JPH07170030A - Printed circuit board with adhesive layer - Google Patents

Abstract

PURPOSE:To stably maintain interface adhesive state between a separator and an adhesive layer, by arranging an adhesive layer with a separator which is composed of water repellent plastics. CONSTITUTION:A double-sided adhesive tape 3 with a separator whose adhesion to a stainless steel board is 1050g/20mm is stuck on the rear of a printed circuit board main body 1 wherein a polyethylene terephthalate film is printed on a retaining sheet 11. A separator 32 is a polyethylene terephthalate film subjected to silicon peeling process. An electronic component 2 is soldered at 220-230 deg.C. After that, washing is performed by using water based detergent. Since the separator sufficiently withstands the soldering temperature, and exhibits water repellency and water shielding property to water based detergent, the interface adhesive state between the separator and an adhesive layer is stably maintained in splite of heating at the time of soldering, and water permeation to the interface through the separator can be surely prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board with an adhesive layer used for electric circuits of electronic equipment.

[0002]

2. Description of the Related Art Electronic equipment, for example, printed circuit boards used in electric circuits of computers, facsimiles, cameras, calculators, videos, electronic exchanges, various measuring instruments, control equipment, etc. After the components are mounted by soldering, they are arranged and fixed in a predetermined position of the electronic device.

In the above-mentioned soldering, application of flux is indispensable in order to remove the oxide film at the soldering site and to promote the wettability of the solder. In this case, if there is a flux residue after soldering, Since the conductor is eroded due to the activation of the flux and causes a circuit failure, it is necessary to remove the flux residue by washing after soldering.

A screwing system, an adhesive system, or the like is used to fix and dispose the electronic component-mounting printed circuit board on an electronic device. However, unlike the screwing system, the adhesive system acts on a fixed interface. The viscoelasticity of the adhesive allows the adhesive to disperse well at its interface and absorb it, so it has excellent impact resistance and vibration resistance, and can be fixed only by pressurization and has excellent workability. There is.

In this adhesive fixing method, a double-sided adhesive tape with a separator is previously attached to a fixed portion on the back surface of the printed circuit board, the separator is peeled off at the time of fixing the adhesive, and the peeling marks are adhered. It is applied by adhering the surface to a predetermined position of the electronic device, but it is possible to attach the double-sided adhesive tape with a separator to the soldering point before the mounting step by soldering the electronic component described above. It is advantageous in terms of preventing damage and facilitating pressure-bonding of a double-sided adhesive tape with a separator.

[0006]

However, when a double-sided adhesive tape with a separator is attached before the electronic parts are soldered and attached, the double-sided adhesive tape with the attached separator is attached.
Is heated by the molten solder and is exposed to the cleaning liquid when cleaning the flux residue. Depending on the type of separator of the double-sided adhesive tape with separator and the type of cleaning liquid, heating The liquid-tightness of the interface between the separator and the adhesive layer is reduced, and the cleaning liquid permeates into the separator, which inevitably reduces the adhesive strength of the double-sided adhesive tape, ensuring a stable and stable printed circuit board. It is difficult to secure proper adhesive fixation.

Recently, in order to protect the global environment, reduction / abolition of CFCs and chlorinated solvents has been planned on a global scale, and as a cleaning agent for the above-mentioned flux residue, CFC / Trichloroethane can be replaced with an aqueous cleaning agent. Although being promoted, in the present inventors, in a general-purpose paper separator-equipped double-sided adhesive tape, the adhesive strength of the double-sided adhesive tape is remarkably reduced due to the penetration of the water-based detergent into the separator. It is unavoidable, and it has been confirmed that it is difficult to guarantee a reliable and stable adhesive fixation of the printed circuit board.

An object of the present invention is to attach a double-sided adhesive tape with a separator to a predetermined position on the back surface of a printed circuit board in advance, and after mounting an electronic component on the printed circuit board by soldering, separate the printed circuit board. When peeling off the adhesive tape and sticking the adhesive surface of the peeling mark to a predetermined position on the electronic device, attach the double-sided adhesive tape with a separator before soldering the electronic parts and after soldering. An object of the present invention is to provide a printed circuit board with an adhesive layer, which can ensure reliable and stable fixation of the printed circuit board by the double-sided adhesive tape even if the flux residue is washed and removed with an aqueous cleaning agent.

[0009]

In the printed circuit board with an adhesive layer according to the present invention, an adhesive layer with a separator is provided on a fixed portion on the back surface of the printed circuit board body, and an electronic component is soldered to the board body. The printed circuit board with an adhesive layer to be mounted by, after cleaning with an aqueous cleaning agent, the separator of the adhesive layer with the separator is peeled off, and the adhesive surface of the peeled trace is arranged and fixed to an electronic device. The separator is made of a water-repellent plastic, and the separator is
Polyester, polyphenylene sulfide,
Plastic films such as polysulfone, polyethersulfone, polyetherimide, polyetheretherketone, and polyimide are preferably used, and preferably, a plastic film that has been subjected to a release treatment, particularly a polyethylene terephone that has been subjected to a release treatment with a silicon-based polymer. A tarte film is used.

The structure of the present invention will be described below with reference to the drawings. 1 (a) is a plan view showing a flexible printed circuit board according to the present invention, FIG. 1 (b) is a back side view of the same, and FIG. 1 (c) is a cross-section of FIG. 1 (b).
FIG. In (a) to (c) of FIG. 1, 1
Shows a flexible printed circuit board body, which is obtained by etching a copper foil of a copper-clad laminated sheet in which a copper foil is laminated on a heat-resistant plastic film such as a polyimide film or a polyester film into a predetermined circuit pattern by an optical method. is there. Reference numeral 11 is a plastic support film, 12 is a conductor, 120 is a terminal portion, and 13 is an insulating overcoat. Reference numeral 2 is an electronic component such as an IC or LSI mounted by soldering.

Reference numeral 3 is a double-sided adhesive tape with a separator attached to a predetermined fixed portion on the back surface of the printed circuit board body (31 is a double-sided adhesive tape, 32 is a separator), and the separator is a separator. 32 is made of water-repellent plastic, and polyester, polyphenylene sulfide, polysulfone, polyethersulfone, polyetherimide, polyetheretherketone, polyimide films, etc. can be used.
In particular, it is preferable to use those obtained by subjecting the surface of these plastic films to a peeling treatment (for example, a silicone-based polymer or a fluorine-containing polymer-coated one). The double-sided adhesive tape 31 may be a double-sided adhesive tape with an adhesive layer (acrylic, silicone, rubber, etc.) provided on both sides of the support, but both sides without a support and having no substrate It is preferable to use an adhesive tape.

In this double-sided adhesive tape with a separator, the adhesive strength of the double-sided adhesive tape according to JISZ1528 is
For example, 800g / 20mm ~ 1 under stainless steel plate
600g / 20mm, double-sided adhesive tape and separator
Adhesive force with the connector is 4g / 20mm to 50g / 20mm
Is.

In the production of the flexible printed circuit board with the adhesive layer according to the present invention, a double-sided adhesive tape with a separator is attached before mounting the electronic component by soldering. For example, a double-sided adhesive tape with a separator is attached to a predetermined portion of the plastic film surface of the copper-clad laminated sheet, and then a copper foil is formed by etching on a predetermined circuit pattern, or The copper-clad laminated sheet
Etching copper foil on a predetermined circuit pattern, and laminating an insulating overcoat on the etched surface,
Then, a double-sided adhesive tape with a separator can be attached to a predetermined portion of the plastic film surface of the circuit pattern forming sheet.

The mounting of electronic components in the production of the flexible printed circuit board with the adhesive layer according to the present invention is performed manually by using a flow soldering method, a reflow soldering method or a soldering iron, Immediately after this soldering, the flux residue is cleaned and removed by an aqueous cleaning agent. For example, a hole is provided at the soldering point, a disc lead component is inserted into this hole, and the flow method (the bath surface of the solder bath is driven by a rotary pump or gear pump under the bath surface Surface, and the printed circuit board body is run with the electronic component's temporary fixing surface facing downward while in contact with the jet bath surface), and after cooling,
Clean with an aqueous cleaning agent, or apply a cream solder that is a mixture of powder solder and flux to the soldering point by a printing method, and temporarily fix the electronic component by the adhesive force of the printing cream solder, and then , Heating in a heating furnace (electric furnace, infrared furnace, heater block, etc.) to melt the above print cream solder and perform soldering by the reflow method,
After cooling, it can be washed with an aqueous detergent.

In any of the above soldering methods, soldering is usually performed in 2 to 3 seconds. The above-mentioned water-based cleaning agent, that is, an aqueous solution of a surfactant using water as a solvent, may be manufactured by Arakawa Chemical Industry Co., Ltd. under the trade name Pine Alpha, Kao Corporation.
Commercially available products such as the cleansle-trade name manufactured by K.K. can be used, and washing with these water-based detergents is usually performed at a washing liquid temperature of 60.
It is carried out by immersion at 1 ° C for 1 to 5 minutes. After this cleaning, rinse with clean water is performed. This rinsing is usually performed by a pre-rinse and a finish rinsing, and any rinsing can usually be performed by immersing in an ion exchange water tank at a temperature of 30 ° C. for about 1 to 3 minutes. Drying after rinsing can be performed by heating at 80 ° C. for 1 to 2 minutes, for example.

Although the present invention is preferably applied to a flexible printed circuit board, a rigid printed circuit board (phenol / paper base material, epoxy composite, epoxy
It can also be applied to those using a glass cloth substrate or the like as a support plate).

[0017]

Operation: With the double-sided adhesive tape with a separator attached to the main body of the printed circuit board, the electronic components are mounted by soldering and the flux residue is cleaned and removed by the water-based cleaning agent after soldering. Since the above separator sufficiently withstands the soldering temperature, and exhibits water repellency and water impermeability (because of the dense structure without pores) to the water-based cleaning agent, the separator is heated despite the heating during soldering. -The adhesive state of the interface between the adhesive and the adhesive layer is stably maintained, and the permeation of water into the interface through the separator is well prevented.

Therefore, the adhesive strength of the double-sided adhesive tape with the separator is sufficiently set to the initial value (the adhesive strength to the stainless steel plate according to JIS Z1528 is 800 g / 20 mm to 1600 g / 2).
The printed circuit board can be reliably and stably arranged and fixed to a predetermined position of an electronic device with excellent adhesive strength. This is clear from the comparison between the following examples and comparative examples.

[0019]

[Example] Adhesive strength to stainless steel plate (according to JIS Z1528) was 1050 on the back side of a printed circuit board body using a polyethylene terephthalate film as a supporting sheet.
g / 20 mm, a double-sided adhesive tape with a separator, which is a polyethylene terephthalate film whose separator is a silicon peeling treatment, is adhered, and then electronic parts 220 to 2 are attached.
After soldering at 30 ° C., the above-mentioned water-based cleaning agent PINE ALPHA is used for cleaning at 60 ° C. for 3 minutes of immersion time, and further pre-rinsing by immersion in ion-exchanged water at 30 ° C. for 2 minutes, Finishing rinse by dipping in 30 ° C. ion-exchanged water for 2 minutes was sequentially performed, and further dried by aeration with hot air at 80 ° C. for 2 minutes to obtain an example product. Further, a comparative example product was obtained in the same manner as the example product except that silicon peeling kraft paper was used as a separator for this example.

The adhesive strength of the adhesive layer of the double-sided adhesive tape with a separator in these Examples and Comparative Examples (50 samples each) to the stainless steel plate is JISZ1528.
When measured in accordance with
050 g / 20 mm was maintained, but in the comparative example product, it was reduced to 500 g / 20 mm.

In the comparative example, 15 out of 50
Separation of the separator occurred on each sample during washing, and the samples adhered to each other, but no such situation was observed in the example products.

[0022]

In the printed circuit board with the adhesive layer according to the present invention, after the double-sided adhesive tape with the separator is attached as described above, the electronic components are attached by soldering, and the aqueous system after the soldering is performed. The flux residue is cleaned and removed by the cleaning agent, and the adhesive strength of the double-sided adhesive tape with a separator can be maintained at an almost initial value despite heating by soldering heat and immersion in an aqueous cleaning solution.

Therefore, under the use of the water-based cleaning agent which is an alternative cleaning agent for CFC / trichloro, it is possible to ensure the reliable and stable placement and fixing of the electronic device by the adhesive layer, and the separator can be mounted before mounting the electronic parts. The attached double-sided adhesive tape can be safely and easily pressure-bonded, and washing can be smoothly performed without peeling the separator of the double-sided adhesive tape with the attached separator.

[Brief description of drawings]

1A is a plan explanatory view showing an embodiment of the present invention, FIG. 1B is a rear side explanatory view of the same, and FIG. 1C is a cross-sectional view of FIG. FIG.

[Explanation of symbols]

 1 Printed Circuit Board Main Body 11 Plastic Support Sheet 12 Conductor 2 Electronic Component 3 Double-sided Adhesive Tape with Separator 31 Double-sided Adhesive Tape 32 Separator

Claims (4)

[Claims] 1. A printed circuit board main body is provided with an adhesive layer with a separator on a fixed portion on a back surface thereof, an electronic component is mounted on the main body of the board by soldering, and after washing with a water-based cleaning agent, the above-mentioned separator is used. A printed circuit board with an adhesive layer for separating the separator of the attached adhesive layer and disposing and fixing it at a predetermined position of the electronic device on the adhesive surface of the peeled trace, wherein the separator is made of water-repellent plastic. A printed circuit board with an adhesive layer. 2. A printed circuit board with an adhesive layer according to claim 1, wherein the separator is any one of polyester, polyphenylene sulfide, polysulfone, polyethersulfone, polyetherimide, polyetheretherketone and polyimide. 3. The printed circuit board with an adhesive layer according to claim 1, wherein the surface of the separator is subjected to a peeling treatment. 4. The printed circuit board with an adhesive layer according to claim 1, wherein the printed circuit board is flexible.