Abstract:
An apparatus for manufacturing a printed circuit board that uses conductive bumps to interconnect layers includes: a conveyor unit, which is configured to transport a board that has the conductive bumps formed on one side; an upper roller and a lower roller, which press the board and an insulator together; an elastic coating layer, formed on a surface of the upper roller; and a cleaning device, which removes impurities from a surface of the elastic coating layer. The apparatus does not require a separate device for performing a cushioning function and a detaching function between the bumps and the rollers, and the rollers can be kept clean using a cleaning device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Korean Patent Application No. 10-2007-0085774 filed with the Korean Intellectual Property Office on Aug. 24, 2007, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to an apparatus and a method for manufacturing a printed circuit board. 
     2. Description of the Related Art 
     In manufacturing a printed circuit board, the methods for interconnecting layers can include plating methods, in which holes are processed, such as by mechanical drilling or laser drilling, and then electroplating is performed, paste-filling methods, in which the holes are filled in with conductive paste, or Buried Bump Interconnection Technology (“B2it”) methods, in which conductive bumps are formed that are made to penetrate the insulation material. 
     Among these methods, the use of a B2it method may require a penetration apparatus to force the conductive bumps to penetrate the insulation material. Such penetration apparatus may face difficulties in implementing the penetration as the number of conductive bumps is increased. There is a demand also for apparatus that provides cushioning, as well as for apparatus that efficiently implements detachability with respect to the conductive bumps and the insulation material. 
     SUMMARY 
     An aspect of the invention is to provide an apparatus and a method for manufacturing a printed circuit board, which does not require a separate device for performing a cushioning function and a detaching function between the bumps and the rollers, and with which the rollers can be kept clean. 
     One aspect of the invention provides an apparatus for manufacturing a printed circuit board that uses conductive bumps for interconnection between layers. The apparatus includes: a conveyor unit, which is configured to transport a board that has the conductive bumps formed on one side; an upper roller and a lower roller, which press the board and an insulator together; an elastic coating layer, formed on a surface of the upper roller; and a cleaning device, which removes impurities from a surface of the elastic coating layer. 
     The elastic coating layer may contain silicon (Si) or Teflon, the cleaning device may include a cleaning roller that engages with the upper roller, and a thickness of the elastic coating layer may be greater than a height of the conductive bumps. The apparatus may further include a preheater for preheating the insulator. 
     Another aspect of the invention provides a method of manufacturing a printed circuit board that employs conductive bumps for interconnection between layers. The method includes: forming conductive bumps on one side of a board; loading an insulator onto the one side of the board; and pressing the insulator and the board together, where the pressing is performed by a lower roller, which supports the board, and an upper roller, which engages with the lower roller, and on a surface of which an elastic coating layer is formed. 
     The elastic coating layer may contain silicon (Si) or Teflon, and a thickness of the elastic coating layer may be greater than a height of the conductive bumps. Also, the method may further include preheating the insulator, before the pressing. 
     Additional aspects and advantages of the present invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating one embodiment of an apparatus for manufacturing a printed circuit board according to an aspect of the invention. 
         FIG. 2  is a flowchart illustrating one embodiment of a method of manufacturing a printed circuit board according to another aspect of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in drawings and described in detail in the written description. However, this is not intended to limit the present invention to particular modes of practice, and it is to be appreciated that all changes, equivalents, and substitutes that do not depart from the spirit and technical scope of the present invention are encompassed in the present invention. In the description of the present invention, certain detailed explanations of related art are omitted when it is deemed that they may unnecessarily obscure the essence of the invention. 
     The terms used in the present application are merely used to describe particular embodiments, and are not intended to limit the present invention. An expression used in the singular encompasses the expression of the plural, unless it has a clearly different meaning in the context. In the present application, it is to be understood that the terms such as “including” or “having,” etc., are intended to indicate the existence of the features, numbers, steps, actions, elements, parts, or combinations thereof disclosed in the specification, and are not intended to preclude the possibility that one or more other features, numbers, steps, actions, elements, parts, or combinations thereof may exist or may be added. 
     Embodiments of the apparatus and method for manufacturing a printed circuit board according to certain aspects of the invention will now be described below in more detail with reference to the accompanying drawings. Those components that are the same or are in correspondence are rendered the same reference numeral regardless of the figure number, and redundant explanations are omitted. 
     First, an embodiment of an apparatus for manufacturing a printed circuit board according to an aspect of the invention will be described as follows.  FIG. 1  is a schematic diagram illustrating one embodiment of an apparatus for manufacturing a printed circuit board according to an aspect of the invention. In  FIG. 1 , there are illustrated an upper roller  10 , an elastic coating layer  12 , a lower roller  20 , a conveyor belt  30 , boards  40 , conductive bumps  50 , insulators  60 , a preheater  70 , and cleaning rollers  80 . 
     The upper roller  10  and the lower roller  20  may engage with each other and provide rotating motions, to press together a board  40  and an insulator  60 , etc. The upper roller  10  and lower roller  20  can provide rotating motions while fixed in their respective positions. The object of pressing, such as the board  40  and the insulator  60 , etc., may be provided to the upper roller  10  and lower roller  20  by way of a conveyor unit, such as the conveyor belt  30 . 
     On the upper side of a board  40  transported by the conveyor belt  30 , conductive bumps  50  may be formed, which allow interconnection between layers. When the insulator  60  and the board  40  are pressed together by the upper roller  10  and lower roller  20  described above, the conductive bumps  50  can be made to penetrate the insulator  60 , to allow interconnection between the upper and lower sides of the insulator  60 . Thus, in cases where pre-designed circuit patterns are formed on either side of the insulator  60 , the circuit patterns (not shown) on either side may be electrically connected, due to the conductive bumps  50  that pass through the insulator  60 . 
     The upper roller  10  and the lower roller  20  can each be made of stainless steel. On a surface of the upper roller  10 , there may be formed an elastic coating layer  12 . The elastic coating layer  12  formed on the surface of the upper roller  10  can be made from a silicon (Si) or Teflon material, which provides high detachability. Forming the elastic coating layer  12  from a material high in detachability can help minimize the occurrence of separation between the conductive bumps  50  and insulator  60 . Of course, other heat-resistant detachable elastic materials, i.e. materials that have high elasticity and high detachability, can be used as the material for the elastic coating layer  12 . 
     The thickness of the elastic coating layer  12  can be greater than the height of the conductive bumps  50  formed on the board  40 . By forming the elastic coating layer  12  such that its thickness is greater than the height of the conductive bumps  50 , the conductive bumps  50  can be prevented from being deformed due to direct contact with the upper roller  10 , when the insulator  60  and the board  40  are pressed together by the upper roller  10  and the lower roller  20 . 
     Also, in order that the bumps  50  may efficiently penetrate the insulator  60 , the insulator  60  may be preheated, using a preheater  70 , before the board  40  and insulator  60  are pressed together. Using the preheater  70  to preheat the insulator  60 , the level of curing of the insulator  60  can be lowered, so that the insulator  60  may readily be penetrated by the conductive bumps during the pressing. 
     A cleaning device may be employed to remove impurities formed on the surface of the elastic coating layer  12 . When the insulator  60  and the board  40  having conductive bumps  50 , etc., are pressed together by the rotating motions of the lower roller  20  and upper roller  10 , impurities may form on the surface of the upper roller  10 , as they are separated from the conductive bumps  50  or from the insulator  60 . As such, the cleaning device may be used to prevent the accumulation of such impurities, so that the pressing by the upper roller  10  and lower roller  20  may continue in an efficient manner. 
     This particular embodiment presents cleaning rollers  80  that engage with the upper roller  10  as an example of a cleaning device, as illustrated in  FIG. 1 . 
     Next, the operation of the apparatus for manufacturing a printed circuit board according to this embodiment will be described as follows. When the insulator  60  and the board  40  having conductive bumps  50  formed on one side are transported by the conveyor belt  30 , the upper roller  10  and the lower roller  20 , using rotating motions, may press the board  40  and the insulator  60  together. When the board  40  and the insulator  60  are pressed, the conductive bumps  50  formed on the board  40  penetrate the insulator  60 , so that the upper and lower sides of the insulator  60  may be electrically connected. 
     Due to the elastic coating layer  12  formed on the surface of the upper roller  10 , problems that involve the conductive bumps  50  being deformed or detached, or the insulator  60  being separated, can be minimized. Also, the elasticity of the elastic coating layer  12  can facilitate the penetrating of the insulator  60  by the conductive bumps  50 . 
     Next, a method of manufacturing a printed circuit board according to another aspect of the invention will be described as follows with reference to  FIG. 2 . For better understanding, the method will be described for an example that uses the apparatus for manufacturing a printed circuit board described above.  FIG. 2  is a flowchart illustrating one embodiment of a method of manufacturing a printed circuit board according to another aspect of the invention. 
     First, conductive bumps  50  may be formed on one side of a board  40  (S 110 ), and an insulator  60  may be loaded onto the side of the board  40  (S 120 ). The conductive bumps  50  may penetrate the insulator  60  and may serve to electrically connect either side of the insulator  60 . These conductive bumps  50  can be formed on one side of the board  40  using an inkjet method or a screen printing method, etc. 
     Next, the insulator  60  and the board  40  may be pressed together (S 140 ). By thus pressing the insulator  60  and the board  40 , the conductive bumps  50  can be made to penetrate the insulator  60 . 
     Before pressing the insulator  60  and the board  40 , the insulator  60  may be preheated (S 130 ), in order that the insulator  60  may readily be penetrated by the conductive bumps  50 . By preheating the insulator  60  using the preheater  70 , the level of curing of the insulator  60  may be lowered, so that the conductive bumps  50  can be made to penetrate the insulator  60  with greater ease, during the pressing. 
     As described above, the process of pressing the insulator  60  and the board  40  can be performed by a lower roller  20  that supports the board  40 , and an upper roller  10  that engages with the lower roller  20  and has an elastic coating layer  12  formed on the surface. 
     The elastic coating layer  12  formed on the surface of the upper roller  10  can be made of a silicon (Si) or Teflon material, which is high in detachability, and the thickness of the elastic coating layer  12  can be made greater than the height of the conductive bumps  50 , as already described above. 
     According to certain embodiments of the invention as set forth above, there is no need for a separate device to perform a cushioning function and a detaching function between the bumps and the rollers, while the rollers can be kept clean using the cleaning device. 
     While the spirit of the invention has been described in detail with reference to particular embodiments, the embodiments are for illustrative purposes only and do not limit the invention. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the invention. 
     Many embodiments other than those set forth above are encompassed within the scope of claims of the present invention.