2024-08-16 11:51:11

Use of SWIR Camera in Wafer Bonding Inspection

Years of practice has found that SWIR is suitable for wafer bonding inspection, and can provide fast, accurate, non-destructive inspection images. (Optical inspection is a one of the most effective way for wafer defect inspection. It uses a light source to illuminate the wafer surface, and then collects reflected light or transmitted scattered light information to determine defects.)

Before the chip is thinned, the wafer is attached to the carrier with glue, and a bond is formed between wafer and carrier. Common carrier materials include glass, sapphire and silicon carbide (SiC). If there is an unbonded area (such as a bubble) at the bonding interface between the wafer and the carrier, the incident light will be reflected multiple times on the upper and back surfaces of the unbonded area, while the light will be directly transmitted at the normal bonding area. This difference will be processed by the camera and a clear light and dark difference will appear on the display.

After the glass and sapphire carriers and wafers are bonded, if bubbles (unbonded area) appear, they can be observed by naked eyes or normal cameras. When using silicon carbide carriers, because the material itself is translucent green, visible light cannot penetrate well and observe the bubble well, but SWIR cameras can penetrate the material well. The following picture shows a bonded wafer using Gatherstar SWIR camera and matching mount:

The detection system mainly consists of four parts: light source,mount, infrared camera and computer. The structure is shown below. Wafers of different sizes have different imaging distances, which can be adjusted by changing the height of the mount and the focal length of the camera.

Gatherstar provides industrial SWIR cameras with different resolutions and frame rates. Contact us now for professional advice！

Sales Manager: Lily Liu

Mobile: 086-13359283296

Email: info@gatherstarhk.com

Xi'an Gatherstar Optoelectronic System Co.,Ltd is specialized in infrared and laser photoelectric system products and module, components and elements. we are not only confident in supplying qualified optoelectronic products to all of our customers, but also concentrating on offering continuous innovations and reliable service.