CN113163626B - Manufacturing method of ultrathin printed circuit board - Google Patents

Abstract

A manufacturing method of an ultrathin printed circuit board comprises the following steps: selecting a transparent plate as a support plate; pressing the ultrathin core plate or the copper foil on the supporting plate by adopting a light-sensitive bonding sheet; supporting the ultrathin core plate through the supporting plate, and finishing the technological processes of film pasting, exposure, development, electroplating, lamination and the like on the ultrathin core plate; after the multilayer printed circuit board is formed, the support plate and the finished ultrathin printed circuit board are detached in a laser dissociation mode. The method can effectively avoid the problems of warping, clamping and the like of the ultrathin printed circuit board in the production process, and improve the scrapping caused by the deformation of the ultrathin core board, the clamping and the like; in addition, the supporting plate used by the invention does not need to be patterned, so that the steps of film pasting, exposure, development, etching and the like are omitted, the process manufacturing flow is simplified, the yield loss caused by the related process steps is avoided, and the manufacturing cost can be greatly saved.

Description

A method of making an ultra-thin printed circuit board

technical field

The invention relates to a manufacturing technology of a printed circuit board or a semiconductor integrated circuit packaging substrate, in particular to a manufacturing method of an ultra-thin printed circuit board.

Background technique

Nowadays, electronic products are gradually miniaturized, with high wiring density, small size and light weight. As an important carrier of electronic products, printed circuit boards and packaging substrates are increasingly developing towards high-precision circuits, dense small holes and ultra-thin boards. Its total plate thickness is usually below 0.2mm.

Since the ultra-thin substrate is very thin, it is prone to large warpage, bending deformation, etc. when using the traditional method, and it is easy to produce poor quality during processing and cause scrap. For example, in the case of chemical immersion copper or electroplating copper, in the case of no frame, it is greatly affected by swing, pumping, vibration, and water impact, and it is easy to bend, stack, and have problems such as poor copper sinking and poor electroplating uniformity. In the process of graphic production, due to the deformation and warping of the board, problems such as jamming, wrinkles, and poor alignment accuracy are easy to occur, and the processing is very difficult.

In view of the above problems, the current conventional thin plate production mainly uses thin plate auxiliary frames or coreless substrates.

The thin plate auxiliary frame is generally a rectangular fixed frame composed of four borders, and the thin plate is fixed on the frame and fixed by the fixing parts. The processing process belongs to the frame processing. The use of thin plate frame processing requires modification of the equipment, and the one-time investment is high, and the size of the fixed frame is generally equivalent to that of the thin plate. For different sheet sizes, different frames need to be equipped, which is not flexible enough, and the maintenance cost of the frame is high.

The use of coreless substrate technology to make ultra-thin substrates is currently a hot spot in the research and development of high-end substrates. The production processes include: (see Figure 1)

1) adopt a support plate 1 ', this support plate 1 ' comprises epoxy resin dielectric layer 2 ' and copper foil layer 3 ';

2) at first on the copper foil layer 3' on the support plate 1', carry out filming, exposure, development, etching to make the alignment target 4';

3) Cut the central area of the adhesive sheet 5', leaving only the edge area;

4) ultra-thin substrate 6 ' comprises three parts, 7 ' is the first copper foil layer of ultra-thin substrate; 8 ' is the epoxy resin bonding sheet of ultra-thin substrate; 9 ' is the second copper foil layer of ultra-thin substrate;

5) Laminate ultra-thin substrate 6 ', bonding sheet 5 ' and support plate 1 ', and make copper circuit pattern on the second copper foil layer 9 ' of ultra-thin substrate, and make laminated structure;

6) Cut along the inner edge positions 10' and 11' of the bonding sheet 5' on the ultra-thin substrate 6' of the laminated structure, and completely cut off the bonding sheet 5', so that the ultra-thin substrate 6' and the support plate 1' separation, and finally realize the fabrication of ultra-thin substrates.

The above-mentioned existing ultra-thin substrate manufacturing process has the following disadvantages:

1. The support plate needs to be patterned to obtain the alignment target 4', which adds additional processes such as filming, exposure, development, etching, etc., which not only prolongs the process, but also increases the cost.

2. After the cutting is completed, since the size of the support plate 1' has become smaller, this support plate cannot be reused, and a new support plate must be used, which will significantly increase the cost.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for making an ultra-thin printed circuit board, which can effectively avoid problems such as warping and jamming of the ultra-thin printed circuit board in the production process, and improve the problems caused by the deformation of the ultra-thin core board, In addition, the support plate used in the present invention does not need to be patterned, and steps such as film sticking, exposure, development, etching, etc. are omitted, the process manufacturing process is simplified, and the aforementioned related process steps are avoided. Yield loss, which can greatly save manufacturing costs.

To achieve the above object, the technical scheme of the present invention is:

A method for manufacturing an ultra-thin printed circuit board, comprising the following steps:

a) Select a piece of support plate, the support plate is made of transparent or translucent material;

b) Place a light-sensitive adhesive sheet on the front of the support plate, and the area of the light-sensitive adhesive sheet is less than or equal to the area of the support plate;

c) The ultra-thin core board is placed on the photosensitive adhesive sheet, and is cured and bonded by hot pressing or vacuum lamination; the ultra-thin core board includes an insulating layer and the first and second copper foils above and below, The thickness of the ultra-thin core board is 10 to 50 μm;

d) Drilling holes on the second copper foil, chemically immersing copper or electroplating copper to achieve interlayer conduction and interconnection between the second copper foil and the first copper foil; patterning the second copper foil to form a second copper foil; Conductive circuit layer;

e) Place an adhesive sheet on the second conductive circuit layer, place a third copper foil on the adhesive sheet, and press it by hot pressing;

f) Drilling holes on the third copper foil, chemically immersing copper or electroplating copper, to achieve interlayer conduction and interconnection between the third copper foil and the second copper foil;

g) patterning the third copper foil to form a third conductive circuit layer;

h) Repeat steps e, f and g until the required number of laminated layers is completed to form a multi-layer printed circuit board;

i) laser dissociation is carried out from the back direction of the support plate to realize the separation of the photosensitive adhesive sheet and the first copper foil;

j) The first copper foil is patterned to form the first conductive circuit layer, and finally the obtained ultra-thin printed circuit board.

Further, the present invention also provides a method for making an ultra-thin printed circuit board, comprising the following steps:

a) Select a piece of support plate, and the support plate is made of transparent or translucent material;

b) Place a light-sensitive adhesive sheet on the front of the support plate, and the area of the light-sensitive adhesive sheet is less than or equal to the area of the support plate;

c) placing the first copper foil on the photosensitive adhesive sheet, and curing and bonding by means of hot pressing or vacuum lamination;

d) patterning the first copper foil to form a first conductive circuit layer;

e) placing a bonding sheet on the first conductive circuit layer, placing a second copper foil on the bonding sheet, and pressing by hot pressing, the thickness of the bonding sheet is 10-50 μm;

f) drilling the second copper foil, chemically immersing copper or electroplating copper to complete the interlayer conduction and interconnection between the first copper foil and the second copper foil;

g) patterning the second copper foil to form a second conductive circuit layer;

h) Repeat steps e, f and g until the required number of laminated layers is completed to form a multi-layer ultra-thin printed circuit board;

i) Expose from the back of the support plate to separate the photosensitive adhesive sheet from the first conductive circuit layer, and finally obtain an ultra-thin printed circuit board with a single-sided buried wire stack structure.

In addition, the present invention also provides a method for making an ultra-thin printed circuit board, comprising the following steps:

a) Select a piece of support plate, and the support plate is made of transparent or translucent material;

b) Place a light-sensitive adhesive sheet on the front of the support plate, and the area of the light-sensitive adhesive sheet is less than or equal to the area of the support plate;

c) placing the first copper foil on the photosensitive adhesive sheet, and curing and bonding by means of hot pressing or vacuum lamination;

d) patterning the first copper foil to form a first conductive circuit layer;

e) Place a first adhesive sheet on the first conductive circuit layer, place a second copper foil on top of the first adhesive sheet, and press together by hot pressing. The thickness of the first adhesive sheet is 10~ 50μm;

f) drilling the second copper foil, chemically immersing copper or electroplating copper to complete the interlayer conduction and interconnection between the first copper foil and the second copper foil;

g) patterning the second copper foil to form a second layer of conductive lines;

h) Repeat steps e, f and g until n-1 layers are completed, where n is the total number of layers of the printed circuit board;

i) A second adhesive sheet is placed on the n-1th graphic layer, and an outer layer of copper foil is placed on the second adhesive sheet, and pressed by means of hot pressing. The thickness of the second adhesive sheet is 10～50μm;

j) Use a laser to form the required circuit grooves and blind holes on the outer copper foil and the second bonding sheet;

k) Fill the circuit grooves and blind holes by means of chemical immersion copper and electroplating and hole filling;

l) removing the copper layer on the surface of the second bonding sheet by electrolytic polishing, mechanical polishing or copper thinning;

m) Expose from the back direction of the support plate to realize the separation of the photosensitive adhesive sheet and the first conductive circuit layer, and finally obtain an ultra-thin printed circuit board with a double-sided buried wire stack structure.

Furthermore, the present invention also provides a method for making an ultra-thin printed circuit board, comprising the following steps:

a) Select a piece of support plate, the support plate is made of transparent or translucent material;

b) Place a light-sensitive adhesive sheet on the front of the support plate, and the area of the light-sensitive adhesive sheet is less than or equal to the area of the support plate;

c) Place the ultra-thin core board containing the embedded capacitance material on the bonding sheet, and solidify and bond by vacuum pressing or hot pressing; the ultra-thin core board includes an insulating layer and the first and second upper and lower parts thereof Copper foil, the thickness of ultra-thin core board is 10 ~ 50μm;

d) drilling the second copper foil after curing, chemically immersing copper or electroplating copper to realize interlayer conduction and interconnection between the second copper foil and the first copper foil; patterning the second copper foil to form The second conductive circuit layer;

e) Place an adhesive sheet on the second conductive circuit layer, place a third copper foil on the adhesive sheet, and press it by hot pressing;

f) Drilling holes on the third copper foil, chemically immersing copper or electroplating copper, to achieve interlayer conduction and interconnection between the third copper foil and the second copper foil;

g) patterning the third copper foil to form a third conductive circuit layer;

h) Repeat steps e, f and g until the required number of laminated layers is completed to form a multi-layer printed circuit board;

i) Laser dissociation is carried out from the back direction of the support plate to realize the separation of the photosensitive adhesive sheet and the first copper foil;

j) The first copper foil is patterned to form a first conductive circuit layer, and finally an ultra-thin printed circuit board containing buried capacitors is obtained.

The present invention also provides a method for making an ultra-thin printed circuit board, comprising the following steps:

a) Select a piece of support plate, the support plate is made of transparent or translucent material;

b) Place a light-sensitive adhesive sheet on the front of the support plate, and the area of the light-sensitive adhesive sheet is less than or equal to the area of the support plate;

c) placing the first copper foil on the photosensitive adhesive sheet, and curing and bonding by means of hot pressing or vacuum lamination;

d) patterning the first copper foil to form a first conductive circuit layer;

e) Place a first bonding sheet on the first conductive circuit layer, and place a second copper foil above the first bonding sheet. The copper foil is a buried copper foil, which is pressed by hot pressing. Lamination parameters Like ordinary copper foil, the thickness of the first adhesive sheet is 10-50 μm;

f) Drilling holes on the second copper foil after curing, chemically immersing copper or electroplating copper to achieve interlayer conduction and interconnection between the second copper foil and the first copper foil; patterning the second copper foil to form The second conductive circuit layer;

g) placing a bonding sheet on the second conductive circuit layer, placing a third copper foil containing buried resistance material on the bonding sheet, and pressing by hot pressing;

h) Drilling the third copper foil, chemically immersing copper or electroplating copper, to achieve interlayer conduction and interconnection between the third copper foil and the second copper foil;

i) patterning the third copper foil to form a third conductive circuit layer;

j) Remove the exposed resistive material by soaking in etching solution;

k) performing further pattern transfer on the third conductive circuit layer to obtain the required resistance;

l) Repeat steps e, f and g until the required number of laminated layers is completed to form a multi-layer printed circuit board;

m) laser dissociation is carried out from the back direction of the support plate to realize the separation of the photosensitive adhesive sheet and the first copper foil;

n) The first copper foil is patterned to form a first conductive circuit layer, and finally an ultra-thin printed circuit board with buried resistance is obtained.

Preferably, the transparent or translucent materials include inorganic transparent materials and organic high molecular polymers.

Preferably, the inorganic transparent materials include glass, quartz and transparent ceramics.

Preferably, the organic high molecular polymer includes PMMA-polymethyl methacrylate, PC-polycarbonate, PS-polystyrene or PET-polyethylene terephthalate.

Preferably, the thickness of the support plate is 0.1-3 mm.

Preferably, the photosensitive adhesive sheet is a photosensitive adhesive sheet that can be decomposed by a laser light source with a wavelength of 0.01-1100 μm.

Preferably, the thickness of the ultra-thin printed circuit board is 10-200 μm.

Preferably, the material layers of the first and second adhesive sheets include epoxy resin, polyimide, polymaleimide triazine resin, polyphenylene ether or polytetrafluoroethylene and FR-4 or FR-5.

Preferably, the embedded capacitance material includes ceramics, barium titanate, epoxy resin and polyimide compounded in a certain proportion respectively.

Preferably, the first and second copper foils and the outer layer copper foil include rolled copper foil, electrolytic copper foil, reversed copper foil, carrier copper foil or buried copper foil, and the thickness of the copper foil is 1.5-64 μm .

Preferably, the resistance value of the resistor is trimmed by means of laser ablation while testing the resistance, and the resistance value is controlled within a required range.

The advantages of the present invention are:

1. The process flow is shorter and the production efficiency is higher

The traditional coreless substrate manufacturing process includes: cutting - filming - exposure - developing - etching - PP laser milling - typesetting - lamination - graphic production - cutting.

The manufacturing process of the present invention is: material cutting-typesetting-lamination-graphic production-laser separation.

The traditional coreless substrate process needs to complete the pattern production on the support plate first to obtain the alignment target. The process steps include: filming, exposure, development, etching and other four steps; moreover, the prepreg needs to be laser cut before lamination, After the production is completed, the panel needs to be split mechanically, which takes a long time and is limited by the capability of the equipment.

The method of the present invention adopts the method of laser dissociation of the photosensitive adhesive sheet, which can be separated in only a few seconds, without the above steps of filming, exposure, development, etching, etc., which greatly shortens the process flow and improves the production efficiency.

2. Lower cost

As mentioned above, the method of the present invention shortens the process flow and also reduces the production cost.

In addition, the traditional manufacturing process uses FR4 as the support plate. After the cutting is completed, the size of the support plate will be reduced by more than 0.2mm on one side, while the size of the PCB board remains unchanged, so the support plate cannot be reused. A new support board must be used, and the price of the support board usually costs about several yuan per foot. For a PCB board factory with a production capacity of hundreds of thousands of feet, the cost of the board can be saved about several million yuan per month. In addition, in the prior art, processes such as film sticking, exposure, development, and etching are required.

In the present invention, after the support plate and the thin plate are separated, the support plate can be reused, the process is shorter, and the cost of comprehensive materials, process costs, labor costs, etc. can be greatly saved every year.

3. Product yield is higher

In the method of the present invention, inorganic material is used as the support plate, which has smaller expansion and contraction, and the expansion and contraction coefficient is usually less than or equal to 3ppm/°C. While the traditional manufacturing process uses FR4 material, its expansion and contraction is usually greater than 30ppm/°C, and in the subsequent lamination process, the lamination temperature is usually greater than or equal to 190°C. For inorganic substrates, the expansion and contraction of one lamination is several hundred ppm. For traditional FR4 substrates, the expansion and contraction of one lamination is as high as several thousand ppm or even higher. The multi-layer board stack structure needs to be laminated for many times, and the dimensional stability advantage of the support board of the present invention is more obvious.

In addition, the traditional method uses mechanical cutting for separation. During the cutting process, there is mechanical stress and distortion, which is easy to cause warpage and deformation.

The present invention adopts the laser method for separation, does not generate additional stress, and greatly improves the dimensional stability of the product.

In addition, due to the uneven glue flow of traditional substrates, it may also cause poor disassembly due to adhesion during disassembly, resulting in product scrap.

However, the present invention adopts a laser dissociation method. During the laser dissociation process, the bonding force between the photosensitive adhesive sheet and the substrate is better than that of the first copper foil to be dissociated, and there is no residue on the first copper foil, which will not cause Adhesion and the corresponding secondary pollution.

4. Green and environmental protection

In the traditional coreless substrate manufacturing process, firstly, it is necessary to complete the pattern production on the support plate to obtain the alignment target. The process steps include: film sticking, exposure, development, and etching. The materials that need to be used in this process include dry film or wet film, developer solution, etchant, and a large amount of cleaning water, so a large amount of waste water will be generated.

The method of the present invention does not need the above-mentioned process steps, so the discharge of waste water can be reduced; and, after the traditional FR4 support plate is cut, the size of the support plate will be reduced, and the single side will be reduced by more than 0.2mm, while the PCB board The dimensions remain the same, so the support plate cannot be reused, and a new support plate must be used, resulting in the scrapping of a large number of materials. In the method of the present invention, after the support plate is separated from the thin plate, the support plate can be reused, saving a lot of material consumption, and being environmentally friendly and sustainable.

5. The printed circuit board is more integrated and the number of surface mounts is lower

In the assembly of printed circuit boards, various passive components, such as capacitors, resistors, inductors, etc., account for the majority, and the ratio of the number of passive components to the number of active components is (15-20):1. The number of passive components will continue to increase rapidly as the number of I/Os increases. By burying a large number of embedded passive components into the interior of the printed circuit board, the circuit length between the components can be shortened, the electrical characteristics can be improved, the effective printed circuit board packaging area can be increased, and a large number of printed circuits can be reduced. Solder joints on the board surface, thereby improving the reliability of the package and reducing the cost.

Using the method of the invention to manufacture the printed circuit board containing the buried capacitor and the buried resistance can realize the manufacture of more precise circuits.

The thickness of the buried capacitor material layer used in the fabrication of the buried capacitor process is only 8-10 microns. If the traditional process is used, direct single-sided or double-sided etching will easily cause material cracks; and, due to the ultra-thin material and poor rigidity, the production process It is easy to cause warping and deformation, and problems such as poor alignment accuracy and copper leakage occur during the etching process, resulting in scrap.

The method of the present invention uses inorganic materials such as glass as the support plate, which can solve the problem of insufficient rigidity in the above process, with smaller deformation and warpage, higher alignment accuracy, less scrap, and greatly improved product yield.

In addition, the traditional process is used to make the buried resistor, because the rigidity of the material is insufficient, and problems such as warpage and deformation will occur in the production process, and the final resistance value accuracy is controlled at ±20%.

The method of the present invention uses inorganic materials such as glass as the support plate, which can greatly reduce the scrap caused by warping and deformation; The resistance value is corrected, and the accuracy of the final resistance value can be controlled within ±2%.

Description of drawings

Figure 1 is a cross-sectional view of an existing product structure;

2 to 8 are flowcharts of Embodiment 1 of the present invention;

2 and 9 to 14 are flowcharts of Embodiment 2 of the present invention;

Figure 2, Figure 9 to Figure 12, Figure 15 to Figure 20 are flowcharts of Embodiment 3 of the present invention;

2 and 21 to 26 are flowcharts of Embodiment 4 of the present invention;

2 to 4 and FIGS. 27 to 35 are flowcharts of Embodiment 5 of the present invention.

Detailed ways

Below in conjunction with embodiment and accompanying drawing, the present invention is described in detail:

Example 1

The manufacturing method of the ultra-thin printed circuit board of the present invention comprises the following steps:

a) Select a support plate 1, the thickness of the support plate 1 is between 0.1mm-3mm, as shown in Figure 2;

b) Select light-sensitive adhesive sheet 2, ultra-thin core board (double-sided copper cladding) 3, the size of ultra-thin core board 3 is the same as that of light-sensitive adhesive sheet 2 or slightly smaller than that of light-sensitive adhesive sheet 2, and The photosensitive adhesive sheet 2 is placed on the support plate 1, and the ultra-thin core board 3 is placed on the photosensitive adhesive sheet 2, and is pressed by vacuum pressing or hot pressing, as shown in Figure 3;

c) Carry out laser drilling, chemical plating, and electroplating on the ultra-thin core board 3 to obtain blind holes 5, so that the second copper foil 301 and the first copper foil 303 are electrically connected; the pattern transfer is performed on the second copper foil to form The second conductive circuit layer 4; as shown in Figure 4; in this process, laser drilling, electroless plating, electroplating and pattern transfer all adopt the prior art;

d) placing the bonding sheet 6 on the surface of the second conductive circuit layer 4, placing the copper foil 7 above the bonding sheet 6, and pressing by hot pressing, as shown in Figure 5;

e) carry out laser drilling, electroless plating, and electroplating to obtain blind holes 8, and pattern transfer to copper foil 7 to form a third conductive circuit layer 9; repeat steps d and e to obtain circuit boards with different layers; as shown in the figure 6 shown;

f) performing exposure treatment from the back of the support plate 1, and separating the support plate 1 and the photosensitive adhesive sheet 2 from the ultra-thin circuit board, as shown in Figure 7;

g) Perform pattern transfer on the first copper foil 303 to form the first conductive circuit layer 10 to obtain an ultra-thin printed circuit board, as shown in FIG. 8 .

Example 2

The manufacturing method of the ultra-thin printed circuit board of the present invention comprises the following steps:

a) Select the support plate 1, the thickness of the support plate 1 is 0.1mm-3mm, as shown in Figure 2;

b) Place the photosensitive adhesive sheet 2 on the support plate 1, place the first copper foil 11 on the photosensitive adhesive sheet 2, and press together by vacuum pressing or hot pressing, as shown in Figure 9 ; The size of the photosensitive adhesive sheet 2 and the first copper foil 11 is slightly smaller than that of the support plate 1, and the size of the photosensitive adhesive sheet 2 and the first copper foil 11 is equivalent;

c) performing pattern transfer on the first copper foil 11 to form the first conductive circuit layer 12, as shown in FIG. 10, in this process, the pattern transfer adopts the prior art;

d) placing the adhesive sheet 13 on the surface of the first conductive circuit layer 12, placing the second copper foil 14 above the adhesive sheet 13, and pressing by hot pressing, as shown in FIG. 11 ;

e) laser drilling, electroless plating, and electroplating are performed on the second copper foil 14 to obtain blind holes 15, so that the second copper foil 14 is electrically connected to the first copper foil 11;

f) performing pattern transfer on the second copper foil 14 to form the third conductive circuit layer 16; repeating the above steps d and e in turn, circuit boards with different layers can be obtained, as shown in FIG. 12 ;

g) perform exposure treatment from the back of the support plate 1, separate the support plate 1 and the photosensitive adhesive sheet 2 from the ultra-thin circuit board, and obtain an ultra-thin printed circuit board with single-sided buried wires, as shown in Figure 13 and Figure 14 Show.

Example 3

The manufacturing method of the ultra-thin printed circuit board of the present invention, its conductive circuit comprises the following steps:

a) Select the support plate 1, the thickness of the support plate 1 is 0.1-3mm, as shown in Figure 2;

b) Select the photosensitive adhesive sheet 2 and the first copper foil 11, the size of the photosensitive adhesive sheet 2 and the first copper foil 11 is slightly smaller than that of the support plate 1; The size is the same; place the photosensitive adhesive sheet 2 on the support plate 1, place the first copper foil 11 on the photosensitive adhesive sheet 2, and press together by vacuum pressing or hot pressing, as shown in Figure 9 Show;

c) performing pattern transfer on the first copper foil 11 to form the first conductive circuit layer 12, in this process, the pattern transfer adopts the prior art, as shown in FIG. 10 ;

d) placing the adhesive sheet 13 on the surface of the first conductive circuit layer 12, placing the second copper foil 14 above the adhesive sheet 13, and pressing by hot pressing, as shown in FIG. 11 ;

e) Laser drilling, electroless plating, and electroplating are performed on the second copper foil 14 to obtain blind holes 15, so that the second copper foil 14 is electrically connected to the first copper foil 11; the pattern is transferred to the second copper foil 14, A third conductive circuit layer 16 is formed; the above steps d and e are repeated in sequence, and circuit boards with different layers can be obtained until the second outer layer, as shown in FIG. 12 ;

f) Place the second bonding sheet 17 on the surface of the secondary outer conductive circuit layer, place the outer copper foil 18 above the second bonding sheet 17, and press together by hot pressing, as shown in Figure 15;

g) laser ablation is performed on the outer layer copper foil 18 and the second bonding sheet 17 with a laser to obtain the required wire grooves 19 and blind holes 20, as shown in FIG. 16 ;

h) Fill the circuit slot 19 and the blind hole 20 by means of chemical copper and electroplating, as shown in FIG. 17 ;

i) Remove the copper layer on the dielectric surface by electrolytic polishing, mechanical polishing or copper thinning process, as shown in Figure 18;

j) Expose from the back direction of the support plate 1 to realize the separation of the support plate 1 and the first conductive circuit layer; finally, an ultra-thin printed circuit board with double-sided buried wires is obtained, as shown in FIG. 19 and FIG. 20 .

Example 4

The manufacturing method of the ultra-thin printed circuit board of the present invention comprises the following steps:

a) Select the support plate 1, the thickness of the support plate 1 is 0.1-3mm, as shown in Figure 2;

b) Select the light-sensitive adhesive sheet 2 and the ultra-thin core board 21 (double-sided copper cladding) embedded with the capacitance material. The size of the light-sensitive adhesive sheet 2 and the ultra-thin core board 21 is slightly smaller than that of the support plate 1; The size of the knot sheet 2 and the ultra-thin core board 21 are equivalent; place the photosensitive adhesive sheet 2 on the support plate 1, place the ultra-thin core board 21 on the photosensitive adhesive sheet 2, and use vacuum pressing or hot pressing. Pressing in the way; as shown in Figure 21;

c) Laser drilling, chemical plating, and electroplating are performed on the ultra-thin core board 21 to obtain blind holes 22, so that the second copper foil 2101 and the first copper foil 2103 are electrically connected; the pattern transfer is performed on the second copper foil 2101, forming a second conductive circuit layer 23, as shown in FIG. 22;

d) placing the bonding sheet on the surface of the second conductive circuit layer 23, placing the third copper foil 25 above the bonding sheet, and pressing by hot pressing, as shown in Figure 23;

e) Laser drilling, electroless plating, and electroplating are performed on the third copper foil 25 to obtain blind holes 26, so that the third copper foil is electrically connected to the second copper foil; pattern transfer is performed on the third copper foil to form a third copper foil Conductive circuit layer 27; Repeat steps d and e to obtain circuit boards with different layers, as shown in Figure 24;

f) perform exposure treatment from the back of the support plate 1, and separate the support plate 1 and the photosensitive adhesive sheet 2 from the ultra-thin circuit board, as shown in Figure 25;

g) Perform pattern transfer on the first copper foil 2103 to form a first conductive circuit layer 28 to obtain an ultra-thin printed circuit board with buried capacitors, as shown in FIG. 26 .

Example 5

The manufacturing method of the ultra-thin printed circuit board of the present invention comprises the following steps:

a) Select the support plate 1, the thickness of the support plate 1 is between 0.1mm-3mm, as shown in Figure 2;

b) Select the photosensitive adhesive sheet 2 and the ultra-thin core board (double-sided copper cladding) 3, the size of the photosensitive adhesive sheet 2 and the ultra-thin core board 3 is slightly smaller than that of the support plate 1; the photosensitive adhesive sheet 2 and The size of the ultra-thin core board 3 is equivalent; the photosensitive adhesive sheet 2 is placed on the support plate 1, and the ultra-thin core plate 3 is placed on the photosensitive adhesive sheet 2, and is pressed by vacuum pressing or hot pressing. combined, as shown in Figure 3;

c) Carry out laser drilling, chemical plating, and electroplating on the ultra-thin core board to obtain blind holes 5, so that the second copper foil is electrically connected to the first copper foil; the pattern transfer is performed on the second copper foil to form a second conductive Circuit layer 4; in this process, laser drilling, electroless plating, electroplating and pattern transfer all adopt the prior art, as shown in Figure 4;

d) The bonding sheet 29 is placed on the surface of the second conductive circuit layer 4, and the buried copper foil 30 is placed above the bonding sheet 29. The buried copper foil includes a layer of resistance material 31 and a layer of third copper foil 32 , using hot pressing for pressing, as shown in Figure 27;

e) Laser drilling, chemical plating, and electroplating are performed on the third copper foil 32 to obtain blind holes 33, so that the third copper foil is electrically connected to the second copper foil; pattern transfer is performed on the third copper foil to form a third copper foil Conductive circuit layer 34, as shown in FIG. 28;

f) Remove the exposed resistive material by soaking in etching solution, as shown in Figure 29;

g) Continue to perform pattern transfer on the third conductive circuit layer 34 to obtain the resistance 35 as shown in the figure, and further process the resistance by means of laser processing to control the resistance value within the required range, as shown in Figure 30 Show;

h) Repeat the above steps d, e, f, and g to obtain circuit boards with different layers, and the number of buried resistance layers is 1 layer to the required number of layers, as shown in Figure 31 and Figure 32;

i) perform exposure treatment from the back of the support plate 1, and separate the support plate 1 and the photosensitive adhesive sheet 2 from the ultra-thin circuit board, as shown in Figure 33 and Figure 34;

j) Perform pattern transfer on the first copper foil 303 to form a first conductive circuit layer 41 to obtain an ultra-thin printed circuit board with buried resistance, as shown in FIG. 35 .

Claims (16)

1. A manufacturing method of an ultrathin printed circuit board is characterized by comprising the following steps:

a) selecting a supporting plate, wherein the supporting plate is made of transparent or semitransparent materials;

b) placing a light sensation bonding sheet on the front surface of the supporting plate, wherein the area of the light sensation bonding sheet is smaller than or equal to that of the supporting plate;

c) placing the ultrathin core plate on a light sensation bonding sheet, and curing and bonding in a hot pressing or vacuum film pressing mode; the ultrathin core board comprises an insulating layer, a first copper foil and a second copper foil, wherein the thickness of the ultrathin core board is 10-50 mu m;

d) drilling the second copper foil, and chemically depositing copper or electroplating copper to realize interlayer conduction and interconnection between the second copper foil and the first copper foil; patterning the second copper foil to form a second conductive circuit layer;

e) placing a bonding sheet on the second conductive circuit layer, placing a third copper foil above the bonding sheet, and pressing in a hot pressing mode;

f) drilling the third copper foil, and chemically depositing copper or electroplating copper to realize interlayer conduction and interconnection between the third copper foil and the second copper foil;

g) patterning the third copper foil to form a third conductive circuit layer;

h) repeating the steps e, f and g until the required number of laminated layers is completed to form the multilayer printed circuit board;

i) laser dissociation is carried out from the back side direction of the supporting plate, and the separation of the light sensitive bonding sheet and the first copper foil is realized;

j) and carrying out pattern manufacturing on the first copper foil to form a first conductive circuit layer, and finally manufacturing the ultrathin printed circuit board.

2. A manufacturing method of an ultrathin printed circuit board is characterized by comprising the following steps:

a) selecting a supporting plate which is made of transparent or semitransparent materials;

b) placing a light sensation bonding sheet on the front surface of the supporting plate, wherein the area of the light sensation bonding sheet is smaller than or equal to that of the supporting plate;

c) placing the first copper foil on a light-sensitive adhesive sheet, and curing and bonding the first copper foil by adopting a hot-pressing or vacuum film pressing mode;

d) patterning the first copper foil to form a first conductive circuit layer;

e) placing a bonding sheet on the first conductive circuit layer, placing a second copper foil above the bonding sheet, and pressing in a hot pressing mode, wherein the thickness of the bonding sheet is 10-50 micrometers;

f) drilling the second copper foil, and chemically depositing copper or electroplating copper to complete interlayer conduction and interconnection between the first copper foil and the second copper foil;

g) patterning the second copper foil to form a second conductive circuit layer;

h) repeating the steps e, f and g until the required number of laminated layers is completed, and forming the multilayer ultrathin printed circuit board;

i) and exposing from the back direction of the supporting plate to realize the separation of the light sensitive adhesive sheet and the first conductive circuit layer, and finally preparing the ultrathin printed circuit board containing the single-sided buried wire.

3. A manufacturing method of an ultrathin printed circuit board is characterized by comprising the following steps:

a) selecting a supporting plate, wherein the supporting plate is made of transparent or semitransparent materials;

b) placing a light sensation bonding sheet on the front surface of the supporting plate, wherein the area of the light sensation bonding sheet is smaller than or equal to that of the supporting plate;

c) placing the first copper foil on a light-sensitive adhesive sheet, and curing and bonding the first copper foil by adopting a hot-pressing or vacuum film pressing mode;

d) patterning the first copper foil to form a first conductive circuit layer;

e) placing a first bonding sheet on the first conductive circuit layer, placing a second copper foil above the first bonding sheet, and pressing in a hot pressing mode, wherein the thickness of the first bonding sheet is 10-50 micrometers;

f) drilling the second copper foil, and chemically depositing copper or electroplating copper to complete interlayer conduction and interconnection between the first copper foil and the second copper foil;

g) patterning the second copper foil to form a second conductive circuit layer;

h) repeating the steps e, f and g until n-1 layers are completed, wherein n is the total number of layers of the printed circuit board;

i) placing a second bonding sheet on the n-1 th conductive circuit layer, placing an outer layer copper foil on the second bonding sheet, and pressing the second bonding sheet in a hot pressing mode, wherein the thickness of the second bonding sheet is 10-50 micrometers;

j) forming a required circuit groove and a blind hole on the outer layer copper foil and the second bonding sheet by using laser;

k) filling the circuit groove and the blind hole in a chemical copper deposition and electroplating hole filling mode;

l) removing the copper layer on the surface of the second bonding sheet by an electrolytic polishing, mechanical polishing or copper thinning process;

m) exposing from the back direction of the supporting plate to realize the separation of the light sensitive adhesive sheet and the first conductive circuit layer, and finally obtaining the ultrathin printed circuit board containing the double-sided buried wire stack structure.

4. The method of claim 3, wherein the first and second bonding sheets comprise epoxy resin, polyimide, polymaleimide triazine resin, polyphenylene oxide or polytetrafluoroethylene, and FR-4 or FR-5.

5. The method of claim 3, wherein the first, second and outer copper foils comprise rolled copper foil, electrolytic copper foil, reversed copper foil, carrier copper foil or buried copper foil, and the thickness of the copper foil is 1.5 to 64 μm.

6. A manufacturing method of an ultrathin printed circuit board is characterized by comprising the following steps:

a) selecting a supporting plate, wherein the supporting plate is made of transparent or semitransparent materials;

b) placing a light sensation bonding sheet on the front surface of the supporting plate, wherein the area of the light sensation bonding sheet is smaller than or equal to that of the supporting plate;

c) placing the ultrathin core plate containing the embedded material on a bonding sheet, and curing and bonding the ultrathin core plate containing the embedded material by adopting a vacuum pressing or hot pressing mode; the ultrathin core plate comprises an insulating layer, and a first copper foil and a second copper foil which are arranged on the upper portion and the lower portion of the insulating layer, and the thickness of the ultrathin core plate is 10-50 mu m;

d) after curing, drilling the second copper foil, and chemically depositing copper or electroplating copper to realize interlayer conduction and interconnection between the second copper foil and the first copper foil; patterning the second copper foil to form a second conductive circuit layer;

e) placing a bonding sheet on the second conductive circuit layer, placing a third copper foil above the bonding sheet, and pressing in a hot pressing mode;

f) drilling the third copper foil, and chemically depositing copper or electroplating copper to realize interlayer conduction and interconnection between the third copper foil and the second copper foil;

g) patterning the third copper foil to form a third conductive circuit layer;

h) repeating the steps e, f and g until the required number of laminated layers is completed to form the multilayer printed circuit board;

i) laser dissociation is carried out from the back side direction of the supporting plate, and the separation of the light sensitive bonding sheet and the first copper foil is realized;

j) and carrying out pattern manufacturing on the first copper foil to form a first conductive circuit layer, and finally manufacturing the ultrathin printed circuit board containing the buried capacitor.

7. The method of claim 6, wherein the capacitor-embedded material comprises a material of ceramics, barium titanate, epoxy resin and polyimide, respectively, in a certain ratio.

8. A manufacturing method of an ultrathin printed circuit board is characterized by comprising the following steps:

a) selecting a supporting plate, wherein the supporting plate is made of transparent or semitransparent materials;

b) placing a light sensation bonding sheet on the front surface of the supporting plate, wherein the area of the light sensation bonding sheet is smaller than or equal to that of the supporting plate;

c) placing the first copper foil on a light-sensitive adhesive sheet, and curing and bonding the first copper foil by adopting a hot-pressing or vacuum film pressing mode;

d) patterning the first copper foil to form a first conductive circuit layer;

e) placing a first bonding sheet on the first conductive circuit layer, placing a second copper foil above the first bonding sheet, wherein the copper foil is a buried resistance copper foil, pressing the first bonding sheet and the second bonding sheet in a hot pressing mode, the lamination parameters of the first bonding sheet are the same as those of a common copper foil, and the thickness of the first bonding sheet is 10-50 mu m;

f) after curing, drilling the second copper foil, and chemically depositing copper or electroplating copper to realize interlayer conduction and interconnection between the second copper foil and the first copper foil; patterning the second copper foil to form a second conductive circuit layer;

g) placing a bonding sheet on the second conductive circuit layer, placing a third copper foil containing a resistance embedding material above the bonding sheet, and pressing in a hot pressing mode;

h) drilling the third copper foil, and chemically depositing copper or electroplating copper to realize interlayer conduction and interconnection between the third copper foil and the second copper foil;

i) patterning the third copper foil to form a third conductive circuit layer;

j) removing the exposed resistance material by adopting an etching liquid medicine soaking mode;

k) carrying out further pattern transfer on the third conductive circuit layer to obtain the required resistance;

l) repeating the steps e, f and g until the required number of laminated layers is finished to form a multilayer printed circuit board;

m) performing laser dissociation from the back direction of the support plate to realize the separation of the light-sensitive bonding sheet and the first copper foil;

n) carrying out pattern manufacturing on the first copper foil to form a first conductive circuit layer, and finally manufacturing the ultrathin printed circuit board containing the buried resistor.

9. The method of manufacturing an ultra-thin printed circuit board as claimed in claim 8, wherein said step k corrects the resistance value of the resistor by laser ablation while testing the resistor, so as to control the resistance value within a desired range.

10. The method for manufacturing an ultra-thin printed circuit board as claimed in claim 1, 2, 3, 6 or 8, wherein the transparent or semi-transparent material comprises an inorganic transparent material and an organic high molecular polymer.

11. The method of claim 10, wherein the inorganic transparent material comprises glass, quartz, and transparent ceramic.

12. The method of claim 10, wherein the organic polymer comprises PMMA-polymethylmethacrylate, PC-polycarbonate, PS-polystyrene or PE T-polyethylene terephthalate.

13. The method for manufacturing an ultra-thin printed circuit board as claimed in claim 1, 2, 3, 6 or 8, wherein the thickness of the supporting plate is 0.1-3 mm.

14. The method for manufacturing an ultra-thin printed circuit board as claimed in claim 1, 2, 3, 6 or 8, wherein the photo-sensitive adhesive sheet is a photo-sensitive adhesive sheet that can be decomposed by a laser light source having a wavelength of 0.01 to 1100 μm.

15. The method for manufacturing an ultra-thin printed circuit board as claimed in claim 1, 2, 3, 6 or 8, wherein the thickness of the ultra-thin printed circuit board is 10 to 200 μm.

16. The method of manufacturing an ultra-thin printed circuit board as claimed in claim 1, 2, 6 or 8, wherein the first and second copper foils comprise rolled copper foil, electrolytic copper foil, reversed copper foil, carrier copper foil or buried copper foil, and the thickness of the copper foil is 1.5 to 64 μm.

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