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▲ SD Optics’ semiconductor glass substrate TGV inspection solution ‘TGV Vision Master’ inspecting a sample.

A technology has emerged that can fully inspect ‘Through Glass Via (TGV)’, which is considered the most difficult process in semiconductor glass substrate manufacturing. As the introduction of glass substrates in the semiconductor industry is promoted, solutions for commercialization are being developed one after another.

SD Optics announced on the 5th that it has developed ‘TGV Vision Master’, which can fully inspect TGVs using a 3D line scanner.

TGVs are passages that transmit electric signals by drilling holes tens of micrometers (㎛) in size into a glass substrate and filling them with metals such as copper. In order for TGVs to function properly, the size and spacing of the holes must be uniform. In particular, there must be no deviation in the diameters of the upper and lower holes to ensure reliability.

SD Optics has developed a technology to measure TGV holes in real time as a 3D shape using an optical scanner positioned vertically and diagonally on a glass substrate. The concept is to directly measure the upper and lower surfaces and inner diameter of the hole to determine whether the TGV process was performed properly. The company explained that it can precisely analyze the round shape of the hole, taper angle, and upper and lower hole position deviation, immediately identify minute deviations in the process, and manage the quality of semiconductor glass substrates through this.

▲ SD Optics inspection image. The outer diameter, inner diameter, positional accuracy, and roundness of the TGV holes

on a semiconductor glass substrate were measured (Photo = SD Optics)

This type of inspection requires an optical scanner to quickly change focus, and SD Optics utilized its patented MALS technology. With MEMS technology, the MALS lens has approximately 8,000 micro mirrors inside that control the angle of light and focus in real time. This is the technology that SD Optics also supplied to the world-class optical company Carl Zeiss Germany.

With this technology, SD Optics’ TGV Vision Master has achieved a scanning speed of 40mm per second. The inspection speed was an obstacle that prevented the full inspection of semiconductor glass substrates, but the company has made it possible to quickly inspect even 510mm x 515mm semiconductor glass substrates, making full inspection possible.

The company also explained that it can simultaneously detect defect images such as cracks or chipping on the upper, middle, and lower surfaces of the TGV hole. Such cracks are a factor that causes semiconductor glass substrates to break due to heat and pressure during the post-process. Detecting such defects at the early stage of process helps improving the manufacturing yield. A company official said, “The repeat accuracy is at the level of 0.25㎛, which is higher than the 0.3㎛ required by the industry.”

In addition, TGV Vision Master also provides an inspection function after cutting the glass substrate. The semiconductor glass substrate is cut into individual units after the Ajinomoto Build-up Film (ABF) process, an insulating film. TGV Vision Master can identify the size, thickness, substrate step, and defects of individual units after this singulation process.

SD Optics will supply new solutions to customers in cooperation with Philoptics Co, Ltd., a semiconductor glass substrate processing equipment company. Philoptics plans to manufacture a turn-key inspection equipment and supply to semiconductor glass substrate manufacturers. It has secured one customer and is currently discussing a contract with global semiconductor glass substrate manufacturers.

Mr. Kyoung Seok Jung, Vice President and Chief Strategy Officer (CSO) of SD Optics, emphasized, “This is the first comprehensive inspection system to be applied to actual semiconductor glass substrate production lines, providing higher efficiency and precision than existing individual inspection methods,” and “It will contribute to improving the quality of glass substrate processes and enhancing productivity.”

Issue Date: March 6, 2025

News URL: https://www.etnews.com/20250305000109