CN113950206A

CN113950206A - 5G multilayer LCP material substrate and processing method thereof

Info

Publication number: CN113950206A
Application number: CN202111560803.9A
Authority: CN
Inventors: 谈兴; 虞成城; 李绪东; 朱秋荣
Original assignee: Shenzhen Sunway Communication Co Ltd
Current assignee: Shenzhen Sunway Communication Co Ltd
Priority date: 2021-12-20
Filing date: 2021-12-20
Publication date: 2022-01-18
Anticipated expiration: 2041-12-20
Also published as: CN113950206B

Abstract

The invention relates to the technical field of circuit boards, in particular to a 5G multilayer LCP material substrate and a processing method thereof, which comprises the following steps: s1, forming a first substrate, wherein the first substrate comprises an LCP core layer, and copper layers and UV (ultraviolet) adhesive reducing films which are respectively arranged on two sides of the LCP core layer; s2, performing UV laser punching on the UV adhesive reducing film, wherein the hole extends to the surface of the copper layer; s3, after tearing off the dark PET film, printing conductive paste; s4, tearing off the UV adhesive reducing film from the LCP core layer under the irradiation of UV light with the same wavelength as UV laser to obtain a second substrate, wherein the surface of the second substrate is provided with salient points formed by the conductive slurry; s5, forming a 5G multilayer LCP material substrate, wherein the 5G multilayer LCP material substrate is formed by mutually conducting and pressing a plurality of second substrates through the bumps. The processing method of the 5G multilayer LCP material substrate provided by the invention can effectively improve the yield of finished products.

Description

5G multilayer LCP material substrate and processing method thereof

Technical Field

The invention relates to the technical field of circuit boards, in particular to a 5G multilayer LCP material substrate and a processing method thereof.

Background

In the existing LCP multilayer circuit board processing technology, in order to improve the precision of the LCP surface, a mode of attaching a layer of silica gel series PET film to the LCP surface is generally adopted for processing, and specifically, see fig. 1. The holes are processed on the surface of the silica gel series PET film, then the conductive slurry is printed on the surface of the silica gel series PET film, finally, the silica gel series PET film is torn off, and then salient points formed by the conductive slurry can be formed in the holes, and at the moment, the multilayer LCP plates can be connected with each other and conducted with each other through the salient points. However, in the actual processing process, if the silicone series PET film is too thin, the problem that the whole roll is not easy to be processed in the laminating process, and the film is easy to be stretched to influence the expansion and shrinkage of the product is solved, and the silicone series PET film is required to have the requirement of high release gram weight in the processing process, so that the silicone series PET film and the LCP substrate are not easy to separate in the process of manufacturing the process, but the silicone series PET film with low release gram weight is more convenient for the film tearing operation in the automatic processing process, but the film is too thin or the silicone series PET film with too high release gram weight is easier to tear. Therefore, how to balance the relationship between the film thickness and the release force gram weight in the actual production process so as to facilitate better production and processing and improve the product yield is a technical problem that production technicians are difficult to overcome. Simultaneously, current silica gel series PET is because its from the type power grammes per square metre at 30~60g when using, leads to it to tear to leave the back and have a large amount of silica gel to remain on the LCP surface, need handle through extra washing step, seriously extension production cycle and product quality.

Disclosure of Invention

In order to overcome the defects of the prior art, the technical problems to be solved by the invention are as follows: the processing method of the 5G multilayer LCP material substrate and the 5G multilayer LCP material substrate prepared by the processing method can effectively improve the product yield.

In order to solve the technical problem, the invention provides a processing method of a 5G multilayer LCP material substrate, which comprises the following steps:

s1, forming a first substrate, wherein the first substrate comprises an LCP core layer, copper layers and UV (ultraviolet) anti-adhesion films, the copper layers and the UV anti-adhesion films are respectively arranged on two sides of the LCP core layer, the UV anti-adhesion films comprise a dark PET film, a silica gel layer, a transparent PET film and a UV adhesive layer which are sequentially stacked from the surface to the inside, and the UV adhesive layer is attached to the surface of the LCP core layer;

s2, performing UV laser punching on the UV adhesive reducing film, wherein the hole extends to the surface of the copper layer;

s3, after tearing off the dark PET film, printing conductive paste;

s4, tearing off the UV adhesive reducing film from the LCP core layer under the irradiation of UV light with the same wavelength as UV laser to obtain a second substrate, wherein the surface of the second substrate is provided with salient points formed by the conductive slurry;

s5, forming a 5G multilayer LCP material substrate, wherein the 5G multilayer LCP material substrate is formed by mutually conducting and pressing a plurality of second substrates through the bumps.

Further provides a processing method of the 5G multilayer LCP material substrate prepared by the processing method of the 5G multilayer LCP material substrate.

The invention has the beneficial effects that: the UV viscosity-reducing film is formed by mutually bonding double-layer PET films, so that the whole thickness is high, and an effective supporting effect can be achieved, so that the problem that when the UV viscosity-reducing film is attached to LCP, the product is subjected to expansion and shrinkage deformation in the production process due to the fact that the whole thickness of the UV viscosity-reducing film is too thin is solved; meanwhile, after UV irradiation, the UV adhesive layer can be quickly de-adhered until the weight of the release force gram is only about 5g, so that an operator can conveniently tear off the UV adhesive layer; the PET film on the surface of the UV-reducing film is dark, namely, opaque materials are selected, so that the UV-reducing film can be effectively prevented from being subjected to viscosity reduction in the production process in advance, and the viscosity reduction in the holes can lead to conductive slurry diffusion, and further the risk of short circuit of the 5G multi-layer LCP material substrate after press-forming can be caused.

Drawings

FIG. 1 is a flow chart of a conventional LCP multi-layer circuit board processing method in the background art of the present invention;

FIG. 2 is a schematic diagram illustrating the structure of a UV adhesive reducing film according to an embodiment of the present invention;

FIG. 3 is a flow chart showing a method of processing a 5G multi-layer LCP material substrate according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a defective product according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of another defective product according to an embodiment of the invention.

Description of reference numerals: 1. a copper layer; 2. LCP core layer; 3. a silica gel series PET film; 4. conductive paste; 5. UV film reduction; 51. a dark PET film; 52. a silica gel layer; 53. a transparent PET film; 54. a UV adhesive layer; 6. a gap.

Detailed Description

In order to explain technical contents, achieved objects, and effects of the present invention in detail, the following description is made with reference to the accompanying drawings in combination with the embodiments.

Referring to fig. 3, a method for processing a 5G multilayer LCP material substrate includes the following steps:

s1, forming a first substrate, wherein the first substrate comprises an LCP core layer 2, and copper layers 1 and UV anti-adhesion films 5 respectively arranged on two sides of the LCP core layer 2, the UV anti-adhesion films 5 comprise a dark PET film 51, a silica gel layer 52, a transparent PET film 53 and a UV adhesive layer 54 which are sequentially stacked from the surface to the inside, and the UV adhesive layer 54 is attached to the surface of the LCP core layer 2;

s2, carrying out UV laser punching on the UV adhesive reducing film 5, wherein the hole extends to the surface of the copper layer 1;

s3, after tearing off the dark PET film 51, printing the conductive paste 4;

The structure of the UV anti-adhesive film is shown in FIG. 2, and the UV anti-adhesive film comprises a dark PET film 51 from the surface to the inside, a silica gel layer 52, a transparent PET film 53 and a UV adhesive layer 54. The dark-color PET film 51 is used for blocking UV, so that bubbles generated by viscosity reduction of the UV adhesive layer around the holes in advance due to the irradiation of UV light in the UV laser process are avoided, and the permeation of the conductive paste from gaps generated by viscosity reduction of the UV adhesive layer in the holes in the subsequent conductive paste printing process is avoided, and the specific reference is shown in FIG. 4. Fig. 4 shows a schematic structural diagram of the existing UV adhesive reducing film (without the surface dark PET film) after UV laser and printing, and shows a process that the UV adhesive layer 54 around the hole after UV laser punching is subjected to advanced irradiation of UV light, so that advanced adhesive reducing is caused and a gap 6 is generated, and a process that the conductive paste penetrates from the gap 6 after the conductive paste 4 is printed.

Preferably, the wavelength of the UV light irradiated by the UV laser and the UV light is 365 nm. Therefore, it should be understood that the color of the dark PET film in the present invention may be any color that can prevent the 365nm UV light from transmitting or can effectively absorb the 365nm UV light, and the like, which is suitable for the present technical solution. More preferably, the dark PET film is black in color.

Evenly punch at UV visbreaking membrane surface through UV radium-shine, the hole extends to the surface of copper layer, should understand, the surface of copper layer is the one side that the copper layer contacted with LCP sandwich layer to make through conductive paste be in downthehole bump formation, and through when the bump carries out a plurality of second base plates and carries out interconnect, accessible conductive paste switches on copper layer and adjacent copper layer each other.

Preferably, after the dark PET film is torn off, the thickness of the UV adhesive reducing film is 17.5-20.5 microns.

Illustratively, in one embodiment, the thickness of the dark PET film and the thickness of the transparent PET film are both 12.5 μm, the thickness of the silica gel layer is 5-8 μm, and the thickness of the UV adhesive layer is 5-8 μm. It should be noted that, in the industry at present, the thickness of PET is only 12.5 μm and 25 μm, so that 12.5 μm PET is selected as an alternative of the present application, which can facilitate the control of the height of the formed bumps, but the thickness of the UV anti-adhesive film is 17.5 to 20.5 μm after the PET film is finally torn off by customizing the PET film with the thickness of 12.5 to 25 μm, which is also applicable to the present technical solution. Meanwhile, it should be noted that, when the dark-color PET film is torn off, the silica gel layer is completely torn off from the transparent PET film or only a small part of the silica gel layer remains, so that after the dark-color PET film is torn off, the thickness of the UV-reduced adhesive film is the average thickness of the UV adhesive layer, the transparent PET film and the part of the silica gel layer.

The bump height h is 10-25 μm, preferably 17.5-20.5 μm, so as to avoid the problems of conductive paste diffusion, short circuit and the like caused by overhigh bump height h in the pressing process. Specifically, referring to fig. 5, fig. 5 shows a schematic structural diagram of a defective product when the bumps are too high, and it can be seen from the diagram that after the bumps are pressed, the excessive conductive paste is diffused to the adjacent patterned copper layer after the bumps are pressed due to the too high bumps, thereby causing a short circuit problem.

Illustratively, the pressing condition is high temperature range to 300 ℃, pressure 10 to 20kg and time 30 min.

Furthermore, the overall thickness of the UV adhesive reducing film is 35-41 mu m. Under this thickness, the UV subtracts the effect that the mucosa can effectively play the support to avoid because the UV subtracts the mucosa film thin leads to whole roll of laminating process difficult processing and UV subtracts the easy emergence that influences product harmomegathus scheduling problem of gluing film by tensile. Note that the overall thickness should be understood as the thickness of the UV adhesion reducing film when the dark PET film is not peeled off, that is, the thickness of the UV adhesion reducing film at steps S1 and S2.

Furthermore, the release force gram weight of the dark color PET film is 20-24 g. The dark PET film can be conveniently torn off from the transparent PET film in the production process under the gram weight of the release force. The release force grammage of the dark PET film is understood to be the release force required for the dark PET film to tear from the transparent PET film.

Preferably, the overall release gram weight of the UV viscosity-reducing film is 600-800 g, and the overall release gram weight after viscosity reduction is less than 20g, preferably 5 g. The overall release force gram weight of the UV adhesive reducing film can reach 600-800 g when the UV adhesive reducing film is not subjected to adhesive reducing, so that the UV adhesive reducing film can be effectively prevented from being separated in advance in the production and processing process under the high release force gram weight, and the high adhesion between the UV adhesive reducing film and the LCP core layer is ensured; however, after the UV subtracts the mucosa and receives UV light irradiation, the rapid visbreaking of UV glue film makes the whole of UV subtract mucosa about 5g from the type grammes per square metre, and operating personnel or automated equipment of being convenient for tear UV subtract the mucosa from LCP sandwich layer. The overall peel grammage is understood to mean the peel grammage of the UV-vis-a-vis film peeled off entirely from the surface of the LCP core layer, and also to mean the peel force required to peel the transparent PET film off from the LCP core layer.

Preferably, the method further comprises S0, and forming a pattern on the surface of the copper layer. The construction method of the pattern is any one of the existing copper layer pattern construction methods.

Specifically, S5 is: and adhering at least two second substrates in the bump alignment mode, and/or adhering at least two second substrates on the surface of the copper layer in the bump alignment mode, and pressing to form the 5G multilayer LCP material substrate.

Specifically, referring to fig. 3G or 3h, 3G shows a schematic structural diagram of the 5G multilayer LCP material substrate after being connected by the bumps; and 3h, showing a structural schematic diagram of the 5G multi-layer LCP material substrate which is formed by high-temperature pressing after the salient points are connected. As can be seen from the figure, the first layer second substrate l1 and the second layer second substrate l2 are connected with each other through bumps and bumps, so that the interconnection and conduction of two adjacent copper layers are realized; the third layer second substrate l3 directly contacts the copper layer of the second layer second substrate l2 through bumps to realize the interconnection and conduction between the copper layer of the third layer second substrate l3 and the copper layer of the second layer second substrate l 2.

The 5G multilayer LCP material substrate is prepared by the processing method of the 5G multilayer LCP material substrate.

Example 1

A processing method of a 5G multi-layer LCP material substrate comprises the following steps:

s0, constructing a pattern on the copper layer on one surface of the LCP core layer;

s1, attaching a UV (ultraviolet) adhesive reducing film (lnfu 1205, available from Lenen, with the overall thickness of 41 mu m, the thickness of 20.5 mu m after the black PET film is torn off, and other parameters are described in the table 1) to one surface, away from the copper layer, of the LCP core layer;

s2, performing UV laser punching on a UV adhesive reducing film at the wavelength of 400MJ/cm2 and 365nm, wherein the hole extends to the surface of the copper layer;

s3, after tearing off the black PET film on the surface of the UV anti-adhesive film, printing conductive paste;

s4, tearing off the UV adhesive reducing film from the LCP core layer under the irradiation of UV light with the wavelength of 365nm to obtain a second substrate, wherein the surface of the second substrate is provided with salient points formed by conductive paste, and the height of the salient points is approximately about 20.5 microns;

s5, aligning and bonding the bumps of the first layer second substrate l1 and the second layer second substrate l 2;

s6, aligning and bonding the bumps of the third layer second substrate l3 with the copper layer of the second layer substrate l 2;

and S7, repeating S6 for multiple times, and laminating the multilayer second substrate under the conditions that the temperature is about 300 ℃, the pressure is 15kg and the running time is 30min at a high-temperature section to form the 5G multilayer LCP material substrate.

TABLE 1

Example 2

A processing method of a 5G multi-layer LCP material substrate is different from the embodiment 1 in that: the overall thickness of the UV-adhesive film was 35 μm, the thickness after peeling off the black PET film was 17.5 μm, and the bump height was approximately 17.5 μm.

Comparative example 1

A processing method of a 5G multi-layer LCP material substrate is different from the embodiment 1 in that: a commercially available conventional UV-reduced film (trade name Lnu2508, no black PET film on the surface) was used.

Comparative example 2

A processing method of a 5G multi-layer LCP material substrate is different from the embodiment 1 in that: a conventional silicone-based PET film (brand LNS 5020) was used.

Example of detection

The 5G multilayer LCP material substrates obtained in example 1, comparative example 1 and comparative example 2 were subjected to yield tests, with the test standards: testing the resistance; the test results are shown in table 2.

TABLE 2

As can be seen from table 2, the yield of the 5G multilayer LCP material substrate can be effectively improved by using the UV-adhesive reducing film (lnfu 1205). Meanwhile, it is important to explain that the surface of the comparative example 1 is not protected by a black PET film, so that after laser punching, the UV anti-adhesion film is separated in advance, the forming of the salient points in the holes and the height control of the salient points are seriously influenced, and more operations on the anti-adhesion first substrate are difficult to perform.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent changes made by using the contents of the present specification and the drawings, or applied directly or indirectly to the related technical fields, are included in the scope of the present invention.

Claims

1. A processing method of a 5G multi-layer LCP material substrate is characterized by comprising the following steps:

s3, after tearing off the dark PET film, printing conductive paste;

2. The method for processing the 5G multi-layer LCP material substrate according to claim 1, wherein the thickness of the UV adhesive reducing film after the dark PET film is peeled is 17.5-20.5 μm.

3. The method for processing the 5G multi-layer LCP material substrate according to claim 1, wherein the UV adhesive reducing film has an overall thickness of 35-41 μm.

4. The processing method of the 5G multi-layer LCP material substrate as claimed in claim 1, wherein the release gram weight of the dark PET film is 20-24G.

5. The processing method of the 5G multi-layer LCP material substrate as claimed in claim 1, wherein the UV de-bonding film has an overall releasing force gram weight of 600-800G, and the overall releasing force gram weight after de-bonding is less than 20G.

6. The method for processing a 5G multi-layer LCP material substrate as claimed in claim 1, further comprising S0, forming a pattern on the surface of the copper layer.

7. The method for processing a substrate of 5G multi-layer LCP material as claimed in claim 1, wherein said S5 is: and adhering at least two second substrates in the bump alignment mode, and/or adhering at least two second substrates on the surface of the copper layer in the bump alignment mode, and pressing to form the 5G multilayer LCP material substrate.

8. The 5G multi-layer LCP material substrate prepared by the processing method of the 5G multi-layer LCP material substrate as claimed in any one of claims 1 to 7.