Wire bonding device

Abstract

A wire bonding apparatus capable of suppressing a decrease in jointability is provided. The wire bonding apparatus includes a joint platform on which a semiconductor chip is placed; a wire bonding unit having a capillary that bonds a wire to the semiconductor chip, a Z-axis drive section that reciprocally moves the capillary, and an XY stage for tools that moves the capillary and the Z-axis drive section along a two-dimensional plane that intersects with a direction of the reciprocating movement; and a base having an optical system and an XY stage for the optical system that moves the optical system along a two-dimensional plane that intersects with the direction of the reciprocating movement, and on which the wire bonding unit is mounted. The wire bonding unit is mounted to a first portion of the base, and the XY stage for the optical system is mounted to a second portion of the base that is different from the first portion.

Description

Technical Field

[0001] This invention relates to a wire bonding device. Background Technology

[0002] Patent documents 1 and 2 disclose a wire bonding apparatus. The wire bonding apparatus bonds bonding wires to a desired location on a substrate or semiconductor chip via a capillary. To ensure the capillary moves correctly to the bonding position, position control is performed, for example, based on image processing.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 08-306732

[0006] Patent Document 2: Japanese Patent Application Publication No. 10-242191 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In the field of wire bonding, it is desirable to reliably bond the bonding wire to an object. The characteristics of the bonded portion, known as bondability, are affected by several key factors during the bonding process. For example, if unexpected vibrations are applied to the capillary from the outside during the bonding process, causing it to vibrate unintentionally, the bondability will decrease.

[0009] The purpose of this invention is to provide a wire bonding device that can suppress the decline in bonding strength.

[0010] Technical means to solve the problem

[0011] An embodiment of the wire bonding apparatus of the present invention includes: a bonding platform on which a bonding object is placed; a wire bonding unit having a capillary tube for bonding a wire to the bonding object, a capillary drive unit for reciprocating the capillary tube, and an XY platform for moving the capillary tube and the capillary drive unit along a two-dimensional plane intersecting the direction of reciprocating movement; a camera unit for capturing an image of the bonding object placed on the bonding platform; and a base on which the wire bonding unit and the camera unit are mounted. The wire bonding unit is mounted on a first portion of the base. The camera unit is mounted on a second portion of the base, different from the first portion.

[0012] In the wire bonding apparatus, the wire bonding unit and the camera unit are mounted on different parts of the base. This allows vibrations generated by the camera unit's operation to be sufficiently attenuated before reaching the wire bonding unit. Consequently, vibrations generated by the camera unit's operation are less likely to affect the operation of the wire bonding unit. Therefore, bonding can be performed in a good condition, thus suppressing any decrease in bonding quality.

[0013] In one embodiment, the camera unit can photograph a reference point representing the position of the wire bonding unit and the bonding object placed on the bonding platform. According to this structure, the camera unit can preferably be calibrated relative to the wire bonding unit.

[0014] In one embodiment, the camera unit can acquire a first image including a reference point and a second image including the bonding object and different from the first image. This structure also preferably allows for calibration of the camera unit relative to the wire bonding unit.

[0015] One embodiment of the wire bonding apparatus may further include a control unit that obtains a calibration value that calculates the correlation between the field-of-view coordinates of a reference point in the first image and the position coordinates of the XY platform. With this structure, calibration of the camera unit relative to the wire bonding unit can also preferably be performed.

[0016] In one embodiment, the reference point may be located on the upper surface of the ultrasonic horn of the wire bonding unit. This structure also preferably allows for the calibration of the camera unit relative to the wire bonding unit.

[0017] In one embodiment, the imaging unit may include an imaging device and an optical system that guides light from the bonding object and a reference point to the imaging device. The optical system may include a lens and a light branch disposed on the optical axis between the imaging device and the bonding object, and between the imaging device and the reference point. The lens may be disposed on the imaging device side. The light branch may be disposed on the bonding object side and the reference point side. According to this structure, calibration of the imaging unit relative to the wire bonding unit can be easily performed.

[0018] In one embodiment, the optical branch may include a semi-transparent mirror and illumination that shines light onto the semi-transparent mirror. The optical branch uses the light shining onto the semi-transparent mirror to switch between the optical path for acquiring a first image and the optical path for acquiring a second image. With this structure, the calibration of the camera unit relative to the wire bonding unit can also be performed easily.

[0019] The effects of the invention

[0020] According to the present invention, a wire bonding device that can suppress the decline in bonding strength can be provided. Attached Figure Description

[0021] Figure 1 This is a diagram showing the wire bonding device as viewed from the front.

[0022] Figure 2 This is a side view of the wire bonding device of the embodiment.

[0023] Figure 3 This is a picture showing the camera unit from the front.

[0024] Figure 4 This is a view of the camera unit from the side.

[0025] Figure 5 (a) is a diagram representing the first optical path. Figure 5 (b) is a diagram representing the second optical path.

[0026] Figure 6 (a) is a diagram representing the third optical path. Figure 6 (b) is a diagram representing the fourth optical path.

[0027] Figure 7 This is a diagram of the third optical path of the camera unit viewed from an angle.

[0028] Figure 8 This is the functional block diagram of the controller.

[0029] Figure 9 This is a flowchart illustrating the main steps of the wire bonding method.

[0030] Figure 10 This is a process table that details the steps for setting the camera offset value.

[0031] Figure 11 of (a), Figure 11 (b) Figure 11 (c) and Figure 11 (d) is an example of an image obtained during the process of setting the camera offset value.

[0032] Figure 12 (a) and Figure 12 (b) is a process table that shows in detail the processes for performing the positioning action.

[0033] Figure 13 This is an example of an image used to illustrate a process of performing a positioning action.

[0034] Figure 14 This is a diagram showing a modified example of the camera unit viewed from the side.

[0035] Figure 15 This is a diagram showing a detailed side view of a modified example of the camera unit.

[0036] Figure 16 This is another example of a modified view of the camera unit from the side.

[0037] Figure 17 This is a side view of a modified example of a wire bonding device, representing a reference point.

[0038] Figure 18 This is a process table that details a variation of the process for setting the camera offset value.

[0039] Explanation of symbols

[0040] 1: Capillary

[0041] 2: Ultrasonic welding head

[0042] 5: Z-axis drive unit (capillary drive unit)

[0043] 6: Tools using the XY platform (XY platform)

[0044] 7: Joining Platform

[0045] 10, 10B: Optical System

[0046] 11: XY platform for optical systems (camera drive unit)

[0047] 21: Reference Point

[0048] 21A, 21B, 21C: Reference points

[0049] 30B, 31B, 37: Semi-transparent mirrors

[0050] 30E, 30F: Lenses

[0051] 34, 38: Semi-transparent mirrors (light branch points)

[0052] 40: Wire bonding unit

[0053] 50, 50A: Camera Unit (Camera Section)

[0054] 70: Base

[0055] 71a: Part One

[0056] 71b: Part Two

[0057] 100: Wire bonding device

[0058] 200: Joint line Detailed Implementation

[0059] Hereinafter, the embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. The same symbols are used to denote the same components in the illustrations, and repeated descriptions are omitted.

[0060] Figure 1 This is a front view of the wire bonding device 100 according to an embodiment of the present invention. Figure 2 yes Figure 1 The wire bonding apparatus 100 is shown as a side view. The wire bonding apparatus 100 bonds bonding wires 200 to a semiconductor chip 20.

[0061] The wire bonding device 100 includes a wire bonding unit 40, a camera unit 50, and a controller 60 (control unit: see reference). Figure 2 The main components include the bonding unit 40 and the base 70. The wire bonding unit 40 bonds the bonding wire 200 to the semiconductor chip 20. The imaging unit 50 acquires images for controlling the operation of the wire bonding unit 40. The controller 60 controls the operation of the wire bonding unit 40 and the imaging unit 50. For example, the controller 60 controls the imaging unit 50. As a result, images including the semiconductor chip 20 and the capillary 1 can be obtained.

[0062] The controller 60 controls the wire bonding unit 40 by processing images. The control of the wire bonding unit 40 includes a series of actions such as position control of the capillary 1 tip relative to the semiconductor chip 20 and control of the wire bonding action based on the capillary 1. At least the wire bonding unit 40 and the camera unit 50 are mounted on the base 70. The base 70 maintains the relative position of the camera unit 50 with respect to the wire bonding unit 40. The controller 60 may be mounted on the base 70. Alternatively, the controller 60 may not be mounted on the base 70.

[0063] <Wire bonding unit>

[0064] The wire bonding unit 40 includes a capillary tube 1, an ultrasonic welding head 2, a wire clamp 3, a welding head support 4, a Z-axis drive unit 5 (capillary drive unit), and an XY platform 6 for tools (XY platform).

[0065] The capillary tube 1, acting as a bonding tool, bonds the bonding wire 200 to the semiconductor chip 20. The capillary tube 1 is detachably mounted on the front end of the ultrasonic welding head 2. The base end of the ultrasonic welding head 2 is mounted on the front end of the welding head support 4. In addition to the ultrasonic welding head 2, the base end of the wire clamp 3 is also mounted on the front end of the welding head support 4. The front end of the wire clamp 3 is approximately located above the capillary tube 1.

[0066] The base end of the welding head support 4 is mounted on the Z-axis drive unit 5. The Z-axis drive unit 5, acting as a joint, moves the welding head support 4 along an arc-shaped trajectory. Based on the movement of the welding head support 4 along the arc-shaped trajectory, the capillary tube 1, ultrasonic welding head 2, and wire clamp 3, directly or indirectly mounted on the welding head support 4, also move along the arc-shaped trajectory. Through the movement of the capillary tube 1 along the arc-shaped trajectory, the capillary tube 1 performs a joining action. A welding torch arm 91 is also mounted on the Z-axis drive unit 5. An adapter 92 for the welding torch (not shown) is mounted on the front end of the welding torch arm 91. The Z-axis drive unit 5 is mounted on the tool XY platform 6. The capillary tube 1, ultrasonic welding head 2, wire clamp 3, welding head support 4, and Z-axis drive unit 5, directly or indirectly mounted on the Z-axis drive unit 5, can move parallel to each other along the XY plane. The tool XY platform 6 is a high-speed, high-precision platform using a servo motor. The bonding platform 7 is positioned below the capillary 1. The bonding platform 7 holds the semiconductor chip 20 below the capillary 1.

[0067] In summary, in the wire bonding unit 40, the capillary 1, which serves as a bonding tool, is mounted on the ultrasonic welding head 2, and the Z-axis drive unit 5, which performs the bonding action by moving the capillary 1 along an arc-shaped trajectory, is mounted on the tool XY platform 6.

[0068] <Camera Unit>

[0069] The camera unit 50 acquires an image for positioning the capillary 1. The camera unit 50, which is a positioning optical system, includes a different optical system XY platform 11 independent of the tool XY platform 6.

[0070] The imaging unit 50 includes an optical system 10 (imaging unit) and an XY platform 11 for the optical system (camera drive unit). The optical system 10 acquires images with different imaging ranges. For example, the optical system 10 acquires an image containing a mark indicating the position of a semiconductor chip 20, and an image containing a reference point 21 (described later) indicating the position of a capillary 1. The optical system 10 acquires images with different magnifications. The XY platform 11 moves the optical system 10 relative to the object being imaged. The object being imaged is an ultrasonic welding head 2, etc., on which the semiconductor chip 20 and the reference point 21 are provided.

[0071] Figure 3 This is a diagram showing the optical system 10 viewed from the front. Figure 4 This is a diagram showing the optical system 10 viewed from the side. (As shown...) Figure 3 and Figure 4As shown, the optical system 10 includes a first camera device 30A, a second camera device 31A, a reflector 36, a semi-transparent reflector 30B, a semi-transparent reflector 31B, a semi-transparent reflector 34, a semi-transparent reflector 37, a semi-transparent reflector 38, a first illumination 32, a second illumination 33, a first optical component 30, a second optical component 31, and a third optical component 39.

[0072] The first camera device 30A acquires high-magnification images. The second camera device 31A acquires low-magnification images. The first camera device 30A and the second camera device 31A can be, for example, high-resolution cameras. For example, if a 1.1-inch high-resolution camera with 12 megapixels is used as the first camera device 30A and the second camera device 31A, and the magnification is set to 2x, the field of view is 4.2mm × 3.5mm. This field of view is approximately twice the low-magnification field of view of the binoculars in a conventional wire bonder. In this case, the pixel resolution is 1.7μm / pixel. Based on image processing, a recognition accuracy of a fraction to a tenth of the pixel decomposition can be achieved. For example, when the required bonding accuracy is 2μm, sufficient recognition accuracy can be ensured as a high-precision wire bonder. With both low-magnification and high-magnification binoculars, the number of camera shots can be reduced during wire positioning, as described later. Furthermore, when using a high-resolution camera and ensuring a wide field of view, the optical system 10 can also be monocular.

[0073] The optical system 10 acquires images of objects present in the first field of view 202 and images of objects present in the second field of view 203. Therefore, the optical system 10 constitutes a first optical path R1 (refer to...). Figure 5 (a) and the second optical path R2 (refer to) Figure 5 (b)). The first optical path R1 guides the light from the first field of view 202 to the first imaging device 30A. The second optical path R2 guides the light from the first field of view 202 to the second imaging device 31A. Furthermore, the optical system 10 constitutes a third optical path R3 (see reference). Figure 6 (a) and the fourth optical path R4 (refer to) Figure 6 (b)). The third optical path R3 guides the light from the second field of view 203 to the first camera device 30A. The fourth optical path R4 guides the light from the second field of view 203 to the second camera device 31A.

[0074] The positions of the first field of view 202 and the second field of view 203 are different. The optical path length from the first optical element 30 to the semiconductor chip 20, which is the object of imaging, is the same as the optical path length from the second optical element 31 to the reference point 21, which is the object of imaging. Specifically, the optical path length can be expressed as a1 + a2 = b1 + b2. a1 is the optical path length from the semiconductor chip 20 to the semi-transparent mirror 34. a2 is the optical path length from the semi-transparent mirror 34 to the semi-transparent mirror 37. b1 is the optical path length from the reference point 21 to the mirror 36. b2 is the optical path length from the mirror 36 to the semi-transparent mirror 37. The magnification related to the calibration value described later is the same in both the first field of view 202 and the second field of view 203.

[0075] like Figure 5 As shown in (a), the first optical path R1 guides light from the first field of view 202 to the first imaging device 30A. The first field of view 202 is equipped with a semiconductor chip 20. Therefore, the first optical path R1 guides light from the semiconductor chip 20 to the first imaging device 30A. The first optical path R1 includes a semi-transparent mirror 34 (light branch) and a first optical component 30.

[0076] like Figure 5 As shown in (b), the second optical path R2 guides light from the first field of view 202 to the second imaging device 31A. Therefore, the second optical path R2 guides light from the semiconductor chip 20 to the second imaging device 31A. The second optical path R2 includes a semi-transparent mirror 34, a semi-transparent mirror 37, a semi-transparent mirror 30B, a semi-transparent mirror 31B, and a second optical component 31.

[0077] In summary, the light from the semiconductor chip 20, after passing through the semi-transparent mirrors 34 and 37, is divided by the semi-transparent mirror 30B into two paths: one guided to the high-magnification side of the first optical component 30, and the other guided to the low-magnification side of the second optical component 31. The light guided to the high-magnification side of the first optical component 30 is captured by the high-magnification first imaging device 30A. The light guided to the low-magnification side of the second optical component 31 is captured by the low-magnification second imaging device 31A. The field of view through which the semiconductor chip 20 is imaged via these optical paths is referred to as the first field of view 202.

[0078] like Figure 6 (a) and Figure 7 As shown, the third optical path R3 guides light from the second field of view 203 to the first imaging device 30A. A reference point 21, which is disposed on the ultrasonic welding head 2, is located in the second field of view 203. Therefore, the third optical path R3 guides light from the reference point 21 to the first imaging device 30A. The third optical path R3 includes a reflector 36, a semi-transparent reflector 37, and a first optical component 30.

[0079] The second field of view 203 captures an image of a reference point 21 located at any point on the tool XY platform 6. The reference point 21 is a mark formed on the upper surface of the ultrasonic welding head 2. The reference point 21 is set on a part that can be moved by the tool XY platform 6.

[0080] Reference point 21 is provided, for example, on the ultrasonic welding head 2. Ideally, reference point 21 is provided at a position close to the capillary tube 1. A wire clamp 3 is provided on the ultrasonic welding head 2. However, the upper surface of the ultrasonic welding head 2 can be observed through the gap in the wire clamp 3. An identification mark (e.g., a cross shape) that is easy to recognize and meets the desired accuracy can also be attached to the upper surface of the ultrasonic welding head 2. The identification mark is reference point 21. For example, the edge of the ultrasonic welding head 2 can be used instead of the actively provided identification mark as reference point 21. Alternatively, a pattern of the surface of the metal component constituting the ultrasonic welding head 2 can be used as reference point 21.

[0081] The mating area is limited by the position of the reference point 21. For example, when the required accuracy of positional alignment is less stringent, the degree of freedom in setting the position of the reference point 21 can be increased. The reference point 21 can be placed at a point far from the capillary 1. The degree of freedom in arranging the parts for making the optical path lengths constituting the first field of view 202 and the second field of view 203 consistent is increased. Variations of the reference point 21 will be described later.

[0082] like Figure 6 As shown in (b), the fourth optical path R4 guides light from the second field of view 203 to the second imaging device 31A. Therefore, the fourth optical path R4 guides light from the reference point 21 to the second imaging device 31A. The fourth optical path R4 includes a reflector 36, a semi-transparent reflector 37, a semi-transparent reflector 30B, a semi-transparent reflector 31B, and a second optical component 31.

[0083] The light illuminating the reference point 21 from the second illumination 33 passes through the reflector 36 and the semi-transparent reflector 37, and is then divided by the semi-transparent reflector 30B into a light path that is guided to the first optical component 30 on the high magnification side and a light path that is guided to the second optical component 31 on the low magnification side.

[0084] The light guided to the high-magnification side by the first optical component 30 is captured by the high-magnification first imaging device 30A. The light guided to the low-magnification side by the second optical component 31 is captured by the low-magnification second imaging device 31A.

[0085] The first optical component 30 and the second optical component 31, which are lenses, are driven in the optical axis direction to perform focusing adjustment (focus adjustment).

[0086] The optical system 10 can switch between forming a first field of view configuration that constitutes the first optical path R1 and the second optical path R2, and a second field of view configuration that constitutes the third optical path R3 and the fourth optical path R4. In other words, the optical system 10 can switch between forming a first field of view configuration that guides light from the first field of view 202 to the first camera device 30A and the second camera device 31A, and a second field of view configuration that guides light from the second field of view 203 to the first camera device 30A and the second camera device 31A, respectively.

[0087] The switching of modes can be controlled by switching the first illumination 32 on and off and the second illumination 33 on and off. The first illumination 32 is disposed on the back side of the semi-transparent mirror 34 via the third optical component 39. The first illumination 32 is disposed on the extension line of the optical axis from the semi-transparent mirror 34 to the first field of view 202. The first illumination 32 illuminates the semiconductor chip 20, which is the object to be bonded, through the third optical component 39 and the semi-transparent mirror 34. The second illumination 33 is disposed on the back side of the semi-transparent mirror 38 (light branch) that intersects the optical axis from the semi-transparent mirror 37 to the second field of view 203. The second illumination 33 illuminates the reference point 21 through the semi-transparent mirror 38.

[0088] When the first field of view is set, the first illumination 32 is turned on and the second illumination 33 is turned off (see reference). Figure 5 (a) and Figure 5 (b)). In the second field of view configuration, the first illumination 32 is turned off and the second illumination 33 is turned on (see reference). Figure 6 (a) and Figure 6 (b)). The lighting and extinguishing of the first lighting 32 and the second lighting 33 can be controlled by control signals provided from the controller 60.

[0089] like Figure 4 As shown, the components constituting the optical system 10 are fixed to a frame (not shown). This maintains the relative positional relationship between the components constituting the optical system 10. Furthermore, the frame on which the components are mounted is mounted on the XY platform 11 for the optical system. The XY platform 11 for the optical system is mounted on the base 70. For example, the XY platform 11 for the optical system is a suspension structure suspended from the wire bonding unit 40. Positional accuracy of the XY platform 11 for the optical system is not required. For example, the positional accuracy of the XY platform 11 for the optical system can be lower than that of the XY platform 6 for tools.

[0090] The first field of view 202 and the second field of view 203 are offset in the X direction. That is, the first field of view 202 is offset relative to the second field of view 203. The reason for the offset is to avoid interference with the bonding line 200 extending from the bonding line supply section (not shown) located on the upper surface of the tool (ultrasonic welding head 2) disposed in the second field of view 203. Depending on the structure of the supply line system, the upper surface of the tool may also be used as the second field of view 203 without the aforementioned offset. The structure of the optical system corresponding to this case will be described in detail later as a variation.

[0091] The first field of view 202 and the second field of view 203 pass through several optical components until the light paths converge in the semi-transparent mirror 37. If these optical components deform or shift due to temperature changes, positioning errors will occur. Several countermeasures can be listed to address positioning errors. The first countermeasure is temperature correction for image deviation. The second countermeasure is to use optical components made of materials with low coefficients of linear expansion. The third countermeasure is to use an optical system structure that minimizes image deviation even with temperature changes. In other words, it is to use an optical system structure that eliminates image deviation even with temperature changes. Furthermore, countermeasures different from the first to third countermeasures can also be used.

[0092] In the imaging unit 50 of this embodiment, the distance from the heater that heats the semiconductor chip 20 to the imaging unit 50 is greater than the distance from the heater to the imaging unit in a conventional wire bonding apparatus. For example, the distance from the heater that heats the semiconductor chip 20 to the imaging unit 50 is approximately three times the distance from the heater to the imaging unit in a conventional wire bonding apparatus. Therefore, the effects of temperature changes caused by heating of the imaging unit 50 due to the heat generated by the heater can be suppressed.

[0093] <Base>

[0094] The base 70 only needs to maintain the position of the camera unit 50 relative to the wire bonding unit 40. Therefore, the specific structure of the base 70 can be appropriately modified according to the structure of the wire bonding unit 40, the structure of the camera unit 50, and the position of the camera unit 50 relative to the wire bonding unit 40. An example of the structure of the base 70 will be described below.

[0095] like Figure 1 and Figure 2As shown, the base 70 has a main frame 71 and a sub-frame 72. The main frame 71 is a structure with high rigidity. When the wire bonding unit 40 and the camera unit 50 are installed, the main frame 71 will not deform significantly relative to the forces generated by their weight or movement. For example, when the capillary 1 is reciprocated along an arc-shaped trajectory by the Z-axis drive unit 5, an excitation force is generated. The main frame 71 will not deform significantly due to the excitation force, affecting the accuracy and quality of the bonding. The sub-frame 72 is the mechanical interface for fixing the units and parts constituting the wire bonding device 100 to the main frame 71. Like the main frame 71, the sub-frame 72 will not deform significantly due to the weight of the mounted object or external forces.

[0096] Figure 2 In this example, the subframe 72 is fixed to the first portion 71a of the main frame 71. A wire bonding unit 40 is fixed to the subframe 72. More specifically, a tooling XY platform 6 and a bonding platform 7 are fixed to the subframe 72. The wire bonding unit 40 is fixed to the main frame 71 via the subframe 72. This structure is illustrative. For example, the wire bonding unit 40 may also be directly fixed to the main frame 71. On the other hand, the camera unit 50 is directly fixed to the second portion 71b of the main frame 71.

[0097] The wire bonding unit 40 and the camera unit 50 are fixed side-by-side to a common base 70. In other words, the camera unit 50 is not directly disposed on the wire bonding unit 40. For example, in the wire bonding apparatus 100 of the embodiment, the camera unit 50 is not mounted on the tool XY platform 6 of the wire bonding unit 40. A structure exists between the wire bonding unit 40 and the camera unit 50. For example, a main frame 71 and a sub-frame 72 exist between the wire bonding unit 40 and the camera unit 50.

[0098] <Controller>

[0099] like Figure 8 As shown, the controller 60 has several functional components. The controller 60 is a computer and electronic circuits connected to the computer, and its functional components are implemented by a central processing unit (CPU) executing a prescribed program. The controller 60 has a first platform control unit 61, a bonding control unit 62, a second platform control unit 63, a camera control unit 64, a lighting control unit 65, a computing processing unit 66, and a storage unit 67 as functional components. In addition to these functional components, the controller 60 may also have functional components for the operations required by the wire bonding device 100.

[0100] The first platform control unit 61 outputs control signals to the tool XY platform 6. The bonding control unit 62 outputs control signals to the Z-axis drive unit 5. The second platform control unit 63 outputs control signals to the optical system XY platform 11. The camera control unit 64 outputs control signals to the first camera device 30A and the second camera device 31A. The camera control unit 64 receives image data from the first camera device 30A and the second camera device 31A. The lighting control unit 65 outputs control signals to the first lighting 32 and the second lighting 33. The calculation processing unit 66 performs prescribed calculation processing using the image data, etc. The calculation processing unit 66 outputs coordinate information, etc., for generating control signals to the first platform control unit 61 and the second platform control unit 63. The storage unit 67 stores various information required for the operation of the wire bonding device 100.

[0101] <Wire bonding method>

[0102] The following is for reference Figure 9 The wire bonding method using the wire bonding apparatus 100 will be described. The wire bonding method includes a setting step of the apparatus and an actual bonding step. Specifically, the wire bonding method includes a setting step 1 (S10), a setting step 2 (S20), and a bonding step (S30).

[0103] Setting process 1 (S10) is a process not caused by the equipment. Setting process 1 (S10) includes: a process S1 of performing a first calibration, a process S2 of performing a second calibration, and a process S3 of setting the camera offset value.

[0104] Setting up step 2 (S20) is a process initiated by the equipment. Setting up step 2 (S20) is performed each time the mating object is changed. Setting up step 2 (S20) includes: step S4 of registering the first alignment point, step S5 of registering the second alignment point, and step S6 of performing pad centering.

[0105] The bonding process (S30) includes the lead wire positioning process S7 and the positioning action process S8.

[0106] <The procedure for performing the first calibration>

[0107] The first calibration is the operation of obtaining the correlation between the encoder values ​​of the tool XY platform 6 and the coordinates of pixels in the second field of view 203 of the camera unit 50. This correlation refers to the relationship between the scale and coordinate rotation of the XY coordinate system of the tool XY platform 6 and the XY coordinate system within the second field of view 203 of the camera. The operation of obtaining this correlation is called camera calibration. The origin of the XY coordinate system of the tool XY platform 6 is set at any position readable by the encoder. The origin of the XY coordinate system of the camera is set at any position within the field of view. Hereinafter, for ease of explanation, the origin of the camera's XY coordinate system will be set as the center of the field of view. The coordinates of pixels in the second field of view 203 are an example of field of view coordinates. The encoder values ​​are an example of position coordinates.

[0108] As part of the first calibration step S1, camera calibration is performed. In step S1, camera calibration values ​​are obtained using information about the relationship between the XY platform 6 and the imaging unit 50 as a calibration tool. The camera calibration values ​​are set for the first imaging device 30A on the low magnification side and also for the second imaging device 31A on the high magnification side.

[0109] In process S1, firstly, (1) the reference point 21 is contained in the second field of view 203 by moving the tool XY platform 6. Secondly, a low-magnification image containing the reference point 21 and a high-magnification image containing the reference point 21 are obtained. Secondly, (2) a characteristic pattern is registered from the obtained image. Secondly, (3) the action of moving the tool XY platform 6 at a predetermined interval and the action of obtaining the image of the reference point 21 after the movement are repeated. In addition, the amount of movement of the tool XY platform 6 is obtained using an encoder during each movement. Secondly, (4) the amount of movement and direction of movement of the pattern are calculated by using image recognition processing of the image obtained during each movement. Secondly, (5) the relationship (size, direction) between the encoder of the tool XY platform 6 and the pixels of the first camera device 30A and the second camera device 31A is calculated by statistical processing of the amount of movement and direction of movement of the pattern. The relationship is a first calibration value.

[0110] <The procedure for performing the second calibration>

[0111] The second calibration is the operation of obtaining the correlation between the encoder value or pulse value of the XY platform 11 of the optical system and the pixels in the first field of view 202 of the imaging unit 50. This correlation is the scale and coordinate rotation correlation between the XY coordinate system of the XY platform 11 of the optical system and the XY coordinate system within the second field of view 203 of the camera. The operation of obtaining this correlation is also called camera calibration. As a step S2 for performing the second calibration, camera calibration is performed. In step S2, camera calibration values ​​are obtained as information to correct the relationship between the XY platform 11 of the optical system and the imaging unit 50. The camera calibration values ​​are set on the low-magnification side of the first imaging device 30A and also on the high-magnification side of the second imaging device 31A.

[0112] In process S2, (1) the semiconductor chip 20 is housed in the first field of view 202 by moving the optical system using the XY platform 11. Next, a low-magnification image containing the semiconductor chip 20 and a high-magnification image containing the semiconductor chip 20 are obtained. Next, (2) a characteristic pattern is registered from the obtained image. Next, (3) the action of moving the optical system using the XY platform 11 at a predetermined interval and the action of obtaining an image of the semiconductor chip 20 after the movement are repeated. In addition, the amount of movement of the optical system using the XY platform 11 is obtained from the encoder each time it is moved. In addition, the amount of movement of the optical system using the XY platform 11 can also be obtained using the pulse value of the optical system using the XY platform 11. Next, (4) the amount of movement and the direction of movement of the pattern are calculated by using image recognition processing of the image obtained each time it is moved. Next, (5) the relationship (size, direction) between the position (encoder or pulse position) of the optical system using the XY platform 11 and the pixels of the first camera device 30A and the second camera device 31A is calculated by statistical processing of the amount of movement and the direction of movement of the pattern. The relationship is the second calibration value.

[0113] <The process of setting camera offset values>

[0114] The camera offset value refers to the distance the XY platform 6 needs to move in order to align with the center of the first field of view 202 when the reference point 21 on the XY platform 6 is located at the center of the second field of view 203. The camera offset value in this embodiment is a different concept from the camera offset terminology used in conventional wire bonding machines. Figure 10 This is a process table detailing the process S3 for setting the camera offset value. In process S3, the relationship between the optical system 10 and the joining tool is set. The relationship between the optical system 10 and the joining tool is also called the camera offset value. The process S3 for setting the camera offset value includes: a first action S31 for setting the joining point, a second action S32 for joining or forming an indentation, and a third action S33 for calculating the joining position.

[0115] The first action S31 includes the following actions: The optical system is operated using the XY platform 11, with the semiconductor chip 20 housed in the first field of view 202 (S31a, S31b, see reference). Figure 11 (a)). Next, the center 202C of the first field of view 202 is set as the junction point (S31c). Next, the tool is run on the XY platform 6 with the reference point 21 housed in the second field of view 203 (S31d). Next, the second field of view 203 is photographed (S32e, reference). Figure 11 (b)). Next, calculations are performed (S31f). Specifically, the tool read from the encoder is set to (x0, y0) using XY platform coordinates. Next, the position (x0s', y0s') of the reference point 21 in the camera coordinates of the second field of view 203 is determined by image recognition (S31e, reference). Figure 11 (b)). Next, based on the first calibration value obtained earlier, the coordinates are transformed from camera coordinates in pixel units to actual lengths (μm). As a result, coordinates (x0s, y0s) are obtained. The XY coordinates and orientation of the tool XY platform 6 are the same as the scale. The origin is the same as the camera coordinates of the second field of view 203. Therefore, when the tool XY platform 6 is moved (-x0s, -y0s), the reference point 21 becomes the center of the second field of view 203. In practical applications, it is not necessary to move the reference point 21 to the center of the field of view. After the first action S31, the optical system XY platform 11 retracts (S31g).

[0116] The second action S32 includes the following actions: The tool is moved along the XY platform 6 by a distance according to the camera offset value stored in the device, moving the capillary 1 to the engagement point (S32a). Next, the Z-axis drive unit 5 engages (S32b). Alternatively, an indentation-forming action can be performed instead of the engagement action. After the second action S32, the optical system retracts using the XY platform 11 (S32c).

[0117] The third action S33 includes the following actions. The optical system XY platform 11 is operated (S33a) in such a way that the junction point 22 is housed within the first field of view 202. The position of the optical system XY platform 11 in S33a is the same as the position of the optical system XY platform 11 in S31a and S31c. In other words, the output value of the encoder set on the optical system XY platform 11 or the pulse provided to the optical system XY platform 11 is the same value. Next, imaging of the first field of view 202 is performed (S33b, see reference). Figure 11(c) Next, calculation is performed (S33c). In the calculation, the joining position relative to the center of the first field of view 202 is obtained. First, the coordinates (Xb', Yb') of the joining point 22 are obtained based on the camera coordinates of the first field of view 202. Next, the coordinates (Xb', Yb') are transformed into the coordinates of the tool XY platform 6. As a result, the coordinates (Xb, Yb) are obtained. Next, the tool XY platform 6 is operated in such a way that the reference point 21 is included in the second field of view 203 (S33d). Next, the second field of view 203 is photographed (S33e, reference point 21 is included in the second field of view 203). Figure 11 (d) Then, calculation (S33f) is performed. Specifically, the tool's XY platform coordinates read from the encoder are set to (x1, y1). The position (x1s', y1s') of the reference point 21 in the camera coordinates of the second field of view 203 is determined by image recognition. The position of the reference point 21 is converted to the coordinate scale of the tool's XY platform 6. As a result, the coordinates (x1s, y1s) are obtained.

[0118] The wire bonding device 100 stores camera offset values ​​(Xc0, Yc0). The camera offset values ​​change due to temperature variations, etc. The change in camera offset values ​​(ΔXc, ΔYc) is as shown in equation (1) below if the calculated values ​​are used.

[0119] (ΔXc, ΔYc)=((x1s-x1)-(x0s-x0)+Xb, (y1s-y1)-(y0s-y0)+Yb)···(1)

[0120] Therefore, the newly set camera offset values ​​(Xc, Yc) are as shown in equation (2) below.

[0121] (Xc, Yc)=(Xc0+ΔXc, Yc0+ΔYc)=(Xc0+(x1s-x1)-(x0s-x0)+Xb, Yc0+(y1s-y1)-(y0s-y0)+Yb)···(2)

[0122] <The process of registering the first alignment point>

[0123] Alignment points are registered according to the type of each part to be bonded (step S4). In step S4, alignment points on the chip side are set. Specifically, firstly (1) the semiconductor chip 20 to be bonded is moved to the first field of view 202 by running the optical system on the XY platform 11. Secondly (2) with the semiconductor chip 20 housed in the first field of view 202, an image is obtained by the first imaging device 30A and also by the second imaging device 31A. Next, (3) based on the obtained images, the characteristic areas of the semiconductor chip 20 are registered as the first alignment points.

[0124] <The procedure for registering the second alignment point>

[0125] Alignment points are registered according to the type of part to be joined (step S5). In step S5, alignment points on the lead side are set. Specifically, (1) the lead of the semiconductor chip 20 to be joined is moved in a manner that includes the first field of view 202 by running the optical system with the XY platform 11. Furthermore, in the case of a second alignment point including the lead side, it is not necessary to run the optical system with the XY platform 11 inside the field of view where the first alignment point of the semiconductor chip 20 is registered. In this case, the image obtained in step S4 of registering the first alignment point can be used. Next, (2) an image is obtained by the first imaging device 30A and also by the second imaging device 31A while the lead side of the semiconductor chip 20 is contained in the first field of view 202. Next, (3) based on the obtained image, the characteristic area of ​​the lead side of the semiconductor chip 20 is registered as a second alignment point.

[0126] <The process of centering the padding>

[0127] Imaging is performed with each pad housed in the first field of view 202 (step S6). The images overlap in a certain area at the end of the field of view. As a result, the overall position of the pads can be determined through multiple images. Furthermore, if the XY platform 11 of the optical system has good accuracy, it is not necessary to overlap the ends of the images.

[0128] <The process of positioning the lead>

[0129] Perform the lead positioning process S7 (refer to...) Figure 12 (a)). With each lead 204 (refer to) Figure 13 The tool is operated using the XY platform 6 in a manner where it is housed within the first field of view 202 (S7a). Next, an image of the first field of view 202 is acquired (S7b). The image includes each lead wire 204. An image is captured with each lead wire 204 housed within the first field of view 202. The images overlap in a certain area at the ends of the field of view. As a result, the overall position of the lead wires 204 can be determined through multiple images. Furthermore, if the XY platform 11 of the optical system has good accuracy, it is not necessary to overlap the ends of the images.

[0130] <Procedure for performing positioning actions>

[0131] pass Figure 12 The positioning is performed by a series of actions shown in the process table of (b) (process S8). The positioning action S8 includes: the fourth action S81 for alignment, the fifth action S82 for obtaining correlation, the sixth action S83 for alignment, and the seventh action S84 for obtaining correlation. Figure 13This is an example of an image of the first field of view 202 obtained during the fourth alignment action S81. The first field of view 202 contains most of the semiconductor chip 20. Part 102 is a component used to hold the semiconductor chip 20 in position, such as a window clamper.

[0132] The fourth action S81 includes the following actions: The optical system is operated using the XY platform 11 in a manner that houses the first lead alignment point L1, the first chip alignment point A1, and the second chip alignment point A2 within the first field of view 202 (S81a). Next, a high-magnification image of the first field of view 202 is acquired using the first imaging device 30A (S81b). This image includes the first chip alignment point A1 and the second chip alignment point A2. Furthermore, a low-magnification image of the first field of view 202 is acquired using the second imaging device 31A (S81c). This image includes the first lead alignment point L1.

[0133] In the fifth action S82, the correlation between the tool XY platform 6 and the first camera device 30A is obtained. Furthermore, in the fifth action S82, the correlation between the tool XY platform 6 and the second camera device 31A is also obtained. The tool XY platform 6 is operated with reference point 21 housed in the second field of view 203 (S82a). Next, an image of the second field of view 203 is acquired (S82b). Next, the tool XY platform 6 is used and the tool is retracted.

[0134] The sixth action S83 includes the following actions: The optical system is operated using the XY platform 11 with the second lead alignment point housed in the first field of view 202 (S83a). Next, a low-magnification image of the first field of view 202 is acquired using the second imaging device 31A (S83b). The image includes the second lead alignment point.

[0135] In the seventh action S84, the correlation between the tool XY platform 6 and the first camera device 30A is obtained, and further, the correlation between the tool XY platform 6 and the second camera device 31A is obtained. The tool XY platform 6 is operated with reference point 21 contained in the second field of view 203 (S84a). Next, an image of the second field of view 203 is acquired (S84b). Next, the tool XY platform 6 is used to retract the tool containing reference point 21 (S84c).

[0136] Furthermore, with a sufficiently wide field of view, a binocular structure that includes both low-magnification and high-magnification optical path systems is unnecessary. That is, with a sufficiently wide field of view, a monocular structure is sufficient. Moreover, "monocular" and "binocular" can also be understood as the number of optical path systems with different magnifications.

[0137] <Effects>

[0138] The wire bonding apparatus 100 includes: a bonding platform 7 on which a semiconductor chip 20 is mounted; a wire bonding unit 40 having a capillary 1 for bonding wires 200 to the semiconductor chip 20, a Z-axis drive unit 5 for reciprocating the capillary 1, and a tool XY platform 6 for moving the capillary 1 and the Z-axis drive unit 5 along a two-dimensional plane intersecting the reciprocating direction; and a base 70 having an optical system 10 and an optical system XY platform 11 for moving the optical system 10 along a two-dimensional plane intersecting the reciprocating direction, and on which the wire bonding unit 40 is mounted. The wire bonding unit 40 is mounted on a first portion 71a of the base 70. The optical system XY platform 11 is mounted on a second portion 71b of the base 70, which is different from the first portion 71a.

[0139] In the wire bonding apparatus 100, the wire bonding unit 40 and the camera unit 50 are respectively mounted on different parts of the base 70. Thus, as before, the vibrations generated by the movement of the XY platform and the capillary drive unit act on the cantilever structure of the camera unit 50, preventing unexpected vibrations in the capillary 1. Since the vibrations caused by the movement of the camera unit 50 are sufficiently attenuated before reaching the wire bonding unit 40, they are unlikely to affect the movement of the wire bonding unit 40. Therefore, bonding can be performed in a good condition, thus suppressing any decrease in bonding quality.

[0140] In the wire bonding apparatus 100 of this embodiment, the positioning optical system 10 is not mounted on the same tool XY platform 6 as the bonding tool including the Z-axis drive unit 5. According to this structure, several advantageous effects are achieved. First, the mass borne by the tool XY platform 6 is reduced. Therefore, the load on the tool XY platform 6 is reduced. As a result, the travel time of the bonding tool can be further shortened, thus improving the processing time (UPH: Unit Per Hour) required for one processed part (unit). Furthermore, the system separating the camera unit 50 and the wire bonding unit 40 is simple and the distance is short. As a result, correction of thermal deformation caused by temperature changes between the camera unit 50 and the wire bonding unit 40 is easier.

[0141] Vibration of the optical system 10 and the Z-axis drive unit 5, which serves as the joint, can affect the control system. However, the positioning optical system 10 is not mounted on the same tool XY platform 6 as the joint tool. Therefore, the impact of vibration from the optical system 10 on the Z-axis drive unit 5 is suppressed. As a result, there is no need to set a time (vibration static timer) to wait for the vibration of the optical system 10, the Z-axis drive unit 5, and the tool XY platform 6 to decay. Therefore, UPH can be further improved. Moreover, the optical system 10 is not mounted on the high-speed tool XY platform 6. Therefore, the limitations on the shape and mass of the optical system 10 can be alleviated. As a result, new functions such as inspection can be incorporated into the optical system 10.

[0142] The wire bonding apparatus 100 of this embodiment also achieves the following effects. First, the mass of the part mounted on the tool XY platform 6 is reduced. Specifically, the mass of the camera unit 50 is reduced. As a result, the load on the motor driving the tool XY platform 6 can be reduced. For example, the load on the motor of the tool XY platform 6 can be approximately halved. As a result, as a simple calculation shows, the travel time can also be reduced by 30%. Therefore, the bonding speed can be further improved. As a result, the indicator representing the processing time (UPH: Unit Per Hour) required for one processed part (unit) can be improved.

[0143] Furthermore, the optical system 10 constituting the camera unit 50 needs to be mounted on a platform capable of high-speed movement. Therefore, to achieve high-speed movement, the camera unit 50 is subject to significant limitations in terms of shape, mass, and structure. However, by separating the camera unit 50 from the wire bonding unit 40, these limitations can be mitigated to some extent. As a result, components for implementing new functions such as inspection can be mounted in either the camera unit 50 or the wire bonding unit 40.

[0144] The vibration of the optical system 10 constituting the imaging unit 50 can be suppressed from affecting the control system of the wire bonding unit 40, including the capillary 1. As a result, the control of the wire bonding unit 40 becomes easier. Furthermore, the vibration of the optical system 10 constituting the imaging unit 50 will not affect the capillary 1, which serves as the bonding tool. As a result, the bonding performance can be improved. Moreover, when the effect of the vibration of the optical system 10 constituting the imaging unit 50 cannot be ignored, it is necessary to wait until the vibration generated in the various parts constituting the wire bonding apparatus 100 decays. However, the wire bonding apparatus 100 can suppress the effect of the vibration of the optical system 10 constituting the imaging unit 50. In other words, the effect of the vibration of the optical system 10 can be substantially ignored. Therefore, there is no need for a waiting time until the vibration decays. As a result, the UPH can be improved.

[0145] An image of reference point 21 of the tool XY platform 6 is obtained using a positioning optical system. The correlation between the optical system 10 and the tool XY platform 6 is obtained. By obtaining this correlation, changes in bonding offset caused by temperature variations, etc., can also be corrected. It can be used as an alternative to the function of photographing the position of the capillary 1's front end (Reference Positioning System, RPS). Therefore, the RPS function can be omitted from the wire bonding device 100. As a result, the bonding area in the Y direction can be expanded.

[0146] When performing temperature correction for the offset change, the main factors to consider are the movement of the reference point 21 and the movement of the first field of view 202. The movement of the reference point 21 is caused, for example, by the extension of the joining tool and the ultrasonic welding head 2. The movement of the first field of view 202 is caused, for example, by the extension of the front end portion of the optical system. The front end portion of the optical system is the portion closer to the object surface than the branch semi-transparent mirror. That is, the main factors to consider during correction are few and simple. Therefore, temperature correction can be easily performed.

[0147] In summary, the apparatus of this embodiment is a wire bonding machine that mounts a bonding tool on an XY platform 6, which serves as a movable platform. The wire bonding machine acquires images of the object to be bonded and a reference point 21 on the movable platform using an optical system located outside the movable platform. Furthermore, the positional relationship between the object to be bonded and the bonding tool is calculated using coordinates obtained from the images and coordinates of the movable platform.

[0148] The optical system of the wire bonding machine can be mounted on a movable platform. Furthermore, the wire bonding machine can also acquire images of the object to be bonded and the reference point 21 using the same camera device. Furthermore, in the wire bonding machine, the reference point 21 can be located on the ultrasonic welding head or welding head support. Furthermore, the wire bonding machine can also use the same lens to acquire images of the object to be bonded and the reference point 21.

[0149] The wire bonding apparatus 100 with the aforementioned structure can improve bonding speed, UPH (unified uptime), bonding accuracy, and bonding performance. Furthermore, the bonding area can also be expanded using the wire bonding apparatus 100.

[0150] The above describes the embodiments of the wire bonding device. The wire bonding device is not limited to the embodiments described herein.

[0151] <Examples of variations in optical path structures>

[0152] The desired structure can be used to make the optical path length from the first field of view 202 to the first camera device 30A and the second camera device 31A the same as the optical path length from the second field of view 203 to the first camera device 30A and the second camera device 31A. Figure 14 This illustrates an example of an optical path structure in this situation. For example... Figure 14 and Figure 15 As shown, a structure can also be used to bend the light path using multiple mirrors at uniform distances in the air. In addition to the structure of the imaging unit 50 described in this embodiment, the imaging unit 50A further includes an optical path length correction member 95. The imaging unit 50A may also include additional optical components 30C and 30D (see reference 30D) as needed. Figure 15 The optical path length correction component 95 is disposed between the semi-transparent mirror 37 and the semi-transparent mirror 38. The optical path length correction component 95 is as follows: Figure 15 As shown, multiple reflectors 41, 42, 43, and 44 are used to construct an optical path that undergoes four reflections. The optical path length is corrected according to the optical path structure. Alternatively, prisms can be used instead of reflectors 41, 42, 43, and 44.

[0153] Figure 16 The optical system 10B shown includes lenses 30E and 30F, and a light path length correction component 95A. The light path length correction component 95A is an optical component 96 comprising a material with a refractive index different from that of air disposed along the light path. The light path length correction component 95A includes a mirror for bending the light path and optical components with a refractive index different from that of air. According to the characteristics of the lenses, if the light path length from the image plane to the rear principal plane of the lens is shortened due to passing through the glass, the focusing position becomes shorter. Therefore, it is possible to achieve… Figure 16 That kind of structure.

[0154] Figure 15 The variations shown are similar to Figure 3 Unlike the modified example, when the reference point 21 is observed in the second field of view 203, the first field of view 202 is located directly above the capillary. That is, the camera offset value in the X direction is close to zero. Therefore, when the tool retracts from the state where the reference point 21 is observed in the second field of view 203, the joined object near the joint point can be directly observed in the first field of view 202. When using the structure described above, compared with... Figure 3 The modified examples shown simplify the structure and positioning method of the optical system.

[0155] The structure of the optical system 10 is not limited to a structure in which the optical path length from the first field of view 202 to the first imaging device 30A and the second imaging device 31A is the same as the optical path length from the second field of view 203 to the first imaging device 30A and the second imaging device 31A. A structure that focuses both the first field of view 202 and the second field of view 203 even if the optical path lengths are different can also be adopted. For example, the optical system may also be configured to include lenses, reflectors with curvature, or prisms.

[0156] Alternatively, a structure can be employed that mechanically moves the positions of optical elements such as lenses and mirrors. This structure provides an optical system capable of adjusting focus by driving the lens. An optical system capable of correction by changing the curvature of the optical elements can also be used. This type of optical system may employ liquid lenses. Furthermore, in the aforementioned case, the magnification of the first field of view 202 and the magnification of the second field of view 203 are not consistent in the stated state. Therefore, magnification correction is required.

[0157]

[0158] like Figure 17 As shown, the component for which reference point 21 is set is not limited to the ultrasonic welding head 2. For example, reference point 21A may also be set at the front end of the arm component, i.e., the welding torch arm 91, which is provided in a manner that protrudes from the tooling XY platform 6. Reference point 21B may also be set on the welding head support 4. Reference point 21C may also be set on the upper surface of the Z-axis drive part 5, which serves as a joint.

[0159]

[0160] The process of setting the camera offset value is not limited to Figure 10 The series of actions shown. Figure 18 This indicates another series of actions (step S9) that can be performed instead of step S3, which sets the camera offset value. In a modified example, image recognition is performed on a characteristic pattern. As a result, the camera offset value can be set without using reference point 21.

[0161] Figure 18 This is a process table detailing a variation of the process S9 for setting the camera offset value. The process S9 for setting the camera offset value includes: an eighth action S91 for setting the joint point, a ninth action S92 for joining or forming an indentation, and a tenth action S93 for calculating the joint position.

[0162] The eighth action S91 includes the following actions: The optical system is operated using the XY platform 11 with the semiconductor chip 20 housed in the first field of view 202 (S91a, S91b). Next, a reticle is used to set a junction point in the first field of view 202 (S91c). Next, calculations are performed (S91d). Specifically, the relative position of the set junction point with respect to a characteristic pattern in the first field of view 202 is determined. The relative position follows camera coordinates (Xb2', Yb2'). After the eighth action S91, the optical system retracts using the XY platform 11 (S91e). Next, the tool is operated using the XY platform 6 (S91f), and a reference point 21 is placed in the second field of view 203 (S91g). Next, image recognition is performed on the reference point 21 to determine the position of the reference point 21 within the second field of view 203 (S91h).

[0163] The ninth action S92 includes the following actions. The tool XY platform 6 is moved (S92a) by moving the capillary 1 to the engagement point. The moving distance is a value obtained by subtracting the offset of the reference point 21 relative to the center of the second field of view 203 obtained in S91 from the camera offset stored in the device. That is, the tool XY platform 6 moves in the same manner as if the reference point 21 were located at the center of the second field of view 203 and the stored camera offset had been moved. Next, the Z-axis drive unit 5 engages (S92b). Alternatively, an indentation-forming action can be performed instead of the engagement action. Then, the tool XY platform 6 retracts (S92c).

[0164] The tenth action S93 includes the following action: The optical system is operated using the XY platform 11 in such a way that the junction point is housed in the first field of view 202 (S93a).

[0165] Next, the junction point contained in the first field of view 202 is captured by camera (S93b). Next, calculation is performed (S93c). Specifically, the relative position of the set junction point with respect to the characteristic pattern in the first field of view 202 is determined. The relative position follows camera coordinates (Xb3', Yb3').

[0166] The camera offset value stored in the device is set to (Xc0, Yc0). The camera offset value can be the previously set value or the design value used during device manufacturing. The change in the camera offset value is based on the camera coordinates as (Xb3'-Xb2', Yb3'-Yb2'). The change in the camera offset value transformed into the coordinates of the tool's XY platform 6 is (Xb3-Xb2, Yb3-Yb2). As a result, the correlation between the position of the optical system's field of view center and the tool's descent position is (Xc, Yc) = (Xc0 + Xb3 - Xb2, Yc0 + Yb3 - Yb2).

[0167] <Other variations>

[0168] In this embodiment, the semiconductor chip 20, which is the object to be bonded, and the reference point 21 are imaged using a shared imaging device. For example, the wire bonding apparatus 100 may include an imaging device for acquiring an image of the object to be bonded and an imaging device for acquiring an image of the reference point 21, each as a separate device.

[0169] In this embodiment, the object to be joined is contained in the first field of view 202 to obtain an image, and the reference point 21 is contained in the second field of view 203 to obtain an image. For example, the object to be joined and the reference point 21 can also be contained in either the first field of view 202 or the second field of view 203 to obtain an image. That is, the first field of view 202 and the second field of view 203 can be combined to make it work.

[0170] Multiple images are obtained by taking multiple photos of the opening of the window fixture within the frame. Furthermore, these images can be composited and then joined using reference point 21 as a reference.

Claims

1. A wire bonding apparatus comprising: a bonding stage on which a bonding object is placed; a wire bonding unit having a capillary that bonds a bonding wire to the bonding object, a capillary drive section that reciprocally moves the capillary, and a first XY stage that moves the capillary and the capillary drive section along a two-dimensional plane intersecting a direction of the reciprocating movement; a camera unit having a camera section that captures an image of the bonding object placed on the bonding stage, and a second XY stage that moves the camera section along a two-dimensional plane intersecting the direction of the reciprocating movement independently of the first XY stage; and a base on which the wire bonding unit and the camera unit are mounted, the wire bonding unit is mounted to a first portion of the base, the camera unit is mounted to a second portion of the base different from the first portion, a reference point representing a position of the wire bonding unit is provided on a surface that can be imaged by the camera unit in the wire bonding unit.

2. The wire bonding apparatus according to claim 1, wherein the camera unit images the reference point and images the bonding object placed on the bonding stage.

3. The wire bonding apparatus according to claim 2, wherein the camera unit obtains a first image containing the reference point and a second image containing the bonding object and different from the first image.

4. The wire bonding apparatus according to claim 3, further comprising a control section that acquires a calibration value that calculates a correlation between a field coordinate of the reference point in the first image and a position coordinate of the first XY stage.

5. The wire bonding apparatus according to claim 4, wherein the reference point is provided on an upper surface of an ultrasonic horn of the wire bonding unit.

6. The wire bonding apparatus according to claim 5, wherein the camera unit has an imaging device and an optical system that constitutes the camera section, the optical system guiding light from the bonding object and the reference point to the imaging device, the optical system includes a lens and a light branching section disposed on an optical axis between the imaging device and the bonding object and between the imaging device and the reference point, the lens is disposed on the imaging device side, the light branching section is disposed on the bonding object side and the reference point side.

7. The wire bonding apparatus according to claim 6, wherein the light branching section includes a half mirror and an illumination that illuminates the half mirror with light, the light branching section switches a light path for acquiring the first image and a light path for acquiring the second image using the light illuminated to the half mirror. ​ 8. The wire bonding apparatus according to claim 4 or 5, wherein the control section calculates coordinates of the reference point based on the calibration value conversion in the second image, and drives the second XY stage in such a manner that the bonding point is included in the field of view for obtaining the first image, to obtain coordinates of the bonding point, and thereafter drives the first XY stage in such a manner that the reference point is included in the field of view for obtaining the second image, to obtain a camera offset value.

Images