IC Socket Technical Information

 

What is Test socket?

A test socket is a type of IC socket that is used to inspect the electrical characteristics of a semiconductor device to test and confirm its specifications. It can be categorized into two types: one is used for functional testing in mass production lines during the post-processing phase of semiconductor manufacturing, and the other is used for characteristic evaluation during the prototype phase of first-article products.

In contrast to the test socket, there is also the burn-in socket, which conducts accelerated testing while maintaining continuity (with power applied), whereas the test socket is used to confirm the IC function (i.e., the electrical characteristics of a semiconductor device), thereby serving a different purpose. Due to these functional differences, burn-in sockets are typically used in high-temperature environments and are often soldered to the board, making them difficult to replace. On the other hand, test sockets are utilized in the mass production process and are attached to the board via surface-mount technology (screwed in place), highlighting another difference in the mounting method.

 

Recent trends in electrical property testing of semiconductors

It is commonly understood that the electrical characteristics of semiconductors and devices are typically tested at room temperature using a test socket assembled in the post-process equipment of the semiconductor manufacturing process. However, recently, depending on the environment in which the semiconductors and devices are used and the required reliability, tests at both high and low temperatures have been introduced.

For instance, there has been an increase in cases where tests are conducted at temperatures ranging from -10°C to 105°C. There are also tri-temperature tests conducted at high, room, and low temperatures (150°C / room temperature / -40°C). It is crucial to ensure that operations at low temperatures for memory, as well as electrical characteristic tests, are performed at 90°C / room temperature / -40°C.

An important distinction to keep in mind here is between the electrical characteristic test and the burn-in test, which is performed in a high-temperature environment. While the burn-in test typically lasts several hours, the electrical characteristic test using a test socket (in mass production) generally lasts only a few seconds, even at high temperatures. In the case of characteristic evaluations, it sometimes takes 1 to 2 hours.

 

Things required for Test socket

Certainty of a function test

This is true for IC sockets in general: test sockets must also ensure that the device terminals and the socket probes maintain high and stable contact to consistently avoid resistance, even after repeated use.

Longer life and durability

In particular, test sockets used for electrical characteristic test in mass production lines are required to have a longer life and durability. The main reason for this is that mass production lines have to measure a large number of semiconductors and devices, and for example, if they have a short life, they have to be replaced frequently, resulting in a decrease in productivity.

Socket spec to meet different device requirements

Compared to burn-in sockets, which prioritize continuity in high-temperature environments, test sockets have specifications designed to support waveform measurement for devices where high-frequency characteristics are crucial, as well as specifications that accommodate current and heat generation for high-current devices. It is essential for these sockets to be capable of measuring the electrical characteristics in accordance with the specific requirements of the device.