- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄373261 > REPORT Report - Lead (Pb)-Free Packaging Strategy 2000-2003 PDF資料下載
參數(shù)資料
| 型號： | REPORT |
| 英文描述： | Report - Lead (Pb)-Free Packaging Strategy 2000-2003 |
| 中文描述： | 報告-無鉛（Pb）2000-2003免費包裝策略 |
| 文件頁數(shù)： | 11/16頁 |
| 文件大小： | 188K |
| 代理商： | REPORT |
became liquid below 225°C and have small pasty ranges. (Eutectic alloys have a distinct melting temperature at
which the alloy goes directly from the solid to the liquid state. Non-eutectic alloys have a temperature at which
some phase begins to melt and another at which all phases have melted; the two temperatures are the solidus and
liquidus temperatures respectively. The range between the solidus and liquidus temperature is the “pasty” range in
-
7
-
Selected Pb-Free Alloys
Composition
Melting/Liquidus
Temperature (
°
C)
Alloy Type
Companies
Evaluating or Using
Sn-37Pb
Sn-3.5Ag
Sn-0.7Cu
Sn-58Bi
Sn-3Ag-0.5Cu
Sn-3Ag-2Bi
Sn-2.6Ag-0.8Cu-0.5Sb
Sn-3.4Ag-4.8Bi
Sn-2.8Ag-20In
Sn-3.5Ag-0.5Cu-1Zn
183
221
227
139
217
220
211
210
187
221
Eutectic (Standard)
Eutectic
Eutectic
Eutectic
Non-eutectic
Non-eutectic
Non-eutectic
Non-eutectic
Non-eutectic
Non-eutectic
Siemens
Nortel
Matsushita
Siemens,Nortel
Fujitsu
Sony (+ Ge)
Matsushita
NEC
which the material is a
mixture of solid and liquid
phases.) Since the list of
candidate materials does
include non-eutectic as
well as eutectic alloys,
the size of the pasty
range is of concern. A
smaller
pasty
allows for easier control
of the solder processing
temperature. The alloys
in the final NCMS list, as
well as Sn/37Pb, are
shown in the Table 2.
Although none of the
range
materials on the list can truly be said to be drop-in replacements for the eutectic Sn/Pb alloy (Sn/37Pb), the
materials on the short list do have many characteristics that may be in fact better than the standard alloy. One
particular eutectic alloy that had interested several companies (Sn/0.7Cu) is probably not practical due to the melting
point of 227°C. The listed Sn/Ag/In alloy is also probably not a viable candidate due to the limited availability and
cost of indium. Nevertheless, the alloys on this list are generally similar to those under evaluation by various
companies.
In board-level reliability tests using surface-mount and chip components, several of the listed alloys appeared to
perform better than the control Sn/Pb eutectic due apparently to higher mechanical strength and/or ductility. The
final recommendation of NCMS was that three of the listed alloys warranted further study. Under the NCMS criteria
the Sn/Bi eutectic would be acceptable for consumer electronics, and both the Sn/Ag/Bi and Sn/Ag/Cu would be
suitable for telecommunications, automotive, and aerospace applications.
Individual Studies
In addition to the NCMS list, other alloys are being investigated or implemented by various companies in Japan and
Europe. Showa Denko claims to have solved the problem of using zinc-containing alloys and is producing materials
with eutectic (Sn/9Zn, 199°C melting point) and non-eutectic (Sn/8Zn/3Bi, 197°C liquidus) compositions; NEC is
reported to have adopted the Showa Denko process. Sony developed a Sn/Ag/Cu/Bi/Ge alloy with a 220°C
liquidus. Other Japanese companies are working on variations of Sn/Bi or Sn/Ag/Bi compositions. Nortel has
worked primarily with the Sn/Cu eutectic, but is evaluating variations of the Sn/Ag/Cu class. Additionally, research-
ers at Iowa State University developed and patented a series of alloys based on Sn/Ag/Cu, and Flip-Chip Technolo-
gies (FCT) developed and patented a Sn/Ag/In/Cu alloy (Sn/3.1Ag/10In/1Cu, 200°C liquidus) for direct chip attach
(DCA) applications. In Europe and the US, where the production of high-reliability equipment for
telecommunications and networking constitutes a high percentage of electronic manufacturing, there is a trend
toward the use of the Sn/Ag/Cu alloy possibly with additional alloying metals.
Evaluation Issues
Evaluation of many of these new solder alloys is difficult because reliable information about the mechanical
properties and phase constituents of these materials is lacking. Mechanical properties of many of these materials
remain to be determined. Construction of phase diagrams for materials with the addition of third or fourth
constituents is practically impossible and can only be done via thermodynamic modeling methods; construction of
phase diagrams for binary alloys has proven difficult enough. Sn/Bi-based alloys exhibit a specific example of the
subtleties of phase structures. When these alloys are used with components that still have Pb-bearing contacts a
Sn/Pb/Bi eutectic phase (96°C melting point) can be formed. This phase would melt at any temperature above 96°C
causing a solder joint to become pasty and the mechanical strength of such solder joints could be severely
degraded. At least one automotive manufacturer has stated that they will not use any solder containing bismuth due
to this phenomenon,
Most discussions about solder replacement have focused on the external contacts on packages and the means for
connecting packages to boards. However, Pb-bearing solders are essential materials for flip-chip assembly
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| RES-NETWORK | Interface IC |
| RES060L03 | TRANSISTOR | MOSFET | MATCHED PAIR | N-CHANNEL | 30V V(BR)DSS | 6A I(D) | SO |
| RES070N03 | TRANSISTOR | MOSFET | N-CHANNEL | 30V V(BR)DSS | 7A I(D) | SO |
| RES100N03 | TRANSISTOR | MOSFET | N-CHANNEL | 30V V(BR)DSS | 10A I(D) | SO |
| RES5-F03 | FILTER CHASSIS OHNE IEC EINGANG 3A |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| REPORTER 8.5 PROFESSIONAL | 制造商:Flir Systems 功能描述: |
| REPOT01-10 | 制造商:RECOM Power Inc 功能描述: 制造商:RECOM Power Inc 功能描述:10A POTENTIOMETER |
| RE-PRO/09 | 制造商:BM POLYCO 功能描述:ELECTRICIANS LEATHER PROTECTOR 09 |
| RE-PRO/10 | 制造商:BM POLYCO 功能描述:ELECTRICIANS LEATHER PROTECTOR 10 |
| REPV0011A-M | 制造商:Panasonic Industrial Company 功能描述:PC BOARD |
發(fā)布緊急采購，3分鐘左右您將得到回復。