TWM556457U - Flexible gum-coating copper foil substrate having composite lamination structure - Google Patents

Abstract

A flexible coated copper foil substrate having a composite stack comprising, in order from top to bottom, a low profile copper foil layer, an upper dielectric adhesive layer, a core layer, a lower dielectric adhesive layer and a release layer, wherein the core layer It is a polyimide film, the low profile copper foil layer is a copper foil layer with an Rz value of 0.4 to 1.0 μm, and the bonding strength of the low profile copper foil layer, the upper dielectric adhesive layer, the core layer and the lower dielectric layer is formed. >0.7 kgf/cm and a water absorption of 0.01% to 1.5%. Therefore, the flexible coated copper foil substrate of the present invention has good electrical properties, high-speed transmission, low thermal expansion coefficient, stable Dk/Df performance under high temperature and humidity environment, ultra-low water absorption rate, and good UV laser drilling capability. Low rebound force for high density assembly and excellent mechanical properties.

Description

Flexible coated copper foil substrate with composite stack

The present invention relates to a flexible coated copper foil substrate for a flexible circuit board and a preparation thereof, and more particularly to a low dielectric loss flexible coated copper foil substrate having a composite stack.

With the rapid development of information technology, in order to meet the high-speed transmission of signal transmission, rapid heat dissipation and heat conduction, and the lowest production cost, the design and application of various forms of mixed-pressure structure multi-layer boards have emerged. Printed circuit boards (PCBs) are indispensable materials in electronic products, and as the demand for consumer electronics increases, so does the demand for printed circuit boards. Because flexible printed circuit boards (FPC) have the characteristics of flexibility and three-dimensional space wiring, under the development trend of technology-based electronic products that emphasize lightness, shortness, flexibility, and high frequency, It is currently widely used in computers and peripherals, communication products, and consumer electronics.

In the high-frequency world, wireless infrastructure needs to provide a sufficiently low Insertion loss to effectively improve energy efficiency. With the accelerated development of 5G communication, millimeter wave, and aerospace military, high-frequency and high-speed FPC/PCB demand is coming. With the rise of emerging industries such as big data and Internet of Things and the popularity of mobile interconnection terminals, it is fast to process and transmit information. Become a communications industry Focus. In the field of communication, the future 5G network has a higher speed bandwidth and more dense micro base station construction than 4G, and the network speed is faster. In response to the demand for Internet of Things and cloud computing and broadband communication in the new era, the development of high-speed servers and higher transmission rate mobile phones has become a market trend. In general, FPC/PCB is the main bottleneck in the entire transmission process. If there is a lack of good design and electrical related materials, the transmission rate will be seriously delayed or the signal loss will be caused. This puts high demands on the board material. In addition, the high-frequency substrates currently used in the industry are mainly liquid crystal polymer (LCP) plates and polytetrafluoroethylene (PTFE) fiber sheets, but they are also limited by process technology, such as manufacturing equipment. The requirements are high and need to be operated in a higher temperature environment (> 280 ° C), which in turn causes uneven film thickness and does not easily control the impedance of the board. In addition, there are problems such as the inability to use the fast press equipment, resulting in difficult processing.

The general epoxy resin products are not ideal in the small-aperture (<100μm) ultraviolet (UV) laser processing of the downstream industry. It is easy to cause the through hole (PTH, Plating Through Hole) to be retracted, which is only suitable for use. The method of mechanical drilling of large apertures has poor process adaptability.

In addition, the current Bond Ply product is used in the downstream industry to peel off the release layer and then press the copper foil, but using a flexible coated copper foil substrate (FRCC, Flexible Resin Coated Copper). It can save downstream processing and directly match other LCP boards or polyimine (PI, Polyimide) double panels.

In order to make up for the above deficiencies, the present invention provides a low dielectric loss FRCC substrate with a composite stack, which not only has good electrical properties, but also has high-speed transmission, low thermal expansion coefficient, and stable Dk/Df performance in high temperature and humidity environments. Ultra-low water absorption, good UV laser drilling capability, low resilience for high-density assembly and excellent mechanical properties. In addition, the current coating technique can only apply a thickness of about 50 μm at most, but the manufacturing method of the present invention can easily obtain a thick film of 100 μm or more.

In order to solve the foregoing technical problems, the present invention provides a low dielectric loss FRCC substrate having a composite stack, comprising: a core layer having a relatively upper surface and a lower surface, and the material forming the core layer is a polysilicon An imide; an upper dielectric layer and a lower dielectric layer, wherein the upper dielectric layer and the lower dielectric layer are respectively formed on the upper surface and the lower surface of the core layer; the low profile copper foil layer is formed On the upper dielectric layer, the upper dielectric layer is sandwiched between the core layer and the low profile copper foil layer; and the release layer is formed on the lower dielectric layer to make the lower dielectric layer An electro-adhesive layer is sandwiched between the core layer and the release layer.

In addition, in a specific embodiment, the low profile copper foil layer has a surface roughness Rz value of 0.4 to 1.0 μm, and the low profile copper foil layer is a rolled copper foil layer or an electrolytic copper foil layer.

In one embodiment, the core layer has a thickness of 5 to 50 μm; the upper dielectric layer and the lower dielectric layer have a thickness of 2 to 50 μm.

In a specific embodiment, the low profile copper foil layer has a thickness of 1 to 35 μm.

Further, preferably, the core layer has a thickness of 5 to 12.5 μm. More preferably, the core layer has a thickness of 5 to 7.5 μm.

In one embodiment, the upper dielectric layer and the lower dielectric layer are both thermosetting polyimine resin layers.

In a specific embodiment, the release layer is a release film or a release paper.

In one embodiment, the low profile copper foil layer, the upper dielectric adhesive layer, the core layer, and the lower dielectric adhesive layer have a stacking strength of >0.7 kgf/cm and a water absorption of 0.01 to 1.5%.

In one embodiment, the Dk (dielectric constant) values of the upper dielectric layer and the lower dielectric layer are between 2.0 and 3.0 (10 GHz), and the Df (dielectric loss factor) value is interposed. It is between 0.002 and 0.010 (10 GHz).

According to this creation, at least the following advantages are:

First, because this creation uses a low profile copper foil layer, an upper dielectric adhesive layer, a core layer, a lower dielectric adhesive layer and a release layer from top to bottom, compared to the traditional Bond Ply products in the downstream industry. When using, it is necessary to peel off the release layer and then press the copper foil layer. After the separation of the release layer, it can be directly used with other LCP boards or PI double panels. It does not need to add a layer of pure glue for bonding, saving downstream. The processing process further saves production costs and improves production efficiency.

Second, the creation uses a low profile copper foil layer, which has a skin effect during signal transmission. Due to the low surface roughness of the low profile copper foil, fine crystals and good surface flatness, the signal can achieve high speed transmission. At the same time, the upper and lower dielectric layers have lower and stable Dk/Df performance, which can reduce the loss during signal transmission, further improve the signal transmission quality, and are fully capable of FPC high-speed high-speed, heat dissipation and heat conduction rapid production and production. The need to minimize the cost of development.

3. The Dk value of the upper and lower dielectric layers in this creation is 2.0 to 3.0 (10G). Hz), Df value is 0.002 to 0.010 (10G Hz), and has a stable Dk/Df value in high temperature and high humidity environment, making this creation suitable for low temperature (less than 180 ° C) rapid press, processability, and The requirements for the production equipment are low, thereby reducing the production cost, and the equipment operability and processability are superior to the existing LCP substrate and PTFE fiber board. More preferably, the risk of line oxidation during the preparation of the FPC is greatly reduced due to the low temperature press fit.

4. Since the core layer of the creation is a polyimide film, the upper and lower dielectric layers are polyimine layers, so the creation is more suitable for the downstream industry than the traditional epoxy resin products. Aperture (<100μm) UV laser processing, it is not easy to cause PTH (Plating Through Hole) or hole retraction, uniform film thickness during pressing, good impedance control, not only suitable for machining with large bore diameter mechanical drilling The way, the process adaptability is strong.

5. This creation has a lower rebound force than the LCP board, which is only about half of the rebound force of the LCP board, and is suitable for the downstream high-density assembly process.

6. The core layer of the creation is a polyimide film, and the upper and lower dielectric layers are polyamidene resin layers. Since the polyimide resin has low water absorption, the overall water absorption of the present invention From 0.01 to 1.5%, due to the ultra-low water absorption rate, the performance after water absorption is stable and has better electrical properties.

7. The creation also has the advantages of good thermal expansion, good flexibility, high solder resistance and excellent mechanical properties, and the subsequent strength is >0.7kgf/cm, and then the strength is good.

The above description of the present invention is merely an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present creation, and can be implemented in accordance with the contents of the specification, the following is a detailed description of the preferred embodiment of the present invention. The description is as follows.

100‧‧‧Low profile copper foil layer

200‧‧‧Upper dielectric layer

300‧‧ ‧ core layer

400‧‧‧ Lower dielectric layer

500‧‧‧ release layer

Figure 1 is a schematic diagram of the structure of the creation.

The specific embodiments of the present invention are described below by way of specific embodiments, and those skilled in the art can easily understand the advantages and effects of the present invention from the contents disclosed in the present specification. This creation can also be implemented in a variety of different ways, that is, different modifications and changes can be made without departing from the scope of the present disclosure.

Embodiment: A low dielectric loss FRCC substrate having a composite stack

As shown in FIG. 1, the low dielectric loss FRCC substrate having a composite stack includes: a core layer 300, which is a polyimide film; and a dielectric layer having two layers and respectively a dielectric adhesive layer 200 and a lower dielectric adhesive layer 400, the upper dielectric adhesive layer 200 and the lower dielectric adhesive layer 400 are respectively formed on the upper and lower surfaces of the core layer 300; the low profile copper foil layer 100 is formed on the dielectric layer The upper surface of the upper dielectric layer 200, and the upper dielectric layer 200 is bonded to the core layer 300 and the low profile copper foil layer 100; and the release layer 500 is formed on the lower dielectric layer 400. The lower surface, and the lower dielectric layer 400 is bonded to the core layer 300 and the release layer 500.

The upper dielectric adhesive layer 200 and the lower dielectric adhesive layer 400 have a Dk (dielectric constant) value between 2.0 and 3.0 (10 GHz), and Df (dielectric loss factor). A very low dielectric bond layer with a value between 0.002 and 0.010 (10 GHz).

Preferably, the upper dielectric adhesive layer 200 and the lower dielectric adhesive layer 400 are extremely low dielectric adhesive layers having a Dk value between 2.3 and 3.0 (10 GHz).

The low profile copper foil layer 100 is a copper foil layer having an Rz value of 0.4 to 1.0 μm, and the low profile copper foil layer 100 is a rolled copper foil layer (RA) or an electrolytic copper foil layer (ED).

Preferably, the low profile copper foil layer is a rolled copper foil layer, more preferably a HA or HAV2 product of Nippon Mining & Metal Co., Ltd.

The core layer 300 has a thickness of 5 to 50 μm; the upper dielectric adhesive layer 200 and the lower dielectric adhesive layer 400 have a thickness of 2 to 50 μm; and the low profile copper foil layer 100 has a thickness of 1 to 35 μm.

Preferably, the core layer 300 has a thickness of 5 to 12.5 μm; the upper dielectric adhesive layer 200 and the lower dielectric adhesive layer 400 have a thickness of 10 to 50 μm; and the low profile copper foil layer 100 has a thickness of 6 to 18 μm. .

Preferably, the core layer has a thickness of 5 to 12.5 μm.

More preferably, the core layer has a thickness of 5 to 7.5 μm.

The materials of the upper dielectric adhesive layer 200 and the lower dielectric adhesive layer 400 are fluororesin, epoxy resin, acrylic resin, urethane resin, ruthenium rubber resin, and polyparaxylene resin. At least one of a bismaleimide resin and a polyamidene resin.

The upper dielectric adhesive layer 200 and the lower dielectric adhesive layer 400 are both a thermosetting polyimide-based resin adhesive layer, and the upper dielectric adhesive layer 200 and the lower dielectric adhesive layer 400 The content of the amine resin is from 30 to 90% by weight.

The release layer 500 is a release film or a release paper, and the material of the release film is At least one of polypropylene, biaxially oriented polypropylene, and polyethylene terephthalate.

The low profile copper foil layer 100, the upper dielectric adhesive layer 200, the core layer 300 and the lower dielectric adhesive layer 400 have a laminate having a bonding strength of >0.7 kgf/cm and a water absorption of 0.01% to 1.5%.

The inventive examples were compared to prior art LCP panels for basic performance and the results are reported in Tables 1 and 2 below.

In Table 1, the low profile copper foil layer of each embodiment is a rolled copper foil layer of HAV2 product of Nippon Mining & Metal Co., Ltd.; the material of the upper dielectric adhesive layer comprises Teflon® MP 1200 (Dupont) and 30 % polyimine resin (T100, Shanghai Duokang Industrial Co., Ltd.); the core layer is made of polyimide film (20EN, Dupont); the material of the lower dielectric layer includes Teflon ® MP 1200, Dupont) and 30% polyimide resin (T100, Shanghai Dokang Industrial Co., Ltd.).

Note: The test method implementation of the performance indicators of Table 1 and Table 2 is based on the "Test Guidelines for Soft Board Assembly Requirements" (TPCA-F-002)

It can be seen from Table 1 and Table 2 that the low dielectric loss FRCC substrate with composite stack has excellent high-speed transmission, low thermal expansion coefficient, stable Dk/Df performance under high temperature and humidity environment, and ultra low Water absorption, good UV laser drilling capability, low resilience for high density assembly and excellent mechanical properties.

The above description is only an embodiment of the present invention, and thus does not limit the scope of the patent of the present invention. Any equivalent structure made by using the contents of the present specification and the drawings, or directly or indirectly applied to other related technical fields, is the same. It is included in the scope of patent protection of this creation.

Claims (8)

A composite flexible coated copper foil substrate comprises: a core layer having opposite upper and lower surfaces, and the material forming the core layer is polyimine; upper dielectric layer and lower dielectric a glue layer is formed on the upper surface and the lower surface of the core layer respectively; a low profile copper foil layer is formed on the upper dielectric adhesive layer, so that the upper dielectric adhesive layer is sandwiched between the core layer and the lower layer Between the contour copper foil layers, wherein the low profile copper foil layer has a surface roughness Rz value of 0.4 to 1.0 μm, and the low profile copper foil layer is a rolled copper foil layer or an electrolytic copper foil layer; and a release layer, Formed on the lower dielectric adhesive layer such that the lower dielectric adhesive layer is sandwiched between the core layer and the release layer. The composite flexible coated copper foil substrate according to claim 1, wherein the core layer has a thickness of 5 to 50 μm. The composite flexible coated copper foil substrate according to claim 1, wherein the upper dielectric adhesive layer has a thickness of 2 to 50 μm, and the lower dielectric adhesive layer has a thickness of 2 to 50 μm. The composite flexible coated copper foil substrate according to claim 1, wherein the low profile copper foil layer has a thickness of 1 to 35 μm. The composite flexible coated copper foil substrate according to claim 1, wherein the upper dielectric adhesive layer and the lower dielectric adhesive layer are thermosetting polyimine-based resin adhesive layers. The composite flexible coated copper foil substrate according to claim 1, wherein the Dk values of the upper dielectric layer and the lower dielectric layer are both It is from 2.0 to 3.0 (10 GHz) and the Df value is between 0.002 and 0.010 (10 GHz). The composite flexible coated copper foil substrate according to claim 1, wherein the release layer is a release film or a release paper. The composite flexible coated copper foil substrate according to claim 1, wherein the low profile copper foil layer, the upper dielectric adhesive layer, the core layer and the lower dielectric adhesive layer are laminated. The strength is >0.7 kgf/cm, and the water absorption is 0.01 to 1.5%.