Alignment mark for silicon carbide device and preparation method thereof

Abstract

The present invention discloses an alignment mark for a silicon carbide device and a preparation method thereof. The preparation method comprises the steps of carrying out ion implantation on the position where an alignment mark is to be marked at the surface of a silicon substrate to form an ion implantation area, making a difference of the brightness of an ion-implantation area and a non-ion-implantation area to form the alignment mark, wherein an ion implantation area which is aligned with the alignment mark is formed at the surface of the silicon substrate, and the brightness of the ion-implantation area and the non-ion-implantation area is different. According to the preparation method, by using the alignment mark formed on a wafer by using the ion implantation, the difference of the alignment mark and a background is large enough, the identification positioning can be realized through eyes and an image recognition device, thus wrong operations can be reduced, the rework rate is reduced, doped atoms are nearly not diffused in a silicon carbide material, and the possibility of pollution is little.

Description

technical field [0001] The invention relates to the field of semiconductor processing technology for silicon carbide devices. More specifically, it relates to an alignment mark for a silicon carbide device and a preparation method thereof. Background technique [0002] As a third-generation broadband compound semiconductor material, silicon carbide has incomparable advantages over traditional silicon and gallium arsenide materials in terms of band gap, maximum field strength, doping concentration, and thermal conductivity, and is especially suitable for high-voltage, High-frequency, high-power, high-irradiation and photoelectric detection fields of certain wavelengths. At present, silicon carbide has attracted the attention of researchers in power microwave and optoelectronic devices. [0003] Compared with traditional silicon-based devices, silicon carbide devices have the advantages of simple structure, small size and high performance based on the advantages of silicon c...

AI Technical Summary

Problems solved by technology

[0008] First, the silicon carbide material itself is translucent, and the contrast between the alignment mark formed on the wafer and the background is not enough. It is difficult to identify and locate through the artificial naked eye and image recognition equipment, which easily leads to misoperation and high rework rate.

Even increasing the depth of the groove as the alignment mark, or increasing the height of the protrusion as the alignment mark cannot completely solve the problem

[0009] Second, the hardness of the silicon carbide material is relatively high, and it is difficult to etch. It takes a long time to etch the groove or protrusion as the alignment mark, and the thickness of the photoresist used as the etching mask is also relatively large, which makes the The manufacturing time of the quasi-mark is very long, the difficulty becomes greater, and the cost increases

However, due to the need for some unique long-term high-temperature processing steps during the preparation of silicon carbide devices, no metal or other non-silicon carbide substances can be left on the wafer surface during this high-temperature processing step.

Therefore, the metal layer needs to be removed after the alignment marks are formed on the wafer, which complicates the manufacturing process of silicon carbide devices and increases the possibility of contamination of the wafer or equipment

Images