The Influence Of Thermal Annealing On Cooper TSV Protrusion And Analysis Of Corresponding Internal Stress

3D integrat ion bas ed on through s ilic on via(TSV)tec hnology is bec oming the ma ins trea m o f pac kaging tec hnology whic h c an ac hie ve the high dens it y and s hortes t interc onnec tion,minimum c hip s iz e,better performa nc e and lower power cons umption.Howeve r,as the TSV fabric at ion and c ons eque nt us ing,due to the large differe nc e in coeffic ie nt of ther ma l expans ion(CT E)betwe en Cu and the s urrounding s ilic on,irre vers ib le protrus ion of Cu will be for med in the vert ic al direc tion w ith the c ons train of s urrounding s ilic on and induc e large ther ma l s tress es in the TSVs and Si lic on dur ing the proc ess of heat ing or ther ma l c yc ling,thus c aus ing many proble ms s uc h as c rac k or dela minat ion a nd da ma ge to the dielec tric laye r,pos ing a r is k o f reliability proble m to the devic e.This thes is is aim to solve the proble m by s tudying on the rules and c orresponding mec ha nis m of Cu-TSV protrus ion and the relations hip with s tress in the s truc ture.The res earc h and ma in conc lus ion of this thes is :1.Study on the inf luenc e of annea ling te mperatur e,heat ing s peed,annea ling durat ion time and mult i-annea ling to the Cu-TSV protrus ion.Find the domina nt mec ha nis m of Cu-TSV protrus ion by SEM and FIB.The res ult s hows that the protrus ion inc reas es wit h annea ling temper ature,espec ia lly after 300°C,while he at ing s peed is a lso one of the ma in para met ers for the copper protrus ion.The mec ha nis m for copper protrus ion is differe nt wit h te mperatur e and both gra in gro wth and stress are the ma in fac tors.A higher te mperat ure of anne aling after Cu plating than that of the s ubs eque nt ther ma l a nne a ling c an e liminate the protrus ion effec t.2.The dis tribut ion and evolut ion of s tress in s ilic on near Cu-TSV in the proc es s of heat treat ment(both high temperat ure and room temper ature)were s tudied.The re lat ions hip bet wee n s tress and Cu-TSV protrus ion in differ ent annea ling te mperat ure is ana lyzed.The elas tic modulus of c opper is tes ted by the na nometer indentat ion exper ime nt,whic h is fitted with trend of the s tress in s ilicon.The res ults s ho w that the res idua l s tress of Cu-TSV and its adjac ent s ilic on inc re as es wit h the annea ling te mperatur e,whic h is c ons is tent with the rule of Cu-TSV protrus ion.The axia l s tress in the Cu-TSV and its dis tribution in the vert ic al dir ec tion are the ma in f ac tors that inf luenc e the protrus ion of Cu.