Abstract:
A method for manufacturing a probe structure is wherein a disclosed. In accordance with method, two semiconductor substrates having different crystal directions are bonded and selectively etched utilizing an etch selectivity due to the different crystal directions to form a probe tip region and a probe beam region. A cantilever structure for a probe card is formed by filling the probe tip region and the probe beam region with a conductive material.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a method for manufacturing a probe structure, and more particularly to a method for manufacturing a probe structure wherein a wet etching process is facilitated by bonding two semiconductor substrates having different crystal directions to form the probe structure. 
         [0003]    2. Description of the Related Art 
         [0004]    As a semiconductor technology progresses, a density of a cantilever structure used for a probe card is also increasing. Generally, a conventional method for forming the cantilever structure includes forming a mask layer pattern defining the cantilever structure is formed on a silicon substrate, etching the silicon substrate using the mask layer pattern as an etching mask, and filling the etched portion of the silicon substrate. 
         [0005]    However, a drawback of the conventional method is that a selective etching process is difficult to carry out because only one silicon substrate is used. Particularly, when a tip region of the cantilever structure is etched, a beam region of the cantilever structure is also etched. In order to overcome the drawback, a separate mask layer covering the beam region should be formed. Therefore, the etching process is complex and a cost thereof is increased. 
       SUMMARY OF THE INVENTION 
       [0006]    It is an object of the present invention to provide a method for manufacturing a probe structure wherein a wet etching process is facilitated by bonding two semiconductor substrates having different crystal directions to form the probe structure. 
         [0007]    In accordance with the present invention, there is provided a method for manufacturing a probe structure, the method comprising steps of: (a) bonding a first semiconductor substrate having a first crystal direction and a second semiconductor substrate having a second crystal direction different from the first crystal direction; (b) etching the second semiconductor substrate and the first semiconductor substrate to form a probe tip region; (c) etching the second semiconductor substrate to form a probe beam region; and (d) filling the probe tip region and the probe beam region to form a probe structure including a probe tip and a probe beam. 
         [0008]    It is preferable that the first semiconductor substrate includes a silicon substrate having a crystal direction of &lt;100&gt; and the second semiconductor substrate includes a silicon substrate having a crystal direction of &lt;111&gt;. 
         [0009]    Preferably, the step (b) comprises: (b-1) forming a second protective layer pattern on the second semiconductor substrate, the second protective layer pattern defining the probe tip region; (b-2) etching the second semiconductor substrate using the second protective layer pattern as a mask to expose the first semiconductor substrate; (b-3) etching the exposed first semiconductor substrate; and (b-4) removing the second protective layer pattern. 
         [0010]    It is preferable that the second protective layer pattern comprises one of a TEOS (Tetra Ethyl Ortho Silicate) layer and a polymer layer. 
         [0011]    Preferably, the step (c) comprises: (c-1) forming a first protective layer pattern on the second semiconductor substrate, the first protective layer pattern defining the probe beam region; (c-2) etching the second semiconductor substrate using the first protective layer pattern as a mask; and (c-3) removing the first protective layer pattern. 
         [0012]    It is preferable that the first protective layer pattern comprises one of a TEOS (Tetra Ethyl Ortho Silicate) layer and a polymer layer. 
         [0013]    The method in accordance with the present invention may further comprise: forming an insulation film in the probe beam region and the probe tip region; removing the insulation film at bottom portions of the probe beam region and the probe tip region; and etching the first semiconductor substrate at the bottom portion of the probe tip region after carrying out the step (c). 
         [0014]    Preferably, the removal of the insulation film comprises a wet etching process. 
         [0015]    It is preferable that the insulation film comprises one of an oxide film and a nitride film. 
         [0016]    The method in accordance with the present invention may further comprise etching the first semiconductor substrate at a bottom portion of the probe tip region after carrying out the step (c). 
         [0017]    Preferably, the etching of the insulation film comprises a wet etching process. 
         [0018]    It is preferable that the step (d) comprises: (d-1) forming a seed layer on surfaces of the probe beam region and the probe tip region; and (d-2) carrying out an electroplating process to form the probe structure. 
         [0019]    The method in accordance with the present invention may further comprise planarizing the second semiconductor substrate to reduce a thickness of the second semiconductor substrate after carrying out the step (a). 
         [0020]    In accordance with the present invention, there is also provided a method for manufacturing a probe structure, the method comprising steps of: (a) bonding a first semiconductor substrate having a crystal direction of &lt;100&gt; and a second semiconductor substrate having a crystal direction of &lt;100&gt;; (b) sequentially forming a first protective layer pattern and a second protective layer pattern on the second semiconductor substrate, the first protective layer pattern and the second protective layer pattern defining the probe beam region and the probe tip region, respectively; (c) etching the second semiconductor substrate and the first semiconductor substrate using the second protective layer pattern as a mask to form the probe tip region; (d) removing the second protective layer pattern; (e) etching the second semiconductor substrate using the first protective layer pattern as the mask to form the probe beam region; (f) removing the first protective layer pattern; (g) forming an insulation film in the probe beam region and the probe tip region; (h) removing the insulation film at bottom portions of the probe beam region and the probe tip region; (i) etching the first semiconductor substrate at the bottom portion of the probe tip region; (j) filling the probe tip region and the probe beam region to form a probe structure including a probe tip and a probe beam. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIGS. 1   a  through  1   k  are cross-sectional views illustrating a method for manufacturing a probe structure in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    The present invention will now be described in detail with reference to the accompanied drawings. The interpretations of the terms and wordings used in Description and Claims should not be limited to common or literal meanings. The embodiments of the present invention are provided to describe the present invention more thoroughly for those skilled in the art. 
         [0023]      FIGS. 1   a  through  1   k  are cross-sectional views illustrating a method for manufacturing a probe structure in accordance with the present invention. 
         [0024]    Referring to  FIG. 1   a , a first semiconductor substrate  100  having a first crystal direction and a second semiconductor substrate  110  having a second crystal direction. The first crystal direction differs from the second crystal direction. For instance, the first semiconductor substrate  100  may be a silicon substrate having a crystal direction of &lt;100&gt; and the second semiconductor substrate  110  may be a silicon substrate having a crystal direction of &lt;111&gt;. When the semiconductor substrates having the different crystal directions are used, a selective etching process is facilitated. Therefore, a desired portion of the substrate may be accurately etched to a desired depth. In addition, after bonding the first semiconductor substrate  100  and the second semiconductor substrate  110 , the second semiconductor substrate  110  may be planarized via a CMP (Chemical Mechanical Polishing) process to reduce a thickness of the second semiconductor substrate  110  until the thickness of the second semiconductor substrate  110  is that of a probe beam to be formed. 
         [0025]    Referring to  FIG. 1   b , a first protective layer  120  is formed on the second semiconductor substrate  110 . It is preferable that the first protective layer  120  may include one of a TEOS (Tetra Ethyl Ortho Silicate) layer and a polymer layer. 
         [0026]    Referring to  FIG. 1   c , a photoresist film pattern (not shown) defining a probe beam region is formed on the first protective layer  120  and the first protective layer  120  is then etched using the photoresist film pattern as a etching mask to form a first protective layer pattern  120   a  defining a probe beam region  150 . Thereafter, the photoresist film pattern is removed. 
         [0027]    Referring to  FIG. 1   d , a second protective layer (not shown) is formed on an entire surface of the second semiconductor substrate  110  including the first protective layer pattern  120   a , and a photoresist film pattern (not shown) defining a probe tip region is formed on the second protective layer. It is preferable that the second protective layer may include one of the TEOS (Tetra Ethyl Ortho Silicate) layer and the polymer layer. 
         [0028]    Thereafter, the second protective layer is etched using the photoresist film pattern as the etching mask to form a second protective layer pattern  130   a  defining the probe tip region  160 . Thereafter, the photoresist film pattern is removed. 
         [0029]    Referring to  FIG. 1   e , the second semiconductor substrate  110  is etched using the second protective layer pattern  130   a  as the etching mask until the first semiconductor substrate  100  is exposed. Thereafter, the exposed first semiconductor substrate  100  is etched to form a probe tip region  140 . The second protective layer pattern  130   a  is then removed. 
         [0030]    Referring to  FIG. 1   f , a predetermined thickness of the second semiconductor substrate is etched  110  using the first protective layer pattern  120   a  as the etching mask to form the probe beam region  150 . Thereafter, the first protective layer pattern  120   a  is removed. 
         [0031]    Referring to  FIG. 1   g , an insulation film  160  is formed in the probe beam region  150  and the probe tip region  140 . it is preferable that the insulation film  160  comprises an oxide film or a nitride film. 
         [0032]    Referring to  FIG. 1   h , the insulation film  160  at bottom portions of the probe beam region  150  and the probe tip region  140  is removed. It is preferable that the removal of the insulation film  160  is carried out by a wet etching process. 
         [0033]    Referring  FIG. 1   i , the first semiconductor substrate  100  at the bottom portion of the probe tip region  140  is etched. It is preferable that the etching process of the first semiconductor substrate  100  is carried out by the wet etching process. Because an etching characteristic of the first semiconductor substrate  100  differs from that of the second semiconductor substrate  110  due to the different crystal directions, the etching process of  FIG. 1   i  may be carried out selectively for the first semiconductor substrate  100 . Therefore, an accurate etching process is possible even when the wet etching is employed. 
         [0034]    Referring to  FIG. 1   j , a seed layer  170  is formed on surfaces of the probe beam region  150  and the probe tip region  140 . 
         [0035]    Referring to  FIG. 1   k , the probe tip region  140  and the probe beam region  150  are filled up with a conductive material to form a probe structure  180  including a probe tip and a probe beam. It is preferable that the probe structure  180  is formed via an electroplating process. 
         [0036]    Although not shown, the probe structure may be bonded to a space transformer, and the first semiconductor substrate  100  and the second semiconductor substrate  110  are then removed to form a probe card. 
         [0037]    As described above, the method in accordance with the present invention is advantageous in that the wet etching process is facilitated and a manufacturing cost is reduced by bonding the two semiconductor substrates having the different crystal directions to form the probe structure.