Research On Eccentric Peeling Mechanism And Coupling Control Method Of Chip

Chip peeling is a process of chip peeling from chip-adhesive-substrate,often used for chip peeling transfer.The chip size is very small,and the peeling requires high positioning accuracy.Due to the unpredictability of the deformation of the film surface,the chip positioning error is inevitable,which has a great impact on the reliability of chip peeling,and in serious cases,it will lead to the actual problems such as vertical chip and flying chip.Chip position can be corrected visually,but chip sorting requires high efficiency,and as performance improves,the conflict between reliability and efficiency becomes more obvious.In this case,how to achieve reliable eccentric peeling becomes an inevitable situation to face.This paper analyzes the peeling problem in the case of eccentric positioning of chips,reveals the influence of eccentricity on peeling,and puts forward the coupling control method.The main contents include:(1)The failure mode of bonding interface between chip and blue film is analyzed by scanning electron microscope,and the bonding peel model under eccentricity is established;The cohesive force bilinear constitutive model(CZM element)and related parameters are determined by uniaxial tensile debonding experiments of silicon wafers and blue films,and the release rate of adhesive debonding energy is calculated as 10.3567N/m.(2)The establishment of a single plunger eccentric adhesive peel mechanics model,through the mechanical analysis of chip eccentricity peeling mechanism and crack germination characteristics is analyzed,and the analysis shows that the chip size has important influence on chip peeling failure forms,when the small size of the chip,the main failure forms of capsizing,increases as the size,chip damage failure risks.Its failure form is damage,which points out the direction for improving chip peeling reliability.(3)The eccentric peeling mechanics model is set up in the process of peeling the chip’s rigidity characteristics are analyzed,and according to the requirements of safety and reliability,the bonding force is deduced and the relationship between the chip eccentric value,be established under the condition of maximum eccentric allowances and bonding force applied limits,thus peeling process control method of bonding force,and the eccentric value engineering design criteria.The CZM element and finite element model are used to simulate the chip peeling and capsizing process.The results show that appropriately increasing the coupling force can effectively improve the chip anticapsizing ability,but too much coupling force will cause chip damage,which well confirms the analytical results.The results show that this method can greatly improve the reliability and sorting efficiency of chip peeling.(4)A mechanical model of surface coupling eccentric peeling is established,and the effects of eccentric distance and coupling force on the safety peeling characteristics are analyzed.The appropriate structure form of surface coupling and the control range of maximum allowable eccentric value and coupling force are given.To establish finite element model of coupled peeling process of peeling system is simulated,the results show that the method using the local stiffness of the coupling to improve chip,chip in the process of decreasing peeling bending degree,this can significantly reduce the chip stress level in the process of peeling,and to break through the chip size limit,effectively eliminate the influence of eccentricity on the safety and reliability.(5)A surface coupling staged peeling mechanism is designed,and a staged coupling peeling process is proposed.The rationality of the new technology is proved by numerical simulation.The key parameters are optimized by simulation,and the design range is given,including the coupling surface size is 0.35～0.65 of the chip size,and the phased peel jacking height node is 0.571～0.714 of the total jacking height.To sum up,this paper analyzes the mechanism of chip eccentric peeling by using bonding peeling mechanical model and CZM finite element simulation,points out the failure forms of chip tipping and damage,and puts forward an effective coupling control method to realize the dual improvement of peeling reliability and sorting efficiency.