Patent Publication Number: US-2022214376-A1

Title: Contact probe

Description:
TECHNICAL FIELD 
     The present invention relates to a contact probe. 
     BACKGROUND ART 
     For electrical contact between a semiconductor package to be inspected and an inspection device, a contact probe and a socket supporting the contact probe are used. In the socket, a plurality of contact probes corresponding to terminals provided in the semiconductor package are supported. When the socket is brought close to the semiconductor package to be inspected, a distal end of the contact probe comes into contact with the terminal on a semiconductor package side and is electrically connected. 
     For example, Patent Literature 1 discloses a technique relating to a socket capable of narrowing a support interval of a contact probe. Patent Literature 2 discloses a contact probe capable of reducing a risk of decreasing a strength of a plunger and a difficulty of tube processing. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP-A-2018-071991 
     Patent Literature 2: JP-A-2018-194411 
     SUMMARY OF INVENTION 
     Technical Problem 
     Some of the terminals of the semiconductor package to be inspected have a recess as an indicator for image inspection in a mounting process. A shape of the recess can be variously set by a manufacturer of the semiconductor package. One of the terminals of the semiconductor package is a dimpled terminal portion  81  as shown in  FIG. 21 . The dimpled terminal portion  81  has a quarter spherical recess called a dimple  82  at a protruding corner portion of the terminal. This dimpled terminal portion  81  is used, for example, in a quad flat non-leaded package (QFN) for an in-vehicle device. 
     In the related art, in an inspection of the semiconductor package including the dimpled terminal portion  81 , a contact probe having a wedge-shaped distal end portion  11 J (or a cone or pyramid shaped distal end) plunger as shown in  FIG. 22  has been used. 
     When the inspection is executed using the contact probe having the wedge-shaped distal end portion  11 J, it is necessary to execute the inspection such that the distal end is brought into contact with a flat portion (a flat portion around the dimple  82 ) of the dimpled terminal portion  81  aiming at a pinpoint. However, due to an error, a variation, or the like in a positional relation with the semiconductor package to be conveyed and provided for the inspection, as shown in  FIG. 23 , a protruding end of a distal end portion  11 J may enter an inside of the dimple  82 . Even in this case, if an inside of the dimple  82  is in a clean state such as a dust free, even when the protruding end of the distal end portion  11 J comes into contact with an inner surface of the dimple  82 , or even when an inclined portion of the distal end portion  11 J comes into contact with a periphery of the dimple  82 , conduction between the distal end portion  11 J and the dimpled terminal portion  81  can be secured. 
     However, the inside of the dimple  82  is not necessarily in the clean state such as the dust free. In a manufacturing process of the semiconductor package, there is a process of cutting a surface from which a terminal is exposed for each molding material and aligning the surface. After the cutting, cleaning is performed. However, since a size of the dimple  82  is extremely small, a cutting powder at a time of cutting may remain in the dimple  82  occasionally. When the protruding end of the distal end portion  11 J enters the dimple  82  in a state in which the cutting powder remains in the dimple  82 , normal conduction may be inhibited due to the cutting powder, and an accurate inspection result may not be obtained. 
     Therefore, as shown in  FIG. 24 , it is conceivable to use a plunger including a distal end portion  11 K formed only by a flat surface that has a wedge shape in a side view but whose protruding end has a width enough to straddle the dimple  82 . In this case, since the protruding end of the distal end portion  11 K does not enter the inside of the dimple  82  and straddles the dimple  82 , it is conceivable that, regardless of the state in the dimple  82 , the conduction between the distal end portion  11 K and the dimpled terminal portion  81  can be attained and the inspection can be executed. However, there is a problem in this case. 
     An error or a variation occurs in a positional relation between the distal end portion  11 K and the semiconductor package to be conveyed and provided for the inspection. When deviation occurs in a contact position between the distal end portion  11 K and the dimpled terminal portion  81 , a portion of the flat surface of the distal end portion  11 K may come out of the dimpled terminal portion  81  and come into contact with the molding material around the dimpled terminal portion  81 . The molding material often contains glass fiber. When the distal end portion  11 K comes into contact with the molding material, wear is larger than that in a case in which the distal end portion  11 K of the plunger is in contact with the dimpled terminal portion  81 , and a life of the contact probe is shortened. An accurate inspection result may not be obtained due to the distal end portion  11 K being in contact with the molding material. 
     An object of the present invention is to provide a technique of a contact probe suitable for an inspection of a semiconductor package in which a recess is formed in a terminal portion of the semiconductor package. 
     Solution to Problem 
     An aspect of the present invention provides a contact probe capable of being used for an inspection of a semiconductor package in which a recess is formed in a terminal portion, the contact probe including a plunger including a distal end portion that comes into contact with the terminal portion, in which the distal end portion includes a protruding portion protruding toward the terminal portion and a shoulder portion having a protruding height toward the terminal portion lower than that of the protruding portion. 
     According to the present aspect, when the contact probe attempts to come into contact with the terminal portion, the protruding portion enters a recess, while the shoulder portion comes into contact with an outer peripheral portion (a flat surface around the recess of the terminal portion) of the recess of the terminal portion. Therefore, even in a situation in which a foreign matter such as dust or a cutting powder remains in the recess and a foreign matter is interposed between the protruding portion and an inside of the recess, conduction (electrical connection) between the contact probe and the terminal portion is secured by the contact of the shoulder portion with the terminal portion, and an accurate inspection can be executed. Further, according to the present aspect, since the shoulder portion is less likely to come into contact with the molding material around the terminal portion, a life of the contact probe can be extended. The contact probe suitable for the inspection of the semiconductor package in which the recess is formed in the terminal portion can be implemented. 
     In the contact probe according to the present aspect, even if the contact probe is used for the inspection of the semiconductor package having a flat terminal portion without a recess, since the protruding portion is brought into contact with the contact probe to secure the conduction between the contact probe and the terminal portion, it is also possible to execute an accurate inspection. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view showing a state of an inspection of a contact probe and a semiconductor package according to a first embodiment. 
         FIG. 2  is an enlarged perspective view of a distal end portion of the contact probe according to the first embodiment. 
         FIG. 3  is a front view of the distal end portion of the contact probe according to the first embodiment as viewed from a direction perpendicular to a probe axis. 
         FIG. 4  is a view (No. 1) showing a state in which the distal end portion according to the first embodiment is brought into contact with a dimpled terminal portion in a positional relation in which a protruding portion enters a recess. 
         FIG. 5  is a view (No. 2) showing a state in which the distal end portion according to the first embodiment is brought into contact with the dimpled terminal portion in the positional relation in which the protruding portion enters the recess. 
         FIG. 6  is a view (No. 1) showing a state in which the distal end portion according to the first embodiment is brought into contact with the dimpled terminal portion in a positional relation in which the protruding portion is separated from the recess. 
         FIG. 7  is a view (No. 2) showing a state in which the distal end portion according to the first embodiment is brought into contact with the dimpled terminal portion in the positional relation in which the protruding portion is separated from the recess. 
         FIG. 8  is a perspective view showing a state of Kelvin measurement using the contact probe including the distal end portion according to the first embodiment. 
         FIG. 9  is an enlarged perspective view of a distal end portion of a contact probe according to a second embodiment. 
         FIG. 10  is a front view of the distal end portion of the contact probe according to the second embodiment as viewed from a direction perpendicular to a probe axis. 
         FIG. 11  is a view showing a state in which the distal end portion according to the second embodiment is brought into contact with the dimpled terminal portion in a positional relation in which a protruding portion enters a recess. 
         FIG. 12  is an enlarged perspective view of a distal end portion of a contact probe according to a third embodiment. 
         FIG. 13  is a front view of the distal end portion of the contact probe according to the third embodiment as viewed from a direction perpendicular to a probe axis. 
         FIG. 14  is a view showing a state in which the distal end portion according to the third embodiment is brought into contact with the dimpled terminal portion in a positional relation in which a protruding portion enters a recess. 
         FIG. 15  is a view showing a modification of the distal end portion of the contact probe according to the first embodiment. 
         FIG. 16  is a view showing a modification of the distal end portion of the contact probe according to the first embodiment. 
         FIG. 17  is a view showing a modification of the distal end portion of the contact probe according to the second embodiment. 
         FIG. 18  is a view showing a modification of the distal end portion of the contact probe according to the third embodiment. 
         FIG. 19  is a view showing a modification of the distal end portion of the contact probe. 
         FIG. 20  is a view showing a modification of the distal end portion of the contact probe. 
         FIG. 21  is a perspective view showing an example of the dimpled terminal portion. 
         FIG. 22  is an enlarged perspective view (No. 1) of a distal end portion of a related-art contact probe. 
         FIG. 23  is a view showing a state in which the related-art contact probe is brought into contact with a dimpled terminal portion. 
         FIG. 24  is an enlarged perspective view (No. 2) of the distal end portion of the related-art contact probe. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, examples of a preferred embodiment of the present invention will be described. However, a mode to which the present invention can be applied is not limited to the following embodiments. The drawings in which a distal end portion of a contact probe is enlarged show three orthogonal axes to indicate a common direction in each drawing. A Z axis of the three orthogonal axes indicates a direction parallel to an axis (a longitudinal direction) of the contact probe, and a Z axis positive direction is a direction from the contact probe toward a semiconductor package. An X axis positive direction is referred to as a forward direction, an X axis negative direction is referred to as a rearward direction, a Y axis positive direction is referred to as a rightward direction, and a Y axis negative direction is referred to as a leftward direction. 
     First Embodiment 
       FIG. 1  is a perspective view showing a state of an inspection of a contact probe and a semiconductor package according to a first embodiment. 
     A contact probe  10  is designed to be usable for an inspection of a semiconductor package  80 . 
     The semiconductor package  80  is a non-lead type semiconductor package including a dimpled terminal portion  81  as a connection terminal soldered to a mounting substrate. In  FIG. 1 , a shaded portion around the dimpled terminal portion  81  is a molding material. 
       FIG. 2  is an enlarged perspective view of a distal end portion  11 A (corresponding to a lower end portion of the contact probe  10  shown in  FIG. 1 ) of the contact probe  10 . More specifically, the distal end portion  11 A corresponds to a distal end portion of a plunger  10   a  (see  FIG. 1 ) provided in the contact probe  10 . 
       FIG. 3  is a front view (a view showing a surface facing the X axis positive direction) of the distal end portion  11 A of the contact probe  10  as viewed from a direction (the X axis positive direction) perpendicular to a probe axis Sp (a longitudinal axis of the contact probe  10 ). 
     The distal end portion  11 A of the contact probe  10  includes 1) a protruding portion  12  that protrudes in a distal end direction (the Z axis positive direction) and that is located at a position away from a probe center in a distal end front view, and 2) a shoulder portion  13  having a protruding height in the distal end direction lower than that of the protruding portion  12 . Here, the “distal end front view” means a direction of a visual line when the distal end portion  11 A is viewed from an axial direction (the Z axis positive direction) of the probe axis Sp as shown in  FIG. 2 . 
     A front surface  14 F (a surface facing the X axis positive direction) of the distal end portion  11 A and a back surface  14 B (a surface facing the X axis negative direction) of the distal end portion  11 A are formed such that a part of a side surface of a cylinder, which is a basic shape of the plunger  10   a , remains as it is. A flat surface  14 R and a flat surface  14 L are respectively formed at left and right side surfaces (surfaces facing the Y axis positive direction and the Y axis negative direction) of the distal end portion  11 A. In the distal end portion  11 A, an inclined surface  15  is formed from the back surface  14 B of the distal end portion toward the front surface  14 F of the distal end portion such that a cross-sectional area of a probe cross section S (a cross section whose normal line is oriented in the Z axis direction) decreases toward the distal end. 
     The protruding portion  12  and the shoulder portion  13  are formed at an inclined upper portion of the inclined surface  15 , and are at a position closer to the X axis positive direction with respect to the probe center (a position of the probe axis Sp) in the distal end front view. 
     A protruding end of the protruding portion  12  has a flat shape whose normal line is parallel to the probe axis Sp. 
     Similarly to the protruding portion  12 , a distal end of the shoulder portion  13  also has a flat shape whose normal line is parallel to the probe axis Sp. 
     When the distal end portion  11 A is viewed in the distal end front view, the shoulder portions  13  are located on both sides interposing the protruding portion  12  in a circumferential direction. It can be said that the distal end portion  11 A has a convex stepped shape in which the shoulder portions  13  are formed on both sides of the one protruding portion  12 . A plurality of the shoulder portions  13  are located around the protruding portion  12 . When viewed from a left side surface (the Y axis negative direction) or a right side surface (the Y axis positive direction), the distal end portion  11 A has a one-sided wedge shape. 
       FIGS. 4 and 5  are views showing a state in which the distal end portion  11 A is brought into contact with the dimpled terminal portion  81  in a positional relation in which the protruding portion  12  enters the dimple  82  (the recess) of the dimpled terminal portion  81 . Specifically,  FIG. 4  is a view of the distal end portion  11 A as viewed obliquely behind the distal end portion  11 A, and  FIG. 5  is a view of the distal end portion  11 A as viewed from a package outer circumferential direction (a back surface side of the distal end portion  11 A) of the dimpled terminal portion  81 . 
     The distal end portion  11 A is formed in a shape in which, when the protruding portion  12  is moved toward the dimple  82  of the dimpled terminal portion  81 , the shoulder portion  13  comes into contact with a periphery (a flat portion of the dimpled terminal portion  81 , a flat portion around the dimple  82 ) of the dimple  82  of the dimpled terminal portion  81  before the protruding end of the protruding portion  12  reaches a bottom of the dimple  82 . 
     Specifically, a left-right width (a width in the Y axis direction) of the protruding portion  12  is set to be smaller than a left-right width (a diameter of a sphere when the dimple  82  is a quarter spherical recess) of the dimple  82  of the dimpled terminal portion  81  of the semiconductor package  80  to be inspected. A protruding dimension (a height from the shoulder portion  13  in the Z axis direction: a height of the step) of the protruding portion  12  is set to be smaller than the maximum depth (a radius of the sphere when the dimple  82  is the quarter spherical recess) from the flat surface around the dimple  82  of the dimpled terminal portion  81  to a bottom surface of the dimple  82 . That is, a difference between the protruding height of the protruding end of the protruding portion  12  and the protruding height of the shoulder portion  13  is set to be smaller than the maximum depth of the dimple  82 . 
     Therefore, in a positional relation in which the protruding portion  12  enters the dimple  82 , when the contact probe  10  approaches the dimpled terminal portion  81 , the protruding portion  12  enters the dimple  82 , and the shoulder portion  13  abuts against the flat surface around the dimple  82 . Therefore, even if a foreign matter remains in the dimple  82 , the shoulder portion  13  is brought into direct contact with the flat surface of the dimpled terminal portion  81  around the dimple  82  to be reliably conducted, and the inspection of the semiconductor package  80  can be accurately executed regardless of the presence or absence of the foreign matter in the dimple  82 . 
     The shape of the dimple  82  according to the present embodiment is a substantially quarter sphere (approximately ¼ sphere) shape opened in two directions which are a side with which the contact probe  10  is in contact and an outer circumferential side of four sides of a package. Therefore, the protruding portion  12  enters the dimple  82 , so that the foreign matter remaining in the dimple  82  can be pushed out from the dimple  82 . 
       FIGS. 6 and 7  are views showing a state in which the distal end portion  11 A is brought into contact with the dimpled terminal portion  81  in a positional relation in which the protruding portion  12  is separated from the dimple  82 .  FIG. 6  is a view of the distal end portion  11 A as viewed obliquely behind the distal end portion  11 A, and  FIG. 7  is a view of the distal end portion  11 A as viewed from the package outer circumferential direction (the back surface side of the distal end portion  11 A) of the dimpled terminal portion  81 . 
     In the present embodiment, the distal end portion  11 A is formed in a shape in which, when the protruding portion  12  is moved toward the dimple  82 , the shoulder portion  13  comes into contact with the periphery of the dimple  82  of the terminal portion  11 A before the protruding end of the protruding portion  12  reaches the bottom of the dimple  82 . If in the positional relation in which the protruding portion  12  is separated from the dimple  82 , the protruding portion  12  comes into direct contact and conducts with the flat surface around the dimple  82 . The semiconductor package  80  to be conveyed and provided for the inspection is not always provided at an accurate same position, and an error or a variation occurs in the providing position. Therefore, in the positional relation in which the protruding portion  12  is separated from the dimple  82 , the distal end portion  11 A may come into contact with the dimpled terminal portion  81  to perform a test. However, even in this case, the protruding portion  12  is brought into direct contact with the flat surface around the dimple  82 , and reliable conduction can be achieved. 
     Focusing on the shoulder portion  13 , the shoulder portion  13  at either one of the left and right sides protrudes from the dimpled terminal portion  81 . However, since the protruding height of the shoulder portion  13  is smaller than the protruding height of the protruding portion  12 , the shoulder portion  13  does not touch a molding portion (a portion of the molding material around the dimpled terminal portion  81 ). A material forming the molding portion often contains a glass fiber material. In the manufacturing process of the semiconductor package  80 , a flat surface may be formed by collectively cutting the contact surface with the contact probe with the molding portion and the dimpled terminal portion  81 . In this case, when the shoulder portion  13  comes into contact with a surface of the molding portion, the shoulder portion  13  is worn as if the shoulder portion  13  is brought into contact with sandpaper, and the shoulder portion  13  is worn more than when the shoulder portion  13  comes into contact with the flat portion (the flat surface) of the dimpled terminal portion  81 . However, in the present embodiment, since the shoulder portion  13  is maintained in a state of being away from the molding portion, the wear does not occur. 
       FIG. 8  is a perspective view showing a state of Kelvin measurement using the contact probe including the distal end portion  11 A. A first contact probe  10   a  and a second contact probe  10   b  are brought into contact with the one dimpled terminal portion  81 . 
     As described above, the protruding portion  12  and the shoulder portion  13  are formed at the position offset from the probe center in the distal end front view. Therefore, when the first contact probe  10   a  and the second contact probe  10   b  are set to a relative posture (in other words, a relative posture in which the front surfaces  14 F of the first contact probe  10   a  and the second contact probe  10   b  face each other back to back) in which the protruding portions  12  of the first contact probe  10   a  and the second contact probe  10   b  are brought close to each other, the Kelvin measurement can be executed by simultaneously bringing the two probes into contact with the minimum dimpled terminal portion  81 . 
     Second Embodiment 
     Next, a second embodiment will be described. The same elements as those according to the first embodiment are denoted by the same reference numerals as those according to the first embodiment, and a duplicate description thereof will be omitted. 
       FIG. 9  is an enlarged perspective view of a distal end portion  11 B of the contact probe  10  according to the second embodiment. 
       FIG. 10  is a front view (a view showing a surface facing the X axis positive direction) of the distal end portion  11 B of the contact probe  10  according to the second embodiment as viewed from a direction (the X axis positive direction) perpendicular to the probe axis Sp (the longitudinal axis of the contact probe  10 ). 
     Similarly to the distal end portion  11 A, the distal end portion  11 B is also formed in a shape in which, when the protruding portion  12  is moved toward the dimple  82 , a shoulder portion  13 B comes into contact with a periphery of the dimple  82  of the dimpled terminal portion  81  before a protruding end of the protruding portion  12  reaches a bottom of the dimple  82 . 
     Specifically, the distal end portion  11 B has a shape in which a cross-sectional area of the probe cross section S decreases toward the distal end. A protruding end of the protruding portion  12  has a flat shape whose normal line is parallel to the probe axis Sp. However, a distal end of the shoulder portion  13 B of the distal end portion  11 B has an inclined shape. The shoulder portion  13 B has an inclination direction parallel to the inclined surface  15  and an inclination angle parallel to the inclined surface  15  and an intersecting portion with the front surface  14 F, that is, the distal end of the shoulder portion  13 B has an inclined shape. The maximum value of the difference between the protruding height of the protruding end of the protruding portion  12  and the protruding height of the shoulder portion  13 B is set to be smaller than the maximum depth of the dimple  82 . The shoulder portion  13 B may be inclined in a direction opposite to the inclination direction of the inclined surface  15 . 
       FIG. 11  is a view showing a state in which the distal end portion  11 B is brought into contact with the dimpled terminal portion  81  in a positional relation in which the protruding portion  12  enters the dimple  82 , and is a view of the distal end portion  11 B as viewed from a package outer circumferential direction (a back surface side of the distal end portion  11 B) of the dimpled terminal portion  81 . 
     The protruding portion  12  enters the dimple  82  and is not in contact with an inner surface of the dimple  82 . However, the shoulder portion  13 B is in point contact with an outer edge portion of the dimple  82  to secure conduction. Therefore, also in the second embodiment, the same effects as the first embodiment can be attained. While the shoulder portion  13  is in surface contact or line contact with the dimpled terminal portion  81  in the first embodiment, the shoulder portion  13 B is in point contact with the dimpled terminal portion  81  in the second embodiment. Therefore, it is less likely to pinch a foreign matter than in the first embodiment. Therefore, in the second embodiment, a more accurate inspection result may be obtained as compared with the first embodiment. Also in the second embodiment, the Kelvin measurement can be executed in the same manner as in the first embodiment. 
     Third Embodiment 
     Next, a third embodiment will be described. The same elements as those according to the first embodiment or the second embodiment are denoted by the same reference numerals, and a duplicate description thereof will be omitted. 
       FIG. 12  is an enlarged perspective view of a distal end portion  11 C of the contact probe  10  according to the third embodiment. 
       FIG. 13  is a front view (a view showing a surface facing the X axis positive direction) of the distal end portion  11 C of the contact probe  10  as viewed from a direction (the X axis positive direction) perpendicular to the probe axis Sp (a longitudinal axis of the contact probe  10 ). 
     Similarly to the distal end portion  11 A and the distal end portion  11 B, the distal end portion  11 C is also formed in a shape in which, when the protruding portion  12 C is moved toward the dimple  82 , a shoulder portion  13   C comes  into contact with a periphery of the dimple  82  of the dimpled terminal portion  81  before a protruding end of the protruding portion  12 C reaches a bottom of the dimple  82 . That is, the maximum value of a difference between a protruding height of a protruding end of the protruding portion  12  and a protruding height of the shoulder portion  13 C is set to be smaller than the maximum depth of the dimple  82 . 
     The distal end portion  11 C has a shape in which a cross-sectional area of a probe cross section decreases toward a distal end. The protruding portion  12 C includes a protruding end having a chevron shape in a front view as viewed from the X axis positive direction, and a distal end of the protruding portion  12 C forms one ridgeline in a front-rear direction (a direction along the X axis direction). The shoulder portion  13 C also includes a protruding end having a chevron shape in the front view, and a distal end of the shoulder  13 C forms one ridgeline in the front-rear direction. 
       FIG. 14  is a view showing a state in which the distal end portion  11 C is brought into contact with the dimpled terminal portion  81  in a positional relation in which the protruding portion  12 C enters the dimple  82 , and is a view of the distal end portion  11 C as viewed from a package outer circumferential direction (a back surface side of the distal end portion  11 C) of the dimpled terminal portion  81 . 
     The protruding portion  12 C enters the dimple  82  and is not in contact with an inner surface of the dimple  82 . However, the shoulder portion  13 C is in point contact with an outer edge portion (a flat surface around the dimple  82 ) of the dimple  82  to secure conduction. Therefore, also in the third embodiment, the same effects as the first embodiment can be attained. Also in the third embodiment, as in the second embodiment, since the shoulder portion  13 C is in point contact with the dimpled terminal portion  81 . Therefore, it is less likely to pinch a foreign matter than in the first embodiment. Therefore, in the third embodiment, a more correct inspection result may be obtained as compared with the first embodiment. Also in the third embodiment, the Kelvin measurement can be executed in the same manner as in the first embodiment and the second embodiment. 
     Several embodiments have been described above. However, the mode to which the present invention can be applied is not limited to the above-described embodiments, and the addition, omission, and change of the constituent elements can be executed as appropriate. 
     For example, an area of a protruding portion  12 D may be made smaller than that of the protruding portion  12  according to the first embodiment, as in a distal end portion  11 D shown in  FIG. 15 , based on the distal end portion  11 A according to the first embodiment. Furthermore, the flat surface may be made smaller so as to disappear, and the distal end of the protruding portion  12 D may have an inclined shape. 
     Further, for example, a V-shaped notch  125  along the front-rear direction (the X axis direction) may be formed in a central portion (a central portion in the Y axis direction) of a protruding portion  12 E in the left-right direction, as in a distal end portion  11 E shown in  FIG. 16 , based on the distal end portion  11 A according to the first embodiment. Left and right protruding end surfaces  121  with the notch  125  interposed therebetween are end surfaces excluding the notch  125  from the protruding portion  12  according to the first embodiment. An area of a distal end of the protruding portion  12 E when the protruding portion  12 E enters the dimple  82  (the recess) is smaller than an area of the end surface of the protruding portion  12  according to the first embodiment since the area of the distal end of the protruding portion  12 E is an area of the protruding end surface  121 . A volume of the protruding portion  12 E is smaller than that of the protruding portion  12  according to the first embodiment by an amount of the notch  125 . Therefore, when a foreign matter remains in the dimple  82 , even when the protruding portion  12  according to the first embodiment interferes depending on a size and an amount of the foreign matter, the protruding portion  12 E may not interfere. As compared with the protruding portion  12  according to the first embodiment, the protruding portion  12 E is less likely to be affected by the foreign matter. 
     Even when the distal end portion  11 E comes into contact with the dimpled terminal portion  81  in a positional relation in which the protruding portion  12 E is separated from the dimple  82 , since the contact area is the area of the protruding end surface  121 , the protruding portion  12 E is less likely to pinch the foreign matter as compared with the protruding portion  12  according to the first embodiment. 
     Similarly, for example, the V-shaped notch  125  along the front-rear direction (the X axis direction) may be formed in a central portion (a central portion in the Y axis direction) of a protruding portion  12 F in the left-right direction, as in a distal end portion  11 F shown in  FIG. 17 , based on the distal end portion  11 B according to the second embodiment. The left and right protruding end surfaces  121  with the notch  125  interposed therebetween are end surfaces excluding the notch  125  from the protruding portion  12  according to the second embodiment. 
     A shape of the notch  125  is not limited to a V shape, and may be an arc shape in cross section. The shape of the notch  125  is preferably a shape in which the notch  125  is formed in a groove shape over lengths of the protruding portions  12 E,  12 F in the front-rear direction (the X axis direction). 
     In the distal end portion  11 E shown in  FIG. 16  or the distal end portion  11 F shown in  FIG. 17 , the protruding end surface  121  may be a flat surface, or may have a ridgeline shape in which a width of the protruding end surface  121  in the Y axis direction is extremely reduced according to the size of the notch  125 . 
     Similarly, the notch  125  may be formed also in the protruding portion  12 D in  FIG. 15 . 
     For example, a protruding portion  12 H may have a cone or pyramid shape by shortening a ridgeline of a protruding end of the protruding portion  12 H to a point, as in a distal end portion  11 H shown in  FIG. 18 , based on the distal end portion  11 C according to the third embodiment. 
     Similarly, based on the distal end portion  11 E shown in  FIG. 16 , the lengths of the two protruding end surfaces  121  (the ridgeline portions) of the protruding end of the protruding portion  12 E in the X axis direction may be reduced, and each protruding end surface  121  may have a cone or pyramid shape as the protruding portion  12 H of the distal end portion  11 H shown in  FIG. 18 . A point is obtained when the width of the protruding end surface  121  in the Y axis direction and the length of the protruding end surface  121  in the X axis direction are reduced to the utmost limit. 
     Similarly, based on the distal end portion  11 F shown in  FIG. 17 , the lengths of the two protruding end surfaces  121  (the ridgeline portions) of the protruding end of the protruding portion  12 F in the X axis direction may be reduced, and each protruding end surface  121  may have a cone or pyramid shape as the protruding portion  12 H of the distal end portion  11 H shown in  FIG. 18 . A point is obtained when the width of the protruding end surface  121  in the Y axis direction and the length of the protruding end surface  121  in the X axis direction are reduced to the utmost limit. 
     As in the distal end portion  11 L in  FIG. 19  or the distal end portion  11 M in  FIG. 20 , the protruding portion  12  may be provided on an extension line of the probe axis Sp. In the distal end portion  11 L in  FIG. 19 , the protruding portion  12  has a cone shape in which a vertex is located on the extension line of the probe axis Sp. In the distal end portion  11 M in  FIG. 20 , the protruding portion  12  has a truncated cone shape in which the extension line of the probe axis Sp is a rotation axis. 
     The disclosed content of the present specification can be summarized as follows. 
     An aspect of the present disclosure provides a contact probe capable of being used for an inspection of a semiconductor package in which a recess is formed in a terminal portion, the contact probe including a plunger including a distal end portion that comes into contact with the terminal portion, in which the distal end portion includes a protruding portion protruding toward the terminal portion and a shoulder portion having a protruding height toward the terminal portion lower than that of the protruding portion. 
     According to the present aspect, when the contact probe attempts to come into contact with the terminal portion, the protruding portion enters a recess, while the shoulder portion comes into contact with an outer peripheral portion (a flat surface around the recess of the terminal portion) of the recess of the terminal portion. Therefore, even in a situation in which a foreign matter such as dust or a cutting powder remains in the recess and a foreign matter is interposed between the protruding portion and an inside of the recess, conduction (electrical connection) is secured by the contact of the shoulder portion with the terminal portion, and an accurate inspection can be executed. Further, according to the present aspect, since the shoulder portion is less likely to come into contact with the molding material around the terminal portion, a life of the contact probe can be extended. The contact probe suitable for the inspection of the semiconductor package in which the recess is formed in the terminal portion can be implemented. 
     In the contact probe according to the present aspect, even if the contact probe is used for the inspection of the semiconductor package having a flat terminal portion without a recess, since the protruding portion is brought into contact with the contact probe to secure the conduction, it is also possible to execute an accurate inspection. 
     A difference between the protruding height of the protruding end of the protruding portion and the protruding height of the shoulder portion may be smaller than a depth of the recess. 
     Accordingly, even if a foreign matter is present in the recess, the conduction executed by the shoulder portion can be secured. 
     The distal end portion may have a shape in which a cross-sectional area of a probe cross section decreases toward a distal end. 
     Accordingly, the distal end of the contact probe can have a shape in which the cross-sectional area is smaller toward the distal end. When the number of the protruding portions of the distal end is one, the shape is tapered as a whole. Since the area in which the contact probe is in contact with the terminal portion is small, a contact pressure per unit area can be increased and reliable contact can be achieved. By providing the protruding portion offset from a probe center in the distal end front view, it is easy to execute the so-called Kelvin measurement in which the protruding portions of the two contact probes are brought into contact with one terminal portion and measured. 
     The shoulder portion is provided as a plurality of shoulder portions and may be located around the protruding portion. 
     Accordingly, it is easy to secure the conduction executed by the shoulder portion regardless of a direction in which the protruding portion deviates with respect to the recess. 
     A protruding end of the protruding portion may have a flat shape. 
     Accordingly, even if the contact probe is used for the inspection of the semiconductor package having the flat terminal portion without a recess, the protruding portion is easily brought into surface contact or line contact with the terminal portion, and the conduction is easily secured. 
     A protruding end of the protruding portion may have a chevron shape. 
     A protruding end of the protruding portion may have a cone or pyramid shape. 
     The protruding portion may have a notch. 
     A distal end of the shoulder portion may have a flat shape. 
     Accordingly, the contact between the shoulder portion and the outer peripheral portion of the recess of the terminal portion is likely to be a surface contact or a line contact, and the conduction can be easily secured. 
     A distal end of the shoulder portion may have an inclined shape. 
     A distal end of the shoulder portion may have a chevron shape. 
     Accordingly, the contact between the shoulder portion and the outer peripheral portion of the recess of the terminal portion is likely to be a point contact, and it is possible to reduce a chance that the foreign matter is interposed at a contact position as compared with a case of the surface contact or the line contact. 
     REFERENCE SIGNS LIST 
     
         
         
           
               10  contact probe 
               11 A,  11 B,  11 C,  11 D,  11 E,  11 J,  11 K,  11 L,  11 M distal end portion 
               12 ,  12 C,  12 D,  12 E protruding portion 
               13 ,  13 B,  13 C shoulder portion 
               14 B back surface 
               14 F front surface 
               14 L flat surface 
               14 R flat surface 
               15  inclined surface 
               80  semiconductor package 
               81  dimpled terminal portion 
               82  dimple (recess) 
             S probe cross section 
             Sp probe axis