JP4784456B2 - Printed wiring board manufacturing method and printed wiring board - Google Patents

Description

The present invention relates to a manufacturing how and print wiring board of the printed wiring board.

  In recent years, in the electronics industry, development of multifunction devices with high reliability has been rapidly progressing, and with the emergence of high functionality and high density elements, high reliability, multifunction, and light weight have been developed. There is an increasing demand for thin, small devices. As a result, the development of new element mounting technologies is becoming more important every day, and development is progressing as important issues especially in miniaturization and multilayering of semiconductor packages. Furthermore, in addition to the various performances described above, the manufacturing cost becomes an important issue.

  Currently, solder bonding is used for electrical connection between a semiconductor package and a semiconductor chip or between a semiconductor package and a printed wiring board. The connection reliability of the solder joint terminal part of these semiconductor packages or printed wiring boards is very important from the viewpoint of the reliability of electronic components. To meet these requirements, the surface of the solder joint terminal part is currently plated with nickel gold It is generally performed.

  Specifically, an insulating resin such as solder resist is formed in addition to the outermost solder joint terminal portion of the semiconductor package or printed wiring board, and the solder joint terminal portion is further subjected to pretreatment such as degreasing, pickling and chemical polishing. After that, if a circuit that can energize all of the exposed solder joint terminals can be formed in advance, electrolytic nickel plating and electrolytic gold plating are applied, and the electrically energized circuit cannot be routed and is electrically isolated solder joint terminal When the portion exists, electroless nickel plating and electroless gold plating are applied.

  The semiconductor package or printed wiring board is secured and mounted / fixed by applying an electrical paste to the solder joint terminal portion or mounting a solder ball, and then mounting an electronic element to melt the solder. Electronic parts or products are manufactured. Here, since the surface of the solder joint terminal portion is likely to be oxidized due to various thermal histories in the assembly process, gold plating is applied to ensure the connection reliability.

  For example, in the case of a semiconductor package, a pre-bake process (125 ° C., 2 h) before mounting an IC chip, a thermosetting process (110 ° C., 30 minutes) when fixing with a thermosetting resin after mounting an IC chip, a wire bonding process ( 110 ° C., 30 seconds), or flip-chip mounting, the primary mounting reflow process (peak temperature 240 ° C. for about several minutes), the mold resin forming step made of epoxy resin on the chip (175 ° C., 90 seconds), and The thermosetting process (175 ° C., 6 h) and a wide variety of severe thermal histories are received.

  When the solder joint terminal part is made of a metal other than copper, nickel, or gold, the metal surface (surface of the solder joint terminal part) is oxidized by these thermal histories, so sufficient solder jointability and solder wettability It is difficult to ensure. Furthermore, since the oxidation of the solder joint terminal portion occurs during the manufacturing process of the semiconductor package or the printed circuit board, during the shipping inspection, during inventory, and during the shipment, the anti-oxidation measures for the solder joint terminal portion are very important. In order to solve these problems, it is inevitable to use expensive and expensive gold among metals, such as precious metal material costs, multiple wet treatment costs such as pretreatment and plating, and liquid management costs, etc. At present, the manufacturing cost is very high.

Therefore, for example, as disclosed in Patent Documents 1 and 2, a technique has been proposed in which an organic film that does not hinder solder jointability is formed on the solder joint terminal portion to protect the metal surface from oxidation. These form an organic film of a benzotriazole compound or a benzimidazole compound that selectively adsorbs on the copper surface to prevent oxidation, thereby ensuring solder jointability.
JP-A-6-81161 Japanese Patent Laid-Open No. 2000-200964

However, the organic film of the above-described antioxidant benzotriazole compound or benzimidazole compound exhibits good solder bonding properties when the thermal history of the assembly process is not applied, but is severe in the mold resin curing process of the semiconductor package, etc. Cannot withstand the heat history.
Further, the insulating resin layer such as a solder resist provided in the outermost layer is exposed to various wet treatments when plating the surface of the solder joint terminal portion. That is, since it is subjected to stress of an acid or alkaline high temperature pretreatment liquid or plating solution, there is a concern that the electrical reliability of the semiconductor package or the printed wiring board is inevitably lowered. Therefore, in order to select a solder resist that can withstand reliability, it is essential to conduct a long-term electrical reliability test, and there is a problem in that it is inevitable to select a solder resist with a high cost and a high quality.

  Due to the above problems, at present, it is necessary to take anti-oxidation measures by gold plating, which not only complicates the manufacturing process but also significantly increases the material cost, liquid management cost, and the like.

This invention aims to provide a was made in view of the above, excellent in easy and inexpensive and productivity, production how the solder joint excellent in the printed wiring board and the print circuit board It is said.

The present inventors have, the problem investigations for solving proposes a manufacturing side Ho及 beauty printed wiring board of the printed wiring board of the present invention.

The invention according to claim 1 is a laminated structure of a conductor layer and an insulating resin, and is disposed on the outermost layer in a method for manufacturing a printed wiring board in which a solder joint terminal portion is formed on the conductor layer disposed on the outermost layer. A solder resist is formed on the conductor layer so that the solder connection terminal portion is exposed, surrounds the periphery of the solder joint terminal portion, and is higher than the solder joint terminal portion. , on of the solder resist, the not covered before Symbol solder bonding terminal portions, and so as not to contact directly with the solder joint terminal portion, characterized in that a protective sheet is disposed by thermocompression bonding or thermal roller lamination It is a manufacturing method of a printed wiring board.

  According to this printed wiring board manufacturing method, the solder joint terminal portion of the printed wiring board is disposed so as to be covered with the protective sheet, so that the manufacturing process, the shipping history, and the thermal history of the assembly process of the electronic component or electronic device are performed. Therefore, it is possible to prevent the surface of the solder joint terminal portion from being oxidized, and to ensure good solder joint property and solder wettability. As a result, significant material costs and liquid management costs due to the pretreatment process and plating process that have been conventionally performed can be reduced.

Furthermore, the parts other than the solder joint terminal part are protected by a resin insulating layer such as a solder resist, but since these parts are formed before the plating process of the solder joint terminal part, they are hot and have strong acid and alkaline properties. It can be expected that stress of immersion in the plating pretreatment bath and the plating bath can be avoided and a highly reliable printed wiring board can be manufactured.
Further, since the protective sheet is disposed by thermocompression bonding or a heat roller laminating method, only a laminator or the like is added to the current manufacturing process of the printed wiring board, and a large apparatus introduction cost is not required.

The invention according to claim 2 is a printed wiring board manufactured by the method for manufacturing a printed wiring board according to claim 1, wherein the protective sheet is disposed, and has a laminated structure of a conductor layer and an insulating resin, solder joint terminal portion in the conductive layer disposed on the outermost layer is formed, so that the solder connection terminal portions are exposed, and, so as to surround the periphery of the solder joint terminal portion, and the solder bonding terminals the solder resist is formed to be higher than parts, over the solder resist, the not covered before Symbol solder bonding terminal portions, and so as not to contact directly with the solder joint terminal portion, the protective sheet is disposed It is the printed wiring board characterized by the above-mentioned.

  According to this printed wiring board, since the solder joint terminal portion is protected by the protective sheet, it is possible to prevent the surface of the solder joint terminal portion from being oxidized due to the thermal history of the subsequent process, and good solderability and solder wettability. Can be secured.

The invention according to claim 3, the gap between the solder joint terminal portion and the solder resist and the protective sheet, is printed wiring board according to claim 2, characterized in that the inert gas is filled .
According to the printed wiring board having this configuration, since the inert gas is filled in the gap between the solder resist and the protective sheet, the surface of the solder joint terminal portion can be reliably prevented from being oxidized. In particular, it is effective when the surface area of the solder joint terminal portion is large and the gap becomes large.
As the inert gas, it is desirable to use nitrogen gas or argon gas from the viewpoint of cost.

Invention, according to claim 2 or claim 3, characterized in that said solder bonding terminal portion of the surface between the protective sheet, the flux or OSP layer is formed according to claim 4 Printed wiring board.
According to the printed wiring board having this configuration, since the flux or the water-soluble preflux layer is formed between the surface of the solder joint terminal portion and the protective sheet, the solder joint terminal portion is more effectively prevented from being oxidized. can do.

The invention according to claim 5, between the solder joint terminal portion of the surface and the protective sheet, claim 2, wherein a metal plating layer is formed of any one of claims 4 It is a printed wiring board.
According to the printed wiring board having this configuration, the surface of the solder joint terminal portion is covered with the metal plating layer, and oxidation of the surface of the solder joint terminal portion can be more effectively prevented.

According to the present invention, in the process of manufacturing, shipping, and assembling electronic components and electronic devices, printed circuit boards can be prevented from being thermally oxidized in the solder joint terminal portion, and the solder joint property can be improved. It is possible to reduce the precious metal plating cost, the other chemical solution processing cost, and the manufacturing cost, and it is possible to manufacture a printed wiring board that is easy, inexpensive, excellent in productivity, and excellent in solder jointability.
The printed wiring board of the present invention can be used as a semiconductor package substrate (interbosa) and a mother board on which the semiconductor package is mounted.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 1, the printed wiring board 10 according to the present embodiment has a laminated structure of a conductor layer 11 and an insulating resin 12 constituting an electric circuit.

  The conductor layer 11 is generally made of copper and has a solder joint terminal portion 11A. The conductor layer 11 is formed by forming a resist pattern on the copper foil formed on the insulating resin 12 and etching the conductive layer 11, and forming a resist pattern after forming a thin conductive layer on the insulating resin 12 by electroless plating or sputtering. Then, after the electrolytic plating, the resist pattern is peeled off and the thin conductive layer is etched to form a circuit, and after the resist pattern is formed on the insulating resin 12, the resist pattern is removed after the electroless plating is performed. It is formed by law.

In order to protect the conductor layer 11, a solder resist 13 is applied to the surface of the conductor layer 11 other than the solder joint terminal portion 11A. The conductor layer 11 is protected by filling or laminating a paste-like or dry-film-like insulating resin. That is, the solder resist 13 is provided so as to expose the solder connection terminal portion 11A and surround the periphery of the solder joint terminal portion 11A.
In addition, if it is a thermosetting soldering resist paste, the pattern of the soldering resist 13 can be formed with a screen printing method. If it is a photosensitive solder resist, the pattern of the solder resist 13 can be formed by the photolithographic method.

  Here, since the thickness of the solder resist 13 is thicker than that of the conductor layer 11, there is a gap between the surface of the solder joint terminal portion 11 A to which the solder resist 13 is not applied and the surface of the solder resist 13. Will occur.

A protective sheet 15 with an adhesive material is disposed on the surface of the solder resist 13.
The protective sheet 15 includes an adhesive layer 15 </ b> A and a base material layer 15 </ b> B that are adhesive to the solder resist 13. Note that a separator layer may be provided on the surface of the adhesive layer 15A for the purpose of handling other than the pasting and protecting the adhesive layer 15A. That is, the protective sheet 15 may have a three-layer structure including a base material layer 15B, an adhesive layer 15A, and a separator layer. In this case, when the protective sheet 15 is affixed to the surface of the solder resist 13, the separator layer is previously peeled or laminated while being peeled.

  The base material layer 15B of the protective sheet 15 may be any material that can be wound up. For example, as the thermoplastic resin film, a polyester resin film such as polyethylene terephthalate or polyethylene naphthalate, Polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride, acrylic resin, or the like, or polyamide-based resin, polyimide resin, polyether sulfone, and polyether ketone can be used. The thermosetting resin may be a phenol resin, a melamine resin, an epoxy resin, or a fiber reinforced film thereof, or one filled with an inorganic filler.

Further, the base material layer 15B may be a laminated structure of different resins or a functional film including a gas barrier layer and the like.
Moreover, in order to raise the adhesive force with the adhesion layer 15A, you may perform easy adhesion processes, such as a plasma process, a corona treatment, and a blast process, to the base material layer 15B surface.

  In addition, the thickness of the base material layer 15B is desirably in the range of 20 μm to 200 μm. When the thickness of the base material layer 15B exceeds 200 μm, not only the workability at the time of laminating is bad, but also the handleability when peeling off the protective sheet 15 is remarkably lowered. Furthermore, if the adhesive strength of the adhesive layer 15A is strong and the printed wiring board 10 is extremely thin, the product may be destroyed. On the other hand, if the thickness of the base material layer 15B is less than 20 μm, the base material layer 15B is peeled off from the printed wiring board 10 depending on the material of the base material layer 15B when the strength of the base material layer 15B is weak and the adhesive force of the adhesive layer 15A is strong. Sometimes, the protective sheet 15 may be broken.

  The adhesive layer 15A of the protective sheet 15 may be any adhesive material that can be adhered to the solder resist 13 and peeled off immediately before solder mounting. For example, in the case of a semiconductor package, IC chip die bonding, wire bonding, flip chip mounting If so, any material can be used as long as it can be reflowed after the primary mounting reflow and further after the molding and molding resin thermosetting process. Examples of the adhesive material include an acrylic adhesive and a UV curable adhesive material.

  The thickness of the adhesive layer 15A is desirably in the range of 3 μm to 20 μm. When the thickness of the adhesive layer 15A exceeds 20 μm, the adhesive material is filled in the gap between the solder resist 13 and the solder joint terminal portion 11A on the surface of the printed wiring board 10, and the adhesive material contacts the surface of the solder joint terminal portion 11A. Resulting in. Furthermore, when the protective sheet 15 is peeled off, the adhesive material is transferred to the surface of the solder joint terminal portion 11A, and the solder joint property may be deteriorated. On the other hand, when the thickness of the pressure-sensitive adhesive layer 15A is less than 3 μm, when the protective sheet 15 is laminated, the followability of the pressure-sensitive adhesive layer 15A to the surface of the printed wiring board 10 is reduced, and the adhesive strength is not only reduced. Without any air bubbles.

  Furthermore, the adhesive strength of the adhesive layer 15A of the protective sheet 15 is such that the adhesive strength at normal temperature after being attached on the printed wiring board 10 is in the range of 1.0 to 10 N / 20 mm by the method described in JIS Z 0237. It is desirable. When the said adhesive force is lower than 1.0 N / 20mm, there exists a possibility that it may peel by the handling in the process after sticking the protective sheet 15. FIG. On the other hand, when the adhesive strength exceeds 10 N / 20 mm, the adhesive strength is too strong and it becomes difficult to substantially peel off, and productivity is lowered.

  Here, in order to dispose the protective sheet 15 on the surface of the solder resist 13, roll lamination by thermocompression bonding or thermocompression bonding of a rubber roll is used. This method is optimal and simple as a laminating method in which the solder joint terminal portion 11A and the adhesive material portion of the protective sheet 15 do not directly contact each other. In addition, when laminating by a method other than thermocompression bonding or roll laminating, for example, vacuum pressure bonding, the adhesive material of the solder joint terminal portion 11A and the protective sheet 15 are in direct contact, and the adhesive material is caused by the thermal history of the assembly process of the semiconductor package or the printed wiring board 10. Adheres to the surface of the solder joint terminal portion 11A, and the adhesive sheet is transferred to the surface of the solder joint terminal portion 11A when the protective sheet 15 is peeled off at the time of solder joining. Alternatively, it is desirable to use a roll laminate by thermocompression bonding of a rubber roll.

  Further, the inert pressure gas is filled in the gap between the solder resist 13 and the solder joint terminal portion 11A by placing the thermocompression-bonding roll portion in an inert gas atmosphere during lamination. The inert gas is preferably nitrogen gas or argon gas from the viewpoint of cost.

Thus, the printed wiring board 10 in which the protective sheet 15 is disposed on the surface of the solder resist 13 is used for an electronic component such as a semiconductor package.
For example, in the assembly process of a semiconductor package, a die bonding process for fixing and thermosetting the IC chip and the semiconductor package with a thermosetting resin when mounting the IC chip, and a reflow process for primary mounting if wire bonding or flip chip mounting is used. In addition, it undergoes a wide variety of severe thermal histories when forming a mold resin made of epoxy resin on the chip and its thermosetting process. Thereafter, the protective sheet 15 is peeled off and a solder ball is mounted on the solder bonding terminal portion 11A, or solder is formed on the solder bonding terminal portion 11A by a method of applying a solder paste by a screen printing method and mounted on an electronic device. To do.

  According to the printed wiring board 10 according to the present embodiment, by protecting the solder joint terminal portion 11A of the printed wiring board 10 with the protective sheet 15, the manufacturing process, shipping history, and heat of the assembly process of electronic components and electronic devices are performed. Oxidation of the metal surface of the solder joint terminal portion 11A due to the history can be prevented, and good solder joint property and solder wettability can be ensured.

Furthermore, since the inert gas is filled in the gap between the solder resist 13 and the solder joint terminal portion 11A, oxidation of the solder joint terminal portion 11A can be further reliably prevented.
Thus, since the oxidation of the solder joint end portion 11A is prevented, there is no need to take an anti-oxidation measure by gold plating as in the prior art, and the printed wiring board 10 can be provided at a low cost.

  Further, since the protective sheet 15 is disposed on the solder resist 13 by using roll lamination by thermocompression bonding or rubber roll thermocompression bonding, the production apparatus to be used is only a laminator. Management costs and chemical production costs can be greatly reduced. Furthermore, the apparatus introduction cost can be suppressed.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.
For example, the surface of the conductor layer 11 may be subjected to different metal plating. For example, nickel plating, tin plating, silver plating and the like are listed here as an example. You may use these according to a use.

  Further, flux may be applied in advance to the surface of the solder joint terminal portion 11A. Examples of the flux to be applied include rosin flux, halogen activation flux, and non-rosin flux such as organic acid. Examples of a method of applying these only to the solder joint terminal portion 11A include a screen printing method or a method of printing after alignment through a metal mask, a dispenser method, an ink jet method, and the like. Further, even if the surface treatment of the solder joint terminal portion 11A is performed with a water-soluble preflux composed of a benzotriazole compound or a benzimidazole compound, the solder joint terminal portion 11A is further effectively prevented from being oxidized. Since these can be selectively applied to the solder joint terminal portion 11A simply by immersing them in an aqueous solution of the above compound, they are simple and effective.

  Furthermore, the printed wiring board according to the present embodiment can be used as a semiconductor package substrate (interbosa) for mounting a semiconductor package or a mother board for mounting a semiconductor package.

  Below, the result of having evaluated the Example which is a printed wiring board of this invention, and a comparative example is demonstrated, respectively.

[Example 1]
(1) Creation of electronic parts for evaluation A double-sided copper-clad laminate with a copper foil thickness of 18 μm and a core material thickness of 0.3 mm is prepared, and a through hole is formed at a desired location with a laser processing machine. Plating was performed and the copper foil on both sides was electrically connected. The through hole portion of the through hole plating was filled with a hole filling resin by a printing method and baked. After polishing the surface, apply dry film resist on both sides, align the through holes of the alignment mark provided in advance on the copper clad laminate and the alignment mark provided on the glass plate, and then place the copper clad laminate from both sides. It is made to adhere so that it may be pinched | interposed with a glass plate, and it exposes through a glass plate. Subsequently, a dry film resist pattern was formed on both copper foil surfaces by developing. By spray-etching ferric chloride from both sides, a flip chip mounting bump is formed on one side, a solder bonding bump for secondary mounting and a copper circuit that electrically connects them are formed on the other side. did. Subsequently, a photosensitive solder resist was applied so as to have a thickness of 30 μm on both sides, followed by patterning so as to expose the flip chip bump and the solder bonding bump, thereby forming a solder resist pattern. In this way, 2 metal BGA was produced.

Subsequently, a protective sheet was laminated on the solder bonding bumps and the flip chip bumps using a roll laminator. The protective sheet uses 7μm thick acrylic resin for the adhesive layer, 125μm PEN film for the base layer, and thermocompression-bonded at a lamination temperature of 120 ° C to protect the two metal BGA on both sides The printed wiring board which is a present Example was created by affixing.
Subsequently, after pre-baking the printed wiring board at 125 ° C. for 2 hours, the protective sheet on the flip chip bump side is peeled off, a solder paste is formed on the flip bump by screen printing, and the IC chip is mounted on the alignment. At the peak temperature of 240 ° C., reflow and underfill filling were performed to complete the primary mounting. Further, the two metal BGAs were placed between the mold dies, and transfer molding was performed on the chip mounting, and the IC chip was covered with the mold resin. Later, post-curing was performed at 180 ° C. for 5 hours. After that, the solder ball surface protective sheet is peeled off and the flux is applied. Then, a lead-free solder ball with a diameter of 0.35 μm is mounted and reflowed to create an electronic component with the solder ball mounted on the ball surface, followed by flux cleaning. It was.

(2) Creation of printed wiring board for solder wettability evaluation Separately from the above-described electronic component creation, a printed wiring board for solder wettability evaluation was created. A copper-clad laminate having a solder resist pattern with a width of 0.4 mm and a length of 5 mm formed under the same material and conditions as the above-described evaluation semiconductor device was prepared, a protective sheet was laminated thereon, and the same as described above. A printed wiring board for solder wettability evaluation was created by applying a thermal history. Similarly, after applying a flux to the slit pattern in which copper is exposed on this printed wiring board, a solder ball of 0.35 mm is mounted at the center of the slit pattern, and solder reflow is performed to measure solder wettability.

(3) Evaluation Method The solder joint strength of the semiconductor device on which the solder balls prepared as described above are mounted was measured by a solder share test. The solder wettability was evaluated using a printed wiring board for solder wettability evaluation. The length of the slit in the longitudinal direction of the solder after reflow is m, the solder ball diameter is d,
Solder wettability% = wetting spread length / solder ball diameter × 100 (%).

[Example 2]
The method of producing the evaluation electronic component and the evaluation printed wiring board was exactly the same as the method of Example 1, but the thermocompression-bonding roll was laminated in a nitrogen atmosphere when the protective sheet was laminated. These were evaluated in the same manner as in Example 1.

[Example 3]
The method for producing the evaluation electronic component and the evaluation printed wiring board is exactly the same as the method of Example 1, but before laminating the protective sheet, it is water-soluble at 50 ° C. on the copper surface of the flip chip bump and the solder bonding bump. It was immersed in a preflux bath for 3 minutes, coated with a preflux film, and dried at 70 ° C. for 10 minutes. Thereafter, a protective sheet was laminated in the same manner as in Example 1. These were evaluated in the same manner as in Example 1.

[Example 4]
The method for producing the evaluation electronic component and the evaluation printed wiring board is exactly the same as the method of Example 1, but before laminating the protective sheet, an electrolytic nickel plating layer is formed on the copper surface of the flip chip bump and the solder bonding bump. Formed. Thereafter, a protective sheet was laminated in the same manner as in Example 1. These were evaluated in the same manner as in Example 1.

[Example 5]
(1) Creation of 2-metal BGA for wire bonding mounting The 2-metal BGA of Example 5 was created in the same manner as in Example 1. In this example, a wire bonding pad was formed on the conductor layer on the chip mounting side, and a solder bonding bump was formed on the opposite surface. Similarly, a solder resist pattern was formed so as to expose the bonding pad portion and the solder joint bump portion of the ball mount portion. The protective sheet was thermocompression bonded only to the ball mount surface by a roll laminator at a laminating temperature of 120 ° C. The protective sheet uses a UV-curable acrylic adhesive material with a thickness of 5 μm for the adhesive layer, and a PET film with a thickness of 125 μm for the base material layer, and after the lamination, through the PET film that is the base material layer of the protective film The adhesive layer was UV cured. Subsequently, nickel-gold plating was performed on the bonding pad portion of the two-metal BGA provided with a protective sheet. Subsequently, after chip mounting and thermosetting the resin for die bonding, the chip and BGA were connected by wire bonding using a gold wire. Further, the two metal BGAs were placed between the mold dies, and transfer molding was performed on the chip mounting, and the IC chip was covered with the mold resin. Thereafter, post-curing was performed at 180 ° C. for 5 hours, the protective sheet was peeled off, flux was applied to the solder joint bumps, the solder balls were mounted and reflowed to connect the solder balls.
A printed wiring board for evaluating solder wettability was prepared under the same material and under the same conditions as in Example 1. These were evaluated in the same manner as in Example 1.

[Comparative Example 1]
An evaluation electronic component and an evaluation printed wiring board, which are the same as the method for producing an electronic component of Example 1 and the method for producing a printed wiring board for solder wettability evaluation, except that the protective sheet is not laminated. These were evaluated in the same manner as in Example 1.

[Comparative Example 2]
The production of the 2-metal BGA was performed in the same manner as in Example 1. Electrolytic nickel plating was formed on the flip chip bumps and solder bonding bumps at 2 μm and electrolytic gold plating was formed at 0.03 μm. A protective sheet was not used. The printed wiring board for solder wettability evaluation was similarly plated with nickel and no protective sheet was used. These were evaluated in the same manner as in Example 1.

  The evaluation results of Examples and Comparative Examples of the present invention are shown in Table 1.

  Examples 1 to 5 of the present invention exhibited solder joint property and wettability equivalent to or higher than those of Comparative Example 2 in which the solder joint terminal portion was plated with nickel gold. Thus, it was confirmed that it is not necessary to perform a nickel-gold plating step, and it is possible to provide a printed wiring board that is inexpensive and has good solderability by a simple process.

It is a fragmentary sectional view of the printed wiring board which is an embodiment of the present invention. It is sectional drawing of a protection sheet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Printed wiring board 11 Conductor layer 11A Solder joint terminal part 12 Insulation resin 13 Solder resist 15 Protective sheet 15A Adhesive layer 15B Base material layer

Claims (5)

In the method of manufacturing a printed wiring board having a laminated structure of a conductor layer and an insulating resin, and a solder joint terminal portion formed on the conductor layer disposed in the outermost layer,
On the conductor layer disposed on the outermost layer, the solder connection terminal portion is exposed, the periphery of the solder joint terminal portion is surrounded, and the height is higher than the solder joint terminal portion. Form a solder resist,
Over the solder resist, pre SL have covered the solder joint terminal portion, and so as not to contact directly with the solder joint terminal portion, printing, characterized in that a protective sheet is disposed by thermocompression bonding or thermal roller lamination A method for manufacturing a wiring board. A printed wiring board manufactured by the method for manufacturing a printed wiring board according to claim 1, wherein the protective sheet is disposed,
It is a laminated structure of a conductor layer and an insulating resin, and a solder joint terminal portion is formed on the conductor layer disposed on the outermost layer,
A solder resist is formed so that the solder connection terminal portion is exposed and surrounds the periphery of the solder joint terminal portion, and is higher than the solder joint terminal portion , on the solder resist , before SL has covered the solder joint terminal portion, and so as not to contact directly with the solder joint terminal portion, the printed wiring board, wherein the protective sheet is disposed. The printed wiring board according to claim 2 , wherein an inert gas is filled in a gap between the solder joint terminal portion, the solder resist, and the protective sheet. Wherein between the solder joint terminal portion of the surface and the protective sheet, the printed wiring board according to claim 2 or claim 3, characterized in that the flux or OSP layer is formed. Wherein between the solder joint terminal portion of the surface and the protective sheet, the printed wiring board according to any one of the preceding claims 2, wherein a metal plating layer is formed.

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