JP2015173205A - Semiconductor device and wire bonding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device in which the occurrence of an open circuit and a pad and a short circuit between a wire and a pad is inhibited; and provide a wire bonding device for manufacturing the semiconductor device.SOLUTION: A semiconductor device comprises: a semiconductor chip 10 having bonding pads 12 to be rectangular first connection regions which are arranged in a first direction; and circuit boards 14 having bonding leads 16 to be second connection regions, respectively, which are arranged in the first direction. The first connection regions and the second connection regions are respectively connected by wire bonding by a wedge bonding method. A first bonding point 25 and a second bonding point 26 each having a substantially elliptic shape are arranged in each first connection region in a second direction perpendicular to the first direction. A third bonding point 27 has a substantially elliptic shape and is formed on the second connection region . A longer direction of the first bonding point 25 is oriented to the second direction. When assuming that a direction linking the second bonding point 26 and the third bonding point 27 is a third direction, a longer direction of the second bonding point 26 is oriented to the third direction rather to the second direction.

Description

  Embodiments described herein relate generally to a semiconductor device and a wire bonding apparatus.

  In wire bonding using the wedge bonding method, when bonding a wire to a pad or the like, depending on the positional relationship between the bonding point on the semiconductor chip and the bonding point on the circuit board and the direction in which the wire is routed, Opening may occur.

JP 2012-15263 A

  Provided are a semiconductor device in which the occurrence of open and short between wires and pads is suppressed, and a wire bonding apparatus for manufacturing the semiconductor device.

  The semiconductor device according to the present embodiment includes a circuit board and a semiconductor chip mounted on the circuit board. The semiconductor chip has a rectangular shape on the upper surface thereof, and is arranged in the first direction so that at least two bonding pads serving as the first connection region face the short sides. In the circuit board, at least two bonding leads to be the second connection region are arranged in the first direction. The first connection region and the second connection region corresponding to the first connection region are connected by the first bonding point, the second bonding point, and the third bonding point by wire bonding by the wedge bonding method. The first and second junction points have a substantially oval shape, and are formed on the first connection region and arranged in a second direction perpendicular to the first direction. The third junction point has a substantially elliptical shape and is formed on the second connection region. The longitudinal direction of the first joint point is in the second direction. When the direction connecting the second junction point and the third junction point is the third direction, the longitudinal direction of the second junction point is the direction from the second direction toward the third direction. Is formed.

Example of configuration diagram of wire bonding apparatus in this embodiment An example of a plan view schematically showing the outline of wire bonding (A)-(c) is an example of the figure for demonstrating the order of the wire bonding in this embodiment later on in order of a process An example of a longitudinal section for schematically explaining the structure of a wedge tool (A)-(e) is an example of the figure for demonstrating the procedure of the wire bonding in this embodiment later on in order of a process An example of a flowchart showing the procedure of the wire bonding method (A) And (b) is an example of the top view at the time of forming one junction in a pad

  Hereinafter, embodiments will be described with reference to the drawings. The drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like do not necessarily match those of the actual one. Even when the same part is represented, the dimensions and ratios may be represented differently depending on the drawing. The vertical and horizontal directions also indicate relative directions when the circuit formation surface side of the semiconductor substrate is up, and do not necessarily match the direction based on the gravitational acceleration direction. In the present specification and drawings, the same elements as those described above with reference to the previous drawings are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate. In the following description, for convenience of explanation, an XYZ orthogonal coordinate system may be used. In this coordinate system, two directions parallel to the surface of the semiconductor substrate and perpendicular to each other are defined as an X direction and a Y direction, and a direction perpendicular to both the X direction and the Y direction is defined as a Z direction. And In the bonding apparatus, two directions that are parallel to the stage moving surface and are orthogonal to each other are defined as an X direction and a Y direction, and a direction perpendicular to both the X direction and the Y direction is defined as a Z direction. To do.

(Embodiment)
Hereinafter, embodiments will be described with reference to FIGS. FIG. 1 is an example of a configuration diagram of a wire bonding apparatus 50 used in the present embodiment. The wire bonding apparatus 50 is an apparatus that uses the wedge tool 34 as a wire bonding tool and forms wire bonding that connects a plurality of bonding objects by a wedge bonding method. In the embodiment of the present invention, the wedge bonding method is one method of wire bonding, and uses pressure (pressure welding) and energy by ultrasonic vibration without forming FAB (Free Air Ball) at the wire tip. This means a bonding method in which a wire is bonded to a pad or the like.

  As shown in FIG. 1, the wire bonding apparatus 50 includes a gantry 52, a bonding stage 54 and an XY stage 56 held on the gantry 52, and a computer 100. The bonding stage 54 is a bonding object holding table on which the semiconductor chip 10 as a bonding object and the circuit board 14 are placed. FIG. 1 shows a state in which a semiconductor chip 10 as a bonding object and a circuit board 14 are placed.

  The bonding stage 54 is movable with respect to the gantry 52 when the circuit board 14 or the like is placed or discharged. The bonding stage 54 is fixed to the gantry 52 during the bonding process. For example, a metal moving table can be used as the bonding stage 54. The bonding stage 54 is connected to a reference potential such as the ground potential of the wire bonding apparatus 50, for example. When insulation between the semiconductor chip 10 and the circuit board 14 is necessary, an insulation process can be performed on a necessary portion of the bonding stage 54.

  The semiconductor chip 10 is an electronic circuit in which transistors and the like are integrated on a silicon substrate. On the upper surface of the semiconductor chip 10, input terminals and output terminals as electronic circuits are drawn out as a plurality of pads. The lower surface of the semiconductor chip 10 is the back surface of the silicon substrate and serves as a ground electrode for an electronic circuit.

  For example, the circuit board 14 is obtained by patterning desired wiring on an epoxy resin substrate. The circuit board 14 is a chip pad for electrically and mechanically connecting and fixing the lower surface of the semiconductor chip 10, a plurality of leads arranged around the chip pad, and a circuit board drawn out from the chip pad and the plurality of leads. It has an input terminal and an output terminal. Wire bonding is performed by connecting a pad on the semiconductor chip 10 and a lead on the circuit board 14 with a wire.

  The wind clamper 68 is provided on the bonding stage 54. The wind clamper 68 is a flat plate member having an opening at the center, and is used to hold the circuit board 14. The wind clamper 68 is positioned so as to be disposed in the lead of the circuit board 14 and the semiconductor chip 10 and the central opening, and holds the circuit board 14 at the peripheral edge of the opening, thereby holding the circuit board 14 in the bonding stage. 54 is fixed.

  The XY stage 56 has a bonding head 58 mounted thereon. The XY stage 56 is a moving table that moves the bonding head 58 to a desired position in the XY plane. The XY plane is a plane parallel to the upper surface of the gantry 52. The Y direction is a direction parallel to the longitudinal direction of the ultrasonic transducer 64 attached to a bonding arm (not shown) described later.

  The bonding head 58 is fixedly mounted on the XY stage 56. The bonding head 58 incorporates a Z motor 60. The bonding head 58 is a moving mechanism that is controlled to move by driving the Z motor 60 and moves the wedge tool 34 in the Z direction via the Z driving arm 62 and the ultrasonic transducer 64. As the Z motor 60, for example, a linear motor can be used.

  The Z drive arm 62 includes an ultrasonic transducer 64 and a wire clamper 70. The base of the ultrasonic transducer 64 is attached to the Z drive arm 62. A wedge tool 34 for inserting the wire 18 is attached to the tip of the ultrasonic transducer 64. An ultrasonic transducer 66 is attached to the ultrasonic transducer 64. The ultrasonic transducer 64 transmits ultrasonic energy generated when the ultrasonic transducer 66 is driven to the wedge tool 34. As the ultrasonic transducer 66, for example, a piezoelectric element can be used.

  The wire 18 is wound around a wire spool 72 provided at the tip of a wire holder extending from the bonding head 58. The wire 18 is inserted from the wire spool 72 through the wire clamper 70 into the through hole of the wedge tool 34 and protrudes from the tip of the wedge tool 34.

  The wire clamper 70 is a set of sandwich plates that are attached to the Z drive arm 62 and disposed on both sides of the wire 18. The wire 18 can be freely extended by opening the gap between the opposing sandwich plates, and the extension of the wire 18 can be stopped by closing the gap between the opposite sandwich plates.

  The computer 100 controls the operation of each element of the wire bonding apparatus 50 as a whole. The computer 100 includes a control unit 76 that is a CPU, various interface circuits, and a memory 78. These are connected to each other by an internal bus 96.

  The various interface circuits are drive circuits or buffer circuits provided between the control unit 76, which is a CPU, and each element of the wire bonding apparatus 50. In FIG. 1, the interface circuit is expressed as I / F. The computer 100 includes, as various interface circuits, an XY stage I / F 102 connected to the XY stage 56, a Z motor I / F 104 connected to the Z motor 60, and an ultrasonic transducer I / F connected to the ultrasonic transducer 66. F 106 and a clamper opening / closing I / F 108 connected to the clamper opening / closing unit 74.

  The memory 78 is a storage device that stores various programs and various control data. The various programs are a first bonding program 80 related to the first wire bonding process, a second bonding program 82 related to the second wire bonding process, a third bonding program 84 related to the third wire bonding process, and a looping control program 86 related to the looping control. A control program 92 relating to other control processing. The memory 78 has control data 94 used in the various programs.

  FIG. 2 is an example of a plan view (viewed from above) schematically showing an outline of wire bonding in the semiconductor device according to the present embodiment, and shows a part of the semiconductor chip 10 and the circuit board 14. As shown in FIG. 2, the circuit board 14 has leads 16 (pads) on the top thereof. The leads 16 on the circuit board 14 are formed using a conductive material such as gold (Au), copper (Cu), and aluminum (Al).

  The semiconductor chip 10 is mounted on the circuit board 14. Pads 12 are formed on the semiconductor chip 10. In the figure, the lower right portion of the semiconductor chip 10 is shown. In the figure, the upper left corner is the central portion of the semiconductor chip 10. The pad 12 is formed using, for example, aluminum (Al). The pad 12 and the lead 16 are connected using a wire 18. The wire 18 is formed using a conductive material such as gold (Au), copper (Cu), and aluminum (Al).

  The wire 18 is bonded to the pad 12 and the lead 16 by a wedge bonding method. The plurality of pads 12 are arranged in a row at intervals in a direction parallel to one side of the semiconductor chip 10 (Y direction in the drawing, hereinafter sometimes referred to as a first direction). The pad 12 has a rectangle having a longitudinal direction in a direction perpendicular to the first direction (X direction in the drawing, hereinafter sometimes referred to as a second direction). The plurality of pads 12 are arranged in the first direction with their short sides facing each other.

  The leads 16 formed on the circuit board 14 are arranged at a larger interval than the pads 12. The leads 16 are opposed to the pads 12 and are arranged in the first direction. Each lead 16 has a rectangular shape having a longitudinal direction in a direction along the line connecting the lead 16 and the pad 12 (hereinafter sometimes referred to as a third direction).

  The angle formed by the longitudinal direction (second direction) of the pad 12 and the direction of the line connecting the pad 12 and the lead 16 (third direction) is from the pad 12 located at the center of the semiconductor chip 10 (right end in the drawing) to the semiconductor chip 10. It becomes large toward the pad 12 located at the end (left end in the figure). This is because the pads 12 are closely spaced and closely arranged, whereas the leads 16 are spaced larger than the pads 12.

  The longitudinal direction of the pad 12 (second direction, direction of a line 32 to be described later) and the direction of a line connecting the pad 12 and the lead 16 (third direction, direction of a line 30 to be described later) may not coincide with each other. . The semiconductor chip 10 is required to be formed with a small area. Therefore, the pattern formed on the semiconductor chip 10 is laid out so as to be filled as densely as possible. In recent years, with the advancement of functions of the semiconductor chip 10, many pads 12 are formed. Accordingly, the pads 12 on the semiconductor chip 10 are formed short in the arrangement direction so that the pads 12 can be densely laid out on the semiconductor chip 10 and many pads 12 can be formed. Therefore, the pad 12 may be a rectangle having a short side in the arrangement direction. Further, in order to lay out as many pads 12 as possible within a limited area on the semiconductor chip 10, the distance between adjacent pads 12 is made as small as possible so that the longitudinal direction of the pads 12 is the same direction. It is arranged to be. Therefore, it is difficult to dispose the pad 12 at an angle so that the longitudinal direction thereof coincides with the direction of the line connecting the lead 16. Therefore, the longitudinal direction (second direction) of the pad 12 and the direction of the line connecting the pad 12 and the lead 16 (third direction) often do not coincide with each other. The angle formed by the three directions increases.

  Next, in the present embodiment, an example of a process procedure for bonding the wire 18 to the surface of the pad 12 and the lead 16 using the wedge bonding method will be described. First, the wedge tool 34 used for the wedge bonding method in this embodiment will be described.

  In FIG. 4, an example of the longitudinal cross-sectional view for demonstrating the structure of the wedge tool 34 typically is shown. FIG. 4 is a longitudinal sectional view of the wedge tool 34 in a direction along the direction of the through hole 38 for inserting the wire 18. The wedge tool 34 has a through hole 38 through which the wire 18 passes. The through hole 38 is formed, for example, so as to penetrate the wedge tool 34 from the rear to the bottom (lower part) of the wedge tool 34. The wedge tool 34 has a pressing surface 36 at the bottom. At the time of bonding, as indicated by an arrow in the drawing, the wire 18 is supplied to the through hole 38 from the rear of the wedge tool 34, passes from the tip of the through hole 38 to the bottom of the wedge tool 34, and passes under the pressing surface 36. , Projecting laterally forward. This protruding portion becomes a tail 20 during bonding, as shown in FIGS. 3A to 3C and FIGS.

  As described above, the direction from the pressing surface 36 through the through hole 38 and toward the rear of the wedge tool 34 is the bonding direction of bonding and the moving direction of the wedge tool 34 during wedge bonding. That is, the wedge tool 34 has a specific joining direction and moving direction. Therefore, during wedge bonding using the wedge tool 34, the wedge tool 34 is rotated or the circuit board 14 is rotated in order to make the direction of the wedge tool 34 coincide with the bonding direction.

  3 (a) to 3 (c) and FIGS. 5 (a) to 5 (e) are diagrams for explaining the sequence of connecting (bonding) between the pad 12 and the lead 16 by the wire 18 step by step in order of steps. It is an example of a figure. FIG. 6 is an example of a flowchart showing the procedure of the wire bonding method. Each procedure of the wire bonding method corresponds to the procedure of each program stored in the memory 78 of the computer 100 and is controlled by the control unit 76. Hereinafter, description will be made with reference to FIGS. 3A to 3C, FIGS. 5A to 5E, FIG. 6 and FIG. In the present embodiment, the wire 18 is first bonded to the pad 12 (first connection region) on the semiconductor chip 10 and then bonded to the lead 16 (second connection region) on the circuit board 14.

  First, the circuit board 14 on which the semiconductor chip 10 to be bonded is mounted is positioned and set on the bonding stage 54 and fixed by the wind clamper 68. The bonding stage 54 is located at the initial position. The wire 18 is supplied to the through hole 38 of the wedge tool 34 obliquely from the rear of the wedge tool 34. The tip of the wire 18 projects a predetermined length from the tip of the wedge tool 34. As described above, this protruding portion later becomes the tail 20.

  Next, the first bonding program 80 is executed by the control unit 76. With the first bonding program 80, the control unit 76 outputs a signal (command) for forming the first bonding point 25 on the pad 12. By this command, signals from the XY stage I / F 62 and the Z motor I / F 64 are output to the XY stage 56 and the Z motor 60, and the wedge tool 34 is moved above the position where the first joint point 25 of the pad 12 is formed. (S101).

  The formation position of the first junction point 25 is set on the pad 12 of the semiconductor chip 10 and is set to the upper position in the X direction in FIG. 3A and is stored in the control data 94 as coordinate data. . Precise position control of the wedge tool 34 is performed using a positioning camera or the like (not shown).

  Next, signals (commands) from the XY stage I / F 62 and the Z motor I / F 64 are output to the XY stage 56 and the Z motor 60, and the direction of the wedge tool 34 is changed to the second direction (X direction in the figure). Adjustment is made so as to face (S102). Next, signals (commands) from the XY stage I / F 62 and the Z motor I / F 64 are output to the XY stage 56 and the Z motor 60, and the wedge tool 34 is lowered to the surface of the pad 12.

  In the pad 12, the wire 18 is sandwiched between the pressing surface 36 of the wedge tool 34 and the pad 12 at the position where the first joint point 25 is to be formed, and the wire 18 is pressed against the surface of the pad 12. Next, a signal (command) from the ultrasonic transducer I / F 106 is output to the ultrasonic transducer 66 to operate the ultrasonic transducer 66. Thereby, ultrasonic vibration is applied to the pressing surface 36. The wire 18 is bonded to the pad 12 by the ultrasonic vibration energy applied to the pressing surface 36 and the pressing force by the drive control of the Z motor 60. Next, signals (commands) from the XY stage I / F 62 and the Z motor I / F 64 are output to the XY stage 56 and the Z motor 60, and the wedge tool 34 is moved in a direction in which the pressing surface 36 is away from the first joint point 25. Raise.

  In this way, as shown in FIGS. 3A and 5A, the first wire bonding process is performed, and the first bonding point 25 is formed on the pad 12 (S103). As shown in FIG. 3A and the like, the joining surface of the first joining point 25 has a substantially elliptical shape in plan view, and its longitudinal direction (joining direction) is the same as the line 32 (second direction). Direction). Further, since the tail 20 extends in the second direction (X direction in the drawing), the possibility of contacting the adjacent pad 12 is very low.

  Next, the second bonding program 82 is executed by the control unit 76. With the second bonding program 82, the control unit 76 outputs a command for forming the second bonding point 26 on the lead 16. By this command, signals from the XY stage I / F 62 and the Z motor I / F 64 are output to the XY stage 56 and the Z motor 60, and the wedge tool 34 is moved above the second joint 26 in the lead 16 (S104). ).

  The position of the second junction point 26 is set on the chip end side of the first junction point 25 on the pad 12 (pad 12), and is stored in the control data 94 as coordinate data. Precise position control of the wedge tool 34 is performed using a positioning camera or the like (not shown).

  Further, signals from the XY stage I / F 62 and the Z motor I / F 64 are output to the XY stage 56 and the Z motor 60, and the direction of the wedge tool 34 is adjusted to face the third direction (S105). Thereby, the wedge tool 34 faces substantially the same direction as the line 30 (third direction). The orientation of the wedge tool 34 may be adjusted after moving the wedge tool 34 above the second joint point 26 as well as after moving the wedge tool 34 above the second joint point 26.

  Next, signals from the XY stage I / F 62 and the Z motor I / F 64 are output to the XY stage 56 and the Z motor 60, the wedge tool 34 is lowered to the surface of the lead 16, and the wire 18 is second joined to the surface of the lead 16. The point 26 is pressed to the planned formation position. At the position where the second joining point 26 is to be formed, the wire 18 is sandwiched between the pressing surface 36 of the wedge tool 34 and the pad 12, and the wire 18 is pressed against the surface of the lead 16.

  Next, a signal from the ultrasonic transducer I / F 106 is output to the ultrasonic transducer 66 to operate the ultrasonic transducer 66. Thereby, ultrasonic vibration is applied to the pressing surface 36. The wire 18 and the pad 12 are joined by the ultrasonic vibration energy applied to the pressing surface 36 and the pressing force by the drive control of the Z motor 60. In this way, as shown in FIGS. 3B and 5B, the second wire bonding process is performed on the pad 12 to form the second bonding point 26 (S106).

  As shown in FIG. 3B, the joint surface of the second joint point 26 has an elliptical shape in plan view, and its longitudinal direction (joint direction) is substantially the same as the line 30 connecting the pad 12 and the lead 16. The same direction (third direction).

  The accuracy of the direction of the wedge tool 34 or the longitudinal direction of the second joining point 26 depends on the accuracy of the wire bonding apparatus 50, and exactly matches the same direction as the line 30 (that is, the third direction). Not necessarily. Further, since the accuracy may vary depending on the apparatus, the amount of deviation is not constant. That is, the direction of the wedge tool 34 or the longitudinal direction of the second joining point 26 may be larger or smaller than the angle θ formed by the line 32 and the line 30. Moreover, although the joining shape of the joining points 25, 26, and 27 has a substantially elliptical shape, the longitudinal direction may vary depending on how the wire 18 is crushed.

  Accordingly, the direction of the wedge tool 34 or the longitudinal direction of the second joining point 26 is a direction from the direction of the line 32 (second direction) toward the direction of the line 30 (third direction), and from the line 32 to the direction of the line 30. It means only the direction in which an arbitrary angle is rotated, and does not mean exactly the same direction as the direction of the line 30 (third direction). For the same reason, the direction of the wedge tool 34 or the longitudinal direction of the first joint point 25 intersects the direction of the line 32 (second direction) in a range where the tail 20 does not contact the adjacent pad 12. Alternatively, it only means the same direction as the direction of the line 32 (second direction), and does not mean strictly limited to the same direction as the direction of the line 32 (second direction).

  Subsequently, as shown in FIGS. 5C and 5D, the looping control program 86 is executed by the control unit 76. By the looping control program 86, the control unit 76 operates the wedge tool 34 to start the third joint on the lead 16 (second connection area) from the second joint point 26 on the pad 12 (first connection area). A signal (command) for forming a loop shape (arc shape) of the wire 18 is output toward the point 27 direction. In response to this command, signals from the XY stage I / F 102, the Z motor I / F 104, and the clamper opening / closing I / F 108 are output to the XY stage 56, the Z motor 60, and the wire clamper 70. Then, as shown in FIG. 5C, the wire bonding apparatus 50 is driven to raise the wedge tool 34 upward with the wire clamper 70 opened.

  Next, signals from the XY stage I / F 102 and the Z motor I / F 104 are output to the XY stage 56 and the Z motor 60. As a result, the XY stage 56 and the Z motor 60 are driven to move, so that the wedge tool 34 is moved toward the formation planned position of the third joint point 27 in the lead 16. The planned formation position of the third junction point 27 is set on the lead 16 on the circuit board 14 and stored in the control data 94 as coordinate data.

  During the movement of the wedge tool 34 to the position where the third junction point 27 is to be formed, the wire 18 is unwound from the wire spool 72 and extended from the tip of the wedge tool 34 by the required wire length. Thereby, as shown in FIGS. 5D and 5E, the wire 18 is stretched so as to draw a loop shape (arc shape) toward the third joint point 27 while being plastically deformed (this is shown in FIG. (Referred to as looping) (S107).

  At this time, since the wire 18 is pulled by the wedge tool 34 in accordance with the movement of the wedge tool 34, a tensile stress is generated at the second joining point 26 via the wire 18. Thereafter, the wedge tool 34 moves above the position where the third joint point 27 is to be formed while looping (S108).

  Next, the third bonding program 84 is executed by the control unit 76. With the third bonding program 84, the control unit 76 outputs a signal (command) for forming the third bonding point 27 on the lead 16. At this time, the wedge tool 34 is directed in the direction of the line 30 (third direction). The lead 16 (pad) has a rectangular shape, and its longitudinal direction faces the direction of the line 30 (third direction).

  Next, signals from the XY stage I / F 62 and the Z motor I / F 64 are output to the XY stage 56 and the Z motor 60, the wedge tool 34 is lowered to the surface of the lead 16, and the wire 18 is connected to the third joint on the lead 16. The point 27 is pressed to the planned formation position. Thereby, in the lead 16, the wire 18 is sandwiched between the pressing surface 36 of the wedge tool 34 and the lead 16, and the wire 18 is pressed against the surface of the lead 16.

  Next, a signal from the ultrasonic transducer I / F 106 is output to the ultrasonic transducer 66 to operate the ultrasonic transducer 66. Thereby, ultrasonic vibration is applied to the pressing surface 36. The wire 18 and the lead 16 are joined by the ultrasonic vibration energy applied to the pressing surface 36 and the pressing force by the drive control of the Z motor 60. In this way, the third wire bonding process is performed on the lead 16, and the third bonding point 27 is formed as shown in FIGS. 3C and 5E (S109).

As shown in FIG. 3C, the joint surface of the third joint point 27 has an elliptical shape in plan view, and its longitudinal direction (joint direction) is substantially the same direction as the line 30, that is, the first It faces 3 directions.
For the same reason as the reason for the accuracy of the direction of the wedge tool 34 or the longitudinal direction of the second joint point 26, the direction of the wedge tool 34 or the longitudinal direction of the third joint point 27 is the direction of the line 32 (second direction). ) Means a direction toward the direction of the line 30 (third direction), a direction rotated by an arbitrary angle from the line 32 to the direction of the line 30, and strictly refers to the direction of the line 30 (third direction). It does not mean the same direction.

  Next, signals from the XY stage I / F 62, the Z motor I / F 64 and the clamper opening / closing I / F 108 are output to the XY stage 56, the Z motor 60 and the wire clamper 70. Thereby, the wire 18 is clamped and pulled while the wedge tool 34 is fixed, and the wire 18 is cut behind the third joint point 27 (S110). As described above, the wire bonding according to the present embodiment can be formed.

  Here, for example, two bonding points having different longitudinal directions (bonding directions) such as the first bonding point 25 and the second bonding point 26 described above are not provided on the pad 12, and FIG. ), A case is assumed in which one joining point 40 is formed in which the longitudinal direction (joining direction) faces the direction connecting the pad 12 and the lead 16 (line 30 direction).

  In this case, since the wire 18 faces the direction of the line 30, the tip of the tail 20 projects in the direction of the adjacent pad 12. Since the distance between the adjacent pads 12 is small, the tail 20 may come into contact with the adjacent pads 12 and a short circuit 42 may occur between the adjacent pads 12.

  In the present embodiment, since the longitudinal direction (joining direction) of the first joining point 25 is oriented in the longitudinal direction (line 32 direction, X direction in the drawing) of the pad 12, the tail 20 is also oriented in the line 32 direction. . Therefore, the possibility that the tail 20 contacts the adjacent pad 12 is very small. As a result, the possibility of a short circuit between adjacent pads 12 is extremely small.

  Further, for example, two bonding points having different longitudinal directions (bonding directions) such as the first bonding point 25 and the second bonding point 26 described above are not provided on the pad 12, and FIG. As shown in FIG. 4, a case is assumed where one joining point 40 is formed in which the longitudinal direction (joining direction) faces the longitudinal direction of the pad 12 (line 32 direction, X direction in the drawing). In this case, the longitudinal direction of the junction point 40 is directed in the direction of the line 32.

  When looping is performed in this state, the tensile force applied when forming the loop of the wire 18 is applied in the direction of the line 30, but the joining direction of the joining point 40 and the direction in which the tensile force by the wire 18 is applied are different. Therefore, since the stress is concentrated on the neck 44 on one side of the end of the joining point 40 due to the pulling force by the wire 18, damage (crack) may occur in this portion, and open (disconnection) failure may occur.

  In the present embodiment, the longitudinal direction (bonding direction) of the second bonding point 26 is directed to the direction connecting the pad 12 and the lead 16 (line 30 direction, third direction). Therefore, the stress applied when forming the loop of the wire 18 does not concentrate on the neck. Therefore, the occurrence of cracks at this location is suppressed, and the possibility of occurrence of an open (disconnection) failure of the wire 18 is extremely small.

  As described above, according to the present embodiment, the pad 12 on the semiconductor chip 10 has the first junction point 25 and the second junction point 26. Since the longitudinal direction (joining direction) of the first joining point 25 is oriented in the longitudinal direction of the pad 12, that is, the line 32 direction, the tail 20 is also oriented in the line 32 direction. That is, the tail 20 does not face the adjacent pad 12 direction. Thereby, it is possible to suppress the tail 20 from coming into contact with the adjacent pads 12, and it is possible to suppress the occurrence of a short circuit between the adjacent pads 12.

  In the present embodiment, the longitudinal direction (bonding direction) of the second bonding point 26 faces the lead 16 on the circuit board 14 (third bonding point 27 on the lead 16). Thereby, it becomes possible to suppress the occurrence of cracks due to the stress applied during the looping of the wire 18 at the neck at the end of the second joint point 26, and the occurrence of an open failure of the wire 18 can be suppressed.

  That is, by applying the present embodiment, while preventing a short circuit between pads due to the contact of the tail 20 of the wire 18, damage to the wire neck at the bonding junction is suppressed, thereby suppressing the wire open, and consequently the yield of wire connection. It becomes possible to improve.

(Other embodiments)
The embodiment described above can be applied to various semiconductor devices. For example, the present invention may be applied to NAND-type or NOR-type flash memory, EPROM, DRAM, SRAM, other semiconductor memory devices, various logic devices, and other semiconductor devices.

  Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  In the drawing, 10 is a semiconductor chip, 12 is a pad, 14 is a circuit board, 16 is a lead, 18 is a wire, 20 is a tail, 25 is a first junction point, 26 is a second junction point, 27 is a third junction point, Reference numeral 34 denotes a wedge tool, 36 denotes a pressing surface, 38 denotes a through hole, 50 denotes a wire bonding apparatus, 76 denotes a control unit, and 100 denotes a computer.

Claims (5)

A circuit board;
A semiconductor chip mounted on the circuit board,
The semiconductor chip has a rectangular shape on its upper surface, and has at least two bonding pads serving as a first connection region, arranged in a first direction so that their long sides face each other,
The circuit board has at least two bonding leads serving as second connection regions arranged in the first direction,
The first connection region and the second connection region corresponding to the first connection region are formed by wire bonding by a wedge bonding method, using the first bonding point, the second bonding point, and the third bonding point. Connected,
The first and second junction points have a substantially elliptical shape, and are formed on the first connection region and arranged in a second direction perpendicular to the first direction,
The third junction point has a substantially oval shape and is formed on the second connection region;
The longitudinal direction of the first joining point is directed to the second direction,
When the direction connecting the second joint point and the third joint point is the third direction, the longitudinal direction of the second joint point is directed to the third direction from the second direction. A semiconductor device characterized by comprising:   The semiconductor device according to claim 1, wherein a longitudinal direction of the second junction point is parallel to the third direction.   The semiconductor device according to claim 1, wherein a longitudinal direction of the second junction point is the same as a longitudinal direction of the third junction point. A stage on which a circuit board on which a semiconductor chip is mounted can be placed;
A bonding arm to which a tool for bonding by the wedge bonding method can be attached;
A control unit for controlling the operation of the tool,
On the semiconductor chip, a plurality of elements are arranged in a first direction, each has a rectangular shape, and a longitudinal direction thereof has a first connection region facing a second direction perpendicular to the first direction,
On the circuit board, each has a rectangular shape, and a longitudinal direction thereof is a second direction facing a direction of a line connecting the first connection region and the second connection region (hereinafter referred to as a second direction). Has a connection area,
The control unit moves the tool onto a first joint point in the first connection region, forms the first joint point by a wedge bonding method, and moves the tool in the first connection region. When the second direction is moved along the second direction onto the second junction point adjacent to the first junction point, and the direction connecting the first connection region and the second connection region is the third direction. In addition, the tool is controlled so as to be directed in the third direction rather than the second direction, a second bonding point is formed by a wedge bonding method, and the tool is directed in the direction. A wire bonding apparatus that performs control to form a third joint point by moving the third joint point in the second connection region while looping in a state. The wire bonding apparatus according to claim 4, wherein the second joining point has a substantially elliptical shape, and a longitudinal direction thereof is parallel to the third direction.

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