Circuit board manufacturing structure and circuit board manufacturing method

Abstract

The present invention provides a circuit board manufacturing structure and a circuit board manufacturing method, the manufacturing method comprising: providing a substrate with a blind groove area defined, manufacturing a PI film bottom protective layer in the blind groove area based on laser cutting, laminating the substrate with a prepreg and copper foil, defining a uncovering area based on laser cutting, attaching a blue film to the uncovering area, and removing the uncovering blue film to obtain a blind groove. The present invention provides a novel method for manufacturing a blind groove in a PCB circuit board, based on the technical solution of the present invention, using a PI film as the bottom protective layer of the circuit graphic part, then laminating through a prepreg and a metal foil, and uncovering through a blue film, the residual glue in the blind groove manufacturing can be effectively reduced, and the method can be suitable for the production of circuit boards with small PCB sizes and high requirements for blind groove manufacturing precision.

Description

Technical Field

[0001] The invention belongs to the technical field of PCB circuit board manufacturing, and in particular relates to a circuit board manufacturing structure and a manufacturing method thereof. Background Art

[0002] In order to meet the demand for thinner electronic products / components, PCB blind slot technology came into being. Traditional electronic products / components are assembled on the surface of PCB boards, and the thickness of the finished product is determined by the superposition of the thickness of the PCB board and the electronic components. Blind slot PCB embeds the electronic components into the PCB board, thus effectively reducing the total thickness of the finished product.

[0003] However, there are many problems with the existing blind slot production. For example, the existing blind slot PCB processing methods mostly use special low-flow glue semi-cured sheets and open windows and press them together to form a cavity. Then, after the PCB is completed, the excess part of the blind slot is removed by mechanical deep milling or laser processing (called uncovering in the industry) to expose the blind slot. This processing method is feasible for products with larger sizes and low precision requirements, but when the size of the PCB is very small and the precision requirements for the blind slot are very high, there will be inherent deficiencies: the low-flow glue semi-cured sheet has poor glue flow stability, and it is easy to have problems of excessive or insufficient local glue flow; manual operation is required when uncovering, and due to the small size of the PCB, there will be thousands of blind slots on a processed board, which is extremely inefficient.

[0004] Therefore, it is necessary to provide a new circuit board manufacturing structure and a manufacturing method thereof to solve the above-mentioned existing problems. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a circuit board manufacturing structure and a manufacturing method thereof, so as to solve the problems of low blind slot manufacturing efficiency and poor blind slot precision in the prior art.

[0006] To achieve the above-mentioned object and other related objects, the present invention provides a method for manufacturing a circuit board, the manufacturing method comprising the following steps:

[0007] Providing a substrate, wherein a first surface of the substrate is defined with a blind groove area, and the blind groove area is prepared with a circuit pattern portion;

[0008] forming a protective film on the first surface that at least covers the blind groove area, wherein the protective film comprises a PI film;

[0009] The protective film is segmented by a laser cutting process to obtain a bottom protective layer located in the blind groove area;

[0010] The substrate is laminated with a prepreg assembly and a metal foil assembly, wherein the prepreg assembly comprises at least a first prepreg and a second prepreg, and the metal foil assembly comprises at least a first metal foil and a second metal foil, wherein the second metal foil, the second prepreg, the substrate, the first prepreg and the first metal foil are stacked in sequence from bottom to top, and the first prepreg covers the bottom protective layer;

[0011] Using a laser cutting process to cut along the edge of the blind groove area from one side of the first metal foil to define a uncovering area between the first metal foil and the first curing sheet;

[0012] forming a uncovering film on the surface of the uncovering area; and

[0013] The uncovering film is removed and the material layer in the uncovering area and the bottom protective layer are taken away to obtain a blind groove exposing the circuit pattern portion.

[0014] Optionally, one side of the PI film is coated with an adhesive layer, and the side of the PI film having the adhesive layer is in contact with the first side of the substrate, wherein there is a first bonding force between the PI film and the substrate, and the first bonding force is between 5g / 25mm-40g / 25mm.

[0015] Optionally, the peeling film is a blue film, and a second bonding force exists between the peeling film and the surface of the peeling area, and the peeling film is removed by hand tearing, wherein the second bonding force during the process of removing the peeling film is greater than the first bonding force.

[0016] Optionally, before removing the blue film, the method further includes a step of pretreating the blue film, wherein the pretreatment process includes: heating the uncovering film, the heating temperature of the heating treatment is between 60-120°C, and the insulation time at the heating temperature is between 10-60 minutes.

[0017] Optionally, the method of forming the bottom protective layer includes: making the entire protective film cover the surface of the substrate, dividing the protective film on the substrate, and removing the excess protective film after dividing by hand to obtain the bottom protective layer, wherein UV laser cutting is used in the process of dividing the protective film, the cutting speed of UV laser cutting is between 200-400mm / s, and the energy is between 3-6watts; or, CO2 laser cutting process is used in the process of dividing the protective film, the energy of CO2 laser cutting is between 0.5-2mj, the mask size is between 0.8-2.0mm, the pulse width is between 3-10us, and the number of shots is between 2-7.

[0018] Optionally, the thickness of the first semi-cured sheet is set based on the thickness of the PI film and the thickness of the circuit pattern part, and the thickness of the first semi-cured sheet is ≥ the thickness of the circuit pattern part * (1-the proportion of the pattern area outside the blind groove in %) + the thickness of the PI film * (1-the proportion of the blind groove area in %) + the thickness of the glass fiber cloth in the first semi-cured sheet + the compensation thickness, wherein the compensation thickness is between 4-8μm.

[0019] Optionally, the uncovering area is defined by a CO2 laser cutting process, wherein a formed cutting path covers an interface between the bottom protective layer and the first prepreg.

[0020] Optionally, during the CO2 laser cutting process for defining the uncovering area, there is a cutting spacing between adjacent cutting spots, and the cutting spacing is between 1 / 4-1 / 2 of the diameter of the cutting spot; the energy of the CO2 laser cutting is between 2-10mj, the aperture size is between 0.8-2.0mm, the pulse width is between 3-8us, and the number of shots is between 1-3.

[0021] Optionally, a bottom obstruction portion is further formed on the first surface of the substrate, and an edge of the bottom protection layer is correspondingly located on the bottom obstruction portion.

[0022] Optionally, a distance between an edge of the bottom protection layer and an edge of the bottom blocking portion away from the graphic circuit portion is between 50 μm and 500 μm.

[0023] Optionally, before forming the protective film, a process of surface treatment of the bottom hindering portion is also included, and the surface treatment process includes at least one of browning treatment and super-roughening treatment, wherein when the thickness of the bottom hindering portion is less than 15μm, the surface treatment process is selected as super-roughening treatment.

[0024] Optionally, the method for manufacturing the circuit board further includes the step of preparing an auxiliary cover-lifting portion in the blind groove area, wherein the auxiliary cover-lifting portion includes a main body portion formed on the first surface of the substrate and a groove formed in the main body portion.

[0025] Optionally, the cross-sectional shape of the groove includes at least one of a circle, a rectangle, a triangle, and a polygon, the width of the groove is between 0.15-1 mm, and when a plurality of the grooves are formed, the spacing between the grooves is between 0.2-5 mm; the distance between the edge of the groove and the edge of the cutting path of the CO2 laser cutting performed when defining the uncovering area is greater than 50 μm.

[0026] The present invention further provides a circuit board structure, which is preferably prepared by the circuit board manufacturing method of the present invention. Of course, it can also be prepared by other methods. The circuit board structure includes:

[0027] A substrate, wherein a first surface of the substrate is defined with a blind groove area, and the blind groove area is provided with a circuit pattern portion;

[0028] A bottom protective layer, covering the blind groove area, wherein the bottom protective layer comprises a PI film;

[0029] A prepreg assembly and a metal foil assembly, wherein the prepreg assembly comprises at least a first prepreg and a second prepreg, and the metal foil assembly comprises at least a first metal foil and a second metal foil, wherein the second metal foil, the second prepreg, the substrate, the first prepreg and the first metal foil are stacked in sequence from bottom to top;

[0030] The first metal foil and the first curing sheet define a uncovering area, and the uncovering area corresponds to the bottom protective layer, so that the bottom protective layer is taken away by the uncovering area material layer to form a blind groove that exposes the circuit pattern part.

[0031] Optionally, the thickness of the first semi-cured sheet is set based on the thickness of the PI film and the thickness of the circuit pattern part, wherein the thickness of the first semi-cured sheet is ≥ the thickness of the circuit pattern part * (1-the proportion of the pattern area outside the blind groove in %) + the thickness of the PI film * (1-the proportion of the blind groove area in %) + the thickness of the glass fiber cloth in the first semi-cured sheet + the compensation thickness, wherein the compensation thickness is between 4-8μm.

[0032] Optionally, a bottom obstruction portion is further formed on the first surface of the substrate, and an edge of the bottom protective layer is correspondingly located on the bottom obstruction portion, wherein a distance between the edge of the bottom protective layer and an edge of the bottom obstruction portion away from the graphic circuit portion is between 50-500 μm; and a thickness of the bottom obstruction portion is proportional to a depth of the blind groove.

[0033] Optionally, the circuit board structure further includes an auxiliary cover-lifting portion located in the blind groove area, and the cover-lifting auxiliary portion includes a main body portion formed on the first surface of the substrate and a groove formed in the main body portion.

[0034] As described above, the circuit board manufacturing structure and circuit board manufacturing method of the present invention provide a novel method for manufacturing blind grooves in PCB circuit boards. Based on the technical solution of the present invention, a PI film is used as the bottom protective layer of the circuit graphic part, and then laminated by a semi-cured sheet and a metal foil, and the blue film is peeled off. The residual glue in the blind groove production can be effectively reduced, and the method can be suitable for the production of circuit boards with smaller PCB sizes and higher requirements for blind groove production accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Shown is a process flow chart of the circuit board manufacturing method of the present invention.

[0036] Figure 2 Shown is a schematic structural diagram of a substrate provided in circuit board manufacturing according to an example of the present invention.

[0037] Figure 3 A schematic diagram showing the formation of a protective film during the manufacture of a circuit board according to an example of the present invention.

[0038] Figure 4 The diagram shows a schematic diagram of laser cutting of a protective film in circuit board manufacturing according to an example of the present invention.

[0039] Figure 5 It is a schematic diagram showing the formation of a bottom protection layer in the process of manufacturing a circuit board according to an example of the present invention.

[0040] Figure 6 The diagram shows a schematic diagram of forming a prepreg assembly and a metal foil assembly in the production of a circuit board according to an example of the present invention.

[0041] Figure 7 It is a schematic diagram showing a cover-lifting area defined by laser cutting in circuit board manufacturing according to an example of the present invention.

[0042] Figure 8 The schematic diagram of cutting without a bottom obstruction portion in the production of a circuit board according to an example of the present invention is shown.

[0043] Fig. 9 The diagram shows a schematic diagram of forming a cover film during the production of a circuit board according to an example of the present invention.

[0044] Fig.10 The diagram shows a blind groove formed after the cover is removed during the production of a circuit board according to an example of the present invention.

[0045] Fig.11 It is a diagram showing that a circuit connection structure is formed around the blind groove area during the production of the circuit board of the present invention.

[0046] FIG. 12( a ) and FIG. 12( b ) respectively show the auxiliary cover parts in different examples of the present invention.

[0047] Component number description

[0048] 100 substrates

[0049] 100a Blind slot area

[0050] 101 Circuit Graphics Department

[0051] 102 Protective film

[0052] 103 bottom protection layer

[0053] 104 First prepreg

[0054] 105 Second prepreg

[0055] 106 First Metal Foil

[0056] 107 Second Metal Foil

[0057] 108 Lid Area

[0058] 109 Peel off the cover film

[0059] 110 Bottom obstruction

[0060] 111 Blind Slot

[0061] 112 Lid opening auxiliary part

[0062] 113 Main body

[0063] 114 Grooves

[0064] Steps S1 to S7 DETAILED DESCRIPTION

[0065] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0066] For example, when describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional view showing the device structure will not be partially enlarged according to the general scale, and the schematic view is only an example, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional space dimensions of length, width and depth should be included.

[0067] For ease of description, spatial relational terms such as "under", "below", "below", "below", "above", "on", etc. may be used herein to describe the relationship between one element or feature shown in the drawings and other elements or features. It will be understood that these spatial relational terms are intended to include other directions of the device in use or operation in addition to the directions depicted in the drawings. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there can be one or more intervening layers. In addition, "between..." used in the present invention includes both endpoint values.

[0068] In the context of the present application, a structure in which a first feature is described as being "above" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0069] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and therefore the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0070] like Figure 1 As shown, the present invention provides a method for manufacturing a circuit board, and the manufacturing method comprises the following steps:

[0071] S1, providing a substrate, wherein a first surface of the substrate is defined with a blind groove area, and the blind groove area is prepared with a circuit pattern portion;

[0072] S2, forming a protective film on the first surface that at least covers the blind groove area, wherein the protective film comprises a PI film;

[0073] S3, using a laser cutting process to segment the protective film to obtain a bottom protective layer located in the blind groove area;

[0074] S4, laminating the substrate with a prepreg assembly and a metal foil assembly, wherein the prepreg assembly includes at least a first prepreg and a second prepreg, and the metal foil assembly includes at least a first metal foil and a second metal foil, wherein the second metal foil, the second prepreg, the substrate, the first prepreg and the first metal foil are stacked in sequence from bottom to top, and the first prepreg covers the bottom protective layer;

[0075] S5, cutting along the edge of the blind groove area from one side of the first metal foil using a laser cutting process to define a uncovering area between the first metal foil and the first curing sheet;

[0076] S6, forming a uncovering film on the surface of the uncovering area; and

[0077] S7, removing the uncovering film and taking away the material layer of the uncovering area and the bottom protective layer to obtain a blind groove exposing the circuit pattern portion.

[0078] The method for manufacturing a circuit board of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the above sequence does not strictly represent the preparation sequence of the method for manufacturing a circuit board protected by the present invention. Those skilled in the art may make changes between the steps according to the conventional selection in the art. Figure 1 Only one example of the preparation steps of the method for manufacturing a circuit board is shown.

[0079] First, if Figure 1 S1 and Figure 2 As shown, a substrate 100 is provided, wherein a blind groove area 100 a is defined on a first surface of the substrate 100 , and a circuit pattern portion 101 is prepared in the blind groove area 100 a .

[0080] Specifically, the substrate 100 may be a core board commonly used in the field of PCB circuit board manufacturing, or a multilayer board. The first surface may be defined according to actual conditions, such as Figure 2 As shown, it can be the upper surface of the substrate 100. In addition, the structure, distribution, thickness, etc. of the circuit pattern portion (such as copper) 101 can be set according to actual needs. In addition, the circuit pattern portion 101 is made on the surface of the substrate 100 corresponding to the blind groove area 100a, and can be prepared using existing processes. Of course, the surface area of ​​the substrate 100 outside the blind groove area 100a can also be prepared with other structures, such as connecting circuit parts, etc., which can be seen in Fig.11 As shown, an existing interlayer connection conduction structure is formed around the blind groove, which can be prepared by lamination, CO2 laser drilling, electroplating, and finally pattern etching.

[0081] Then, if Figure 1 S2 and Figure 3 As shown, a protection film 102 is formed on the first surface to at least cover the blind groove area 100a, and the protection film 102 includes a PI film.

[0082] Specifically, the protective film 102 is attached to the surface of the substrate 100, and covers the circuit pattern portion 101 set on the blind groove area 100a. Of course, it can also cover the area outside the blind groove area 100a. In one example, the protective film 102 is only a PI film. Of course, in other examples, other material layers can be set on the PI film to form the protective film 102. Among them, choosing PI film as the protective film 102 can solve the problem of easy bubbles and difficult to effectively control viscosity of other existing protective films, which makes it difficult to tear off during the removal process and leaves residual glue.

[0083] As an example, one side of the PI film is coated with an adhesive layer (not shown in the figure), and the side with the adhesive layer is in contact with the first surface of the substrate 100. The bonding force between the PI film and the substrate 100 can be regulated by the adhesive layer, wherein the bonding force of the adhesive layer is related to the composition of the adhesive and the degree of maturation of the adhesive, and the bonding force can be controlled by the degree of maturation. In one example, the PI film and the substrate 100 have a first bonding force, such as, based on the regulation of the adhesive layer, the first bonding force is between 5g / 25mm-40g / 25mm, for example, it can be 10g / 25mm, 12g / 25mm, 15g / 25mm, 20g / 25mm, 30g / 25mm. Select a PI film with a bonding force between 5g / 25mm-40g / 25mm. The adhesive side of the PI film contacts the bottom of the blind groove, which can protect the bottom of the blind groove and prevent the resin of the prepreg from flowing into the blind groove during the lamination process. At the same time, no glue on the PI film will remain on the board surface after the cover is removed; and because the bonding force is small, it is easy to remove by removing the cover.

[0084] Then, if Figure 1 S3 and Figure 4-5 As shown, the protective film 102 is divided by a laser cutting process to obtain a bottom protective layer 103 located in the blind groove area 100a.

[0085] As an example, the method of forming the bottom protective layer 103 includes: making the entire protective film 102 cover the surface of the substrate 100, dividing the protective film 102 on the substrate 100, and removing the excess protective film 102 after dividing by hand tearing. That is to say, based on the solution of the present invention, the entire PI film can be directly attached to the surface of the substrate 100, and the PI is cut on the substrate 100 to retain the PI film covering the blind groove area 100a to obtain the bottom protective layer 103. Equipment such as a film laminating machine can be omitted to improve cutting accuracy and cutting efficiency. In one example, the optical alignment point etched out of the blind groove surface is used for cutting, which can very accurately control the position accuracy of the PI film by + / -25um, while the traditional method of cutting first and then sticking to the bottom of the blind groove has a maximum accuracy of + / -75um; in addition, the present invention is highly efficient. For designs with small blind groove sizes, there may be thousands of blind grooves on a PCB board. If the method of forming first and then sticking is adopted, the efficiency is too low.

[0086] As an example, the CO2 laser cutting process is used in the process of segmenting the protective film 102, which can reduce the residual particles caused by the cutting of the PI film during the cutting process. Among them, the traditional blind groove forming process usually adopts gong forming. Compared with gong forming, CO2 laser cutting has better position accuracy. The accuracy of the cutting path and the position of the blind groove can be controlled by + / -25um, while the accuracy of gong forming is poor, generally + / -50~100um; in addition, when using CO2 laser cutting, the depth of the blind groove can be thinner, with a minimum of about 40um, while gong forming is generally at least 100um due to the problem of depth tolerance. In one example, the energy of the CO2 laser cutting is between 0.5-2mj, for example, 1mj, 1.2mj, 1.5mj, 1.8mj; the aperture size is between 0.8-2.0mm, for example, 1mm, 1.2mm, 1.5mm; the pulse width is between 3-10us, for example, 5us, 6us, 8us; the number of shots is between 2-7, for example, 3, 5, 6. In addition, in another preferred example, UV laser cutting is adopted, the cutting speed of UV laser cutting is between 200-400mm / s, for example, 250mm / s, 300mm / s, and the energy is between 3-6watts, for example, 4watts, 5watts.

[0087] Then, if Figure 1 S4 and Figure 6 As shown, the substrate 100 formed with the bottom protection layer 103 is laminated with a prepreg assembly and a metal foil (such as copper foil) assembly, wherein the prepreg assembly at least includes a first prepreg 104 and a second prepreg 105, and the metal foil assembly at least includes a first metal foil 106 and a second metal foil 107, and the second metal foil 107, the second prepreg 105, the substrate 100, the first prepreg 104 and the first metal foil 106 are stacked in sequence from bottom to top, and the first prepreg 104 covers the bottom protection layer 103. In addition, conventional steps such as drilling-electroplating-patterning-solder resist may also be included, and there may also be a multi-layer lamination process.

[0088] In one example, the second semi-cured sheet 105 and the second metal foil 107 are respectively arranged on two opposite surfaces of the substrate 100 corresponding to the first semi-cured sheet 104 and the first metal foil 106 to form a symmetrical structure. Of course, the semi-cured sheet assembly can also include other semi-cured sheets, and the metal foil assembly can also include other metal foils to form a laminated structure. Preferably, the semi-cured sheets are symmetrically distributed about the substrate, and the metal foils are symmetrically distributed about the substrate. In addition, in one example, after lamination, it is necessary to complete the processes of laser blind hole -> copper plating -> graphic etching -> solder mask according to the conventional PCB process, and then perform the laser cutting. Among them, the lamination process can be a single lamination, or it can be multiple laminations to form a PCB with a higher number of layers before cutting, which can be set according to actual needs.

[0089] As an example, the thickness of the first prepreg is set based on the thickness of the PI film and the thickness of the circuit pattern part 101, wherein the thickness of the first prepreg is greater than or equal to the thickness of the circuit pattern part * (1-the proportion of the area of ​​the pattern outside the blind groove %) + the thickness of the PI film * (1-the proportion of the area of ​​the blind groove %) + the thickness of the glass fiber cloth in the first prepreg + the compensation thickness, wherein the compensation thickness is between 4-8μm, for example, it can be 5um, 6um, 7um. Among them, the proportion of the area of ​​the pattern outside the blind groove refers to the area of ​​the first surface of the substrate outside the blind groove area, which is defined as the non-blind groove area. The non-blind groove area is also provided with other circuit patterns required in the field. This percentage is the percentage of the area of ​​this part of the circuit pattern to the area of ​​the non-blind groove area; in addition, the proportion of the area of ​​the blind groove area refers to the percentage of the area of ​​the blind groove area to the area of ​​the first surface of the entire substrate. In addition, the thickness of the glass fiber cloth in the prepreg can be known based on the existing prepreg itself. Among them, the thickness of the above-mentioned semi-cured sheet is conducive to ensuring that there is enough resin to fill the gap caused by the graphic area and the thickness of the PI film, which is conducive to preventing the formation of lamination voids; in addition, the compensation thickness is conducive to ensuring that there is still some resin residue after filling the above-mentioned gap, which is conducive to ensuring sufficient filling on the one hand, and on the other hand, it is conducive to making the product more reliable.

[0090] Then, if Figure 1 S5 and Figure 7-8 As shown, a laser cutting process is used to cut along the edge of the blind groove area 100 a from one side of the first metal foil 106 to define a uncovering area 108 in the first metal foil 106 and the first curing sheet 104 .

[0091] As an example, in the process of defining the uncovering area, the laser process is selected as a CO2 laser cutting process, wherein the formed cutting path covers the interface between the bottom protective layer 103 and the first prepreg 104. This is beneficial to the uncovering process and the removal of the bottom protective layer 103 during the uncovering process.

[0092] As an example, in the CO2 laser cutting process for defining the uncovering area, there is a cutting spacing between adjacent cutting spots, and the cutting spacing is between 1 / 4-1 / 2 of the diameter of the cutting spot; for example, it can be 1 / 3. The cutting spacing referred to here can be the distance between the two centers of the circular spot. In one example, the energy of the CO2 laser cutting is between 2-10mj, for example, it can be 5mj, 6mj, 8mj; the mask size is between 0.8-2.0mm, for example, it can be 1mm, 1.2mm, 1.5mm; the pulse width is between 3-8us, for example, it can be 5us, 6us, 7us; the number of shots is between 1-3, for example, it can be 2. So that the CO2 cutting path has a suitable width, it is also beneficial to ensure that the cutting is completed and to avoid damage to the barrier layer by the laser energy during the cutting process.

[0093] As an example, a bottom obstruction portion 110 is further formed on the first surface of the substrate 100, and the edge of the bottom protection layer 103 is correspondingly located on the bottom obstruction portion 110. The bottom obstruction portion 110 can be made of the same material based on the same process as the graphic circuit portion 101, and there is a gap between the bottom obstruction portion 110 and the graphic circuit portion.

[0094] As an example, the distance between the edge of the bottom protective layer 103 and the edge of the bottom obstruction portion 110 away from the graphic circuit portion 101, for example, the distance w in FIG. 7 , is set to be between 50-500μm, for example, it can be 100μm, 200μm, 300μm, to facilitate CO2 laser cutting and improve the deviation during laser processing. In addition, in one example, the thickness of the bottom obstruction portion 110 is positively correlated with the depth of the blind groove. To adapt to CO2 laser cutting. In one example, when the bottom obstruction portion 110 is not present, as Figure 8 As shown, UV laser cutting is preferably used to facilitate etching depth control.

[0095] As an example, before forming the protective film 102, the bottom barrier 110 is subjected to a surface treatment process, wherein the surface treatment process includes at least one of a browning treatment and an ultra-roughening treatment, wherein when the bottom barrier 110 has a thickness of less than 15 μm, for example, 8 μm, 10 μm, or 12 μm, the surface treatment process is preferably an ultra-roughening treatment, which is beneficial to preventing breakdown during the laser etching process.

[0096] Then, if Figure 1 S6 and Fig. 9 As shown, a cover film 109 is formed on the surface of the cover area 108;

[0097] Finally, if Figure 1 S3 and Figure 10-1 2, the cover film 109 is removed and the material layer of the cover area 108 and the bottom protection layer 103 are taken away, so as to obtain the blind groove 111 that exposes the circuit pattern part 101. In one example, the blind groove surface and the surface corresponding to the blind groove surface can be processed and manufactured at the same time. In addition, the blind groove can be manufactured on one side or on two opposite sides, and the design is carried out according to the actual situation. Fig.11 As shown, a schematic diagram of a single-sided blind groove is shown.

[0098] As an example, the peeling film 109 is selected to be a blue film, and there is a second bonding force between the peeling film 109 and the surface of the peeling area 108, and the peeling film 109 is removed by hand tearing, wherein the second bonding force during the process of removing the peeling film is greater than the first bonding force.

[0099] As an example, before removing the blue film, a process of pre-treating the blue film is also included, and the pre-treatment process includes: heating the uncovering film 109, for example, by heating the entire structure together. In one example, the heating temperature of the heating treatment is between 60-120°C, for example, it can be 80°C, 90°C, 100°C; the insulation time at the heating temperature is between 10-60min, for example, it can be 20min, 30min, 40min. This is conducive to controlling the size of the second bonding force, cooperating with the first bonding force, to complete the uncovering process of the present invention, so that no residual glue is left. It is conducive to the preparation of small-sized PCBs and blind grooves with high precision requirements.

[0100] In addition, in one example, the first surface of the substrate 100 may be defined with a plurality of the blind groove areas 100a, so that the process of the present invention may be used to simultaneously uncover the plurality of blind groove areas, thereby improving efficiency.

[0101] As an example, the method for manufacturing the circuit board further includes the step of preparing an auxiliary cover-lifting portion 112 in the blind groove area 100a, as shown in the auxiliary cover-lifting portion in the circuit of FIG12(a). The auxiliary cover-lifting portion 112 includes a main body 113 formed on the first surface of the substrate 100 and a groove 114 located in the main body 113. The material of the auxiliary cover-lifting portion 112 can be metal, for example, it can be prepared based on the same process and the same material as the circuit pattern portion 101 and the bottom obstruction portion 110 (when present) to obtain an initial structure, and the groove 114 is prepared therein, and the remaining part constitutes a protrusion to obtain the auxiliary cover-lifting portion 112.

[0102] In addition, in one example, the bottom obstruction part 110 can also serve as the auxiliary cover part, that is, the groove 114 is prepared in the bottom obstruction part, so that the structure also serves as the cover auxiliary part 112 including the groove and the main body, as shown in FIG. 12(b). In one example, the bottom obstruction part 110 is an annular structure, and the grooves 114 are evenly spaced in the annular bottom obstruction part. The existence of the grooves 114 can leave a gap when forming the protective film, which is conducive to the easy separation of the protective film and the bottom of the blind groove.

[0103] As an example, the cross-sectional shape of the groove 114 includes at least one of a circle, a rectangle, a triangle, and a polygon, that is, it can be one of them or a combination of two or more of the above shapes. In addition, the width of the groove 114 is between 0.15-1mm, for example, it can be 0.2mm, 0.5mm, 0.8mm, where the width here refers to the maximum size of the edge connection line, for a circle it is the diameter, for a square it is the diagonal length, and so on. In addition, when a plurality of the grooves 114 are formed, the spacing between the grooves 114 is between 0.2-5mm, for example, it can be 0.3mm, 0.4mm, where the spacing here refers to the closest place where the edges of adjacent grooves are adjacent, such as Fig.11 The distance d1 between adjacent circular grooves.

[0104] In other examples, the distance between the edge of the groove 114 and the edge of the CO2 laser cutting performed when defining the uncovering area is greater than 50 μm, for example, 60 μm, 80 μm, or 120 μm. The distance here refers to the closest distance between the edge of the groove and the laser cutting path, such as Fig.11 The distance d2 created by the circular groove.

[0105] In addition, if Figure 10-11 See Figure 1-9The present invention also provides a circuit board manufacturing structure, which is preferably prepared by the circuit board manufacturing method of the present invention. Of course, it can also be prepared by other methods. Among them, the various structural features and descriptions of the circuit board manufacturing structure described in this embodiment can refer to the description in the circuit board manufacturing method, and will not be repeated here. Among them, the circuit board manufacturing structure includes:

[0106] A substrate 100, wherein a blind groove area 100a is defined on a first surface of the substrate, and a circuit pattern portion 101 is prepared in the blind groove area;

[0107] A bottom protection layer 103, covering the blind groove area 100a, wherein the bottom protection layer 103 comprises a PI film;

[0108] A prepreg assembly and a metal foil assembly, wherein the prepreg assembly at least comprises a first prepreg 104 and a second prepreg 105, and the metal foil assembly at least comprises a first metal foil 106 and a second metal foil 107, wherein the second metal foil 107, the second prepreg 105, the substrate 100, the first prepreg 104 and the first metal foil 106 are stacked in sequence from bottom to top;

[0109] The first metal foil 106 and the first curing sheet 104 define a cover area 108 , and the cover area 108 corresponds to the bottom protective layer 103 , so that the bottom protective layer 103 is taken away by the material layer of the cover area 108 to form a blind groove 111 that exposes the circuit pattern portion 101 .

[0110] As an example, the thickness of the first semi-cured sheet 104 is set based on the thickness of the PI film and the thickness of the circuit pattern portion 101, wherein the thickness of the first semi-cured sheet 104 = the thickness of the circuit pattern portion 101 * (1-the proportion of the pattern area outside the blind groove in %) + the thickness of the PI film * (1-the proportion of the blind groove area in %) + the thickness of the glass fiber cloth in the first semi-cured sheet 104 + the compensation thickness, wherein the compensation thickness is between 4-8μm.

[0111] As an example, a bottom obstruction portion 110 is also formed on the first surface of the substrate 100, and the edge of the bottom protective layer 103 is correspondingly located on the bottom obstruction portion 110, wherein a spacing w between the edge of the bottom protective layer 103 and the edge of the bottom obstruction portion 110 away from the graphic circuit portion 101 is greater than 100 μm; and the thickness of the bottom obstruction portion 101 is proportional to the depth of the blind groove 111.

[0112] As an example, the circuit board manufacturing structure further includes an auxiliary cover portion 112 located in the blind groove area 100a, and the cover auxiliary portion includes a main body portion 113 formed on the first surface of the substrate and a groove 114 formed in the main body portion.

[0113] In summary, the circuit board manufacturing structure and circuit board manufacturing method of the present invention provide a novel method for manufacturing blind grooves in PCB circuit boards. Based on the technical solution of the present invention, the PI film is used as the bottom protective layer of the circuit pattern part, and then the semi-cured sheet and metal foil are laminated, and the blue film is uncovered, which can effectively reduce the residual glue in the blind groove manufacturing, and can be suitable for the production of circuit boards with small PCB sizes and high requirements for blind groove manufacturing precision. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0114] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for manufacturing a circuit board, characterized in that: The production method comprises the following steps: Providing a substrate, wherein a first surface of the substrate is defined with a blind groove area, and the blind groove area is prepared with a circuit pattern portion; A bottom obstruction portion is formed on the first surface, the bottom obstruction portion and the circuit pattern portion are prepared based on the same process and the same material, and a groove is prepared therein; there is a gap between the bottom obstruction portion and the circuit pattern portion, and the bottom obstruction portion also serves as an auxiliary cover-lifting portion; the width of the groove is between 0.15-1 mm, and when a plurality of the grooves are formed, the gap between the grooves is between 0.2-5 mm; A process for performing surface treatment on the bottom obstruction portion, when the thickness of the bottom obstruction portion is less than 15 μm, the surface treatment process is selected as an ultra-roughening treatment; A protective film is formed on the first surface, at least covering the blind groove area, wherein the protective film comprises a PI film; one side of the PI film is coated with an adhesive layer, and the side of the PI film having the adhesive layer is in contact with the first side of the substrate, wherein a first bonding force exists between the PI film and the substrate, and the first bonding force is between 5g / 25mm-40g / 25mm; The protective film is segmented by a laser cutting process, wherein UV laser cutting is used in the process of segmenting the protective film, wherein the cutting speed of the UV laser cutting is between 200-400 mm / s, and the energy is between 3-6 watts; or, the protective film is segmented by a CO2 laser cutting process, wherein the energy of the CO2 laser cutting is between 0.5-2 mj, the mask size is between 0.8-2.0 mm, the pulse width is between 3-10 μs, and the number of shots is between 2-7; The excess protective film after the segmentation is removed by hand tearing to obtain a bottom protective layer located in the blind groove area; the edge of the bottom protective layer is correspondingly located on the bottom obstruction part, and the distance between the edge of the bottom protective layer and the edge of the bottom obstruction part away from the circuit pattern part is between 50-500 μm; the thickness of the bottom obstruction part is positively correlated with the depth of the blind groove; The substrate is laminated with a prepreg assembly and a metal foil assembly, wherein the prepreg assembly comprises at least a first prepreg and a second prepreg, and the metal foil assembly comprises at least a first metal foil and a second metal foil, wherein the second metal foil, the second prepreg, the substrate, the first prepreg and the first metal foil are stacked in sequence from bottom to top, and the first prepreg covers the bottom protective layer; the thickness of the first prepreg is set based on the thickness of the PI film and the thickness of the circuit pattern part, and the thickness of the first prepreg is ≥ the thickness of the circuit pattern part * (1-the proportion of the pattern area outside the blind groove area in %) + the thickness of the PI film * (1-the proportion of the area of ​​the blind groove area in %) + the thickness of the glass fiber cloth in the first prepreg + the compensation thickness, wherein the compensation thickness is between 4-8 μm; A CO2 laser cutting process is used to cut along the edge of the blind groove area from one side of the first metal foil to define a uncovering area in the first metal foil and the first prepreg; in the CO2 laser cutting process for defining the uncovering area, there is a cutting spacing between adjacent cutting light spots, and the cutting spacing is between 1 / 4-1 / 2 of the diameter of the cutting light spot; the energy of the CO2 laser cutting is between 2-10mj, the aperture size is between 0.8-2.0mm, the pulse width is between 3-8μs, and the number of shots is between 1-3; and the distance between the edge of the cutting path of the CO2 laser cutting and the edge of the groove is greater than 50μm; A peeling film is formed on the surface of the peeling area; the peeling film is selected to be a blue film, and a second bonding force exists between the peeling film and the surface of the peeling area; Pre-treating the blue film, wherein the pre-treating process comprises: heating the lidding film, the heating temperature is between 60-120° C., and the insulation time at the heating temperature is between 10-60 minutes; and The peeling film is removed by hand tearing, wherein the second bonding force in the process of removing the peeling film is greater than the first bonding force; the peeling film is removed and the material layer of the peeling area and the bottom protective layer are taken away to obtain a blind groove that exposes the circuit pattern part.

2. The method for manufacturing a circuit board according to claim 1, characterized in that: The uncovering area is defined by a CO2 laser cutting process, wherein a formed cutting path covers an interface between the bottom protective layer and the first prepreg.

3. The method for manufacturing a circuit board according to claim 1, characterized in that: The process of performing surface treatment on the bottom obstruction portion further includes browning treatment.

4. The method for manufacturing a circuit board according to claim 1, characterized in that: The cross-sectional shape of the groove includes at least one of a circle, a rectangle, a triangle, and a polygon.

5. A circuit board manufacturing structure, characterized in that: The circuit board manufacturing structure includes: A substrate, wherein a first surface of the substrate is defined with a blind groove area, and the blind groove area is provided with a circuit pattern portion; A bottom obstruction portion is formed on the first surface, the bottom obstruction portion and the circuit pattern portion are prepared based on the same process and the same material, and a groove is prepared therein; there is a gap between the bottom obstruction portion and the circuit pattern portion, and the bottom obstruction portion also serves as an auxiliary cover-lifting portion; the width of the groove is between 0.15-1 mm, and when a plurality of the grooves are formed, the gap between the grooves is between 0.2-5 mm; A bottom protective layer, covering the blind groove area, the bottom protective layer comprising a PI film; one side of the PI film is coated with an adhesive layer, and the side of the PI film having the adhesive layer is in contact with the first side of the substrate, wherein the PI film and the substrate have a first bonding force, and the first bonding force is between 5g / 25mm-40g / 25mm; the edge of the bottom protective layer is correspondingly located on the bottom obstruction part, and the distance between the edge of the bottom protective layer and the edge of the bottom obstruction part away from the circuit pattern part is between 50-500μm; A prepreg assembly and a metal foil assembly, wherein the prepreg assembly comprises at least a first prepreg and a second prepreg, and the metal foil assembly comprises at least a first metal foil and a second metal foil, wherein the second metal foil, the second prepreg, the substrate, the first prepreg and the first metal foil are stacked in sequence from bottom to top; the thickness of the first prepreg is set based on the thickness of the PI film and the thickness of the circuit pattern part, and the thickness of the first prepreg is ≥ the thickness of the circuit pattern part * (1-the proportion of the pattern area outside the blind groove in %) + the thickness of the PI film * (1-the proportion of the blind groove area in %) + the thickness of the glass fiber cloth in the first prepreg + the compensation thickness, wherein the compensation thickness is between 4-8 μm; The first metal foil and the first prepreg sheet define a uncovering area, and the uncovering area corresponds to the bottom protective layer, so that the bottom protective layer is taken away based on the material layer of the uncovering area to form a blind groove that exposes the circuit pattern part.

6. The circuit board manufacturing structure according to claim 5, characterized in that: The circuit board manufacturing structure further includes an auxiliary cover portion located in the blind groove area, and the auxiliary cover portion includes a main body portion formed on the first surface of the substrate and a groove formed in the main body portion.

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