JP2006310401A - Manufacturing method for printed-circuit board and chemical - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treating method for shaving off a board base material containing a first metallic layer by using a liquid containing no heavy metal when the printed-circuit substrate is manufactured as a raw material for an electronic part such as a printed-circuit board, a flexible printed board a TAB tape, a COF tape or the like. <P>SOLUTION: A metallic-film polyimide-resin film has the first metallic layer formed on one surface or both surfaces of a polyimide-resin film by a dry type film formation method and a second metallic layer being formed on the first metallic layer by an electroplating or an electroless plating and having a conductivity. In such a metallic-film polyimide-resin film, a pattern treatment is conducted, and a pretreatment by an irradiation for improving a wettability required for permeating a treatment liquid in a small-wire pattern is conducted. In such a film, a polyimide resin in space sections among leads is etched up to a depth in a submicron order by an alkali etchant and the residues of a metal are removed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a printed wiring board that is a material for electronic components such as a printed wiring board, a flexible printed board, a TAB tape, and a COF tape, and a chemical used at that time.

  A printed wiring board made of a polyimide resin film has excellent heat resistance and is comparable to other plastic materials in mechanical, electrical, and chemical characteristics. For example, PWB (printed wiring board), FPC (Flexible printed circuit board), TAB (tape for automatic tape bonding), COF (chip on film), etc., are widely used as insulating substrate materials for electronic components.

  Such an insulating substrate material can be obtained by processing a printed wiring board made of a metal layer-coated polyimide resin film in which at least one surface of a printed wiring board made of a polyimide resin film is mainly coated with copper as a metal conductor layer. The printed wiring board made of this metal layer-coated polyimide resin film includes a three-layer board obtained by bonding a printed wiring board made of a polyimide resin film and a metal foil with an adhesive, a casting board or a polyimide that applies a polyimide varnish to the metal foil. There is a two-layer board in which a metal layer is directly formed on a printed wiring board made of a resin film.

  At present, a printed wiring board made of a polyimide resin film and a two-layer board in which the thickness of the metal layer can be freely set have been attracting attention because of the relatively high adhesion at the bonding interface. In particular, after forming a plasma polymerized film on the surface of a printed wiring board made of polyimide film, a two-layer substrate by a metalizing method in which a metal thin film is directly formed on the surface of the printed wiring board made of polyimide film by performing vacuum deposition and electrolytic plating, The interface of a printed wiring board made of a metal-coated polyimide resin film is very smooth, and is particularly suitable for an insulating board material patterned with a recent fine wiring pitch.

In recent miniaturization of wiring accompanying high-density mounting, the insulation reliability of the printed wiring board is an important management item, and an insulation reliability test by a constant temperature / humidity bias test is performed.
Under such circumstances, the two-layer substrate by the metallization method modifies the surface of the printed wiring board made of the polyimide resin film and improves the adhesion with the first metal layer, so that the printed board made of the polyimide resin film The bonding strength between the wiring board and the first metal layer is strong, and the metal layer component remains on the surface of the printed wiring board made of a polyimide resin film even after pattern processing using a method such as additive or subtracting. Many remain and are likely to cause ion migration.

For example, 130 degreeC-85% R. H. When the insulation reliability test was performed by applying a bias of 60 volts in the constant temperature / humidity layer, the wiring pitch was 50 micrometer (L [line] / S [space] = 25 micrometer / 25 micrometer). The fact is that the insulation reliability can only be maintained for 100 hours or less.
As described in the reference patent document (Japanese Patent Laid-Open No. 2003-188495), the conventional countermeasures for dealing with this are described in the following. Pattern processing is performed on the substrate using an oxidizing agent such as potassium permanganate and potassium dichromate. Although the oxidation treatment was performed after the treatment, it was a technique using heavy metals, which left problems in the manufacturing process and environmental measures.

  The present invention finds a method of processing without containing the heavy metal, and is a method that has less influence on the environment than the conventional method as described above, and on the surface of the printed wiring board that is sufficiently made of a metal layer-coated polyimide resin film. The purpose is to propose a construction method that can efficiently remove many remaining metal components.

JP 2003-188495 A

  A plasma polymerized film is formed on the surface of a printed wiring board made of polyimide resin film on one or both sides of a printed wiring board made of polyimide resin film, and then vacuum-deposited or electroplated to form the surface of the printed wiring board made of polyimide resin film. A first metal layer formed of Ni, Cu, Mo, Ta, Ti, V, Cr, Fe or Co and alloys thereof in a dry film forming method including a metalizing method for directly forming a metal thin film; On a printed wiring board made of a metal layer-coated polyimide resin film having a second metal layer having good conductivity typified by Cu formed thereon by electroplating or electroless plating, an additive method or a subtract method Even after pattern processing using a method such as Cause the migration phenomenon. In particular, recent fine patterns are a major factor in losing insulation reliability.

  Conventionally, after the pattern treatment, a technique of oxidizing the surface using an oxidizing agent such as potassium permanganate or potassium dichromate is used as a residue treatment. Therefore, it had a great influence on the environmental problems including the work environment.

  A first metal layer formed by a dry film forming method such as a metallizing method on one or both sides of a printed wiring board made of a polyimide resin film, and Cu or the like formed by electroplating or electroless plating on the first metal layer After forming a pattern using a method such as the additive method or the subtract method on a printed wiring board made of a metal-coated polyimide resin film having a second metal layer having conductivity represented by In order to remove water, an inorganic alkali compound composed of 30% by weight or less and 10% by weight or more of an alkali metal hydroxide and at least one amino group and a hydroxyl group in a molecule of 40% by weight or more and 80% by weight or less It is composed of an aliphatic amino alcohol and water, and has a total alkali component concentration, that is, the inorganic alkali compound and the aliphatic alcohol. Presenting means to manufacture printed wiring board made of polyimide resin film with high insulation reliability without any residue by polyimide etching using aqueous solution whose total alcohol content is 70 wt% or more and 90 wt% or less To do.

  The polyimide etching solution is a solution in which the alkali hydroxide is at least one of potassium hydroxide and sodium hydroxide, and the aliphatic amino alcohol is 2-aminoethanol. A printed wiring board made of a resin film is manufactured.

  As a method for obtaining the insulation reliability, polyimide etching is performed, but before that, it is better to perform pretreatment in order to improve the wettability of the printed wiring board made of the polyimide resin film. As the pretreatment, irradiation by activation irradiation (such as UV irradiation, excimer irradiation, or oxygen plasma irradiation) is effective.

  When a pattern is formed on a printed wiring board made of a polyimide resin film using an additive method, a subtract method, or the like, the pattern formation grade is performed under optimum conditions, and then the first printed wiring board made of a polyimide resin film is placed on the printed wiring board. A method of manufacturing a printed wiring board made of a metal-coated polyimide resin film by performing a polyimide etching operation by contacting with an etching solution at a liquid temperature of 20 ° C. or lower and 40 ° C. or lower when performing polyimide etching for removing residues remaining on the metal layer. Is effective for residue treatment.

  In addition, after forming a pattern using a method such as the additive method or the subtract method, a polyimide etching solution under optimum conditions for residue treatment is formed on one or both sides of a printed wiring board made of a polyimide resin film. Print for forming the pattern on a printed circuit board made of a metal-coated polyimide resin film having a conductive second metal layer electroplated or electrolessly plated on a first metal layer formed by a film method In the method of manufacturing a wiring board, a pretreatment consisting of irradiation is performed as an activation for improving wettability, and an inorganic alkali compound composed of 30 wt% or less and 10 wt% or more of an alkali metal hydroxide, and 40 wt% or more Aliphatic amino alcohol having at least one amino group and hydroxyl group in 80% by weight or less of the molecule It consists le and water, and is preferable to use a total of at most 90 wt% 70 wt% or more liquid total alkali component concentration i.e. inorganic alkali compound and the aliphatic amino alcohol as an etching chemical.

  After patterning the metal component on the surface of the printed wiring board made of the polyimide resin film according to the present invention using a method such as an additive method or a subtract method, after activation and pretreatment by irradiation for improving wettability By performing polyimide etching and performing residue removal treatment to scrape the polyimide resin layer along with the residue on the printed wiring board made of polyimide resin film, ion migration is suppressed and excellent insulation reliability even in fine wiring A printed wiring board made of a rising metal film polyimide resin film can be manufactured.

  In addition, if this method is used, the polyimide resin layer is shaved together with the first metal layer of the printed wiring board made of the polyimide resin film, so that the residue treatment can be reliably performed and the conventional method is shown. Since no heavy metal is used, an effective effect can be obtained both in the manufacturing process and on the environment.

In the present invention, the polyimide resin film used as an insulating substrate material, for example, Toray DuPont Kapton ^R V type, the VN type, the E type or EN type, polyimide resin film manufactured by Ube Industries, Ltd. ^Upilex-S R, Or a commercially available cured film etc., such as Kaneka super polyimide resin film Apical ^R , is raised.

  As a first metal layer forming method for a printed wiring board made of a polyimide resin film, a plasma polymerized film is formed on the surface of the printed wiring board made of a polyimide resin film, and then a vacuum vapor deposition / electrolytic plating is performed to make the polyimide resin film. It is performed using metallizing technology for directly forming a metal thin film on the surface of a printed wiring board, dry plating such as counter heating vapor deposition, ion-brating vapor deposition, or sputtering vapor deposition.

  Furthermore, as the first metal layer formed on the printed wiring board made of the polyimide resin film, a laminate of nickel, cobalt, molybdenum, titan, titanium, vanadium, chromium, iron, cobalt, and alloys and oxides thereof is used. Used.

  When forming a pattern using a method such as an additive method or a subtract method on a two-layer substrate processed using the metalizing method, after forming the pattern, the space between the leads is etched or subsequently Even during the cleaning process, a trace amount of metal components directly bonded causes migration when an insulation reliability test is performed in a constant temperature and constant humidity atmosphere.

  This invention discovered the method of irradiating the irradiation which aims at activation for wettability improvement as a pre-process which carries out polyimide etching of the printed wiring board which consists of a polyimide resin film with an alkaline etching liquid.

  At that time, the thinner the pattern, the more difficult it is for the alkaline etchant to enter the space between the leads, and the etching of a printed wiring board made of a polyimide resin film does not cause a sufficient reaction, resulting in thin skin due to wrinkles. The film could not be removed and the residue could not be treated.

  Therefore, in order to improve the surface wettability and perform the reaction sufficiently, the irradiation process aiming at activation such as UV irradiation, excimer irradiation or oxygen plasma irradiation is performed as a pre-processing, leading to submicron-order patterns. Since the etchant can enter and react in the space between the lead and the lead, there is no generation of wrinkles and the thin skin film can be removed, and it is possible to provide a method for scraping and removing the polyimide resin surface containing residues It became.

  In addition, a pattern is formed on a printed wiring board made of a metal layer-coated polyimide resin film using an additive method or a subtract method, and UV irradiation, excimer irradiation or oxygen plasma irradiation is performed as a pretreatment for improving wettability. Activating irradiation is carried out by an irradiation method such as the following, and then polyimide etching of a printed wiring board made of a polyimide resin film is performed with 40% by weight of an inorganic alkali compound such as 30% by weight or less and 10% by weight or more of an alkali metal hydroxide. It is composed of an aliphatic amino alcohol having at least one amino group and a hydroxyl group in water in a molecule of not less than 80% by weight and water, and has a total alkali component concentration (total of inorganic alkali compound and amino alcohol) of 70. Performed using an aqueous solution of not less than 90% by weight.

  The specific method will be described below with reference to examples.

[Example 1] A printed wiring board made of a polyimide resin film having a thickness of 25 μm and a metal wiring made of a polyimide resin film with a single-sided copper foil having a copper thickness of 8 μm as the first metal layer. Using Royal ^R , a comb-shaped pattern with a pitch of 50 μm (L [line] / S [space] = 25 μm / 25 μm) is formed as shown in FIG. For this purpose, after excimer irradiation, polyimide etching is performed on the printed wiring board made of the polyimide resin film with the alkali etching solution, followed by hot water washing, water washing and drying, and a temperature of 130 ° C. and a humidity of 85% RH. Apply a 60-volt bias to the sample in a constant temperature and humidity atmosphere It was carried out insulation reliability test. Comparing with the result of Comparative Example 1, it can be seen that the residue made of the thin skin, wrinkles and the like of the printed wiring board made of the polyimide resin film is sufficiently removed in the space portion.

[Comparative Example 1] A Toray Film Processing Co., Ltd. Metaroyal ^R , which is a printed wiring board made of a polyimide resin film with a single-sided copper foil having a thickness of 25 micrometers and a copper thickness of 8 micrometers, is used for a printed wiring board made of a polyimide resin film. FIG. 2 shows the results in the case where a comb-shaped pattern having a pitch of 50 μm (L / S = 25 μm / 25 μm) is formed and no excimer irradiation is applied to activate the improvement of wettability. Compared with the results of Example 1, it can be seen that there is a remarkable generation of residues consisting of thin skins and wrinkles of a printed wiring board made of a polyimide resin film in the space portion.

[Comparative Example 2] printed wiring board thickness 25 micrometers made of a polyimide resin film, using a Toray Advanced Film Co., Ltd. Metaloyal ^R is a printed wiring board comprising a single-sided copper foil polyimide resin film Doatsumi 8 microns, pitch After forming a comb pattern of 50 microns (L / S = 25 microns / 25 microns) and irradiating excimer, polyimide etching is performed on the printed wiring board made of polyimide resin film with our alkali etching solution. After the application, hot water, washing with water and drying were performed, and a bias of 60 volts was applied to the sample in a constant temperature and humidity chamber at a temperature of 130 ° C. and a humidity of 85% RH, and an insulation reliability test was performed.

  According to the present invention, a method of manufacturing a printed wiring board that is a material for electronic components such as a printed wiring board, a flexible printed circuit board, a TAB tape, and a COF tape and a chemical solution used at that time are proposed, and the manufacturing of a printed wiring board with high insulation reliability Enable.

The figure which shows the printed wiring board surface state which consists of a polyimide resin film which gave the pre-etching process. The figure which shows the printed wiring board surface state which consists of a polyimide resin film which does not give a pre-etching process.

Explanation of symbols

1 Printed wiring board made of polyimide resin film 2 Printed wiring board processing part made of polyimide resin film (Space part)
3 Metal layer circuit part (Line part)
4 pattern pitch

Claims (5)

A first metal layer formed by a dry film forming method on one or both sides of a printed wiring board made of a polyimide resin film, and a second conductive layer formed by electroplating or electroless plating on the first metal layer In a printed wiring board manufacturing method for forming an etching pattern on a printed wiring board made of a metal film polyimide resin film having a metal layer, a pretreatment for improving wettability after pattern forming is performed, and 30 wt% or less and 10 wt% % Of an inorganic alkali compound composed of at least alkali metal hydroxide, an aliphatic amino alcohol having at least one amino group and a hydroxyl group in a molecule of 40 wt% or more and 80 wt% or less, and water, and Total alkali component concentration, that is, the total of the inorganic alkali compound and the aliphatic amino alcohol is 70% by weight or more Printed circuit board manufacturing method comprising a metal coating polyimide resin film characterized by applying polyimide etching using 0% by weight or less aqueous solution. 2. The print comprising a metal-coated polyimide resin film according to claim 1, wherein the alkali hydroxide is at least one of potassium hydroxide and sodium hydroxide, and the aliphatic amino alcohol is 2-aminoethanol. A method for manufacturing a wiring board. The method for producing a printed wiring board comprising the metal-coated polyimide resin film according to claim 1 or 2, wherein the pretreatment method for improving wettability is irradiation. The method for producing a printed wiring board comprising a metal-coated polyimide resin film according to any one of claims 1 to 3, wherein polyimide etching is performed at a liquid temperature of 20 ° C to 40 ° C. A first metal layer formed by a dry film forming method on one or both sides of a printed wiring board made of a polyimide resin film, and a second conductive layer formed by electroplating or electroless plating on the first metal film. In a printed wiring board manufacturing method for forming an etching pattern on a printed wiring board made of a metal film polyimide resin film having a metal layer, a pretreatment for improving wettability after pattern forming is performed, and 30 wt% or less and 10 wt% % Of an inorganic alkali compound composed of at least alkali metal hydroxide, an aliphatic amino alcohol having at least one amino group and a hydroxyl group in a molecule of 40 wt% or more and 80 wt% or less, and water, and Total alkali component concentration, that is, the total of the inorganic alkali compound and the aliphatic amino alcohol is 70% by weight or more Chemical solution used in the method for manufacturing a printed wiring board comprising a metal coating polyimide resin film characterized by applying polyimide etching using an aqueous solution at 0 wt% or less.

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