Solution Category

VCSEL module detection

Since the first company began to manufacture VCSEL in 1996, the number of VCSEL manufacturers reached its peak in 2001. At that time, more than 30 companies were engaged in the development of VCSEL products. But immediately after 2001, with the first burst of the communication foam, the number of these companies declined sharply, and in 2007, there were less than 10 companies.

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During this decade, the total shipment volume of VCSEL modules did not exceed 15 million per year. In 2017, due to Apple’s first use of VCSEL in mobile phones, VCSEL’s shipment volume skyrocketed, and it can be predicted that VCSEL will become the largest laser in semiconductor shipments.
According to Moore’s Law, the number of semiconductor chips doubles every two years, and the rapid growth is mainly due to the increase in maturity of production and manufacturing equipment and the decrease in costs. However, according to a statistic from ITRS, although its production cost has decreased very quickly, its cost is very expensive during the testing phase.
In 2015, the production and manufacturing costs were basically on par with the testing equipment costs of semiconductors. Throughout the entire production and manufacturing chain of VCSEL, as well as the module industry chain, its testing is mainly concentrated in two stages. The first stage is wafer testing, and the second stage is module testing.

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HiPA is one of the few suppliers worldwide that can provide fully automated module detection solutions. Generally speaking, customers’ demand for VCSEL module testing is mainly focused on high-speed, full function testing, and accuracy. HiPA believes that the key to truly conducting VCSEL testing is the fixture. Fixtures involve rapid detection, and precise temperature control is also a crucial part of detection.
The VCSEL module has several specific tests, including current and voltage testing items, near-field testing, far-field testing, and time-domain response.
The current and voltage testing project is basically a necessary testing project for semiconductor lasers, and its importance lies in scanning the working current of semiconductor lasers, including VCSEL, because in this process, it is necessary to know its voltage response and light output characteristics, and then screen out the parts that do not meet the efficiency standards, have abnormal linearity, or have sudden changes in the current and voltage relationship.
During this process, a crucial indicator is temperature, as different semiconductor lasers generate significant heat on very small chip surfaces during actual operation. Accurate temperature control is crucial for the drift of laser performance indicators caused by temperature throughout the entire process.
The second test item is near field. Analyze the characteristics of the actual emitting surface of VCSEL or its focal point during operation. VCSEL is arranged in matrix form in the module. Firstly, the image of this emitting surface needs to be projected onto the imaging surface through a specially designed optical system, and then tested on the imaging surface. The design of the entire set of optical surfaces is crucial. If the projected light surface is not perpendicular, errors will occur in the data tested in the near field.
The third test item is far-field testing, which is a very important indicator for human eye safety; The fourth test is time-domain response. If TOF is used, VCSEL needs to utilize fast pulse response.
HiPA has achieved fully automatic VCSEL module testing on a single machine, and can complete one VCSEL full function test every 5 seconds.