KR101165028B1 - Light calibration method of wire bonder - Google Patents

Abstract

The present invention provides a method of adjusting the lighting of the wire bonder. The method of adjusting the illumination of the wire bonder includes setting a brightness reference value of a light source projected on a material, and adjusting an amount of current supplied to the light source based on the reference value. Therefore, according to the lighting adjustment method of the wire bonder of the present invention, when the same parameter input value is input to the lighting devices of the respective wire bonders, regardless of the deviation of the components provided in the lighting devices of the wire bonders, the respective lighting devices The light sources provided in the can emit light with the same brightness.

Description

Light calibration method of wire bonder

1 is a side view showing an example of a conventional wire bonder.

2 is a circuit diagram showing the configuration of a lighting device of a conventional wire bonder.

Figure 3 is a block diagram showing an embodiment of a method for adjusting the illumination of the wire bonder according to the present invention.

FIG. 4 is a detailed block diagram illustrating a reference value setting step of FIG. 3.

FIG. 5 is a detailed block diagram illustrating the current amount adjusting step of FIG. 3.

DESCRIPTION OF REFERENCE NUMERALS

10: capillary

20: LED

30: camera

80: die

90: material

The present invention relates to a method used for wire bonding, and more particularly, to a method for adjusting the illumination of a wire bonder for automatically adjusting the brightness of the illumination irradiated to the material side during wire bonding.

In general, a process of manufacturing a semiconductor package includes a wire bonding process of connecting a pad of a semiconductor chip (hereinafter referred to as a “die”) and a lead of a lead frame with a bonding wire having good conductivity such as gold or silver. This is mainly done by wire bonders.

The wire bonder loads the die attach lead frame material into a bonding zone where actual wire bonding is performed, and then loads the loaded lead frame material into an upper window clamp and a lower heater. The wire bonding operation is performed after fixing to the block, and after the operation, the process is performed by unloading the bonded lead frame material.

Meanwhile, the wire bonding operation is an operation of electrically connecting pads formed very closely to each die and leads corresponding to the pads, and to prevent a short between the other leads. Work must be done with high precision.

Therefore, the wire bonder uses a pattern recognition system provided therein to increase such precision. That is, the pattern recognition system of the wire bonder is looking for a reference pattern pre-teached in the lead frame material loaded by using a light source such as a light emitting diode (LED) and a camera, and the wire bonder is located at the position of the found reference pattern. In this way, the bonding accuracy is improved by selectively correcting the position of the lead frame material and then performing the bonding operation.

1 is a side view showing an example of a conventional wire bonder.

Referring to FIG. 1, a conventional wire bonder includes a material transfer device (not shown) for loading or unloading a material 90 to be bonded, that is, a lead frame material 90 to which the die 80 is attached. Including an LED (20) used as a light source and the illumination device for irradiating light to the loaded material 90 side to recognize the reference pattern of the material (90) loaded by the material transport device, and the camera 30 And a pattern recognition unit which detects the reflected light of the light irradiated to the material 90 side by the illumination device to recognize the reference pattern formed on the material 90 and transmits the recognition value to a central controller (not shown) which will be described later. A material position correction device (not shown) for selectively correcting the position of the loaded material 90 according to the value recognized by the pattern recognition unit, and a pad formed on the die 80 when the position of the material 90 is corrected ( While quickly reciprocating between the 85 and the lead 95 of the lead frame 90 Overall control of the capillary 10 and the wire bonder, which electrically connects the pad 85 of the teeth 80 and the lead 95 of the lead frame 90 through the wire 15 or the like. It includes a central control unit.

Therefore, the central controller proceeds with the wire bonding process by controlling the capillary 10 and the lighting apparatus as a whole through the values recognized by the pattern recognition unit.

2 is a circuit diagram showing the configuration of a lighting device of a conventional wire bonder.

As shown in FIG. 2, the lighting apparatus of the conventional wire bonder is used to adjust a current input to the LED 20 as a light source according to a user's input parameter.

That is, the conventional lighting device of the wire bonder, as shown in FIG. 2, the current input unit 47 for outputting a constant current value according to the LED (20), the light source and the input voltage value and input it to the LED (20) And a voltage input unit 48 for outputting a predetermined voltage value according to a user input parameter and inputting the same to the current input unit 47.

Therefore, when a user inputs a constant value parameter through the VME 41 of the voltage input unit 48, the DAC 42 outputs a constant voltage value according to this input parameter, and the current input unit 47 outputs a constant voltage value. ) Is input to the OP AMP 43, and the current input unit 47 outputs a constant current value according to the input voltage value and inputs it to the LED 20, and the LED 20 is input as described above. According to a constant current value, light is emitted at a predetermined brightness to illuminate the loaded material.

In this case, if the DAC 42 uses 8 bits of data, the user may have a parameter input value of 0 to 255, and the current value input to the LED 20 at this time is represented by Equation 1 below. Will be available.

Therefore, when an 8-bit DAC 42 having a maximum of 5V is used and the user inputs 128 as a parameter input value, 128/255 * 5V, that is, 2.5V is input to the OP AMP 43 of the current input unit 47, and the current The input unit 47 outputs a constant current value at 2.5V / resistance value 45 and inputs it to the LED 20. Thus, the LED 20 emits light at a predetermined brightness according to a predetermined current value input as described above to illuminate the loaded material.

However, in the case of the lighting device of the conventional wire bonder, the actual current capacity supplied to the LED 20 according to the deviation of the components provided in each lighting device, for example, the deviation of the components such as the DAC 42, TR 44, etc. Since it is different, when the same parameter input value is input to the lighting devices of the respective wire bonders, the brightness of the LED 20 provided in each lighting device may be changed for each lighting device.

Therefore, the cameras 30 in each lighting device that detects the reflected light of the light irradiated from the LED 20 to the material 90 side and recognizes the reference pattern formed in the material 90 also show that the brightness of the LED 20 is different. This causes a problem that the recognition value of the reference pattern can show a big difference for each lighting device.

Therefore, the present invention has been made in view of the above problems, and the technical problem to be achieved by the present invention, regardless of the deviation of the components provided in the lighting apparatus of each wire bonder, the lighting apparatus of each wire bonder In the case of inputting the same parameter input value, it is to provide a method of adjusting the illumination of the wire bonder so that the light sources provided in each of the lighting devices emit light with the same brightness.

The lighting adjustment method of the wire bonder of the present invention for implementing the above technical problem comprises the steps of setting the brightness reference value of the light source shined on the material, and adjusting the amount of current supplied to the light source based on the reference value do.

In another exemplary embodiment, the setting of the brightness reference value may include inputting a fine current into the light source, and reading the light of the light source emitted by the input current value by an analog to digital converter (ADC) inside the camera. Determining whether the maximum value is readable by the ADC, storing the converted value of the ADC in the equipment relative to the current value input to the light source and the input current value if the maximum value is readable by the ADC; Dividing the conversion value of the ADC into a plurality of steps based on the memory value, and setting a reference value for each divided step.

In another embodiment, the step of setting the brightness reference value is input to the light source so that the ADC reads again to determine again whether the ADC is the maximum value that the ADC can read, unless it is the maximum value that the ADC can read. The method may further include increasing the amount of current.

In another embodiment, adjusting the amount of current includes inputting a parameter in each divided step, and determining whether a conversion value of the ADC by the input parameter is within an allowable range of the reference value of the step. The method may include storing an input parameter satisfying the reference value for each step if the converted value of the ADC is within the allowable range of the reference value of the step.

In another embodiment, the step of adjusting the amount of current may again determine whether the conversion value of the ADC is within the allowable range of the reference value of the step, if the conversion value of the ADC is not within the allowable range of the reference value of the step. The method may further include increasing the input parameter to determine.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments disclosed herein are being provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. Like numbers refer to like elements throughout.

Figure 3 is a block diagram showing an embodiment of the lighting adjustment method of the wire bonder according to the present invention, Figure 4 is a block diagram showing in detail the step of setting the reference value of Figure 3, Figure 5 is a current amount adjustment of Figure 3 A block diagram showing the steps in detail.

3 to 5, the method of adjusting the illumination of the wire bonder according to an embodiment of the present invention comprises the steps of setting the brightness reference value of the light source shined on the material (S100), and based on the reference value to the light source Adjusting the amount of current supplied (S200).

In this case, the setting of the brightness reference value (S100) includes inputting a fine current to the light source (S110), and converting the light of the light source emitted by the input current value into an analog to digital converter (ADC) in a camera. Determining whether the ADC reads the maximum value, that is, the value saturated at AD conversion (S120), and if the ADC does not read the maximum value based on the determination value, the ADC reads the ADC again. Further increasing the amount of current input to the light source to re-determine whether is the maximum value that can be read (S130), the current value input to the light source and the input if the maximum value that can be read by the ADC by the determination value Storing the converted value of the ADC in the device relative to the current value (S140), and if the converted value of the ADC is stored in the device, The step of dividing into a system (S150), and the step of setting a reference value for each divided step (S170).

The adjusting of the amount of current (S200) includes inputting a parameter in each divided step (S210), and determining whether a conversion value of the ADC by the input parameter is within an allowable range of the reference value of the step. In step S230, if the converted value of the ADC is not within the allowable range of the reference value of the step based on the determination value, the input is further determined to determine whether the converted value of the ADC is within the allowable range of the reference value of the step. Further increasing the set parameters (S250), and storing the input parameters satisfying the reference values of each step (S270) if the converted value of the ADC is within the allowable range of the reference value of the step by the determination value. Include.

For example, when a minute current is input to the light source, that is, the LED (S110), the LED emits light according to the input current value, and the ADC of the camera provided in the pattern recognition unit reads the emitted light. It is determined whether the ADC can read the maximum value, that is, the value that is saturated during AD conversion (S120). At this time, if the ADC is 8 bits, the maximum value that the ADC can read is 255. Therefore, the ADC of the camera reads the light emitted from the LED and if the value is not the maximum value, increases the amount of current supplied to the LED until the maximum value 255 is read (S130), and if the read value is the maximum value If the value, the current value input to the light source and the converted value of the ADC compared to the input current value is stored in the equipment (S140).

Next, since the value read by the ADC of the camera is the maximum value, when the current value inputted to the light source and the converted value of the ADC compared to the input current value are stored in the device (S140), the ADC is stored in a plurality of steps based on the stored value. For example, when it is based on 255, it is divided into 16 steps (steps 0 to 15) so that there is a difference of about 16 for each step (S150), and the reference value is set for each divided step (S170). ). For example, in step 0, the ADC conversion value is set to 16 so that the ADC conversion value based on the input current value is 16. In step 5, the ADC conversion is performed so that the ADC conversion value based on the input current value is 96. Set the value to 96.

On the other hand, if some wire bonder equipment needed 5mA to set the 0 stage ADC conversion value 16, other wire bonder equipment may need 10mA to set the 0 stage ADC conversion value 16. However, since the current values 5mA and 10mA are input values of the equipment, assuming that the current value and the parameter input value are the same, the input parameters are 5 and 10, and thus the common parameters between the devices cannot be used.

Therefore, adjusting the amount of current in the lighting adjustment method of the wire bonder of the present invention (S200) allows such equipment to use a common parameter between the equipment.

That is, in the current amount adjustment step (S200) according to the present invention, the first device inputs parameter 5 as it is so that the above two devices read the 0-step ADC conversion value as 16, and supplies 5 mA to the LED, and the second device as it is. Enter 5 and the remaining 5 will automatically add 5 in software to supply 10mA to the LEDs.

Therefore, according to the present invention, when inputting the same parameter input value to the lighting devices of the respective wire bonders, regardless of the deviation of the components provided in the lighting devices of the respective wire bonders, the light sources provided in the respective lighting devices are It is possible to emit light with the same brightness.

Therefore, according to the present invention, since the light sources provided in the respective lighting devices, that is, the LEDs emit light with the same brightness irrespective of the deviation of the components provided therein, the reflected light of the light irradiated from the LED to the material side is detected. The cameras in each lighting apparatus that recognizes the reference pattern formed in the conventional apparatus may recognize the reference pattern with the same brightness, that is, the same reference, and may be generated as the recognition value of the reference pattern shows a large difference for each lighting apparatus. The problem can be prevented in advance.

According to the lighting adjustment method of the wire bonder according to the present invention as described above, regardless of the deviation of the components provided in the lighting devices of the wire bonders, when the same parameter input value is input to the lighting devices of each wire bonder, The light sources included in the respective lighting devices can emit light with the same brightness. Therefore, according to the present invention, since the light sources provided in the respective lighting devices, that is, the LEDs emit light with the same brightness irrespective of the deviation of the components provided therein, the reflected light of the light irradiated from the LED to the material side is detected. Cameras in each lighting apparatus that recognizes the reference pattern formed in the apparatus can recognize the reference pattern with the same brightness, that is, the same reference, and may be generated as the recognition value of the reference pattern shows a large difference for each lighting apparatus. There is an effect that can prevent the conventional problem in advance.

Claims (5)

Setting a brightness reference value of a light source shined on the material; And Adjusting an amount of current supplied to the light source based on the reference value; Setting the brightness reference value Inputting a fine current into the light source; Reading the light of the light source emitted by the input current value by an analog to digital converter (ADC) in a camera to determine whether the ADC is the maximum value that can be read by the ADC; If the maximum value that the ADC can read, storing the current value input to the light source and the converted value of the ADC relative to the input current value in the equipment; Dividing a conversion value of the ADC into a plurality of steps based on the memory value; And And setting a reference value for each divided step. delete The method of claim 1, Setting the brightness reference value If the ADC is not the maximum value that can be read, further comprising the step of increasing the amount of current input to the light source so that the ADC reads again to determine whether the ADC is the maximum value that can be read again. How to adjust the lighting of Bonder. The method of claim 3, Adjusting the amount of current Inputting a parameter in each of the divided steps; Determining whether the converted value of the ADC by the input parameter is within a tolerance range of the reference value of the step; And And storing an input parameter that satisfies each step reference value if the converted value of the ADC is within an allowable range of the reference value of the step. 5. The method of claim 4, Adjusting the amount of current If the converted value of the ADC is not within the allowable range of the reference value of the step, further increasing the input parameter to again determine whether the converted value of the ADC is within the allowable range of the reference value of the step Lighting adjustment method of the wire bonder characterized by the above-mentioned.

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