JP3796857B2 - Surface treatment method and apparatus - Google Patents

Description

このように、添加物として水を加えると、プラズマ発生部６０内部でのオゾンの発生を抑制でき、これによりリードフレーム１２の酸化を防止することが可能となる。
【００８４】
なお、この水の添加に関しては、図１，２に示す熱分解、光分解の場合にも、上述の放電による分解と同様に有効である。
【００８５】
プラズマ発生部を持たない表面処理ユニット
次に、図５の方式による表面処理装置及びその方法について、図１１を参照して説明する。
【００８６】
図１１は、装置全体の構成を示すもので、図６の場合と同様に、給気連結管２０及び排気連結管２４が接続された表面処理ユニット１１０が設けられている。この表面処理ユニット１１０は、１つの筺体１１２の内部に、キャリアガス給気管１２０，液体収容部１３０，排気管１４０及び除害装置１５０を有している。
【００８７】
キャリアガス給気管１２０として、液体収容部１３０の上流側の第１のキャリアガス給気管１２０ａと、液体収容部１３０の下流側の第２のキャリアガス給気管１２０ｂと、第１，第２のキャリアガス給気管同士を連結する第３のキャリアガス給気管１２０ｃを有している。
【００８８】
液体収容部１３０の内部には、ＨＦ、ＨＣｌなどのハロゲン化水素の水溶液が収容されている。第１のキャリアガス給気管１２０ａを介して液体収容部１３０内部に導入された例えばＮ₂などのキャリアガスは、その液体と接触することで、酸性に富んだ処理ガスとされる。この処理ガスは、第２のキャリアガス給気管１２０ｂを介して液体収容部１３０から排出されると共に、第３のキャリアガス給気管１２０ｃからのキャリアガス自体の圧力により圧送され、表面処理ユニット１１０の外部に導出されることになる。
【００８９】
この酸性に富んだ処理ガスは、図１０に示す給気連結管２０，給気部２２を介して、ＩＣ１０のリードフレーム１２に曝露されることになる。これにより、リードフレーム１２の表面は、下記の化学反応により表面処理されることになる。
【００９０】
処理ガスとしてフッ化水素ＨＦを用いた場合には、下記の化学式に従い表面処理がなされる。
【００９１】
ＳｎＯ＋２ＨＦ→ＳｎＦ₂＋Ｈ₂Ｏ
処理ガスとして、塩化水素Ｈｃｌを用いた場合には、下記の化学式に従い表面処理が成される。
【００９２】
ＳｎＯ＋２ＨＣｌ→ＳｎＣｌ₂＋Ｈ₂Ｏ
なお、本発明の範囲外ではあるが、液体収容部１３０の内部にＨ₂ＮＯ₃などの酸性液体、あるいはアンモニア水などの塩基性液体を収容することもできる。硝酸Ｈ₂ＮＯ₃を用いた場合には、下記の化学式により表面処理がなされる。
【００９３】
ＳｎＯ＋Ｈ₂ＮＯ₃→ＳｎＮＯ₃＋Ｈ₂Ｏ
この他、液体収容部１３０にシュウ酸などの他の酸性気体を収納することもできる。
【００９４】
液体収容部１３２塩基性液体例えばアンモニア水を収容した場合には、下記の化学式に従い表面処理がなされる。
【００９５】
ＳｎＯ＋ＮＨ₃＋２Ｈ₂Ｏ→ＮＨ⁴⁺［Ｓｎ（ＯＨ）₃］^-
一方、リードフレーム１２に曝露された処理ガスは、排気連結管２４を介して表面処理ユニット１１０内部に導入されることになる。ここで、上述の酸性又は塩基性に富んだ処理ガスは、それ自体が腐食性ガスであり、これを大気中に放出することはできない。そこで、この表面処理ユニット１１０内部では、排気管１４０を介して除害装置１５０に処理ガスを導き、この除外装置１５０にて処理ガス中の上記の腐蝕成分を除外することになる。
【００９６】
なお、図１１に示す表面処理ユニット１１０の場合も、図９に示す場合と同様に、工場内の給排気設備を用いない構成、すなわち、給気ファン、排気ファン及びそれらを駆動するファン駆動装置を筺体１１２内部に増設することもできる。
【００９７】
表面処理ユニットの各種タイプについて
次に、上述した表面処理ユニット３０，１００及び１１０の形状もしくはそれらに連結される給気連結管２０、排気連結管２４の形状を変更した各種タイプについて、図１２以降を参照して説明する。
【００９８】
（１）ラインタイプ
図１２及び図１３に示すラインタイプの表面処理ユニット１６０は、コンベアライン１４により搬送される例えば板状のワーク５００と対向する上方位置に、設けられている。この表面処理ユニット１６０は、筺体１６１の下部に給排気部１６２を備えている。この給排気部１６２は、給気管１６４及び排気管１６６にて二重管構造を構成している。本実施例では、中心部に給気管１６４を配置し、その周囲に排気管１６６を配置し、排気管１６６の下端部は、傘状に広がる形状となっている。
【００９９】
コンベアライン１４によりワーク５００が間欠的にあるいは連続的に搬送されると、このワーク５００が表面処理ユニットの給排気部１６２と対向することで、ワーク５００の表面が表面処理されることになる。これにより、表面処理ユニット１６０を固定しながらも、ワーク５００の全面について、多数のワーク５００を連続的に表面処理することが可能となる。
【０１００】
（２）スタンドタイプ
図１４に示すスタンドタイプの表面処理ユニット２００は、載置可能な底面を有する筺体２０１を有している。この筺体２０１内部には、上述した通り原料ガス、及び／又はキャリアガスが導入され、除害装置を経由して排気ガスが排気される。この筺体２０１には、上方に伸びる給気連結管２１０及び排気連結管２３０が設けられている。給気連結管２１０は屈曲され、下端にて開口する給気部２２０を有する。この給気部２２０の周囲には、処理ガスの拡散を防止するための傘状の拡散防止板２２２が設けられている。一方、排気連結管２３０は、拡散防止板２２２と対向する位置に、上方に向かうに従い開口面積の増大する傘状の排気吸引部２４０が形成されている。
【０１０１】
そして、図１４及び図１５に示すとおり、ワークとして例えば端部の被覆材がはがされた線材２５０の先端部を表面する処理に際して、この線材２５０の予めメッキ処理された先端部２５２を給気部２２０の直下の位置に配置する。こうすると、給気部２２０より導出される処理ガスにより線材２５０の先端部２５２が表面処理され、その曝露された処理ガスは排気吸引部２４０及び排気連結管２３０を介して筺体２０１内の除害装置に導かれることになる。
【０１０２】
このように、スタンドタイプの表面処理ユニット２００を用いることで、空気中に局所的な処理ガスの雰囲気を作ることができ、線材２５０などのワークを容易に表面処理することが可能となる。
【０１０３】
（３）棒状タイプについて
図１６及び図１７に示す実施例は、表面処理ユニット３００自体を、例えば半田ごてのような筒状の筺体３０１にて構成したものである。この筺体３０１に連結された給気連結管３１０及び排気連結管３２０は二重管構造となっており、内側の給気連結管３１０により処理ガスがワーク５００に向けて導出され、外側の排気連結管３２０よりその曝露された処理ガスが筺体３０１内部に導かれる。排気連結管３２０の先端部は、排気領域を拡大する観点から、図１６及び図１７に示すとおり、傘状に広がる形状とすることが好ましい。
【０１０４】
このように、表面処理ユニット３００自体を棒状タイプに構成すれば、この表面処理ユニット３００自体を手で操作して、各種ワークの表面処理を行うことが可能となる。
【０１０５】
（４）トースタータイプ
図１８及び図１９に示す表面処理ユニット４００は、筺体４０１の一面例えばその上面に、板状のワーク５００を挿入できるスリット状の挿入部４１０を有している。このスリット状の挿入部４１０には排気管４２０が連結されている。一方、スリット状の挿入部４１０の例えば両側壁には、該側壁にて一端が開口する処理ガス給気管４３０、キャリアガス給気管４４０がそれぞれ設けられている。
【０１０６】
この構成によれば、板状のワーク５００を、筺体４０１の上面に設けられたスリット状の挿入部４１０内部に挿入することで、このワーク５００の両面より処理ガスが吹き付けられ、板状のワーク５００の両面を同時に表面処理することが可能となる。なお、ワーク５００の片面のみが表面処理されるものにあっては、処理ガス給気管４３０をスリット状の挿入部４１０の一方の側壁のみに開口させればよい。
【０１０７】
（５）バッチ処理タイプ
図２０は、多数のワークをバッチ式で処理する装置を示している。この装置は、上述の表面処理ユニット３０（又は１００又は１１０）に接続された給気連結管２０及び排気連結管２４を、バッチ処理ボックス４５０に連結している。このバッチ処理ボックス４５０は、内部に多数のワーク５１０を収容するものである。バッチ処理されるワーク５１０としては、上述のＩＣ１０、線材２５０、板状のワーク５００の他、例えばロール状に巻回されたＴＡＢテープであってもよい。
【０１０８】
このバッチ処理タイプによれば、一度に多数のワーク５１０を表面処理することが可能となる。なお、本発明の処理方法に表面処理されたワークは、改善されたその半田の濡れ性を、表面処理後比較的長い時間維持することができるため、バッチ処理後半田付けまでワークをストックしておいても、良好な半田付けを行うことができる。
【０１０９】
【実施例】
次に、本発明方法により表面処理されたワークの半田の濡れ性を評価するための実験結果について、表２，表３を参照して説明する。
【０１１０】
水晶発振子の電極に銀を蒸着した日から１３日後に、該水晶発振子の電極に半田付けされる線材の先端を各種条件下にて表面処理し、同日に半田付け（マウント）した時の、半田の流れ評価を下記の表２に示す。
【０１１１】
【表２】

ここで、条件１は表面処理の無い場合であり、条件２〜６及び８はいずれも原料ガスにＣＦ₄（５０ｃｃ／ｍｉｎ）、キャリアガスにＮ₂（２０リットル／ｍｉｎ）を用い、ＣＦ₄は純水を通過させて水分を添加した。条件７は、原料ガスは条件２などと同じとし、キャリアガスに圧縮空気（２０リットル／ｍｉｎ）を用いた。プラズマ生成条件として、条件２ではパワーを５０〜９０Ｗと比較的低パワーとし、条件３〜８では２５０Ｗとした。
【０１１２】
上記の表２にて時間は９ｃｍの長さをスキャンしたトータル時間を示している。また、マウント条件は、半田付け時の半田ごての本電圧及び予備電圧を示している。
【０１１３】
表２に示すとおり、表面処理をしていない条件１と比較すると、条件２〜８でいずれも半田の流れ結果は向上しており、特にキャリアガスにＮ₂を用いた条件２〜６及び８ではきわめて良好な結果が得られた。
【０１１４】
表２中の条件３での表面処理を行ったものと、表面処理をしていないもとについて、それぞれマウント数量を増やして半田の流れ不良及びマウント後の水晶発振子の電気的特性とを評価した結果を、下記の表３に示す。
【０１１５】
【表３】

表３中の周波数ｆ₀は水晶発振子の発振周波数を示し、条件１，３が処理無しのもの、条件２，４が表面処理有りのものをそれぞれ示す。なお、条件１，２では、水晶発振子の電極に銀を蒸着した日から１４日後に、該水晶発振子の電極に線材を半田付け（マウント）した。条件２の表面処理工程は、マウント工程の２日前に実施した。条件３，４では、水晶発振子の電極に銀を蒸着した日から１７日後に、該水晶発振子の電極に線材を半田付け（マウント）した。条件４の表面処理工程は、マウント工程の２日前に実施した。
【０１１６】
条件１と２との比較、条件３と４との比較から明らかなように、表面処理を実施した方が、半田流れ不良率及び電気特性不良率が共にほぼ半減していることが分かる。
【０１１７】
＜比較例１＞
図３の方式は、ハロゲン化合物が一対の電極間での放電により分解されたハロゲン又はハロゲン化水素を処理ガスとして用いるものであり、被処理体は直接プラズマに晒されない間接放電処理である。一方、一対の電極の一方に被処理体を載置し、被処理体をプラズマに直接晒して処理する直接放電処理は公知である。
【０１１８】
下記の表４は、本実施例の間接放電処理を、公知の直接放電処理と、いずれの処理も行われない未処理のものとに対して、半田の濡れ性の良否を比較したものである。なお、本実施例の間接放電処理では、原料ガスＣＦ₄を５００ｃｃ／ｍｉｎ、キャリアガスＮ₂を２０リットル／ｍｉｎで供給した。直接放電処理では、原料ガスＣＦ₄を５００ｃｃ／ｍｉｎ、プラズマ生成用ガスＨｅを２０リットル／ｍｉｎで供給した。
【０１１９】
【表４】

表４から明らかなように、本実施例の間接放電処理では不良率が格段に低下していることが分かる。ここで、間接放電処理での不良原因は、全て半田の流れ過ぎによるもので、半田の濡れ性が向上していることでは良品と変わりはない。
【０１２０】
これに対して、上記の実験結果によると、直接放電処理では、半田流れが不良となる不良率が、未処理の場合よりも２０％低下しただけであった。この理由は下記の通りと考えられる。その一つは、被処理体のリード先端部分に強い放電が生じ、部分的にしか処理されないことである。他の一つは、電極間ギャップが数ｍｍと狭い直接放電処理では、被処理体のセット状態のばらつきにより、プラズマの状態が変化するからである。プラズマ強度が大きすぎると、被処理体が変色し、半田の流れは不良となる。
【０１２１】
＜比較例２＞
上述した各実施例では、処理ガスとしてハロゲン又はハロゲン化水素を含む処理ガスを用いているが、プラズマ発生部にて発生した例えばフッ素ラジカル等の活性種を、プラズマ発生部外に配置した被処理体に導いて処理する方式も知られている。ただし、活性種はその寿命があるため、本実施例の間接放電処理と比較すると、プラズマ発生部から被処理体までの距離を大きくすることはできない。
【０１２２】
プラズマ発生部に連結される処理ガス供給管として、一般に配管チューブとして知られている１／４径サイズ（外径６．３５ｍｍ、内径３．１７ｍｍ）を使用した場合、原料ガス供給流量とチューブ断面積とから、処理ガスの流速を求めてみた。原料ガスの供給流量を１００ｃｃ／ｍｉｎとした場合、処理ガスの流速は２１．１２ｃｍ／ｓとなる。フッ素ラジカルの寿命は、１／１０００ｓ以下であるので、プラズマ発生部から０．０２１１ｃｍ離れた位置で消滅する。原料ガスの供給流量を３０ｃｃ／ｍｉｎとした場合には、処理ガスの流速は６．３３５ｃｍ／ｓとなり、プラズマ発生部から０．００６３ｃｍ離れた位置で消滅する。
【０１２３】
これに対して、上述した各実施例では、処理ガスとしてハロゲン又はハロゲン化水素を含む処理ガスを用いているので、処理ガス生成用容器より十分に離れた位置に被処理体をおいても処理が可能である。
【０１２４】
【図面の簡単な説明】
【図１】熱分解により処理ガスを生成する装置を模式的に示す本発明の実施例の概略説明図である。
【図２】光分解により処理ガスを生成する装置を模式的に示す本発明の実施例の概略説明図である。
【図３】放電による分解により処理ガスを生成する装置を模式的に示す本発明の実施例の概略説明図である。
【図４】電気分解により処理ガスを生成する装置を模式的に示す本発明の実施例の概略説明図である。
【図５】液体との接触により処理ガスを生成する装置を模式的に示す本発明の実施例の概略説明図である。
【図６】本発明の実施例に係る表面処理装置の全体構成を示す概略説明図である。
【図７】図６に示す表面処理ユニットの内部構成を示す概略説明図である。
【図８】図７示すプラズマ発生部の構成を示す概略説明図である。
【図９】表面処理ユニットの他の実施例を示す概略説明図である。
【図１０】処理ガスを直接にワークに向けて導出する実施例を示す概略説明図である。
【図１１】表面処理ユニットのさらに他の実施例を示す概略説明図である。
【図１２】表面処理ユニツトによりラインタイプの処理装置を構成した実施例を示す概略説明図である。
【図１３】図１２に示す表面処理ユニットの給排気部を示す概略断面図である。
【図１４】表面処理ユニツトによりスタンドタイプの処理装置を構成した実施例を示す概略説明図である。
【図１５】図１４に示す表面処理ユニットの給排気部を示す概略断面図である。
【図１６】表面処理ユニツトにより棒状タイプの処理装置を構成した実施例を示す概略説明図である。
【図１７】図１６に示す表面処理ユニットの給排気部を示す概略断面図である。
【図１８】表面処理ユニツトによりトースタータイプの処理装置を構成した実施例を示す概略説明図である。
【図１９】図１８に示す表面処理ユニットの給排気部を示す概略断面図である。
【図２０】表面処理ユニツトによりバッチ処理タイプの処理装置を構成した実施例を示す概略説明図である。
【符号の説明】
１ 処理ガス生成用容器
２ 処理ガス供給管
３ 原料ガス供給管
４ 加熱器
５ ＵＶランプ
６ プラズマ発生部
７ 仕切板
８ａ，８ｂ 電極
９ キャリアガス供給管
１０、２５０、５００、 ワーク
２０、２１０、３１０ 給気連結管
２４、２３０、３２０ 排気連結管
３０、１００、１１０、１６０、２００、３００、４００ 表面処理ユニット
３２、１１２、１６１、２０１、３０１、４０１ 筺体
４０、１６４、４３０ 処理ガス給気管
４２、９２ 流量計
４４ ガスボンベ
５０ 電源
６０ プラズマ発生部
６２ａ、６２ｂ 電極
７０、１４０、１６６、４２０ 排気管
８０、１５０ 除害装置
８２ 排気ファン
９０、１２０ キャリアガス給気管
９４ 給気ファン
１３０ 液体収容部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surface treatment method and apparatus for surface-treating a workpiece such as a semiconductor device, a crystal oscillator, a circuit board, or a wire to improve solder wettability, for example.
[0002]
[Background Art and Problems to be Solved by the Invention]
Conventionally, metal surfaces are cleaned by hydrogen atoms generated by vacuum plasma.DoA method (Japanese Patent Laid-Open No. 2-190489) and a method for improving the wettability of solder on a substrate by vacuum plasma cleaning (Japanese Patent Laid-Open No. 3-174972) have been proposed.
[0003]
The present applicant has already proposed a technique for activating gas by atmospheric pressure plasma instead of the conventional vacuum plasma and improving the wettability of the work to be soldered by active species such as ions and excited species. (WO94 / 22628, Japanese Patent Application No. 7-2950).
[0004]
Here, in the treatment using the vacuum plasma and the atmospheric pressure plasma described above, the surface treatment is performed by the active species excited by the plasma.
[0005]
Here, the direct discharge treatment method in which the object to be treated is exposed to plasma is not preferable because the physical properties of the object to be treated are easily destroyed due to plasma damage. In particular, if the surface to be processed of the object to be processed is metal, strong plasma is generated intensively on the protruding portion, and the entire surface to be processed cannot be processed uniformly.
[0006]
On the other hand, an indirect discharge treatment method has been proposed in which active species generated in a plasma generation unit are guided to a target object disposed at a position where it is not exposed to plasma. In this case, the plasma damage described above does not occur.
[0007]
However, this active species has a lifetime, and since this lifetime is relatively short, the surface treatment becomes impossible or the processing efficiency is greatly reduced by placing the object to be processed at a position away from the plasma generating portion. Resulting in. Therefore, this indirect discharge treatment method is not practical due to restrictions on the installation location of the object to be treated.
[0008]
Accordingly, an object of the present invention is to provide a surface treatment method and apparatus capable of modifying the surface of the object to be treated without causing plasma damage and having a high degree of freedom in the installation location of the object to be treated. There is to do.
[0009]
Another object of the present invention is to provide a surface treatment method and apparatus capable of producing a highly reactive treatment gas from a stable substance and modifying the surface of the object to be treated with the treatment gas. is there.
[0010]
Still another object of the present invention is to provide a surface treatment that does not necessarily require a relatively expensive helium He and that improves the surface of the object to be processed at a low running cost while reducing the consumption of the processing gas. It is an object of the present invention to provide a surface treatment apparatus and a method thereof.
[0011]
Still another object of the present invention is to provide a surface treatment apparatus and method capable of performing a surface treatment for modifying the surface of an object to be treated while suppressing generation of ozone that oxidizes the object to be treated.
[0012]
[Means for Solving the Problem and Action]
The method of the present invention is characterized in that a treatment gas containing halogen or hydrogen halide is brought into contact with the surface of the object to be treated, and the surface of the object to be treated is treated. As a representative of halogen and hydrogen halide, fluorine F₂And hydrogen fluoride HF.
[0013]
In the present invention, an object to be treated can be surface-treated by a chemical reaction with a treatment gas containing a highly reactive halogen or hydrogen halide without depending on an active species having a short lifetime such as a fluorine radical. Moreover, since the object to be processed is not exposed to plasma, defects due to plasma damage do not occur in the object to be processed.
[0014]
Method of the present inventionsoIt is preferable to decompose the halogen compound by one or a combination of thermal decomposition, photodecomposition, decomposition by discharge, or electrolysis to generate the processing gas. For this purpose, in the apparatus of the present invention, a processing gas generating means for generating a processing gas by decomposing a halogen compound by any one of the above methods, and a processing gas supply means for guiding the processing gas to the surface of the object to be processed Is provided.
[0015]
Halogen or hydrogen halide itself is highly reactive and highly corrosive, so a stable halogen compound is used as a raw material, which is decomposed by any of the above methods to generate a processing gas. Since the lifetime of this halogen or hydrogen halide is not short as in the case of active species, there is no restriction on the time to reach the target object after decomposition. Accordingly, the degree of freedom in setting the processing position of the object to be processed is increased.
[0016]
Here, when an organic halogen compound is used as a halogen compound as a raw material, these are neutral and easy to handle.
[0017]
In addition, as a halogen compound suitable for thermal decomposition, photodecomposition and decomposition by discharge, NF_Three, SF₆, CF_FourOr NH_FourIt is preferable to use any one of F. These halogen compounds become raw material gases and are supplied to the processing gas generating means via the raw material gas supplying means.
[0018]
When the halogen compound is decomposed by discharge, the source gas may be excited and decomposed by a pair of electrodes to which a low frequency AC voltage or DC voltage of 50 kHz or less is applied at atmospheric pressure or a pressure in the vicinity thereof. preferable. For this purpose, the processing gas generating means of the apparatus of the present invention comprises a power source that outputs an AC voltage or a DC voltage with a low frequency of 50 kHz or less, and a pair of electrodes to which the voltage is applied, and the atmospheric pressure or a pressure in the vicinity thereof. And a plasma generation part for inducing plasma below.
[0019]
When the above-mentioned low frequency AC voltage or DC voltage is applied between a pair of electrodes, the peak-to-peak voltage of the discharge voltage can be made relatively large and stable even without supplying He or the like as a plasma generating gas. A discharge can be generated. In order to generate such stable atmospheric pressure plasma, it is not always necessary to use He, and the running cost can be reduced.
[0020]
It is preferable to carry out the decomposition process of the halogen compound by the thermal decomposition, photodecomposition and discharge in an atmosphere containing moisture. This is because hydrogen halide can be efficiently decomposed from the halogen compound due to the presence of moisture.
[0021]
As a halogen compound suitable for electrolysis, an aqueous solution of a halide salt that is easily electrolyzed is suitable.
[0022]
In any case of thermal decomposition, photodecomposition, decomposition by electric discharge, or electrolysis, it is preferable that the processing gas is pumped by a carrier gas and brought into contact with the object to be processed. At this time, it is better to mix a carrier gas with the processing gas after the halogen compound decomposition step. This is because even when a gas containing oxygen is used as the carrier gas, the generation of ozone does not increase when the halogen compound is decomposed. For this reason, in the apparatus of the present invention, the carrier gas supply means is connected to either the raw material gas supply means or the processing gas supply means.
[0023]
In the method of the present invention and the device of the present invention, instead of the above decomposition method, a processing gas can be generated by bringing a carrier gas into contact with an aqueous solution of halogen or hydrogen halide.
[0024]
In this way, a processing gas containing a halogen or hydrogen halide liquid is generated, whereby the object to be processed can be processed.
[0025]
In the method of the present invention,
Forcibly exhausting the processing gas and the reaction product supplied toward the object to be processed;
Trapping process gas or the reaction product in the middle of exhaust,
It is preferable to further have. For this purpose, the apparatus according to the present invention includes forced exhaust means and trap means.
[0026]
Since the processing gas is highly corrosive, it can be recovered without being scattered into the atmosphere by trapping an unreacted highly corrosive processing gas or reaction product during forced exhaust.
[0027]
In the method of the present invention, the treatment gas is brought into contact with the surface of the object to be processed, whereby the oxide on the surface of the object to be processed is replaced with a halogen compound, and the process is applied to a process for improving the wettability of the solder on the surface. It is preferable.
[0028]
As an object to be processed suitable for this type of processing, a circuit board, an electronic component such as an integrated circuit (IC), a wire to be soldered, or a crystal resonator can be given.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the surface treatment method and the surface treatment apparatus of the present invention will be specifically described with reference to the drawings.
[0030]
<Process gas generation method>
In the present invention, halogen such as F₂, Cl₂, Br₂, I₂Or a treatment gas containing a hydrogen halide such as HF, HCl, HBr, HI or the like, and the object to be treated is surface-treated with this highly reactive treatment gas. In order to generate this highly reactive processing gas, any one of the five methods shown in FIGS.
[0031]
1 to 5, as a common configuration, a processing gas generation container 1 and a processing gas supply pipe 2 that guides the generated processing gas toward an object to be processed are included.
[0032]
In FIG. 1, a halogen compound that is a source gas, such as NF_ThreeIs supplied to the processing gas generation container 1 and a heater 4 for heating the inside of the processing gas generation container 1. In FIG. 1, in the processing gas generation container 1, the halogen compound is thermally decomposed by thermal energy to generate a processing gas containing halogen or hydrogen halide.
[0033]
Source gas is NF_ThreeThe temperature required to thermally decompose this is 300 ° C. or higher, and when heated at 500 ° C. in this example,
2NF_Three→ N₂+ 3F₂
Fluorine F₂Was able to be produced.
[0034]
In the embodiment of FIG. 2, in the processing gas generation vessel 1 to which the processing gas supply pipe 2 and the raw material gas supply pipe 3 are connected, a halogen compound as a raw material gas is photodecomposed to generate a processing gas. Yes. For this purpose, a UV lamp 5 for irradiating light, for example, ultraviolet rays, is provided in the processing gas generation container 1.
[0035]
Source gas is NF_ThreeThe lamp output of the UV lamp 5 is 100 mW / cm²When the wavelength of the emitted light is set to 400 nm, photolysis of the same reaction formula as in FIG.₂Was able to be produced.
[0036]
In the embodiment of FIG. 3, in the processing gas generation container 1 to which the processing gas supply pipe 2 and the raw material gas supply pipe 3 are connected, the halogen compound as the raw material gas is applied at atmospheric pressure or a pressure in the vicinity thereof. The gas is decomposed by electric discharge to generate a processing gas. For this purpose, a plasma generator 6 having a pair of electrodes is provided in the processing gas generation container 1.
[0037]
Using the apparatus of FIG. 3, the source gas CF_FourWas supplied at a rate of 100 cc / min, the power supply frequency supplied to the pair of electrodes was about 10 kHz, and a discharge was generated with a peak-to-peak voltage of AC 10 kVpp. At this time, the source gas is
2CF_Four→ C₂F₆+ F₂
And fluorine F₂Was able to be produced.
[0038]
Using the apparatus of FIG. 3, CF as a source gas_Four+ H₂When O was supplied at 300 cc / min and other conditions were set the same as above,
CF_Four+ 2H₂O → CO₂+ 4HF
And a treatment gas containing about 7200 ppm of hydrogen fluoride HF could be generated. Thus, hydrogen fluoride was able to be generated efficiently by adding water.
[0039]
In addition, as described above, by using a power supply frequency of 10 kHz and a low frequency, discharge could be stably generated without supplying He. As a result, the running cost can be reduced. In order to stably cause discharge without supplying He, it is necessary that the peak-to-peak voltage of the discharge voltage be larger than a certain value using a low frequency. According to the experiments by the present inventors, it is possible to confirm the above-mentioned discharge with each DC voltage of DC voltage, 10 kHz, 30 kHz, and 40 kHz, and from the viewpoint of ensuring a large peak-to-peak voltage of the discharge voltage, a low frequency of 50 kHz or less. An alternating voltage or a direct voltage has been found useful.
[0040]
Moreover, as a halogen compound decomposed by the apparatus of FIGS._Four, C_nF_{(2n + 2)}Perfluorocarbons such as C₂F₂H_FourHFC, C, etc.₂F₂Cl_FourCFC, C₂H_ThreeCl_ThreeChlorinated solvents such as C,₂F₂Br_FourWhen organic halogen compounds such as halons are used, they are excellent in terms of handling because they are neutral, unlike for example hydrogen halides..
[0041]
In the embodiment of FIG. 4, a processing gas is generated by electrolyzing an aqueous solution of a halogen compound in a processing gas generation container 1 to which a processing gas supply pipe 2 is connected. For this purpose, a halogenated salt, for example, an aqueous solution of NaF having a concentration of 2% is accommodated in the processing gas generating vessel 1 as an aqueous solution of a halogen compound, and electrodes 8a and 8b are provided in each region partitioned by the partition plate 7. Arranged. For example, when DC 24V is applied to the electrodes 8a and 8b, fluorine F₂Was able to be produced.
[0042]
In addition, examples of the halogenated salt suitable for electrolysis include NaF, KF, LiF, CsF, NaCl, KCl, KBr, NaBr, and NaI.
[0043]
In the embodiment of FIG. 5, the carrier gas is brought into contact with an aqueous solution of halogen or hydrogen halide in the processing gas generation vessel 1 to which the carrier gas supply pipe 9 and the processing gas supply pipe 2 are connected, and the halogen or halogenated solution is brought into contact. A processing gas containing a hydrogen liquid is generated. For example, by bringing a carrier gas into contact with an aqueous solution of HF, HCl, HBr, HI, HCs, or the like, a processing gas containing these hydrogen halide liquids can be generated.
[0044]
<Surface treatment apparatus using indirect discharge>
FIG. 6 is a schematic explanatory diagram showing the overall configuration of the surface treatment apparatus according to the embodiment of the indirect discharge method of FIG. In the embodiment shown in FIG. 6, the work to be soldered is an IC 10, and the IC 10 is placed on, for example, a conveyor line 14 and sequentially conveyed in the direction from the back surface to the front surface of the drawing. Here, the lead frame 12 of the IC 10 is pre-soldered. Therefore, although the surface of the lead frame 12 is covered with tin (Sn), it is oxidized to tin oxide (SnO). In this embodiment, the solder wettability of the lead frame 12 is improved by substituting tin oxide (SnO) formed on the surface of the lead frame 12 with a halogen compound. In order to surface-treat the lead frame 12 of the IC 10, a surface treatment unit 30, an air supply connection pipe 20 and an exhaust connection pipe 24 connected thereto are provided.
[0045]
A processing gas generated inside the surface treatment unit 30 is introduced into the air supply connecting pipe 20, and the processing gas is supplied to the IC 10, particularly the lead frame, via the air supply portion 22 that spreads in an umbrella shape above the IC 10. 12 is exposed. The exhaust connection pipe 24 is for sucking the processing gas and reaction products exposed to the lead frame 12 and forcibly exhausting them through the surface processing unit 30.
[0046]
Structure of surface treatment unit 30
As shown in FIG. 7, the surface treatment unit 30 includes a processing gas supply pipe 40, a raw material gas supply pipe 41, a power source 50, a plasma generator 60, an exhaust pipe 70, and trapping means in one casing 32. A harmful device 80 is installed.
[0047]
The source gas supply pipe 41 is connected to the upstream side of the plasma generator 60 shown in FIG. 7, and a flow meter 42 is disposed in the middle of the source gas supply pipe 41. This raw material gas supply pipe 41 uses CF in the factory, and CF_FourA raw material gas containing a halogen compound such as is introduced. Further, the open end of the processing gas supply pipe 40 connected to the downstream side of the plasma generation unit 60 is connected to the supply connection pipe 20 shown in FIG.
[0048]
The plasma generator 60 is configured to generate plasma under the atmospheric pressure or a pressure in the vicinity thereof upon receiving power supply from the power supply 50. As shown in FIG. 8, the plasma generator 60 includes a porous insulator 64 disposed between a pair of electrodes 62a and 62b, so that the electrodes 62a and 62b are disposed to face each other. A power source 50 is connected to one electrode 62a, the other electrode 62b is grounded, and an AC voltage or a DC voltage having a relatively low frequency of 50 kHz or less is applied between the electrodes.
[0049]
The power supply 50 applies a relatively low frequency AC voltage or DC voltage of 0 to 50 kHz to the pair of electrodes 62a and 62b, and has a plug 52 to be plugged into an outlet.
[0050]
Thus, the reason why the power supply 50 outputs an AC voltage having a relatively low frequency is as follows. That is, conventionally, in order to generate atmospheric pressure plasma, a large amount of He gas that is relatively easy to generate plasma is required. In this case, the frequency of the alternating voltage applied between the pair of electrodes could be 13.56 MHz which is a commercial frequency. However, without the need for relatively expensive He gas, air or N₂In such an atmosphere, atmospheric pressure plasma could not be generated with an AC voltage of 13.56 MHz, which is a commercial frequency. In this example, atmospheric pressure plasma could be stably generated by applying an AC voltage or a DC voltage having a relatively low frequency of 0 to 50 kHz to the pair of electrodes. This is presumably because the peak-to-peak voltage can be increased in the case of a low-frequency AC voltage, and as a result, energy contributing to plasma generation can be secured.
[0051]
Moreover, the workpiece is 1cm²The supply voltage of the processing gas for processing is set to 0.01 cc to 50 cc, reducing the consumption of the processing gas, and without using expensive He as the carrier gas, the AC voltage applied to the plasma generating electrode By making the frequency of 50 kHz or less as low as possible, it was possible to stably generate plasma under atmospheric pressure or a pressure in the vicinity thereof.
[0052]
In the present embodiment, a carrier gas supply pipe 90 is connected to the process gas supply pipe 40 on the downstream side of the plasma generation unit 60. As a carrier gas introduced into the air supply pipe 90, N₂It is good also as inert gas, such as, but compressed air can also be introduce | transduced. When compressed air is used as the carrier gas, when this compressed air is introduced into the plasma generator 60, oxygen in the compressed air is excited and ozone is generated. When this ozone is exposed to the lead frame 12 of the IC 10, the lead frame 12 is oxidized instead. Therefore, in this embodiment, the processing gas is pumped toward the lead frame 12 by this carrier gas by mixing the processing gas with the processing gas on the downstream side of the plasma generating unit 60.
[0053]
Further, an exhaust pipe 70 for forcibly exhausting the processing gas exposed to the lead frame 12 is provided inside the housing 32 of the surface processing unit 30. The exhaust pipe 70 in the surface treatment unit 30 is connected to the exhaust coupling pipe 24 shown in FIG.
[0054]
Further, the exhaust pipe 70 is connected to an abatement device 80 which is an example of a trap means. Here, the source gas is CF_FourIn this case, when this raw material gas is excited by the plasma generator 60, it is decomposed as follows.
[0055]
2CF_Four→ C₂F₆+ F₂
Fluorine (F₂) Contributes to the surface treatment of the lead frame 12 of the IC 10, but a part thereof is exhausted without contributing to the chemical reaction. However, fluorine (F₂) Is a corrosive gas and cannot be released into the atmosphere. This abatement device 80 removes the above-mentioned corrosion components in the processing gas introduced through the exhaust pipe 70 by adsorption or dissolving in water.
[0056]
Surface treatment method using the surface treatment unit of FIG.
In this first embodiment, compressed air is used as a carrier gas, and a halogen compound such as CF is used as a source gas._FourUsingNoThe The carrier gas and the raw material gas are introduced into the carrier gas supply pipe 90 and the raw material gas supply pipe 41 of the surface treatment unit 30 using equipment arranged in the factory. The flow rates of the source gas and the carrier gas are adjusted by flow meters 42 and 92 provided in the middle of the supply pipes 41 and 90. In this embodiment, the flow rate of the compressed air that is the carrier gas is 20 liters / min, whereas the CF that is the raw material gas_FourIs 50 cc / min. Therefore, the concentration of the raw material gas with respect to the carrier gas is (50 cc / 20 liters) × 100 = 0.25 volume%. Note that the concentration of the source gas may be less than 0.5% by volume, that is, less than 100 cc / min.
[0057]
In this embodiment, the flow rate of the source gas CF is adjusted._FourOnly the plasma generator 60 is introduced. An AC voltage having a relatively low frequency of 10 to 50 kHz is applied to the pair of electrodes 62 a and 62 b provided in the plasma generation unit 60. Therefore, CF which is the source gas_FourEven if the amount of gas is small, and even if there is not a large amount of He gas that makes it easy to start plasma, the AC voltage period becomes longer, so that the plasma can be stably generated at atmospheric pressure or in the vicinity thereof. Can be generated.
[0058]
In the plasma generator 60, CF4 which is a raw material gas_ButFluorine F, a halogen that is excited and decomposed and is highly reactive₂Is generated. In addition, a carrier gas supply pipe 90 is connected to the processing gas supply pipe 40 on the downstream side of the plasma generator 60 so that a relatively large flow rate of carrier gas of 20 liter / min is mixed with the generated processing gas. Thus, this processing gas is pumped by the carrier gas.
[0059]
The processing gas and carrier gas derived from the processing gas supply pipe 40 of the surface processing unit 30 are exposed to the surface of the IC 10 from the supply section 22 via the supply connection pipe 20 connected to the unit 30. become. As a result, the lead frame 12 of the IC 10 is surface-treated according to the following chemical formula.
[0060]
2SnO + 2F₂→ 2SnF₂+ O₂
Here, SnO is an oxide present on the surface of the lead frame 12, and when this comes into contact with the processing gas, the halogen compound (SnF)₂). Further, since the IC 10 that is a workpiece is not exposed to plasma, the IC 10 is not damaged.
[0061]
On the other hand, the processing gas and carrier gas exposed to the lead frame 12 and the reaction product are introduced into the surface unit 30 via the exhaust connection pipe 24. In the surface treatment unit 30, the gas is guided to the abatement device 80 through the exhaust pipe 70.
[0062]
In this abatement apparatus 80, F generated by dividing the processing gas.₂Is adsorbed or dissolved in water and trapped to remove highly corrosive components, and only the remaining gas is exhausted. As a detoxifying device that adsorbs and removes corrosive components, Kanden Eftor (registered trademark), which is a dry exhaust gas treatment device manufactured by Kanto Denka Kogyo Co., Ltd., can be suitably used. When removing the corrosive component by dissolving it in water, the exhaust gas may be passed through water.
[0063]
Therefore, even if the processing gas disposed outside via the abatement device 80 of the surface processing unit 30 is forcibly exhausted using equipment provided in the factory, contamination such as corrosion can be prevented.
[0064]
Structure of the surface treatment unit of FIG.
Next, a surface treatment unit capable of performing surface treatment without using the air supply / exhaust equipment arranged in the factory will be described with reference to FIG.
[0065]
The surface treatment unit 100 shown in FIG. 9 is different from that shown in FIG. 7 in that the housing 32 includes a treatment gas cylinder 44, a carrier gas supply fan 82, an exhaust fan 94, and fan drive units 84 and 96 thereof. It is the point that is further installed. Both fan drive units 84 and 96 are connected to the power source 50.
[0066]
The processing gas cylinder 44 has a CF inside._FourThe raw material gas can be introduced into the plasma generator 60 via the raw material gas supply pipe 41 and the flow meter 42. Since the flow rate of the raw material gas introduced into the plasma generating unit 60 may be a small amount of gas of less than 0.5 volume%, for example, about 0.25 volume% with respect to the carrier gas as described above, a single gas cylinder 44 is used. Thus, the surface treatment of the lead frames 12 of a large number of ICs 10 can be performed.
[0067]
In addition, by disposing the fan 94 in front of the carrier gas supply pipe 90, the air inside the factory can be introduced into the exhaust pipe 70 as compressed air. Further, by adding an exhaust fan 82 after the abatement device 80, the gas around the IC 10 passes through the exhaust pipe 70 and the abatement device 80 inside the connected exhaust pipe 24 and the processing unit 30 shown in FIG. Can be forcibly exhausted.
[0068]
As a result, the surface treatment of the lead frame 12 of the IC 10 can be performed only by connecting the air supply and exhaust connection pipes 20 and 24 to the surface treatment unit 100 without using any air supply / exhaust equipment arranged in the factory. It becomes.
[0069]
Usable process gases
As the source gas introduced into the plasma generating unit 60, the above-mentioned CF_FourAny stable halogen compound represented by, for example, may be used. Halogen or hydrogen halide itself is highly reactive, but has corrosive properties. Therefore, as in the above embodiment, fluorine F that becomes a processing gas only after being excited by plasma.₂It is disassembled into, etc., and it is safe before that._FourIt is better to use a halogen compound such as
[0070]
As halogen compounds used as source gas, all perfluorocarbons such as hexafluoroethane, perfluoropropane, perfluoropentane, octafluorocyclobutane, tetrafluoroethane, trifluoromethane, monobromotrifluoromethane, tetrachloromethane, trichloromonofluoro Examples include methane, dichlorodifluoromethane, chlorotrifluoromethane, sulfur hexafluoride, nitrogen trifluoride, and boron chloride.
[0071]
In addition, it is outside the scope of the present invention, but instead of the above-mentioned gas containing a halogen element, a reducing gas such as hydrogen gas H₂Can be used. This hydrogen gas H₂Is activated by the plasma generator 60, and then the chemical reaction when the processing gas is exposed to the lead frame 12 is as follows.
[0072]
SnO + H₂→ Sn + H₂O
This reducing gas H₂As a result, the oxide SnO present on the surface of the lead frame 12 was reduced, and as a result, the wettability of the lead frame 12 could be improved. In addition, when a reducing gas is used, since no corrosive component is generated as a reaction product, the abatement device 80 is not necessary.
[0073]
Gas that can be used as carrier gas
In the above-described embodiment, compressed air is used as the carrier gas. The use of compressed air is excellent in that the air inside the factory can be used as in the case of using the surface treatment unit 100 of FIG. However, when air is used as the carrier gas, ozone is generated when the air is introduced into the plasma generator 60, and the oxidation phenomenon of the lead frame 12 becomes a problem. Therefore, as shown in FIG. 7 or FIG. 9, it is necessary to connect the carrier gas supply pipe 90 to the processing gas supply pipe 40 on the downstream side of the plasma generating unit 60.
[0074]
On the other hand, if the carrier gas is an inert gas with respect to the surface of the lead frame 12, the carrier gas can be guided to the plasma generator 60. These inert gases include relatively inexpensive nitrogen N.₂And so on.
[0075]
In addition, the use of a carrier gas is preferable in that the activated processing gas can be pumped toward the workpiece 10, but the carrier gas is not necessarily used. In this case as well, the workpiece is 1 cm²The atmospheric pressure plasma for activation necessary for the surface treatment can be stably generated only by introducing a relatively small amount of the processing gas of 0.01 cc to 50 cc as the supply amount of the processing gas for processing. Can do.
[0076]
About the addition of moisture
It has been found that the processing speed is improved when water is added as an additive to the inside of the plasma generating unit 60. In order to add moisture, for example, the source gas may be passed through pure water. The reason for adding moisture is as follows.
[0077]
When water is not added as an additive, for example, CF as a raw material gas_FourWhen is used, the following reaction occurs in the plasma generator 60.
[0078]
2CF_Four→ C₂F₆+ F₂
Fluorine F in the above reaction formula₂Will promote the chemical reaction as an active gas.
[0079]
On the other hand, when water is added as an additive, the following reaction occurs in the plasma generator 60.
[0080]
CF_Four+ 2H₂O → 4HF + CO₂
Thus, when water is added, the generation of acids such as HF can be increased, which is considered to improve the surface treatment speed.
[0081]
When water is added as an additive, the generation of ozone in the plasma generation unit 60 can be suppressed without being limited to simply increasing the processing speed.
[0082]
The relationship between the amount of ozone generated (%) and the humidity is as shown in Table 1 below. However, the ozone generation amount in Table 1 is a value when the ozone generation amount of the dry air is 100%.
[0083]
[Table 1]

As described above, when water is added as an additive, generation of ozone inside the plasma generation unit 60 can be suppressed, and thereby oxidation of the lead frame 12 can be prevented.
[0084]
The addition of water is also effective in the case of thermal decomposition and photodecomposition shown in FIGS.
[0085]
Surface treatment unit without plasma generator
Next, a surface treatment apparatus and method using the method of FIG. 5 will be described with reference to FIG.
[0086]
FIG. 11 shows the overall configuration of the apparatus, and a surface treatment unit 110 to which the air supply connecting pipe 20 and the exhaust connecting pipe 24 are connected is provided as in the case of FIG. The surface treatment unit 110 includes a carrier gas supply pipe 120, a liquid storage unit 130, an exhaust pipe 140, and a detoxifying device 150 inside one housing 112.
[0087]
As the carrier gas supply pipe 120, a first carrier gas supply pipe 120a on the upstream side of the liquid storage section 130, a second carrier gas supply pipe 120b on the downstream side of the liquid storage section 130, and the first and second carriers A third carrier gas supply pipe 120c that connects the gas supply pipes is provided.
[0088]
An aqueous solution of hydrogen halide such as HF or HCl is accommodated in the liquid storage unit 130. For example, N introduced into the liquid storage unit 130 through the first carrier gas supply pipe 120a₂The carrier gas such as is made into a processing gas rich in acidity by coming into contact with the liquid. The processing gas is discharged from the liquid storage unit 130 through the second carrier gas supply pipe 120b and is pumped by the pressure of the carrier gas itself from the third carrier gas supply pipe 120c. It will be derived to the outside.
[0089]
The processing gas rich in acidity is exposed to the lead frame 12 of the IC 10 through the air supply connecting pipe 20 and the air supply unit 22 shown in FIG. Thereby, the surface of the lead frame 12 is surface-treated by the following chemical reaction.
[0090]
When hydrogen fluoride HF is used as the processing gas, the surface treatment is performed according to the following chemical formula.
[0091]
SnO + 2HF → SnF₂+ H₂O
When hydrogen chloride Hcl is used as the treatment gas, the surface treatment is performed according to the following chemical formula.
[0092]
SnO + 2HCl → SnCl₂+ H₂O
Although not within the scope of the present invention, the liquid container 130 has H inside.₂NO_ThreeAn acidic liquid such as ammonia or a basic liquid such as aqueous ammonia can also be accommodated. Nitric acid H₂NO_ThreeWhen is used, the surface treatment is performed according to the following chemical formula.
[0093]
SnO + H₂NO_Three→ SnNO_Three+ H₂O
In addition, other acidic gases such as oxalic acid can be stored in the liquid storage unit 130.
[0094]
In the case where a basic liquid such as ammonia water is stored, the surface treatment is performed according to the following chemical formula.
[0095]
SnO + NH_Three+ 2H₂O → NH⁴⁺[Sn (OH)_Three]^-
On the other hand, the processing gas exposed to the lead frame 12 is introduced into the surface processing unit 110 through the exhaust connection pipe 24. Here, the processing gas rich in acidity or basicity described above is itself a corrosive gas and cannot be released into the atmosphere. Therefore, inside the surface treatment unit 110, the processing gas is guided to the abatement apparatus 150 through the exhaust pipe 140, and the above-described corrosion component in the processing gas is excluded by the exclusion apparatus 150.
[0096]
In the case of the surface treatment unit 110 shown in FIG. 11, as in the case shown in FIG. 9, a configuration that does not use the air supply / exhaust equipment in the factory, that is, an air supply fan, an exhaust fan, and a fan drive device that drives them. Can also be added inside the housing 112.
[0097]
Various types of surface treatment units
Next, various types in which the shapes of the surface treatment units 30, 100 and 110 described above or the shapes of the air supply connection pipe 20 and the exhaust connection pipe 24 connected thereto are changed will be described with reference to FIG.
[0098]
(1) Line type
The line-type surface treatment unit 160 shown in FIGS. 12 and 13 is provided at an upper position facing the plate-like workpiece 500 conveyed by the conveyor line 14. The surface treatment unit 160 includes an air supply / exhaust unit 162 below the housing 161. The air supply / exhaust section 162 forms a double pipe structure with the air supply pipe 164 and the exhaust pipe 166. In this embodiment, an air supply pipe 164 is disposed at the center, an exhaust pipe 166 is disposed around the air supply pipe 164, and a lower end portion of the exhaust pipe 166 has a shape that expands in an umbrella shape.
[0099]
When the workpiece 500 is conveyed intermittently or continuously by the conveyor line 14, the surface of the workpiece 500 is subjected to surface treatment by facing the air supply / exhaust portion 162 of the surface treatment unit. Thereby, it is possible to continuously surface-treat many workpieces 500 on the entire surface of the workpiece 500 while fixing the surface treatment unit 160.
[0100]
(2) Stand type
A stand-type surface treatment unit 200 shown in FIG. 14 includes a housing 201 having a bottom surface on which the surface can be placed. As described above, the raw material gas and / or the carrier gas are introduced into the housing 201, and the exhaust gas is exhausted through the abatement apparatus. The housing 201 is provided with an air supply connection pipe 210 and an exhaust connection pipe 230 extending upward. The air supply connecting pipe 210 is bent and has an air supply portion 220 that opens at the lower end. An umbrella-like diffusion prevention plate 222 for preventing the diffusion of the processing gas is provided around the air supply unit 220. On the other hand, the exhaust connection pipe 230 is formed with an umbrella-shaped exhaust suction portion 240 whose opening area increases as it goes upward at a position facing the diffusion prevention plate 222.
[0101]
14 and 15, as a work, for example, when processing the surface of the tip of the wire 250 from which the covering material at the end has been peeled off, the tip 252 plated in advance of the wire 250 is supplied with air. It is arranged at a position directly below the portion 220. In this way, the front end portion 252 of the wire 250 is surface-treated with the processing gas derived from the air supply unit 220, and the exposed processing gas is removed from the housing 201 via the exhaust suction unit 240 and the exhaust connection pipe 230. Will be led to the device.
[0102]
As described above, by using the stand-type surface treatment unit 200, it is possible to create a local treatment gas atmosphere in the air, and it is possible to easily surface-treat the workpiece such as the wire 250.
[0103]
(3) About rod type
In the embodiment shown in FIGS. 16 and 17, the surface treatment unit 300 itself is configured by a cylindrical casing 301 such as a soldering iron. The air supply connection pipe 310 and the exhaust connection pipe 320 connected to the housing 301 have a double-pipe structure, and the processing gas is led out toward the workpiece 500 by the inner air supply connection pipe 310, and the outer exhaust connection The exposed processing gas is introduced into the housing 301 from the tube 320. From the viewpoint of enlarging the exhaust region, it is preferable that the distal end portion of the exhaust connection pipe 320 has a shape that spreads in an umbrella shape as shown in FIGS.
[0104]
In this way, if the surface treatment unit 300 itself is configured as a rod type, it is possible to perform surface treatment of various workpieces by manually operating the surface treatment unit 300 itself.
[0105]
(4) Toaster type
The surface treatment unit 400 shown in FIGS. 18 and 19 has a slit-like insertion portion 410 into which a plate-like workpiece 500 can be inserted on one surface of the housing 401, for example, the upper surface thereof. An exhaust pipe 420 is connected to the slit-shaped insertion portion 410. On the other hand, for example, both side walls of the slit-like insertion portion 410 are provided with a processing gas supply pipe 430 and a carrier gas supply pipe 440 each having one end opened at the side wall.
[0106]
According to this configuration, by inserting the plate-shaped workpiece 500 into the slit-shaped insertion portion 410 provided on the upper surface of the housing 401, the processing gas is sprayed from both surfaces of the workpiece 500, and the plate-shaped workpiece 500 It is possible to simultaneously treat both surfaces of 500. In the case where only one surface of the workpiece 500 is surface-treated, the processing gas supply pipe 430 may be opened only on one side wall of the slit-shaped insertion portion 410.
[0107]
(5) Batch processing type
FIG. 20 shows an apparatus for processing a large number of workpieces in a batch system. In this apparatus, an air supply connection pipe 20 and an exhaust connection pipe 24 connected to the surface treatment unit 30 (or 100 or 110) are connected to a batch processing box 450. The batch processing box 450 accommodates a large number of workpieces 510 therein. The work 510 to be batch-processed may be, for example, a TAB tape wound in a roll shape in addition to the above-described IC 10, wire 250, and plate-like work 500.
[0108]
According to this batch processing type, it is possible to surface-treat many workpieces 510 at a time. In addition, since the workpiece surface-treated by the treatment method of the present invention can maintain the improved solder wettability for a relatively long time after the surface treatment, the workpiece is stocked until soldering after batch processing. However, good soldering can be performed.
[0109]
【Example】
Next, experimental results for evaluating the solder wettability of the workpiece surface-treated by the method of the present invention will be described with reference to Tables 2 and 3.
[0110]
13 days after the silver was deposited on the crystal oscillator electrode, the tip of the wire to be soldered to the crystal oscillator electrode was surface-treated under various conditions, and soldered (mounted) on the same day. The solder flow evaluation is shown in Table 2 below.
[0111]
[Table 2]

Here, the condition 1 is a case where there is no surface treatment, and the conditions 2 to 6 and 8 are both CF_Four(50cc / min), N as carrier gas₂(20 liters / min) and CF_FourAdded water by passing pure water through. In condition 7, the raw material gas was the same as in condition 2 and the like, and compressed air (20 liters / min) was used as the carrier gas. As plasma generation conditions, the power was relatively low at 50 to 90 W in condition 2 and 250 W in conditions 3 to 8.
[0112]
In Table 2 above, the time indicates the total time of scanning a length of 9 cm. The mounting condition indicates the main voltage and the reserve voltage of the soldering iron at the time of soldering.
[0113]
As shown in Table 2, when compared with Condition 1 where no surface treatment was performed, the results of solder flow were improved under Conditions 2 to 8, and N as a carrier gas.₂Very good results were obtained under conditions 2 to 6 and 8 using.
[0114]
For the case where surface treatment was performed under condition 3 in Table 2 and the case where surface treatment was not carried out, the number of mounts was increased to evaluate the poor solder flow and the electrical characteristics of the crystal oscillator after mounting. The results are shown in Table 3 below.
[0115]
[Table 3]

Frequency f in Table 3₀Indicates the oscillation frequency of the crystal oscillator. Conditions 1 and 3 indicate no treatment, and conditions 2 and 4 indicate surface treatment. Under conditions 1 and 2, 14 days after the silver was deposited on the crystal oscillator electrode, the wire was soldered (mounted) to the crystal oscillator electrode. The surface treatment process of Condition 2 was performed 2 days before the mounting process. Under conditions 3 and 4, a wire was soldered (mounted) to the crystal oscillator electrode 17 days after the silver was deposited on the crystal oscillator electrode. The surface treatment process of Condition 4 was performed 2 days before the mounting process.
[0116]
As is clear from the comparison between the conditions 1 and 2 and the comparison between the conditions 3 and 4, it can be seen that both the solder flow failure rate and the electrical property failure rate are almost halved when the surface treatment is performed.
[0117]
<Comparative Example 1>
The method shown in FIG. 3 is an indirect discharge treatment in which a halogen compound or a halogenated hydrogen halide decomposed by a discharge between a pair of electrodes is used as a treatment gas, and the object to be treated is not directly exposed to plasma. On the other hand, a direct discharge process is known in which a target object is placed on one of a pair of electrodes and the target object is directly exposed to plasma for processing.
[0118]
Table 4 below compares the indirect discharge process of the present embodiment with respect to the wettability of solder with respect to a known direct discharge process and an unprocessed one that is not subjected to any process. . In the indirect discharge treatment of this embodiment, the raw material gas CF_Four500cc / min, carrier gas N₂Was supplied at 20 liters / min. In direct discharge treatment, the raw material gas CF_FourWas supplied at a rate of 500 cc / min, and plasma generation gas He was supplied at a rate of 20 liters / min.
[0119]
[Table 4]

As is apparent from Table 4, it can be seen that the defective rate is remarkably reduced in the indirect discharge treatment of this example. Here, the causes of defects in the indirect discharge treatment are all due to excessive solder flow, and the improvement in solder wettability is no different from a non-defective product.
[0120]
On the other hand, according to the above experimental results, in the direct discharge process, the defect rate at which the solder flow is defective is only 20% lower than that in the unprocessed case. The reason is considered as follows. One of them is that a strong discharge is generated at the lead tip portion of the object to be processed, and it is only partially processed. Another reason is that in the direct discharge process in which the gap between the electrodes is as narrow as several mm, the plasma state changes due to variations in the set state of the object to be processed. If the plasma intensity is too high, the object to be processed will be discolored and the solder flow will be poor.
[0121]
<Comparative example 2>
In each of the above-described embodiments, a processing gas containing halogen or hydrogen halide is used as a processing gas. However, an active species such as a fluorine radical generated in the plasma generation unit is disposed outside the plasma generation unit. There are also known methods for guiding to the body and processing. However, since the active species has a lifetime, the distance from the plasma generation unit to the object to be processed cannot be increased as compared with the indirect discharge treatment of this embodiment.
[0122]
When a 1/4 diameter size (outer diameter 6.35 mm, inner diameter 3.17 mm) generally known as a piping tube is used as the processing gas supply pipe connected to the plasma generation unit, the raw material gas supply flow rate and the tube disconnection The flow rate of the processing gas was calculated from the area. When the supply flow rate of the source gas is 100 cc / min, the flow rate of the processing gas is 21.12 cm / s. Since the lifetime of the fluorine radical is 1/1000 s or less, it disappears at a position 0.0211 cm away from the plasma generation part. When the supply flow rate of the source gas is 30 cc / min, the flow rate of the processing gas is 6.335 cm / s, and disappears at a position 0.0063 cm away from the plasma generation unit.
[0123]
On the other hand, in each of the above-described embodiments, a processing gas containing halogen or hydrogen halide is used as the processing gas. Therefore, even if the object to be processed is placed at a position sufficiently away from the processing gas generation container, Is possible.
[0124]
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view of an embodiment of the present invention schematically showing an apparatus for generating a processing gas by thermal decomposition.
FIG. 2 is a schematic explanatory view of an embodiment of the present invention schematically showing an apparatus for generating a processing gas by photolysis.
FIG. 3 is a schematic explanatory view of an embodiment of the present invention schematically showing an apparatus for generating a processing gas by decomposition by electric discharge.
FIG. 4 is a schematic explanatory view of an embodiment of the present invention schematically showing an apparatus for generating a processing gas by electrolysis.
FIG. 5 is a schematic explanatory diagram of an embodiment of the present invention schematically showing an apparatus for generating a processing gas by contact with a liquid.
FIG. 6 is a schematic explanatory diagram showing an overall configuration of a surface treatment apparatus according to an embodiment of the present invention.
7 is a schematic explanatory view showing an internal configuration of the surface treatment unit shown in FIG. 6. FIG.
8 is a schematic explanatory diagram showing a configuration of a plasma generation unit shown in FIG.
FIG. 9 is a schematic explanatory view showing another embodiment of the surface treatment unit.
FIG. 10 is a schematic explanatory view showing an embodiment in which a processing gas is led out directly toward a workpiece.
FIG. 11 is a schematic explanatory view showing still another embodiment of the surface treatment unit.
FIG. 12 is a schematic explanatory view showing an embodiment in which a line type processing apparatus is constituted by a surface processing unit.
13 is a schematic cross-sectional view showing an air supply / exhaust section of the surface treatment unit shown in FIG.
FIG. 14 is a schematic explanatory view showing an embodiment in which a stand-type processing apparatus is constituted by a surface processing unit.
15 is a schematic cross-sectional view showing an air supply / exhaust section of the surface treatment unit shown in FIG.
FIG. 16 is a schematic explanatory view showing an embodiment in which a bar-type processing apparatus is constituted by a surface processing unit.
17 is a schematic cross-sectional view showing an air supply / exhaust portion of the surface treatment unit shown in FIG.
FIG. 18 is a schematic explanatory view showing an embodiment in which a toaster type processing apparatus is constituted by a surface processing unit.
19 is a schematic cross-sectional view showing an air supply / exhaust portion of the surface treatment unit shown in FIG.
FIG. 20 is a schematic explanatory view showing an embodiment in which a batch processing type processing apparatus is constituted by a surface processing unit.
[Explanation of symbols]
1 Container for processing gas generation
2 Processing gas supply pipe
3 Raw material gas supply pipe
4 Heater
5 UV lamp
6 Plasma generator
7 Partition plate
8a, 8b electrode
9 Carrier gas supply pipe
10, 250, 500, work
20, 210, 310 Supply connection pipe
24, 230, 320 Exhaust connection pipe
30, 100, 110, 160, 200, 300, 400 Surface treatment unit
32, 112, 161, 201, 301, 401
40, 164, 430 Process gas supply pipe
42, 92 Flow meter
44 Gas cylinder
50 power supply
60 Plasma generator
62a, 62b electrode
70, 140, 166, 420 Exhaust pipe
80, 150 abatement equipment
82 Exhaust fan
90, 120 Carrier gas supply pipe
94 Air supply fan
130 Liquid container

Claims (13)

Decomposing a halogen compound in an atmosphere containing moisture to generate a treatment gas containing hydrogen halide;
Contacting the surface of the object to be processed with the processing gas, and treating the surface of the object to be processed;
A surface treatment method characterized by comprising: In claim 1,
A surface treatment method, wherein the source gas is excited and decomposed by a pair of electrodes to which an AC voltage or a DC voltage having a low frequency of 50 kHz or less is applied under atmospheric pressure or a pressure in the vicinity thereof. In claim 1 or 2,
A surface treatment method, wherein the treatment gas is pumped by a carrier gas and brought into contact with the object to be treated. In claim 3,
A surface treatment method comprising mixing the carrier gas with the treatment gas after the halogen compound decomposition step. Contacting a carrier gas with an aqueous solution of hydrogen halide to generate a treatment gas containing a liquid of hydrogen halide;
Contacting the surface of the object to be processed with the processing gas, and treating the surface of the object to be processed;
A surface treatment method characterized by comprising: In any one of Claims 1 thru | or 5,
Forcibly exhausting the processing gas and reaction product supplied toward the object to be processed;
Trapping the process gas or the reaction product during exhaustion; and
The surface treatment method further comprising: In any one of Claims 1 thru | or 6.
A surface treatment characterized in that the treatment gas is brought into contact with the surface of the object to be treated, and the oxide on the surface of the object to be treated is replaced with a halogen compound to improve solder wettability on the surface. Method. In a surface treatment apparatus for treating the surface of an object to be treated,
A source gas supply means for supplying a source gas containing a halogen compound;
A processing gas generating means for generating a processing gas containing hydrogen halide by decomposing the halogen compound by discharge in an atmosphere containing moisture;
A processing gas supply means for guiding the processing gas from the processing gas generation means to the surface of the object to be processed;
A surface treatment apparatus comprising: In claim 8,
The processing gas generation means includes
A power supply that outputs an AC voltage or a DC voltage with a low frequency of 50 kHz or less;
A plasma generation unit comprising a pair of electrodes to which the voltage is applied, and inducing plasma under atmospheric pressure or a pressure in the vicinity thereof;
A surface treatment apparatus comprising: In claim 8 or 9,
A surface treatment apparatus, further comprising a carrier gas supply unit connected to the source gas supply unit and configured to supply a carrier gas mixed with the source gas. In any one of Claims 8 thru | or 10.
The surface treatment apparatus further comprising a carrier gas supply unit connected to the process gas supply unit and configured to supply a carrier gas mixed with the process gas. A processing gas generation means for generating a processing gas containing hydrogen halide by bringing a carrier gas into contact with an aqueous solution containing halogen hydrogen;
A processing gas supply means for guiding the processing gas from the processing gas generation means to the surface of the object to be processed;
A surface treatment apparatus comprising: In any one of Claims 8 thru | or 12.
An exhaust means for forcibly exhausting the processing gas and reaction product supplied toward the object to be processed;
Trap means for trapping the processing gas or the reaction product during exhaustion;
The surface treatment apparatus further comprising:

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