TWI573687B - Laminated substrate and manufacturing method thereof - Google Patents

Description

Laminated board and manufacturing method thereof

The present invention relates to a substrate and a method of fabricating the same, and more particularly to a laminate and a method of making the same.

Flexible printed circuit boards are flexible, three-dimensionally spliced to reduce volume and light weight. Among them, the soft polyamide substrate has an adjustable thickness, excellent heat resistance, electrical insulation and mechanical properties, and its application and demand are increasing day by day. When the demand for electronic products is multi-functional, high-performance, thin and lightweight, high-density packaging materials and process technology critically affect process yield, product reliability and user reliability.

With the high-density package design, the demand for narrow line width spacing processes is increasing. For example, when the line width is less than 20 μm, the thickness of the metal layer such as the copper film must be less than 5 μm, and the three-layer soft board substrate (3L-FCCL) can no longer meet the demand, so the two-layer soft board substrate (2L- FCCL) has become mainstream. However, today's 2L-FCCL for high-density construction is produced by sputtering, which is expensive and compared to the coating method. Or pressing, the adhesion between the metal layer formed by the sputtering method and the substrate is poor. Therefore, in the fabrication process, the two-layer soft board substrate is susceptible to process yield and product reliability due to other high temperature steps. In addition, the use of 2L-FCCL can only use the subtraction method when making fine lines, resulting in limited thinning capability.

The present invention provides a laminate in which the substrate and the metal layer have good adhesion.

The invention further provides a method for manufacturing a laminate, which has good adhesion between the substrate and the metal layer.

The laminate of the present invention comprises a substrate, a first metal layer and a second metal layer. The material of the substrate is polyamidamine or polyamine. The first metal layer is disposed at a surface of the substrate, and the first metal layer includes a metal and a decane compound selected from the group consisting of Pd, Ni, Pt, and combinations thereof, and the metal particles have an average particle size distribution of less than 15 nm. The second metal layer is disposed on the first metal layer.

The method for producing a laminate of the present invention comprises the following steps. First, a substrate is provided, the material of which is polyamidamine or polyamine. Next, the substrate is subjected to an alkali modification treatment. Then, the substrate is impregnated with a first metal precursor solution to form a first metal precursor layer at the surface of the substrate, wherein the first metal precursor solution comprises a metal ion and a decane compound, and the metal ion is reduced. The potential is -0.3~2V. Then, the first metal precursor layer is reduced to form a first metal layer at the surface of the substrate, and the average particle size distribution of the metal particles in the first metal layer is less than 15nm. Then, a second metal layer is formed on the first metal layer.

The above described features and advantages of the invention will be apparent from the following description.

100‧‧‧ laminate

102‧‧‧Substrate

102a‧‧‧ surface

104‧‧‧First metal precursor layer

106‧‧‧First metal layer

106a‧‧‧ metal particles

108‧‧‧Second metal layer

110‧‧‧ Third metal circuit layer

1A-1E are schematic cross-sectional views showing a method of fabricating a laminate according to an embodiment of the invention.

2A to 2C are transmission electron micrographs of the examples of the present invention and the samples of Reference Examples 1 and 2.

3A to 3C are transmission electron micrographs of the examples of the present invention and the samples of Reference Examples 1 and 2.

1A-1E are schematic cross-sectional views showing a method of fabricating a laminate according to an embodiment of the invention. Referring to FIG. 1A, first, a substrate 102 is provided. In this embodiment, the substrate 102 can be a polyimide substrate or a polyamide substrate.

Next, the substrate 102 is subjected to an alkali modification treatment. In the present embodiment, the alkali reforming treatment is, for example, ring-opening activation of polyammonium or polyamine in the substrate 102. The alkali reforming treatment is, for example, a solution using an inorganic hydroxide salt such as potassium hydroxide or sodium hydroxide or an organic hydroxide salt such as tetramethylammonium hydroxide as an active ingredient. Wherein the concentration of the alkali compound used is, for example, 0.1 to 10 mol/L, and the temperature is as an example Such as room temperature to 100 ° C. Further, the time of the alkali reforming treatment is, for example, 5 seconds to 30 minutes. If the time of the alkali reforming treatment is too long, the surface of the substrate is excessively activated, the strength of the substrate is weakened, and the deposition of the metal layer is too deep into the surface of the substrate, which tends to cause etching residue. If the time of the alkali reforming treatment is too short, the hydrophilicity of the substrate is insufficient and the metal is not easily deposited. In one embodiment, the thickness of the metal layer deposited deep into the surface of the substrate is, for example, less than about 50 nm. In one embodiment, in order to increase the efficiency of the alkali reforming treatment, an alcohol such as methanol, ethanol, or propanol or an amine such as monoethanolamine may be added to the alkali solution to be used.

Referring to FIG. 1B, the substrate 102 is then impregnated with a first metal precursor solution to form a first metal precursor layer 104 at the surface 102a of the substrate 102, wherein the first metal precursor solution includes a metal ion. With decane compounds, the standard reduction potential of metal ions is -0.3~2V. Since the metal ion acts as a catalytic metal ion, this step is essentially a step of imparting a catalytic metal ion. In the present embodiment, the metal ion is, for example, selected from the group consisting of Pd ²⁺ , Ni ²⁺ , Pt ^{2+ ,} and combinations thereof. The first metal precursor solution includes, for example, a metal salt solution and a decane compound, wherein the metal salt may be PdCl ₂ , NiSO ₄ , PtCl ₄ , and the decane compound is, for example, an epoxy sulfonate compound or a paraffin decane compound, for example, The amine-free decane compound, and the decane compound present in the first metal precursor solution may be a single decane compound or a mixture comprising at least two decane compounds. The concentration of the decane compound in the first metal precursor solution is, for example, from 0.1 to 1 v/v%. If the concentration of the decane compound is too high, the ability to further improve the adhesion is limited, which in turn causes an unnecessary increase in cost. Conversely, if the concentration of the decane compound is too low, the adhesion can not be achieved. In this step, the substrate 102 is immersed in the first metal precursor solution such that metal ions such as Pd ²⁺ are adsorbed on the surface of the substrate 102. In particular, a portion of the first metal precursor solution will penetrate into the substrate 102, so that a portion of the first metal precursor layer 104 will be located in the substrate 102, that is, a portion of the first metal precursor. Layer 104 is located on surface 102a of substrate 102.

Referring to FIG. 1C, the first metal precursor layer 104 is reduced to form a first metal layer 106 at the surface of the substrate 102. The average particle size distribution of the metal particles 106a in the first metal layer 106 is less than 15 nm. This step is a reduction step such that the catalytic metal ions in the first metal precursor layer 104 are reduced to metal. In the present embodiment, the method of reducing the first metal precursor layer 104 is, for example, immersing the substrate 102 in a reducing solution such that metal ions in the first metal precursor layer 104 are reduced to metal. The reducing solution is, for example, a solution of dimethylamine borane, sodium borohydride or sodium hypophosphite, and the metal is, for example, a Pd metal. Among them, the decane compound causes the metal ions to more closely bond to the organic carbon chain of the substrate after reduction, thereby greatly enhancing the adhesion between the first metal layer 106 and the substrate 102. The thickness of the first metal layer 106 on the surface 102a of the substrate 102 is, for example, less than 100 nm, and is, for example, less than 50 nm. In the substrate 102, the decane compound is, for example, located only adjacent to the surface 102a of the substrate 102.

Referring to FIG. 1D, a second metal layer 108 is formed on the first metal layer 106. In the present embodiment, the method of forming the second metal layer 108 is, for example, an electroless plating process such as an electroless plating process. The material of the second metal layer 108 is, for example, selected from the group consisting of Ni, Cu, Co and combinations thereof.

In this embodiment, after the second metal layer 108 is formed, the second metal layer 108 may be further subjected to a heat treatment. The temperature of the heat treatment is, for example, 150 to 200 ° C, and the treatment time is, for example, 10 to 60 minutes.

Referring to FIG. 1E, in the embodiment, a third metal wiring layer 110 is further formed on the second metal layer 108. In the present embodiment, the third metal wiring layer 110 is formed by, for example, directly forming a metal layer on the second metal layer 108 by a wet process such as an electroplating process, and then using a subtractive method to form a wiring. In another embodiment, the third metal wiring layer 110 may also be formed on the second metal layer 108 by an additive method or a semi-additive method to form a line having a small line width. The material of the third metal wiring layer 110 is, for example, Cu or other suitable metal. In an embodiment, after the third metal circuit layer 110 is formed, the third metal circuit layer 110 may be further subjected to a heat treatment. The temperature of the heat treatment is, for example, 150 to 200 ° C, and the treatment time is, for example, 10 to 60 minutes. If the temperature of the aforementioned heat treatment is too high, copper is easily oxidized. If the temperature of the heat treatment is too low, it does not contribute to the increase in adhesion. If the time of the aforementioned heat treatment is too long, copper is easily oxidized and the crystal phase structure changes. If the heat treatment time is too short, it will not help the adhesion increase. In the present embodiment, the interface bonding force between the first metal layer 106 and the second metal layer 108 and the third metal wiring layer 110 to the substrate 102 is, for example, greater than 0.8 Kgf/cm.

In the present embodiment, as shown in FIG. 1E, the laminate 100 includes a substrate 102, a first metal layer 106, and a second metal layer 108. The material of the substrate 102 is polyamidamine or polyamine. The first metal layer 106 is disposed at the surface of the substrate 102. In this embodiment The first metal layer 106 includes a metal and a decane compound selected from the group consisting of Pd, Ni, Pt, and combinations thereof, and the metal particle 106a- has an average particle size distribution of less than 15 nm. The second metal layer 108 is disposed on the first metal layer 106. In the embodiment, the laminated board 100 further includes a third metal circuit layer 110 disposed on the second metal layer 108. In particular, in the present embodiment, the laminated board 100 shown in FIG. 1D or FIG. 1E is produced by the above-described flow, but the present invention is not limited thereto. In other words, in other embodiments, the laminate 100 as shown in FIG. 1D or FIG. 1E may be fabricated by other processes.

In the present embodiment, the substrate 102 is pretreated with a first metal precursor solution to form a first metal layer 106 as a catalytic metal layer at the surface of the substrate 102 prior to forming the second metal layer 108. Wherein the decane compound in the first metal precursor solution causes the metal ions to closely bond to the organic carbon chain of the substrate after reduction, and forms metal particles 106a having an average particle size distribution of less than 15 nm. Therefore, the first metal layer 106 and the substrate 102 have good adhesion, thereby enhancing the adhesion between the second metal layer 108 and the substrate 102. As a result, the laminated board 100 has better process yield and reliability.

On the other hand, the first metal layer 106 has a good bonding force between the second metal layer 108 and the substrate 102, so that the third metal wiring layer 110 formed on the second metal layer 108 and the substrate 102 are also Has a good combination of strength. As a result, the third metal wiring layer 110 can have good thinning ability and fine line yield. For example, the third metal wiring layer 110 can be fabricated using a wet process having a lower cost than the sputtering method. Further, the thickness of the third metal wiring layer 110 can be easily adjusted for customization, and the high-density stacked laminate 100 can be fabricated. Therefore, using the product The flexible circuit substrate of the laminate 100 has better yield and reliability and lower manufacturing cost.

The above and other objects, features, and advantages of the present invention will become more apparent and understood. The solution used for nickel plating and its conditions are as follows.

<alkali modification treatment>

Use solution: 1mol/L potassium hydroxide

Processing temperature: 40 ° C

Processing time: 5 minutes

<catalyst attached>

Use solution: 0.4g / L palladium chloride

Processing temperature: room temperature

Processing time: 2 minutes

<catalyst reduction>

Use solution: 0.2mol/L sodium hypophosphite

Processing temperature: room temperature

Processing time: 2 minutes

<electroless nickel plating>

Use solution: SlottoNIP-30

Processing temperature: 80 ° C

Processing time: 0.5 minutes

Example

A commercially available DuPont polyamine substrate (Kapton PI film) is provided. Next, the polyiminamide substrate was subjected to an alkali modification treatment using a KOH solution. Then, the substrate was immersed in an aqueous PdCl ₂ solution containing a decane compound having a concentration of 0.5 v/v% to carry out catalyst attachment. Then, the substrate is subjected to a catalyst reduction treatment to form a Pd layer at the surface of the substrate. Thereafter, a Ni metal layer is formed on the Pd layer.

Reference example 1

A mixed polyamidene substrate modified with silica is provided. Next, the mixed polyamidamide substrate was subjected to alkali reforming treatment using a KOH solution. Then, the substrate was immersed in an aqueous solution of PdCl ₂ containing no decane compound to carry out catalyst attachment. Then, the substrate is subjected to a catalyst reduction treatment to form a Pd layer at the surface of the substrate. Thereafter, a Ni metal layer is formed on the Pd layer.

Reference example 2

In Reference Example 2, the substrate was treated in the same manner as in the examples except that the PdCl ₂ aqueous solution contained no decane compound.

After the substrate was treated in accordance with the procedures described in the Examples and Reference Examples 1 and 2 to obtain a sample, each sample of the Examples and Reference Examples 1 and 2 was observed using a transmission electron microscope, and Pd metal particles were observed in each sample. Distribution results, the results are shown in Figures 2A to 2C and Figures 3A to 3C, respectively.

Referring to FIG. 2A to FIG. 2C and FIG. 3A to FIG. 3C simultaneously, in Reference Example 1 (FIG. 2A), the thickness of the Ni metal layer on the surface of the PI substrate is about 60 nm, and the Ni metal infiltrated into the substrate. The thickness of the layer is approximately 435 nm. In Reference Example 2 (Fig. 2B), The thickness of the Ni metal layer on the surface of the PI substrate was about 70 nm, and the thickness of the Ni metal layer penetrating into the substrate was about 35 nm. In the embodiment (Fig. 2C), the thickness of the Ni metal layer on the surface of the PI substrate was about 65 nm, and the thickness of the Ni metal layer penetrating into the substrate was about 40 nm. From the above results, the depth of penetration of the Pd metal particles of Reference Example 1 into the PI substrate was greatly affected by the alkali treatment, and the depth of the Pd metal particles of Reference Example 2 and the Example penetrated into the PI substrate was affected by the alkali treatment. Smaller.

Further, in Reference Example 1 (Fig. 3A) and Reference Example 2 (Fig. 3B), Pd metal particles agglomerated to form larger particles. However, in the embodiment (Fig. 3C), the Pd metal particles hardly agglomerate and are uniformly distributed at the surface of the substrate, wherein the Pd metal particles have an average particle diameter of less than 15 nm. Therefore, the amount of palladium used can be reduced and the cost can be reduced. On the other hand, in the reference example 1, the thickness of the Ni metal layer which penetrated into the substrate was so deep that Pd/Ni easily remained in the PI substrate, and the electrical properties of the laminated plate were affected. On the other hand, in the Pd/Ni of the examples, the thickness of the Ni metal layer which penetrated into the substrate was shallow, and it would not easily remain in the PI substrate. It can be seen that the addition of the decane compound to the metal precursor solution enables the metal ions to be uniformly distributed on the substrate after reduction and has a small average particle diameter, and the metal particles are less likely to remain in the substrate.

Next, the interface bonding force between the Ni metal layer and the PI substrate in the samples of the Example and the Reference Example 2 was tested. In detail, the interfacial adhesion between the Ni metal layer and the PI substrate under the conditions of the untreated, heat-treated, and aged treatments of the samples of the tensile test machine test example and the reference example 2, respectively. Among them, the heat treatment was baked at 180 ° C for 1 hour. The aging treatment was carried out at 150 ° C for 168 hours. Table 1 below shows the Ni metal layer and the PI substrate in the sample treated under each condition. Interface bonding.

As is clear from Table 1, in the example in which decane was added, the interface bonding force between the Ni metal layer and the PI substrate was large as compared with Reference Example 2 in which decane was not added. Further, even after the aging treatment, the Ni metal layer in the embodiment in which decane is added still has a uniform interfacial bonding force with the PI substrate. From the above results, it is known that the addition of decane to the metal precursor solution can enhance the interfacial bonding force between the substrate and the catalytic metal layer.

In summary, the present invention pretreats a substrate using a metal precursor solution containing a decane compound to form a first metal layer as a catalytic metal layer at the surface of the substrate. Wherein the decane compound causes the metal ion to more closely bind to the organic carbon chain of the substrate after reduction, and the metal particle has an average particle diameter of less than 15 nm. The distribution, therefore, has a good bonding force between the substrate and the first metal layer, thereby improving the adhesion between the substrate and the second metal layer.

In this way, when the third metal circuit layer is formed on the second metal layer, the substrate and the metal wire also have a good bonding force, so that the third metal circuit layer can have good thinning ability and fine line. rate. In addition, the interface bonding force between the substrate and the catalytic metal layer in the laminate is not easily affected by high temperature, and thus the laminate is not easily damaged by the high temperature step in the subsequent process. Therefore, the laminate has better process yield and reliability and lower manufacturing costs.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧ laminate

102‧‧‧Substrate

102a‧‧‧ surface

106‧‧‧First metal layer

106a‧‧‧ metal particles

108‧‧‧Second metal layer

110‧‧‧ Third metal circuit layer

Claims (23)

A laminated board comprising: a substrate, the material of which is polyamidamine or polyamine; a first metal layer disposed at a surface of the substrate, the first metal layer comprising a selected from the group consisting of Pd, Ni, Pt And a metal and a decane compound thereof, wherein the metal particles have an average particle size distribution of less than 15 nm, wherein the decane compound and the metal are mixed together to form a single layer; and a second metal layer is disposed at the first On the metal layer. The laminate according to claim 1, wherein the interface bonding force between the substrate and the second metal layer is greater than 0.8 Kgf/cm. The laminate according to claim 1, wherein the first metal layer has a thickness of less than 100 nm. The laminate according to claim 3, wherein the first metal layer has a thickness of less than 50 nm. The laminate according to claim 1, wherein the material of the second metal layer is selected from the group consisting of Ni, Cu, Co, and combinations thereof. The laminated board according to claim 1, further comprising a third metal circuit layer disposed on the second metal layer. The laminate according to claim 6, wherein the material of the third metal wiring layer comprises Cu. A method for manufacturing a laminate, comprising: providing a substrate, the material of which is polyamidamine or polyamine; performing an alkali modification on the substrate; impregnating the substrate with a first metal precursor solution, Forming a first metal precursor layer at a surface of the substrate, wherein the first metal precursor solution comprises a metal ion and a decane compound, and the standard reduction potential of the metal ion is -0.3~2V; a metal precursor layer to form a first surface at the surface of the substrate a metal layer, wherein the metal particles in the first metal layer have an average particle size distribution of less than 15 nm; and a second metal layer is formed on the first metal layer. The method for producing a laminate according to claim 8, wherein the metal ion is selected from the group consisting of Pd ²⁺ , Ni ²⁺ , Pt ²⁺ and combinations thereof. The method for fabricating a laminated board according to claim 8, wherein an interface bonding force between the substrate and the first metal layer is greater than 0.8 Kgf/cm. The method for producing a laminate according to the invention of claim 8, wherein the alkali reforming time is from 5 seconds to 30 minutes. The method for producing a laminate according to claim 8, wherein the decane compound of the first metal precursor solution is a single decane compound or a mixture comprising at least two decane compounds. The method for producing a laminate according to claim 8, wherein the decane compound of the first metal precursor solution is at least one selected from the group consisting of an epoxy sulfonate compound and a paraffin decane compound. The method for producing a laminate according to claim 8, wherein the decane compound of the first metal precursor solution is an amine group-free decane compound. The method for producing a laminate according to claim 8, wherein the concentration of the decane compound of the first metal precursor solution is between 0.1 and 1 v/v%. The method for fabricating a laminate according to claim 8, wherein after the forming the second metal layer, further comprising performing a heat treatment. The method for producing a laminate according to claim 16, wherein the heat treatment has a temperature of from 150 to 200 ° C and a treatment time of from 10 to 60 minutes. The method for fabricating a laminate according to claim 8, wherein the method of forming the second metal layer comprises an electroless plating process. The method for fabricating a laminate according to claim 8, wherein the material of the second metal layer is selected from the group consisting of Ni, Cu, Co, and combinations thereof. The method for fabricating a laminated board according to claim 8, further comprising a third metal wiring layer on the second metal layer. The method for fabricating a laminated board according to claim 20, wherein after forming the third metal wiring layer, further comprising performing a heat treatment. The method for producing a laminate according to claim 21, wherein the heat treatment has a temperature of from 150 to 200 ° C and a treatment time of from 10 to 60 minutes. The method for fabricating a laminate according to claim 20, wherein the method for forming the third metal wiring layer comprises an electroplating process.