KR930002525B1 - Solder - Google Patents
Solder Download PDFInfo
- Publication number
- KR930002525B1 KR930002525B1 KR1019900019215A KR900019215A KR930002525B1 KR 930002525 B1 KR930002525 B1 KR 930002525B1 KR 1019900019215 A KR1019900019215 A KR 1019900019215A KR 900019215 A KR900019215 A KR 900019215A KR 930002525 B1 KR930002525 B1 KR 930002525B1
- Authority
- KR
- South Korea
- Prior art keywords
- solder
- laser diode
- silver
- tin
- lead
- Prior art date
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
Abstract
Description
제1도는 종래의 땜납이 부착된 레이저 다이오드의 구조도.1 is a structural diagram of a conventional laser-attached laser diode.
제2도는 본 발명의 땜납이 부착된 레이저 다이오드의 구조도.2 is a structural diagram of a soldered laser diode of the present invention.
제3도는 시효(Aging)에 따른 특성변화 그래프.3 is a graph showing a characteristic change according to aging.
본 발명은 레이저 다이오드 부착용 땜납(Solder)에 관한 것으로, 특히 레이저 다이오드 칩의 부착능력과 수명연장을 향상시키는 땜납에 관한 것이다.BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to solders for attaching laser diodes, and more particularly to solders for improving the adhesion capability and life extension of laser diode chips.
종래의 레이저 다이오드 칩(Chip)을 패키지(Package)에 부착시 사용되는 땜납은 제1도에 나타난 바와같이 실리콘 웨이퍼(1)에 Cr/Ni/Au로 된 층(2)을 순차적으로 증착시키고 그 위에 열팽창 계수가 큰 In(인듐)과 전단응력이 큰 Au(금) 및 Su(주석) 또는 Au(금) 및 Ge(게르마늄)으로 된 땜납층(3)을 약 2-3μm두께로 증착 도포시킨 후 그면에 레이저 다이오드 칩은 200-360℃ 온도로 N2분위기 중에서 패키지에 부착하여 이를 다시 실온으로 냉각 후 조립공정 순서에 따라 리드선을 연결하게 된다.Solder used for attaching a conventional laser diode chip to a package sequentially deposits a layer 2 of Cr / Ni / Au on the silicon wafer 1 as shown in FIG. A solder layer (3) of In (indium) with a high coefficient of thermal expansion and Au (gold) and Su (tin) or Au (gold) and Ge (germanium) having a large thermal stress was deposited and deposited to a thickness of about 2-3 μm. After that, the laser diode chip is attached to the package in an N 2 atmosphere at a temperature of 200-360 ° C., and then cooled to room temperature, and then connected to the lead wire according to the assembly process sequence.
이와 같은 종래 기술에서는 In 또는 Au, Sn을 사용시 In, Sn에 Au가 용융되는 땜납 용식 현상이 생겨 InAu4, In2Au, InAu9, In4Au 또는 AuSn2, AuSn4ALT6Sn의 금속간 화합물이 발생하며 이들로 인하여 레이저다이오드와의 결합력이 취약해지고, 이로인한 응력이 레이저 다이오드에 전달되어 레이저 다이오드 칩의 노화현상이 급속히 일어나거나, 저항 값 증가로 인하여 소모전력이 증가하게 된다.In this conventional technique, when soldering In, Au, or Sn, Au is melted in Au, and a solder melt phenomenon occurs. InAu 4 , In 2 Au, InAu 9 , In 4 Au or AuSn 2 , AuSn 4 ALT 6 Sn between metals Compounds are generated and the bonding strength with the laser diode is weakened, and the stress is transmitted to the laser diode, so that the aging phenomenon of the laser diode chip occurs rapidly or the power consumption increases due to the increase in the resistance value.
또한 땜납이동(Solder migration)현상으로 인해 레이저 다이오드 칩 자체가 사용도중 쉽게 단락되는 사고 등이 발생하게 된다.Also, due to solder migration, the laser diode chip itself is easily shorted during use.
뿐만 아니라 Au와 Ge(88 : 12중량비)을 사용시 공융점이 356℃로 매우 높기 때문에 레이저 다이오드 칩의 금속이 쉽게 산화될 우려가 있으며 또한 열에 의한 레이저 다이오드의 노화가 급격이 일어나는 등의 문제점이 있다.In addition, when Au and Ge (88: 12 weight ratio) are used, the eutectic point is very high at 356 ° C., so that the metal of the laser diode chip may be easily oxidized, and there is a problem of rapid aging of the laser diode due to heat.
이에 본 발명은 기존의 레이저 다이오드 칩의 접착용 땜납인 In, AuSn, AuGe을 Pb, Sn, Ag로 대체하므로서 상기와 같은 문제점을 해결하는데 목적이 있다.Accordingly, an object of the present invention is to solve the above problems by replacing In, AuSn, AuGe, which is an adhesive solder of a conventional laser diode chip, with Pb, Sn, Ag.
이하 본 발명 제2도에 따라 설명한다.Hereinafter, the present invention will be described with reference to FIG. 2.
제2도는 본 발명의 땜납이 적층된 레이저 다이오드 구조를 나타낸 것으로서, 실리콘-웨이퍼(1) 상에Cr/Ni(2')을 각각 500-1000°/4000-5000Å 정도씩 증착한 후 그 상부에 땜납층(3')으로 Pb : Sn : A9를 85-91 : 8-12 : 1-3의 중량%로 혼합하여 균일한 두께로 증착하여서 됨을 특징으로 한 것이다.2 shows a laser diode structure in which the solder of the present invention is stacked, and deposited Cr / Ni (2 ′) on the silicon wafer 1 by 500-1000 ° / 4000-50004000, respectively. The solder layer 3 'is characterized in that Pb: Sn: A9 is mixed at a weight percent of 85-91: 8-12: 1-3 and deposited to a uniform thickness.
이와 같이 된 구조에서 본 발명의 요지인 레이저 다이오드 칩의 부착용 땜납 금속을 상기와 같은 조성물로 하므로서, Sn에 의한 Au의 용융 및 땜납이동(Solder migration)을 최소화 하였으며, 열전도도가 우수한 Ag의 젖음(Wetting)을 향상시키기 의해 Pb함량을 크게 하였다.In this structure, the solder metal for the attachment of the laser diode chip, which is the gist of the present invention, has the composition as described above, thereby minimizing Au melting and solder migration by Sn and excellent wettability of Ag. Pb content was increased by improving the wetting.
또한 본 발명에 따라 레이저 다이오드 칩의 부착 온도는 약 260℃로서 In의 경우보다는 높지만 Au 및 Sn,An 및 Ge의 부착 온도보다는 훨씬 낮아 접착온도에 의한 레이저 다이오드 칩의 손상을 방지할 수 있으며, 또한 Su의 함량이 적기 때문에 Sn에 의한 위스커 성장(Whisker Growth) 현상으로 인해 발생하는 소자 단락 현상을 억제하여 소자의 안정된 동작을 지속할 수 있다.In addition, according to the present invention, the deposition temperature of the laser diode chip is about 260 ° C., which is higher than that of In, but much lower than that of Au, Sn, An, and Ge, thereby preventing damage to the laser diode chip due to the adhesion temperature. Since the content of Su is small, it is possible to suppress device short circuit caused by Whisker Growth due to Sn, thereby maintaining stable operation of the device.
제3도의 특성도는 본 발명이 적용된 소자의 시효측정(Aging Test : 물질을 적당한 온도에서 장시간 방치하여 재료의 특성이 시간의 경과에 따라 변해지는 것)한 결과로써, X축 방향은 동작시간이며, Y축은 동작전류를 나타낸 것으로, 본 발명의 Pb : Sn : Ag=88 : 10 : 2로 부착된 레이저 다이오드는 시간경과에 따라 변화가 없었으나 (A), In(B) 또는 Su(C)으로 부착된 레이저 다이오는 시간경과에 따라 특성이 변화됨을나타내었다.The characteristic diagram of FIG. 3 is the result of aging test of the device to which the present invention is applied (Aging Test: the material is changed for a long time by leaving the material at a proper temperature for a long time), and the X-axis direction is the operation time. , Y-axis represents the operating current, the laser diode attached with Pb: Sn: Ag = 88: 10: 2 of the present invention did not change over time (A), In (B) or Su (C) The laser diode attached to the device showed that the characteristics changed over time.
따라서 본 발명의 땜납이 시효특성이 우수하다. 이상에서와 같이 된 본 발명에 대한 시효(Aging)변화현상을 알아 보기 의하여 땜납층(3')의 증착이 완료된 웨이퍼를 패키지(Package)의 스템(STEM)상에 알맞은 두께로 하였다.Therefore, the solder of this invention is excellent in an aging characteristic. By examining the aging change phenomenon according to the present invention as described above, the wafer on which the deposition of the solder layer 3 'was completed was made to have an appropriate thickness on the stem of the package.
본 실험에서는 W600×L600×H200(μm8)로 절단하여 본 발명으로 조립된 시편에 대한 시효(Aging) 변화(물질을 적당한 온도에서 장시간 방치하여 재료의 특성이 시간의 경과에 따라 변하는 것)를 비교하였다.In this experiment, the aging change (the property of the material changed over time by leaving the material at a suitable temperature for a long time) was cut to W600 × L600 × H200 (μm 8 ) and assembled into the present invention. Compared.
상술한 바와 같이 Pb : Sn : Ag를 85-91 : 8-12 : 1-3으로 제한한 이유는 Sn중량이 많아지게 되면 반드시 위스커 성장(Whisker growth)용액으로부터 화합물의 분해가 생겨 결정이 되는 현상이 발생하게 되고, 이 위스커 성장은 In의 경우에는 소자에 전류를 인가할 때만 나타나나 Sn의 경우는 전류를 인가하지 않을때도 나타난다.As described above, the reason why Pb: Sn: Ag is limited to 85-91: 8-12: 1-3 is that when the Sn weight increases, the compound must be decomposed and crystallized from the whisker growth solution. This whisker growth appears only when applying a current to the device in case of In, but also when no current is applied in case of Sn.
따라서 위스커 성장을 방지하기 위해 Sn중량을 줄여야 하나 Sn중량이 줄어들 경우에는 땜납이 리드프레임(leadfrane)에 젖어드는 (wetting) 성질이 낮아져 본딩력이 상당히 취약해진다.Therefore, in order to prevent whisker growth, the weight of Sn should be reduced, but if the weight of Sn is reduced, the wetting property of the solder on the lead frame is reduced, so that the bonding strength becomes weak.
그러므로 Sn중량을 감소시키면서 젖어드는 성질의 저하를 방지하는 물질인 Ag를 미량(3wt/%이하) 첨가하여야 하고, 만약, Ag 첨가량이 과다하게 되면 Ag의 원자둘레에 Sn이 불균일하게 형성되면서 Ag2Sn의 금속간 화합물이 형성되고, 이 금속간 화합물은 어느 시점이상에서는 저항이 급격히 증가하여 정상동작을 하던 소자가 갑자기 다운되어 버리게 된다.Therefore, should the material of Ag to prevent the deterioration of properties lifting wet reducing the Sn wt adding a very small amount (3wt /% or less), and if, when the Ag addition amount excessive as to form the Sn is not uniform on the atomic periphery of Ag Ag 2 An intermetallic compound of Sn is formed, and the intermetallic compound suddenly increases in resistance over a certain point of time, and the device in normal operation suddenly goes down.
이러한 현상을 반도체 레이저 다이오드에서는 "Thenal runaway"라 한다.This phenomenon is called "Thenal runaway" in semiconductor laser diodes.
따라서, Ag는 3wt/% 이내로 한정하고, Sn은 위스커 성장을 제한하기 위하여 12wt/% 이내로 한정하게 된 것이며, 실험결과 가장 적당한 중량비(%)는 Pb : Sn : Ag = 88 : 10 : 2이다.Therefore, Ag is limited to within 3wt /%, Sn is limited to within 12wt /% in order to limit whisker growth, and the most suitable weight ratio (%) as a result of the experiment is Pb: Sn: Ag = 88: 10: 2.
Claims (2)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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KR1019900019215A KR930002525B1 (en) | 1990-11-26 | 1990-11-26 | Solder |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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KR1019900019215A KR930002525B1 (en) | 1990-11-26 | 1990-11-26 | Solder |
Publications (2)
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KR920009498A KR920009498A (en) | 1992-06-25 |
KR930002525B1 true KR930002525B1 (en) | 1993-04-03 |
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KR1019900019215A KR930002525B1 (en) | 1990-11-26 | 1990-11-26 | Solder |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101920405A (en) * | 2010-08-23 | 2010-12-22 | 中国电力科学研究院 | Tin-lead-based composite solder for galvanized steel ground grid and preparation method thereof |
-
1990
- 1990-11-26 KR KR1019900019215A patent/KR930002525B1/en not_active IP Right Cessation
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101920405A (en) * | 2010-08-23 | 2010-12-22 | 中国电力科学研究院 | Tin-lead-based composite solder for galvanized steel ground grid and preparation method thereof |
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Publication number | Publication date |
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KR920009498A (en) | 1992-06-25 |
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