Manufacturing method of pseudo large-current-carrying thick copper flexible circuit board

Abstract

The invention discloses a manufacturing method of a pseudo large-current-carrying thick copper flexible circuit board, which comprises the following steps of: taking an insulating material plate to attach an adhesive layer, taking a thick copper layer, attaching the thick copper layer to one surface of the adhesive layer, performing primary pattern processing on the thick copper layer, etching off partial thickness, manufacturing a resin pattern on the etched pattern, electroplating the copper layer, and attaching a dry film. Performing second pattern processing according to the pattern of the first pattern processing, taking a first cover film, attaching the first cover film to one side of the second pattern processing, removing the auxiliary layer, exposing the copper layer which is not etched for the first time, performing third pattern processing, taking a second cover film, attaching the second cover film to one side of the third pattern processing, and removing the auxiliary layer to expose the copper layer which is not etched for the second time; forming a pseudo large-current-carrying thick copper flexible circuit board; the auxiliary layer is used for supporting the thick copper layer, the addition manufacturing mode of the thick copper circuit pattern is adopted, the resin pattern ensures that the board surface is flat, the first covering film and the second covering film are attached to form the false flexible circuit board structure, and the effect of the thick copper circuit pattern formed in the whole machining process is good.

Description

Technical Field

[0001] The invention relates to the field of circuit board processing, and in particular to a method for manufacturing a pseudo high-current-carrying thick copper flexible circuit board. Background Art

[0002] For some power modules such as smart connected car charging piles, thick copper circuit boards with large current carrying capacity are required. For circuit boards with ultra-high current carrying capacity, the copper thickness is generally ≥105μm, or even ultra-thick copper ≥245μm.

[0003] When thick copper circuit boards are manufactured, due to the excessive thickness of the copper, the etching process of the pattern processing is prone to excessive side etching of the circuit and too small etching factor, resulting in the circuit pattern being narrow at the top and wide at the bottom, affecting the current carrying capacity and easily causing problems such as short circuits.

[0004] At present, the etching problem of thick copper circuits is generally solved by adjusting the etching method, such as adjusting the etching spray mode, or improving the characteristic performance of the etching solution.

[0005] However, whether adjusting the etching method or improving the characteristic performance of the etching solution, the effect of increasing the etching factor is limited, and at the same time it will be accompanied by problems such as increased use of the solution and increased pollution.

[0006] Based on the above background and problems, a partial manufacturing method using a flexible circuit board is provided from the perspective of processing methods, so as to form a manufacturing method that can effectively improve the processing effect of a large current-carrying thick copper circuit board. Summary of the invention

[0007] Aiming at the problem of too small etching factor in the pattern production of thick copper and large current-carrying circuit boards in the prior art, the present invention provides a production method for a pseudo large current-carrying thick copper flexible circuit board partially with the help of flexible circuit board processing technology, wherein the circuit board is designed with a molding line, the area within the range of the molding line is an effective area, and the area outside the range of the molding line is an invalid area.

[0008] The production method comprises the following steps: S10: taking an insulating material plate of the same size as the circuit board, and attaching a glue layer to one side thereof corresponding to the ineffective area to form an auxiliary layer; S20: taking a thick copper layer, attaching it to one side of the adhesive layer of the auxiliary layer, and sequentially performing dry film attaching, exposure, development, and first etching processing on the thick copper layer to form a first half-etched pattern, wherein the first half-etching processing is to etch away a portion of the thickness of the thick copper layer, and the unetched thick copper layer is the first reserved half copper, and the first half-etched plate is formed as a whole; S30: screen printing resin, curing, grinding, and electroplating copper layer processing are performed on one side of the first half-etched pattern 210 of the first half-etched board in sequence, and then dry film is applied to the electroplated copper layer, and exposure, development, and second etching processing are performed in sequence according to the pattern distribution of the first half-etched pattern to form a second half-etched pattern, thereby forming a second half-etched board as a whole; S40: According to the same manufacturing method as the step S30, a plurality of first-side etching patterns that are identical to the second half-etched pattern and are stacked in sequence are manufactured on the second half-etched plate to form a first-side pattern plate; S50: taking a first covering film, attaching the first covering film to the first side of the first pattern plate where the first side is etched with the pattern, and removing the auxiliary layer to expose the first reserved half copper, thereby forming a first covering film pattern plate; S60: the first retained half copper is subjected to dry film application, exposure, development, and third etching processing in sequence to form a third half etching pattern; a fourth half etching pattern identical to the third half etching pattern and stacked is produced on the third half etching pattern according to the same production method as the step of S30, and a plurality of stacked second side etching patterns are produced; a second covering film is taken, and the second covering film is attached to one side of the second side etching pattern to form the pseudo high current carrying thick copper flexible circuit board as a whole.

[0009] Optionally, take the insulating material board with the same size as the circuit board, take the covering film layer, attach the covering film layer to the surface of the insulating material board, and attach the glue layer to the surface of the covering film layer corresponding to the invalid area to form the auxiliary layer.

[0010] Optionally, the insulating material board is a FR-4 board, a PP board, a PET board or a PTFE board.

[0011] Optionally, the adhesive layer is acrylic adhesive or epoxy resin adhesive.

[0012] Optionally, the adhesive layer is attached inwardly along the edge of the circuit board, and the attachment width of the adhesive layer is smaller than the width from the edge to the molding line.

[0013] Optionally, the second half-etched plate is formed, and then, a side of the second half-etched pattern is subjected to sequential screen printing of resin, curing, and grinding to form the second half-etched plate as a whole.

[0014] Optionally, the resin is solder resist ink or via plugging resin.

[0015] Optionally, the auxiliary layer is removed by milling the circuit board along the edge of the glue layer extending into the invalid area to remove the auxiliary layer; or, the auxiliary layer is removed by laser ablating the insulating material plate along the contour of the glue layer, removing the insulating material plate, and grinding the glue layer.

[0016] Optionally, the width of the second half-etched pattern is smaller than that of the first half-etched pattern on one side. The widths of the first surface etching patterns decrease sequentially from the first half etching pattern outward.

[0017] Optionally, the width of the fourth half-etched pattern is smaller than that of the third half-etched pattern on one side. The widths of the second-side etching patterns decrease sequentially from the third half-etching pattern outward.

[0018] The technical solution of the present invention provides good support for the first side circuit pattern processing of the thick copper layer by using the auxiliary layer to support the thick copper layer, and using the adhesive layer to form a sealed adhesion between the thick copper layer and the auxiliary layer, and provides a thick copper layer of the base layer, adopts a half-etching method to form a first half-etched pattern, and then performs an additive method of electroplating the copper layer to form a first half-etched pattern, and then uses an additive method to form a thick copper circuit pattern of a laminated structure, and the second side is made in the same way, and a method of using a screen printing resin to form a resin pattern is used. On the one hand, the height difference of the circuit gap is filled, and on the other hand, a base for electroplating is provided for the electroplated copper layer to ensure the reliability of the circuit pattern production, and a method of attaching a first covering film of a flexible circuit board is used to provide a support basis for the circuit pattern production of the second side, and the method of using a rigid board to make a solder mask pattern is prevented. The problem that it is difficult to provide a basis for the second side processing is prevented. The attachment of the first covering film and the second covering film enables the circuit board to form a pseudo-flexible circuit board structure, and further improves the overall structural reliability of the circuit board; the overall processing process forms a front-to-back matching process production method, which provides an effective and feasible production method for the processing of thick copper circuit boards. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0020] Figure 1 The main process flow chart of the embodiment of the present invention is included; Figure 2is a schematic diagram of the cross-sectional structure of the auxiliary layer of this embodiment; Figure 3 is a schematic diagram of the cross-sectional structure of another auxiliary layer of this embodiment; Figure 4 is a schematic cross-sectional view of a first half-etched plate of the present embodiment; Figure 5 is a schematic cross-sectional view of a first resin graphic plate of the present embodiment; Figure 6 is a schematic cross-sectional view of the second half-etched plate of this embodiment; Figure 7 is a cross-sectional schematic diagram of a first cover film attached plate of this embodiment; Figure 8 is a cross-sectional schematic diagram of another first cover film attached plate of the present embodiment; Fig. 9 is a cross-sectional schematic diagram of a first cover film graphic plate of the present embodiment; Fig.10 is a schematic cross-sectional view of a third half-etched plate of this embodiment; Fig.11 is a schematic cross-sectional view of a pseudo high current carrying thick copper flexible circuit board of this embodiment; Fig.12 This is a physical picture of the pseudo high current carrying thick copper flexible circuit board of this embodiment.

[0021] Description of Figure Numbers:

[0022] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, inside, outside...) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0025] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0026] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0027] See also Figure 1 ; Figure 1 The main process flow chart included in the embodiment of the present invention.

[0028] The method for manufacturing a pseudo high current carrying thick copper flexible circuit board according to an embodiment of the present invention comprises: Figure 1 The main production process is described in detail step by step as follows.

[0029] See also Figure 2 and Figure 3 ; Figure 2 is a schematic diagram of the cross-sectional structure of the auxiliary layer of this embodiment; Figure 3 It is a schematic diagram of the cross-sectional structure of another auxiliary layer of this embodiment.

[0030] The pseudo high current carrying thick copper flexible circuit board of the embodiment of the present invention is designed with a forming line 100, the area within the range of the forming line is the effective area, and the area outside the range is the ineffective area.

[0031] Step S10: Take an insulating material plate 100 of the same size as the circuit board, and attach a glue layer 120 to one side thereof corresponding to the ineffective area to form an auxiliary layer 10 (such as Figure 2 as shown).

[0032] Since the present embodiment adopts a single-layer thick copper layer 200 to make the circuit pattern, the single-layer thick copper layer 200 needs to be supported, so an auxiliary layer 10 is made as a support, and the auxiliary layer 10 is an auxiliary structure in the processing process, rather than a structure retained in the finished circuit board. Therefore, the auxiliary layer 10 and the thick copper layer 200 can be adhered to each other through a high-temperature and high-pressure pressing process by using the glue layer 120, and it can ensure that the area without the glue layer 120 is not adhered, which is convenient for subsequent removal.

[0033] In this embodiment, an insulating material plate 100 having the same size as the circuit board is taken, and a covering film layer 130 is taken, the covering film layer 130 is attached to the surface of the insulating material plate 100, and the adhesive layer 120 is attached to the surface of the covering film layer 130 corresponding to the inactive area to form an auxiliary layer 10A (such as Figure 3 as shown).

[0034] The covering film layer 130 is generally made of polyimide, which has good inertness. Compared with the good adhesion effect between the thick copper layer 200 and the adhesive layer 120 under lamination conditions, the bonding force between polyimide and the thick copper layer 200 is poor, forming a release effect, which can facilitate the subsequent removal of the effective area and the auxiliary layer 10A.

[0035] In this embodiment, the insulating material plate 110 is a FR-4 plate, a PP plate, a PET plate or a PTFE plate. Preferably, the thickness of the insulating material plate 110 is 1.0 mm to 3.0 mm, preferably 1.6 mm or 2.0 mm.

[0036] Generally, an FR-4 board having similar performance to the insulating medium layer material of the circuit board itself is used as the insulating material board 110 . Other materials may also be used when the processing accuracy is not strictly required.

[0037] In this embodiment, the adhesive layer 120 is acrylic adhesive or epoxy resin adhesive; both adhesive layers have relatively good bonding strength with the thick copper layer 200 .

[0038] In this embodiment, the adhesive layer 120 is attached inwardly along the edge of the circuit board, and the attachment width of the adhesive layer 120 is smaller than the width from the edge to the molding line 100 .

[0039] The width of the adhesive layer 120 must completely cover the ineffective area, so as to effectively bond the auxiliary layer 10 or the auxiliary layer 10A and the thick copper layer 200 tightly and firmly at the edges, prevent problems such as liquid seepage during subsequent processing, and facilitate subsequent complete separation from the effective area.

[0040] Preferably, the tool patterns distributed in the invalid area are arranged in the area corresponding to the non-glue layer 120 covering area to prevent the tool patterns from being removed after the auxiliary layer 10A is removed later. However, the tool holes may not be arranged first, and the tool holes may be made after the auxiliary layer 10 or the auxiliary layer 10A is removed later to prevent the problem of the glue layer 120 being broken and the drug seeping in due to the making of the tool holes.

[0041] See also Figure 4 ; Figure 4 Schematic diagram of the cross section of the first half-etched plate of this embodiment.

[0042] Step S20: Take a thick copper layer 200, which is generally ≥105 μm thick, and attach it to one side of the adhesive layer 120 of the auxiliary layer 10. The thick copper layer 200 is subjected to dry film application, exposure, development, and first etching in sequence to form a first half-etched pattern 210. The first half-etching process is to etch away a portion of the thick copper layer 200. The unetched thick copper layer 200 is the first reserved half copper 220, and the first half-etched plate 20 (such as Figure 4 as shown).

[0043] This embodiment adopts an additive pattern stacking method of “half etching + half etching + …” to form the final high-precision thick copper layer pattern; the thickness of the first half-etched pattern 210 is 1 / 3 to 3 / 5 of the thick copper layer 200.

[0044] See also Figure 5 and Figure 6 ; Figure 5 is a schematic cross-sectional view of a first resin graphic plate of the present embodiment; Figure 6 Schematic cross-sectional view of the second half-etched plate of this embodiment.

[0045] Step S30: The first half-etched pattern 210 of the first half-etched plate 20 is subjected to sequential screen printing of resin, curing, and polishing to form a first resin layer 310, thereby forming a first resin pattern plate 30 (such as Figure 5 As shown), a copper layer is electroplated, and a dry film is attached to the electroplated copper layer, and exposure, development, and second etching are performed in sequence according to the pattern distribution of the first half-etched pattern 210 to form a second half-etched pattern 410, and a second half-etched plate 40 (as shown) is formed as a whole. Figure 6 as shown).

[0046] By screen printing resin and making resin patterns, the gaps in the first half-etched pattern 210 are filled, the line height difference of the thick copper layer is reduced, and a plating basis is provided for subsequent copper electroplating, and a basis is provided for the subsequent attachment of the first covering film 610 and the second covering film 830 to attach and fill the line gaps; the screen-printed resin can be screen-printed using a dot screen, and the resin is only screen-printed in the gaps between the first half-etched patterns 210. The thickness of the first resin layer 310 is less than or equal to the thickness of the first half-etched pattern 210. When screen printing, a small amount of resin can be screen-printed, and it is not necessary to screen-print to the same thickness as the first half-etched pattern 210, otherwise more resin will overflow to the surface of the first half-etched pattern 210, causing difficulty in polishing.

[0047] The thickness of the electroplated copper layer is determined according to the number of times the required finished copper thickness is split. Generally, the electroplating thickness is 25 μm to 50 μm, preferably 35 μm. The electroplated copper layer is etched to form a second half-etched pattern 410 stacked on the surface of the first half-etched pattern 210, thereby forming an overall thick copper circuit pattern.

[0048] Step S40: According to the same manufacturing method as step S30, a plurality of first-side etching patterns (not shown in the drawings) which are identical to the second half-etched pattern 410 and stacked in sequence are formed on the second half-etched plate 40 to form a first-side pattern plate.

[0049] If it is necessary to continue to form a laminated circuit pattern after the second half-etched pattern 410 is produced, further lamination processing is performed in accordance with the above-mentioned method, that is, one side of the second half-etched pattern 410 of the second half-etched plate 40 is successively screen-printed with resin, cured, and polished to form a laminated resin layer, and then a copper layer is electroplated and a dry film is attached, and exposure, development, and etching processing are performed in sequence according to the pattern distribution of the second half-etched pattern 410 to form a laminated etching pattern.

[0050] In this embodiment, the width of the second half-etched pattern 410 is smaller than that of the first half-etched pattern 210 on one side, and the widths of the first side etched patterns decrease from the first half-etched pattern 210 outwards.

[0051] Due to the influence of the processing on the expansion and contraction of the plate, and the error of the exposure of the copper layer of each stacking, there may be a problem of deviation between the second half-etched pattern 410 and the first half-etched pattern 210. The stacking method with decreasing width is conducive to eliminating the processing deviation. Generally, the width is reduced successively to a single-side size of 5μm to 10μm.

[0052] See also Figure 7 , Figure 8 and Fig. 9 ; Figure 7 is a cross-sectional schematic diagram of a first cover film attached plate of this embodiment; Figure 8 is a cross-sectional schematic diagram of another first cover film attached plate of the present embodiment; Fig. 9 Schematic cross-sectional view of the first cover film graphic plate of this embodiment.

[0053] Step S50: Take the first cover film 510, and Figure 6 A first cover film 510 is attached to one side of the first etching pattern of the second half-etched plate 40 (as an example), forming a first cover film attached plate 50 (as an example Figure 7 As shown), and remove the auxiliary layer 10 to expose the first reserved half copper to form a first covering film pattern plate (as shown Fig. 9 as shown).

[0054] This embodiment adopts the processing method of attaching the first covering film 510. On the one hand, it can effectively fill the line gap of the second half-etched pattern 410 to form a good surface protection layer. On the other hand, the first covering film 510 can form a support for the board surface during the subsequent second surface processing, so that after removing the auxiliary layer 10, the board surface can still form a firm processable board surface with the first covering film 510 combined with the first resin layer 310 and the first half-etched pattern 210 and the second half-etched pattern 410.

[0055] In this embodiment, the second half-etched plate 40 is formed, and then: a second half-etched pattern 410 is subjected to a screen printing resin, curing, and grinding process in sequence to form a second half-etched plate 50A (such as Figure 8 as shown).

[0056] In one embodiment, a resin may be used to fill the line gaps of the second half-etched pattern 410 to reduce the height difference of the line gaps of the second half-etched pattern 410 .

[0057] In this embodiment, the resin is solder resist ink or plugging resin; both resin materials can form good filling, and the plugging resin has higher reliability than solder resist ink.

[0058] In this embodiment, the auxiliary layer 10 is removed by milling the circuit board along the edge of the adhesive layer 120 extending to the ineffective area to remove the auxiliary layer 10 .

[0059] Since the glue layer 120 covers the edge of the circuit board, the edge can be directly cut off to facilitate the removal of the auxiliary layer 10. That is, the board edge area corresponding to the glue layer 120 is the area for pre-enlarging the design size when designing the circuit board.

[0060] In one embodiment, the auxiliary layer 10 is removed by laser ablating the insulating material plate 110 along the contour of the adhesive layer 120 , removing the insulating material plate 110 , and grinding the adhesive layer 120 .

[0061] If the width of the adhesive layer 120 is narrow and the thickness of the insulating material plate 110 is thin, the adhesive layer 120 can be set in an invalid area between the effective plates of the panel. When removing it, laser ablation can be used to perform controlled depth ablation and then polishing to remove it.

[0062] See also Fig.10 , Fig.11 and Fig.12 ; Fig.10 is a schematic cross-sectional view of a third half-etched plate of this embodiment; Fig.11 is a schematic cross-sectional view of a pseudo high current carrying thick copper flexible circuit board of this embodiment; Fig.12 This is a physical picture of the pseudo high current carrying thick copper flexible circuit board of this embodiment.

[0063] Step S60: The first reserved half copper 220 is subjected to dry film lamination, exposure, development, and third etching processes in sequence to form a third half-etched pattern 710 (eg Fig.10 As shown in the figure, according to the same manufacturing method as step S30, a fourth half-etched pattern 810 identical to the third half-etched pattern and stacked is formed on the third half-etched pattern 710, and a plurality of stacked second-side etching patterns (not shown in the figure) are manufactured; a second covering film 830 is taken, and a second-side etching pattern (not shown in the figure) is etched on the second side. Fig.11 A second cover film 830 is attached to one side of the circuit board to form a pseudo high current carrying thick copper flexible circuit board 80 (such as Fig.11 as shown).

[0064] In this embodiment, the width of the fourth half-etched pattern is smaller than that of the third half-etched pattern on one side, and the widths of the plurality of second-side etched patterns decrease sequentially from the third half-etched pattern toward the outside.

[0065] The second surface is processed in the same manner as the first surface to form a laminated thick copper circuit pattern. It is worth noting that the application of the first covering film 510 and the second covering film 830 makes the circuit board form a pseudo-flexible circuit board.

[0066] It is worth noting that due to the actual design and processing of circuit boards, the actual structure diagram and the thickness of each layer, line width and other dimensions are all in the micron level. For example, the thickness of each layer is generally 5μm to 50μm. If the drawings in the specification are made according to the actual proportion, there will be a problem of unclear drawings. Therefore, in order to more clearly show the implementation process of the manufacturing method, the drawings of this embodiment are all schematic diagrams that enlarge the technical features, which do not represent the size of the actual structure diagram, nor do they represent enlarged views of the actual structure diagram in proportion.

[0067] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a pseudo high current carrying thick copper flexible circuit board, wherein the circuit board is designed with a forming line, the area within the range of the forming line is an effective area, and the area outside the range is an invalid area; It is characterized in that The production method comprises the following steps: S10: taking an insulating material plate of the same size as the circuit board, and attaching a glue layer to one side thereof corresponding to the ineffective area to form an auxiliary layer; S20: taking a thick copper layer, attaching it to one side of the adhesive layer of the auxiliary layer, and sequentially performing dry film attaching, exposure, development, and first etching processing on the thick copper layer to form a first half-etched pattern, wherein the first half-etching processing is to etch away a portion of the thickness of the thick copper layer, and the unetched thick copper layer is the first reserved half copper, and the first half-etched plate is formed as a whole; S30: performing screen printing resin, curing, grinding, and copper electroplating on one side of the first half-etched pattern of the first half-etched board, and then applying a dry film to the copper electroplating layer, and performing exposure, development, and second etching in sequence according to the pattern distribution of the first half-etched pattern to form a second half-etched pattern, thereby forming a second half-etched board as a whole; S40: According to the same manufacturing method as the step S30, a plurality of first-side etching patterns that are identical to the second half-etched pattern and are stacked in sequence are manufactured on the second half-etched plate to form a first-side pattern plate; S50: taking a first covering film, attaching the first covering film to the first side of the first pattern plate where the first side is etched with the pattern, and removing the auxiliary layer to expose the first reserved half copper, thereby forming a first covering film pattern plate; S60: the first retained half copper is subjected to dry film application, exposure, development, and third etching processing in sequence to form a third half etching pattern; a fourth half etching pattern identical to the third half etching pattern and stacked is produced on the third half etching pattern according to the same production method as the step of S30, and a plurality of stacked second side etching patterns are produced; a second covering film is taken, and the second covering film is attached to one side of the second side etching pattern to form the pseudo high current carrying thick copper flexible circuit board as a whole.

2. The method according to claim 1, characterized in that: The auxiliary layer is formed by taking the insulating material plate having the same size as the circuit board, A covering film layer is taken, attached to the surface of the insulating material plate, and a glue layer is attached to the surface of the covering film layer corresponding to the ineffective area to form the auxiliary layer.

3. The method according to claim 1 or 2, characterized in that: The insulating material board is a FR-4 board, a PP board, a PET board or a PTFE board.

4. The method according to claim 1 or 2, characterized in that: The adhesive layer is acrylic adhesive or epoxy resin adhesive.

5. The method according to claim 1 or 2, characterized in that: The adhesive layer is attached inwardly along the edge of the circuit board, and the attachment width of the adhesive layer is smaller than the width from the edge to the molding line.

6. The method according to claim 1, characterized in that: The second half-etched plate is formed, and then, The second half-etched plate is formed by sequentially printing resin, curing and grinding on one side of the second half-etched pattern.

7. The production method according to claim 1 or 6, characterized in that: The resin is solder resist ink or via plugging resin.

8. The method according to claim 1, characterized in that: Removing the auxiliary layer includes: milling the circuit board along the edge of the adhesive layer extending to the ineffective area to remove the auxiliary layer; Alternatively, the insulating material plate is laser ablated along the contour of the adhesive layer, the insulating material plate is removed, and the adhesive layer is polished.

9. The method according to claim 1, characterized in that: The width of the second half-etched pattern is smaller than that of the first half-etched pattern on one side, and the widths of the first surface etching patterns decrease in sequence from the first half-etched pattern outward.

10. The method according to claim 1, characterized in that: The width of the fourth half-etched pattern is smaller than that of the third half-etched pattern on one side, and the widths of a plurality of second-side etched patterns decrease in sequence from the third half-etched pattern outward.

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