Ultrathin multilayer circuit board structure

Abstract

The invention relates to an ultrathin multilayer circuit board structure which comprises a double-sided board. Wherein the double-sided board is composed of circuits plated on the top surface and the bottom surface of the base material board; the single-sided board is composed of a circuit plated on the face, away from the back glue face, of the single-sided insulation base material board. The bonding plate is composed of a double-face insulation base material plate, and the top face and the bottom face of the double-face insulation base material plate are both gum faces. The substrate diaphragm plate is composed of any one of a photosensitive insulating film with a gum surface, a photosensitive oil film and an insulating covering film; furthermore, any multiple of a double-sided board, a single-sided board, a bonding board and a substrate membrane board are combined to form the circuit board; the circuit board comprises more layers such as a four-layer circuit board or a six-layer circuit board; therefore, manufacturing of the thin multi-layer board is achieved, the manufacturing procedure is simple, the structure is simple, and cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-thin multi-layer circuit board structure manufacturing, and more specifically, to an ultra-thin multi-layer circuit board structure. Background Art

[0002] The existing ultra-thin multi-layer circuit board structure is usually made thinner by purchasing ultra-thin soft copper foil substrate, pure glue and surface insulation material, and adopting semi-additive process and lamination hot pressing process, but the cost is about ten times that of conventional materials; or purchasing flexible adhesive-backed copper foil and directly laminating and hot pressing. This method has a relatively simple process flow, but the cost of flexible adhesive-backed copper foil is about thirteen to fifteen times that of conventional materials, and the thickness of the circuit boards made by the above two methods is still relatively thick, which can no longer meet people's usage needs. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an ultra-thin multi-layer circuit board structure with simple processing steps, simple structure, low cost and thin thickness in view of the above-mentioned defects of the prior art.

[0004] The technical solution adopted by the present invention to solve its technical problem is:

[0005] Constructing an ultra-thin multi-layer circuit board structure, including a double-sided board; wherein the double-sided board is composed of circuits plated on the top and bottom surfaces of a substrate board;

[0006] Single-sided boards are made up of circuits plated on a single-sided insulating substrate board facing away from the adhesive backing;

[0007] The adhesive sheet is composed of a double-sided insulating substrate sheet, wherein the top and bottom surfaces of the double-sided insulating substrate sheet are both adhesive-backed surfaces;

[0008] The base film plate is composed of any one of a photosensitive insulating film with a back adhesive surface, a photosensitive oil film, and an insulating covering film;

[0009] A circuit board is made by combining any multiple of the double-sided board, the single-sided board, the adhesive board, and the substrate film board; the circuit board includes: a four-layer circuit board or a six-layer circuit board.

[0010] The ultra-thin multi-layer circuit board structure of the present invention, wherein the four-layer circuit board is composed of: the first double-layer board, the first single-layer board and the second single-layer board;

[0011] The first single-sided board is stacked on the top surface of the first double-sided board, and the adhesive backing surface of the first single-sided board is close to the first double-sided board;

[0012] The second single-sided board is stacked on the bottom surface of the first double-sided board, and the adhesive backing surface of the second single-sided board is close to the first double-sided board.

[0013] The ultra-thin multi-layer circuit board structure of the present invention, wherein the four-layer circuit board is composed of: the first double-sided board, the second double-sided board and the first adhesive board;

[0014] The first double-sided board and the second double-sided board are stacked one by one on the top surface and the bottom surface of the first adhesive board.

[0015] The ultra-thin multi-layer circuit board structure of the present invention, wherein the six-layer circuit board is composed of: the first double-layer board, the second double-layer board, the third double-layer board, the first adhesive board and the second adhesive board;

[0016] The first and second adhesive boards are stacked one by one on the top and bottom surfaces of the first double-sided board, the second double-sided board is stacked on the side of the first adhesive board facing away from the first double-sided board, and the third double-sided board is stacked on the side of the second adhesive board facing away from the first double-sided board.

[0017] The ultra-thin multi-layer circuit board structure of the present invention, wherein a through hole is provided on the four-layer circuit board or the six-layer circuit board;

[0018] The inner wall of the through hole is copper plated, and the circuit on the surface of the single-sided board away from the adhesive backing surface or the circuit on the top and bottom surfaces of the double-sided board are connected.

[0019] The ultra-thin multi-layer circuit board structure of the present invention, wherein the double-sided board, the single-sided board, the adhesive board and the substrate film board are all flexible boards or rigid boards;

[0020] The substrate plate and the substrate membrane plate are both made of insulating materials.

[0021] The ultra-thin multi-layer circuit board structure of the present invention, wherein the circuit is made by ion implanting a metal layer on the top and bottom surfaces of the substrate board or on the side of the single-sided insulating substrate board away from the back glue using a semi-additive process or an etching process;

[0022] The copper plating on the inner wall of the through hole comprises: copper plating on the inner wall of the through hole after any one of black hole, black shadow, chemical copper deposition, and ion injection of the metal layer;

[0023] The copper plating includes: electroplating copper or chemical copper plating.

[0024] The ultra-thin multi-layer circuit board structure of the present invention, wherein the first substrate film board and the second substrate film board are stacked one by one on the top surface and the bottom surface of the four-layer circuit board or the six-layer circuit board;

[0025] The adhesive backing surface of the first substrate film plate or the adhesive backing surface of the second substrate film plate is close to the circuit board.

[0026] The ultra-thin multi-layer circuit board structure of the present invention is characterized in that heat-pressing bonding is performed when any one of the double-sided board, the single-sided board, the adhesive board and the base film board is stacked.

[0027] The ultra-thin multi-layer circuit board structure of the present invention is characterized in that the circuit board is pressed or hot pressed.

[0028] The beneficial effects of the present invention are as follows: the double-sided board is composed of circuits plated on the top and bottom surfaces of the substrate board; the single-sided board is composed of circuits plated on the side of the single-sided insulating substrate board away from the adhesive backing surface; the adhesive board is composed of a double-sided insulating substrate board, wherein the top and bottom surfaces of the double-sided insulating substrate board are both adhesive backing surfaces; the substrate film board is composed of any one of a photosensitive insulating film with an adhesive backing surface, a photosensitive oil film, and an insulating covering film; further, a circuit board is made of any combination of the double-sided board, the single-sided board, the adhesive board, and the substrate film board; and the circuit board includes: a four-layer circuit board or a six-layer circuit board, or more layers; thereby realizing the production of a thinner multi-layer board, with simple processing procedures, simple structure, and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work:

[0030] Figure 1 is a cross-sectional view of an ultra-thin multi-layer circuit board structure according to a preferred embodiment 1 of the present invention;

[0031] Figure 2 is a cross-sectional view of an ultra-thin multi-layer circuit board structure according to a second preferred embodiment of the present invention;

[0032] Figure 3 It is a cross-sectional view of the ultra-thin multi-layer circuit board structure of the third preferred embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the following will be described clearly and completely in combination with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are partial embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0034] Embodiment 1:

[0035] The structure of the ultra-thin multi-layer circuit board of the preferred embodiment 1 of the present invention is as follows Figure 1 As shown, it includes a double-sided board 110; wherein the double-sided board 110 is composed of circuits 112 plated on the top and bottom surfaces of a substrate board 111;

[0036] The single-sided board 120 is composed of a circuit 112 plated on a single-sided insulating substrate board 121 facing away from the adhesive backing;

[0037] The adhesive sheet (not shown in the figure) is composed of a double-sided insulating substrate sheet, an insulating film plus glue or a mixed material of glue, etc., wherein the top and bottom surfaces of the double-sided insulating substrate sheet are both adhesive-backed surfaces, thereby avoiding short circuits in areas where the top and bottom surfaces do not need to be conductive; the use of an adhesive sheet can save a layer of insulating film stripping, achieve thinning processing, thinner thickness, easier drilling, smaller hole diameter, higher efficiency, and reduce the risk of broken holes caused by residual glue;

[0038] The base film 130 is composed of any one of a photosensitive insulating film with a back adhesive surface, a photosensitive oil film, and an insulating cover film;

[0039] A circuit board is made by combining any of the double-sided board 110, the single-sided board 120, the adhesive board, and the substrate film board 130, wherein in this embodiment, it is preferred that the adhesive board is not used to make the circuit board; the circuit board includes: a four-layer circuit board or a six-layer circuit board, and a three-layer circuit board, a five-layer circuit board, a seven-layer circuit board, an eight-layer circuit board, a nine-layer circuit board, a ten-layer circuit board and other 2+N-layer circuit boards;

[0040] The double-sided board 110 is composed of circuits 112 plated on the top and bottom surfaces of the substrate board 111; the single-sided board 120 is composed of circuits 112 plated on the single-sided insulating substrate board 121 away from the adhesive backing surface; the adhesive board is composed of a double-sided insulating substrate board, wherein the top and bottom surfaces of the double-sided insulating substrate board are both adhesive backing surfaces; the substrate film board 130 is composed of any one of a photosensitive insulating film with an adhesive backing surface, a photosensitive oil film, and an insulating covering film; further, a circuit board is made of any combination of the double-sided board 110, the single-sided board 120, the adhesive board, and the substrate film board 130; and the circuit board includes: a four-layer circuit board or a six-layer circuit board, and so on; thereby realizing the production of a thinner multi-layer board, and the processing process is simple, the structure is simple, and the cost is low.

[0041] like Figure 1 As shown, the four-layer circuit board is composed of: a first double-sided board 110, a first single-sided board 120 and a second single-sided board 120;

[0042] A first single-sided board 120 is stacked on the top surface of the first double-sided board 110 , and the adhesive backing surface of the first single-sided board 120 is close to the first double-sided board 110 ;

[0043] The second single-sided board 120 is stacked on the bottom surface of the first double-sided board 110 , and the adhesive backing surface of the second single-sided board 120 is close to the first double-sided board 110 , so as to meet different usage requirements.

[0044] like Figure 1 As shown, a through hole 140 is opened on the four-layer circuit board;

[0045] The inner wall of the through hole 140 is copper plated, and the circuit 112 on the surface of the single-sided board 120 away from the adhesive backing surface or the circuit 112 on the top and bottom surfaces of the double-sided board 110 are connected to achieve the production of the through hole 140.

[0046] like Figure 1 As shown, the double-sided board 110, the single-sided board 120 and the substrate film board 130 are all flexible boards or rigid boards to meet different usage requirements;

[0047] The substrate plate 111 and the substrate membrane plate 130 are both made of insulating materials to avoid short circuits between the circuits 112 on adjacent layers.

[0048] like Figure 1 As shown, the circuit 112 is made by ion implanting a metal layer on the top and bottom surfaces of the substrate plate 111 or the side of the single-sided insulating substrate plate 121 away from the adhesive, and then using a semi-additive process or an etching process; the circuit 112 is made by ion implanting a metal layer and then using a semi-additive process or an etching process, which simplifies the process and makes the thickness of the circuit board thinner;

[0049] The copper plating on the inner wall of the through hole 140 includes: copper plating on the inner wall of the through hole 140 after any one of black hole, black shadow, chemical copper deposition, and ion implantation of a metal layer;

[0050] Copper plating includes: electroplating copper or chemical plating copper to meet different usage requirements.

[0051] like Figure 1 As shown, a first base film 130 and a second base film 130 are stacked one by one on the top and bottom surfaces of the four-layer circuit board;

[0052] The adhesive backing surface of the first substrate film 130 or the adhesive backing surface of the second substrate film 130 is close to the circuit board, so as to insulate and protect the circuit 112 on the surface of the circuit board.

[0053] like Figure 1 As shown, when stacking any one of the single-sided board 120 and the base film board 130, heat pressing bonding is performed to make the bonding more compact and avoid cracking.

[0054] like Figure 1 As shown, the circuit board is pressed or hot pressed to perform secondary pressing or hot pressing, which further improves the quality of the circuit board.

[0055] Embodiment 2:

[0056] The structure of the ultra-thin multi-layer circuit board of the second preferred embodiment of the present invention is as follows Figure 2 As shown, it includes a double-sided board 210; wherein the double-sided board 210 is composed of circuits 212 plated on the top and bottom surfaces of a substrate board 211;

[0057] The single-sided board (not shown) is composed of a circuit 212 plated on a single-sided insulating substrate board facing away from the adhesive backing;

[0058] The adhesive sheet 220 is composed of a double-sided insulating substrate sheet, an insulating film plus glue or a mixed material of glue, etc., wherein the top and bottom surfaces of the double-sided insulating substrate sheet are both adhesive-backed surfaces, thereby avoiding short circuits in areas where the top and bottom surfaces do not need to be conductive. The adhesive sheet 220 can save a layer of insulating film stripping, thereby achieving thinning, thinning, easier drilling, smaller hole diameters, higher efficiency, and reducing the risk of broken holes caused by residual glue.

[0059] The base film plate 230 is composed of any one of a photosensitive insulating film with a back adhesive surface, a photosensitive oil film, and an insulating cover film;

[0060] A circuit board is made by combining any of the double-sided board 210, the single-sided board, the adhesive board 220, and the substrate film board 230, wherein in this embodiment, it is preferred not to use the single-sided board combination to make the circuit board; the circuit board includes: a four-layer circuit board or a six-layer circuit board, and a five-layer circuit board, a seven-layer circuit board, an eight-layer circuit board, a nine-layer circuit board, a ten-layer circuit board and other 2+N-layer circuit boards;

[0061] The double-sided board 210 is composed of circuits 212 plated on the top and bottom surfaces of the substrate board 211; the single-sided board is composed of circuits 212 plated on the single-sided insulating substrate board away from the adhesive backing surface; the adhesive board 220 is composed of a double-sided insulating substrate board, wherein the top and bottom surfaces of the double-sided insulating substrate board are both adhesive backing surfaces; the substrate film board 230 is composed of any one of a photosensitive insulating film with an adhesive backing surface, a photosensitive oil film, and an insulating covering film; further, a circuit board is made of any combination of the double-sided board 210, the single-sided board, the adhesive board 220, and the substrate film board 230; and the circuit board includes: a four-layer circuit board or a six-layer circuit board, and so on; thereby realizing the production of a thinner multi-layer board, and the processing process is simple, the structure is simple, and the cost is low.

[0062] like Figure 2 As shown, the four-layer circuit board is composed of: a first double-sided board 210, a second double-sided board 210 and a first adhesive board 220;

[0063] The first double-sided board 210 and the second double-sided board 210 are stacked one by one on the top surface and the bottom surface of the first adhesive board 220 to meet different usage requirements.

[0064] like Figure 2 As shown, a through hole 240 is opened on a four-layer circuit board;

[0065] The inner wall of the through hole 240 is copper plated, and the circuits 212 on the top and bottom surfaces of the double-sided board 210 are connected; thus, the through hole 240 is manufactured.

[0066] like Figure 2 As shown, the double-sided board 210, the adhesive board 220 and the substrate film board 230 are all flexible boards or rigid boards, meeting different usage requirements;

[0067] The substrate plate 211 and the substrate film plate 230 are both made of insulating materials to prevent short circuits of the circuits 212 on adjacent layers.

[0068] like Figure 2 As shown, the circuit 212 is made by using a semi-additive process or an etching process after ion implantation of a metal layer on the top and bottom surfaces of the substrate plate 211; the circuit 212 is made by using a semi-additive process or an etching process after ion implantation of a metal layer, the process is simplified, and the thickness of the circuit board is made thinner;

[0069] The copper plating on the inner wall of the through hole 240 includes: copper plating on the inner wall of the through hole 240 after any one of black hole, black shadow, chemical copper deposition, and ion implantation of a metal layer;

[0070] Copper plating includes: electroplating copper or chemical plating copper to meet different usage requirements.

[0071] like Figure 2 As shown, a first base film 230 and a second base film 230 are stacked one by one on the top and bottom surfaces of the four-layer circuit board;

[0072] The adhesive backing surface of the first substrate film 230 or the adhesive backing surface of the second substrate film 230 is close to the circuit board, so as to insulate and protect the circuit 212 on the surface of the circuit board.

[0073] like Figure 2 As shown, when stacking the double-sided board 210 and the base film board 230, heat-pressing bonding is performed to make the bonding tighter and avoid cracking.

[0074] like Figure 2 As shown, the circuit board is pressed or hot pressed to perform secondary pressing or hot pressing, which further improves the quality of the circuit board.

[0075] Embodiment three:

[0076] The structure of the ultra-thin multi-layer circuit board of the third preferred embodiment of the present invention is as follows Figure 3As shown, it includes a double-sided board 310; wherein the double-sided board 310 is composed of circuits 312 plated on the top and bottom surfaces of a substrate board 311;

[0077] The single-sided board (not shown) is composed of a circuit 312 plated on a single-sided insulating substrate board facing away from the adhesive backing;

[0078] The adhesive sheet 320 is composed of a double-sided insulating substrate sheet, an insulating film plus glue or a mixed material of glue, etc., wherein the top and bottom surfaces of the double-sided insulating substrate sheet are both adhesive-backed surfaces, thereby avoiding short circuits in areas where the top and bottom surfaces do not need to be conductive. The adhesive sheet 320 can save a layer of insulating film stripping, thereby achieving thinning, thinning, easier drilling, smaller hole diameters, higher efficiency, and reducing the risk of broken holes caused by residual glue.

[0079] The base film plate 330 is composed of any one of a photosensitive insulating film with a back adhesive surface, a photosensitive oil film, and an insulating cover film;

[0080] A circuit board is made by combining any of the double-sided board 310, the single-sided board, the adhesive board 320, and the substrate film board 330, wherein in this embodiment, it is preferred not to use the single-sided board combination to make the circuit board; the circuit board includes: a four-layer circuit board or a six-layer circuit board, and a five-layer circuit board, a seven-layer circuit board, an eight-layer circuit board, a nine-layer circuit board, a ten-layer circuit board, and other 3+N-layer circuit boards;

[0081] The double-sided board 310 is composed of circuits 312 plated on the top and bottom surfaces of the substrate board 311; the single-sided board is composed of circuits 312 plated on the single-sided insulating substrate board away from the adhesive backing surface; the adhesive board 320 is composed of a double-sided insulating substrate board, wherein the top and bottom surfaces of the double-sided insulating substrate board are both adhesive backing surfaces; the substrate film board 330 is composed of any one of a photosensitive insulating film with an adhesive backing surface, a photosensitive oil film, and an insulating covering film; further, a circuit board is made of any combination of the double-sided board 310, the single-sided board, the adhesive board 320, and the substrate film board 330; and the circuit board includes: a four-layer circuit board or a six-layer circuit board, and so on; thereby realizing the production of a thinner multi-layer board, and the processing process is simple, the structure is simple, and the cost is low.

[0082] like Figure 3 As shown, the six-layer circuit board is composed of: a first double-sided board 310, a second double-sided board 310, a third double-sided board 310, a first adhesive board 320 and a second adhesive board 320;

[0083] The first adhesive plate 320 and the second adhesive plate 320 are stacked one by one on the top and bottom surfaces of the first double-sided board 310, the second double-sided board 310 is stacked on the side of the first adhesive plate 320 facing away from the first double-sided board 310, and the third double-sided board 310 is stacked on the side of the second adhesive plate 320 facing away from the first double-sided board 310, so as to meet different usage requirements.

[0084] like Figure 3 As shown, a through hole 340 is opened on the six-layer circuit board;

[0085] The inner wall of the through hole 340 is copper plated, and the circuits 312 on the top and bottom surfaces of the double-sided board 310 are connected; thus, the through hole 340 is manufactured.

[0086] like Figure 3 As shown, the double-sided board 310, the adhesive board 320 and the substrate film board 330 are all flexible boards or rigid boards to meet different usage requirements;

[0087] The substrate plate 311 and the substrate film plate 330 are both made of insulating materials to prevent short circuits of the circuits 312 on adjacent layers.

[0088] like Figure 3 As shown, the circuit 312 is made by using a semi-additive process or an etching process after ion implantation of a metal layer on the top and bottom surfaces of the substrate plate 311; the circuit 312 is made by using a semi-additive process or an etching process after ion implantation of a metal layer, the process is simplified, and the thickness of the circuit board is made thinner;

[0089] The copper plating on the inner wall of the through hole 340 includes: copper plating on the inner wall of the through hole 340 after any one of black hole, black shadow, chemical copper deposition, and ion implantation of a metal layer;

[0090] Copper plating includes: electroplating copper or chemical plating copper to meet different usage requirements.

[0091] like Figure 3 As shown, a first base film 330 and a second base film 330 are stacked one by one on the top and bottom surfaces of the six-layer circuit board;

[0092] The adhesive backing surface of the first substrate film 330 or the adhesive backing surface of the second substrate film 330 is close to the circuit board, so as to insulate and protect the circuit 312 on the surface of the circuit board.

[0093] like Figure 3 As shown, when any one of the double-sided board 310, the adhesive board 320, and the base film board 330 is stacked, heat pressing bonding is performed to make the bonding more compact and avoid cracking.

[0094] like Figure 3 As shown, the circuit board is pressed or hot pressed to further improve the quality of the circuit board.

[0095] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. An ultra-thin multi-layer circuit board structure, comprising a double-sided board; characterized in that: The double-sided board is composed of circuits plated on the top and bottom surfaces of the substrate board; Single-sided boards are made up of circuits plated on a single-sided insulating substrate board facing away from the adhesive backing; The adhesive sheet is composed of a double-sided insulating substrate sheet, wherein the top and bottom surfaces of the double-sided insulating substrate sheet are both adhesive-backed surfaces; The base film plate is composed of any one of a photosensitive insulating film with a back adhesive surface, a photosensitive oil film, and an insulating covering film; A circuit board is made by combining any multiple of the double-sided board, the single-sided board, the adhesive board, and the substrate film board; the circuit board includes: a four-layer circuit board or a six-layer circuit board.

2. The ultra-thin multi-layer circuit board structure according to claim 1, characterized in that: The four-layer circuit board is composed of: the first double-layer board, the first single-layer board and the second single-layer board; The first single-sided board is stacked on the top surface of the first double-sided board, and the adhesive backing surface of the first single-sided board is close to the first double-sided board; The second single-sided board is stacked on the bottom surface of the first double-sided board, and the adhesive backing surface of the second single-sided board is close to the first double-sided board.

3. The ultra-thin multi-layer circuit board structure according to claim 1, characterized in that: The four-layer circuit board is composed of: the first double-sided board, the second double-sided board and the first adhesive board; The first double-sided board and the second double-sided board are stacked one by one on the top surface and the bottom surface of the first adhesive board.

4. The ultra-thin multi-layer circuit board structure according to claim 1, characterized in that: The six-layer circuit board is composed of: the first double-sided board, the second double-sided board, the third double-sided board, the first adhesive board and the second adhesive board; The first and second adhesive boards are stacked one by one on the top and bottom surfaces of the first double-sided board, the second double-sided board is stacked on the side of the first adhesive board facing away from the first double-sided board, and the third double-sided board is stacked on the side of the second adhesive board facing away from the first double-sided board.

5. The ultra-thin multi-layer circuit board structure according to any one of claims 2 to 4, characterized in that: Opening a through hole on the four-layer circuit board or the six-layer circuit board; The inner wall of the through hole is copper plated, and the circuit on the surface of the single-sided board away from the adhesive backing surface or the circuit on the top and bottom surfaces of the double-sided board are connected.

6. The ultra-thin multi-layer circuit board structure according to claim 1, characterized in that: The double-sided board, the single-sided board, the adhesive board and the substrate film board are all flexible boards or rigid boards; The substrate plate and the substrate membrane plate are both made of insulating materials.

7. The ultra-thin multi-layer circuit board structure according to claim 5, characterized in that: The circuit is made by using a semi-additive process or an etching process after ion implantation of a metal layer on the top and bottom surfaces of the substrate plate or on the side of the single-sided insulating substrate plate away from the back glue; The copper plating on the inner wall of the through hole comprises: copper plating on the inner wall of the through hole after any one of black hole, black shadow, chemical copper deposition, and ion injection of the metal layer; The copper plating includes: electroplating copper or chemical copper plating.

8. The ultra-thin multi-layer circuit board structure according to any one of claims 2 to 4, characterized in that: The first substrate film sheet and the second substrate film sheet are stacked one by one on the top surface and the bottom surface of the four-layer circuit board or the six-layer circuit board; The adhesive backing surface of the first substrate film plate or the adhesive backing surface of the second substrate film plate is close to the circuit board.

9. The ultra-thin multi-layer circuit board structure according to claim 8, characterized in that: When stacking any one of the double-sided board, the single-sided board, the adhesive board, and the base film board, thermal compression bonding is performed.

10. The ultra-thin multi-layer circuit board structure according to claim 1, characterized in that: The circuit board is pressed or thermally pressed.

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