CN205603678U - flexible metal laminate - Google Patents

Abstract

A flexible metal laminate material provides a polyimide film; electrolessly plate a nickel metal layer with a thickness of 0.07-0.11 microns on at least one surface of the polyimide film; electroplate a first copper layer on the nickel metal layer; and electroplate a second copper layer on the first copper layer.

Description

flexible metal laminate

technical field

The utility model relates to a flexible metal laminated material, in particular to a flexible laminated material which can improve the process qualification rate and dimensional stability.

Background technique

Flexible copper clad laminate (Flexible copper clad laminate, FCCL) is widely used in the electronics industry as a circuit substrate (PCB). In addition to the advantages of lightness, thinness and flexibility, FCCL also has the advantages of using polyimide film. In addition to excellent electrical properties, thermal properties and heat resistance, its low dielectric constant (Dk) enables rapid transmission of electrical signals, good thermal properties, easy cooling of components, and high vitrification Temperature (Tg), which allows components to perform well at higher temperatures.

At present, flexible copper foil substrates usually form a nickel layer on the surface of the polyimide film by electroless plating, and then form a copper layer by electrolytic plating on it. This nickel layer is used as a barrier to prevent The method of copper diffusion into the polyimide film can provide good adhesion and reliability between the metal layer and the polyimide film.

However, when electroplating copper on the nickel layer, due to the high resistance value of nickel, when performing high-current electroplating copper, it will lead to uneven thickness of electroplated copper and color difference on the surface, resulting in poor quality.

Therefore, electroplating copper under the polyimide film with a nickel layer can make the copper layer adhere to the polyimide film more effectively, and can maintain good operability and process qualification rate in the continuous copper electroplating step And dimensional stability, is actually a topic to be studied.

Utility model content

The utility model relates to a flexible metal laminate, which is manufactured by the following method: it includes providing a polyimide film; forming a 0.07 to 0.11 micron nickel metal on the polyimide film by electroless plating layer; the polyimide film is subjected to a first electroplating to form a first copper layer on the nickel metal layer; the polyimide film is subjected to a second electroplating to form a secondary copper layer on the bottom copper .

In this way, the copper layer can be effectively attached to the nickel layer, and its thickness uniformity is good and there is no color difference and other appearance defects, and the first copper layer and the second copper layer can be continuously electroplated in the manufacturing process to maintain a good Operability, process pass rate and dimensional stability.

Description of drawings

Fig. 1 is the first schematic diagram of the flexible metal laminated material of the present invention;

Fig. 2 is the second schematic diagram of the flexible metal laminated material of the present invention;

Fig. 3 is the third schematic diagram of the flexible metal laminated material of the present invention;

Fig. 4 is a fourth schematic diagram of the flexible metal laminate of the present invention.

【Symbol Description】

Polyimide film 10

Nickel metal layer 12

First Copper Layer 14

Second Copper Layer 16

detailed description

Please refer to Fig. 1, which is the first schematic diagram of the flexible metal laminated material of the present invention, providing a polyimide film 10, the monomer composition and preparation method of the polyimide film are not particularly limited, and can be obtained by Common knowledge in the technical field is carried out, and details are not repeated here. The thickness of the polyimide film 10 can be 7-50 microns, and the surface treatment of the polyimide film 10 includes: alkaline surface modification, charge adjustment, catalyst treatment and activation, etc., which are not limited here . In one embodiment, the step of forming a metal layer on the surface of the polyimide film may include: surface treatment of the polyimide film with an alkali metal solution, catalyst treatment, and electroless nickel plating treatment .

Alkaline surface modification step can use alkaline metal solution, for example: alkali metal family (such as sodium hydroxide, potassium hydroxide) aqueous solution, alkaline earth family aqueous solution, ammoniacal water, organic amine compound aqueous solution etc., or aforementioned mixture, can impregnate or Treated by spraying. Catalyst treatment and activation steps can be used for example: polyimide film is immersed in tin protochloride (SnCl2), then immersed in palladium chloride (PdCl2) in hydrochloric acid acidic aqueous solution; or polyimide film is immersed in In the palladium/tin gel solution, the activation treatment is carried out with sulfuric acid or hydrochloric acid; this step is to form the metal catalyst palladium for electroless plating reaction on the surface.

Please refer to FIG. 2 , and then, electroless plating is performed on the above-mentioned surface-treated polyimide film 10 to form a nickel layer 12 on at least one surface. In this technical field, the electroless plating technology includes parameters such as reagent type, concentration, temperature, time, etc., which are well known, and are not particularly limited here, but can be carried out according to the conditions of each electroless plating solution. In an embodiment, Ni-P, Ni-B, pure Ni, etc. may be used for nickel plating. In one embodiment, Ni-P is used, preferably low-phosphorus nickel (less than 5% by weight (wt%) of phosphorus), and the phosphorus content of the formed nickel layer is about 2 to 4wt%.

The utility model adopts the way of single-time nickel plating to form a single-layer nickel layer on one surface of the polyimide film, and can also form single-layer nickel layers on the two surfaces of the polyimide film respectively. In an embodiment, the thickness is about 0.07 to 0.11 microns, such as 0.07, 0.1 microns, etc.

In one embodiment, the process of the present invention is carried out in a roll-to-roll manner. The roll-to-roll process is usually applied to flexible film processes and can be produced continuously.

After the nickel layer is formed, heat treatment is performed. Through this heat treatment step, the known problem of adhesion between the metal layer and the polyimide film (that is, insufficient high-temperature reliability of the peel strength between the two) can be improved. Through the heat treatment step, while maintaining the peel strength between the metal layer and the polyimide film, the pass rate of copper layer electroplating can be improved, and the operability of copper layer electroplating can be improved. Moreover, the utility model performs electroplating on a first copper layer and then electroplating on a second copper layer in the same production line under an appropriate nickel layer thickness, which can maintain good operability and process pass rate.

In an embodiment, the heat treatment temperature is between about 60°C and about 150°C, for example: 65°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, etc. , or the temperature between any two points mentioned above. In a preferred embodiment, the heat treatment temperature is 70°C to 130°C. In a more preferred embodiment, the heat treatment temperature is 90°C to 130°C.

In an embodiment, the treatment time of the heat treatment is less than 28 hours and greater than 2 hours, for example: 4 hours, 8 hours, 12 hours, 16 hours, 20 hours, 24 hours, 26 hours, etc., or between any two points above time. In a preferred embodiment, the treatment time is 12 hours to 24 hours. In a more preferred embodiment, it is 24 hours.

After the heat treatment, the thermogravimetric loss ratio of the nickel layer-polyimide film, that is, the ratio of the film weight after heat treatment to the film weight before heat treatment, was measured to be more than 1%. In one embodiment, the thermogravimetric loss ratio is 1% to 2%.

This heat treatment step can maintain the excellent peel strength retention rate between the polyimide film and the nickel layer. Here, the peel strength retention rate can be calculated by the following formula:

Peel strength retention (%)=(P1/P0)×100%

Wherein, P0 is the initial peel strength after the heat treatment step, and P1 is the peel strength after the heat treatment step and the aging step (150° C. for 168 hours). In an embodiment, the peel strength retention rate is about 50% or more, for example: 55%, 60%, 65%, 70%, 75% or more, or a range between any two points above. After the aforementioned heat treatment step is completed, a first copper layer and a second copper layer are subsequently electroplated on the nickel metal layer.

Please refer to Fig. 3, after completing the heat treatment step, the first electroplating is carried out in a vertical roll-to-roll manner, and the electrolytic solution is high-acid low-copper, so as to form a copper layer on the nickel metal layer 12, and the copper layer includes the first copper layer 14 and the second copper layer 16 , the first copper layer 14 is formed on the nickel metal layer 12 .

Please refer to FIG. 4 , after the first electroplating is completed, the second electroplating is performed in a continuous manner, and the electrolyte is low-acid high-copper, so as to form a second copper layer 16 on the first copper layer 14 .

In this way, when a first copper layer 14 and a second copper layer 16 are respectively formed on the nickel metal layer 12 by means of secondary electroplating, the copper layer can be made to have preferred uniformity and no color difference, so as to obtain a better process qualification rate and dimensional stability.

After the electroplating of the first copper layer 14 and the second copper layer 16 is completed, they are immersed in an organic antioxidant to perform an anti-oxidation treatment.

Example 1:

Electroless nickel plating step: surface treatment of the polyimide film with TAMACLEAN 110 reagent from Arakawa Chemical Industry Co., Ltd. at 35° C. for about 150 seconds. Then, the SLP process (SLP process, from Okuno Pharmaceutical Co., Ltd.) is used to perform the steps of electroless nickel plating such as surface charge adjustment, pre-dipping, catalysis, and acceleration. The SLP series reagents (including SLP-200, SLP-300, SLP -400, SLP-500, SLP-600) were purchased from Okuno Pharmaceutical Co., Ltd. to form a nickel metal layer 12 with a thickness of 0.07-0.11 microns on the surface of the polyimide film 10 .

Heat treatment step: bake the film at 90°C for 24 hours. In this way, a heat-treated polyimide composite film with a nickel metal layer 12 is obtained.

The first electroplating step: the heat-treated polyimide composite film is subjected to the first electroplating. The electroplating solution is high-acid and low-copper, which contains 200g/L of H ₂ SO ₄ , 55g/L of CuSO ₄ and 50ppm of chloride ions , the current density is 1.5ASD to form a first copper layer 14 with a thickness of 0.67 microns on the nickel layer 12 .

The second electroplating step: carry out the second electroplating, the electroplating solution is low-acid high-copper, which contains 150g/L of H ₂ SO ₄ , 120g/L of CuSO ₄ and 50ppm chloride ions, and the current density is 2ASD, so that the first copper On layer 14 is formed a second copper layer 16 having a thickness of 2.33 microns.

Dimensional stability tests were performed and 0.02% was obtained.

After the second electroplating step, the organic antioxidant can be soaked for an anti-oxidation treatment.

Example 2:

Make a polyimide composite film with a nickel metal layer through heat treatment identical to that of Example 1.

The first electroplating step: the heat-treated polyimide composite film is subjected to the first electroplating. The electroplating solution is high-acid and low-copper, which contains 200g/L of H ₂ SO ₄ , 55g/L of CuSO ₄ and 50ppm of chloride ions , with a current density of 2ASD, so that a first copper layer 14 with a thickness of 1.26 microns is formed on the nickel metal layer 12 .

The second electroplating step: carry out the second electroplating, the electroplating solution is low-acid high-copper, which contains 150g/L of H ₂ SO ₄ , 120g/L of CuSO ₄ and 50ppm chloride ions, and the current density is 3ASD, so that the first copper Layer 14 is formed with a second copper layer 16 having a thickness of 4.74 microns.

Dimensional stability tests were performed and 0.04% was obtained.

After the second electroplating step, the organic antioxidant can be soaked for an anti-oxidation treatment.

Example 3:

Make a polyimide composite film with a nickel metal layer through heat treatment identical to that of Example 1.

The first electroplating step: the heat-treated polyimide composite film is subjected to the first electroplating, and the electrolyte is high-acid and low-copper, which contains 200g/L of H ₂ SO ₄ , 55g/L of CuSO ₄ and 50ppm of chloride ions , with a current density of 2ASD, so that a first copper layer 14 with a thickness of 1.99 microns is formed on the nickel metal layer 12 .

The second electroplating step: carry out the second electroplating, the electrolyte is low-acid high-copper, which contains 150g/L of H ₂ SO ₄ , 120g/L of CuSO ₄ and 50ppm chloride ions, and the current density is 4ASD, so that the first copper Layer 14 is formed with a second copper layer 16 having a thickness of 7.01 microns.

Dimensional stability tests were performed and 0.05% was obtained.

After the second electroplating step, the organic antioxidant can be soaked for an anti-oxidation treatment.

Comparative example 1:

Make a polyimide composite film with a nickel metal layer through heat treatment identical to that of Example 1.

The first electroplating step: the heat-treated polyimide composite film is subjected to the first electroplating, and the electrolyte is high-acid and low-copper, which contains 200g/L of H ₂ SO ₄ , 55g/L of CuSO ₄ and 50ppm of chloride ions , the current density is 1.5ASD, so that a first copper layer 14 with a thickness of 0.53 microns is formed on the nickel layer 12 .

The second electroplating step: carry out the second electroplating, the electrolyte is low-acid high-copper, which contains 150g/L H ₂ SO ₄ , 120g/L CuSO ₄ and 50ppm chloride ions, and the current density is 2ASD so that the first copper layer 14 is formed with a second copper layer 16 with a thickness of 2.47 microns.

Dimensional stability tests were performed and 0.11% was obtained.

After the second electroplating step, the organic antioxidant can be soaked for an anti-oxidation treatment.

Comparative example 2:

Make a polyimide composite film with a nickel metal layer through heat treatment identical to that of Example 1.

The first electroplating step: the heat-treated polyimide composite film is subjected to the first electroplating. The electroplating solution is high-acid and low-copper, which contains 200g/L of H ₂ SO ₄ , 55g/L of CuSO ₄ and 50ppm of chloride ions , with a current density of 2ASD, so that a first copper layer 14 with a thickness of 1.11 μm is formed on the nickel metal layer 12 .

The second electroplating step: carry out the second electroplating, the electrolyte is low-acid high-copper, which contains 150g/L of H ₂ SO ₄ , 120g/L of CuSO ₄ and 50ppm chloride ions, and the current density is 3ASD, so that the first copper Layer 14 is formed with a second copper layer 16 having a thickness of 4.89 microns.

After the second electroplating step, the organic antioxidant can be soaked for an anti-oxidation treatment.

Dimensional stability tests were performed and 0.12% was obtained.

Comparative example 3:

Make a polyimide composite film with a nickel metal layer through heat treatment identical to that of Example 1.

The first electroplating step: the heat-treated polyimide composite film is subjected to the first electroplating. The electroplating solution is high-acid and low-copper, which contains 200g/L of H ₂ SO ₄ , 55g/L of CuSO ₄ and 50ppm of chloride ions , with a current density of 2ASD, so that a first copper layer 14 with a thickness of 1.68 microns is formed on the nickel metal layer 12 .

The second electroplating step: carry out the second electroplating, the electrolyte is low-acid high-copper, which contains 150g/L of H ₂ SO ₄ , 120g/L of CuSO ₄ and 50ppm chloride ions, and the current density is 4ASD, so that the first copper Layer 14 is formed with a second copper layer 16 having a thickness of 7.32 microns.

Dimensional stability tests were performed and 0.12% was obtained.

Form 1:

Dimensional stability test method:

According to the IPC-TM650 2.2.4c specification, use a 2D measuring instrument (model M-4030-PC, purchased from Quanhong Precision) to measure.

The heat-treated composite film is electrolytically plated to form a first copper layer 14 on the nickel metal layer 12, and then electrolytically plated on the first copper layer 14 to form a second copper layer 16 to prepare a flexible Metal laminated materials (FCCL).

When the ratio of the thickness of the first copper layer 14 to the thickness of the total copper (first copper layer 14+second copper layer 16 ) of the present invention is greater than or equal to 20%, better dimensional stability can be obtained. When the thickness ratio is less than 20%, there is a problem that the dimensional stability is not good. The commonly used standard in the industry is that the dimensional stability needs to be less than 0.1%.

The technology of the utility model can effectively reduce the production cost, and is easy to operate and has a high qualified rate of products. And according to the process of the utility model, excellent flexible metal laminates can be prepared, which can achieve good thermal stability, good adhesion between layers (that is, high peel strength), anti-moisture absorption, anti-aging, easy to etch, and light and thin products. , which is conducive to subsequent applications such as construction materials and packaging materials for electronic components.

The content of the specific embodiments above is to describe the present utility model in detail, however, these embodiments are only for illustration, and are not intended to limit the present utility model. Those skilled in the art can understand that various changes or modifications made to the present utility model fall into a part of the present utility model without departing from the scope defined by the appended claims.

Claims (3)

1. A flexible metal laminate, characterized in that it comprises: a polyimide film; a nickel metal layer formed on at least one surface of the polyimide film; a copper layer comprising a first copper layer and a second copper layer, the first copper layer being located on the nickel metal layer; and The second copper layer is located on the first copper layer. 2. The flexible metal laminate according to claim 1, wherein the first copper layer has a smaller thickness than the second copper layer. 3 . The flexible metal laminate as claimed in claim 1 , wherein a thickness ratio of the first copper layer to the copper layer is greater than or equal to 20%. 4 .