TW201900409A - Resin composition for forming insulating glue layer and composite metal substrate structure including a first metal layer, a liquid crystal polymer layer, an insulating glue layer and a second metal layer - Google Patents

Abstract

A composite metal substrate structure includes a first metal layer, a liquid crystal polymer layer formed on the first metal layer, an insulating glue layer formed on the liquid crystal polymer layer, and a second metal layer formed on the insulating glue layer such that the liquid crystal polymer layer and the insulating glue layer are sandwiched between the first metal layer and the second metal layer, wherein the composite metal substrate structure has a thickness of 11 to 220 micrometers ([mu]m). This invention further provides a resin composition for forming an insulating glue layer.

Description

 Resin composition for forming an insulating layer and composite metal substrate structure  

The invention relates to a composite metal substrate structure, in particular to a composite metal substrate structure with high frequency and good weather resistance.

Printed circuit boards are an indispensable material in electronic products, and as the demand for consumer electronics grows, so does the demand for printed circuit boards. Due to the flexible and flexible three-dimensional wiring of flexible printed circuit boards (FPC), the development of technology-based electronic products emphasizes the advantages of lightness, shortness, flexibility, and high frequency. Widely used in computers and peripherals, communication products and consumer electronics.

In the high-frequency field, the wireless infrastructure needs to provide a sufficiently low differential to effectively improve energy efficiency. With the accelerated development of 5G communication, millimeter wave, and aerospace military, with the rise of emerging industries such as big data and Internet of Things and the popularity of mobile interconnection terminals and the rapid processing and transmission of information, it has become the focus of the communication industry.

In the field of communication, the future 5G network has higher speed bandwidth and denser 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.

However, FPC 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. The high-frequency substrates currently used in the industry are mainly liquid crystal polymer (LCP) plates and polytetrafluoroethylene (PTFE) fiber boards. However, they are also limited by the process technology, and have high requirements for manufacturing equipment and need to be in a higher temperature environment. (>280 °C) can be operated, which also causes uneven film thickness, and uneven film thickness will make the impedance control of the circuit board difficult, while other resin films do not have the above problems, but they are not electrically Good, the force is too weak or the mechanical strength is not good.

In order to meet the requirements of high frequency transmission, high speed, heat dissipation, heat conduction and low production cost, the design and application of various forms of mixed-pressure structure multilayer boards (such as composite substrates) have emerged.

A composite substrate having excellent workability, low cost, and low energy consumption is proposed in the Japanese Patent No. 201590948 U, the Taiwan Patent No. M377823, the Japanese Patent No. 2010-7418A, and the Japanese Patent No. 2011/0114371. In the Chinese Patent No. 202276545 U, the Chinese Patent No. 103096612 B, the Taiwan Patent No. M422159, and the Taiwan Patent No. M531056, a high frequency substrate is produced from a fluorine-based material.

In addition, since the general polyimine (PI) type and the thermosetting polyimine (TPI) type copper foil substrate have high hygroscopicity (about 1 to 2%), in the process of preparing the composite substrate, there will be The problem of bursting has seriously affected the yield. In addition, the preparation of high-frequency substrates with LCP or TPI requires high-temperature pressing (compression temperature between 280 and 330 ° C), especially when producing composite substrates with a thickness of 38 μm or more and better transmission performance. There are also some shortcomings such as low production efficiency and high production cost.

Therefore, it is still necessary to develop a composite metal substrate structure having low signal transmission loss, low repulsive force, and low hygroscopicity.

The present invention provides a composite metal substrate structure, comprising: a first metal layer; a liquid crystal polymer layer formed on the first metal layer; an insulating layer formed on the liquid crystal polymer layer; and the insulating layer formed on the insulating layer The second metal layer on the adhesive layer sandwiches the liquid crystal polymer layer and the insulating adhesive layer between the first and second metal layers, and the composite metal substrate has a thickness of 11 to 220 μm.

The present invention provides a resin composition for forming an insulating rubber layer, comprising: an insulating resin having a content of 40 to 90% based on the total weight of the resin composition; and a first fluorine resin; The content of the first fluorine-based resin is 2 to 10% based on the total weight of the resin composition; and the content of the second fluorine-based resin is 2 to 2 based on the total weight of the resin composition. 10%; a flame retardant having a content of the flame retardant of 2 to 15% based on the total weight of the resin composition; and an inorganic powder based on the total weight of the resin composition, the second fluorine resin The content is 2 to 15%.

In order to make the composite metal substrate structure of the present invention have good mechanical strength and physicochemical properties, the present invention provides a method for fabricating a composite metal substrate structure. The method comprises the steps of: forming a liquid crystal polymer layer on the first metal layer; forming an insulating glue layer on the liquid crystal polymer layer; and forming a second metal layer on the insulating rubber layer.

The resin composition of the present invention is obtained by mixing two kinds of fluorine-based resins in an insulating resin to provide an insulating material having a lower dielectric loss, and by adding an inorganic powder to the insulating resin to reduce moisture absorption of the insulating material. Sex.

Therefore, in the composite metal substrate structure of the present invention, the insulating adhesive layer and the liquid crystal polymer layer are simultaneously provided, so that the composite metal substrate structure can not only have low signal loss, but also a low film and an uncoated film. Resilience also maintains low hygroscopicity and high adhesion strength.

1, 2‧‧‧Composite metal substrate structure

10‧‧‧First metal layer

20‧‧‧Liquid polymer layer

20'‧‧‧Another liquid crystal polymer layer

30‧‧‧Insulating rubber layer

40‧‧‧Second metal layer

1 is a schematic cross-sectional view showing a composite metal substrate structure of the present invention; and FIG. 2 is a cross-sectional view showing a composite metal substrate structure according to another embodiment of the present invention.

The other embodiments of the present invention will be readily understood by those skilled in the art from this disclosure.

It is to be understood that the structure, the proportions, the size, and the like of the present invention are intended to be used in conjunction with the disclosure of the specification, and are not intended to limit the invention. The conditions are limited, so it is not technically meaningful. Any modification of the structure, change of the proportional relationship or adjustment of the size should remain in this book without affecting the effects and the objectives that can be achieved by the present invention. The technical content disclosed in the invention can be covered. In the meantime, the terms "a" and "an" are used in the specification for the purpose of description and are not intended to limit the scope of the invention. The following is also considered to be an area in which the invention can be implemented.

The composite metal substrate structure of the present invention is as shown in Fig. 1. The composite metal substrate structure 1 of the present invention comprises a first metal layer 10; a liquid crystal polymer layer 20 formed on the first metal layer 10; The insulating adhesive layer 30 on the liquid crystal polymer layer 20; and the second metal layer 40 formed on the insulating adhesive layer 30, the liquid crystal polymer layer 20 and the insulating adhesive layer 30 are sandwiched between the first metal layer 10 Between the second metal layer 40 and the second metal layer 40.

In the embodiment, the composite metal substrate structure 1 has a thickness of 11 to 220 μm.

In a specific embodiment, the first metal layer 10 and the second metal layer 40 are independently selected from the group consisting of a copper foil or an electrolytic copper foil having a thickness of 1 to 35 μm, and more preferably, the first metal layer 10 and the first The thickness of the two metal layers 40 is independently 6 to 18 μm. In the foregoing embodiment, the inner surface of the first metal layer 10 and the second metal layer 40 has a surface roughness (Rz) of 0.14 to 1.0 μm, and the outer surface of the first metal layer 10 and the second metal layer 40 The surface roughness (Rz) is 0.4 to 0.7 μm. In the foregoing embodiment, the inner surface of the first metal layer 10 and the second metal layer 40 has a surface roughness (Rz) of 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm or 1.0 μm. The surface roughness (Rz) of the outer surface is 0.4 μm, 0.5 μm, 0.6 μm or 0.7 μm.

In one embodiment, the liquid crystal polymer layer 20 has a thickness of 5 to 50 μm. In the foregoing embodiment, the liquid crystal polymer layer 20 has a water absorption ratio of 0.01 to 0.1%, and more preferably, the liquid crystal polymer layer 20 has a water absorption ratio of 0.01 to 0.04%.

In one embodiment, the thickness of the insulating layer 30 is 2 to 50 μm, and more preferably, the thickness of the insulating layer is 12.5 to 50 μm.

In one embodiment, the water absorption of the insulating layer 30 is 0.01 to 0.1%, and more preferably, the water absorption of the insulating layer 30 is 0.01 to 0.08.

In one embodiment, the overall water absorption of the composite metal substrate structure 1 of the present invention is 0.01 to 0.5%, and more preferably, the overall water absorption of the composite metal substrate structure is 0.01 to 0.1%.

In one embodiment, the insulating layer 30 has a dielectric constant of 2.0 to 3.0 (10 GHz). More preferably, the insulating layer 30 has a dielectric constant of 2.2 to 3.0.

In one embodiment, the dielectric layer 30 has a dielectric loss factor of 0.002 to 0.010 (10 GHz).

In one embodiment, the insulating layer 30 has an adhesion strength greater than 0.7 kgf/cm ² .

In one embodiment, the material forming the insulating layer 30 is selected from the group consisting of epoxy resin, acrylic resin, urethane resin, silicone rubber, polyparaxylene resin, and double horse. At least one of the group consisting of a quinone imine resin and a polyimine resin.

In one embodiment, the insulating layer 30 contains an inorganic powder, a first fluorine-based resin, a second fluorine-based resin, and a flame retardant. In the foregoing embodiment, the inorganic powder is cerium oxide, preferably sintered cerium oxide, and the first fluororesin may be polytetrafluoroethylene (PTFE), and the flame retardant is a phosphorus-based flame retardant.

In a specific embodiment, the material forming the insulating adhesive layer 30 comprises a fluorine-based resin different from polytetrafluoroethylene and a flame retardant, and the fluorine-based resin and the flame retardant are based on the total weight of the insulating rubber layer. The sum of the contents is 4 to 50%.

In one embodiment, the material forming the insulating layer comprises ceria and polytetrafluoroethylene, and the sum of the content of the ceria and the polytetrafluoroethylene is 4 based on the total weight of the insulating layer. Up to 25%.

As shown in FIG. 2, in another embodiment of the composite metal substrate structure 2 of the present invention, another liquid crystal polymer layer 20' is formed on the insulating adhesive layer 30 and the second metal layer 40. between.

In the present embodiment, the thickness of the liquid crystal polymer layer 20 and the other liquid crystal polymer layer 20' are each 1.25 to 50 μm.

The present invention provides a resin composition for forming an insulating rubber layer, comprising: an insulating resin having a content of 40 to 90% based on the total weight of the resin composition; and a first fluorine resin; The content of the first fluorine-based resin is 2 to 10% based on the total weight of the resin composition; and the second fluorine-based resin different from the first fluorine-based resin, based on the total weight of the resin composition, the first The content of the difluoro resin is 2 to 10%; the flame retardant is 2 to 15% based on the total weight of the resin composition; and the inorganic powder is the total of the resin composition The content of the second fluorine-based resin is from 2 to 15% by weight.

In one embodiment, the insulating resin is selected from the group consisting of an epoxy resin, an acrylic resin, a urethane resin, a ruthenium rubber resin, a polyparaxylene resin, and a bismaleimide resin. And at least one of the group consisting of polyamidiene-based resins.

In one embodiment, the first fluorine-based resin is polytetrafluoroethylene.

In a specific embodiment, the flame retardant is a phosphorus-based flame retardant, specifically, the phosphorus-based flame retardant is a phosphate, a phosphite, a phosphate, an organic phosphorus salt, and a phosphorus heterocycle. Compounds and polymers such as phosphorus (phosphonate).

In one embodiment, the inorganic powder system is cerium oxide. In order to make the composite metal substrate structure of the present invention have good mechanical strength and physicochemical properties, the present invention provides a method for fabricating a composite metal substrate structure. The method comprises the steps of: forming a liquid crystal polymer layer on the first metal layer; forming an insulating glue layer on the liquid crystal polymer layer; and forming a second metal layer on the insulating glue layer.

In a specific embodiment, the step of forming a liquid crystal polymer layer on the first metal layer comprises: coating a liquid crystal polymer on the first metal layer, and baking the solvent at a temperature of 60 to 100 ° C to remove the solvent. After baking at 300 ° C for 10 hours, it was yellowed to obtain the liquid crystal polymer layer.

In one embodiment, the step of forming an insulating layer comprises applying an insulating paste on the liquid crystal polymer layer and baking at 60 to 100 ° C to obtain the insulating layer.

In one embodiment, the step of forming a second metal layer on the insulating layer comprises laminating the second metal to the insulating layer. In the foregoing specific examples, the temperature of the press is from 50 to 130 °C.

 Embodiment 1 and 4 method for manufacturing composite metal substrate structure of the present invention  

The LCP varnish (Model VR400 produced by Sumitomo Chemical Co., Ltd.) was coated on the copper foil layer as shown in Table 1. The solvent was baked at 60 to 100 ° C and baked at 300 ° C for 10 hours to make it yellow. The liquid crystal polymer layer is obtained, and an insulating paste is applied on the liquid crystal polymer layer, and the composition of the insulating rubber is as shown in Table 2, wherein the fluorine resin is a 300 AS BK fluororesin of DuPont, and the phosphorus system is used. The flame retardant is made of Clariant's OP935 flame retardant and baked at 60 to 100 ° C to remove the solvent to obtain an insulating layer. The thickness of the insulating layer is as shown in Table 1. Copper foil layer.

 Embodiments 2, 3 and 5 of the method for manufacturing a composite metal substrate of the present invention  

The same processes as in Examples 1 and 4 were employed except that in Examples 1 and 4, after the formation of the insulating layer, LCP varnish (Sumitomo Chemical Co., Ltd. model VR400) was applied to the insulating layer. And baking at 60 to 100 ° C temperature to remove the solvent, baking at 300 ° C for 10 hours to yellowing to obtain another liquid crystal polymer layer, and the second copper foil layer is pressed against the other liquid crystal polymer On the floor.

The thickness of each layer of the composite metal substrate structure of Examples 1 to 5 is shown in Table 1.

 Comparative Examples 1 to 2 Conventional Polyimine Substrates  

The first electrodeposited copper foil and the second electrodeposited copper foil were press-bonded to a polyimide core layer (KANEKE Corporation; model FRS-142#SW) to obtain a composite film of Comparative Example 1 having a total thickness of 50 μm.

 Test case  

The composite film composite metal substrate structure prepared according to the foregoing examples and comparative examples was subjected to water absorption test, electrical characteristics (dielectric constant and dielectric loss factor) test, and subsequent strength, rebound of the film and uncoated film. Force test and solder resistance test, and the test results are recorded in Tables 3 and 4.

 Water absorption test:  

Before the normal temperature soaking water and the normal temperature soaking water 24, the water absorption rate was measured according to the water absorption test method of the soft board assembly test standard IPC-TM650 2.6.2, and the results are recorded in Table 3.

 Then the strength test:  

According to the adhesive strength test method of the soft board assembly test standard IPC-TM650 2.4.9, the subsequent strength was measured, and the results are recorded in Table 3.

 Rebound test:  

The rebound force of the film and the uncoated film was measured by a rebound tester (APLUS) according to the following test method, and the results are reported in Table 3. The test method was such that the substrates of Examples 1 to 4 and Comparative Examples 1 to 2 of the uncoated and uncoated films were cut into test pieces of a size of 10 mm × 30 mm, and the test pieces were attached to a rebound force tester, and the amount was measured.

 Dielectric constant and dielectric loss factor measurement:  

The measurements were made in accordance with the ASTM 2520 Waveguide Resonators test method and the results are reported in Table 4. Then use the following formula to calculate the high-speed transmission signal loss: high-speed transmission signal loss = conductor loss (Conductor loss) + dielectric loss (Dielectric loss)

Wherein Dk: Dielectric constant; Df: Dissipation factor; f: Frequency; and c: Light velocity.

 Solder resistance test (thermal stress test method):  

Using the thermal stress test method of IPC-TM-65022, the substrate material was evaluated under the high temperature tin furnace to understand the heat resistance of the material. The test method was as follows: The substrates of Examples 1 to 4 and Comparative Examples 1 to 2 were first pre-baked in an oven (121 to 149 ° C) for 0.5 to 1.0 hours. Each of the substrates was taken out and placed in a drying dish to room temperature, and then placed in a tin furnace (300 ° C) for 10 seconds. The appearance of each of the substrates was visually observed to change after immersion in the tin furnace. Evaluate as follows:

○: The appearance did not change at all.

×: The appearance of the explosion or peeling is recorded in Table 4 below.

Referring to the results of Tables 3 and 4, it can be seen that the composite metal substrate structures of Embodiments 1 to 5 of the present invention have lower high transmission loss signal loss and lower coating film than Comparative Examples 1 to 4. With the rebound of the uncoated film. Further, the composite metal substrate structures of Embodiments 1 to 5 of the present invention are not only superior in electrical characteristics to Comparative Examples 1 to 2 (a conventional PI substrate), but also have a lower water absorption rate, and are superior to Comparative Examples 3 and 4 (Study Knowing the solder resistance of the LCP substrate, the composite metal substrate structures of Embodiments 1 to 5 of the present invention can pass the higher temperature thermal stress test (Comparative Examples 3 and 4 did not pass the solder resistance test).

It can be seen that the composite metal substrate structure of the present invention is superior to the general PI substrate in water absorption rate and high-speed transmission performance, and is superior to the conventional LCP substrate even better than the conventional LCP substrate, and can solve the LCP or TPI substrate at the same time. The disadvantages of high price, strong rebound and poor workability.

The composite metal substrate structure of the invention has excellent high-speed transmission property, good solder resistance, stable electrical characteristics (dielectric constant and dielectric loss factor) in a high temperature and humidity environment, low water absorption rate and low rebound force, etc. Excellent mechanical properties for high density assembly and UV laser drilling processes.

The above-described embodiments are merely illustrative of the effects of the present invention, and are not intended to limit the present invention, and those skilled in the art can implement the above-described embodiments without departing from the spirit and scope of the present invention. Make modifications and changes. In addition, the number of elements in the above-described embodiments is merely illustrative and is not intended to limit the invention. Therefore, the scope of protection of the present invention should be as set forth in the appended claims.

Claims (19)

 A composite metal substrate structure includes: a first metal layer; a liquid crystal polymer layer formed on the first metal layer; an insulating glue layer formed on the liquid crystal polymer layer; and a second metal layer, Formed on the insulating adhesive layer, the liquid crystal polymer layer and the insulating adhesive layer are sandwiched between the first and second metal layers, and the composite metal substrate structure has a thickness of 11 to 220 μm.    The composite metal substrate structure according to claim 1, wherein the material forming the first metal layer and the second metal layer is independently selected from a rolled copper foil or an electrolytic copper foil.    The composite metal substrate structure according to claim 1, wherein the surface roughness (Rz) of the inner surface of the first metal layer and the second metal layer in the composite metal substrate structure is 0.4 to 1.0. Μm, and the surface roughness (Rz) of the outer side surfaces of the first metal layer and the second metal layer is 0.4 to 0.7 μm.    The composite metal substrate structure according to claim 1, wherein the liquid crystal polymer layer has a thickness of 5 to 50 μm.    The composite metal substrate structure according to claim 1, wherein the insulating rubber layer has a thickness of 2 to 50 μm.    The composite metal substrate structure according to claim 1, further comprising another liquid crystal polymer layer formed between the insulating rubber layer and the second metal layer, and the insulating rubber layer is sandwiched between Between the liquid crystal polymer layer and the other liquid crystal polymer layer.    The composite metal substrate structure of claim 4, wherein the liquid crystal polymer layer and the other liquid crystal polymer layer each have a thickness of 1.25 to 50 μm.   The composite metal substrate structure according to claim 1, wherein the insulating layer has a water absorption of 0.01 to 0.1%, and then the strength is greater than 0.7 kgf/cm ² , and the water absorption of the liquid crystal polymer layer is 0.01 to 0.1%, and the overall water absorption of the composite metal substrate structure is 0.01 to 0.5%.  The composite metal substrate structure according to claim 1, wherein the insulating layer has a dielectric constant of 2.0 to 3.0 (10 GHz).    The composite metal substrate structure according to claim 1, wherein the insulating layer has a dielectric loss factor of 0.002 to 0.010 (10 GHz).    The composite metal substrate structure according to claim 1, wherein the material for forming the insulating layer is selected from the group consisting of an epoxy resin, an acrylic resin, a urethane resin, a ruthenium rubber resin, and a poly At least one of a group consisting of a cycloxylene resin, a bismaleimide resin, and a polyamidene resin.    The composite metal substrate structure according to claim 1, wherein the material forming the insulating rubber layer comprises a fluorine resin and a flame retardant, and the fluorine resin and the total weight of the insulating rubber layer The sum of the contents of the flame retardant is 4 to 50%.    The composite metal substrate structure according to claim 12, wherein the flame retardant is a phosphorus-based flame retardant.    The composite metal substrate structure of claim 1, wherein the material forming the insulating layer comprises ceria and polytetrafluoroethylene, and the ceria is based on the total weight of the insulating layer. The sum of the content of polytetrafluoroethylene and the content of polytetrafluoroethylene is 4 to 25%.    A resin composition for forming an insulating rubber layer, comprising: an insulating resin, the insulating resin is contained in an amount of 40 to 90% by weight based on the total weight of the resin composition; and the first fluorine-based resin is a resin composition The total amount of the first fluorine-based resin is 2 to 10%; and the second fluorine-based resin is 2 to 10% by weight based on the total weight of the resin composition; a fuel additive having a content of the flame retardant of 2 to 15% based on the total weight of the resin composition; and an inorganic powder having a content of 2 to 15 based on the total weight of the resin composition %.    The resin composition according to claim 15, wherein the insulating resin is selected from the group consisting of an epoxy resin, an acrylic resin, an urethane resin, a ruthenium rubber resin, and a polyparaxylene resin. At least one of a group consisting of a bismaleimide resin and a polyamidene resin.    The resin composition according to claim 15, wherein the first fluorine-based resin is polytetrafluoroethylene.    The resin composition according to claim 15, wherein the flame retardant is a phosphorus-based flame retardant.    The resin composition according to claim 15, wherein the inorganic powder system is formed into cerium oxide.