Ultrasonic vibration type auxiliary grinding device for ultra-precision machining of wafer

Abstract

The invention belongs to the field of precision machining, and particularly discloses an ultrasonic vibration type auxiliary grinding device for ultra-precision machining of a wafer. The ultrasonic vibration type auxiliary grinding device comprises a fixing unit, a grinding unit, a vibration unit and a spindle motor, wherein the spindle motor is used for driving the fixing unit, the grinding unit and the vibration unit to rotate; the fixing unit is installed on an output shaft of the spindle motor; the grinding unit is arranged at the end, away from the spindle motor, of the fixing unit and comprises an ultrasonic grinding wheel; the ultrasonic grinding wheel is installed on a vibration transmission disc and clamped by a grinding wheel clamp; the vibration unit comprises a piezoelectric driving module and a non-contact electric energy transmission module; the non-contact electric energy transmission module is installed in the end, close to the spindle motor, of the fixing unit and is connected with the piezoelectric driving module; and the piezoelectric driving module is installed in the vibration transmission disc and used for converting an alternating current signal into a vibration signal and transmitting vibration to the vibration transmission disc, so that the ultrasonic grinding wheel generates high-frequency vibration in the radial direction while rotating. The ultrasonic vibration type auxiliary grinding device disclosed by the invention can achieve high-efficiency, high-precision and high-quality wafer grinding.

Description

technical field [0001] The invention belongs to the field of precision machining, and more specifically relates to an ultrasonic vibration-assisted grinding device for wafer ultra-precision machining. Background technique [0002] Materials such as monocrystalline silicon and silicon carbide have gradually become the preferred materials for wafer substrates due to their excellent properties such as high hardness, low density, low thermal expansion coefficient, and good chemical stability. However, due to the characteristics of high brittleness and low fracture toughness, this kind of material is a typical hard and brittle difficult-to-machine material. The removal mechanism of the plastic domain of the material is different from the plastic removal method of metal-like plastic materials dominated by dislocation movement. Scribing and edge grinding are important processes from the production of single crystal silicon to the manufacture of semiconductor chips. The traditional ...

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Problems solved by technology

For example, patent CN206998465U discloses a two-dimensional ultrasonic vibration abrasive belt grinding device for grinding hard and brittle materials, which couples the ultrasonic vibrations generated by the longitudinal ultrasonic vibration system and the transverse ultrasonic vibration system to form an elliptical ultrasonic vibration, and A spiral grinding trajectory is formed on the surface of the processed workpiece through flexible abrasive belt feeding; for another example, the patent CN110653668A discloses a three-dimensional variable parameter rotating ultrasonic grinding device for hard and brittle materials for automobiles, which improves the The automation level of the processing of hard and brittle materials for vehicles; as another example, the patent CN108637802A discloses an ultrasonic assisted grinding device, which solves the problem of hard and brittle materials due to their special properties of high hardness and high brittleness, which are easily caused by conventional grinding processes. Technical problems of surface damage such as microcracks on the surface of hard and brittle materials, chipping of parts, etc.

[0004] However, none of the existing ultrasonic grinding devices can be applied to the grinding of wafers. The main reasons are as follows: 1) The grinding tool is set coaxially with the transmission shaft, and the ultrasonic vibration is along the axial direction of the transmission shaft. Ultrasonic vibration grinding. When the wafer is scribing and edging, the grinding wheel is generally perpendicular to the wafer surface, and radial ultrasonic vibration needs to be applied. The existing axial ultrasonic vibration cannot meet the requirements of wafer grinding. 2) The size of the grinding device is generally large, which cannot meet the high-speed (generally 20000rpm-30000rpm) grinding requirements of the wafer. When performing high-speed grinding, it is difficult for the large-volume grinding device to maintain dynamic balance. Poor chipping quality may even cause adverse consequences such as wafer breakage

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