Detailed description of the invention
Below in conjunction with accompanying drawing and multiple embodiment, multilayer circuit board that the technical program provides and preparation method thereof is described in further detail.
The manufacture method of the multilayer circuit board that the technical program first embodiment provides, including step:
The first step, refers to Fig. 1, it is provided that circuit substrate 10. In the present embodiment, described circuit substrate 10 is double face copper, including the first copper foil layer 11 fitted successively from top to bottom, substrate 100 and the second copper foil layer 12. Described substrate 100 is the insulating barrier being made up of insulant. In other embodiments, described substrate 100 can be multilager base plate, i.e. substrate 100 can be the structure including the alternately arranged copper foil layer of multilamellar with insulating barrier. In other embodiments, circuit substrate 10 can be single-side coated copper plate, only includes the first copper foil layer 11 and substrate 100.
Second step, sees also Fig. 2 to Fig. 4, and described first copper foil layer 11 is made the first conductive circuit layer 110, and the second copper foil layer 12 is made the second conductive circuit layer 120. It is respectively provided with a plurality of conducting wire and multiple conductive junction point in first conductive circuit layer 110 and the second conductive circuit layer 120, can by image transfer and optionally chemical etching the first copper foil layer 11 and the second copper foil layer 12 and formed, it is also possible to formed by laser selective ground ablation the first copper foil layer 11 and the second copper foil layer 12.
Described first conductive circuit layer 110 has the first pressing district 111 and the first exposed region 112. In the present embodiment, described first exposed region 112 is rectangle, and described first pressing district 111 surrounds and surround the first exposed region 112. First exposed region 112 includes a plurality of circuit 113 and multiple pad 114. After forming the first conductive circuit layer 110 and the second conductive circuit layer 120, at the first exposed region 112, the first welding resisting layer 21 is set, first welding resisting layer 21 covers a plurality of circuit 113 of the first exposed region 112, and cover the surface of substrate 100 exposed from the first exposed region 112, expose multiple pads 114 of the first exposed region 112 simultaneously. First welding resisting layer 21 can be formed by the mode printed, it is also possible to is formed by the mode fitted.
In the technical program, before making the first conductive circuit layer 110 and the second conductive circuit layer 120, also hole to form at least one first through hole in circuit substrate 10, and form conductive layer by chemical plating and electroplating technology at the hole wall of the first through hole, the first through hole to be made the first via 101. Described first via 101 can conduct the first conductive circuit layer 110 and the second conductive circuit layer 120.
3rd step, refers to Fig. 5, pressing the first alkali developable resin layer 31 and the 3rd copper foil layer 13 on the downside of circuit substrate 10, simultaneously pressing the second alkali developable resin layer 32 and the 4th copper foil layer 14 on the upside of circuit substrate 10. That is, the first alkali developable resin floor 31 is placed on the first welding resisting layer 21 surface of the first surface, pressing district 111 of the first conductive circuit layer 110 and the first exposed region 112, the 3rd copper foil layer 13 is placed on the first alkali developable resin layer 31 surface, place the second alkali developable resin layer 32 on the second conductive circuit layer 120 surface simultaneously, the 4th copper foil layer 14 is placed on the second alkali developable resin layer 32 surface, and by pressing machine disposable pressing the first alkali developable resin layer the 31, the 3rd copper foil layer 13, circuit substrate the 10, second alkali developable resin layer 32 and the 4th copper foil layer 14.
The material of described first alkali developable resin layer 31 and the second alkali developable resin layer 32 can be identical, constitutes by alkali developable resin, acid-fast alkali-proof when described alkali developable resin refers to unexposed, and the resin material that can dissolve in alkaline-based developer after exposing. For example, it is possible to be the abundant invisible ink in river, for instance, it is possible to for the photoresist of alkali-developable; Again for example, it is possible to be the alkali development resin composition in patent application 200580000757.
Can realize as follows at circuit substrate 10 both sides pressing the first alkali developable resin layer the 31, the 3rd copper foil layer the 13, second alkali developable resin layer 32 and the 4th copper foil layer 14: the dry film of alkali-developable of first fitting respectively in circuit substrate 10 both sides, then fit respectively on dry film Copper Foil, finally adopt pressing machine to carry out one step press. Certainly, can also realize as follows: first print the ink of alkali-developable then Copper Foil of fitting on the ink of upside printing in the upside of circuit substrate 10, afterwards turn over circuit substrate 10, after also passing through the operation of printing-ink, laminating Copper Foil, pressing machine is finally adopted to carry out one step press.
At circuit substrate 10 both sides pressing the first alkali developable resin layer 31, 3rd copper foil layer 13, after second alkali developable resin layer 32 and the 4th copper foil layer 14, laser drilling process can be carried out, chemical-copper-plating process and copper plating process, to form, between the 3rd copper foil layer 13 and the first conductive circuit layer 110, the first blind via hole 102 conducted, form, between the 4th copper foil layer 14 and the second conductive circuit layer 120, the second blind via hole 103 conducted, so that the 4th copper foil layer 14, second conductive circuit layer 120, first conductive circuit layer 110 and the 3rd copper foil layer 13 realize conducting, as shown in Figure 6.
4th step, see also Fig. 6 and Fig. 7,3rd copper foil layer 13 is formed the first opening 131 corresponding to the first exposed region 112, first opening 131 exposes the first alkali developable resin layer 31 corresponding to the first exposed region 112, and exposes the first alkali developable resin layer 31 exposed from the first opening 131.
3rd copper foil layer 13 forms the first opening 131 simultaneously or after, also described 3rd copper foil layer 13 is made the 3rd conductive circuit layer 130, the 4th copper foil layer 14 is made the 4th conductive circuit layer 140. Described 3rd conductive circuit layer 130 and the 4th conductive circuit layer 140 all include a plurality of conducting wire and multiple conductive junction point. So, four laminar substrate 10a can be obtained.
It is to say, the conducting wire of the 3rd conductive circuit layer 130, conductive junction point can etch formation with the first opening 131 simultaneously, it is also possible to step-etching is formed. In other words, in this step, an image transfer can be passed through and be etched selectively to the 3rd copper foil layer 13 the 3rd copper foil layer 13 to be made the 3rd conductive circuit layer 130 with the first opening 131, then expose the first alkali developable resin layer 31 exposed from the first opening 131; First time image transfer can also be passed through and be etched selectively to the material of the 3rd copper foil layer 13 removing the first opening 131 place, to form the first opening 131, then the first alkali developable resin layer 31 exposed from the first opening 131 is exposed, again through second time image transfer and be etched selectively to and remove the material of the 3rd copper foil layer 13 corresponding to the first pressing district 111, thus forming the conducting wire of the 3rd conductive circuit layer 130, conductive junction point. The conducting wire of the 4th conductive circuit layer 140, conductive junction point can concurrently form with the conducting wire of the 3rd conductive circuit layer 130, conductive junction point.
5th step, refers to Fig. 8, dissolves with alkaline-based developer and removes the first alkali developable resin layer 31 after this part is exposed, thus forming the first groove 41. Described first welding resisting layer 21 is exposed in the first groove 41. Pad 114 in first exposed region 112 of the first conductive circuit layer 110 exposed from the first welding resisting layer 21 is also exposed in the first groove 41. Described alkaline-based developer can be the NaOH solution of PH > 13 or for the KOH solution of PH > 13.
Before dissolve the first alkali developable resin layer 31 after being exposed with alkaline-based developer, or after forming the 3rd conductive circuit layer 130, or after forming the first groove 41, can at the 3rd conductive circuit layer 130 surface configuration the second welding resisting layer 22, at the 4th conductive circuit layer 140 surface configuration the 3rd welding resisting layer 23. So, four-layer circuit board 10b can be obtained.
Preferably, the second welding resisting layer the 22, the 3rd welding resisting layer 23 can be previously formed at the first alkali developable resin layer 31 being exposed with alkaline-based developer dissolving removal.
As shown in Figure 8, it includes the 4th conductive circuit layer the 140, second alkali developable resin layer 32 of pressing successively, circuit substrate the 10, first alkali developable resin layer 31 and the 3rd conductive circuit layer 130 to the four-layer circuit board 10b that above step according to first embodiment prepares. Described circuit substrate 10 includes the second conductive circuit layer 120, substrate 100 and the first conductive circuit layer 110 fitted successively. Described first to fourth conductive circuit layer 110 to 140 is conducted by first via the 101, first blind via hole 102 and the second blind via hole 103. Described four-layer circuit board 10b has the first groove 41 running through the 3rd conductive circuit layer 130 and the first alkali developable resin layer 31, is exposed in the first groove 41 so that being arranged in the first welding resisting layer 21 of the first exposed region 112 of the first conductive circuit layer 110 and the first exposed region 112 pad 114 exposed from the first welding resisting layer 21. Described first groove 41 may be used for holding electronic components and parts so that electronic devices and components are installed in the first exposed region 112 on the pad 114 exposed from the first welding resisting layer 21, so that electronic devices and components are not take up space outerpace.
The step that it will be understood by those skilled in the art that in the method making multilayer circuit board of first embodiment is not essential features. Such as, in the third step, can only pressing the first alkali developable resin layer 31 and the 3rd copper foil layer 13 on the downside of circuit substrate 10, and time different on the upside of circuit substrate 10 pressing the second alkali developable resin layer 32 and the 4th copper foil layer 14, so, after subsequent step, it is possible to make three layer circuit boards with a groove.
Except making three layer circuit boards or the four-layer circuit board with a groove, the technical program can make the multilayer circuit board of any number of plies with any amount groove. Hereinafter, there is the 8-layer printed circuit board of two grooves illustrate making.
The manufacture method of the multilayer circuit board that the technical program the second embodiment provides, including step:
The first step, refers to Fig. 7, it is provided that by the first embodiment first step to the 4th rapid four laminar substrate 10a prepared step by step.
As it was previously stated, four laminar substrate 10a include from top to bottom the 4th conductive circuit layer the 140, second alkali developable resin layer the 32, second conductive circuit layer 120 of pressing successively, substrate the 100, first conductive circuit layer the 110, first alkali developable resin layer 31 and the 3rd conductive circuit layer 130.
Second step, sees also Fig. 9 and Figure 10, and in described four laminar substrate 10a, definition the 4th conductive circuit layer 140 includes the second pressing district 141 and the second exposed region 142, and arranges the second welding resisting layer 24 on the second exposed region 142.
In the present embodiment, described second exposed region 142 is also rectangle, and described second pressing district 141 surrounds and surround the second exposed region 142. Second exposed region 142 includes a plurality of circuit 143 and multiple pad 144. Second welding resisting layer 24 covers a plurality of circuit 143 of the second exposed region 142, and covers the surface of the second alkali developable resin layer 32 exposed from the second exposed region 142, exposes multiple pads 144 of the second exposed region 142 simultaneously.
3rd step, refers to Figure 11, pressing the 3rd alkali developable resin layer 33 and the 5th copper foil layer 15 on the downside of four laminar substrate 10a, simultaneously pressing the 4th alkali developable resin layer 34 and the 6th copper foil layer 16 on the upside of circuit substrate 10. that is, the 3rd alkali developable resin layer 33 is placed on the 3rd conductive circuit layer 130 surface and the first alkali developable resin layer 31 surface exposed from the first opening 131, the 5th copper foil layer 15 is placed on the 3rd alkali developable resin layer 33 surface, place the 4th alkali developable resin floor 34 on the second surface, pressing district 141 of the 4th conductive circuit layer 140 and the second welding resisting layer 24 surface simultaneously, the 6th copper foil layer 16 is placed on the 4th alkali developable resin layer 34 surface, and adopt pressing machine disposable pressing the 6th copper foil layer 16, 4th alkali developable resin layer 34, four laminar substrate 10a, 3rd alkali developable resin layer 33 and the 5th copper foil layer 15.
Can by realizing with the 3rd akin method of step in first embodiment at four laminar substrate 10a both sides pressing the 3rd alkali developable resin layer the 33, the 5th copper foil layer the 15, the 4th alkali developable resin layers 34 and the 6th copper foil layer 16. at four laminar substrate 10a both sides pressing the 3rd alkali developable resin layers 33, 5th copper foil layer 15, after 4th alkali developable resin layer 34 and the 6th copper foil layer 16, laser drilling process can be carried out, chemical-copper-plating process and copper plating process, to form, between the 5th copper foil layer 15 and the 3rd conductive circuit layer 130, the 3rd blind via hole 104 conducted, form, between the 6th copper foil layer 16 and the 4th conductive circuit layer 140, the 4th blind via hole 105 conducted, so that the 6th copper foil layer 16, 5th copper foil layer 15, 4th conductive circuit layer 140, 3rd conductive circuit layer 130, second conductive circuit layer 120 and the first conductive circuit layer 110 realize conducting, as shown in figure 12.
4th step, refer to Figure 12,5th copper foil layer 15 is formed second opening 151 corresponding with the first opening 131,6th copper foil layer 16 is formed threeth opening 161 corresponding with the second exposed region 142, and exposes the 3rd alkali developable resin layer 33 exposed from the second opening 151 and the 4th alkali developable resin layer 34 exposed from the 3rd opening 161.
5th copper foil layer 15 forms the second opening 151 simultaneously or after, also described 5th copper foil layer 15 is made the 5th conductive circuit layer 150, the 6th copper foil layer 16 is made the 6th conductive circuit layer 160, thus forming six laminar substrate 10c. Described 5th conductive circuit layer 150 and the 6th conductive circuit layer 160 all include a plurality of conducting wire and multiple conductive junction point. It is said that in general, the conducting wire of the 5th conductive circuit layer the 150, the 6th conductive circuit layer 160, conductive junction point can concurrently form.
The conducting wire of the 5th conductive circuit layer the 150, the 6th conductive circuit layer 160, conductive junction point can etch formation with the second opening the 151, the 3rd opening 161 simultaneously, it is also possible to step-etching is formed. Illustrate for the 5th copper foil layer 15, in this step, an image transfer can be passed through and be etched selectively to the 5th copper foil layer 15 the 5th copper foil layer 15 to be made the 5th conductive circuit layer 150 with the second opening 151, then expose the 3rd alkali developable resin layer 33 exposed from the second opening 151; First time image transfer can also be passed through and be etched selectively to the material of the 5th copper foil layer 15 removing the second opening 151 place, to form the second opening 151, then the 3rd alkali developable resin layer 33 exposed from the second opening 151 is exposed, again through second time image transfer and be etched selectively to and remove corresponding to the material of the 5th copper foil layer 15 except the second opening 151, thus forming the conducting wire of the 5th conductive circuit layer 150, conductive junction point.
5th step, refers to Figure 13, pressing the 5th alkali developable resin layer 35 and the 7th copper foil layer 17 on the downside of six laminar substrate 10c, simultaneously pressing hexabasic developable resin layer 36 and the 8th copper foil layer 18 on the upside of six laminar substrate 10c. that is, the 5th alkali developable resin layer 35 is placed on the 5th conductive circuit layer 150 surface and the 3rd alkali developable resin layer 33 surface exposed from the second opening 151, the 7th copper foil layer 17 is placed on the 5th alkali developable resin layer 35 surface, place hexabasic developable resin layer 36 on the 6th conductive circuit layer 160 surface and the 4th alkali developable resin layer 34 surface exposed from the 3rd opening 161 simultaneously, the 8th copper foil layer 18 is placed on hexabasic developable resin layer 36 surface, then pressing machine disposable pressing the 8th copper foil layer 18 is adopted, hexabasic developable resin layer 36, six laminar substrate 10c, 5th alkali developable resin layer 35 and the 7th copper foil layer 17.
Can by realizing with the 3rd akin method of step in first embodiment at six laminar substrate 10c both sides pressing the 5th alkali developable resin layer the 35, the 7th copper foil layers 17, hexabasic developable resin layer 36 and the 8th copper foil layer 18. in six laminar substrate 10c both sides, pressing the 5th alkali developable resin layer 35, 7th copper foil layer 17, after hexabasic developable resin layer 36 and the 8th copper foil layer 18, laser drilling process can be carried out, chemical-copper-plating process and copper plating process, to form, between the 7th copper foil layer 17 and the 5th conductive circuit layer 150, the 5th blind via hole 106 conducted, form, between the 8th copper foil layer 18 and the 6th conductive circuit layer 160, the 6th blind via hole 107 conducted, and in six laminar substrate 10c, form the second via 108, so that the 8th copper foil layer 18, 7th copper foil layer 17, 6th conductive circuit layer 160, 5th conductive circuit layer 150, 4th conductive circuit layer 140, 3rd conductive circuit layer 130, second conductive circuit layer 120 and the first conductive circuit layer 110 realize conducting, as shown in figure 14.
6th step, refer to Figure 14,7th copper foil layer 17 is formed fourth opening 171 corresponding with the second opening 151,8th copper foil layer 18 is formed fiveth opening 181 corresponding with the 3rd opening 161, and exposes the 5th alkali developable resin layer 35 exposed from the 4th opening 171 and the hexabasic developable resin layer 36 exposed from the 5th opening 181.
7th copper foil layer 17 forms the 4th opening 171 simultaneously or after, also described 7th copper foil layer 17 is made the 7th conductive circuit layer 170,8th copper foil layer 18 forms the 5th opening 181 simultaneously or after, also described 8th copper foil layer 18 is made the 8th conductive circuit layer 180. So, namely can be made into eight laminar substrate 10d. It is said that in general, the 4th opening 171 and the 5th opening 181 can concurrently form, the 7th conductive circuit layer 170 and the 8th conductive circuit layer 180 can concurrently form. The conducting wire of the 7th conductive circuit layer the 170, the 8th conductive circuit layer 180, conductive junction point can etch formation with the 4th opening the 171, the 5th opening 181 simultaneously, it is also possible to step-etching is formed. When step-etching is formed, the step of exposure can after forming the 4th opening 171 and the 5th opening 181, carry out before forming the 7th conductive circuit layer the 170, the 8th conductive circuit layer 180, it is also possible to is carrying out after forming the 7th conductive circuit layer the 170, the 8th conductive circuit layer 180.
7th step, see also Figure 14 and Figure 15, dissolve with alkaline-based developer and remove the 5th alkali developable resin layer the 35, the 3rd alkali developable resin layer the 33, first alkali developable resin layer 31 of exposed portion, hexabasic developable resin layer 36 and the 4th alkali developable resin layer 34, thus forming the first groove 42 and the second groove 43. Can pass through to be placed in alkaline-based developer certain time by eight laminar substrate 10d leachings, or alkaline-based developer be sprayed in eight laminar substrate 10d both sides, so that alkaline-based developer dissolves the alkali developable resin layer removing exposed portion.
Specifically, the 5th alkali developable resin layer 35 being exposed exposes from the 4th opening 171, can be dissolved by alkaline-based developer and remove, after the 5th alkali developable resin layer 35 of exposed portion is dissolved removal, the 3rd alkali developable resin layer 33 exposed from the second opening 151 will also contact thus being dissolved removal with alkaline-based developer, same the first alkali developable resin layer 31 exposed from the first opening 131 also will contact thus being dissolved removal with alkaline-based developer afterwards, so, then can be formed and run through the 7th conductive circuit layer 170, 5th alkali developable resin layer 35, 5th conductive circuit layer 150, 3rd alkali developable resin layer 33, first groove 42 of the 3rd conductive circuit layer 130 and the first alkali developable resin layer 31. described first welding resisting layer 21 is exposed in the first groove 42. similar, hexabasic developable resin layer 36 after the exposure that the 5th opening 181 exposes can be dissolved by alkaline-based developer to be removed, after the hexabasic developable resin layer 36 of exposed portion is dissolved removal, the 4th alkali developable resin layer 34 exposed from the 3rd opening 161 will contact thus being dissolved removal with alkaline-based developer, so, then the second groove 43 running through the 8th conductive circuit layer 180, hexabasic developable resin layer the 36, the 6th conductive circuit layer 160 and the 4th alkali developable resin layer 34 can be formed. described second welding resisting layer 24 is exposed in the second groove 43. described alkaline-based developer can be the KOH solution of NaOH solution or the PH of PH > 13 > 13.
Before dissolving, with alkaline-based developer, the alkali developable resin layer being exposed, or after forming the 7th conductive circuit layer the 170, the 8th conductive circuit layer 180, or after forming first groove the 42, second groove 43, can at the 7th conductive circuit layer 170 surface configuration the 3rd welding resisting layer 25, at the 8th conductive circuit layer 180 surface configuration the 4th welding resisting layer 26. So, 8-layer printed circuit board 10e can be obtained. Preferably, the 3rd welding resisting layer the 25, the 4th welding resisting layer 26 can be previously formed at the alkali developable resin layer being exposed with alkaline-based developer dissolving.
As shown in figure 15, it includes the 8th conductive circuit layer 180 of pressing successively, hexabasic developable resin layer the 36, the 6th conductive circuit layer the 160, the 4th alkali developable resin layer the 34, the 4th conductive circuit layer the 140, second alkali developable resin layer 32, circuit substrate the 10, first alkali developable resin layer the 31, the 3rd conductive circuit layer the 130, the 3rd alkali developable resin layer the 33, the 5th conductive circuit layer the 150, the 5th alkali developable resin layer 35 and the 7th conductive circuit layer 170 to the 8-layer printed circuit board 10e that above step according to the second embodiment prepares. Described circuit substrate 10 includes the second conductive circuit layer 120, substrate 100 and the first conductive circuit layer 110 fitted successively. Described first to the 8th conductive circuit layer 110 to 180 realizes conducting by the first via the 101, first to the 6th the 6th blind via hole 102 to 107. Described 8-layer printed circuit board 10e has the first groove 42 running through the 7th conductive circuit layer the 170, the 5th alkali developable resin layer the 35, the 5th conductive circuit layer the 150, the 3rd alkali developable resin layer the 33, the 3rd conductive circuit layer 130 and the first alkali developable resin layer 31, so that the first welding resisting layer 21 and the pad 114 that exposes from the first welding resisting layer 21 are exposed in the first groove 42. Described 8-layer printed circuit board 10e also has the second groove 43 running through the 8th conductive circuit layer 180, hexabasic developable resin layer the 36, the 6th conductive circuit layer 160 and the 4th alkali developable resin layer 34, so that the second welding resisting layer 24 and the pad 144 that exposes from the second welding resisting layer 24 are exposed in the second groove 43. Described first groove 42 and the second groove 43 may be incorporated for holding electronic components and parts, make electronic devices and components can be installed in the first exposed region 112 on the pad 114 exposed from the first welding resisting layer 21, can also be installed in the second exposed region 142 on the pad 144 exposed from the second welding resisting layer 24, so that electronic devices and components are not take up space outerpace.
It will be understood by those skilled in the art that the deformation of the above step using the technical program can make the multilayer circuit board of other numbers of plies of the groove with other quantity. such as, the 6-layer circuit board with two grooves can be made by the step of the first step of the second embodiment to the 4th step and development. namely, if dissolve the six laminar substrate 10c removed in Figure 12 with alkaline-based developer, then can obtain the 6-layer circuit board of the groove with two different depths, one of them groove runs through the 6th conductive circuit layer 160 and the 4th alkali developable resin layer 34, and another groove runs through the 5th conductive circuit layer the 150, the 3rd alkali developable resin layer the 33, the 3rd conductive circuit layer 130 and the first alkali developable resin layer 31. again such as, in the above step of the second embodiment, if only at downside addition the first alkali developable resin layer 31 of circuit substrate 10, 3rd copper foil layer 13, 3rd alkali developable resin layer 33, 5th copper foil layer 15, 5th alkali developable resin layer 35 and the 7th copper foil layer 17, and not at upside addition the second alkali developable resin layer 32 of circuit substrate 10, 4th copper foil layer 14, 4th alkali developable resin layer 34, 6th copper foil layer 16, hexabasic developable resin layer 36 and the 8th copper foil layer 18, then by making opening, exposure, after making the step of conductive circuit layer and development, five layer circuit boards with a groove can be made, this groove runs through the 7th conductive circuit layer 170, 5th alkali developable resin layer 35, 5th conductive circuit layer 150, 3rd alkali developable resin layer 33, 3rd conductive circuit layer 130 and the first alkali developable resin layer 31. again such as, if only at downside addition the first alkali developable resin layer the 31, the 3rd copper foil layer the 13, the 3rd alkali developable resin layer the 33, the 5th copper foil layer 15 of circuit substrate 10, and other any layers of not addition, then by after the step of making opening, exposure, making conductive circuit layer and development, can making a four-layer circuit board with a groove, this groove runs through the 5th conductive circuit layer the 150, the 3rd alkali developable resin layer the 33, the 3rd conductive circuit layer 130 and the first alkali developable resin layer 31. it is, of course, also possible to made the multilayer circuit board of other numbers of plies with other structures by the deformation of the step of above example.
It will be understood by those skilled in the art that multilayer circuit board that the technical program produces is it is believed that include being pressed on circuit substrate 10 together and solderless substrate. Described circuit substrate 10 includes the first conductive circuit layer 110, and the exposed region 112 of the first conductive circuit layer 110 is provided with welding resisting layer. The number of plies of described solderless substrate is depending on the number of times of pressing, including the conductive circuit layer of the alkali developable resin layer of the multilayer grooved being pressed on together and multilamellar opening. Such as, the alkali developable resin layer of three layers fluting and the conductive circuit layer of three layers opening can be included, be positioned at solderless substrate on the downside of circuit substrate 10, that be made up of the 7th conductive circuit layer the 170, the 5th alkali developable resin layer the 35, the 5th conductive circuit layer the 150, the 3rd alkali developable resin layer the 33, the 3rd conductive circuit layer 130 and the first alkali developable resin layer 31 as shown in figure 15. The alkali developable resin layer of described multilayer grooved and the conductive circuit layer of multilamellar opening are alternately arranged, only have the conductive circuit layer of one layer of opening between every adjacent two layers alkali developable resin layer. Described solderless substrate has a groove, described groove runs through the alkali developable resin layer of every layer of fluting of solderless substrate and the conductive circuit layer of every layer of opening, the described welding resisting layer that described groove is arranged with exposed region 112 is corresponding, so that described welding resisting layer and the multiple pads 114 of exposed region 112 exposed from welding resisting layer are exposed in described groove, described groove is used for holding electronic components and parts.
In the process making multilayer circuit board of the technical program, by pressing alkali developable resin layer, the follow-up step that can pass through to develop makes formation groove easily, such then make whole processing technology all can pass through present stage comparatively ripe automatic flow and realize, eliminate the waste of human resources, and the precision making processing technology is higher, it is to avoid the error of artificial fluting and high scrappage.
It is understood that for the person of ordinary skill of the art, it is possible to conceive according to the technology of the present invention and make other various corresponding changes and deformation, and all these change and deform the protection domain that all should belong to the claims in the present invention.