JP2665926B2 - Printed circuit board reflow method - Google Patents
Printed circuit board reflow methodInfo
- Publication number
- JP2665926B2 JP2665926B2 JP63049590A JP4959088A JP2665926B2 JP 2665926 B2 JP2665926 B2 JP 2665926B2 JP 63049590 A JP63049590 A JP 63049590A JP 4959088 A JP4959088 A JP 4959088A JP 2665926 B2 JP2665926 B2 JP 2665926B2
- Authority
- JP
- Japan
- Prior art keywords
- printed circuit
- circuit board
- cream solder
- preheating
- reflow
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明はプリント基板に塗布したクリームはんだを加
熱溶融してはんだ付けするリフロー方法に関する。Description: TECHNICAL FIELD The present invention relates to a reflow method in which cream solder applied to a printed circuit board is melted by heating.
クリームはんだを印刷塗布したプリント基板の加熱装
置としては、トンネル内に赤外線ヒータや熱風吹出装置
を備えたリフロー炉、レーザや赤外線を集光して照射す
る熱線照射装置、高沸点溶剤を気化させた蒸気槽等であ
るが、リフロー炉以外の加熱装置は急加熱となるため、
プリント基板や電子部品にヒートショックを与え、プリ
ント基板を熱損傷させたり電子部品の機能を劣化させる
ばかりでなく、クリームはんだ中のフラックスを突沸さ
せてクリームはんだを不必要な箇所に飛散させたり、或
いは電子部品が立ち上るマンハッタン現象を起こさせて
しまうものである。しかるにリフロー炉は予備加熱と本
加熱が連続して行えることから他の加熱装置のような問
題を起こすことが少なく、クリームはんだを塗布したプ
リント基板のリフローには最適なものと言える。As a heating device for the printed circuit board coated with cream solder, a reflow furnace equipped with an infrared heater and a hot air blowing device in the tunnel, a heat ray irradiation device that focuses and irradiates laser and infrared rays, and a high boiling solvent was vaporized Although it is a steam tank, etc., since heating devices other than the reflow furnace are rapidly heated,
In addition to applying heat shock to printed circuit boards and electronic components, not only heat damage to the printed circuit board and deterioration of the function of the electronic components, but also bumping the flux in the cream solder to splash the cream solder to unnecessary parts, Alternatively, it causes a Manhattan phenomenon in which electronic components rise. However, since the reflow furnace can perform preheating and main heating continuously, it does not cause a problem like other heating devices, and can be said to be optimal for reflow of a printed circuit board coated with cream solder.
従来のリフロー方法はプリント基板をリフロー炉内に
挿入後、直ぐにプリント基板のはんだ付け部を150℃位
の温度に昇温させ、該温度で一定時間予備加熱後、クリ
ームはんだの溶融する温度（クリームはんだ中の粉末は
んだが63Sn−Pbであれば約200℃）まで昇温させる本加
熱を行い、その後、冷風で冷却していたものである。つ
まり、従来のリフロー方法に用いられていたリフロー炉
の温度プロファイル（プリント基板のはんだ付け部にお
ける温度変化）は第２図に示すように平行状態の予備加
熱（約150℃）に続いて山形の本加熱（約200℃）となっ
ていた。In the conventional reflow method, immediately after the printed circuit board is inserted into the reflow furnace, the temperature of the soldered portion of the printed circuit board is raised to a temperature of about 150 ° C. The main heating was performed to raise the temperature to about 200 ° C. if the powder solder in the solder was 63Sn—Pb, and then cooled with cold air. In other words, the temperature profile of the reflow furnace (temperature change at the soldered portion of the printed circuit board) used in the conventional reflow method has a mountain-like shape following the parallel preheating (about 150 ° C.) as shown in FIG. Main heating (about 200 ° C) was performed.
ところで、第２図に示すようなプロファイルを有する
リフロー炉で加熱する従来のリフロー方法ではプリント
基板に印刷塗布したクリームはんだの形状が崩れ、クリ
ームはんだが所定のはんだ付け部以外に広がってしまう
という“ダレ”を起こすことがあった。クリームはんだ
がダレを起こすと隣接したはんだ付け部に塗布したクリ
ームはんだ同志が合流し、そのまま溶融・凝固してブリ
ッジを形成することがある。電子機器では一箇所でもブ
リッヂを形成すると電子機器としての機能が全く損なわ
れてしまうものである。By the way, in the conventional reflow method of heating in a reflow furnace having a profile as shown in FIG. 2, the shape of the cream solder printed and applied on the printed circuit board is broken, and the cream solder spreads to a portion other than a predetermined soldering portion. "Dare" may occur. When the cream solder causes sagging, the cream solder applied to the adjacent soldering portions may merge and melt and solidify as it is to form a bridge. When a bridge is formed even in one place in an electronic device, the function as the electronic device is completely impaired.
本発明はプリント基板に塗布したクリームはんだのリ
フロー時、クリームはんだがダレを起こさないリフロー
方法を提供することにある。An object of the present invention is to provide a reflow method in which the cream solder does not sag when the cream solder applied to the printed circuit board is reflowed.
本発明者らが従来のリフロー方法におけるクリームは
んだのダレの状態について観察したところ、予備加熱の
段階でダレの起こることが分かった。つまり、クリーム
はんだのフラックスは松脂のような非晶質の材料を溶剤
で溶解したものであるため、クリームはんだは常温では
或る程度の粘度があり、印刷塗布形状を保っていられる
が、予備加熱で加熱が行われるとフラックスの粘度が下
がって流動してしまうものである。従って、初めからフ
ラックス中の液体成分である溶剤が少なければ予備加熱
時点で粘度が下がらずクリームはんだのダレも起こりに
くくなるが、溶剤が少ないと粘度が高くなるため、印刷
塗布性が極めて悪くなってしまう。The present inventors have observed the state of dripping of the cream solder in the conventional reflow method, and found that dripping occurs at the stage of preheating. In other words, since the flux of cream solder is a material obtained by dissolving an amorphous material such as rosin with a solvent, the cream solder has a certain degree of viscosity at room temperature and can maintain the printed coating shape. If the heating is performed in step (1), the viscosity of the flux decreases and the flux flows. Therefore, if the solvent as the liquid component in the flux is small from the beginning, the viscosity does not decrease at the time of preheating and the dripping of the cream solder is unlikely to occur. Would.
それ故、クリームはんだとしては印刷塗布時に所定の
粘度があり、予備加熱で適当に溶剤が蒸発してダレを起
こさないものが良く、本発明出願人は斯様なクリームは
んだを既に提案してきた（特願昭63−35021号）。該ク
リームはんだは蒸気圧の高い溶剤と低い溶剤を二種以上
混合したもので、予備加熱の段階で蒸気圧の高い溶剤を
蒸発させることによりダレを防ごうとするものである。
しかるに、本発明者らは更にクリームはんだのダレ防止
をリフロー方法でも解決しようと試みた次第である。Therefore, it is preferable that the cream solder has a predetermined viscosity at the time of printing and application, and the solvent is appropriately evaporated by preheating so as not to cause dripping. The applicant of the present invention has already proposed such a cream solder ( Japanese Patent Application No. 63-35021). The cream solder is a mixture of two or more solvents having a high vapor pressure and a solvent having a low vapor pressure, and is intended to prevent dripping by evaporating the solvent having a high vapor pressure in a preheating stage.
However, the present inventors have further attempted to solve the problem of sagging of the cream solder by a reflow method.
従来のリフロー方法およびリフロー炉では、プリント
基板をリフロー炉に挿入後、プリント基板のはんだ付け
部の温度が直ぐに150℃位になるように予備加熱を行っ
ていたものであるが、この様な加熱ではクリームはんだ
中の溶剤が蒸発する前にクリームはんだが軟化してダレ
てしまう。In the conventional reflow method and reflow furnace, after the printed circuit board is inserted into the reflow furnace, preheating is performed immediately so that the temperature of the soldered portion of the printed circuit board becomes about 150 ° C. Then, before the solvent in the cream solder evaporates, the cream solder softens and sags.
本発明者らは低い温度で予備加熱するとクリームはん
だがダレを起こさず溶剤が蒸発しやすくなることを見い
出し本発明を完成させた。The present inventors have found that when preheating is performed at a low temperature, the cream solder does not sag and the solvent easily evaporates, thus completing the present invention.
本発明は、クリームはんだが塗布されたプリント基板
をリフロー炉で加熱してはんだ付けを行うプリント基板
のリフロー方法において、クリームはんだが塗布された
プリント基板のはんだ付け部を70〜100℃で一定時間一
次予備加熱を行い、さらに120〜160℃で一定時間二次予
備加熱を行った後、クリームはんだを溶融させる本加熱
を行うことを特徴とするプリント基板のリフロー方法で
ある。The present invention relates to a printed circuit board reflow method in which a printed circuit board on which cream solder is applied is heated in a reflow furnace to perform soldering. This is a method of reflowing a printed circuit board, comprising performing primary preheating, further performing secondary preheating at 120 to 160 ° C. for a certain time, and then performing main heating to melt cream solder.
本発明プリント基板のリフロー方法では、一次予備加
熱が70℃よりも低いとクリームはんだ中の溶剤の蒸発が
遅く、しかるに100℃を越えると該溶剤の蒸発よりもク
リームはんだの軟化が早くなってクリームはんだがダレ
てしまう。In the method of reflowing a printed circuit board of the present invention, when the primary preheating is lower than 70 ° C., the evaporation of the solvent in the cream solder is slow. Solder is dripped.
一次予備加熱よりも高い温度の二次予備加熱は、プリ
ント基板をはんだ付け温度に近づけて、クリームはんだ
のはんだ付け性を良好にするとともに、プリント基板や
電子部品を高い温度の本加熱からのヒートショックを和
らげるために行うもので、これが120℃よりも低いとは
んだ付け性に寄与しないばかりかヒートショックを和ら
げる効果も少ない。また二次予備加熱が160℃よりも高
いと、プリント基板や電子部品の高温にさらされる時間
（本加熱時間＋高温予備加熱時間）が長くなって好まし
くない。The secondary preheating at a higher temperature than the primary preheating brings the printed circuit board closer to the soldering temperature, improves the solderability of the cream solder, and heats the printed circuit board and electronic components from the main heating at a higher temperature. This is performed to reduce the shock. If the temperature is lower than 120 ° C., not only does not contribute to the solderability, but also the effect of reducing the heat shock is small. On the other hand, if the secondary preheating is higher than 160 ° C., the time during which the printed circuit board or the electronic component is exposed to a high temperature (main heating time + high temperature preheating time) is not preferable.
下記のリフロー炉、プリント基板、印刷冶具、クリー
ムはんだを用い、実施例、比較例におけるリフロー方法
の実験を行った。Using the following reflow furnace, printed circuit board, printing jig, and cream solder, an experiment of a reflow method in Examples and Comparative Examples was performed.
○リフロー炉：トンネルの上下に多数の赤外線ヒータが 設置されていて、それぞれの赤外線ヒータは温度調整 が可能となっている。○ Reflow furnace: Many infrared heaters are installed above and below the tunnel, and each infrared heater can be adjusted in temperature.
○プリント基板：ピッチ間隔が0.6mmとなっている100ピ ンのQFPを搭載するためのランドが設置されたセラミ ック製基板。○ Printed circuit board: A ceramic board on which a land for mounting a 100-pin QFP with a pitch interval of 0.6 mm is installed.
○印刷治具：前記100ピンのQFPのランドと同位置に0.3 ×１（mm）の矩形の孔が穿設された0.2mm厚のメタル マスク。Printing jig: 0.2 mm thick metal mask with a 0.3 × 1 (mm) rectangular hole drilled at the same position as the 100-pin QFP land.
○クリームはんだ：一般に市販のクリームはんだ（千住 金属工業株式会社製SPT−60−63、Ｆ−10％） 実施例 リフロー炉を第１図に示すようなプロファイルが得ら
れるように調整してクリームはんだのリフローを行っ
た。○ Cream solder: Generally commercially available cream solder (SPT-60-63, F-10%, manufactured by Senju Metal Industry Co., Ltd.) Was reflowed.
比較例 リフローを第２図に示すような従来のリフロー方法に
用いられていたプロファイルに調整してクリームはんだ
のリフローを行った。Comparative Example Reflow of the cream solder was performed by adjusting the reflow to the profile used in the conventional reflow method as shown in FIG.
実験結果 実施例ではブリッジの形成は皆無であったが比較例で
はブリッヂが多数発生していた。Experimental Results In the example, no bridge was formed, but in the comparative example, many bridges were generated.
本発明によればプリント基板に印刷塗布したクリーム
はんだがダレないため、リフロー後のプリント基板には
ブリッヂの発生も無くなり、信頼あるはんだ付け部が得
られる。According to the present invention, since the cream solder printed and applied to the printed circuit board does not sag, no bridging occurs on the printed circuit board after reflow, and a reliable soldered portion can be obtained.
第１図は本発明のリフロー方法におけるリフロー炉の温
度プロファイル、第２図は従来のリフロー方法における
リフロー炉の温度プロファイルである。FIG. 1 is a temperature profile of a reflow furnace in a reflow method of the present invention, and FIG. 2 is a temperature profile of a reflow furnace in a conventional reflow method.
Claims (1)
をリフロー炉で加熱してはんだ付けを行うプリント基板
のリフロー方法において、クリームはんだが塗布された
プリント基板のはんだ付け部を70〜100℃で一定時間一
次予備加熱を行い、さらに120〜160℃で一定時間二次予
備加熱を行った後、クリームはんだを溶融させる本加熱
を行うことを特徴とするプリント基板のリフロー方法。1. A method of reflowing a printed circuit board to which a solder paste is applied by heating a printed board to which a cream solder is applied in a reflow furnace, wherein a soldering portion of the printed board to which the cream solder is applied is maintained at 70 to 100 ° C. A method for reflowing a printed circuit board, comprising: performing primary preheating for a predetermined time, further performing secondary preheating at 120 to 160 ° C. for a predetermined time, and then performing main heating for melting cream solder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63049590A JP2665926B2 (en) | 1988-03-04 | 1988-03-04 | Printed circuit board reflow method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63049590A JP2665926B2 (en) | 1988-03-04 | 1988-03-04 | Printed circuit board reflow method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01225195A JPH01225195A (en) | 1989-09-08 |
| JP2665926B2 true JP2665926B2 (en) | 1997-10-22 |
Family
ID=12835445
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63049590A Expired - Lifetime JP2665926B2 (en) | 1988-03-04 | 1988-03-04 | Printed circuit board reflow method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2665926B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04111388A (en) * | 1990-08-30 | 1992-04-13 | Fujitsu Ltd | Manufacture of semiconductor device, and heating furnace |
| JP2590613B2 (en) * | 1991-02-04 | 1997-03-12 | 松下電器産業株式会社 | Local soldering method using light beam etc. |
| JPH0621636A (en) * | 1992-07-03 | 1994-01-28 | Fujitsu Ltd | Soldering of electronic circuit part to board |
| JP2576004B2 (en) * | 1992-09-14 | 1997-01-29 | 株式会社メルコ | Reflow furnace for cream solder welding and solder welding method using cream solder |
| US7026582B2 (en) | 2003-05-07 | 2006-04-11 | Visteon Global Technologies, Inc. | Vector transient reflow of lead free solder for controlling substrate warpage |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56167395A (en) * | 1980-05-27 | 1981-12-23 | Mitsubishi Electric Corp | Method of mounting part on circuit board |
| JPS5730398A (en) * | 1980-07-30 | 1982-02-18 | Hitachi Ltd | Soldering device |
-
1988
- 1988-03-04 JP JP63049590A patent/JP2665926B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01225195A (en) | 1989-09-08 |
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