KR100691509B1 - Device and method for measuring view angle of wafer level led - Google Patents

Abstract

A method for measuring the view angle of a wafer-level LED is provided to measure a packaged wafer-level LED or wafer-level LED in which an LED is attached to a wafer by aligning a wafer-level LED with a photodiode and by applying power to the LED. A wafer(30) is positioned on a chuck(40) installed in a prober. The chuck is aligned with the rotation chuck of an arm(10). A probe pin(20) comes in contact with a wafer-level LED(31) and power is applied to the probe pin so that the wafer-level LED or a packaged wafer-level LED emits light. The arm is rotated by the rotation of a motor(50), and the view angle of the wafer-level LED or the packaged wafer-level LED is measured by a photodiode(11) attached to the arm.

Description

Device and method for measuring view angle of wafer level LED

1 is a basic configuration diagram of an apparatus according to the present invention

2 is a conceptual diagram of photometric measurement of a light emitting device using a photodiode according to the present invention.

3 is a light distribution diagram of a light emitting device according to the present invention;

4 is a packaged light emitting device according to the present invention

5 is a photometric measurement of the light emitting device at the wafer level according to the present invention

6 is a front view of the light-emitting device photometric measurement of the wafer level according to the present invention

* Description of the symbols for the main parts of the drawings *

10: cancer

11: photodiode

20: probe

21: probe holder

30: wafer

31: light emitting element

31a: epoxy molding

31b: wire bonding

31c: light emitting element lead

32: position mark

40: Chuck

41: adsorption hole

50: motor

60: light intensity measurement result

61: maximum luminous intensity of light emitting device

62: light emitting device luminous intensity 50% line

62a, 62b: 50% line luminance value and center line connection

The present invention relates to a method and a device for measuring a viewing angle of a light emitting device at a wafer level, and more particularly, to a light emitting device having a light emitting device that is not yet separated from a wafer by measuring light distribution characteristics of the light emitting device. If this is not the case, it is designed to allow selection at the wafer level.

Light emitting diodes (LEDs), which are currently used in various fields, generate light emission by applying power to a semiconductor. This light emission phenomenon is called electric field emission. It must be present in the near-infrared region, have high luminous efficiency, and satisfy the condition that joining can be made by connecting a plurality of light emitting devices, and is mainly gallium arsenide GaAs, gallium phosphide GaP, and gallium arsenide-GaAs1- 2B, 6B or 4A, 4B group semiconductors of 3B and 5B groups, such as x Px, gallium-aluminum-arsenic Ga1-xAlxAs, indium phosphide InP, and indium-gallium phosphorus ln1-xGaxP, are used. Attempts are being made to use.

However, the light emitting devices produced through the fine process always have the possibility of changing the product quality, that is, the light emitting ability of the light emitting devices due to the minute process differences, so it is essential that the light emitting devices have the light emitting ability, in particular, the orientation angle according to the light emission. The quality should be maintained uniformly.

Therefore, the conventional method used for this purpose is to cut the light emitting devices, not the wafer-level light emitting devices, from the wafer into individual chips, attach them to TO cans with leads, and wire-bond the electrodes to be connected to a power source. In the production stage, the device is tested for the electrical characteristics and the light emitting ability of the light emitting device.

Therefore, the conventional method used for this purpose is the electrical characteristics of the light emitting device in the step of producing a packaged light emitting device which is configured to be connected to the power supply by attaching a plastic molding to the light emitting device rather than the wafer level light emitting device And light emitting ability.

However, this method requires the quality inspection of the product through a separate process, so the time required for quality inspection is excessive, and unnecessary waste in the time and cost for the installation of light emitting devices whose quality is not confirmed in the TO can. The problem has been raised as a fundamental cause of the problem.

Accordingly, the present invention proposes a method and an apparatus for measuring the orientation angle of a light emitting device at a wafer level in a dicing state before the light emitting device is attached to a wafer and the light emitting devices are separated.

An object of the present invention is to measure the orientation angle of a light emitting device at the wafer level, and more specifically, to align the wafer-level light emitting device and the photodiode and apply power to the light emitting device to determine the orientation angle of the light emitting device at the wafer level. It was designed to measure.

In order to achieve the above object, in order to measure the orientation angle of the light emitting device packaged at the wafer level or the wafer level attached to the wafer, the wafer is aligned and installed on the chuck 40 installed in the prober And aligning the chuck with the rotational center of the arm, and connecting the probe 20 to the wafer level light emitting device and applying power to the probe to the wafer 30 level light emitting device 31 or wafer level. The packaged light emitting device emits light and the wafer-level light emitting device 31 is rotated by the photodiode 11 attached to the arm 10 by rotating the arm 10 by the rotation of the motor 50. Or measuring the orientation angle [theta] of the packaged light emitting device at the wafer level, and comprises a device capable of achieving the method.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

1 is a basic configuration of an apparatus according to the present invention, the arm 10 is attached to the end of the arm 10 is attached to the sensor (photodiode) (11) which can measure the light intensity of the light emitting element (31) Is configured to rotate by a motor, and the wafer 30 is installed on the chuck 40 installed on the prober, and the height of the wafer 30 installed on the chuck 40 is the center of rotation of the arm 10. In other words, since it is installed at the same height as the rotation center of the motor 50 for rotating the arm, it is configured so that there is no error in measuring the light intensity of the light emitting element 31 according to the rotation of the arm.

In addition, the chuck 40 has a suction hole 41. When the suction hole 41 is in a vacuum state, the wafer 30 is attached to the chuck 40 and is positioned in a fixed state without being moved. Two inspection needles 20 are installed in the bur, and the role of the inspection needle 20 serves to apply power to the light emitting device 31. When the power is applied to the light emitting device 31, light is emitted. When the device 31 emits light, the light emitting characteristics of the light emitting device 31 emitting light are measured using the photodiode 11.

FIG. 2 is a view illustrating a process of obtaining a directivity angle from the measured result by measuring the luminous intensity of the light emitting device 31 while the photodiode 11 installed in the arm rotates as the light emitting device 31 emits light. It is configured to select and adjust the maximum rotation angle and the like of the photodiode 11 attached to the arm 10, and stores the intensity of the light emission of the light emitting element 31 measured by the photodiode 11 as a data The user can determine the suitability of the light emitting device 31 through data analysis. The thickness of the arrow refers to the brightness of the light emitting device 31 generated when power is applied to the light emitting device 31.

3 shows the light distribution measurement result 60 of the light emitting device 31. The 100% line 61 shows the light intensity of the light emitting device 31 by using the photodiode 11 attached to the arm 10. FIG. The profile is formed around the maximum value (Imax: Intensity Max, 61) when measured while rotating, and the 50% line 62 forms the profile around an area corresponding to half the maximum value (Imax). In this case, 50% is used as a standard for the international measurement method, and the angle formed by the 50% line 62 of the light distribution and the two straight lines 62a and 62b connecting the center of the axis is called the direction angle θ. The standard related to this angle of view is defined in the International Standard.

4 is a diagram representing a packaged light emitting device, the light emitting device is wrapped in an epoxy molding 31a, and the light emitting device has a wire bonding 31b to serve to apply power. The packaged light emitting device has a lead 31c attached thereto to serve to supply external power to the light emitting device.

5 shows a wafer to which a light emitting device is attached. Although there are differences depending on the size of the wafer, about 15,000 light emitting devices 31 are formed in one wafer 30, and the wafer 30 is a complete circle. A portion of the wafer may be straightened to form a reference element that is used to set the direction of the wafer or other installation conditions. In addition, the position mark 32 may be formed on the wafer 30 to form the position mark 32. By using the wafer 30 is installed in the chuck 40 and serves as a reference for finding the absolute coordinate of the wafer 30 through the movement of the chuck, the orientation angle of the light emitting element 31 of the wafer 30 level is adjusted. The person who wants to measure serves as a reference point for finding the desired position of the light emitting device 31.

In addition, although the number of light emitting elements formed on the wafer varies depending on the size of the wafer, when about 15,000 light emitting elements are formed, not all 15,000 orientation angles are measured. Since the optical characteristics are generally similar to the electrical and optical characteristics of nearby light emitting devices, when measuring the characteristics of about nine light emitting devices 31 on one wafer, the overall wafer level light emitting devices have about nine light emitting devices. Even if it judges that the light emitting element 31 is large, there is no big crowd.

FIG. 6 shows that the wafer 30 is vacuum-adsorbed and fixed on the chuck 40 which can move in a front view, and when power is applied to the light emitting element 31 at the wafer level by the inspection needle 20, the light emitting element emits light. In this case, the arm 10 is rotated by the motor 50 and the photodiode 11 attached to the arm measures the light intensity of the light emitting device.

Looking at the overall configuration and operation of the device can be described as follows, first, the probe 10 is equipped with an arm 10 is attached to the photodiode 11, which is operated by the motor 50, the correct coordinates at the bottom A chuck 40 capable of moving up, down, left, and right according to the value and having a suction hole 41 configured to vacuum-suck the wafer 30 to be fixed is installed, and a position mark for setting a coordinate value on the wafer 30 is provided. (32) serves as a reference to align the wafer by the absolute coordinate value, and two inspection needles 20 for emitting light by applying power to the light emitting element 31 at the wafer level Will be installed.

Looking at these operating structures, the wafer is first installed in the chuck 40, the wafer is vacuum-adsorbed by the adsorption hole 41 is fixed, and the position mark 32 configured on the wafer as a reference point to the reference coordinate value The positions of the light emitting elements are aligned so that the photodiodes 11 and the light emitting elements formed on the wafer are aligned in a straight line, the position of the wafer surface and the center of the drive shaft of the motor are aligned, and power is applied by the inspection needle to emit light. When the device emits light, the arm 10 is rotated by the motor 50. At this time, the photodiode 11 attached to the arm measures the light intensity of the light emitting device and the measured light intensity value according to the angle of the arm. It will be made of a process of calculating the orientation angle using them.

Here, the position mark of the wafer does not include a light emitting element, and the alignment of the wafer and the photodiode may be performed through a microscope installed on the prober visually or automatically, and the amount of rotation of the motor, that is, the angle of rotation is set by the operator. And the result measured by the photodiode is processed by the software.

In addition, in order to measure the light emission characteristics of the light emitting device when the light emitting device is not separated from the wafer, there should be no obstacle to rotation of the arm. The biggest obstacle is the elements related to the test needle holder with the test needle installed. Because the microscope can be a barrier, the needle should be placed in a location that does not interfere with the operation of the arm and the photodiode should be positioned between the chuck and the microscope.

As described above, when measuring the light emission characteristics of the first light emitting device at the wafer level, it should be moved to the next step. First, when the orientation angle measurement of the light emitting device is completed by the rotation of the arm, the chuck is lowered to the bottom by a certain distance. The chuck is moved to the position of the light emitting device to measure the directivity angle, and the coordinate axis is aligned so that the photodiode and the light emitting device at the wafer level are in a straight line, and the chuck moves to the top so that the center of rotation of the motor and the surface of the wafer are straight. Through the process of being placed on the, it is possible to apply power to the light emitting device by the inspection needle, and when the power is applied and the light emitting device emits light, the process of measuring the direct angle of the light emitting device through the rotation of the arm repeatedly It is going to proceed.

The light distribution characteristics of the light emitting device measured as described above may be expressed as shown in FIG. 3, and the reference angle measuring standard is measured according to the intensity of light generated when the light emitting device emits light as shown in FIG. 2. At this time, the light emitted by the light emitting device is emitted as it is spread all over the top of the wafer, not in one direction. If the center of the light emitting device and the photodiode are in a line up and down, the same result can be obtained in any direction. have.

At this time, the rotation angle of the arm is determined by the user, instead of measuring the part indicating the luminance having a luminance above a certain intensity while rotating starting from the luminance having a luminance above a certain intensity. For example, if the arm is selected from -70 to 70 degrees, Rotates according to this selected angle, and the brightness is measured, and the measurement result is processed in software to calculate the orientation angle.

However, as shown in FIG. 2, the luminous intensity at the center of the light emitting device does not always show the highest value (Imax, 61), and may vary depending on various conditions that are artificial or coincidental in the production process of the light emitting device. The point at zero degrees above and below the coordinate axis and the highest value (Imax, 61) with the highest luminous intensity may not always coincide.

In addition, in the method of obtaining the directivity angle, the photodiode is first measured by the rotation of the arm of the luminous intensity of the light emitting element, and the measurement criteria are the highest point (Imax) from the point where the luminous intensity is 50% of the highest value (Imax, 61). , 61) and the distance to the point 50% of the maximum value of the opposite side is calculated by the software, the calculation is made by the gear ratio of the gear of the motor and the arm for rotating the arm, the brightness of the light emitting element The angle of rotation of the arm from the point of 50% of the maximum to the point of the opposite 50% is calculated.

In addition, a technology for packaging light emitting devices in a wafer state has been developed. This state may also be viewed as the same structure as a light emitting device at a wafer level, and the same method may be used whether or not the light emitting devices are packaged at the wafer level. Through this, the orientation angle can be measured.

Overall, the present invention provides a method and apparatus for measuring a directivity angle of a wafer-level light emitting device, and in order to measure a directivity angle of a wafer-level light emitting device attached to a wafer or a packaged light emitting device at a wafer level, Arranging and installing the wafer in the chuck 40 installed in the burr, aligning the chuck with the rotational center of the arm, connecting the probe 20 to a light emitting element at the wafer level, and applying power to the probe. Allowing the light emitting device 31 at the wafer 30 level or the light emitting device packaged at the wafer level to emit light, and the arm 10 is rotated by the rotation of the motor 50 and attached to the arm 10. Measuring the orientation angle θ of the light emitting element 31 at the wafer level or the packaged light emitting element at the wafer level by means of the photodiode 11. It consists of a device that can.

The present invention has the effect of measuring the orientation angle of the light emitting device at the wafer level as presented in the object of the present invention according to the above configuration.

What has been described above is only one embodiment according to the present invention, and the present invention is not limited to the above-described embodiments, and the present invention belongs without departing from the gist of the present invention as claimed in the following claims. Anyone skilled in the art will have the technical spirit of the present invention to the extent that various modifications can be made.

Claims (3)

A method for measuring the directivity angle of a light emitting element; For measuring a directing angle of a light emitting device at the wafer level or a light emitting device packaged at the wafer level in which the light emitting device is attached to the wafer; Arranging and installing the wafer on the chuck installed in the prober; Aligning the chuck with the center of rotation of the arm; Connecting the probe to a wafer level light emitting device and applying power to the probe to emit light from the wafer level light emitting device or a packaged light emitting device at the wafer level; Measuring the directivity of the wafer-level light emitting device or the packaged light emitting device at the wafer level by means of a photodiode attached to the arm by the rotation of the motor. Device orientation angle measurement method. The method of claim 1, wherein the measuring method of the orientation angle of the light emitting device; Measuring the brightness of the light emitting device by a photodiode attached to a rotating arm; Measuring a moving distance from a point where the brightness of the light emitting device is in the range of 50% of the highest value to a point 50% of the highest value on the opposite side past the highest point; Wafer level light emitting element orientation angle measuring method comprising the step of calculating the rotation angle of the arm by the gear ratio of the motor (the ratio of the gear of the arm to the motor gear) meshed with the gear of the arm for the rotation of the arm. An apparatus for measuring a directing angle of a light emitting element; An arm rotated by a motor attached to the prober; A photodiode measuring a brightness of a light emitting device attached to an end of the arm; An inspection needle holder and an inspection needle installed to avoid interference between the rotating arm and the arm to perform a function of applying power to the light emitting device; At the bottom of the prober, a wafer-level light emitting device is installed, which includes a chuck for performing a function of vacuum suction and fixation and a function of moving a wafer to a predetermined coordinate point in up, down, left and right. Light emitting element directivity angle measuring device.

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