JP2008062565A - Thermal head and its wire bonding method - Google Patents
Thermal head and its wire bonding method Download PDFInfo
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- JP2008062565A JP2008062565A JP2006244455A JP2006244455A JP2008062565A JP 2008062565 A JP2008062565 A JP 2008062565A JP 2006244455 A JP2006244455 A JP 2006244455A JP 2006244455 A JP2006244455 A JP 2006244455A JP 2008062565 A JP2008062565 A JP 2008062565A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
- H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
- H01L2224/484—Connecting portions
- H01L2224/48463—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/74—Apparatus for manufacturing arrangements for connecting or disconnecting semiconductor or solid-state bodies and for methods related thereto
- H01L2224/78—Apparatus for connecting with wire connectors
- H01L2224/7825—Means for applying energy, e.g. heating means
- H01L2224/783—Means for applying energy, e.g. heating means by means of pressure
- H01L2224/78301—Capillary
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
- H01L2224/85—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a wire connector
- H01L2224/8512—Aligning
- H01L2224/85148—Aligning involving movement of a part of the bonding apparatus
- H01L2224/85169—Aligning involving movement of a part of the bonding apparatus being the upper part of the bonding apparatus, i.e. bonding head, e.g. capillary or wedge
- H01L2224/8518—Translational movements
- H01L2224/85181—Translational movements connecting first on the semiconductor or solid-state body, i.e. on-chip, regular stitch
Abstract
Description
本発明は、熱転写型プリンタに搭載されるサーマルヘッド及びそのワイヤーボンディング方法に関する。 The present invention relates to a thermal head mounted on a thermal transfer printer and a wire bonding method thereof.
サーマルヘッドは、複数の発熱抵抗体及び該複数の発熱抵抗体に導通接続した導体を有するヘッド基板と、複数の発熱抵抗体を選択的に通電する駆動回路（駆動ＩＣ）を搭載した回路基板とを備え、上記導体及び駆動回路を介して発熱させた発熱抵抗体を、インクリボンを介して印刷媒体に圧接させることにより、印刷動作する。このようなサーマルヘッドにおいて、対応する導体と駆動回路は、Ａｕワイヤーを用いたワイヤーボンディングによりそれぞれ接続されている。 A thermal head includes a head substrate having a plurality of heating resistors and a conductor conductively connected to the plurality of heating resistors, and a circuit board on which a drive circuit (drive IC) for selectively energizing the plurality of heating resistors is mounted, And a heating resistor that is heated through the conductor and the drive circuit is pressed against a print medium through an ink ribbon to perform a printing operation. In such a thermal head, the corresponding conductor and the drive circuit are connected to each other by wire bonding using Au wires.
図７は、従来のワイヤーボンディング方法の各工程を示している。従来工程では先ず、Ａｕワイヤー１３０を挿通したキャピラリ１４０を準備し（図７（ａ））、このキャピラリ１４０を用いてＡｕワイヤー１３０の一端部１３０ａを駆動回路１２１に接続する（図７（ｂ））。次に、この接続点から垂直にキャピラリ１４０を持ち上げてＡｕワイヤー１３０を繰り出した後、キャピラリ１４０を駆動回路１２１及びヘッド基板１００から離れる方向に移動させ（図７（ｃ））、さらにキャピラリ１４０を垂直に持ち上げることにより、Ａｕワイヤー１３０にループ曲げ部１３０ｃを形成する（図７（ｄ））。続いて、同図７（ｄ）に示すように、駆動回路１２１に接続したＡｕワイヤー１３０の一端部１３０ａを中心とする円弧軌道（図７（ｄ）の鎖線矢印で示す軌道）に沿ってヘッド基板１００の導体１０６上へキャピラリ１４０を移動させたら、キャピラリ１４０を用いてＡｕワイヤー１３０の他端部１３０ｂをヘッド基板１００の導体１０６に接続する（図７（ｅ））。このようにして駆動回路１２１−導体１０６間に接続したＡｕワイヤー１３０は、ループ折り曲げ部１３０ｃを備えることで、ワイヤー高さ（ヘッド基板上面からの高さ）ｈが高く保持される高ループ形状をなし、他部材との接触が防止される。このＡｕワイヤー１３０、回路基板１２０の駆動回路１２１及びヘッド基板１００の導体１０６を含むボンディング部は、保護樹脂によって封止され、プラテンローラ等との接触から保護される。従来のワイヤーボンディング方法を用いたサーマルヘッドは、例えば特許文献１に記載されている。
近年では、更なる高記録密度化及び低コスト化に伴い、ヘッド基板の小型化が進められている。しかしながら、ヘッド基板が小さくなると、該ヘッド基板に対してボンディング部を覆う保護樹脂が相対的に大きくなることから、保護樹脂が印刷媒体に接触して印刷品質を低下させることが問題となってきた。これを解消するにはワイヤー高さを下げて保護樹脂表面を低くすればよいが、上述のワイヤーボンディング方法では、図７（ｃ）〜（ｅ）に示すようにＡｕワイヤー１３０がループ折り曲げ部１３０ｃを有するため、ワイヤー高さを一定以上下げることができない。 In recent years, as the recording density and cost are further increased, the head substrate has been reduced in size. However, when the head substrate is small, the protective resin that covers the bonding portion with respect to the head substrate is relatively large, and thus it has been a problem that the protective resin comes into contact with the print medium and deteriorates the print quality. . In order to solve this problem, it is only necessary to lower the height of the protective resin by lowering the wire height. However, in the above-described wire bonding method, the Au wire 130 is turned into the loop bent portion 130c as shown in FIGS. Therefore, the wire height cannot be lowered beyond a certain level.
本発明は、上記課題に鑑みてなされたものであり、ボンディング部のワイヤー高さを低減できるサーマルヘッド及びそのワイヤーボンディング方法を得ることを目的とする。 The present invention has been made in view of the above problems, and an object thereof is to obtain a thermal head and a wire bonding method thereof that can reduce the wire height of a bonding portion.
本発明は、Ａｕワイヤーを他部材に接触させないことが前提となっている従来のワイヤーボンディング方法とは逆転の発想で、駆動回路に接続したＡｕワイヤーをヘッド基板の回路基板側の角部に打ち当てることで折り曲げれば、該折り曲げ位置でのワイヤー高さを可及的に低減できることに着眼して完成されたものである。 In the present invention, the Au wire connected to the drive circuit is punched at the corner of the circuit board side of the head substrate in the concept of reversing the conventional wire bonding method, which is based on the premise that the Au wire is not in contact with other members. It is completed by paying attention to the fact that the wire height at the bending position can be reduced as much as possible by bending by applying.
すなわち、本発明は、複数の発熱抵抗体及び該複数の発熱抵抗体に導通接続した導体を有するヘッド基板と、複数の発熱抵抗体を選択的に通電する駆動回路を搭載した回路基板とを備え、このヘッド基板の導体と回路基板の駆動回路をＡｕワイヤーにより接続してなるサーマルヘッドにおいて、ヘッド基板と回路基板は、該回路基板の駆動回路上面をヘッド基板上面より下に位置させた状態で隣接配置され、Ａｕワイヤーが、ヘッド基板の回路基板側の角部の上方において、該ヘッド基板上面からの高さが最も高くなるように折り曲げて接続されていることを特徴としている。 That is, the present invention includes a head substrate having a plurality of heating resistors and a conductor conductively connected to the plurality of heating resistors, and a circuit board on which a drive circuit for selectively energizing the plurality of heating resistors is mounted. In the thermal head in which the conductor of the head substrate and the drive circuit of the circuit board are connected by the Au wire, the head substrate and the circuit board are positioned with the upper surface of the drive circuit of the circuit board positioned below the upper surface of the head substrate. Adjacently arranged, the Au wire is connected above the corner of the head substrate on the circuit board side so that the height from the upper surface of the head substrate is bent to be the highest.
また本発明は、複数の発熱抵抗体及び該複数の発熱抵抗体に導通接続した導体を有するヘッド基板と、複数の発熱抵抗体を選択的に通電する駆動回路を搭載した回路基板とを備えたサーマルヘッドにおいて、このヘッド基板の導体と回路基板の駆動回路をＡｕワイヤーにより接続する方法であって、ヘッド基板と前記回路基板を、該回路基板の駆動回路上面をヘッド基板上面より下に位置させて、隣接配置する工程；Ａｕワイヤーを挿通したキャピラリを準備する工程；このキャピラリを用いて回路基板の駆動回路にＡｕワイヤーの一端部を接続する工程；この接続点から前記キャピラリを垂直に持ち上げ、Ａｕワイヤーを繰り出す工程；接続点を中心とする円弧軌道に沿ってキャピラリをヘッド基板側上へ移動させ、この移動中に、Ａｕワイヤーをヘッド基板の回路基板側の角部に打ち当てて折り曲げる工程；及びキャピラリを用いてヘッド基板の導体にＡｕワイヤーの他端部を接続する工程；を有することを特徴としている。 The present invention also includes a head substrate having a plurality of heating resistors and a conductor conductively connected to the plurality of heating resistors, and a circuit board on which a drive circuit for selectively energizing the plurality of heating resistors is mounted. In the thermal head, the conductor of the head substrate and the drive circuit of the circuit board are connected by Au wires, and the upper surface of the drive circuit of the circuit board is positioned below the upper surface of the head board. A step of arranging adjacent ones; a step of preparing a capillary through which an Au wire is inserted; a step of connecting one end of the Au wire to a drive circuit of a circuit board using this capillary; A step of feeding out the Au wire; the capillary is moved on the head substrate side along the circular arc track centering on the connection point, and the Au wire is moved during the movement. It is characterized by having: a step of connecting the other end of the Au wire to the conductor of the head substrate with and capillary; Step bent hit the yer the corners of the circuit board side of the head substrate.
本発明によれば、Ａｕワイヤーがヘッド基板の回路基板側の角部で折り曲げられるので、ワイヤーボンディングにおいて折り曲げ位置で最大となるワイヤー高さを最小限に抑えることができ、ボンディング部のワイヤー高さを低減可能なサーマルヘッド及びそのワイヤーボンディング方法が得られる。 According to the present invention, since the Au wire is bent at the corner on the circuit board side of the head substrate, the maximum wire height at the bending position in wire bonding can be minimized, and the wire height of the bonding portion can be minimized. A thermal head and a wire bonding method thereof can be obtained.
図１及び図２は、本発明を適用したサーマルヘッドの全体構成を示す模式平面図及び断面図である。本サーマルヘッドは、ヘッド基板１と回路基板２０を独立に備えている。 1 and 2 are a schematic plan view and a cross-sectional view showing an overall configuration of a thermal head to which the present invention is applied. The thermal head includes a head substrate 1 and a circuit board 20 independently.
ヘッド基板１は、Ｓｉやセラミック材料、金属材料等からなる放熱性基板２と、この放熱性基板２の上面２ａに例えばガラス等の断熱材料で形成した蓄熱層３と、通電により発熱する複数の発熱抵抗体４と、各発熱抵抗体４の表面を覆う絶縁バリア層５と、複数の発熱抵抗体４の抵抗長方向の両端部に接続した導体６と、絶縁性耐磨耗保護層７とを備えている。蓄熱層３は、放熱性基板２の一端部側に位置して略半球面状をなす凸面段差部３ａと、この凸面段差部３ａの底部に連続して均一な膜厚を有する平坦部３ｂとにより形成された全面グレーズ層である。複数の発熱抵抗体４は、Ｔａ2Ｎ又はＴａ−ＳｉＯ2等で形成された抵抗体層４’の一部であり、蓄熱層３の凸面段差部３ａ上に、図１の紙面とは垂直な方向に微小間隔をあけて一列に配置されている。絶縁バリア層５は、例えばＳｉＯ2、ＳｉＯＮ、ＳｉＡｌＯＮ等の絶縁材料で形成されている。この絶縁バリア層５は、各発熱抵抗体４の表面を覆うことで、その平面的な大きさ（抵抗長、幅寸法）を規定する。導体６は、例えばＡｌ、Ａｕ、Ｃｕ、Ｃｒ、Ｔｉ、Ｎｉ、Ｗ等の導電材料からなり、発熱抵抗体４の抵抗長方向の一端側に位置して全ての発熱抵抗体４に共通に接続したコモン導体６Ａと、他端側に位置して各発熱抵抗体４に個別に接続した複数の個別導体６Ｂとを備えている。絶縁性耐磨耗保護層７は、印刷媒体との接触による摩擦等からヘッド基板１を保護する層である。この絶縁性耐磨耗保護層７は、ＳｉＯ2やＳｉＡｌＯＮ等の絶縁材料により、蓄熱層３、絶縁バリア層５及び導体６を含む基板表面に、回路基板２０側の端部を除いて、形成されている。 The head substrate 1 includes a heat-dissipating substrate 2 made of Si, a ceramic material, a metal material, etc., a heat storage layer 3 formed of a heat insulating material such as glass on the upper surface 2a of the heat-dissipating substrate 2, and a plurality of heat sources that generate heat when energized The heating resistor 4, the insulating barrier layer 5 covering the surface of each heating resistor 4, the conductor 6 connected to both ends in the resistance length direction of the plurality of heating resistors 4, the insulating wear-resistant protective layer 7, It has. The heat storage layer 3 includes a convex stepped portion 3a having a substantially hemispherical shape located on one end side of the heat dissipation substrate 2, and a flat portion 3b having a uniform film thickness continuously from the bottom of the convex stepped portion 3a. It is the whole surface glaze layer formed by. The plurality of heating resistors 4 are part of a resistor layer 4 ′ formed of Ta 2 N, Ta—SiO 2 or the like, and are perpendicular to the paper surface of FIG. 1 on the convex stepped portion 3 a of the heat storage layer 3. They are arranged in a row at small intervals in various directions. The insulating barrier layer 5 is formed of an insulating material such as SiO 2 , SiON, SiAlON, or the like. This insulating barrier layer 5 covers the surface of each heating resistor 4 to define its planar size (resistance length, width dimension). The conductor 6 is made of a conductive material such as Al, Au, Cu, Cr, Ti, Ni, and W, for example, and is located on one end side in the resistance length direction of the heating resistor 4 and commonly connected to all the heating resistors 4. Common conductor 6A, and a plurality of individual conductors 6B located on the other end side and individually connected to each heating resistor 4 are provided. The insulating wear-resistant protective layer 7 is a layer that protects the head substrate 1 from friction caused by contact with the print medium. This insulating wear-resistant protective layer 7 is formed of an insulating material such as SiO 2 or SiAlON on the substrate surface including the heat storage layer 3, the insulating barrier layer 5 and the conductor 6 except for the end on the circuit board 20 side. Has been.
一方、回路基板２０は、ヘッド基板１の複数の個別導体６Ｂを介して複数の発熱抵抗体４を選択的に通電する複数の駆動ＩＣ２１を備えている。この回路基板２０は、駆動ＩＣ２１の上面２１ａをヘッド基板１の上面１ａ（回路基板２０側に露出している導体上面）より下に位置させた状態で、ヘッド基板１に隣接して配置されている。 On the other hand, the circuit board 20 includes a plurality of drive ICs 21 that selectively energize the plurality of heating resistors 4 through the plurality of individual conductors 6B of the head substrate 1. The circuit board 20 is disposed adjacent to the head substrate 1 with the upper surface 21a of the driving IC 21 positioned below the upper surface 1a of the head substrate 1 (the upper surface of the conductor exposed on the circuit substrate 20 side). Yes.
上記全体構成を有するサーマルヘッドにおいて、対応する複数の個別導体６Ｂと複数の駆動ＩＣ２１は、Ａｕワイヤー３０を用いたワイヤーボンディングによりそれぞれ接続されている。Ａｕワイヤー３０は、線径１８〜２２μｍ程度のＡｕ導線であり、駆動ＩＣ２１に接続した一端部３０ａと、個別導体６Ｂに接続した他端部３０ｂと、ヘッド基板１の回路基板側の角部α上方に位置する折り曲げ部３０ｃとを有している。折り曲げ部３０ｃは、Ａｕワイヤー３０をヘッド基板１の角部αで折り曲げて形成したもので、該角部αに対応する角形状（非ループ形状）をなす。このＡｕワイヤー３０において、ワイヤー高さ（ヘッド基板上面１ａからの高さ）は、折り曲げ部３０ｃで最大となる。具体的に折り曲げ部３０ｃでのワイヤー高さは６０μｍ前後である。 In the thermal head having the overall configuration, the corresponding individual conductors 6 </ b> B and the plurality of driving ICs 21 are connected to each other by wire bonding using Au wires 30. The Au wire 30 is an Au conducting wire having a wire diameter of about 18 to 22 μm, one end 30a connected to the driving IC 21, the other end 30b connected to the individual conductor 6B, and a corner α on the circuit board side of the head substrate 1. And a bent portion 30c located above. The bent portion 30c is formed by bending the Au wire 30 at the corner portion α of the head substrate 1, and has a corner shape (non-loop shape) corresponding to the corner portion α. In the Au wire 30, the wire height (height from the head substrate upper surface 1a) is maximized at the bent portion 30c. Specifically, the wire height at the bent portion 30c is around 60 μm.
このＡｕワイヤー３０、個別導体６Ｂ及び駆動ＩＣ２１を含むボンディング部は、保護樹脂８により覆われている。保護樹脂８は、Ａｕワイヤー３０を完全に覆うのに必要な最小限の厚さで形成されており、この保護樹脂表面８ａは、複数の発熱抵抗体４（蓄熱層３の凸面段差部３ａの頂上部）よりも下に位置している。 The bonding portion including the Au wire 30, the individual conductor 6B, and the driving IC 21 is covered with the protective resin 8. The protective resin 8 is formed with a minimum thickness necessary to completely cover the Au wire 30, and the protective resin surface 8 a is formed of the plurality of heating resistors 4 (the convex stepped portions 3 a of the heat storage layer 3. It is located below (top).
次に、図２〜図６を参照し、本発明によるサーマルヘッドのワイヤーボンディング方法について説明する。 Next, the wire bonding method of the thermal head according to the present invention will be described with reference to FIGS.
先ず、ヘッド基板１と回路基板２０を、駆動ＩＣ２１の上面２１ａをヘッド基板１の上面１ａより下に位置させて、隣接配置する。 First, the head substrate 1 and the circuit substrate 20 are arranged adjacent to each other with the upper surface 21a of the drive IC 21 positioned below the upper surface 1a of the head substrate 1.
次に、図２に示すように、Ａｕワイヤー３０を挿通したキャピラリ４０を準備する。本実施形態で用いるキャピラリ４０は、Ａｕワイヤー３０を送出口４１へ導く挿通路４２を内蔵しており、挿通路４２に挿入したＡｕワイヤー３０の一端部３０ａを送出口４１から外方へ突出させた状態で保持する。Ａｕワイヤー３０の一端部３０ａは、ボンディング容易にするため、球状のＡｕボールにしておくことが好ましい。 Next, as shown in FIG. 2, a capillary 40 through which the Au wire 30 is inserted is prepared. The capillary 40 used in the present embodiment has a built-in insertion passage 42 that guides the Au wire 30 to the delivery port 41, and projects one end 30a of the Au wire 30 inserted into the insertion passage 42 outward from the delivery port 41. Hold in the state. One end 30a of the Au wire 30 is preferably a spherical Au ball in order to facilitate bonding.
続いて、図３に示すように、キャピラリ４０を用いて、Ａｕワイヤー３０の一端部３０ａと回路基板２０の駆動ＩＣ２１を超音波接合する。この超音波接合は、キャピラリ４０を駆動ＩＣ２１に押し当ててＡｕワイヤー３０の一端部３０ａを該駆動ＩＣ２１に密着させ、この密着状態で該一端部３０ａに超音波振動を与えることにより行う。超音波振動は、キャピラリ４０とは別に備えた超音波発振器から、あるいは、キャピラリ４０に接続した超音波発信器から該キャピラリ４０を介して、Ａｕワイヤー３０の一端部３０ａに与える。 Subsequently, as shown in FIG. 3, the capillary 40 is used to ultrasonically bond the one end 30 a of the Au wire 30 and the drive IC 21 of the circuit board 20. This ultrasonic bonding is performed by pressing the capillary 40 against the drive IC 21 so that the one end 30a of the Au wire 30 is brought into close contact with the drive IC 21 and applying ultrasonic vibration to the one end 30a in this tight contact state. The ultrasonic vibration is applied to one end 30 a of the Au wire 30 from an ultrasonic oscillator provided separately from the capillary 40 or from an ultrasonic transmitter connected to the capillary 40 through the capillary 40.
続いて、図４に示すように、駆動ＩＣ２１に接続したＡｕワイヤー３０の一端部３０ａ（第１接続点）からキャピラリ４０を真っ直ぐ上方へ持ち上げて、キャピラリ４０の送出口４１からＡｕワイヤー３０を繰り出す。Ａｕワイヤー３０の繰出量は、キャピラリ４０の上下方向の位置により調整可能である。本実施形態では、駆動ＩＣ２１からヘッド基板１の個別導体６Ｂ上の接続点（第２接続点）となる位置に達するのに必要な最小限の繰出量だけ、Ａｕワイヤー３０を繰り出す。 Next, as shown in FIG. 4, the capillary 40 is lifted straight up from one end 30 a (first connection point) of the Au wire 30 connected to the drive IC 21, and the Au wire 30 is fed out from the delivery port 41 of the capillary 40. . The feeding amount of the Au wire 30 can be adjusted by the vertical position of the capillary 40. In the present embodiment, the Au wire 30 is fed out from the driving IC 21 by a minimum amount of feeding necessary to reach a position that becomes a connection point (second connection point) on the individual conductor 6B of the head substrate 1.
続いて、駆動ＩＣ２１に接続したＡｕワイヤー３０の一端部３０ａを中心とする円弧軌道（図４に鎖線矢印で示す軌道）に沿ってキャピラリ４０をヘッド基板１側へ移動開始させ、この移動途中で、図５に示すように、Ａｕワイヤー３０をヘッド基板１の回路基板側の角部αに上方から打ち当てて折り曲げる。これにより、Ａｕワイヤー３０には、ヘッド基板１の角部αの上方に位置させて、該角部αに対応する角状の折り曲げ部３０ｃが形成される。この角状の折り曲げ部３０ｃによれば、駆動ＩＣ２１側にループ折り曲げ部１３０ｃ（図７（ｅ））のような膨らみが生じず、折り曲げ部３０ｃにおけるワイヤー高さ、すなわち、ワイヤー高さの最大値ｈmaxを可及的に低く抑えることができる。折り曲げ部３０ｃの形成後は続けて、キャピラリ４０を上記円弧軌道に沿ってヘッド基板１の個別導体６Ｂ上まで移動させる。 Subsequently, the capillary 40 is started to move toward the head substrate 1 along an arc trajectory (orbit indicated by a chain line arrow in FIG. 4) centering on one end 30a of the Au wire 30 connected to the drive IC 21, and in the middle of this movement As shown in FIG. 5, the Au wire 30 is hit against the corner α on the circuit board side of the head substrate 1 from above and bent. As a result, the Au wire 30 is formed with a corner-shaped bent portion 30c corresponding to the corner portion α so as to be positioned above the corner portion α of the head substrate 1. According to the square bent portion 30c, the bulge as in the loop bent portion 130c (FIG. 7E) does not occur on the drive IC 21 side, and the wire height in the bent portion 30c, that is, the maximum value of the wire height. hmax can be kept as low as possible. After the formation of the bent portion 30c, the capillary 40 is moved onto the individual conductor 6B of the head substrate 1 along the circular arc trajectory.
続いて、図６に示すように、キャピラリ４０を用いてＡｕワイヤー３０の他端部３０ｂとヘッド基板１の個別導体６Ｂを超音波接合する。 Subsequently, as shown in FIG. 6, the other end 30 b of the Au wire 30 and the individual conductor 6 B of the head substrate 1 are ultrasonically bonded using the capillary 40.
以上の工程により、ヘッド基板１の個別導体６Ｂと回路基板２０の駆動ＩＣ２１のワイヤーボンディングが完了し、後にＡｕワイヤー３０、個別導体６Ｂ及び駆動ＩＣ２１を含むボンディング部は保護樹脂８で覆われる。 Through the above steps, the wire bonding between the individual conductor 6B of the head substrate 1 and the drive IC 21 of the circuit board 20 is completed, and the bonding portion including the Au wire 30, the individual conductor 6B, and the drive IC 21 is later covered with the protective resin 8.
次に、ヘッド基板１の個別導体６Ｂと回路基板２０の駆動ＩＣ２１を、図２〜図６に示すワイヤーボンディング方法で接続した実施例と、図７に示すワイヤーボンディング方法で接続した比較例（従来例）を比較し、本発明の作用効果について説明する。実施例ではＡｕワイヤー３０に角状の折り曲げ部３０ｃが形成され、比較例ではＡｕワイヤー３０にループ形状のループ折り曲げ部１３０ｃが形成されている。 Next, an example in which the individual conductor 6B of the head substrate 1 and the drive IC 21 of the circuit board 20 are connected by the wire bonding method shown in FIGS. 2 to 6 and a comparative example in which the wire bonding method shown in FIG. Example) will be compared to explain the effects of the present invention. In the embodiment, a square bent portion 30 c is formed on the Au wire 30, and in the comparative example, a loop-shaped loop bent portion 130 c is formed on the Au wire 30.
表１及び表２は、上記実施例と比較例についてそれぞれ５つのサンプルＳ１〜Ｓ５、Ｓ６〜Ｓ１０を用意し、各サンプルのワイヤー高さの最大値ｈmaxを測定した結果を示す。ワイヤー高さの最大値ｈmaxは、通常、折り曲げ部３０ｃ、１３０ｃにおけるワイヤー高さとなる。 Tables 1 and 2 show the results of preparing five samples S1 to S5 and S6 to S10 for the above examples and comparative examples, respectively, and measuring the maximum value hmax of the wire height of each sample. The maximum value hmax of the wire height is usually the wire height at the bent portions 30c and 130c.
［表１］実施例
Ｎｏ． ｈmax（μｍ）
Ｓ１ ５８
Ｓ２ ６０
Ｓ３ ６５
Ｓ４ ５６
Ｓ５ ５８
[Table 1] Example No. hmax (μm)
S1 58
S2 60
S3 65
S4 56
S5 58
［表２］比較例
Ｎｏ． ｈmax（μｍ）
Ｓ６ １４０
Ｓ７ １３８
Ｓ８ １３５
Ｓ９ １３７
Ｓ１０ １４５
[Table 2] Comparative Example hmax (μm)
S6 140
S7 138
S8 135
S9 137
S10 145
表１及び表２を参照してワイヤー高さの最大値ｈmaxの平均値を算出してみると、実施例では５９．４μｍであるのに対し、比較例では１３９μｍであり、実施例によればワイヤー高さの最大値ｈmaxを比較例の約半分以下に低減できることが明らかである。このようにワイヤー高さｈmaxを低く抑えれば、ボンディング部を覆う保護樹脂８の表面高さも低く抑えることができ、この保護樹脂８の表面８ａを発熱抵抗体４よりも下に位置させることができる。これにより、ヘッド基板１のサイズが小さくなっても、保護樹脂８と印刷媒体が接触することを回避でき、印刷品質を良好に維持することが可能である。 When the average value of the maximum value hmax of the wire height is calculated with reference to Table 1 and Table 2, it is 59.4 μm in the example, whereas it is 139 μm in the comparative example. It is clear that the maximum value hmax of the wire height can be reduced to about half or less of the comparative example. If the wire height hmax is kept low in this way, the surface height of the protective resin 8 covering the bonding portion can be kept low, and the surface 8a of the protective resin 8 can be positioned below the heating resistor 4. it can. Thereby, even if the size of the head substrate 1 is reduced, it is possible to avoid contact between the protective resin 8 and the print medium, and it is possible to maintain good print quality.
以上では、ヘッド基板１の個別導体６Ｂと回路基板２０の駆動ＩＣ２１をＡｕワイヤーボンディングする実施形態について説明したが、本発明によるワイヤーボンディングは、回路基板２０に電源を設ける場合には、ヘッド基板１のコモン導体６Ａと回路基板２０の電源のワイヤーボンディングにも適用可能である。また本実施形態では、導体６がコモン導体６Ａと複数の個別導体６Ｂを有する直線電極構造で形成されているが、導体６は、隣り合う一対の発熱抵抗体を接続する折返導体と、この折返導体を介して一対の発熱抵抗体を通電するコモン導体及び個別導体とを有する折返電極構造で形成することも可能である。 In the above, the embodiment in which the individual conductor 6B of the head substrate 1 and the driving IC 21 of the circuit board 20 are Au wire bonded has been described. However, the wire bonding according to the present invention is performed when the circuit board 20 is provided with a power source. The common conductor 6A and the circuit board 20 can be applied to wire bonding of the power source. In this embodiment, the conductor 6 is formed in a linear electrode structure having a common conductor 6A and a plurality of individual conductors 6B. The conductor 6 includes a folded conductor that connects a pair of adjacent heating resistors, and the folded conductor. It is also possible to form a folded electrode structure having a common conductor and an individual conductor for energizing a pair of heating resistors through a conductor.
１ ヘッド基板
１ａ 上面
２ 放熱性基板
３ 蓄熱層（全面グレーズ層）
３ａ 凸面段差部
３ｂ 平坦部
４ 発熱抵抗体
５ 絶縁バリア層
６ 導体
６Ａ コモン導体
６Ｂ 個別導体
７ 絶縁性耐磨耗保護層
８ 保護樹脂
８ａ 保護樹脂表面
２０ 回路基板
２１ 駆動ＩＣ
２１ａ 上面
３０ Ａｕワイヤー
３０ａ 一端部
３０ｂ 他端部
３０ｃ 折り曲げ部
４０ キャピラリ
α 角部
ｈmax ワイヤー高さ（最大値）
1 Head substrate 1a Upper surface 2 Heat dissipation substrate 3 Thermal storage layer (entire glaze layer)
3a Convex step portion 3b Flat portion 4 Heating resistor 5 Insulating barrier layer 6 Conductor 6A Common conductor 6B Individual conductor 7 Insulating wear-resistant protective layer 8 Protective resin 8a Protective resin surface 20 Circuit board 21 Drive IC
21a upper surface 30 Au wire 30a one end 30b other end 30c bent part 40 capillary α corner hmax wire height (maximum value)
Claims (2)
前記ヘッド基板と前記回路基板は、該回路基板の駆動回路上面をヘッド基板上面より下に位置させた状態で隣接配置され、
前記Ａｕワイヤーは、前記ヘッド基板の回路基板側の角部の上方において、該ヘッド基板上面からの高さが最も高くなるように折り曲げて接続されていることを特徴とするサーマルヘッド。 A head substrate having a plurality of heating resistors and a conductor that is conductively connected to the plurality of heating resistors, and a circuit board on which a drive circuit that controls energization of the plurality of heating resistors is mounted. In a thermal head in which a conductor and a drive circuit of a circuit board are connected by an Au wire,
The head substrate and the circuit board are adjacently arranged in a state where the upper surface of the drive circuit of the circuit board is positioned below the upper surface of the head substrate,
The thermal wire is characterized in that the Au wire is bent and connected above the corner of the head substrate on the circuit board side so that the height from the upper surface of the head substrate is the highest.
前記ヘッド基板と前記回路基板を、該回路基板の駆動回路上面をヘッド基板上面より下に位置させて、隣接配置する工程；
Ａｕワイヤーを挿通したキャピラリを準備する工程；
このキャピラリを用いて前記回路基板の駆動回路にＡｕワイヤーの一端部を接続する工程；
この接続点から前記キャピラリを垂直に持ち上げ、前記Ａｕワイヤーを繰り出す工程；
前記接続点を中心とする円弧軌道に沿って前記キャピラリを前記ヘッド基板側へ移動させ、この移動中に、前記Ａｕワイヤーを前記ヘッド基板の回路基板側の角部に打ち当てて折り曲げる工程；及び
前記キャピラリを用いて前記ヘッド基板の導体に前記Ａｕワイヤーの他端部を接続する工程；
を有することを特徴とするサーマルヘッドのワイヤーボンディング方法。 In a thermal head comprising a plurality of heating resistors and a head substrate having a conductor conductively connected to the plurality of heating resistors, and a circuit board on which a drive circuit for controlling energization to the plurality of heating resistors is mounted, It is a method of connecting the conductor of this head substrate and the drive circuit of the circuit substrate by Au wire,
Placing the head substrate and the circuit board adjacent to each other with the upper surface of the drive circuit of the circuit board positioned below the upper surface of the head substrate;
Preparing a capillary through which an Au wire is inserted;
Connecting one end of the Au wire to the drive circuit of the circuit board using the capillary;
Lifting the capillary vertically from this connection point and feeding out the Au wire;
Moving the capillary toward the head substrate along an arc orbit centered on the connection point, and hitting and bending the Au wire against a corner of the head substrate on the circuit substrate side during the movement; and Connecting the other end of the Au wire to the conductor of the head substrate using the capillary;
A wire bonding method for a thermal head, comprising:
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| JP2019111751A (en) * | 2017-12-25 | 2019-07-11 | 東芝ホクト電子株式会社 | Thermal print head and thermal printer |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04241432A (en) * | 1991-01-14 | 1992-08-28 | Rohm Co Ltd | Wire bonding structure between semiconductor chip and substrate mounted with same |
| JPH1116934A (en) * | 1997-06-20 | 1999-01-22 | Fujitsu Ltd | Wire-bonding method |
-
2006
- 2006-09-08 JP JP2006244455A patent/JP2008062565A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04241432A (en) * | 1991-01-14 | 1992-08-28 | Rohm Co Ltd | Wire bonding structure between semiconductor chip and substrate mounted with same |
| JPH1116934A (en) * | 1997-06-20 | 1999-01-22 | Fujitsu Ltd | Wire-bonding method |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2019111751A (en) * | 2017-12-25 | 2019-07-11 | 東芝ホクト電子株式会社 | Thermal print head and thermal printer |
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