Abstract:
There is provided a method of manufacturing a probe card, the method including: providing a first substrate including a plurality of probe pin patterns for forming a probe pin and at least one first stress relieving groove for relieving thermal stress; forming the probe pin by filling a metal material in the plurality of probe pin patterns; bonding a surface of the first substrate where the probe pin is formed onto a surface of a second substrate; and transferring the probe pin onto the second substrate by heating the first and second substrates bonded together.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority of Korean Patent Application No. 2008-84651 filed on Aug. 28, 2008, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a probe card and a manufacturing method of the same, and more particularly, to a probe card capable of ensuring less damage to a probe pin and a manufacturing method of the same. 
         [0004]    2. Description of the Related Art 
         [0005]    A general semiconductor test device includes a tester, a performance board and a probe card and tests electrical properties of chips fabricated on a wafer. Also, the probe card of the semiconductor test device receives a signal generated from the tester through the performance board, transfers the signal to pads of the chip and transfers a signal outputted from the pads of the chip to the tester through the performance board. 
         [0006]    To manufacture a conventional probe card, a probe pin is formed on a silicon substrate, and then the probe pin is bonded to a ceramic substrate. Specifically, a metal material is deposited or plated on the silicon substrate to form the probe pin. Also, the probe pin is bonded to a bump formed on the ceramic substrate. At this time, a temperature of about 300° C. is applied to perform eutectic bonding. In this process, the silicon substrate and the ceramic substrate suffer stress due to thermal expansion. This stress generated deforms the probe pin formed on the silicon substrate or alters a position of the probe pin. Moreover, the ceramic substrate also suffered stress which causes the probe pin not to be bonded at a precise position, thereby leading to bonding defects. 
       SUMMARY OF THE INVENTION 
       [0007]    An aspect of the present invention provides a manufacturing method of a probe substrate, in which a first substrate including at least one stress relieving groove for relieving thermal stress formed between a plurality of probe pins is employed to transfer the probe pins onto a second substrate, thereby ensuring less deformation of the probe pins. 
         [0008]    An aspect of the present invention also provides a probe substrate including at least one stress relieving groove formed on a ceramic substrate where probe pins are bonded to relieve thermal stress to thereby enhance a bonding strength of the probe pins, and a manufacturing method of the same. 
         [0009]    According to an aspect of the present invention, there including: providing a first substrate including a plurality of probe pin patterns for forming a probe pin and at least one first stress relieving groove for relieving thermal stress; forming the probe pin by filling a metal material in the plurality of probe pin patterns; bonding a surface of the first substrate where the probe pin is formed onto a surface of a second substrate; and transferring the probe pin onto the second substrate by heating the first and second substrates bonded together. The first substrate may be a silicon substrate. 
         [0010]    The first stress relieving groove may be opened from a top to bottom of the first substrate. Also, the first stress relieving groove may include a plurality of stress relieving grooves. The plurality of first stress relieving grooves may be formed between the probe pin patterns on the first substrate. 
         [0011]    The second substrate may be a ceramic substrate having a multilayer circuit structure. The second substrate may include at least one second stress relieving groove for relieving thermal stress. The second substrate may include a bonding metal layer formed on an area where the probe pin is to be transferred. The bonding metal layer may include at least one material selected from a group consisting of Au, Sn, Pb, Ni, Ag, Ti and a combination thereof. 
         [0012]    According to another aspect of the present invention, there is provided a probe card including: a ceramic substrate including a stress relieving groove formed on a top thereof to relieve thermal stress; and a plurality of probe pins formed on the ceramic substrate, the plurality of probe pins each including a probe body part and a probe tip part. The stress relieving groove may be formed between the probe pins on the ceramic substrate. 
         [0013]    The ceramic substrate may include a bonding metal layer for bonding the probe pins together. The bonding metal layer may include at least one material selected from a group consisting of Au, Sn, Pb, Ni, Ag, Ti and a combination thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0015]      FIG. 1  illustrates a probe card according to an exemplary embodiment of the invention; and 
           [0016]      FIGS. 2A to 2H  illustrate a method of manufacturing a probe card according to an exemplary embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0017]    Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
         [0018]      FIG. 1  illustrates a probe card according to an exemplary embodiment of the invention. Referring to  FIG. 1 , the probe card  100  includes a ceramic substrate  110 , a bonding metal layer  120 , a plurality of probe pins  130  and stress relieving grooves  140 . Specifically, the ceramic substrate  110  includes a multilayer circuit structure (not shown) formed therein to be electrically connected to the probe pins  130  inside. Also, a test signal transmitted through the multilayer circuit is transferred to each of the probe pins  130  to measure electrical properties of an object of inspection. 
         [0019]    The bonding metal layer  120  serves to bond the ceramic substrate  110  to the probe pin  130 . Here, the bonding metal layer  120  may be formed of at least one material selected from a group consisting of Au, Sn, Pb, Ni, Ag, Ti and a combination thereof. 
         [0020]    Referring to a magnified view of the probe pin  130 , the probe pin  130  includes a probe body part  130   a  connected to the bonding metal layer  120  and a probe tip part  130   b  connected to a front end of the probe body part  130   a . Here, the probe tip part  130   b  is in contact with the object of inspection such as a semiconductor chip and transfers the test signal, and receives a result signal from the object of inspection to measure electrical properties. 
         [0021]    Meanwhile, the stress relieving grooves  140  formed on a top of the ceramic substrate  110  serve to relieve thermal  110 . The ceramic substrate  110  has a thermal expansion coefficient of about 5.4 to 5.8 ppm/° C. and has a volume changed according to an increase in temperature. This change in volume generates stress in the ceramic substrate  110 . The stress relieving grooves  140  absorb such a change in volume through an inner space thereof. Accordingly, this prevents the probe pins  130  from being detached from the ceramic substrate  110  or deformed. Therefore, each of the stress relieving grooves  140  may be formed between the plurality of probe pins  130 . 
         [0022]      FIGS. 2A to 2H  illustrate a method of manufacturing a probe card according to an exemplary embodiment of the invention. Referring to  FIGS. 2A , a plurality of probe pin patterns  210  are formed on a first substrate  200  using photo lithography. These patterns  210  are employed to form the probe pins and may be shaped corresponding to the probe pins. Also, the first substrate  200  may utilize a silicon substrate. 
         [0023]    Thereafter, as shown in  FIG. 2B , an area of the first substrate  200  where the plurality of probe pin patterns  210  are not formed is etched to form first stress relieving grooves  220  between the probe pin patterns  210 . Here, the first stress relieving grooves  220  may be extended to a predetermined depth of the first substrate  200 . Alternatively, the first stress relieving grooves  220  may be configured as a through hole opened from a top to bottom of the first substrate  200 . Moreover, the the first substrate  200  to have various shapes such as a triangle, a square and a circle. 
         [0024]    Meanwhile, the first stress relieving grooves  220  formed in the top of the first substrate  200  relieve a thermal stress when a heat is applied to the first substrate  200 . Specifically, the silicon substrate used as the first substrate  200  has a thermal expansion coefficient of 4.0 to 4.4 ppm/° C. and has a volume changed according to an increase in temperature. This change in volume generates a stress in the first substrate  200 . 
         [0025]    The first stress relieving grooves  220  relieve stress through an inner space thereof when a heat is applied to the first substrate  200 . Here, the first stress relieving grooves  220  are configured as a through hole to ensure thermal stress is relieved more effectively through the inner space thereof. 
         [0026]    Next, as shown in  FIG. 2C , a metal material is filled in each of the probe pin patterns  210  to form probe pins  230 . To fill the metal material, a conductor paste may be filled in the patterns or the metal material may be plated. Here, the metal material for forming the probe pins  230  may adopt Cu, Pt, Pa, Ni, Ag or Au. 
         [0027]      FIG. 2D  illustrates a top of the first substrate  200  shown in  FIG. 2C . As shown in  FIG. 2D , each of the plurality of stress relieving grooves  220  are formed between corresponding ones of the plurality of probe pins  230 . Accordingly, an area of the first substrate  200  where the probe pins  230  are located suffers relatively less thermal stress, thereby preventing the probe pins  230  from being impaired or deformed. 
         [0028]    Furthermore, referring to  FIG. 2D , the stress relieving grooves  220  are positioned between the probe pins  230  arranged in a row to form a uniform arrangement. Also, the first stress relieving grooves  220  have an identical shape and size. However, the first stress relieving grooves  220  may be arranged irregularly and may have a different shape and size. 
         [0029]    Afterwards, as shown in  FIG. 2E , second stress relieving grooves  310  are formed on a second substrate  300 . Here, the second substrate  300  may employ a ceramic substrate. 
         [0030]    Moreover, the second stress relieving grooves  310  formed on the second substrate  300  serve to relieve thermal stress in the same manner as the first stress relieving grooves  220  of the first substrate  200 . 
         [0031]    Subsequently, as shown in  FIG. 2F , bonding metal layers  320  are formed on the second substrate  300 . The bonding metal layers  320  are an area onto which the probe pins  230  of the first substrate  200  are transferred when the first substrate  200  and the second substrate  300  are bonded together. Therefore, the bonding metal layers  320  may be formed at positions corresponding to the probe pins  230  formed on the first substrate  200 . Here, the bonding metal layers  320  may include at least one material selected from a group consisting of Au, Sn, Pb, Ni, Ag, Ti and a combination thereof. 
         [0032]    Thereafter, as shown in  FIG. 2G , the first substrate  200  is bonded to the second substrate  300 . Also, a heat of about 300° C. is applied to perform eutectic bonding in order to ensure that the probe pins  230  of the first substrate  200  are bonded to the bonding metal layers  320  of the second substrate. In this process, the first and second substrates  200  and  300  are changed in volume, respectively due to an increase in temperature. At this time, the first and second stress relieving grooves  220  and  310  formed in the first and second substrates  200  and  300 , respectively absorb the changes in volume through inner spaces thereof to relieve thermal stress. This allows the probe pins  230  of the first substrate  200  to be transferred stably onto the bonding metal layers  320  of the second substrate  300 . 
         [0033]    As described above, the first and second stress relieving grooves  220  and  310  formed in the first and second substrates  200  and  200 , respectively serve to reduce thermal stress. Accordingly, this prevents the probe pins  230  of the first substrate  200  and the bonding metal layers  320  of the second substrate  300  from being damaged or changed in position or configuration. Consequently this allows the probe pins  230  to be bonded at accurate positions without undergoing any damage, thereby producing a probe card  400  with higher reliability. 
         [0034]    As set forth above, according to exemplary embodiments of the invention, a stress relieving groove is formed in at least one of first and second substrates to relieve thermal stress. The stress relieving groove serves to diffuse stress occurring due to a heat applied. Therefore, a probe pin formed on the first substrate, when transferred onto the second substrate, suffers less damage or deformation. Also, this increases a bonding strength of the probe pin and thus enhances reliability of a probe card. 
         [0035]    While the present invention has been shown and described in connection with the exemplary embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.