Abstract:
A method of forming an external electrode of an electronic component involves a paste preparation step, a removal step, an element preparation step, a contact step, and a formation step. The first step is to prepare a jig with a groove into which an element forming the electronic component can be inserted. The groove of the jig includes at least a first wall surface inclined outward in a direction from an interior toward an aperture. The paste preparation step is to fill a conductive paste in the groove. The removal step is to remove the filled conductive paste so as to leave the conductive paste along the first wall surface and remove the rest. The ealement preparation step is to locate the element immediately above the groove. The contact step is to insert the element into the groove and to move the element toward the first wall surface to bring a ridgeline of the element into contact with the first wall surface. The formation step is to move the element along the first wall surface and toward the aperture in a state in which the ridgeline of the element is kept in contact with the first wall surface, and to move the element away from the first wall surface so as to separate the ridgeline from the first wall surface.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a method of forming an external electrode of an electronic component. 
         [0003]    2. Related Background Art 
         [0004]    With downsizing of electronic devices and others in recent years, electronic components used therein are also being downsized. Downsizing is particularly significant for surface-mounted electronic components by virtue of improvement in mount technology. External electrodes for mounting on a substrate need to be formed on these electronic components, and a plurality of external electrodes are sometimes formed on side and end faces of a component according to need. There are a variety of proposals on methods of forming the external electrodes. 
         [0005]    One of the methods of forming the external electrodes of the electronic components is the method described in U.S. Pat. No. 5,753,299. This method is to form external electrodes on an end face of a chip being an element to become an electronic component, and on side faces adjacent to the end face. More specifically, consecutively projecting portions called fingers of a comb-shaped plate are arranged at positions opposite to the end face of the chip, and a conductive paste for formation of external electrodes is applied onto tips of the fingers. Subsequently, the fingers are brought into contact with the chip and are slid in directions perpendicular to the extending direction of the chip to rub the conductive paste onto the chip, thereby forming external electrodes. 
       SUMMARY OF THE INVENTION 
       [0006]    When the external electrodes are formed by rubbing the conductive paste onto the end face of the chip as described above, the external electrodes formed on the side faces are formed by downward flows of the conductive paste. More specifically, the conductive paste scraped off by a ridgeline between the end face and each side face flows down the side face of the chip to form the external electrodes on the side face. For this reason, shapes of the external electrodes formed on the side face of the chip are affected by the viscosity of the conductive paste or the like. However, it is difficult to freely control the viscosity of the conductive paste and it is thus difficult to control the lengths of the external electrodes from the ridgeline on each side face of the chip by adjustment of the viscosity of the conductive paste. 
         [0007]    Then the Inventors conducted research from a variety of viewpoints on how to control the length of the external electrode by methods other than the adjustment of viscosity of the conductive paste. As an initial step of the research, the Inventors investigated whether the length of the external electrode could be controlled by adjusting an amount of the conductive paste scraped off by the ridgeline between the end face and the side face of the chip. From this investigation, the Inventors found that an increase in the amount of the conductive paste increased the length of an extension of the external electrode on the side face of the chip in the direction away from the ridgeline and along the side face, but also inevitably increased the width of an extension in the direction along the ridgeline. It is seen from this expertise that a sufficient distance is not always assured between adjacent external electrodes and that it could result in a short circuit between the electrodes. 
         [0008]    In the next step of the investigation, the Inventors found that a decrease in the amount of the conductive paste for assuring the distance between adjacent external electrodes resulted in decreasing the downward flow amount and restricting the extension length in the direction away from the ridgeline of the external electrode and that it could result in failing to assure a sufficient area of the external electrode. After further research, the Inventors discovered that when the external electrode was formed by scraping off the conductive paste by the ridgeline as described, the state of the external electrode on the side face was affected by the level of the downward flow of the conductive paste, the shape thereof was sometimes unstable, and, when the chip was mounted on a substrate, it could cause the Manhattan phenomenon. 
         [0009]    An object of the present invention is therefore to provide a method of forming an external electrode of an electronic component, by which the external electrode can be formed on a stable basis. 
         [0010]    An external electrode forming method according to the present invention is a method of forming an external electrode of an electronic component, comprising: a step of preparing a jig with a groove in which an element forming the electronic component can be inserted, wherein the groove includes at least a first wall surface inclined outward in a direction from an interior toward an aperture; a paste preparation step of filling a conductive paste in the groove; a removal step of removing the filled conductive paste so as to leave the conductive paste at least along the first wall surface and remove the rest; an element preparation step of locating the element immediately above the groove; a contact step of inserting the element into the groove and moving the element toward the first wall surface to bring a ridgeline of the element into contact with the first wall surface; and a formation step of moving the element in a state of the contact along the first wall surface of the groove and toward the aperture and moving the element away from the first wall surface so as to separate the ridgeline at least from the first wall surface. 
         [0011]    According to the present invention, the element is moved toward the first wall surface to bring a ridgeline of the element into contact with the first wall surface; therefore, an angle of contact between one face of the element and the first wall surface is acute. Then the element in the contact state is moved along the first wall surface of the groove and toward the aperture, whereby an electrode portion can be stably formed in an intended shape. Particularly, by controlling a moving distance of the element along the first wall surface and toward the aperture in the state in which the element is in contact with the first wall surface, the length of the electrode portion formed on one face of the element can be controlled in the direction away from the ridgeline. 
         [0012]    In the present invention, the element is moved along the first wall surface of the groove and toward the aperture in the state in which the element is in contact with the first wall surface, and the element is moved away from the first wall surface so as to separate the ridgeline at least from the first wall surface. This results in applying a sufficient amount of the conductive paste along the ridgeline. Therefore, the external electrode can be stably formed in an intended thickness. Particularly, a sufficient thickness can be secured at a corner of the element. 
         [0013]    Preferably, the method comprises an inclining step of further moving the element toward the first wall surface to incline the element so as to follow the first wall surface, after the contact step. 
         [0014]    By this step, the element is inclined so as to follow the first wall surface, and thus the angle of contact between one face of the element and the first wall surface becomes acuter. Therefore, an electrode portion can be stably formed in an intended shape on the one face. Particularly, by controlling the angle of contact between the one face of the element and the first wall surface, the length of the electrode portion formed on the one face of the element can be controlled in the direction away from the ridgeline. 
         [0015]    Another external electrode forming method of the present invention is a method of forming external electrodes of an electronic component, comprising: a step of preparing a jig in which a plurality of platelike members, each being provided with a groove into which an element forming the electronic component can be inserted, are arranged along each other, wherein each of the grooves includes at least a first wall surface inclined outward in a direction from an interior toward an aperture; a preparation step of filling a conductive paste in each of the grooves so as to cover across the grooves of the respective platelike members; a removal step of removing the conductive paste existing between the platelike members and thereby leaving the conductive paste in each of the grooves, at least along the first wall surface of each groove; an element preparation step of locating the element forming the electronic component, immediately above the grooves; a contact step of inserting the element into the grooves so as to extend across the grooves, and moving the element toward the first wall surfaces of the respective grooves to bring a ridgeline of the element into contact with the first wall surfaces; and a formation step of moving the element in a state of the contact along the first wall surfaces of the respective grooves and toward the aperture and moving the element away from the first wall surfaces so as to separate the ridgeline at least from the first wall surfaces of the respective grooves. 
         [0016]    According to the present invention, the conductive paste is filled in the grooves of the platelike members arranged along each other, and the conductive paste present between the platelike members is then removed, whereby the excess conductive paste filled in the grooves flows out. Therefore, the conductive paste can be left along the wall surfaces of the respective grooves of the platelike members. 
         [0017]    Since the element is moved toward the first wall surfaces to bring a ridgeline of the element into contact with the first wall surfaces of the respective grooves, the angles of contact between one face of the element and the first wall surfaces are acute. Then the element in the contact state is moved along the first wall surfaces of the respective grooves and toward the aperture, whereby electrode portions can be stably formed in an intended shape and at a plurality of locations on the one face. Particularly, by controlling a moving distance of the element along the first wall surfaces of the grooves and toward the aperture in the state in which the element is in contact with the first wall surfaces, the length of the electrode portions formed alongside at a plurality of locations on the one face of the element can be controlled in the direction away from the ridgeline. 
         [0018]    Since the element is moved away from the first wall surfaces so as to separate the ridgeline at least from the first wall surfaces of the respective grooves, sufficient amounts of the conductive paste are applied along the ridgeline. Therefore, the external electrodes can be stably formed in an intended thickness. Particularly, a sufficient thickness can be secured at a corner of the element. 
         [0019]    The present invention enables stable formation of the external electrode in intended shape and thickness. 
         [0020]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present invention. 
         [0021]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a drawing showing an outline of an external electrode forming method as a first embodiment of the present invention. 
           [0023]      FIG. 2  is a drawing showing the external electrode forming method as the first embodiment of the present invention. 
           [0024]      FIGS. 3 to 7  are views for explaining the external electrode forming method as the first embodiment of the present invention. 
           [0025]      FIGS. 8 to 10  are views for explaining an external electrode forming method as a second embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    The expertise of the invention can be readily understood in view of the following detailed description with reference to the accompanying drawings presented by way of illustration only. Subsequently, embodiments of the present invention will be described with reference to the accompanying drawings. The same portions will be denoted by the same reference symbols as much as possible, without redundant description. 
       First Embodiment 
       [0027]    An external electrode forming method, which is the first embodiment of the present invention, will be described below. The external electrode forming method of the present embodiment is outlined as follows: as shown in  FIG. 1 , an application bed  10  (jig) with a groove  101  of a V-shaped cross section (a groove with wall surfaces inclined outward in the direction from the interior toward the aperture) is prepared, and a conductive paste  20  is attached so as to lie along the wall surfaces of the groove  101 . After that, chips  30  (elements) are inserted into the groove  101 , the chips  30  are brought into contact with a wall surface, and the chips are moved along a direction of an arrow in the drawing. The chips  30  are further moved away from the wall surface to form an external electrode  301  on a side face of each chip  30 . Subsequently, the external electrode forming method will be detailed below. 
         [0028]      FIG. 2  is a drawing for explaining the procedure of the external electrode forming method of the present embodiment.  FIGS. 3 to 7  are views of chip  30  and application bed  10  from the direction along the groove  101 , and views showing states of respective steps in the external electrode forming method. The method will be described along the flow shown in  FIG. 2  and with reference to  FIGS. 3 to 7  on an as-needed basis. 
         [0029]    The application bed  10  (jig) with the groove  101  of the V-shaped cross section is prepared and the conductive paste  20  is filled in the groove  101  and on a principal surface  102  of the application bed  10  (step S 01  in  FIG. 2 , (A) in  FIG. 3 , preparation step). 
         [0030]    Subsequently, a blade  40  is used to scrape out the conductive paste in the groove  101  and on the principal surface  102  (step S 02  in  FIG. 2 , (B) in  FIG. 3 , removal step). As shown in (B) in  FIG. 3 , the blade  40  has a projection that can be put in the groove  101 , and the blade  40  is arranged so that a certain clearance is made relative to the groove  101  and principal surface  102 . Therefore, as shown in (C) in  FIG. 3 , the conductive paste  20  is left along wall surfaces  101   a ,  101   b  of the groove  101  and along the principal surface  102 , and the rest is removed. 
         [0031]    Subsequently, a chip  30  is located immediately above the groove  101  (step S 03  in  FIG. 2 , (A) in  FIG. 4 , element preparation step). At this time, the chip  30  is located so that an extension of a center line L of the chip  30  coincides with a bottom  101   c  of the groove of the V-shaped cross section. The chip  30  is held as pasted to an adhesive tape  51  provided on a holding plate  50 . P Next, the holding plate  50  is moved vertically downward to a position where the tip of the chip  30  is located in the groove  101  ((B) in  FIG. 4 ). Subsequently, relative movement is effected between the holding plate  50  and the application bed  10  so as to bring a side face  30   a  of the chip  30  closer to the wall surface  101   a  of the groove  101  (step S 04  in  FIG. 2 , (C) in  FIG. 4 , contact step). This relative movement between the holding plate  50  and the application bed  10  results in bringing a ridgeline  30   d  between the side face  30   a  and an end face  30   c  of the chip  30  into contact with the wall surface  101   a  of the groove  101 . At this time, the angle of contact between the side face  30   a  of the chip  30  and the wall surface  101   a  of the groove  101  is acute. 
         [0032]    Further relative movement between the holding plate  50  and the application bed  10  results in bringing the chip  30  into a further inclined state toward the wall surface  101  a of the groove  101  as shown in (A) in  FIG. 5 . This makes the contact angle acuter, whereby an electrode portion can extend in the direction away from the ridgeline and can be stably formed in an intended shape on the side face  30   a  of the chip  30 . By controlling the contact angle, the length of the electrode portion formed on the side face  30   a  of the chip  30  can be controlled in the direction away from the ridgeline. 
         [0033]    From the state of (A) in  FIG. 5 , the chip  30  is moved along the wall surface  101   a  of the groove  101  and toward the aperture of the groove  101 , to scrape off the conductive paste  20  attached to the application bed  10  ((B) in  FIG. 5 ). By controlling a distance of movement of the chip  30 , the length of the electrode portion formed on the side face  30   a  of the chip  30  can be controlled in the direction away from the ridgeline. 
         [0034]    Furthermore, the chip  30  is moved away from the wall surface  101   a  of the groove  101  so as to separate the ridgeline  30   d  between the side face  30   a  and the end face  30   c  of the chip  30  from the wall surface  101   a  of the groove  101  (step S 05  in  FIG. 2 , (D) in  FIG. 5 , formation step). This results in forming an electrode portion  301   a  on the side face  30   a  and ridgeline  30   d  of the chip  30 . Since the conductive paste is separated so as to thread in the process of moving the ridgeline  30   d  between the side face  30   a  and the end face  30   c  of the chip  30  away from the wall surface  101   a  of the groove  101  ((C) in  FIG. 5 ), a sufficient amount of the conductive paste is applied along the ridgeline  30   d . Therefore, a sufficient thickness can be secured at the corner of the element. 
         [0035]    Subsequently, an electrode portion is formed on another side face  30   b  opposite to the side face  30   a  of the chip  30 . Since this step is similar to the forming method of the electrode portion  301   a , description thereof with reference to drawings is omitted herein. The chip  30  is moved to a position similar to that in (A) in  FIG. 4 , i.e., to immediately above the groove  101 , and then the holding plate  50  is moved vertically downward to a position similar to that in (B) in  FIG. 4 , i.e., to a position where the tip of the chip  30  is located in the groove  101 . 
         [0036]    Subsequently, relative movement is effected between the holding plate  50  and the application bed  10  to bring the side face  30   b  of the chip  30  closer to the wall surface  101   b  of the groove  101  (step S 06  in  FIG. 2 ). This relative movement between the holding plate  50  and the application bed  10  results in bringing a ridgeline  30   e  between the side face  30   b  and the end face  30   c  of the chip  30  into contact with the wall surface  101   b  of the groove  101 . At this time, the angle of contact between the side face  30   b  of the chip  30  and the wall surface  101   b  of the groove  101  is acute. 
         [0037]    Further relative movement between the holding plate  50  and the application bed  10  brings the chip  30  into a further inclined state toward the wall surface  101   b  of the groove  101 . Since this makes the contact angle acuter, an electrode portion can extend in the direction away from the ridgeline and can be stably formed in an intended shape on the side face  30   b  of the chip  30 . By controlling the contact angle, the length of the electrode portion formed on the side face  30   b  of the chip  30  can be controlled in the direction away from the ridgeline. 
         [0038]    From the state in which the chip  30  is further inclined toward the wall surface  101   b  of the groove  101 , the chip  30  is moved along the wall surface  101   b  of the groove  101  and toward the aperture of the groove  101  to scrape off the conductive paste  20  attached to the application bed  10 . By controlling a distance of movement of the chip  30 , the length of the electrode portion formed on the side face  30   b  of the chip  30  can be controlled in the direction away from the ridgeline. 
         [0039]    Furthermore, the chip  30  is moved away from the wall surface  101   b  of the groove  101  so as to separate the ridgeline  30   e  between the side face  30   b  and the end face  30   c  of the chip  30  from the wall surface  101   b  of the groove  101 . This results in forming the electrode portion  301   b  on the side face  30   b  and ridgeline  30   e  of the chip  30  (step S 07  in  FIG. 2 ). 
         [0040]    Subsequently, relative movement is effected between the holding plate  50  and the application bed  10  so as to locate the chip  30  above the principal surface  102  of the application bed  10  ((A) in  FIG. 6 ). From that position, the holding plate  50  is moved toward the application bed  10  so as to bring the end face  30   c  of the chip  30  into contact with the principal surface  102  ((B) in  FIG. 6 ). When the end face  30   c  of the chip  30  is brought into contact with the principal surface  102 , an electrode portion  301   c  is formed to connect between the electrode portion  301   a  and the electrode portion  301   b  (step S 08  in  FIG. 2 ). 
         [0041]    Subsequently, the holding plate  50  is moved away from the application bed  10 , and the chip  30  is dried, whereby an external electrode  301  is formed in a configuration in which the electrode portion  301   a , the electrode portion  301   b , and the electrode portion  301   c  connect with each other ((C) in  FIG. 6 ). 
         [0042]    Subsequently, a blade  45  is used to scrape out the conductive paste in the groove  101  and on the principal surface  102  (step S 09  in  FIG. 2 , (D) in  FIG. 6 ). As shown in (D) in  FIG. 6 , the blade  45  is so convex as to be fitted in the groove  101 . The blade  45  is different from the blade  40  shown in (B) in  FIG. 3 , in that no clearance is made between the blade  45  and the groove  101  and principal surface  102 . Therefore, as shown in (E) in  FIG. 6 , the conductive paste is completely scraped out from in the groove  101  and on the principal surface  102 . 
         [0043]    In the present embodiment, as described above, each of the side faces  30   a ,  30   b  of the chip  30  is moved toward the wall surface  101   a  or  101   b  of the groove  101  opposed to the face, to bring each of the ridgelines  30   d ,  30   e  of the chip  30  into contact with the corresponding wall surface  101   a ,  101   b  of the groove  101 . This makes the angle of contact acute between the side face  30   a  of the chip  30  and the wall surface  101   a  of the groove  101  or between the side face  30   b  of the chip  30  and the wall surface  101   b  of the groove  101 . Then each of the ridgelines  30   d ,  30   e  of the chip  30  is moved along the wall surface  101   a ,  101   b  and toward the aperture in the state in which it is in contact with the wall surface  101   a ,  101   b  of the groove  101 . This permits the electrode portion to be stably formed in the intended shape. 
         [0044]    After the contact step, further relative movement is effected between the holding plate  50  and the application bed  10  to control the angle of contact between the side face  30   a  of the chip  30  and the wall surface  101   a  of the groove  101  or between the side face  30   b  of the chip  30  and the wall surface  101   b  of the groove  101 . The method is also arranged to control the moving distance of each of the ridgelines  30   d ,  30   e  of the chip  30  along the wall surface  101   a ,  101   b  and toward the aperture in the state in which the ridgeline is kept in contact with the wall surface  101   a ,  101   b  of the groove  101 . These permit us to control the lengths of the electrode portions formed on the side face  30   a  and on the side face  30   b  of the chip  30 , in the direction away from the ridgeline. 
         [0045]    Each of the ridgelines  30   d ,  30   e  of the chip  30  is moved along the wall surface  101   a ,  101   b  and toward the aperture in the state in which it is kept in contact with the wall surface  101   a ,  101   b  of the groove  101 , and the chip  30  is moved away from the wall surface  101   a ,  101   b  of the groove  101  so as to separate the ridgeline  30   d ,  30   e  of the chip  30  from the wall surface  101   a ,  101   b  of the groove  101 . This results in applying a sufficient amount of the conductive paste along the ridgeline  30   d ,  30   e  of the chip  30 . Therefore, the external electrode can be stably formed in an intended thickness. Particularly, a sufficient thickness can be secured at each corner of the chip  30 . 
         [0046]    In a case of an operation in which a plurality of chips  30  are aligned along the groove  101 , each of the chips  30  can be appropriately brought into contact with the wall surface  101   a  of the groove  101 . In a case where some chips  30 ′ are placed a little apart from the predetermined position (the position of chip  30 ) in the element preparation step as shown in  FIG. 7  (A), there appears only a small difference of contact angle between the side faces  30   a  and  30 ′ a  of the respective chips  30  and  30 ′ and the wall surface  101   a  of the groove  101  in the contact step, as shown in  FIG. 7  (B). Therefore, the same amount of the conductive paste is applied onto the side faces of the respective chips, and the external electrode can be stably formed in the intended shape on each of the chips. 
       Second Embodiment 
       [0047]    Another external electrode forming method, which is the second embodiment of the present invention, will be described below. The external electrode forming method of the present embodiment is a method for simultaneously forming a plurality of external electrodes on a chip. The second embodiment is different mainly in the used jigs, such as the application bed and blades, from the first embodiment.  FIGS. 8 to 10  are views for explaining the procedure of the external electrode forming method of the present embodiment. The external electrode forming method of the present embodiment will be described with reference to  FIGS. 8 to 10 . 
         [0048]    First, an application bed  6  and a blade  7  are prepared ((A) in  FIG. 8 ). The application bed  6  is comprised of a base  60  and four platelike members  61 . The platelike members  61  are attached to the base  60  so that they are parallel to each other at intervals. Grooves  611  of a V-shaped cross section are formed at the same position in the respective platelike members  61 . 
         [0049]    The blade  7  is comprised of a base  70  and a scraper  71 . Teeth  711  are formed in the scraper  71 . The teeth  711  are formed so that they can be put into between the platelike members  61  of the application bed  6 . 
         [0050]    Subsequently, the conductive paste  8  is delivered so as to cover across the grooves  611  of the V-shaped cross section in the respective platelike members  61  of the application bed  6  ((B) in  FIG. 8 ). Therefore, the conductive paste  8  is filled in the grooves  611  of the V-shaped cross section in the respective platelike members  61  (preparation step). 
         [0051]    Subsequently, relative movement is effected between the blade  7  and the application bed  6  so as to bring the blade  7  into contact with the application bed  6  ((A) in  FIG. 9 ). This movement results in inserting each of the teeth  711  of the blade  7  into between the platelike members  61  of the application bed  6 . The blade  7  and the application bed  6  are formed so that a clearance is made between the upper ends of the platelike members  61  and the roots located between the teeth  711 , in a state in which the tips of the teeth  711  are in contact with the base  60  of the application bed  6 . Therefore, the conductive paste  8  is pushed out through the clearance onto the platelike members  61 . 
         [0052]    Subsequently, the blade  7  is moved along the platelike members  61  to scrape out the conductive paste  8  present between the platelike members  61  ((B) in  FIG. 9 , removal step). Since the conductive paste  8  is fluid, the conductive paste  8  remaining in the grooves  611  of the V-shaped cross section in the platelike members  61  flows out into between the platelike members  61  ((C) in  FIG. 9 ). Therefore, the conductive paste  8  is left along the grooves  611  of the V-shaped cross section in the platelike members  61 . 
         [0053]    Subsequently, a chip  90  is located across the grooves  611  of the V-shaped cross section in the respective platelike members  61  and immediately above the grooves  611  of the V-shaped cross section ((A) in  FIG. 10 , element preparation step). The chip  90  is held as pasted to an adhesive tape (not shown) provided on a holding plate (not shown) as in the first embodiment. 
         [0054]    Subsequently, the holding plate is moved vertically downward to locate the chip  90  at a position where the tip thereof is inserted in the grooves  611  of the V-shaped cross section. Subsequently, relative movement is effected between the holding plate and the application bed  6  so as to bring a side face  90   a  of the chip  90  closer to wall surfaces  611   a  of the respective grooves  611  of the V-shaped cross section (contact step). This results in bringing a ridgeline  90   d  between the side face  90   a  and an end face  90   c  of the chip  90  into contact with the wall surfaces  611   a  of the respective grooves  611 . At this time, angles of contact between the side face  90   a  of the chip  90  and the wall surfaces  611   a  of the respective grooves  611  are acute. As in the first embodiment, further relative movement may be effected between the holding plate and the application bed  6 . By controlling the angles of contact, the length of the electrode portions formed on the side face  90   a  of the chip  90  can be controlled in the direction away from the ridgeline. 
         [0055]    Subsequently, from the state in which the ridgeline  90   d  between the side face  90   a  and the end face  90   c  of the chip  90  is in contact with the wall surfaces  611   a  of the respective grooves  611 , the chip  90  is moved along the wall surfaces  611   a  of the grooves  611  and toward the aperture side of the grooves  611  to scrape off the conductive paste  8  attached to the application bed  6 . By controlling a distance of movement of the chip  90 , the length of electrode portions formed on the side face  90   a  of the chip  90  can be controlled in the direction away from the ridgeline. 
         [0056]    Furthermore, the chip  90  is moved away from the wall surfaces  611   a  so as to separate the ridgeline  90   d  between the side face  90   a  and the end face  90   c  of the chip  90  from the wall surfaces  611   a  of the grooves  611  (formation step). This results in forming electrode portions on the side face  90   a  and the ridgeline  90   d  of the chip  90 . 
         [0057]    Subsequently, the chip  90  is located across the grooves  611  of the V-shaped cross section in the respective platelike members  61  and immediately above the grooves  611  of the V-shaped cross section. Subsequently, the holding plate is moved vertically downward to locate the chip  90  at a position where the tip thereof is inserted in the grooves  611  of the V-shaped cross section. 
         [0058]    Subsequently, relative movement is effected between the holding plate and the application bed  6  so as to bring another side face  90   b  of the chip  90  closer to wall surfaces  611   b  of the grooves  611  of the V-shaped cross section (contact step). This results in bringing a ridgeline  90   e  between the side face  90   b  and the end face  90   c  of the chip  90  into contact with the wall surfaces  611   b  of the respective grooves  611 . At this time, angles of contact between the side face  90   b  of the chip  90  and the wall surfaces  611   b  of the respective grooves  611  are acute. As in the first embodiment, further relative movement may be effected between the holding plate and the application bed  6 . By controlling the contact angles, the length of electrode portions formed on the side face  90   b  of the chip  90  can be controlled in the direction away from the ridgeline. 
         [0059]    Subsequently, from the state in which the ridgeline  90   e  between the side face  90   b  and the end face  90   c  of the chip  90  is in contact with the wall surfaces  611   b  of the respective grooves  611 , the chip  90  is moved along the wall surfaces  611   b  of the grooves  611  and toward the aperture side of the grooves  611  to scrape off the conductive paste  8  attached to the application bed  6 . Furthermore, the chip  90  is moved to a position where the ridgeline  90   e  between the side face  90   b  and the end face  90   c  of the chip  90  is separated from the wall surfaces  611   b  of the grooves  611  (formation step). This results in forming the electrode portions  901   b  on the side face  90   b  and the ridgeline  90   e  of the chip  90 . 
         [0060]    Subsequently, relative movement is effected between the chip  90  and the application bed so as to locate the chip  90  above portions except for the grooves  611  of the platelike members  61 . After that, relative movement is effected between the chip  90  and the application bed  6  so as to bring the chip  90  into contact with the portions except for the grooves  611  of the platelike members  61 . When the tip of the chip  90  is brought into contact with the portions except for the grooves  611  of the platelike members  61 , electrode portions are formed so as to connect between the electrode portions  901   a  and the electrode portions  901   b.    
         [0061]    Subsequently, the chip  90  is moved away from the application bed  6  and the chip  90  is dried, whereby the external electrodes are formed each in a configuration in which the electrode portion  901   a , the electrode portion  901   b , and the electrode portion  901   c  between the electrode portions  901   a  and  901   b  connect with each other ((B) in  FIG. 10 ). 
         [0062]    In the present embodiment, as described above, each of the side faces  90   a ,  90   b  of the chip  90  is moved toward the wall surfaces  611   a  or wall surfaces  611   b  of the respective grooves  611  facing the side face, to bring each of the ridgelines  90   d ,  90   e  of the chip  90  into contact with the wall surfaces  611   a  or  611   b  of the respective grooves  611 . This makes the angles of contact acute between the side face  90   a  of the chip  90  and the wall surfaces  611   a  of the grooves  611  or between the side face  90   b  of the chip  90  and the wall surfaces  611   b  of the grooves  611 . Since each of the ridgelines  90   d ,  90   e  of the chip  90  is moved along the wall surfaces  611   a  or  611   b  and toward the aperture side in the state in which it is kept in contact with the wall surfaces  611   a  or  611   b  of the grooves  611 , the electrode portions can be stably formed in the intended shape. After the electrode portions  901   a  and the electrode portions  901   b  are formed, the electrode portions are formed so as to connect between them, and thus the electrode portions can be stably formed. 
         [0063]    The method is arranged to control the moving distance of each of the ridgelines  90   d ,  90   e  of the chip  90  along the wall surfaces  611   a  or  611   b  and toward the aperture side in the state in which it is kept in contact with the wall surfaces  611   a  or  611   b  of the grooves  611 . This permits us to control the length of the electrode portions formed on the side face  90   a  and on the side face  90   b  of the chip  90  in the direction away from the ridgeline. 
         [0064]    In the present embodiment, the electrode portions  901   a  and electrode portions  901   b  are formed alongside at a plurality of locations so as to correspond to each other, and the electrode portions are formed so as to connect between the corresponding electrode portions  901   a  and electrode portions  901   b . This permits us to form the stable external electrodes efficiently. 
         [0065]    In the present embodiment, the conductive paste  8  is filled in the grooves  611  of the platelike members  61  arranged along each other, and the conductive paste  8  present between the platelike members  61  is then removed. This causes the excess conductive paste  8  filled in the grooves  611  to flow out. Therefore, the conductive paste  8  can be left along the wall surfaces of the grooves  611  of the respective platelike members  61 . 
         [0066]    The first and second embodiments were described above using the groove of the V-shaped cross section, as an example of the groove with the wall surfaces inclined outward in the direction from the interior toward the aperture. Without having to be limited to this example, the groove may be any groove with wall surfaces inclined outward at least in the direction from the interior toward the aperture. For example, the groove may be one of a trapezoidal cross section. 
         [0067]    From the invention thus described, it will be obvious that the invention may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended for inclusion within the scope of the following claims.