During the printed circuit board (PCB) manufacturing, different types of testing and inspection processes are carried out. This helps ensure the quality, and functionality of the manufactured PCB, along with checking it for any defects. Thus, if at all any defects are present, they can be eliminated at the earlier stages of manufacturing. Out of the several testing and inspection techniques, one is the burn-in testing method. What is this method? How are circuit boards tested with this technique? All these questions must be popping up in your mind. The answers to this question and a detailed account of burn-in testing lie in this post. Read on to know more.
What is Burn-in Testing Exactly?
A very basic question. Here’s the answer –
Application Specific Integrated Circuits (ASIC) are a kind of specially designed ICs for specific applications – as their name suggests. Therefore, it becomes a very critical and intricate task to test these circuits on a printed circuit board. This where, the burn-in testing comes into play.
The reliability of the ASICs is checked by performing the burn-in testing technique. This method of testing is generally carried out at 125 °C (257 °F). The testing is performed when power and electrical signals are applied to these application specific ICs.
Basically, this technique is carried out with different components before they are used. In this testing method, the components are stress tested. This helps ensure the reliability of the components, as well as the PCB.
During the burn-in testing, the ICs placed on the board are subjected to immense stress. This helps in identifying the defects and failures. The boards are capable of surviving the high temperatures in the testing process. Temperatures as high as 257 °F (125 °C) are maintained in the process. Also, during the process, these boards are put in a burn-in oven. The samples to be tested are supplied with the necessary voltage. Once this stress test is done, the samples are screened. This helps ensure whether they have passed the oven testing or not.
The technique is most commonly carried out with burn-in boards. What are burn-in boards? The next section explains this.
What are Burn-in Boards?
The burn-in boards are special types of boards that are mainly used for carrying out burn-in testing. Components, such as ASICs are installed on these boards to test. Special sockets are provided on the burn-in boards for the purpose of fixing the ICs in them.
What are the Materials Used for Burn in Boards?
Burn-in boards are exposed to high temperatures during testing. Thus, high-grade materials are used in these boards. A special version of flame retardant or FR4 material (High Tg FR4) for making the board capable of handling temperatures of 125 °C. If higher temperatures are to be applied then other material is used. For temperatures as high as 250 °C, the polyimide material is used. In case, the temperature is very high in the range of 300 °C, then high grade polyimide material is the best match.
This type of testing technique is very effective and allows you to check the performance and identify defects in a PCB in real time environments. Do you want to get your PCBs tested? Consulting industry experts, like Accelerated Assemblies, who can provide you comprehensive burn-in PCB testing services, is advisable.