Most popular lead-free RoHS FAQ

2022-08-07
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Lead free/rohs FAQs

lead free questions

1 Ask Maxim what is the definition of lead-free

answer: lead free means that there is no lead in packaging or product manufacturing (the chemical symbol is Pb). In IC packages, Pb is common in external pin polishing or electroplating. For wafer level packages (UCSP and flip chip), Pb appears on solder balls

2. What is the lead-free material used by Dallas semiconductor/maxim integrated products

answer: 100% matte tin is used for external pin plating. A few package types contain other RoHS compliant electroplating and polishing materials, such as nickel palladium. UCSP and flip chip contain lead, but the pins of these packages are RoHS compliant. We are still developing lead-free solutions for UCSP and flip chip

3. What is the lead-free reflow soldering temperature specified by Dallas semiconductor/maximum integrated products

answer: our products meet JEDEC J-STD-020C standard:

4 Q. will Dallas semiconductor/maximum integrated products continue to provide lead-containing and lead-free products with micro DC servo motor as the power source for the belt pulling machine

yes, some customers still need to buy lead-containing products. Dallas semiconductor/maximum integrated products will continue to provide lead-containing and lead-free products

5. Q: if a model is certified as a lead-free product, does it mean that we get a lead-free product

no, it only means that we can provide the lead-free version of this model. Users who purchase lead-free products must apply to the business department of Dallas semiconductor/maxim integrated products for approval

6. Are you still unable to provide lead-free products for some models

answer: restricted by technical factors, some packaging types have not passed lead-free identification. For example: ball grid array (BGA) and flip chip. The BGA of Dallas semiconductor/maxim integrated products is easy to dissolve, and the BGA of most Dallas semiconductor/maxim integrated products is packaged as 63%sn/37%pb. However, we do have some 10mm wafer level ball grid array (csbga) packages that are sn/ag/cu and lead-free

7. Will the cost of lead-free products increase/decrease

answer: there is no obvious difference in price between lead-containing products and lead-free products

8. Is it possible to obtain lead-free products without lead-free certification

answer: if users need to provide packaging types that have not passed lead-free certification, they must submit an application to Dallas semiconductor/maxim integrated products business division

9. How long does lead-free packaging take

answer: it takes 4 weeks for sampling assembly and testing, and 10 weeks for QA reliability testing

10. What is the reflow temperature of lead-free package

answer: for all SMD (surface mount devices), the peak temperature of reflow soldering is 260 ° C

11. Where can I get the reflow soldering temperature curve of Dallas semiconductor/maximum integrated products

a curve can be obtained here:

construction reflow profile 3: required peak temperature = 235 (+5/-0) deg. c

12 What is the recommended lead-free reflow temperature curve for PC board reflow soldering

answer: the test speed and height of ipc/jedec J-s additional testing machine should be selected according to the performance of the product to be tested and the lead-free reflow soldering curve in td-020 specification

13. What is the moisture sensitivity level (MSL) of the lead-free package

please refer to the lead-free report page of Emmi station

14. Q. for lead-free products, what solder can be used to withstand the maximum 260 ° C reflow temperature of the circuit board

answer: at or below 260 ° C, the main lead-free solders that can be used are:

note: only several commonly used solders in the industry are listed here. Dallas semiconductor/maximum integrated products does not make any recommendations for the use of these solders, nor does it guarantee their performance in use

15. What lead-containing products have been transformed into lead-free products

answer: many package types have passed the certification as lead-free products, and other packages are being identified. The models of Dallas semiconductor/maxim integrated products can be identified according to their identification status. If a model has passed the lead-free identification, the Dallas semiconductor/maxim integrated products business department will make a production decision and provide lead-free packaging according to the user's requirements. For information on lead-free packaging, please refer to the lead-free report page

lead free marking

1 What is the lead-free model mark of Dallas semiconductor/maximum integrated products

answer: for lead-free models, a "+" sign is added after the full name of Dallas semiconductor/maximum integrated products

for example:

max1234eui+

max4567cut+t

max4556aesa+

2 How to identify lead-free products from their appearance or logo

answer: all lead-free products have a "+" symbol on the top of the package, which is located near the first pin or groove

3. How to mark or label RoHS compliant lead-free devices

answer: if the model has

RoHS

1. Ask whether the lead-free products of Dallas semiconductor/maximum integrated products comply with RoHS and EEC regulations

yes

rohs substances:

RoHS restricted substances include: lead, cadmium, hexavalent chromium, mercury, PBB, PBDE

possible RoHS substances in the final product: lead

RoHS substances that may be contained in packaging materials: cadmium

composition and material composition of plastic packaging:

composition of plastic packaging: lead frame, chip bonding material, bonding line, molding compound, surface polishing material, silicon wafer

material components of plastic packaging: copper, iron, zinc, phosphorus, nickel, magnesium, gold, silver, antimony trioxide, bromine, tin, lead and silicon

csp package composition and material composition:

csp package composition: silicon wafer, chip coating, UBM (metal layer), solder ball

csp packaging material composition: silicon wafer, resin, aluminum, nickel (V), copper, tin and lead

ISO 14001

1. Ask whether Dallas semiconductor/maxim integrated products are ISO 14001 certified

answer: all Maxim manufacturing, assembly and testing plants have completed ISO 14001 registration, except for Maxim Fab in San Antonio and Texas. The registration date of San Antonio Fab will be postponed until the production scale meets the requirements. The registration time has not been determined yet

frequently asked questions

1 For lead-free products, which solder can be used to withstand the maximum circuit board reflow temperature of 260 ° C

when the temperature is 260 ° C or below, the main lead-free solders are:

sn/ag4.0/cu 5 217° C (° C)

Sn/Ag2.5/Cu. 8/Sb. 5 216° C (° C)

Sn/Ag3.5 221° C (°C)

Sn/Cu. 75227 ° C (° C)

sn/bi3.0/ag3.0 213 ° C (° C)

note:

only several commonly used solders in the industry are listed here. Dallas semiconductor/maximum integrated products does not make any recommendations for the use of these solders, nor does it guarantee their performance in use

2. Can lead-free and lead-containing products be mixed in PCB reflow soldering? In this case, the performance of the interface will affect the overall performance of the composite. What is the reflow temperature

answer: the lead-free model of Dallas semiconductor/maxim integrated products can be mixed with the lead-containing model, and reflow soldering can be carried out with qualified flux under low temperature (240 ° C) and appropriate reflow conditions. However, Dallas semiconductor/maximum integrated products cannot guarantee a higher reflux temperature (above 240 ° C). Some data show that when lead-containing and lead-free products are mixed, the data reliability defined in the lower solder joint is 33% lower than that of the dissolved solder joint

3. What is the solder used by most SMT (surface mount technology) manufacturers for reflow soldering of PC boards

answer: at present, soluble solder sn63/pb37 is generally used for reflow soldering of PC boards. This solder also meets the requirements for matte tin plated pins

4. What is the melting point of solder alloy and its pure substance

5. What electroplating materials can be used for 100% matte tin

answer: for the high-speed automatic electroplating production line, the electrolyte based on MSA is the most commonly used. Many suppliers such as fidelity, englehardt, learonal, isihara, Schlotter and other professional manufacturers or local suppliers can provide this product

for manual/barrel electroplating production lines, sulfuric acid based electrolyte is commonly used. Most professional manufacturers or local suppliers can provide this product, and the price is very cheap

6. Ask whether Dallas semiconductor/maxim integrated products' products plan to eliminate halogen substances from casting compounds

answer: our "green molding material" is the only molding material without bromine. In addition to green molding materials, other molding materials contain bromine and antimony. Our "non green" molding materials contain "bromine" as a flame retardant. Bromine does not meet the definition of PBB (polybrominated biphenyls) or PBDE (polybrominated diphenyl ethers)

calculation

1 How to calculate the parts per million content of chemical components

divide the weight of the selected element (such as lead) by the unit weight, and multiply the result by 1000000. For example, if the content of lead in a certain model is 0.000375 g and the unit weight is 0.1473 g, then ppm = 0.000375/1473 x 1,000,000 = 2546 ppm。

2. How to calculate the percentage content of chemical composition

divide the weight of the selected element (such as lead) by the unit weight. For example, if the content of lead in a certain model is 0.00375g and the unit weight is 0.1473g, then% = 0.000375/0.1473 = 0.002546 x 100 = 0.2546%

humidity sensitivity grade msl

1 What is the moisture sensitivity level (MSL) of the lead-free package

please refer to the lead-free report of Emmi station

2. What is the humidity sensitivity level of lead containing packages

please refer to the humidity sensitivity level page of Emmi station

tin whisker

1 Have you ever tested tin whiskers? Describe the test conditions

answer: during assembly, tin whiskers shall be tested during packaging and identification. The test process is:

the storage time shall be extended for 500 hours and 1000 hours at 85 ° c/85% RH

store it below 50 to 55 ° C every 1, 3, 6 and 12 months

2. What is the acceptable standard for tin whiskers? What method is used to identify tin whiskers

answer: whiskers lower than 50 μ m in any direction are considered acceptable and need to be viewed with a 30x magnifying glass. There is no jedec/ipc standard for tin whisker testing, inspection and acceptance criteria

3. What is the routine monitoring and installation process control suitable for tin whiskers

answer: during installation, tin whiskers are monitored in the following ways:

visual observation is carried out under 30 times magnification, 6 times per shift, and the number of samples is 125

analyze the tin, acid and organic matter contents in the electroplating bath once a day

certification and testing

1 Why is it necessary to identify the packaging and installation technology of Dallas semiconductor/maxim integrated products' 100% matte tin plating

in high temperature reflow soldering environment (240

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