Introduction
The Alpha 4EA OTP Writer has been well received since its introduction. However, as the socket of 4EA OTP Writer is designed specifically for 28-pin DIP package and the Demo Board, this may not meet the need for smaller-sized or special shaped PCB boards, etc. So in many cases you may need to make a separate connecting rack to go with the PCB board for data burning. The following introduces how to make such a rack and points out some aspects that you should be aware of.
From Wafer to data burning, there are several steps:
1． Wafer cutting
2． PCB making
3． IC bonding
4． Burning rack making
1. Wafer Cutting
Find and choose a factory for wafer cutting after receiving the wafer. During the cutting procedure, pay attention to the following: 1. avoid damage. 2. clear the residue. You can check these by observing a cut dice with a microscope. To save the effort, you can ask Alpha to do this for you and receive the finished dices only.
2. PCB Manufacturing
Alpha 4EA OTP offers two standard finished products: 28-pin DIP package and the Demo board. They both have a corresponding port on 4EA OTP Writer for direct burning. If the two models cannot satisfy your need (due to improper size or other reasons), you can make your own PCBs. Remember to leave the space for the burning pins (see 4EA OTP user manual). In fact, you only need to provide the information about the pins and connection, almost any PCB manufacturer can design the layout and make the PCB for you.
The following is a figure for reference. You can design your PCB boards according to your requirement.
Figure 1:
3. IC Bonding
Once the PCBs and the dices are ready, you need to find a factory for bonding the IC. There are many bonding factories at your choice, and problems are easy to occur during this step because the processing quality and bonder parameters vary from factory to factory. Possible problems include: deflective positioning, bonding pad damage, IC unable to work normally, high current, etc. Generally, you need some instruments, say, a microscope to help identify the problems. In the above figure, the position indicated by the rectangle is where the OTP IC is encapsulated.
4. Burning Rack Making
After receiving the finished PCB boards, you can start burning the OTP IC. In case the Alpha 4EA OTP Writer cannot burn the IC on your PCB, you can connect the burning pins on the PCB to the Writer through soldering. This method is however unwise and inconvenient. It’s recommended that you make a connecting rack (which may involve some manual work) with contact pins matching the burning pins, and connect the contact pins to the Writer through a wire (refer to section 2 “PCB manufacturing” and the appendix). Note that the connecting wire should be short, otherwise the burning result may be incorrect or even fail.
Appendix 1:
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