Patent Publication Number: US-2010112787-A1

Title: Method of manufacturing semiconductor device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This U.S. non-provisional patent application claims priority under 35 U.S.C §119 to Korean Patent Application No. 10-2008-0109864, filed in the Korean Intellectual Property Office on Nov. 6, 2008, the entirety of which is hereby incorporated by reference. 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to methods for manufacturing semiconductor devices and, more specifically, relates to a die separation method for dividing a semiconductor substrate into unit chips. 
     2. Description of Related Art 
     When semiconductor integrated circuit chips (IC chips) are formed on a wafer-level semiconductor substrate (i.e., wafer), a die separation process is performed to separate the wafer into a plurality of unit chips. The die separation process may include a mechanical wafer cutting approach using a blade or a wafer cutting approach using laser. 
     SUMMARY 
     Embodiments of the present invention provide a method of manufacturing a semiconductor device. In some embodiments of the present invention, the method may include preparing a substrate having a front surface where a circuit pattern is formed and a back surface opposite to the front surface. An image pickup member may read information of the circuit pattern formed at the front surface of the substrate, over the back surface, through the substrate. A cutting part may be formed at the back surface of the substrate. The back surface may be ground to form a portion of the cutting part as a dicing line. An expanding tape may be attached to the back surface where the dicing line is formed. The expanding tape is expanded to separate the substrate into a plurality of chips along the dicing line. 
     In one embodiment, grinding the back surface comprises grinding the back surface where the cutting part is formed to a determined depth. 
     In one embodiment, forming a cutting part may be conducted using either one of a blade and laser. 
     In one embodiment, preparing a substrate further comprises forming oxide at the back surface of the substrate, and reading information of the circuit pattern formed at the front surface of the substrate comprises recognizing an align key of the front surface through the oxide. 
     In one embodiment, the image pickup member includes a near infrared (NIR) camera. 
     In one embodiment, dicing the substrate comprises pressurizing the expanding tape in a direction perpendicular to the substrate to apply a pressure in a direction horizontal to the substrate. 
     In one embodiment, preparing a substrate further comprises forming oxide at the back surface of the substrate, and grinding the back surface includes removing the oxide. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features and advantages of the invention will be apparent from the more particular description of preferred aspects of the invention, 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. In the drawings, the thickness of layers and regions are exaggerated for clarity. 
         FIG. 1  is a flowchart illustrating a method for manufacturing a semiconductor device according to some embodiments of the present invention. 
         FIGS. 2A to 2E  are cross-sectional views illustrating the process of manufacturing a semiconductor device according to some embodiments of the present invention. 
         FIG. 3  illustrates a package module including a semiconductor package according to the present invention. 
         FIG. 4  is a block diagram of an electronic system including a semiconductor device according to some embodiments of the present invention. 
         FIG. 5  is a block diagram of a memory system including a semiconductor device according to some embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention, however, may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this description will be thorough and complete, and will fully convey the invention to those skilled in the art. Like numbers refer to like elements throughout. 
       FIG. 1  is a flowchart illustrating a method for manufacturing a semiconductor device according to some embodiments of the present invention.  FIGS. 2A to 2E  are cross-sectional views illustrating the process of manufacturing a semiconductor device according to some embodiments of the present invention. 
     Referring to  FIGS. 1 and 2A , a substrate  110  is prepared (S 110 ). Preparing the substrate  110  may include preparing a substrate where electrical devices are formed. For instance, preparing the substrate  110  may include preparing a wafer-level semiconductor substrate where semiconductor integrated circuit chips (not shown) are formed. The substrate  110  may have a front surface  112  and a back surface  114  which are opposite to each other. Circuit patterns (not shown) for forming the semiconductor integrated circuit chips may be formed at the front surface  112 . Preparing the substrate  110  may further include forming a thin film on the back surface  114 . The thin film may include oxide and be provided to protect the back surface  114 . 
     The substrate  110  may be placed on a support member  120  such that the front surface  112  and the support member  120  face each other (S 120 ). The back surface  114  of the substrate  110  may be exposed to the exterior. The support member  120  may be a plate supporting the substrate  110 . For instance, a surface plate may be used as the support member  120 . 
     Referring to  FIGS. 1 and 2B , an image pickup member  130  may read information of a pattern formed at the front surface  112  of the substrate  110 , over the back surface  114  of the substrate  110  (S 130 ). For example, the image pickup member  130  may be placed over the back surface  114  of the substrate  110 . In order to read the pattern information of the front surface  112  of the substrate  110 , the image pickup member  130  must pick up an image of the front surface  112  through the substrate  110 . However, because a thin film such as oxide may be formed on the back surface  114  of the substrate  110 , a typical microscope is not capable of picking up an image through the substrate  110 . For this reason, the image pickup member  130  may employ an apparatus which is capable of transmitting the back surface  114  on which the thin film is formed. For instance, the image pickup member  130  may employ a near infrared camera (NIR camera). The image pickup member  130  may be disposed on the back surface  114  to recognize an align key formed on the front surface  112  even while being supported by the support member  120 . 
     A cutting part  116  may be formed at the back surface  114  of the substrate  110  (S 140 ). The cutting part  116  allows semiconductor integrated circuit chips formed at the substrate  110  to be separated into unit chips. In an exemplary embodiment, forming the cutting part  116  may include forming a groove at the back surface  114  of the substrate  110 . The groove may have a line shape. In another exemplary embodiment, forming the cutting part  116  may include forming a groove at the back surface  114  of the substrate  110  using laser (not shown). According to the present invention, the cutting part  116  is formed at the back surface  114  of the substrate  110  to prevent damage of circuit patterns formed on the front surface  112  of the substrate  110 , as compared to the case where a groove is formed on the front surface  112  of the substrate  110 . 
     Referring to  FIGS. 1 and 2C , the back surface of the substrate  110  may be ground (S 150 ). In an exemplary embodiment, the front surface  112  of the substrate  110  is disposed to face the support member  120  and thus the back surface  114  may be exposed to the exterior. A grinder  150  may grind the entire surface of the exposed back surface  114  to a determined depth. The oxide formed at the back surface  114  may be removed partially or entirely by grinding the entire surface of the exposed back surface  114 . The grinder  150  grinds the back surface  114  such that a portion of the cutting part  116  remains and thus a dicing line  117  may be formed on the back surface  114 . The dicing line  117  may be a groove having a smaller depth than the cutting part  116 . The dicing line  117  may be a portion separating the substrate  110  during a die separation process. When the surface grinding process is completed, the substrate  110  may be separated from the support member  120 . 
     Referring to  FIGS. 1 and 2D , the back surface  114  of the substrate  110  may be attached onto an expanding tape  160  (S 160 ). It is noted that the orientation of the structure as shown in  FIG. 2D  is inverted from that of  FIG. 2C . The front surface  112  of the substrate  110  may be exposed to the exterior and the dicing line  117  formed at the back surface  114  of the substrate  110  may be disposed to face the expanding tape  160 . The expanding tape  160  may be provided to dice the substrate  110 . The expanding tape  160  may contain an expandable and shrinkable material that may be adhered to the substrate  110 . For instance, the expanding tape  160  may contain a die-attach adhesive film (DAF). An edge portion of the expanding tape  160  may be fixed by a tape support  162 . 
     Referring to  FIGS. 1 and 2E , the substrate  110  may be diced (S 170 ). In an exemplary embodiment, a pressure P is applied to the expanding tape  160  in a direction perpendicular to a surface of the substrate  110  to expand the expanding tape  160 . As the expanding tape  160  is expanded by the pressure P, the substrate  110  may receive a pressure in left and right directions X 1  and X 2 . Accordingly, the substrate  110  may be separated into a plurality of unit chips along the dicing line  117 . Through the above-described process, a plurality of semiconductor devices  100  each having the unit chip may be manufactured. 
     As set forth above, the substrate  110  is diced after forming the cutting part  116  and the dicing line  117  at the back surface of the substrate  110 . Thus, damage of patterns formed at the front surface  112  of the substrate  110  may be suppressed during the formation of the cutting part  116  and the dicing line  117 . 
     The foregoing semiconductor device and fabrication technology may be applied to various types of semiconductor devices and package modules including the same.  FIG. 3  illustrates a package module  200  including a semiconductor package according to the present invention. The package module  200  may be provided as a device including one or more semiconductor integrated circuit chips  220  and/or one or more semiconductor integrated circuit chips  230  packaged by quad flat packaging (QFP). The semiconductor device  100  manufactured according to the present invention may be included in various types of separate semiconductor devices  220  and  230 . The package module  200  may be formed by installing the semiconductor devices  220  and  230  at a separate semiconductor substrate  210 . The package module  200  may be connected to an external electronic device through an external connector  240  disposed at one side of a semiconductor substrate  210 . 
     The foregoing semiconductor device and fabrication technology may be applied to an electronic system.  FIG. 4  is a block diagram of an electronic system  300  including a semiconductor device according to some embodiments of the present invention. The electronic system  300  may include a controller  310 , an input/output device  320 , and a memory device  330 . The controller  310 , the input/output device  320 , and the memory device  330  may be connected via a bus  350 . The bus  350  may be a path through which data are delivered. As at least one microprocessor, the controller  310  may include at least one selected from the group consisting of, for instance, a digital signal processor, a microcontroller, and logic devices which are capable of performing similar functions thereto. The controller  310  and the memory device  330  may include a semiconductor device  100  manufactured by the method according to the present invention. The input/output device  320  may include at least one selected from the group consisting of a keypad, a keyboard, and a display device. The memory device  330  is a data storage device, which may store data and/or commands executed by the controller  310 . The memory device  330  may include a volatile memory device and/or a nonvolatile memory device. Alternatively, the memory device  330  may include a flash memory. For instance, a flash memory device adopting the technology according to the present invention may be mounted at a mobile device or a data processing system such as a desktop computer. Such a flash memory may be a solid-state disk (SSD). In this case, the electronic system  300  may stably store massive amounts of data in the flash memory system. The electronic system  300  may further include an interface  340  for transmitting data to a communication network or receiving data from the communication network. The interface  340  may be a wired interface or a wireless interface. For instance, the interface  340  may include an antenna or a wired/wireless transceiver. The electronic system  300  may further include an application chipset, a camera image processor (CIS), and/or an input/output device. 
     The electronic system  300  may be embodied as a mobile system, a personal computer (PC), an industrial computer or a logic system performing various functions. For instance, the mobile system may be one selected from the group consisting of a personal digital assistance (PDA), a portable computer, a web tablet, a mobile phone, a wireless phone, a laptop computer, a memory card, a digital music system, and a data transmitting/receiving system. In the case where the electronic system  300  is an apparatus which is capable of performing a wireless communication, it may be used in a communication interface protocol such as a three-generation communication system such as CDMA, GSM, NADC, E-TDMA, WCDMA, and CDMA2000. 
     A semiconductor device adopting the technology according to the present invention may be provided in form of a memory card.  FIG. 5  is a block diagram of a memory system including a semiconductor device according to some embodiments of the present invention. Referring to  FIG. 5 , a memory card  400  may include a memory device  410  including a semiconductor device according to the present invention and a memory controller  420 . The memory device  410  may include a nonvolatile memory device. The memory device  410  and he memory controller  420  may store data or read stored data. The memory controller  420  may control the memory device  410  to read stored data or store data in response to read/write request of a host  430 . 
     According to the present invention, a dicing process is performed by forming a dicing line at a back surface of a semiconductor substrate to enhance efficiency of a die separation process and prevent damage of patterns formed at the substrate during the die separation process. 
     Although the present invention has been described in connection with the embodiments of the present invention illustrated in the accompanying drawings, it is not limited thereto. It will be apparent to those skilled in the art that various substitutions, modifications and changes may be made without departing from the scope and spirit of the invention.