Abstract:
The present invention provides a system and method suitable for inspecting a semiconductor device whose terminals are formed from solder balls and protrude from a package, thus enabling high-speed inspection of a semiconductor device having a plurality of pins. Metal protuberances corresponding to respective terminals projecting from the bottom of a package of a semiconductor device are provided on an interface substrate. Contact sections corresponding to the respective metal protuberances are provided within each of a plurality of slide sections. The semiconductor device is set on the slide section such that the terminals are disposed opposite the respective metal protuberances. The slide sections are slid over the interface substrate, thereby bringing the side surfaces of the terminals of the semiconductor device into contact with the contact sections. Each of the contact sections is formed from a conductive contact plate, a elastic film, and a slide guide having rigidity.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a system and method for inspecting a semiconductor device, and more particularly, to a system and method suitable for inspecting a semiconductor device whose terminals are formed from solder balls and protrude from a package.  
           [0003]    2. Description of the Background Art  
           [0004]    [0004]FIGS. 9 and 10 show inspection sockets which have conventionally been used for inspecting a semiconductor device of ball grid array (BGA) type or a semiconductor device of chip-size package (CSP) type. In FIGS. 9 and 10, reference numeral  10  designates the bottom of a package of a semiconductor device which is an object of inspection. Further, reference numeral  12  designates a solder ball provided as a terminal on the bottom  10  of the package.  
           [0005]    An inspection socket  14  shown in FIG. 9 is of leaf spring type. A leaf spring  16  is provided on an interface substrate (simply called IF substrate)  15 . Further, the inspection socket  14  is provided with a slide guide for adjusting the position of the leaf spring  16 . The leaf spring  16  clamps the solder ball  12  from both sides thereof by means of elastic force of the leaf spring  16 , thus achieving desired contact.  
           [0006]    An inspection socket  17  shown in FIG. 10 is of POGO type, and has an extendable POGO pin  18  provided on the IF substrate  15 . A semiconductor device is set on the IF substrate  15  such that each of the POGO pins  18  comes into contact with the corresponding solder ball  12 , whereby the inspection socket  17  of this type can achieve desired contact.  
           [0007]    In the case of the inspection socket  14  of leaf spring type shown in FIG. 9, the leaf spring  14  must provide sufficient elastic force. Therefore, a comparatively long distance; particularly, a distance of about  10  mm, must be ensured between the IF substrate  15  and the solder ball  12 . Inductance arising between the IF substrate  15  and the solder ball  12  increases with the distance therebetween. A signal exchanged between the IF substrate  15  and the solder ball  12  is degraded in, particularly, a high-frequency range, as inductance existing between the IF substrate  15  and the solder ball  12  becomes greater. For this reason, the inspection socket  14  of leaf spring type is not suitable for high-speed testing of a semiconductor device.  
           [0008]    The inspection socket  17  of POGO pin type shown in FIG. 10 achieves desired contact by means of applying contact pressure to the solder ball  12  from below. The contact pressure acts as a load on a package of the semiconductor device. The load imposed on the package increases with the number of pins of the semiconductor device. If excessive load is exerted on the package, the semiconductor element provided within the package will be damaged. For this reason, the inspection socket  17  of POGO pin type has a problem of being likely to inflict damage on a semiconductor device having a plurality of pins.  
         SUMMARY OF THE INVENTION  
         [0009]    The present invention has been conceived to solve such a drawback of the background art and is aimed at providing an inspection system for inspecting at high speed a semiconductor device having a plurality of pins.  
           [0010]    The present invention is also aimed at providing an inspection method of inspecting at high speed a semiconductor device having a plurality of pins.  
           [0011]    The above objects of the present invention are achieved by . . . . The . . . includes.  
           [0012]    The above objects of the present invention are achieved by . . . . The . . . includes.  
           [0013]    The above objects of the present invention are achieved by . . . . The . . . includes.  
           [0014]    Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a plan view showing a principal section of an inspection system according to a first embodiment of the present invention;  
         [0016]    [0016]FIG. 2 is a perspective view showing construction of a slide section shown in FIG. 1;  
         [0017]    [0017]FIG. 3 is a side view showing a part of the slide section shown in FIG. 1;  
         [0018]    [0018]FIG. 4 is a side view of another contact section which may be employed in the inspection system according to the first embodiment of the present invention;  
         [0019]    [0019]FIG. 5 is a perspective view of another slide section which may be employed in the inspection system according to the first embodiment of the present invention;  
         [0020]    [0020]FIG. 6 is a perspective view showing construction of a slide section provided in a second embodiment of the present invention;  
         [0021]    [0021]FIG. 7 is a side view of a part of the slide section shown in FIG. 6;  
         [0022]    [0022]FIG. 8 is a side view of another contact section which may be employed in the inspection system according to the second embodiment of the present invention;  
         [0023]    [0023]FIG. 9 is a side view showing construction of a conventional inspection socket; and  
         [0024]    [0024]FIG. 10 is a side view showing construction of another conventional inspection socket.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]    Preferred embodiments of the present invention will be described hereinafter by reference to the accompanying drawings. Throughout the drawings, like reference numerals designate like elements, and repetition of their explanations is omitted.  
         [0026]    First Embodiment  
         [0027]    [0027]FIG. 1 is a plan view showing a principal section of an inspection system according to a first embodiment of the present invention. The inspection system according to the present embodiment is for inspecting a semiconductor device of BGA or CSP type. The inspection system has an inspection socket  20  for establishing an electrical connection with solder balls which are provided as terminals on a semiconductor device to be inspected. The inspection socket  20  has a plurality of slide sections  22 . The slide sections  22  are provided on an IF substrate (not shown in FIG. 1) so as to be able to slide rightward and leftward in FIG. 1.  
         [0028]    [0028]FIG. 2 is a perspective view showing one of the slide sections  22 . As shown in FIG. 2, each of the slide sections  22  has an outer frame  28  comprising two longitudinal plates  24  and two lateral plates  26 . A plurality of tilt slits  30  are formed at predetermined pitches on each of the two longitudinal plates  24 .  
         [0029]    The slide section  22  has a plurality of contact sections  32 . The contact section  32  is a multilayered plate formed by laminating a slide guide  34  having rigidity, an elastic film  36  (for example, a silicon film) having elasticity, and a conductive contact plate  38 , in the sequence given. The contact section  32  is inserted into the tilt slit  30  and is mounted on the outer frame  28 .  
         [0030]    As shown in FIG. 1, the interior space defined by each slide section  22  is partitioned into a plurality of sub-spaces by means of the previously-described contact sections  32 . A plurality of metal protuberances  40  are formed on the IF substrate  15  (not shown in FIG. 1) located below the slide section  22  at the same pitch as used for arrangement of the solder balls of the semiconductor device to be inspected. The slide section  22  is placed on the IF substrate  15  such that metal protuberances  40  are located in the respective sub-spaces defined by the contact sections  32  and the outer frame  28 .  
         [0031]    More specifically, in the present embodiment, the contact section  32  is located on the right side of the metal protuberance  40  in the n th  slide section  22  (i.e., the first and third slide sections shown in FIG. 1). The slide sections  22  are mounted on the IF substrate  15  such that the contact sections  32  can be brought into contact with the metal protuberances  40  by means of sliding the slide sections  22  leftward. In the n+1 th  and n−1 th  slide sections  22 , which are adjacent to the nth slide section  22 , (i.e., the second and fourth rows of slide sections  22  shown in FIG. 1) are located on the left side of the contact sections  32  of the metal protuberances  40 . The slide sections  22  are mounted on the IF substrate  15  so that the contact sections  32  can be brought into contact with the metal protuberances  40  by means of sliding the slide sections  22  rightward. In the inspection system according to the present embodiment, the plurality of slide sections  22  are slid in alternating directions from row to row, to thereby bring the contact sections  32  into contact with the metal protuberances  40 .  
         [0032]    The structure and function of the slide section  22  will be described in more detail by reference to FIG. 3.  
         [0033]    [0033]FIG. 3 is a side view showing one of the sub-spaces defined in the slide section  22  by the contact section  32 . In FIG. 3, reference numeral  10  designates the bottom of a package of a semiconductor device;  12  designates solder balls provided as terminals on the bottom  10 ; and  15  designates an IF substrate of the inspection system, as in the case of the inspection system shown in FIG. 9 or  10 .  
         [0034]    The metal protuberances  40  provided on the surface of the IF substrate  15  are formed by means of plating with gold a ball which has a diameter of 1 to 2 mm and is formed from, for example, stainless steel (SUS). The metal protuberances  40  act as terminals of the IF substrate  15 . The metal protuberances  40  are embedded in or soldered to the IF substrate  15 . In the present embodiment, the metal protuberances  40  are formed in a spherical shape. However, the metal protuberances  40  may be formed into a columnar shape, a truncated cone shape, a polygonal columnar shape, or a polygonal truncated cone shape.  
         [0035]    The contact section  32  has the conductive contact plate  38  so as to oppose the metal protuberance  40 . The contact sections  32  are slid in conjunction with the slide sections  22  (see FIG. 1) and can come into contact with both the metal protuberances  40  and the solder balls  12 . As mentioned above, the contact section  32  has the elastic film  36 , and the elastic force of the elastic film  36  generates contact force upon making contact with the metal protuberance  40  and the solder ball  12 . Further, the elastic force of the elastic film  36  absorbs variations in the size of the solder ball  12 . Therefore, according to the present invention, there is no necessity of imparting elasticity to the contact plate  38  itself, and hence the length of the contact plate  38  can be made sufficiently short (a length of about  1  to  6  mm).  
         [0036]    Resistance arising between the solder ball  12  and the metal protuberance  40  becomes lower as the contact plate  38  becomes shorter. Further, the lower the resistance arising between the solder ball  12  and the metal protuberance  40 , the faster inspection of the semiconductor device can be completed. Accordingly, the inspection system according to the present embodiment enables high-speed inspection of a semiconductor device, because of the short length of the contact plate  38 .  
         [0037]    In the present embodiment, the contact section  32  comes into contact with the side surface of the solder ball  12 , as shown in FIG. 3. As mentioned above, the slide sections  22  are slid in alternating directions from row to row, whereby each of the contact sections  32  is brought into contact with the corresponding metal protuberance  40  and solder ball  12 . As a result, the contact force exerted on each solder ball  12  is canceled as a whole. For this reason, in the inspection system according to the present embodiment, the slide sections  22  are slid in predetermined directions, thereby appropriately adjusting the relative position between the semiconductor device and the IF substrate  15  to a stable state.  
         [0038]    In the present embodiment, no longitudinal pressing force acts on individual solder ball  12 . When the inspection socket  20  is attached to the package of the semiconductor device, no great force is exerted on the bottom  10  of the package. Accordingly, even in a case where a semiconductor device has a plurality of pins, the inspection system according to the present embodiment effects a stable inspection operation while preventing occurrence of shearing or fracture in the bottom  10  of the package.  
         [0039]    In the first embodiment, the elastic film  36  is interposed between the contact plate  38  and the slide guide  34 , to thereby impart elasticity to the contact section  32 . However, the structure for imparting elasticity to the contact section  32  is not limited to such an embodiment. For example, as shown in FIG. 4, affixing an elastic anisotropic conductive film  42  onto the surface of the contact plate  36  can ensure desired elasticity.  
         [0040]    In the first embodiment, the slide section  22  is embodied by means of inserting the contact section  32  into the tilt slits  30  formed in the outer frame  28 . However, the structure of the slide section  22  is not limited to such a structure. For example, as shown in FIG. 5, the slide section  22  may be embodied by means of sandwiching the contact sections  32  between sub-sections of a two-piece outer frame  44 .  
         [0041]    Second Embodiment  
         [0042]    A second embodiment of the present invention will be described by reference to FIGS. 6 through 8. FIG. 6 is a perspective view showing the slide section  22  of the inspection socket according to the present embodiment. As in the case of the first embodiment, a plurality of slide sections  22  are arranged so as to be slid in opposite directions (see FIG. 1).  
         [0043]    In the present embodiment, the slide section  22  comprises a two-piece outer frame  46  and a plurality of contact sections  32 . A plurality of bearing holes  48  are formed at predetermined pitches in the outer frame  46 . A rotary axis  50  to be fitted into a corresponding shaft bearing hole  48  is provided on either side of the contact section  32 . In the present embodiment, the rotary axes  50  of the contact section  32  are held by the corresponding bearing holes  48 , wherewith the contact section  32  is held between the sub-sections of the two-piece outer frame  46  in a rotatable manner.  
         [0044]    [0044]FIG. 7 is a side view showing the interior space of a partition which is formed in the slide section  22  by means of the contact sections  32 . As shown in FIG. 7, as in the case of the first embodiment, the metal protuberances  40  are provided on the surface of the IF substrate  15 . The semiconductor device is situated on the slide section  22  such that the respective solder balls  12  correspond to the respective metal protuberances  40 .  
         [0045]    In the present embodiment, the contact section  32  is formed by means of laminating a conductive contact plate  54  onto an injection-molded member  52  having rigidity. More specifically, the contact section  32  is formed without use of the elastic film that is required in the first embodiment. Instead, the injection-molded member  52  has the rotary axes  50  on either side thereof.  
         [0046]    When the slide section  20  is slid in a predetermined direction (see FIG. 1), the contact plate  54  can come into contact with both the metal protuberance  40  and the solder ball  12 . At this time, the contact section  32  is retained in a rotatable manner, and hence variation in the size and position of solder balls  12  is absorbed by rotation of the contact section  32 . Accordingly, without respect to whether or not the contact section  32  has a elastic film, all the solder balls  12  of the semiconductor device can attain appropriate electrical connection with the metal protuberances  40  provided on the IF substrate  15 .  
         [0047]    In the present embodiment, since the contact sections  32  do not require a elastic film, the contact sections  32  can be made thinner than those employed in the first embodiment. The inspection system and the inspection method according to the second embodiment can be applied to inspection of a semiconductor device on which the solder balls  12  are arranged at narrow pitches of less than 1.0 mm.  
         [0048]    In the second embodiment, the contact section  32  is formed by means of laminating the contact plate  38  onto the injection-molded member  52 . However, the structure of the contact section  32  is not limited to such a structure. For example, as shown in FIG. 8, the contact section  32  may be formed from only a single conductive plate, by means of punching a metal plate of BeCu or the like. In this case, the contact section  32  can be made much thinner than that shown in FIG. 7, thereby enabling formation of solder balls  12  at narrower pitches.  
         [0049]    In the second embodiment, elasticity is not imparted to the contact sections  32 . However, the present invention is not limited to such an embodiment. More specifically, even in a case where the contact section  32  is rotatable, elasticity can be imparted to the contact sections  32  in the same manner as in the case of the first embodiment.  
         [0050]    In the first and second embodiments of the present invention, the terminals of a semiconductor device are limited to the solder balls  12 . However, the present invention is not limited to such embodiments. More specifically, the inspection system and method according to the present invention are effective for inspecting all types of semiconductor device in which terminals project from a package, including a semiconductor device having solder balls.  
         [0051]    Since the present invention has been embodied in the manner as mentioned previously, the invention yields the following advantages.  
         [0052]    According to a first aspect of the present invention, a contact section is brought into contact with the side surface of a terminal of a semiconductor device, thereby enabling establishment of electrical connection between the terminal and a metal protuberance provided on an interface substrate. Accordingly, even in a case where a package of a semiconductor device has a plurality of terminals, the inspection system according to the present invention can prevent exertion of excessive stress onto the package without fail.  
         [0053]    According to a second aspect of the present invention, contact sections can be brought into contact with terminals which are provided on a semiconductor device in a plurality of rows, from alternating directions. The contact force imposed on each terminal of the semiconductor device is canceled. Thus, the package can be placed in position without involvement of application of longitudinal stress onto the package.  
         [0054]    According to a third aspect of the present invention, since the contact section has a length of  1  to  6  mm, resistance arising between a terminal of a semiconductor device and a metal protuberance provided on an interface substrate can be made sufficiently low. Thus, the present invention enables high-speed testing of a semiconductor device.  
         [0055]    According to a fourth aspect of the present invention, since the contact section is provided in a rotatable manner, variation in the position and dimension of a terminal of a semiconductor device can be absorbed by means of rotation of the contact section.  
         [0056]    According to a fifth aspect of the present invention, a contact section can be held on an outer frame of a slide section through use of a simple structure.  
         [0057]    According to a sixth aspect of the present invention, the contact section is formed from a multilayered film, the film comprising a contact plate, a elastic film, and a slide guide. Therefore, according to the present invention, variations in the position and dimension of a terminal of a semiconductor device are absorbed by a elastic film, as a result of which a desired contact force arises in the elastic film.  
         [0058]    According to a seventh aspect of the present invention, the contact section is formed from a multilayered film, the film comprising an anisotropic conductive film, a contact plate, and a slide guide. Therefore, variations in the position and dimension of a terminal provided on the semiconductor device are absorbed by an anisotropic conductive film. A desired contact force can be generated in an anisotropic conductive film.  
         [0059]    According to an eighth aspect of the present invention, the contact section is formed from only a contact plate or from only a contact plate and a molded member. Therefore, in contrast with a case where the contact section includes a elastic film or an anisotropic conductive film, the contact section can be made thinner. Thus, the present invention enables appropriate inspection of a semiconductor device in which terminals are provided at sufficiently small pitches.  
         [0060]    According to a ninth aspect of the present invention, a semiconductor device can be appropriately inspected without imparting damage to the semiconductor device and through use of the inspection system.  
         [0061]    Further, the present invention is not limited to these embodiments, but variations and modifications may be made without departing from the scope of the present invention.  
         [0062]    The entire disclosure of Japanese Patent Application No. 2000-188384 filed on Jun. 22, 2000 including specification, claims, drawings and summary are incorporated herein by reference in its entirety.