Abstract:
A socket base adaptable to a load board for testing semiconductor devices is disclosed. The socket base includes a first fixing element having coupling plates, a probe element, and a second fixing element, which are detachable and combinable. Accordingly, the procedure for replacing the probe element is simplified, time is reduced, and efficiency is increased.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention generally relates to a socket base adaptable for a load board, and more particularly to a detachable and combinable socket base for testing semiconductor devices.  
       DESCRIPTION OF THE PRIOR ART  
       [0002]     The advancement of the integrated circuits manufacturing technique brings abundant electronic products to our modern life. In addition to attaining more compact electronic products, diverse integrated circuits are simultaneously applied into a single product to obtain more functions. In order to accomplish this goal, the quality of each integrated circuit is predominantly important.  
         [0003]     The manufacture of the integrated circuits passes through a series of strictly controlled steps. The circuit is firstly designed and applied to the manufacture of wafers, followed by cutting each manufactured wafer into chips. The chips are packaged and then tested to their functionality and reliability. The test is a critical step in which malfunctioned or defective chips/integrated circuits are screened out.  
         [0004]     A probe element or prober is utilized in test equipment to contact the devices under test. One of the difficulties concerning the probe element in the conventional test equipment is the complex or time-consuming procedure to install or replace the probe element.  
         [0005]      FIG. 1A  shows conventional test equipment for testing ball grid array (BGA) integrated circuits. A robot arm  104  of a manipulator  102  lifts a test head  106  towards test apparatus  100 . A load board  108  and a socket base  110  are positioned between the test head  106  and the test apparatus  100 . The test apparatus  100 , the socket base  110 , and the load board  108  are secured together, for example, by screws before performing a test on semiconductor devices.  
         [0006]      FIG. 1B  shows a sectional view of the socket base  110  and the load board  108 . The pick tool  114  of the test apparatus  100  picks up a semiconductor device  118  by using a vacuum head  116 . The pick tool  114  secures and aligns to the socket base  110  by the guide pins  110   a . The solder balls  118   a  of the semiconductor device  118  are contacted by a probe element  112 , such as a surface mount matrix (SMM), which is further connected to the load board  108 .  
         [0007]      FIG. 1C  shows a perspective view of the load board  108 , the socket base  110 , and the SMM  112  therebetween. The guide pins  110   a  are used for alignment with the test apparatus, and the guide pins  110   b  are used for alignment with the device under test. As shown in  FIG. 1D , the test apparatus  100  is secured to the test head  106  by screws while performing the test. The socket base  110  could not easily be replaced without firstly separating the test apparatus  100  and the test head  106  whenever the SMM  112  becomes unclean.  
         [0008]     Specifically, the screws are firstly loosened, and the test head  106  is lowered by the manipulator  102 . Thereafter, the socket base  110  is removed from the load board  108 , followed by cleaning the SMM  112 . The SMM  112 , the socket base  110 , and the load board  108  are assembled in reverse steps.  
         [0009]     For the reason that conventional replacement procedure is complex and time-consuming, a need has arisen to propose a new socket base that improves the efficiency of replacing the probe element.  
       SUMMARY OF THE INVENTION  
       [0010]     In view of the foregoing, it is an object of the present invention to provide a detachable and combinable socket base to simplify the replacement procedure of the probe element.  
         [0011]     According to the object, the present invention provides a socket base adaptable to a load board for testing semiconductor devices. The socket base includes a first fixing element having an opening, first guide structures, and coupling plates; a second fixing element having first coupling structures, second guide structures; and a probe element having fixing pin holes. The first fixing element and the second fixing element are detachable and combinable by using the coupling plates. Accordingly, the procedure for replacing the probe element is simplified, consumed time is reduced, and efficiency is therefore increased. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIGS. 1A  to  1 D show conventional equipment for testing ball grid array (BGA) integrated circuits;  
         [0013]      FIG. 2  and  FIG. 3  schematically show the composing elements of a socket base and the resultant socket base according to one embodiment of the present invention;  
         [0014]      FIG. 4A  and  FIG. 4B  show two exemplary disconnected second fixing elements of the present invention;  
         [0015]      FIG. 5  schematically shows the composing elements of a socket base according to another embodiment of the present invention;  
         [0016]      FIG. 6A  and  FIG. 6B  show further two exemplary disconnected second fixing elements of the present invention;  
         [0017]      FIG. 7A  and  FIG. 7B  show two exemplary disconnected first fixing elements of the present invention; and  
         [0018]      FIG. 8A  and  FIG. 8B  show two examples of the first guide structure without using guide pins. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]     The detailed description of the present invention will be discussed in the following embodiments, which are not intended to limit the scope of the present invention, but can be adapted for other applications. While drawings are illustrated in details, it is appreciated that the quantity of the disclosed components may be greater or less than that disclosed, except expressly restricting the amount of the components.  
         [0020]      FIG. 2  schematically shows the composing elements of a socket base according to one embodiment of the present invention. A first fixing element  230  has an opening in the middle thereof, two first guide pins  232  acting as the first guide structures, and a coupling plate  234 . A second fixing element  210  is used to secure a probe element  220 , which is a surface mount matrix (SMM)  220  in this embodiment. On a first side (that is, the top side in the figure) of the second fixing element  210  are some second guide pins  212  acting as the second guide structures, and some first coupling holes  214  therethrough acting as the first coupling structures. On a second side (that is, the bottom side in the figure) of the second fixing element  210  are some fixing pins  216 . The SMM  220  has some fixing pin holes  222  corresponding with the fixing pins  216 . The coupling plate  234  of the first fixing element  230  has some second coupling holes  236  acting as the second coupling structures, which are aligned with the first coupling holes  214 , so that the second fixing element  210  could be secured to the first fixing element  230 . The first fixing element  230  also has some third coupling holes  238  which are used to secure the first fixing element  230  to a load board such as that designated as  108  shown in the previous drawings. It is appreciated that the first fixing element  230  could be configured in a shape other than that shown in the figure, and the number of the first guide pins  232  could be only one instead of two as shown.  
         [0021]     The pin holes  222  receive the fixing pins  216  of the second fixing element  210 . Thereafter, the combined second fixing element  210  and probe element  220  is embedded in the opening of the first fixing element  230  and rests on the coupling plate  234 . The three composing elements as shown are further secured by placing screws through the first coupling holes  214  and the corresponding second coupling holes  236 , thereby resulting in the socket base adapted for a load board such as that shown in  FIG. 3 . Whenever the replacement of the SMM  220  is required, the screws are firstly loosened and the second fixing element  210  is then removed to reveal the SMM  220 . This replacement procedure becomes substantially easier and faster compared to the conventional one.  
         [0022]     The first guide pins  232  on the first fixing element  230  are used for alignment with respect to test apparatus. The coupling plate  234  is extended along the peripheral of the opening, and has some (three in this example) second coupling holes  236 , which are respectively corresponding to the first coupling holes  214 . The third coupling holes  238  beside the first guide pin  232  are used to be secured to the load board (such as the load board  108  shown in  FIGS. 1A-1C ) by screws.  
         [0023]     The second guide pins  212  on the second fixing element  210  are used for guiding or aligning a device under test. It is appreciated that the number of the second guide pins  212  is not limited to two, and the second guide pins  212  are preferably opposite to each other. Similarly, the number of the first coupling holes  214  is not limited to six, and the first coupling holes  214  are configured into two groups, which are preferably opposite to each other. Also, the number of the fixing pins  216  is not limited to two, and the fixing pins  216  are preferably opposite to each other.  
         [0024]     The second fixing element  210  shown in  FIGS. 2 and 3  has a close and connected shape, while in other embodiment, a disjoined second fixing element  210  could be used instead.  FIG. 4A  shows a disconnected second fixing element  212 , which includes two U-shape parts  210   a  and  210   b . Each part has three first coupling holes  214  and a fixing pin  216 . The two second guide pins  212  could be located on one part  210   b  or could be respectively located on the two parts  210   a  and  210   b .  FIG. 4B  shows another disconnected second fixing element  212 , which includes two L-shape parts  210   c  and  210   d . Each part has three first coupling holes  214 , one fixing pin  216 , and one second guide pin  212 .  
         [0025]      FIG. 5  schematically shows the composing elements of a socket base according to another embodiment of the present invention. Compared to  FIG. 2 , a disconnected second fixing element  210  including two parts is used, and this second fixing element  210  has no second guide pins thereon. Each part has some first coupling holes  214  and a fixing pin  216 . The first fixing element  230  has some first guide pins  232  and the coupling plate  234 , and further has the second guide pins  212 . Besides, the coupling plate  234  has some second coupling holes  236 , and the first fixing element  230  has some third coupling holes  238 .  
         [0026]     It is appreciated that the number of the first guide pins  232  and the second guide pins  212  is not respectively limited to two. The first guide pins  232  are preferably opposite to each other, and the second guide pins  212  are also preferably opposite to each other. Accordingly, these guide pins  232  and  212  are configured in a cross pattern.  
         [0027]     In addition to the second fixing element  210  having two U-shape parts demonstrated in  FIG. 5 , other second fixing element such as that shown in  FIG. 6A  or  FIG. 6B  could also be used instead. The second fixing element of  FIG. 6A  has two bar-shape parts  211   c  and  211   d , and the second fixing element of  FIG. 6B  has two L-shape parts  211   e  and  211   f.    
         [0028]     Moreover, a first fixing element having disconnected configuration could also be used. For example, the first fixing element of  FIG. 7A  has two U-shape parts  230   a  and  230   b , and the first fixing element of  FIG. 7B  has two L-shape parts  230   c  and  230   d.    
         [0029]     The first guide pins  232  as demonstrated in the previous drawings could be equivalently replaced by other means, such as the indentures  232   a  in  FIG. 8A , or the protrusion  232   b  or the cave  232   c.    
         [0030]     Although specific embodiments have been illustrated and described, it will be appreciated by those skilled in the art that various modifications may be made without departing from the scope of the present invention, which is intended to be limited solely by the appended claims.