Research On The Failure Mechanism And Reinforcement Technology Of An IC Chip

With the development of IC industry towards higher integration level and smaller volume,the requirements of the chips' packaging technology reliability and service life are increasing.Electro-Static discharge(ESD)is the most common cause of internal failure mode which result in overheating damage of IC,and the Wire Bonding is an important process in semiconductor packaging,which greatly affects the reliability of circuits in long term use.Through statistics,Wire Bonding failure has accounted for 30% of the whole semiconductor device packaging failure mode.Therefore,through failure analysis,and according to the failure mechanism,The reliability of packaging electronic components can be improved by reinforcing the ESD protection circuit,strictly controlling the packaging environment,improving the packaging materials and Wire Bonding process.Aiming at a processor IC chip commonly used in small electronic devices such as smartphones and tablets,this paper analyzes the failure mechanism of the two samples and evaluates the risk by selecting two samples with different failure modes in a batch of failure samples of the chip.The main research contents include using various micro-analysis tests on failure samples,analyzing their failure mechanism through test data and failure morphology,and studying the improvement and reinforcement measures according to different failure modes.In this paper,a detailed failure analysis plan is developed for the failure samples,and the failure analysis and testing of the selected two samples are carried out.One of them uses copper bonding failure samples to break the circuit during electrical performance test and finds lifted-pad by electron microscope observation,and when the bonding strength test is carried out,10 wires IMC coverage test mean value is 75.73%,and 20 bonding points are selected in the bond shear test with 16 results between 2~13g F and the mean value is 10.176 g F,so it is not passed the industry standard for shear testing(?14g F)and not passed through the IMC coverage(?85%).The EDX analysis found chlorine and its high resistance corrosion product,aluminium hydroxide(alumina),so that the sample may be corroded by air impurity contamination during encapsulation,storage or transport.Then for the failure sample to improve the reinforcement,respectively,the use of palladium copper wire and gold wire on the failure sample bonding materials to reinforce,and selected 10 leads for the IMC coverage test,the average value of palladium plated copper wires are 88.07%,bonding strength increased 16%,Gold wires are 85.38%,bonding strength increased 12%,exceeding industry standards(?85%).Bond shear testing is also far beyond the standard,so the bonding area is firm.It is found that because the thin layer palladium is covered in the outer layer of copper wire,the cladding performance of gold wire bonding by gold to aluminum pad is good,which can effectively avoid the erosion of air oxidation and external impurity elements.Finally,the bonding parameters are improved and strengthened,and some constructive suggestions are put forward for the bonding process and the improvement of packaging materials.Another failure sample of a pin in the electrical characteristics of the test contrast short circuit,through the thermal infrared positioning to the failure position,the use of electron microscopy in charge of the output of the pin3 near the presence of ESD surge,after observation of the internal profile near pin3,The ESD clamp protection device found in the output port GGPMOS a gate oxygen breakdown.Therefore,this paper makes an exploratory study on the improved reinforcement method of the failure sample,in addition to the theoretical improvement and selection of the clamping device of the ESD input and output port,so that it can start the work quickly and efficiently when the ESD impact output port,and also makes an exploratory study on the power clamp circuit,A power clamp circuit with feedback regulation is designed to improve the opening time of ESD to temporary clamping MOS,so that the large current can be fully destroyed by clamping MOS,and the internal circuit should be protected from high current for long time shock.