JP4472609B2 - Printed circuit board manufacturing method using board connecting tape - Google Patents

Description

  The present invention relates to a method for manufacturing a printed circuit board. More specifically, the present invention relates to a method for manufacturing a printed circuit board, in which a sheet-like substrate material is conductively connected, and can be subjected to electrolytic plating, electrodeposition, and the like, and then can be easily separated into a sheet-like substrate material.

  In recent years, flexible substrates (flexible printed wiring boards) have been used in mobile phones, liquid crystal displays, digital cameras, hard disks, and many other electronic devices. Because of its flexibility, it is indispensable for use in hinges and movable parts, or for compactly storing a wiring board in equipment. However, due to its flexibility, when a flexible substrate is manufactured by a conveying means using a sheet-like flexible substrate material, conveyance troubles such as winding, dropping, and skewing frequently occur. The sheet-like substrate material cannot be transferred by a simple transfer mechanism as can be seen.

  A typical configuration of the flexible substrate material is a so-called three-layer material of insulating film / adhesive layer / copper foil such as polyimide or liquid crystal polymer (in the case of double-sided board, copper foil / adhesive layer / insulating film / adhesive layer). / Copper foil) is the mainstream, but in recent years two-layer materials without an adhesive layer are increasing, but the flexibility becomes higher and the conveyance trouble is more serious than the three-layer material. Further, the thickness of copper foil and insulating film is expected to become thinner in the future, and roll-to-roll processing is preferable in order to ensure transportability.

  However, roll-to-roll processing requires enormous capital investment, so some processes are processed with sheet-like materials, and then sheet-like materials are connected and processed into roll-like materials. There is a request. For example, laser drilling a sheet-like material, then plating it into a roll-like material, laminating or applying a photoresist, and after pattern exposure, it is separated into a sheet-like material after alkali development, etching and resist stripping steps Flow is a typical workflow. In this flow, when electrolytic plating is performed, it is necessary to electrically connect between the sheet-like substrate materials using a jig or using a conductive tape (for example, a metal tape). In addition, because of excellent uniformity, a photosensitive resin composition having an ion-forming group may be electrodeposited. In this case as well, a jig is used or a conductive tape is used to conduct a conductive material between sheet-like substrate materials. Need to connect. The attachment and detachment of the jig is a very time-consuming operation, which is not preferable in terms of work efficiency. Further, when the conductive tape is separated into a sheet-like material, a process of cutting or peeling the tape is required. At that time, in the case of the flexible substrate material, there are problems such as deformation, elongation, tearing, or dust generation.

In Patent Documents 1 and 2, a substrate connecting tape in which a layer that dissolves in an etching solution, a layer that dissolves in a resist removal solution and has etching resistance, and a layer that dissolves in a resist removal solution and has adhesion are laminated In addition, a technique is disclosed that eliminates the etching non-uniformity phenomenon by connecting a substrate with a substrate connecting tape in which a layer that dissolves or swells in an etching solution and a layer that dissolves or swells in a resist removal solution are laminated. At the same time, the transportability in the alkali development / etching process is greatly improved, and the adverse effects such as deformation, elongation, tearing, and dust generation when separated into a sheet-like material are also improved. However, when the sheet-like substrate material is connected with these substrate-connecting tapes, the sheet-like substrate material is insulated, and a new technique for conducting conductive connection has been demanded.
JP 2004-43848 A JP 2003-342543 A

  An object of the present invention is to propose a method for manufacturing a printed circuit board which can be electrically connected to a sheet-like substrate material, and can be subjected to electrolytic plating, electrodeposition, etc., and then can be easily separated into a sheet-like substrate material.

  As a result of investigations by the inventors, at least a metal layer that dissolves in the etching solution, a layer that dissolves in the resist removal solution and has etching resistance, and a layer that dissolves in the resist removal solution and has adhesiveness are laminated. In the printed circuit board manufacturing method in which the edges in the transport direction of the sheet-like substrate material are connected to each other with the board-connecting tape, and the substrate-connecting tape is 150 to 400 ° C. from the substrate-connecting tape surface toward the sheet-like substrate material. It has been found that the above-mentioned problems can be solved by a method for producing a printed circuit board, characterized in that a sheet-like substrate material is electrically connected by pressurization with a terminal.

  Alternatively, the edges in the transport direction of the sheet-like substrate material are connected to each other with a substrate connecting tape in which at least a metal layer that dissolves in the etching solution and a layer that dissolves in the resist removal solution and has adhesive properties are laminated. In the manufacturing method of the printed circuit board to convey, manufacturing of the printed circuit board characterized by carrying out the conductive connection between the sheet-like board | substrate materials by pressing with the terminal of 150-400 degreeC toward the sheet-like board | substrate material from the board | substrate connection tape surface It has been found that the above problems can be solved by a method.

  As a preferred embodiment, the present inventors have found that the above-mentioned problems can be solved by a method for producing a printed circuit board, in which the substrate connection tape is dissolved and removed in an etching step and a resist removal step and separated into a sheet-like substrate material.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the printed circuit board which can carry out the electroconductive connection of the sheet-like board | substrate material, electroplating, electrodeposition etc., and can be easily isolate | separated into a sheet-like board | substrate material after that can be provided.

  The best mode for carrying out the present invention will be described in detail below. In the present invention, the metal layer dissolved in the etching solution of the substrate connecting tape is made of a metal material such as copper, silver, aluminum, stainless steel, nichrome, iron and tungsten, copper, iron, chromium, zinc, tin or the like. An alloy or the like can be used. For example, if it is a printed circuit board for forming a copper wiring circuit, it is easier to use the same metal and solubility as the circuit, so copper can be used suitably. The thickness of the metal layer dissolved in the etching solution is 1 to 200 μm, preferably 5 to 50 μm.

  In the present invention, the layer that dissolves in the resist removal solution and has etching resistance has at least a property of not dissolving or swelling in the etching solution, and has a strength that can withstand those spray pressures. All of this layer is removed in the middle of the resist removal section. Examples of the layer that dissolves in such a resist removing solution and has etching resistance include, for example, a dry film resist film obtained by curing a photosensitive layer from which a mylar film and a protective film are peeled off by heat or ultraviolet irradiation, or a liquid photoresist. And a film cured by heat or ultraviolet irradiation after drying. In addition, films and polyvinyls having a carboxylic acid group, a phenolic hydroxyl group, a sulfonic acid group, a sulfonamide group, a sulfonimide group, and a phosphonic acid group, which are soluble in a strong alkali made of acrylic resin, epoxy resin, urethane resin, phenol resin, etc. Alcohol etc. are mentioned. The thickness of the layer dissolved in the resist removing solution and having etching resistance is 1 to 200 μm, preferably 5 to 100 μm.

  In the present invention, the layer that is dissolved in the resist removing solution and has adhesiveness plays a role of adhering the substrate connecting tape and the substrate, and is quickly removed by the resist removing unit when etching is no longer necessary. The If necessary, the adhesiveness may be increased by heating. Examples of such a layer include an adhesive resin mainly composed of an acrylic resin, an epoxy resin, a urethane resin, a phenol resin, and the like. These adhesive resins contain a monomer having a carboxylic acid group, a phenolic hydroxyl group, a sulfonic acid group, a sulfonamide group, a sulfonimide group, or a phosphonic acid group because they need to be dissolved or swelled in the resist removing solution. Specific examples of the adhesive resin include styrene / maleic acid monoalkyl ester copolymer, methacrylic acid / methacrylic acid ester copolymer, styrene / methacrylic acid / methacrylic acid ester copolymer, acrylic acid / methacrylic acid ester copolymer. , Methacrylic acid / methacrylic acid ester / acrylic acid ester copolymer, styrene / methacrylic acid / acrylic acid ester copolymer, styrene / acrylic acid / methacrylic acid ester copolymer, vinyl acetate / crotonic acid copolymer, vinyl acetate Styrene, acrylic acid ester, methacrylic acid ester, vinyl acetate, vinyl benzoate, etc., and carboxylic acid-containing monomers such as / crotonic acid / methacrylic acid ester copolymer, vinyl benzoate / acrylic acid / methacrylic acid ester copolymer And a copolymer thereof. Moreover, you may contain plasticizers, such as polyethyleneglycol, polypropylene glycol, diethyl phthalate, o-toluenesulfonic acid amide, p-toluenesulfonic acid amide, tributyl citrate, triethyl citrate, acetyl triethyl citrate. Moreover, in order to improve visibility, you may contain dye and a pigment. Moreover, you may use the dry film resist which consists of an uncured photosensitive layer which peeled the mylar film and the protective film as a layer which melt | dissolves in a resist removal liquid and has adhesiveness. As a general resist film, for example, Liston from DuPont MRC Dry Film Co., Ltd., Fotec from Hitachi Chemical Co., Ltd., Sunfort from Asahi Kasei Electronics Co., Ltd. can be used. The thickness of the layer that dissolves in the resist removal solution and has adhesiveness is 1 to 200 μm, preferably 5 to 100 μm.

  The structural example of the board | substrate connection tape in this invention is shown to FIGS. As shown in FIG. 1, the substrate connection is formed by laminating the layer 4 dissolved in the etching solution, the layer 5 dissolved in the resist removing solution and having etching resistance, and the layer 6 dissolved in the resist removing solution and having adhesiveness. Tape 1 and a substrate connecting tape 2 in which a layer 4 that is dissolved in an etching solution and a layer 6 that is dissolved in a resist removing solution and has adhesive properties are laminated as shown in FIG. The layer it has may be composed of a plurality of layers. Moreover, as long as the subject of this invention is solved, the other layer may be contained.

  In this invention, the board | substrate connection tape connects the edge parts of the conveyance direction of sheet-like board | substrate material mutually with a board | substrate connection tape. The tape may be affixed on both sides or only on one side. FIGS. 3 to 4 show a cross-sectional structure of a part in which a sheet-like substrate material is connected to both sides or one side with a substrate connecting tape. FIGS. 3-4 has shown the example which affixed the board | substrate connection tape 1. FIG. Moreover, the example of affixing a tape is shown in FIGS. In the present invention, the edges of the sheet-like substrate material in the carrying direction, that is, the front and rear sides in the carrying direction are connected to each other with a substrate connecting tape. Any attachment method may be used as long as no conveyance failure occurs due to cutting, deformation, twisting, distortion, or the like during conveyance. The sheet-like substrate materials are preferably connected so as not to overlap. In actual production, it is difficult to align the edges without gaps, and it is preferable to connect the sheet-like substrate materials with an interval. The interval varies depending on the length, width, sticking method, adhesion to the material, process, etc. of the tape, and thus cannot be defined unconditionally. Preferably it is 5 mm or less. More preferably, it is 0.5 mm to 3 mm. Any method and apparatus may be used for connecting the sheet-like substrate materials with the substrate connecting tape as long as the materials can be securely connected. For example, the technique described in JP-A-2002-2223057 is used. can do. In FIG. 5, the width of the sheet-like substrate material is longer than the length of the substrate connecting tape 1, but in the present invention, the relationship between the width of the sheet-like substrate material and the length of the substrate connecting tape 1 is not particularly limited. Absent.

  In the present invention, the substrate connecting tape is preferably applied by applying pressure while heating. Since it varies depending on the configuration and components of the substrate connecting tape, the material of the substrate, and the like, the affixing conditions cannot be specified in general, but the temperature is 40 to 140 ° C. and the pressure is preferably 0.1 to 0.6 MPa.

  In the present invention, the metal layer dissolved in the etching solution of the substrate connecting tape is completely removed in the middle of the etching part, dissolved in the resist removing solution and having etching resistance, and dissolved in the resist removing solution and adhered. The layer having the property is completely removed in the middle of the resist removing portion, so that the substance constituting the substrate connecting tape is completely removed in the resist removing step and separated into the sheet-like substrate material. Therefore, a simple transport mechanism can be used in the process before the resist removal process, and if the transportability of only the resist removal process is improved, a flexible material can be transported stably and a printed circuit board can be manufactured. Can do.

  In the present invention, the plurality of sheet-like substrate materials are conductively connected by applying pressure at a terminal of 150 to 400 ° C. from the substrate connecting tape surface toward the sheet-like substrate material. The electrical performance (for example, electrical resistance) of the conductive connection required by the process used varies, but in the present invention, the conductive connection means that the electrical resistance value between two connected sheet-like materials is 100Ω. It refers to the following state. Preferably it is 10Ω or less. More preferably, it is 5Ω or less.

  Since it differs depending on the configuration and material of the substrate connecting tape, the specifications of the sheet-like substrate material, the dimensions, the shape of the terminal, etc., it cannot be specified unconditionally, but as the specific processing conditions for the conductive connection, the terminal at 150 to 400 ° C., It is preferable to apply a load of 0.1N to 10N from the surface of the substrate connecting tape to the sheet-like substrate material for 0.1 to 60 seconds. Preferably, a load of 0.2 N to 5 N is applied to the sheet-shaped substrate material from the surface of the substrate connecting tape at a terminal of 200 to 350 ° C. over 0.1 to 30 seconds. Preferably, a load of 0.1N to 5N is applied to the sheet-like substrate material from the surface of the substrate connecting tape at a terminal of 200 to 350 ° C. over 0.1 to 10 seconds. According to the present invention, the resin layer constituting the substrate connecting tape is deformed by simultaneous heating and pressurizing, and the metal layer constituting the substrate connecting tape forms the metal on the surface of the sheet-like substrate material (copper wiring circuit) The present inventors have found that if the printed circuit board is made into contact with copper) to conduct electricity, and then radiates heat, the resin retains its shape and a conductive connection is obtained. Below the temperature range of the present invention, conduction is not possible, and above the temperature range of the present invention, the shape of the resin constituting the substrate connecting tape is not maintained, and a conductive connection cannot be obtained stably.

  In the present invention, any terminal shape can be used as the terminal to be pressurized at 150 to 400 ° C. Either a terminal that contacts and pressurizes on a spherical surface or a plane, a terminal such as a tip of a needle, or a terminal that contacts and pressurizes linearly can be used. In the present invention, it is preferable that the pressurization for conducting the conductive connection is carried out after the substrate connecting tape is bonded to the sheet-like substrate material and connected or simultaneously. A typical process is shown below. Place the board connection tape affixing portion of the sheet-like substrate material 3 to which the board connection tape 1 is attached and connected on a hard plate such as metal (for example, stainless steel) or ceramic, and a metal layer on the surface of the board connection tape While measuring the electrical resistance between the substrate and the metal on the surface of the sheet-like substrate material, pressure is applied as shown in FIG. When the resistance is reduced by pressurization, the terminal 7 is pulled away. It is confirmed that the continuity is maintained even when the terminal 7 is released. If the adjacent sheet-like substrate materials connected are pressed similarly from the surface of the same substrate connecting tape as shown in FIG. 9 and conduction is obtained in the same manner, the two sheet-like substrate materials are conductively connected. Become. There may be one or more places to pressurize, and any number of places.

  When it is necessary to conductively connect both surfaces of the sheet-like substrate material, the conductive connection can be made by applying a substrate connecting tape on both surfaces and pressurizing with both terminals at 150 to 400 ° C.

  A dry film resist (resin film thickness 25 μm) from which the protective film was peeled off was attached to an 18 μm copper foil, and the resist film was cured by irradiating with ultraviolet rays to peel off the mylar film. Next, the dry film resist (resin film thickness 25 μm) from which the protective film was peeled off was pasted on the cured resist film surface. This was cut into a width of 15 mm and a length of 50 m to produce a substrate connecting tape A.

  The board-connecting tape A having a length of 230 mm is applied to a mylar film so that the distance between the long sides (250 mm side) of the sheet-like substrate material (150 mm × 250 mm, single-sided copper foil thickness 12 μm, polyimide base material thickness 25 μm) is about 2 mm. Then, as shown in FIG. 5, the sheet-like substrate material is connected to the edge portion of the flexible substrate material by pressing with a hot roll heated to 110 ° C. to obtain a connection substrate a. It was. The substrate connection tape A was attached to only one side as shown in FIG.

Place the connecting substrate a on a stainless steel plate and measure the electrical resistance between the metal layer on the surface of the substrate connecting tape and the metal on the surface of the sheet-like substrate material using an electrometer 617 model manufactured by Keithley Instruments Co., Ltd. However, FX-951 replacement iron tip T12-BC3 3BC type made by Hakumitsu Co., Ltd. is used as a terminal for pressurization, the temperature of the tip is changed as shown in Table 1, and a 1N load is applied to the tape for board connection. Pressure was applied from the surface toward the sheet-like substrate material as shown in FIG. 8, and the terminals were separated 3 seconds after the electrical resistance reached 1Ω. Similarly, pressure was applied from the surface of the substrate connecting tape toward the adjacent sheet-like substrate material as shown in FIG. 9, and the terminals were separated 3 seconds after the electrical resistance reached 1Ω. Then, using an electrometer 617 model manufactured by Keithley Instruments Co., Ltd., the electrical resistance between adjacent sheet-like substrate materials was measured at an applied voltage of 1 V, and classified into the following three levels. In addition, the temperature of the front-end | tip part of a terminal was measured with the tip thermometer 191 by a white light company.
Less than 1: 1Ω 2: 1Ω or more and less than 1MΩ 3: 1MΩ or more The same operation was performed five times for each temperature. The results are shown in Table 1. Moreover, in Table 1, the ratio in which the electric resistance became 1Ω or less among the five trials was expressed as a fraction in terms of conductive connection ratio.

  According to the present invention, it can be seen that the sheet-like substrate material can be conductively connected. Although there are some cases where conductive connection is not possible due to the evaluation by applying pressure at only one location, it is confirmed that the press connection at multiple locations allows almost complete conductive connection without failure and is a very useful technology. It was done. When electrolytic plating was performed on the connecting substrate a conductively connected with a terminal at 300 ° C., it was possible to deposit the same electrolytic copper as in the case of electrolytic plating by being electrically conducted with a jig. In addition, the connecting substrate a conductively connected with a terminal at 300 ° C. is separated into a sheet-like substrate material by etching and resist stripping process, and the pressurization portion is observed with a 100 times magnifier, and a minute damaged portion of about 100 microns is confirmed. It was done. The minute damage at the end of the sheet-like substrate material has no problem in practice.

Sectional drawing of the tape for board | substrate connection. Sectional drawing of the tape for board | substrate connection. Sectional drawing of the part which connected the sheet-like board | substrate material with the tape for board | substrate connection on both surfaces. Sectional drawing of the part which connected the sheet-like board | substrate material with the tape for board | substrate connection on the single side | surface. The top view of the board | substrate connected with the tape for board | substrate connection. The top view of the board | substrate connected with the tape for board | substrate connection. The top view of the board | substrate connected with the tape for board | substrate connection. Sectional drawing at the time of pressurization with a terminal toward the sheet-like board | substrate from the tape surface for board | substrate connection. Sectional drawing at the time of pressurization with a terminal toward the sheet-like board | substrate from the tape surface for board | substrate connection.

Explanation of symbols

1 Tape for board connection 1
2 Board connection tape 2
DESCRIPTION OF SYMBOLS 3 Sheet-like board | substrate material 4 Layer which melt | dissolves in etching liquid 5 Layer which melt | dissolves in resist removal liquid, and has etching resistance 6 Layer which melt | dissolves in resist removal liquid, and has adhesiveness 7 Terminal for pressurization

Claims (3)

  At least a metal layer that dissolves in an etching solution, a layer that dissolves in a resist removal solution and has etching resistance, and a substrate connection tape in which a layer that dissolves in a resist removal solution and has adhesive properties is laminated into a sheet shape In a printed circuit board manufacturing method in which edges in the conveyance direction of a substrate material are connected to each other and conveyed, the sheet-like substrate material is pressed by a terminal at 150 to 400 ° C. from the surface of the substrate connection tape toward the sheet-like substrate material. A method of manufacturing a printed circuit board, characterized in that conductive connection is made between them.   At least the metal layer that dissolves in the etching solution and the adhesive layer that dissolves in the resist removal solution and is laminated are connected to each other in the conveying direction of the sheet-like substrate material. In a printed board manufacturing method, the printed board manufacturing method is characterized in that the sheet-like board material is conductively connected by pressurizing from the surface of the board-connecting tape toward the sheet-like board material with a terminal of 150 to 400 ° C. .   3. The method for producing a printed circuit board according to claim 1, wherein the substrate connecting tape is dissolved and removed in an etching step and a resist removing step to separate into a sheet-like substrate material.

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