Spring assembly and test socket using the same

Abstract

Spring assemblies and a test socket using the spring assemblies. The spring assemblies are used in a test socket electrically connecting lead terminals of a semiconductor chip to test terminals of a test device by contacting the lead terminals and the test terminals, and include: first springs in which a first steel wire having elasticity and conductivity is coiled in a spiral in one direction; and second springs in which a second steel wire having elasticity and conductivity is coiled in a spiral in an opposite direction to the direction in which the first springs are coiled, which have outer diameters narrower than inner diameters of the first springs, and are inserted into the first springs. Accordingly, electric resistances and inductances of two spring assemblies coiled in a spiral are reduced to improve electricity transmission characteristic. A height of a test socket is easily adjusted using spring assemblies having desired lengths. Also, since only plating is performed on the springs to form the spring assemblies, the spring assemblies are formed at a very low cost and have a wide range of applications.

1 . Spring assemblies used in a test socket electrically connecting lead terminals of a semiconductor chip to test terminals of a test device, comprising:
 first springs in which a first steel wire having elasticity and conductivity is coiled in a spiral in one direction; and   second springs in which a second steel wire having elasticity and conductivity is coiled in a spiral in an opposite direction to the direction in which the first springs are coiled and which have outer diameters narrower than inner diameters of the first spring and are inserted into the first springs.   
     
     
         2 . The spring assemblies of  claim 1 , wherein when the number of coiling of the first springs is N 1 , and the number of coiling of the second springs is N 2 , the numbers N 1  and N 2  are 0.3 ≦N 2 /N 1  ≦3.0. 
     
     
         3 . The spring assemblies of  claim 1 , wherein the first and second springs comprise plating layers comprising at least one of nickel (Ni), iron (Fe), copper (Cu), gold (Au), and silver (Ag). 
     
     
         4 . The spring assemblies of  claim 1 , wherein the first and second springs are soldered together at at least one of upper and lower parts of the first and second springs. 
     
     
         5 . A test socket comprising the spring assemblies of any one of  claims 1  through  4 , comprising:
 a housing which comprises a plurality of through-holes formed in positions corresponding to the lead terminals of the semiconductor and supports the spring assemblies inserted into the through-holes. 
 
     
     
         6 . The test socket of  claim 5 , wherein the housing comprises anti-escaping parts formed in inner surfaces of the through-holes to prevent the spring assemblies from escaping from the housing. 
     
     
         7 . The test socket of  claim 5 , further comprising a contact sheet, wherein the contact sheet comprises:
 conductive pads which respectively contact the spring assemblies; and   an insulating film which supports the conductive pads so that the conductive pads are arranged at positions corresponding to the spring assemblies.   
     
     
         8 . The test socket of  claim 7 , wherein at least one of Ni powder and diamond powder is coated on surfaces of parts of the conductive pads contacting the lead terminals or the test terminals. 
     
     
         9 . The test socket of  claim 7 , wherein the insulating film is adhered onto one of upper and lower surfaces of the housing.