JP6182248B2 - Die bonder - Google Patents

Description

  The present invention relates to a structure of a die bonder and a method for detecting a relative position between a bonding tool and a semiconductor die adsorbed on the tip of the bonding tool.

  A die bonder is often used as an apparatus for bonding a semiconductor die to a circuit board such as a lead frame. The die bonder lowers the semiconductor die sucked and held at the tip of the bonding tool toward the surface of the circuit board sucked and fixed on the bonding stage, and bonds the semiconductor die onto the circuit board.

  In the die bonder, it is necessary to press the semiconductor die against the circuit board in a state where the position of the semiconductor die attracted by the bonding tool is matched with the bonding position of the circuit board. For this reason, when the semiconductor die is transferred by the bonding tool, an image of the back surface of the semiconductor die attracted by the bonding tool is acquired, and the relative position of the semiconductor die and the circuit board is aligned based on the alignment mark on the back surface of the semiconductor die. The method is used (for example, refer patent document 1).

  However, in the method described in Patent Document 1, it is necessary to temporarily stop the transfer of the semiconductor die when acquiring an image, and there is a problem that the tact time becomes long. Therefore, a reference member having a mirror and a rectangular through hole is fixed to the transfer head of the semiconductor die via an L-shaped connecting member, and when the semiconductor die is transferred by the transfer head, the transfer is temporarily stopped. The first image data obtained by imaging the semiconductor die and the second image data obtained by imaging the reference component are obtained, and the position of the semiconductor die with respect to the reference component is detected by superimposing the two image data. A method of correcting the position of the semiconductor die mounted on the circuit board in response to the above has been proposed (see, for example, Patent Document 2).

JP 2010-40738 A JP 2007-115851 A

  By the way, in the prior art described in Patent Document 2, since it is necessary to arrange the reference member at a position that does not hinder bonding, the semiconductor adsorbed on the optical path from the reference member to the camera and the tip of the transfer head It is necessary to make the optical path to the die a different optical path. On the other hand, in order to simultaneously capture the image of the reference member and the image of the semiconductor die attracted to the tip of the transfer head, it is necessary to configure the optical path so that the two optical paths are combined into one. It is also necessary to make the optical path length from the reference member to the camera equal to the optical path length from the surface of the semiconductor die to the camera so that the image of the reference member and the semiconductor die is in focus. For this reason, it is necessary to use many half mirrors and prisms in the optical system, and there is a problem that the configuration of the optical system becomes complicated.

  Further, in the prior art described in Patent Document 2, since the reference member is attached to the transfer head by the connecting member, the reference component vibrates due to the reciprocating movement of the transfer head, and the detection error caused by this causes the detection of the semiconductor die. There has been a problem that misalignment may occur (see Patent Document 2, paragraph 0096).

  Accordingly, an object of the present invention is to detect a positional deviation between a bonding tool and a semiconductor die effectively with a simple configuration.

The die bonder of the present invention is a bonding having an adsorption surface for adsorbing a semiconductor die at the tip, a base thicker than the adsorption surface at the tip, and an inclined surface connecting the adsorption surface and the root and inclined with respect to the longitudinal center line. has a tool, substantially parallel reflecting surfaces and suction surfaces, a grip portion for gripping the root source is disposed below the suction surface, a light source for projecting the suction surface is located below the suction surface, inclined The black circular image of the surface, the white ring-shaped image of the reflecting surface adjacent to the outer periphery of the circular image of the inclined surface, and the white image of the lower surface of the semiconductor die located in the circular image of the inclined surface are the same A camera that captures the field of view, a black circular image of the inclined surface captured by the camera, a white ring-shaped image of the reflective surface adjacent to the outer periphery of the circular image of the inclined surface, and a circular image of the inclined surface captured image including a lower surface white image of the semiconductor die located An image processing unit that performs image processing on the image, and the image processing unit has a second corresponding to the first outer shape reference line and the edge of the semiconductor die with respect to the outer periphery of the inclined surface with respect to the captured image captured by the camera. It has an outline setting means for setting an outline reference line.

In the die bonder of the present invention , the image processing unit calculates the first center coordinate on the first outer shape reference line and the second center coordinate on the second outer shape reference line, and the difference between the first and second center coordinates. And a deviation amount detecting means for detecting the deviation amount of the semiconductor die with respect to the bonding tool .

In the die bonder of the present invention, the image processing unit calculates an angle difference between the first outer shape reference line and the second outer shape reference line, and calculates a deviation amount of the rotation direction of the semiconductor die with respect to the bonding tool based on the angle difference. It is also preferable to include rotation amount detection means for detecting .

In the die bonder of the present invention, the camera is also preferable to have a depth of focus that focuses on the lower surface of the semiconductor die rather than the inclined surface and the reflective surface .

In the die bonder of the present invention , the outer shape setting means sets a first outer shape reference line corresponding to the outer periphery of the inclined surface and a second outer shape reference line corresponding to the edge of the semiconductor die using a predetermined binarization threshold. It is also suitable.

  The present invention has an effect that a positional deviation between a bonding tool and a semiconductor die can be detected effectively with a simple configuration.

It is a distribution diagram showing the composition of the control system of the die bonder in the embodiment of the present invention. It is explanatory drawing which shows the detail of the bonding tool and shank of the die bonder in embodiment of this invention. It is explanatory drawing which shows operation | movement of the die bonder in embodiment of this invention. It is explanatory drawing which shows the structure of the bonding tool and shank of the die bonder in embodiment of this invention, and the image caught with the camera. It is explanatory drawing which shows the process of binarizing the image shown in FIG. It is explanatory drawing which shows the image which binarized the image shown in FIG. It is explanatory drawing which shows the structure of the bonding tool and ring of the die bonder in other embodiment of this invention, and the image caught with the camera. It is explanatory drawing which shows the structure of the bonding tool of the die bonder in other embodiment of this invention, and the image caught with the camera.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a die bonder 10 of the present invention includes a bonding head 15 to which a bonding tool 24 is attached via a shank 20, a guide rail 11 for guiding the bonding head 15 in the Y direction, and the bonding head 15 in the Y direction. A Y-direction moving mechanism 13 for moving the guide rail 11 and the bonding head 15 in the X direction, a camera 32 provided below the bonding head 15, and a strobe 34 as a light source. An image processing unit 40 to which the camera 32 and the strobe 34 are connected, and a control unit 50 to which the X and Y direction moving mechanisms 12 and 13 are connected. The bonding tool 24 has an adsorption surface 27 that adsorbs the semiconductor die 30 at the tip, and the strobe 34 includes a reflecting mirror 35 that directs emitted light toward the bonding tool 24. The bonding head 15 includes a Z-direction moving mechanism 16 that moves the bonding tool 24 in the Z direction and a θ-direction moving mechanism 17 that rotates the bonding tool 24 in the θ direction. Are respectively connected to the control unit 50. The controller 50 moves the bonding tool 24 in the X, Y, Z, and θ directions by operating the moving mechanisms 12, 13, 16, and 17 in the X, Y, Z, and θ directions. It is configured. 1, the horizontal direction on the paper is the Y direction, the vertical direction of the paper is the Z direction, the vertical direction to the paper is the X direction, and the rotation direction around the Z axis is the θ direction.

  As shown in FIG. 1, the image processing unit 40 is a computer that includes a CPU 41 that internally processes signals and data, and a memory 42 that stores data and programs. The memory 42 stores therein an image acquisition program 43, a relative position detection program 44, and control data 45 described later. Further, the image processing unit 40 includes a camera interface 47 and a strobe interface 48 for connecting to the camera 32 and the strobe 34. Further, the image processing unit 40 includes a data bus interface 46 for performing data communication with the control unit 50 which is another computer. The CPU 41, the memory 42, the interfaces 47 and 48, and the data bus interface 46 are connected by a data bus 49 inside the image processing unit 40.

  As shown in FIG. 1, like the image processing unit 40, the control unit 50 is a computer that includes a CPU 51 that internally processes signals and data, and a memory 52 that stores data and programs, and a data bus interface 56. Are connected to the CPU 41 and the memory 42 of the image processing unit 40 via the communication line 60 and the data bus interface 46 of the image processing unit 40. The memory 52 stores therein a position control program 53, a correction program 54, and control data 55, which will be described later. In addition, the control unit 50 includes a moving mechanism interface 57 for connecting to the moving mechanisms 12, 13, 16, and 17 in the X, Y, Z, and θ directions. The CPU 51, the memory 52, the moving mechanism interface 57 and the data bus interface 56 are connected by a data bus 59 inside the control unit 50.

  The X, Y, Z, and θ moving mechanisms 12, 13, 16, and 17 of the die bonder 10 of the present embodiment are signals indicating the positions of the tip of the bonding tool 24 in the X, Y, Z, and θ directions, respectively. The control unit 50 obtains the position in the X, Y, Z, and θ directions of the tip of the bonding tool 24 from the signals of the moving mechanisms 12, 13, 16, and 17.

  As shown in FIG. 2, the bonding tool 24 connects the tip suction surface 27 that sucks the semiconductor die 30, the root 25 that is thicker than the tip suction surface 27, and the suction surface 27 and the root 25. And an inclined curved surface 26 that is an inclined surface inclined with respect to the line 90. The suction surface 27 at the tip is substantially the same size as the semiconductor die 30 and is a plane perpendicular to the longitudinal center line 90 of the bonding tool 24. For this reason, the back surface of the semiconductor die 30 attracted to the attracting surface 27 is also a plane perpendicular to the longitudinal center line 90 of the bonding tool 24.

  The base 25 of the bonding tool 24 is thicker than the suction surface 27 at the tip and is a cylindrical shape fixed to the shank 20, and the inclined curved surface 26 is a curved surface that spreads in a funnel shape from the suction surface 27 toward the root 25. Further, the shank 20 has a cylindrical shape in which the outer peripheral surface of the base 25 of the bonding tool 24 is fitted on the inner peripheral side, and the end surface 21 on the lower side or the suction surface 27 side is in the longitudinal direction of the bonding tool 24. Alternatively, the surface of the bonding tool 24 is a plane perpendicular to the longitudinal center line 90 and the surface thereof is mirror-finished. Since the shank 20 is engaged with the bonding tool 24, the shank 20 does not move relative to the bonding tool 24 and is disposed at a position adjacent to the root 25.

  As shown in FIG. 2, the camera 32 is focused on the back surface (the lower surface in the Z direction) of the semiconductor die 30 adsorbed by the bonding tool 24 when the bonding tool 24 moves to a predetermined position directly above. It is arranged so as to fit, and is adjusted so that a sharp image of the back surface of the semiconductor die 30 can be acquired. That is, the camera 32 is adjusted so that the optical path length L1 between the lens of the camera 32 and the back surface of the semiconductor die 30 becomes the focal length of the lens of the camera 32.

  On the other hand, as shown in FIG. 2, the inclined curved surface 26 of the bonding tool 24 and the end surface 21 of the shank 20 are arranged apart from the suction surface 27 that sucks the semiconductor die 30 in the longitudinal direction. The optical path lengths to the inclined curved surface 26 and the end surface 21 of the shank 20 are optical path lengths L2 and L3. On the other hand, since the focal depth D of the lens of the camera 32 is slightly longer than the thickness of the semiconductor die 30, the optical path lengths L2 and L3 are longer than the length obtained by adding the focal depth D to the optical path length L1, respectively. . For this reason, when the image of the back surface of the semiconductor die 30, the image of the inclined curved surface 26 of the bonding tool 24, and the image of the end surface 21 of the shank 20 are simultaneously acquired by the camera 32, the inclined curved surface 26 of the bonding tool 24 and the end surface of the shank 20. 21 is in an out-of-focus state, and the acquired image of the inclined curved surface 26 and the image of the end surface 21 are slightly blurred images.

  Next, the operation of the die bonder 10 of this embodiment will be described. As shown in FIG. 3, the control unit 50 of the die bonder 10 executes a position control program 53 to drive the moving mechanisms 12, 13, 16, 17 in the X, Y, Z, and θ directions to move the top of the pickup stage 36. The bonding tool 24 is moved onto the diced wafer placed on the semiconductor wafer 30 and the semiconductor die 30 is sucked onto the suction surface 27 at the tip of the bonding tool 24. Then, the bonding head 15 is moved onto the bonding stage 37 as shown by a locus 38 shown in FIG. 3, the bonding head 15 is lowered onto the circuit board that is sucked and fixed onto the bonding stage 37, and the semiconductor die 30 is moved. Bond on the circuit board. This is the basic operation of the die bonder 10.

  The CPU 51 of the control unit 50 executes the position control program 53 and moves the bonding tools 24 from the pickup stage 36 to the bonding stage 37 while the X, Y, Z, and θ moving mechanisms 12, 13, 16, and 17 are moved. The position of each of the X, Y, Z, and θ directions of the tip of the bonding tool 24 is detected from the signal, and the bonding tool 24 comes to a predetermined position directly above the camera 32 as shown in FIG. When the longitudinal center line 90 of the bonding tool 24 is aligned with the center position of the lens, a trigger signal for causing the strobe 34 to emit light is output. This trigger signal is transmitted to the image processing unit 40 through the data bus interfaces 56 and 46 and the communication line 60. The predetermined position is a position set in the position control program 53 in advance.

  When this trigger signal is input, the CPU 41 of the image processing unit 40 executes the image acquisition program 43. The CPU 41 outputs a command for causing the strobe 34 to emit light. In response to this command, a flash signal is output from the flash interface 48 to the flash 34, and the flash 34 emits light. Further, when the trigger signal is input, the image processing unit 40 captures an image from the camera 32 through the camera interface 47 in synchronization with the light emission of the strobe 34. The captured image is stored in the memory 42 of the image processing unit 40. Note that the image is captured while the bonding tool 24 is moved (without stopping the movement).

  When the stroboscope 34 emits light, light from the stroboscope 34 from the suction surface 27 side of the bonding tool 24 as shown by arrows 71, 73, 75 shown in FIG. The light enters the back surface, the end surface 21 of the shank 20. A part of the light incident on the end face 21 of the shank 20 is in the longitudinal direction of the bonding tool 24 or in the direction along the longitudinal center line 90 of the bonding tool 24 (Z direction minus side) as indicated by an arrow 72 shown in FIG. ) And enters the camera 32 below the bonding tool 24 (on the suction surface 27 side), as shown in FIG. Therefore, in this embodiment, the shank 20 is a reflector, and the end surface 21 of the shank 20 is a reflecting surface. Further, a part of the light incident on the back surface or the lower surface (the surface on the negative side in the Z direction) of the semiconductor die 30 is, as indicated by an arrow 75 shown in FIG. The light is reflected in the direction along the longitudinal center line 90 of the bonding tool 24 (minus side in the Z direction) and enters the camera 32 on the lower side of the bonding tool 24 (on the suction surface 27 side).

  On the other hand, the light incident on the inclined curved surface 26 of the bonding tool 24 as shown by an arrow 73 in FIG. 4 is a direction different from the longitudinal direction of the bonding tool 24 such as the horizontal direction or the arrow 74 shown in FIG. The light is reflected in a direction different from the direction along the longitudinal center line 90 of the bonding tool 24.

  Then, as shown in FIG. 4B, in the visual field 33 of the camera 32, the lightness (white) ring-shaped image 81 (reflector) of the end face 21 where the light from the strobe 34 reflects toward the camera 32 is reflected. ), A low-lightness (black or gray) circular image 82 of the inclined curved surface 26 of the bonding tool 24 in which the light from the strobe 34 does not reflect toward the camera 32, and a strobe located in the circular image 82. A high-lightness (white) square image 84 of the back surface of the semiconductor die 30 in which light from 34 is reflected toward the camera 32 is captured. The image processing unit 40 simultaneously acquires these three images 81, 82, and 84 by the camera 32 and stores them in the memory 42. Note that an image 83 of the tip of the bonding tool 24 indicated by a broken line in FIG. 4B is hidden behind the image of the semiconductor die 30 and cannot be captured by the camera 32.

  As described above, since the focus of the camera 32 is adjusted to match the back surface of the semiconductor die 30, the image 84 on the back surface of the semiconductor die 30 is a sharp image. However, since the end surface 21 of the shank 20 and the inclined curved surface 26 of the bonding tool 24 are shifted in the Z direction from the back surface of the semiconductor die 30 to be larger than the focal depth D of the camera 32, the brightness of the end surface 21 is high (white). The ring-shaped image 81 and the low-intensity (black or gray) circular image 82 of the inclined curved surface 26 are blurred images.

  The CPU 41 of the image processing unit 40 executes a relative position detection program 44. In the following description, the brightness of the image will be described as 256 gradations (brightness 0 to brightness 255). As shown in FIG. 5A, the image acquired by the camera 32 includes a ring-shaped image 81 (reflector image) with a lightness of 255 on the end face 21 and a circular lightness with a lightness of 0 on the inclined curved surface 26 of the bonding tool 24. An image 82 (an image of an inclined surface) and a square image 84 of lightness 255 on the back surface of the semiconductor die 30 are included. As described above, the ring-shaped image 81 and the circular image 82 are blurred because the camera 32 is out of focus. Therefore, as shown in FIG. 5 (a), the brightness of the image 81 is 255 at the outer peripheral portion as shown by the line a. However, as the circular image 82 approaches, the brightness of the black image 82 increases. The part is mixed and the brightness gradually decreases as shown by the line b. Then, when entering the area of the image 82, the brightness rapidly decreases, and in the inner area of the image 82, the brightness is close to zero. Then, as indicated by the line c, the state of lightness 0 continues to the image 84 on the back surface of the semiconductor die 30. Since the camera 32 is focused on the back surface of the semiconductor die 30, the image 84 has a sharp outline. Further, since the back surface of the semiconductor die 30 reflects the light of the strobe 34, the lightness is 255. Accordingly, the brightness of the image rises almost vertically from the brightness 0 to the brightness 255 at the edge of the image 84, as indicated by the line d. In the region of the image 84, the brightness is constant at 255 as indicated by the line e.

  As shown in FIG. 5A, the CPU 41 of the image processing unit 40 uses a preset binarization threshold value, as shown in FIG. And the square outline reference line 92 of the image 84 are acquired. The binarization threshold is such that a circular line having a diameter substantially the same as the outer shape of the root 25 of the bonding tool 24 is a round outer reference of the image 82 when conditions such as the light state of the strobe 34 and the photographing position are reference conditions. It is determined in advance by a test or the like so that it can be acquired as the line 91. Since the image 81 and the image 82 are images of the inclined curved surface 26 of the bonding tool 24 and the end surface 21 of the shank 20 arranged concentrically, the change in brightness of each region indicated by the line a to the line e in FIG. The object is around the longitudinal center line of the tool 24. Therefore, even when conditions such as the light state of the strobe 34 and the photographing position deviate from the reference conditions, the change curve of the brightness between the image 81 and the image 82 is as shown by the alternate long and short dash line b ′ in FIG. Since the left and right objects (objects around the center line in the longitudinal direction of the bonding tool 24), the round outline reference line 91 ′ acquired using the binarization threshold shown in FIG. 5B is the root 25 of the bonding tool 24. It becomes a concentric circle with the outer shape of the bonding tool 24 having a diameter smaller than the outer shape. For this reason, even when conditions such as the light state of the strobe 34 and the photographing position deviate from the reference conditions, the centers of the round outline reference lines 91 and 91 ′ coincide with the position of the longitudinal center line of the bonding tool 24.

  Note that the back surface of the semiconductor die 30 is in focus, and the brightness changes almost vertically at the edge of the image 84. Therefore, even if the light condition of the strobe 34, the shooting position, etc. deviate from the reference condition, the image The size of 84 square outline reference lines 92 is almost the same.

  That is, in the present embodiment, the ring-shaped image 81 of the end face 21 that reflects the light of the strobe 34 has high brightness, and conversely, the circular image 82 of the inclined curved surface 26 that does not reflect the light of the strobe 34 has lightness. Is low and the brightness difference is very large. Therefore, the longitudinal positions of the bonding tool 24 of the end surface 21 and the inclined curved surface 26 are separated from the back surface of the semiconductor die 30 by the depth of focus D, and the brightness of the images 81 and 82 can be obtained even if a sharp image cannot be acquired. By utilizing the large difference, it is possible to reliably extract the circular outer shape reference line 91 concentric with the outer shape of the bonding tool 24. In addition, the square outline reference line 92 can be reliably extracted using the sharp edge of the image 84 on the back surface of the semiconductor die 30.

  As shown in FIG. 6, the image processing unit 40 detects the position of the center 97 of the circular outline reference line 91 and the position of the center 98 of the square outline reference line 92 from the processed image, and the circular outline reference line 91. An X-direction reference line 94 passing through the center 97 of the camera 32 and extending in the X direction of the field of view 33 of the camera 32, and a Y-direction reference line 93 passing through the center 97 of the circular outer shape reference line 91 and extending in the Y direction of the field of view 33 of the camera 32. Set. Further, the image processing unit 40 passes through the center 98 of the square outline reference line 92 and the X direction measurement line 96 and the center 98 of the square outline reference line 92 parallel to the side of the square outline reference line 92 close to the X direction reference line 94. A Y-direction measurement line 95 is set in parallel to a side of the street square outline reference line 92 close to the Y-direction reference line 93. Then, the image processing unit 40 obtains deviation amounts ΔX and ΔY in the X direction and the Y direction between the position of the center 97 of the circular outline reference line 91 and the position of the center 98 of the square outline reference line 92, respectively. The image processing unit 40 also calculates a square outline reference line from the angle difference in the θ direction between the X direction reference line 94 and the X direction measurement line 96 or the angle difference in the θ direction between the Y direction reference line 93 and the Y direction measurement line 95. The rotation angle deviation Δθ of 92 in the θ direction is detected.

  As described above, the circular outer shape reference line 91 is concentric with the outer shape line inside the end surface 21 of the shank 20 that is not displaced relative to the bonding tool 24, and the outer shape line of the bonding tool 24 is Since it is also a concentric circle, the position of the center 97 of the circular outline reference line 91 is the center position of the longitudinal center line 90 of the bonding tool 24 shown in FIG. 4A, and the square outline reference line 92 is the position of the semiconductor die 30. Since it is an edge of the outer shape, the center 98 of the square outer reference line 92 is the center position of the semiconductor die 30. Therefore, the deviation amounts ΔX and ΔY in the X and Y directions between the circular outer shape reference line 91 and the square outer shape reference line 92 are the X and Y direction differences between the center position of the bonding tool 24 and the center position of the semiconductor die 30. It becomes the amount of deviation.

  Similarly, an X-direction reference line 94 that passes through the center 97 of the circular outer shape reference line 91 and goes in the X direction of the visual field 33 of the camera 32, and passes through the center 97 of the circular outer shape reference line 91 in the Y direction of the visual field 33 of the camera 32. The heading Y-direction reference line 93 is a reference line on the suction surface 27 of the bonding tool 24, passes through the center 98 of the rectangular outer shape reference line 92, and is parallel to a side near the X-direction reference line 94 of the rectangular outer shape reference line 92. The Y-direction measurement line 95 passing through the center 98 of the square X-direction measurement line 96 and the square outline reference line 92 and parallel to the side close to the Y-direction reference line 93 of the square outline reference line 92 is on the suction surface 27 of the bonding tool 24. This is a line indicating the inclination angle of the semiconductor die 30 with respect to the reference line. Accordingly, the θ direction of the square outline reference line 92 obtained from the angle difference in the θ direction between the X direction reference line 94 and the X direction measurement line 96 or the angle difference in the θ direction between the Y direction reference line 93 and the Y direction measurement line 95. Is a tilt angle of the semiconductor die 30 with respect to the reference axis on the suction surface 27 of the bonding tool 24. The amount of deviation in the X and Y directions between the center position of the bonding tool 24 and the center position of the semiconductor die 30 and the inclination angle of the semiconductor die 30 with respect to the reference axis on the suction surface 27 of the bonding tool 24 are determined by bonding. The relative position between the tool 24 and the semiconductor die 30.

  When the image processing unit 40 detects the deviation amounts ΔX, ΔY, Δθ of the semiconductor die 30 with respect to the bonding tool 24 in the X, Y, θ directions, the data is transmitted to the control unit 50 through the data bus interfaces 46, 56 and the communication line 60. Send to. The CPU 51 of the control unit 50 executes the correction program 54 and detects the tip of the bonding tool 24 detected by each moving mechanism 12, 13, 16, 17 until the bonding tool 24 is moved to the bonding stage 37 shown in FIG. 3. Thus, the semiconductor die 30 can be bonded to the circuit board on the bonding stage 37 at an accurate position and direction by correcting the received positions by X, Y, and θ shift amounts ΔX, ΔY, and Δθ.

  As described above, the die bonder 10 according to the present embodiment has a brightness difference between the image 81 of the end surface 21 of the shank 20 holding the bonding tool 24 and the image 82 of the inclined curved surface 26 of the bonding tool 24. Since the center position of the longitudinal center line 90 of the bonding tool 24 and the center position of the semiconductor die 30 are detected using the difference in brightness between the image 84 of the back surface 30 and the image 82 of the inclined curved surface 26 of the bonding tool 24, the end surface 21. The inclined curved surface 26 deviates from the back surface of the semiconductor die 30 more than the depth of focus D, and the relative position between the bonding tool 24 and the semiconductor die 30 can be reliably detected even when the images 81 and 82 are not sharp. it can. For this reason, it is possible to detect the positional deviation of the semiconductor die effectively without using a complicated optical system with a simple configuration in which the end surface 21 of the shank 20 is mirror-finished to be a reflecting surface. Further, since the shank 20 holds the bonding tool 24 and does not move relative to the bonding tool 24, the movement of the bonding tool 24 is performed when images of the bonding tool 24, the shank 20, and the semiconductor die 30 are acquired. There is no need to stop and the tact time can be shortened. Further, since the shank 20 does not protrude from the bonding head 15, no vibration is generated by the movement of the bonding head 15, and the semiconductor die position shift can be detected effectively with a simple configuration.

  In the present embodiment, the inclined surface of the bonding tool 24 has been described as the funnel-shaped inclined curved surface 26, but the inclined surface is inclined with respect to the longitudinal center line 90 of the bonding tool 24, and from the strobe 34. Any shape may be used as long as it does not reflect light in the direction along the longitudinal center line 90. For example, it may be a tapered surface that obliquely connects the suction surface 27 and the root 25. .

  In the present embodiment, the positional deviation amount is detected during the bonding operation and corrected. However, the present invention is not limited to the correction during the bonding operation. In the previous training or teaching, the present invention can also be applied to the case where the positional deviation is measured in advance and the offset amount of the bonding tool 24 is set based on the result. In that case, when the image is acquired, the movement of the bonding tool 24 is stopped, and the inclined curved surface 26 of the bonding tool 24, the shank 20, the images 81, 82, and 84 of the semiconductor die 30 taken in a stationary state and the bonding tool. The shift amount and the offset amount may be set by combining the images 81, 82, and 84 acquired without stopping the movement of 24.

  In the present embodiment, the position of the bonding tool 24 is corrected based on the relative position between the bonding tool 24 and the semiconductor die 30 sucked on the suction surface 27 of the bonding tool 24. Using the position detection result of the longitudinal center line 90, the relative position between the bonding tool 24 and the pickup stage 36 or the bonding stage 37 is corrected, and the deviation amount of the pickup position or the bonding position due to the temperature change of the die bonder 10 is corrected. It is good also as correcting. In this case, for example, a moving average of the positional deviation between the bonding tool 24 and the pickup stage 36 or the bonding stage 37 is obtained, and the correction direction of the deviation amount is determined based on the tendency of the change of the moving average value. Also good.

  Next, another embodiment of the present invention will be described with reference to FIGS. Parts similar to those of the embodiment described with reference to FIG. 1 to FIG. In the embodiment shown in FIG. 7, a ring 22 that is fitted and fixed to the outer periphery of the root 25 of the bonding tool 24 is attached to the lower side of the shank 20 of the embodiment described with reference to FIGS. 1 to 6. . The lower end surface 23 of the ring 22 is mirror-finished so that light from the strobe 34 can be reflected. In the present embodiment, the ring 22 is a reflector, the end surface 23 is a reflecting surface, and the ring 22 is disposed adjacent to the root 25.

  As shown in FIG. 7B, in this embodiment, the camera 32 has a slightly blurred image 86 of the end surface 23 of the ring-shaped ring 22 with a high brightness (white) and a slightly curved surface of the bonding tool 24 slightly blurred. 26, a low brightness (black or gray) image 82 and a high brightness (white) backside image 84 of the semiconductor die 30 are obtained, and a circular outer shape of the image 86 of the end face 23 and the inclined curved surface 26 image 82 is obtained. A reference line 91, a square outline reference line 92 of the inclined curved surface 26 image 82 and the back surface image 84 of the semiconductor die 30 are extracted, and a relative position between the bonding tool 24 and the semiconductor die 30 is detected. The effect of this embodiment is the same as that of the embodiment described above with reference to FIGS.

  In another embodiment shown in FIG. 8A, the base 25 of the bonding tool 24 is stepped, and the lower surface 29 below the stepped portion 28 is mirror-finished so that light from the strobe 34 can be reflected. It is a thing. In the present embodiment, the step portion 28 of the bonding tool 24 is a reflector, the lower surface 29 of the step portion 28 is a reflecting surface, and the lower surface 29 is disposed adjacent to the root 25.

  As shown in FIG. 8B, in the present embodiment, the camera 32 has an image 88 of the lower surface 29 of the ring-shaped step portion 28 having a slightly blurred high brightness (white) and a slightly inclined tilt of the bonding tool 24. A low-lightness (black or gray) image 82 of the curved surface 26 and a high-lightness (white) image 84 of the back surface of the semiconductor die 30 are obtained. The outline reference line 91, the square outline reference line 92 of the inclined curved surface 26 image 82 and the back surface image 84 of the semiconductor die 30 are extracted, and the relative position between the bonding tool 24 and the semiconductor die 30 is detected. The effect of this embodiment is the same as that of the embodiment described above with reference to FIGS.

  10 die bonder, 11 guide rail, 12 X direction moving mechanism, 13 Y direction moving mechanism, 15 bonding head, 16 Z direction moving mechanism, 17 θ direction moving mechanism, 20 shank, 21, 23 end face, 22 ring, 24 bonding tool, 25 root, 26 inclined curved surface, 27 suction surface, 28 steps, 29 bottom surface, 30 semiconductor die, 32 camera, 33 field of view, 34 strobe, 35 reflector, 36 pickup stage, 37 bonding stage, 38 locus, 40 image processing unit 41, 51 CPU, 42, 52 Memory, 43 Image acquisition program, 44 Relative position detection program, 45, 55 Control data, 46, 56 Data bus interface, 47 Camera interface, 48 Strobe interface, 49, 59 data Tabas, 50 control unit, 53 position control program, 54 correction program, 57 moving mechanism interface, 60 communication line, 71-76 arrow, 81-89 image, 90 longitudinal center line, 91 circular outline reference line, 92 square outline Reference line, 93 Y-direction reference line, 94 X-direction reference line, 95 Y-direction measurement line, 96 X-direction measurement line, 97, 98 center, D focal depth, L1-L3 optical path length, ΔX, ΔY, Δθ deviation amount.

Claims (5)

A bonding tool having an adsorption surface for adsorbing a semiconductor die at the tip, a root thicker than the adsorption surface at the tip, and an inclined surface that connects the adsorption surface and the root and is inclined with respect to a longitudinal center line;
Have substantially parallel reflecting surface and the suction surface, and a gripping portion for gripping the root source,
A light source disposed below the suction surface and projecting on the suction surface;
A black circular image of the inclined surface, a white ring-shaped image of the reflecting surface adjacent to the outer periphery of the circular image of the inclined surface, and a circular image of the inclined surface, which are disposed below the suction surface. A camera that captures a white image of the lower surface of the semiconductor die located in the same field of view;
Located in the black circular image of the inclined surface captured by the camera, the white ring-shaped image of the reflecting surface adjacent to the outer periphery of the circular image of the inclined surface, and the circular image of the inclined surface An image processing unit that performs image processing on a captured image including a white image on a lower surface of the semiconductor die , and
Wherein the image processing unit, with respect to the captured image which the camera is captured, contour setting means for setting a second contour reference lines corresponding to the first outer reference line and the edge of the semiconductor die against the outer periphery of the inclined surface Having a die bonder. The die bonder according to claim 1,
The image processing unit
A first center coordinate in the first outer shape reference line and a second center coordinate in the second outer shape reference line are calculated, and the bonding tool with respect to the bonding tool is calculated based on a difference between the first and second center coordinates. A die bonder comprising: a deviation amount detecting means for detecting a deviation amount of the semiconductor die. The die bonder according to claim 1,
The image processing unit
Rotation amount detection means for calculating an angle difference between the first outline reference line and the second outline reference line, and detecting a deviation amount of the semiconductor die in the rotation direction with respect to the bonding tool based on the angle difference. A die bonder comprising: The die bonder according to any one of claims 1 to 3,
The camera is a die bonder having a depth of focus that focuses on the lower surface of the semiconductor die rather than the inclined surface and the reflecting surface. The die bonder according to any one of claims 1 to 4,
The contour setting means bonder for setting said second contour reference lines corresponding to the edge of the first outer reference line and the semiconductor die against the outer periphery of the inclined surface with a predetermined binarization threshold.