JP2015015506A - Die bonder and die bonding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die bonder and a die bonding method having a short tact time and a high alignment accuracy by reducing the impact of vibration generated by conveyance operation or airflow produced by a heat source on an image captured for the purpose of positioning a work or a wafer.SOLUTION: Immediately after stopping the movement of a work or a die, an image pick-up device captures the image of the work or die in a shutter speed sufficiently longer than the fluctuation period (1 wavelength) of the waveform of a vibration before reaching a setting position and sufficiently longer than the wavelength of optical fluctuation due to airflow. An image processing section corrects the position by performing image processing where a blurred image thus captured is used for pattern matching.

Description

  The present invention relates to a die bonder and a die bonding method, and more particularly, to a die bonder and a die bonding method that reduce the alignment time.

In a conventional die bonding process, a package is assembled by mounting a semiconductor wafer (hereinafter simply referred to as a wafer) that has undergone a process of dividing a die (semiconductor chip; hereinafter simply referred to as a die) on a substrate such as a wiring board or a lead frame. .
In the die bonder, first, a substrate substrate such as a wiring substrate or a lead frame is carried in from a frame loader. A die adhesive is applied on the carried substrate substrate at the preform head portion (adhesive application step). The die adhesive is, for example, a paste adhesive.
The substrate substrate coated with the die adhesive is mounted (bonding step) on the die picked up from the wafer holder (pickup step) at the bonding portion.
At the time of the above-described adhesive application process, pick-up process, and bonding process, a substrate substrate and a wafer are imaged in accordance with each process, and positioning and inspection are performed by image processing based on the captured image (Patent Document 1). , Patent Document 2 and Patent Document 3).

JP 2002-72996 A JP 2003-318600 A JP-A-6-1973349

The substrate substrate is carried into a die bonder, die bonded, and then conveyed. That is, the substrate substrate is transported from the upstream to the downstream of the die bonder. Generally, in an industrial machine that requires high accuracy, it is naturally necessary to manage vibration and airflow inside the apparatus with high accuracy. However, in an industrial robot having a drive unit and a heat generating unit, it is physically difficult to eliminate these effects. In particular, a device such as a die bonder equipped with an image processing device is remarkably susceptible to these effects.
The vibration generated by the transfer operation is transmitted directly to the substrate substrate and also to the die bonder body. Further, not only the transfer operation but also the vibration generated for picking up in the pick-up process is mechanically transmitted into the die bonder. For example, the weight at the time of pickup is about 9.8 to 147 [m / s ² ].

In addition, after the preform process, the substrate is preheated to about 80 to 200 [° C.] in order to improve the applicability of the die adhesive.
Accordingly, there is air turbulence in the die bonder due to preheating or exhaust pipes. Furthermore, an air flow is generated in the die bonder due to a transport operation, a pickup operation, and the like.
In particular, when aligning, in the die bonder, the imaging device captures an image of a target (substrate substrate or die) to be aligned, and the image captured by the image processing device is image-processed to perform a target reference position (alignment mark). Is extracted. However, the location where the imaging device captures an image is close to the heat generation source, and the movement of the air current is intense. For this reason, the imaging apparatus is affected by optical fluctuation due to the movement of the airflow. Further, in order to acquire a bright image, the image is often picked up by increasing the luminance of illumination, but heat generated by irradiation with illumination light cannot be ignored.

In the first place, the image captured by the image capturing apparatus is used for alignment. If the position at the time of actual work is deviated from the position at the time when this image was captured, the captured image is inappropriate for alignment and cannot be used. Therefore, an image for alignment cannot be acquired until the substrate conveyance is finished and the vibration is reduced within a predetermined magnitude. For this reason, there has been a problem that the takt time of die bonding becomes long. Furthermore, due to optical fluctuations due to the influence of heat, there is a problem in that a time-determinable factor is included in the captured image, and the alignment accuracy is not improved.
In view of the above problems, an object of the present invention is to provide a die bonder and a die bonding method with a short tact time and high alignment accuracy.

In order to achieve the above object, a die bonder according to the present invention includes a first image pickup device that picks up a workpiece, an image picked up by the first image pickup device, and a predetermined first reference position of the workpiece. And a position control unit for positioning based on the extracted first reference position, wherein the first electronic shutter speed of the first imaging device is a reference for stopping the workpiece. It is longer than one wavelength of the first vibration waveform generated after stopping at the position or longer than one wavelength of the first waveform of the optical fluctuation at the stop reference position.
The die bonder of the present invention further includes a second imaging device that images the semiconductor chip before being held by the suction head, and the image processing unit performs image processing on an image captured by the second imaging device. A predetermined second reference position of the semiconductor chip is extracted, and the position control unit performs alignment based on the extracted second reference position, and a second electronic shutter speed of the second imaging device. Is longer than one wavelength of the vibration waveform generated after the semiconductor chip is stopped or longer than one wavelength of the first waveform of the optical fluctuation at the stop reference position.

The die bonder of the present invention includes a first imaging device that images a workpiece, and a drawing processing unit that performs image processing on an image captured by the first imaging device and extracts a predetermined first reference position of the workpiece. A position control unit that performs alignment based on the extracted first reference position, and the first electronic shutter speed of the first imaging device is generated after the workpiece has stopped at the stop reference position. It is longer than one wavelength of the first vibration waveform and longer than one wavelength of the first waveform of the optical fluctuation of the stop reference position.
The die bonder of the present invention further includes a second imaging device that images the semiconductor chip before being held by the suction head, and the image processing unit performs image processing on an image captured by the second imaging device. A predetermined second reference position of the semiconductor chip is extracted, and the position control unit performs alignment based on the extracted second reference position, and a second electronic shutter speed of the second imaging device. Is longer than one wavelength of the vibration waveform generated after the semiconductor chip is stopped and longer than one wavelength of the first waveform of the optical fluctuation at the stop reference position.

Furthermore, in the die bonder of the present invention, the first vibration waveform and the second vibration waveform include a time starting from a time when the semiconductor chip is stopped, the first reference position, and the second reference position. It is a vibration waveform obtained by measuring the offset from a plurality of times.

  Further, the die bonding method of the present invention includes a step of taking out the semiconductor chip by the suction head, and an optical longer than one wavelength of the first vibration waveform generated after the work is stopped at the stop reference position or at the stop reference position. The step of imaging by the first imaging device with the electronic shutter speed of the first imaging device being longer than one wavelength of the first waveform of fluctuation, image processing of the captured first image, and processing of the workpiece A die having a step of extracting a predetermined first reference position, and a step of die-mounting the semiconductor chip on the workpiece by alignment based on the extracted first reference position. Bonding method.

  According to the present invention, it is possible to provide a die bonder and a die bonding method with a short tact time and high alignment accuracy.

It is the conceptual diagram which looked at the die bonder of one Example of this invention from the top. It is typical sectional drawing for demonstrating the function of the imaging device in one Example of the die bonder of this invention. It is a figure for demonstrating one Example of the control system of the position alignment mechanism of this invention. It is a figure which shows an example of the vibration waveform generate | occur | produced when the unit of a drive part transfers from a movement to a stop. It is a figure which shows an example of the offset waveform by the optical fluctuation resulting from the airflow (turbulence of air) in the optical path from a workpiece | work or a wafer to an optical system. FIG. 5 is a diagram illustrating an embodiment of a die bonder and a die bonding method according to the present invention, which is for explaining the effect of fluctuation due to vibration by controlling the shutter speed of the imaging apparatus. FIG. 5 is a diagram illustrating an embodiment of a die bonder and a die bonding method according to the present invention, which is for explaining the effect of optical fluctuation caused by an air flow by controlling the shutter speed of the imaging apparatus. It is a figure explaining the image in one Example of the die bonder and die-bonding method of this invention of FIG. 6, FIG. It is a figure for demonstrating another calculation means and method of the shutter time which can remove the influence by a vibration in the die bonder and die bonding method of this invention. It is a figure explaining the vibration given to the image measured from the image which the imaging device imaged. It is a figure which shows that the intersection (black circle) of a vertical axis | shaft and a vibration waveform is a vibration generation timing and its coordinate. It is the schematic for demonstrating one Example of the calculation means and method of the shutter time which can remove the influence of the optical fluctuation by the airflow etc. in the die bonder and the die bonding method of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of each drawing, components having common functions are denoted by the same reference numerals, and the description thereof is omitted to avoid duplication as much as possible.

The basic configuration of the die bonder will be described with reference to FIG. FIG. 1 is a conceptual view of a die bonder according to an embodiment of the present invention as viewed from above. Reference numeral 100 denotes a die bonder, 11 denotes a wafer supply unit, 12 denotes a workpiece supply / conveyance unit, and 13 denotes a die bonding unit. As described above, the die bonder 100 includes the wafer supply unit 11, the workpiece supply / conveyance unit 12, and the die bonding unit 13.
In the wafer supply unit 11, 111 is a wafer cassette lifter, and 112 is a pickup device. In the workpiece supply / conveyance unit 12, 121 is a stack loader, 122 is a frame feeder, and 123 is an unloader. In the die bonding part 13, 131 is a preform part, and 132 is a bonding head part.

In FIG. 1, a wafer cassette lifter 111 has a wafer cassette (not shown) filled with wafer rings, and sequentially supplies the wafer rings to the pickup device 112. The pick-up device 112 moves the wafer ring so that a desired die can be picked up from the wafer ring.
The stack loader 121 supplies a work (lead frame) to which the die is bonded to the frame feeder 122. The frame feeder 122 conveys the workpiece to the unloader 123 via two processing positions on the frame feeder 122 (processing positions of the preform part and the die bonding part). The unloader 123 stores the conveyed work.
The preform part (die adhesive application device) 131 applies a die adhesive to a work (for example, a lead frame) conveyed by the frame feeder 122. The bonding head unit 132 picks up a die from the pickup device 112 and moves up to a bonding point on the frame feeder 122. Then, the bonding head unit 132 lowers the die at the moved bonding point, and bonds the die to the bonding point on the workpiece coated with the die adhesive. A film-like adhesive is also attached in advance to the back surface (adhesion surface) of the die.

With reference to FIG. 2, the basic functions of the image pickup apparatus used for the die bonder will be further described. FIG. 2 is a schematic cross-sectional view for explaining the function of the imaging device in an embodiment of the die bonder of the present invention. 2A is a diagram viewed from the lateral direction (Y direction), and FIG. 2B is a diagram viewed from the upper direction (Z direction). Note that FIG. 2 illustrates an imaging device in a die bonder and a captured image thereof. For this reason, illustration and description are omitted for functional parts (other components, connection) not related to the description. 232 is a processing position of the preform portion, 233 is a processing position of the die bonding portion, 211 is a wafer of a wafer ring mounted on the pickup device 112, 201 is an imaging device that images the die of the wafer 211 from above the pickup device 112, 212 Is a workpiece (for example, a lead frame) carried into the preform part 232, 202 is an imaging device for imaging the die bonding position (bonding point) of the preform part 131, and 213 is carried into the processing position 233 of the bonding head part. Reference numeral 203 denotes an image pickup apparatus that picks up an image of the die bonding position at the processing position 132 of the bonding head unit. Reference numeral 251 denotes a pitch between the processing position 232 of the preform unit and the die bonding unit 233. The workpieces 212 and 213 are carried from the loader while keeping the interval of the pitch 251 and conveyed to the unloader 123.
The imaging device is, for example, an imaging device using a CCD imaging device or a CMOS imaging device.

In FIG. 2, the imaging device 201 images the pattern surface (front surface) of the wafer 211 of the pickup device 112, and performs well-known image processing such as pattern recognition and the center position of one die and the suction nozzle of the pickup device 112. The position is corrected so as to eliminate the deviation from the center and the center position of the push-up block.
Similarly, the imaging device 202 images a predetermined die bonding position (bonding point) of the preform portion 232 and positions the preform resin to be applied to the die bonding position by known image processing such as pattern recognition. Deviation correction is performed and preform resin is applied.
Similarly, the imaging device 203 captures an image of a predetermined die bonding position of the die bonding unit 233 and corrects misalignment so that the die is mounted at the center position of the die bonding position by known image processing such as pattern recognition. And mount the die.

When the image processing device acquires an image with the imaging device (electronic shutter: during accumulation exposure), the image processing device is affected by vibrations caused by the die bonder itself and turbulence of the air current, and the reproducibility of the captured image is Fluctuation occurs. Shake can be suppressed by reducing the shutter speed against vibration. However, the position is indefinite within the amplitude range. That is, the position based on the captured image (position at the time of imaging) moves by subsequent vibration, and the current position is different from the position at the time of imaging.
These phenomena reduce the positioning function using image processing, and ultimately the bonding accuracy is lowered.

  Next, the positional deviation correction will be further described with reference to the alignment mechanism shown in FIG. FIG. 3 is a diagram for explaining an embodiment of the control system of the alignment mechanism of the present invention. Reference numeral 301 denotes an image processing device, 302 denotes a position control device, 303 denotes an X-axis drive unit, 304 denotes a Y-axis drive unit, 305 denotes a θ-axis drive unit, 306 denotes an X-axis motor, 307 denotes a Y-axis motor, and 308 denotes a θ-axis motor. It is.

In FIG. 3, the imaging apparatus 201 captures an image of the pattern surface (front surface) of the wafer 211 and outputs the captured image data to the image processing apparatus 301.
The image processing apparatus 301 analyzes the input image data by known image processing such as pattern recognition, and extracts deviations in the X, Y, and θ coordinates of the alignment marks at predetermined locations on the wafer and the die. Then, the position correction amount is calculated so that the center 300 of the die to be picked up is at the center position of the pickup, and the calculated position correction amount is output to the position control device 302.
The position control device 302 outputs a control signal to the drive units 303 to 305 based on the input position correction amount. The drive units 303 to 305 control the respective motors (X-axis motor 306, Y-axis motor 307, and θ-axis motor) based on the input control signal, and set the X coordinate, Y coordinate, and θ (rotation) coordinate. to correct.
In the above-described embodiment, the position correction for the pickup device 112 has been described. Hereinafter, the same applies to the preform portion 131 and the bonding head portion 132.

Next, with reference to FIG. 4, a description will be given of vibrations that occur at the timing when the drive unit shifts from movement to stop (the conveyance operation stops and the workpiece stops at the stop reference position). FIG. 4 is a diagram illustrating an example of a vibration waveform generated when the unit of the drive unit shifts from movement to stop.
Note that, as described in FIG. 2, in the present invention, as the process in which the drive unit stops moving and the imaging device determines the position by image processing, in the present invention, (1) the pickup device from the wafer cassette lifter 111 of the pickup device 112 is used. The movement of the wafer ring to 112 and the movement of the die position in the pickup device 112, (2) loading of the workpiece 212 into the preform portion 232, and (3) loading of the workpiece 213 into the die bonding portion 232. In the following description, (3) loading of the workpiece 213 into the die bonding unit 232 will be described as an example.

  In FIG. 4, the horizontal axis indicates time, and the vertical axis indicates an offset from the reference position (settling position). FIG. 4A shows that the workpiece 213 is moving at time t41 and stopped at the stop reference position at time t42 (the workpiece transfer operation is stopped). However, the workpiece 213 does not stop completely at time t42 due to vibration, and vibrates in the workpiece conveyance direction around the stop reference position. The amplitude of vibration (deviation from the stop reference position) gradually decreases with time, and falls within a predetermined allowable amplitude value (settling value) when the settling time elapses. That is, unless the positional relationship of the shape of the rigid portion of the drive unit that moves and stops the workpiece 213 changes significantly, in other words, unless the positional relationship between the vibration fulcrum portion and the measurement point changes significantly, the vibration cycle is somewhat constant. Thus, the amplitude attenuates transiently and converges.

Next, as illustrated in FIG. 4B, for example, the imaging apparatus acquires an image of the workpiece 213 at the timing of time t43, performs image processing on the acquired image, and determines a position based on the alignment mark. As a result, the workpiece 213 is aligned at a position shifted by a distance d as compared with the position at the time of convergence (true value: stop reference position value with zero offset). For this reason, position correction for the offset value (distance d) is further required.
In the die bonding step, the work 213 is already at the convergence position (a settling position almost close to the stop reference position) before the suction nozzle mounts the die at a predetermined position on the work 213. Similarly, in the preform part 131, the work 212 is already in the settling position before the application head for applying the die adhesive is applied to the work 212. Similarly, in the pickup device 112, the center position of the die is already in the settling position before the pickup nozzle of the pickup device picks up the die.
However, in order to increase the position accuracy, after waiting until time t45 when the attenuation is almost eliminated, the image of the work 213 is acquired by the imaging device, the acquired image is processed, and the position is determined. Since a lot of time is required, the tact time becomes long.

  As shown in FIG. 4C, a die bonder capable of calculating a true value more accurately than before in the section of a short time T40 from the workpiece stop time t42 to time t44 will be described below.

Next, the optical fluctuation caused by the airflow (air turbulence) in the optical path from the workpiece or wafer to the optical system will be described with reference to FIG. This optical fluctuation is caused by temperature change, blown air, or the like. FIG. 5 is a diagram illustrating an example of an offset due to optical fluctuation caused by an airflow (air turbulence) in an optical path from a workpiece or wafer to the optical system. 5A and 5B, the horizontal axis represents time, and the vertical axis represents the offset from the reference position.
FIG. 5A is a diagram showing an example of an offset amplitude waveform that is generally generated by an airflow in the optical path in the die mounter. The generation timing (cycle) and amplitude of the peaks P _{A1 and} valley P _A2 are close to random, but the maximum amplitude value A _max and the maximum cycle value L _max are within a predetermined range.
FIG. 5B is a diagram in which the amplitude at the time when the imaging is repeatedly performed with respect to the amplitude waveform of the fluctuation of the amplitude waveform in FIG. 5A is indicated by dots P _{1 to} P ₄ .
FIG. 5C is a diagram in which the amplitude value of the fluctuation every time the image is taken as shown in FIG. The horizontal axis indicates the frequency, and the vertical axis indicates the class representative value of the amplitude (for example, the median is zero offset).
Thus, the variation in amplitude can be expressed by a standard deviation that depends on the probability distribution.

Now, an embodiment of the die bonder and die bonding method of the present invention will be described with reference to FIG. FIG. 6 is a diagram illustrating an embodiment of a die bonder and a die bonding method according to the present invention, in which the effect of fluctuation due to vibration is removed by controlling the shutter speed of the imaging device. The horizontal axis represents time, and the vertical axis represents the offset from the reference position.
FIG. 6A shows the relationship between the blur width w, the blur width center c, and the offset reference position (settling position) when the electronic shutter time (accumulation time) of the imaging apparatus is relatively short with respect to one wavelength of vibration. FIG. The blur width w is the difference between the “offset maximum value” and the “offset minimum value” within the shutter time.
w = "maximum offset value"-"minimum offset value"
Accordingly, the position of the blur width center c is a value that is ½ of the sum of the “maximum offset value” and the “minimum offset value” within the shutter time.
c = (“offset maximum value” + “offset minimum value”) / 2
FIG. 6B shows the relationship between the blur width w, the blur width center c, and the offset reference position (settling position) when the electronic shutter time (accumulation time) of the imaging device is sufficiently short for one wavelength of vibration. FIG. Although the blur width w is small, the blur width center c is indefinite within the range of the amplitude relative to the settling position. If the vibration and shutter cannot be synchronized, the position cannot be determined.
FIG. 6C is a diagram showing the relationship between the blur width w, the blur width center c, and the offset reference position (settling position) when the electronic shutter time (accumulation time) of the imaging apparatus is sufficiently longer than one wavelength of vibration. It is. Although the fluctuation width w increases, the fluctuation range of the fluctuation width center c is an absolute difference between the “maximum positive offset absolute value” and the “maximum negative offset absolute value” on the plus side with respect to the settling position. The value becomes ½ of the absolute value of the difference between “maximum of positive offset absolute value” and “maximum of negative offset absolute value” on the minus side.
± | “Maximum absolute value of positive offset” − “Maximum absolute value of negative offset” | / 2
For vibrations with relatively stable amplitude, the value is small.

An embodiment of the die bonder and die bonding method of the present invention will be described with reference to FIG. FIG. 7 is a diagram illustrating an embodiment of a die bonder and a die bonding method according to the present invention, in which the shutter speed of the imaging device is controlled to remove the influence of optical fluctuation caused by the airflow.
It can be considered that the optical fluctuation caused by the airflow usually occurs randomly when there is no tendency to the airflow or the density. In the present example, the optical fluctuation due to the airflow was considered to occur randomly, and the following examination was made.
That is, the positions by image processing are distributed with a constant probability distribution with respect to the true value. For this reason, the probability that the settling position exists near the center of the fluctuation waveform as shown in FIG. 7 is the highest. By providing a shutter time (accumulation time) that is as long as possible to calculate the variance, image data with the true value as the center is obtained. The true value of this image data can be calculated more accurately than an image captured with a short shutter time.

FIG. 8 is a diagram illustrating an example of image data with respect to the shutter time described with reference to FIG. 6 or FIG. FIG. 8 shows that (a) the shutter time is sufficiently short with respect to the fluctuation period (one wavelength), (b) the shutter time is relatively short with respect to the fluctuation period (one wavelength), and (c) the shutter time. For a case where the period is sufficiently long with respect to the fluctuation period (one wavelength), an image at the time of template registration and an image at runtime time are shown.
In FIG. 8A, each image is not blurred. However, the center position is not fixed. The runtime image is different from the template registered image.
In FIG. 8B, each image is blurred. Therefore, the center position is not fixed. The runtime image is different from the template registered image.
In FIG. 8C, each image is blurred. However, the center position is close to the actual center position. Further, the runtime image is similar to the template registered image.
That is, as explained in FIG. 6, FIG. 7, and FIG. 8, at the time of runtime or in addition to the template image registration, the shutter time is sufficiently long with respect to the fluctuation period (one wavelength), and pattern matching is performed with a blurred image. Image processing algorithm. As a result, the blur center is close to the true value. As a result, positioning accuracy is improved.

Another embodiment of the die bonder and die bonding method of the present invention will be described with reference to FIG. In the first embodiment, an image processing algorithm is used in which an image is acquired with a shutter speed sufficiently longer than the fluctuation wavelength of the shutter time and pattern matching is performed with a blurred image.
With reference to FIG. 9, another means and method for calculating the shutter time capable of removing the influence of vibration will be described. FIG. 9 is a view for explaining an embodiment of the die bonder and the die bonding method of the present invention. Reference numeral 901 denotes an image pickup apparatus using a CCD image pickup element or a CMOS image pickup element, 905 denotes an optical axis of the image pickup apparatus 901, 914 denotes a lens, 911 denotes an optical axis 905 of the image pickup apparatus 901, and the image pickup element (upper side of the image pickup apparatus 901) side. Reference numeral 912 denotes a sensor provided on the optical axis 905 of the imaging device 901 and on the lens 914 side (lower side of the imaging device 901). Reference numeral 901 ′ denotes an image pickup apparatus using a CD image pickup element or a CMOS image pickup element, 905 ′ denotes an optical axis of the image pickup apparatus 901 ′, 914 ′ denotes a lens, and 911 ′ denotes an optical axis 905 ′ of the image pickup apparatus 901 ′. A sensor provided on the element (upper side of the imaging device 901 ′) side, 912 ′ is a sensor provided on the optical axis 905 ′ of the imaging device 901 ′ and on the lens 914 ′ side (lower side of the imaging device 901 ′). is there.

In the embodiment of FIG. 9, a method of measuring a vibration waveform by shutter opening (accumulation start and end) timing control will be described. That is, the vibration period or vibration end time is calculated for vibration suppression.
As a sensor to be used, an acceleration sensor and a vibration sensor are generally considered. However, the measurement with the vibration sensor may make it difficult to confirm the influence on the captured image for the following reason.
That is, FIG. 9A is a schematic diagram in which the optical axis of the imaging device 901 is set so as to be in the vertical direction. FIG. 9B is a schematic diagram when the optical axis is slightly rotated (angle θ) from the imaging device 901 whose optical axis is vertical due to vibration.
When two upper and lower vibration sensors are mounted on the optical axis, (1) there is no response when the sensor is at the center of rotation, and (2) no offset is reflected when the optical system has a long optical path. , Etc.
In general, an acceleration sensor cannot calculate an offset, but can be analogized by integrating the extracted waveform. However, even if the acceleration sensor is used in accordance with FIG. 9, it is difficult to accurately calculate the offset on the image. Therefore, the optimum shutter time is determined by measuring the influence on the actual image from the measurement result of the sensor. Select.

  The embodiment of FIG. 9 will be further described with reference to FIG. FIG. 10 is a diagram for explaining vibrations applied to an image measured from an image captured by the imaging apparatus. The horizontal axis indicates time, and the vertical axis indicates offset. FIG. 10A is a diagram showing the relationship between the frame cycle (vertical synchronization: VD) and the shutter speed for the vibration waveform of one continuously captured image. FIG. 10B is a diagram in which vibration waveforms of images captured at the first time, the second time, and the third time are shown together.

  In FIG. 10, the influence of repeated apparatus vibrations on an image can be measured by the imaging apparatus. An image is generally picked up by an image pickup apparatus using an image pickup device such as a CCD image pickup device or a CMOS image pickup device. However, the captured image cannot be repeatedly imaged at a period higher than the image ejection time (image transfer time) of the image sensor. Therefore, the captured image cannot maintain its continuity accurately. For this reason, it is generally difficult to use for analysis of trajectory such as vibration. That is, as shown in FIG. 10A, even if the shutter time s can be shorter than the frame cycle VD, the timing depends on the frame cycle. For this reason, the continuity of the video cannot be maintained.

However, in one embodiment of the present invention, in measuring the shutter time, it is important to accurately measure how an actual image captured by the imaging device is affected by vibration. For this reason, as shown in FIG. 10B, in the second embodiment, the operation reproducibility of the apparatus is used.
FIG. 11 is a diagram showing that the intersection (black circle) between the vertical axis and the vibration waveform is the vibration generation timing and its coordinates. The horizontal axis indicates time, and the vertical axis indicates the offset from the reference position.
1 (a) is the first measurement, FIG. 11 (b) is the second measurement, FIG. 11 (c) is the third measurement,..., FIG. 11 (d) is the Nth measurement. 2 or more natural numbers).
When the cause of occurrence is always the same and the apparatus has sufficient rigidity, the trajectory drawn by the vibration is highly reproducible at the level at which period measurement is performed.
As a result, the vibration period, amplitude, and decay time can be measured, and the shutter time for the required accuracy can be calculated.
In other words, no matter how many times the vibration waveform is generated, the reproducibility is great if the rigidity of the apparatus is high. As a result, the shutter speed and shutter timing can be determined by the fact that the vibration period and the amplitude range are substantially constant. For this reason, positioning accuracy is improved by measuring the vibration according to the second embodiment and applying the first embodiment using the measured vibration waveform. As a result, the bonding accuracy is improved.

Another embodiment of the die bonder and die bonding method of the present invention will be described with reference to FIG. FIG. 12 illustrates an embodiment of a shutter time calculation means and method capable of removing the influence of optical fluctuations caused by an air current and the like when carrying out the embodiment 1 of the die bonder and die bonding method of the present invention. FIG. That is, FIG. 12 is a diagram for explaining means and a method for measuring the shutter time necessary for removing the influence of airflow by repeated recognition. The horizontal axis indicates the shutter time, and the vertical axis indicates the standard deviation.
In FIG. 12, image processing such as pattern matching is performed with the apparatus stopped. “Image capture” and “position detection” are repeatedly executed. Thus, the detection variation (detection accuracy) is measured.
That is, by repeatedly executing the “image capture” and “position detection” while changing the shutter time, the tendency of detection accuracy at each shutter time can be measured.
The tendency of the detection accuracy for each shutter time is determined by the fluctuation trend tendency. If the shutter time is not sufficiently obtained in comparison with the fluctuation cycle, the repeatability deteriorates (shutter time is less than point s0). If the shutter time is extended beyond the point s0, the accuracy becomes stable (the shutter time is more than the point s0 and less than the point s1). Thereby, the required shutter time (for example, point ss) with respect to required accuracy can be calculated.

  As a result, the positioning accuracy is improved by measuring the fluctuation of the airflow according to the third embodiment and applying the first embodiment or the second embodiment using the measured shutter speed-standard deviation waveform of the positioning accuracy. That is, as a result, bonding accuracy is improved.

  The present invention is not limited to a die bonder, and can be applied to a semiconductor manufacturing apparatus such as a wire bonder, a chip mounter, a dispenser, a beam soldering apparatus, and a sealing apparatus that have a drive mechanism and a conveyance system and perform alignment by image processing. The present invention can also be applied to an apparatus that does not have a heat generating portion.

  DESCRIPTION OF SYMBOLS 11: Wafer supply part, 12: Workpiece supply / conveyance part, 13: Die bonding part, 100: Die bonder, 111: Wafer cassette lifter, 112: Pickup device, 121: Stack loader, 122: Frame feeder, 123: Unloader, 131 : Preform section, 132: Bonding head section, 201: Imaging apparatus, 202: Imaging apparatus, 203: Imaging apparatus, 211 :: Wafer, 212, 213: Workpiece, 232: Processing position of preform section, 233: Die bonding 305: Pitch, 301: Image processing device, 302: Position control device, 303: X-axis drive unit, 304: Y-axis drive unit, 305: θ-axis drive unit, 306: X-axis motor, 307: Y-axis motor, 308: θ-axis motor, 901, 90 ': Imaging apparatus, 905,905': optical axis, 911, 911 ', 912,912': sensor 914, 914 ': lens.

Claims (10)

An imaging device; and an image processing unit that performs image processing on an image captured by the imaging device and extracts a predetermined reference position of the imaging target;
A position control unit for aligning based on the extracted reference position,
A die bonder having apparatus rigidity to such an extent that fluctuation of the imaging object has periodicity, wherein an electronic shutter time of the imaging apparatus is longer than a measured period of fluctuation of the imaging object. An imaging device; and an image processing unit that performs image processing on an image captured by the imaging device and extracts a predetermined reference position of the imaging target;
A position control unit for aligning based on the extracted reference position,
A die bonder, wherein an electronic shutter time of the imaging device is longer than a measured fluctuation cycle of the subject to be imaged that fluctuates due to blowing air. The die bonder according to claim 1, wherein the period is calculated based on a plurality of times of imaging of the imaging target of the imaging apparatus. An imaging device; and an image processing unit that performs image processing on an image captured by the imaging device and extracts a predetermined reference position of the imaging target;
A position control unit for aligning based on the extracted reference position,
The die bonder according to claim 1, wherein the electronic shutter time of the imaging device is calculated based on an image captured a plurality of times by changing the electronic shutter time. The die bonder according to claim 4, wherein imaging is performed at a required shutter time with respect to a required accuracy based on a tendency of detection accuracy at each shutter time of the image captured a plurality of times. Imaging with an electronic shutter time longer than the measured fluctuation period of the imaged object imaged in a die bonder with a device rigidity to such an extent that the imaged object fluctuation has periodicity;
Image-processing the captured image and extracting a predetermined reference position of the imaging target;
Aligning based on the extracted reference position;
A die bonding method characterized by comprising: Imaging with an electronic shutter time longer than the measured fluctuation cycle of the subject to be shaken due to the blown air;
Image-processing the captured image and extracting a predetermined reference position of the imaging target;
Aligning based on the extracted reference position;
A die bonding method characterized by comprising: 8. The die bonding method according to claim 6, wherein the period includes a step of calculating based on information of target imaging measured by imaging a plurality of times of imaging of an imaging target that is an object of the imaging step. 9. Imaging with a long electronic shutter time calculated based on an image captured multiple times with varying electronic shutter time;
Image-processing the captured image and extracting a predetermined reference position of the imaging target;
Aligning based on the extracted reference position;
A die bonding method characterized by comprising: The die bonding method according to claim 9, wherein imaging is performed at a necessary shutter time with respect to a required accuracy based on a tendency of detection accuracy at each electronic shutter time of the image captured a plurality of times.

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