JP2004158493A - Copper-coated plastic board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper-coated plastic board where a copper layer as well as a seed layer can be patterned through an etching method using a ferric chloride solution or a copper chloride solution, a copper conductor layer having a thickness of 8 μm displays an initial adhesive force of 500 N/m or above, and furthermore the copper conductor layer subjected to 10 seconds thermocompression bonding in a temperature range of 350 to 450°C has also a high-temperature heat-resistant adhesive force of 500N/m or above. <P>SOLUTION: The copper conductor layer is formed on the seed layer for the formation of the copper-coated plastic board. The seed layer is composed of a first seed layer which is formed on a plastic film made of chrome, and has a thickness of 5 to 25 Å; and a second seed layer which is formed on the first seed layer, 10 to 300 Å in thickness made of a nickel chrome alloy having a chrome content of below 15 wt% or 10 to 150 Å in thickness, and made of a nickel chrome alloy having a chrome content in the range between 15 wt% and 40 wt%. <P>COPYRIGHT: (C)2004,JPO

Description

【００４３】
表１から明らかなように、実施例１〜７では、クロム層（第一シード層）の膜厚が５Å以上２５Å以下であり、かつクロム濃度が１５重量％未満であるニッケルクロム合金層（第二シード層）の膜厚が１０Å以上３００Å以下であるとき、また、クロム層（第一シード層）の膜厚が５Å以上２５Å以下であり、かつクロム濃度が１５重量％以上４０重量％以下であるニッケルクロム合金層（第二シード層）の膜厚が１０Å以上１５０Å以下であるとき、リード周辺のエッチング状態はシード層の残留がなく良好で、初期密着力が６００Ｎ／ｍ以上、高温耐熱密着力が５００Ｎ／ｍ以上である銅被覆ポリイミド基板が得られることが分かる。これに対して、比較例１〜６では、シード層の構成、または膜厚がこれらの条件に合わないため、リード周辺のエッチング状態、又は高温耐熱密着力のいずれかに満足すべき結果が得られないことが分かる。
【００４４】
【発明の効果】
以上説明したように、本発明の銅被覆プラスチック基板は、塩化鉄溶液や塩化銅溶液を用いたエッチング法によってパターニング可能で、かつ銅導電体の厚み８μｍにおいて、初期密着力、および、３５０℃から４５０℃の温度範囲で１０秒間の熱圧着後の高温耐熱密着力が、いずれも５００Ｎ／ｍ以上となる高耐熱性の２層メッキ基板であり、その工業的価値は極めて大きい。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a copper-coated plastic substrate, and more particularly, it can be patterned not only to a copper layer but also to a seed layer by an etching method using an iron chloride solution or a copper chloride solution, and has an initial adhesive force and a high-temperature heat-resistant adhesive force. For large copper-coated plastic substrates. Such a copper-coated plastic substrate is used as a flexible substrate for electronic components such as a printed wiring board, a flexible printed wiring board, a TAB tape, and a COF tape.
[0002]
[Prior art]
Copper-coated plastic substrates are frequently used as substrates for electronic components such as printed wiring boards (PWB), flexible printed wiring boards (FPC), tape automatic bonding tapes (TAB), and chip-on-film (COF).
These PWB, FPC, TAB, COF and the like are obtained by processing a metal-coated plastic substrate mainly coated with copper as a metal conductor layer on at least one surface of a plastic film such as polyimide. Such a metal-coated plastic substrate includes a three-layer substrate in which a plastic film and a metal foil such as a copper foil are bonded via an adhesive, and a two-layer substrate in which a metal layer is directly formed on the plastic film.
[0003]
The most commonly used two-layer copper-polyimide substrates include a substrate made by casting a polyimide film on a commercially available copper foil, and a dry plating method such as a sputtering method, a vacuum evaporation method, and an ion plating method on a commercially available polyimide film. A substrate is formed by a dry plating method, a wet plating method (electroplating or electroless plating), or a plating method of forming a copper layer by using these together (hereinafter referred to as a two-layer plating substrate). is there.
[0004]
Conventionally, the adhesion between the plastic film and the copper layer in a two-layer plated substrate has been reduced by a post-process of manufacturing PWB, FPC, etc., for example, by laminating and etching metal by electroplating in a circuit forming process. There was a problem of lowering.
As a solution to this, a method of forming a seed metal layer having better adhesion than copper between a plastic and a copper layer has been proposed. Representative metal types and film formation methods for the seed layer include the following. Such a thing is mentioned.
(1) Nickel or a nickel alloy is formed by an ion plating method (see Patent Document 1).
(2) Nickel, cobalt, zirconium, palladium or an alloy containing them is formed by an ion plating method (see Patent Document 2).
(3) One of nickel, cobalt, zirconium and palladium is formed by a physical vapor deposition method (see Patent Document 3).
(4) Nickel, tin, manganese, and indium are formed by an evaporation method (see Patent Document 4).
(5) forming a 50-500 angstroms deposited metal chromium layer (see Patent Document 5);
(6) Nickel or nickel-chromium is formed by a vapor deposition method (see Patent Document 6).
(7) A chromium layer of 0.01 to 5 μm is formed by a sputtering method (see Patent Document 7).
[0005]
However, these proposals have been effective in improving the adhesion (initial adhesion) after forming a circuit in the adhesion between a plastic film such as polyimide and a copper layer, but the adhesion after a thermal load at a high temperature has been effective. It does not meet the demand for force (high temperature heat resistance).
In recent years, in particular, as portable electronic devices have become smaller and thinner, the above-mentioned TAB and COF have also been required to be smaller and thinner, that is, have higher densities, and their wiring pitch (wiring width / space width) has become increasingly narrower. Therefore, a two-layer plated substrate in which the thickness of a conductor layer (copper film) is thin and which can be freely controlled has attracted particular attention. At the same time, the required performance for heat resistance is increasing.
[0006]
Then, a solution aiming at improvement of heat resistance has been proposed, and as a representative method, for example, the following method can be mentioned.
(1) A chromium / chromium oxide layer having a thickness of 25 to 150 ° is formed by a sputtering method (see Patent Document 8).
(2) Even if heated at 150 ° C. for 4 hours, a cobalt layer is formed by a sputtering method to such a thickness that a decrease in the adhesive strength between the metal layer and the polyimide layer can be suppressed within 5% (see Patent Document 9). ,
(3) A titanium layer is formed by a sputtering method to such a thickness that a decrease in the adhesive strength between the metal layer and the polyimide layer can be suppressed to within 5% even when heated at 150 ° C. for 4 hours (see Patent Document 10).
(4) A molybdenum layer is formed by a sputtering method to such a thickness that a decrease in the adhesive strength between the metal layer and the polyimide layer can be suppressed to within 5% even when heated at 150 ° C. for 4 hours (see Patent Document 11). ,
(5) An alloy layer containing at least two or more of titanium, cobalt, molybdenum, and nickel is formed by a sputtering method (see Patent Document 12).
(6) A nichrome alloy having a thickness of 50 to 500 angstroms is formed by a sputtering method (see Patent Document 13).
(7) At least one selected from the group consisting of nickel, copper-nickel alloy, chromium, and chromium oxide is formed by a dry plating method such as a sputtering method, a vacuum evaporation method, and an ion plating method (Patent Document 14). reference).
[0007]
These proposals have contributed to the improvement of the heat resistance in each application, but are also required to respond to severer high-temperature heat resistance and film characteristics that are easily etched. For example, a method has been proposed in which a chromium / chromium oxide sputtering layer having a thickness of 25 to 150 ° is formed on an electrically insulating support film such as polyimide and a copper layer is further formed (see Patent Document 8). In the case of such a two-layer plating substrate having a chromium / chromium oxide seed layer of 25 ° or more, in the patterning process, after the copper layer is etched with an iron chloride solution or a copper chloride solution, the remaining chromium seed layer is removed. In addition, it is necessary to use chemicals that have a burden on the environment, such as potassium permanganate solution.
[0008]
However, in response to recent social demands for environmental conservation, COF processing does not use potassium permanganate solution, but uses a more environmentally friendly iron chloride solution or copper chloride solution. There is a need for a two-layer plating substrate that can etch down to a layer.
Further, in the COF processing step, Sn plating is performed on the Cu leads of the two-layer plated substrate after the patterning. The Sn-plated Cu lead is electrically and mechanically connected to the Au bump on the Si chip. This connection is called an ILB (Inner Lead Bonding) connection, and in this case, the two-layer plated substrate is exposed to a high temperature of 200 ° C. or more, and in some cases, 350 ° C. to 450 ° C.
[0009]
However, the conventional two-layer plated substrate has a problem that the adhesion after a high-temperature heat load due to the ILB connection is significantly reduced. For example, the high-temperature heat-resistant adhesion after a two-layer plated substrate having an initial adhesion of 500 N / m or more and thermocompression bonding at a temperature in the range of 350 ° C. to 450 ° C. for 10 seconds is reduced to 500 N / m or less. .
From the above situation, the market demands a two-layer plated substrate that can be etched with an iron chloride solution or a copper chloride solution and that has high reliability in adhesion between a copper layer and a plastic film after a high-temperature heat load. .
[0010]
[Patent Document 1]
JP-B-57-18356 (page 1)
[Patent Document 2]
JP-B-57-18357 (page 1)
[Patent Document 3]
Japanese Patent Publication No. 57-33718 (page 1)
[Patent Document 4]
JP-A-61-128593 (page 2)
[Patent Document 5]
JP-A-62-62551 (page 1)
[Patent Document 6]
JP-A-62-181488 (page 1)
[Patent Document 7]
JP-A-02-98994 (page 1)
[Patent Document 8]
Japanese Patent Publication No. 04-65558 (page 1)
[Patent Document 9]
Japanese Patent Application Laid-Open No. 08-330693 (page 2)
[Patent Document 10]
JP-A-08-330694 (page 2)
[Patent Document 11]
Japanese Patent Application Laid-Open No. 08-330695 (page 2)
[Patent Document 12]
JP-A-08-332697 (page 2)
[Patent Document 13]
JP-A-09-83134 (page 2)
[Patent Document 14]
JP-A-10-256700 (page 2)
[0011]
[Problems to be solved by the invention]
In view of the above problems of the prior art, an object of the present invention is to pattern not only a copper layer but also a seed layer by an etching method using an iron chloride solution or a copper chloride solution, and at a thickness of 8 μm of the copper conductor layer, An object of the present invention is to provide a copper-coated plastic substrate having an initial adhesive force and a high-temperature heat-resistant adhesive force after thermocompression bonding in a temperature range of 350 ° C. to 450 ° C. for 10 seconds, each of which is 500 N / m or more.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the inventors have conducted intensive studies on the configuration of a seed layer formed between a plastic film and a copper layer on a copper-coated plastic substrate, and as a result, optimized the configuration of the seed layer. That is, the seed layer has a two-layer structure including a chromium layer and a nickel-chromium alloy layer, and the thickness of these seed layers is appropriately controlled while keeping the chromium concentration in the nickel-chromium alloy in a specific range. They have found that they can be solved and completed the present invention.
[0013]
That is, according to the first invention of the present invention, a copper-coated plastic formed by forming a seed layer directly on both sides or one side of a plastic film without using an adhesive and forming a copper conductor layer on the seed layer In the substrate, the seed layer includes a first seed layer formed of a chromium layer having a thickness of 5 to 25 mm formed on a plastic film, and a nickel chromium layer having a thickness of 10 to 300 mm formed on the first seed layer. A second seed layer comprising a nickel-chromium alloy layer having a chromium concentration in the alloy of less than 15% by weight or a film thickness of 10 to 150% and a chromium concentration in the nickel-chromium alloy of 15 to 40% by weight; And a copper-coated plastic substrate characterized by comprising:
[0014]
According to a second aspect of the present invention, there is provided the copper-coated plastic substrate according to the first aspect, wherein the first seed layer and the second seed layer are formed by a sputtering method.
[0015]
According to a third aspect of the present invention, there is provided the copper-coated plastic substrate according to the first or second aspect, wherein the plastic film is a polyimide film.
[0016]
Further, according to the fourth invention of the present invention, in any one of the first to third inventions, the high-temperature heat-resistant adhesive strength after hot-press bonding in a temperature range of 350 to 450 ° C. for 10 seconds at a thickness of the copper conductor layer of 8 μm. There is provided a copper-coated plastic substrate characterized by being at least 500 N / m.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the copper-coated plastic substrate of the present invention will be described in detail.
[0018]
The copper-coated plastic substrate according to the present invention has environmentally friendly etching processability and excellent high-temperature heat resistance. Specifically, it can be patterned by an etching method using an iron chloride solution or a copper chloride solution, and when the thickness of the copper conductor layer is 8 μm, the initial adhesion and the thermocompression bonding at a temperature range of 350 ° C. to 450 ° C. for 10 seconds. The subsequent high-temperature heat-resistant adhesion is 500 N / m or more.
[0019]
The plastic film used in the present invention is not particularly limited, and for example, a film having heat resistance such as polyethylene terephthalate, polyether ketone, polyether imide, polyphenylene sulfide, polyarylate, polyamide, and polyimide is used. Among them, a polyimide film which is particularly excellent in heat resistance and which is comparable to other plastic materials in mechanical, electrical and chemical properties is preferable. The polyimide film used in the present invention may be a commercially available polyimide film having a trade name such as Kapton, Apical, or Upilex, and the thickness is preferably 5 to 75 μm.
[0020]
In the present invention, a seed layer is formed directly on both sides or one side of a plastic film without using an adhesive, and a copper conductor layer is formed on the seed layer. This seed layer is composed of a first seed layer formed on a plastic film and a second seed layer formed on the first seed layer. Two different metal (alloy) layers can be formed. Required. By forming the seed layer with this configuration, the object of the present invention relating to adhesion is achieved.
[0021]
Chromium is used as the first seed layer, and its thickness is 5 ° or more and 25 ° or less, preferably 10 ° to 20 °. If the thickness of the chromium layer is less than 5 °, it is impossible to maintain the desired high-temperature heat resistance, and if it exceeds 25 °, the efficiency of the etching process in the patterning step is reduced or the etching remains.
[0022]
As the second seed layer, a nickel-chromium alloy is used, and its thickness varies depending on the chromium concentration in the nickel-chromium alloy. The chromium concentration in the nickel chromium alloy used as the second seed is 40% by weight or less. If the content exceeds 40% by weight, the efficiency of the etching process in the patterning step is reduced, or the etching remains.
When the chromium concentration is less than 15% by weight, the film thickness is 10 to 300 °, preferably 30 to 200 °. If the thickness of the nickel-chromium alloy is less than 10 °, it is impossible to maintain the desired high-temperature heat resistance, and if it exceeds 300 °, the efficiency of the etching process in the patterning step is reduced, or the etching remains.
When the chromium concentration is 15% by weight or more and 40% by weight or less, the film thickness is 10 ° or more and 150 ° or less, preferably 15 to 100 °. If the thickness of the nickel-chromium alloy is less than 10 °, it is impossible to maintain the desired high-temperature heat resistance, and if it exceeds 150 °, the efficiency of the etching process in the patterning step is reduced.
[0023]
The impurity concentration of chromium as the first seed layer is preferably 2% by weight or less, and the impurity concentration of the nickel chromium alloy as the second seed layer is preferably 1% by weight or less. If the impurity concentration of chromium as the first seed layer exceeds 2% by weight and / or the impurity concentration of the nickel chromium alloy as the second seed layer exceeds 1% by weight, the etching process in the patterning step becomes difficult. This is because the adhesion may vary or the adhesion may vary.
[0024]
The seed layer is preferably formed directly on the surface of the plastic film by a dry plating method such as a sputtering method, a vacuum evaporation method, and an ion plating method. In particular, the sputtering method is preferable from the viewpoint of the adhesion to the plastic film and the stability of controlling the film thickness. In the sputtering method, there is no specific condition, and direct current sputtering, high frequency sputtering, ion beam sputtering, magnetron sputtering or the like is used.
[0025]
Prior to the formation of the seed layer, a chemical treatment with an acid, an alkali, an organic solvent, or the like, or a plasma treatment in a vacuum or air atmosphere may be performed as a modification treatment of the plastic film surface. Further, a heating step may be included as a drying treatment.
[0026]
The copper-coated plastic substrate of the present invention is obtained by forming a copper layer on the second seed layer by a dry plating process such as a sputtering method, a vacuum deposition method, or an ion plating method, or an electrolytic copper plating method or an electroless copper plating. It is formed by a wet plating process such as a method. The copper layer may be formed by combining the dry process and the wet process. For example, on the second seed layer, a copper layer having a thickness of 200 to 5,000 mm is formed by a dry plating process in order to reduce pinhole defects and secure electrical conductivity, and then, mainly to form a conductive and mechanical layer. A copper layer is formed by a wet plating process to a predetermined thickness in order to ensure a proper performance.
The thickness of the copper layer is not particularly limited since an optimum thickness may be selected according to the application, but is preferably 800 ° or more and 35 μm or less. If it is less than 800 °, the conductivity and mechanical strength will be reduced, and if it is more than 35 μm, it will hinder narrowing of the wiring pitch and the productivity will be reduced.
[0027]
The copper-coated plastic substrate of the present invention has two types of first seed layer and second seed layer of different metals as seed layers, and thus has excellent high-temperature heat-resistant adhesion. That is, heat resistance at a high temperature of 350 to 450 ° C. is imparted, and the initial adhesive force and the high temperature heat resistant adhesive force after heat compression bonding for 10 seconds in the temperature range of 350 to 450 ° C. are all 8 μm in thickness of the copper conductor. Is 500 N / m or more, preferably 530 N / m or more.
As described above, the chromium concentration and film thickness in the nickel-chromium alloy layer used for the second seed layer are appropriately formed, the type of plastic film used, the brand name of the film, such as brand, and the surface modification status as a pretreatment In consideration of the above, a copper-coated plastic substrate having higher temperature and heat resistance adhesion can be obtained.
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples of the present invention. However, the present invention is not limited to these Examples. The polyimide films used in the examples and comparative examples, and the sample preparation methods and evaluation methods are as follows.
(1) Polyimide film used Kapton EN manufactured by Toray Dupont Co., Ltd. was used after heating and drying a 38 μm-thick polyimide film in a vacuum.
(2) Sample preparation method and evaluation method A test piece was taken out from the manufactured copper-coated polyimide substrate, and first subjected to patterning. A lead having a width of 1 mm was formed using an iron chloride solution as an etching solution to prepare a sample for measuring adhesion. After patterning, it was confirmed by elemental analysis using an EPMA (Electron Beam Microanalyzer) whether or not portions around the leads of the sample for adhesion measurement where the metal layer was originally to be removed and the polyimide was to be exposed were properly etched. . The sample for adhesion measurement was measured by a 90 degree peel test. This adhesion was defined as the initial adhesion.
Next, another sample for adhesion measurement manufactured in the same manner was heat-pressed at a pressure of 3 MPa for 10 seconds from the polyimide side with a ceramics head heated to 400 ° C. in the air to apply a heat load. The adhesive force after heat-pressing at 400 ° C. was defined as the high-temperature heat-resistant adhesive force.
In addition, since the above-mentioned each adhesive force tends to show a higher value as the copper thickness becomes thicker, the measurement of the adhesive force in the present invention was carried out based on the measurement at a copper thickness of 8 μm which is currently widely used. All of the measurements of the adhesion were performed according to JPCA BM01-11.5.3.
[0029]
Example 1
On one side of the polyimide film, a chromium layer was formed as a first seed layer to a thickness of 8 ° by a sputtering method. Next, a nickel-chromium alloy layer having a chromium concentration of 7% by weight was formed on the first seed layer to a thickness of 100 ° by a sputtering method. Subsequently, a copper layer was first formed to a thickness of 1500 ° by a sputtering method, and then a copper layer was formed to a total thickness of 8 μm by an electrolytic copper plating method to produce a copper-coated polyimide substrate. A sample for evaluation was prepared from a part of the substrate, and the etching state around the lead, the initial adhesion, and the high-temperature heat-resistant adhesion were measured. Table 1 shows the results.
[0030]
Example 2
A copper-coated polyimide substrate was manufactured under the same conditions as in Example 1 except that a chromium layer was formed to a thickness of 20 ° as a first seed layer. Table 1 shows the etching state around the lead, and the measurement results of the initial adhesion and the high-temperature heat-resistant adhesion.
[0031]
Example 3
A copper-coated polyimide substrate was manufactured under the same conditions as in Example 1 except that a chromium layer was formed to a thickness of 15 ° as a first seed layer. Table 1 shows the etching state around the lead, and the measurement results of the initial adhesion and the high-temperature heat-resistant adhesion.
[0032]
Example 4
The same as Example 1 except that a chromium layer was formed to a thickness of 15 ° as a first seed layer, and a nickel-chromium alloy layer having a chromium concentration of 7% by weight was formed to a thickness of 250 ° as a second seed layer. Under the conditions, a copper-coated polyimide substrate was manufactured. Table 1 shows the etching state around the lead, and the measurement results of the initial adhesion and the high-temperature heat-resistant adhesion.
[0033]
Example 5
The same as Example 1 except that a chromium layer was formed to a thickness of 15 ° as a first seed layer, and a nickel-chromium alloy layer having a chromium concentration of 20% by weight was formed to a thickness of 20 ° as a second seed layer. Under the conditions, a copper-coated polyimide substrate was manufactured. Table 1 shows the etching state around the lead, and the measurement results of the initial adhesion and the high-temperature heat-resistant adhesion.
[0034]
Example 6
The same conditions as in Example 1 were used except that a chromium layer was formed to a thickness of 15 ° as a first seed layer, and a nickel-chromium alloy having a chromium concentration of 20% by weight was formed to a thickness of 120 ° as a second seed layer. A copper-coated polyimide substrate was manufactured. Table 1 shows the etching state around the lead, and the measurement results of the initial adhesion and the high-temperature heat-resistant adhesion.
[0035]
Example 7
The same as Example 1 except that a chromium layer was formed to a thickness of 15 ° as a first seed layer, and a nickel-chromium alloy layer having a chromium concentration of 35% by weight was formed to a thickness of 50 ° as a second seed layer. Under the conditions, a copper-coated polyimide substrate was manufactured. Table 1 shows the etching state around the lead, and the measurement results of the initial adhesion and the high-temperature heat-resistant adhesion.
[0036]
Comparative Example 1
A copper-coated polyimide substrate was prepared under the same conditions as in Example 1, except that a nickel chromium alloy layer having a chromium concentration of 7% by weight and a thickness of 100 mm was directly formed on the polyimide without forming the chromium layer of the first seed layer. Manufactured. Table 1 shows the etching state around the lead, and the measurement results of the initial adhesion and the high-temperature heat-resistant adhesion.
[0037]
Comparative Example 2
A copper-coated polyimide substrate was manufactured under the same conditions as in Example 1 except that a chromium layer was formed to a thickness of 35 ° as a first seed layer. Table 1 shows the etching state around the lead, and the measurement results of the initial adhesion and the high-temperature heat-resistant adhesion.
[0038]
Comparative Example 3
A copper-coated polyimide substrate was manufactured under the same conditions as in Example 1 except that a chromium layer was formed as a first seed layer to a thickness of 15 ° and a nickel-chromium alloy layer as a second seed layer was not formed. . Table 1 shows the etching state around the lead, and the measurement results of the initial adhesion and the high-temperature heat-resistant adhesion.
[0039]
Comparative Example 4
The same as Example 1 except that a chromium layer was formed to a thickness of 15 ° as a first seed layer, and a nickel-chromium alloy layer having a chromium concentration of 7% by weight was formed to a thickness of 400 ° as a second seed layer. Under the conditions, a copper-coated polyimide substrate was manufactured. Table 1 shows the etching state around the lead, and the measurement results of the initial adhesion and the high-temperature heat-resistant adhesion.
[0040]
Comparative Example 5
The same as Example 1 except that a chromium layer was formed to a thickness of 15 ° as a first seed layer, and a nickel-chromium alloy layer having a chromium concentration of 35% by weight was formed to a thickness of 300 ° as a second seed layer. Under the conditions, a copper-coated polyimide substrate was manufactured. Table 1 shows the etching state around the lead, and the measurement results of the initial adhesion and the high-temperature heat-resistant adhesion.
[0041]
Comparative Example 6
The same as Example 1 except that a chromium layer was formed to a thickness of 15 ° as a first seed layer, and a nickel-chromium alloy layer having a chromium concentration of 45% by weight was formed to a thickness of 100 ° as a second seed layer. Manufactured under conditions. Table 1 shows the etching state around the lead, and the measurement results of the initial adhesion and the high-temperature heat-resistant adhesion.
[0042]
[Table 1]

[0043]
As is clear from Table 1, in Examples 1 to 7, the chromium layer (first seed layer) has a thickness of 5 to 25 ° and a chromium concentration of less than 15% by weight. When the thickness of the two-seed layer is 10 ° or more and 300 ° or less, or when the thickness of the chromium layer (first seed layer) is 5 ° or more and 25 ° or less and the chromium concentration is 15% by weight or more and 40% by weight or less. When the thickness of a certain nickel chromium alloy layer (second seed layer) is 10 ° or more and 150 ° or less, the etching state around the lead is good without remaining the seed layer, the initial adhesive strength is 600N / m or more, and the high temperature heat resistant adhesiveness is obtained. It can be seen that a copper-coated polyimide substrate having a force of 500 N / m or more can be obtained. On the other hand, in Comparative Examples 1 to 6, since the structure or the film thickness of the seed layer does not meet these conditions, satisfactory results are obtained in either the etching state around the lead or the high-temperature heat-resistant adhesion. You can see that it can not be done.
[0044]
【The invention's effect】
As described above, the copper-coated plastic substrate of the present invention can be patterned by an etching method using an iron chloride solution or a copper chloride solution, and has a thickness of 8 μm of the copper conductor, and has an initial adhesion force of 350 ° C. Both are high heat resistant two-layer plated substrates having a high temperature resistance of 500 N / m or more after thermocompression bonding in a temperature range of 450 ° C. for 10 seconds, and their industrial value is extremely large.

Claims (4)

A seed layer is formed on a plastic film on a copper-coated plastic substrate in which a seed layer is formed directly on both sides or one side of a plastic film without using an adhesive, and a copper conductor layer is formed on the seed layer. A first seed layer made of a chromium layer having a thickness of 5 ° to 25 °, and a chromium concentration in the nickel-chromium alloy of less than 15% by weight having a thickness formed on the first seed layer of 10 ° to 300 °, or And a second seed layer comprising a nickel-chromium alloy layer having a thickness of 10 to 150% and a chromium concentration in the nickel-chromium alloy of 15 to 40% by weight. substrate. The copper-coated plastic substrate according to claim 1, wherein the first seed layer and the second seed layer are formed by a sputtering method. The copper-coated plastic substrate according to claim 1, wherein the plastic film is a polyimide film. The high-temperature heat-resistant adhesive force after heat-press bonding for 10 seconds in a temperature range of 350 to 450 ° C. at a thickness of 8 μm of the copper conductor layer is 500 N / m or more, according to any one of claims 1 to 3, wherein A copper-coated plastic substrate according to the above.