Method for directly bonding silicon slice with sapphire slice

Abstract

The invention discloses a method for directly bonding a silicon wafer and a sapphire wafer, comprising the following steps: 1) preparing a polished silicon wafer and a sapphire wafer, and etching a stress relief groove on one or both sides of the silicon wafer; 2) Carrying out plasma activation treatment on the surface with the stress relief groove on the silicon wafer, and performing plasma activation treatment on the single side of the sapphire wafer; 3) combining the plasma activation treatment surface on the silicon wafer with the The surface of the sapphire wafer that has been treated with plasma activation is pre-bonded; 4) the pre-bonded silicon wafer and the sapphire wafer are annealed, so that the silicon wafer and the sapphire wafer are completely bonded. The present invention etches the stress relief groove on the silicon chip, and under the condition of high annealing temperature, the thermal stress can be released relatively concentratedly at the stress relief groove, so that the silicon chip cracks along the stress relief groove, thereby preventing the silicon chip from being damaged. The regular fragmentation improves the bonding quality and facilitates the fabrication of electronic devices on the bonded silicon wafers.

Description

technical field [0001] The invention relates to a method for directly bonding a silicon wafer and a sapphire wafer. Background technique [0002] In MEMS (Micro-Electro-Mechanical System) processing technology, silicon wafer bonding technology is usually used. Silicon wafer and sapphire wafer bonding is one of the common silicon wafer bonding technologies. Silicon wafer and sapphire wafer bonding are completed. After that, different electronic devices (such as pressure sensors, etc.) are fabricated on the silicon wafer. In the prior art, when the silicon wafer and the sapphire wafer are directly bonded, the silicon wafer and the sapphire wafer need to be annealed. The higher the annealing temperature, the better the bonding quality between the silicon wafer and the sapphire wafer. However, due to the large gap between the linear expansion coefficients of silicon and sapphire, the thermal stress generated during the annealing process is relatively large, and the higher the a...

AI Technical Summary

Problems solved by technology

When the annealing temperature exceeds 250°C, the large enough thermal stress can easily lead to random cracking of the silicon wafer, which greatly reduces the qualified rate of bonding products

When the annealing temperature is lower than 250°C, the bonding quality is low and cannot meet the production requirements of many electronic devices.

Images