I continued my nexus with bonding diagrams. I was given 4 new packages to update today, SOT23, SOT343, SOT343F and SOT346 (SC59). I was able to finish all of them before lunch break. The following is the comprehensive lowdown of the packages and the corresponding amount of bonding diagrams that I had done.
After lunch, I went to the line with Miss Norham. To be more specific, we went to the back end portion of the line. While waiting for our turn to perform tests on products, she mentioned that there are currently four companies supplying lead frames to NXP Semiconductor. They are Sumitomo, Enomoto, Possehl and Jade. The test that she intended to perform was to gain cognizance of the feasibility of using Possehl lead frames for production purpose for a particular device. To put it compendiously, she will put the trimmed and formed units using current production lead frame as well as those using Possehl lead frames into NT16 machine, to garner results or summary regarding the number of functional and substandard devices.
In NXP Semiconductor, as I had mentioned earlier during previous blog entries, there are two types of machines involved at the back end process. One being the IBE, and the other being NT16 or NX16 or TDD. When NT16/NX16/TDD comes into mind, ATF machine is indispensable. ATF stands for Auto Trim and Form. For more details on the differences in terms of operations between the two types, kindly refer to my previous blog entries. For this entry, I want to elaborate on the advantage of NT16/NX16/TDD over IBE. Firstly, NT15/NX16/TDD is faster and can be used for matrix as well as bi lead frames. IBE on the other hand, can only be used for bi lead frames. In addition, another difference between the two types of machine is that one PARSET is needed for an IBE, while a number of NT16/NX16/TDD can share a same PARSET. PARSET can be deemed as the repository of the information and operations for carrying out acceptance test (AT) and final test (FT). For further information on AT and FT, please refer to the following paragraphs.
From my observation as well as from the explanations provided by Miss Norham, for NT16/NX16/TDD, trimmed and formed units will be dumped into a rotating, vibrating bowl, where the units will be subsequently fed to a linear track. Here, there are sensors to sense the presence of units. Next, the units will go through a position sensor that indicates whether the units are oriented correctly or otherwise. Those units with wrong orientation will be corrected in the rotary portion. Then, the units will undergo final test (FT) to be followed by acceptance test (AT).
Besides that, there are two tests generally performed. The first being the final test (FT), and the other being the acceptance test (AT). Both are coterminous. Nonetheless, final test entails stricter or more rigorous test limits. Final test specifications are set by us, while acceptance test vicariously mirror what our customers want. Moving on with the similarities, both tests involve copious test specifications. For instance, akelvin and fkelvin. Notice that the first letter is the only discrepancy. The letter “a” refers to acceptance test, while the letter “f” indicates final test. Those units that failed either akelvin or fkelvin are regarded as units that may have missing legs or contacts, bent legs such that the clamper part of the test machine is not able to clamp the unit legs properly. If there were to be excessive amount of failed units under akelvin or fkelvin, the clamper contacts may be filthy. Next, I encountered units failing open test. These units may be devoid of dies (dummies), wires or have edge dies. Moving on, short test reveals units that have wires short circuited. Moreover, dvth and avth tests present us with a notion that units failing these tests may have flawed die attachments. Failed units of the respective tests will be guided into designated bins where they can be collected for further tests.
Lastly, I learnt about the meanings behind the notation used in marking each unit.
4 May 2010
What I did for today were just repetition of the things I had done before. Someone please succour me away from this purgatory. It is slowing emasculating my brain power as the things I am doing are just repetitive in nature. An overview of what I had done: Wafer inspection, updating of company’s Product Master Data (PMD) and acquisition of images using high power scope. The subjects of image acquisition are die sheared lead frames. Die sheared lead frames mean that the dies that were attached to the bondpads on lead frames were pushed away in a process known as die shear to evaluate the strength of the die bonding.
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