TWI640424B - Nano metal substrate for FPC and COF materials - Google Patents

Abstract

A nano metal substrate for FPC and COF materials, comprising a low thermal expansion coefficient polyimine layer, a rough polyimine layer formed on the low thermal expansion coefficient polyimine layer, and formed on a coarse polycondensation layer An ultra-thin nano metal layer on the imide layer, wherein the rough polyimine layer is interposed between the low thermal expansion coefficient polyimide layer and the ultra-thin nano metal layer. The nano metal substrate of the invention has excellent ion migration resistance, dimensional stability, chemical resistance, heat resistance and high temperature resistance and adhesion; suitable for laser processing blind holes and micropores, and is not easy to generate pinholes, suitable for Thin line etching, not easy to side erosion, to meet the needs of the development of thin-film substrate.

Description

 Nano metal substrate for FPC and COF materials  

The present invention relates to the field of electronic substrate technology, and more particularly to a nano metal substrate for ultrafine line FPC and COF materials.

Flexible Printed Circuit (FPC), commonly known as "soft board", is light, thin, short, and small. It is widely used in small electronic products such as mobile phones, digital cameras, and digital cameras. Chip On Film (COF) technology is a technology that combines a chip with a flexible circuit board circuit using a flexible circuit board as a package wafer carrier. As electronic products tend to be miniaturized, FPC or COF flexible circuit boards are required to be more powerful in function and tend to be high-frequency, high-density and thin-line.

The flexible copper clad laminate is a substrate material processed by FPC or COF, and the high density and thin line properties of the flexible copper clad laminate largely depend on the processing process of the thin copper foil portion.

At present, the substrate manufacturer mainly uses two types of manufacturing methods for the processing of the thin copper foil metal layer portion, one is a sputtering method or a copper plating method, and the other is a carrier copper foil method.

Sputtering or copper plating method, using a polyimide film (PI) film as a substrate, sputtering a chromium-containing alloy as an interposer on the PI film, and then sputtering a copper metal as a seed layer, and then electroplating copper to make copper The layer is thickened. However, in general, the surface roughness of the PI film is 10 to 20 nm, and the force is not good. It is necessary to surface-treat the PI film with plasma or short-wavelength ultraviolet rays, but the treated PI film requires high heat treatment for subsequent heat treatment, otherwise the force is deteriorated and peeled off. In addition, since the surface of the PI film has a certain roughness, pinholes are easily generated on the surface of the thin copper foil metal layer; and the thin copper foil metal layer produced by the method often causes incomplete etching in the COF or FPC etching process. Residual traces of chromium metal at the root of the line can cause ion migration problems and affect the quality of fine-lined COF or FPC.

In the carrier copper foil method, although the carrier layer can protect the copper foil from being damaged or scratched, there is a problem that it is difficult to peel off, which causes difficulty in processing, and stress residual during peeling tends to cause deformation and dimensional change of the copper foil. Further, the ultra-thin copper foil is expensive and difficult to obtain, and it is difficult to process the ultra-thin copper foil, so the thickness of the conventional copper foil is hard to be less than 6 μm.

The invention provides a nano metal substrate for ultra-fine line FPC and COF materials, which has excellent ion migration resistance, dimensional stability, chemical resistance, heat resistance and high temperature resistance and adhesion; suitable for laser processing blindness Hole/micro hole, and it is not easy to produce pinhole, suitable for fine line etching and not easy to side etching. In addition, the present invention adopts a nano copper design to meet the needs of the thin line development of the substrate.

In order to solve the above technical problems, the present invention provides a nano metal substrate for FPC and COF materials, comprising: a low thermal expansion coefficient polyimine layer having a thickness of 12.5 to 100 μm, having a first surface and a second surface opposite to each other And a coefficient of thermal expansion of 4 to 19 ppm/° C.; a roughened polyimine layer having a thickness of 2 to 5 μm formed on the first surface of the low thermal expansion coefficient polyimide layer; and a thickness of 90 to 800 nm The ultra-thin nano metal layer is formed on the rough polyimine layer, and the rough polyimine layer is located between the low thermal expansion coefficient polyimide layer and the ultra-thin nano metal layer. And the surface of the rough polyimine layer in contact with the ultra-thin nano metal layer is a rough surface having a roughness (Rz) of between 50 and 800 nm.

The beneficial effects of the nano metal substrate of the present invention for FPC and COF materials have at least the following points:

1. The multi-layer structure composed of the low thermal expansion coefficient polyimine layer and the rough polyimine layer of the invention can reduce the CTE (Coefficient of Thermal Expansion) value of the nano metal substrate, so that the nano metal The size of the substrate is smaller and smaller, and it has excellent dimensional stability and is suitable for applications in ultra-fine lines.

2. Since the roughened polyimine (PI) layer of the present invention has a surface roughness of between 50 and 800 nm, which is a roughened PI resin, can increase the adhesion to the metal layer, and the surface thereof After roughening treatment, it contains inorganic powder or flame retardant compound, and can be treated by surface corona and plasma treatment to increase surface energy and increase between coarsened polyimide layer and ultra-thin nano metal layer. The force, inorganic powder or flame retardant compound can also increase the hardness and flame retardancy of the surface.

3. When the ultra-thin nano metal layer of the invention comprises a multilayer alloy metal layer composed of a copper foil layer and other metal layers, the alloy layer is designed to improve the ion mobility resistance of the nano metal substrate and improve the fine line of the FPC or COF material. Quality and insulation properties.

4. The protective layer of the present invention may be provided with a carrier layer or a dry film layer, and the carrier film or the dry film are suitable for the semi-additive process, and the semi-additive method is more suitable for the thin and high-density thin line requirements of the FPC or COF material. And both the carrier film and the dry film can protect the ultra-thin nano metal layer from damage, padding and oxidation before the FPC or COF semi-addition process.

When the protective layer is selected from the carrier layer, the carrier layer is composed of a PET layer and a low adhesion layer, and the carrier layer is applied to the surface of the ultra-thin nano metal layer through a low adhesion layer, and the temperature resistance of the PET is 180 to 220 ° C, and the heat resistance and high temperature are high. Good adhesion; the release force of the low adhesion layer is only 1 to 5g/cm, so the carrier layer is easily peeled off, and it is not easy to cause the nano metal substrate to adhere to the carrier film after peeling, and the residual stress is small when peeling off. The deformation of the ultra-thin nano metal layer does not affect the dimensional stability of the substrate, which is beneficial to the use of downstream processing and improvement of yield.

When the protective layer is a dry film layer, the dry film layer comprises a photosensitive resin layer and a light transmitting layer, one side of the photosensitive resin layer covers the light transmitting layer and the other surface is attached to the surface of the ultra-thin nano metal layer, and is exposed to ultraviolet light. A part of the resin in the resin layer undergoes a cross-linking curing reaction to form a stable substance attached to the surface, and then develops and removes the film, thereby obtaining a desired line. Therefore, the use of dry film imaging has high reliability, and the downstream processing process can be reduced. Directly used for exposure development line etching, facilitating mechanization and automation.

5. When the low adhesion layer is made of high temperature resistant adhesive layer or acrylic adhesive layer, the adhesion is excellent, and the interface between the ultra-thin nano metal layer and the ultra-thin nano metal layer will not be delaminated/separated under high temperature and high humidity environment.

6. The nano metal substrate of the invention does not curl, has excellent dimensional stability, is suitable for laser processing, is suitable for microporous/blind holes and any hole shape requirements; and is used for multiple sputtering or multi-layer plating alloy, plating layer The copper is evenly distributed, and it is not easy to produce pinholes. It is suitable for fine line etching and is not easy to be edge-etched.

7. The ultrathin nano metal layer of the present invention preferably has a thickness of 90 to 200 nm, a line width/line distance of 15/15 μm, or even a 10/10 μm or lower line requirement, and the nano copper is designed to satisfy FPC or COF. The thinning requirements of the substrate.

100‧‧‧Low thermal expansion coefficient polyimine layer

100a‧‧‧ first surface

100b‧‧‧ second surface

200‧‧‧ coarse polyimine layer

300‧‧‧Ultra-thin nano metal layer

301‧‧‧copper layer

301a‧‧‧First copper foil surface

301b‧‧‧Second copper foil surface

302‧‧‧First metal sublayer

303‧‧‧Second metal sublayer

400‧‧‧Protective layer

401‧‧‧PET layer

402‧‧‧Low adhesive layer

403‧‧‧Photosensitive resin layer

404‧‧‧Transparent layer

1 is a schematic structural view of a single-sided nano metal substrate according to a first embodiment of the present invention; FIG. 2 is a schematic structural view of a double-sided nano metal substrate according to a second embodiment of the present invention; FIG. 4 is a schematic view showing the structure of the dry film layer of the present invention; FIG. 5 is a first schematic view showing six structures of the ultrathin nano metal layer of the present invention; and FIG. 6 is an ultrathin of the present invention. The second schematic of the six structures of the nano metal layer; the seventh figure is the third schematic of the six structures of the ultrathin nano metal layer of the present invention; and the eighth figure is the ultrathin nano metal layer of the present invention. The fourth schematic of the six structures; the ninth is a fifth of the six structures of the ultrathin nano metal layer of the present invention; and the tenth is the six structures of the ultrathin nano metal layer of the present invention. The sixth schematic diagram; and the 11th diagram illustrate the test method for dimensional stability.

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 "upper", "first", "second" and "one" are used in the description, and are not intended to limit the scope of the invention. Changes or adjustments in the relative relationship are considered to be within the scope of the present invention.

First embodiment

1 is a view showing a nano metal substrate according to a first embodiment of the present invention, comprising a low thermal expansion coefficient polyimine layer 100 having a thickness of 12.5 to 100 μm, having a first surface 100a and a second surface 100b opposite to each other, And a coefficient of thermal expansion of 4 to 19 ppm/° C.; a roughened polyimine layer 200 having a thickness of 2 to 5 μm formed on the first surface 100a of the low thermal expansion coefficient polyimide layer 100; and a thickness of 90 An ultra-thin nano metal layer 300 of 800 nm is formed on the rough polyimine layer 200 such that the rough polyimine layer 200 is located in the low thermal expansion coefficient polyimine layer 100 and ultrathin The surface of the rough polyimine layer 200 between the metal metal layers 300 and in contact with the ultra-thin nano metal layer 300 is a rough surface having a roughness of between 50 and 800 nm.

In addition, the nano metal substrate comprises a protective layer 400 having a thickness of 6 to 60 μm formed on the ultra-thin nano metal layer 300, and the ultra-thin nano metal layer 300 is located on the protective layer 400 and coarsened. Between the quinone imine layers 200. Further, another protective layer 400 is formed on the second surface 100b of the low thermal expansion coefficient polyimine layer 100.

Second embodiment

Referring to Fig. 2, there is shown a nano metal substrate according to a second embodiment of the present invention. The nano metal substrate further comprises another rough polyimine layer 200, another ultra-thin nano metal layer 300 and another protective layer 400, which are sequentially formed on the low thermal expansion coefficient polyimine layer 100. Above the second surface 100b.

In a preferred embodiment, the low thermal expansion coefficient polyimine layer 100 has a thickness of 12.5 to 50 μm, the ultra-thin nano metal layer 300 has a thickness of 90 to 200 nm, and the protective layer 400 has a thickness of 28 to 60 μm. The low thermal expansion coefficient polyimine layer 100 has a coefficient of thermal expansion of 4 to 11 ppm/° C. and the rough surface has a surface roughness of 80 to 400 nm.

The color of the low thermal expansion coefficient polyimine layer 100 and the rough polyimine layer 200 can be obtained by adding a pigment to the layer to obtain various colors such as black, yellow, white or transparent, but is not limited thereto. In one embodiment, the low thermal expansion coefficient polyimine layer 100 and the rough polyimine layer 200 of the present invention are both black, and the adhesion of the rough polyimine layer to the ultra-thin nano metal layer is used. More than 0.8kgf/cm.

The structure constituting the rough surface of the rough polyimine layer 200 may be subjected to surface corona or plasma treatment, or may be on the rough polyimine layer 200 (contact with the ultra-thin nano metal layer 300). The surface is formed with a powder coarsening sublayer composed of an inorganic powder containing at least one of the group consisting of cerium oxide, titanium oxide, aluminum oxide, aluminum hydroxide and calcium carbonate. A material layer or a material layer composed of at least one flame retardant compound powder of a halogen, a phosphorus system, a nitrogen system, and a boron system.

The ultra-thin nano metal layer 300 is a copper foil layer or a multilayer alloy metal layer composed of at least two metal layers, one of the at least two metal layers is a copper foil layer, and the other of the at least two metal layers Is selected from the group consisting of a silver layer, a nickel layer, a chromium layer, a palladium layer, an aluminum layer, a titanium layer, a copper layer, a molybdenum layer, an indium layer, a platinum layer or a gold layer, wherein the copper foil layer has a thickness of 90 to 150 nm, The other of the at least two metal layers has a thickness of 5 to 15 nm.

Referring to Figures 3 and 4, there is shown a schematic view of the structure of the carrier layer of the present invention.

As shown in FIG. 3, the protective layer 400 is a carrier layer composed of a PET layer 401 and a low adhesion layer 402 formed on the surface of the PET layer 401. The carrier layer is pasted by the low adhesion layer 402. The surface of the ultra-thin nano metal layer 300 (not shown), wherein the PET layer 401 has a thickness of 23 to 50 μm, the low adhesion layer 402 has a thickness of 5 to 10 μm, and the low adhesion layer 402 has a release force of 1 Up to 5g/cm.

When the low adhesion layer is made of a high temperature resistant adhesive layer or an acrylic adhesive layer, the adhesion is excellent, and the interface with the ultrathin nano metal layer 300 does not delaminate/separate under high temperature and high humidity environment.

As shown in FIG. 4, the protective layer 400 is a dry film layer including a photosensitive resin layer 403 and a light transmissive layer 404. One surface of the photosensitive resin layer 403 covers the light transmissive layer 404 and the other surface is attached to The surface of the ultra-thin nano metal layer 300.

Referring to Figures 5 through 10, the six structures of the ultra-thin nano metal layer 300 are illustrated.

As shown in Fig. 5, the ultra-thin nano metal layer 300 is composed of a single-layer copper foil layer 301 having a thickness of 0.1 to 0.2 μm.

6 to 10 illustrate that the ultra-thin nano metal layer 300 is a multilayer alloy metal layer composed of at least two metal layers, one of the at least two metal layers being a copper foil layer, and the at least two metal layers The other one is selected from the group consisting of a silver layer, a nickel layer, a chromium layer, a palladium layer, an aluminum layer, a titanium layer, a copper layer, a molybdenum layer, an indium layer, a platinum layer or a gold layer, wherein the copper foil layer has a thickness of 90 to At 150 nm, the other of the at least two metal layers has a thickness of 5 to 15 nm.

As shown in FIG. 6, the ultra-thin nano metal layer 300 is composed of a two-layer structure, that is, a copper foil layer 301 and a first metal sub-layer 302 formed on either side of the copper foil layer, and the material thereof is nickel. The copper foil layer 301 has a thickness of 90 to 150 nm, and the first metal sublayer 302 has a thickness of 5 to 15 nm.

As shown in FIG. 7, the ultra-thin nano metal layer 300 is a two-layer structure, and is composed of a copper foil layer 301 and a first metal sub-layer 302 formed of any one of the copper foil layers and made of silver. The layer 301 has a thickness of 90 to 150 nm, and the first metal sub-layer 302 has a thickness of 5 to 15 nm.

8 to 10 further illustrate that the ultra-thin nano metal layer 300 includes: a copper foil layer 301 having a first copper foil surface 301a and a second copper foil surface 301b; and a first metal sub-layer 302 Formed on the first copper foil surface 301a of the copper foil layer 301, and the material of the first metal sub-layer 302 is made of nickel; and the second metal sub-layer 303 is formed by the second copper of the copper foil layer 301. The foil surface 301b is disposed between the first metal sub-layer 302 and the second metal sub-layer 303, and the second metal sub-layer 303 is made of nickel, silver or copper.

As shown in FIG. 8, the material of the first metal sub-layer 302 is made of nickel, and the material of the second metal sub-layer 303 is silver. The thickness of the copper foil layer 301 is 90 to 150 nm, and the first metal sub-layer The thickness of the material of 302 and the second metal sub-layer 303 is each 5 to 15 nm.

As shown in FIG. 9, the material of the first metal sub-layer 302 is made of nickel, and the material of the second metal sub-layer 303 is also nickel. The thickness of the copper foil layer 301 is 90 to 150 nm. The thickness of the material of the layer 302 and the second metal sub-layer 303 is each 5 to 15 nm.

As shown in FIG. 10, the material of the first metal sub-layer 302 is made of nickel, the second metal sub-layer 303 is made of copper, and the copper foil layer 301 has a thickness of 90 to 150 nm. The first metal sub-layer The thickness of the material of 302 and the second metal sub-layer 303 is each 5 to 15 nm.

The method for producing a nano metal substrate for FPC and COF materials, wherein the preparation method is one of the following methods:

When the nano metal substrate is in the form of a single panel, a low thermal expansion coefficient polyimine layer is first provided, and the roughened polyimine is subjected to surface roughening treatment on one side of the low thermal expansion coefficient polyimine layer. a layer, which is then sputtered or plated to form an ultra-thin nano metal layer on the other side of the roughened polyimide layer, followed by a surface of the ultra-thin nano metal layer and a layer of low thermal expansion coefficient polyimine layer A protective layer is attached to one side, that is, the finished product is obtained.

When the nano metal substrate is in the form of a double panel, a low thermal expansion coefficient polyimine layer is first provided, and the roughened polyimine is subjected to surface roughening treatment on both sides of the low thermal expansion coefficient polyimine layer. a layer, and then forming an ultra-thin nano metal layer on the other side of the two layers of the roughened polyimide layer by sputtering or electroplating, and then respectively applying a protective layer on the surface of the two layers of the ultra-thin nano metal layer. That is, the finished product.

The dimensional stability properties of the nanometal substrates prepared in Examples 1 to 5 were tested in the following manner and compared with the existing nano metal substrates (Comparative Examples) (Sumitomo, S'perflex), and recorded as follows: The dimensional stability test method is carried out according to the 11th and following steps: 1. After the substrate is cut as shown in Figure 11, the four holes are punched around the punch by A, B, C, D; Calculate the distance (I) from A to B, C to D, A to C, B to the center of the D hole by a linear scale (GC92841) and record it. 3. Completely etch the copper of the substrate. After washing with water for 1 minute, wipe dry (23 ± 2 ° C; 50 ± 5% RH) and let stand for 24 hours; 4. Measure A to B, C to D, A to C with a quadruple coordinate meter, respectively. The distance from the center of B to D hole (F1) is recorded, and the dimensional stability data of MD and TD are calculated by Formula 1, which is the result of Method B. 5. The above substrate is baked at 150±2 °C for 30±2. Minutes, take it out and put it into a dry box (23±2°C, 50±5%RH) and let it stand for 24 hours. 6. Then measure A to B, C to D, A to C, B to D by the quadratic coordinate meter. The distance from the center of the hole (F2) and Record, the calculation formula to calculate the MD 1, the dimensional stability data TD, which, and to sum Results Method B Method C of the MD calculated, the change rate of the TD Method C as a result.

Note: AB: distance from A to B

CD: distance from C to D

AC: distance from A to C

BD: distance from B to D

MD: the amount of change in the mechanical direction

TD: The amount of change in product direction

I: initial state measurement

F(F1, F2): final state measurement

As can be seen from Table 1, the nano metal substrate of the present invention has a small size expansion ratio and good dimensional stability, and is suitable for use in ultrafine lines. The above is only the embodiment of the present invention, and thus does not limit the scope of the patent of the present invention. Any equivalent structural transformation made by using the specification and the drawings of the present invention, or directly or indirectly applied to other related technical fields, is the same. The scope of the invention is included in the scope of the patent protection of the present invention.

Claims (15)

A nano metal substrate for a flexible printed circuit board (FPC) and a flip chip package (COF) material, comprising: a low thermal expansion coefficient polyimine layer having a thickness of 12.5 to 100 μm, having a first surface opposite to And a second surface having a coefficient of thermal expansion of 4 to 19 ppm/° C.; a roughened polyimine layer having a thickness of 2 to 5 μm formed on the first surface of the low thermal expansion coefficient polyimide layer; and a thickness An ultrathin nano metal layer of 90 to 800 nm is formed on the rough polyimine layer such that the rough polythene layer is located in the low thermal expansion coefficient polyimide layer and ultrathin nano metal The surface of the roughened polyimine layer between the layers and in contact with the ultra-thin nanometal layer is a rough surface having a roughness (Rz) of between 50 and 800 nm. The nano metal substrate for FPC and COF materials according to claim 1 is further comprising a protective layer having a thickness of 6 to 60 μm formed on the ultrathin nano metal layer to make the ultrathin A metal layer of metal is positioned between the protective layer and the roughened polyimide layer. The nano metal substrate for FPC and COF materials according to claim 1, wherein the ultra-thin nano metal layer is formed by sputtering or electroplating. The nano metal substrate for FPC and COF materials according to claim 1 of the patent application includes another rough polyimine layer, another ultra-thin nano metal layer and another protective layer. The sequence is formed on the second surface of the low thermal expansion coefficient polyimide layer. The nano metal substrate for FPC and COF materials according to claim 1, wherein the low thermal expansion coefficient polyimide layer has a thickness of 12.5 to 50 μm. The nano metal substrate for FPC and COF materials according to claim 1, wherein the ultrathin nano metal layer has a thickness of 90 to 200 nm. The nano metal substrate for FPC and COF materials according to claim 2, wherein the protective layer has a thickness of 28 to 60 μm. The nano metal substrate for FPC and COF materials according to claim 1, wherein the low thermal expansion coefficient polyimine layer has a thermal expansion coefficient of 4 to 11 ppm/° C. The nano metal substrate for FPC and COF materials according to claim 1, wherein the rough surface has a surface roughness of 80 to 400 nm. The nano metal substrate for FPC and COF materials according to claim 1, wherein the rough polyimine layer has a coarsened sublayer composed of an inorganic powder or a flame retardant compound powder. And the roughened sublayer constitutes a rough surface of the roughened polyimine layer. The nano metal substrate for FPC and COF materials according to claim 1, wherein the ultra-thin nano metal layer is a copper foil layer or a multilayer alloy metal layer composed of at least two metal layers. One of the at least two metal layers is a copper foil layer, and the other of the at least two metal layers is selected from the group consisting of a silver layer, a nickel layer, a chromium layer, a palladium layer, an aluminum layer, a titanium layer, a copper layer, and a molybdenum layer. And an indium layer, a platinum layer or a gold layer, wherein the copper foil layer has a thickness of 90 to 150 nm, and the other of the at least two metal layers has a thickness of 5 to 15 nm. The nano metal substrate for FPC and COF materials according to claim 11, wherein the ultrathin nano metal layer is a copper foil layer having a thickness of 0.1 to 0.2 μm. The nano metal substrate for FPC and COF materials according to claim 11, wherein the ultra-thin nano metal layer comprises: a copper foil layer having a surface opposite to the first copper foil and a second a copper foil surface; a first metal sublayer formed on a surface of the first copper foil of the copper foil layer, and the material forming the first metal sublayer is nickel; and a second metal sublayer formed on the copper a surface of the second copper foil of the foil layer, the copper foil layer being located between the first metal sublayer and the second metal sublayer, and the material forming the second metal sublayer is selected from the group consisting of nickel, silver or copper . The nano metal substrate for FPC and COF materials according to claim 2, wherein the protective layer is a carrier layer composed of a PET layer and a low adhesion layer formed on the surface of the PET layer. The carrier layer is attached to the surface of the ultra-thin nano metal layer through the low adhesion layer, wherein the PET layer has a thickness of 23 to 50 μm, the low adhesion layer has a thickness of 5 to 10 μm, and the low adhesion layer The release force is 1 to 5 g/cm. The nano metal substrate for FPC and COF materials according to claim 2, wherein the protective layer is a dry film layer comprising a photosensitive resin layer and a light transmissive layer, the photosensitive resin layer The light transmissive layer is covered on one side and the other surface is attached to the surface of the ultra-thin nano metal layer.