Distinguishing the real from the fake: A guide to chip procurement
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Some time ago, a fan told us that he couldn't debug a circuit no matter what, and suspected that he bought a fake chip. Today we will share an article on how to judge whether your chip is genuine. The following content is compiled from the Internet, and the copyright belongs to the original author. If there is any copyright issue, please contact us in time.
There are so many IC chips on the market, and if you don't pay attention to the differences, it is sometimes difficult to tell the difference between the various materials, whether they are real or fake, brand new or refurbished. Let a senior IC buyer teach you how to distinguish between original and new chips.
How fake chips are produced
There are hundreds or thousands of chips on a wafer. After the wafer is produced, it must be tested and the bad ones will be marked. The wafers that pass the test are cut and packaged. After packaging, they are the chips with pins we see. The chips marked as bad during the packaging stage will also be discarded. The wafers that fail the test are recycled by the manufacturer who bought the bare chips, cut and bonded by themselves, but the chips marked as bad will also be discarded.
Normally, the regular testing process is time-consuming and costly, so some wafer fabs will sell untested wafers to manufacturers who need bare chips and let the latter test them themselves. However, the latter usually do not have good testing equipment and reduce the number of test items to save money, resulting in some chips that would not pass the test in the semiconductor factory being used in the final product, causing unstable product quality.
Some people took advantage of these loopholes and developed professional counterfeiting companies, making a lot of money and causing some small and medium-sized companies to lose all their profits. It is undeniable that counterfeit components have become a cancer in the supply chain.
The appearance and size of the real and fake chips are almost the same
In recent years, many contractors have stopped adding new suppliers once they have established a list of authorized suppliers. However, when OEMs, OCMs, and authorized distributors are unable to provide parts, procurement personnel face few options. They can not purchase components, slow down production, or even stop production; or purchase through suppliers that have not been audited by their own organizations or have not been evaluated by any authorized third party. As a result, independent distributors, agents, and traders may provide them with original, new, refurbished, and used components.
Almost everyone in Huaqiangbei knows that some people have been purchasing electrical waste (commonly known as electronic waste) from abroad for a long time, and after bringing them back, they dismantle, sort, organize, refurbish, package, and then sell them in the electronics market in an all-in-one operation.
Workers are sorting out electronic waste
There are many forms of fraud
Primary counterfeiters are refurbishers , with a typical example being a place in Guangdong. They refurbish old chips (usually disassembled chips), and even if the pins are crooked, they can be refurbished to look like new ones, and then they are made into tubes and labeled.
A more advanced level of counterfeiting is to polish the products, turning them into more valuable ones with similar functions and sizes, and then re-labeling them with logos. Thus, commercial grade becomes industrial grade, industrial grade becomes military grade, military grade becomes 883 grade, low rate becomes high rate, low frequency becomes high frequency, and so on.
Thanks to the increasingly low prices of small laser marking machines, it is easy to use laser marking on refurbished ICs. Some traders will polish it themselves, while others will entrust it to a professional "counterfeiting assembly line" for polishing .
There is another type of counterfeiting that is so extreme that I personally suspect that a packaging factory is directly involved. This is not as simple as polishing off the logo, but directly turning dies of different sizes into another package.
The last type of counterfeiting seems to be close to laundering when it is carried to the extreme. For example, sometimes when you go to Huaqiangbei to buy an MCU, the other party will ask you whether you want the original one or the Taiwan version. There are two types of Taiwan versions: one is a direct counterfeit product, and the other may be made in Taiwan and has been tested and authorized by the original manufacturer, but may be a little short of some indicators. This type of product cannot be considered a fake.
So many people buy chips in Huaqiangbei
Generally, the focus of system manufacturers' incoming material inspection is to check the supply, labels, etc., and the ability to distinguish fake chips is really not enough. If you really want to test the performance of the chip, you may need a professional fixture from the original manufacturer.
In addition, the materials department and the R&D department are usually managed separately. Under normal circumstances, engineers may find problems with samples during the debugging process, but after the design is completed, they will not be tested again in the batch stage.
In addition, the level of counterfeiting is so high now that even the engineers of the original factory said that in many cases, it is impossible to distinguish the appearance with the naked eye. Experienced original engineers may be able to see the weirdness through familiar packaging methods, barcodes, etc., but to truly determine whether it is a fake chip, they still have to rely on advanced laboratory instruments.
The chips we buy mainly include the following:
1. Original factory packaging
Products with original packaging.
If you order from the market, you still need to pay attention. Common problems include:
1. Domestic packaged goods are counterfeit: It is difficult to identify and can only be distinguished by comparison. There are still some differences in the outer box, label and packaging.
2. Fake original packaging: Compare the label to see if it is different from the original label, and the batch number on the label should be consistent with the batch number on the chip.
The original packaging is very regular, and some are wrapped in anti-static bags, but not all manufacturers' products have anti-static bags.
If it is an unopened anti-static package, the tube or disk inside should be very clean after opening it. If there is plastic foam or shock-proof plastic bag, these accessories from foreign manufacturers are difficult to imitate in China, and the difference can be seen by comparison.
Take out several chips from a tube or tray and put them side by side. The original product's typing content is definitely the same, the typing, positioning holes, and foot positions are relatively neat, and the content in the positioning holes is also consistent. Of course, it is not ruled out that some manufacturers do not fix the positioning holes and typing positions, such as AVAGO.
2. Original
The original packaging has been opened or is no longer available, but it is still authentic product from the original manufacturer. Many products on the electronics market today are of this type. It is understandable to classify such products as authentic, but strictly speaking, they are considered new loose goods .
3. Scattered New
According to the market situation, scattered new stocks can be divided into the following categories:
1. The real meaning of scattered new
(1) The customer demand is less than a whole package. Driven by price, the supplier disassembles the original whole package and sells a part of the chips at a high price, while the remaining part is not in the original package.
(2) Suppliers unpack the goods for transportation purposes. For example, when the original goods from Hong Kong are shipped to Shenzhen and other places, in order to reduce customs duties, the original packaging is unpacked and the goods are brought in by multiple people.
(3) Brand-new goods with old years: Most of these goods have been stored for a long time and have poor appearance, so they can only be sold as new goods.
(4) Some of the products come from packaging factories: IC design companies often do not have their own wafer manufacturing and packaging factories. When a large number of wafers are sent to packaging factories for packaging, the IC design company may not be able to collect all the packaged wafers due to funding issues. In this case, the packaging factory will sell the products themselves, because they do not need to put their own labels on them and will not do packaging to increase costs, so they will sell them in bulk.
(5) Due to management problems at the packaging plant, its employees ship out the company through irregular channels, and the films are sold by resellers and flow into the country. Because these films have not undergone the final packaging process, they have no outer packaging, but the price is more favorable, sometimes even better than the price of national agents.
(6) IC design is for a single production line and is absolutely unique. However, in actual production and sales, some manufacturers do not have such a large growth volume and demand to keep the production line producing wafers. In order to ensure the performance of the production line, the factory cannot completely abandon it. Therefore, in order to ensure the production of wafers, the manufacturer will sell them at a low price to people who specialize in such goods. Another situation is that after the packaging factory has packaged, it has exceeded a certain time limit and the manufacturer has not paid for it. The packaging factory will also sell it to the recipient at a low price.
2. Substandard chips are chips that have been discarded from the IC production line due to internal quality problems and failed to pass the design manufacturer's test. Or chips that have been discarded due to improper packaging and damage to the chip appearance.
(1) Films that come off the assembly line. These are films that are rejected during the factory inspection. These films do not necessarily have quality problems, but rather some parameters have large errors. Because manufacturers often have very high requirements for the accuracy of films, such as voltage and current, these films are picked out and become the so-called loose new ones. Because the film is fragile, our old films may cause small changes in parameter errors during the processing process. This is why sometimes the same product is used by some customers without problems, while others have problems.
(2) During the quality inspection process, because of the manual and computer inspection, the production line passes through the computer. Sometimes the film does not really have a problem, but is just stuck. The staff would rather kill a thousand by mistake than let a bad film go, so a lot of them are thrown away, and these are called loose new films.
Features: Under very high quality requirements, the reflection effect is not good, and it can only meet general needs, or there is a certain failure rate. Because it is a processed product, it has a certain price advantage. When buying, you must have a clear analysis to see what his requirements for the film are. In addition, the batch number is more mixed. It is mainly obtained from agents and distributors. This kind of goods generally do not need to be processed.
3. Fake loose new goods (i.e. refurbished goods). Many merchants in the electronics market often refer to refurbished goods as loose new goods.
Summary: There are many kinds of loose new goods on the market. The first kind of loose new goods (real loose new goods) can be trusted in terms of quality. The second kind of loose new goods (defective goods) will be different from the original goods in terms of scrap rate and stability. Since these two kinds of products are all new goods, it is very difficult to distinguish. The third kind of refurbished goods is more harmful. It may be a fake, and they look the same, but in fact, the functions are completely different. Therefore, it is best to stay away from loose new goods, unless you buy them on the basis of certain guarantees.
4. Renovation
1. The real refurbished goods are refurbished old goods. After the product is produced by the original factory, it has been used and has a certain amount of wear and tear. Its performance is different from when it was first produced by the original factory. After special processing, its appearance or performance is restored to a state close to that of the original factory.
2. Another type is that the pins are crooked due to oxidation or bumping due to long-term disuse, and the appearance of the piece is repaired by re-adjusting or plating the pins. Many old loose new products have actually undergone this kind of processing, but the market is used to defining this kind of goods as "loose new".
Summary: If it is really a refurbished old chip, the quality is definitely better than the so-called loose new one, and even better than the original one. Of course, there are some disposable chips, such as one-time program chips, which have non-erasable programs and can hardly be used again. Old loose new products may have welding problems due to oxidation or crooked feet, resulting in scrap rate and stability problems.
How to identify genuine and fake chips
1. Check whether there are traces of polishing on the chip surface
The surface of any polished chip will have fine lines or even traces of previous printing. Some chips are coated with a thin layer of paint on the surface to cover it up, making it look a bit shiny and without the texture of plastic.
Simple grinding, rough treatment
Fine polishing, re-printing, laser printing
2. Look at the printing
Most of the current chips are laser marked or printed with special chip printers. The characters are clear, not conspicuous, not blurry, and difficult to erase. Refurbished chips either have "serrated" characters due to corrosion by cleaning agents, or have blurred characters, different depths, incorrect positions, easy to erase, or too conspicuous.
In addition, the silk screen printing process has long been eliminated by major IC manufacturers, but many chip refurbishments still use the silk screen printing process due to cost reasons. This is also one of the criteria for judgment. The silk screen printed words will be slightly higher than the surface of the chip, and you can feel slight unevenness or astringency by touching it.
However, it should be noted that due to the recent sharp drop in the price of small laser marking machines, more and more refurbished ICs are using laser marking. Some chips will also use this method to change the wording or simply re-mark to "improve" the grade of the chip. This requires special attention, and the distinction method is more difficult, requiring "eagle eyes and golden eyes".
The main method is to look at the overall coordination. If the handwriting does not match the background or the age of the pins, such as if the label is too new or too clear, there is a high possibility that there is a problem. However, the chips of many small factories, especially some small IC companies in China, are born like this, which adds a lot of trouble to the identification. But this method is still very meaningful for judging the chips of mainstream manufacturers.
In addition, there are more and more cases of using laser marking machines to modify chip markings recently, especially in memory and some high-end chips. Once it is found that some letters are not aligned or the strokes are of different thicknesses in the laser printing position, it can be determined that it is a Remark.
3. Look at the pins
Any tin-plated pins that are as bright as "new" must be refurbished products. The pins of most genuine ICs should be so-called "silver powder pins", which are darker in color but uniform in quality. There should be no signs of oxidation or "flux" on the surface. In addition, the pins of plug-ins such as DIP should not have scratches. Even if there are scratches (which will only appear after repackaging), they should be neat and in the same direction, and the exposed metal should be smooth and free of oxidation.
Bright as new
"Silver powder feet"
4. Check the device production date and packaging factory number
The numbers on the genuine chip, including the numbers on the bottom of the chip, should be consistent and the production time should be consistent with the device quality. However, the numbers on the refurbished chip that has not been remarked are confusing and the production time is inconsistent. Although the numbers on the front of the remarked chip are consistent, sometimes the values are unreasonable (such as "lucky numbers") or the production date is inconsistent with the device quality. If the numbers on the bottom of the device are very confusing, it also means that the device is remarked.
5. Measure device thickness and check device edges
Many polished refurbished devices (mostly power devices) with original laser printing must be polished deeply to remove the original mark, so the overall thickness of the device will be significantly smaller than the normal size. However, it is difficult for inexperienced people to distinguish without comparison or measurement with a caliper. However, there is a workaround, which is to look at the front edge of the device. Because the plastic-encapsulated device must be "demolded" after injection molding, the edge angle of the device is rounded (R angle), but the size is not large. It is easy to grind this rounded corner into a right angle during polishing. Therefore, once the front edge of the device is a right angle, it can be judged as a polished product.
Caliper thickness measurement
In addition, another method is to see whether the merchant has a large amount of original outer packaging, including paper boxes with consistent markings inside and outside, anti-static plastic bags, etc. In actual identification, multiple methods should be used together. If there is a problem in one of them, the quality of the device can be determined.
To sum up, there are several key points to distinguish authenticity:
1. Look at the typing. If the words are retyped (white), you can use "thinner" (chemical diluent) to erase them. These are usually refurbished products, and the original products cannot be erased.
2. Look at the pin angles. The pins of the original products are very neat and in a straight line, while the pins of the refurbished ones are not neat and a little crooked.
3. Look at the positioning holes. The positioning holes of the original products are relatively consistent. The positioning holes of the refurbished ones are of different depths or have been completely polished flat. If you look closely at some of them, you can see traces of the original positioning holes.
Conclusion: It is difficult to guard against counterfeits. It is recommended that you try to purchase components from regular channels to reduce the risk of buying counterfeits.
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