Study Of The Silicon-based Transient Device And Its Process Realization

Transient electronics is a new electronic technology in recent years.It refers to the electronic devices or circuit with a specific function whose function or physical form can be destroyed or partially disappears.Transient electronic has a wide range of application including information security,environment-friendly,implantable and other electronic equipment.As for information security electronic equipment,current transient electronic relies on new materials and processes to achieve degradable electronic devices or circuits.However,it is difficult to achieve this technical route in traditional silicon-based integrated circuits.There are also other transient chips with corrosive chemical reagents or energetic materials.However,on the one hand they have a security risk on the other hand their manufacturing process have a big different with traditional semiconductor manufacturing process.Faced with these problems,in this paper,we made a study of a new silicon-based transient devices and its process realization by theoretical analysis,simulation calculation and experimental demonstration.The main research works are:First,due to microcracks or dislocations in single crystal silicon,its actual strength is far less than theoretical strength and has a great relationship with its actual size,surface topography and so on.We got the bending strength of silicon die with different size by three point bending test,and calculated influence of the etched trench in silicon die on stress concentration by ABAQUS.We also made some crack propagation simulation of silicon dies based on extended finite element method by ABAQUS.Then,we analyzed the existing stress introduction methods and its principle of stress-production,proved the limitation of the stress introduction by covering film on the silicon die.So we proposed a method to introduce stress by etching trenches on the surface of silicon die and filling the trenches with a thermal expansion material.Using COMSOL,we analyzed and compared the stress that introduced by the three kinds filled metals such as aluminum,zinc and copper at different temperatures,and created some stress concentration and stress superposition point to increase local stress by the method of etching V-shaped sharp corners at the edge of the trench.COMSOL's calculation shows that at 250?,when the filled metal is copper,the average introduced stress is above 300 MPa and the maximum stress in the stress concentration point can be above 1.5GPa,when the filled metal is zinc,the average introduced stress is above 500 MPa and the maximum stress can be above 2GPa.Finally,several silicon die etching schemes were designed and processed by the third party.The process of electroplating the metal copper in the deep trough was studied and we completed the process of silicon-based transient device.The device power test results show that it can produce physical cracks.