阅读说明：本技术 一种多层板及制作方法 (Multilayer board and manufacturing method thereof ) 是由 罗素扑 袁广 黄嘉铧 陈志敏 于 2021-09-27 设计创作，主要内容包括：本发明公开一种多层板及制作方法,其中,所述多层板包括若干两个对侧表面分别形成有线路层的陶瓷基板,所述陶瓷基板的两个线路层通过通孔形成导通连接,若干陶瓷基板定位叠加设置；所述陶瓷基板为DPC陶瓷基板,相邻陶瓷基板相对一侧的线路层的间隙分别设置有填料,所述填料的外表面与线路层外侧的金属基材表面均为平齐设置的抛光面,形成陶瓷基板的抛光叠设面；所述相邻陶瓷基板的抛光叠设面为上下相对重叠设置并冷焊粘接固定,相邻陶瓷基板相对一侧的线路层外侧的金属基材粘接在一起。多层板采用叠合层次结构的陶瓷基板,相邻陶瓷基板相对一侧的线路层的间隙分别设置有填料,避免相邻基板之间产生空隙而造成暗裂,提高产品精度及可靠性。(The invention discloses a multilayer board and a manufacturing method thereof, wherein the multilayer board comprises a plurality of ceramic substrates, wherein the two opposite side surfaces of the ceramic substrates are respectively provided with a circuit layer, the two circuit layers of the ceramic substrates are in conductive connection through holes, and the ceramic substrates are positioned and overlapped; the ceramic substrate is a DPC ceramic substrate, the gaps of the circuit layers on the opposite sides of the adjacent ceramic substrates are respectively provided with a filler, and the outer surfaces of the fillers and the surface of the metal base material on the outer side of the circuit layer are both polishing surfaces which are arranged in a flush manner to form polishing stacking surfaces of the ceramic substrates; the polishing stacking surfaces of the adjacent ceramic substrates are oppositely overlapped up and down and are fixedly bonded by cold welding, and the metal base materials on the outer side of the circuit layer on one opposite side of the adjacent ceramic substrates are bonded together. The multilayer board adopts the ceramic substrate of coincide hierarchy, and the clearance on the circuit layer of adjacent ceramic substrate relative one side is provided with the filler respectively, avoids producing the space between the adjacent substrate and causes the dark split, improves product precision and reliability.)

1. A multilayer board comprises a plurality of ceramic substrates, wherein circuit layers are respectively formed on the surfaces of the two opposite sides of each ceramic substrate, the two circuit layers of the ceramic substrates are in conduction connection through holes, and the ceramic substrates are positioned and stacked; the method is characterized in that:

the ceramic substrate is a DPC ceramic substrate, the gaps of the circuit layers on the opposite sides of the adjacent ceramic substrates are respectively provided with a filler, and the outer surfaces of the fillers and the surface of the metal base material on the outer side of the circuit layer are both polishing surfaces which are arranged in a flush manner to form polishing stacking surfaces of the ceramic substrates; the polishing stacking surfaces of the adjacent ceramic substrates are oppositely overlapped up and down and are fixedly bonded by cold welding, and the metal base materials on the outer side of the circuit layer on one opposite side of the adjacent ceramic substrates are bonded together.

2. A multilayer plate according to claim 1, wherein: the polishing surface has a surface roughness of less than 0.05 microns.

3. A multilayer plate according to claim 1, wherein: the filler is insulating filler.

4. A multilayer plate according to claim 1, wherein: the filler fills the gap between the circuit layers on the opposite sides of the adjacent ceramic substrates.

5. A multilayer plate according to claim 1, wherein: the metal substrate is copper, silver, aluminum, gold, tungsten, nickel or iron.

6. A multilayer plate according to claim 1, wherein: the filler is a mixture of insulating powder and a curing agent.

7. The manufacturing method of the multilayer board is characterized by comprising the following steps: -making a multilayer sheet according to any one of claims 1 to 6, said making method comprising the steps of:

step 1: manufacturing more than two polished circuit boards, wherein the manufacturing steps of each polished circuit board comprise: step 1-1: manufacturing a ceramic substrate by adopting a DPC technology; step 1-2: filling the filler into a gap formed between circuit layers of the ceramic substrate, and after the filler is solidified, carrying out surface treatment on the surface of the ceramic substrate to form a polished circuit board;

step 2: the polishing overlapping surfaces of more than two polishing circuit boards are oppositely overlapped through CCD positioning, and the polishing circuit boards which are overlapped are exhausted;

and step 3: and bonding the adjacent polishing overlapping surfaces of the overlapped polishing circuit boards together by a cold welding method, so that the metal base materials on the outer sides of the circuit layers on the opposite sides of the adjacent ceramic substrates are bonded together.

8. The method of making a multilayer sheet according to claim 7, wherein: in the step 1-2, the insulating powder and the curing agent are mixed to be used as the filler, the filler is stirred into slurry, and the slurry filler is coated on the surface of the ceramic substrate.

9. The method of making a multilayer sheet according to claim 7, wherein: in the step 1-2, the surface of the ceramic substrate is ground to expose the metal base material of the circuit layer, and then the outer surface of the ceramic substrate is polished to form the polished circuit board.

10. The method of making a multilayer sheet according to claim 7, wherein: in the step 1-2, the gap formed between the circuit layers of the ceramic substrate is filled with the filler.

Technical Field

The invention relates to the technical field of multilayer boards, in particular to a multilayer board and a manufacturing method thereof.

Background

Good device heat dissipation relies on optimized heat dissipation structure design, packaging material selection, packaging manufacturing processes, and the like. Ceramic substrates are increasingly used in electronic packaging, particularly in power electronic devices such as insulated gate bipolar transistors, laser diodes, light emitting diodes, and focused photovoltaic packaging, due to their good thermal conductivity, heat resistance, insulation properties, low thermal expansion coefficient, and continuous reduction in cost.

At present, a ceramic multilayer substrate is prepared into raw ceramic plates by a tape casting method, then holes are punched on the raw ceramic plates, metal slurry is arranged after the holes are filled, the raw ceramic plates with the wires are positioned and superposed one by one, and then hot pressing sintering is carried out. In the prior art, the temperature of the ceramic multilayer substrate during hot-pressing sintering is generally set to 800-1200 ℃, and in addition, in the prior art, the ceramic multilayer substrate manufacturing process needs to use metal raw materials to prepare metal slurry for hole filling operation, so that the metal raw materials need to be resistant to the temperature of over 800 ℃. In the prior art, generally, metal raw materials which can resist the temperature of over 800 ℃ have poor electric conductivity and heat conductivity, and are easy to influence signal transmission, and in addition, the materials have certain deformation and shrinkage after being sintered, so that the size and the precision are poor.

Therefore, a new technical solution is needed to solve the above problems.

Disclosure of Invention

In view of the above, the present invention provides a multi-layer board and a method for manufacturing the same, wherein the multi-layer board adopts a ceramic substrate with a laminated hierarchical structure, and the gaps between the circuit layers on the opposite sides of the adjacent ceramic substrates are respectively filled with a filler, so as to prevent the occurrence of dark cracks due to gaps between the adjacent substrates; meanwhile, the ceramic substrate is a DPC ceramic substrate, and then a multi-layer supporting structure is formed by adopting polishing and cold welding low-temperature process technology, so that the problem of substrate shrinkage is reduced, and the precision and the reliability of the product are improved.

In order to achieve the purpose, the invention adopts the following technical scheme:

a multilayer board comprises a plurality of ceramic substrates, wherein circuit layers are respectively formed on the surfaces of the two opposite sides of each ceramic substrate, the two circuit layers of the ceramic substrates are in conduction connection through holes, and the ceramic substrates are positioned and stacked;

the ceramic substrate is a DPC ceramic substrate, the gaps of the circuit layers on the opposite sides of the adjacent ceramic substrates are respectively provided with a filler, and the outer surfaces of the fillers and the surface of the metal base material on the outer side of the circuit layer are both polishing surfaces which are arranged in a flush manner to form polishing stacking surfaces of the ceramic substrates; the polishing stacking surfaces of the adjacent ceramic substrates are oppositely overlapped up and down and are fixedly bonded by cold welding, and the metal base materials on the outer side of the circuit layer on one opposite side of the adjacent ceramic substrates are bonded together.

Preferably, the polished surface has a surface roughness of less than 0.05 microns.

Preferably, the filler is an insulating filler.

Preferably, the filler fills the gap between the circuit layers on the opposite sides of the adjacent ceramic substrates.

Preferably, the metal substrate is copper, silver, aluminum, gold, tungsten, nickel or iron.

Preferably, the filler is a mixture of insulating powder and a curing agent.

A manufacturing method of a multilayer board comprises the following steps:

step 1: manufacturing more than two polished circuit boards, wherein the manufacturing steps of each polished circuit board comprise: step 1-1: manufacturing a ceramic substrate by adopting a DPC technology; step 1-2: filling the filler into a gap formed between circuit layers of the ceramic substrate, and after the filler is solidified, carrying out surface treatment on the surface of the ceramic substrate to form a polished circuit board;

step 2: the polishing overlapping surfaces of more than two polishing circuit boards are oppositely overlapped through CCD positioning, and the polishing circuit boards which are overlapped are exhausted;

and step 3: and bonding the adjacent polishing overlapping surfaces of the overlapped polishing circuit boards together by a cold welding method, so that the metal base materials on the outer sides of the circuit layers on the opposite sides of the adjacent ceramic substrates are bonded together.

In a preferred embodiment, in the step 1-2, the insulating powder and the curing agent are mixed as a filler, the filler is stirred into slurry, and the slurry filler is applied to the surface of the ceramic substrate.

Preferably, in step 1-2, the surface of the ceramic substrate is polished to expose the metal base material of the circuit layer, and then the outer surface of the ceramic substrate is polished to form the polished circuit board.

Preferably, in step 1-2, the gap formed between the circuit layers of the ceramic substrate is filled with a filler.

Compared with the prior art, the invention has obvious advantages and beneficial effects, and concretely, according to the technical scheme, the metal base material and the ceramic substrate are bonded by the multi-layer board through a cold welding method, and the filler is respectively arranged in the gaps of the circuit layers on the opposite sides of the adjacent ceramic substrates of the multi-layer board, and plays a supporting role on the adjacent ceramic substrates respectively, so that the dark crack caused by the gap between the adjacent substrates is avoided.

Secondly, the ceramic substrate of the multilayer board is a DPC ceramic substrate, a circuit pattern is manufactured by adopting a DPC process, then a multilayer supporting structure is formed by adopting polishing and cold welding technologies, the shrinkage problem of the substrate is reduced, and the precision of the multilayer circuit board is improved. The DPC ceramic substrate adopts a low-temperature process, so that adverse effects of high temperature on materials or circuit structures are avoided, and the manufacturing process cost is reduced. In addition, the polishing and cold welding process also adopts a low-temperature process, and copper, silver, aluminum and other metals with better conductivity can be selected as a signal transmission line, so that the adverse effect on the signal transmission is reduced.

To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Drawings

FIG. 1 is a hierarchical structure diagram of a first embodiment of the present invention;

FIG. 2 is a hierarchical structure diagram of a second embodiment of the present invention;

FIG. 3 is a flowchart of a method of fabricating a first embodiment of the present invention;

FIG. 4 is a flowchart of a manufacturing method according to a second embodiment of the present invention.

The attached drawings indicate the following:

100. first ceramic substrate 101, first polished surface

110. Second ceramic substrate 111, second polished surface

120. Third ceramic substrate 121, third polished surface

122. Fourth polished surface 11, first circuit layer

12. Second circuit layer 13, via hole

14. Gap 20, filler.

Detailed Description

Referring to fig. 1 to 4, specific structures and manufacturing method flow charts of two embodiments of the present invention are shown.

A multilayer board comprises a plurality of ceramic substrates, wherein two opposite side surfaces of the ceramic substrates are respectively provided with a circuit layer; and the two circuit layers form a conductive connection through the through hole 13; wherein, a plurality of ceramic substrates are sequentially overlapped and bonded. The ceramic substrate is a DPC ceramic substrate, namely: the ceramic substrate is a circuit substrate manufactured by adopting a DPC technology, the DPC technology adopts a low-temperature process, the process adopts a temperature below 300 ℃, adverse effects on materials or circuit structures caused by high temperature are avoided, the manufacturing process cost is reduced, and the DPC technology adopts a film and photoetching development technology, so that: the metal circuit on the ceramic substrate is finer, the surface roughness is lower than 0.3 micron, the alignment precision error of the circuit layer of the ceramic substrate is small, and the ceramic substrate is suitable for packaging electronic devices with higher alignment precision requirements.

The fillers 20 are respectively disposed between the adjacent ceramic substrates. Preferably, the filler 20 is a mixture of insulating powder and a curing agent, wherein the insulating powder is resin powder. Specifically, the filler 20 is provided in each of the gaps 14 of the wiring layers on the opposite sides of the adjacent ceramic substrates. The filler 20 is flush with the metal base material outside the circuit layer, and forms the outer surface of the ceramic substrate. The outer surfaces of the opposite sides of the adjacent ceramic substrates are both provided with polishing surfaces, specifically, the outer surfaces of the fillers and the surfaces of the metal base materials outside the circuit layer are both polishing surfaces which are arranged in parallel and level, so that polishing superposed surfaces of the ceramic substrates are formed; and the polishing overlapping surfaces of the adjacent ceramic substrates are oppositely overlapped up and down and are fixedly bonded by cold welding, and the metal base materials on the outer sides of the circuit layers on the opposite sides of the adjacent ceramic substrates are bonded together. Preferably, the polishing surface has a surface roughness of less than 0.05 microns. Preferably, the metal substrate is copper, silver, aluminum, gold, tungsten, nickel or iron, and in practice, other metals with good conductivity may be used as the metal substrate.

Fig. 1 is a diagram showing a hierarchical structure of the first embodiment, and the first embodiment shows a multilayer board having a two-layer structure. In a first embodiment, the multilayer board comprises two ceramic substrates stacked one on top of the other: a first ceramic substrate 100 and a second ceramic substrate 110. The upper surface of the ceramic substrate is provided with a first circuit layer 11, the lower surface of the ceramic substrate is provided with a second circuit layer 12, and the second circuit layer 12 is in conductive connection with the first circuit layer 11 through a through hole 13. The second circuit layer 12 of the first ceramic substrate 100 and the first circuit layer 11 of the second ceramic substrate 110 are oppositely arranged; the filler 20 is provided on each of the second circuit layer 12 of the first ceramic substrate 100 and the first circuit layer 11 of the second ceramic substrate 110. The filler 20 fills the gap 14 of the second circuit layer 12 of the first ceramic substrate 100 and the gap 14 formed by the first circuit layer 11 of the second ceramic substrate 110, respectively, so that: the filler 20 forms a support between the adjacent first and second ceramic substrates 100 and 110. In addition, the filler 20 is flush with the metal base material outside the second circuit layer 12 of the first ceramic substrate 100, and forms the outer surface of the first ceramic substrate 100; the filler 20 is flush with the metal base material outside the first circuit layer 11 of the second ceramic substrate 110, and forms an outer surface of the second ceramic substrate 110. The outer surface of the first ceramic substrate 100 is provided with a first polishing surface 101, correspondingly, the outer surface of the second ceramic substrate 110 is provided with a second polishing surface 111, the first polishing surface 101 and the second polishing surface 111 are arranged in an up-down opposite overlapping manner, and the first ceramic substrate 100 and the second ceramic substrate 110 are bonded by a cold welding method to form a multilayer board with a double-layer structure.

Fig. 2 shows a hierarchical structure diagram of the second embodiment, and the second embodiment shows a multilayer board having a three-layer structure. In the second embodiment, a third ceramic substrate 120 is added to the intermediate layer of the two ceramic substrates stacked up and down, that is: the multilayer board comprises three ceramic substrates which are arranged in an up-and-down overlapping mode: a first ceramic substrate 100, a third ceramic substrate 120, and a second ceramic substrate 110. The upper surface and the lower surface of the third ceramic substrate 120 are respectively formed with: a first circuit layer 11 and a second circuit layer 12. In this embodiment, the first circuit layer 11 of the third ceramic substrate 120 is disposed opposite to the second circuit layer 12 of the first ceramic substrate 100, and the second circuit layer 12 of the third ceramic substrate 120 is disposed opposite to the first circuit layer 11 of the second ceramic substrate 110. The third ceramic substrate 120 is provided with a third polished surface 121 on the upper outer surface thereof, and a fourth polished surface 122 on the lower outer surface thereof. A first polishing surface 101 is provided on the outer surface of the first ceramic substrate 100, and a second polishing surface 111 is provided on the outer surface of the second ceramic substrate 110. The third polishing surface 121 and the first polishing surface 101 are oppositely overlapped up and down, the fourth polishing surface 122 and the second polishing surface 111 are oppositely overlapped up and down, and the first ceramic substrate 100, the third ceramic substrate 120 and the second ceramic substrate 110 are bonded by a cold welding method to form a multilayer board with a three-layer structure.

In practical implementation, the multilayer board may be a laminated structure with more than four layers.

Next, a method for manufacturing a multilayer board is described in detail, the method for manufacturing the multilayer board includes the following steps:

step 1: manufacturing more than two polished circuit boards, wherein the manufacturing steps of each polished circuit board comprise: step 1-1: manufacturing a ceramic substrate by adopting a DPC technology;

step 1-2: taking insulating powder and a curing agent as a filler 20, stirring the filler 20 into slurry, coating the slurry-like filler 20 on the surface of a ceramic substrate, filling the filler 20 in a gap 14 formed between circuit layers of the ceramic substrate, grinding the surface of the ceramic substrate after the filler 20 is solidified to expose a metal base material of the circuit layer, and polishing the outer surface of the ceramic substrate to form a polished circuit board;

step 2: the polishing surfaces of more than two polishing circuit boards are oppositely overlapped through CCD positioning, and the polishing circuit boards which are overlapped are exhausted;

and step 3: and bonding the adjacent polishing overlapping surfaces of the overlapped polishing circuit boards together by a cold welding method. The metal base materials on the outer sides of the circuit layers on the opposite sides of the adjacent ceramic substrates are bonded together.

The manufacturing method of the multilayer board can manufacture more than two layers of substrates, in the manufacturing method of the multilayer board, both the polishing process and the cold welding process adopt low-temperature processes, and copper, silver, aluminum, gold, tungsten, nickel, iron and other metals with better conductivity can be selected as metal circuit layers, so that the adverse effect on signal transmission is reduced, and meanwhile, the expansion with heat and contraction with cold of the ceramic substrate caused by the high-temperature process are avoided, therefore, the manufacturing method of the multilayer board can improve the product precision and the product reliability.

Fig. 3 is a flowchart illustrating a manufacturing method of the first embodiment, and a flowchart illustrating a manufacturing method of a multilayer board having a two-layer structure. First, the DPC technique is used to form the first and second ceramic substrates 100 and 110. Filling the filler 20 on the lower surface of the first ceramic substrate 100, and filling the filler 20 in the gap 14 formed between the circuit layers of the first ceramic substrate 100; after the filler 20 is solidified, the lower surface of the first ceramic substrate 100 is ground to expose the metal base material of the circuit layer, and then the outer surface of the first ceramic substrate 100 is polished to form a first polished circuit board. Similarly, the same method is performed on the upper surface of the second ceramic substrate 110 to form a second polished wiring board. Then, positioning through a CCD, oppositely overlapping the polishing surface of the first polishing circuit board and the polishing surface of the second polishing circuit board, and exhausting the two polishing circuit boards; and bonding the polished surfaces of the two polished circuit boards together by a cold welding method to form the multilayer board with a double-layer structure.

Fig. 4 shows a flow chart of a manufacturing method of the second embodiment, and a flow chart of a manufacturing method of a multilayer board having a multilayer structure of the second embodiment. In the second embodiment, on the basis of the first embodiment, a plurality of third ceramic substrates 120 are additionally disposed in the middle layers of the two ceramic substrates stacked up and down, that is: the multilayer board comprises a first ceramic substrate 100, a third ceramic substrate 120 and a second ceramic substrate 110 which are overlapped up and down. First, the first ceramic substrate 100, the second ceramic substrate 110, and the third ceramic substrate 120 are manufactured by the DPC technique. The first ceramic substrate 100 and the second ceramic substrate 110 are respectively ground and polished by the manufacturing method of the first embodiment to form a first polished circuit board and a second polished circuit board. Filling the filler 20 on the upper surface and the lower surface of the third ceramic substrate 120, respectively, and filling the filler 20 in the gap 14 formed between the circuit layers on the upper surface and the lower surface of the third ceramic substrate 120; after the filler 20 is solidified, the upper surface and the lower surface of the third ceramic substrate 120 are respectively ground to expose the metal base material of the circuit layer, and then two outer surfaces of the third ceramic substrate 120 are polished to form a third polished circuit board. Then, positioning through a CCD, oppositely overlapping the polishing surface of the first polishing circuit board and the upper polishing surface of the third polishing circuit board, and exhausting the two polishing circuit boards; and bonding the polished surface of the first polished circuit board and the upper polished surface of the third polished circuit board together by a cold welding method. And similarly, bonding the lower side polished surface of the third polished circuit board and the polished surface of the second polished circuit board together to form the multilayer board with the multilayer structure. In actual manufacturing, the first polished circuit board, the second polished circuit board and the third polished circuit board can be overlapped and then cold-welded, bonded and fixed together.

The design key point of the invention is that the metal base material and the ceramic substrate are bonded by the multi-layer board by adopting a cold welding method, and the filler is respectively arranged in the gap of the circuit layer on the opposite side of the adjacent ceramic substrate of the multi-layer board, and the filler respectively plays a supporting role for the adjacent ceramic substrate, thereby avoiding the dark crack caused by the gap between the adjacent substrates.

Secondly, the ceramic substrate of the multilayer board is a DPC ceramic substrate, a circuit pattern is manufactured by adopting a DPC process, then a multilayer supporting structure is formed by adopting polishing and cold welding technologies, the shrinkage problem of the substrate is reduced, and the precision of the multilayer circuit board is improved. The DPC ceramic substrate adopts a low-temperature process, so that adverse effects of high temperature on materials or circuit structures are avoided, and the manufacturing process cost is reduced. In addition, the polishing and cold welding process also adopts a low-temperature process, and copper, silver, aluminum and other metals with better conductivity can be selected as a signal transmission line, so that the adverse effect on the signal transmission is reduced.