Patent Publication Number: US-2009224787-A1

Title: Probing apparatus for measuring electrical properties of integrated circuit devices on semiconductor wafer

Description:
BACKGROUND OF THE INVENTION 
     (A) Field of the Invention 
     The present invention relates to a probing apparatus for measuring electrical properties of integrated circuit devices on a semiconductor wafer, and more particularly, to a probing apparatus having a holder configured to rotate a semiconductor wafer around a probe card configured to measure electrical properties of integrated circuit devices on the semiconductor wafer. 
     (B) Description of the Related Art 
     Generally, it is necessary to measure electrical properties of integrated circuit devices at the wafer level to verify that the integrated circuit device satisfies the product specification. Integrated circuit devices with all electrical properties satisfying specifications are selected to continue through the subsequent packaging process, while other devices are discarded to avoid additional packaging cost. Another electrical property test is performed on the integrated circuit device after the packaging process is completed to identify and scrap unsatisfactory devices so as to increase product yield. In other words, the integrated circuit device undergoes several tests during the manufacturing process. Apparatus known as wafer-probing machines have been used to electrically measure electrical properties of integrated circuit devices on semiconductor wafers. In such apparatus, a probing needle is usually brought into contact with a target portion (test key) of the integrated circuit device to collect electrical information or data on one or more electrical properties of the integrated circuit device. 
     However, the conventional probing machine only allows the probing needle to contact the test key along one direction, which limits the circuit designer to position the test key only along a certain direction. If the test keys are designed to be positioned along two perpendicular directions, the semiconductor wafer must undergo two individual testing processes, which is time-consuming in cases where the test is performed at high temperature since the operator can not rotate the semiconductor wafer by hand until the temperature has cooled to room temperature, which may be time-consuming. 
     SUMMARY OF THE INVENTION 
     One aspect of the present invention provides a probing apparatus having a holder configured to rotate a semiconductor wafer around a probe card configured to measure electrical properties of integrated circuit devices on the semiconductor wafer. 
     A probing apparatus according to this aspect of the present invention comprises a wafer chuck configured to receive a semiconductor wafer having a plurality of integrated circuit devices and test keys configured to monitor the fabrication quality of the integrated circuit devices, a carrier configured to receive a probe card having a plurality of probe needles configured to contact the test keys of the semiconductor wafer to collect electrical information of the integrated circuit devices, and an angular adjusting module configured to adjust the angle between the probe card and the semiconductor wafer by rotating the semiconductor wafer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objectives and advantages of the present invention will become apparent upon reading the following description and upon reference to the accompanying drawings in which: 
         FIG. 1  to  FIG. 8  illustrate a probing apparatus according to one embodiment of the present invention; and 
         FIG. 9  to  FIG. 12  illustrate the operation of the probing apparatus according to one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  to  FIG. 8  illustrate a probing apparatus  10  according to one embodiment of the present invention. Referring to  FIG. 1  and  FIG. 2 , the probing apparatus  10  comprises a wafer chuck  12  configured to receive a semiconductor wafer  14 , a carrier  20  configured to receive a probe card  26  shown in  FIG. 4 , and an angular adjusting module  30  configured to adjust the angle between the probe card  26  and the semiconductor wafer  14  by rotating the semiconductor wafer  14 . 
     Referring to  FIG. 1  and  FIG. 2 , the angular adjusting module  30  includes a ring-shaped member  32 , a driving device  52  positioned on the ring-shaped member  32  and a plurality of braces  34  positioned on the driving device  52 . The braces  34  are configured to hold a bottom surface of the semiconductor wafer  14  by vacuum force via an opening  36  or configured to clip a peripheral of the semiconductor wafer  14 . In particular, the wafer chuck  12  may include a heating member and a cooling member configured to adjust the temperature of the semiconductor wafer  14  positioned on the wafer chuck  12  by vacuum force. 
     Referring to  FIG. 1  and  FIG. 2 , the probing apparatus  10  may include an elevator  50  configured to move the semiconductor wafer  14  vertically. For example, the wafer chuck  12  is disposed on the elevator  50 , and the elevator  50  is configured to move the wafer chuck  12  vertically such that the semiconductor wafer  14  on the wafer chuck  12  can be moved vertically. Furthermore, the elevator  50  may be optionally configured to move the angular adjusting module  30  vertically such that the semiconductor wafer  14  can be lifted from the wafer chuck  12  vertically by the braces  34 . 
     Referring to  FIG. 3 . The semiconductor wafer  14  includes a plurality of integrated circuit devices  16  such as main dies and a plurality of test keys  18  configured to monitor the fabrication quality of the integrated circuit devices  16 . The test keys  18  are positioned at a scribe line  16 A surrounding the integrated circuit devices  16 , i.e., positioned on the semiconductor wafer  14  in a two-dimensional manner. 
     Referring to  FIG. 4 , which is a cross-sectional view of  FIG. 3  along a cross-sectional line I-I. The probe card  26  includes a circuit board  22  and a plurality of probe needles  24  configured to contact the test keys  18  of the semiconductor wafer  14  to collect electrical information of the integrated circuit devices  16 . In particular, the angular adjusting module  30  is configured to rotate the semiconductor wafer  14  around the probe card  20  substantially by 90 degrees. 
     Referring to  FIG. 5  and  FIG. 6 , the braces  34  of the angular adjusting module  30  may be laterally removed or rotated by the driving device  52  such that the braces  34  can hold a bottom surface of the semiconductor wafer  14 . In addition, the braces  34  can also be optionally configured to clip a peripheral of the semiconductor wafer  14 , instead of holding the bottom surface of the semiconductor wafer  14 . 
     Referring to  FIG. 7  and  FIG. 8 , the angular adjusting module  30  further includes a driving device  38  such as a step motor configured to rotate the ring-shaped member  32  such that the semiconductor wafer  14  can be rotated around the probe card  20  substantially by 90 degrees as the semiconductor wafer  14  is lifted from the wafer chuck  12  by braces  34 . For example, the driving device  38  may be configured to rotate the ring-shaped member  32  by gears  40  or by a belt  42 . 
       FIG. 9  to  FIG. 12  illustrate the operation of the probing apparatus  10  according to one embodiment of the present invention. First, the semiconductor wafer  14  is positioned on the wafer chuck  12  and the probe card  26  uses the probe needles  24  to contact the test keys  18  positioned in one direction (for example, in the X-axis direction) to collect electrical information of the integrated circuit devices  16 . Subsequently, as the probe card  26  completes the information collection from the test keys  18  in the X-axis direction, the elevator  50  moves the wafer chuck  12  vertically downward such that the semiconductor wafer  14  is lifted from the wafer chuck  12  by the braces  34  holding the bottom surface of the semiconductor wafer  14 , as shown in  FIG. 10 . In addition, the semiconductor wafer  14  can be lifted from the wafer chuck  12  by using the driving device  52  to elevate the braces  34  upward to hold the bottom surface of the semiconductor wafer  14 . 
     Referring to  FIG. 11 , the driving device  38  of the angular adjusting module  30  rotates the semiconductor wafer  14  around the probe card  26  substantially by 90 degrees such that the other test keys  18  on the Y-axis direction are aligned to the probe needles  24  of the probe card  26 , and the elevator  50  then moves the wafer chuck  12  vertically upward such that the semiconductor wafer  14  is disposed on the wafer chuck  12  and the braces  34  release the semiconductor wafer  14 , as shown in  FIG. 12 . In addition, the semiconductor wafer  14  can be placed on the wafer chuck  12  by using the driving device  52  to move the braces  34  downward to release the semiconductor wafer  14 . 
     Subsequently, the probe card  26  uses the probe needles  24  to contact the test keys  18  positioned in the Y-axis direction to collect electrical information of the integrated circuit devices  16 . Consequently, the probing apparatus  10  can collect electrical information of the integrated circuit devices  16  via the test keys  18  arranged in a two-dimensional manner with the semiconductor wafer  14  undergoing a single test process. 
     The above-described embodiments of the present invention are intended to be illustrative only. Numerous alternative embodiments may be devised by those skilled in the art without departing from the scope of the following claims.