JP2753756B2 - Electronic circuit board and method of manufacturing the same - Google Patents

Abstract

PURPOSE:To hold electric connection reliability against a mechanical stress and to prevent damage to an electronic circuit mounting component, etc., by providing a linear, a pointlike, a sewing linelike, etc., recess at a suitable position of an insulating base material, and providing the recess at a position not damaging an electronic circuit even if it is broken, damaged. CONSTITUTION:An insulating base material 11 provided with an electronic circuit 13 on its surface, flexible insulating layers 2 laminated on both upper and lower surfaces of the material 11, and a conductor layer 17 provided on the upper layer 2 are provided. A circuit insulating base material 3 provided with an electronic circuit 32 on an insulating layer 31 is laminated on the lower surface of the lower layer 2. V-shaped recesses 12 are formed on the upper and lower surfaces of the insulating substrate 11 in an electronic circuit board 1, and the recess 12 is provided at a position not damaging the circuit 13 even if the recess 12 is broken, damaged. Thus, electric connection reliability is held against a mechanical stress, and the electronic circuit, the mounting components, etc., are not damaged.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は，負荷のかかる状況下で使用される電子回路
基板及びその製造方法に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic circuit board used under a load, and a method for manufacturing the same.

〔従来技術〕(Prior art)

負荷のかかる状況下で使用される電子回路基板として
は，例えば振動の多い車載用モータ，あるいは携帯用の
ポケットベル，メモリーカードなどがある。As an electronic circuit board used under a load, for example, there are an in-vehicle motor with a lot of vibration, a portable pager, a memory card, and the like.

そして，従来，電子回路を施すための絶縁基材として
は，これを大別するとアルミナを代表とする硬質の絶縁
基材と，ガラス繊維−エポキシ樹脂のような柔軟性に富
む樹脂系の絶縁基材がある。Conventionally, insulating base materials for applying electronic circuits are roughly classified into hard insulating base materials such as alumina and resin-based insulating base materials having a high flexibility such as glass fiber-epoxy resin. There is wood.

〔解決しようとする課題〕[Problem to be solved]

ところで，アルミナ，或いはガラス系の絶縁基材は，
硬質であるが，衝撃に弱く，実装或いは使用時に割れ或
いはクラック等が発生し，電子回路や実装電子部品の破
損を生じ易い。By the way, alumina or glass based insulating base material is
Although it is hard, it is susceptible to impact, and cracks or cracks occur during mounting or use, and electronic circuits and mounted electronic components are likely to be damaged.

即ち，第９図に示すごとく，従来の電子回路基板９
は，絶縁基材91の表面に導体層92,92を設け，その上に
抵抗，コンデンサー等の電子部品95が実装されている。
なお，符号93はスルーホールである。That is, as shown in FIG.
Is provided with conductor layers 92, 92 on the surface of an insulating base material 91, on which electronic components 95 such as resistors and capacitors are mounted.
Reference numeral 93 denotes a through hole.

そして，該電子回路基板９に大きい機械的応力が加わ
ると，クラック81,82を生ずる。そして，クラック81,82
は，上記電子部品95や導体層92に損傷を与える。When a large mechanical stress is applied to the electronic circuit board 9, cracks 81 and 82 are generated. And crack 81,82
Damages the electronic component 95 and the conductor layer 92.

一方，セラミック絶縁基材では，強度は高いが，薄い
物を製造することが困難であり，薄い絶縁基材を積層し
てある程度の厚みとして使用しているが一般的である。On the other hand, although ceramic insulating base materials have high strength, it is difficult to manufacture thin objects, and thin insulating base materials are generally laminated and used to a certain thickness.

一方，樹脂系の絶縁基材では曲がることによって破損
することはない。しかし，逆にQFPタイプ（クロッド・
フラット・パック）,SOP（スチール・アウトライン・パ
ッケージ）などの表面実装用のIC,或いは抵抗，コンデ
ンサー等のリジッドな部品を実装した場合には，曲がり
によってこれらの実装部品が接着部からはずれることが
ある。On the other hand, the resin-based insulating base material is not damaged by bending. However, conversely, QFP type
When mounting surface-mounted ICs such as flat packs and SOPs (steel outline packages), or rigid parts such as resistors and capacitors, these parts may come off from the adhesive due to bending. is there.

そのため，比較的大面積で機械的応力の加わる，例え
ば車載モーター駆動用の電子回路基板については，上記
実装部品の接続性に不安がある。For this reason, for an electronic circuit board for driving a vehicle-mounted motor, for example, which has a relatively large area to which mechanical stress is applied, there is a concern about the connectivity of the mounted components.

また，メモリーカードのように携帯用の電子回路基板
においては，不用意な応力が加わらないようにリジッド
なパッケージが必要となる。その結果，電子回路基板が
厚くしかも重量が大きくなるという欠点を有している。Also, in a portable electronic circuit board such as a memory card, a rigid package is required so as not to apply careless stress. As a result, there is a disadvantage that the electronic circuit board is thick and heavy.

本発明は，かかる問題点に鑑み，機械的応力に対して
も，電気的接続信頼性を有し，電子回路実装部品等に損
傷を与えない電子回路基板及びその製造方法を提供しよ
うとするものである。The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an electronic circuit board which has electrical connection reliability against mechanical stress and does not damage electronic circuit mounted components and the like, and a method of manufacturing the same. It is.

〔課題の解決手段〕[Solutions to solve the problem]

本発明は，表面に電子回路を設けた絶縁基材と，該絶
縁基材の上に積層した可撓性の絶縁層と，該絶縁層の上
に設けた導体層とよりなる電子回路基板であって，上記
絶縁基材はその片面又は両面の適宜の場所に線状，点
状，ミシン目状等の凹所を設けてなり，かつ該凹所はこ
の部分に折れ，破断を生じても電子回路に損傷を与える
ことのない位置に設けてあることを特徴とする電子回路
基板にある。The present invention relates to an electronic circuit board comprising an insulating base having an electronic circuit provided on a surface thereof, a flexible insulating layer laminated on the insulating base, and a conductor layer provided on the insulating layer. The insulating base material is provided with a linear, dotted, or perforated recess at an appropriate location on one or both surfaces thereof, and the recess may be broken or broken at this portion. An electronic circuit board is provided at a position where the electronic circuit is not damaged.

本発明において最も注目すべきことは，上記絶縁基材
に予め凹所を設けておくことにある。該凹所は，電子回
路基板に曲げ等の機械的応力が加わった場合に，曲げや
破断を生じさせる部位である。該凹所は，絶縁基材の片
面又は両面に設ける。また，凹所は１枚の絶縁基材にお
いて１ケ所ないし数ケ所設ける。また，凹所は第１図，
第２図に示すごとき連続した線状であっても，或いは断
続的な線状（ミシン目状）であっても良い。また，独立
した円状，角状等の凹所を線状に並べることもできる
（第８図参照）。The most remarkable point in the present invention is that a recess is provided in advance in the insulating base material. The recess is a portion that bends or breaks when mechanical stress such as bending is applied to the electronic circuit board. The recess is provided on one or both sides of the insulating base material. Also, one or several recesses are provided in one insulating base material. The recess is shown in Fig. 1,
It may be a continuous linear shape as shown in FIG. 2 or an intermittent linear shape (perforated shape). In addition, independent circular or angular recesses can be arranged linearly (see FIG. 8).

この凹所は，当然のことながら，電子回路に支障のな
い部分に形成され，凹所において絶縁基材が折れ，破断
を生じても電子回路或いは実装部品にダメージを与えな
い部分に設ける。Naturally, this recess is formed in a portion that does not hinder the electronic circuit, and is provided in a portion that does not damage the electronic circuit or the mounted components even if the insulating base material is broken or broken in the recess.

また，凹所を複数個設ける場合には，凹所の間隔は，
絶縁基材の厚み，強度，サイズ，ヤング率等で決定され
るが通常は5mm〜30mmである。これにより，絶縁基材の
割れ或いは曲がりがスムースとなる。なお，点状凹所を
線列状に並べる場合，該凹所列間の間隔は2mm以下とす
ることが好ましい。これよりも大きい間隔になると曲
げ，破断を生じ難い。When multiple recesses are provided, the spacing between the recesses is
The thickness is determined by the thickness, strength, size, Young's modulus, etc. of the insulating base material, but is usually 5 mm to 30 mm. Thereby, cracking or bending of the insulating base material becomes smooth. When the dot-shaped recesses are arranged in a line, the interval between the recesses is preferably 2 mm or less. If the interval is larger than this, bending and breakage hardly occur.

また，凹所の深さは絶縁基材厚みの５％〜80％とする
ことが好ましい。これにより，通常使用時における曲げ
程度に対しては，電子回路基板は損傷を受けず，異常な
機械的応力が加わった時には，該凹所よりスムーズに曲
がり，破断を生じさせることができる。そして，上記凹
所の深さは，アルミナセラミックスのごとき硬質の絶縁
基材については浅い目に，一方ガラス・エポキシ基板の
ように曲がり易いものについては深い目に形成する。The depth of the recess is preferably 5% to 80% of the thickness of the insulating base material. Thus, the electronic circuit board is not damaged with respect to the degree of bending during normal use, and can bend more smoothly from the recess and cause breakage when abnormal mechanical stress is applied. The depth of the recess is formed to be shallow for a hard insulating base material such as alumina ceramics, and to be deep for a bendable material such as a glass epoxy substrate.

また，セラミックやガラス絶縁基材等の硬質の絶縁基
材は，片側にのみ凹所を形成し，絶縁基材の割れをコン
トロールできる。一方，表裏にプリプレグのごとく補強
層をもった樹脂−セラミック複合基材等の比較的軟質の
絶縁基材は両側から凹所を形成した方が良い。In addition, a hard insulating base material such as a ceramic or glass insulating base material has a recess formed on only one side, so that cracking of the insulating base material can be controlled. On the other hand, a relatively soft insulating base material such as a resin-ceramic composite base material having a reinforcing layer like a prepreg on the front and back sides is preferably formed with recesses from both sides.

また，凹所は,CO₂,YAG,エキシマ等のレーザー加工，
回転刃物による機械的加工，超音波加工等によって形成
することができる。The recess is made by laser processing of CO ₂ , YAG, excimer, etc.
It can be formed by mechanical processing using a rotary blade, ultrasonic processing, or the like.

絶縁基材としては，セラミック基板，ガラス基板，セ
ラミック或いはガラスと樹脂との複合基板などがある。
また，絶縁基材上には電子回路が形成してある。Examples of the insulating substrate include a ceramic substrate, a glass substrate, and a composite substrate of ceramic or glass and resin.
An electronic circuit is formed on the insulating base material.

絶縁層としては可撓性があり，耐曲げ疲労性に強い樹
脂，例えばポリエチレン，塩化ビニール，ポリプロピレ
ン，ポリエステル，ナイロン，ポリイミド，エポキシ樹
脂等が使用できる。また，ガラスファイバーエポキシ樹
脂，アラミド繊維入エポキシ−プリプレグ，ガラスファ
イバービスマレイミド・トリアジン−プリプレグ等が使
用でき，単独或いは数種の層を積層したものを用いる。As the insulating layer, a resin that is flexible and has high resistance to bending fatigue, such as polyethylene, vinyl chloride, polypropylene, polyester, nylon, polyimide, and epoxy resin, can be used. Further, glass fiber epoxy resin, epoxy-prepreg containing aramid fiber, glass fiber bismaleimide-triazine-prepreg, etc. can be used, and a single layer or a laminate of several layers is used.

また，上記絶縁層以外にも，電子回路を形成した絶縁
層を用いることもできる。In addition to the above-described insulating layer, an insulating layer on which an electronic circuit is formed can be used.

また，前記絶縁基材と，絶縁層を介して密着された導
体層とよりなる電子回路基板には，スルーホールを形成
し，無電解メッキ，スパッタリング等により，該スルー
ホール内部に導体層を形成し，絶縁基材上の電子回路と
導体層間の導通を行う。そして，電子回路基板の上方に
設けた導体層には，シリコンチップ，モールドIC,チッ
プ抵抗，コンデンサ，コイル等の電子部品が実装され
る。これら電子部品の実装は，上記凹所の位置を避けて
行われる。Also, a through hole is formed in an electronic circuit board comprising the insulating base material and a conductor layer adhered through an insulating layer, and a conductor layer is formed inside the through hole by electroless plating, sputtering, or the like. Then, conduction between the electronic circuit on the insulating base material and the conductive layer is performed. Electronic components such as a silicon chip, a molded IC, a chip resistor, a capacitor, and a coil are mounted on the conductor layer provided above the electronic circuit board. The mounting of these electronic components is performed avoiding the position of the recess.

次に，上記電子回路基板を製造する方法としては，電
子回路を設けた絶縁基材の片面又は両面の適宜の場所に
凹所を形成し，次いで該絶縁基材の上に絶縁層を積層
し，該絶縁層の上に導体層を積層し，その後これらを接
合することを特徴とする電子回路基板の製造方法があ
る。Next, as a method of manufacturing the electronic circuit board, a recess is formed at an appropriate place on one or both sides of an insulating substrate provided with an electronic circuit, and then an insulating layer is laminated on the insulating substrate. There is a method for manufacturing an electronic circuit board, which comprises laminating a conductor layer on the insulating layer, and thereafter joining the conductor layers.

上記製造方法において，絶縁基材，絶縁層，導体層の
接合は，これらを加圧，加熱することなどにより行う。In the above manufacturing method, the joining of the insulating base material, the insulating layer, and the conductor layer is performed by pressurizing and heating them.

〔作用及び効果〕[Action and effect]

本発明においては，電子回路基板に外部より機械的応
力が加わると，電子回路基板に曲げ力が加わる。このと
き，上記外力が小さい時には，該電子回路基板は若干の
曲げを生ずる程度であり，外力が除かれると元の直線状
態に復帰する。In the present invention, when external mechanical stress is applied to the electronic circuit board, a bending force is applied to the electronic circuit board. At this time, when the external force is small, the electronic circuit board is slightly bent, and returns to the original linear state when the external force is removed.

一方，上記外力が大きい時には，電子回路基板には大
きな曲げ力が加わり，電子回路基板に損傷を生ずるおそ
れがある。しかし，このとき該電子回路基板の絶縁基材
は，上記線状或いは点在する凹所において折れ又は破断
を生ずる（第７図参照）。そして，上記凹所は，電子回
路更には実装部品に損傷を与えない位置に設けてある
（第１図，第７図参照）ため，上記折れ，破断は，電子
回路及び実装部品には何ら影響を与えない。On the other hand, when the external force is large, a large bending force is applied to the electronic circuit board, and the electronic circuit board may be damaged. However, at this time, the insulating base material of the electronic circuit board breaks or breaks in the linear or dotted recesses (see FIG. 7). Since the recess is provided at a position that does not damage the electronic circuit and the mounted components (see FIGS. 1 and 7), the breakage or breakage has no effect on the electronic circuit and the mounted component. Do not give.

また，絶縁基材が，上記のごとく，折れ，破断を生じ
た場合でも，該絶縁基材の外側には柔軟性のある可撓性
の絶縁層が積層してあるため，絶縁基材は分離されるこ
となく，ほぼ同じ位置に保持される。それ故，電子回路
に支障を生じることもない。Even if the insulating base material breaks or breaks as described above, the insulating base material is separated because the flexible insulating layer is laminated outside the insulating base material. It is held in almost the same position without being performed. Therefore, there is no trouble in the electronic circuit.

〔効 果〕(Effect)

したがって，本発明によれば，機械的応力に対しても
電気的接続信頼性を有し，また電子回路，実装部品等に
損傷を与えることのない電子回路基板を提供することが
できる。Therefore, according to the present invention, it is possible to provide an electronic circuit board which has electrical connection reliability against mechanical stress and does not damage electronic circuits, mounted components and the like.

〔実施例〕〔Example〕

第１実施例 本発明の実施例にかかる電子回路基板につき，第１図
及び第２図を用いて説明する。First Embodiment An electronic circuit board according to an embodiment of the present invention will be described with reference to FIGS.

本例の電子回路基板１は，第１図に示すごとく，表面
に電子回路13を設けた絶縁基材11と，該絶縁基材11の上
下両面に積層した可撓性の絶縁層２と，上側の絶縁層２
の上面に設けた導体層17とを有する。また，下側の絶縁
層２の下面には絶縁層31上に電子回路32を設けた回路絶
縁基材３を積層している。更に該絶縁層31の下面には導
体層17を有する。As shown in FIG. 1, an electronic circuit board 1 according to the present embodiment includes an insulating base material 11 having an electronic circuit 13 provided on a surface thereof, a flexible insulating layer 2 laminated on upper and lower surfaces of the insulating base material 11, and Upper insulating layer 2
And a conductor layer 17 provided on the upper surface of the substrate. On the lower surface of the lower insulating layer 2, a circuit insulating substrate 3 having an electronic circuit 32 provided on the insulating layer 31 is laminated. Further, the lower surface of the insulating layer 31 has a conductor layer 17.

また，第１図，第２図に示すごとく，該電子回路基板
１の内部の上記絶縁基材11には，その上面及び下面にＶ
字状溝の凹所12が形成されている。該凹所12は，同図に
おいては，上面と下面に互いに対向する位置に,2ケ所設
けてある。また，該凹所12は，これが折れ，破断を生じ
ても，電子回路13に損傷を与えることのない位置に設け
てある。As shown in FIGS. 1 and 2, the insulating substrate 11 inside the electronic circuit board 1 has V
A concave portion 12 of a U-shaped groove is formed. In the figure, two recesses 12 are provided at positions opposing each other on the upper surface and the lower surface. The recess 12 is provided at a position where the electronic circuit 13 is not damaged even if the recess 12 is broken or broken.

また，電子回路基板１は，スルーホール16を有し，電
子回路13,電子回路32,導体層17間を導通している。ま
た，電子回路基板１の上下両面には，チップ抵抗，コン
デンサ等の電子部品95が，上記凹所12の上下に位置しな
いように，実装されている。Further, the electronic circuit board 1 has a through hole 16, and conducts between the electronic circuit 13, the electronic circuit 32, and the conductor layer 17. Electronic components 95 such as chip resistors and capacitors are mounted on both upper and lower surfaces of the electronic circuit board 1 so as not to be located above and below the recess 12.

また，上記絶縁基材11の厚みは0.8mm,凹所12の深さは
0.1mmである。The thickness of the insulating substrate 11 is 0.8 mm, and the depth of the recess 12 is
0.1 mm.

次に，上記電子回路基板１の製造方法につき，第３図
〜第６図により説明する。Next, a method of manufacturing the electronic circuit board 1 will be described with reference to FIGS.

まず，第３図に示すごとき，絶縁基材11を準備する。
該絶縁基材11は，その上，下両面に電子回路13を形成し
ており，また２ケ所において上下両面にＶ字状溝の凹所
12を形成してある。First, as shown in FIG. 3, an insulating base material 11 is prepared.
The insulating substrate 11 has electronic circuits 13 formed on both upper and lower surfaces thereof, and has V-shaped groove recesses on both upper and lower surfaces.
12 is formed.

次に，第４図に示すごとく，上記絶縁基材11の上下面
にそれぞれ絶縁層２を配置，また下側の絶縁層２の下に
前記回路絶縁基材３を配置し，これらを加熱圧着して積
層体とする。その後，該積層体に第５図に示すごとく，
スルーホールを穿設する。Next, as shown in FIG. 4, the insulating layers 2 are respectively disposed on the upper and lower surfaces of the insulating base 11, and the circuit insulating base 3 is disposed below the lower insulating layer 2, and these are heated and pressed. To form a laminate. Then, as shown in FIG.
Drill through holes.

次いで，スルーホール内も含めて，上記積層体の全表
面に金属メッキ170を施し，更に常法により該金属メッ
キ170をエッチング処理して導体層を形成した。次い
で，電子回路基板上面に電子部品95を実装する。これに
より，前記第１図に示した電子回路基板１を得た。Next, a metal plating 170 was applied to the entire surface of the laminate including the inside of the through-hole, and the metal plating 170 was subjected to an etching treatment by a conventional method to form a conductor layer. Next, the electronic component 95 is mounted on the upper surface of the electronic circuit board. Thus, the electronic circuit board 1 shown in FIG. 1 was obtained.

次に，上記電子回路基板１の使用中において，外力が
加わると，電子回路基板に曲げ力が加わる。この場合，
上記外力が小さい時には，該電子回路基板１は若干の曲
げを生ずるが，外力が除かれると元の直線状態に復帰す
る。Next, when an external force is applied during use of the electronic circuit board 1, a bending force is applied to the electronic circuit board. in this case,
When the external force is small, the electronic circuit board 1 slightly bends, but returns to its original linear state when the external force is removed.

一方，外力が大きい時には，電子回路基板には大きな
曲げ力が加わるため，第７図に示すごとく，電子回路基
板の絶縁基材11は上記Ｖ字状溝の凹所12において折れ又
は破断を生ずる。On the other hand, when the external force is large, a large bending force is applied to the electronic circuit board, so that the insulating substrate 11 of the electronic circuit board breaks or breaks in the recess 12 of the V-shaped groove as shown in FIG. .

しかし，上記凹所12は，前記のごとく，電子回路13,
導体層17,実装電子部品95の配設位置を回避して設けて
あるため，これら電子回路13等が損傷を受けることはな
い。また，外力がある値以上になった時には，上記凹所
12において最初に折れ，破断が発生するので，電子回路
13等の配設部分では折れ，破断が生じない。However, the recess 12 is, as described above, an electronic circuit 13,
Since the conductor layer 17 and the mounted electronic component 95 are provided so as to avoid the disposition, the electronic circuit 13 and the like are not damaged. When the external force exceeds a certain value,
Since the first break and break occurs at 12, the electronic circuit
There is no breakage or breakage at the location where 13 is installed.

更に，上記Ｖ字状溝の凹所12において折れ，破断が発
生しても，絶縁基材11の両表面には，可撓性の絶縁層が
設けてあるので，絶縁基材11は分断されることなく，ほ
ぼ同じ位置に保持される。よれ故，電子回路に支障を生
ずることもない。Further, even if the concave portion 12 of the V-shaped groove breaks or breaks, the insulating base material 11 is divided because the flexible insulating layers are provided on both surfaces of the insulating base material 11. It is held in almost the same position without any Therefore, there is no trouble in the electronic circuit.

第２実施例 本例は，第８図に示すごとく，絶縁基板上に連続して
点在する円錐状の凹所45を設けたものである。該凹所45
は縦方向と横方向に，格子状に連続した凹所列を形成し
ている。Second Embodiment In this embodiment, as shown in FIG. 8, conical recesses 45 are provided continuously on the insulating substrate. The recess 45
Form a continuous row of recesses in a grid pattern in the vertical and horizontal directions.

本例の電子回路基板を製造するに当たっては，まず，
電子回路を形成したリジッドな絶縁基材４を用いる。該
絶縁基材４はコージェライトセラミック層41とその上に
設けたエポキシ樹脂層42とからなる。そして，この絶縁
基材４に，炭酸ガスレーザーにより，連続して点在する
円錐状の凹所45を形成した。レーザー条件は，照射時間
0.1ms,非照射時間0.6ms,パワー27W,点径φ0.2mmであっ
た。In manufacturing the electronic circuit board of this example, first,
A rigid insulating substrate 4 on which an electronic circuit is formed is used. The insulating base 4 comprises a cordierite ceramic layer 41 and an epoxy resin layer 42 provided thereon. Then, conical recesses 45 continuously scattered were formed in the insulating base material 4 by a carbon dioxide gas laser. Laser conditions are irradiation time
The irradiation time was 0.1 ms, the irradiation time was 0.6 ms, the power was 27 W, and the spot diameter was 0.2 mm.

これにより，エポキシ樹脂層の表面では直径が0.2mm,
深さが0.3mmで開口し，上記セラミック層上には直径50
μｍで開口する凹所45が形成された。上記各凹所列の間
隔は縦方向10mm,横方向7mmである。また，各凹所45の間
のピッチは,0.3mmである。As a result, the diameter on the surface of the epoxy resin layer is 0.2 mm,
An opening with a depth of 0.3 mm, a diameter of 50 on the ceramic layer
A recess 45 opening at μm was formed. The interval between the recess rows is 10 mm in the vertical direction and 7 mm in the horizontal direction. The pitch between the recesses 45 is 0.3 mm.

次いで，ガラスクロス−エポキシ樹脂プリプレグを介
して，片面側は銅箔，別の面には回路を施した0.1mmの
ガラスクロス−エポキシ樹脂絶縁基材を積層した。そし
て,180℃,10気圧でオートクレーブにより加圧，加熱
し，絶縁層と導体層を積層密着させた。Next, a glass cloth-epoxy resin insulating base material having a circuit of 0.1 mm was laminated on one side with a copper foil on the other side via a glass cloth-epoxy resin prepreg. Then, pressure and heat were applied by an autoclave at 180 ° C. and 10 atm, and the insulating layer and the conductor layer were laminated and adhered.

次いで，φ0.3mmのドリルによりスルーホールを形成
し，無電解銅メッキ20μｍを行い，スルーホール内及び
表裏の導体層の導通を行った。Next, a through hole was formed by a φ0.3 mm drill, electroless copper plating was performed at 20 μm, and conduction in the through hole and on the front and back conductor layers was performed.

そして，表面の回路に,5×7mmのフリップチップを直
接，半田により接着し，樹脂で封止した。この絶縁基材
は,50m×80mm×1.0mmであり同形状のチップが32個実装
されるメモリーカードである。Then, a 5 x 7 mm flip chip was directly bonded to the circuit on the surface by soldering and sealed with resin. This insulating base material is a memory card having a size of 50 m × 80 mm × 1.0 mm and 32 chips of the same shape mounted thereon.

次に，この電子回路基板の評価を行った。 Next, this electronic circuit board was evaluated.

即ち，この絶縁基材の中央に57kgf加圧を行ったとこ
ろ，曲げ応力は16.8kg/mm²であった。また，該電子回路
基板は,6.35mmの歪みを生じ，連続して点在する凹所の
列に亀裂が入った。しかし，該電子回路基板は，断線す
ることなく，また該フリップチップは剥離することな
く，正常に作動した。That is, when a pressure of 57 kgf was applied to the center of the insulating base material, the bending stress was 16.8 kg / mm ² . In addition, the electronic circuit board had a strain of 6.35 mm, and cracks were formed in the rows of recesses continuously scattered. However, the electronic circuit board operated normally without disconnection, and the flip chip did not peel off.

更に，同じ応力を500回繰り返し，更に85℃−85％湿
度の高温高湿試験を行ったが回路上問題はなかった。Furthermore, the same stress was repeated 500 times, and a high-temperature and high-humidity test at 85 ° C-85% humidity was performed.

これに対し，絶縁基材に凹所を形成していない点以外
は上記と同様の電子回路基板を作製し，同様の試験を行
った。その結果,5.11mmの歪を生じたが，チップの断線
はなかった。しかし，同様に耐久試験を行ったところ，
電子回路基板の中央付近のチップ４個に断線を生じた。
また，他の３個のチップには，同様の高温高湿試験にお
いて，ショートが発生した。また，該電子回路基板につ
いて，よく観察するとチップ下部のセラミック層に亀裂
が認められた。On the other hand, an electronic circuit board similar to the above was produced except that no recess was formed in the insulating base material, and a similar test was performed. As a result, a distortion of 5.11 mm occurred, but there was no disconnection of the chip. However, when a durability test was performed in the same way,
Disconnection occurred in four chips near the center of the electronic circuit board.
Further, short-circuits occurred in the other three chips in the same high-temperature and high-humidity test. When the electronic circuit board was closely observed, cracks were found in the ceramic layer below the chip.

一方，上記のリジットな複合絶縁基材の代わりに，比
較的柔軟と言われている，ガラスクロス−ビスマレイミ
ド−トリアジン絶縁基材を使用した。この絶縁基材には
前記円錐状の凹所は設けていない。そして，上記と同様
に7kgfの力を加えたところ,8.1mmの歪を生じ８個のチッ
プが外れた。そして，耐久試験を行ったところ，すべて
のチップが外れた。On the other hand, a glass cloth-bismaleimide-triazine insulating substrate, which is said to be relatively flexible, was used in place of the rigid composite insulating substrate. The insulating substrate does not have the conical recess. When a force of 7 kgf was applied in the same manner as described above, an 8.1 mm strain was generated, and eight chips came off. When a durability test was performed, all chips came off.

以上述べたごとく，本例の電子回路基板は，たとえ機
械的応力により内部の絶縁基材に亀裂が形成されても，
実装部品に対するストレスがなく，安心して使用できる
ことがわかる。As described above, the electronic circuit board of the present example can be used even if a crack is formed in the internal insulating base material due to mechanical stress.
It is clear that there is no stress on the mounted components and that they can be used with confidence.

【図面の簡単な説明】[Brief description of the drawings]

第１図〜第７図は第１実施例を示し，第１図は電子回路
基板の断面図，第２図は第１図のＡ−Ａ線矢視断面図，
第３図は絶縁基材の斜視図，第４図〜第６図は電子回路
基板の製造工程図，第７図は電子回路基板の折れ曲げ状
態を示す説明図，第８図は第２実施例における電子回路
基板の要部斜視図，第９図は従来の電子回路基板の断面
図である。 １……電子回路基板， 11……絶縁基材， 12……凹所， 13,32……電子回路， 16……スルーホール， 17……導体層， 2,31……絶縁層， 95……電子部品，1 to 7 show a first embodiment, FIG. 1 is a sectional view of an electronic circuit board, FIG. 2 is a sectional view taken along line AA of FIG.
FIG. 3 is a perspective view of the insulating base material, FIGS. 4 to 6 are views showing the manufacturing process of the electronic circuit board, FIG. 7 is an explanatory view showing a bent state of the electronic circuit board, and FIG. FIG. 9 is a perspective view of a main part of an electronic circuit board in an example, and FIG. 9 is a sectional view of a conventional electronic circuit board. 1 ... electronic circuit board, 11 ... insulating base material, 12 ... recess, 13,32 ... electronic circuit, 16 ... through hole, 17 ... conductor layer, 2,31 ... insulating layer, 95 ... ... Electronic components,

Claims (2)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】表面に電子回路を設けた絶縁基材と，該絶
縁基材の上に積層した可撓性の絶縁層と，該絶縁層の上
に設けた導体層とよりなる電子回路基板であって， 上記絶縁基材はその片面又は両面の適宜の場所に線状，
点状，ミシン目状等の凹所を設けてなり，かつ該凹所は
この部分に折れ，破断を生じても電子回路に損傷を与え
ることのない位置に設けてあることを特徴とする電子回
路基板。An electronic circuit board comprising: an insulating base having an electronic circuit provided on a surface thereof; a flexible insulating layer laminated on the insulating base; and a conductor layer provided on the insulating layer. Wherein the insulating base material is linear on one or both sides thereof at an appropriate place,
An electronic device characterized by providing a point-like or perforation-like concave portion, and the concave portion is provided in a position where the electronic circuit is not damaged even if the concave portion is broken or broken. Circuit board. 【請求項２】電子回路を設けた絶縁基材の片面又は両面
の適宜の場所に凹所を形成し，次いで該絶縁基材の上に
絶縁層を積層し，該絶縁層の上に導体層を積層し，その
後これらを接合することを特徴とする電子回路基板の製
造方法。2. An insulative substrate provided with an electronic circuit is provided with a recess in one or both surfaces at appropriate locations, an insulating layer is laminated on the insulating substrate, and a conductor layer is formed on the insulating layer. A method for manufacturing an electronic circuit board, comprising: laminating and then bonding them.