JP2014134497A - Apparatus and method for measuring optical characteristic of led chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide apparatus and method for measuring the optical characteristic of an LED chip capable of efficiently measuring the optical characteristic of the LED chip.SOLUTION: An apparatus 10 for measuring the optical characteristic of an LED chip comprises: a transparent table 20 in which a group of flip-chip LEDs 5 which are a plurality of flip-chip LEDs 1 formed by dicing a semiconductor wafer 4 on an adhesive tape 6; a light pipe 30 having a flat incident section 31 which adheres to the lower surface of the transparent table 20, and makes light transmitted through the transparent table 20 incident thereon as incident light, and an emission section 32 which uniformizes the incident section, and emits the uniformized light as emission light; a transmission diffusion member 40 mounted on the emission section 32 side; and a photodetector 50 which detects the emission light. When a probe 7 comes in contact with an electrode 2, the group of flip-chip LEDs 5 is mounted on the transparent table 20 together with the adhesive tape 6.

Description

  The present invention relates to an LED chip optical property measuring apparatus and a LED chip optical property measuring method used for measuring optical characteristics of a light emitting diode (LED) chip.

  Conventionally, as an apparatus for measuring optical characteristics (for example, intensity, wavelength, etc.) of a manufactured LED chip in a semiconductor manufacturing process, an optical characteristic measuring apparatus described in Patent Document 1 has been proposed.

  This optical characteristic measuring apparatus includes a plate on which an LED chip is placed, a probe disposed on the upper surface side of the plate, a light collector disposed on the lower surface side of the plate, an optical fiber attached to the light collector, and optical characteristics. It is comprised from the measurement part which measures. According to this optical characteristic measuring apparatus, the flip chip LED having the electrode formed on the upper surface and the light emitting surface formed on the lower surface is adsorbed to the plate of the condenser. The probe pin contacts the electrode and the flip chip LED emits light. The emitted light is repeatedly diffused and reflected on the inner wall surface of the condenser, and the condensed light beam enters the optical fiber. Based on this light, the measurement unit measures the optical characteristics of the LED chip. The condenser is a so-called hemispherical integrating sphere in which a substantially spherical recess is formed.

JP 2006-234497 A

  However, the above-mentioned optical property measuring apparatus measures all LED chips because the LED chips, which are obtained by cutting (dicing) the semiconductor wafer and picking up each LED chip, are placed on the plate and measured individually. It takes a long time to do so and is inefficient.

  Here, it is also conceivable to individually measure in a group (hereinafter referred to as “a group of LED chips”) without picking up LED chips subdivided by dicing. However, in this case, since the LED chip is generally attached to the adhesive tape in order to prevent the dicing due to dicing, it is necessary to measure through the adhesive tape. In addition, in order to prevent the adhesive tape from being bent, it is necessary to place the adhesive tape on the plate to be stationary, and to bring the plate into close contact with the input port of the integrating sphere. Since the integrating sphere diffuses and reflects light to spatially integrate and make uniform, the ratio of the emitted light to the incident light is not high. For this reason, if the light reflected and attenuated when passing through the adhesive tape and the plate is made uniform with an integrating sphere, it takes a long time to measure in the measuring section, which is inefficient.

  The present invention has been proposed in view of the above circumstances. That is, an object of the present invention is to provide an LED chip optical characteristic measuring apparatus and an LED chip optical characteristic measuring method capable of efficiently measuring the optical characteristic of the LED chip.

  In the LED chip optical characteristic measuring apparatus according to the present invention, optical characteristics of a plurality of flip chip LEDs formed by dicing a semiconductor wafer on an adhesive tape are brought into contact with an electrode formed on an upper surface of the flip chip LED. In an optical characteristic measurement apparatus for an LED chip that is measured based on light that is emitted by being energized through a probe, an incident portion where the light emitted from the lower surface of the flip-chip LED is incident as incident light; A light pipe having an emission part from which incident light is emitted as emission light, a photodetector for detecting the emission light is provided on the emission part side, the incidence part is formed flat, and the electrode When a group of flip-chip LEDs is in contact with the probe, a group of flip-chip LEDs together with the adhesive tape is Placed on the incident portion, it is characterized in that.

  In the LED chip optical property measuring apparatus according to the present invention, the light pipe has a conical column shape in which the emission part is formed larger than the incidence part.

  In the LED chip optical property measuring apparatus according to the present invention, a transparent table through which the light is transmitted is provided in close contact with the incident portion, and the group of flip chip LEDs are placed on the transparent table together with the adhesive tape. It is characterized by that.

  The LED chip optical characteristic measuring apparatus according to the present invention is characterized in that a transmission diffusion member on which the emitted light is projected is provided between the emitting portion and the photodetector.

  The LED chip optical property measuring method according to the present invention is characterized in that the optical property of the flip chip LED is measured using the LED chip optical property measuring apparatus according to the present invention.

  The LED chip optical property measuring apparatus according to the present invention has the above-described configuration. According to this configuration, the incident light emitted from the flip-chip LED and incident on the light pipe is repeatedly reflected and scattered to be uniform, so that the ratio of the emitted light to the incident light is unlikely to decrease. Therefore, the optical characteristics of the flip chip LED can be measured efficiently.

  In addition, since the ratio of the emitted light to the incident light is unlikely to decrease with the light pipe, even when the light is incident through the adhesive tape, the light is uniformized and the measurement at the measuring unit can be performed in a short time. Therefore, a group of flip chip LEDs affixed to the adhesive tape can be placed on the incident portion of the light pipe, and the optical characteristics of the flip chip LED can be measured through the adhesive tape. Therefore, the optical characteristics of the flip chip LED can be measured efficiently.

  Moreover, since the incident part of the light pipe is formed flat, it functions as a measuring table. That is, when a group of flip-chip LEDs are placed on the incident portion and the probe contacts the electrode, the incident portion is formed flat, so that the adhesive tape can be applied without a plate due to the reaction to the pressing force from the probe. It does not flex and stops. Therefore, the optical characteristics of the flip chip LED can be accurately measured.

  In the LED chip optical property measuring apparatus according to the present invention, the light pipe has a conical column shape in which an emission part is formed larger than an incident part. According to this configuration, the light pipe has a smaller numerical aperture (NA) at the exit portion than the entrance portion, and can suppress the spread of the emitted light emitted from the exit portion. Therefore, the light emitted from the flip-chip LED has a large NA, whereas the light can be efficiently detected by a photodetector having a small NA.

  In the LED chip optical property measuring apparatus according to the present invention, a transparent table through which light is transmitted is provided in close contact with an incident portion, and a group of flip chip LEDs are placed on the transparent table together with an adhesive tape. According to this configuration, since the transparent table is generally larger than the group of flip chip LEDs and the adhesive tape, the adhesive tape is stationary by placing the group of flip chip LEDs together with the adhesive tape on the transparent table, And stable easily. Therefore, the optical characteristics of the flip chip LED can be measured accurately and easily.

  In the LED chip optical property measuring apparatus according to the present invention, a transmissive diffusing member on which the emitted light is projected is provided between the emitting portion and the photodetector. According to this structure, light can be made uniform by projecting on a diffuse reflection member, and light can be efficiently collected by the optical measuring device.

  The LED chip optical characteristic measuring method according to the present invention uses the above-described LED chip optical characteristic measuring apparatus. Therefore, the optical characteristics of the flip chip LED can be measured efficiently.

It is the schematic which shows the outline of the optical characteristic measuring apparatus of the LED chip which concerns on 1st embodiment of this invention. It is the schematic which shows the outline of the optical characteristic measuring apparatus of the LED chip which concerns on 2nd embodiment of this invention. It is the schematic which shows the outline of the reference example of this invention.

  Hereinafter, a first embodiment according to the present invention will be described with reference to the drawings. FIG. 1 shows an outline of an optical property measuring apparatus 10 for an LED chip according to a first embodiment of the present invention. Since FIG. 1 is a schematic diagram, each component is exaggerated for easy understanding of the present invention. 2 and 3 are the same.

  In FIG. 1, an LED chip optical property measuring apparatus 10 according to an embodiment of the present invention is suitable for measuring optical properties of a flip chip LED 1. The flip chip LED 1 is one LED chip obtained by dicing the semiconductor wafer 4 into individual pieces, and an electrode 2 is formed on the upper surface and a light emitting surface 3 is formed on the lower surface. A group of flip chip LEDs (hereinafter referred to as “a group of flip chip LEDs 5”) immediately after the semiconductor wafer 4 is diced are attached to the adhesive tape 6 in a group.

  The LED chip optical characteristic measuring apparatus 10 includes a transparent table 20 on which a group of flip chip LEDs 5 are mounted together with an adhesive tape 6, a probe 7 disposed on the upper surface side of the transparent table 20, and an incident portion on the lower surface side of the transparent table 20. A light pipe 30 attached in close contact with the light pipe 30, a transmission diffusion member 40 attached in close contact with the emitting portion 32 of the light pipe 30, a photodetector 50 for detecting light transmitted through the transmission diffusion member 40, and a light detector The light measuring device 51 measures the light detected at 50.

  The adhesive tape 6 is transparent, and the material is, for example, polyester, polyvinyl chloride, polyethylene or the like. The pressure-sensitive adhesive tape 6 has an upper surface (a surface on which a group of flip chip LEDs 5 is attached) as a pressure-sensitive adhesive surface, and is formed by applying a pressure-sensitive adhesive that is cured when irradiated with ultraviolet rays.

  The transparent table 20 is a transparent tempered glass having excellent uniformity, such as quartz glass or sapphire glass. The area of the transparent table 20 is formed larger than the group of flip chip LEDs 5 (semiconductor wafer 4). The transparent table 20 is formed to have a thickness that can transmit light at a predetermined angle and that ensures the strength. By transmitting the transparent table 20 at a predetermined angle, incident light is incident at an angle at which the light can be totally reflected inside the light pipe 30. The transparent table 20 has the adhesive tape 6 stationary on the upper surface together with a group of flip chip LEDs 5 by means of a suction device (not shown), a stationary device (not shown), or the like. The probe 7 is disposed on the upper surface side of the transparent table 20. The probe 7 is an electrode needle for contacting and energizing the electrode 2 of the flip chip LED 1, and the material is tungsten or the like.

  The light pipe 30 is formed in a solid or hollow columnar shape, and the shape is, for example, a columnar shape, an elliptical column shape, a cone shape, a polygonal column shape, a polygonal pyramid shape, a columnar shape with a cross-section star shape, or the like. The light pipe 30 has an incident portion 31 on the upper end side where light emitted from the flip chip LED 1 is incident as incident light, and an emission portion 32 on the lower end side where incident light is emitted as emitted light. The incident part 31 has a flat part 33 formed flat, and is attached in close contact with the lower surface of the transparent table 20. The incident part 31 (flat part 33) has a larger area than the flip chip LED1. The injection part 32 is attached with the transmission diffusion member 40 in close contact therewith.

  The light pipe 30 preferably has a tapered quadrangular pyramid shape in which the area of the emission part 32 is larger than the area of the incident part 31. For example, the area of the incident part 31 (flat part 33) is about 4 × 4 mm, the area of the emission part 32 is about 12 × 12 mm, and the total length is about 50 mm. In this case, since the NA of the light pipe 30 becomes smaller in accordance with the reciprocal of the area ratio between the incident part 31 and the emission part 32, the NA of the emission part 32 becomes ３ of the incident part 31. The area ratio is appropriately changed according to the NA of incident light, and the total length is appropriately changed according to the angle of total reflection.

  The transmission diffusion member 40 is, for example, a plate-shaped ground glass, and the light emitted from the emission unit 32 of the light pipe 30 is projected thereon. The transmissive diffusing member 40 may be attached to the light receiving portion of the photodetector 50 in addition to being attached in close contact with the emitting portion 32. In this case, the distance between the transmissive diffusion member 40 and the photodetector 50 is determined from the NA of the photodetector 50 and the light distribution of the emitted light emitted from the light pipe 30. The transmission diffusion member 40 is arbitrarily attached and is attached according to the condition of the light distribution of the emitted light.

  The light detector 50 is, for example, an optical fiber, and the light emitted from the light emitting portion 32 of the light pipe 30 is condensed on the light receiving portion, and the light is conveyed to the light measuring device 51. The distance between the photodetector 50 and the emission part 32 of the light pipe 30 is arbitrary, and is appropriately adjusted according to the specifications of the photodetector 50. The optical measuring device 51 processes incident light as a signal and measures optical characteristics such as chromaticity, radiant flux, luminous flux, and spectral density.

  The transparent table 20, the probe 7, and the light pipe 30 are connected to moving mechanisms (not shown), respectively, and interlocked with the moving mechanisms. The moving mechanism moves them in the X, Y, and Z axial directions and rotates them around the Z axis.

  Next, a second embodiment according to the present invention will be described with reference to the drawings. FIG. 2 shows an outline of an LED chip optical property measuring apparatus 11 according to the second embodiment of the present invention. In the following description, only the configuration different from the above-described LED chip optical property measuring apparatus 10 will be described, and the description regarding the same configuration will be omitted.

  In FIG. 2, the optical property measurement apparatus 11 does not include the transparent table 20. That is, the incident portion 31 of the light pipe 30 is a flat portion 33 formed flat, and a group of flip chip LEDs 5 are placed on the flat portion 33 together with the adhesive tape 6. A portion of the adhesive tape 6 and the flip chip LED 1 that does not fall within the flat portion 33 is stopped by an adsorption device or a support device (not shown).

  FIG. 3 shows an outline of an optical property measuring apparatus 12 for LED chips, which is a reference example of the present invention. In FIG. 3, the LED chip optical property measuring device 12 is provided with the transmission diffusion member 40 in close contact with the lower surface of the transparent table 20, and the light pipe 30 is not provided.

  In each embodiment described above, the light pipe 30 may be replaced with a lens (not shown). As the lens, for example, an F-theta lens (Fθ lens) and a condensing lens are used. The light emitted radially from the flip chip LED 1 is made uniform by the lens and condensed.

  Next, an LED chip optical characteristic measuring method using the LED chip optical characteristic measuring apparatus 10 according to the embodiment of the present invention will be described. In the following description, when the LED chip optical property measuring device 11 is used, only the method different from that of the LED chip optical property measuring device 10 is described, and the description of the similar method is omitted. Yes.

  A group of flip chip LEDs 5 together with the adhesive tape 6 is placed on the upper surface of the transparent table 20. The adhesive tape 6 is stopped on the transparent table 20 by using an adsorption device or a stationary device.

  The probe 7 is arranged on the upper surface side of the transparent table 20 in conjunction with the moving mechanism, and the light pipe 30 is arranged on the lower surface side of the transparent table 20. The probe 7 is made to face an arbitrary flip chip LED 1 in the group of flip chip LEDs 5, and the incident portion 31 of the light pipe 30 is brought into close contact with the lower surface of the transparent table 20. In the case of the above-described LED chip optical property measuring device 11, a group of flip chip LEDs 5 are placed on the flat portion 33 of the light pipe 30 together with the adhesive tape 6, and the adhesive tape 6 is stopped by an adsorption device or a support device.

  The probe 7 is brought into contact with the electrode 2 of the flip chip LED 1 and energized. The light emitting surface 3 of the flip chip LED 1 emits light, and the light passes through the adhesive tape 6 and the transparent table 20. Light enters from the incident portion 31 of the light pipe 30 as incident light, and exits from the emission portion 32 as emitted light. In the light pipe 30, light is scattered and uniformed inside. The homogenized light is emitted from the emitting portion 32 as emitted light and is projected onto the transmissive diffusing member 40. The transmissive diffusing member 40 makes the light uniform by projecting the emitted light even when the influence of the brightness distribution remains inside the emitting part 32 of the light pipe 30.

  The light 50 that has been transmitted through and condensed through the transmissive diffusing member 40 is detected and conveyed to the light measuring device 51, and the light measuring device 51 measures the optical characteristics of the flip chip LED 1 based on the light.

  The LED chip optical characteristic measuring apparatus 10 repeats the above operation, moves the probe 7 and the light pipe 30 to the adjacent flip chip LED 1 and arranges them, and measures the optical characteristics. In the case of using the optical characteristic measuring device 11 of the LED chip, when measuring the optical characteristic of the adjacent flip chip LED 1, the light pipe 30 is moved away from the adhesive tape 6 in the Z-axis direction and moved in the XY direction, and again the Z-axis. Move in a direction or slide on the lower surface of the adhesive tape 6.

  Next, effects of the above-described embodiments will be described.

  As described above, according to the first embodiment, the LED chip optical property measuring apparatus 10 includes the transparent table 20 on which the group of flip chip LEDs 5 are placed together with the adhesive tape 6, and the probe disposed on the upper surface side of the transparent table 20. 7. Light pipe 30 in which the incident portion 31 is attached in close contact with the lower surface side of the transparent table 20, the transmission diffusion member 40 in close contact with the emission portion 32 of the light pipe 30, and the light transmitted through the transmission diffusion member 40 The light detector 50 detects the light and the light measuring device 51 that measures the light detected by the light detector 50. According to this configuration, the incident light emitted from the flip chip LED 1 and incident on the light pipe 30 is repeatedly reflected and scattered to be uniform, so that the ratio of the emitted light to the incident light is unlikely to decrease. Therefore, the optical characteristics of the flip chip LED 1 can be measured efficiently.

  Further, since the ratio of the emitted light to the incident light is unlikely to be lowered according to the light pipe 30, even when light is incident through the adhesive tape 6 and the transparent table 20, the light can be uniformized and measured in a short time. Therefore, a group of flip chip LEDs 5 attached to the adhesive tape 6 can be placed on the transparent table 20, and the optical characteristics of the flip chip LED 1 can be measured through the adhesive tape 6 and the transparent table 20. Therefore, the optical characteristics of the flip chip LED 1 can be measured efficiently.

  Further, according to the configuration described above, since the transparent table 20 is larger than the group of flip chip LEDs 5 (semiconductor wafer 4), the group of flip chip LEDs 5 is placed on the transparent table 20 together with the adhesive tape 6 to thereby adhere. The tape 6 is stationary and can be easily stabilized. Therefore, the optical characteristics of the flip chip LED 1 can be measured accurately and easily.

  Moreover, since the light pipe 30 is columnar, the optical characteristic measuring device can be reduced in size. If the device corresponding to the light pipe 30 is a sphere, the flip chip LED 1 is disposed at the center of the incident portion. Here, of the group of flip chip LEDs 5, the peripheral flip chip LED 1 is at the center of the incident portion. When arranged, almost half of the sphere protrudes outside the periphery of the group of flip chip LEDs 5. Therefore, it is necessary to design the optical characteristic measuring device by forming a space for arranging the spheres outside the periphery of the group of flip chip LEDs 5, and the optical characteristic measuring device is enlarged.

  According to the second embodiment, since the incident portion of the light pipe 30 is the flat portion 33 formed flat, when the group of flip chip LEDs 5 are placed on the flat portion 33 and the probe 7 contacts the electrode 2. By the reaction against the pressing force from the probe 7, the adhesive tape 6 does not flex and stops. Therefore, the optical characteristics of the flip chip LED 1 can be accurately measured.

  Moreover, since the transparent table 20 is not provided, reflection and attenuation of light when passing through the transparent table 20 are suppressed. Therefore, the optical characteristics of the flip chip LED 1 can be measured efficiently.

  According to each embodiment, it is a tapered quadrangular pyramid shape in which the area of the emission part 32 is formed larger than the area of the incident portion 31. According to this configuration, the NA of the light pipe 30 is reduced according to the reciprocal of the area ratio between the incident part 31 and the emission part 32. For this reason, the NA of the emitting part 32 is smaller than that of the incident part 31, and the spread of the emitted light emitted from the emitting part 31 of the light pipe 30 can be suppressed. Therefore, the light emitted from the flip-chip LED 1 has a large NA, whereas the photodetector 50 having a small NA can detect the light efficiently.

  According to each embodiment, the light diffusing member 40 is attached to the injection portion 32 of the light pipe 30 in close contact. According to this configuration, even when the influence of the brightness distribution remains inside the emission part 32 of the light pipe 30, the emitted light is made uniform by projecting it onto the transmission diffusion member 40. Therefore, the light can be efficiently collected by the optical measuring device 51.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited to the said embodiment. The present invention can be modified in various ways without departing from the scope of the claims.

1 Flip chip LED
2 electrode 3 light emitting surface 4 semiconductor wafer 5 group of flip chip LEDs
DESCRIPTION OF SYMBOLS 6 Adhesive tape 7 Probe 10, 11, 12 The optical characteristic measuring apparatus of LED chip 20 Transparent table 30 Light pipe 31 Incident part 32 Injecting part 33 Flat part 40 Transmission diffusion member 50 Photo detector 51 Optical measuring instrument

Claims (5)

The optical characteristics of a plurality of flip chip LEDs formed by dicing a semiconductor wafer on an adhesive tape are based on light emitted by energization through a probe in contact with an electrode formed on the top surface of the flip chip LED. In the LED chip optical property measuring device to be measured,
A light pipe having an incident portion where the light emitted from the lower surface of the flip-chip LED is incident as incident light and an emission portion where the incident light is emitted as emitted light;
A photodetector for detecting the emitted light is provided on the emitting part side,
When the incident part is formed flat and the electrode is brought into contact with the probe, a group of flip chip LEDs which are the plurality of flip chip LEDs are placed on the flat incident part together with the adhesive tape,
An optical property measuring apparatus for an LED chip. The light pipe has a conical column shape in which the emission part is formed larger than the incident part.
The optical property measuring apparatus for an LED chip according to claim 1. A transparent table through which the light is transmitted is provided in close contact with the incident portion,
The group of flip chip LEDs are placed on the transparent table together with the adhesive tape,
3. The LED chip optical property measuring apparatus according to claim 1, wherein the LED chip has optical characteristics. A transmission diffusing member on which the emitted light is projected is provided between the emitting portion and the photodetector;
The LED chip optical property measuring apparatus according to claim 1, wherein the optical characteristic measuring device is an LED chip. The optical property of the flip chip LED is measured using the optical property measurement apparatus for an LED chip according to any one of claims 1 to 4.
A method for measuring optical characteristics of an LED chip.

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