A method for manufacturing a circuit board with embedded carbon oil resistor

Abstract

The application discloses a circuit board manufacturing method of embedding carbon oil resistance, comprising the following steps: taking a double-sided copper-clad plate, manufacturing a circuit pattern including a carbon oil connecting pattern, the carbon oil connecting pattern including a wire end and a connecting end, the width of the connecting end being greater than that of the wire end, pasting dry films to both sides, manufacturing a dry film window pattern in the area corresponding to the carbon oil pattern on the side where the carbon oil connecting pattern is located, performing plasma treatment, then removing the film, manufacturing a carbon oil layer in the carbon oil pattern area, taking a bonding layer prepreg, taking other layer core plates, stacking and pressing the carbon oil plate together, and performing post-process manufacturing to form the circuit board of embedding carbon oil resistance; by designing the connecting end, the carbon oil layer has a larger bonding area, the bonding force of the carbon oil layer is increased, the prepreg is stacked on the surface of the carbon oil layer, the interlayer bonding force of the carbon oil layer is improved, and the problems of falling off, multilayer board delamination and even multilayer board explosion caused by poor bonding of the carbon oil layer are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of circuit board processing, in particular to a circuit board manufacturing method for embedding carbon oil resistance. BACKGROUND

[0002] In recent years, with the rapid development of intelligent electronic products, the supporting control module technology is also constantly improving. Some application scenarios require electronic modules to be miniaturized, multifunctional and intelligent, which requires circuit boards to have high-density design. Since ordinary electronic components are generally soldered on the surface of the circuit board, they need to occupy a certain surface space, while the corresponding internal space is relatively sufficient. Therefore, the resistance is made in the form of carbon oil on the circuit board layout pattern layer, which can further enter the internal circuit board to form a high-density wiring design, improve the volume and surface space utilization rate of the circuit board, and improve the support function performance of the circuit board.

[0003] The prior art makes carbon oil patterns, generally uses silk-screen carbon oil layer and performs baking and curing to form a carbon oil resistance module, and then uses the pressing method of traditional multi-layer circuit boards to press the carbon oil layer into the internal circuit board.

[0004] However, since carbon oil generally has strong inertness, and the particle size formed is larger than that of ordinary ink, and the bonding force between the cured carbon oil layer and the insulating medium layer and the copper layer of the circuit board is low, the carbon oil layer is prone to fall off. Even if the carbon oil layer is not easy to fall off after silk-screening and baking, under the conditions of high temperature and high pressure during the pressing of the multi-layer circuit board, the bonding force of the carbon oil layer between the layers will be further poor or fall off, thereby causing the risk of delamination and explosion of the circuit board.

[0005] Therefore, based on the above background and problems, it is necessary to provide a manufacturing method that can effectively improve the bonding force of the carbon oil layer to the circuit board body and the bonding force and reliability of the carbon oil layer pressed into the internal circuit board. SUMMARY

[0006] The present application provides a circuit board manufacturing method for embedding carbon oil resistance to solve the problems of weak bonding force of the existing technology for making carbon oil layer and delamination of the carbon oil layer or poor bonding force between the layers of the multi-layer circuit board after embedding the carbon oil layer. The circuit board is processed according to design data, and the inner layer of the circuit board is designed with a carbon oil pattern. The manufacturing method comprises the following steps:

[0007] S10: Take a double-sided copper-clad plate, make a circuit pattern including a carbon oil connection pattern, and form a circuit pattern plate. The carbon oil connection pattern includes a wire end and a connection end, and the width of the connection end is greater than that of the wire end.

[0008] S20: paste dry film to both sides of the circuit pattern board, make dry film opening pattern in the area corresponding to the carbon oil pattern where the carbon oil connecting pattern is located, perform plasma treatment, and then remove the film; form an activated board;

[0009] S30: make carbon oil layer in the carbon oil pattern area of the activated board; form a carbon oil board;

[0010] S40: take the adhesive layer prepreg, take other core boards, and stack them together according to the layout structure to form a stacking structure, with the adhesive layer prepreg arranged adjacent to the carbon oil layer, and then press and combine them to form a circuit board with embedded carbon oil resistance after post-process.

[0011] Further, the length and width of the connecting end are larger than the pattern of the design data, and the connecting end is made with a grid pattern.

[0012] Further, the single side of the dry film opening pattern is larger than the carbon oil pattern.

[0013] Further, the shape of the carbon oil layer is dumbbell-shaped, the single side width of the "dumbbell" part at both ends of the dumbbell-shaped is larger than the width of the connecting end, and the width of the "central rod" part in the middle of the dumbbell-shaped is equal to the specified width in the design data.

[0014] Further, the carbon oil layer is made by silk printing.

[0015] Further, the silk printing is as follows: first silk printing 1 / 4 to 1 / 3 of the thickness of the carbon oil pattern in the design data, and baking at 125 to 160°C for 5 to 20 minutes; second silk printing the remaining thickness of the carbon oil pattern, and baking at 125 to 160°C for 30 to 70 minutes.

[0016] Further, the adhesive layer prepreg is composed of high-flow prepreg and other adhesive layers, and the high-flow prepreg is arranged adjacent to the carbon oil layer.

[0017] Further, the adhesive layer prepreg is composed of high-flow prepreg and other adhesive layers, and the high-flow prepreg is arranged adjacent to the carbon oil layer.

[0018] Further, the upper and lower surfaces of the stacking structure are respectively provided with a release layer and a heat conducting layer in sequence; the heat conducting layer is an aluminum sheet layer or a copper foil layer.

[0019] Further, the heating rate of the press is 1.0 to 2.5°C / min; after the press is completed, the cold rolling extension time is 15 to 25 minutes.

[0020] This invention designs the connectors to provide a larger bonding area for the carbon oil layer, further enhances the bonding strength between the carbon oil layer and the connectors by designing a grid pattern, and employs a secondary screen printing and secondary baking process to improve the bonding strength between the carbon oil layer and the board surface from both the screen printing and curing perspectives. It also uses a high-flow prepreg layer laminated onto the surface of the carbon oil layer to improve the interlayer bonding strength between the carbon oil layer and the prepreg. Furthermore, it incorporates a release layer and a thermally conductive layer, and uses a slow heating and extended cold pressing method to effectively improve the bonding strength between the embedded carbon oil layer and the multilayer board, resulting in a reliable carbon oil layer manufacturing effect. This addresses issues such as peeling, multilayer board delamination, and even multilayer board explosion caused by poor carbon oil layer bonding. The overall processing forms a streamlined manufacturing process with coordinated front and rear connections, enabling the standardized manufacturing of circuit boards with embedded carbon oil resistors. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 This is a flowchart illustrating the main processes included in the embodiments of the present invention;

[0023] Figure 2 A schematic diagram of a planar structure for forming a circuit pattern board including carbon oil connection patterns for this embodiment;

[0024] Figure 3 for Figure 2 A schematic diagram of the cross-sectional structure of surface AA;

[0025] Figure 4 A plan view showing the formation of an activation plate including a dry film window pattern for this embodiment;

[0026] Figure 5 for Figure 4 A schematic diagram of the cross-sectional structure of the BB surface;

[0027] Figure 6 A plan view showing the carbon oil plate including the carbon oil layer formed for this embodiment;

[0028] Figure 7 for Figure 6 A schematic diagram of the cross-sectional structure of the C-plane;

[0029] Figure 8 This is a schematic diagram of a poorly designed fabric that forms a carbon oil layer.

[0030] Figure 9 A plan view of a carbon oil layer formed by another poor design;

[0031] Figure 10 A cross-sectional view of a stack structure formed by the embodiment of the present application;

[0032] Figure 11 A cross-sectional view of a circuit board in which a carbon oil resistor is embedded.

[0033] Explanation of reference numerals:

[0034]

[0035] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present application.

[0037] It should be noted that all the directionality indications (such as up, down, left, right, front, back, inside, outside, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directionality indications also change accordingly.

[0038] In addition, the descriptions such as “first”, “second” and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first”, “second” can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of “plurality” is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0039] In addition, the technical solutions of each embodiment of the present application can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the protection scope required by the present application.

[0040] Please refer to Figure 1 ; Figure 1 The main process flowchart of the embodiment of the present application is shown.

[0041] The circuit board with embedded carbon oil resistor of the embodiment is processed according to design data, and the inner layer of the circuit board is designed with a carbon oil pattern, and the manufacturing method comprises the main manufacturing process of Figure 1 , which is described in detail in the following steps.

[0042] Please refer to Figure 2 and Figure 3 ; Figure 2 for the schematic diagram of the planar structure of the circuit pattern board including the carbon oil connection pattern formed by the embodiment; Figure 3 for the schematic diagram of the cross-sectional structure of the A-A plane of Figure 2 .

[0043] Step S10:

[0044] Take a double-sided copper-clad plate, which comprises an insulating medium layer 120, a first copper layer and a second copper layer 130, and manufacture a circuit pattern including a carbon oil connection pattern 110 to form a circuit pattern board 10; the carbon oil connection pattern 110 comprises a wire end 1110 and a connection end 1120, and the width of the connection end 1120 is greater than that of the wire end 1110.

[0045] The embodiment changes the existing technology of directly manufacturing a carbon oil layer on two wire ends to the form of first designing a connection end 1120 to a wire end 1110, so as to improve the bonding force of the carbon oil layer 310 and the wire, and prevent the carbon oil layer 310 and the wire end from easily separating.

[0046] It is worth noting that since the connection end 1120 is added, the resistance value of the carbon oil layer 310 needs to be recalculated, and the pattern of the carbon oil layer 310 needs to be redesigned, which will be described in the following process.

[0047] In the embodiment, the length and width of the connection end 1120 are larger than the pattern of the design data, and the connection end 1120 is manufactured with a grid pattern.

[0048] The embodiment designs the width and length of the connection end 1120 to be larger, which can effectively improve the bonding area of the carbon oil layer 310, thereby improving the bonding force, and further designing the grid pattern can form a structure of the subsequent silk-screened carbon oil layer 310 and the grid pattern being mutually embedded, thereby further improving the bonding force of the carbon oil and the connection end 1120.

[0049] Please refer to Figure 4 , Figure 5 ; Figure 4 for the schematic diagram of the planar structure of the activation board including the dry film windowing pattern formed by the embodiment; Figure 5 for the schematic diagram of the cross-sectional structure of the B-B plane of Figure 4 .

[0050] Step S20:

[0051] Dry film 210 is pasted to both sides of the circuit pattern board 10, and dry film opening pattern 2110 is made in the area corresponding to the carbon oil pattern where the carbon oil connecting pattern 110 is located, plasma treatment is performed, and then the film is removed; the activated board 30 is formed.

[0052] In this embodiment, the area where the carbon oil layer 310 is to be made is subjected to plasma treatment, which takes advantage of the activation of plasma treatment to improve the surface activity of the insulating medium layer 120 and the connecting end 1120 in this area, and form a uniform rough surface, providing a more easily bonded board surface basis for the subsequent production of the carbon oil layer 310, thereby improving the bonding strength.

[0053] In this embodiment, the single side of the dry film opening pattern 2110 is pre-made larger than the carbon oil pattern.

[0054] The area of the dry film opening pattern 2110 is appropriately increased, and the area subjected to plasma treatment is appropriately increased, providing a fault tolerance range for the subsequent production of the carbon oil layer 310, so that the carbon oil layer 310 can be completely attached to the area subjected to plasma treatment.

[0055] Please refer to Figure 6 , Figure 7 and Figure 8 , Figure 9 ; Figure 6 for the plan view schematic diagram of the carbon oil board formed by this embodiment including the carbon oil layer; Figure 7 for the cross-sectional structure schematic diagram of the C-C face of Figure 6 ; Figure 8 for the plan view schematic diagram of the carbon oil layer formed by this kind of bad design; Figure 9 for the plan view schematic diagram of the carbon oil layer formed by another kind of bad design.

[0056] Step S30:

[0057] The carbon oil layer 310 is made in the carbon oil pattern area of the activated board 20 to form the carbon oil board 30.

[0058] In this embodiment, the carbon oil layer 310 is made by silk screen printing method.

[0059] In this embodiment, silk screen printing is preferentially used with a mesh of 71T, 100T or 120T, the silk screen printing is as follows: the first time, silk screen printing 1 / 4 to 1 / 3 of the thickness of the carbon oil pattern in the design data, and baking at 125℃ to 160℃ for 5min to 20min; the second time, silk screen printing the remaining thickness of the carbon oil pattern, and baking at 125℃ to 160℃ for 30min to 70min.

[0060] The first silk printing forms a thinner base layer, and the pre-curing (not complete curing) using higher temperature and shorter time not only enables the carbon oil to be combined with the surface after plasma treatment in a thinner state, but also provides a similar compatible carbon oil base layer binding basis for the second silk printing, further improving the binding force of the carbon oil layer of the second silk printing, and the complete curing after the second silk printing using higher temperature and longer time improves the binding effect of the overall carbon oil layer 310.

[0061] In the embodiment, the shape of the carbon oil layer 310 is dumbbell-shaped, the single-side width of the two ends "dumbbell" parts 3110 of the dumbbell-shaped is greater than the width of the connecting end 1120, and the width of the middle "central rod" part 3120 of the dumbbell-shaped is equal to the specified width in the design data.

[0062] On the one hand, based on the design of the wire end 1110, the width of the "dumbbell" part 3110 of the carbon oil layer 310 needs to be increased at the same time, so that the carbon oil layer can effectively cover the connecting end 1120, on the other hand, since the width of the "dumbbell" part 3110 is increased, the width of the "central rod" part 3120 needs to be correspondingly reduced, so that the resistance value of the carbon oil layer 310 reaches the required resistance value, preventing the deviation of the resistance value; the specific resistance value calculation can be calculated according to the width of the "central rod" part 3120 combined with the length of the area (blank area) between the connecting ends 1120, and the specific resistance value is tested after the carbon oil layer 310 is formed.

[0063] As shown in Figure 8 、 Figure 9 If the two ends "dumbbell" parts 3110 are not pre-aligned, subsequent silk printing errors will occur, which may cause poor connection between the carbon oil layer 310 and the connecting end 1120, which may affect the resistance value effect or make the resistance value unstable.

[0064] Please refer to Figure 10 、 Figure 11 ; Figure 10 The cross-sectional structure schematic diagram of the embodiment for forming the laminated structure is shown in the figure; Figure 11 The cross-sectional structure schematic diagram of the embodiment for forming the embedded carbon oil resistor circuit board is shown in the figure.

[0065] Step S40:

[0066] Take the adhesive layer prepreg 410, and take other layer core board 420, with the carbon oil layer 30 according to the layout structure stacking structure stacking structure, the adhesive layer prepreg 410 adjacent the carbon oil layer is provided, and compression, after the process, form the embedded carbon oil resistance circuit board 50.

[0067] In the embodiment, the adhesive layer prepreg 410 is composed of high flow prepreg 4110 and other adhesive layer 4120, and the high flow prepreg 4110 is arranged adjacent to the carbon oil layer 310.

[0068] In the embodiment, the adhesive layer prepreg 410 is composed of high flow prepreg 4110 and other adhesive layer 4120, and the high flow prepreg 4110 is arranged adjacent to the carbon oil layer 310.

[0069] In the embodiment, the adhesive layer prepreg 410 is composed of high flow prepreg 4110 and other adhesive layer 4120, and the high flow prepreg 4110 is arranged adjacent to the carbon oil layer 310.

[0070] In the embodiment, the upper and lower surfaces of the stacking structure 40 are sequentially provided with release layer 430 and thermal conductive layer 440, respectively; the thermal conductive layer 440 is an aluminum sheet layer or a copper foil layer.

[0071] The setting of the thermal conductive layer 440 can effectively and efficiently conduct heat between the layers during the pressing process, especially to the high flow prepreg 4110, improve the flow effect between the layers, and improve the covering property.

[0072] In the embodiment, the heating rate of the pressing is 1.0-2.5℃ / min, preferably 1.6-18℃ / min; after the pressing is completed, the cold rolling extension time is 15-25min, preferably 20min.

[0073] The slow heating rate of the embodiment can make the adhesive prepreg and the insulating medium layer of each layer slowly and uniformly heated, so as to form a slow and sufficient filling effect of the glue, prevent the crystallization of the glue from causing poor adhesion and filling effect, prolong the cold rolling time after the pressing is completed, effectively ensure the slow self-heating of the board, prevent the shrinkage from being too large to cause delamination, and increase the bonding force between the layers.

[0074] It is worth mentioning that, due to the fact that the circuit board in the actual design and processing process is more precise, the actual structure diagram and the thickness between layers, the line width and other sizes are micron level, for example, the thickness of each layer is generally 5-50 μm, if the attached drawings of the specification are made according to the actual proportion, there is a problem of unclear illustration, therefore, in order to more clearly represent the implementation process of the manufacturing method, the drawings of the embodiment are schematic diagrams of the technical features, which do not represent the size of the actual structure diagram, nor represent the enlarged diagram of the actual structure diagram in proportion.

[0075] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made under the inventive concept of the present application, using the content of the specification and drawings, or directly / indirectly applied in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A method for manufacturing a circuit board with embedded carbon oil resistors, wherein the circuit board is fabricated according to design data, and the inner layer of the circuit board is designed with carbon oil patterns; characterized in that, The manufacturing method includes the following steps: S10: Take a double-sided copper-clad board and create a circuit pattern including carbon oil connection patterns to form a circuit pattern board; The carbon oil connection pattern includes a wire end and a connection end, wherein the width of the connection end is greater than that of the wire end; The length and width of the connecting end are pre-larged compared to the graphic in the design data, and the connecting end is made with a grid pattern; S20: Apply dry film to both sides of the circuit pattern board, create a dry film window pattern on the area corresponding to the carbon oil pattern on the side where the carbon oil connection pattern is located, perform plasma treatment, and then remove the film; to form an activated board; S30: A carbon oil layer is formed in the carbon oil pattern area of ​​the activated plate to form a carbon oil plate; The carbon oil layer is formed by screen printing. The screen printing process involves first screen printing 1 / 4 to 1 / 3 of the thickness of the carbon oil pattern in the design data, and baking it at 125°C to 160°C for 5 to 20 minutes; then screen printing the remaining thickness of the carbon oil pattern, and baking it at 125°C to 160°C for 30 to 70 minutes. S40: Take the pre-cured adhesive layer sheet and other core boards, and stack them together with the carbon oil board according to the layout structure to form a stacked structure. The pre-cured adhesive layer sheet is placed adjacent to the carbon oil layer and pressed together. After subsequent processes, the circuit board with embedded carbon oil resistor is formed.

2. The method for manufacturing a circuit board with embedded carbon oil resistors as described in claim 1, characterized in that, The single side of the dry film window pattern is pre-enlarged compared to the carbon oil pattern.

3. The method for manufacturing a circuit board with embedded carbon oil resistors as described in claim 2, characterized in that, The carbon oil layer is dumbbell-shaped, with the width of each side of the "dumbbell" portion at both ends being greater than the width of the connecting end, and the width of the middle "center rod" portion being equal to the width specified in the design data.

4. The method for manufacturing a circuit board with embedded carbon oil resistors as described in claim 1, characterized in that, The adhesive layer semi-cured sheet is composed of a high-flow adhesive semi-cured sheet and other adhesive layers stacked together, with the high-flow adhesive semi-cured sheet disposed adjacent to the carbon oil layer.

5. The method for manufacturing a circuit board with embedded carbon oil resistors as described in claim 4, characterized in that, The high-flow-rate prepreg has an adhesive content of 56% to 68%.

6. The method for manufacturing a circuit board with embedded carbon oil resistors as described in claim 1, characterized in that, The upper and lower surfaces of the stacked structure are respectively provided with a release layer and a thermally conductive layer; the thermally conductive layer is an aluminum sheet layer or a copper foil layer.

7. A method for manufacturing a circuit board with embedded carbon oil resistors as described in claim 1 or 6, characterized in that, The heating rate during the pressing process is 1.0℃ / min to 2.5℃ / min; after the pressing process is completed and the temperature is lowered, the cold pressing extension time is 15min to 25min.

Images