluidity PP layer of first. According to the invention, all layers do not need to be metalized and edged in advance, and then depth control milling is carried out, so that the redundant layers of metalized and edged are milled and etched, thus the problems that the metalized and edged layers are damaged by milling depth and the size and quality of the unit are influenced due to depth control milling are avoided, and meanwhile, mass production and manufacturing can be realized.

Description

Circuit board local metallization edge-covering lamination structure and processing technology thereof

Technical Field

The invention relates to the field of circuit board manufacturing, in particular to a circuit board local metallization edge-covered laminated structure and a processing technology thereof.

Background

For a high-frequency and high-speed PCB circuit board, metallization edge covering is required to be carried out on a board edge groove to form a metallized board edge groove, so that microwave signals cannot be radiated out from the edge of the PCB. The existing metallization edge covering process is basically all levels of metallization edge covering at present. When the plate is in a local-level metallization edge covering structure, the current industry general method is to firstly carry out all-level metallization edge covering, then carry out depth-controlled milling, mill off redundant level metallization edge covering and then etch.

The local edge covering process in the prior art comprises the following steps: cutting → inner layer etching → laminating → drilling → milling metal slot hole (containing edge covering) → copper deposition → plate plating → external light imaging → pattern plating → controlled depth milling → milling half hole → outer layer etching → solder resisting → character → gold deposition → post process.

The defect that redundant layers of metallized covered edges are milled in depth control mode: (1) the depth tolerance of the conventional depth control milling is +/-0.15 mm, the precision is low, and the milling depth often damages a metalized edge covering layer to influence the quality and cause scrapping; (2) similar designs cannot be mass produced; (3) because the depth control milling needs to mill the redundant metallization edge tin layer in the unit, the risk of influencing the unit size is generated.

Disclosure of Invention

The invention provides a circuit board local metallization edge-covered laminated structure and a processing technology thereof, and aims to solve at least one technical problem.

To solve the above problems, as an aspect of the present invention, there is provided a circuit board partial metallization edge-clad laminate structure, including: first core, first non-mobile PP layer, second core, the non-mobile PP layer of second and third core that from top to bottom set gradually, all be formed with electrically conductive metal strip on first core, second core and the third core, the orientation of first core the second core one side be formed with first blind groove on the surface, the orientation of third core the second core one side be formed with the blind groove of second on the surface, first logical groove has been seted up on the first non-mobile PP layer, the second logical groove has been seted up on the second core, be formed with the metal level that is used as local metallization bordure on the inner wall that the second led to the groove, the third logical groove has been seted up on the non-mobile PP layer of second, first blind groove, first logical groove, second logical groove, third logical groove, second blind groove position set up correspondingly, first non-mobile PP layer, first non-mobile PP, And after the second core plate, the second non-flowable PP layer and the third core plate are pressed into a whole, the first blind groove, the first through groove, the second through groove, the third through groove and the second blind groove are communicated to form an internal blind groove cavity.

Preferably, a first laser cutting groove communicated with the first blind groove is formed in a part, corresponding to the first blind groove, of the first core plate through laser control deep cutting.

Preferably, a second laser cutting groove communicated with the second blind groove is formed in a part, corresponding to the second blind groove, of the third core plate through laser control deep cutting.

The invention also provides a local metallization edge covering processing technology of the circuit board, which comprises the following steps:

step 1, a first core plate, a first non-flowing PP layer, a second core plate, a second non-flowing PP layer and a third core plate are prepared in advance, wherein,

the first core plate and the third core plate comprise the following manufacturing steps 11-13:

step 11, internal light imaging 1: adhering a dry film on the board surface under certain temperature and pressure, aligning the dry film with a negative plate, irradiating the dry film on an exposure machine by using ultraviolet light to react the dry film which is not shielded by the negative plate to form a required circuit pattern on the board surface, dissolving the film which is not irradiated by the light under the action of a developing solution through a developing section to expose the area needing etching on the first side, and protecting the copper surface on the second side by using the dry film;

step 12, inner layer etching: copper and copper ions react in an etching cylinder to produce cuprous copper, the circuit on the first side is manufactured, and then the film is dissolved under the action of alkali liquor in a film stripping cylinder to expose the required circuit;

step 13, laser pre-control deep cutting: carrying out laser pre-depth control cutting from the first side according to design data, wherein the width of a pre-depth control groove is 0.15mm, the depth is 0.2mm, the depth tolerance is +/-0.05 mm, and the residual thickness is guaranteed to be more than or equal to 0.15mm, so that cutting penetration is prevented, and a 'Chinese character hui' shaped groove is formed;

the second core plate comprises the following manufacturing steps 21-26:

step 21, milling a metal slot: carrying out plate milling machine processing on the plate by using a 0.6mm milling cutter, and milling a long groove at the position of the edge covering;

step 22, copper/plate deposition: thickening the copper at the position and the surface of the edge covering by 5-8um in a whole-plate electroplating mode, and connecting the edge covering with the copper of the second core plate;

step 23, external light imaging: adhering a dry film on the board surface under certain temperature and pressure, aligning the dry film with a negative film, irradiating the dry film on an exposure machine by using ultraviolet light to react the dry film which is not shielded by the negative film to form a required circuit pattern on the board surface, dissolving the film which is not irradiated by the light under the action of a developing solution through a developing section, and exposing a region which needs to be plated with copper and tin;

step 24, pattern electroplating: plating a metal copper layer and a tin layer for anti-etching protection on the conductive area of the plate;

step 25, milling a half hole: milling the plate by using a 0.6mm milling cutter on the plate, and milling the positions of two ends, which do not need metal wrapping edges;

step 26, outer layer etching: under the action of alkali liquor, removing the film to expose the copper surface to be etched, reacting copper with copper ions in an etching cylinder to produce cuprous to achieve the etching effect, and removing a tin coating layer to expose the copper surface of the circuit bonding pad due to the reaction of nitric acid with the tin surface in a tin stripping cylinder;

performing plate milling machine processing on the first non-flowable PP layer and the second non-flowable PP layer by using a 0.75mm milling cutter to mill a first through groove and a third through groove with the width of 0.75 mm;

step 2, laminating: browning a first core plate, a second core plate and a third core plate, then stacking a first non-flowable PP layer and a second non-flowable PP layer, riveting the first non-flowable PP layer and the second non-flowable PP layer by using pipe position nails, filling the circuit and the base material by resin flow of a prepreg under the action of certain temperature and pressure, and curing when the temperature reaches a certain degree to bond the layers together to form a blind groove structure;

step 3, drilling, copper deposition/plate plating, external light imaging 1, pattern electroplating, outer layer etching and solder resistance/characters are carried out on the plate body formed in the step 2;

step 4, laser cutting: and (4) carrying out laser cutting on the upper surface and the lower surface of the plate body formed in the step (3), wherein the groove width is 0.15mm, and the depth tolerance is +/-0.05 mm, and cutting off the residual thickness of the pre-controlled depth.

Preferably, the method further comprises the following steps: and 5: gold precipitation: and depositing a metallic nickel layer and a gold layer on the copper surface through chemical displacement reaction.

By adopting the technical scheme, all layers do not need to be subjected to metallization edge covering in advance, and then depth control milling is carried out to mill off redundant layers of metallization edge covering and then etching is carried out, so that the problems that the metallization edge covering layer is damaged by milling depth and the size and quality of a unit are influenced due to depth control milling are solved, and mass production can be realized.

Drawings

FIG. 1 schematically illustrates a laminate structure of the present invention;

FIG. 2 schematically illustrates a schematic representation of the location of a laser cut groove;

fig. 3 schematically shows a schematic structural view of the final product of the present invention.

Reference numbers in the figures: 1. a first core board; 2. a first non-flowing PP layer; 3. a second core board; 4. a second non-flowing PP layer; 5. a third core board; 6. a conductive metal strip; 7. a first blind slot; 8. a second blind slot; 9. a first through groove; 10. a second through groove; 11. a metal layer; 12. a third through groove; 13. a first laser cutting groove; 14. a second laser cutting groove; 15. uncovering the area; 16. and (4) a green oil layer.

Detailed Description

The following detailed description of embodiments of the invention, but the invention can be practiced in many different ways, as defined and covered by the claims.

As an aspect of the present invention, there is provided a circuit board partial metallization edge-wrapped lamination structure, including: first core 1, first fluidity PP layer 2, second core 3, second fluidity PP layer 4 and third core 5 that from top to bottom set gradually, all be formed with conductive metal strip 6 on first core 1, second core 3 and the third core 5, the orientation of first core 1 the second core 3 one side is formed with first blind groove 7 on the surface, the orientation of third core 5 the second core 3 one side is formed with second blind groove 8 on the surface, first through groove 9 has been seted up on first fluidity PP layer 2, second through groove 10 has been seted up on second core 3, be formed with on the inner wall that the second led to groove 10 and be used as the bordure metal level 11 of local metallization, third through groove 12 has been seted up on the second fluidity PP layer 4, first blind groove 7, first through groove 9, second through groove 10, third through groove 12, The second blind grooves 8 are correspondingly arranged, and after the first core plate 1, the first non-flowable PP layer 2, the second core plate 3, the second non-flowable PP layer 4 and the third core plate 5 are pressed into a whole, the first blind grooves 7, the first through grooves 9, the second through grooves 10, the third through grooves 12 and the second blind grooves 8 are communicated to form an internal blind groove cavity.

Preferably, a first laser cutting groove 13 communicated with the first blind groove 7 is formed in the part, corresponding to the first blind groove 7, of the first core plate 1 through laser controlled deep cutting.

Preferably, a second laser cutting groove 14 communicated with the second blind groove 8 is formed in the third core plate 5 at a position corresponding to the second blind groove 8 by laser controlled deep cutting.

In the above technical solution, the first core plate 1, the first no-flow PP layer 2, the second core plate 3, the second no-flow PP layer 4, and the third core plate 5, and the conductive metal strips 6, the first blind grooves 7, the second blind grooves 8, and the first through grooves 9 thereon; the second through grooves 10, the metal layer 11 and the third through grooves 12 are all arranged on corresponding plates or layers which are manufactured in advance, then the first core plate 1, the first non-flowing PP layer 2, the second core plate 3, the second non-flowing PP layer 4 and the third core plate 5 are laminated and combined into a whole, and an inner blind groove cavity is formed in the inner blind groove cavity.

Therefore, in the subsequent processing process, the first blind groove 7, the second blind groove 8 and the first through groove 9 can be formed; the second through grooves 10 and the third through grooves 12 are cut, so that the right side of the metal layer 11 in fig. 1 is removed, and a final product is obtained.

In the manufacturing process, a first core plate 1, a second core plate 3 and a third core plate 5 are browned, then a first non-flowing PP layer 2 and a second non-flowing PP layer 4 (non-flowing prepregs) are stacked, after the first non-flowing PP layer and the second non-flowing PP layer are riveted by pipe position nails, under the action of certain temperature and pressure, resin flowing of the prepregs is carried out to fill circuits and base materials, when the temperature reaches a certain degree, solidification occurs, the layers are bonded together to form the structure shown in the figure 1, and meanwhile, the structure of an internal blind groove cavity is formed.

In one embodiment, the cutting is laser cutting, so that the first laser cutting groove 13 and the second laser cutting groove 14 are formed, and the pre-controlled depth residual thickness is removed.

By adopting the technical scheme, all layers do not need to be subjected to metallization edge covering in advance, and then depth control milling is carried out to mill off redundant layers of metallization edge covering and then etching is carried out, so that the problems that the metallization edge covering layer is damaged by milling depth and the size and quality of a unit are influenced due to depth control milling are solved, and mass production can be realized.

The invention also provides a local metallization edge covering processing technology of the circuit board, which comprises the following steps:

step 1, a first core plate 1, a first no-flow PP layer 2, a second core plate 3, a second no-flow PP layer 4 and a third core plate 5 are prepared in advance, wherein,

the first core plate 1 and the third core plate 5 comprise the following manufacturing steps 11-13:

step 11, internal light imaging 1: adhering a dry film on the board surface under certain temperature and pressure, aligning the dry film with a negative plate, irradiating the dry film on an exposure machine by using ultraviolet light to react the dry film which is not shielded by the negative plate to form a required circuit pattern on the board surface, dissolving the film which is not irradiated by the light under the action of a developing solution through a developing section to expose the area needing etching on the first side, and protecting the copper surface on the second side by using the dry film;

step 12, inner layer etching: copper and copper ions react in an etching cylinder to produce cuprous copper, the circuit on the first side is manufactured, and then the film is dissolved under the action of alkali liquor in a film stripping cylinder to expose the required circuit;

step 13, laser pre-control deep cutting: carrying out laser pre-depth control cutting from the first side according to design data, wherein the width of a pre-depth control groove is 0.15mm, the depth is 0.2mm, the depth tolerance is +/-0.05 mm, and the residual thickness is guaranteed to be more than or equal to 0.15mm, so that cutting penetration is prevented, and a 'Chinese character hui' shaped groove is formed;

the second core plate 3 comprises the following manufacturing steps 21-26:

step 21, milling a metal slot containing a covered edge: carrying out plate milling machine processing on the plate by using a 0.6mm milling cutter, and milling a long groove at the position of the edge covering;

step 22, copper/plate deposition: thickening the copper at the position and the surface of the edge covering by 5-8um in a whole-plate electroplating mode, and connecting the edge covering with the copper of the second core plate 3;

step 23, external light imaging: adhering a dry film on the board surface under certain temperature and pressure, aligning the dry film with a negative film, irradiating the dry film on an exposure machine by using ultraviolet light to react the dry film which is not shielded by the negative film to form a required circuit pattern on the board surface, dissolving the film which is not irradiated by the light under the action of a developing solution through a developing section, and exposing a region which needs to be plated with copper and tin;

step 24, pattern electroplating: plating a metal copper layer and a tin layer for anti-etching protection on the conductive area of the plate;

step 25, milling a half hole: milling the plate by using a 0.6mm milling cutter on the plate, and milling the positions of two ends, which do not need metal wrapping edges;

step 26, outer layer etching: under the action of alkali liquor, removing the film to expose the copper surface to be etched, reacting copper with copper ions in an etching cylinder to produce cuprous to achieve the etching effect, and removing a tin coating layer to expose the copper surface of the circuit bonding pad due to the reaction of nitric acid with the tin surface in a tin stripping cylinder;

performing plate milling machine processing on the first non-flowable PP layer 2 and the second non-flowable PP layer 4 by using a 0.75mm milling cutter to mill a first through groove 9 and a third through groove 12 with the width of 0.75 mm;

step 2, laminating: browning a first core plate 1, a second core plate 3 and a third core plate 5 layers of core plates, then stacking a first non-flowable PP layer 2 and a second non-flowable PP layer 4, riveting by using pipe position nails, filling a circuit and a base material through resin flow of a prepreg under the action of certain temperature and pressure, and when the temperature reaches a certain degree, curing to bond the layers together and simultaneously form a blind groove structure;

step 3, drilling, copper deposition/plate plating, external light imaging 1, pattern electroplating, outer layer etching and solder resistance/characters are carried out on the plate body formed in the step 2; wherein the content of the first and second substances,

in the drilling step, according to the requirement of a customer, a drilling machine is used for machining on a plate, and preparation is made for facilitating the conduction of the inner layer and the outer layer in the subsequent process;

in the step of copper deposition/plate plating, the drill hole dirt in the hole is removed through the glue removing slag, the hole is cleaned, then the glue is activated, colloidal palladium is adsorbed on the surface and in the hole, and an oxidation-reduction reaction is carried out in a copper deposition cylinder, so that a copper layer is formed. Then, thickening the hole copper and the surface copper by 5-8um in a whole-plate electroplating mode; the hole is connected to the outer layer of copper.

In the step 1 of external light imaging, a dry film is pasted on a plate surface under certain temperature and pressure, then a negative plate is used for contraposition, finally the dry film which is not shielded by the negative plate is made to react by utilizing the irradiation of ultraviolet light on an exposure machine, a required circuit pattern is formed on the plate surface, then the film which is not irradiated by the light is dissolved under the action of a developing solution through a developing section, and an area which needs to be plated with copper and tin is exposed.

In the step of pattern electroplating, the board surface is cleaned through pretreatment, copper ions and tin ions are dissolved out from the anode of a copper plating and tin plating cylinder, the copper ions and the tin ions move to the cathode under the action of an electric field to obtain electrons, and a metal copper layer and a tin layer for anti-etching protection are plated on a conductive area on the board.

In the outer layer etching step, under the action of alkali liquor, the film is removed to expose the copper surface to be etched, copper and copper ions react in an etching cylinder to produce cuprous, the etching effect is achieved, and a tin coating layer is removed in a tin stripping cylinder due to the reaction of nitric acid and the tin surface, so that the copper surface of the circuit bonding pad is exposed.

In the step of solder mask/character, solder mask: solder resist mud is printed on the board surface by a screen printing net, volatilization is removed by pre-drying to form a semi-cured film layer, the solder resist film is subjected to cross-linking reaction in the illuminated place through counterpoint exposure, and the unexposed place is developed under the action of alkali liquor. And (4) completely curing the solder resist at high temperature and attaching the solder resist to the board surface. Character: the manufacturing method is similar to that of the solder resist.

Step 4, laser cutting: and (4) carrying out laser cutting on the upper surface and the lower surface of the plate body formed in the step (3), wherein the groove width is 0.15mm, and the depth tolerance is +/-0.05 mm, and cutting off the residual thickness of the pre-controlled depth.

Preferably, the method further comprises the following steps: and 5: gold precipitation: and depositing a metallic nickel layer and a gold layer on the copper surface through chemical displacement reaction.

In the technical scheme, the second core plate 3 with the local-level metallization edge is manufactured firstly, then the second core plate is overlapped with the first core plate 1 and the third core plate 5 which are subjected to laser cutting and pre-depth control grooving and the non-flowing PP subjected to grooving, a blind groove structure is formed by pressing, and then the second core plate is manufactured by the processes of drilling, electrolytic copper deposition, external light imaging, outer layer etching, resistance welding, character cutting, laser cutting, gold deposition and the like.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (5)

1. The utility model provides a local metallization bordure lamination of circuit board which characterized in that includes: a first core plate (1), a first non-flowing PP layer (2), a second core plate (3), a second non-flowing PP layer (4) and a third core plate (5) which are sequentially arranged from top to bottom, wherein conductive metal strips (6) are formed on the first core plate (1), the second core plate (3) and the third core plate (5), a first blind groove (7) is formed on the surface of one side of the first core plate (1) facing the second core plate (3), a second blind groove (8) is formed on the surface of one side of the third core plate (5) facing the second core plate (3), a first through groove (9) is formed on the first non-flowing PP layer (2), a second through groove (10) is formed on the second core plate (3), a metal layer (11) used as a local metallization edge covering is formed on the inner wall of the second through groove (10), a third through groove (12) is formed on the second non-flowing PP layer (4), the first blind groove (7), the first through groove (9), the second through groove (10), the third through groove (12) and the second blind groove (8) are correspondingly arranged, the first core plate (1), the first non-flowable PP layer (2), the second core plate (3), the second non-flowable PP layer (4) and the third core plate (5) are pressed into a whole, and the first blind groove (7), the first through groove (9), the second through groove (10), the third through groove (12) and the second blind groove (8) are communicated to form an internal blind groove cavity.

2. The circuit board partial metallization edge-covering laminated structure according to claim 1, characterized in that a first laser-cut groove (13) communicated with the first blind groove (7) is formed on the first core plate (1) corresponding to the first blind groove (7) by means of laser controlled deep cutting.

3. The circuit board partial metallization edge-covering laminated structure according to claim 1, characterized in that a part of the third core plate (5) corresponding to the second blind groove (8) is formed with a second laser-cut groove (14) communicating with the second blind groove (8) by means of laser controlled deep cutting.

4. A local metallization edge covering processing technology of a circuit board is characterized by comprising the following steps:

step 1, a first core plate (1), a first non-flowing PP layer (2), a second core plate (3), a second non-flowing PP layer (4) and a third core plate (5) which are arranged from top to bottom are prepared in advance, wherein,

the first core plate (1) and the third core plate (5) comprise the following manufacturing steps 11-13:

step 11, internal light imaging 1: adhering a dry film on the board surface under certain temperature and pressure, aligning the dry film with a negative plate, irradiating the dry film on an exposure machine by using ultraviolet light to react the dry film which is not shielded by the negative plate to form a required circuit pattern on the board surface, dissolving the film which is not irradiated by the light under the action of a developing solution through a developing section to expose the area needing etching on the first side, and protecting the copper surface on the second side by using the dry film;

step 12, inner layer etching: copper and copper ions react in an etching cylinder to produce cuprous copper, the circuit on the first side is manufactured, and then the film is dissolved under the action of alkali liquor in a film stripping cylinder to expose the required circuit;

step 13, laser pre-control deep cutting: carrying out laser pre-depth control cutting from the first side according to design data, wherein the width of a pre-depth control groove is 0.15mm, the depth is 0.2mm, the depth tolerance is +/-0.05 mm, and the residual thickness is guaranteed to be more than or equal to 0.15mm, so that cutting penetration is prevented, and a 'Chinese character hui' shaped groove is formed;

the second core plate (3) comprises the following manufacturing steps 21-26:

step 21, milling a metal slot (including a wrapping edge): carrying out plate milling machine processing on the plate by using a 0.6mm milling cutter, and milling a long groove at the position of the edge covering;

step 22, copper/plate deposition: thickening the copper at the position and the surface of the edge covering by 5-8um in a whole-plate electroplating mode, and connecting the edge covering with the copper of the second core plate (3);

step 23, external light imaging: adhering a dry film on the board surface under certain temperature and pressure, aligning the dry film with a negative film, irradiating the dry film on an exposure machine by using ultraviolet light to react the dry film which is not shielded by the negative film to form a required circuit pattern on the board surface, dissolving the film which is not irradiated by the light under the action of a developing solution through a developing section, and exposing a region which needs to be plated with copper and tin;

step 24, pattern electroplating: plating a metal copper layer and a tin layer for anti-etching protection on the conductive area of the plate;

step 25, milling a half hole: milling the plate by using a 0.6mm milling cutter on the plate, and milling the positions of two ends, which do not need metal wrapping edges;

step 26, outer layer etching: under the action of alkali liquor, removing the film to expose the copper surface to be etched, reacting copper with copper ions in an etching cylinder to produce cuprous to achieve the etching effect, and removing a tin coating layer to expose the copper surface of the circuit bonding pad due to the reaction of nitric acid with the tin surface in a tin stripping cylinder;

performing plate milling machine machining on the first non-flowable PP layer (2) and the second non-flowable PP layer (4) by using a 0.75mm milling cutter to mill a first through groove (9) and a third through groove (12) with the width of 0.75 mm;

step 2, laminating: brownification is carried out on the core plates of the first core plate (1), the second core plate (3) and the third core plate (5), then the first non-flowable PP layer (2) and the second non-flowable PP layer (4) are stacked, after being riveted by pipe position nails, the circuit and the base material are filled through resin flow of the prepreg under the action of certain temperature and pressure, when the temperature reaches a certain degree, solidification occurs, the layers are bonded together, and meanwhile, a structure of a blind groove is formed;

step 3, drilling, copper deposition/plate plating, external light imaging 1, pattern electroplating, outer layer etching and solder resistance/characters are carried out on the plate body formed in the step 2;

step 4, laser cutting: and (4) carrying out laser cutting on the upper surface and the lower surface of the plate body formed in the step (3), wherein the groove width is 0.15mm, and the depth tolerance is +/-0.05 mm, and cutting off the residual thickness of the pre-controlled depth.

5. The local metallization edge covering processing technology for the circuit board according to claim 4, characterized by further comprising:

and 5: gold precipitation: and depositing a metallic nickel layer and a gold layer on the copper surface through chemical displacement reaction.

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