JP2009031612A - Resin substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin substrate excellent in water vapor barrier property and particularly in peel strength. <P>SOLUTION: The resin substrate comprises a resin layer and a surface layer formed on the resin layer. The surface layer comprises: (a) a first SiN layer which is formed on the surface of the resin layer and primarily comprises silicon nitride deposited at a deposition start temperature of 50°C or more according to a chemical vapor deposition method; and (b) a second SiN layer which is formed on the first SiN layer and primarily comprises silicon nitride deposited at a deposition start temperature of 170°C or less according to a chemical vapor deposition method. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin substrate member, particularly a flexible resin substrate. Specifically, for example, in addition to a general flexible printed circuit board having a wiring layer on a film, a flexible printed wiring board in which a semiconductor bare chip is directly mounted on a resin substrate, an active made of an organic semiconductor or an organic conductor. Flexible devices including elements and electrical wiring, liquid crystal display elements (LCD: Liquid Crystal Display) using resin substrates, organic electroluminescence (OLED: Organic Light Emitting Diode) displays, etc., and substrate materials such as flexible solar cells Is preferably used.

  Conventionally, an FPC board is composed of an electric wiring layer formed of a highly conductive material typified by a Cu film on a film substrate made of a resin material having excellent heat resistance, chemical resistance, and dimensional stability. FPC boards with features of weight reduction and thinning are assumed to be used in a curved state, that is, in a state where stress is applied to the highly conductive material and the film substrate surface. Among them, the adhesion strength between the film substrate and the Cu film wiring layer is very important.

  In addition, the surface of the resin substrate is insufficient in terms of water vapor and oxygen permeability because most of the Ni—Cr film and Cu film other than the pattern portion are etched away to expose the resin film.

  In addition, resin-molded semiconductor elements were often mounted on FPC boards, but they are found in high-density mounting methods called system-in-package in order to reduce costs, increase mounting density, and reduce area. As described above, a method of forming a passivation layer after mounting a bare chip without a resin mold on a resin substrate at a high density has come to be used. For this reason, in order to ensure the long-term reliability of a semiconductor element, the passivation function has become more important than ever. For such bare chip mounting, an Au—Sn alloy is generally used, and heat resistance of up to 300 ° C. has been required for the FPC substrate. Recently, the use of ultrasonic waves has been used to lower the temperature to 200 ° C. or lower, but heat resistance is still important for this application.

  In order to cope with the light weight and thinning required for portable devices in addition to FPC board applications, glass substrates in liquid crystal display elements (LCD: Liquid Crystal Display), organic electroluminescence (OLED) displays, Attempts have been made to use a resin substrate as an alternative to the above, or a resin substrate as an alternative to a silicon wafer for photovoltaic power generation elements. In the case of a film substrate, it is expected that production speed will be dramatically improved by using the roll-to-roll method by taking advantage of its flexibility and flexibility. Is done. In the case of such a high-performance electronic product, the resin substrate is required to have a water vapor barrier property in addition to the peel strength of the wiring on the substrate and the electric circuit.

The water vapor barrier property is said to be stricter to 0.1 g / m ² / day or less for an LCD, and further to 1 / 100,000 or less for an OLED, for example. Since a resin substrate alone cannot achieve the required water vapor barrier properties, a barrier thin film has been conventionally formed on the surface of a resin substrate by vacuum deposition, sputtering, or other film formation methods. Yes. Patent Documents 1 and 2 describe that a silicon nitride film formed by a catalytic chemical vapor deposition method (Cat-CVD method) exhibits good characteristics as a barrier thin film.

Patent Document 3 describes that barrier properties are improved by stacking silicon nitride oxide layers having different oxygen concentration ratios. Furthermore, Patent Document 4 describes that the barrier property is improved by making the organic layer and the inorganic layer multi-layered.
JP 2004-292877 A JP 2005-342975 A JP 2003-206361 A (Patent No. 3859518) JP 2004-314564 A

  As described above, there is a demand for a resin substrate that has both a water vapor barrier property and a peel strength necessary to ensure long-term reliability of an electronic product. That is, an object of the present invention is to provide a resin substrate having a water vapor barrier property and an excellent peel strength.

  The present invention relates to the following matters.

1. A resin substrate having a resin layer and a surface layer formed on the surface of the resin layer,
The surface layer is
(A) a first SiN layer mainly composed of silicon nitride formed on the surface of the resin layer and formed by chemical vapor deposition at a film formation start temperature of 50 ° C. or higher;
(B) having a second SiN layer mainly composed of silicon nitride formed on the first SiN layer and formed by chemical vapor deposition at a film formation start temperature of 170 ° C. or lower. Characteristic resin substrate.

  2. 2. The resin substrate as described in 1 above, wherein the first SiN layer is formed at a film formation start temperature exceeding 170 ° C.

  3. 3. The resin substrate as described in 1 or 2 above, wherein the total thickness of the first SiN layer and the second SiN layer is in the range of 20 to 1000 nm.

4). The resin substrate according to any one of the above 1-3,
An electric circuit board comprising an electric circuit layer formed on the resin substrate.

  5). 5. The electric circuit board according to 4 above, wherein the electric circuit layer has a base layer for metalizing.

  6). 6. The electric circuit board according to 5 above, wherein the electric circuit layer has a base layer for metalizing and a plating layer.

7). Forming a first SiN layer mainly composed of silicon nitride on the resin layer by a chemical vapor deposition method under a condition of a film formation start temperature of 50 ° C. or higher;
Forming a second SiN layer containing silicon nitride as a main component after the first SiN layer is formed by a chemical vapor deposition method under a condition that a film formation start temperature is 170 ° C. or lower. A method for producing a resin substrate.

  8). 8. The method according to 7 above, wherein the chemical vapor deposition method is a catalytic chemical vapor deposition method.

  9. 9. The method according to 7 or 8 above, wherein the first SiN layer is formed at a deposition start temperature exceeding 170 ° C.

  10. 10. The method according to any one of 7 to 9 above, wherein the first SiN layer and the second SiN layer are formed so that a total thickness is in a range of 20 to 1000 nm.

  Since the resin substrate of the present invention is excellent in peel strength and water vapor barrier properties, it is useful as a flexible resin substrate that requires flexibility and water vapor barrier properties. For example, high-performance electronic components such as LCDs, OLEDs, solar cells, flexible printed wiring boards in which semiconductor bare chips are directly mounted on resin substrates, and other active devices including organic semiconductors and organic conductors or flexible devices including electrical wiring It is also suitable as a substrate for electronic products. As a result, a lightweight electronic product and a flexible electronic product can be realized.

  As shown in FIG. 1, the resin substrate of the present invention has a structure in which a surface layer 2 is formed on the surface of a resin layer 1. In a typical application, an electric circuit layer 3 is formed on the surface of the surface layer 2 of the resin substrate. Further, a film 4 such as a gas barrier film or an electrode layer may be formed on the back surface of the resin layer 1 as necessary. In a typical example, as shown in FIG. 1, the surface layer has a first SiN layer 2 a in contact with the resin layer 1 and a second SiN layer 2 b laminated thereon.

  Although it is one of the preferable aspects that the resin layer is comprised only by the resin base layer 1a which has resin as a main component, such as a resin film, it may have another layer and film | membrane as needed. For example, as shown in FIG. 2, you may have the other thin film layer 5 with the resin base layer 1a.

  The thin film layer 5 can be formed of, for example, an organic material or an organic-inorganic hybrid material. For example, the purpose of improving the adhesion between the polyimide resin base layer and the surface layer, the purpose of improving the bending resistance of the surface layer, the polyimide resin base It is formed for the purpose of improving the flatness of the layer and the purpose of further improving the water vapor barrier property. Examples of the thin film layer include materials described in JP-A-2006-289627, JP-A-2006-95783, and JP-A-2006-123307. Specific examples include a resin to which an inorganic filler is added, a resin containing polyorganosilsesquioxane as a main component, polysiloxane, polyparaxylene, polyurea, an acrylate polymer, and other organic polymers.

  The surface layer 2 can be formed not only on one side of the resin layer 1 but also on both sides. In this case, the film 4 may not be present.

  As the resin base layer, a known so-called resin substrate can be used. The material is not particularly limited. For example, heat-resistant resins such as polyimide resin, liquid crystal polymer, and polyethylene naphthalate, which are used in many products as flexible wiring boards and have been confirmed to have high reliability; polyethersulfone, polycarbonate Heat-resistant transparent resins having a glass transition temperature of 100 ° C. or higher, such as polycycloolefins; thermosetting resins mainly composed of transparent epoxy resins; or hybrids obtained by adding inorganic components to thermoplastic resins or thermosetting resins Examples thereof include resins.

  As the shape of the resin base layer, the thickness may be, for example, about 1 μm to 200 μm, preferably about 5 μm to 200 μm, or may have a thickness larger than that. The resin base layer can be prepared by a known method, such as a cast method, a solution casting method such as a solution coating method, a melt extrusion method, or a vapor deposition method. Can be mentioned. Examples of the shape include a film, a sheet, and a flat plate. Preferred are an available polyimide film, polyamide film, polyamideimide film, and the like, and more preferred is a polyimide film.

  Although a well-known thing can be used as a polyimide film, The thing which is excellent in heat resistance and intensity | strength especially, and has a thermal expansion coefficient with a good consistency with an electronic circuit layer is preferable. Specific examples of the polyimide film include the product name “UPILEX (S or R)” (manufactured by Ube Industries), the product name “Kapton” (manufactured by Toray DuPont and DuPont), and the product name “APICAL” (Kaneka). And polyimide films obtained from an acid component and a diamine component constituting these films.

Specifically, as polyimide,
(1) 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride and 1,4-hydroquinone dibenzoate-3,3 ′, 4,4′-tetracarboxylic acid bis An acid component containing at least one component selected from anhydrides, preferably an acid component containing at least 70 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more of these acid components;
(2) As a diamine component, a diamine containing at least one component selected from p-phenylenediamine, 4,4′-diaminodiphenyl ether, m-tolidine and 4,4′-diaminobenzanilide, preferably at least these diamine components A polyimide obtained from a diamine component containing 70 mol% or more, more preferably 80 mol% or more, and more preferably 90 mol% or more can be used.

As an example of a combination of an acid component and a diamine component,
1) 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, p-phenylenediamine or p-phenylenediamine and 4,4-diaminodiphenyl ether,
2) 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride, p-phenylenediamine or p-phenylenediamine and 4,4-diaminodiphenyl ether,
3) pyromellitic dianhydride, p-phenylenediamine and 4,4-diaminodiphenyl ether,
4) What can be obtained by using 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine as main components (50 mol% or more in a total of 100 mol%) can be mentioned. These are used as materials for electronic components such as printed wiring boards, flexible printed circuit boards, TAB tapes, etc., and have excellent mechanical properties over a wide temperature range, long-term heat resistance, and hydrolysis resistance It is preferable because it has excellent heat resistance, a high thermal decomposition starting temperature, a small heat shrinkage rate and a low coefficient of linear expansion, and excellent flame retardancy.

  As the acid component, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-, as long as the properties of the present invention are not impaired in addition to the acid components shown above. Benzophenone tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfide dianhydride, bis (3,4-dicarboxyphenyl) sulfone Anhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) ) Acid dianhydride components such as 1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis [(3,4-dicarboxyphenoxy) phenyl] propane dianhydride Using It is possible.

  As the diamine component, m-phenylenediamine, 3,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl sulfide, 3,4′-diamino, as long as the characteristics of the present invention are not impaired in addition to the diamine component shown above. Diphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 4,4 '-Diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2-di (3-aminophenyl) propane, 2,2-di (4-aminophenyl) propa It can be used diamine component, such as.

  The surface layer includes (a) a first SiN layer mainly composed of silicon nitride formed by chemical vapor deposition at a film formation start temperature of 50 ° C. or higher, and (b) chemical vapor deposition. And a second SiN layer mainly composed of silicon nitride formed at a film start temperature of 170 ° C. or lower. The first SiN layer is formed in close contact with the resin layer. By setting the film formation start temperature to 50 ° C. or higher, the adhesion between the resin layer and the surface layer is improved, and a resin substrate having a high peel strength can be obtained. The first SiN layer is a layer mainly having a function of improving adhesion, and the film formation start temperature is more preferably 70 ° C. or higher, and further preferably 90 ° C. or higher. In certain forms, temperatures above 170 ° C. are employed. The upper limit of the film formation start temperature is allowed up to the heat resistant temperature of the resin layer and depends on the material of the resin layer, but when using a polyimide resin, for example, 350 ° C. or less, preferably 300 ° C. or less, more preferably 270 ° C. or less. It is.

  The second SiN layer is a layer that is formed on the first SiN layer (in close contact with the preferred embodiment) and mainly has a function of improving the water vapor barrier property, and the film formation start temperature is 170 ° C. or lower. More preferably, it is 150 ° C. or less, particularly preferably 100 ° C. or less. Moreover, although it may cool as needed, generally it forms into a film at the temperature more than ambient temperature (for example, temperature of 15-30 degreeC).

  In the present specification, when the present invention is described, the terms “first SiN layer” and “second SiN layer” are respectively referred to as “deposition start temperature (resin layer) by chemical vapor deposition, unless otherwise specified. Layer having silicon nitride as a main component formed at a temperature of 50 ° C. or higher ”,“ silicon nitride formed by chemical vapor deposition at a film formation start temperature (resin layer temperature) of 170 ° C. or lower. ”, And preferably a layer formed under the above conditions. Further, the “first SiN layer” and the “second SiN layer” may be collectively referred to as “SiN layer”. Further, the terms “silicon nitride layer”, “silicon nitride thin film” and the like include other silicon nitrides in addition to the layers satisfying the conditions of “first SiN layer” and “second SiN layer” defined above. It is used in the meaning of including a layer as a main component.

  The first and second SiN layers may contain, as a constituent material, Al oxide, Si oxide, or the like conventionally used as an additive in addition to silicon nitride. The proportion of silicon nitride in these SiN layers is generally 30 atomic% or higher, preferably 50 atomic% or higher, more preferably 70 atomic% or higher, and even more preferably 90 atomic% or higher.

  Although it is known that a thin film mainly composed of silicon nitride exhibits a water vapor barrier property even if it is very thin, considering the coverage of the resin layer surface, the total of the first SiN layer and the second SiN layer The thickness is preferably 20 nm or more, and more preferably 30 nm or more. On the other hand, if it is too thick, cracks are likely to occur, and it is usually preferably 1000 nm or less, more preferably 500 nm or less, and even more preferably 200 nm or less in view of productivity. The thickness of the first SiN layer is 5 nm or more, preferably 10 nm or more, more preferably 20 nm or more. The thickness of the second SiN layer is preferably 10 nm or more, more preferably 20 nm or more.

  Silicon nitride constituting the SiN layer is advantageous in the display field from the viewpoint of transparency, and is also preferable from the viewpoint of chemical resistance. The refractive index at the He-Ne laser wavelength is generally in the range of 1.80 to 2.05.

In general, as a method for forming a thin film containing silicon nitride as a main component, a physical vapor deposition method such as a vacuum vapor deposition method, a sputtering method, or an ion plating method, a plasma CVD method, a catalytic chemical vapor deposition method (Cat-CVD method). Chemical vapor deposition (chemical vapor deposition) and the like are known. However, for example, in the physical vapor deposition method, a water vapor transmission rate of 1 g / m ² / day is realized, but the barrier property may be insufficient for this purpose. In general, the vacuum deposition method is excellent in film formation speed, but the strength of the thin film itself is weak, and there are problems in process such as peeling in the flexible device formation process and it is difficult to ensure long-term reliability. . In sputter and ion plating methods, the strength of the thin film itself is higher than that of the vacuum deposition method, but large residual stress tends to remain in the thin film, which tends to cause deformation such as warping and curling in the resin substrate after film formation. .

  Therefore, in the present invention, the first and second SiN layers formed on the surface of the resin layer are preferably formed by chemical vapor deposition from the viewpoint of barrier properties, adhesion, and residual stress. A Cat-CVD method that does not require a power high-frequency power source and has a high film formation rate and is advantageous for mass production is preferable.

  As long as the first SiN layer is formed in close contact with the resin layer as the layer structure of the surface layer, the surface layer may have another silicon nitride layer and / or other thin film layer. . In the preferred embodiment, the second SiN layer is formed in close contact with the first SiN layer, but other layers are interposed between the first SiN layer and the second SiN layer. It may be.

  FIG. 3 shows an example in which the surface layer 2 includes a first SiN layer 2a and layers 7-1 to 7-n. In this case, the second SiN layer may be any one of the layers 7-1 to 7-n. The other layers of the layers 7-1 to 7-n are preferably composed of a silicon nitride layer or a thin film layer formed of an organic material or an organic-inorganic hybrid material. For example, a layer structure in which the layer 7-1 in contact with the first SiN layer 2a is a thin film layer formed of an organic material or an organic-inorganic hybrid material and the layer 7-2 is a second SiN layer is possible. The layers 7-1 to 7-n (n is 2 or more, for example, 5 or less) may all be silicon nitride layers. At this time, even if the layer 7-1 is a second SiN layer, The layer may be a second SiN layer. Examples of the organic material and the organic-inorganic hybrid material include materials described in JP 2006-289627 A, JP 2006-95783 A, and JP 2006-123307 A. Specific examples include a resin to which an inorganic filler is added, a resin containing polyorganosilsesquioxane as a main component, polysiloxane, polyparaxylene, polyurea, an acrylate polymer, and other organic polymers. In such a multilayer structure, the resin layer may have a thin film layer 5 on the surface of the resin base layer 1a as shown in FIG.

  FIG. 5 shows still another configuration example of the surface layer. In this example, a first SiN layer 2a and a second SiN layer are continuously formed on the surface of a resin layer (an example having a thin film layer 5 on the surface), and a thin film layer 8-1 and a nitride layer are formed thereon. A silicon layer 8-2 and a silicon nitride layer 8-3 are laminated, and if necessary, a thin film layer 8- (n-2), a silicon nitride layer 8- (n-1), and a silicon nitride layer 8-n ( n represents 6, 9, 12, etc.). Here, the thin film layer 8-1 and the like are thin film layers formed of the organic material or the organic-inorganic hybrid material.

  In some cases, the peel strength can be further improved by multilayering the surface layer. In addition, when the surface layer is multilayered, the silicon nitride layer is formed under different conditions even if the first SiN layer and / or the second SiN layer satisfy the same film forming conditions. But either is fine.

  Moreover, you may have an adhesive bond layer etc. in the surface which contact | connects an electric circuit layer, for example.

  The resin substrate of this invention comprised in this way is excellent in peeling strength. The peel strength is quantified by 90 ° peel strength, which is usually measured by an evaluation method according to JISC5016, and it is empirically necessary that a strength of 500 to 300 N / mm is necessary in practice. In order to estimate a long-term change in peel strength, the 90 ° peel strength after holding at 150 ° C. for 168 hours in the air may also be used as an index. In the resin substrate of the present invention, the 90 ° peel strength between the surface layer and the resin layer is preferably 300 N / mm or more, and more preferably, the 90 ° peel strength after holding in the atmosphere at 150 ° C. for 168 hours is also 300N. / Mm or more. The peel strength can be measured after, for example, forming a copper wiring layer (corresponding to an electric circuit layer).

Furthermore, the resin substrate of the present invention exhibits a water vapor barrier property of 0.1 g / m ² / day or less. As described above, the resin substrate of the present invention is composed of a multilayer in which the surface layer includes a silicon nitride layer other than the first and second SiN layers, or a combination of an organic film and / or an inorganic / organic hybrid film (composite film). However, according to one embodiment of the present invention, even when the surface layer is composed of the first and second SiN layers, the water vapor barrier is 0.1 g / m ² / day or less. Sex can be achieved. Furthermore, the average surface roughness Ra of the surface layer is preferably 1 nm or less.

  In addition, it is preferable that the glass transition temperature (especially regarding the resin material) of each material used by this invention is 100 degreeC or more, especially 200 degreeC or more.

  The electric circuit board of this invention has said resin substrate and the electric circuit layer formed on the resin substrate. The electric circuit layer is not particularly limited, and examples thereof include a transparent electrode such as ITO, copper wiring, aluminum wiring, a base layer for metallizing (see below), and combinations thereof. The electric circuit layer includes both those formed on the entire surface and those patterned in a wiring shape. In a general FPC board, a copper layer (copper wiring) having a high electric conductivity is used. The copper layer is preferably formed directly on the surface layer by a metallizing method, not by bonding through an adhesive layer. In the metalizing method, a copper thin film as a seed layer is formed by a sputtering method, an electroless plating method, or the like, and then a copper layer having a desired thickness is formed by electrolytic plating. When forming a copper layer, in order to improve peeling strength, it is preferable to form a base layer on a resin substrate.

  The underlayer for metallizing only needs to have conductivity and adhesion with no problem in practical use with the surface layer. Further, the adhesion with no problem in practical use with the metal plating layer provided on the upper surface of the undercoat layer. What is necessary is just to have. The underlayer can be formed by a known method such as vacuum deposition, sputtering, ion plating, or electron beam.

  The material of the underlayer is not particularly limited, but is a metal such as copper, nickel, chromium, manganese, aluminum, iron, molybdenum, cobalt, tungsten, vanadium, titanium, tantalum, or an alloy thereof, or oxidation of those metals. Products, carbides of these metals, and the like. Particularly preferred is NiCr. The thickness of the underlayer can be appropriately selected according to the purpose of use, and is preferably in the range of 1 to 500 nm, more preferably 5 to 200 nm because it is suitable for practical use. The number of base layers can be appropriately selected according to the purpose of use, and may be one layer, two layers, or three or more layers.

  On such an underlayer, a metal plating layer such as copper or tin can be provided by a known wet plating method such as electrolytic plating or electroless plating. Further, prior to the formation of the metal plating layer, it is also preferable to form a thin film of copper, tin, or the like, for example, by sputtering. The thickness of the metal plating layer such as copper plating is preferably in the range of 1 μm to 40 μm because it is suitable for practical use.

  By forming such a base layer, the peel strength between the surface layer and the electric circuit layer is improved, and a practical strength can be obtained. In applications such as flexible displays and solar cells where transparency of the substrate is important, a transparent conductive film typified by an ITO film is formed in the electric circuit layer. As in the case of the Cu film, the underlayer can be used as long as important functions such as transparency are not impaired.

<Deposition of silicon nitride thin film (SiN layer)>
As the resin layer, a polyimide film (Upilex film manufactured by Ube Industries, Ltd., S type, film thickness 50 μm) was used. A silicon nitride thin film was formed by the Cat-CVD method. When only silane gas and ammonia gas were used as the source gas, the amount of silane gas introduced was 7.5 sccm and the amount of ammonia gas introduced was 200 scccm. When hydrogen gas was added to improve the film quality, the silane gas flow rate was 7.5 sccm, the ammonia gas flow rate was 50 sccm, and the hydrogen gas flow rate was 200 sccm. As a raw material gas decomposition catalyst, a tungsten wire having a wire diameter of 0.5 mmφ was arranged so as to have a uniform film thickness distribution, and was heated to 1700 ° C. during film formation.

  After introducing ammonia gas and hydrogen gas to stabilize the inside of the chamber, film formation was started by introducing silane gas. At this time, the substrate holder temperature on which the polyimide film was placed was defined as the film surface temperature at the start of film formation. Other film formation conditions such as gas pressure, film surface temperature at the start of film formation, and growth time are as follows: the refractive index of the silicon nitride thin film at the He—Ne laser wavelength is 1.80 to 2.05, and the film thickness is 50 nm. The thickness was set to 100 nm.

<Refractive index measurement method>
A sample obtained by forming a silicon nitride thin film on a silicon wafer under the same conditions as those for the polyimide film was measured with an ellipsometer using a He—Ne laser as a light source.

<Water vapor barrier property evaluation>
For the evaluation of water vapor barrier properties, a resin substrate in which a silicon nitride thin film was formed only on one side of a polyimide film by the Cat-CVD method was used. For the analysis, PERMATRAN-W3 / 31 manufactured by Modern Control Co., Ltd. was used, the measurement conditions were 40 ° C. and 90% RH, and the measurement area was 50 mm ² . The lower limit of detection at this time is 0.02 g / m ² / day.

<90 ° peel strength test>
On the silicon nitride thin film formed by the Cat-CVD method, a NiCr thin film having a thickness of 5 nm is formed by high frequency sputtering, and then a Cu thin film is continuously formed by 300 nm. Thereafter, a 8 μm thick Cu film was plated in a copper sulfate plating solution bath to prepare a test sample. The test was conducted according to JIS C 6471.

<Peeling interface identification>
Fluorescent X-ray analysis was performed on the polyimide film release surface of the sample subjected to the 90 ° peel strength test, and the interface was identified by the detected element.

<Depth composition analysis>
Measurement was carried out using a Quantum 2000 scanning X-ray photoelectron spectrometer manufactured by PHI. The composition analysis was performed using the relative sensitivity factors provided by PHI for the main constituent elements, detecting the Si2p, N1s, O1s, and C1s peaks with an analysis region of 100 μm × 100 μm. The atomic concentration profile in the depth direction can be obtained by repeating the ion etching of argon gas and the above composition analysis at appropriate intervals from the surface of the silicon nitride film to the inside of the polyimide film. The area, acceleration voltage, ion beam profile, etc. are set in the ion etching area with argon gas so that the analysis area has sufficient flatness.

<Example 1>
Silicon nitride thin film containing silicon nitride as the main component, using polyimide upilex S film (50 μm thick) as the resin substrate, setting the substrate temperature at the start of film formation to 200 ° C., and setting the gas pressure at the time of film formation to 4 Pa After forming the layer (SiN layer) to a film thickness of 50 nm, the second silicon nitride thin film layer (SiN layer) having a film thickness of 50 nm is continuously formed by setting the substrate temperature to 100 ° C. and the gas pressure to 30 Pa, A surface layer having a total film thickness of 100 nm was obtained. On this surface layer, a NiCr film having a thickness of 5 nm and a Cu film having a thickness of 300 nm were formed by sputtering, and then a Cu film having a thickness of 8 μm was formed by electroplating to obtain a sample. Table 1 shows the results of a 90 ° peel test immediately after the sample and the test results after aging treatment at 150 ° C. for 168 hours in the air. The water vapor transmission rate is also shown in Table 1. In the measurement of the water vapor transmission rate, a material having no metal layer formed on the silicon nitride thin film was used. The same applies to the following examples.

<Example 2>
Silicon nitride thin film containing silicon nitride as the main component using polyimide Upilex S film (50 μm thick) as the resin substrate, setting the substrate temperature at the start of film formation to 200 ° C., and setting the gas pressure at the time of film formation to 4 Pa After forming the layer (SiN layer) to a film thickness of 50 nm, the substrate temperature is set to 30 ° C., the gas pressure is set to 30 Pa, and a silicon nitride thin film layer having a film thickness of 50 nm is continuously formed. Obtained. A NiCr film having a thickness of 5 nm and a Cu film having a thickness of 300 nm were formed on the surface layer by sputtering, and then a Cu film having a thickness of 8 μm was formed by electroplating to obtain a sample. The results are shown in Table 1.

<Example 3>
Silicon nitride thin film containing silicon nitride as the main component using polyimide Iupilex S film (50 μm thick) as the resin substrate, setting the substrate temperature at the start of film formation to 100 ° C., and setting the gas pressure at the time of film formation to 4 Pa After the layer (SiN layer) is formed to a film thickness of 50 nm, the film is once taken out from the film formation apparatus to the atmosphere and returned to the film formation apparatus again, and the substrate temperature is set to 100 ° C. and the gas pressure is set to 30 Pa to continuously form the film. A silicon nitride thin film layer (SiN layer) having a thickness of 50 nm was formed to obtain a surface layer having a total thickness of 100 nm. A NiCr film having a thickness of 5 nm and a Cu film having a thickness of 300 nm were formed on the surface layer by sputtering, and then a Cu film having a thickness of 8 μm was formed by electrolytic plating. The results are shown in Table 1.

<Comparative Example 1>
Table 1 shows the water vapor transmission rate of the polyimide Upilex S film used in Examples and Comparative Examples.
It was shown to.

<Comparative Example 2>
Silicon nitride thin film containing silicon nitride as the main component, using polyimide upilex S film (50 μm thick) as the resin substrate, setting the substrate temperature at the start of film formation to 30 ° C., and the gas pressure at the time of film formation to 30 Pa The layer was formed to a thickness of 100 nm. On this thin film layer, a NiCr film having a thickness of 5 nm and a Cu film having a thickness of 300 nm were formed by sputtering, and then a Cu film having a thickness of 8 μm was formed by electrolytic plating to obtain a sample. The results are shown in Table 1.

<Comparative Example 3>
Silicon nitride thin film composed mainly of silicon nitride using polyimide Iupirix S film (50 μm thick) as the resin substrate, setting the substrate temperature at the start of film formation to 200 ° C., and the gas pressure at the time of film formation to 30 Pa A layer (SiN layer) was formed to a thickness of 100 nm. On this thin film layer, a NiCr film having a thickness of 5 nm and a Cu film having a thickness of 300 nm were formed by sputtering, and then a Cu film having a thickness of 8 μm was formed by electrolytic plating to obtain a sample. The results are shown in Table 1.

<Reference Example 1>
In the same sample as Comparative Example 3, a 300 nm Cu film was directly formed on the silicon nitride thin film layer by sputtering without forming a NiCr film, and then a Cu film thickness of 8 μm was formed by electrolytic plating. . The results are shown in Table 1.

  Moreover, although the example which laminated | stacked by changing gas pressure was shown in the above example, even if it formed into a film with the same gas pressure, it was the same result. When the film formation start temperature was 100 ° C. and the film thickness was 100 nm, the water vapor transmission rates at the gas pressures of 4 Pa and 30 Pa were the same.

Furthermore, when composition analysis in the depth direction was performed from the silicon nitride thin film layer of the sample obtained in the above example, even if two silicon nitride thin film layers were formed, the elements in the silicon nitride thin film layer on the resin layer side The result that the concentration ratio O / (O + N) was smaller than the element concentration ratio O / (O + N) in the second silicon nitride thin film layer was not obtained.

It is a figure which shows one example of a resin substrate. It is a figure which shows one example of a resin substrate. It is a figure which shows one example of a resin substrate. It is a figure which shows one example of a resin substrate. It is a figure which shows one example of a resin substrate.

Explanation of symbols

1 resin layer 1a resin base layer 2 surface layer 2a first SiN layer 2b second SiN layer 3 electric circuit layer 4 film (gas barrier film, electrode layer, etc.)
5 Thin film layers 7-1 to 7-n layers (silicon nitride layers, thin film layers)
8-1 to 8-n layers (silicon nitride layer, thin film layer)

Claims (10)

A resin substrate having a resin layer and a surface layer formed on the surface of the resin layer,
The surface layer is
(A) a first SiN layer mainly composed of silicon nitride formed on the surface of the resin layer and formed by chemical vapor deposition at a film formation start temperature of 50 ° C. or higher;
(B) having a second SiN layer mainly composed of silicon nitride formed on the first SiN layer and formed by chemical vapor deposition at a film formation start temperature of 170 ° C. or lower. Characteristic resin substrate.   2. The resin substrate according to claim 1, wherein the first SiN layer is formed at a film formation start temperature exceeding 170 ° C. 3.   The resin substrate according to claim 1 or 2, wherein a total thickness of the first SiN layer and the second SiN layer is in a range of 20 to 1000 nm. The resin substrate according to any one of claims 1 to 3,
An electric circuit board comprising an electric circuit layer formed on the resin substrate.   The electric circuit board according to claim 4, wherein the electric circuit layer has a base layer for metalizing.   6. The electric circuit board according to claim 5, wherein the electric circuit layer has a base layer for metalizing and a plating layer. Forming a first SiN layer mainly composed of silicon nitride on the resin layer by a chemical vapor deposition method under a condition of a film formation start temperature of 50 ° C. or higher;
Forming a second SiN layer containing silicon nitride as a main component after the first SiN layer is formed by a chemical vapor deposition method under a condition that a film formation start temperature is 170 ° C. or lower. A method for producing a resin substrate.   The method according to claim 7, wherein the chemical vapor deposition method is a catalytic chemical vapor deposition method.   The method according to claim 7 or 8, wherein the first SiN layer is formed at a film formation start temperature exceeding 170 ° C.   The method according to claim 7, wherein the first SiN layer and the second SiN layer are formed so that a total thickness is in a range of 20 to 1000 nm.

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