TW201348719A - Wafer-level LED measuring device and measuring method thereof - Google Patents

Abstract

The present invention discloses a wafer-level LED measuring device and a measuring method thereof. The wafer-level LED measuring device includes: a probe test card, a collector and optical sensors. The collector is connected to the top side of the probe test card. It is composed of M integrate rods or M Compound Elliptical Concentrators (CECs). Each integrate rod or each CEC has a light receiving surface and a light emitting surface. One optical sensor is disposed on one light emitting surface. Besides, the integrate rods are made of gradient-index material. With the implementation of the present invention, the wafer-level LED measuring device measures multiple LED chips simultaneously so as to improve the efficiency of screening of the LED dies.

Description

Wafer level LED measuring device and measuring method thereof

The invention relates to a wafer level LED measuring device and a measuring method thereof, in particular to a wafer level LED measuring device capable of simultaneously measuring a plurality of LED dies and a measuring method thereof.

US Patent No. 2011/0267087 discloses a semiconductor test system including a wafer holder for holding a wafer having a plurality of LED dies; and a probe card for detecting each LED of the wafer a die region; and a photodetector for collecting light from the LED die on the wafer to detect optical characteristics of the LED die. This semiconductor test system can test all LED dies one by one along a trajectory, because only one LED die can be tested at a time, so it takes a long test time to complete the test of the LED dies on all wafers.

US Patent No. 2009/0236506 discloses a test system for an on-wafer LED, comprising: a wafer having a plurality of LED dies; a light collecting component for collecting light emitted by the LED dies; A detector coupled to the light collecting component and designed to detect a portion of the scattered light. Such on-wafer LED test systems typically use an integrating sphere as a light collecting component, and a detector coupled to the integrating sphere detects the optical characteristics of the LED die.

The above test system for on-wafer LEDs using an integrating sphere has some problems to be solved. Since the size of the LED dies on the wafer is relatively small and the distribution density is quite high, the optical characteristics of a single LED dies cannot be discriminated when using an integrating sphere. In addition, the test system for the LED on the wafer using the integrating sphere is not particularly The LED die sets the exclusive test specification so that the light will be reflected from the entrance after multiple reflections in the integrating sphere, thus causing test errors. Therefore, there is a need for a measurement system that can more accurately measure the optical characteristics of LED dies on a wafer, and it is expected to have a measurement device capable of simultaneously measuring a plurality of LED dies to save measurement time.

The invention is a wafer level LED measuring device, comprising: a probe card, a light collecting component and a plurality of light sensors. The invention is mainly to achieve optical characteristics of a plurality of LED dies that can be simultaneously measured on a wafer to accelerate the screening of LED dies.

The invention provides a wafer level LED measuring device, comprising: a probe card having a complex array probe; a light collecting component coupled to the upper side of the probe card, and the light collecting component is integrated with M points The column is composed of a column and each of the integrating columns has a light receiving surface and a light emitting surface, and the integrating column is made of a graded material; and a plurality of light sensors, each of which is disposed on a light emitting surface.

The invention further provides a wafer level LED measuring device, comprising: a probe card having a complex array probe; a light collecting component coupled to the upper side of the probe card, and the light collecting component is M composite The ellipsoidal concentrator is configured and each composite ellipsoid concentrator has a light receiving surface and a light emitting surface; and a plurality of light sensors, each of which is disposed on a light emitting surface.

The invention further provides a method for measuring a wafer level LED measuring device, comprising the steps of: providing a wafer, and planning a plurality of measured regions on the wafer, wherein each of the tested regions has a plurality of LEDs Grain; providing a measuring device, which is a a wafer level LED measuring device, the measuring device having a plurality of integrating columns or a plurality of composite ellipsoid concentrators; performing alignment, wherein at least one integrating column or at least one composite ellipsoid concentrator center corresponds to one receiving One of the LED dies in the measurement area; electrical contact, which lowers the measuring device to the optimal measuring distance h, and contacts the pins of a probe card to the electrodes of the LED dies; optical characteristic measurement, The optical measurement of the LED dies by the measuring device to obtain a plurality of optical measurement information; the analysis of the records, the analysis of the optical measurement information to generate a plurality of first marking information and Recording; and marking the inferior product, which infers the LED dies according to the first mark information.

With the implementation of the present invention, at least the following advancements can be achieved:

First, multiple LED dies can be measured on the wafer at the same time to improve the efficiency of measurement.

Second, the accuracy of measurement can be improved.

Third, the optical and electrical properties of the LED die can be measured simultaneously.

In order to make those skilled in the art understand the technical content of the present invention and implement it, and according to the disclosure, the patent scope and the drawings, the related objects and advantages of the present invention can be easily understood by those skilled in the art. The detailed features and advantages of the present invention will be described in detail in the embodiments.

[An embodiment of a wafer level LED measuring device]

1 is a cross-sectional view of a wafer level LED measuring device according to an embodiment of the present invention. 2 is a perspective view of a wafer level LED measuring device according to an embodiment of the present invention; Figure. Figure 3 is a schematic view of the probe contacting the LED die according to an embodiment of the present invention. 4A is a perspective view of a cylindrical integrator column according to an embodiment of the present invention. FIG. 4B is a perspective view of a square column type integral column according to an embodiment of the present invention. FIG. 5 is a schematic diagram of a ray travel trajectory of a refractive index grading material according to an embodiment of the present invention. FIG. 6A is a schematic diagram of a trajectory of light rays in a 1/2 pitch cylindrical integrator column according to an embodiment of the present invention. FIG. 6B is a schematic diagram of a trajectory of light rays in a 1/2 pitch square column type integral column according to an embodiment of the present invention. FIG. 7A is a schematic diagram of a trajectory of light rays in a 1/4 pitch cylindrical integral column according to an embodiment of the present invention. FIG. 7B is a schematic diagram of a ray travel path in a 1/4 pitch square column type integral column according to an embodiment of the present invention. Figure 8 is a perspective view of another wafer level LED measuring device according to an embodiment of the present invention. Figure 9 is a perspective view of a composite ellipsoid concentrator in accordance with an embodiment of the present invention. Figure 10 is a schematic diagram of the trajectory of light rays in a composite ellipsoid concentrator.

As shown in FIGS. 1 and 2, a wafer level LED measuring device 100 according to an embodiment of the present invention can be used to simultaneously measure optical and electrical characteristics of a plurality of LED dies 210. The wafer level LED measuring device 100 includes a probe card 110, a light collecting component 120, and a plurality of photo sensors 130.

Please also refer to FIG. 3, the probe card 110 has a complex array of probes 111 for directly contacting the electrodes 211 and 212 of the LED die 210 to form an electrical connection, and the electrodes 211 and 212 are pads. Or a bump is formed, and when the probe 111 is electrically connected to the LED die 210, the probe 111 can conduct the LED die 210 and measure the electrical characteristics of the LED die 210, such as a VI electrical curve, etc., and Data from this electrical characteristic is passed to computer analysis. The measured LED die 210 is typically about 7*9 mil ^{2 in} size, the source type is a Lambertian source, the illuminating half angle is between 50° and 65°, and the source band is set to 0.486, 0.587 or 0.656 microns.

The light collecting component 120 is coupled to the upper side of the probe card 110 and electrically connected to the probe card 110. The probe 111 of the probe card 110 has a certain height plus the distance of the light collecting component 120 from the LED die 210. When it is too large, the light emitted by the LED die 210 will overflow the light collecting element 120 and cannot be completely detected. The preferred distance between the light collecting element 120 and the LED die 210 can be determined by the divergence angle (FWHM) of the LED die 210 and the size of the light incident surface of the light collecting element 120. In general, the minimum value of h is determined by the space in which the probe 111 is placed, and the maximum value of h is inversely proportional to the divergence angle (FWHM) of the LED die 210. Under the size of the fixed light collecting element 120, the FWHM is large. The LED die 210 has a smaller range of adjustable h. A better measurement effect can be obtained when h is about 0.3 to 0.5 mm.

In addition, the light source emitted by the LED die 210 can be focused by the light collecting element 120 to measure optical characteristics of the LED die 210, such as luminous flux and the like. The light collecting element 120 is composed of M integrating columns 121 and each of the integrating columns 121 has a light receiving surface 122 and a light emitting surface 123. The light source emitted from the LED die 210 enters the integrating column 121 via the light receiving surface 122, and then exits the integrating column 121 by the light emitting surface 123.

As shown in FIGS. 4A and 4B, the integrating column 121 may be a cylindrical integrating column or a cylindrical integrated column, and may have a length of 2.5 mm to 20 mm and a diameter or a side length of 0.5 mm to 5 mm. In addition, the material of the integrating column 121 may be differently selected according to different use requirements. In the embodiment of the present invention, a gradient material (GRIN material) having a gradient index (GRadient-INdex) property is used, and the refractive index of the graded material is The wavelength of light and the position of travel Constantly changing. The refractive index center may have a refractive index of 1.5 to 1.65, and the graded material may be glass.

As shown in Figure 5, when light enters the grading material (such as the fiber in the field of optical communication), the light is repeatedly focused within the grading material, so that the trajectory will take the form of a sine wave. The optical path of a cycle is often referred to as a pitch. In order to maximize the effect of light focusing, the integrating column 121 used may be a 1/2 pitch integrating column or a 1/4 pitch integrating column.

As shown in Fig. 6A and Fig. 6B, a 1/2 pitch cylindrical integral column or a 1/2 pitch square column type integral column can be used, and the light passes through a 1/2 pitch cylindrical integral column or 1 The square column type integrating column of /2 pitch can be focused on the light emitting surface 123, wherein the integrating column 121 can be made using SELFOC's SLW200.

As shown in Figures 7A and 7B, a 1/4 pitch cylindrical integral column or a 1/4 pitch square column type integral column can also be used to form a collimated spot on the light exit surface 123. Wherein the integral column 121 can be made using SELFOC's SLW200. The 1/4 pitch cylindrical integral column has extremely high light transmission efficiency, and with anti-reflective coating treatment, the optical transmission efficiency can be as high as 99%.

As shown in FIG. 1 , the photo sensor 130 is disposed on the light emitting surface 123 of the integrating column 121 and is the same as the diameter or the side length of the integrating column 121 to sense the light on the light emitting surface 123 for Detecting optical characteristics such as luminous flux, spectrum, color coordinates and color rendering (CRI), and transmitting the generated optical signals to computer analysis. By computer analyzing whether the optical and electrical characteristics of the LED die 210 reach a preset standard, Different quality LED dies 210 are screened and the defective products are marked.

As shown in FIG. 8, a wafer level of another embodiment of this embodiment The LED measuring device 300 forms a light collecting element 320 with M composite ellipsoidal concentrator (CEC) 321 instead of the original embodiment of the light collecting element by M integral columns, and the probe card The 310 is still used to make electrical contact with the LED die 210. After the LED die 210 emits a light source, the composite ellipsometer concentrator 321 collects the light of the LED die 210 into the photo sensor 330, and the photo sensor 330 will detect Optical properties such as photometric flux, spectrum, color coordinates, and color rendering (CRI).

As shown in FIG. 9 and FIG. 10, the composite ellipsoid concentrator 321 is a reflective cup having a composite ellipsoidal surface 322, and the composite ellipsoidal surface 322 is coated with a high reflectivity material, so the light collecting principle is utilized. The bifocal geometry of the composite ellipsoidal surface 322 converges the light emitted by the LED dies 210 into the illuminating surface 323 through the reflection of the composite ellipsoidal surface 322 in the composite ellipsometer concentrator 321 to provide a light sensation behind the illuminating surface 323. The detector 330 is easy to detect.

[A method for measuring the wafer level LED measuring device]

11 is a flow chart of a method for measuring a wafer level LED measuring device according to an embodiment of the present invention. FIG. 12 is a first schematic diagram of a measurement method of a wafer level LED measuring device according to an embodiment of the present invention. FIG. 13 is a second schematic diagram of a measurement method of a wafer level LED measuring device according to an embodiment of the present invention. FIG. 14 is a schematic diagram of a trajectory of light rays in an integrating column when performing a light characteristic measuring step according to an embodiment of the present invention. FIG. 15 is a third schematic diagram of a measurement method of a wafer level LED measuring device according to an embodiment of the present invention.

As shown in FIG. 11 , a method S100 for measuring a wafer level LED measuring device according to an embodiment of the present invention includes the following steps: providing a wafer and a wafer. A plurality of test areas are planned on (step S10); a measuring device is provided (step S20); alignment is performed (step S30); electrical contact (step S40); optical characteristic measurement (step S50); analysis record (Step S60) and marking the inferior product (step S70).

As shown in FIG. 12 and FIG. 13, a wafer is provided, and a plurality of measured regions are planned on the wafer (step S10). The wafer 200 may be a gossip wafer, and each of the tested regions 220 There are a plurality of LED dies 210 therein. For example, in the center of a gossip wafer, nine tested areas 220 are planned, here areas 18, 19, 20, 25, 26, 27, 32, 33 and 34. LED dies 210 on region 18 are designated by codes 11, 12, 13... and LED dies 210 on region 19 are designated by codes 21, 22, 23....

Providing a measuring device (step S20), which is a wafer level LED measuring device 100/300, and when the measuring device is a wafer level LED measuring device 100, it has a plurality of integrating columns 121, or a measuring device When it is a wafer level LED measuring device 300, it has a plurality of composite ellipsoid concentrators 321.

The alignment is performed (step S30), wherein the center of the at least one integrating column 121 or the at least one composite ellipsometer concentrator 321 corresponds to one of the LED dies 210 in the tested area 220. For example, there are a wafer level LED measuring device 100/300 above the nine tested areas 220 of the regions 18, 19, 20, 25, 26, 27, 32, 33 and 34, if the measuring device is a wafer level LED amount When the device 100 is tested, it has nine integrating columns 121, and the centers of the nine integrating columns 121 are located just above one of the LED dies 210 in one of the tested regions 220. If the measuring device is the wafer level LED measuring device 300, it has nine composite ellipsoid concentrators 321 , and the center of the nine composite ellipsoid concentrators 321 is exactly one LED crystal in each of the tested regions 220 Above the pellet 210.

Electrical contact (step S40), which reduces the measuring device 100/300 to the most Preferably, the distance h is measured, and the pins of a probe card are brought into contact with the electrodes of the LED die 210, and the LED die 210 is turned on.

Please also refer to FIG. 14 for optical characteristic measurement (step S50), which is used to measure the LED die 210 by the measuring device 100/300. If the measuring device 100 is used, the integrating column 121 of the grading material is used. The light emitted by the LED die 210 is aligned to the photo sensor 130 to obtain an optical signal, thereby obtaining a plurality of light measurement information. If the measuring device 300 is used, the light emitted by the LED die 210 is reflected by the composite ellipsometer 321 to the photo sensor 330 to obtain an optical signal, thereby obtaining a plurality of light measurement information. While the optical characteristic measurement (step S50) is performed, each LED die 210 can be electrically measured (step S51) to obtain a plurality of electrical energy measurement information.

For example, when performing optical characteristic measurement (step S50) or electrical measurement (step S51), nine integral columns 121 or composite ellipsometer concentrators 321 are simultaneously measured at respective integral columns 121 or composite ellipsoid sets. The LED die 210, coded 11, 21, 31, 41, 51, 61, 71, 81, 91 below the center of the optical device 321 obtains a plurality of light measurement information or power measurement information.

The record is analyzed (step S60), which analyzes the light measurement information to generate a plurality of first mark information and record it. When the LED die 210 is electrically measured (step S51), the analysis record (step S60) may further analyze the power measurement information to generate and record a plurality of second tag information.

The inferior product is marked (step S70), and the LED die 210 is inferiorly marked according to the first mark information. When the LED die 210 is electrically measured (step S51), the marked inferior product (step S70) may also be in accordance with the first mark information or the second The mark information marks the LED die 210 as inferior. If there are no defective LED dies 210, the procedure for marking the defective product (step S70) can be skipped.

Referring again to FIG. 15, after the above steps are completed, if there are still undetected LED dies 210, the wafer level LED measuring device 100/300 is moved for the second measurement. At the second measurement, the center of the nine integrating columns 121 or the composite ellipsometer 321 has moved to the LED die 210 codenamed 12, 22, 32, 42, 52, 62, 72, 82, 92. The nine LED dies 210 are measured at the same time and simultaneously, and the wafer level LED measuring device 100/300 is moved after the measurement is completed for the third measurement. After repeated measurement operations, all LED dies 210 in each of the tested regions 220 can be measured.

The wafer level LED measuring device 100/300 of the embodiment can measure the optical characteristics and electrical characteristics of the plurality of LED dies 210 at the same time, thereby greatly improving the efficiency in the detection process, and the integral used for collecting the light source. The column 121 or the composite ellipsoid concentrator 321 allows the light source to be more completely collected into the photodetector, thereby greatly improving the accuracy of the measurement.

The embodiments are described to illustrate the features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the present invention and to implement the present invention without limiting the scope of the present invention. Equivalent modifications or modifications made by the spirit of the disclosure should still be included in the scope of the claims described below.

100, 300‧‧‧ Wafer-level LED measuring device

110, 310‧‧ ‧ probe card

111‧‧‧Probe

120, 320‧‧‧Light collecting components

121‧‧·Integral column

122‧‧‧Light acceptance surface

123, 323‧‧‧Glossy

130, 330‧‧‧Light sensor

200‧‧‧ wafer

210‧‧‧LED dies

211, 212‧‧‧ electrodes

220‧‧‧Measured area

321‧‧‧Composite ellipsoid collector

322‧‧‧Composite ellipsoid

1 is a cross-sectional view of a wafer level LED measuring device according to an embodiment of the present invention.

2 is a perspective view of a wafer level LED measuring device according to an embodiment of the present invention.

Figure 3 is a schematic view of the probe contacting the LED die according to an embodiment of the present invention.

4A is a perspective view of a cylindrical integrator column according to an embodiment of the present invention.

FIG. 4B is a perspective view of a square column type integral column according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of a ray travel trajectory of a refractive index grading material according to an embodiment of the present invention.

FIG. 6A is a schematic diagram of a trajectory of light rays in a 1/2 pitch cylindrical integrator column according to an embodiment of the present invention.

FIG. 6B is a schematic diagram of a trajectory of light rays in a 1/2 pitch square column type integral column according to an embodiment of the present invention.

FIG. 7A is a schematic diagram of a trajectory of light rays in a 1/4 pitch cylindrical integral column according to an embodiment of the present invention.

FIG. 7B is a schematic diagram of a ray travel path in a 1/4 pitch square column type integral column according to an embodiment of the present invention.

Figure 8 is a perspective view of another wafer level LED measuring device according to an embodiment of the present invention.

Figure 9 is a perspective view of a composite ellipsoid concentrator in accordance with an embodiment of the present invention.

Figure 10 is a schematic diagram of the trajectory of light rays in a composite ellipsoid concentrator.

11 is a flow chart of a method for measuring a wafer level LED measuring device according to an embodiment of the present invention.

FIG. 12 is a first schematic diagram of a measurement method of a wafer level LED measuring device according to an embodiment of the present invention.

FIG. 13 is a second schematic diagram of a measurement method of a wafer level LED measuring device according to an embodiment of the present invention.

FIG. 14 is a schematic diagram of a trajectory of light rays in an integrating column when performing a light characteristic measuring step according to an embodiment of the present invention.

FIG. 15 is a third schematic diagram of a measurement method of a wafer level LED measuring device according to an embodiment of the present invention.

100‧‧‧ Wafer-level LED measuring device

110‧‧‧ probe card

120‧‧‧Light collecting components

121‧‧·Integral column

122‧‧‧Light acceptance surface

123‧‧‧Glossy

130‧‧‧Light sensor

200‧‧‧ wafer

210‧‧‧LED dies

Claims (9)

A wafer level LED measuring device, comprising: a probe card having a complex array probe; a light collecting component coupled to an upper side of the probe card, the light collecting component being M integrated columns Each of the integrating columns has a light receiving surface and a light emitting surface, the integral columns are made of a graded material; and a plurality of light sensors, each of the light sensors being disposed on the light output On the surface. The wafer level LED measuring device according to claim 1, wherein the integrating columns are a 1/2 pitch integrating column or a 1/4 pitch integrating column. The wafer level LED measuring device according to claim 1, wherein the integrating columns are a cylindrical integrating column or a one-column integrating column. The wafer level LED measuring device according to claim 1, wherein the grading material is a glass. A wafer level LED measuring device, comprising: a probe card having a complex array probe; a light collecting component coupled to an upper side of the probe card, the light collecting component being composed of M composite ellipsoids Each of the composite ellipsometer concentrators has a light receiving surface and a light emitting surface; and a plurality of light sensors, each of the light sensors being disposed on the light emitting surface. A method for measuring a wafer level LED measuring device, comprising the steps of: providing a wafer, and designing a plurality of measured regions on the wafer, each of the plurality of LED dies in the tested region Providing a measuring device, which is a wafer level LED measuring device, the amount The measuring device has a plurality of integrating columns or a plurality of composite ellipsoid concentrators; performing alignment, wherein at least one of the integrating columns or at least one of the composite ellipsoid concentrator centers corresponds to one of the tested regions LED die; electrical contact, which is to lower the measuring device to the optimal measuring distance h, and to make the pins of a probe card contact the electrodes of the LED dies; the optical characteristic measurement is performed by The measuring device optically measures the LED dies to obtain a plurality of optical measurement information; and analyzes the records by analyzing the light measurement information to generate a plurality of first mark information and recording the same; And mark the inferior product, which infers the LED dies according to the first mark information. The measuring method according to claim 6, wherein the optical characteristic measuring step can also perform an electrical measurement on each of the LED dies to obtain a plurality of electrical quantity measurement information. The measurement method of claim 7, wherein the analysis recording step further analyzes the electrical energy measurement information to generate and record a plurality of second marker information. The measuring method of claim 8, wherein the marking inferior step is to mark the LED dies according to the first marking information or the second marking information.