TWI793745B - Low-dissipation and high dimensional stability flexible copper clad laminate, manufacturing method thereof, and electronic device - Google Patents

Abstract

The present disclosure provides a low-dissipation and high dimensional stability flexible copper clad laminate. The low-dissipation and high dimensional stability flexible copper clad laminate includes a copper foil and a polyimide film. The polyimide film is connected to the copper foil, and includes a polyimide. The polyimide has a structure represented by formula (I), in which each symbol is as defined in the specification. Thus, the flexible copper clad laminate prepared by using the polyimide of the present disclosure has an extra low dissipation factor and a thermal expansion coefficient similar to that of the copper foil.

Description

Flexible copper foil substrate with low dielectric loss and high dimensional stability, its preparation method and electronic device

The present invention relates to a flexible copper foil substrate, its preparation method and electronic device, in particular to a flexible copper foil substrate with low dielectric loss and high dimensional stability, its preparation method and electronic device.

Since the International Telecommunication Union (ITU) officially announced the vision of 5G communication (5 ^th Generation Mobile Network) in 2015, various relevant units have successively developed new technologies and materials, and for the new generation of communication networks, it is necessary to achieve high Transmission rate, high stability, low latency and low transmission loss are expected.

式(1)、

式(2)。 Printed circuit board (PCB) is mainly used in communications, automobiles, semiconductors and other electronic products to fix integrated circuits (Integrated Circuit, IC) and other electronic components, and use copper wires to connect electronic signals Transmission between different components, according to the known literature, the signal transmission rate (V _p ) is inversely proportional to the square root of the material permittivity (D _k ), such as formula (1); and the signal transmission loss (L) is proportional to the dielectric constant The square root of the constant (D _k ) and the dielectric loss (D _f ), such as formula (2), so to become a new generation of high-frequency communication substrate, the material must have excellent thermal properties, electrical properties, and high chemical resistance And low humidity, and in order to achieve high transmission rate and low transmission loss, reducing the dielectric constant (D _k ) and dielectric loss (D _f ) of the material is the goal of development.

Formula 1),

Formula (2).

Common printed circuit boards include flexible printed circuit boards, which are generally made of polyimide and copper foil, and the electrical properties are closely related to polyimide. The most common polyimide on the market is DuPont's Kapton, and its dielectric loss is about 0.016. Therefore, the conventional polyimide can no longer meet the requirements of high-frequency signal transmission and high-speed computing of circuit boards.

In view of this, how to synthesize a polyimide with low dielectric loss, and the flexible copper foil substrate prepared by it can be applied to the production of high-frequency transmission printed circuit boards, has become the goal of related industry efforts.

One object of the present invention is to provide a flexible copper foil substrate with low dielectric loss and high dimensional stability and its preparation method, utilizing the linear characteristics of the molecular chains of diamine and dianhydride to synthesize polyimide It has low dielectric loss and low thermal expansion coefficient, and is applied to flexible copper foil substrates.

式(I)， 其中，A ₁為式(I-1)所示之一結構，A ₂為式(I-2)所示之一結構，A ₃為式(I-3)所示之一結構，A ₄為式(I-4)所示之一結構：

式(I-1)、

式(I-2)、

式(I-3)、

式(I-4)， 其中，R及Q各自獨立為氫、碳數1至6的烷基、三氟甲基、苯基或鹵素基，x、y、z及q為整數或小數，n為聚合度，其滿足下列條件：0 ＜ x ＜ 1；0 ≤ y ≤ 1；0 ≤ z ≤ 1；0 ≤ q ≤ 1；x+y+z+q = 1；以及1 ≤ n ≤ 500。 One embodiment of the present invention provides a flexible copper foil substrate with low dielectric loss and high dimensional stability, which includes a copper foil and a polyimide film. The polyimide film is bonded to the copper foil and contains a polyimide. Polyimide has one structure as shown in formula (I):

Formula (I), Wherein, A ₁ is a structure shown in formula (I-1), A ₂ is a structure shown in formula (I-2), A ₃ is a structure shown in formula (I-3), A ₄ is One structure shown in formula (I-4):

Formula (I-1),

Formula (I-2),

Formula (I-3),

Formula (I-4), Wherein, R and Q are each independently hydrogen, alkyl, trifluoromethyl, phenyl or halogen group with 1 to 6 carbons, x, y, z and q are integers or decimals, n is the degree of polymerization, which satisfies the following Conditions: 0 < x <1; 0 ≤ y ≤ 1; 0 ≤ z ≤ 1; 0 ≤ q ≤ 1; x+y+z+q = 1; and 1 ≤ n ≤ 500.

式(I-A)。 According to the flexible copper foil substrate with low dielectric loss and high dimensional stability described in the previous paragraph, when in formula (I), R is hydrogen and x+z is 1, the polyamide contained in the polyimide film Imines can have one of the structures shown in formula (IA):

Formula (IA).

式(I-B)， 其中Q為甲基或三氟甲基。 According to the flexible copper foil substrate with low dielectric loss and high dimensional stability described in the previous paragraph, when in formula (I), R is hydrogen and x+y is 1, the polyamide contained in the polyimide film Imines can have one of the structures shown in formula (IB):

Formula (IB), Wherein Q is methyl or trifluoromethyl.

式(I-C)。 According to the flexible copper foil substrate with low dielectric loss and high dimensional stability described in the previous paragraph, when in formula (I), R is hydrogen and x+q is 1, the polyamide contained in the polyimide film Imines can have one of the structures shown in formula (IC):

Formula (IC).

According to the flexible copper foil substrate with low dielectric loss and high dimensional stability mentioned above, the thermal expansion coefficient of the polyimide film can be 9 ppm/ ^o C to 33 ppm/ ^o C.

According to the flexible copper foil substrate with low dielectric loss and high dimensional stability mentioned above, the dielectric loss of the polyimide film can be less than 0.0025.

式(i)、 式(ii-1)、 式(ii-2)、 式(ii-3)、

式(ii-4)、 式(iii)， 其中，R為氫、碳數1至6的烷基、三氟甲基、苯基或鹵素基。縮合反應係將聚醯胺酸溶液塗佈至銅箔上，並進行加熱閉環後，以獲得具低介電損失及高尺寸安定性的軟性銅箔基板。 Another embodiment of the present invention provides a method for preparing the aforementioned flexible copper foil substrate with low dielectric loss and high dimensional stability, including performing a mixing step and performing a condensation reaction. The mixing step is to combine a diamine monomer as shown in formula (i) and a diamine monomer as shown in formula (ii-1), such as formula (ii-2), such as formula (ii-3) or such as formula (ii-4) After the diamine monomer shown is dissolved in an organic solvent, a dianhydride monomer as shown in formula (iii) is added to form a polyamic acid solution after mixing:

Formula (i), Formula (ii-1), Formula (ii-2), Formula (ii-3),

Formula (ii-4), Formula (iii), Wherein, R is hydrogen, alkyl having 1 to 6 carbons, trifluoromethyl, phenyl or halogen. The condensation reaction is to apply the polyamic acid solution on the copper foil, and after heating and closing the loop, a flexible copper foil substrate with low dielectric loss and high dimensional stability can be obtained.

According to the method for preparing a flexible copper foil substrate with low dielectric loss and high dimensional stability described above, the organic solvent can be dimethylacetamide, dimethylformamide or N-methylpyrrolidone.

According to the preparation method of the flexible copper foil substrate with low dielectric loss and high dimensional stability described in the previous paragraph, wherein the diamine monomer shown in formula (i) is added with formula (ii-1), formula ( The molar ratio of ii-2), the diamine monomer represented by formula (ii-3) or formula (ii-4) and the dianhydride monomer represented by formula (iii) may be 0.9 to 1.1.

Yet another embodiment of the present invention provides an electronic device, which includes the aforementioned flexible copper foil substrate with low dielectric loss and high dimensional stability.

Thus, the flexible copper foil substrate prepared by the polyimide of the present invention has low dielectric constant, low dielectric loss, low thermal expansion coefficient and low manufacturing cost, which not only meets the needs of the industry, but is also suitable for electronic devices .

Various embodiments of the invention are discussed in more detail below. However, this embodiment may be an application of various inventive concepts, and may be embodied in various specific ranges. The specific embodiments are for illustrative purposes only and do not limit the scope of the disclosure.

In the present invention, the compound structure is sometimes represented by a skeleton formula, and carbon atoms, hydrogen atoms, and carbon-hydrogen bonds can be omitted in this representation. If there is a clearly drawn functional group in the structural formula, the drawn one shall prevail.

In the present invention, "polyimide having a structure as shown in formula (I)" is sometimes expressed as polyimide or polyimide shown in formula (I) for the sake of brevity and clarity. (I), the representation of other compounds or groups can be deduced by analogy.

＜Polyimide＞

式(I)， 其中，A ₁為式(I-1)所示之一結構，A ₂為式(I-2)所示之一結構，A ₃為式(I-3)所示之一結構，A ₄為式(I-4)所示之一結構：

式(I-1)、

式(I-2)、

式(I-3)、

式(I-4)， 其中，R及Q各自獨立為氫、碳數1至6的烷基、三氟甲基(-CF ₃)、苯基或鹵素基，x、y、z及q為整數或小數，n為聚合度，其滿足下列條件：0 ＜ x ＜ 1；0 ≤ y ≤ 1；0 ≤ z ≤ 1；0 ≤ q ≤ 1；x+y+z+q = 1；以及1 ≤ n ≤ 500，具體地，本發明之聚醯亞胺的完整結構如下表一所示。 表一

Polyimide of the present invention has a structure as shown in formula (I):

Formula (I), Wherein, A ₁ is a structure shown in formula (I-1), A ₂ is a structure shown in formula (I-2), A ₃ is a structure shown in formula (I-3), A ₄ is One structure shown in formula (I-4):

Formula (I-1),

Formula (I-2),

Formula (I-3),

Formula (I-4), Wherein, R and Q are each independently hydrogen, alkyl with 1 to 6 carbons, trifluoromethyl (-CF ₃ ), phenyl or halogen, x, y, z and q are integers or decimals, and n is a polymer degree, which satisfies the following conditions: 0 < x <1; 0 ≤ y ≤ 1; 0 ≤ z ≤ 1; 0 ≤ q ≤ 1; x+y+z+q = 1; and 1 ≤ n ≤ 500, specifically , the complete structure of the polyimide of the present invention is shown in Table 1 below. Table I

Specifically, the material with the lowest dielectric loss on the market is Liquid Crystal Polyester (LCP). At 10 GHz, its dielectric loss can reach less than 0.0025, because the liquid crystal polyester has a local forward Alignment and low polarity of the ester group, resulting in its low dielectric loss characteristics. Therefore, in order to achieve low dielectric loss in polyimide, the molecular chain of polyimide must have linear characteristics, and the selected monomers must also be linear.

式(a-1)、 式(a-2)、 式(a-3)。 Please refer to Fig. 1A, Fig. 1B, Fig. 1C, Fig. 1D, Fig. 1E, Fig. 1F and Fig. 1G, which are diagrams showing the molecular chain arrangement structure. Specifically, if the molecular chain arrangement structure is too linear, it will lead to poor processability, or poor mechanical properties of the film (insufficient toughness), as shown in Figure 1A, the corresponding structure can be but not limited to formula (a-1), the structure shown in formula (a-2) or formula (a-3), therefore, it is necessary to introduce a monomer of nonlinear or side chain group to increase its processability or the mechanical properties of the film, as shown in the first paragraph Figure 1B, Figure 1C, Figure 1D, Figure 1E, Figure 1F and Figure 1G, wherein R in Figure 1F and Figure 1G represents a substituent.

Formula (a-1), Formula (a-2), Formula (a-3).

The common polyimide Kapton (DuPont) is composed of 4,4'-diaminodiphenyl ether (4,4'-oxydianiline, 4,4'-ODA) and pyromellitic anhydride (pyromellitic anhydride, PMDA), although the molecular formulas of liquid crystal polymers and polyimide are different, but the arrangement is the same, so the arrangement of liquid crystal polymers can be used to simulate the molecular arrangement of polyimide.

式(b-1)、 式(b-2)、 式(b-3)。 For example, if the polyimide molecular chains are arranged as shown in Figure 1B, the corresponding structure can be but not limited to formula (b-1), formula (b-2) or formula (b-3) The structure shown shows that when 4,4'-ODA is selected as the reaction monomer to react with acid anhydride, the linearity of the polyimide molecular chain will be greatly reduced.

Formula (b-1), Formula (b-2), Formula (b-3).

式(c-1)、 式(c-2)。 In addition, if the polyimide molecular chains are arranged as shown in Figure 1C, the corresponding structure can be but not limited to the structure shown in formula (c-1) or formula (c-2), indicating that when 3, 4'-diaminodiphenyl ether (3,4'-oxydianiline, 3,4'-ODA) or 4,4'-diaminobenzophenone (4,4'-diaminobenzophenone) as the reaction monomer and When the acid anhydride is reacted, compared to the arrangement shown in Figure 1A, the processability or mechanical properties of the film can be improved, and the linearity of the molecular chain can still be maintained compared to the arrangement shown in Figure 1B. However, the polarity of the carbonyl group of 4,4'-diaminobenzophenone is high, which is not conducive to dielectric loss, and the carbonyl group is an electron-withdrawing group, which will cause low reactivity of diamine, which is not conducive to polymerization into polymers. On the other hand, the oxy group of 3,4'-ODA has low polarity relative to the carbonyl group and is an electron-pushing group, so its diamine reactivity is high, which is beneficial to polymerize into polymers.

Formula (c-1), Formula (c-2).

式(d-1)、 式(d-2)。 However, in order to meet better low dielectric loss and lower thermal expansion coefficient, the present invention adopts 3,4'-ODA, which contains the structure shown in formula (c-1), to achieve a locally linear structure and have a low Properties of dielectric loss. To further reduce the dielectric loss, a linear structure must be introduced, so the present invention introduces the diamine structure shown in formula (d-1) or formula (d-2).

Formula (d-1), Formula (d-2).

In detail, the diamine structure represented by formula (d-1) is 2,2'-dimethyl-p-benzidine (m-Tolidine), while the diamine structure represented by formula (d-2) is 2,2' - Bis(trifluoromethyl)-diaminobiphenyl (2,2'-bis(trifluoromethyl)benzidine, TFMB). In addition, to meet the requirement of low thermal expansion coefficient, it is necessary to introduce a diamine structure as shown in formula (a-1), which can be p-phenylenediamine (Phenylene diamine, PDA) to increase the rigidity of polyimide .

In this way, the polymerization of 3,4'-ODA, PDA, m-Tolidine, TFMB or their mixed diamine monomers and dianhydride monomers in the present invention should conform to the polyimide with a better linear arrangement structure.

＜Polyimide film＞

式(I-A)。 此時，所製備之聚醯亞胺膜的熱膨脹係數可為9 ppm/ ^oC至33 ppm/ ^oC，介電常數可為2.8至3.3，且介電損失可為0.0017至0.0038。 The polyimide film of the present invention comprises the aforementioned polyimide, in detail, when in the polyimide of formula (I), R is hydrogen and x+z is 1 (i.e. y, q are 0 ), which has a structure as shown in formula (IA):

Formula (IA). At this time, the thermal expansion coefficient of the prepared polyimide film can be 9 ppm/ ^° C to 33 ppm/ ^° C, the dielectric constant can be 2.8 to 3.3, and the dielectric loss can be 0.0017 to 0.0038.

式(I-B)。 當Q為甲基時，所製備之聚醯亞胺膜的介電損失可為小於0.0025。另外，當Q為三氟甲基時，所製備之聚醯亞胺膜的介電損失可為0.0017至0.0028，且導入三氟甲基之含氟結構可以有助於提高疏水性以及增加自由體積，進而有效降低介電常數。 In addition, when in the polyimide of formula (I), R is hydrogen and x+y is 1 (that is, z, q are 0), it has a structure as shown in formula (IB):

Formula (IB). When Q is a methyl group, the dielectric loss of the prepared polyimide film can be less than 0.0025. In addition, when Q is trifluoromethyl, the dielectric loss of the prepared polyimide film can be 0.0017 to 0.0028, and the fluorine-containing structure introduced into trifluoromethyl can help to improve hydrophobicity and increase free volume , thereby effectively reducing the dielectric constant.

式(I-C)。 Yet, when in the polyimide of formula (I), R is hydrogen and x+q is 1 (that is y, z are 0), then has a structure as shown in formula (IC):

Formula (IC).

＜Flexible copper foil substrate＞

The present invention provides a flexible copper foil substrate with low dielectric loss and high dimensional stability, which includes a copper foil and the aforementioned polyimide film, wherein the polyimide film is bonded to the copper foil, and the copper foil is a basic Any copper foil used in flexible copper foil substrates known in the art will not be described in detail here. In this way, because the polyimide film has low dielectric constant and low dielectric loss, the prepared flexible copper foil substrate has low dielectric loss, and when the flexible copper foil substrate is applied in a flexible circuit board, its circuit The electrical interference between them is reduced, helping to avoid power loading and signal delays. In addition, because polyimide has a thermal expansion coefficient similar to that of copper foil, the prepared flexible copper foil substrate has high dimensional stability, and the substrate will not warp due to the large difference in thermal expansion coefficient in the subsequent heating process. crack phenomenon.

<Manufacturing method of flexible copper foil substrate with low dielectric loss and high dimensional stability>

Please refer to FIG. 2 , which is a flowchart illustrating a method 100 for manufacturing a flexible copper foil substrate with low dielectric loss and high dimensional stability according to an embodiment of the present invention. In FIG. 2 , the manufacturing method 100 of the flexible copper foil substrate with low dielectric loss and high dimensional stability includes step 110 and step 120 .

式(i)、 式(ii-1)、 式(ii-2)、 式(ii-3)、

式(ii-4)、 式(iii)， 其中，R為氫、碳數1至6的烷基、三氟甲基、苯基或鹵素基。 Step 110 is to carry out a mixing step, which is a diamine monomer shown in formula (i) and a formula (ii-1), such as formula (ii-2), such as formula (ii-3) or After dissolving the diamine monomer shown in formula (ii-4) in an organic solvent, add a dianhydride monomer shown in formula (iii) and mix to form a polyamic acid solution:

Formula (i), Formula (ii-1), Formula (ii-2), Formula (ii-3),

Formula (ii-4), Formula (iii), Wherein, R is hydrogen, alkyl having 1 to 6 carbons, trifluoromethyl, phenyl or halogen.

Step 120 is to carry out a condensation reaction, which is to apply the polyamic acid solution on the copper foil, and heat and close the loop to obtain a flexible copper foil substrate with low dielectric loss and high dimensional stability.

In detail, the organic solvent used in the mixing step can be but not limited to dimethylacetamide (dimethylacetamide, DMAc), dimethylformamide (dimethylformamide, DMF) or N-methylpyrrolidone (N-methyl -2-pyrrolidone, NMP), and in this step, the aforementioned diamine monomer shown in formula (i) plus formula (ii-1), formula (ii-2), formula (ii- 3) or the molar ratio of the diamine monomer represented by formula (ii-4) to the dianhydride monomer represented by formula (iii) may be 0.9 to 1.1. Then in the condensation reaction, the polyamic acid solution is coated on the copper foil and heated to remove the solvent, and then a polyimide film comprising the polyimide shown in formula (I) can be synthesized, and obtained A flexible copper foil substrate formed by joining copper foil and polyimide film, the coating method can be but not limited to doctor blade coating method or spin coating method.

＜Electronic devices＞

The present invention provides an electronic device, which comprises the aforementioned flexible copper foil substrate with low dielectric loss and high dimensional stability. For the flexible copper foil substrate with low dielectric loss and high dimensional stability, please refer to the above, and will not be repeated here. The structure and manufacturing method of the electronic device are conventional, and will not be repeated here.

The following specific examples are hereby further illustrated to illustrate the present invention, so that those who are ordinary in the technical field to which the present invention belongs can fully utilize and practice the present invention without excessive interpretation, and these examples should not be regarded as To limit the scope of the invention, but to illustrate how to practice the materials and methods of the invention.

<Example/Comparative Example>

Embodiment 1: First get 1.0 grams (4.994 millimoles) of 3,4'-ODA diamine monomers and 0.1800 grams (1.665 millimoles) of PDA diamine monomers, dissolve them in 25 grams of dewatered NMP ( 20 wt%), after the diamine monomer is completely dissolved, add 3.0519 g (6.659 mmol) of p-phenylene-bis (trimellitate) dianhydride (p-Phenylene bis(trimellitate) dianhydride, TAHQ) , stirred for 24 hours under a nitrogen atmosphere, then controlled the thickness of the scraper to 400 μm and coated it on the copper foil substrate, placed it in a circulating oven and heated it at 150 ^o C for 20 minutes, dried most of the solvent, and then raised the temperature by 150 ^{o C} in stages Half an hour at C, 1 hour at 200 ^o C, one hour at 250 ^o C, and one hour at 300 ^o C, the single-sided copper foil flexible board of Example 1 can be used for the heat resistance test of tin bleaching, and then the copper foil substrate can be etched Obtain the polyimide film power supply test of embodiment 1. The reaction equation of Example 1 is shown in Table 2 below. Table II

Embodiment 2: First get 1.0 grams (4.994 millimoles) of 3,4'-ODA diamine monomers and 0.5401 grams (4.994 millimoles) of PDA diamine monomers, dissolve them in 25 grams of dewatered NMP ( 20 wt%), after the diamine monomer is completely dissolved, add the TAHQ dianhydride monomer of 4.5778 grams (9.988 millimoles), and stir for 24 hours under a nitrogen environment, and the subsequent steps are the same as in Example 1, and can be implemented The single-sided copper-clad flexible board of Example 2 was used for the heat resistance test of tin-bleaching. Then, the copper-clad substrate was etched to obtain the polyimide film of Example 2 for the power supply test. The reaction equation of Example 2 is shown in Table 3 below. Table three

Embodiment 3: First get 1.0 grams (4.994 millimoles) of 3,4'-ODA diamine monomers and 1.6202 grams (14.98 millimoles) of PDA diamine monomers, dissolve them in 25 grams of dewatered NMP ( 20 wt%), after the diamine monomer is completely dissolved, add the TAHQ dianhydride monomer of 9.1556 grams (19.98 millimoles), and stir for 24 hours under a nitrogen environment, and the subsequent steps are the same as in Example 1, and can be implemented The single-sided copper foil flexible board of Example 3 was used for the heat resistance test of tin-flooding, and then, the copper foil substrate was etched to obtain the power supply test of the polyimide film of Example 3. The reaction equation of Example 3 is shown in Table 4 below. Table four

Example 4: First take 1.0 g (4.994 mmol) of 3,4'-ODA diamine monomer and 0.3534 g (1.665 mmol) of m-Tolidine diamine monomer, dissolve them in 25 g of dewatered NMP In (20 wt%), after the diamine monomer is completely dissolved, add the TAHQ dianhydride monomer of 9.1556 grams (19.98 mmoles), and stir for 24 hours under a nitrogen environment, and the subsequent steps are the same as in Example 1. The single-sided copper foil flexible board of Example 4 was obtained for the tin-flooding heat resistance test, and then the copper foil substrate was etched to obtain the polyimide film power supply test of Example 4. The reaction equation of Example 4 is shown in Table 5 below. Table five

Example 5: First take 1.0 g (4.994 mmol) of 3,4'-ODA diamine monomer and 1.0602 g (4.994 mmol) of m-Tolidine diamine monomer, dissolve them in 25 g of dehydrated NMP In (20 wt%), after the diamine monomer is completely dissolved, add the TAHQ dianhydride monomer of 4.5778 grams (9.988 mmoles), and stir for 24 hours under a nitrogen environment, and the subsequent steps are the same as in Example 1. The single-sided copper foil flexible board of Example 5 was obtained for the heat resistance test of tin bleaching. Then, the copper foil substrate was etched to obtain the power supply test of the polyimide film of Example 5. The reaction equation of Example 5 is shown in Table 6 below. Table six

Example 6: First take 1.0 g (4.994 mmol) of 3,4'-ODA diamine monomer and 3.1805 g (14.98 mmol) of m-Tolidine diamine monomer, dissolve them in 25 g of dehydrated NMP In (20 wt%), after the diamine monomer is completely dissolved, add the TAHQ dianhydride monomer of 9.1556 grams (19.98 mmoles), and stir for 24 hours under a nitrogen environment, and the subsequent steps are the same as in Example 1. The single-sided copper foil flexible board of Example 6 was obtained for the heat resistance test of tin bleaching, and then the copper foil substrate was etched to obtain the power supply test of the polyimide film of Example 6. The reaction equation of Example 6 is shown in Table 7 below. Table seven

Example 7: First take 1.0 g (4.994 mmol) of 3,4'-ODA diamine monomer and 0.5331 g (1.665 mmol) of TFMB diamine monomer, and dissolve them in 25 g of dewatered NMP ( 20 wt%), after the diamine monomer is completely dissolved, add the TAHQ dianhydride monomer of 3.0519 grams (6.6587 millimoles), and stir for 24 hours under a nitrogen environment, and the subsequent steps are the same as in Example 1, and can be implemented The single-sided copper-clad flexible board of Example 7 was used for the heat resistance test of tin-bleaching, and then, the copper-clad substrate was etched to obtain the polyimide film of Example 7 for the power supply test. The reaction equation of Example 7 is shown in Table 8 below. table eight

Example 8: First take 1.0 g (4.994 mmol) of 3,4'-ODA diamine monomer and 1.5992 g (4.994 mmol) of TFMB diamine monomer, and dissolve them in 25 g of dewatered NMP ( 20 wt%), after the diamine monomer is completely dissolved, add the TAHQ dianhydride monomer of 4.5778 grams (9.988 millimoles), and stir for 24 hours under a nitrogen environment, and the subsequent steps are the same as in Example 1, and can be implemented The single-sided copper foil flexible board of Example 8 was used for the heat resistance test of tin-floating, and then, the copper foil substrate was etched to obtain the power supply test of the polyimide film of Example 8. The reaction equation of Example 8 is shown in Table 9 below. Table nine

Example 9: First take 1.0 g (4.994 mmol) of 3,4'-ODA diamine monomer and 4.7977 g (14.98 mmol) of TFMB diamine monomer, and dissolve them in 25 g of dewatered NMP ( 20 wt%), after the diamine monomer is completely dissolved, add the TAHQ dianhydride monomer of 9.1556 grams (19.98 millimoles), and stir for 24 hours under a nitrogen environment, and the subsequent steps are the same as in Example 1, and can be implemented The single-sided copper foil flexible board of Example 9 was used for the heat resistance test of tin-flooding, and then, the copper foil substrate was etched to obtain the power supply test of the polyimide film of Example 9. The reaction equation of Example 9 is shown in Table 10 below. table ten

Example 10: First take 1.0 g (4.994 mmol) of 3,4'-ODA diamine monomer and 0.1901 g (1.665 mmol) of CHDA diamine monomer, and dissolve them in 25 g of dehydrated NMP ( 20 wt%), after the diamine monomer is completely dissolved, add the TAHQ dianhydride monomer of 3.0519 grams (6.659 millimoles), and stir for 24 hours under a nitrogen environment, and the subsequent steps are the same as in Example 1, and can be implemented The single-sided copper foil flexible board of Example 10 was used for the heat resistance test of tin-floating, and then, the copper foil substrate was etched to obtain the power supply test of the polyimide film of Example 10. The reaction equation of Example 10 is shown in Table 11 below. Table Eleven

Comparative Example 1: First take 2.0 grams (4.994 millimoles) of 3,4'-ODA diamine monomer and dissolve it in 25 grams of dehydrated NMP (20 wt%). After the diamine monomer is completely dissolved, add 4.5778 The TAHQ diacid anhydride monomer of gram (9.988 millimoles) was stirred for 24 hours under a nitrogen atmosphere, and the subsequent steps were the same as in Example 1, so that the single-sided copper foil soft board of Comparative Example 1 could be used for the tin-flooding heat resistance test. Next, the polyimide film of Comparative Example 1 was obtained by etching the copper foil substrate for power supply test. The reaction equation of Comparative Example 1 is shown in Table 12 below. Table 12

Comparative example 2: first get the PDA diamine monomer of 1.0 gram (9.247 mmol) and be dissolved in the dewatering NMP of 25 grams (20 wt%), after treating that diamine monomer dissolves completely, add 4.2383 grams (9.247 mmol ear) TAHQ diacid anhydride monomer, stirred for 24 hours under a nitrogen atmosphere, and the subsequent steps were the same as in Example 1, and the single-sided copper foil soft board of Comparative Example 2 could be obtained for the heat resistance test of tin bleaching. Then, the copper foil The polyimide film of Comparative Example 2 can be obtained by etching the substrate for power supply test. The reaction equation of Comparative Example 2 is shown in Table 13 below. Table 13

Comparative Example 3: First get 2.0 grams (9.421 millimoles) of m-Tolidine diamine monomer and dissolve it in 25 grams of dewatered NMP (20 wt%). After the diamine monomer is completely dissolved, add 4.3180 grams (9.421 millimole) of TAHQ dianhydride monomer, stirred for 24 hours under nitrogen atmosphere, and the subsequent steps were the same as in Example 1, and the single-sided copper foil flexible board of Comparative Example 3 could be obtained for the tin-flooding heat resistance test. Then, the The polyimide film of Comparative Example 3 can be obtained by etching the copper foil substrate for the power supply test. The reaction equation of Comparative Example 3 is shown in Table 14 below. Table Fourteen

Comparative example 4: get the TFMB diamine monomer of 2.0 grams (6.246 millimolar) earlier and be dissolved in the dehydration NMP of 25 grams (20 wt%), after treating that diamine monomer dissolves completely, add 2.8625 grams (6.246 millimolar) ear) TAHQ diacid anhydride monomer, stirred for 24 hours under a nitrogen atmosphere, and the subsequent steps were the same as in Example 1, and the single-sided copper foil soft board of Comparative Example 4 could be obtained for the heat resistance test of tin bleaching. Then, the copper foil The polyimide film of Comparative Example 4 can be obtained by etching the substrate for power supply test. The reaction equation of Comparative Example 4 is shown in Table 15 below. Table 15

Comparative Example 5: First take 1.0 g (4.994 mmol) of 3,4'-ODA diamine monomer and 1.0602 g (4.994 mmol) of m-Tolidine diamine monomer, dissolve them in 25 g of dehydrated NMP In (20 wt%), after the diamine monomer is completely dissolved, add the TABP dianhydride monomer of 5.3379 grams (9.988 mmoles), and stir for 24 hours under a nitrogen environment, and the subsequent steps are the same as in Example 1. The single-sided copper foil flexible board of Comparative Example 5 was obtained for the heat resistance test of tin bleaching, and then the copper foil substrate was etched to obtain the power supply test of the polyimide film of Comparative Example 5. The reaction equation of Comparative Example 5 is shown in Table 16 below. Table 16

Comparative Example 6: First take 1.0 g (4.994 mmol) of 3,4'-ODA diamine monomer and 1.0602 g (4.994 mmol) of m-Tolidine diamine monomer, dissolve them in 25 g of dehydrated NMP In (20 wt%), after the diamine monomer dissolves completely, add the PMDA dianhydride monomer of 2.1786 grams (9.98 millimoles), stir 24 hours under nitrogen environment, after the step is identical with embodiment 1, can The single-sided copper foil flexible board of Comparative Example 6 was obtained for the heat resistance test of tin bleaching. Then, the copper foil substrate was etched to obtain the power supply test of the polyimide film of Comparative Example 6. The reaction equation of Comparative Example 6 is shown in Table 17 below. Table 17

Comparative Example 7: First take 1.0 g (4.994 mmol) of 3,4'-ODA diamine monomer and 1.0602 g (4.994 mmol) of m-Tolidine diamine monomer, dissolve them in 25 g of dehydrated NMP In (20 wt%), after the diamine monomer is completely dissolved, add the BPDA dianhydride monomer of 2.9387 grams (9.988 millimoles), and stir for 24 hours under a nitrogen environment, and the subsequent steps are the same as in Example 1. The single-sided copper foil flexible board of Comparative Example 7 was obtained for the heat resistance test of tin-flooding, and then the copper foil substrate was etched to obtain the polyimide film of Comparative Example 7 for the power supply test. The reaction equation of Comparative Example 7 is shown in Table 18 below. Table 18

Comparative Example 8: First get 1.0 g (8.757 mmol) of CHDA diamine monomer and dissolve it in 25 g of dewatered NMP (20 wt%). After the diamine monomer is completely dissolved, add 4.0137 g (8.757 mmol) ear) TAHQ diacid anhydride monomer, stirred for 24 hours under a nitrogen environment, and the subsequent steps were the same as in Example 1, and the single-sided copper foil soft board of Comparative Example 8 could be used for the tin-floating heat resistance test. Then, the copper foil The polyimide film of Comparative Example 8 can be obtained by etching the substrate for power supply test. The reaction equation of Comparative Example 8 is shown in Table 19 below. Table nineteen

＜Evaluation test method＞

Tin-flooding heat resistance test: Place the prepared single-sided copper foil soft board at 288 ^o C for 10 seconds, and test for three times to visually check for blisters.

13 cm，於室溫下測量。 Dielectric analysis method: first dry the prepared polyimide film at 120 ^o C to remove water for 1 hour, then place it in a 10 GHz dielectric constant meter for dielectric analysis, and take the average value of three tests. Among them, the brand and model of the dielectric constant meter (Dielectric constant Analysis) are Taiwan Rohde Schwartz/Steel/ZNB20, and the dielectric constant (D _k ) and dielectric loss (D k ) of the cured film are measured at 10 GHz. _f ), the cured film must be less than or equal to 350 μm, and the film should be cut to 9 cm

13 cm, measured at room temperature.

Example 1 to Example 10 and Comparative Example 1 to Comparative Example 8 were subjected to the above evaluation test method, and the results were recorded in Table 20. Table twenty diamine dianhydride Film forming Tin bleaching heat resistance _{D f} CTE (ppm/ ^oC ) Example 1 3,4'-ODA/PDA = 3/1 TAHQ o pass 2.8 0.0019 33 Example 2 3,4'-ODA/PDA = 1/1 TAHQ o pass 3.2 0.0020 20 Example 3 3,4'-ODA/PDA = 1/3 TAHQ o pass 3.3 0.0027 18 Example 4 3,4'-ODA/ m-Tolidine = 3/1 TAHQ o pass 2.9 0.0014 32 Example 5 3,4'-ODA/ m-Tolidine = 1/1 TAHQ o pass 3.2 0.0014 30 Example 6 3,4'-ODA/ m-Tolidine = 1/3 TAHQ o pass 3.1 0.0011 twenty three Example 7 3,4'-ODA/ TFMB = 3/1 TAHQ o pass 3.0 0.0020 26 Example 8 3,4'-ODA/ TFMB = 1/1 TAHQ o pass 2.9 0.0019 twenty one Example 9 3,4'-ODA/ TFMB = 1/3 TAHQ o pass 2.6 0.0019 twenty three Example 10 3,4'-ODA/ CHDA = 1/1 TAHQ o pass 3.2 0.0019 40 Comparative example 1 3,4'-ODA TAHQ o pass 3.0 0.0017 32 Comparative example 2 PDA TAHQ o pass 3.2 0.0038 9 Comparative example 3 m-Tolidine TAHQ o pass 2.8 0.0017 twenty four Comparative example 4 TFMB TAHQ o pass 3.3 0.0028 twenty three Comparative Example 5 3,4'-ODA/ m-Tolidine = 1/1 TABP o pass 3.0 0.0024 - Comparative example 6 3,4'-ODA/ m-Tolidine = 1/1 PMDA o pass 3.4 0.015 - Comparative Example 7 3,4'-ODA/ m-Tolidine = 1/1 BPDA o pass 3.2 0.0058 - Comparative Example 8 CHDA TAHQ x x - - -

From the results in Table 20 above, it can be seen that the flexible copper foil substrate in this case has low dielectric loss and high dimensional stability, and the details are as follows.

The effect of m-Tolidine on dielectric loss can be compared when the dianhydride structure is fixed. For example, compared with embodiment 4 to embodiment 6, its dielectric loss decreases with the higher content of m-Tolidine added, and the dielectric loss is between 0.0011 to 0.0017, wherein embodiment 6 has the lowest dielectric loss 0.0011. Therefore, it can be found that the copolymerized polyimide formed by mixing 3,4'-ODA and m-Tolidine diamine monomers has lower dielectric loss characteristics, which is related to better linearity after introducing m-Tolidine.

The effect of PDA on the coefficient of thermal expansion can be compared when the dianhydride structure is fixed. For example, compared with Example 1 to Example 3 and Comparative Example 2, its coefficient of thermal expansion decreases with the higher content of PDA added, and the coefficient of thermal expansion is between 9 ppm/ ^° C to 33 ppm/ ^° C, where The coefficient of thermal expansion of Example 3 is 18 ppm/ ^o C, which is closest to that of copper foil (17 ppm/ ^o C). Therefore, it can be found that the copolymerized polyimide formed by mixing 3,4'-ODA and PDA diamine monomers has a thermal expansion coefficient similar to that of copper foil, which is related to the better linearity of PDA and is conducive to the production of multi-layer plates. Therefore, the prepared flexible copper foil substrate has high dimensional stability.

In addition, when the diamine structure is fixed, the effect of different dianhydrides on the dielectric loss can be compared. For example, compared with Example 5, Comparative Example 6, and Comparative Example 7, the dielectric losses are 0.0014, 0.015, and 0.0058, respectively. Therefore, it can be found that TAHQ is superior to BPDA in terms of the structure of dianhydrides, and BPDA is superior to PMDA, so dianhydrides containing ester groups are important raw materials for low dielectric loss.

In summary, the polyimide synthesized by mixing 3,4'-ODA and m-Tolidine diamine monomers and TAHQ dianhydride monomers containing ester groups in the present invention has low dielectric constant and low dielectric loss properties, while the polyimide synthesized by mixing 3,4'-ODA and PDA diamine monomers with TAHQ dianhydride monomers containing ester groups has the characteristics of thermal expansion coefficient and low dielectric loss close to that of copper foil substrates, Moreover, the flexible copper foil substrate prepared by the above-mentioned monomers can pass the heat resistance test of tin bleaching, which is beneficial to the production of flexible printed circuit boards for 5G high-frequency transmission, so as to meet the needs of the industry.

Although the present invention has been disclosed above in terms of implementation, it is not intended to limit the present invention. Anyone skilled in this art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection of the present invention The scope shall be defined by the appended patent application scope.

100: Preparation method of flexible copper foil substrate with low dielectric loss and high dimensional stability 110,120: steps

In order to make the above and other objects, features, advantages and embodiments of the present invention more clearly understood, the accompanying drawings are described as follows: Fig. 1A, Fig. 1B, Fig. 1C, Fig. 1D, Fig. 1E, Fig. 1F and Fig. 1G are diagrams showing the molecular chain arrangement structure; and FIG. 2 is a flow chart showing the steps of a method for preparing a flexible copper foil substrate with low dielectric loss and high dimensional stability according to an embodiment of the present invention.

Claims (9)

A flexible copper foil substrate with low dielectric loss and high dimensional stability, comprising: a copper foil; and a polyimide film bonded to the copper foil, and the polyimide film comprises a polyimide film Amine, this polyimide has one structure as shown in formula (I):

Wherein, A ₁ is a structure shown in formula (I-1), A ₂ is a structure shown in formula (I-2), A ₄ is a structure shown in formula (I-4):

Wherein, R is hydrogen, Q is an alkyl group or trifluoromethyl group with 1 carbon number, x, y, z and q are integers or decimals, n is the degree of polymerization, and 0<x<1, 0

y<1, z=0, 0

q<1, 1

no

500; where x+y is 1 and q is 0; or x+q is 1 and y is 0. The flexible copper foil substrate with low dielectric loss and high dimensional stability as described in claim 1, wherein when R is hydrogen and x+y is 1 in the formula (I), the polyimide film is This polyimide that comprises has a structure as shown in formula (IB):

Wherein Q is methyl or trifluoromethyl. The flexible copper foil substrate with low dielectric loss and high dimensional stability as described in Claim 1, wherein when R is hydrogen and x+q is 1 in the formula (I), the polyimide film is The polyimide that comprises has a structure as shown in formula (IC):

The flexible copper foil substrate with low dielectric loss and high dimensional stability as claimed in Claim 1, wherein the thermal expansion coefficient of the polyimide film is 9 ppm/°C to 33 ppm/°C. The flexible copper foil substrate with low dielectric loss and high dimensional stability as claimed in Claim 1, wherein the dielectric loss of the polyimide film is less than 0.0025. A method for preparing a flexible copper foil substrate with low dielectric loss and high dimensional stability as described in claim 1, comprising: performing a mixing step, which is to mix a diamine monomer as shown in formula (i) And after dissolving the diamine monomer shown in formula (ii-1), formula (ii-3) or formula (ii-4) in an organic solvent, add a diamine monomer shown in formula (iii) Diic anhydride monomers, mixed to form a polyamic acid solution:

Wherein, R is hydrogen; and a condensation reaction is carried out, which is to apply the polyamic acid solution to the copper foil, and heat and close the ring to obtain the soft material with low dielectric loss and high dimensional stability. Copper foil substrate. The method for preparing a flexible copper foil substrate with low dielectric loss and high dimensional stability as described in Claim 6, wherein the organic solvent is dimethylacetamide, dimethylformamide or N-methylpyrrolidone . The method for preparing a flexible copper foil substrate with low dielectric loss and high dimensional stability as described in claim 6, wherein the diamine monomer shown in formula (i) plus the formula (ii-1) , The molar ratio of the diamine monomer represented by formula (ii-3) or formula (ii-4) to the dianhydride monomer represented by formula (iii) is 0.9 to 1.1. An electronic device comprising the flexible copper foil substrate with low dielectric loss and high dimensional stability as described in any one of claim 1 to claim 5.

Images