- 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)： | 10/16頁 |
| 文件大?。?/td> | 188K |
| 代理商： | REPORT |
-
6
-
Table 1: NCMS SOLDER SELECTION CRITERIA
Property
Definition
Limits
Liquidus
Temperature
Pasty Range
Temperature at which solder alloy is completely
molten.
Temperature difference between solidus and
liquidus temperatures. Represents the temperature
range where the alloy is part solid and part liquid.
A wetting balance test assesses the force resulting
when a copper wire is wetted by molten solder. A
large force indicates a good wetting, as does a short
time to attain a wetting force of zero, and a short
time to attain the two-thirds of the maximum
wetting force.
Assesses the coverage of the solder on Cu after a
typical DIP test.
Assesses the amount of oxide formed in air on the
surface of molten solder after a fixed time at
soldering temperature.
Cycles-to-failure for a given percent failed based
on a specific solder joint/board configuration, as
compared to the eutectic Sn/Pb.
Differences in thermal expansion behavior between
alloys might create differences in thermal stresses.
Stress required at room temperature to cause failure
in 10,000 minutes.
Total percent elongation of material under uniaxial
tension at room temperature.
< 225 °C
< 30 °C
Wettability
Fmax > 300 μN
t0 < 0.6 s
t2/3 < 1 s
Area of Coverage
> 85%
Drossing
Qualitative scale
Thermomechanical
Fatigue (TMF-1)
> 75%
Coeff. of Thermal
Expansion (CTE)
Creep
< 29 ppm/°C
> 500 psi
Elongation
> 10%
Alternatives to Pb in Solders
In all the discussions about elimination of Pb in electronic products, the principal question is what will be the
replacement. The usage of Sn/Pb solders dates back some 6000 years. Sn/Pb solders have been the primary
interconnection material in the electronics industry for the last 100 years. One of the great successes of the industry
has been that for joining technology the same material is used in very similar ways for almost all applications. The
large body of knowledge that has been developed regarding the properties and behavior of Sn/Pb solders would
become irrelevant if the alloy were significantly changed.
Manufacturers that have begun programs to develop Pb-free assembly processes have until recently worked
independently, and as a result a variety of alternative solder alloys have been developed. Many of these alloys are
the subjects of issued patents or pending applications. While sorting out the claims of intellectual property is not an
insurmountable obstacle to the adoption of an alloy, it will be an additional factor in the selection process.
Pb Alternatives
The number of elements that can be substituted for Pb in solders is limited. A number of metals with desirable
properties are either in limited supply (germanium, Ge) or of equal or greater toxicity than Pb itself (antimony and
cadmium). The short list of metals includes the following:
Tin (Sn): readily available, very low toxicity, easily workable, 232°C melting point;
Silver (Ag): limited availability, expensive, low human toxicity but potentially harmful to aquatic animals and
plants, oxide is conductive, easily workable, 962°C melting point;
Copper (Cu): very abundant, inexpensive, very low toxicity, easily workable, 1084°C melting point;
Bismuth (Bi): readily available, a byproduct of Pb smelting, low toxicity, low ductility and difficult to work,
272°C melting point;
Zinc (Zn): readily available, inexpensive, low toxicity, easily oxidized, 420°C melting point;
Indium (In): limited availability, low or unknown toxicity, very ductile, 157°C melting point.
It is generally assumed that tin will form the basis metal for any solder replacement alloy since the other possibili-
ties (bismuth and indium) are not sufficiently plentiful. Tin forms eutectic alloys with all of the above metals with
melting points in the range of 118°C (Sn/In) to 227°C (Sn/Cu). With additions of third, fourth, or fifth metal compo-
nents to the alloys, a very wide selection of alloys with melting or liquidus points within the 118
227°C range
(whether or not of eutectic composition) is possible.
Comparative Studies
The National Center for Manu-
facturing Sciences (NCMS) in the US
and the Brite-IDEALS project in
Europe
independently
extensive evaluations of solder alloys
based on the above metals, with and
without additional alloying metals. The
most extensive compilation of data on
solder materials is that published by
the NCMS in 1998. This consortium of
11 US manufacturers and research
organizations evaluated 79 solder
alloys based on toxicology, econom-
ics, and material properties. This
evaluation resulted in a short list of
alloys
that
were
evaluated for manufacturability and
reliability.
undertook
subsequently
Table 1 shows the primary character-
istics that NCMS used to select
candidate alloys. The consortium was
primarily looking for alloys that
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(fù)。