JP2007035716A

JP2007035716A - Manufacturing method of printed circuit board

Info

Publication number: JP2007035716A
Application number: JP2005213001A
Authority: JP
Inventors: Kanako Nakajima; 加奈子中島; Masatoshi Inaba; 匡俊稲葉; Yoshiharu Unami; 義春宇波
Original assignee: Fujikura Ltd
Current assignee: Fujikura Ltd
Priority date: 2005-07-22
Filing date: 2005-07-22
Publication date: 2007-02-08

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of printed circuit board where connecting particles will not deviate from a through-hole, and continuity failure is less likely to be generated after the pressing process, even when a thin insulating base material is used for the manufacture of FPC. <P>SOLUTION: In the manufacturing method of printed circuit board, a printed circuit board is obtained, by coating a liquid insulating material to at least periphery of through-holes of the insulating base material, to which one or more through-holes are provided or to the internal circumferential surface of the through-holes; allocating connecting particle formed of a conductive material to the through-holes; laminating the conductive members to both surfaces of the insulating base material; pressing the connecting particle by heating and pressurizing these elements; electrically connecting the conductive members of both sides with this connecting particle; and then forming a pattern on the conductive member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、電子機器の内部部品などに用いられるプリント基板の製造方法に関する。 The present invention relates to a method for manufacturing a printed circuit board used for an internal part of an electronic device.

層間導通の一般的な方法として、スルーホールを利用したものがある。図２は、スルーホールを利用して層間導通を行う従来のプリント基板を例示する図であり、この従来のプリント基板は、ポリイミド等からなる絶縁基材１０の両側に銅などからなる導電部材１１を貼り合わせた複合材料に対し、ドリル加工やレーザー加工などの方法で貫通穴１２を穿設し、この貫通穴１２内部にメッキ等で導電部を形成することにより、絶縁基材１０の両側にある導電部材１１間の導通をとっている。 As a general method of interlayer conduction, there is a method using a through hole. FIG. 2 is a diagram illustrating a conventional printed circuit board that conducts interlayer conduction using a through hole. This conventional printed circuit board includes a conductive member 11 made of copper or the like on both sides of an insulating base material 10 made of polyimide or the like. A through-hole 12 is drilled in the composite material bonded together by a method such as drilling or laser processing, and a conductive portion is formed in the through-hole 12 by plating or the like, so that both sides of the insulating base material 10 are formed. Conduction between certain conductive members 11 is taken.

別な方法として、図３に示すように、エッチング等で片側の導電部材１１に開口を形成し、次にエッチングやレーザー加工でその開口下の絶縁基材１０部分を除去し、非貫通穴１３を形成し、この非貫通穴１３へメッキや導電性ペースト充填を行い、絶縁基材１０の両側にある導電部材１１間の導通をとっている。 As another method, as shown in FIG. 3, an opening is formed in the conductive member 11 on one side by etching or the like, and then the insulating base material 10 portion under the opening is removed by etching or laser processing, so that the non-through hole 13 is formed. The non-through holes 13 are plated or filled with a conductive paste to establish conduction between the conductive members 11 on both sides of the insulating substrate 10.

しかし、図２に示すスルーホールや図３に示す非貫通穴を形成し、メッキを施す従来の層間導通方式では、メッキが穴内部だけでなく、銅からなる導電部材の表面にも形成されるため、導電部材の厚さがメッキで増加してしまう。導電部材の厚さは、銅エッチングによるパターン形成に影響を及ぼし、導電部材の銅が厚くなると狭ピッチのパターン形成が困難になる。
また、非貫通穴へ導電性ペーストを充填する場合、両側の導電材料の層間導通は、導電材料と導電性ペーストとの接触により成り立っている。導電性ペーストは導電粒子と樹脂成分とからなり、樹脂成分によって導電ペーストは穴内部へ密着しているが、高温高湿な負荷のかかる環境下では密着性が弱くなり、長期的な導通信頼性に欠ける。 However, in the conventional interlayer conduction method in which the through hole shown in FIG. 2 and the non-through hole shown in FIG. 3 are formed and plated, the plating is formed not only inside the hole but also on the surface of the conductive member made of copper. For this reason, the thickness of the conductive member is increased by plating. The thickness of the conductive member affects the pattern formation by copper etching. When the copper of the conductive member becomes thicker, it becomes difficult to form a narrow pitch pattern.
Further, when the conductive paste is filled into the non-through holes, the interlayer conduction between the conductive materials on both sides is established by the contact between the conductive material and the conductive paste. The conductive paste is composed of conductive particles and resin components, and the conductive paste adheres to the inside of the hole due to the resin component. However, the adhesiveness becomes weak under high temperature and high humidity load environment, and long-term conduction reliability Lack.

一方、特許文献１には、積層基材に少なくとも一つ以上の孔部と、積層基材の両面に導体とを備え、各々の孔部に前記積層基材の厚さより直径が大きい一つの導電性粒子が圧縮状態で埋設され、前記圧縮状態にある導電性粒子により上下の導体と電気的接続されたことを特徴とする両面プリント基板が開示されている。この特許文献１に記載されたプリント基板は、貫通穴に圧縮状態で埋設された導電性粒子により基材両面側の導電部材間を電気的に接続する構成なので、スルーホール内面にメッキを施したり、導電性ペーストを充填することがないので、前述した図２及び図３に示す従来の層間導通方式における問題を回避することができる。
特許第３０５７９２４号公報 On the other hand, Patent Document 1 includes at least one hole portion in a laminated base material and conductors on both sides of the laminated base material, and each hole has one conductive material having a diameter larger than the thickness of the laminated base material. There is disclosed a double-sided printed board characterized in that the conductive particles are embedded in a compressed state and electrically connected to the upper and lower conductors by the conductive particles in the compressed state. Since the printed circuit board described in Patent Document 1 is configured to electrically connect the conductive members on both sides of the base material with conductive particles embedded in a compressed state in the through hole, the inner surface of the through hole can be plated. Since the conductive paste is not filled, the problems in the conventional interlayer conduction method shown in FIGS. 2 and 3 can be avoided.
Japanese Patent No. 3057924

しかしながら、特許文献１記載の従来技術では、絶縁基材の貫通穴内に導電性粒子をセットした状態で両側の導電部材で挟んで圧縮するとともに、絶縁基材も圧縮する構成なので、薄い絶縁基材が用いられるフレキシブルプリント配線板（以下、ＦＰＣと記す。）を作製する場合には、貫通穴に導電性粒子を乗せる際に導電性粒子が動きやすく、プレスの前やプレス中に導電性粒子が動き、貫通穴の位置からずれてしまい、プレスを行っても導電層間の導通不良を生じる可能性がある。 However, in the prior art described in Patent Document 1, since the conductive particles are set in the through-holes of the insulating base material and compressed by sandwiching between the conductive members on both sides, the insulating base material is also compressed. When a flexible printed wiring board (hereinafter referred to as FPC) is used, the conductive particles easily move when the conductive particles are placed in the through holes, and the conductive particles are formed before or during pressing. It moves and deviates from the position of the through hole, and there is a possibility that poor conduction between the conductive layers may occur even if pressing is performed.

本発明は前記事情に鑑みてなされ、ＦＰＣを作製する際に薄い絶縁基材を用いても、接続粒子が貫通穴部からずれることがなく、プレス後に導通不良を生じ難いプリント基板の製造方法の提供を目的とする。 The present invention has been made in view of the above circumstances, and even when a thin insulating base material is used when manufacturing an FPC, the connection particles do not deviate from the through-hole portion, and the printed circuit board manufacturing method is less likely to cause poor conduction after pressing. For the purpose of provision.

前記目的を達成するため、本発明は、１つ以上の貫通穴が設けられた絶縁基材の少なくとも前記貫通穴の周辺又は貫通穴の内周面に液状の絶縁材料を塗布し、次いで導電材料からなる接続粒子を前記貫通穴部に配置し、次いで前記絶縁基材の両面に導電部材を重ね合わせてこれらを加熱、加圧し、前記接続粒子を押し潰し、この接続粒子によって両側の導電部材間を電気的に接続し、次いで導電部材にパターン形成を行いプリント基板を得ることを特徴とするプリント基板の製造方法を提供する。 In order to achieve the above object, the present invention applies a liquid insulating material to at least the periphery of the through hole or the inner peripheral surface of the through hole of an insulating substrate provided with one or more through holes, and then conductive material. The connecting particles are arranged in the through-hole portion, and then the conductive members are superposed on both surfaces of the insulating base material to heat and pressurize them, and the connecting particles are crushed. Are electrically connected, and then a pattern is formed on a conductive member to obtain a printed circuit board.

本発明のプリント基板の製造方法において、接続粒子及び導電部材が銅であり、接続粒子と導電材料とが金属結合により接合されることが好ましい。 In the method for producing a printed board of the present invention, it is preferable that the connection particles and the conductive member are copper, and the connection particles and the conductive material are bonded by metal bonding.

本発明のプリント基板の製造方法において、液状の絶縁材料がポリイミド、ポリエーテルイミド、ポリアミドイミド、液晶ポリマーから選択される熱可塑性樹脂の溶液または前駆体溶液であることが好ましい。 In the method for producing a printed board of the present invention, the liquid insulating material is preferably a thermoplastic resin solution or a precursor solution selected from polyimide, polyetherimide, polyamideimide, and liquid crystal polymer.

本発明のプリント基板の製造方法において、液状の絶縁材料の粘度が１０〜１００ポイズの範囲であることが好ましい。 In the printed circuit board manufacturing method of the present invention, the viscosity of the liquid insulating material is preferably in the range of 10 to 100 poise.

本発明によれば、絶縁基材の貫通穴部に液状の絶縁材料を塗布し接続粒子を固定できるので、ＦＰＣを作製する際に薄い絶縁基材を用いても、接続粒子が貫通穴部からずれることがなく、プレス後に導通不良を生じ難いプリント基板を簡単に製造することができる。 According to the present invention, since the connecting particles can be fixed by applying a liquid insulating material to the through hole portion of the insulating base material, the connecting particles can be removed from the through hole portion even when a thin insulating base material is used when manufacturing the FPC. It is possible to easily manufacture a printed circuit board that is not displaced and hardly causes poor conduction after pressing.

以下、図面を参照して本発明の実施形態を説明する。
図１は、本発明によるプリント基板の製造方法の一実施形態を示す図であり、本実施形態は、本発明の製造方法によってシート状の絶縁基材２０の両面に銅箔などの導電部材２４を貼り合わせ、回路パターンを形成して両面プリント基板を製造する場合を例示している。なお、本発明は本例示に限定されるものではなく、片面プリント基板や複数枚のプリント基板を積層してなる多層プリント基板の製造に適用することもできる。図１中、符号２０は絶縁基材、２１は貫通穴、２２は絶縁材料、２３は接続粒子、２４は導電部材、２５は両面プリント基板用材料である。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing an embodiment of a method for producing a printed circuit board according to the present invention. In the present embodiment, a conductive member 24 such as a copper foil is formed on both surfaces of a sheet-like insulating substrate 20 by the production method of the present invention. Are illustrated, and a circuit pattern is formed to manufacture a double-sided printed circuit board. In addition, this invention is not limited to this illustration, It can also apply to manufacture of the multilayer printed circuit board formed by laminating | stacking a single-sided printed circuit board or several printed circuit boards. In FIG. 1, reference numeral 20 is an insulating base material, 21 is a through hole, 22 is an insulating material, 23 is a connection particle, 24 is a conductive member, and 25 is a double-sided printed board material.

本実施形態の製造方法では、まず、絶縁基材２０を用意し（図１（ａ））、この絶縁基材２０の所定位置に１つ以上の貫通穴２１を穿設する（図１（ｂ））。
本発明において用いられる絶縁基材２０としては、特に限定されず、各種の絶縁材料で作られた所望の厚さの絶縁基材を用いることができる。ＦＰＣを製造する場合には、ポリイミドシートなどの薄い可撓性樹脂シートを用いることが望ましい。その場合の絶縁基材２０の厚さは、１０〜５０μｍの範囲が望ましい。 In the manufacturing method of the present embodiment, first, an insulating base material 20 is prepared (FIG. 1A), and one or more through holes 21 are formed at predetermined positions of the insulating base material 20 (FIG. 1B). )).
The insulating base material 20 used in the present invention is not particularly limited, and an insulating base material having a desired thickness made of various insulating materials can be used. When manufacturing FPC, it is desirable to use a thin flexible resin sheet such as a polyimide sheet. In this case, the thickness of the insulating base material 20 is desirably in the range of 10 to 50 μm.

絶縁基材２０に貫通穴２１を穿設する方法は、特に限定されず、レーザー加工、パンチング、ドリル加工などの従来より周知の穴開け加工法を用い、基材の材質や厚みなどに応じて適宜選択して実施することができる。穿設される貫通穴２１の穴径や穴形状も特に限定されず、種々の穴径の円形穴、楕円形、多角形などの貫通穴を１つ以上穿設することができる。また、この貫通穴２１は、基材の表裏で一定の穴径のストレートな貫通穴としてもよいし、いずれか一方の側の穴が広く、他方の側が窄まった形状などとしてもよい。 The method of drilling the through-hole 21 in the insulating base material 20 is not particularly limited, and a conventionally well-known drilling method such as laser processing, punching, or drilling is used, and depending on the material and thickness of the base material. It can be implemented by appropriately selecting. The hole diameter and hole shape of the through-hole 21 to be drilled are not particularly limited, and one or more through-holes having various hole diameters such as circular holes, ellipses, and polygons can be drilled. Further, the through hole 21 may be a straight through hole having a constant hole diameter on the front and back of the base material, or may have a shape in which a hole on one side is wide and the other side is narrowed.

次に、図１（ｃ）に示すように、絶縁基材２０の一方の面側に、液状の絶縁材料２２を塗布する。この絶縁材料２２は、この後の工程で貫通穴部に接続粒子２３を付着（接着又は粘着を含む）させることができればよく、その材質、厚さは特に限定されない。また、絶縁基材２０の塗布範囲は、絶縁基材２０の一方の面側に限定されず、少なくとも貫通穴２１の周辺（接続粒子２３の直径が貫通穴２１の穴径より大きい場合）又は貫通穴２１の内周面（接続粒子２３の直径が貫通穴２１の穴径より小さい場合）とすることができる。 Next, as shown in FIG. 1C, a liquid insulating material 22 is applied to one surface side of the insulating base material 20. The insulating material 22 is not particularly limited as long as the connection particles 23 can be attached (including adhesion or adhesion) to the through-hole portion in the subsequent process. Further, the application range of the insulating base material 20 is not limited to one surface side of the insulating base material 20, and at least the periphery of the through hole 21 (when the diameter of the connection particle 23 is larger than the hole diameter of the through hole 21) or the through hole. The inner peripheral surface of the hole 21 (when the diameter of the connection particle 23 is smaller than the diameter of the through hole 21) can be used.

この液状の絶縁材料２２としては、ポリイミド、ポリエーテルイミド、ポリアミドイミド、液晶ポリマーから選択される熱可塑性樹脂の溶液または前駆体溶液、或いはエポキシ樹脂やフェノール樹脂などの熱硬化性樹脂の溶液または前駆体溶液などを用いることができる。この液状の絶縁材料２２として、熱プレス時に接着性を発揮する熱可塑性ポリイミドなどを用いることで、絶縁基材２０に導電部材２４を重ね合わせて熱プレスする際に、絶縁基材２０と導電部材２４とを貼り合わせることができる。なお、その場合、接続粒子２３を乗せる面の反対側の表層に接着性の材料を塗布する必要がある。 The liquid insulating material 22 includes a solution or precursor solution of a thermoplastic resin selected from polyimide, polyetherimide, polyamideimide, and liquid crystal polymer, or a solution or precursor of a thermosetting resin such as an epoxy resin or a phenol resin. A body solution or the like can be used. As the liquid insulating material 22, the insulating base material 20 and the conductive member are used when the conductive member 24 is superposed on the insulating base material 20 by hot pressing by using thermoplastic polyimide or the like that exhibits adhesiveness during hot pressing. 24 can be bonded together. In this case, it is necessary to apply an adhesive material to the surface layer opposite to the surface on which the connection particles 23 are placed.

この液状の絶縁材料２２を絶縁基材２０の一方の面側に塗布する方法としては、例えば、スクリーン印刷、スピンコート、スプレーコートなどの方法を用いることができる。塗布した際に貫通穴２１を絶縁材料２２の液体が覆ってしまわぬよう、液状の絶縁材料２２の粘度は１０〜１００ポイズの範囲とすることが望ましい。この絶縁材料２２の粘度は、絶縁材料２２に加える溶剤の量などによって調整することができる。 As a method for applying the liquid insulating material 22 to one surface side of the insulating base material 20, for example, a method such as screen printing, spin coating, spray coating, or the like can be used. The viscosity of the liquid insulating material 22 is preferably in the range of 10 to 100 poise so that the liquid of the insulating material 22 does not cover the through hole 21 when applied. The viscosity of the insulating material 22 can be adjusted by the amount of solvent added to the insulating material 22.

次に、図１（ｄ）に示すように、絶縁材料２２を塗布した絶縁基材２０の貫通穴２１の中又は上に、銅などの導電材料からなる接続粒子２３をマウンター等で位置合わせをして乗せ、絶縁材料２２に付着させる。接続粒子２３を乗せたとき、貫通穴２１の周り又は内壁面が液状の絶縁材料２２によって覆われているので、貫通穴２１の上又は中に配置した接続粒子２３は、絶縁材料２２に付着してその位置から動きにくくなり、貫通穴２１の上に接続粒子２３を固定することができる。接続粒子２３を貫通穴２１へ固定するためには、絶縁材料２２の液の粘度は４０ポイズ以上であることが好ましい。塗布時に粘性が低く接続粒子２３を固定できない場合、塗布後に乾燥させて溶媒の一部を蒸発させることによって、液体の粘度を４０ポイズ以上に上げると良い。さらに、接続粒子２３を乗せた後、真空引きや熱処理等で溶媒を除去し、接続粒子２３を貫通穴２１部分へ固定することが望ましい。 Next, as shown in FIG. 1 (d), the connecting particles 23 made of a conductive material such as copper are aligned in the through hole 21 of the insulating base material 20 coated with the insulating material 22 with a mounter or the like. And is attached to the insulating material 22. When the connection particles 23 are placed, the periphery of the through hole 21 or the inner wall surface is covered with the liquid insulating material 22, so that the connection particles 23 disposed on or in the through hole 21 adhere to the insulating material 22. Therefore, the connection particles 23 can be fixed on the through holes 21. In order to fix the connecting particles 23 to the through holes 21, the viscosity of the liquid of the insulating material 22 is preferably 40 poise or more. When the connecting particles 23 cannot be fixed because the viscosity is low at the time of application, the viscosity of the liquid may be increased to 40 poise or more by drying after application and evaporating a part of the solvent. Furthermore, after the connection particles 23 are placed, it is desirable to remove the solvent by evacuation or heat treatment to fix the connection particles 23 to the through holes 21.

この接続粒子２３の材質は、銅以外にも、軟らかく、融点の低いスズ、亜鉛、アルミニウムやこれらの合金でも良い。他にもクロム、チタン、チタン−タングステン合金などでも良い。また、接続粒子２３の形状は、球状、円柱状、円錐状、直方体状、多角錐状などでもよい。接続粒子２３の直径は、貫通穴２１の穴径及び穴容積に応じて適宜設定されるが、例えば５０〜２００μｍの範囲が好ましい。 The connecting particles 23 may be made of soft, low melting point tin, zinc, aluminum or alloys thereof other than copper. In addition, chromium, titanium, titanium-tungsten alloy, or the like may be used. Further, the connecting particles 23 may have a spherical shape, a cylindrical shape, a conical shape, a rectangular parallelepiped shape, a polygonal pyramid shape, or the like. The diameter of the connection particle 23 is appropriately set according to the hole diameter and the hole volume of the through hole 21, and for example, a range of 50 to 200 μm is preferable.

次に、図１（ｅ）に示すように、接続粒子２３を乗せた絶縁基材２０の両面に、銅などの導電材料からなるシート状の導電部材２４を重ね合わせ、熱プレスする。この熱プレスにより、接続粒子２３は潰れて貫通穴２１に押し込まれて貫通穴２１を満たし、図１（ｆ）に示す構造のプリント基板用材料２５が得られる。 Next, as shown in FIG.1 (e), the sheet-like electrically-conductive member 24 which consists of electrically conductive materials, such as copper, is piled up on both surfaces of the insulating base material 20 on which the connection particle 23 was mounted, and it heat-presses. By this hot pressing, the connecting particles 23 are crushed and pushed into the through holes 21 to fill the through holes 21, and a printed board material 25 having a structure shown in FIG. 1 (f) is obtained.

この導電部材２４としては、銅箔が好ましいが、銅以外にも、軟らかく、融点の低いスズ、亜鉛、アルミニウムやこれらの合金でも良い。他にもクロム、チタン、チタン−タングステン合金などでも良い。特に、接続粒子２３と導電部材２４の材質を同じとすれば、接続抵抗が低くなることから好ましい。本発明において、接続粒子２３と導電部材２４とを銅で構成することが特に好ましい。また、導電部材２４の厚さは、３〜５０μｍの範囲が望ましい。 The conductive member 24 is preferably a copper foil, but may be tin, zinc, aluminum, or an alloy thereof that is soft and has a low melting point, other than copper. In addition, chromium, titanium, titanium-tungsten alloy, or the like may be used. In particular, it is preferable to use the same material for the connection particles 23 and the conductive member 24 because the connection resistance is lowered. In the present invention, it is particularly preferable that the connection particles 23 and the conductive member 24 are made of copper. The thickness of the conductive member 24 is preferably in the range of 3 to 50 μm.

接続粒子２３を乗せた絶縁基材２０の両面に導電部材２４を重ね合わせ、熱プレスする際の温度条件は、１８０℃以上、好ましくは２４０℃以上とする。
この熱プレスによって、接続粒子２３は潰れ、摩擦の効果により接続粒子２３と導電部材２４の表面の酸化被膜が破壊され、純粋な金属が出てくるため、金属結合によって接続粒子２３と導電部材２４とが強固に接合される。純粋な金属同士は金属結合を形成して強固に接合できるため、接続粒子２３と導電部材２４とは低抵抗で電気的に接続される。 The temperature condition when the conductive member 24 is superposed on both surfaces of the insulating base material 20 on which the connecting particles 23 are placed and hot-pressed is 180 ° C. or higher, preferably 240 ° C. or higher.
By this heat press, the connection particles 23 are crushed, and the oxide film on the surfaces of the connection particles 23 and the conductive member 24 is destroyed due to the effect of friction, so that pure metal comes out. Are firmly joined. Since pure metals can form a metal bond and can be joined firmly, the connection particles 23 and the conductive member 24 are electrically connected with low resistance.

また、この熱プレスによって接続粒子２３が導電部材２４と結合するのと同時に、絶縁基材２０の絶縁材料２２と導電部材２４とが貼り合わせられる。絶縁基材２０と導電部材２４との十分な密着強度を得るため、絶縁材料２２は、絶縁基材２０の表層側と導電部材２４の表面に対し十分な接着性を有することが望ましい。 Further, at the same time when the connecting particles 23 are bonded to the conductive member 24 by this hot pressing, the insulating material 22 of the insulating base material 20 and the conductive member 24 are bonded together. In order to obtain sufficient adhesion strength between the insulating base material 20 and the conductive member 24, it is desirable that the insulating material 22 has sufficient adhesion to the surface layer side of the insulating base material 20 and the surface of the conductive member 24.

熱プレスによって、図１（ｆ）に示すように、貫通穴２１内部は、潰れた接続粒子２３で満たされ、基材両側の導電部材２４が、潰れた接続粒子２３によって電気的に接続されたプリント基板用材料２５が作製できる。 As shown in FIG. 1 (f), the inside of the through hole 21 is filled with the crushed connection particles 23 by the heat press, and the conductive members 24 on both sides of the base material are electrically connected by the crushed connection particles 23. The printed board material 25 can be produced.

次に、基材両側の導電部材２４をエッチング等でパターン形成することによって、両面プリント基板（図示せず）が形成される。 Next, by patterning the conductive members 24 on both sides of the base material by etching or the like, a double-sided printed board (not shown) is formed.

本実施形態によれば、絶縁基材２０の貫通穴部に液状の絶縁材料２２を塗布し接続粒子２３を固定できるので、ＦＰＣを作製する際に薄い絶縁基材２０を用いても、接続粒子２３が貫通穴２１からずれることがなく、プレス後に導通不良を生じ難いプリント基板を簡単に製造することができる。 According to this embodiment, since the liquid insulating material 22 can be applied to the through-hole portion of the insulating base material 20 and the connection particles 23 can be fixed, the connection particles can be used even when the thin insulating base material 20 is used when manufacturing the FPC. 23 is not displaced from the through hole 21, and a printed circuit board that is less likely to cause poor conduction after pressing can be easily manufactured.

前記実施形態では、絶縁基材２０の両面側に銅箔などの導電部材を貼り合わせ、回路パターンを形成して両面プリント基板を作製する方法を例示しているが、これに別の基板を積層して多層プリント基板を製造することもできる。この場合には、貫通穴部分へ接続粒子を乗せた別の絶縁材料シートを用意し、パターン形成した両面プリント基板へ位置合わせをし、外側を導電部材で挟んでプレスを行う。プレス後、両側の導電部材のパターン形成を行うことによって、導電部材が４層構造の多層プリント基板を作製することができる。 In the above embodiment, a method for producing a double-sided printed board by bonding a conductive member such as a copper foil to both sides of the insulating base material 20 and forming a circuit pattern is illustrated. Thus, a multilayer printed board can be manufactured. In this case, another insulating material sheet in which the connecting particles are placed in the through hole portion is prepared, aligned with the patterned double-sided printed board, and pressed outside with the conductive member interposed therebetween. After the pressing, patterning of the conductive members on both sides is performed, whereby a multilayer printed board having a four-layer structure of the conductive members can be produced.

図１に示す製造工程に従い、両面プリント基板を作製した。
絶縁基材２０として、２５μｍ厚の熱可塑性ポリイミド基材（縦２５０ｍｍ、横３００ｍｍ）を用い、接続粒子２３として純銅（Ｃｕ）からなる直径５０μｍの接続粒子を用いた。また導電材料２４として、厚さ１８μｍの銅箔（縦２５０ｍｍ、横３００ｍｍ）を用いた。さらに、液状の絶縁材料２２として、粘度５０ポイズの液状の熱可塑性ポリイミドを用いた。 A double-sided printed circuit board was produced according to the manufacturing process shown in FIG.
A 25 μm-thick thermoplastic polyimide substrate (250 mm long and 300 mm wide) was used as the insulating substrate 20, and connecting particles having a diameter of 50 μm made of pure copper (Cu) were used as the connecting particles 23. Further, as the conductive material 24, a copper foil (length 250 mm, width 300 mm) having a thickness of 18 μm was used. Further, as the liquid insulating material 22, liquid thermoplastic polyimide having a viscosity of 50 poise was used.

まず、絶縁基材２０に直径５０μｍの貫通穴２１を２０００個、レーザー加工によってテーパーがついた形状に穿設した。
次に、貫通穴２１を穿設した絶縁基材２０の片側に、液状の絶縁材料２２として、粘度５０ポイズの熱可塑性ポリイミドをスピンコートによって塗布した。この塗布厚は２０μｍであり、乾燥後の絶縁材料の厚さは２μｍであった。
次に、貫通穴２１上に直径５０μｍの接続粒子２３をマウンター（ＹＡＭＡＨＡ発動機社製、商品名ｉ−ｃｕｂｅ２）により固定した。
次に、温度条件２４０℃で熱プレスし、絶縁基材２０の両面に導電部材２４を貼り合わせた。この熱プレスによって接続粒子２３が潰れて貫通穴を埋め、両側の導電部材がこの潰れた接続粒子２３により電気的に接続された。熱プレス後、基板の総厚は６３μｍとなった。その後、両側の導電部材にエッチングを施し、回路パターンを形成して両面プリント基板を作製した。 First, 2000 through-holes 21 having a diameter of 50 μm were drilled in the insulating base material 20 in a tapered shape by laser processing.
Next, a thermoplastic polyimide having a viscosity of 50 poise was applied as a liquid insulating material 22 to one side of the insulating base material 20 having the through holes 21 by spin coating. The coating thickness was 20 μm, and the thickness of the insulating material after drying was 2 μm.
Next, connecting particles 23 having a diameter of 50 μm were fixed on the through holes 21 by a mounter (trade name i-cube 2 manufactured by YAMAHA MOTOR Co., Ltd.).
Next, hot pressing was performed at a temperature condition of 240 ° C., and the conductive member 24 was bonded to both surfaces of the insulating base material 20. By this hot pressing, the connecting particles 23 were crushed to fill the through holes, and the conductive members on both sides were electrically connected by the crushed connecting particles 23. After hot pressing, the total thickness of the substrate was 63 μm. Thereafter, the conductive members on both sides were etched to form a circuit pattern to produce a double-sided printed board.

得られた両面プリント基板は、潰れた接続粒子２３と両側の導電部材２４とが金属結合で接合され、両側の回路パターンが潰れた接続粒子２３により電気的接続されていた。 In the obtained double-sided printed circuit board, the crushed connection particles 23 and the conductive members 24 on both sides were joined by metal bonds, and the connection patterns 23 in which the circuit patterns on both sides were crushed were electrically connected.

本発明によるプリント基板の製造方法の一実施形態を示す断面図である。It is sectional drawing which shows one Embodiment of the manufacturing method of the printed circuit board by this invention. 従来の層間導通方式の一例を示す断面図である。It is sectional drawing which shows an example of the conventional interlayer conduction system. 従来の層間導通方式の他の例を示す断面図である。It is sectional drawing which shows the other example of the conventional interlayer conduction system.

符号の説明Explanation of symbols

２０…絶縁基材、２１…貫通穴、２２…絶縁材料、２３…接続粒子、２４…導電部材、２５…両面プリント基板用材料。
DESCRIPTION OF SYMBOLS 20 ... Insulating base material, 21 ... Through-hole, 22 ... Insulating material, 23 ... Connection particle | grains, 24 ... Conductive member, 25 ... Material for double-sided printed circuit boards.

Claims

１つ以上の貫通穴が設けられた絶縁基材の少なくとも前記貫通穴の周辺又は貫通穴の内周面に液状の絶縁材料を塗布し、次いで導電材料からなる接続粒子を前記貫通穴部に配置し、次いで前記絶縁基材の両面に導電部材を重ね合わせてこれらを加熱、加圧し、前記接続粒子を押し潰し、この接続粒子によって両側の導電部材間を電気的に接続し、次いで導電部材にパターン形成を行いプリント基板を得ることを特徴とするプリント基板の製造方法。 A liquid insulating material is applied to at least a periphery of the through hole or an inner peripheral surface of the through hole of the insulating base material provided with one or more through holes, and then connecting particles made of a conductive material are arranged in the through hole portion. Then, conductive members are superposed on both surfaces of the insulating base material, and these are heated and pressurized to crush the connecting particles, and the connecting particles electrically connect the conductive members on both sides, A method of manufacturing a printed circuit board, comprising performing pattern formation to obtain a printed circuit board.

接続粒子及び導電部材が銅であり、接続粒子と導電材料とが金属結合により接合されることを特徴とする請求項１に記載のプリント基板の製造方法。 The method for manufacturing a printed circuit board according to claim 1, wherein the connection particles and the conductive member are copper, and the connection particles and the conductive material are bonded by metal bonding.

液状の絶縁材料がポリイミド、ポリエーテルイミド、ポリアミドイミド、液晶ポリマーから選択される熱可塑性樹脂の溶液または前駆体溶液であることを特徴とする請求項１又は２に記載のプリント基板の製造方法。 The method for producing a printed circuit board according to claim 1 or 2, wherein the liquid insulating material is a thermoplastic resin solution or a precursor solution selected from polyimide, polyetherimide, polyamideimide, and liquid crystal polymer.

液状の絶縁材料の粘度が１０〜１００ポイズの範囲であることを特徴とする請求項１〜３のいずれかに記載のプリント基板の製造方法。

The method for producing a printed circuit board according to any one of claims 1 to 3, wherein the viscosity of the liquid insulating material is in the range of 10 to 100 poise.