JP2007019237A - Probing device for double-sided light emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a probing device efficiently measuring a double-sided light emitting element. <P>SOLUTION: The probing device for a double-sided light emitting inspects the light emitting element which emits light from both front and rear faces. The probing device includes: a stage 45 for holding the front or rear face of the light emitting element; and a head 3 provided above the stage and having a probe 31 coming into contact with a terminal of the element. The head includes upper light detection means 33 and 35 for measuring light emitting characteristics of the light emitting element. The stage 45 is transparent, and includes lower light detection means 52 and 54 provided under the stage for measuring the light emitting characteristics of the element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a probing apparatus for inspecting light characteristics of a light emitting element by causing a probe to contact a terminal of the light emitting element and inspecting light characteristics of the light emitting element, and in particular, inspecting light characteristics by capturing light emitted from both the front and back surfaces of the light emitting element. The present invention relates to a probing device.

  The semiconductor manufacturing process has a large number of processes, and various inspections are performed in various manufacturing processes in order to guarantee quality and improve yield. For example, when a plurality of chips of a semiconductor device are formed on a semiconductor wafer, electrodes of the semiconductor device of each chip are connected to a tester, a power supply and a test signal are supplied from the tester, and a signal output from the semiconductor device is A wafer level inspection is performed to electrically inspect whether it operates normally. An apparatus for performing wafer level inspection is described in Patent Documents 1 and 2, for example.

  After wafer level inspection, the wafer is affixed to the frame and cut into individual chips with a dicer. For each chip that has been cut, only chips that have been confirmed to operate normally are packaged in the next assembly process, and defective chips are excluded from the assembly process. Further, the packaged final product is subjected to shipping inspection.

  Light emitting elements such as LEDs are also formed on a wafer, and then a wafer level inspection is performed to assemble only non-defective products. The light emitting element measures a light emission amount and a light emission wavelength when a predetermined voltage is applied to a terminal, and the light emission amount is determined to be a good product when the light emission wavelength is within a predetermined range.

  FIG. 1 is a projected view showing a schematic configuration of a conventional probing apparatus that performs wafer level inspection of a light emitting element, a side view showing a part of the head in cross section, a top view showing a stage, and each element of the head The position is indicated by a broken line.

  In FIG. 1, reference numeral 1 denotes a moving table provided in a moving mechanism capable of XYZ triaxial movement and rotation. A stage mechanism 2 for holding the wafer is provided on the movable table 1. The stage mechanism 2 has a housing composed of a bottom plate 20 provided on the movable table 1, a side plate 21, and a stage 22 having a mounting surface on which the wafer 10 is held on the upper surface. A vacuum path 23 for vacuum-sucking the wafer 10 is provided below the stage 22 mounting surface, and the vacuum path 23 is connected to a vacuum source via a connection port 24 provided on the side surface. By reducing the air pressure in the vacuum path 23, the wafer 10 placed on the placement surface of the stage 22 is vacuum-sucked and fixed to the stage 22. In order to move the wafer 10 onto and from the mounting surface of the stage 22, three pins 26 are provided so as to be vertically movable from the holes 25 on the mounting surface of the stage 22. . The three pins 26 are moved up and down by a motor drive or pneumatic drive device 27 provided on the bottom plate 20.

  When placing the wafer on the placement surface of the stage 22, the stage mechanism 2 is moved to the wafer delivery position by the moving mechanism, and the wafer held by the transfer arm is placed on the three pins 26 raised. To do. Next, the three pins 26 are lowered to place the wafer on the placement surface of the stage 22 and vacuum-suck it. When the wafer is transported from the stage 22 mounting surface, the stage mechanism 2 is moved to the wafer delivery position, the three pins 26 are raised with the vacuum suction released, and the transport arm is moved below the wafer. Then, the wafer is raised and placed on the transfer arm and held. Since the structure of the above stage mechanism is widely known, detailed description is omitted.

  On the other hand, the head 3 is disposed above the stage mechanism 2. Therefore, the stage mechanism 2 can move relative to the head 3. Although an example in which a moving mechanism for moving the stage mechanism 2 is provided is described here, the head 3 can also be moved.

  The head 3 includes a head housing 30, a probe card 32 attached to the head housing 30, a light amount detector (optical power meter) 33 for detecting a light emission amount of the light emitting element, and a light output from the light emitting element. And a wavelength measuring fiber 35 for guiding light to a spectrometer for detecting the wavelength. The light quantity detector 33 is attached to the housing 30 by an attachment mechanism 34 so that the attachment position can be adjusted in three axial directions. The wavelength measuring fiber 35 is attached to the housing 30 by an attachment mechanism 36 so that the attachment position can be adjusted in three axial directions.

  The probe card 32 is provided with a stylus (probe) 31 that contacts a terminal of a light emitting element on the wafer 10. The position of the stylus 31 is measured in advance by a needle position camera.

  When performing the measurement, the wafer 10 is fixed to the stage 22, the position of the terminal is detected by the alignment camera, the stage 22 is moved so that the stylus 31 is located immediately above the terminal, and then the stage 22 is raised. The stylus 31 is brought into contact with the terminal. A current is supplied to the stylus 31 to cause the light emitting element to emit light, and the light emission amount and wavelength are measured. Since a plurality of light emitting elements are formed on the wafer 10, measurement is performed by sequentially moving the stylus 31 so as to contact the terminals of the respective light emitting elements. Note that not only the light characteristics of the light-emitting element but also the electrical characteristics are measured.

Japanese Patent Laid-Open No. 10-150081 JP 2002-170855 A

  The terminal of the light emitting element is provided on the front or back surface of the wafer, but what can be measured by the conventional probing apparatus of FIG. 1 is the light characteristic on the front side of the light emitting element provided with the terminal on the front surface. Characteristics cannot be measured. In addition, the optical characteristics on the front surface side of a light emitting element having a terminal on the back surface cannot be measured.

  In recent years, light-emitting elements have been used not only for light emitted from the front surface side but also for light emitted from the back surface side. In wafer level inspection, light emitted from both surfaces is used. Need to be inspected. However, in the conventional probing apparatus as shown in FIG. 1, a terminal is formed on the surface of the wafer, and only the light emitted from the wafer surface can be detected, and the light emitted from the back surface of the wafer can be detected. I can't. Therefore, in order to detect light emitted from the back surface of the wafer, the wafer is inverted and placed on the stage for measurement. However, it is necessary to invert the wafer and perform measurement twice. There was a problem of low throughput.

  The present invention solves such a problem, and an object of the present invention is to realize a probing apparatus that can efficiently measure a light emitting element that needs to inspect light emitted from both sides of a wafer.

  In order to achieve the above object, the probing apparatus of the present invention not only provides the light detection means on the head, but also provides the light detection means on the stage side with the stage made transparent.

  That is, the probing device of the present invention is a double-sided light-emitting element probing device that inspects light-emitting elements that emit light from both the front and back surfaces, a stage that holds the front or back surface of the light-emitting element, A head having a probe disposed on the upper side and in contact with a terminal of the light emitting element, the head further comprising upper light detecting means for measuring light emission characteristics of the light emitting element, the stage being transparent, and the stage And a lower light detection means for measuring the light emission characteristics of the light emitting element.

  According to the present invention, when the terminals are provided on the front surface of the wafer, the wafer is held with the front surface facing up, and when the terminals are provided on the back surface of the wafer, the wafer is held with the back surface facing up. Measure. As a result, it is possible to measure the optical characteristics of both the front and back sides of a light-emitting element with a terminal provided on the front or back side, and to measure the light emitted from both sides at the same time. Is expensive.

  The wafer needs to be fixed on the stage, and the stage is provided with a suction means for sucking the front or back surface of the wafer. When the suction means is a vacuum suction mechanism, a vacuum path is provided in a transparent stage. The vacuum path is a cavity provided in a transparent stage and does not affect the detection by the lower light detection means so much, but in order to reduce the influence, it may be arranged to adsorb the periphery of the wafer. desirable.

  Also, in order to carry the wafer onto the stage and to carry it out of the stage, as in the prior art, there are three pins for moving the wafer upward from the stage surface and a pin moving mechanism for moving the three pins. It is desirable to provide a hole through which three pins pass through the stage. The three pins are arranged to support the peripheral part of the wafer, and the three pins are made flexible so that the lateral movement can be changed to the vertical movement. It is desirable to be able to arrange at a position that does not affect the detection by the lower light detection means.

  The upper light detection means and the lower light detection means each include a light amount detector and a light wavelength detector so that the light emission amount and the light emission wavelength can be measured.

The transparent stage can be made of, for example, glass or a transparent resin, and it is desirable to use a plate made of quartz glass or resin having a high light transmittance over a wide wavelength.
The probing apparatus of the present invention is preferably realized by using the conventional probing apparatus as shown in FIG. 1 as it is. For example, the stage mechanism 2 attached to the moving table 1 is emitted to the lower side of the present invention. It is desirable that this can be realized by exchanging with a stage mechanism for measuring the light to be measured.

  In this example, measurement is performed by placing the wafer on the stage, but probing each chip of the uncut, half-cut, or full-cut wafer attached to the dicing frame with dicing tape. If the probing apparatus of the present invention is also a transparent dicing tape, it is possible to measure an uncut, half-cut, or full-cut wafer attached to the dicing frame with a dicing tape. The characteristics of light emitted on both sides of each chip can be measured.

  According to the present invention, it is possible to measure both the front side and back side light characteristics of the light emitting element provided with the terminal on the front side or back side, and simultaneously measure the light emitted from both sides, so that the measurement throughput can be measured. Will improve.

  FIG. 2 is a projection view showing a schematic configuration of the probing apparatus according to the embodiment of the present invention, and corresponds to FIG. As shown in the figure, in the probing apparatus of the embodiment, the head 3 has the same configuration as the conventional example of FIG. 1, and only the stage mechanism 40 mounted on the movable table 1 is different. In other words, the probing apparatus of the embodiment can be realized by attaching the stage mechanism 40 of the present embodiment instead of the stage mechanism 2 of the conventional example.

  The stage mechanism 40 has a housing composed of a bottom plate 41, a side plate 42, and an upper plate 43 provided on the movable table 1. A stage plate 45 made of glass or transparent resin is fixed to the stage frame 44, and the stage frame 44 is attached to the upper plate 43. It is also possible to attach the stage plate 45 directly to the upper plate 43 without providing the stage frame 44. In this embodiment, the stage plate 45 is made of resin, but it is also possible to make a policy with quartz glass or the like.

  A vacuum path 46 for vacuum-sucking the wafer 10 is provided under the mounting surface of the stage plate 45, and the vacuum path 46 is connected to a vacuum path provided in the stage frame 44 and the upper plate 43. It is connected to a vacuum source via a connection port 47 provided on the side surface of the upper plate 43. Although not shown, an elastic connection member or the like is used for a connection portion of the stage plate 45 and the stage frame 44 and the stage frame 44 and the upper plate 43 of the vacuum path 46. As shown in the figure, the vacuum path 46 is provided with an opening so as to suck the peripheral portion of the wafer 10 placed on the stage plate 45, and no opening is provided at the center of the wafer 10.

  The mounting surface of the stage plate 45 is provided with three holes 48 through which the three pins 49 pass. The three pins 49 are moved by a pin drive mechanism 51 provided on the side plate 42 via the pin guide mechanism 50. The three pins 49 are flexible, and when moved in the horizontal direction by the pin guide mechanism 50, the three pins 49 in the three holes 48 move in the vertical direction. Thereby, the pin drive mechanism 51 can be provided at a position that does not affect the light measurement.

  Under the stage plate 45, light is guided to a lower light amount detector (optical power meter) 52 for detecting the light emission amount of the light emitting element and a spectrometer for detecting the wavelength of light output from the light emitting element. And a lower wavelength measuring fiber 54. The lower light amount detector 52 is attached to the bottom plate 41 by an attachment mechanism 53 so that the attachment position can be adjusted in three axial directions. Similarly, the lower wavelength measurement fiber 54 is attached to the bottom plate 41 by an attachment mechanism 55 so that the attachment position can be adjusted in three axial directions. The lower light amount detector 52 and the lower wavelength measurement fiber 54 are the same as those provided in the head 3 and are preferably provided at symmetrical positions with respect to the wafer 10, but are not limited thereto. However, an arrangement capable of performing the required measurement may be realized.

The measurement can be performed in the same manner as a conventional probing apparatus, and is placed on the stage plate 45 with the surface of the wafer 10 provided with the terminal facing up, the probe 31 is brought into contact with the terminal, and the light emitting element emits light. The light emitted to both the upper side and the lower side is measured.
If a transparent dicing tape is used, the probing apparatus of the present invention can measure the optical characteristics of each chip of an uncut, half-cut or full-cut wafer attached to a dicing frame with a dicing tape.

  The present invention is applicable when measuring a wafer on which light emitting elements that emit light from both surfaces are formed.

It is a figure which shows schematic structure of the conventional probing apparatus for light emitting elements. It is a figure which shows schematic structure of the probing apparatus for double-sided light emitting elements of the Example of this invention.

Explanation of symbols

1 moving table 2 stage mechanism 3 head 10 wafer 31 stylus (probe)
33 Light intensity detector (optical power meter)
35 Fiber for wavelength measurement 45 Transparent stage plate 52 Lower light quantity detector (optical power meter)
54 Lower wavelength measurement fiber

Claims (4)

A probing device for a double-sided light emitting device that inspects a light emitting device that emits light from both the front and back surfaces,
A stage for holding the front surface or the back surface of the light emitting element;
A head having a probe disposed on the stage and contacting a terminal of the light emitting element;
The head includes upper light detection means for measuring the light emission characteristics of the light emitting element,
The stage is transparent,
A double-sided light-emitting element probing device, comprising: a lower-side light detection unit that is disposed on the lower side of the stage and measures a light emission characteristic of the light-emitting element. The light emitting element is formed on a wafer, and the terminal of the light emitting element is formed on the front surface or the back surface of the wafer,
The probing apparatus for a double-sided light emitting element according to claim 1, wherein the stage includes a suction unit that sucks a front surface or a back surface of the mounted wafer. Three pins for moving the wafer placed on the stage upward from the surface of the stage, and a pin moving mechanism for moving the three pins,
The stage has a hole through which the three pins pass,
The probing device for a double-sided light emitting element according to claim 1, wherein the three pins are flexible.   The probing apparatus for a double-sided light emitting element according to claim 1, wherein each of the upper light detection means and the lower light detection means includes a light amount detector and an optical wavelength detector.

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