Abstract:
An apparatus for attaching an object semi-automatically onto a dummy wafer comprising a stage having a loading surface on which the dummy wafer rests, a pressing device for attaching the object gradually onto the dummy wafer placed on the loading surface, and a supporting device for placing the object in a position spaced apart from the loading surface.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus for attaching sand papers semi-automatically onto dummy wafers. 
     2. Description of Related Art 
     A probe card is one of the components that form an apparatus for the probe measurement employed in the course of manufacturing semiconductor devices such as transistors and integrated circuits. As shown in FIG. 6, the probing card  20  has a plurality of probes or tips  22  arranged so as to correspond to, and come into electrical contact with, a plurality of electrode pads of semiconductor devices fabricated on a semiconductor wafer, as the electrical characteristics of the semiconductor devices are tested. Because the contact between the electrode pads and the probes is a point contact having a small contact area, the ends of the probes  22  are rounded. Also, the ends of the probes  22  need to be polished in order to prevent them from oxidizing upon contact with air. The polishing is accomplished via a dummy wafer W on which a sand paper  10  is attached. 
     However, up until now, an operation to prepare the dummy wafer W for polishing, i.e., attaching the sand paper  10  to the dummy wafer W, has been manually carried out. Attaching the sand paper  10  manually to the dummy wafer W may present the following problems. First, after being attached to a dummy wafer, a surface of the sand paper is usually rubbed with a matter such as pieces of paper to enhance the degree of adhesion. As a result of this rubbing, contaminants or foreign substances can be accumulated on the surface of the sand paper deteriorating its function. Secondly, during the attaching, air bubbles can form between the sand paper and the dummy wafer. These air bubbles may impose an impact on the tips of the probes to induce a defect therein during polishing. Thirdly, the sand paper should optimally be attached onto the center of the dummy wafer correctly, as shown in FIG.  6 . Attaching the sand paper correctly, however, is not guaranteed when done manually and varies according to the skill or experience of workers. If it is not correctly attached onto the center of the dummy wafer, the resulting dummy wafers will be of inferior quality. Fourthly, it takes significant time to attach the sand paper onto the dummy wafer. For example, it takes a skilled worker one minute to attach one sheet of sand paper. Lastly, since the attaching method can be different according to workers, dummy wafers of inferior quality can thereby be made. 
     SUMMARY OF THE INVENTION 
     In order to solve the aforementioned problems, it is a feature of an embodiment of the present invention to provide a new apparatus that can easily attach an object onto a dummy wafer. 
     This and other features are provided, according to the present invention, by an apparatus for attaching an object semi-automatically onto a dummy wafer comprising a stage having a loading surface on which the dummy wafer rests, a pressing means for attaching the object gradually on the dummy wafer placed on the loading surface, and a support means for placing the object in a position spaced apart from the loading surface. 
     In a preferred embodiment of the present invention, the supporting means includes at least two supporting rods disposed to cross the loading surface at an angle to said loading surface for placing the object thereon, and side plates disposed on opposite sides of the stage for fixing both ends of the support rods. 
     The supporting means further includes a plurality of mini-rollers disposed on the support rods to allow the object to be easily slid without adhering to the support rods, and a pair of holders disposed apart from each other on the support rods for guiding both sides of the object so that the object may be slid down correctly. The holders are disposed such that the distance between them is adjustable in order to accommodate objects of differing sizes. 
     The two support rods of the supporting means may be disposed to be inclined, allowing the object to be placed on a slope thereon. 
     Also, the stage may have openings or grooves formed at an edge of the loading surface to load or unload the dummy wafer easily. The loading surface may also be disposed lower than an upper surface of the stage. 
     In an embodiment of the present invention, guide rails disposed at both sides of the stage allow the pressing means and the supporting means to be movable so that they may be slid in a direction that will allow the object to be attached onto the dummy wafer. 
     In the apparatus of an embodiment of the present invention, the pressing means includes a roller for attaching the object onto the dummy wafer, brackets for fixing both ends of the roller rotatably, and a handle connected with the brackets for moving the roller in the direction that will allow the object to be attached onto the dummy wafer. The roller is formed of material having a given elasticity to prevent the dummy wafer from being damaged and to increase the adhesion degree during the attaching of the object. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other features and advantages of the present invention will become more apparent by describing in detail preferred embodiments thereof as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. 
     FIG. 1 illustrates a schematic perspective view of an apparatus for attaching a sand paper on a dummy wafer in accordance with a preferred embodiment of the present invention. 
     FIG. 2 illustrates a top plan view of the attaching apparatus in accordance with an embodiment of the present invention. 
     FIG. 3 illustrates a side elevation view of the attaching apparatus in accordance with an embodiment of the present invention. 
     FIG.  4  and FIG. 5 illustrate diagrams showing the operation steps of attaching a sand paper onto a dummy wafer by the attaching apparatus of an embodiment of the present invention. 
     FIG. 6 illustrates a schematic diagram showing the operation of polishing tips of a probe card by means of the dummy wafer. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Korean Patent Application No. 2001-18968, filed on Apr. 10, 2001, and entitled: “Apparatus for Attaching Sand Papers on Dummy Wafers,” is herein incorporated by reference in its entirety. 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the present invention are shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully cover the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. 
     FIG. 1 illustrates a schematic perspective view of an apparatus  100  for attaching sand papers onto dummy wafers in accordance with a preferred embodiment of the present invention. FIG.  2  and FIG. 3 illustrate top plan and side elevation views, respectively, of the apparatus  100  shown in FIG.  1 . 
     The attaching apparatus  100  in accordance with a preferred embodiment of the present invention comprises a stage  110 , a pressing device  130 , and a supporting device  150 . 
     The stage  110  of the attaching apparatus  100  includes a loading surface  114  formed on an upper surface  112  of the stage  110  to load a dummy wafer W onto which a sand paper  10  is to be attached, as shown in FIG. 3 to FIG.  5 . The loading surface  114  is formed lower than the upper surface  112  of the stage  110  by as much as 0.6 mm. Also, on the upper surface  112  of the stage  110 , a position standard line  116  for defining a position of a lower end of the sand paper  10  is marked. In the vicinity of an edge of the loading surface  114 , four openings or grooves  118  are formed. Owing to the grooves  118 , the dummy wafer W can be easily loaded or unloaded onto or from the loading surface  114 . On both sides  113  of the stage  110 , guide rails  120  are disposed to guide the movement of the supporting device  150  and the pressing device  130 . 
     The supporting device  150  of the attaching apparatus  100  functions to maintain the sand paper  10  to be attached onto the dummy wafer W in a position spaced apart from the loading surface  114  and inclined at a given angle, preferably 60 degrees thereto, as shown in FIG.  3 . At this time, the lower end of the sand paper  10  is positioned to be aligned with the position standard line  116 . 
     The supporting device  150  includes two support rods  154 , two side plates  152 , a plurality of mini-rollers  156 , and a pair of holders  158 . The side plates  152  are mounted on the guide rails  120  which are positioned on opposite ends of the stage  110 . Both ends of the support rods  154  are fixed on the top ends of the side plates  152 . The support rods  154  are disposed to cross the loading surface  114  at an angle to said loading surface. The mini-rollers  156  are disposed on the support rods  154  to allow the sand paper  10  to be easily slid there onto, but not to be adhered thereto. The two holders  158  are disposed on the support rod  154  at a distance from each other. The distance between the two holders  158  can be adjusted according to the size of the sand paper  10 , e.g., 7 to 12 inches. Preferably, the holders  158  are formed of a “” shape to prevent the sand paper  10  from passing between the support rods  154 . Thus, since the two holders  158  guide both sides of the sand paper  10  to be correctly positioned as it is being slid onto the mini-rollers  156 , it can be attached onto a correct position on the dummy wafer W. 
     The pressing device  130  of the attaching apparatus  100  functions to press the sand paper  10  placed on the support rods  154  gradually by means of a roller  132  thereof, thereby attaching the sand paper  10  gradually onto an upper attaching surface of the dummy wafer W. 
     The pressing device  130  includes a roller  132  having a length wider than the width of the stage  110 , brackets  134  on which both ends of the roller  132  are rotatably fixed, and a handle  136  connected to the brackets  134  for moving the roller  132 . The brackets  134  are pivotally fixed on rear end portions of the side plates  152  and are to be slid along the guide rails  120  together with the side plates  152  of the supporting device  150 . The roller  132  can roll onto the upper attaching surface of the dummy wafer W when the brackets  134  move forward or in the direction of the arrow in FIG. 5 along the guide rails  120 . The roller  132  rolls together with the side plates  152 . At this time, the handle  136  is slowly pushed by the user to move the brackets  134  and the side plates  152  forward. Thus, the sand paper  10  positioned between the roller  132  and the dummy wafer W is gradually adhered onto the upper attaching surface of the dummy wafer W as the roller  132  is being rolled. 
     To restrain the movement of the rear end portions of the side plates  152  on which the brackets  134  are pivotally fixed, i.e. the movement of the brackets  134 , stoppers  122  can be disposed on the rails  120 . Accordingly, the movement of the roller  132  can be restrained within a given range. Also, a locking pin (not shown) for locking the roller  132  can be disposed on the upper surface  112  of the stage  110  to prevent the roller  132  from moving freely from a stand-by position after use. 
     The roller  132  is formed of material such as silicon or rubber having a given elasticity to prevent the dummy wafer W from being damaged, and to increase the adhesion density or degree when the roller  132  presses the sand paper  10  onto the upper attaching surface of the dummy wafer W. 
     The operation of the apparatus  100  for attaching sand paper onto dummy wafers in accordance with the present invention will now be explained. 
     FIG.  4  and FIG. 5 illustrate diagrams showing the operation steps of attaching a sand paper  10  onto a dummy wafer W by the attaching apparatus  100  of the present invention. 
     Referring to FIG.  4  and FIG. 5, first the dummy wafer W is loaded onto the loading surface  114  of the stage  110 . Then the sand paper  10  is placed on two support rods  154 . At this time, a lower end of the sand paper  10  is positioned to be aligned with the position standard line  116 , and both of its sides are positioned between the pair of holders  158 . Next, a user pushes the handle  136  forward or in the direction of the arrow in FIG.  5 . As the handle  136  is pushed, the roller  132  is rolled onto an upper attaching surface of the dummy wafer W along brackets  134  which move forward together with side plates  152  along guide rails  120 . At this time, the sand paper  10  positioned between the roller  132  and the dummy wafer W is gradually attached or adhered onto the upper attaching surface of the dummy wafer W from the lower end thereof until the movement of rear end portions of the side plates  152  are restrained by stoppers  122 . Thus, the sand paper  10  is uniformly attached onto the upper attaching surface of the dummy wafer W. 
     As is apparent from the foregoing description, it can be appreciated that the attaching apparatus of the present invention can prevent contaminants or foreign substances from accumulating on the surface of the sand paper. Further, the attaching apparatus of the present invention can prevent air bubbles from being generated between the sand paper and the dummy wafer. Also, the attaching apparatus of the present invention can attach the sand paper onto the center of the dummy wafer, reduce the operation time compared with the manual operation time, and obtain a uniform quality regardless of the skill or experience of users. 
     In the drawings and specification, a preferred embodiment of the present invention has been disclosed and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the following claims.