TWM446478U - Copper clad laminate for printed circuit board - Google Patents

Description

Copper foil substrate for printed circuit boards

The present invention relates to a copper foil substrate, and more particularly to a copper foil substrate having an opaque insulating layer, an adhesive layer and a reinforcing film.

At present, the electronic system is oriented toward light and short, high heat resistance, versatility, high density, high reliability and low cost, so the selection of the substrate becomes an important factor. A good substrate must have high thermal conductivity, high dimensional stability, high opacity, high heat dissipation, high heat resistance, and low thermal expansion coefficient. Polyimine resin has been widely used in electronic materials because of its high thermal stability and excellent heat dissipation, mechanical strength and adhesion, for example, for a Flexible Printed Circuit (FPC).

At present, polyimine composite membranes have been widely used in electronic materials. However, the manufacturing process of the rubber-free single-sided copper foil substrate on the flexible printed circuit board is complicated, and the rubber-free single-sided copper foil substrate and the poly-Asian The surface of the amine composite membrane layer is susceptible to contamination and other factors, resulting in poor adhesion. In addition, the high temperature surface finish process (SMT) in the process often causes the explosion of the reinforcing plate. In addition, if the stiffness of the selected material is insufficient, the problem of production yield and dimensional stability may be encountered in the flexible printed circuit board process.

In addition, in order to avoid the easy designation of the circuit layer design of the flexible printed circuit board, it is plagiarized by the industry, thereby affecting the company's operation. Therefore, it is still necessary to develop a copper foil substrate with high dimensional stability, high stiffness and easy processing characteristics that meets the requirements of the FPC downstream client. In electronic products such as mobile phones, notebook computers, LCD screens, consumer electronics and electronic devices, and navigation screens for automotive electronic flexible printed circuit boards or medical carriers.

Accordingly, the present invention provides a copper foil substrate for a printed circuit board, comprising: a copper foil layer; a black polymer layer formed on the copper foil layer; and an adhesive layer formed on the black polymer layer to Laying the black polymer layer between the copper foil layer and the adhesive layer; and forming a black reinforcing film on the adhesive layer such that the adhesive layer is sandwiched between the black polymer layer and the black reinforcing film Wherein the sum of the thickness of the black polymer layer and the adhesive layer is between 8 and 50 microns.

The beneficial effect of the creation is that the copper foil substrate for the printed circuit board of the present invention is composed of a copper foil layer, a black polymer layer, an adhesive layer and a black reinforcing film, and is prepared by a simple process method, and can be made according to a customer. The end needs, and the thickness of the adhesive layer and the black polymer layer are adjusted as needed. In addition, the copper foil substrate used for the printed circuit board of the present invention also meets the requirements of high dimensional stability, high stiffness and easy processing, and is particularly suitable for related electronic products such as mobile phone antenna boards.

The embodiments of the present invention are described by way of specific examples, and those skilled in the art can readily understand the advantages and effects of the present invention from the disclosure of the present disclosure. This creation can also be implemented in a variety of different ways, that is, it can be modified and changed without departing from the scope of this creation.

It is to be understood that the structure, the proportions, the size and the like of the drawings are only used in conjunction with the disclosure of the specification for the understanding and reading of those skilled in the art, and are not intended to limit the implementation of the present invention. The qualifications are not technically meaningful, and should not fall within the scope of the technical content disclosed in this creation without affecting the effectiveness and possible accomplishment of this creation. In the meantime, the term "upper" as used in this specification is only for convenience of description. The reversed schematic mode is only used to present the general product status, and there is no limit.

In the present specification, the glass transition temperature (Tg) is related to the heat resistance of the adhesive layer. In the context of the present invention, the glass transition temperature is one of transition temperatures, especially the phase change temperature of a material, specifically, the temperature of the material is high or low with heating or cooling. At temperature, the phase changes to a rubbery or brittle glass state.

The gloss described in this creation refers to the degree of reflected light of the black polymer layer, the black adhesive layer, and the black reinforcing film. Gloss does not have a unit, and the larger the value, the stronger the intensity of the reflected light; conversely, the smaller the gloss value, the weaker the intensity of the reflected light.

Referring to FIG. 1, the copper foil substrate for a printed circuit board of the present invention comprises: a copper foil layer 10; a black polymer layer 11 formed on the copper foil layer 10; and an adhesive layer 12 formed on the black polymer. On the object layer 11 such that the black polymer layer 11 is interposed between the copper foil layer 10 and the adhesive layer 12; and the black reinforcing film 13 formed on the adhesive layer 12 to make the adhesive layer 12 is sandwiched between the black polymer layer 11 and the black reinforcing film 13, wherein the total thickness of the black polymer layer 11 and the adhesive layer 12 is between 8 and 50 microns.

In the present creation, the copper foil may be a rolled copper foil, an electrolytic copper foil, a high-temperature high-buckling copper foil or a carrier ultra-thin copper foil. Generally, the thickness of the copper foil layer is between 3 and 70 microns. In a specific example, the thickness of the copper foil layer is between 3 and 18 microns.

In order to prevent the soft printed circuit board manufactured by the copper foil substrate from having problems such as insufficient bonding force or quality problems such as blasting, as a further improvement of the present invention, the composition and thickness of the adhesive layer in the copper foil substrate can be adjusted as needed. .

The material of the adhesive layer of the present copper foil substrate generally includes an epoxy resin, an acrylic resin, a urethane resin, a ruthenium rubber resin, a polyparaxylene resin, and a bismaleimide. And a resin comprising at least one resin of the group consisting of a polyimide and a polyamide resin, and the adhesive layer may be a non-black adhesive layer or a black adhesive layer. Further, in order to improve the heat resistance of the present copper foil substrate, the adhesive layer to be used should have a glass transition temperature of more than 170 ° C, and more preferably greater than 220 ° C.

In one aspect, in order to make the copper foil substrate of the present invention applicable to a thinned flexible electronic product, the thickness of the black polymer layer in the copper foil substrate of the present invention is between 5 and 25 micrometers. And the thickness of the adhesive layer is between 3 and 25 microns. Therefore, it is possible to provide a copper foil substrate excellent in performance under the condition of effective cost control.

In the copper foil substrate of the present invention, a bright light type having a gloss of more than 70 can be used. a black polymer layer or a matte black polymer layer having a gloss of less than 30, and the black polymer layer used is not particularly limited, and a halogen-free black thermosetting polyimine material is preferably used, and more preferably used. A self-adhesive, halogen-free black thermosetting polyimide material.

In the copper foil substrate of the present invention, the black reinforcing film is a bright black reinforcing film having a gloss of more than 70 or a matt black reinforcing film having a gloss of less than 30. In one aspect, the black reinforced film is a black polyimide film, wherein the black polyimide film preferably has a thickness of 50 μm.

In another aspect of the black reinforcing film of the present invention, the black reinforcing film is a black polyimine composite film. Referring to FIG. 2, the copper foil substrate of the present invention comprises: a copper foil layer 20; a black polymer layer 21 formed on the copper foil layer 20; and an adhesive layer 22 formed on the black polymer layer 21 to The black polymer layer 21 is sandwiched between the copper foil layer 20 and the adhesive layer 22; and a black polyimide film composite film 23 formed on the adhesive layer 22 to sandwich the adhesive layer 22 Between the black polymer layer 21 and the black polyimine composite film 23, wherein the total thickness of the black polymer layer 21 and the adhesive layer 22 is between 8 and 50 microns.

In this illustrative example, the black polyimine composite film 23 includes: a plurality of black polyimide layers 231; and a plurality of adhesive layers 241 each formed between each of the black polyimide layers 231, and The total thickness Z of the black polyimine composite film 23 conforms to the relationship of the following formula (I): mX+nY=Z (I)

Wherein X is a single layer of black polyimine layer 231 having a thickness of 0.5 to 2 mil; m is a layer of black polyimine layer 231 of X; Indicates the number of layers of the adhesive layer 241 in the composite film; and Y indicates the thickness of each of the adhesive layers 241, and the Y is determined according to a specific Z value, wherein the Z value is between 50 and 200 microns. .

Preferably, the number of layers of the black polyimide layer and the thickness of the adhesive layer can be adjusted as needed to form a polyimide film having a specific thickness, which has the advantages of low cost and high flatness.

In the present invention, the black polymer layer and the black reinforcing film may be bonded using a black adhesive layer, where the black polymer layer, the black adhesive layer and the black reinforcing film system contain a black color developer, wherein the black color developer It is at least one kind or a mixture of one or more of black pigment, carbon powder, carbon nanotube, and black dye. Taking the black adhesive layer of the present invention as an example, the black developer accounts for 3 to 15% by weight of the solid content of the epoxy resin, preferably 4 to 8% by weight.

In this creation, the glossiness of the surface of the black polyimine composite film can be measured using a gloss meter (model BYK-4446 gloss meter micro-TRI-gloss) to determine a black matte side or a black matte side. The gloss measured by the glossiness is greater than 70, that is, it is judged to be a black matte surface; if the measured gloss is less than 30, it is judged as a black matte surface.

The copper foil substrate of the present invention can be completed by the following process steps. The process steps are as follows: First, a copper foil is provided, and polyacrylic acid is coated on any surface of the copper foil, and dried to form a poly After the quinone imine layer, the polyimine layer is tightly bonded to the copper foil to obtain a single-sided copper foil substrate.

Next, an adhesive layer is formed on the one-sided copper using a coating method or a transfer method. The surface of the polyimide substrate of the foil substrate is placed in a semi-polymerized B-stage state.

Then, a single layer of black polyimide film or a black polyimide film is applied, and the black polyimide film or the black polyimide film is attached to the adhesive layer and pressed together. The black polyimide film or the black polyimide film is tightly bonded to obtain a copper foil substrate.

Finally, the obtained copper foil substrate is baked to complete the finished copper foil substrate.

The copper foil substrate of the present invention is prepared by a simple process, and the thickness of the black polyimide layer and the adhesive layer can be adjusted as needed to meet the needs of customers at the downstream end of the FPC, and by adjusting the composition and thickness of the adhesive layer. The adhesive layer can have a high glass transition temperature and excellent heat resistance. In addition, the copper foil substrate of the present invention also has high stiffness, high dimensional stability and easy processing characteristics, and can be applied to printed circuit boards or electronic products.

Example 1:

Using a 3 micron carrier ultra-thin copper foil, and coating a 5 micron black polyaminic acid on the surface of the ultra-thin copper foil, and drying to form a black polyimine layer, the polyimine layer is formed. It is tightly bonded to the copper foil to obtain a single-sided copper foil substrate.

Next, a 5 μm adhesive layer was formed on the surface of the black polyimide layer of the single-sided copper foil substrate by a coating method or a transfer method, and the adhesive layer was placed in a semi-polymerized B-stage state. Then, a black polyimine composite film composed of a single layer of 2 mil black polyimide layer is attached to the adhesive layer, and is pressed to make the black polyimine composite film tightly adhered. Then, a copper foil substrate was obtained. Finally, the obtained copper foil substrate is baked to complete the finished copper foil substrate.

Example 2:

The same process as in Example 1 was carried out except that a black polyimine composite film composed of a 12 μm copper foil (1/3 Oz Copper) and a single layer of 8 mil black polyimide layer was used to prepare a copper foil substrate. .

Example 3:

The same process as in Example 1 was carried out except that an 18 μm copper foil (1/2 Oz Copper), a 25 μm black polyimide layer and a 25 μm adhesive layer were used to prepare a copper foil substrate.

Example 4:

In addition to the use of 18 micron copper foil (1/2 Oz Copper), 25 micron black polyimide layer, 25 micron adhesive layer and a single layer of 9 mil black polyimine layer Except for the composite film, the same process as in Example 1 was carried out to prepare a copper foil substrate.

Copper foil substrates were prepared using the above-described method according to the data in Tables 1 to 3 below for the following test examples.

Test Example 1: Rebound Force Test

The copper foil substrate of the present invention was used as an example, and the copper foil layer of the copper foil substrate of the present invention was etched away as a comparative example.

Test conditions for the rebound force test: The test piece was cut into 10 mm × 30 mm test pieces, and the test R angle was set to 2.35 mm, and each test piece was measured 5 times. The average value was calculated and recorded in Table 1.

It can be seen from the results shown in Table 1 that the rebound strength of the copper foil substrate of the present invention is superior to that of the comparative example under the same thickness condition, and the thicker the thickness of the polyimide film and the polyimide film, the more the rebound force is. Big, the better the stiffness. Therefore, the copper foil substrate of the present invention has high resilience and high stiffness.

Test Example 2: Dimensional stability test

The copper foil substrate of the present invention was taken as an example, and a general copper foil substrate was used as a comparative example.

Test conditions for dimensional stability: The copper foil substrate was cut into test pieces of 25 mm × 28 mm, and four holes were punched in the upper four corners. Method B measures the change in the size of the TD/MD after the copper foil layer of the copper foil substrate is removed by etching. The method C measures the TD/MD after baking at 150 degrees for 30 minutes. To the change in size, the test piece was measured 3 times, and the average value was calculated and recorded in Table 2.

It can be seen from the results shown in Table 2 that the copper foil substrate of the present invention has excellent dimensional stability, and the dimensional expansion and contraction values after etching and baking are all within -0.1%. In addition, under the same thickness conditions, the dimensional stability of the present invention is superior to that of the comparative example, and the thicker the polyimine layer and the polyimide polyimide composite film, the better the dimensional stability.

Test Example 3: Explosion test of copper foil substrate

Test conditions for the blasting board: The copper foil substrate was cut into 25 mm × 28 mm test pieces, placed in a constant temperature and humidity machine for 85 ° C / 85% RH test; for 96 hours; then taken out and placed in a 300 ° C tin furnace Test if it will explode occur. Each set of test pieces was measured 3 times, and the average value was calculated and recorded in Table 3.

From the results shown in Table 3, the copper foil substrate of the present invention was tested at 85 ° C / 85% RH, and after 96 hours, the test piece was taken out and immersed in a 288 ° C tin furnace test, and the test piece was taken out to observe that no blast occurred. It has excellent solder resistance.

The above description and examples are merely illustrative of the principles and functions of the present invention and are not intended to limit the present invention. The scope of protection of this creation shall be as set forth in the scope of the patent application described later.

10, 20‧‧‧ copper foil layer

11, 21‧‧‧ black polymer layer

12, 22‧‧‧ adhesive layer

13‧‧‧Black reinforced film

23‧‧‧Black Polyimine Composite Film

231‧‧‧Black Polyimine Layer

241‧‧‧ adhesive layer

Thickness of X‧‧‧ black polyimine layer

Y‧‧‧ thickness of the adhesive layer

Total thickness of Z‧‧‧ black polyimine composite film

Figure 1 is a schematic cross-sectional view showing the copper foil substrate of the present invention;

Figure 2 is a schematic cross-sectional view showing another copper foil substrate.

10‧‧‧copper layer

11‧‧‧Black polymer layer

12‧‧‧Adhesive layer

13‧‧‧Black reinforced film

Claims (16)

A copper foil substrate for a printed circuit board, comprising: a copper foil layer; a black polymer layer formed on the copper foil layer; an adhesive layer formed on the black polymer layer to make the black polymer layer Sandwiched between the copper foil layer and the adhesive layer; and a black reinforcing film formed on the adhesive layer such that the adhesive layer is sandwiched between the black polymer layer and the black reinforcing film, wherein the black polymerization The sum of the thickness of the layer and the adhesive layer is between 8 and 50 microns. The copper foil substrate for a printed circuit board according to claim 1, wherein the copper foil layer has a thickness of between 3 and 70 micrometers. The copper foil substrate for a printed circuit board according to claim 1, wherein the black polymer layer has a thickness of between 5 and 25 micrometers. The copper foil substrate for a printed circuit board according to claim 1, wherein the adhesive layer has a thickness of between 3 and 25 micrometers. The copper foil substrate for a printed circuit board according to claim 1, wherein the black reinforcing film is a black polyimide film or a black polyimide film. The copper foil substrate for a printed circuit board according to claim 5, wherein the black polyimine composite film comprises: a plurality of black polyimine layers; and a plurality of adhesive layers each formed in each The black polyimine layer And the total thickness Z of the black polyimine composite film conforms to the relationship of the following formula (I): mX+nY=Z (I) wherein X represents a single layer of black polythene having a thickness of 0.5 to 2 mil. An imine layer; m represents the number of layers of the black polyimine layer of X; n represents the number of layers of the adhesive layer in the composite film; and Y represents the thickness of each of the adhesive layers, and the Y system is specific to The Z value is between 50 and 200 microns. The copper foil substrate for a printed circuit board according to the first aspect of the invention, wherein the black polymer layer is a bright black polymer layer having a gloss of more than 70 or a matt black polymer having a gloss of less than 30. Floor. The copper foil substrate for a printed circuit board according to claim 1, wherein the black polymer layer is a black polyimide layer. The copper foil substrate for a printed circuit board according to the first aspect of the invention, wherein the material of the adhesive layer comprises an epoxy resin, an acrylic resin, a urethane resin, a ruthenium rubber system. At least one resin of a group consisting of a resin, a polyparaxylene resin, a bismaleimide resin, a polyimine resin, and a polyamide-methyleneamine resin. The copper foil substrate for a printed circuit board according to the first aspect of the invention, wherein the black reinforced film is a bright black reinforced film having a gloss of more than 70 or a matt black reinforced film having a gloss of less than 30. Copper foil for printed circuit boards as described in claim 1 The substrate, wherein the copper foil is a rolled copper foil, an electrolytic copper foil, a high-temperature high-buckling copper foil or a carrier ultra-thin copper foil. The copper foil substrate for a printed circuit board according to claim 1, wherein the adhesive layer is a black adhesive layer. The copper foil substrate for a printed circuit board according to claim 12, wherein the black adhesive layer is a bright black adhesive layer having a gloss of more than 70 or a matte black adhesive layer having a gloss of less than 30. The copper foil substrate for a printed circuit board according to the first aspect of the invention, wherein the black polymer layer and the black reinforcing film comprise a black developer. The copper foil substrate for a printed circuit board according to claim 12, wherein the black adhesive layer contains a black developer. The copper foil substrate for a printed circuit board according to claim 14 or 15, wherein the black color developer comprises at least one of a black pigment, a carbon powder, a carbon nanotube, and a black dye.