a reactor not shown with an electrophoretic solution 310 along with conductive particles 204 carrying negative charges as shown in fig3 f a positive electric field is applied on the gold electrode 303 and the gold electrode bumps 304 due to the attraction between the positive and negative charges the conductive particles 204 carrying negative charges migrate to the surface of the gold electrode bumps 304 under the electric field the conductive particles 204 carrying negative charges are therefore tightly coupled with the gold electrode bumps 304 whose surfaces carry positive charges and the conductive particles 204 will not drift away even after the electric field is removed as shown in fig3 g after the foregoing electrophoretic positioning and fixing procedure the electric field is removed and the chip 301 is taken out of the reactor the residual photoresist 306 and the gold electrode 303 besides those on the gold electrode bumps 304 are removed as shown in fig3 h in the last step a non conductive adhesive 307 is used to join the chip 301 and the substrate 308 together as shown in fig3 i the bumps 309 on the substrate 308 conductive particles 204 carrying negative charges and gold electrode bumps 304 jointly form the electric connection between the chip 301 and the substrate 308 the positioning and fixing procedure as illustrated in fig3 e to 3 i is not applicable to conductive particles carrying positive charges because the bonding between gold and the thiol compound 201 carrying a negative charge would be de bonded under a negative electric field causing the thiol compound 201 carrying a negative charge to.