JPS63128195A - Method and device for partial plating - Google Patents

Abstract

PURPOSE:To partially plate a minute area with high positional precision and at high speed by pressing a masking member on a material to be plated, and making the internal pressure due to the plating soln. in the vicinity of the opening of the parallel flow passage of the member lower than the external pressure exerted on the face of the material not to be plated. CONSTITUTION:The material 3 to be plated is interposed between a masking member 1, having an opening 4 for determining the shape of the face to be plated and the parallel flow passage 12 of the plating soln. parallel to the face to be plated and communicating with the opening 4, and a retaining plate 7, and plated through the opening 4. In this case, the pressure in a first chamber 8 of a pressure box 2 holding the member 1 is made lower than the specified atmospheric pressure, the pressure in a second chamber 9 is kept lower than the pressure in the first chamber 8, and the pressure in the vicinity of the opening 4 of the parallel flow passage 12 is kept lower than the atmospheric pressure by 0.15kgf/cm<2>. The material 3 to be plated is sucked and closely attached to the surface 1a of the masking member 1 due to the pressure difference between the negative pressure of the plating soln. in the vicinity of the opening 4 and the external air (atmosphere), hence the oozing out of the plating soln. is prevented, and an excellent plating boundary can be obtained.

Description

【発明の詳細な説明】 〈産業上の利用分野〉 本発明は、ｔＣリードフレーム等のめっき処理をすべき
材料の微小な部分のみにめっき処理をするための部分め
っき法およびその装置に関する。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a partial plating method and apparatus for plating only a minute portion of a material to be plated, such as a tC lead frame.

〈従来技術およびその問題点〉 ＩＣ等に用いられるリードフレームは、シリコンチップ
を搭載するタブ部やリード部先端（インナリード部）の
ボンディング部にワイヤボンディングのために金、銀な
どの貴金属めっきが施されているが、近年の金、銀の価
格高騰に伴ない、これらのめっき面積の微小化が進んで
いる。ことにリードフレームが樹脂封止型においては、
前記貴金属めっきが銀めっきの場合、封止樹脂の外部に
露出するアウタリード部までが銀めっきを施されている
と、いわゆるマイグレーションにより短絡事故を誘起し
、ＩＣの信頼性が著しく損なわれる。従って、めっき面
積の微小化と共に、めフきにじみ出しのない、高位置精
度なめっきが強く望まれている。<Prior art and its problems> Lead frames used for ICs, etc. are plated with precious metals such as gold and silver for wire bonding on the tab portion on which the silicon chip is mounted and the bonding portion of the lead tip (inner lead portion). However, as the prices of gold and silver have soared in recent years, the area of these platings has become smaller. Especially when the lead frame is resin-sealed,
When the noble metal plating is silver plating, if the silver plating is applied to the outer lead portion exposed to the outside of the sealing resin, a short circuit accident will be induced due to so-called migration, and the reliability of the IC will be significantly impaired. Therefore, there is a strong demand for miniaturization of the plating area and for plating with high positional accuracy without bleed-through.

従来、リードフレームへの部分めっきは、第８ａ図に示
すようにリードフレーム３のめっきを必要とする部分に
対応させて開孔４を設けたゴム等の軟質材からなるマス
キング部材１をリードフレーム３に押し当て、このめっ
き面に向けて、ノズル３０によりめっき液のジェット流
３１を吹き付けて、高速化を図りながらめっきを行うも
のが多い。この場合、ジェット流３１がめつき面に衝突
することにより、めっき面上においてめっき液圧力が高
くなり、このためにマスク開孔４を通ｑてめっき液３１
がめつき部より外部へにじみ出し、めっき不要部分にま
でめっきがなされ、めっき位置精度が低下するという問
題があった。Conventionally, partial plating on a lead frame has been carried out using a masking member 1 made of a soft material such as rubber, which has openings 4 corresponding to the parts of the lead frame 3 that require plating, as shown in FIG. 8a. 3, and a jet stream 31 of plating solution is sprayed from a nozzle 30 toward this plating surface to perform plating while increasing the speed. In this case, the jet stream 31 collides with the plating surface, increasing the plating solution pressure on the plating surface, and therefore the plating solution 31 passes through the mask opening 4 q.
There was a problem in that the plating seeped out from the plating area, plating was applied to areas that did not require plating, and the accuracy of plating position was reduced.

ここで、めっき面積が比較的大きい場合、即ちマスク開
孔４が比較的大きい場合は、マスク開孔４内にめっき液
３１の排除空間３２が確保される（第８ａ図参照）が、
近年のめっき面積の微小化に伴ない、第８ｂ図に示すよ
うにマスク開孔４も微小化され、このため、この開孔４
に向ってジェット流を吹き付けても、めっき部近傍での
めっき液の高速流動は期待できず、したがってめっき吹
き付は速度がそれほど高速化されないことがあげられる
。また、この場合、ノズル３０も微細化し、かつノズル
３０とマスク開孔４の位置合わせを厳密に行わない限り
、第８ｂ図に示すように、開孔４内にめっき液３１が淀
み、高速流とはならない。Here, when the plating area is relatively large, that is, when the mask aperture 4 is relatively large, an exclusion space 32 for the plating solution 31 is secured within the mask aperture 4 (see FIG. 8a).
As the plating area has become smaller in recent years, the mask opening 4 has also become smaller as shown in FIG. 8b.
Even if a jet stream is sprayed toward the plating area, high-speed flow of the plating solution near the plating area cannot be expected, and therefore, the speed of plating spraying will not be increased that much. In this case, unless the nozzle 30 is also miniaturized and the nozzle 30 and the mask aperture 4 are precisely aligned, the plating solution 31 will stagnate in the aperture 4 and the high-speed flow It is not.

ｍ＝・方でＩＣリードフレームのリード部はますます微
細化する傾向にあり、多数のリード先端部に対して微小
なマスク開孔と、微細なノズルの位置合わせを厳密に行
うことは実際には非常に困難であり、高速化が達成され
ないばかりでなく、各リード部でのめっき面における液
流動様態が一定せず、結晶粒、めりき厚さ等のめっき品
質にばらつきを生じるという大きな問題点を生じている
。In the direction of m=・, the lead parts of IC lead frames tend to become increasingly finer, and it is actually difficult to precisely align the minute mask holes and the minute nozzles for the tips of many leads. This is extremely difficult, and not only does it fail to achieve high speeds, but the liquid flow pattern on the plating surface of each lead is not consistent, leading to variations in plating quality such as crystal grains and plating thickness, which is a major problem. points are occurring.

これらの問題点に対しては、例えば特開昭５５−３８９
５４号あるいは特開昭５７−９８９４号に開示されてい
るように、めっき面に対してめフき液を垂直噴射するの
ではなく、比較的平行な流れを得ようとするものがある
。しかしこれらは平行流という意味からは不完全なもの
である他に、次のような欠点を有している。For these problems, for example, Japanese Patent Application Laid-Open No. 55-389
As disclosed in No. 54 or Japanese Patent Application Laid-open No. 57-9894, there is a technique that attempts to obtain a relatively parallel flow of the cleaning liquid instead of injecting it perpendicularly to the plating surface. However, in addition to being incomplete in terms of parallel flow, these methods also have the following drawbacks.

すなわち前者は、波形の長い液流路の頂部に開孔を設け
て部分めっきを行うものであるが、流路内の波状凹凸の
ために流体抵抗が大きくなり、この圧力損失のために、
流路入口側の液の圧力が出口側よりも著しく高くなり、
入口側付近において垂直噴射めっきの場合と同様にマス
ク開孔からの液のにじみ出しが大きく、めっき位置精度
の低下を防止できない。In other words, in the former method, partial plating is performed by providing an opening at the top of a long corrugated liquid flow path, but the wave-like unevenness in the flow path increases fluid resistance, and this pressure loss causes
The pressure of the liquid on the inlet side of the channel becomes significantly higher than that on the outlet side,
Similar to the case of vertical spray plating, liquid oozes out from the mask openings near the entrance side, making it impossible to prevent a decrease in plating position accuracy.

また後者は、マスキング治具からの液のにしみ出し防止
に対しては、可塑性物体によるシール効果および溶液を
噴射させないこと、すなわち液を高速に流動させないこ
とにより実現するものであり、めっきの高速化という点
では大きな欠点を存している。The latter is achieved by preventing the liquid from seeping out from the masking jig by using a sealing effect using a plastic object and by not spraying the solution, that is, by not allowing the liquid to flow at high speed. There are major drawbacks in terms of compatibility.

他の公知例としては、例えば特開昭５５−３１１６８号
あるいは特開昭５２−７４５３６号のように、外気をマ
スク開孔を通してめっき源側に吹き付けまたは吸引する
ことによりめっき液のにじみ出しを防止しようとする試
みがある。しかしこの場合、吸引された気体がめつき液
中に混入し、あるいはめっき液の流れを阻害し、めっき
液のめっき面への安定正常な到達を妨げ、その結果、め
っき結晶組織、めっき厚さ等のめっき品質の不安定化を
招くという問題点があった。Other known examples include, for example, JP-A-55-31168 or JP-A-52-74,536, which prevents the plating solution from seeping out by blowing or suctioning outside air toward the plating source through the mask openings. There are attempts to do so. However, in this case, the sucked gas mixes into the plating solution or obstructs the flow of the plating solution, preventing the plating solution from reaching the plating surface in a stable and normal manner.As a result, the plating crystal structure, plating thickness, etc. There was a problem that the plating quality became unstable.

〈発明の目的〉 本発明は上記事情に鑑みてなされたもので、上述した従
来技術の欠点を解消し、にじみ出しがなく、したがって
高位置精度のかつ高速な微小面ｈ１への部分めっきを可
能にする部分めっき法およびその装置を提供することを
目的とする。<Object of the Invention> The present invention has been made in view of the above circumstances, and eliminates the drawbacks of the above-mentioned prior art, eliminates bleeding, and therefore enables high-speed partial plating on the microscopic surface h1 with high positional accuracy. The purpose of the present invention is to provide a partial plating method and an apparatus for the same.

〈発明の構成〉 本発明の第１の態様によれば、被めっき材に、めっき面
形状を決定する開孔と、該開孔に連通しかつ前記めっき
面に平行に形成された平行流通路とを有するマスキング
部材を押し当て、該平行流通路内に供給されためっき液
にて前記開孔を介して部分めっきを行うに際し、前記被
めっき材の非めっき面にかかる外圧に対し、前記平行流
通路の開孔近傍のめっき液により前記被めっき材のめっ
き面にかかる内圧を０．！５Ｋｇｆ／ｃ＋＋＋２以上低
圧にすることを特徴とする部分めっき法が提供される。<Structure of the Invention> According to the first aspect of the present invention, the material to be plated has an opening that determines the shape of the plating surface, and a parallel flow path that is connected to the opening and is formed parallel to the plating surface. When applying a masking member having a masking member and performing partial plating through the opening with the plating solution supplied into the parallel flow path, The internal pressure applied to the plating surface of the material to be plated by the plating solution near the opening of the flow path is reduced to 0. ! A partial plating method is provided which is characterized in that the pressure is lower than 5Kgf/c++2.

本発明の第２の態様によれば、被めっき材のめっき面形
状を決定する開孔と該開孔に連通しかつ前記めっき面に
平行に形成された平行流通路とを有するマスキング部材
と、めっき液を前記平行流通路内に送り込むめっき線駆
動手段と、前記被めっき材を前記マスキング部材に対し
て押圧する押圧手段とを存し、前記めっき線駆動手段に
より、被めっき材の非めっき面にかかる外圧に対し、首
記平行流通路の開孔近傍のめっき液により前記被めっき
材のめっき面にかかる内圧が０．１５Ｋｇｆ／ｃｒｎ２
以上低圧に保たれるよう構成してなることを特徴とする
部分めっき装置が提供される。According to a second aspect of the present invention, a masking member having an aperture that determines the shape of a plating surface of a material to be plated, and a parallel flow path communicating with the aperture and formed parallel to the plating surface; The plating line drive means includes a plating line drive means for feeding a plating solution into the parallel flow path, and a pressing means for pressing the material to be plated against the masking member. The internal pressure applied to the plating surface of the plated material by the plating solution near the opening of the parallel flow path is 0.15 Kgf/crn2.
There is provided a partial plating apparatus characterized in that the pressure is maintained at a low pressure.

本発明の第３の態様によれば、被めっき材のめっき面形
状を決定する開孔と該開孔に連通しかつ前記めっき面に
平行に形成された平行流通路とを有するマスキング部材
と、めっき液を前記平行流通路内に送り込むめっき線駆
動手段と、前記被めっき材を前記マスキング部材に対し
て押圧する押圧手段と、前記被めっき材の非めっき面を
加圧する気体加圧手段とを有し、前記めっき線駆動手段
および気体加圧手段により、被めっき材にかかる外圧に
対し、前記平行流通路の開孔近傍のめっき液により前記
被めっき材のめっき面にかかる内圧か０．１５Ｋｇｆ／
ｃｍ２以上低圧に保たれるよう構成してなることを特徴
とする部分めっき装置が提供される。According to a third aspect of the present invention, a masking member having an aperture that determines the shape of a plating surface of a material to be plated, and a parallel flow path communicating with the aperture and formed parallel to the plating surface; A plating line driving means for feeding a plating solution into the parallel flow path, a pressing means for pressing the material to be plated against the masking member, and a gas pressurizing means for pressurizing a non-plated surface of the material to be plated. The plating line driving means and gas pressurizing means reduce the internal pressure applied to the plating surface of the plating material by the plating solution near the opening of the parallel flow path to 0.15 Kgf relative to the external pressure applied to the plating material. /
A partial plating apparatus is provided, which is configured to maintain a pressure lower than cm2.

ここで、前記第２．３の態様においては、前記めっき線
駆動手段は、駆動ポンプおよびまたはアスピレータであ
るのが好ましい。Here, in the above-mentioned aspect 2.3, it is preferable that the plating line driving means is a driving pump and/or an aspirator.

また、ｎｆ記第２．３の態様においては、前記平行流通
路の長さを１、流通路高さをｄ、該平行流通路のめっき
液流速をＶとするとき、ｖ≧１０ｏｎ／ｓにおいてｌ／
ｄ≦４で、ｖ＜１０ｍ／ｓにおいてＪ２／ｄ≦１５を満
足するのが好ましい。In addition, in the aspect of No. 2.3 of NF, when the length of the parallel flow path is 1, the height of the flow path is d, and the flow rate of the plating solution in the parallel flow path is V, when v≧10 on/s, l/
It is preferable to satisfy J2/d≦15 when d≦4 and v<10 m/s.

以下、本発明を好適実施例に基づいて説明する。The present invention will be explained below based on preferred embodiments.

第１図は本発明に適用される部分めっき装置の断面図を
示し、該部分めっき装置は、圧力′Ａ２上に載置され開
孔４を有するマスキング部材ｌと、押さえ板７との間に
、被めっき材３を介在させ、前記開孔４を介して被めっ
き材３にめっきを施すようになっている。FIG. 1 shows a sectional view of a partial plating apparatus applied to the present invention, in which a masking member l placed on pressure 'A2 and having an opening 4 and a holding plate 7 are disposed. , the material to be plated 3 is interposed, and the material to be plated 3 is plated through the opening 4.

圧力箱２は第１室８と第２室９とに分かれており、第１
室８はパイプ１８を介してめっき線駆動手段の駆動ポン
プに、第２室９はバイブ１９を介してめっき線駆動手段
のアスピレータ（共に図示せず）にそれぞれ連通され、
めっき時には、首記駆動ポンプを駆動して第１室８内を
所定の大気圧より低い圧力に保ち、かつ第２室９内の圧
力をアスピレータを駆動させることにより第１室よりも
負圧に保つようになされており、これにより、後述する
マスキング部材１内部の平行流通路１２の開孔４付近く
めっき面付近）の圧力も大気圧よりも負圧に保たれるよ
うになっている。The pressure box 2 is divided into a first chamber 8 and a second chamber 9.
The chamber 8 is communicated with a drive pump of the plating wire drive means via a pipe 18, and the second chamber 9 is communicated with an aspirator (both not shown) of the plating wire drive means via a vibrator 19.
During plating, the drive pump described above is driven to maintain the pressure in the first chamber 8 lower than a predetermined atmospheric pressure, and the pressure in the second chamber 9 is lowered to a negative pressure than the first chamber by driving an aspirator. As a result, the pressure inside the masking member 1 (near the opening 4 of the parallel flow path 12 (near the plating surface)) is also maintained at a negative pressure rather than atmospheric pressure.

また、この第１室８はめっき液供給装置に、第２室９は
めっき液回収装置（共に図示せず）にそれぞれ別途、連
通している。めっき液は第１室８および第２室９の間を
循環していてもよい。Further, the first chamber 8 communicates with a plating solution supply device, and the second chamber 9 communicates with a plating solution recovery device (both not shown). The plating solution may be circulated between the first chamber 8 and the second chamber 9.

マスキング部材１の内部には、一端が圧力箱２の第１室
８に、他端が同第２室９にそれぞれ連通するめっき液流
通路（以下単に液流通路という）１０が形成されている
。Inside the masking member 1, a plating solution flow path (hereinafter simply referred to as a liquid flow path) 10 is formed, which communicates with the first chamber 8 of the pressure box 2 at one end and the second chamber 9 at the other end. .

液流通路ＩＯの途中部分は、マスキング部材表面１ａに
平行に形成された流通路（以下平行流通路という）１２
をなす。そしてこの平行流通路１２は、所定箇所にて、
マスキング部材表面１ａに対し垂直に穿設されて被めっ
き材３のめっき面を形成する開孔４に連通している。An intermediate portion of the liquid flow path IO is a flow path (hereinafter referred to as a parallel flow path) 12 formed parallel to the masking member surface 1a.
to do. This parallel flow path 12 has a predetermined location.
It communicates with an opening 4 that is perpendicular to the masking member surface 1a and forms the plating surface of the material to be plated 3.

液流通路１０によって形成される略台形状の台座部１３
上には、前記開孔部４対向部に電極（陽Ｖｉ）１１が表
面を露出して埋設されている。A substantially trapezoidal pedestal portion 13 formed by the liquid flow path 10
Above, an electrode (positive Vi) 11 is buried in a portion facing the opening 4 with its surface exposed.

そして、めフき時には、陽極と被めっき材（陰極）３と
の間に電圧を加えると共に、図示しないめっき液供給装
置から第１室８に供給されためっき液を、液流通路１０
を経て第２室９へと送液中に、平行流通路１２から開孔
４を介して被めっき材３のめっき面にめっきを施すよう
になっている。At the time of plating, a voltage is applied between the anode and the material to be plated (cathode) 3, and the plating solution supplied from the plating solution supply device (not shown) to the first chamber 8 is passed through the solution flow path 10.
While the liquid is being sent to the second chamber 9 via the parallel flow passage 12 through the opening 4, the plating surface of the material to be plated 3 is plated.

ここで、館述のように、第１室８は所定の大気圧より低
い圧力に、第２室９は第１室８よりも負圧に保たれるか
、これら二室に連通ずる液流通路１０内もその影響を受
け、平行流通路１２の開孔４近傍（めっき部近傍）も大
気圧に対して０．１５Ｋｇｆ／ｃｔｎ２以上負圧に保た
れる。このように、めっき部近傍のめっき液の負圧と外
気（大気）との０．１５Ｋｇｆ／ｃｍ２以上の圧力差に
より被めっき材３はマスキング部材表面１ａに吸引密着
され、これによりシール性が向上し、めっき液のにじみ
出しが防止され、良好なめっき境界が得られる。餌記圧
力差ヲ０．１５Ｋｇｆ／ｃｍ２以上トシタノハ、Ｏ，１
５Ｋｇｆ／ｃｍ２未満ではめっき液の毛管現象あるいは
液の流れにより生じる局部的な動圧による圧力上昇によ
り、めっき液のにじみを生じるからである。また、′ｌ
＆流通路１０内に圧力差が生ずることにより、内部を流
れるめっき液流の高速化が図れる。Here, as described in the museum, the first chamber 8 is kept at a pressure lower than a predetermined atmospheric pressure, and the second chamber 9 is kept at a more negative pressure than the first chamber 8, or the liquid flow communicates with these two chambers. The inside of the passage 10 is also affected by this, and the vicinity of the opening 4 (near the plating part) of the parallel flow passage 12 is also maintained at a negative pressure of 0.15 Kgf/ctn2 or more with respect to atmospheric pressure. In this way, the material to be plated 3 is suctioned into close contact with the masking member surface 1a due to the pressure difference of 0.15 Kgf/cm2 or more between the negative pressure of the plating solution near the plating part and the outside air (atmosphere), thereby improving sealing performance. This prevents the plating solution from bleeding out and provides a good plating border. Bait record pressure difference 0.15Kgf/cm2 or more Toshita Noha, O,1
This is because if it is less than 5 Kgf/cm2, the plating solution will smear due to the capillarity of the plating solution or the pressure increase due to local dynamic pressure caused by the flow of the plating solution. Also, 'l
& By creating a pressure difference within the flow path 10, the flow rate of the plating solution flowing therein can be increased.

また、平行流通路１２を設けることにより、前記めっき
液の高速化が減速されることなく、開孔４近傍すなわち
めっき部近傍にめっき液が供給されるため、効率のよい
めっきが行える。Further, by providing the parallel flow passage 12, the plating solution is supplied near the opening 4, that is, near the plating portion, without slowing down the speed increase of the plating solution, so that efficient plating can be performed.

なお、平行流通路１２を実質的にめフき面と平行に構成
するためには、マスキング部材表面１ａと平行流通路１
２との距１ａ　ｈ　ｌはできるだけ短い方が良く、した
がってマスキング部材材質には、強度の高いセラミック
もしくは絶縁コートを施した金属材料が好ましいが、硬
質塩化ビニル、高分子量ポリエチレン等の樹脂材料も使
用可能である。Note that in order to configure the parallel flow passage 12 substantially parallel to the mesh surface, it is necessary to align the masking member surface 1a and the parallel flow passage 1
It is better to have the distance 1a h l between 2 and 2 as short as possible. Therefore, the material of the masking member is preferably a high-strength ceramic or a metal material with an insulating coating, but resin materials such as hard vinyl chloride and high molecular weight polyethylene can also be used. It is possible.

また、マスキング部材１の表層部１５のみを軟質材にて
形成してもよく、こうすれば被めっき材３との密着性が
向上し、シール効果が高められ、めっきのにじみ等がよ
り効果的に防止できるので好都合であるが、この軟質材
はできるだけ薄層であるのがよい。軟質材としては耐薬
品性などの点からシリコンゴム、ウレタンゴム、軟質塩
化ビニル等の軟質樹脂を用いることができる。Further, only the surface layer 15 of the masking member 1 may be formed of a soft material, and in this way, the adhesion with the plated material 3 is improved, the sealing effect is enhanced, and bleeding of the plating is more effectively prevented. It is advantageous that this soft material is as thin a layer as possible because it can prevent this from occurring. As the soft material, soft resins such as silicone rubber, urethane rubber, and soft vinyl chloride can be used from the viewpoint of chemical resistance.

前記被めっき材３上に載置される押さえ板（押圧部材）
７は、エアシリンダ１４にて押圧され、このエアシリン
ダ１４の押圧力と面記平行流通路１２の負圧力とによっ
て被めっき材３をマスキング部材１と押さえ板７との間
に押圧固定するようになっている。A pressing plate (pressing member) placed on the plated material 3
7 is pressed by an air cylinder 14, and the material to be plated 3 is pressed and fixed between the masking member 1 and the holding plate 7 by the pressing force of the air cylinder 14 and the negative pressure of the parallel flow passage 12. It has become.

ここで、押さえ板７の、被めっき材３との接触面を軟質
部材５にて形成し、エアシリンダ１４との接触面を硬質
部材６にて形成することにより、被めっき材３との密着
性が向トしてシール効果が高められ、めっき精度が向上
する一方、エアシリンダ１４の押圧に対する耐久性も向
−ヒする。Here, by forming the contact surface of the holding plate 7 with the material 3 to be plated with the soft member 5 and the contact surface with the air cylinder 14 with the hard member 6, close contact with the material 3 to be plated is achieved. The sealing effect is improved and the plating accuracy is improved, while the durability against the pressure of the air cylinder 14 is also improved.

なお、押さえ板７の硬質部５の材質は、マスキング部材
１とほぼ同様な材質か使用できる。The hard portion 5 of the holding plate 7 may be made of substantially the same material as the masking member 1.

第２図は、被めっき材がリードフレーム材のような打抜
部（間隙部）を有する場合の実施態様を示し、第１図と
同一・部分は同一符号を付してその説明を省略する。Figure 2 shows an embodiment in which the material to be plated has a punched part (gap part) like a lead frame material, and the same parts as in Figure 1 are given the same symbols and their explanations are omitted. .

本実施態様では、被めっき材３の打抜部（間隙部）３ａ
に合わせて、押さえ板７の軟質部材５にあらかじめ凸部
５ａをモールド成型し、この凸部を被めっき材３の打抜
部３ａに嵌合させて、めっき位置粒度を高めている。さ
らに、マスキング部材１、被めっき材３および押さえ板
７はパイロットピン２０であらかじめ位置合わせされ、
これによりさらにめっき位置精度を高めることができる
。In this embodiment, a punched part (gap part) 3a of the material to be plated 3
In accordance with this, a convex portion 5a is molded in advance on the soft member 5 of the holding plate 7, and this convex portion is fitted into the punched portion 3a of the material to be plated 3 to increase the particle size of the plating position. Furthermore, the masking member 1, the material to be plated 3, and the holding plate 7 are aligned in advance with pilot pins 20,
This allows the plating position accuracy to be further improved.

液流通路１０内を押さえ板７外部に対して負圧に保つ手
段として、本実施態様のように、押さえ板７をバイブ２
５にて図示しない圧力調整装置に連通ずる加圧箱（気体
加圧手段）１６にて気密に覆い、加圧箱１６内の圧力を
大気圧（すなわち液流通路１０内の圧力）よりも高め、
相対的に液流通路１０を負圧にしてもよい。この場合、
押さえ板７には被めっき材３の所定箇所と加圧′Ａ１６
内とを連通ずる連通路２１を形成して、＋ｉｆ記加圧箱
１６内の圧力が被めっき材３にかがるようにする。こう
することにより、被めっき材３がマスキング部材ｌ上に
均一に押圧密着され、シール性が向−ヒし、良好なめっ
き境界部が得られる。As a means for keeping the inside of the liquid flow passage 10 at a negative pressure with respect to the outside of the presser plate 7, the presser plate 7 is connected to the vibrator 2 as in this embodiment.
5, it is airtightly covered with a pressurizing box (gas pressurizing means) 16 that communicates with a pressure regulator (not shown), and the pressure inside the pressurizing box 16 is made higher than atmospheric pressure (that is, the pressure inside the liquid flow passage 10). ,
The pressure in the liquid flow path 10 may be relatively negative. in this case,
The presser plate 7 holds a predetermined portion of the material to be plated 3 and pressurizes 'A16.
A communication path 21 is formed to communicate with the inside so that the pressure inside the pressurizing box 16 is applied to the material 3 to be plated. By doing so, the material to be plated 3 is uniformly pressed and adhered to the masking member 1, the sealing performance is improved, and a good plating boundary is obtained.

なお、加圧箱１６内には空気以外に、例えば窒素ガス、
アルゴンガスのような不活性な気体を導入してもよい。Note that, in addition to air, the pressurized box 16 contains, for example, nitrogen gas,
An inert gas such as argon gas may also be introduced.

図中符号２２はＯリングで、加圧箱１６内を気密にシー
ルしている。Reference numeral 22 in the figure is an O-ring that airtightly seals the inside of the pressurizing box 16.

すなわち、本発明では、めっき液のにじみ出しを防止す
る手段として、マスキング部材ｊおよび押さえ板７の少
なくとも−・方が軟質部材にて被めっき材３に接触する
ようにし、これらで被めっき材３を挟持することにより
、めっき液および外気のシールを行うこと、および押さ
え板７外部の圧力をマスキング部材１内部すなわち液流
通路１０内の圧力よりも高く保つことの二重の手段を講
じている。That is, in the present invention, as a means to prevent the plating solution from seeping out, at least one of the masking member j and the presser plate 7 is made to contact the material to be plated 3 with a soft member, and the material to be plated is By sandwiching the masking member 1, a double measure is taken to seal the plating solution and the outside air, and to maintain the pressure outside the presser plate 7 higher than the pressure inside the masking member 1, that is, the pressure inside the liquid flow passage 10. .

このような圧力差を設ける。テ）は、以下の理由による
。すなわち、第２図に・ｊ・−・−５′にうに、特に間
隙を有する被めっき材の場合、・ｉ’に’ｉ１材により
液シールを行おうとする際にもめっき部近傍でマスキン
グ部材１と押さえ板７の境目等にわずかな隙間を生じる
ことは現実には避けることができない。このようなわず
かな隙間に、めっき液は毛管作用により侵入する。Provide such a pressure difference. TE) is due to the following reasons. In other words, as shown in Figure 2, in the case of a material to be plated that has a gap, especially in the case of a material to be plated that has a gap, the masking member is used near the plating part when trying to seal the liquid with i1 material in i'. In reality, it is unavoidable that a slight gap will be created at the boundary between 1 and the holding plate 7. The plating solution enters into such a small gap by capillary action.

周知のように毛管力は、隙間が狭いほどその力を増し、
より深く侵入することになり、軟質材のみによる液シー
ルは困難である。この場合に、外気の圧力を液態の圧力
より高く保つ手段を併用することにより液が侵入する程
度の隙間に対しては容易に気体の圧力差の効果を及ぼす
ことができることから、液の毛管力に打ち勝つ程度の圧
力差を与えておけば、気体の巻き込みを伴なうことなく
液のにじみ出しを防ぐことができる。As is well known, the narrower the gap, the stronger the capillary force becomes.
Since the liquid penetrates deeper, it is difficult to seal the liquid with only soft material. In this case, by using a means to maintain the pressure of the outside air higher than the pressure of the liquid state, the effect of the gas pressure difference can be easily exerted on the gap where the liquid can enter, so the capillary force of the liquid By applying a pressure difference that overcomes the pressure difference, it is possible to prevent liquid from seeping out without entraining gas.

圧力差の発生は、外気を大気圧に、液態をそれよりも負
圧にしてもよく（第１図参照）、また外気を空気、窒素
ガス等のめっきに５１２　ｑを及ぼさない加圧気体とし
、液態を略大気圧としても良い（第２図参照）。またこ
れらを併用してもさしつかえない。To generate a pressure difference, the outside air may be brought to atmospheric pressure and the liquid state to a more negative pressure (see Figure 1), or the outside air may be a pressurized gas that does not affect the plating, such as air or nitrogen gas. , the liquid state may be at approximately atmospheric pressure (see Figure 2). It is also possible to use these in combination.

次に平行流通路１２については、マスキング部材１が複
数の開孔４を持つ場合等は、液流通路の摩擦抵抗による
入口側と出口側の圧力差が大きいと、前述のように高圧
側で液のにじみ出しの問題を生じる。Next, regarding the parallel flow passage 12, in cases where the masking member 1 has a plurality of holes 4, etc., if the pressure difference between the inlet side and the outlet side due to frictional resistance of the liquid flow passage is large, the high pressure side This causes problems with liquid oozing out.

すなわち、第２図において、平行流通路１２の長さ２の
間の圧力降下（圧力差）ΔＰは、流路形状等で決る摩擦
損失係数え、流速■、流路高さｄなどにより次の式で示
される。In other words, in Fig. 2, the pressure drop (pressure difference) ΔP between the length 2 of the parallel flow passage 12 is determined by the friction loss coefficient determined by the flow passage shape, etc., the flow velocity ■, the flow passage height d, etc. as follows. It is shown by the formula.

ｒは液の比重■、ｇは重力の加速度である。r is the specific gravity of the liquid, and g is the acceleration of gravity.

ここで圧力差△Ｐを小さくするには、λ、Ｖ等を一定と
考えれば、Ｉｌ／ｄを小さくすれば良い。Here, in order to reduce the pressure difference ΔP, assuming that λ, V, etc. are constant, Il/d may be reduced.

一般に、△Ｐ　＜　０．Ｉ　Ｋｇｆ／ｃｍ２程度で良好
な結果が得られることから逆算すると、ｖ≧１０ｍ／ｓ
であれば１／ｄ≦４が好ましく、ｖ＜１０ｍ／ｓでは１
／ｄ≦１５程度でも特に問題を生じない。In general, ΔP < 0. Good results can be obtained at around I Kgf/cm2, so if you calculate backwards, v≧10m/s
If so, 1/d≦4 is preferable, and if v<10m/s, 1/d≦4 is preferable.
Even when /d≦15, no particular problem occurs.

上記関係は、第２図においてのみならず、第１図に示す
ように開孔４が１個の場合にも適用され得る。The above relationship can be applied not only to the case of FIG. 2 but also to the case where there is one opening 4 as shown in FIG. 1.

なお流通路内に配置される電極１１は、ごく薄い箔を用
いるか、もしくは厚い板または撚線状の場合は表面のみ
を露出して流路内に埋め込み配置するのが、流路の圧力
損失を減じるので好ましい。Note that the electrode 11 placed in the flow path should be made of very thin foil, or if it is a thick plate or stranded wire, it should be embedded in the flow path with only the surface exposed, to reduce pressure loss in the flow path. This is preferable because it reduces

〈実施例〉 次に、本発明を実施例に基づいて更に詳細に説明する。<Example> Next, the present invention will be explained in more detail based on examples.

［実施例１］ 第１図のめっき装置において、マスキング部材１をアク
リル樹脂、押さえ板７の軟質部材５をシリコンゴム、硬
質部材６をアクリル樹脂にてそれぞれ製造し、Ｌ述した
要領で電極（陽極）１１と被めっき材（陰極）３との間
に電圧を加え、銀めっきを行った。[Example 1] In the plating apparatus shown in FIG. 1, the masking member 1 was made of acrylic resin, the soft member 5 of the holding plate 7 was made of silicone rubber, and the hard member 6 was made of acrylic resin, and the electrodes ( A voltage was applied between the anode (anode) 11 and the material to be plated (cathode) 3 to perform silver plating.

この時の圧力箱第１室８内を約０．２Ｋｇｆ／ｃｍ２に
、第２室９内を相対差圧で約−０，５Ｋｇｆ／ｃｏ＋２
にそれぞれ保ち、これにより平行流通路１２のめっき面
近傍を相対差圧で約−〇、１５Ｋｇｆ／ｃｍ２とした。At this time, the pressure inside the first chamber 8 of the pressure box is approximately 0.2Kgf/cm2, and the inside of the second chamber 9 is at a relative differential pressure of approximately -0.5Kgf/co+2.
As a result, the relative pressure in the vicinity of the plating surface of the parallel flow path 12 was maintained at approximately -0, 15 Kgf/cm2.

このめっき液の負圧力により被めっき材３はマスキング
部材ｌおよび押さえ板７の軟質部材５に密着されるとと
もに、外気（大気圧）との圧力差によりめっき液のにじ
み出しが防止され、境界の鮮明なめっき形状を得た。Due to the negative pressure of this plating solution, the material to be plated 3 is brought into close contact with the masking member 1 and the soft member 5 of the holding plate 7, and the pressure difference with the outside air (atmospheric pressure) prevents the plating solution from seeping out. A clear plating shape was obtained.

また、平行流通路１２の長さ２を約４ｍｍ、流通路高さ
ｄを約２ｎｏｓとした。この時得られためフき液の流速
は約１０ｍ／ｓであり、適正なめっきが行える最大電流
密度は約２００Ａ／ｄｒｒ＋’であった。さらに流速を
あげ、最大電流密度を向上することが可能である。Further, the length 2 of the parallel flow passage 12 was approximately 4 mm, and the flow passage height d was approximately 2 nos. The flow rate of the wiping solution obtained at this time was about 10 m/s, and the maximum current density that allowed proper plating was about 200 A/drr+'. It is possible to further increase the flow rate and improve the maximum current density.

［実施例２］ 第２図のめっき装置を用い、被めっき材３をＩＣリード
フレームとしてめっきを施した。押さえ板７の硬質部材
６は熱膨張率の小さいセラミックで、軟質部材５はシリ
コンゴムで構成し、モールド成型した凸部５ａにてリー
ドフレーム３の打抜部（間隙部）を嵌合固定した。マス
キング部材１はセラミックで形成し、表層部１５は厚さ
約０．２１１ｍのシリコンゴムとした。[Example 2] Using the plating apparatus shown in FIG. 2, plating was performed using the material to be plated 3 as an IC lead frame. The hard member 6 of the holding plate 7 is made of ceramic with a small coefficient of thermal expansion, and the soft member 5 is made of silicone rubber, and the punched part (gap part) of the lead frame 3 is fitted and fixed with the molded convex part 5a. . The masking member 1 was made of ceramic, and the surface layer 15 was made of silicone rubber with a thickness of about 0.211 m.

押さえ板７に形成された連通路２！の一端は、タブ部（
ＩＣ素子搭載部）３ｂに開孔させた。Communication path 2 formed in the holding plate 7! One end of the tab (
A hole was made in the IC element mounting part) 3b.

平行流通路１２の長さ２は約８ｏ＋ｍ、流通路高さｄは
約３ＩＩＩ１１とした。The length 2 of the parallel flow path 12 was approximately 8o+m, and the height d of the flow path was approximately 3III11.

かかる条件下で、めっき液側（液流通路側）圧力と加圧
箱側圧力とを以下のように変えてめっきを行ったところ
、ＩＣリードフレーム３のワイヤボンディング部である
リード部先端３Ｃのめっき形状は下記に示すようになっ
た。Under these conditions, when plating was performed by changing the pressure on the plating solution side (liquid flow path side) and the pressure on the pressure box side as shown below, the plating of the lead part tip 3C, which is the wire bonding part of the IC lead frame 3, was The shape is now shown below.

すなわち、めっき液側が相対差圧で−０，２Ｋｇｆ／ｃ
ｍ２程度の負圧とし、外圧（加圧箱圧力）を加えない場
合、第６図のように、リード部先端３Ｃ側面へ若干のめ
っきにじみが見られたが、マスク開孔の外側部すなわち
アクタリード３ｄ側へのにじみ出しはなく、第７図に示
す従来のゴムマスクとノズルを用いためっき法による場
合と比較すると、大幅な改善がみられ、マイグレーショ
ン防止等の機能上の問題点に対しては十分に満足される
ものである。In other words, the relative pressure difference on the plating solution side is -0.2Kgf/c.
When the negative pressure was about m2 and no external pressure (pressure box pressure) was applied, some plating bleeding was observed on the side surface of the lead tip 3C, as shown in Figure 6, but the outside of the mask opening, that is, the Acta Lead There is no oozing to the 3D side, and compared to the conventional plating method using a rubber mask and nozzle as shown in Figure 7, a significant improvement is seen, and functional problems such as migration prevention are solved. It is completely satisfying.

まためっき液側を相対差圧で−０，２Ｋｇｆ／ｃｏ＋２
の負圧とし、加圧箱１６に約０．５Ｋｇｆ／ｃｍ２の空
気を導入した場合は、第３図に示すごとくリード部先端
３ｃ側面あるいはアウタリード３ｄ側等へ全くにじみ出
しのないクリアーなめっき形状が得られた。Also, the relative pressure difference on the plating solution side is -0.2Kgf/co+2
When the negative pressure is set to 0.5 Kgf/cm2 and air is introduced into the pressurized box 16, a clear plating shape with no oozing on the side of the lead tip 3c or the outer lead 3d side as shown in Fig. 3 is obtained. was gotten.

開孔４の形状、大きさを選ぶことにより、第４図、第５
図のようなめっき形状を得ることができる。By selecting the shape and size of the opening 4,
The plating shape shown in the figure can be obtained.

〈発明の効果〉 以上詳述したように本発明によれば、ＩＣリードフレー
ムのリード先端等、微小部分めっきが要求されるものに
対し、微細でかつめっきにじみのないクリアでかつ高速
なめっきを行うことができる。<Effects of the Invention> As described in detail above, according to the present invention, it is possible to perform fine, clear and high-speed plating without plating bleeding on items that require minute plating, such as the lead tips of IC lead frames. It can be carried out.

これにより、従来、銀めっきのマイグレーション対策と
して、めっき後打抜成型を行ったり、あるいは銀の替わ
りに金めつきを行うなど、より手数のかかる、あるいは
より高価な方法で行っていためっき方法およびその装置
を銀の微小めフきに代替することができ、その経済的、
節資源的効果は大きい。As a result, conventional plating methods that were more labor-intensive or more expensive, such as punching and molding after plating or plating with gold instead of silver, were used to prevent migration of silver plating. The device can be replaced with a silver micromesh cloth, which is economical and
The effect of saving resources is significant.

またマイグレーションによる短絡事故を防止できること
により、めっき物およびこのめっき物を用いたＩＣ，Ｌ
ＳＩ等の信頼性を著しく向上させることができ、工業的
面のみならず社会的面においてもその波及効果は大きい
。In addition, by being able to prevent short-circuit accidents due to migration, it is possible to prevent short-circuit accidents due to migration.
The reliability of SI etc. can be significantly improved, and the ripple effect is large not only in the industrial aspect but also in the social aspect.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は、本発明の一実施例を示すめっき装置の断面図
である。 第２図は、本発明の他の実施例を示すめっき装置の断面
図である。 第３図、第４図、第５図は、本発明により得られるＩＣ
リードフレームの微小部分めっきの状態を示す外観図で
ある。 第６図は、本発明において、めっき液態に負圧を与えな
い場合の微小部分のめっき状態を示す外観図である。 第７図は、従来例における微小部分のめっき状態を示す
外観図である。 ７？ＪＢ　ａ図および′ｆＳＢｂ図は、従来のめっき装
置の断面図である。 符号の説明 ｌ・−マスキング部材、２・・・圧力箱、３・・・被め
っき材、　　４・−開孔、５・・・押さえ板の軟質部材
、 ６・・・押さえ板の硬質部材、 ７・・・押さえ板（押圧部材）、 ８・・・圧力箱第１室、　９・・・圧力箱第２室、１０
・・・めっき液流通路、 １１−・・電極（陽極）、１２−・・平行流通路、１３
−・・台座部、　　　　１４・・・エアシリンダ、１５
−・・マスキング部材表層部、 １６−−・加圧箱（気体加圧手段）、 ２０・・・リードピン、　　２１−・連通路、２２・・
・０リング ＦＩＧ、１ ＦＩＧ、３　　　　　　　　　　　ＦＩＧ、４ＦＩＧ、
５　　　　　　　　　ＦＩＧ、６Ｆ　Ｉ　Ｇ、　７ ＣFIG. 1 is a sectional view of a plating apparatus showing an embodiment of the present invention. FIG. 2 is a sectional view of a plating apparatus showing another embodiment of the present invention. FIGS. 3, 4, and 5 show ICs obtained according to the present invention.
FIG. 3 is an external view showing the state of minute partial plating on the lead frame. FIG. 6 is an external view showing the plating state of a minute portion when no negative pressure is applied to the plating liquid state in the present invention. FIG. 7 is an external view showing the plating state of a minute portion in a conventional example. 7? Figure JBa and Figure 'fSBb are cross-sectional views of conventional plating equipment. Explanation of symbols 1--Masking member, 2--Pressure box, 3--Plated material, 4--Open hole, 5--Soft member of holding plate, 6--Hard member of holding plate, 7... Pressing plate (pressing member), 8... Pressure box first chamber, 9... Pressure box second chamber, 10
... Plating solution flow path, 11-... Electrode (anode), 12-... Parallel flow path, 13
-...Pedestal part, 14...Air cylinder, 15
---Masking member surface layer, 16---Pressure box (gas pressurizing means), 20--Lead pin, 21--Communication path, 22--
・0 ring FIG, 1 FIG, 3 FIG, 4 FIG,
5 FIG, 6FI G, 7 C

Claims (5)

【特許請求の範囲】[Claims] （１）被めっき材に、めっき面形状を決定する開孔と、
該開孔に連通しかつ前記めっき面に平行に形成された平
行流通路とを有するマスキング部材を押し当て、該平行
流通路内に供給されためっき液にて前記開孔を介して部
分めっきを行うに際し、前記被めっき材の非めっき面に
かかる外圧に対し、前記平行流通路の開孔近傍のめっき
液により前記被めっき材のめっき面にかかる内圧を０．
１５Ｋｇｆ／ｃｍ＾２以上低圧にすることを特徴とする
部分めっき法。(1) An opening in the material to be plated that determines the shape of the plated surface,
A masking member having a parallel flow passage communicating with the opening and formed parallel to the plating surface is pressed against the masking member, and partial plating is performed through the opening with the plating solution supplied into the parallel flow passage. When performing this, the internal pressure applied to the plating surface of the plating material by the plating solution near the opening of the parallel flow path is reduced to 0.
A partial plating method characterized by applying a low pressure of 15Kgf/cm^2 or more. （２）被めっき材のめっき面形状を決定する開孔と該開
孔に連通しかつ前記めっき面に平行に形成された平行流
通路とを有するマスキング部材と、めっき液を前記平行
流通路内に送り込むめっき液駆動手段と、前記被めっき
材を前記マスキング部材に対して押圧する押圧手段とを
有し、前記めっき液駆動手段により、被めっき材の非め
っき面にかかる外圧に対し、前記平行流通路の開孔近傍
のめっき液により前記被めっき材のめっき面にかかる内
圧が０．１５Ｋｇｆ／ｃｍ＾２以上低圧に保たれるよう
構成してなることを特徴とする部分めっき装置。(2) A masking member having an aperture that determines the shape of the plating surface of the material to be plated, and a parallel flow path communicating with the aperture and formed parallel to the plating surface, and directing the plating solution into the parallel flow path. and a pressing means for pressing the material to be plated against the masking member. A partial plating apparatus characterized in that the internal pressure applied to the plating surface of the material to be plated is maintained at a low pressure of 0.15 Kgf/cm^2 or more by the plating solution near the opening of the flow path. （３）被めっき材のめっき面形状を決定する開孔と該開
孔に連通しかつ前記めっき面に平行に形成された平行流
通路とを有するマスキング部材と、めっき液を前記平行
流通路内に送り込むめっき液駆動手段と、前記被めっき
材を前記マスキング部材に対して押圧する押圧手段と、
前記被めっき材の非めっき面を加圧する気体加圧手段と
を有し、前記めっき液駆動手段および気体加圧手段によ
り、被めっき材にかかる外圧に対し、前記平行流通路の
開孔近傍のめっき液により前記被めっき材のめっき面に
かかる内圧が０．１５Ｋｇｆ／ｃｍ＾２以上低圧に保た
れるよう構成してなることを特徴とする部分めっき装置
。(3) A masking member having an aperture that determines the shape of the plating surface of the material to be plated, and a parallel flow path communicating with the aperture and formed parallel to the plating surface, and a masking member for directing the plating solution into the parallel flow path. a plating solution driving means for feeding the plating solution into the plating solution, and a pressing means for pressing the material to be plated against the masking member;
a gas pressurizing means for pressurizing the non-plated surface of the material to be plated, and the plating solution driving means and the gas pressurizing means control the external pressure applied to the material to be plated in the vicinity of the opening of the parallel flow path. A partial plating apparatus characterized in that the internal pressure applied to the plating surface of the material to be plated is maintained at a low pressure of 0.15 Kgf/cm^2 or more by the plating solution. （４）前記めっき液駆動手段は、駆動ポンプおよびまた
はアスピレータである特許請求の範囲第２項もしくは第
３項に記載の部分めっき装置。(4) The partial plating apparatus according to claim 2 or 3, wherein the plating solution driving means is a driving pump and/or an aspirator. （５）前記平行流通路の長さをｌ、流通路高さをｄ、該
平行流通路のめっき液流速をｖとするとき、ｖ≧１０ｍ
／ｓにおいてｌ／ｄ≦４で、ｖ＜１０ｍ／ｓにおいてｌ
／ｄ≦１５を満足する特許請求の範囲第２、３もしくは
第４項に記載の部分めっき装置。(5) When the length of the parallel flow path is l, the height of the flow path is d, and the flow rate of the plating solution in the parallel flow path is v, then v≧10 m
/s with l/d≦4 and v<10m/s with l/d≦4
The partial plating apparatus according to claim 2, 3 or 4, which satisfies /d≦15.