Abstract:
Disclosed herein a packaging method including: (A) forming a plurality of pads and another circuit pattern on a substrate; (B) forming a second dry film pattern including opening exposing the pad; (C) mounting a solder coating ball in the opening of the second dry film pattern; (D) performing a reflow process on the solder coating ball in order to allow the solder coating ball to have a modified pattern; (E) delaminating the second dry film pattern; and (F) forming a solder pattern including the modified pattern of the solder coating ball in a solder to mount a chip on the substrate using the solder pattern.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2012-0085823, filed on Aug. 6, 2012, entitled “Packaging Method Using Solder Coating-Ball and Package Thereby”, which is hereby incorporated by reference in its entirety into this application. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to a packaging method using a solder coating-ball and a package manufactured thereby. 
         [0004]    2. Description of the Related Art 
         [0005]    According to the prior art, a flip chip scheme in which a solder bump is formed on a printed circuit board (PCB) and then, a device is mounted thereon to thereby package them has been increasingly used 
         [0006]    In particular, in the case of a central processing unit (CPU) and a graphic operation device operating large capacity data at a high speed, a change from a scheme connecting between a substrate and a device using a gold (Au) wire according to the prior art to the flip chip scheme in which the substrate and the device are connected by the solder bump so as to improve connection resistance has been rapidly increased. 
         [0007]    Methods forming the solder bump as described above may be divided into a scheme forming the solder bump by printing a solder paste on the substrate and then reflowing the solder paste, a scheme forming the solder ball by mounting a fine solder ball on the substrate, and a method forming the solder bump by injecting a melted solder into the substrate directly or using a mask. The solder bump formed on the substrate as described above is melted so as to connect to a copper (Cu) pad or a solder bump formed on a chip, thereby coupling between metals. 
         [0008]    The methods forming the above-mentioned solder bump may include a ball placing scheme in which the same size openings having the same size are formed on the mask and then the solder ball is squeegeed using a squeegee, such that the solder ball is mounted on input/output pad of the substrate through the mask openings, or a scheme in which a vacuum hole having the same pattern as a substrate pattern is formed at a jig and then the solder ball is picked-up at vacuum so as to be mounted on the substrate, as described in Korea Patent Laid-Open Publication No. 2008-0014143(laid-open published on Feb. 13, 2008). 
         [0009]    However, as a pitch of the input/output pad of the substrate gradually becomes fine, a technology forming the solder bump on the input/output pad of the substrate using the solder ball or a paste according to the prior art has been gradually changed to a scheme forming the bump made of copper (Cu) using a plating and lithography technologies. 
         [0010]    The packaging method using the bump made of copper (Cu) using the above-mentioned plating and lithography technologies has a problem in that an interface between the solder and an electroless Cu is separated from each other due to low interface stability, such that processing stability is degraded. 
         [0011]    In addition, a plating thickness deviation occurring at the time of plating copper (Cu) leads to a height deviation between the solder and the copper (Cu) bump, such that connection reliability in the packaged chip is deteriorated. 
       SUMMARY OF THE INVENTION 
       [0012]    The present invention has been made in an effort to provide a packaging method improving connection reliability using a solder coating ball so as to solve the problems as mentioned above. 
         [0013]    Further, the present invention has been made in an effort to provide a package manufactured by a packaging method using a solder coating ball so as to solve the problems as mentioned above. 
         [0014]    According to a preferred embodiment of the present invention, there is provided a packaging method including: (A) forming a plurality of pads and another circuit pattern on a substrate; (B) forming a second dry film pattern including opening exposing the pad; (C) mounting a solder coating ball in the opening of the second dry film pattern; (D) performing a reflow process on the solder coating ball in order to allow the solder coating ball to have a modified pattern; (E) delaminating the second dry film pattern; and (F) forming a solder pattern including the modified pattern of the solder coating ball in a solder to mount a chip on the substrate using the solder pattern. 
         [0015]    Step (A) may include: (A-1) forming a first dry film pattern having openings corresponding to the pad and another circuit pattern; (A-2) filling the first dry film pattern with copper; (A-3) delaminating the first dry film pattern; and (A-4) forming a solder resist (SR) pattern enclosing a region of the pad and burying another circuit pattern. 
         [0016]    Step (A-2) may be performed by any one of a chemical vapor deposition (CVD) method, a physical vapor deposition (PVD) method, a subtractive method, an additive method using an electroless copper plating or electrolytic copper plating, a semi-additive process (SAP), and a modified semi-additive process (MSAP). 
         [0017]    Step (B) may include: (B-1) laminating a dry film in an uncured state on the substrate including the pad and another circuit pattern using a laminate; and (B-2) performing a patterning process on the laminated dry film. 
         [0018]    In step (D), the solder coating ball may be formed of a metal ball made of a conductive metal material and a solder coating film formed on an outer surface of the metal ball, wherein the solder coating film is melted and accumulated according to the reflow process to be adhered to the pad. 
         [0019]    The solder coating film may be provided by plating an outer surface of the metal ball with the solder by an electroplating method. 
         [0020]    According to another preferred embodiment of the present invention, there is provided a package including: a plurality of pads formed on a substrate; a solder resist (SR) pattern enclosing a region of the pad and burying another circuit pattern; a solder pattern including a metal pattern therein using a solder and formed on an upper surface of each of the pads; and a chip mounted on the substrate through the solder pattern. 
         [0021]    The solder pattern may include a metal pattern made of a conductive metal material in the solder. 
         [0022]    The chip may be formed at the same height from an upper surface of the substrate. 
         [0023]    The package may further include a post bump between the chip and the solder pattern. 
         [0024]    According to another preferred embodiment of the present invention, there is provided a packaging method including: (A) forming a plurality of pads and another circuit pattern on a substrate; (B) forming a second dry film pattern including an opening exposing the pad; (C) mounting a solder coating ball in the opening of the second dry film pattern; (D) performing a reflow process on the solder coating ball in order to allow the solder coating ball to have a modified pattern; (E) forming a solder pattern by filling and press-fitting the opening with a solder; (F) delaminating the second dry film pattern; and (G) mounting a chip on the substrate using the solder pattern. 
         [0025]    In step (E), the solder may be filled and press-fitted into the opening using a solder injector. 
         [0026]    The solder injector may include: a storing part storing the solder supplied from an outside; a discharging hole connected to the storing part in the form of a pipe to discharge the solder; a heating part enclosing and heating the discharging hole; and a press-fitting part allowing a melted solder discharged from the discharging hole to flow a surface of the press-fitting part to be injected, wherein the solder is filled and press-fitted into the openings using the press-fitting part. 
         [0027]    The storing part may be connected to a pressurization pump or a piston to discharge the solder into the discharging hole. 
         [0028]    The press-fitting part may be formed of an elastic material to squeeze along with an upper surface of the second dry film provided with the openings. 
         [0029]    In step (G), the chip may be mounted on the substrate by correspondingly adhering a post bump of the chip to the solder pattern. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0031]      FIG. 1  is a cross-sectional view showing a package according to a preferred embodiment of the present invention; 
           [0032]      FIGS. 2A to 2F  are cross-sectional views sequentially showing the process of a packaging method of a package according to a preferred embodiment of the present invention; 
           [0033]      FIG. 3  is a cross-sectional view showing a package according to another preferred embodiment of the present invention; and 
           [0034]      FIGS. 4A to 4G  are cross-sectional views sequentially showing the process of a packaging method of a package according to another preferred embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0035]    The objects, features and advantages of the present invention will be more clearly understood from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant descriptions thereof are omitted. Further, in the following description, the terms “first”, “second”, “one side”, “the other side” and the like are used to differentiate a certain component from other components, but the configuration of such components should not be construed to be limited by the terms. Further, in the description of the present invention, when it is determined that the detailed description of the related art would obscure the gist of the present invention, the description thereof will be omitted. 
         [0036]    Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.  FIG. 1  is a cross-sectional view showing a package according to a preferred embodiment of the present invention. 
         [0037]    A package according to a preferred embodiment of the present invention includes a plurality of pads  110  formed on a substrate  100 , solder resist patterns (SR patterns)  120  enclosing the pad  110  and burying another circuit pattern on the substrate  100 , solder patterns  210  formed to include a solder on each of the pads  110 , and a chip  200  connected to the pad  110  on the substrate  100  through the solder pattern  210  to be mounted thereon. 
         [0038]    The SR pattern  120  encloses a pad  110  region in which the chip  200  is mounted on the substrate  100  using the solder resist and buries a plurality of circuits formed in a region except for the pad  110  region. 
         [0039]    The solder pattern  210  is implemented as a form in which a conductive metal pattern  141 ′ is included in the solder and is formed between the pad  110  on the substrate  100  and the chip  200  to electrically connect therebetween. 
         [0040]    Specifically, the conductive metal pattern  141 ′, which is formed to support the form of the solder pattern  210 , is formed, for example, of a pattern in which a ball shape made of conductive metal materials such as copper, gold, silver, aluminum, or the like, is modified in a reflow process. 
         [0041]    Since each of the solder patterns  210  as described above has the same volume and is formed between the pad  110  and the chip  200 , the chip  200  is packaged while having the same mounted height T from an upper surface of the substrate  100 . 
         [0042]    Therefore, according to the package according to the preferred embodiment of the present invention, the chip  200  is packaged while having the same mounted height (T) from the upper surface of the substrate  100 , thereby making it possible to improve connection reliability between the chip  200  and the pad  110 . 
         [0043]    Hereinafter, a packaging method of a package according to a preferred embodiment of the present invention will be described with reference to  FIGS. 2A to 2F .  FIGS. 2A to 2F  are cross-sectional views sequentially showing the process of a packaging method of a package according to a preferred embodiment of the present invention. 
         [0044]    With the packaging method of the package according to the preferred embodiment of the present invention, a plurality of pads  110  and SR patterns  120  burying other circuit patterns are first formed on a substrate  100 , as shown in  FIG. 2A . 
         [0045]    Specifically, in order to form the plurality of pads  110  and another circuit patterns on the substrate  110 , a first dry film pattern having openings corresponding to the pad  110  and another circuit pattern is formed. 
         [0046]    Next, the first dry film pattern may be filled with copper by methods, for example, a chemical vapor deposition (CVD) method, a physical vapor deposition (PVD) method, a subtractive method, an additive method using an electroless copper plating or electrolytic copper plating, a semi-additive process (SAP), and a modified semi-additive process (MSAP). 
         [0047]    As such, the first dry film pattern is filled with the copper and then the dry film pattern is delaminated, such that the plurality of pads  110  and another circuit pattern are formed, as shown in  FIG. 2A . 
         [0048]    Subsequently, the SR pattern  120  burying another circuit pattern formed in the region except for the pad  110  region using the solder resist is formed. 
         [0049]    After the plurality of pads  110  and the SR pattern  120  burying another circuit pattern are formed on the substrate  100 , a second dry film pattern  130  exposing each of the pads  110  is formed, as shown in  FIG. 2B . 
         [0050]    Specifically, the second dry film pattern first laminates a dry film in an uncured state on the substrate  100  on which the plurality of pads  110  and the SR pattern  120  are formed, using a laminate. 
         [0051]    Next, the dry film laminated on the substrate  100  is subjected to a patterning process including a lithography process, an etching process, and the like, such that a second dry film pattern  130  having openings exposing each of the pads  110  may be formed. 
         [0052]    For the second dry film pattern  130  as described above, each of the openings exposing the pad  110  is mounted with a solder coating ball  140  having the same diameter, as shown in  FIG. 2C . 
         [0053]    Here, the solder coating ball  140  is formed of a metal ball  141  made of a conductive metal material and a solder coating film  142  formed on the outside of the metal ball  141 . The metal ball  141  is made of a conductive metal material, for example, copper, gold, silver, aluminum, or the like, and the solder coating film  142  is formed by plating the metal ball  141  as described above with the solder by a method such as electroplating, or the like. 
         [0054]    After the solder coating ball  140  is mounted, a reflow process is performed on the solder coating ball  140 , such that the metal ball  141  of the solder coating ball  140  is modified to have the conductive metal pattern  141 ′, as shown in  FIG. 2D . 
         [0055]    In this case, the solder coating film  142  formed on an outer surface of the metal ball  141  is melted and accumulated on a lower portion of the metal pattern  141 ′ to thereby be adhered to the pad  110 . 
         [0056]    Next, when the second dry film pattern  130  is delaminated, a structure having the same height t from the upper surface of the substrate  100  to the metal pattern  141 ′ is formed as shown in  FIG. 2E . 
         [0057]    Next, the chip  200  is mounted on the metal pattern  141 ′ having the same height t from the upper surface of the substrate  100  using the solder, as shown in  FIG. 2F . 
         [0058]    Therefore, a solder pattern  210  that the conductive metal pattern  141 ′ is included in the solder is formed and the plurality of solder patterns  210  as described above are formed between the pad  110  on the substrate  100  and the chip  200  to electrically connect therebetween. 
         [0059]    Since the solder pattern  210  as described above has the same volume and is formed between the pad  110  and the chip  200 , the chip  200  is packaged while having the same mounted height T from the upper surface of the substrate  100 . 
         [0060]    Therefore, according to the packaging method of the package according to the preferred embodiment of the present invention, the solder pattern  210  is easily formed using the solder coating ball  140 , thereby making it possible to reduce the manufacturing cost. 
         [0061]    In addition, according to the packaging method of the package according to the preferred embodiments of the present invention, the chip  200  is packaged while having the same mounted height ( 1 ) from the upper surface of the substrate  100 , thereby making it possible to improve the connection reliability between the chip  200  and the pad  110 . 
         [0062]    Hereinafter, a package according to another embodiment of the present invention will be described with reference to  FIG. 3 .  FIG. 3  is a cross-sectional view showing a package according to another preferred embodiment of the present invention. 
         [0063]    As shown in  FIG. 3 , a package according to another preferred embodiment of the present invention includes a plurality of pads  310  formed on a substrate  300 , a solder resist (SR) pattern layer  320  enclosing each of the pads  310  and a solder region thereon and burying another circuit pattern on the substrate  300 , solder patterns  350  including a conductive metal pattern  341 ′ on an upper surface of the SR pattern layer  320  and connected to a post bump  410 , and a chip  400  connected to the pad  310  on the substrate  300  through the solder pattern  350  and the post bump  410  to be mounted thereon. 
         [0064]    The SR pattern  320  encloses a region including each of the pads  310  and a solder of a top portion of the pad  310  on the substrate  300  using a solder resist and buries a plurality of circuits formed in another region. 
         [0065]    The solder pattern  350  in which a conductive metal pattern  341 ′ is included in the solder, electrically connects between the post bump  410  of the chip  400  and the pad  310 , while having a form in which the conductive metal pattern  341 ′ connected to the solder of the top portion of the pad  310  is included in an upper solder. 
         [0066]    Specifically, the conductive metal pattern  341 ′, which is formed to support the form of the solder pattern  350 , is formed of a pattern in which a ball shape made of metal materials, for example, copper, gold, silver, aluminum, or the like, is modified in a reflow process. 
         [0067]    Since each of the solder patterns  350  as described above has the same volume and is connected to the post bump  410 , the chip  400  is packaged while having the same mounted height T from an upper surface of the SR pattern layer  320 . 
         [0068]    Therefore, according to the package according to another preferred embodiment of the present invention, the chip  400  is packaged while having the same mounted height (T) from the upper surface of the SR pattern layer  320 , thereby making it possible to improve connection reliability between the chip  400  and the pad  310 . 
         [0069]    Hereinafter, a packaging method of a package according to another preferred embodiment of the present invention will be described with reference to  FIGS. 4A to 4G .  FIGS. 4A to 4G  are cross-sectional views sequentially showing the process of a packaging method of a package according to another preferred embodiment of the present invention. 
         [0070]    With the packaging method of the package according to another preferred embodiment of the present invention, the SR pattern layer  320  exposing upper surfaces of a plurality of pads  310  and burying other circuit patterns is formed on a substrate  300 , as shown in  FIG. 4A . 
         [0071]    Specifically, in order to form the plurality of pads  310  and another circuit patterns on the substrate  310 , a first dry film pattern having openings corresponding to the pad  310  and another circuit pattern is formed on an upper surface of the substrate  300 . 
         [0072]    Next, the first dry film pattern may be filled with copper by methods, for example, a chemical vapor deposition (CVD) method, a physical vapor deposition (PVD) method, a subtractive method, a additive method using an electroless copper plating or electrolytic copper plating, a semi-additive process (SAP), and a modified semi-additive process (MSAP). 
         [0073]    As such, the first dry film pattern is filled with the copper and then is delaminated, such that the plurality of pads  310  and another circuit pattern are formed on the substrate  300 , as shown in  FIG. 4A . 
         [0074]    The SR pattern layer  320  exposing the upper surface of the pad  310  and burying another circuit pattern may be formed by applying a solder resist to the substrate  300  including the plurality of pads  310  and another circuit pattern as described above and performing a patterning process including a lithography process and an etching processes on the applied solder resist. 
         [0075]    After the SR pattern layer  320  is formed, a second dry film pattern  330  exposing each of the upper surfaces of the pad  310  is formed on an upper surface of the SR pattern layer  320 , as shown in  FIG. 4B . 
         [0076]    Specifically, for the second dry film pattern, a dry film in an uncured state is first laminated on the SR pattern  320  using a laminate. 
         [0077]    Next, the laminated dry film is subjected to a patterning process including a lithography process, an etching process, a cleaning process, and the like, such that the second dry film pattern  330  having openings exposing the upper surface of each of the pads  310  may be formed. 
         [0078]    For the second dry film pattern  330  as described above, each of the openings exposing the upper surface of the pad  310  is mounted with a solder coating ball  340  having the same diameter, as shown in  FIG. 4C . 
         [0079]    The solder coating ball  340  is formed of a metal ball  341  made of a conductive metal material and a solder coating film  342  formed on the outside of the metal ball  341 . The metal ball  341  is made of the conductive metal material, for example, copper, gold, silver, aluminum, or the like, and the solder coating film  342  is formed by plating the metal ball  341  with the solder by a method such as electroplating, or the like. 
         [0080]    After the solder coating ball  340  is mounted, a reflow process is performed on the solder coating ball  340 , such that the metal ball  340  of the solder coating ball  341  is modified to have the conductive metal pattern  341 ′, as shown in  FIG. 4D . 
         [0081]    In this case, the solder coating film  342  formed on an outer surface of the metal ball  341  is melted and accumulated on a lower portion of the metal pattern  341 ′ as the solder to thereby be adhered to the pad  310 . 
         [0082]    Next, the solder is injected into the openings of the second dry film pattern  330  each provided with the metal pattern  341 ′ using a solder injector  500 . 
         [0083]    As such, as the solder is injected into the openings using the solder injector  500 , a solder pattern  350  in which the metal pattern  341 ′ is buried by the solder may be formed. 
         [0084]    Here, the solder injector  500  includes a storing part  510  storing the solder supplied from the outside, a discharging hole  511  connected to the storing part  510  in the form of a pipe to discharge the solder, a heating part  512  enclosing and heating the discharging hole  511 , and a press-fitting part  520  allowing a melted solder discharged from the discharging hole  511  to flow a surface to be injected. 
         [0085]    The storing part  510  stores the solder supplied from the outside and includes a pressurization pump or a piston, thereby discharging the solder into the discharging hole  511 . Here, the storing part  510  is supplied with the solder in the form of a solder paste and stores a flux or the like in addition to the solder, thereby discharging them into the discharging hole  511 . 
         [0086]    The heating part  512  is formed of a heat wire or a heater enclosing a circumference of the discharging hole  511 , and heats and melts the solder discharged along with the discharging hole  511 . 
         [0087]    The press-fitting part  520  is a part contacting and squeegeeing the upper surface of the second dry film pattern  330  and the melted solder discharged from an end of the discharging hole  511  flows down along with a surface of the press-fitting part  520 . The press-fitting part  520  is formed of an elastic material, such that the melted solder discharged from the end of the discharging hole  511  flows to be filled and press-fitted in the openings of the second dry film pattern  330 . 
         [0088]    Due to the press-fitting part  520 , the solder pattern  350  in which the metal pattern  341 ′ is buried may be formed to have a flat upper surface. 
         [0089]    Next, when the solder pattern  350  is cured and then the second dry film pattern  330  is delaminated, the solder pattern  350  having the same height t from the upper surface of the substrate  300  is formed as shown in  FIG. 4F . 
         [0090]    The solder pattern  350  is connected to a post bump  410 , such that a chip  400  is mounted so as to be electrically connected to the pad  310  on the substrate  300 . Of course, the chip  400  may also be mounted to be electrically connected to the pad  310  on the substrate  300  only using the solder pattern  350 , without the post bump  410 . 
         [0091]    Therefore, the chip  400  is packaged while having the same mounted height from the upper surface of the SR pattern layer  320 , thereby making it possible to improve connection reliability between the chip  400  and the pad  310 . 
         [0092]    According to the package according to the preferred embodiment of the present invention, the chip is packaged while having the same mounted height (T) from the upper surface of the substrate, thereby making it possible to improve the connection reliability between the chip and the pad. 
         [0093]    According to the packaging method according to another preferred embodiment of the present invention, the solder pattern is easily formed using the solder coating ball, thereby making it possible to reduce the manufacturing cost. 
         [0094]    Although the embodiments of the present invention have been disclosed for illustrative purposes, it will be appreciated that the present invention is not limited thereto, and those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention. 
         [0095]    Accordingly, any and all modifications, variations or equivalent arrangements should be considered to be within the scope of the invention, and the detailed scope of the invention will be disclosed by the accompanying claims.